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Petca, Răzvan-Cosmin, Silvius Negoiță, Cristian Mareș, Aida Petca, Răzvan-Ionuț Popescu, and Călin Bogdan Chibelean. "Heterogeneity of Antibiotics Multidrug-Resistance Profile of Uropathogens in Romanian Population." Antibiotics 10, no. 5 (2021): 523. http://dx.doi.org/10.3390/antibiotics10050523.
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Urinary tract infections (UTIs) are a leading cause of morbidity for both males and females. The overconsumption of antibiotics in general medicine, veterinary, or agriculture has led to a spike in drug-resistant microorganisms; obtaining standardized results is imposed by standard definitions for various categories of drug-resistant bacteria—such as multiple-drug resistant (MDR), extensive drug-resistant (XDR), and pan drug-resistant (PDR). This retrospective study conducted in three university teaching hospitals in Romania has analyzed urine probes from 15,231 patients, of which 698 (4.58%) presented multidrug-resistant strains. Escherichia coli was the leading uropathogen 283 (40.54%), presenting the highest resistance to quinolones (R = 72.08%) and penicillin (R = 66.78%) with the most important patterns of resistance for penicillin, sulfonamides, and quinolones (12.01%) and aminoglycosides, aztreonam, cephalosporins, and quinolones (9.89%). Klebsiella spp. followed—260 (37.24%) with the highest resistance to amoxicillin-clavulanate (R = 94.61%) and cephalosporins (R = 94.23%); the leading patterns were observed for aminoglycosides, aminopenicillins + β-lactams inhibitor, sulfonamides, and cephalosporins (12.69%) and aminoglycosides, aztreonam, cephalosporins, quinolones (9.23%). The insufficient research of MDR strains on the Romanian population is promoting these findings as an important tool for any clinician treating MDR-UTIs.
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Немченко, Ulyana Nemchenko, Григорова, et al. "analysis of phago- and antibiotic sensitivity of Enterobacteriaceae bacteria isolated from women of reproductive age." Бюллетень Восточно-Сибирского научного центра Сибирского отделения Российской академии медицинских наук 1, no. 5 (2016): 150–54. http://dx.doi.org/10.12737/23414.
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Pelvic inflammatory diseases occupy a special place in the structure of general morbidity, and are polymicrobial in nature with dominance of opportunistic microorganisms, in particular bacteria of the family Enterobacteriaceae.The aim was to study the composition of the vaginal microbiota in women of reproductive age with pelvic inflammatory diseases, as well as to determine the sensitivity of isolated microorganisms to antibiotics and bacteriophages.The study included 70women of reproductive age, among them 37were diagnosed with colpitis and cervicitis, 33women in the comparison group (women screened for a diagnosis). Isolated microorganisms were identified by abdominoperineal methods, including the disk diffusion method to determine the sensitivity of microorganism cultures of Enterobacteriaceae family to antibiotics, and the method of crosses (evaluation of lytic activity of bacteriophages by the number of crosses) to determine the sensitivity to specific therapeutic bacteriophages.Vaginal biocenosis was characterized by deficit of lactobacilli (<106CFU/ml in 100%), the presence of conditionally pathogenic microflora: bacteria of Enterobacteriaceae family, coccal flora and Candida fungi. From 60.0 to 89.3% of Enterobacteria strains were resistant to aminoglycosides and quinolones, but also had a low level of sensitivity to therapeutic bacteriophages.The obtained data indicate the reduction of colonization resistance of vaginal mucosa in pelvic inflammatory diseases and specify the need to use medicinal drugs only under medical supervision to prevent clinically significant drug resistance.
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CHARTERIS, WILLIAM P., PHILLIP M. KELLY, LORENZO MORELLI, and J. KEVIN COLLINS. "Effect of Conjugated Bile Salts on Antibiotic Susceptibility of Bile Salt–Tolerant Lactobacillus and Bifidobacterium Isolates." Journal of Food Protection 63, no. 10 (2000): 1369–76. http://dx.doi.org/10.4315/0362-028x-63.10.1369.
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Virtually every antibiotic may cause in vivo alterations in the number, level, and composition of the indigenous microbiotae. The degree to which the microbiotae are disturbed depends on many factors. Although bile may augment antibiotic activity, studies on the effect of bile on the antibiotic susceptibility of indigenous and exogenous probiotic microorganisms are lacking. It was against this background that the antibiotic susceptibility of 37 bile salt–tolerant Lactobacillus and 11 Bifidobacterium isolates from human and other sources was determined in the presence of 0.5% wt/wt oxgall (conjugated bile salts). Oxgall did not affect the intrinsic resistance of lactobacilli to metronidazole (5 μg), vancomycin (30 μg), and cotrimoxazole (25 μg), whereas it resulted in a complete loss of resistance to polymyxin B (300 μg) and the aminoglycosides gentamicin (10 μg), kanamycin (30 μg), and streptomycin (10 μg) for most strains studied (P < 0.001). Oxgall did not affect the intrinsic resistance of bifidobacteria to metronidazole and vancomycin, whereas polymyxin B and co-trimoxazole resistance was diminished (P < 0.05) and aminoglycoside resistance was lost (P < 0.001). Seven lactobacilli, but no bifidobacteria strain, showed unaltered intrinsic antibiotic resistance profiles in the presence of oxgall. Oxgall affected the extrinsic susceptibility of lactobacilli and bifidobacteria to penicillin G (10 μg), ampicillin (10 μg), tetracycline (30 μg), chloramphenicol (30 μg), erythromycin (15 μg), and rifampicin (5 μg) in a source- and strain-dependent manner. Human strain–drug combinations of lactobacilli (P < 0.05) and bifidobacteria (P < 0.01) were more likely to show no change or decreased susceptibility compared with other strain-drug combinations. The antimicrobial activity spectra of polymyxin B and the aminoglycosides should not be considered limited to gram-negative bacteria but extended to include gram-positive genera of the indigenous and transiting microbiotae in the presence of conjugated bile salts. Those lactobacilli (7 of 37) that show unaltered intrinsic and diminished extrinsic antibiotic susceptibility in the presence of oxgall may possess greater upper gastrointestinal tract transit tolerance in the presence of antibiotics.
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Souza, Teógenes, Maria Morais-Braga, José Costa, Antônio Saraiva, and Henrique Coutinho. "Enhancement of antimicrobial activity of antibiotics and antifungals by the use of natural products from Pityrogramma calomelanos (L.) link." Archives of Biological Sciences 64, no. 1 (2012): 43–48. http://dx.doi.org/10.2298/abs1201043s.
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The ethanol extract and methanol fraction of Pityrogramma calomelanos (L.) link were evaluated for antibacterial, antifungal and modulatory activities against strains of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, C. krusei and C. tropicalis. The antimicrobial activity of the natural products was evaluated by the microdilution method associated or not with aminoglycosides and antifungals. The ethanol extract and methanol fraction of P. calomelanos showed good activity against S. aureus when associated with aminoglycosides and with benzoilmetronidazol against species of the genus Candida. These results indicate that P. calomelanos should be studied as a possible source of natural products to combat bacteria and fungi either directly or by modulating the mechanisms of resistance of these microorganisms, enhancing the antimicrobial activity of these drugs and combating microbial resistance.
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Golovko, A. M., N. G. Pinchuk, T. I. Fotina, and Zh E. Klishchova. "Determination of bactericidal properties of the drug “Saroflox” in relation to museum test cultures of microorganisms." Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 21, no. 95 (2019): 89–92. http://dx.doi.org/10.32718/nvlvet9516.
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Everyone knows that test cultures are used to control and quality the growth properties of nutrient media, to check the activity of antiseptics and disinfectants, as well as to assess the adequacy of the sensitivity of the tested microorganisms to new antibacterial drugs, which are currently produced by rapid temp. with the development of antibiotic resistance of microorganisms to most of the active substances used in new drugs. Moreover, it is the understanding that most antibiotics are clinically useless in treating infectious diseases because of their long-term use for chemotherapy purposes – a major problem not only in Ukraine but worldwide. In this article the results of researches sensitivity museum strains, namely: Escherichia coli ATCC 25922 (F-50), Pseudomonas aeruginosa ATCC 2853 (F), Proteus vulgaris HX 19 number 222, Staphylococcus aureus ATCC 25923, Enterobacter aerogenes 10006, Enterococcus faecalis ATCC 19433 to the antibacterial drug “Saroflox”. We find that Saroflox inhibited the growth of all test cultures at different dilution rates. Using different concentrations of the antibiotic (2.5 mg, 1.25 mg, 0.625 mg, 0.3125 mg, 0.1562/200 μl), it was found that all test cultures under study were highly sensitive to Saroflox. most from 38.0 ± 1.0 to 20.0 ± 1.0 mm. The results of studies show that the new antibacterial drug “Saroflox” has bactericidal properties to most cultures that cause bacterial diseases of various species of animals and birds, which only confirms its effectiveness against gram-negative microorganisms (Enterobacter spp. , Staphylococcus aureus E. coli and others) including beta-lactam antibiotic resistant, tetracyclines, macrolides and aminoglycosides.
