Dissertations / Theses on the topic 'Invasive fungal infection'

Les infections fongiques invasives, sont des infections sévères grevées d’une lourde mortalité. Elles sont actuellement un problème majeur de santé publique et leur incidence augmente. Les candidémies représentent la quatrième cause d’infection hématogène nosocomiale aux Etats-Unis, les cryptococcoses sont responsables de 600 000 décès chaque année en Afrique et l’aspergillose invasive infecte 10% des patients transplantés de cellules souches. La mortalité de ces infections reste élevée avec des taux de mortalité de 50, 15 et 40% respectivement. L’augmentation de leur incidence est due à l’accroissement des populations immunodéprimées à risque de développer des infections fongiques en raison de l’augmentation des thérapeutiques immunosuppressives et de l’allongement de la durée de vie des patients immunodéprimés. Les infections fongiques invasives surviennent chez des patients immunodéprimés, majoritairement dans un contexte d’immunodépression acquise (neutropénie, chimiothérapie, greffe de cellules souches périphériques ou transplantation d’organe solide, diabète, infection par le virus de l’immunodéficience humaine), mais également secondairement à un déficit immunitaire héréditaire (granulomatose septique chronique, déficit immunitaire combiné, neutropénie congénitale, défaut de l’axe IFNγ-IL12). Cependant certains patients développent des infections fongiques invasives sans immunodépression ou facteurs de risques identifiés. Nous avons donc émis l’hypothèse que ces infections avaient possiblement une origine génétique non identifiée. Au cours de ma thèse, j’ai étudié une cohorte de patients présentant des infections fongiques invasives sans facteur favorisant identifié afin de rechercher une étiologie génétique à ces infections. Le premier groupe de patients que j’ai étudié présentait une dermatophytose invasive ou dermatophytose profonde sans immunodépression. Contrairement à la dermatophytose superficielle, en général bénigne et fréquente dans la population générale; la dermatophytose profonde est une infection rare, invasive et sévère, dans laquelle les dermatophytes (qui sont des champignons filamenteux) envahissent les tissus dermiques et hypodermiques, les ganglions et parfois les organes profonds. Les patients que j’ai étudié étaient tous originaires d’Afrique du Nord, pour la plupart issus de familles consanguines, dont certains avec des cas multiples. Ces observations suggéraient une origine génétique de la dermatophytose profonde avec une hérédité probablement récessive. Au cours de ma thèse, j’ai étudié les caractéristiques cliniques, immunologiques et génétiques de 18 patients atteints d’une dermatophytose profonde, issus de neuf familles Marocaines, Algériennes, Tunisiennes ou Egyptiennes. En parallèle, j’ai étudié des patients ayant présenté des infections fongiques avec localisations cérébrales. L’une de ces patients a présenté des abcès cérébraux suite à une infection disséminée à Exophiala dermatitidis et trois patients ont développé des infections du système nerveux central à Candida spp.. Les infections invasives à Exophiala dermatitidis sont des infections rares, avec de fréquentes atteintes du système nerveux central, survenant majoritairement chez des patients sans déficit immunitaire identifié suggérant l’existence d’une origine génétique probable méconnue chez ces patients. Les candidoses invasives surviennent habituellement chez des patients neutropéniques, ayant récemment subi une intervention chirurgicale ou étant porteurs d’un cathéter intraveineux. Parmi les candidoses invasives, les localisations au système nerveux central sont rares, et classiquement rapportées chez des nouveau-nés prématurés ou suite à une intervention neurochirurgicale. J’ai par ailleurs étudié une patiente ayant développé des infections invasives des tissus sous-cutanés et des adénopathies dues à un champignon filamenteux. (...)
