Dissertations / Theses on the topic 'Resistant Tuberculosis'

The number of children globally who develop drug-resistant tuberculosis is unclear, in part due to diagnostic challenges and limited resistance testing, and in part because recording and reporting is not comprehensive. Large numbers of children, however, are exposed to drug resistant bacilli each year and it is clear that the very young and those immune-compromised are vulnerable to developing disease. Few studies have looked at the progression from exposure to infection or from infection to disease in the child contacts of adults with drug-resistant tuberculosis. It is uncertain which factors influence this progression and also whether any interventions can prevent it. Finally, few studies have analysed the presentation, treatment and outcome of children with disease. This thesis starts by reviewing what is published regarding drug-resistant tuberculosis in children. This includes systematic reviews of the management of children exposed to drug resistant tuberculosis as well as the management of those with multi drug-resistant tuberculosis disease. It reviews what is known regarding the second-line tuberculosis drugs in children and then clarifies the definitions that are used throughout the rest of the work. The thesis then systematically examines each of the stages from infection to disease with a series of inter-related studies. The first study attempts to quantify the burden of drug resistance in the context that the work is carried out. The following study investigates the risk factors for infection and prevalent disease in children exposed to a multi drug-resistant tuberculosis source case. This is followed by two studies which explore the transmission of drug-resistant bacilli from adults to children. The identification and referral patterns and obstacles to referral for exposed children are examined through operational studies that include qualitative and quantitative components. A descriptive cohort study assesses the toxicity and efficacy of a standardised preventive treatment regimen given to child contacts. The final part of the thesis includes a series of studies to investigate the treatment of drug resistant tuberculosis disease in children and the adverse effects of the second-line medications.

Thesis (MTech (Biomedical Technology))--Cape Peninsula University of Technology, 2010<br>The World Health Organisation estimates that nine million people are infected with tuberculosis (TB) every year of which ninety-five percent live in developing countries. Africa has one of the highest incidences of TB in the world. but few of its countries are equipped to diagnose drug-resistant TB. This study aimed to develop a robust. yet simple and cost-effective assay. which would require minimal sophisticated instrumentation and specialised personnel that would make drug sensitivity screening for multi-drug resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) accessible to resource-poor high-burden settings. A four-quadrant colorimetric agar plate method was developed which showed good specificity (97.3%-100%) and sensitivity (77.8%-100%) compared to the polymerase chain reaction (PCR) method used as gold standard. Agreement between the methods. using Simple Kappa Coefficients. ranged between very good and excellent. all with high statistical significance (P < 0.0001). The currently used BACTEC MGIT SIREN sensitivity assay coupled with the E-test® strip method. as routinely used in the TB reference laboratory. was compared and showed excellent comparison with the newlydeveloped plate method. for each antibiotic tested. as well as the resultant monoresistant, MDR- or XDR-TB diagnoses. Moreover. the new method was found to be extremely cost-effective. priced at half the cost of a peR assay. These four quadrant plates. with a colorimetric indicator and selected antibiotics. can be considered as an economic altemative or a complimentary method for laboratories wishing to reduce the cost and complexity for TB drug sensitivity testing. Routine diagnostic testing would thus be made more accessible and affordable to laboratories that are not presently diagnosing drug resistant TB. therefore enhancing case detection and treatment in the resource-poor settings hardest hit by this curable disease.

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-08-26T18:01:43Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) NILMA MEDTROP VD.pdf: 2060397 bytes, checksum: 801ad4896a8a5f3c544547167d27652d (MD5)<br>Made available in DSpace on 2016-08-26T18:01:43Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) NILMA MEDTROP VD.pdf: 2060397 bytes, checksum: 801ad4896a8a5f3c544547167d27652d (MD5) Previous issue date: 2015-02-05<br>A tuberculose (TB) é a doença mais comum da humanidade. Atualmente, a Organização Mundial de Saúde estimou nove milhões de novos casos e um milhão e meio de mortes decorrentes da doença. A rápida expansão da resistência aos fármacos antituberculose tem prejudicado o controle global da TB, constituindo um grave problema de Saúde Pública. No Brasil, a semelhença de outros países endêmicos, tem-se observado uma variabilidade na prevalência de resistência e no estado da Paraíba (PB) não há dados recentes e concisos. Dessarte, esse estudo objetivou verificar a prevalência de resistência do Mycobacterium tuberculosis aos fármacos do esquema de primeira linha do tratamento da TB utilizados no Brasil e a frequência de fatores de risco - sexo, idade, tratamento prévio e ingesta alcóolica - em pacientes adultos com diagnóstico de TB pulmonar resistente (TBP), atendidos em serviço de referência na PB durante o período de 01 de janeiro de 2003 a 31 de dezembro de 2013. Para obtenção dos dados, utilizou-se formulário padronizado, preenchido, retrospectivamente, a partir das informações contidas nos prontuários dos pacientes atendidos no período do estudo. Foram notificados 69 casos, com prevalência de 0,5%. Evidenciou-se 17,4% de mono, 14,5% de poli e 68,1% de multirresistência. A resistência à isoniazida (INH) mostrou-se importante, tanto isolada, quanto em associações; bem como e, principalmente, a TB multirresistente (TBMR). Perante os fatores de risco, o sexo masculino (73,9%), a faixa etária de 40 a 49 anos (46,4%), a realização de tratamento prévio (98,5%) e a ingesta alcóolica (57,4%) foram os de maior ocorrência. Todavia, não expressaram significância estatística no estudo realizado tendo a PB como cenário. O desfecho foi a cura para 44,9% dos casos; no entanto, o abandono ao tratamento foi considerável, principalmente para a TBP monorresistente (33,3%). As características sociodemográficas compreenderam: a cor da pele parda (68,5%), o estado civil casado (50,9%), o nível de instrução até o fundamental (67,3%) e a procedência do interior da PB (78,2%). Quanto à coinfecção com HIV/AIDS, ocorreu em 14,5%; no entanto, nesse grupo a TBMR, também, foi mais frequente. Desta feita, mais estudos são imprescindíveis no intuito de investigar genotipicamente a resistência da TB no estado da PB, visto que alguns estudos genéticos têm reportado mutações em cepas resistentes à rifampicina (RMP), estando associada a maior transmissibilidade e a resistência à INH tem sido associada com mutações de vários genes. Assim, correlacionando com outros estados e países a fim de colaborar com o enfrentamento da doença na busca do controle e cura extensiva a todos. Por outro lado, há necessidade de fortalecimento das ações do programa de controle da TB, tanto em nível estadual, quanto nos municípios.<br>Tuberculosis (TB) is the most common disease of humanity. Currently, the World Health Organization estimated nine million new cases and a million and a half deaths from the disease. The rapid spread of resistance to antituberculosis drugs has undermined the global TB control, constituting a serious public health problem. In Brazil, as other endemic countries, it has been observed variability in the prevalence of resistance and the state of Paraíba (PB) no recent and accurate data. Thus, this study aimed to determine the prevalence of resistance of the Mycobacterium tuberculosis to first-line drugs in TB treatment regimen used in the Brazil and frequency of risk factors - gender, age, prior treatment and alcoholic intake - in adults patients diagnosed with resistant pulmonary TB (PTB), treated on reference service in PB during the January 1, 2003 to December 31, 2013. To obtain the data, it used standardized form filled out retrospectively from the information contained in the medical records of patients seen during the study period. Were reported 69 cases, with a prevalence of 0.5%. Revealed a 17.4% to mono, 14.5% to poly and 68.1% to multidrug resistance. The isoniazid (INH) resistance was found to be important, both isolated, as in associations; as well as, and especially multidrug resistant TB (MDR-TB). In view of the risk factors, males (73.9%), the age group 40 -49 years (46.4%), the realization of previous treatment (98.5%) and alcoholic intake (57.4%) were the most frequent. However, did not express statistical significance in the study with the PB as a scenario. The outcome was the cure for 44.9% of cases; however, abandon to treatment was significant, particularly for mono resistant PTB (33.3%). The sociodemographic characteristics included: dark brown skin (68.5%), married status (50.9%), level of education up to primary (67.3%) and the origin from the interior of PB (78.2%). The co-infection with HIV/AIDS occurred in 14.5%; however, this group the MDR-TB also was more frequent. This time, more studies are essential in order to investigate genotypically the TB resistance in the state of PB, as some genetic studies have reported mutations in strains resistant to rifampicin (RMP) and are associated with increased transmissibility and INH resistance has been associated with mutations multiple genes. Thus, correlating with other states and countries to collaborate with coping with the disease in the search of control and extensive cure to all. On the other hand, there is need to strengthen the actions of the TB control program at the state level and in the municipalities.

The emergence and spread of multi-drug resistant (MDR-TB) and extensively drugresistant tuberculosis (XDR-TB) are a major medical and public problem threatening the global health. The objectives of this study were to (i) determine the prevalence of MDR-TB and XDR-TB in the Eastern Cape; (ii) analyze patterns of gene mutations in MDR-TB and (iii) identify gene mutations associated with resistance to second line injectable drugs in XDR-TB isolates. A total of 1520 routine sputum specimens sequentially received within a period of 12 months i.e. February 2012 to February 2013 from all MDR-TB and XDR-TB patients treated by Hospitals and clinics in the Eastern Cape were included in this study, of which 1004 had interpretable results. Samples were analyzed with the Genotype MTBDRplus VER 2.0 assay kit (Hain Lifescience) for detection of resistance to Rifampicin and Isoniazid while solid and liquid culture drug susceptibility tests were used for ethambutol, streptomycin, ethionamide, ofloxacin, capreomycin and amikacin. PCR and sequence analysis of short regions of target genes gyrA, (encode subunit of DNA topoisomerase gyrase), rrs (16S rRNA) and tlyA (encodes a 2’-O-methyltransferase) were performed on 20 XDR-TB isolates. MTBDRplus kit results and drug susceptibility tests identified 462 MDR-TB, 284 pre-XDR and 258 XDR-TB isolates from 267 clinics and 25 hospitals in the Eastern Cape. There was a high frequency of resistance to streptomycin, ethionamide, amikacin, ofloxacin and capreomycin. Mutation patterns indicated differences between the health districts as well as differences between the facilities within the health districts. The most common mutation patterns observed were: (i) ΔWT3, ΔWT4, MUT1 [D516V+del515] (rpoB), ΔWT, MUT1 [S315T1] (katG), ΔWT1 [C15T] (inhA) [39 MDR, 204 XDR-TB and 214 pre XDR-TB isolates], (ii) ΔWT8, MUT3 [L533P+S531L] (rpoB), ΔWT, MUT1 [S315T1] [145 MDR, 18 pre-XDR and 3 XDR-TB solates] and (iii) ΔWT3, WT4 [D516Y+del515] (rpoB), ΔWT, MUT1 [S315T1] (katG) [75 MDR, 1 pre-XDR and 7 XDR-TB isolates]. Mutations in inhA promoter regions were strongly associated with XDR-TB isolates. Two thirds (66.6 percent (669/1004) of the isolates had inhA mutations present with 25.4 percent (170/669) found among the MDR isolates, 39.2 percent (262/669) among the pre-XDR isolates and 35.4 percent (237/669) among the XDR-TB isolates, which implies that these resistant isolates are being spread by transmission within the community and circulating in the province. There was good correlation between XDR-TB drug susceptibility test results and sequence analyses of the gyrA and rrs genes. The majority of XDR-TB isolates contained mutations at positions C269T (6/20) and 1401G (18/20) in gyrA and rrs genes respectively. Sequence analysis of short regions of gyrA and rrs genes may be useful for detection of fluoroquinolone and amikacin/ kanamycin resistance in XDR-TB isolates but the tlyA gene is not a sensitive genetic marker for capreomycin resistance. This study highlighted the urgent need for the development of rapid diagnostics for XDR-TB and raised serious concerns regarding ineffective patientmanagement resulting in ongoing transmission of extremely resistant strains of XDRTB in the Eastern Cape suggesting that the Eastern Cape could be fast becoming the epicenter for the development of Totally Drug-resistant Tuberculosis (TDR-TB) in South Africa.