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García-Méndez, Jorge, Erika M. Carrillo-Casas, Andrea Rangel-Cordero, et al. "Nocardia transvalensisDisseminated Infection in an Immunocompromised Patient with Idiopathic Thrombocytopenic Purpura." Case Reports in Infectious Diseases 2016 (2016): 1–3. http://dx.doi.org/10.1155/2016/3818969.
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Nocardia transvalensiscomplex includes a wide range of microorganisms with specific antimicrobial resistance patterns. N. transvalensisis an unusualNocardiaspecies. However, it must be differentiated due to its natural resistance to aminoglycosides while otherNocardiaspecies are susceptible. The present report describes aNocardiaspecies involved in an uncommon clinical case of a patient with idiopathic thrombocytopenic purpura and pulmonary nocardiosis. Microbiological and molecular techniques based on the sequencing of the 16S rRNA gene allowed diagnosis ofNocardia transvalensissensu stricto. The successful treatment was based on trimethoprim-sulfamethoxazole and other drugs. We conclude that molecular identification ofNocardiaspecies is a valuable technique to guide good treatment and prognosis and recommend its use for daily bases diagnosis.
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V. A., Mochonyi, Savchenko O. A., Podsevakhina S. L., and Tkachenko O. V. "PROBLEMS OF THE TREATMENT OF PNEUMONIA CAUSED BY PSEUDOMONAS AERUGINOSA." Modern medical technologies 42, no. 3 (2019): 78–83. http://dx.doi.org/10.34287/mmt.3(42).2019.15.
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Pseudomonas infection is one of the most problematic pathogens of pneumonia, because it has natural resistance to many antibiotics, is able to quickly form acquired resistance, often causes severe pneumonia with a poor prognosis. Analysis of the literature data showed that today P. Aeruginosa demonstrates resistance to all anti-pest control antibiotics, with the exception of polymyxin. The levels of resistance of P.Aeruginosa are very considerably depending on the region of the survey and the profile of the hospital, which requires monitoring the sensitivity of microorganisms in each department of the hospital. The data on the degree of resistance to P. Aeruginosa antibiotics in Ukraine are limited, but available local studies on this issue also show a high level of resistance of this microorganism to the main anti-pest antibiotics. In patients with pneumonia and risk factors for the involvement of Pseudomonas infection, most authors recommend combination antibiotic therapy, which has a synergistic effect on P. Aeruginosa, which allows, in most cases, to overcome the resistance of this microorganism. According to the literature, such synergism has been proven for the combination: beta-lactams (ceftazidime, cefepime, antipseudomonas carbapenems) + aminoglycosides (amikacin) or fluoroquinolones (ciprofloxacin or levofloxacin). The use of these drugs in the maximum allowable dose allows a higher degree of probability to achieve the eradication of P. Aeruginosa in patients with pneumonia and to improve the prognosis for this disease. Keywords: pneumonia, Pseudomonas Aeruginosa, resistance, treatment.
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Pkhakadze, Tamara Yakovlevna, G. G. Okropiridze, E. S. Malysheva, T. Ya Pkhakadze, G. G. Okropiridze, and E. S. Malysheva. "Choice of Antibacterial Agents for Prevention and Treatment of Infectious Complications in Traumatologic and Orthopaedic Patients by Microbiologic Monitoring." N.N. Priorov Journal of Traumatology and Orthopedics 16, no. 4 (2009): 73–78. http://dx.doi.org/10.17816/vto200916473-78.
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Etiologic structure of infectious complications in traumatologic and orthopaedic patients has been studied at CITO named after N.N. Priorov during the period from 2005 to 2007. Using modern agents and techniques 6799 samples from 3023 patients were studied. Resistance of pathogenic microorganisms to the wide spectrum of antibiotics including the drugs of last gene-ration was studied. Basing on the study results the protocols for the application of modern antibiotics including protected aminopeptides, cephalosporins of third-forth generation including the protected ones, glycopeptides, oxazolidinones, aminoglycosides, fluoroquinolones, carbape-nemones have been elaborated and introduced into clinical practice.
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Ahsan, ASM Areef, Lovely Barai, Mohammad Omar Faruq, et al. "Antibiotic Resistance Pattern among Bacteria causing Ventilator Associated Pneumonia in An Intensive Care Unit of Bangladesh." Bangladesh Critical Care Journal 4, no. 2 (2016): 69–73. http://dx.doi.org/10.3329/bccj.v4i2.30019.
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Background : Ventilator-associated pneumonia (VAP) is the most common type of nosocomial infection in critical care practice with high morbidity and mortality. Microorganisms responsible for VAP vary from place to place. So, identification of causative organism and knowledge of their resistance pattern is very important for empirical choice of antibiotic in managing VAP. The aim of this survey was to evaluate the quantitative cultures of endotracheal aspirates to determine the microorganisms responsible for VAP and to study their antibiotic resistance pattern.Materials and Methods: This cross sectional study was performed over a period of six month starting from November, 2015 to April, 2016 in the Intensive Care Unit (ICU) of BIRDEM General Hospital. Patients with a clinical and radiological diagnosis of VAP were included in this study.Result: A total of 51 patients with a clinical diagnosis of VAP were included in this study. Growth was obtained in100% of the samples yielding 88 organisms. Gram-negative organisms were the mostly isolated organism (76.13%), followed by fungi (17.04%) and gram-positive cocci (6.81%). The most common pathogen was Acinetobacter sp. followed by Klebsiella sp., Candida sp. and Pseudomonas sp. respectively. Among the gram negative organisms, Acinetobacter sp., Klebsiella sp. and Pseudomonas sp. were highly resistant (>80%) to third generation cephalosporins and fluoroquinolones. Resistance to aminoglycosides (>68%) and imipenem (>60%) was also high. Resistance of Pseudomonas sp. to piperacillin-tazobactum was lower (18.2%) in comparison to Acinetobacter sp. and Klebsiella sp. All the Gram-negative organisms were 100% sensitive to colistin except proteus. Regarding gram-positive cocci,Staphylococcus aureus is 100% sensitive to netilmycin and vancomycin with variable resistance pattern to other antibiotics.Conclusion: Emergence of drug resistance against the microorganism causing VAP is a serious concern in most of the ICUs. A knowledge of antibiotic susceptibility pattern will avoid its irrational use in order to control the spread of infection and for proper management of VAP.Bangladesh Crit Care J September 2016; 4 (2): 69-73
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AL-Khikani, Falah Hasan. "Antimicrobial Resistance Profile Among Major Bacterial Pathogens in Southern Babil, Iraq." Galician Medical Journal 27, no. 3 (2020): E202036. http://dx.doi.org/10.21802/gmj.2020.3.6.
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Background: At present, drug-resistant pathogens are considered one of the major increasing causes of morbidity and mortality around the world. The data on microorganisms' resistance assist define the best available treatment for patients. Therefore, this study aimed to screen the antimicrobial-resistant profile of different drugs in major clinical pathogens of urine, ear and wound infections.
Methods: This study was conducted in Al-Shomali General Hospital, Southern Babil, Iraq from October 2019 to May 2020. Totally 67 clinical specimens obtained from the wound, urine, and ear discharge collected from hospitalized patients as well as 30 healthy individuals participate in this study. Then, the standard microbiological methods carried outperformed to the isolated and identified bacterial species. Antimicrobial susceptibility tests were performed using different antimicrobial discs by applying the Kirby–Bauer disc diffusion method.