Invasive fungal diseases are a major health problem as they are severe infections complicated with high mortality rates and with rising incidence. Invasive fungal diseases occur mainly in patients with acquired immunodeficiencies, but also with primary immunodeficiencies (chronic granulomatous disease, defect in IFN-ϒ/IL-12 axis, congenital neutropenia). However, few patients develop invasive fungal disease without known risk factor. We therefore hypothesized that these infections probably have an unidentified genetic etiology. I studied a cohort of patients who developed invasive fungal diseases without risk factors and searched for a genetic etiology to their infections. The first group of patients presented with deep dermatophytosis without known immunodeficiency. Deep dermatophytosis is a rare, invasive and severe infection where dermatophytes invade dermis, hypodermis, lymph nodes and sometimes deep organs. I could study clinical, immunological and genetic characteristics of 18 patients from nine families who presented deep dermatophytosis. I also studied patients who developed central nervous system (CNS) fungal infections; one patient with CNS Exophiala dermatitidis infection and three patients with CNS Candida spp. infection. Invasive E. dermatitidis infections are rare, with frequent CNS location, mainly reported in patients without known immunodeficiencies, suggesting a potential unknown genetic etiology in these patients. CNS candidiasis are also rare infections usually occuring in preterm neonates or following neurosurgery. Based on literature data previously reporting a large consanguineous Iranian family with CARD9 deficiency that developed chronic mucocutaneous and central nervous system candidiasis; according to candidate gene approach, I sequenced CARD9 in all patients. CARD9 is an adaptor protein expressed by myeloid cells that signals downstream Dectin-1 and Dectin2 that are the main Pattern Recognotion Receptor implicated in antifungal immunity. I identified in all studied patients homozygous CARD9 mutations. Among 18 patients with deep dermatophytosis, 16 had homozygous nonsense Q289X and two homozygous missense R101C mutation in CARD9. I identified R18W, R35Q and R70W homozygous missense mutations in the patients who developed E. dermatitidis and two patients who developed CNS candidiasis, respectively. Transmission was autosomal recessive for all patients, except for the one with E. dermatitidis infection who had an uniparental disomy. In contrast with controls, CARD9 expression is abolished in Q289X, reduced in R70W and normal in R18W patients’ myeloid cells. CARD9 deficient patients whole blood and dendritic cells display a selective response defect to Candida albicans and Saccharomyces cerevisiae ; with IL-6 and TNF-α production impairment after Candida albicans and Saccharomyces cerevisiae stimulation. This defect can explain elective fungal susceptibility of CARD9 deficient patients to invasive fungal infections. This work evidenced that CARD9 deficiency was the main genetic etiology of deep dermatophytosis. It also could evidence that CARD9 deficiency is associated with Exophiala dermatitidis and Candida spp. CNS infections. This susceptibility is associated with proinflammatory cytokines defect by dendritic cells and whole blood to fungal agents. Various fungal clinical phenotypes in CARD9 deficient patients assess CARD9 central role in skin and central nervous system antifungal immunity

Objective: To review the place in therapy of isavuconazole, the active metabolite of isavuconazonium sulfate, via a review of the available literature on drug chemistry, spectrum of activity, pharmacokinetic/pharmacodynamic profile and trials assessing clinical efficacy and safety. Methods: Relevant data, original research articles and reviews, were gathered primarily through the use of a PubMed database search. The search was conducted without date restrictions in order to collect both historical and recent data regarding isavuconazole. Key findings: Isavuconazole is a triazole currently approved not only for use in invasive aspergillosis and mucormycosis but also has demonstrable activity against Candida species and other common fungal pathogens. This drug has features which make it more clinically appealing compared to other azoles with similar indications. In specific, isavuconazole does not require a cyclodextrin vehicle due to its water solubility, and at present, does not require therapeutic drug monitoring. Moreover, isavuconazole has displayed improved safety and tolerability compared to voriconazole. Available data from Phase III clinical trials shows isavuconazole to be a possible therapeutic option to currently available therapies for which it is approved; however, clinical conclusions should be reserved until results have been published and more data from clinical use is reported. Conclusions: Isavuconazole is a new triazole with broad‐spectrum antifungal activity including invasive aspergillosis and mucormycosis.