Tuberculosis (TB) is a highly infectious disease that causes the second highest mortality rate in human worldwide. The emergence of multi-drug resistance tuberculosis (MDR-TB) leads to a major public health problem in controlling TB-caused mortality. Pyrazinamide (PZA) is an important first-line drug in the treatment of MDR-TB. However, since the challenge in performing susceptibility test on PZA, World Health Organization has not published any data on the prevalence of PZA resistance in Mycobacterium tuberculosis (M. tuberculosis). Since the occurrence of PZA resistance makes MDR-TB more difficult to treat with poor prognosis, rapid detection method in PZA resistance is urgently needed. Since pncA mutation is highly associated with up to 98% PZA resistant M. tuberculosis strains, it is worthwhile to develop rapid molecular method for detecting PZA resistance. This study aims to identify the mutations in PZA resistant M. tuberculosis strains. The first part of this study aims to characterize the pattern of pncA mutation among PZA-resistant and PZA-susceptible M. tuberculosis using Sanger sequencing method. Among all clinical isolates, 12 out of 29 cases of M. tuberculosis were resistant to PZA. All PZA-resistant M. tuberculosis strains harbored pncA mutation, whereas no known mutations were found among those PZA-susceptible strains, giving the positive predictive value to be 100%. Eight mutation patterns were found among 12 resistant isolates. Four of these pncA mutations have not been described previously by other studies. Study also characterizes the pattern of pncA mutation in 19 sputum specimens, with 2 mutation patterns found. Overall 10 mutation patterns were found in this study. Results show that the mutation of pncA gene is highly associated with PZA-resistant M. tuberculosis. Results also suggest the scattered and more extensive mutations in pncA gene that confer PZA resistance to M. tuberculosis. The second and the last part of this study aims to evaluate the possibility of using molecular method to detect PZA resistance in routine clinical laboratory. Results show that using molecular sequencing to detect PZA resistance can shorten the turnaround time to about 3-4 working days. Since mutation of pncA was scattered along the entire pncA gene, using DNA sequencing approach may be the best strategy for the rapid detection of PZA resistance in M. tuberculosis.<br>published_or_final_version<br>Medical Sciences<br>Master<br>Master of Medical Sciences

Objective. Since the 1980's the incidence of tuberculosis (TB) in Montreal has remained at 11 cases per 100,000. In order to improve TB prevention and control programs, we sought to identify predictors of tuberculosis drug-resistance and to describe the epidemiology of TB drug resistance on the island of Montreal.<br>Study design. Retrospective descriptive analysis Study population. All culture proven TB patients reported to the Montreal Regional Health Board aged 0--49 for 1992--1994 and 0--18 years for 1995.<br>Results. Drug resistant TB was found in 18.3% of culture-proven TB cases. The rate of INH resistance in our study cohort was 10.6%. Two percent of TB cases were found to have MDR-TB. Only 3 TB cases (0.9%) in our study cohort developed acquired drug resistance over the study period. Previous history of TB was associated with a 3.9 times greater risk of drug resistant TB.<br>Conclusions. Drug resistance is a significant problem in Montreal that continues to hinder TB treatment and control. Previous history of tuberculosis is a strong predictor of drug resistance. In addition, immigration from individual countries was not associated with an increase in the rate of drug resistance. Nonetheless, country-specific drug resistance rates may serve to predict the likelihood of drug resistant TB among the foreign-born in Canada.

Mycobacterium tuberculosis (Mtb) poses a global health catastrophe that has been compounded by the emergence of highly drug resistant Mtb strains. We used whole genome sequencing (WGS) to directly compare the accumulation of mutations in Mtb isolated from cynomolgus macaques with active, latent and early reactivation disease. Based on the distribution of single nucleotide polymorphisms (SNPs) observed, we calculated the mutation rates for these disease states. Our data suggest that during latency, Mtb acquires a similar number of chromosomal mutations as would be expected to emerge in a logarithmically growing culture over the same period of time despite reduced bacterial replication during latent infection. The pattern of polymorphisms suggests that the mutational burden in vivo is due to oxidative DNA damage. We next sought to determine why some strains of Mtb are preferentially associated with high-level drug resistance. We demonstrate that Mtb strains from the East Asian lineage acquire drug resistances in vitro more quickly than Mtb strains from the Euro-American lineage. Their higher drug resistance rate in vitro reflects a higher basal mutation. Moreover, the in vitro mutation rate correlates well with the bacterial mutation rate in humans as determined by whole genome sequencing of clinical isolates. Finally, using an agent-based model, we show that the observed differences in mutation rate predict a significantly higher probability of multi-drug resistance in patients infected with East Asian lineage strains of Mtb. Lastly, we sought to determine the mechanisms Mtb uses to proofread nascently polymerized DNA. Through fluctuation analysis of deletion mutants of two potential \(polIII\epsilon\) homologs, we demonstrate that neither is responsible for the maintenance of DNA replication fidelity. To explore the possibility that one of these homologs, Rv3711c, participates in an unknown redundant pathway, we used transposon capture and sequence (TraCS) to identify genes conditionally essential in an Rv3711c deletion mutant. Our analysis suggests that while Rv3711c does not participate in proofreading, it may act in an alternative novel DNA repair pathway. Taken together, our fluctuation analysis and TraCS data suggest that mycobacteria do not use canonical methods of proofreading to maintain genomic fidelity.

Includes abstract.<br>Includes bibliographical references (leaves 161-168).<br>There are few data for treatment-related outcomes in patients with XDR tuberculosis in settings with high HIV prevalence. We reviewed the case records of 227 consecutively diagnosed South African patients with XDR-TB between 2002 and 2008, and analysed the records of another 115 patients, retrospectively, for adverse drug reactions (ADRs). It was found that a significant proportion of XDR-TB patients are HIV unrelated, and prognosis, regardless of HIV status, poor. Nevertheless, survival in HIV infected patients is better than previously reported, and treatment with HAART improves outcomes. The frequency of ADR’s with XDR-TB treatment regimens is high, often severe, and negatively impacts on culture conversion outcomes. These data have implications for the formulation of recommendations for control programmes in resource-poor settings.

Submitted by Maria Creuza Silva (mariakreuza@yahoo.com.br) on 2014-10-13T18:11:18Z No. of bitstreams: 1 DISS MP ROSANGELA MENESES. 2010.pdf: 1029228 bytes, checksum: a495ab1d732bfbe849331458f7d36a37 (MD5)<br>Approved for entry into archive by Maria Creuza Silva (mariakreuza@yahoo.com.br) on 2014-10-13T18:13:21Z (GMT) No. of bitstreams: 1 DISS MP ROSANGELA MENESES. 2010.pdf: 1029228 bytes, checksum: a495ab1d732bfbe849331458f7d36a37 (MD5)<br>Made available in DSpace on 2014-10-13T18:13:21Z (GMT). No. of bitstreams: 1 DISS MP ROSANGELA MENESES. 2010.pdf: 1029228 bytes, checksum: a495ab1d732bfbe849331458f7d36a37 (MD5)<br>Introdução: Este estudo analisou o perfil da resistência aos medicamentos contra a tuberculose, a partir da participação do estado da Bahia no II Inquérito Nacional de Resistência a Drogas em Tuberculose realizado nos anos 2006 e 2007. Método: Estudo transversal, do tipo descritivo, exploratório, realizado em 16 municípios do estado da Bahia. Foram incluídos os sintomáticos respiratórios que tiveram tuberculose confirmada por baciloscopia e cultura e foram notificados no SINAN. Foi estimada a prevalência de resistência (primária, adquirida, multirresistência, monorresistência a Isoniazida) e analisadas associações segundo sexo, idade, raça/cor, escolaridade e comorbidades. Resultados: Entre os 687 casos de tuberculose estudados e com informações disponíveis no SINAN, 67,1% eram do sexo masculino; 52,4% estavam na faixa etária ≥25 e < 45 anos, 87,3% eram não brancos (562/644) e as comorbidades identificadas foram 20,8% HIV+, 1,2% com Aids, 17,2% com problemas de alcoolismo, 4,4% com diabetes e 1,5% com doença mental. Verificou-se que a resistência primária foi 10,59% e a resistência adquirida foi 16,44%. A multirresistência (MR) global foi observada em 1,3% dos pacientes, a MR primária de 0,81%, a MR adquirida de 5,47% e a monorresistência a isoniazida foi 3,8%. Considerações Finais: Concluiu-se que a multirresistência aos tuberculostáticos na Bahia é baixa, entretanto as prevalências da resistência primária e da resistência adquirida são altas. A análise destes resultados poderá colaborar na definição de estratégias para o efetivo controle da doença no estado e sugere-se que novas investigações busquem identificar os fatores que contribuem para a resistência primária, indicador da ocorrência da transmissão da TBMR na comunidade.<br>Introduction: This study analyzed the profile of drug resistance for tuberculosis in Bahia, from participation in the Second National Survey of Drug Resistance in Tuberculosis held in years 2006 and 2007 with the participation of 16 municipalities, including the capital. Method: Cross sectional, descriptive, exploratory, conducted in 16 counties of the state of Bahia. We included symptomatic patients who had TB confirmed by sputum smear and culture were reported in SINAN. It was estimated the prevalence of resistance (primary, acquired, multidrug resistance, a single drug isoniazid) and analyzed associations by gender, age, race, education, and comorbidities. Results: Among 687 cases of tuberculosis studied and information available from SINAN, 67.1% were male, 52.4% were aged ≥ 25 and <45 years, 87.3% were non-whites (562 / 644) and comorbidities identified HIV were 20.8%, 1.2% with AIDS, 17.2% with alcohol abuse, 4.4% to 1.5% with diabetes and mental illness. It was found that the primary resistance was 10.59% and 16.44% was acquired resistance. The multidrug resistance (MDR) rate was observed in 1.3% of patients, the primary of 0.81% MR, MR gained 5.47% and single drug isoniazid was 3.8%. Conclusion: We concluded that the multiresistance to antitubercular drugs in Bahia is low, however the prevalence of primary resistance and acquired resistance are high. Analysis of these results may assist in developing strategies for effective disease control in the state and it is suggested that further research can identify factors that contribute to primary resistance, indicating the occurrence of transmission of MDR-TB in the community.

Background: There is a dearth of information regarding prevalence of extensively drugresistant tuberculosis (XDR-TB) in Africa. Although countries in Africa conduct national tuberculosis surveys on a regular basis, this information has not been systematically reviewed to ascertain the overall prevalence of XDR-TB in Africa. Methods: The study aimed to perform a systematic review and meta-analysis of the prevalence and factors associated with prevalence of pulmonary XDR-TB among adults in Africa. Eligible studies, published between 2006 and 2018, were sourced from various electronic databases including PubMed, Scopus, and Web of Science. Meta-analysis was performed using STATA (version 14.2) statistical software. The protocol of this review was registered with PROSPERO, reg No CRD42018117037. Result: A total of 6242 records were retrieved. Forty-eight studies were screened for eligibility and seven, which varied in terms of country setting and study design, were included. The prevalence of XDR-TB is 4% (95%CI 2-7) among participants tested for second-line anti-TB drug resistance, and 3% (95%1-6) among participants with drug resistant TB. The prevalence of XDR-TB was 7% (95%CI 1-18) among participants with MDR-TB. A few studies reported on the factors associated with the prevalence of XDR-TB. Discussion: The reported prevalence of XDR-TB among participants tested for second-line anti-TB drug resistance is low compared to WHO estimates. The systematic review underscores a dearth of studies depicting the reality regarding the prevalence of XDR-TB in Africa. Policymakers and stakeholders interested in drug-resistant TB should apply prudence when considering XDR-TB prevalence reported for Africa.

Tuberculosis (TB) is a potentially fatal contagious disease that can affect almost any part of the body but is mainly an infection of the lungs. It is caused by micro-organisms of the Mycobacterium tuberculosis complex. It is the second greatest killer worldwide due to a single infectious agent, after the Human Immunodeficiency Virus (HIV). Without treatment, fatality is 50% in immune competent persons. TB remains the leading cause of death among HIV positive persons, causing one fifth of the deaths. The World Health Organization estimates that one third of the world population is infected by this micro-organism but only 5 to 10% develop TB disease. Nevertheless, this enormous reservoir leads to around 1.4 millions deaths annually. Standard curative treatment lasts at least 6 months and includes 4 different drugs. Toxicity of the drugs leading to (severe) adverse events and the long duration of the daily administration challenges patient’s compliance. Subinhibitory concentration of the drugs (due to poor adherence) can induce resistance of the mycobacteria to the provided drugs. Unlike most bacteria where resistance is acquired by plasmids, drug resistance of mycobacteria is obtained by genomic mutations. “Multi drug-resistant tuberculosis (MDR-TB)” is strictly defined as TB resistant to specifically isoniazid and rifampicin, the two main first line drugs. “Extensively drug resistance (XDR)” is defined as MDR-TB with additional resistance to any of the fluoroquinolones (such as ofloxacin or moxifloxacin) and to at least one of three injectable second-line drugs (amikacin, capreomycin or kanamycin). The increase of MDR-TB represents an enormous challenge to Public Health globally. This research examined different aspects of tuberculosis resistance performed in the Belgian National Reference Center, a clinical laboratory setting. <p><p>First of all, a profound analysis of the MDR-TB situation in Belgium was conducted. It is the first retrospective population-based survey of MDR-TB in Belgium, covering a 15-year period (1994-2008). It comprises 174 patients representing more than 80% of the culture positive MDR-TB patients reported to the Belgian register, thus this study is considered of national relevance. It includes bacteriological and molecular data on the isolates as well as clinical aspects of the patients and treatment results. Considering only the patient’s first MDR-TB isolate, an increase over time was observed in the number of isolates resistant to a second-line drug as well as the total number of drugs each isolate was resistant to. XDR-TB was detected since 2002 and panresistant TB (resistant to every available antituberculosis drug) since 2009. Overall, a successful treatment outcome was obtained for 67.8% of the MDR-TB cases. Drug susceptibility testing (DST) of Mycobacterium tuberculosis to first line drugs (isoniazid, rifampicin, ethambutol and pyrazinamide) in liquid culture medium has a turn around time of at least two weeks, after identification of the positive culture (obtained after 2 to 4 weeks) from the patient’s clinical isolate. In order to provide the clinician with valuable information about the isolated mycobacteria leading to patient adapted therapy before bacteriological DST results are available, resistance is predicted by detection of mutations in certain genes of the mycobacteria. It is common practice for rifampicin (rpoB gene) and isoniazid (katG gene and/or inhA promoter region). In this MDR-TB collection, rifampicin resistant related mutations were found in 97.1% (168/173) of the clinical isolates and isoniazid resistant related mutations in 94.1% (160/170). The pncA, embB and gyrA genes have been sequenced to identify possible mutations because of their possible involvement with resistance to pyrazinamide, ethambutol and the fluoroquinolones respectively. However, little is known about the resistance prediction value of the mutations in these genes.<p>The study is also the first study on the molecular epidemiology of MDR-TB in the country. DNA fingerprinting showed a large diversity of strains (67% of the patients were infected by a strain with a unique pattern) and further epidemiological examination revealed limited local transmission of MDR-TB in Belgium.<p><p>The second part investigated the pncA gene and its association with pyrazinamide resistance in MDR-TB isolates from Belgium and in vitro cultured spontaneous mutants. The genetic analysis showed that 98.3% (59/60) of the Belgian clinical MDR pyrazinamide resistant (PZAR) isolates present a mutation in the pncA gene. We found 1.7% (1/60) of the PZAR MDR-isolates encoding wild type pncA and flank. A total (PZAR and PZAS) of 41 different amino acid changes, 3 protein truncations and 5 frameshifts were observed including eight novel mutations: 8Asp>Ala, 13Phe>Leu, 64Tyr>Ser, 107Glu>stop, 143Ala>Pro, 172Leu>Arg and frameshifts starting in codon 55 and 82. Analysis of all observed mutations (i.e. in clinical isolates as well as spontaneous mutants) revealed that they are not always associated with drug resistance and that they are not scattered randomly throughout the gene, but occur rather at preferential sites such as in codons with amino acids associated with either iron or substrate binding and catalytic active sites. The frequency of in vitro mutagenesis to pyrazinamide at pH 6.0 was determined and found to be relatively high at 10-5 CFU/ml.<p><p>Finally, the in vitro activity of tobramycin and clarithromycin (with unclear efficacy against M. tuberculosis) was evaluated on 25 M. tuberculosis clinical isolates with various resistance profiles. The effect of the drugs administered together was examined for possible synergistic effect. The median minimum inhibitory concentration (MIC) of 8 µg/ml obtained for both drugs in this study is rather high but are beyond the concentrations obtained in lung tissues. This suggests that both drugs should be investigated further as potential adjuncts to the treatment of resistant TB when other alternatives have failed; in particularly through new drug delivery systems such as the Dry Power Inhaler which allows local drug deposition with high drug concentrations in the lungs but low toxicity due to limited systemic absorption. In addition, for 36% of the tested isolates a decrease of the MIC of clarithromycin by a single or twofold dilution was observed in the presence of a subinhibitory concentration of tobramycin and no antagonistic effect was seen for the remaining isolates.<p><p>This research illustrates different (laboratory) aspects in the fight against drug resistant TB, all using the Belgian TB collection: characterisation of the Belgian MDR-TB situation on bacteriological, molecular and epidemiological level; profound analysis of genomic mutations and their possible association with drug resistance; and investigation of synergistic activity of drugs with low efficacy against M. tuberculosis.<p><br>Doctorat en Sciences biomédicales et pharmaceutiques<br>info:eu-repo/semantics/nonPublished