Results: Totally, 67 bacterial isolates were obtained from 44 (66%) female and 23 (34%) male patients. Staphylococcus aureus and E. coli were the most common predominant organisms. All isolates were showed a high rate of resistance to evaluated cephalosporins 100% and 87% to cefotaxime and ceftriaxone respectively, while very low resistance recorded in Aminoglycosides 22% and 12% to Gentamicin and amikacin, respectively.
Conclusion: These results suggest a constant screening for the detection of antibiotic resistance, as well as developing antimicrobial stewardship programs in Babil, Iraq. Moreover, these bacterial isolates have shown multidrug resistance, mainly to commonly administered drugs that could cause therapy ineffective. Therefore, in clinical use, appropriate treatment should be chosen based on the results obtained from antimicrobial susceptibility tests.
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Barriuso, Jorge Bárcena, Deivid Roni Ribeiro, Javier Felipe Burchard, et al. "Characterization and in vitro susceptibility profile of bacterial samples harvest from canine chronic otitis." Medicina Veterinária (UFRPE) 15, no. 2 (2021): 110–18. http://dx.doi.org/10.26605/medvet-v15n2-4396.
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This study aimed to identify which are the most frequent bacteria evolved in cases of chronic otitis in dogs in the metropolitan region of Curitiba, as well to determine their in vitro antimicrobial susceptibility. Data of positive bacterial culture from dogs affected by chronic or recurrent otitis were compiled from the records of the veterinary hospital of Pontifícia Universidade Católica do Paraná, Curitiba, southern Brazil. In a period of 16 months, a total of 83 bacterial cultures were performed, resulting in 192 isolates. All isolates were submitted to antimicrobial susceptibility tests, based on the Kirby-Bauer technique using 17 drugs from 8 antibiotic classes (?-lactams, aminoglycosides, lincosamides, macrolides, polypeptides, quinolones, tetracyclines, and amphenicols). The five most frequent bacterial isolates were Staphylococcus spp. (58.32%), Proteus spp. (14.58%), Escherichia coli (9.90%) and Pseudomonas spp. (8.33%). The four most effective antibiotics were amikacin (13.29%), neomycin (24.47%), gentamicin (25.52%) and tobramycin (26.70%); however, these aminoglycosides may cause ototoxicity, and their use should be restricted when the tympanic membrane is intact. Quinolones also showed antimicrobial effectiveness, with 29.17% of the isolates showing resistance to ciprofloxacin and 29.69% to enrofloxacin. According to the results, it can be concluded that aminoglycosides and quinolones were effective against microorganisms of canine chronic otitis.
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Gajbhiye, Varsha P., and Lamture Y. R. "Drug utilization pattern of antimicrobials use in upper respiratory tract infection in paediatric patient of rural tertiary care hospital." International Journal of Basic & Clinical Pharmacology 8, no. 1 (2018): 74. http://dx.doi.org/10.18203/2319-2003.ijbcp20185161.
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Background: Antimicrobial agents (AMAs) are most commonly prescribed drugs for lower respiratory tract infection (LRTI). This study was conducted to evaluate pattern of prescription and AMAs use in paediatric patient for LRTI in wards of rural tertiary care teaching hospital.Methods: This is prospective, observational study undertaken in paediatric patient in tertiary care hospital. Prescriptions of 60 patient of age group 1-12years diagnosed with LRTI admitted in paediatric ward of rural tertiary care teaching hospital were studied. Positive blood sample were studied for common microorganisms, their sensitivity and resistance to AMAs.Results: Out of 60 patients admitted in paediatric ward of LRTI, 12 patients were of mild to moderate pneumonia, three patients were of bronchiolitis, ten patients were of croups, three patients were of bronchitis and 37 patients were of severe pneumonia. The most frequently prescribed AMAs were combination of cephalosporin and aminoglycosides. The most common organism isolated was streptococcus pneumoniae sensitive to vancomycin in 92.3% and meropenem in 84.6%, resistant to ampicillin, amoxicillin and cloxacillin in 92.3% of cases.Conclusions: The study shows utilisation pattern of AMAs in LRTI, prescribing on which future intervention studies may be based to promote rational drug use.
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Mitache, Mihaela Magdalena, Otilia Banu, Elvira Borcan, et al. "Resistance and Virulence Patterns in Gram Negative and Gram Positives Rods Isolated from the Hospital Environment in Bucharest, Romania." Revista de Chimie 69, no. 11 (2018): 3126–32. http://dx.doi.org/10.37358/rc.18.11.6697.
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We aimed to investigate the antibiotic resistance�and virulence�markers in�Gram negative bacilli (GNB) and Gram positives coccus (GPC), strains recently isolated from the�hospital environment and from patients with surgical wound infections in order to obtain epidemiologically relevant data.The strains identification was performed with�the automated miniApi system. The resistance�phenotypes were established�using disk diffusion (CLSI, 2017). 61 strains were screened for the production of enzymatic soluble virulence factors: hemolysins, amylase, caseinase, aesculin hydrolysis, DNA-ase, lipase, gelatinase and lecithinase, which give microorganisms the ability to colonize and disseminate in the host. Multiplex PCR reactions were performed for the detection of carbapenemases, aminoglycoside-resistant determinants (AME�s), quinolone and tetracycline resistance in GNR and SCCmec cassette type in�Staphylococcus aureus�strains and�to identify the genetic�support of cell-associated�and soluble virulence factors�in�E. coli�strains�(fimH, sfaDE, papC, eaea, cnf1, bfpa, eaf, AggR, EaggE�genes) and biofilm production in Acinetobacter baumannii isolates (OmpA).The isolated�E. coli and A. baumannii strains were resistant to �-lactam antibiotics, including penicillins and beta-lactamase inhibitors, third / fourth generation cephalosporins and carbapenems (encoded by�blaOXA-48like�and blaTEMlike genes), quinolones (qnrA and qnrB), aminoglycosides�(aadB), and�tetracyclines (encoded by tetA and tetB). Most of the strains presented at least two of the eight tested virulence factors.�The carbapenemases and ESBLs producers proved to be positive for the majority of the tested soluble virulence factors, proving the pathogenic potential of these strains. In�S. aureus�isolates�the molecular analysis showed that 60% of the isolates were MRSA and the molecular analysis revealed the presence of the SCCmec cassette type�mec IVa and III types. Our data suggest the hypothesis according to which nosocomial origin of the strains can be explained by multiple drug resistance and virulence determinants.
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Kotsyuba, K. R., O. S. Voronkova, A. І. Vіnnіkov та T. M. Shevchenko. "Механізми стійкості до антибіотиків представників родини Enterobacteriaceae". Visnyk of Dnipropetrovsk University. Biology, medicine 5, № 1 (2014): 33–38. http://dx.doi.org/10.15421/021407.
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The paper deals with the basic medical scheme of antibiotics use for treatment of lesions caused by enterobacteria and mechanisms of resistance of Enterobacteriaceae to different classes of antibiotics. It is known that the main mechanisms of resistance to antibiotics are enzymatic inactivation, modification of the target, efflux, violation of conduct through the membrane and formation of metabolic shunt. The most common cases of resistance to beta-lactams among Enterobacteriaceae relate to production of plasmid and chromosomal beta-lactamases, violation of the permeability of the outer membrane, and modification of target penicillin binding proteins. Active release of antibiotics from the cell, or efflux, in Enterobacteriaceae is used for maintaining resistance to tetracyclines, macrolides, carbapenems. Genes of efflux system are localized on plasmids and contribute to rapid spreading among Enterobacteriaceae. Mutations are the basis of resistance to novobiocinum and rifampicinum. Enzymatic inactivation by modifying is typical for resistance to aminoglycosides. Three groups of enzymes are engaged in the process, by adding the molecule of acetic acid, phosphate or adenine. Joining of these groups is irreversible and leads to complete loss of biological activity of the antibiotic. Resistance to aminoglycosides appears also due to inhibition of drug penetration, that is associated with genetically determined mechanisms of electron transport through the membrane. Resistance to quinolones and fluoroquinolones is associated with the modification of topoisomerase II and IV which are targets of these groups of antibiotics. Resistance is possible as a result of changes in the structure of the target, breaching of penetration into the cell, and active release from the cell. The highest level of resistance is develope in the case of two- or three-stage mutations in one or the other, or both, subunits in different genes. At the same time, for breaching of the bacterial cell it is enough to suppress the activity of only one enzyme associated with different functions of both topoisomerases. Another mechanism of resistance to quinolones is the reduction of permeability through bacterial outer membrane, that it’s possible due to decreasing of permeability of porine channels. In this case, decreasing of permeability efficacy takes place not only for quinolones, but also for other classes of antibitics. In addition, reduced sensitivity to quinolones efflux may play the significant role. For clinical strains of microorganisms, cross-resistance to various drugs, associated with simultaneous production of various enzymes that inactivate antibiotics, is typical.