Understanding the biotic factors influencing invasive plant performance is essential for managing invaded land and preventing further exotic establishment and spread. I studied how competition between both conspecifics and native co-habitants and arbuscular mycorrhizal fungal (AMF) impacted the success of the invasive bunchgrass Brachypodium sylvaticumin early growth stages. I examined whether invasive plants performed and competed differently when grown in soil containing AMF from adjacent invaded and noninvaded ranges in order to determine the contribution of AMF to both monoculture stability and spread of the invasive to noninvaded territory. I also directly manipulated common mycelial network (CMN) formation by AMF to determine hyphal network contribution to competitive interactions. I found that invasive plants performed most poorly (as indicated by decreased chlorophyll content, size and shoot dry mass) in invaded range soil against conspecifics. This could be two-pronged evidence for existing biotic pressure on the invasives to expand into adjacent noninvaded ranges. I also found a negative effect of AMF colonization and invasive plant performance, potentially indicating deleterious plant-soil feedbacks which could help maintain plant biodiversity at a community level. CMN effects were found to be interactive with root competition and directly affected the performance and nutrient status of B. sylvaticum. Although no direct correlations between AMF colonization levels and competition were found, CMN presence contributed significantly to plant growth and nutrient status. Therefore AMF, through infection and CMN formation, may be able to influence invasive plant growth and spread in the field.

La mucormycose pulmonaire est une infection fongique invasive grave affectant les patients immunodéprimés. Le traitement de référence fait appel à l’amphotéricine B (AmB) liposomale mais reste peu efficace avec environ 50% de mortalité malgré celui-ci. Le but de cette thèse était d’optimiser le traitement préventif et curatif de la mucormycose pulmonaire. Pour cela, cette thèse a été structurée en 2 axes, un axe préventif puis un axe curatif, eux-mêmes divisés en deux sous-parties.La première partie de l’axe « préventif » s’intéressait au phénomène de réactivation des infections fongiques invasives. Ce concept a été décrit dans un premier article. Son postulat est le suivant : suite à une primo-infection asymptomatique, une seconde infection peut se produire à distance à la faveur d’une immunodépression. Un modèle murin a été développé pour reproduire ce concept et évaluer l’intérêt de l’AmB en décolonisation pour prévenir ce phénomène de réactivation. L’AmB en décolonisation s’est révélé efficace pour prévenir la survenue de la maladie.La seconde partie de cet axe avait pour but d’étudier le rôle des corticoïdes dans la physiopathologie de l’infection. Pour ce faire, un modèle ex vivo qui consiste à administrer des corticoïdes à des souris, puis à récupérer les cellules pulmonaires par lavage broncho-alvéolaire a été mis au point. Les perturbations induites par les corticoïdes sur les cellules immunitaires ont ensuite été étudiées in vitro. Les corticoïdes ont diminué la capacité globale des macrophages alvéolaires à inhiber la filamentation du champignon, diminué la capacité de phagocytose des macrophages alvéolaires et leur capacité de « killing » oxydatif.La première partie de l’axe « curatif » a consisté à développer un modèle murin de mucormycose pulmonaire aigüe afin d’étudier la physiopathologie de cette infection. Ce modèle a été caractérisé sur les plans histologiques et immunitaires et permettra d’explorer la relation champignon-hôte-antifongique. La seconde partie de cet axe a permis d’évaluer in vitro des associations entre AmB et diverses molécules afin d’améliorer l’efficacité de l’AmB. Ces combinaisons ont été testées par technique de chequerboard sur différentes souches de Mucorales. Après avoir passé au crible 20 candidats (antibiotiques, antifongiques, alcools terpéniques, tensioactifs), un a été identifié, le PEG15HS, qui permet de diminuer les concentrations minimales inhibitrices d’AmB
Pulmonary mucormycosis are life-threatening invasive fungal infections affecting immunocompromised patients. First-line treatment is based on liposomal amphotericin B (AmB). Despite treatment, mortality remains high. The aim of this thesis was to optimize preventive and curative treatments of pulmonary mucormycosis. This thesis was divided in 2 axes, curative and preventive, themselves divided in two parts.The first aim of preventive axis was to study reactivation of mucormycosis. This concept was described in a first publication. Fungi can remain latent after an asymptomatic primary infection. After a latency period, they may be reactivated in the event of major immune deficiency leading to symptomatic infection. A mouse model was developed to reproduce this concept and assess AmB as decolonizing treatment. Decolonization using AmB was effective to prevent the disease.In the second part of this axis, the role of corticosteroids in infection pathophysiology was studied. An ex vivo model was developed to expose mouse alveolar macrophages to an infection-triggering dose of corticosteroids. In this model, corticosteroids were administered to naive mice, and then alveolar macrophages were collected by bronchoalveolar lavage. Alterations induced by corticosteroids on alveolar macrophages co-incubated with fungal spores were then studied in vitro. Corticosteroids decreased alveolar macrophage capacity to control fungal growth through phagocytosis and oxidative burst alterations.In the first part of curative axis, an acute pulmonary mucormycosis model was developed to study physiopathology of this infection. This model will be used to explore fungal-host-antifungal relationship.In the second part of this axis, in vitro combinations using AmB and several compounds were evaluated in order to improve AmB efficacy. These combinations were tested by checkerboard assays on several strains of Mucorales. After screening of 20 compounds (antibiotics, antifungal agents, terpene alcohols, surfactants), a candidate was identified, PEG15HS, which decreased AmB minimum inhibitory concentrations