Emerging multidrug-resistant tuberculosis (MDR-TB) is one of the most urgent global public health issues. Recent advances in molecular techniques should enable the development of different rapid detection tests for drug-resistant TB. Large-scale comparative studies on the diagnostic accuracy and turn-around-time (TAT) of these novel assays may promote their smooth implementation as routine tests for TB in diagnostic laboratories. In a pilot evaluation of 30 clinical isolates and 202 sputum specimens, diagnostic performance of a novel in-house assay for MTB identification (IS6110 qPCR) was compared to a commercial COBAS TaqMan MTB test (Roche Diagnostics). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of IS6110 qPCR were 100%, 94.6%, 85.2% and 100%, respectively, compared to 94.7%, 100%, 100% and 98.6% for COBAS TaqMan MTB. Large-scale validation using 2,350 sputum specimens revealed the optimal cut-off crossing point (Cp) value of IS6110 qPCR was 29.61 with 97.3% sensitivity and 98.3% specificity determined by receiver operating characteristics (ROC) curve analysis. The median TAT for IS6110 qPCR and COBAS TaqMan MTB test to the reporting of results was 0.9 and 1.2 days, respectively. Among the IS6110 qPCR-positive specimens in the large-scale validation, 287 samples were tested in-house by katG MAS-PCR and rpoB PCR sequencing assays and 159 samples were tested by GenoType® MTBDRplus assay (Hain LifeScience). The sensitivity and specificity of katG MAS-PCR for isoniazid (INH) resistance detection were 71.4% and 99.5%, respectively. The sensitivity and specificity of rpoB PCR sequencing for rifampicin (RIF) resistance detection were 100% and 99.6%, respectively. Commercial GenoType® MTBDRplus assay reached 100% sensitivity for both INH and RIF resistance detection at a specificity of 99.3% and 100%, respectively. The median TAT for the in-house assays and GenoType® MTBDRplus assay to the reporting of the results was 4.7 and 1.4 days, respectively. The findings from this study provide different implementation strategies for diagnostic test combinations. The most cost-effective drug-resistant TB diagnosis cascade was IS6110 qPCR followed by GenoType® MTBDRplus assay. The TAT for results is 2.3 days at a cost of US$49.7. Despite an additional cost of US$24.6, COBAS TaqMan MTB test should replace IS6110 qPCR in populations with high prevalence of IS6110-negative strains. The in-house katG MAS-PCR and rpoB PCR sequencing assays should be used in developing countries instead of the expensive GenoType® MTBDRplus assay. Subsequently, accurate diagnosis of drug-resistant tuberculosis can be achieved in 4.5 days with a reasonable reagent cost of US$9.3. In conclusion, excellent diagnostic accuracy and shorter TAT of the molecular diagnostic cascade for drug-resistant TB, in particular IS6110 qPCR, can serve to guide physicians in the prompt choice of chemotherapy. This leads to timely delivery of anti-TB treatments to patients and holds the promise of easing the MDR-TB burden.<br>published_or_final_version<br>Microbiology<br>Master<br>Master of Philosophy

There were 8.6 million cases and 1.3 million deaths from tuberculosis (TB) globally in 2012. Among the major challenges to global TB control and the ultimate goal of TB elimination is the increasing prevalence of drug resistant strains of Mycobacterium tuberculosis worldwide, coupled with an extremely limited pipeline of novel drug development. In 2012 there were an estimated 450,000 cases of muti- drug resistant TB (resistant to at least rifampicin and isoniazid) and 170,000 deaths due to multi-drug resistant (MDR) TB worldwide. The prevalence of resistance to isoniazid is extrememly high In some regions of the world, including Vietnam, where 25% of new smear positive patients and 54% of re treatment patients are infected with strains resistant to isoniazid. Treatment outcomes are known to be worse for patients with undiagnosed isoniazid resistant (INHR) -TB treated with standard regimens but the majority of patients have successful outcomes. This thesis investigated risk factors for treatment failure among patients with isoniazid resistant TB in Ho Chi Minh City, Vietnam. Chapter one provides. an -introduction to tuberculosis and isoniazid resistant TB and chapter two describes the methodology of the studies decribed in the thesis. In chapter three, I investigate the treatment outcomes among a cohort of patients with isoniazid resistant tuberculosis treated according to National TB guidelines. The data show that unfavourable treatment outcomes are unacceptably high, at 19% among patients with INHR TB.

Thesis (M.Sc. (Medical Microbiology)) --University Limpopo, 2013<br>Genotyping of TB is essential to investigate and confirm transmission of the multi-drug resistant tuberculosis and of great value in optimizing strategies for the determination of strains causing the increased mortality rates of TB outbreaks. Sputum samples (207) were collected from National Health Laboratory Services in Polokwane laboratory for determining mutations and genotypes of the Mycobacterium tuberculosis strains using GenoType®MTBDRplus (Hain LifeScience, Germany) and Real-Time PCR (Roche, South Africa) techniques. Of the 207 samples, 28 (13.5%) exhibited drug resistance. Thirteen of the 28 (46%) MDR-TB strains belonged to the non-Beijing family, with mutations at codons rpoB 516 and rpoB 526 for RIF and katG 315 and inhA 15 for INH resistance. The Non-Beijing strains 75% (21/28) were monoresistant to RIF 14% (3/21) at codons 516, 526, 531 of rpoB gene and INH 19% (4/21) at codon 315 of katG and codon 15 of inhA 5% (1/21). Of the eight Beijing strains, 3(8%) were INH- resistant at codon 315 for katG and codon 15 for inhA and 3(8%) were RIF-resistant with mutations at codons 516 and 526. Two samples were typed as MDR for the Beijing strains with codon 315 for INH and codons 526 and 531 for RIF. The sample with a co-infection for Beijing and non-Beijing was an MDR-TB strain with mutations in rpoB codons 526, 531, katG 315 and inhA 8, 15 and16. The study showed a high rate of drug resistance with the non-Beijing compared to Beijing strains and mutations in specific codons for RIF and INH are variable for the TB families.

Objectives: We aimed to assess the variation in patient body weight over time according to the treatment outcome among multidrug-resistant tuberculosis (MDR-TB) cases. Methods: This was a retrospective cohort study. The data of patients commencing MDR-TB therapy were analyzed. Data were collected from different public TB treatment facilities located in peri-urban areas to the south of Lima, Peru. The outcome was patient body weight (kilograms) from treatment commencement, measured monthly. A random effects model was fitted using robust standard errors to calculate 95% confidence intervals. Results: Of a total of 1242 TB cases, 243 (19.6%) were MDR-TB. Only 201 cases were included in the analysis; 127 (63.2%) were males and the mean patient age was 33.6 (standard deviation 16.2) years. Weight changes over time among the patients who were cured differed from changes in those who died during therapy (p < 0.001). Weight curve divergence was important at the end of the third, fourth, and fifth treatment months: on average, the weight difference was 2.18 kg (p < 0.001), 3.27 kg (p = 0.007), and 3.58 kg (p = 0.03), respectively, when cured patients were compared to those who died. Conclusions: Our results show that weight variation during treatment can be a useful surrogate for the treatment outcome, specifically death during therapy. MDR-TB patients with weight loss should be followed more closely, as they are at greater risk of death.<br>Revisión por pares

Thesis (PhD)--Stellenbosch University, 2000.<br>ENGLISH ABSTRACT: Drug-resistant tuberculosis poses a threat to global tuberculosis control by the WHO DOTS strategy. Studies in the United States and Europe have shown (i) that drug-resistant tuberculosis is present in every country; (ii) that, by contrast to previous dogma, drug-resistant bacilli are virulent and can be transmitted, especially in institutional settings and to immunocompromised patients; and (iii) that the majority of cases arise by acquisition of drug resistance due to errors in the management of TB cases. (iv) Furthermore, it has been shown that the extremely high case fatality rates of the 1980s and early 1990s can be reduced by individualized, but costly treatment. However, the majority of drug-resistant TB cases reside in the developing world. Data on disease epidemics in less developed parts of the world are scarce. The aim of this thesis was to study the disease dynamics of drug-resistant TB in a developing country where TB is endemic. All cases of drug-resistant TB during a 5-year period in two communities with poor socioeconomic living conditions were included for this observational study. Three different methods were used: restriction fragment length polymorphism (RFLP), mutation detection analysis by dot-blot hybridisation technique and a Geographic Information System. Results of RFLP analysis and mutation detection analysis showed that community outbreaks of drug-resistant Mycobacterium tuberculosis strains occur, even without the involvement of immunocomprimised patients. Infection with a drug-resistant strain occurred in new patients (primary drug resistance) as well as in patients treated before (exogenous reinfection). Exogenous reinfection was also shown to be an important mechanism of recurrence after previous cure for drug-sensitive TB. Transmission of drug-resistant strains occurred more frequent in areas with lower socioeconomic living conditions. The relative contribution of transmission differed substantially between the group of multi drugresistant (two thirds of cases) and single-drug-resistant (no cases) cases, which probably reflects the prolonged infectiousness of multi drug-resistant cases. To stop the growing epidemic of multi drug-resistant TB, prevention of acquisition as well as transmission of drug-resistant tuberculosis will be required. This will only be possible in areas where a DOTS strategy is well functioning and with a modification of central elements of the standard DOTS mechanism: a "DOTS-plus" strategy. Early and accurate diagnosis of drug resistance is essential for effective management. Diagnosis based on two direct smear tests might have to be replaced by routine drugsusceptibility tests at diagnosis. Because the routine performance of phenotypic drugsusceptibility tests was inferior to the performance of genotypic tests, the development of an affordable commercial kit testing a limited number of mutations conferring resistance could be of great value in the global fight against multidrugresistant TB. Because of the importance of early diagnosis, selective active contact tracing for multidrug-resistant cases, additional to the routine passive contact tracing, could prove to be cost-effective. Individualized treatment regimens are effective in reducing the failure rate, mortality and probably transmission of multidrug-resistant TB. Multidrug-resistant tuberculosis is a problem confronting the efforts for global tuberculosis control. Efficient strategies to turn the tide exist, but international political commitment and financial support will be essential.<br>AFRIKAANSE OPSOMMING: Middel weerstandige tuberkulose hou 'n bedreiging in vir globale tuberkulose kontrole deur die WGO DOTS strategie. Studies in die Verenigde State en Europa het getoon (i) dat middel weerstandige tuberkulose in alle lande voorkom; (ii) dat, in teenstelling met vorige dogma, middel weerstandige bakterieë virulent is en oorgedra kan word, veral in inrigtings en aan immuun-onderdrukte pasiënte; en (iii) dat die meeste gevalle ontstaan deur die verwerwing van middel weerstandigheid a.g.v. die foutiewe hantering van tuberkulose gevalle. (iv) Bykomend is getoon dat die ontsettende hoë mortaliteit syfers van die 1980s verlaag kan word deur geindividualiseerde, maar duur behandeling. Die meeste middel weerstandige tuberkulose gevalle woon egter in die ontwikkelende wêreld. Data oor siekte epidemies in minder ontwikkelde dele van die wêreld is skaars. Die doel van hierdie tesis was om die siekte dinamiek van middel weerstandige tuberkulose te bestudeer in 'n ontwikkelende land waar tuberkulose endemies is. Alle gevalle van middel weerstandige tuberkulose gedurende 'n 5-jaar periode in twee lae sosio-ekonomiese gemeenskappe, is in hierdie studie ingesluit. Drie verskillende metodes is gebruik: restriksie fragment lengte polimorfisme (RFLP), mutasie analise deur dot-blot hibridisasie en 'n Geografiese Inligting Stelsel. Resultate van die RFLP analise het getoon dat uitbrake van middel weerstandige Mycobacterium tuberculosis stamme in die gemeenskap voorkom, selfs sonder die aantasting van immuun-onderdrukte pasiënte. Infeksie met middel weerstandige stamme het voorgekom in nuwe pasiënte (primêre middel weerstandigheid) en ook in pasiënte wat reeds voorheen behandel is (eksogene herinfeksie ). Daar is ook gevind dat eksogene herinfeksie 'n belangrike meganisme was van herhaalde tuberkulose na vorige genesing van middel sensitiewe tuberkulose. Die oordrag van middel weerstandige stamme het meer dikwels voorgekom in areas met laer sosioekonomiese omstandighede. Die relatiewe bydrae van oordrag het merkwaardig verskil tussen multi-middel weerstandigheid (twee derdes van gevalle) en enkelmiddel weerstandigheid (geen gevalle). Dit weerspieël waarskynlik die verlengde periode van infektiwiteit van die multi-middel weerstandige gevalle. Die bekamping van die groeiende epidemie van multi-middel weerstandige tuberkulose, vereis die voorkoming van verworwe sowel as oorgedraagde middel weerstandige tuberkulose. Dit sal slegs moontlik wees in areas waar 'n DOTS strategie reeds goed funksioneer en met 'n aanpassing van die sentrale elemente van die roetine DOTS meganisme: 'n "DOTS-plus" strategie. Vroeë en akkurate diagnose van middel weerstandigheid is essensieël vir effektiewe hantering. Diagnose gebaseer op twee direkte sputum smeer toetse mag moontlik vervang moet word deur roetine middel sensitiwiteit bepalings by diagnose. Die roetine fenotipiese middel sensitiwiteit bepaling is gevind om minderwaardig te wees in vergelyking met die genotipiese toetse. Die ontwikkeling van 'n bekostigbare toetsstelsel wat die mees algemene mutasies vir middel weerstandigheid sal opspoor, kan van groot waarde wees in die stryd teen mutimiddel weerstandige tuberkulose. Aangesien vroeë diagnose so belangrik is, kan aktiewe kontak opsporing koste-effektief wees. Ge-individualiseerde behandelingskedules is effektief om die sukses van behandeling en oorlewing te verbeter, en moontlik ook om die oordrag van multi-middel weerstandige tuberkulose te verminder. Multi-middel weerstandige tuberkulose is 'n probleem vir die globale kontrole van tuberkulose. Effektiewe strategieë om die vloed te stuit, bestaan, maar politieke verbintenis en geldelike ondersteuning sal essensieël wees.