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Nazarchuk, O. A., A. I. Starodub, O. V. Rymsha, V. A. Starodub, and S. A. Kolodii. "Characteristics of the etiological structure and susceptibility to antibiotics, antiseptics of infectious pathogens of respiratory organs in children in critical states." Reports of Vinnytsia National Medical University 22, no. 2 (2018): 311–17. http://dx.doi.org/10.31393/reports-vnmedical-2018-22(2)-16.
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The study of the etiological structure, the properties of pathogens of the respiratory infectious diseases in children and their resistance to antibacterial agents is particularly relevant in modern conditions, expands the search for new approaches to combating pathogens, improves the results of treatment and reduces the mortality of this pathology. The aim — study of etiological structure, sensitivity to antibiotics and antiseptics of pathogens of infectious and inflammatory diseases of respiratory organs in children. In the study there were enrolled 247 patients who were treated in Vinnytsia Regional Children’s Clinical Hospital (VRCCH) in 2016. The sensitivity of microorganisms to 23 antibacterial agents was determined by the disc-diffusion method according to the generally accepted method. The analysis of the antimicrobial activity of antiseptic drugs (decamethoxine, miramistin, chlorhexidine digluconate) was performed by a double serial dilution technique with the determination of the minimum inhibitory bacteriostatic (MIC) and bactericidal (MBcC) concentrations, by the method of successive serial dilutions of the drug in a liquid nutrient medium. In patients who were in inpatient treatment at the VRCCH in 2016 because of pneumonia there were found opportunistic microorganisms which were of etiological significance in the development of the infection. Among them there were Streptococci (47,3 %), Staphylococci (15,3 %), Candida (13,3 %), Enterococci (10,9 %), including a high proportion of owned non-fermenting gram negative bacilli (9,8%) and species of Enterobacteria (2,0 %). Isolated strains of microorganisms had moderate resistance to most modern antibiotic drugs. The sensitivity of isolated strains of microorganisms to reserved antibiotics as carbapenems, often being used in the treatment of critical states of patients in the intensive care units, was found to above 18,2%. The sensitivity to this antibiotic in Enterococcus spp. (7,1 %), Staphylococcus spp. (5,9 %) was also low. Carbapenems, fluoroquinolones (the 1st and 2nd generations), antibiotics and aminoglycosides were found to be effective against gram positive microorganisms in more then 45% of cases. According to this they were considered to be as drugs of choice in the treatment of infectious and purulent-inflammatory pathology of respiratory organs, caused metitcilin- and vancomycin-resistant strains of microorganisms. Resistance to these drugs among investigated strains did not exceed 9,0 %. The high bactericidal properties of antiseptics as decamethoxine was determined against S.pyogenes, Staphylococcus spp. Its MBcC against these bacteria (1,65±0,20 mkg/ml and 4,32±0,50 mkg/ml, respectively) proved the advantage of decamethoxine’s effectiveness in comparison with chlorhexidine digluconate 3,14 times, 2,44 times miramistin. Clinical strains of C.albicans showed the highest susceptibility to decamethoxine, which fungicidal activity was determined in the presence (16,17±2,33 mkg/ml), in comparison with chlorxedine (MFtsK 27,59±3,59 mg/ml) and miramistin activity (27,59±3,595 mkg/ml). In children with inflammatory diseases of the respiratory organs gram-positive cocci are among the predominant pathogens (73,5 %) of cases, in the association allocated – 8,0 % of pathogens. Allocated strains of microorganisms were moderately resistant to all antibiotics studied. For antimicrobial activity antiseptic drugs, especially decamethoxine, have advantages over antibiotics confirming the possibility of their use in combination with systemic antibacterials.
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Shipitsyna, I. V., E. V. Osipova, O. A. Astashova, and D. S. Leonchuk. "Monitoring of the leading causative agents of osteomyelitis and their antibiotic resistance." Russian Clinical Laboratory Diagnostics 65, no. 9 (2020): 562–66. http://dx.doi.org/10.18821/0869-2084-2020-65-9-562-566.
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The annual monitoring of the species composition of the causative agents of osteomyelitis, the identification of antibiotic-resistant strains, the study of the species composition of associations of microorganisms, their adhesive activity will prevent the spread of infection. Analyze the spectrum of the leading causative agents of osteomyelitis, their antibiotic sensitivity, and also the adhesive activity of the identified bacterial associations. A microbiological analysis of 2197 smears of adult patients with various etiological forms of osteomyelitis who were treated in the departments of the purulent center of the FSBI «NMRCTO» of the RF Ministry of Health in 2019. The spectrum of pathogenic microflora, sensitivity to standard antibacterial drugs used in the clinic was studied. The biofilm-forming ability of associations of microorganisms was investigated. According to the conducted microbiological monitoring for 2019, the microflora spectrum for osteomyelitis is diverse, the main pathogens are S. aureus, S. epidermidis, P. aeruginosa, K. pneumoniae, Enterococcus sp. A high percentage of isolation of microbial associations was noted, most often mix cultures of gram-positive and gram-negative bacteria. Bacterial associations: S. aureus + P. aeruginosa, S. aureus + S. marcescens, S. aureus + A. baumannii, S. epidermidis + E. cloacae - actively formed a biofilm on the surface of polystyrene plates, and the adhesive potential depended on interstrain relations in the composition of the formed biofilm. Among Gram-negative microflora, multiresistant strains prevail, among Gram-positive microflora - a high percentage of methicillin-resistant Staphylococci. When analyzing the antibiotic sensitivity of the isolated microorganisms, a high percentage of resistant strains is noted. So, with respect to enterobacteria, β-lactam antibiotics, drugs from the group of aminoglycosides, turned out to be ineffective. Among non-fermenting gram-negative bacteria, A. baumannii strains had multiple antimicrobial resistance. Among gram-positive microorganisms, a high percentage of isolation of methicillin-resistant staphylococci was noted. The specificity of the course of the disease and measures aimed at eliminating the pathogen depend on the species composition in the focus of infection. The study of the etiological structure of osteomyelitis, the monitoring of the antibiotic resistance of pathogens and their persistent potential, makes it possible to adopt sound tactics of conservative and surgical treatment.
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Kotov, S. V., S. A. Pulbere, S. V. Belomyttsev, R. A. Perov, N. V. Alesina, and E. A. Zheltikova. "Antibiotic resistance – a new challenge of modern urology." Experimental and Сlinical Urology 13, no. 5 (2020): 113–19. http://dx.doi.org/10.29188/2222-8543-2020-13-5-113-119.
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Introduction. Analyze of the incidence and resistance to antibacterial drugs to microorganisms isolated in urine cultures of patients with urinary tract infections (UTI) from 2012 to 2019. Materials and methods. In the clinic of urology clinical hospital № 1 named after N.I. Pirogov and in the city clinical hospital № 29 named after N.E. Bauman was analyzed the results of 6083 urine cultures in 5027 patients. The traditional standardized inoculation was carried out with a 10 μl loop on the following nutrient media: agar with the addition of 5% sheep blood (Pronadisa, Spain), Levin agar (Pronadisa, Spain), Biggie agar (BD, USA), followed by incubation at 37°C for 18-24 hours. Next, a visual colony count was performed. The sensitivity of the isolated microorganisms to antibiotics was evaluated using a Phoenix bacteriological analyzer (BD, USA) and a disk diffusion method production discs (BD, USA). ESBL producers and carbapenemases were evaluated using a Phoenix bacteriological analyzer (BD, USA) using the double disc method, by the method of inactivation of carbapenems. Results. A high level of resistance among Enterococcus faecalis strains to fluoroquinolones (> 20%) and aminoglycosides (> 35%) was revealed. Among the strains of Escherichia coli, an increase in resistance to the antibacterial group of penicillins (> 80%) was noted, at the same time, an increase in resistance to drugs of the cephalosporins group (> 60%), fluoroquinolones (> 50%) was observed. The appearance of carbapenem-resistant strains is noted. Among the strains of Klebsiella pneumonia, high resistance to fluoroquinolones (> 50%) and cephalosporins (> 45%) was found. A sharp increase in resistance to all used antibacterial drugs is noted. Separately, increase in resistance to carbapenems (27,1%) can be noted. Discussion. According to the results of our study, it can be argued that the most common causative agents of complicated UTI in 2019 were representatives of the Enterococcaceae and Enterobacteriaceaes, there is an increase in the number of strains resistant to certain groups of antibacterial drugs. When comparing the results obtained with the data of the Internet platform «Map of antibiotic resistance. AMR map» shows comparable data on the occurrence and resistance of microorganisms. Of particular concern is the high frequency of bacterial resistance to drugs of the fluoroquinolone group and, therefore, these drugs cannot be used as empirical therapy for patients with complicated UTI. Conclusions. Adhering to the strategy of rational antibiotic therapy, further studying of the problem of antibiotic resistance, identification of resistant strains, monitoring of the of antibacterial drugs prescription at the outpatient stage and in the hospital are necessary. It is necessary to study the epidemiological data and the results of susceptibility to antibiotics in a particular region, this will help us to more accurately select antibiotic therapy and introduce accelerated laboratory diagnosis of bacteria resistance markers into practice.