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Infecções fúngicas invasivas têm se tornado cada vez mais freqüentes em neonatos, principalmente devido ao aumento da sobrevivência de prematuros e a deficiência do sistema imune. Dessa forma, torna-se relevante o conhecimento dos fatores epidemiológicos e susceptibilidade aos antifúngicos, uma vez que permitem o melhor conhecimento dos fatores associados à doença e a resistência dos agentes etiológicos, além da concentração ideal do medicamento a ser administrado para inibir e /ou matar o agente causal da infecção. Nesse contexto, os objetivos deste estudo foram diagnosticar candidemia em neonatos, associando os fatores epidemiológicos predisponentes e o perfil de susceptibilidade às drogas antifúngicas dos agentes etiológicos. No período de março de 2010 a julho de 2011, foram feitas coletas das amostras clínicas em neonatos de Unidades de Terapia Intensiva Neonatal do Hospital Agamenon Magalhães e do Instituto de Medicina Integral Professor Fernando Figueira. O diagnóstico micológico foi realizado através do exame direto, cultura e identificação dos agentes etiológicos. Foram coletadas amostras de sangue de 301 pacientes e isoladas 30 culturas, sendo identificadas Candida albicans (11), C. parapsilosis (11), C. pelliculosa (5), C. glabrata (1), C. guilliermondii (1) e C. tropicalis (1). Dos 30 pacientes com hemoculturas positivas para fungos, 90% eram pré-termos, 60% do sexo masculino, 93,4% possuíam peso ao nascer inferior a 2,5kg e as condições clínicas mais associadas foram icterícia e síndrome do desconforto respiratório. A grande maioria dos pacientes fazia uso de dispositivo terapêutico invasivo, destacando-se nutrição parenteral (96,7%) e cateterismo umbilical (73,3%). Quanto à susceptibilidade antifúngica todos os isolados de levedura foram sensíveis a anfotericina B, porém foi observada resistência ao fluconazol e voriconazol, principalmente por C. albicans, e 7 dos 11 isolados de C. parapsilosis foram resistentes a anidulafungina. As infecções fúngicas invasivas são frequentes em neonatos, permanecendo as espécies de Candida como as mais isoladas. Pacientes prematuros de baixo peso e que fazem uso de dispositivos invasivos são os mais acometidos, o conhecimento destes dados aliados aos resultados de susceptibilidade antifúngica in vitro possibilitam a prevenção e o tratamento mais adequado destas infecções.
Invasive fungal infections have become increasingly frequent in neonates, due to the increased survival of premature and disability of the immune system. The knowledge of epidemiological factors of these infections, as well as testing susceptibility to antifungal agents is relevant in this group of patients, because they allow a better understanding of the factors associated with the disease, the evaluation of the occurrence of fungal resistance, and the optimal concentration of the drug to be administered to inhibit and / or kill the agent of infection. In this context, the objectives of our study were to detect candidemia in neonates, the epidemiological factors associated with these infections and determine the antifungal susceptibility profile of the isolates. The samples were collected in the Neonatal Intensive Care Units from Agamenon Magalhães Hospital and Institute of Integrative Medicine Fernando Figueira, according to the medical request, from March 2010 to July 2011. The samples were manipulated to perform the direct examination and culture and then purified and identified. Samples were collected from 301 patients and we had isolated yeasts in 30 samples of blood , they were identified as Candida albicans (11), C. parapsilosis (11), C. pelliculosa (5), C. glabrata (1), C. guilliermondii (1), C. tropicalis (1). Of the 30 patients with positive blood cultures for fungi, 90% were preterm, 60% male, 93.4% had birth weight below 2.5 kg and the more usual conditions associated were clinical jaundice and respiratory distress syndrome. The vast majority of patients used invasive therapeutic device, especially parenteral nutrition (96.7%) and umbilical catheterization (73.3%). The antifungal susceptibility showed that all isolates were sensible to amphotericin B but some were resistente to fluconazole and voriconazole, mainly species of C. albicans, and 7 of 11 isolates of C. parapsilosis were resistant to anidulafungin. Invasive fungal infections are common in neonates, remaining Candida species as the most isolated. Preterm infants with low birth weight and use of invasive devices are the most affected and this knowledge combined with the in vitro antifungal susceptibility results enables a better prevention and treatment of these infections.