<p>Many studies have reported low cure rates for multidrug-resistant tuberculosis (MDRTB) patients and MDR-TB patients co-infected with human immunodeficiency virus (HIV). However, little is&nbsp<br>known about the effect of HIV infection and antiretroviral therapy on the treatment outcomes of MDR-TB in South Africa. Therefore, the objectives of the study are: to find out whether HIV infection&nbsp<br>and interactions between ARVs and second line anti-TB drugs have an impact on the following MDR-TB treatment outcomes: cure rate and treatment failure at Brewelskloof Hospital. MDR-TB&nbsp<br>patients were treated for 18-24 months. The study was designed as a case-control retrospective study comparing MDR-TB treatment outcomes between HIV positive (cases) and HIV negative&nbsp<br>patients (controls). Patients were included in the study only if they complied with the following criteria: sensitivity to second line anti-TB drugs, MDR-TB infection, co-infection with HIV (for some&nbsp<br>of them), male and female patients, completion of treatment between 1 January 2006 and 31 December 2008. Any patients that presented with extreme drug-resistant tuberculosis (XDR-TB)&nbsp<br>were excluded from the study. Data were retrospectively collected from each patient&rsquo<br>s medical records. There were a total of 336 patients of which 242 (72%) were MDR-TB patients and 94&nbsp<br>(27.9%) MDRTB co-infected with HIV patients. Out of the 242 MDR-TB patients, 167 (69.2%) were males and 75 (30.7%) were females. Of the 94 patients with MDR-TB co-infected with HIV, 51&nbsp<br>(54.2%) males and 43 (45.7%) females. Patients with multidrug-resistant tuberculosis co-infected with HIV who qualify for antiretroviral therapy were treated with stavudine, lamivudine and&nbsp<br>efavirenz while all MDR-TB patients were given kanamycin, ethionamide, ofloxacin, cycloserine and pyrazinamide. The cure rate of MDR-TB in HIV (+) patients and in HIV (-) patients is 34.5%&nbsp<br>and 30 % respectively. There is no significant difference between both artes (pvalue = 0.80). The MDR-TB cure rate in HIV (+) patients taking antiretroviral drugs and in HIV (+) patients without&nbsp<br>antiretroviral therapy is 35% and 33% respectively. The difference between both rates is not statistically significant. The study shows that 65 (28.0%) patients completed MDR-TB treatment but&nbsp<br>could not be classified as cured or failure, 29 (12.5%) patients failed, 76 (32.7%) defaulted, 18 (7.7%) were transferred out and 44 (18.9%) died. As far as treatment completed and defaulted is concerned,&nbsp<br>there is no significant statistical difference between HIV (+) and HIV (-) The number of patients who failed the MDR-TB treatment and who were transferred out is significantly higher in the HIV (-)&nbsp<br>group than in the HIV (+) group. Finally the number of MDR-TB patients who died is significantly higher in the HIV (+) group). The median (range) duration of antiretroviral therapy before starting&nbsp<br>anti-tuberculosis drugs is 10.5 (1-60) months. According to this study results, the MDR-TB treatment cure rate at Brewelkloof hospital is similar to the cure rate at the national level. The study also&nbsp<br>hows that HIV infection and antiretroviral drugs do not influence any influence on MDR-TB treatment outcomes.</p>

Tuberculosis (TB) is a leading public health problem across the world. For various reasons, TB and multidrug-resistant tuberculosis (MDR-TB) have increased. Clarification on TB/HIV co-infection and homelessness as risk factors for TB and MDR-TB is required to inform policy interventions to reduce TB-related morbidity, mortality, and healthcare costs. In this quantitative study, data from the Houston Health Department (N = 341) were analyzed to explore the relationship between TB and MDR-TB outcomes and TB/HIV co-infection and type of housing/homelessness. Foreign-born persons are disproportionately affected in the United States. The socio-ecological model provided a theoretical framework for the investigation. Multiple and logistic regression analyses were conducted to investigate the relationships between variables, controlling for age and gender. Results indicate that HIV infected persons were more likely than non-infected persons to contract TB, and homeless persons were more likely than non-homeless persons to contract TB/MDR-TB, suggesting that high TB/HIV co-infection rates increase prevalence of TB and MDR-TB while improvements in housing reduce prevalence of TB and MDR-TB. However, no significant associations between variables were found. The odds ratio, Exp(B) = 0.000, p -?¥ 0.90, 95% Cl [0.000, with no upper bound values] was observed for both independent variables. Regular screening for TB/HIV co-infection among persons with high TB and MDR-TB risk profiles is recommended. Further investigation is required. Inclusion of more covariates could further elucidate more evidence of an association between variables. Study findings may support interventions to reduce TB-related morbidity, leading to positive social change.

ABSTRACT INTRODUCTION: Multi-drug resistant tuberculosis (MDR-TB) poses a great threat to the eradication of TB. In the US, MDR-TB is faced with inadequate diagnostic tools and long and expensive treatment regimens. Therefore, preventing the disease is the key to saving lives and resources. Social and behavioral variables play a big part in this prevention. It is important to determine the social factors that may lead to MDR-TB in order to set up prevention programs and more efficient treatment regimens. AIM: This study was conducted to ascertain the social determinants of MDR-TB in the US between the years of 2005 and 2009 to better equip public health officials to deal with this growing threat. METHODS: This study used the Centers for Disease Control and Prevention (CDC) Online Tuberculosis Information System (OTIS) database to find associations between certain social variables and MDR-TB. The variables that were tested were whether or not the individual had lived in a correctional facility for the past year; HIV status; homelessness; whether or not the individual had an occupation; and whether the individual was foreign-born or US-born. An unadjusted odds ratio (OR) was calculated to find this association. The variables were then stratified with age; sex; race; age and race; age and sex; and age, sex, and race to see whether or not the strata were confounders. RESULTS: The variables of having lived in a correctional facility and homelessness were found to be associated with MDR-TB. However, all of the strata were found to be confounders for this relationship. Having HIV and being US-born were not found to be associated with MDR-TB. All of the strata for HIV were found to be confounders. But for place of birth, stratifying by age, sex, and both age and sex were not confounders. The rest of the strata were. The OR for occupation versus MDR-TB was almost at 1, meaning that those with a job and those without a job had almost equal odds of having MDR-TB. Effect modification was present for the strata in all variables, meaning that the risk of having MDR-TB varied with each different age, sex, and racial group. DISCUSSION: Results from this study showed which variables were more likely to be associated with MDR-TB in the US between the years of 2005 and 2009. However, when compared to the literature that exists, the results showed that more research needs to be done to properly ascertain this relationship. Using this study, public health officials can identify which populations to focus prevention efforts on.

Rationale. In Quebec, 6.2% of all Mycobacterium tuberculosis (TB) isolates from Canadian-born patients are resistant to pyrazinamide alone (mono-PZA-R). Over 90% of mono-PZA-R isolates in Quebec have been characterized by a specific and unique mutation in the pncA gene. The unusually high prevalence of mono-PZA-R disease and its associated mutational profile in Quebec provided an exceptional opportunity to study the epidemiologic and clinical significance of mono-PZA-resistance in patients with active TB. Methods. 67 patients with mono-PZA-R TB diagnosed between 1 Jan 1990 and 31 Dec 2000 were compared to 211 randomly selected patients with pan-sensitive (Pan-S) isolates diagnosed within the same time period. Demographic, laboratory, and clinical information pertaining to patients diagnosed with TB from the provincial database of Maladies a declarations obligatoires (MADO) were linked to drug resistance profiles derived from the provincial laboratory. Data from MADO were supplemented by other clinical information abstracted from chart review, the provincial drug insurance database, and the provincial registry for Bacillus Calmette Guerin vaccination. Results. There were no statistically significant differences in demographics or clinical characteristics between patients infected with mono-PZA-R compared to Pan-S strains. Among patients with mono-PZA-R TB, 51 (76%) were cured, 3 (4%) relapsed, and 13 (19%) died within 6 months of diagnosis. In comparison, for subjects with Pan-S TB, 181 (86%) were cured, 2 (1%) relapsed, 2 (1%) failed treatment, and 26 (12%) died within 6 months of diagnosis. In multivariate logistic regression analysis, mono-PZA-R was associated with decreased odds of successful clinical outcomes compared with Pan-S TB (OR=0.38, 95% CI = 0.18-0.81). Conclusion. PZA-resistance had a clinically significant impact on outcome of TB disease.