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Kyriakidis, Ioannis, Eleni Vasileiou, Zoi Dorothea Pana, and Athanasios Tragiannidis. "Acinetobacter baumannii Antibiotic Resistance Mechanisms." Pathogens 10, no. 3 (2021): 373. http://dx.doi.org/10.3390/pathogens10030373.
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Acinetobacter baumannii is a Gram-negative ESKAPE microorganism that poses a threat to public health by causing severe and invasive (mostly nosocomial) infections linked with high mortality rates. During the last years, this pathogen displayed multidrug resistance (MDR), mainly due to extensive antibiotic abuse and poor stewardship. MDR isolates are associated with medical history of long hospitalization stays, presence of catheters, and mechanical ventilation, while immunocompromised and severely ill hosts predispose to invasive infections. Next-generation sequencing techniques have revolutionized diagnosis of severe A. baumannii infections, contributing to timely diagnosis and personalized therapeutic regimens according to the identification of the respective resistance genes. The aim of this review is to describe in detail all current knowledge on the genetic background of A. baumannii resistance mechanisms in humans as regards beta-lactams (penicillins, cephalosporins, carbapenems, monobactams, and beta-lactamase inhibitors), aminoglycosides, tetracyclines, fluoroquinolones, macrolides, lincosamides, streptogramin antibiotics, polymyxins, and others (amphenicols, oxazolidinones, rifamycins, fosfomycin, diaminopyrimidines, sulfonamides, glycopeptide, and lipopeptide antibiotics). Mechanisms of antimicrobial resistance refer mainly to regulation of antibiotic transportation through bacterial membranes, alteration of the antibiotic target site, and enzymatic modifications resulting in antibiotic neutralization. Virulence factors that may affect antibiotic susceptibility profiles and confer drug resistance are also being discussed. Reports from cases of A. baumannii coinfection with SARS-CoV-2 during the COVID-19 pandemic in terms of resistance profiles and MDR genes have been investigated.
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Srivastava, Parul, Yogesh B. Khandokar, and Jade K. Forwood. "Purification, crystallization and preliminary X-ray diffraction analysis of theN-acetyltransferase SAV0826 fromStaphylococcus aureus." Acta Crystallographica Section F Structural Biology Communications 70, no. 2 (2014): 211–14. http://dx.doi.org/10.1107/s2053230x13034493.
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Staphylococcus aureusis a prevalent microorganism that is capable of causing a wide range of infections and diseases. Several strains of this bacterial species have developed antibiotic resistance to methicillin and vancomycin, and higher death rates are still being reported each year owing to multidrug-resistant strains. Certain GCN5-relatedN-acetyltransferases (GNATs) exhibit a broad substrate range, including aminoglycosides, histones, other proteins and serotonin, and have been implicated in antibiotic drug resistance. Here, the expression, purification, crystallization and preliminary X-ray diffraction analysis of a GNAT fromS. aureus(SaNAT) are reported. SaNAT was recombinantly expressed and crystallized by the hanging-drop vapour-diffusion method at 296 K, and the crystals diffracted to 1.7 Å resolution on the MX2 beamline at the Australian Synchrotron. The crystals belonged to space groupP43212, with unit-cell parametersa=b= 84.86,c= 49.06 Å, α = β = γ = 90°. A single molecule is likely to be present in the asymmetric unit. A full structural and functional analysis is currently being undertaken to provide novel insights into the protein function, which in turn may provide a basis for drug design.
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Salipante, Stephen J., Miriam Barlow, and Barry G. Hall. "GeneHunter, a Transposon Tool for Identification and Isolation of Cryptic Antibiotic Resistance Genes." Antimicrobial Agents and Chemotherapy 47, no. 12 (2003): 3840–45. http://dx.doi.org/10.1128/aac.47.12.3840-3845.2003.
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ABSTRACT GeneHunter is a transposon tool designed for the experimental activation and identification of silent antibiotic resistance genes. The method permits the identification of novel resistance genes that lack previously identified homologues. Using Salmonella enterica serovar Typhimurium strain LT2 as a test organism for the in vivo version of the GeneHunter method, we were able to activate, clone, and identify two cryptic antibiotic resistance genes, the aminoglycoside acetyltransferase aac(6′)-Iaa and the probable Mar-A regulon activator rma. Because the method requires being able to electroporate the host with an efficiency of at least 1010 transformants per microgram, the in vivo method is not applicable to most microorganisms. We therefore developed an in vitro transposition method, showed that it can also recover the cryptic rma gene from S. enterica serovar Typhimurium strain LT2, and showed that it is generally applicable to a variety of microorganisms by using it to recover a cryptic metallo-β-lactamase gene from the gram-positive organism Bacillus cereus. It is anticipated that the GeneHunter method will be used to identify potential resistance genes during the development and testing of novel antibiotics, new variants of existing antibiotics, and drug inhibitor combinations.
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Pise, Nitin D., and Swapnil B. Kaikade. "Analysis of prescribing pattern of antimicrobial agents and its rationality in tertiary care rural setup of Central India." International Journal of Basic & Clinical Pharmacology 6, no. 9 (2017): 2289. http://dx.doi.org/10.18203/2319-2003.ijbcp20173761.
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Background: Antimicrobial agents are most commonly prescribed drug and share major cost of the treatment. Excessive and inappropriate use of antimicrobial has become a global problem, resulting not only in substantial economic burden on healthcare system but also in contributing to the selective pressure favoring the emergence of antibiotic-resistant microorganisms. Antimicrobial agents which one uses for prophylactic, empiric and therapeutic purposes, depends upon the local epidemiology of infectious diseases, microbiology and resistance pattern as well as local clinical experience. Rational use of antibiotics is one of the most important way of preventing development of resistant strains to these drugs. However, for this, the health care providers should be aware of the available antibiotic prescription guidelines and should strictly adhere to it. Also, they should be updated of emerging resistant strains. Though the strict guidelines are available for the use of antibiotics, there are differences in level of knowledge and approach to antibiotic prescription among professional health care providers.Methods: The present cross sectional study was carried out in A.V.B.R. Teaching Hospital by collecting data from admitted patient’s case paper, tabulated in seven groups of diseases and different groups of antimicrobial agents prescribed.Results: Penicillin and quinolone group of antimicrobials show maximum use whereas sensitivity found more in cephalosporins and quinolone group of antimicrobials.Conclusions: It was found that Cephalosporins (3rd Gen.) are the most commonly prescribed antimicrobial agents followed by aminoglycosides (Gentamicin) and Fluroquinolones (Ciprofloxacin).
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Khodabandeh, Mahmoud, Mohsen Mohammadi, Mohammad Reza Abdolsalehi, et al. "High-Level Aminoglycoside Resistance in Enterococcus Faecalis and Enterococcus Faecium; as a Serious Threat in Hospitals." Infectious Disorders - Drug Targets 20, no. 2 (2020): 223–28. http://dx.doi.org/10.2174/1871526519666181130095954.