Fungal infections are ignored by social and political communities. However, they are estimated to affect more than a billion people, resulting in approximately 11.5 million life-threatening infections in the 'at risk' population and more than 1.5 million deaths annually. Though there have been huge advances in diagnostics and antifungal drug development over the past two decades, however, resource limited settings have not benefited from these advances. The aim of this research was to determine the burden of serious fungal infections in Nigerians with the appropriate underlying diseases. This epidemiological research was conducted across four study populations. Study 1; HIV-infected patients with CD4+ counts < 250 cells/mm³, irrespective of their ART status, a CrAg lateral flow assay was used for detecting cryptococcal antigenaemia (n=214). Study 2; a cross-sectional multicentre survey of TB patients being managed for smear negative or treatment failure TB irrespective of their HIV status (n=208). Study 3; a multicentre histoplasmin skin sensitivity survey amongst healthy HIV-infected and non-HIV infected participants; intradermally; induration ≥ 5 mm was considered to be histoplasmin positive (n=750). Study 4; a prospective cohort study of critically ill patients in a Nigerian ICU (n=71). Two retrospective studies to analyse the clinical picture of serious fungal infections in two at risk populations (HIV/AIDS and neonatal intensive care babies) in Nigerians was also conducted (n=7034; n=2712 respectively). Results revealed an overall seroprevalence of cryptococcal antigenemia of 8.9% with 6 (9.8%) in those with CD4+ cell counts < 100cells/mm³, 4 (5.0%) in the 100-200 group and 9 (12.3%) in 200-250 cells/mm³ group; a CPA prevalence of 8.7% (6.5% had HIV infection and 14.5% were HIV-negative) and a prior subclinical histoplasmosis of 4.4%. The ICU study revealed a 45% healthcare associated infection rate representing an incidence rate of 79/1000 patient-days in the ICU. The retrospective studies revealed a 2.3% rate of neonatal ICI with a case fatality rate of 18.5%. In the 12 years retrospective study 18% had a fungal OI with 88% of patients having initiated ART. In conclusion, serious fungal infections do occur in the at risk population in Nigeria and they constitute a significant public health challenge. Our findings demonstrate that there has been an underestimation of the burden of the problem in Nigerians. There is a dire need to design guidelines for the management of fungal infections in at risk population.