Thesis (MD)--University of Stellenbosch, 2002.<br>ENGLISH ABSTRACT: Resistance to antituberculosis agents became evident soon after antituberculosis treatment was introduced for the first time. Combined drug therapy seemed to resolve this problem. Animal experimental studies, which showed that isoniazid (INH)-resistant strains of Mycobacterium tuberculosis were less infectious and pathogenic than drugsusceptible strains, gave further reassurance that drug resistance was not a major issue. Transmission of INH- and multiple-drug-resistant strains did, however, occur. Studies in children, who develop mainly primary drug resistant tuberculosis (TB), showed that drug resistance in adults was followed by a similar rise in drug-resistant (TB) in children, and that tuberculous infection rates in childhood contacts of INHresistant and drug-susceptible adult TB cases were the same. It was however, only after the significant rise in the incidence of TB and large outbreaks of multidrug-resistant (MDR) TB cases in developed countries (mainly because of the human immunodeficiency virus epidemic) in the early nineties that sufficient attention was again focussed on the problem of drug-resistant TB. Drugresistant tuberculosis, and more in particular MDR TB, posed a serious threat to global TB control programmes. Despite this renewed interest, childhood drug-resistant TB remained neglected. The incidence of drug-resistant TB among children, which could give a good indication of currently circulating strains in a community, is hardly known. The management of childhood contacts of adults with infectious MDR TB or children with MDR TB has also not been studied prospectively. All confirmed childhood TB cases from a specific geographic drainage area over a 3.5-year period were prospectively included in a drug resistance surveillance study. The incidence of drug resistance in children was comparable to the incidence of initial (primary plus undisclosed previous treatment) drug resistance documented in adults in the same area. The findings show that the incidence of drug-resistant TB in children in the Western Cape province is low, and probably reflects the level of primary drug resistance amongst organisms currently circulating in this community. The short- and long-term outcome of children <5 years of age in contact with infectious adult MDR TB cases was determined by prospective follow-up for 30 months. The initial evaluation showed an infection rate significantly higher in MDR TB contacts compared with contacts of drug susceptible cases, but the disease rate was lower. On follow-up, many more children became infected or developed disease. The finding that 90% of those who developed disease did so within the first 12 months, indicates that follow-up beyond 12 months is probably not cost-effective in resource poor countries. The results demonstrate that MDR TB is not less infectious than drug susceptible TB. Despite the fact that some children received chemoprophylaxis, 24% of the children eventually developed disease. This is not different from the expected prevalence of disease in childhood contacts <5 years of age of infectious drug-susceptible adult pulmonary TB cases. Restriction fragment length polymorphism analysis confirmed transmission from an adult source case to a child contact in 5 of 6 adult-child pairs in whom both isolates were available. If therefore an isolate of M tuberculosis for susceptibility testing cannot be obtained from a child in close contact with an infectious MDR TB case, the child should therefore be treated according to the drug susceptibility pattern of the source case's strain. Treatment of children with confirmed and probable MDR TB included 2 or 3 drugs to which the adult source case's isolate was susceptible in addition to pyrazinamide and high-dose INH. Duration of treatment ranged from 6 to 12 months depending on the severity of the disease. INH was included in the treatment regimen because low-level resistance to INH was present in about half the cases of primary INH resistance. The pharmacokinetics of INH in children confirmed that an adequate concentration and exposure time could be achieved for this purpose. Ethionamide often caused gastrointestinal adverse events, but these could be overcome in most cases by temporary dose adjustments. The fluoroquinolones, which are not generally recommended for use in children, possibly caused arthralgia in 1 of the17 children treated for ~6 months. This is in accordance with previous reports of the safety of these drugs in children for short- and medium-term treatment. TB disease occurred significantly less often in children who received appropriate chemoprophylaxis (according to the drug susceptibility pattern of the adult source case's isolate). Although this was not a randomised controlled trial, the group that received chemoprophylaxis was at higher risk for developing disease. This implies that prevention of TB in MDR contacts is possible. A prospective, randomised controlled study is necessary to evaluate the best drug combinations and the optimal duration of such chemoprophylactic regimens.<br>AFRIKAANSE OPSOMMING: Middelweerstandigheid het na vore gekom kort nadat antituberkulose behandeling vir die eerste keer in gebruik geneem is. Die gekombineerde gebruik van middels het klaarblyklik die probleem oorkom. Diere eksperimente wat getoon het dat isoniasied (INH)-weerstandige stamme van Mycobacterium tuberculosis minder infektief en patogenies IS as vatbare stamme, het verdere gerustelling gegee dat middelweerstandigheid nie 'n groot probleem is nie. Die oordrag van INH- en multi-middelweerstandige stamme het egter wel plaasgevind. Studies in kinders, wat hoofsaaklik primêre middelweerstandige tuberkulose (TB) ontwikkel, het getoon dat middelweerstandigheid in volwassenes gevolg is deur 'n soortgelyke toename in middelweerstandige TB in kinders en dat die voorkoms van tuberkuleuse infeksie in kinderkontakte van INH-weerstandige en middelvatbare volwasse TB gevalle dieselfde is. Dis egter eers toe daar 'n beduidende toename in die insidensie van TB en groot uitbrake van multimiddelweerstandige (MDR) TB gevalle in die ontwikkelde lande (hoofsaaklik as gevolg van die menslike immuungebrek virus epidemie) in die vroeë negentigerjare was dat daar opnuut aandag aan die probleem van weerstandige TB geskenk is. Middelweerstandige TB, en in besonder MDR TB, hou 'n ernstige bedreiging vir globale TB beheerprogramme in. Tenspyte van die nuwe belangstelling in middelweerstandige TB is die probleem in kinders steeds afgeskeep. Die insidensie van weerstandige TB in kinders is onbekend alhoewel dit 'n goeie weergawe van die huidig sirkuIerende stamme in 'n gemeenskap sou gee. Die hantering van kinderkontakte van volwassenes met infektiewe MDR TB of kinders met MDR TB is ook nog nie prospektiefbestudeer nie. Alle bevestigde kinder-TB gevalle van 'n spesifieke geografiese gebied is oor 'n 3.5 jaar tydperk prospektief in 'n middelweerstandige waarnemingstudie ingesluit. Die insidensie van middelweerstandigheid in kinders was vergelykbaar met die insidensie van inisiële (primêre weerstandigheid plus onbekende vonge behandeling) middelweerstandigheid in volwassenes van dieselfde gebied. Die bevindinge toon dat die insidensie van middelweerstandige TB in kinders in die Weskaap provinsie laag is. Dit weerspieël waarskynlik die vlak van primêre middelweerstandigheid in organismes wat tans in hierdie gemeenskap sirkuleer. Die kort- en langtermyn uitkoms van kinders <5 jaar oud wat in kontak met infektiewe volwasse MDR TB gevalle was, is prospektief tydens 'n 30-maande opvolg bepaal. Die aanvanklike evaluasie het 'n beduidend hoër infeksiekoers in die MDR TB kontakte in vergelyking met kontakte van middelvatbare gevalle getoon, maar die siektekoers was laer. Tydens die opvolgperiode het baie meer kinders infeksie of siekte ontwikkel. Aangesien 90% van dié wat siekte ontwikkel het, dit gekry het binne die eerste 12 maande, is opvolg ná 12 maande waarskynlik nie koste-effektief in hulpbronbeperkte lande nie. Die bevindinge toon dat MDR TB nie minder infektief is as middelvatbare TB nie. Tenspyte daarvan dat sommige kinders chemoprofilakse ontvang het, het 24% van die kinders uiteindelik siekte ontwikkel. Dit verskil nie van die verwagte siekte-insidensie van kinderkontakte <5 jaar oud wat in kontak met infektiewe volwasse middelvatbare pulmonale TB was nie. Restriksie fragment lengte polimorfisme analise het oordrag van volwasse brongeval na kinderkontak in 5 uit 6 volwasse-kind pare, van wie beide isolate beskikbaar was, bevestig. Indien daar dus nie 'n isolaat van M. tuberculosis vir vatbaarheidstoetse van 'n kind met nabye kontak met 'n infektiewe MDR TB geval beskikbaar is nie, behoort die kind volgens die middelvatbaarheidspatroon van die brongeval se stam behandel te word. Behandeling van kinders met bevestigde of waarskynlike MDR TB het 2 tot 3 middels waarvoor die volwasse brongeval se isolaat vatbaar was, ingesluit, tesame met pirasinamied en hoë-dosis INH. Die duur van behandeling het gewissel van 6 tot 12 maande op grond van die omvang van die siekte. INH is in die behandeling ingesluit omdat dit getoon is dat ongeveer die helfte van die gevalle met primêre INHweerstandigheid lae-vlak weerstandigheid het. Die farmakokinetika van INH in kinders het bevestig dat genoegsame vlakke en blootstellingstyd aan INH vir hierdie doel bereik kan word. Etionamied het dikwels gastrointestinale newe-effekte veroorsaak, maar dit kon in die meeste gevalle oorkom word. Die fluorokwinolone, wat nie oor die algemeen in kinders aanbeveel word nie, het moontlik artralgie veroorsaak in 1 uit 17 kinders wat vir ~6 maande behandel is, wat vorige verslae oor die veiligheid van hierdie middels in kort- en medium-termyn behandeling bevestig. TB-siekte het beduidend minder dikwels voorgekom in kinders wat toepaslike chemoprofilakse (volgens die middelvatbaarheidspatroon van die volwasse brongeval se isolaat) ontvang het. Alhoewel dit nie 'n ewekansig gekontroleerde studie was nie, het die groep wat chemoprofilakse ontvang het die hoogste risiko vir die ontwikkeling van siekte gehad. Dit dui daarop dat voorkoming van TB in MDR TB kontakte moonlik is. 'n Prospektiewe, ewekansig gekontrolleerde studie is nodig om die beste middel kombinasies en die optimale duur van so 'n chemoprofilaktiese behandeling te bepaal.

Thesis (MScMedSc)--Stellenbosch University, 2013.<br>ENGLISH ABSTRACT: Multidrug resistant tuberculosis (MDR-TB), defined as having resistance to at least the first-line drugs, isoniazid and rifampicin (RIF), is a global health problem. Mutations in the rpoB gene, encoding the β-subunit of RNA polymerase, are implicated in RIF resistance - with the S531L and H526Y mutations occurring most frequently. The level of RIF resistance varies for strains with identical rpoB mutations, which suggests that other factors play a role in RIF resistance. Efflux has been implicated in determining the intrinsic level of RIF resistance. Increased expression of the multidrug efflux pump, Rv1258c, following RIF exposure was observed in some Mycobacterium tuberculosis MDR clinical isolates and H37Rv RIF mono-resistant mutants, but not others. The factors influencing the induction of Rv1258c are poorly understood. The aim of this study was to investigate the effects of rpoB mutations on expression of Rv1258c and whiB7, a transcriptional regulator of Rv1258c, in M. tuberculosis H37Rv in vitro generated RIF resistant mutants, in the absence and presence of RIF. The promoter region of M. tuberculosis H37Rv Rv1258c was cloned into a position upstream of a lacZ gene (encoding β-galactosidase) in multi-copy episomal and integrating vectors. Vector functioning and the effect of rpoB mutations on Rv1258c promoter activity were initially investigated in the non-pathogenic related species, Mycobacterium smegmatis mc2155 rpoB mutants and subsequently in M. tuberculosis by doing β-galactosidase assays. qRT-PCR was done to investigate the effects of rpoB mutations on native Rv1258c and whiB7 gene expression. Episomal and integrating vectors were functional and the integrating vector system was used for subsequent β-galactosidase assays in M. tuberculosis. Rv1258c promoter activity in the S531L mutant was approximately 1.5 times less and in the H526Y mutant 1.5 times higher than that of the wild-type in M. smegmatis. Similarly, Rv1258c promoter activity in the S531L mutant was approximately half and in the H526Y mutant approximately double that of the wild-type in M. tuberculosis. A similar trend in Rv1258c and whiB7 expression to those observed using β-galactosidase assays were observed when investigating the native Rv1258c and whiB7 gene transcript levels compared to the wild-type using qRT-PCR, although differences were not significant. Exposure of the M. smegmatis and M. tuberculosis rpoB mutants to sub-inhibitory levels of RIF did not affect Rv1258c promoter activity. Mutations in rpoB had a marginal effect on Rv1258c and whiB7 transcript levels, but showed the same trend as that seen for Rv1258c promoter activity. It remains to be determined whether these differences are biologically significant. When considering efflux pumps as new targets for treatment, possible differences in efflux pumps expression due to different rpoB mutations should be considered.<br>AFRIKAANSE OPSOMMING: Multi-middel weerstandige tuberkulose (MDR-TB) word gedefinieer as weerstandigheid tot ten minste rifampisien (RIF) en isoniasied, wat deel van die eerstelyn anti-tuberkulose behandeling vorm. Mutasies in die rpoB geen, wat die β-subeenheid van die RNA polimerase enkodeer, word geassosieer met RIF weerstandigheid. S531L en H526Y rpoB mutasies kom die algemeenste voor. RIF weerstandigheids vlakke verskil egter tussen isolate met identiese rpoB mutasies, wat impliseer dat ander faktore ook 'n rol in RIF weerstandigheid speel. 'n Toename in transkripsie van die Rv1258c geen, wat 'n multi-middel effluks pomp enkodeer, is waargeneem met blootstelling aan RIF, slegs in sommige M. tuberculosis H37Rv RIF mono-weerstandige mutante and MDR kliniese isolate, maar nie in ander nie. Die faktore wat die induksie van die Rv1258c effluks pomp beïnvloed is nie goed nagevors nie. Die studie ondersoek die effek van die rpoB mutasies op die uitdrukking van die Rv1258c en whiB7,'n transkripsionele regulator van Rv1258c, gene in M. tuberculosis H37Rv in vitro gegenereerde RIF weerstandige mutante, in die teenwoordigheid en afwesigheid van RIF. Die promotor area van die M. tuberculosis H37Rv Rv1258c geen is in 'n posisie stroomop van 'n lacZ geen, wat vir β-galaktosidase enkodeer, in multi-kopie episomale en integreerende vektors ingekloneer. Die funksionaliteit van die vektor en effek van rpoB mutasies op Rv1258c promotor aktiwiteit is ondersoek in die naverwante nie-patogeniese spesies, M. smegmatis en daarna in M. tuberculosis deur β-galaktosidase essais te doen. qRT-PCR is gedoen om die effek van rpoB mutasies op die vlak van transkripsie van die natuurlike Rv1258c geen en die whiB7 geen te bestudeer. Beide die episomale en integreerende vektors was funksioneel en daar is besluit om die integreerende vektor vir daaropeenvolgende β-galaktosidase essais in M. tuberculosis te gebruik. Rv1258c promotor aktiwiteit van die S531L mutant was ongeveer 1.5 keer minder as en die van die H526Y mutant 1.5 keer hoër as die van die ongemuteerde bakterië in M. smegmatis. Soortgelyk was die Rv1258c promoter aktiwiteit van die S531L mutant ongeveer die helfde van en die van H526Y mutant ongeveer dubbel die van die ongemuteerde bakterië in M. tuberculosis 'n Soortgelyke neiging in die vlakke van Rv1258c en whiB7 transkripte van die natuurlike geen is gedurende qRT-PCR waargeneem alhoewel die verskille nie beduidend was nie. Blootstelling aan sub-inhibitoriese konsentrasies van RIF het geen effek op Rv1258c uitdrukking in die M. smegmatis of M. tuberculosis rpoB mutante gehad nie. Die rpoB mutasies het net 'n effense effek op Rv1258c en whiB7 transkrip vlakke in M. tuberculosis rpoB mutante, maar transkrip vlakke het 'n soortgelyke neiging as die Rv1258c promoter aktiwiteit getoon. Of die waargenome verskille biologies betekenisvol is, moet nog bepaal word. Indien effluks pompe as teikens vir bahandeling gebruik sou word, moet in ag geneem word dat effluks pompe moontlik verskillend uitgedruk word in verskillende rpoB mutante.<br>The DST/NRF Centre of Excellence in Biomedical Tuberculosis Research, Stellenbosch University<br>DAAD-NRF in Country Scholarship and Ernst and Ethel Eriksen Trust<br>Harry Crossley Foundation