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Aims and Objectives: The present work aimed to evaluate the frequency of aminoglycoside- modifying enzymes encoding genes in the E. faecalis and E. faecium and their antibiotic resistance profile. Methods: A total of 305 different clinical samples were subjected for identification and antibiotic susceptibility test. The high-level aminoglycoside resistance was identified by MIC and Kirby Bauer disc diffusion method. The prevalence of aac (6')-Ie-aph (2'')-Ia, aph (3')-IIIa and ant (4')- Ia genes was determined by multiplex- PCR. In total, 100 enterococci strains were isolated. The prevalence of E. faecalis and E. faecium isolates was 78% and 22%, respectively. Results: All isolates were susceptible to linezolid. So, all E. faecalis were susceptible to vancomycin but, 36.4% of E. faecium were resistant to it. The prevalence of multiple drug resistance strains was 100% and 67.9% of E. faecium and E. faecalis, respectively. High-level-gentamicin and streptomycin resistant rates were as follows; 26.9% and 73.1% of E. faecalis and 77.3% and 90.1% of E. faecium. Conclusion: The results of the current study showed a high frequency of aac (6')-Ie-aph (2'')-Ia genes among enterococcal isolates. A high rate of resistance to antimicrobials in Enterococcus is obviously problematic, and a novel policy is needed to decrease resistance in these microorganisms.
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Junior, Adelino Freire, Fernando Fagundes, Mozar Castro Neto, Carine Barbosa, and Thais Alves. "Evaluation of Initial Outcomes of an Antimicrobial Stewardship Program in a Nonprofit Hospital in Brazil." Infection Control & Hospital Epidemiology 41, S1 (2020): s228—s229. http://dx.doi.org/10.1017/ice.2020.775.
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Background: One of the main global public health challenges is the fight against microbial resistance, according to the World Health Organization. Inadequate use of antimicrobials is considered one of the main factors related to the phenomenon and is quite common in the hospital environment. Managing the use of antimicrobials in hospitals has become a necessity and has shown positive results in many ways, such as maximizing the effects of pharmacotherapy, preventing the emergence of resistant microorganisms, and reducing healthcare costs. Methods: The prescriptions for patients admitted to a 380-bed nonprofit private hospital in Belo Horizonte, Brazil were monitored from January 1, 2019, to August 31, 2019, with a monthly average of 251 patients followed by the antimicrobial stewardship (AMS) team (1 infectious diseases doctor and 2 clinical pharmacists). Patients selected for follow-up and intervention were those submitted to intravenous, intramuscular, and/or oral antibiotic therapy with the following antimicrobial agents: piperacillin/tazobactam, carbapenem, polymyxin B, tigecycline, vancomycin, teicoplanin, daptomycin, third- and fourth-generation cephalosporins, quinolone, and aminoglycosides. Patients on prophylactic or antimicrobial treatment not mentioned above were excluded from surveillance. Interventions were dose adjustments, drug adjustment by culture results, intravenous to oral treatment switch, and discontinuation of therapy. Results: There were 318 interventions, and 64.82% of the interventions performed by the AMS team were accepted by prescribers. The interventions provided a total savings of BR$ 119,706 (~US$30,000) in direct antimicrobial spending. Correlating the interventions with the defined daily dose (DDD) measurement and comparing data from the same period in 2018, we detected a reductions in the consumption of several antimicrobials: ceftriaxone (25.6%), ciprofloxacin (45.7%), meropenem (34%), piperacillin/tazobactam (12.7%), teicoplanin (18.8%), vancomycin (20.6%), cefepime (23.9%) and polymyxin B (26%). We also detected reductions in days of therapy (DOT) for most of these drugs, such as polymyxin B, with an average reduction of 2 DOT. Conclusions: Reducing antimicrobial use is one of the key strategies for avoiding unnecessary exposure and selective pressure leading to the emergence of resistant microorganisms. The measured data point to a favorable trend in the rational use of antimicrobials in our institution with simple interventions. The results presented were used to reaffirm the importance of the AMS team in our institution. More data on length of stay, indirect costs, reduction of side effects, mortality, and occurrence of microbial resistance should be made.Funding: NoneDisclosures: None
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Kryukov, E., Shamil' Gizatullin, Daniil Korabelnikov, Marat Ziyatdinov, Anastasia Sidorova, and Ekaterina Kolobaeva. "The main pathogens of healthcare-associated infections in patients of neurosurgery intensive care unit and antimicrobial activity of the most used antibacterial drugs." Russian Medical and Social Journal 1, no. 2 (2019): 40–56. http://dx.doi.org/10.35571/rmsj.2019.2.004.
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Importance. Healthcare-associated infectionsare an important issue in the neurosurgery. The changes in the epidemiological structure of etiological agents, the increase of antimicrobial drug resistance may lead to the ineffectiveness of previously used patterns for the prevention and treatment of healthcare-associated infections.
Objective.The aim of the research was to study the microbiological structure of leading etiological agents that cause healthcare-associated infectionsin patients of neurosurgery intensive care unitand to evaluate the effectiveness of the most used antibacterial drugs.
Patients and Methods.A retrospective statistical analysis of the results of microbiological monitoring of pathogens of healthcare-associated infectionsin patients of neurosurgery intensive care unitin 2013-2017 was carried out.
Results. The share of gram-negative microorganisms among all isolated microorganisms in the period 2013-2017 increased from 42.47% in 2013 to 54.10% and 50.68% in 2016 and 2017.K. pneumoniae, A. baumannii, P. aeruginosa were most often isolated among gram-negative pathogens, and S. aureus, E. faecalis, and S. Epidermidis- amonggram-positive pathogens; the total rate of these six microorganisms progressively increased from 58.91 % in 2013 to 80.51% in 2017. The rateof A. baumanniiincreased from 8.22% in 2013 to 15.58% in 2017 and the rate of K. pneumoniae- from 5.48% in 2013 to 14.29% in 2017, stable significant detectability of P. aeruginosatended to increase (from 9, 59% in 2013 to 11.69% in 2017). Enterococcus spp. was identified at a significantly high level, mainly E. faecalis and E. faeciumwere represented. E. faecalis dominated (10.96% in 2013, 12.35% in 2014, 10.24% in 2015, 8.70% in 2016, 6.49% in 2017) among the isolated Enterococcus spp. A dynamic decrease in the antimicrobial activity of most used antibacterial drugs was revealed. The greatest dynamic decrease in antimicrobial activity was observed in the aminoglycoside antibiotics - gentamicin and amikacin; amoxicillin / clavulanic acid and levofloxacin. The sensitivity to vancomycin and linezolidremained at levels close to 100%.
Conclusions.Today recommendations for perioperative antibiotic prophylaxis with cefazolin remain relevant. When conducting empirical antibacterial therapy, it is justified to use a combination of vancomycin with the IIId generation cephalosporins until the results of a microbiological study are obtained. An increase in the rate of resistant microorganisms complicates antibacterial therapy, requires the usage of several antibacterial drugs and increase the importance of preventive actions.
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Martynenko, H. A. "Analysis and forecasts of Salmonella spp. antibiotic resistance in Dnipropetrovsk region (Ukraine)." Veterinary Medicine: inter-departmental subject scientific collection, no. 105 (August 7, 2019): 16–19. http://dx.doi.org/10.36016/vm-2019-105-3.
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The paper presents data of the research aimed at studying the species composition of major pathogens circulating in the region and the resistance to antibacterial drugs in pathogens of salmonella, one of the most common zoonoses. Within the period 2014–2018 the qualitative composition of microflora from biological and pathological materials from different groups of animals was studied in Dnipropetrovsk region. Own research results and the results of the regional veterinary statistical reporting were analyzed. Within the short period of five years, 237 cultures of Gram-negative bacteria were detected and studied. The dominant agent in the studied region was E. coli (56.7%) from the Enterobacteriaceae family. The second most frequent agent in the pathology was Salmonella spp. (10.5%). In total, 29 cultures of salmonella infection were isolated from six species of animals with a predominance of bird isolates. Thus, for different age groups of poultry the most common were S. Gallinarum-Pullorum (56%) and S. Enteritidis (32%). An antibiotic resistance increase in pathogenic salmonella was observed for β-lactam antibiotics (cefazolin, ceftriaxone), aminoglycosides (gentamicin, streptomycin, kanamycin), as well as for tetracycline and polymyxin. Taking into consideration the high level of resistance against norfloxacin in the region’s dominant pathogens of the Enterobacteriaceae family, we performed a forecast in MS Excel graphically and added a trend line. In the course of work it was proved that the Dnipropetrovsk region is a geographic zone with a stable high (86 ± 3.7%) allocation from different groups of animals of Gram-negative microorganisms. It was found that local dominant pathogens are representatives of the Enterobacteriaceae family (E. coli, Salmonella spp.). This data can be used as surrogate resistance markers. The epizootological patterns of animal salmonellosis are determined. It is shown the possibility of forecasting the distribution of antibiotic resistant strains in MS Excel in graphical form by adding a trend line, using quantitative information on the sensitivity of bacteria. Prospects for further research are the prevention and control of the emergence of resistance to antibiotics in veterinary medicine and agriculture in the region and in the country
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Rudenko, Pavel, Yuriy Vatnikov, Nadezhda Sachivkina, et al. "Search for Promising Strains of Probiotic Microbiota Isolated from Different Biotopes of Healthy Cats for Use in the Control of Surgical Infections." Pathogens 10, no. 6 (2021): 667. http://dx.doi.org/10.3390/pathogens10060667.