Depuis la disponibilité des combinaisons antirétrovirales (cART) en 1996, l’incidence des infections opportunistes classantes SIDA (IO), dont la pneumocystose (PCP) a très fortement diminué. Malgré tout, chez les patients infectés par le VIH, la PCP était la 2ème IO la + fréquente en France en 2001-2003 et les infections fongiques, avec 1 million de nouveaux cas/an de cryptococcose, restent un problème de santé publique majeur au niveau mondial. Cependant, depuis l’ère des cART, très peu de recherches épidémiologiques sur les infections fongiques dans les pays industrialisés ont été entreprises. C’est dans ce contexte que nous avons mené une étude épidémiologique de 2 infections fongiques chez les patients infectés par le VIH en France sur la French Hospital Database on HIV ANRS CO4 (FHDH) : la pneumocystose et l’aspergillose invasive. Concernant la pneumocystose, sur la période 2004-2011, dans la base FHDH, la moitié des 1259 cas de PCP étaient survenus chez des patients qui avaient interrompus leur suivi, et, pour ceux qui avaient déjà eu une IO avant la PCP, leur mortalité était de 25% à 3 ans. Pour l’aspergillose invasive (AI), après un retour national aux dossiers des cas déclarés sur 20 ans sur la base FHDH, un comité d’experts a validé 242 cas d’AI. Les données montrent que, chez les patients infectés par le VIH, seulement la moitié des AI validées répondaient aux critères EORTC. La mortalité à 3 mois après une AI s’est améliorée après l’ère des cART et un rôle protecteur du voriconazole sur la survie à 3 mois a également été démontré pour la 1ère fois chez les patients infectés par le VIH
The advent of combined antiretroviral therapy (cART) in 1996 resulted in a dramatic fall in the incidence of AIDS-defining illness (ADI), including Pneumocystis jirovecii pneumonia (PCP). Nevertheless, PCP was the second most frequent ADI in France in 2001-2003 and fungal infections remain a major threat for HIV-infected individuals worldwide. Epidemiological data on fungal infections in the late cART period in resource-rich settings are scarce. The purpose of our work was to study changes in the epidemiology of fungal infections among HIV-infected individuals in France in the late cART period, focusing on PCP and invasive aspergillosis (IA) in the French Hospital Database on HIV ANRS CO4 (FHDH). In the FHDH, during the 2004-2011 period, half of the 1259 PCP cases occurred among HIV-infected individuals who had waning adherence to care, and for those who had a prior ADI before PCP the 3-year mortality rate was 25%. For the second study on IA, a review committee validated IA cases among all the cases that included a diagnostic code for aspergillosis (ICD-9 or ICD-10) in the FHDH over a 20-year period. Our study demonstrated that only half of validated IA cases among HIV-infected individuals met EORTC criteria. The 3-months survival rate after IA diagnosis improved after the advent of cART and a protective role of voriconazole was observed in the period after 2001

Invasive fungal infections are prevalent and often deadly in immunocompromised patients. There continues to be a pressing need for the development of novel antifungal compounds since there are currently only 13 compounds licensed for the treatment of invasive fungal infections and antibiotic-resistant strains have been emerging. CAY-1 is an antifungal steroidal saponin which was isolated from the fruit of the cayenne pepper plant in 0.1% yield. In Vitro studies of CAY-1 have shown it to be an effective antifungal agent against sixteen pathogenic fungal strains and it showed no cytotoxicity toward mammalian cells up to 100 ìg/mL. The development of a practical synthesis of CAY-1 will potentially allow for further exploration of its medicinal utility and provide the opportunity to synthesize derivatives of CAY-1 which could be investigated in structure-activity relationship studies. To this end, methods for the preparation of they CAY-1 aglycone and pentasaccharide moieties have been investigated. Through this work, several partially protected stereoisomers of the CAY-1 aglycone have been prepared which can be used for the synthesis of saponin derivatives of CAY-1 for structure-activity relationship studies. Definitive characterization of one of these isomers, 3á-hydroxy-(22S, 25R)-5á-spirostan-2â-yl acetate, was achieved by X-ray crystallography. Furthermore, a quantitative inversion of the C-3 stereochemical configuration of this compound was achieved via an acetate group migration of the corresponding mesylate. The possibility of competition between the acetate migration and substitution mechanisms with various nucleophiles was explored. The results, however, indicate that this inversion only occurs via the acetate migration. Additionally, the CAY-1 pentasaccharide synthesis poses two significant challenges. First, these results demonstrate that the central 2, 3-branched portion can be synthesized efficiently from a partially protected glucopyranosyl acceptor since the C-2 and C-3 alcohols differ in their reactivity in glycosylation reactions. The second challenge is the ƒÀ-(1¨4) linkage to the galactosyl acceptor which significantly increases the complexity of the synthesis as compared to literature reported syntheses of other branched oligosaccharides. Nonetheless, this ƒÀ-(1¨4) linkage was achieved using a disarmed trichloroacetimidate glucosyl donor.