Multi-drug resistant tuberculosis is a major global health problem. Viet Nam is 14th among 27 MDR-TB high burden countries with an estimated about 5,100 MDR-TB cases among notified TB cases per year. Management of MDR-TB in Viet Nam is one of the main objectives of the TB control programme. This thesis provides an understanding of the current situation of MDRlXDR-TB in Vietnam and its control policies focusing on case finding strategy, targeting groups for MDR-TB screening. MDR-TB contacts, one of the high risk groups recommended by the WHO is a focus of this thesis. The thesis presents screening practices of household contacts of TB patients, feasibility of TB contact investigations, and to identify challenges and solutions for a successful implementation of an efficient contact investigation among MDR -TB patients in Viet Nam. Since 2009, the programmatic management of drug resistant tuberculosis (PMDT) was piloted in Viet Nam following the development of 2009 country MDR TB guideline. A year after the WHO updated guideline was disseminated, the country revised its guideline and SOP to be in line with WHO's recommendations and contextualized to local capacity and resources. The PMDT has been rolled out and scaled up in the country. However, lack of resources, limited communication on policy changes to lower level, unable to provide screening to all risk groups, inadequate capacity to perform diagnosis of mono and poly resistant TB and second- line DST have posed significant challenges for the NTP to implement their policy. This study found that only about 30 % MDR TB cases was detected. through the PMDT system. The possible reasons we identified were: (1) delay in fully rolling out PMDT policies and limited capacity of the system, mostly due to inadequate resources, (2) operational factors, . . and (3) neglecting high risk groups during MDR- TB screening, particularly close contacts of MDR TB patients. Noteworthy, the NTP strategy relies on "passive case finding" while the proportion of household contacts of smear-positive tuberculosis patients screened for TB under the current passive screening approach of the Vietnam National TB program is very low compared with prevalence of TB among contacts in high burden countries, particularly for contacts under 5 years of age. Although screening of close contacts of MDR-TB patients is recommended by the NTP of Viet Nam, this is generally not done.

INTRODUÇÃO: A incidência de tuberculose (TB) em Santos (SP) situa-se em 73/100.000 habitantes-ano. A prevalência média de coinfecção TB/HIV é de 16%, taxas de cura e abandono de tratamento, entre casos novos são, respectivamente, 71% e 12%. Tais indicadores sugerem elevado risco para TB multidroga resistente (TBMR) no município, com incidência estimada em 1,9/100.000 habitantes-ano. OBJETIVO: Descrever e analisar o perfil de sensibilidade às drogas (TS) de primeira e segunda linha de tratamento entre pacientes com TB pulmonar (TBP), estimar a incidência de TBMR e a proporção de TB extensivamente resistente (TBXR); analisar aspectos moleculares, epidemiológicos e institucionais dos casos de TBP resistentes em Santos (SP). MÉTODOS: Estudo descritivo de uma coorte de pacientes de TBP, com início de tratamento ou retratamento entre 01 de janeiro de 2011 a 31 de dezembro de 2012. Definiu-se como caso de TBP, indivíduos com 15 anos ou mais, de ambos os sexos, residentes no município de Santos, com manifestações clínicas compatíveis com TBP e confirmação por cultura com isolamento de Mycobacterium tuberculosis. As variáveis de interesse para o estudo foram as características sociodemográficas, história atual e pregressa de TB, aspectos relativos ao tratamento, co-morbidades, ao diagnóstico e resistência a drogas. Para as análises comparativas entre proporções foram usados os testes qui-quadrado de Pearson e o Exato de Fisher e para variáveis contínuas o teste T de Student ou o de Kruskal - Wallis. Os perfis genéticos dos isoladas resistentes a ao menos uma droga foram obtidos pela técnica RLFP e analisados pelo programa Bionumerics versão 5.0 (Applied Maths - Bélgica). A descrição da distribuição espacial da TB resistentes e clusters foram feitas mediante a inserção dos casos no mapa de Santos, por endereço de residência, segundo o índice de vulnerabilidade social. RESULTADOS: Dos 263 casos de TBP selecionados, 68,4% (180/263) eram do sexo masculino, a mediana da idade foi de 38 anos, 8,7% (23/263) eram diabéticos; 20,4% (42/206) dos casos novos apresentavam ao menos um fator de risco para TBMR; destacando-se entre estes casos 10,7% (22/206) de confecção HIV/TB; 47,3% (123/260) tiveram tratamento supervisionado, 14,7% (91/617) dos contatos foram examinados, 18,6% (49/263) foram hospitalizados durante o tratamento, perfazendo uma média de 145,4 dias por paciente. Entre os casos resistentes a ao menos uma droga, a resistência à isoniazida foi 8,4% (22/263) e à rifampicina 3,8% (10/263) dos casos. A TBMR primária foi encontrada em 1,9% (4/206) dos casos e destes 25,0% (1/4) eram TBXR. A incidência média anual de TBMR foi de 0,57/100,000 habitantes. Dos 25 isolados resistentes ao menos uma droga, submetidos à RFLP, 12 (48,0%) foram agrupados em seis grupos genéticos, com dois pacientes em cada grupo. CONCLUSÕES: A elevada proporção TBMR primária, com um caso de TBXR enfatizam a necessidade de universalizar a cultura e TS, ampliar a cobertura do tratamento supervisionado, a investigação rotineira dos contatos e o monitoramento da resistência a drogas. O fortalecimento da vigilância da resistência às drogas é indispensável para o contínuo aperfeiçoamento do Programa de Controle da TB, especialmente em regiões de elevada carga da doença<br>INTRODUCTION: The incidence of tuberculosis (TB) in Santos (SP) is located around 73 / 100,000-year, approximately double that found on average in the country. The average prevalence of TB / HIV is 16% cure rates and treatment dropout among new cases are, respectively, 71% and 12%. Such indicators suggest high risk for multidrug-resistant TB (MR-TB) in the city, with the incidence estimated at 1.9 / 100,000-year. OBJECTIVE: To describe and analyze the sensitivity to drugs of first and second line treatment of patients with pulmonary TB (PTB) to estimate the incidence of MR-TB and extensively drugresistant TB (TBXR), describe molecular and institutional aspects, spatial distribution, epidemiological PTB resistant cases in the city of Santos (SP). METHODS: A descriptive study of a cohort of patients with PTB residing in the city who started treatment or retreatment in the period January 2011 to December 31, 2012. The case definition PTB individuals 15 years or more, both sexes, living in the city of Santos (SP), who present clinical manifestations compatible with PTB and whose confirmation was made by culture with isolation of M. tuberculosis. The variables of interest for the study were: bacteriological / laboratory socio-demographic characteristics, current and previous history of TB, aspects related to treatment, and comorbidities. For comparative analyzes of proportions the chi-squared tests and Fisher\'s exact were used for continuous variables and the Student t test or the Kruskal - Wallis. The genetic profiles of isolates resistant to at least one drug were obtained by RFLP (length polymorphism restriction fragment) and analyzed using version BioNumerics 5.0 (Applied Maths - Belgium) software. The description of the spatial distribution of resistant TB and the clusters was made by inserting the cases in Santos map, by address of residence, which was according to the index of social vulnerability. RESULTS: Of the 263 cases of PTB selected, 68.4% (180/263) were male, th median age was 38 years, 8.7% (23/263) were diabetes; 20.4% (42/206) of new cases had at least one risk factor for MR-TB, especially 10.7% (22/206) of making HIV / TB; 47.3% (123/260) underwent supervised treatment, 14.7% (91/617) of the contacts were examined, 18.6% (49/263) were hospitalized during treatment, totaling 7127 days of hospitalization with a mean 145.4 days per patient. Among the cases resistant to at least one drug resistance to isoniazid 8.4% (22/263) and rifampin 3.8% (10/263) of the cases was found. The primary MR-TB was found in 1.9% (4/206) of MR-TB cases and of these 25.0% (1/4) were TBXR. The average annual incidence of MDR-TB was 0.57/100,000 inhabitants. Of the 25 isolates resistant least one drug, subjected to molecular characterization of IS6110, 12 (48.0%) were grouped in six clusters, with each group including two isolates. CONCLUSIONS: A high proportion of primary MR-TB, including a case of TBXR emphasizes the need to universalize culture and TS, expand the coverage of supervised treatment, routine investigation of contacts and monitoring of drug resistance. The strengthening of the surveillance of drug resistance is essential for continuous improvement of the TB Control Program, especially in regions of high disease burden

The tuberculosis epidemic is escalating in South Africa as well as globally. This escalation is exacerbated by the increasing prevalence of multidrug-resistant tuberculosis (MDRTB), which is defined by the World Health Organisation (WHO) as resistance of Mycobacteria to at least isoniazid and rifampicin. Multi-drug resistant tuberculosis is estimated to occur in 1-2% of newly diagnosed tuberculosis (TB) patients and in 4-8% of previously treated patients. MDRTB is both difficult and expensive to treat, costing up to 126 times that of drug-sensitive TB. Resource constrained countries such as South Africa often lack both the money and the infrastructure to treat this disease. The aim of this project was to determine whether the performance of a systematic review with subsequent economic modelling could influence the decision making process for policy makers. Data was gathered and an economic evaluation of MDRTB treatment was performed from the perspective of the South African Department of Health. Three treatment alternatives were identified: a protocol regimen of second line anti-tuberculosis agents, as recommended in the South African guidelines for MDRTB, an appropriate regimen designed for each patient according to the results of culture and drug susceptibility tests, and non-drug management. A decision-analysis model using DATA 3.0 by Treeage® was developed to estimate the costs of each alternative. Outcomes were measured in terms of cost alone as well as the ‘number of cases cured’ and the number of ‘years of life saved’ for patients dying, being cured or failing treatment. Drug, hospital and laboratory costs incurred using each alternative were included in the analysis. A sensitivity analysis was performed on all variables in order to identify threshold values that would change the outcome of the evaluation. Results of the decision analysis indicate that the individualised regimen was both the cheaper and more cost-effective regimen of the two active treatment options, and was estimated to cost R50 661 per case cured and R2 070 per year of life saved. The protocol regimen was estimated to cost R73 609 per case cured and R2 741 per year of life saved. The outcome of the decision analysis was sensitive to changes in some of the variables used to model the disease, particularly the daily cost of drugs, the length of time spent in hospital and the length of treatment received by those patients dying or failing treatment. This modelling exercise highlighted significant deficiencies in the quality of evidence on MDRTB management available to policy makers. Pragmatic choices based on operational and other logistic concerns may need to be reviewed when further information becomes available. A case can be made for the establishment of a national database of costing and efficacy information to guide future policy revisions of the South African MDRTB treatment programme, which is resource intensive and of only moderate efficacy. However, due to the widely disparate range of studies on which this evaluation was based, the outcome of the study may not be credible. In this case, the use of a systematic review with subsequent economic modelling could not validly influence policy-makers to change the decision that they made on the basis of drug availability.

Background: Pulmonary Tuberculosis (PTB) is considered a disease of the past but it remains a major cause of mortality among immune compromised patients and continues to be a significant threat to public health globally. Notably, the prevalence of diabetes mellitus (DM) has increased over the years. The biological link of TB and DM has been reported in numerous literature with DM attributed to three folds increase in the risk of TB and linked to Drug Resistant TB, especially amongst aged diabetic patients. The aim of the study was to examine the distribution of DM among TB patients and explore the risk of Drug resistant TB in Diabetics infected with TB Methods: The study employed a retrospective cross-sectional descriptive case based study involving 3638 patients diagnosed with pulmonary TB in the State of Florida, USA, 2009-2014. A comparative analysis of TB cases with DM and cases without DM adjusted for age was conducted. The risk of Drug resistant TB associated with DM was estimated through logistic regression analysis. Odds Ratios of TB/DM comorbidity were calculated and adjusted for Age using 5-year intervals from 40 years to above 70 years. Ninety-five percent (95%) confidence intervals were used and the accepted level of error was 0.05. Results: There were 3836 cases of Pulmonary TB in Florida for the period of 2009-2014. The majority of cases (65%) were males and likely unemployed (59.1%). The prevalence of DM was 12 % but when adjusted for age the prevalence of DM was 3.9% amongst patients aged below 40 years and 16.7 % in patients aged above 40 years. An estimated 469 cases had TB/DM comorbidity (12.2%). The majority of TB/DM cases were above 40 years amongst the patients with DM, 44/469 (9.4%) had drug resistant TB and a majority were resistant to Rifampin. Population density did not influence the distribution of TB in this study. Conclusion: Diabetes Mellitus, Aging, and low immunity are linked with increased rates of progressing from latent TB infection to active disease. To achieve the goal of TB elimination it is important to fully understand and identify known TB comorbidities for proper diagnosis and early initiation to care. There is a positive correlation between high DM burden and increased TB prevalence. Therefore, it is recommended that prevention of DM, hyperglycemia and comprehensive management of DM be intensified to prevent TB, improve TB treatment outcomes and reduce the risk of drug resistant TB in Florida, USA.