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Despite the introduction of modern methods of treatment, the creation of new generations of antibacterial agents, and the constant improvement of aseptic and antiseptic methods, the treatment of purulent–inflammatory processes remains one of the most complex and urgent problems in veterinary practice. The article presents the results of the isolation of indigenous microbiota from various biotopes of healthy cats, as well as the study of their biological marker properties for the selection of the most optimal strains in probiotic medicines for the control of surgical infections. It was demonstrated that isolated cultures of bifidobacteria and lactobacilli, which we isolated, revealed high sensitivity to antibiotics of the β-lactam group (excepting L. acidophilus No. 24, L. plantarum “Victoria” No. 22, L. rhamnosus No. 5, L. rhamnosus No. 20, and L. rhamnosus No. 26, which showed a significant variability in sensitivity to antibacterial drugs of this group, indicating the great potential of these microorganisms) and resistance to aminoglycosides, lincosamides, and fluoroquinolones (with the exception of gatifloxacin, which showed high efficiency in relation to all lactic acid microorganisms). The adhesive properties of the isolated lactobacteria and bifidobacteria were variable, even within the same species. It was found that the B. adolescentis No. 23 strain of the Bifidobacterium genus, as well as the L. plantarum No. 8, L. plantarum “Victoria” No. 22, L. rhamnosus No. 6, L. rhamnosus No. 26, L. acidophilus No. 12, and L. acidophilus No. 24 strains of the Lactobacillus genus had the highest adhesive activity. Thus, when conducting a detailed analysis of the biological marker properties of candidate cultures (determining their sensitivity to antimicrobial agents, studying the adhesive properties, and antagonistic activity in relation to causative agents of surgical infection in cats), it was found that the most promising are L. plantarum “Victoria” No. 22, L. rhamnosus No. 26, and L. acidophilus No. 24.
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Ahmed, Dalia, Laith Yaaqoob, and Sehand Arif. "Biosynthesis of TiO2 nanoparticles using prodigiosin and evaluating its antibacterial activity against biofilm producing MDR- Acinetobacter baumannii." Al-Anbar Journal of Veterinary Sciences 13, no. 2 (2020): 137–51. http://dx.doi.org/10.37940/ajvs.2020.13.2.13.
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A rising number of hospital infections were caused by multi drug resistant A.baumannii. This microorganism has become a big global concern for clinicians. This study aimed to evaluate the antimicrobial activity of biosynthesized TiO2 nanoparticles against biofilm producing multi drug resistant A. baumannii. Bacteria were isolated from burn wounds. The selected isolate was identified using the routine biochemical assays, viteck 2, and confirmed by PCR technique, targeting the 16S rRNA and blaOXA-51 genes. Antimicrobial susceptibility tests were performed using Viteck 2 system and the biofilm production was tested by using microtiter plate method. S marcescens was used for production of the prodigiosin which characterized later by UV-visible spectroscopy and then was used for biosynthesis of titanium dioxide nanoparticles (TiO2) NPs. Atomic force microscopy, X-ray diffractometer and field emission scanning electron microscopy were used for characterization of TiO2 NPs. Antimicrobial activity of TiO2 NPs was examined by well diffusion assay using concentration of 0.4- 0.006 mg/ml. The studied isolate was beta-lactamase producer and showed resistance to aminoglycosides, quinolones, furanes and trimethoprim/ sulphonamide, PCR amplification of 16S rRNA and blaOXA-51 genes was used for detection of A baumannii. The selected isolate was a strong biofilm producer with 5.9 times more than the OD values of the control. Atomic force microscopy images showed that the synthesized TiO2 NPs were in spherical shape with an average diameter of 67.49 nm. The TiO2 NPs inhibited the bacterial growth at concentrations of ≥ 0.1mg/ ml and a maximum zone of inhibition recorded was 22 mm at concentration of 0.4 mg/ ml. Biosynthesis of TiO2 NPs using prodigiosin was showed a promising antibacterial activity against strong biofilm producing MDR- A. baumannii.
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Chmielarczyk, Agnieszka, Monika Pomorska-Wesołowska, Dorota Romaniszyn, and Jadwiga Wójkowska-Mach. "Healthcare-Associated Laboratory-Confirmed Bloodstream Infections—Species Diversity and Resistance Mechanisms, a Four-Year Retrospective Laboratory-Based Study in the South of Poland." International Journal of Environmental Research and Public Health 18, no. 5 (2021): 2785. http://dx.doi.org/10.3390/ijerph18052785.
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Introduction: Regardless of the country, advancements in medical care and infection prevention and control of bloodstream infections (BSIs) are an enormous burden of modern medicine. Objectives: The aim of our study was to describe the epidemiology and drug-resistance of laboratory-confirmed BSI (LC-BSIs) among adult patients of 16 hospitals in the south of Poland. Patients and methods: Data on 4218 LC-BSIs were collected between 2016–2019. The identification of the strains was performed using MALDI-TOF. Resistance mechanisms were investigated according to European Committee on Antimicrobial Susceptibility Testing, EUCAST recommendations. Results: Blood cultures were collected from 8899 patients, and LC-BSIs were confirmed in 47.4%. The prevalence of Gram-positive bacteria was 70.9%, Gram-negative 27.8% and yeast 1.4%. The most frequently isolated genus was Staphylococcus (50% of all LC-BSIs), with a domination of coagulase-negative staphylococci, while Escherichia coli (13.7%) was the most frequent Gram-negative bacterium. Over 4 years, 108 (2.6%) bacteria were isolated only once, including species from the human microbiota as well as environmental and zoonotic microorganisms. The highest methicillin resistant Staphylococcus aureus (MRSA) prevalence was in intensive care units (ICUs) (55.6%) but S. aureus with resistance to macrolides, lincosamides and streptogramins B (MLSB) in surgery was 66.7%. The highest prevalence of E. faecalis with a high-level aminoglycoside resistance (HLAR) mechanism was in ICUs, (84.6%), while E. faecium-HLAR in surgery was 83.3%. All cocci were fully glycopeptide-sensitive. Carbapenem-resistant Gram-negative bacilli were detected only in non-fermentative bacilli group, with prevalence 70% and more. Conclusions: The BSI microbiology in Polish hospitals was similar to those reported in other studies, but the prevalence of MRSA and enterococci-HLAR was higher than expected, as was the prevalence of carbapenem-resistant non-fermentative bacilli. Modern diagnostic techniques, such as MALDI-TOF, guarantee reliable diagnosis.
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Horiuk, Y. V., M. D. Kukhtyn, V. V. Horiuk, and S. P. Kernychnyi. "COMPARISON OF THE EFFECT OF ANTIBIOTICS AND BACTERIOPHAGE PHAGE SAVB14 ON BIOFILMS FORMED BY STAPHYLOCOCCUS AUREUS VARIANT BOVIS." Podilian Bulletin: Agriculture, Engineering, Economics, no. 32 (June 29, 2020): 166–74. http://dx.doi.org/10.37406/2706-9052-2020-1-19.