The overall aim of this thesis is to improve knowledge about the prevention of infectious and bleeding complications in patients with hematological malignancies, primarily in those with chronic lymphocytic leukemia (CLL) and myelodysplatic syndrome (MDS). Hypogammaglobulinemia, impaired production of immunoglobulins (Ig), is an established risk factor for infection, but the impact of IgG pure subclass deficiency (IgG subclass deficiency with adequate production of IgG, IgA, and IgM) has been debated. In a retrospective single institution study, we concluded that pure IgG subclass deficiency in CLL patients is rare and is not associated with an increased risk of infection. Hence, routine analysis of IgG subclasses in patients with CLL is not warranted. There is no consensus on recommending vaccination against Streptococcus pneumoniae to CLL patients mainly because comparative studies are lacking. In our randomized trial, the efficacy of a conjugated pneumococcal vaccine on immune response was superior or equal to a polysaccharide vaccine for all pneumococcal serotypes common for the two vaccines. A conjugate pneumococcal vaccine should therefore be included in vaccination programs for patients with CLL. Bronchoalveolar lavage (BAL) is a well-established invasive method to identify the cause of pulmonary infiltrates in immunocompromised patients. In a retrospective trial, we have studied the diagnostic yield of BAL in patients with hematological malignancies. We concluded that BAL is highly useful in either verifying or excluding some of the important respiratory tract infections affecting these patients, particularly invasive pulmonary aspergillosis (IPA) and Pneumocystis jirovecii pneumonia (PJP). However, standardized procedures for BAL sampling should be continually revised to avoid unnecessary microbiological tests. Thrombocytopenia, an adverse prognostic factor in patients with MDS, can be aggravated by azacitidine, first-line treatment for high-risk MDS. Eltrombopag, a thrombopoietin-receptor agonist (TPO-R), alleviates thrombocytopenia in patients with immune thrombocytopenic purpura (ITP). In a phase I clinical trial, we concluded that the combination of eltrombopag and azacitidine in high-risk MDS patients with thrombocytopenia is feasible and well tolerated in doses up to 200 mg eltrombopag daily.

Attention has begun to focus on the pulmonary delivery of antifungal agents for invasive fungal infections as inhalation of the fungal spores is often the initial step in the pathogenesis of many of these infections. Invasive fungal infection in the lungs in immunocompromised patients has high mortality rates despite current systemic (oral or intravenous) therapies. However, drug delivery of antifungal agents directly to the lungs could potentially result in high concentrations of drug in the lungs, a quicker onset of action, and reduction of systemic side effects. Voriconazole (VRC) is a second, generation triazole antifungal agent with increased potency, a broad spectrum of antifungal activity, and a fairly poor aqueous solubility. It is the recommended therapeutic agent for the treatment of Invasive Pulmonary Aspergillosis (IPA), and its use has improved therapeutic outcomes in immunocompromised patients with IPA. Still, systemic administration by oral or intravenous delivery is limited by high inter- and intra-patient pharmacokinetic variability, many potential drug interactions, and a narrow therapeutic index with many adverse effects, leading to clinical failures. Therefore, development of novel particulate formulations containing VRC for targeted drug delivery to the lungs is critical to improving therapeutic outcomes in patients with invasive fungal infections in the lungs. Within the framework of this dissertation, two particle engineering processes, thin film freezing (TFF) and advanced evaporative precipitation into aqueous solution (AEPAS), were investigated. The goal was to investigate microcrystalline VRC, nanocrystalline VRC, and nanostructured amorphous VRC formulations suitable for pulmonary delivery and to determine the effect of morphology on the in vivo deposition and distribution of inhaled particulate VRC formulations. TFF process parameters significantly affected the solid state properties and aerodynamic performance of the dry powder formulations containing VRC. Following dry powder insufflation into the lungs of mice, microstructured crystalline TFF-VRC achieved higher and more prolonged concentrations of VRC in the lungs with slightly lower systemic bioavailability than nanostructured amorphous TFF-VRC-PVP K25. AEPAS and TFF of template nanoemulsions did not lead to production of crystalline nanoparticles, as predicted. In particular, VRC proved to be a difficult molecule to stabilize in the nanocrystalline and nanostructured amorphous states. Ultimately, this body of work demonstrated that the particle engineering process, TFF, could be used to develop voriconazole formulations suitable for dry powder inhalation with more favorable pharmacokinetic parameters compared to inhaled voriconazole solution.