Thesis (MScMedSc)--Stellenbosch University, 2014.<br>ENGLISH ABSTRACT: Central dogma suggests that mutations in target genes is the primary cause of resistance to first and second-line anti-TB drugs in Mycobacterium tuberculosis. However, it was previously reported that approximately 5% of Rifampicin mono-resistant clinical M. tuberculosis did not harbor mutations in the rpoB gene. The present study hypothesized that active efflux plays a contributory role in the level of intrinsic resistance to different anti-TB drugs (Isoniazid, Ethionamide, Pyrazinamide, Ethambutol, Ofloxacin, Moxifloxacin, Ciprofloxacin, Streptomycin, Amikacin and Capreomycin in RIF mono-resistant clinical M. tuberculosis isolates with a rpoB531 (Ser-Leu) mutation. This study aimed to define the role of Efflux pump inhibitors (verapamil, carbonylcyanide m-chlorophenylhydrazone and reserpine) in enhancing the susceptibility to different anti-TB drugs in the RIF mono-resistant clinical isolates. The isolates were characterized by determining the level of intrinsic resistance to structurally related/unrelated anti-TB drugs; determining the effect of EPIs on the level of intrinsic resistance in the isolates and comparing the synergistic properties of the combination of EPIs and anti-TB drugs. To achieve this, genetic characterization was done by PCR and DNA sequencing. Phenotyping was done by the MGIT 960 system EpiCenter software to determine the MICs of the different anti-TB drugs and the effect of verapamil and carbonylcyanide m-chlorophenylhydrazone on determined MICs. Due to inability to test reserpine in a MGIT, a different technique (broth microdilution) was used for the reserpine experiment. Additionally; fractional inhibitory concentrations (FIC) indices were calculated for each of these drugs. The FIC assess the anti-TB drugs/inhibitor interactions. STATISTICA Software: version 11 was used for statistical analysis. Results revealed that the RIF mono-resistant isolates were sensitive at the critical concentrations of all 10 drugs tested, with the exception of Pyrazinamide. This could be explained by the technical challenges of phenotypic Pyrazinamide testing. A significant growth inhibitory effect was observed between the combination of EPI and anti-TB drug exposure in vitro. This suggests that verapamil, carbonylcyanide m-chlorophenylhydrazone and reserpine play a significant role in restoring the susceptibility (decrease in intrinsic resistance level) of the RIF mono-resistant isolates to all anti-TB drugs under investigation. Additionally, a synergistic effect was observed by the combination treatment of the anti-TB drugs with the different EPIs. Based on these findings, we proposed a model suggesting that efflux pumps are activated by the presence of anti-TB drugs. The activated pumps extrude multiple or specific anti-TB drugs out of the cell, this in turn decrease the intracellular drug concentration, thereby causing resistance to various anti-TB drugs. In contrast, the addition of EPIs inhibits efflux pump activity, leading to an increase in the intracellular drug concentration and ultimate cell death. This is the first study to investigate the effect of different efflux pumps inhibitors on the level of intrinsic resistance to a broad spectrum of anti-TB drugs in drug resistant M. tuberculosis clinical isolates from different genetic backgrounds. The findings are of clinical significance as the combination of treatment with EPI and anti-TB drugs or use of EPIs as adjunctives could improve MDR-TB therapy outcome.<br>AFRIKAANSE OPSOMMING: Sentrale dogma beweer dat mutasies in teiken gene die primêre oorsaak van die weerstandheid teen anti-TB-middels in Mycobacterium tuberculosis is. Vorige studies het getoon dat ongeveer 5% van Rifampisien enkelweerstandige kliniese M. tuberculosis isolate nie ‘n mutasie in die rpoB geen het nie. Die hipotese van die huidige studie was dat aktiewe pompe 'n bydraende rol speel in die vlak van intrinsieke weerstandheid teen 10 verskillende anti-TB-middels (Isoniasied, Ethionamied, Pyrazinamied, Ethambutol, Ofloxacin, Moxifloxacin, Siprofloksasien, Streptomisien, Amikasien and Capreomycin) in RIF enkelweerstandige kliniese M . tuberculosis isolate met 'n rpoB531 (Ser-Leu) mutasie. Die doel van hierdie studie was om die rol van uitpomp inhibeerders (verapamil, carbonylcyanide m-chlorophenylhydrazone en reserpien) te definieer in die verbetering van die werking vir verskillende anti-TB-middels in die RIF enkelweerstandige kliniese isolate. Die doelstellings van die studie was om die vlak van intrinsieke weerstandigheid teen struktureel verwante/onverwante anti-tuberkulose middels asook die effek van die EPIs op die vlak van intrinsieke weerstand in die isolate is bepaal. Verder is sinergistiese eienskappe van die kombinasie van EPIs en anti-TB-middels ondersoek. Hierdie doelstellings is bereik deur genetiese karakterisering deur PKR en DNS volgorde bepaling. Fenotipering is gedoen deur gebruik te maak van MGIT 960 EpiCenter sagteware om die Minimum Inhibisie Konsentrasie (MIC) van die verskillende anti-TB-middels en die effek van verapamil en carbonylcyanide m-chlorophenylhydrazone op die MIC te bepaal. Reserpien kan nie in die MGIT sisteem getoets word nie, and daarom is 'n ander tegniek (mikro-verdunning) is gebruik om die effek van reserpien te toets. Fraksionele inhiberende konsentrasies (FIC) is bereken vir elk van hierdie middels die anti-TB-middels / inhibeerder interaksies te bepaal. STATISTICA v11 sagteware is gebruik vir alle statistiese analises. Resultate van hierdie studie toon dat die RIF enkelweerstandige isolate sensitief is teen kritieke konsentrasies van al die middels, met die uitsondering van Pyrazinamied. Weerstandigheid van Pyrazinamied kan wees as gevolg van welbekende tegniese probleme met die standaard fenotipiese pyrazinamied toets. ‘n Beduidende groei inhiberende effek is waargeneem tussen die kombinasie van EPI en anti-TB middel blootstelling in vitro. Dit dui daarop dat verapamil, CCCP en reserpine 'n belangrike rol speel in die herstel van die sensitiwiteit (afname in intrinsieke weerstand vlak) van die RIF enkelweerstandige isolate aan alle anti-TB-middels wat ondersoek is. Daarbenewens is 'n sinergistiese effek waargeneem deur die kombinasie van die verskillende anti-TB-middels en die verskillende EPIs. Op grond van hierdie bevindinge het ons ‘n model voorgestel wat toon dat uitvloei pompe geaktiveer word deur die teenwoordigheid van anti-TB-middels en die geaktiveerde pompe dan verskeie of spesifieke anti-TB-middels uit die sel pomp. Dus verminder die intrasellulêre konsentrasie van die middel en veroorsaak daardeur weerstandigheid teen verskeie anti-TB-middels. Die byvoeging van EPIs inhibeer uitvloei pompe se werking en lei tot 'n toename in die intrasellulêre konsentrasie van die middels en uiteindelik die dood van die selle. Hierdie is die eerste studie wat die effek van verskillende uitvloei pompe inhibeerders op die vlak van intrinsieke weerstand teen 'n breë spektrum van anti-TB-middels in die middel-weerstandige kliniese isolate ondersoek. Die bevindinge kan van belangrike kliniese belang wees aangesien die kombinasie van behandeling met EPI en anti-TB-middels die uitkoms MDR-TB terapie kan verbeter.

Peru has the highest burden of multidrug-resistant tuberculosis in the Americas region. Since 1999, the annual number of extensively drug-resistant tuberculosis (XDR-TB) Peruvian cases has been increasing, becoming a public health challenge. The objective of this study was to perform genomic characterization of Mycobacterium tuberculosis strains obtained from Peruvian patients with XDR-TB diagnosed from 2011 to 2015 in Peru. Whole genome sequencing (WGS) was performed on 68 XDR-TB strains from different regions of Peru. 58 (85.3%) strains came from the most populated districts of Lima and Callao. Concerning the lineages, 62 (91.2%) strains belonged to the Euro-American Lineage, while the remaining 6 (8.8%) strains belonged to the East-Asian Lineage. Most strains (90%) had high-confidence resistance mutations according to pre-established WHO-confident grading system. Discordant results between microbiological and molecular methodologies were caused by mutations outside the hotspot regions analysed by commercial molecular assays (rpoB I491F and inhA S94A). Cluster analysis using a cut-off ≤ 10 SNPs revealed that only 23 (34%) strains evidenced recent transmission links. This study highlights the relevance and utility of WGS as a high-resolution approach to predict drug resistance, analyse transmission of strains between groups, and determine evolutionary patterns of circulating XDR-TB strains in the country.<br>Revisión por pares

Tuberculosis (TB) is the ninth leading cause of death worldwide, with an estimated 1.7 billion people currently affected by the disease. Multidrug resistant tuberculosis (MDR-TB) is not responsive to the most effective first-line drug treatments, and is a significant public health issue facing many nations including Vietnam. New drug regimens that improve treatment outcomes and reduce toxicity are urgently needed. However, the specific factors associated with poor treatment outcomes in Vietnam have not been well characterised. This thesis explores major obstacles to successful outcomes for patients with drug-resistant TB in Vietnam. Firstly, patient-related factors associated with poor outcomes were explored in a retrospective cohort study among patients treated for MDR-TB in two provinces. Second, treatment-related factors were evaluated through a systematic review and meta-analysis. This explored the incidence of ototoxicity due to injectable antibiotics, which can contribute to long-term morbidity even after treatment has been ‘successful’. Together, these studies highlight major challenges in the programmatic management of MDR-TB and highlight the urgent need for new approaches to control drug-resistant TB in resource-limited settings.

Multidrug-resistant Mycobacterium tuberculosis (MDR-TB) is a leading cause of morbidity and mortality in the Philippines. The purpose of this study was to gain knowledge about the relationship between potential risk factors and MDR-TB. Risk factors (the independent variables) for MDR-TB (the dependent variable) include previous TB treatment, infection with HIV, exposure to patients with drug-susceptible TB/MDR-TB, delays in diagnosis and treatment, employment status, smoking, imprisonment, alcohol abuse, and poor compliance with TB treatment regimens. The study was based on the epidemiological approach to causal inference work. A case-control study design was used wherein a quantitative method was applied in data analysis to assess the strength of the pre-identified possible risk factor(s) association to MDR-TB infection. Data were collected using survey questionnaires that were administered to patients (N = 172) from health centers in Leyte, San Mateo Rizal, and San Lazaro. Hypotheses were tested using chi-square analysis, Fisher's exact test, and an odd ratio. Drug-susceptible TB respondents who smoked on a daily basis were three times more likely (95% CI 1.021-13.341, OR 3.69) to develop an MDR-TB infection than were other respondents. Respondents who did not comply with the anti-TB treatment regimen were nine times more likely (95% CI 2.104-43.059, OR 9.519) to develop an MDR-TB infection than other respondents. Health care providers may be able to use study findings to develop programs to help drug-susceptible TB patients stop smoking and better comply with treatment regimens designed to prevent MDR-TB infection, resulting, potentially, in improved public health outcomes for patients.

Chez les patients traités par un régime posologique, La concentration sérique moyenne et l'écart type de la concentration SMX était 161,01 ± 69,154 mg/L et de 5,788 ± 2,74 mg/L pour le TMP. La concentration minimale inhibitrice 90% (CMI 90) était de 10 mg/L pour le cotrimoxazole et la sulfadiazine contre Mycobacterium tuberculosis. Toutes les mycobactéries étaient inhibées par 20 mg/L de cotrimoxazole et de sulfadiazine. Les CMI de l'ivermectine contre 13 souches complexe M. tuberculosis ont varié entre 10 et 40 mg/L. En outre, tous isoler M. tuberculosis étaient résistants à la squalamine avec CMI &gt; 100 mg/L. Dans une autre partie nous avons montré que tous les isolats du complexe Mycobacterium avium étaient résistants au triméthoprime avec une CMI &gt; 200 mg/mL. Le cotrimoxazole, le sulfaméthoxazole et la sulfadiazine ont montré une CMI respectivement de 10 mg/L, 25 mg/L et 20 mg/L, à l'exception de Mycobacterium chimaera qui présentait une CMI de 10 mg/L pour ces molécules. La comparaison de la séquence du gène de la dihydroptéroate synthase de M. intracellulare et M. chimaera a montré seulement quatre changements d'acides aminés<br>Firstly, we measured the serum concentration of Sulfamethoxazole (SMX)-Trimethoprim (TMP) in patients treated with high dosage regimen. The mean values and standard deviation for SMX concentration was 161.01± 69.154 mg/L and of 5.788 ± 2.74 mg/L for TMP. Susceptibility testing yielded a minimum inhibitory concentration 90% (MIC90) of 10 mg/L for cotrimoxazole and sulfadiazine. All M. tuberculosis complex mycobacteria (MTC) were inhibited by 20 mg/L cotrimoxazole and sulfadiazine. Also, the MICs of ivermectin varied between 10 and 40 mg/L, against 13 MTC mycobacteria. Moreover, all M. tuberculosis isolate were resistant to squalamine with MIC &gt; 100 mg/L. Also, all Mycobacterium avium complex (MAC) isolates were resistant to trimethoprim with MIC &gt; 200 mg/L. Cotrimoxazole, sulfamethoxazole and sulfadiazine exhibited MIC of 10 mg/L, 25 mg/L and 20 mg/L, respectively against all tested MAC isolates except for Mycobacterium chimaera which exhibited MICs of 10 mg/L for these molecules. Comparing the DHPS gene sequence in M. intracellulare and M. chimaera type strains and clinical isolates yielded only four amino acid changes

Thesis (MScMedSc)--Stellenbosch University, 2015.<br>ENGLISH ABSTRACT: Drug resistance in Mycobacterium tuberculosis is an increasing global problem. Drug resistance is mostly caused by single nucleotide polymorphisms (SNPs) within the bacterial genome. This observed increase in global incidence of drug resistant tuberculosis (TB) has sparked the search for new anti-TB drugs and the repurposing of drugs that are currently used against other organisms or species of mycobacteria. One such repurposed drug, clofazimine (CFZ), is currently used for the treatment of leprosy, caused by Mycobacterium leprae. The mechanism of action of CFZ is not clear, but it is hypothesized that CFZ is reduced by a mycobacterial type II NADH oxidoreductase (NDH-2). The reduction of CFZ drives the production of reactive oxygen species (ROS) which is toxic to the pathogen. The aim of this study was to elucidate the mechanism of CFZ resistance. Towards this aim, spontaneous in vitro CFZ resistant mutants were selected, characterized and whole genome was used identify SNPs which may cause CFZ resistance. Mutations were identified in a transcriptional regulator encoded by Rv0678, fatty-acid-AMP ligase, or FadD28 (Rv2941) and glycerol kinase or GlpK (Rv3696c). Mutations in Rv0678 have previously been shown to play a role in both CFZ resistance and bedaquiline (BDQ) cross-resistance, while no link has been found between CFZ resistance and mutations in fadD28 and glpK. The novel, non-synonymous SNP identified in Rv0678 resulted in the replacement of an alanine residue with threonine at codon 84, which is located in the DNA binding domain. Virtual modelling of the mutated Rv0678 protein showed that the A84T mutation may influence DNA binding, possibly due to its proximity to the DNA binding domain. This mutation caused a change in hydrophobicity, which may influence binding to DNA. Previous studies showed that mutations in Rv0678 resulted in the upregulation of mmpL5, a putative efflux pump. However, the mechanism whereby CFZ resistance occurs via increased abundance of this efflux pump in the cell wall is not clear and needs further investigation. The cross-resistance between CFZ and BDQ, caused by mutations in Rv0678, is of concern and may influence the planning of anti-TB drug regimens for the future. The roles of the other two mutations identified in this study in CFZ resistance is also not clear and requires further investigation. Finally, the findings of this study support the role of Rv0678 in CFZ resistance thereby suggesting that this gene could be useful as a diagnostic marker to test for CFZ resistance in clinical isolates.<br>AFRIKAANSE OPSOMMING: Middelweerstandigheid in Mycobacterium tuberculosis is 'n wêreldwye toenemende probleem. Middelweerstandigheid word meestal veroorsaak deur enkel nukleotied polimorfismes (SNPs) in die bakteriële genoom. Hierdie toename in middelweerstandige tuberkulose (TB) het gelei tot die soektog na nuwe anti-TB-middels en die alternatiewe aanwending van middels wat tans teen ander organismes of spesies van mikobakterieë gebruik word. Een so 'n alternatiewe middel, clofazimine (CFZ), word tans gebruik vir die behandeling van melaatsheid wat veroorsaak word deur Mycobacterium leprae. CFZ se meganisme van werking is nie duidelik nie, maar dit word vermoed dat CFZ gereduseer word deur 'n mikobakteriële tipe II NADH oksidoreduktase (NDH-2). Die reduksie van CFZ dryf die produksie van reaktiewe suurstof spesies wat giftig is vir die patogeen. Die doel van hierdie studie was om die meganisme van CFZ weerstandigheid te ondersoek. Om hierdie doel te bereik was spontane in vitro CFZ weerstandige mutante gekies, gekarakteriseer en heel genoom volgorde bepaling is gebruik om SNPs te identifiseer wat CFZ weerstandigheid veroorsaak. Mutasies in Rv0678, 'n transkripsie reguleerder, vetsuur-AMP ligase, of FadD28 (Rv2941) en gliserol kinase of GlpK (Rv3696c) geïdentifiseer. Dit is al voorheen gevind dat mutasies in Rv0678 ‘n rol speel in beide CFZ weerstandigheid en bedaquiline (BDQ) kruis-weerstandigheid, terwyl geen verband gevind is tussen CFZ weerstandigheid en mutasies in fadD28 en glpK nie. Die nuwe, nie-sinonieme SNP, geïdentifiseer in Rv0678 het gelei to die vervanging van 'n alanien aminosuur met treonien by kodon 84, wat geleë is in die DNS bindings domein. Virtuele modellering van die gemuteerde Rv0678 proteïen het getoon dat die A84T mutasie DNS binding moontlik kan beïnvloed, as gevolg van sy nabyheid aan die DNS bindings domein. Hierdie mutasie veroorsaak 'n verandering in die hidrofobiese natuur, wat DNS binding kan beïnvloed. Vorige studies het getoon dat mutasies in Rv0678 lei tot die opregulering van mmpL5, 'n waarskynlike uitvloei pomp. Die meganisme waardeur CFZ weerstandigheid veroorsaak, deur ‘n groot aantal van hierdie uitvloei pompe in die selwand, is nie duidelik nie en moet verder ondersoek word. Die kruis-weerstandigheid tussen CFZ en BDQ, wat veroorsaak word deur mutasies in Rv0678, is van belang en kan die beplanning van anti-TB middel behandeling vir die toekoms beïnvloed. Die rolle van die ander twee mutasies, wat in hierdie studie geïdentifiseer is, in CFZ weerstandigheid is ook nie duidelik nie en vereis verdere ondersoek. Ten slotte, die bevindinge van hierdie studie steun die rol van Rv0678 in CFZ weerstandigheid en dit dui daarop dat hierdie geen gebruik kan word as 'n diagnostiese merker om vir CFZ weerstandigheid te toets in kliniese isolate.

Objective The consistent emerging of multidrug-resistant tuberculosis (MDR-TB) cases are increasingly becoming a major threat and challenge in global TB control, especially in some resource-limited settings like India, China, South Africa. Currently there is no widely acknowledged treatment strategy for MDR-TB. Effectiveness and of current DOTS-Plus strategy is remaining controversial. This systematic review aims to investigate treatment outcomes for MDR-TB under DOTS-Plus and potential factors associated with poor outcome (death, default and failure). Methodology The literatures were searched in Pubmed, Medline, the Cochrane library, Essential Evidence Plus, EMBASE and CNKI. Some manual search articles were also added and 164 literatures in total were founded related to treatment outcomes for multidrug resistant patients under DOTS-Plus. After basically screening and carefully full-text reading, nine studies meeting the inclusion criteria were included. A total of 3358 participants from 8 high MDR-TB countries were investigated. Result Baseline characters were varied across these nine studies, including HIV prevalence (0-1.6%), MDR-TB prevalence (0-4.7%), previous treatment history (without TB treatment, with TB treatment but not under directly observed therapy, short courses (DOTS) and with TB treatment under DOTS), and male/female ratio (54%-86.5%). All studies reported a successful outcome rate (cure and complete) higher than 60 percent, and three of the studies reported higher than 70 percent, which are comparatively high in MDR-TB treatment. Factors associated with poor outcomes that reported by these studies were including alcohol use/ abuse, homelessness, unemployment, imprisonment, BMI, cavitary and bilateral disease, missing doses, and resistant to some second-line drugs. Conclusion In sum, the overall treatment outcomes from these nine studies under DOTS-Plus were acceptable, and most of them were satisfactory. Nevertheless, in consideration of potential bias arising from these cohort analyses, conclusions should be drawn carefully. Several major challenges restrict low- and middle- income countries from implementing DOTS-Plus, which put high command on TB infrastructure, policy commitment, human resources and financial support. Further effort could be put on systematical review and meta-analysis on cost-effectiveness of DOTS-Plus programs. In China, policy makers should pay attention to arrive at national and provincial guidelines of MDR-TB treatment under DOTS-Plus.<br>published_or_final_version<br>Public Health<br>Master<br>Master of Public Health

Background: There is widespread concern about the rise of drug-resistant TB because treatment outcomes of affected patients remain poor and treatment options are limited. After more than a forty-year gap without any breakthrough discovery, several new (bedaquiline and delamanid) and repurposed drugs (linezolid) are increasingly becoming available for use. However, data regarding the efficacy and safety of these drugs in drug-resistant TB patients, with or without HIV infection, from a real-life programmatic setting are lacking. This thesis aims to address that knowledge gap and provide information for management of drug-resistant TB in countries with high disease burden. Methods: A total of 326 drug resistant TB patients were prospectively followed up between January 2008 and April 2018. The efficacy and safety of two new drugs (bedaquiline and delamanid) and one repurposed drug (linezolid) was determined in these patients in three studies. In the first study, 24 months treatment outcomes and adverse event profiles were compared between extensively drug resistant (XDR) TB patients who received programmatic treatment regimens with the backbone of second line injectables and fluoroquinolones (nonbedaquiline-based) and those who received a bedaquiline- and/ or linezolid-based treatment regimen. The second study determined the frequency of system-specific adverse events associated with linezolid. The third study interrogated the safety and effectiveness of a strengthened treatment regimen containing a combination of delamanid and bedaquiline in patients with poor prognostic features compared to bedaquiline-based regimen. Results: In the first study, patients who received a bedaquiline-based treatment regimen had a significantly greater favourable outcome rate (66.2% vs 13.2%; p<0.001) ), more than a fourfold reduction in treatment failure rate (5.9% vs 26%; p<0.001 ) and less than a half of mortality rate compared to patients who received a non-bedaquiline-based regimen. The bedaquiline survival and favourable outcome effect remained significant in HIV-infected patients (p<0.001). The second study showed that linezolid interruption was common in patients receiving a bedaquiline-based treatment regimen, and that system-specific toxicity occurred within predictable time frames. It also showed that anaemia (77.3% versus 7.3%; p<0.001), peripheral neuropathy (63.6% versus 14.6%; p=0.003), and optic neuritis (18.2% versus 9.8%; p=0.34) occurred more frequently in linezolid interrupters than in non-interrupters. The third study showed that the use of delamanid-bedaquiline combination regimen was safe and efficacious in drug resistant TB patients with poor prognosis when compared with outcomes in the less sick patients who received a bedaquiline-based regimen. It also showed no significant difference in culture conversion rate at 6 months (92.5% versus 81.8%; p=0.26) or favourable treatment outcome rate (63.4% versus 67.5%; p=0.66) between the two groups. Although patients who received the combination regimen had more frequent occurrence of QTcF prolongation greater than 60 ms from baseline (p=0.001) and more episodes of QTcF greater than 450 ms during treatment (p=0.001), none of them were symptomatic or had delamanid or bedaquiline withdrawn from their regimen. Conclusion: These data demonstrated that new and repurposed drugs remarkably improved treatment outcomes in patients with drug-resistant TB. Although linezolid, which is an important component of the bedaquiline-based treatment regimen, is often associated with system-specific adverse events, these occurred at predictable time frames thereby guiding physicians to make informed management decisions. Lastly, drug resistant TB patients with poor prognosis may benefit from a regimen containing delamanid and bedaquiline which seems relatively safe from an adverse event perspective. These data, despite some limitations, make a case for a widespread and accelerated roll-out of new and repurposed drugs for the treatment of drug resistant TB.

Mycobacterium tuberculosis (MTB) is a major infective agent causing human tuberculosis (TB) in the worldwide. Although tuberculosis can be treated by a six-month course of antibiotics, the prevalence of extensively drug-resistance TB (XDR-TB) made the disease becomes a global health problem. In addition to the conventional MTB detection methods, molecular methods become significant in drug resistant MTB detection which can enhance effective drug treatment. In this study, 200 MTB respiratory specimens were collected from patients with suspected tuberculosis in Tuen Mun Hospital in Hong Kong. Based on the culture method as a gold standard for MTB detection, the presence of MTB in clinical samples was determined by IS6110single tube nested real-time PCR. In addition, by using High Resolution Melting (HRM) analysis, the presence of mutant type KatG315 gene for detecting isoniazid resistant MTB was determined. Among 66 MTB culture positive samples, 10 samples had positive acid fast bacilli (AFB) smears giving the diagnostic sensitivity 15.1%. IS6110 single tube nested PCR was amplified in 51 specimens giving 77.2% MTB detection sensitivity and 97.8% specificity. Among 51 samples positive for IS6110 PCR, 66.7% showed successful amplification in subsequent KatG-HRM assay. Two samples were confirmed to be isoniazid (INH) resistance in Public Health Laboratory Centre (PHLC). However, there was only one sample showing detectable KatG315 mutation in clinical specimen by using HRM while the other was only detected in the corresponding culture isolate. From the result of this study, single tube nested real-time PCR demonstrated MTB detection in clinical samples and INH resistant strain with KatG315mutationcan be detected by HRM analysis. Early detection of mycobacteria allow earlier treatment of the patient, thus transmission of the disease can be controlled.<br>published_or_final_version<br>Microbiology<br>Master<br>Master of Medical Sciences