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Nos últimos anos verificou-se um aumento das infeções fúngicas invasivas, devido ao aumento da esperança de vida e do número de doentes imunodeprimidos e ao aparecimento de resistência aos antifúngicos. Durante muito tempo a terapêutica era limitada, utilizando-se na maior parte das vezes a anfotericina B. Apesar de ser bastante eficaz contra a maioria das infeções este fármaco apresenta efeitos colaterais consideráveis, em particular a nefrotoxicidade, o que limita o seu uso. Depois de algumas décadas surgiram novas classes terapêuticas: os azoís e posteriormente as equinocandinas, que demonstraram exercer menor toxicidade em humanos. De facto, a evolução científica tem permitindo o desenvolvimento de novos fármacos antifúngicos. As diretrizes na pesquisa destas novas moléculas são que estas possam ter maior eficiência, exercer menor toxicidade, tenham novos mecanismos de ação, menos interações medicamentosas e que possam ter atividade em novos agentes patogénicos emergentes. Esta dissertação destaca novas terapias em desenvolvimento clínico. Os fármacos em causa têm novos mecanismos de ação, de forma a superar as resistências, novas formulações com vantagens em relação às terapias atuais para melhorar os perfis de segurança e reduzir as interações. Os agentes referidos nesta revisão têm como alvo a parede celular (a rezafungina e ibrexafungerp) ou a membrana celular (a CAmB e o isavuconazol) havendo também um fármaco (olorofim) que apresenta um novo mecanismo de ação.
Over the past few years there has been an increase in invasive fungal infections, due to longer average lifespan, the number of immunocompromised patients and the appearance of resistance to antifungals. For a long time, therapy was limited, most of the time only using amphotericin B. Despite being quite effective against most infections, this drug has considerable side effects, in particular nephrotoxicity, which limits its use. After a few decades, have emerged new therapeutic classes : azois and later echinocandins, which have been shown to have less toxicity for humans. In fact, scientific progress allowed the development of new antifungal drugs. The guidelines for the research of these new molecules are that they can be more efficient, result in less toxicity, have new mechanisms of action, less drug interactions and have activity agaisnt new emerging pathogens. This dissertation emphasise new therapies in clinical development. The drugs in question have new mechanisms of action, in order to overcome resistance, new formulations with advantages over current therapies, to improve safety profiles and reduce interactions. The agents referred in this review target the cell wall (rezafungin and ibrexafungerp) or the cell membrane (CAmB and isavuconazole) and there is also a drug (olorophin) that has a new mechanism of action.

M. Tech. (Department of Biotechnology, Faculty of Applied and Computer Science), Vaal University of Technology|
Pigeon droppings, found in abundance in most cities and towns where pigeons are found, are a source of potential yeast and molds into the environment. Invasive fungal infections are a cause of morbidity and often mortality in immunocompromised individuals. The objective of this study was to the identification of bacterial and mold agents from pigeon droppings. Pigeon droppings samples were collected from three locations during the winter and summer months and studied for the occurrence of bacteria, yeast and molds by utilising culture-independent techniques. Amplification of the 16S rDNA gene and the internal transcribed spacer (ITS) region, cloning and ARDRA and DGGE were used for the characterisation of the microbial populations followed by sequencing. Several mold and yeasts, as well as bacteria were found to be present in pigeon droppings, which can spread into the environment and be transmitted to immunocompromised individuals and children. DGGE analysis of the bacterial communities revealed banding patterns that clustered all but one winter samples and all summer samples, showing a high similarity among the microbial members in both seasons and sample locations. Fungal DGGE analysis revealed clusters that grouped summer and winter samples from Johannesburg and Pretoria while VUT samples were clustered on their own. From the identification of fungal and bacterial DNA, Cryptococcus species was the majority of fungi isolated from the dropping samples. Geotrichum, Kazachstania and Fusarium species were isolated from phylotypes obtained from ITS amplicons analysed by ARDRA. Lactobacillus and Enteroccoccus species, organisms usually found in the gastrointestinal tract were the common bacterial members identified. The results showed no difference in microbial communities across all sample locations, while seasonal changes also had no impact in microbial community patterns.