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During the development of mastitis in cows, the formation of a biofilm pathogen is an effective way to preserve it in the microenvironment of mammary gland. Biofilm infections are difficult to treat with antimicrobials, and bacterial resistance to antibiotics increases to 1000-fold level, compared with what is observed when grown in planktonic conditions. The aim of study – to determine and compare the effect of antimicrobial drugs and bacteriophage Phage SAvB14 in the destruction of biofilms formed by S. aureus var. bovis. Isolation and species identification of staphylococci were performed according to conventional methods using BD Baird-Parker Agar medium (HiMedia, India). Determination of ability of staphylococci to form biofilms and the number of viable bacteria was determined by the Stepanovic method. The study of sensitivity of microorganisms in biofilm form was performed on daily microbial biofilms grown in plastic Petri dishes. After 24 hours of incubation of cultures, the dishes were washed three times from planktonic (unattached) microorganisms with sterile phosphate buffer and introduced the studied antibacterial agents. After exposure, the dishes were washed three times with sterile phosphate buffer, introduced 5 cm3 of sterile 0.9% sodium chloride solution and washed the biofilm, took 1.0 cm3 of suspension, prepared a series of ten-fold dilutions, inoculated 1.0 cm3 of each dilution in Petri dishes, poured MPA and incubated at temperature of 370C for 24–48 hours to determine the number of bacteria. In determining the effect of antibiotics on bacterial biofilms, it was found that of the studied antibiotics, enrofloxacin worked best probably due to its low molecular weight and ability to penetrate the pores and channels of the biofilm to microbial cells. After the action of enrofloxacin on biofilms, staphylococcal bacteria were completely inactivated. Also, the antibiotics ceftriaxone and doxycycline were effective against bacteria in biofilms. After the action of ceftriaxone, the number of surviving bacteria was lg 1.9 ± 1.1 CFU/cm2 of biofilm area, and doxycycline lg 2.5 ± 1.2 CFU/cm2. At the same time, under the action of antibiotics penicillins, aminoglycosides and macrolides, the number of surviving microbial cells was about lg 5.3 CFU/cm2 of biofilm area. In studies on the effect of bacteriophage Phage SAvB14 on biofilms formed by S. aureus var. bovis, there was their degradation. At this, viable microbial cells from the biofilm were not isolated. In this case, we can say that the phages penetrated and reached the staphylococcal cells throughout the thickness of biofilm and bacteria were susceptible to this phage. That is, there was a passive treatment of biofilm with phages, in which lysis depended on the rate of virus uptake. Therefore, the obtained results of laboratory studies indicate the prospects of effective use of our selected specific staphylococcal bacteriophage Phage SAvB14 for the destruction of biofilm formed by S. aureus var. bovis – in mastitis of cows.
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Giedraitienė, Agnė, Astra Vitkauskienė, Rima Naginienė, and Alvydas Pavilonis. "Antibiotic Resistance Mechanisms of Clinically Important Bacteria." Medicina 47, no. 3 (2011): 19. http://dx.doi.org/10.3390/medicina47030019.
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Bacterial resistance to antimicrobial drugs is an increasing health and economic problem. Bacteria may be innate resistant or acquire resistance to one or few classes of antimicrobial agents. Acquired resistance arises from: (i) mutations in cell genes (chromosomal mutation) leading to cross-resistance, (ii) gene transfer from one microorganism to other by plasmids (conjugation or transformation), transposons (conjugation), integrons and bacteriophages (transduction). After a bacterium gains resistance genes to protect itself from various antimicrobial agents, bacteria can use several biochemical types of resistance mechanisms: antibiotic inactivation (interference with cell wall synthesis, e.g., β-lactams and glycopeptide), target modification (inhibition of protein synthesis, e.g., macrolides and tetracyclines; interference with nucleic acid synthesis, e.g., fluoroquinolones and rifampin), altered permeability (changes in outer membrane, e.g., aminoglycosides; new membrane transporters, e.g., chloramphenicol), and “bypass” metabolic pathway (inhibition of metabolic pathway, e.g., trimethoprim-sulfamethoxazole).
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Golub, N. B. "RESISTANCE TO ANTIBIOTICS AND THEIR UTILIZATION BY MICROORGANISMS." Biotechnologia Acta 14, no. 3 (2021): 22–29. http://dx.doi.org/10.15407/biotech14.03.021.
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With the development of antibiotics application, their spread in the natural environment increases dramatically. The presence of antibiotics in the environment changes microorganism and other living beings ratio and composition, which causes a negative impact on biochemical processes that take place in the environment. The spread of antibiotic resistance genes in environmental microorganisms is a growing problem of environmental safety and human health. Aim. The objective of the work was to analyze the adaptation mechanisms of microorganisms to the influence of antibiotics and methods for antibiotics utilization. Results. The mechanisms of microorganisms’ adaptation to antibiotics are shown. The conditions for utilization of different antibiotics classes by microorganisms are provided. Conclusions. Methods of antibiotics destruction depend on its structure and physicochemical properties. Physico-chemical methods are used for local waste purification and are not suitable for antibiotics disposal in the natural environment. The decomposition products can also have a negative effect on the microorganisms’ cells. Depending on the class of antibiotics, their biodegradation occurs by different types of microorganisms. It has been shown that sulfonamides and amphinecoles are easily destroyed by many heterotrophic bacteria; biodegradation of aminoglycosides occurs by a strain of Pseudomonas spp.; tetracyclines - mushrooms; β-lactams - through the microorganisms’ association including: Burkholderiales, Pseudomonadales, Enterobacteriales, Actinomycetales, Rhizobiales, Sphingobacteriales. A consortium of destructors must be created to dispose of a specific classes of antibiotics.
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Stillwell, Paul C., Gregory L. Kearns, and Richard F. Jacobs. "Endotracheal Tobramycin in Gram-Negative Pneumonitis." Drug Intelligence & Clinical Pharmacy 22, no. 7-8 (1988): 577–81. http://dx.doi.org/10.1177/106002808802200713.
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This report describes the treatment of resistant gram-negative pneumonitis in a compromised host by the combined use of intravenous and endotracheal tobramycin. The endotracheal administration appeared to have an effect on the serum concentration and elimination rate, necessitating a reduction in the amount of drug given intravenously. The only apparent clinical complication of endotracheal drug administration was transient coughing. The addition of endotracheal aminoglycosides to intravenous antibiotics may be useful in pediatric patients with unresponsive (or other difficult-to-treat) pneumonitis caused by resistant microorganisms. The potential contribution of endotracheal aminoglycosides to the serum level and/or disposition profile must be recognized, and therapeutic drug monitoring guided accordingly when this route of administration is used.
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Zembower, Teresa R., Gary A. Noskin, Michael J. Postelnick, Chieu Nguyen, and Lance R. Peterson. "The utility of aminoglycosides in an era of emerging drug resistance." International Journal of Antimicrobial Agents 10, no. 2 (1998): 95–105. http://dx.doi.org/10.1016/s0924-8579(98)00033-8.
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Avner, Benjamin S., Arsenio M. Fialho, and Ananda M. Chakrabarty. "Overcoming drug resistance in multi-drug resistant cancers and microorganisms." Bioengineered 3, no. 5 (2012): 262–70. http://dx.doi.org/10.4161/bioe.21130.
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Reeves, Analise Z., Patricia J. Campbell, Razvan Sultana, et al. "Aminoglycoside Cross-Resistance in Mycobacterium tuberculosis Due to Mutations in the 5′ Untranslated Region ofwhiB7." Antimicrobial Agents and Chemotherapy 57, no. 4 (2013): 1857–65. http://dx.doi.org/10.1128/aac.02191-12.
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ABSTRACTSince the discovery of streptomycin's bactericidal activity againstMycobacterium tuberculosis, aminoglycosides have been utilized to treat tuberculosis (TB). Today, the aminoglycosides kanamycin and amikacin are used to treat multidrug-resistant (MDR) TB, and resistance to any of the second-line injectable antibiotics, including kanamycin, amikacin, or capreomycin, is a defining characteristic of extensively drug-resistant (XDR) TB. Resistance to kanamycin and streptomycin is thought to be due to the acquisition of unlinked chromosomal mutations. However, we identified eight independent mutations in the 5′ untranslated region of the transcriptional activatorwhiB7that confer low-level resistance to both aminoglycosides. The mutations lead to 23- to 145-fold increases inwhiB7transcripts and subsequent increased expression of botheis(Rv2416c) andtap(Rv1258c). Increased expression ofeisconfers kanamycin resistance in these mutants, while increased expression oftap, which encodes an efflux pump, is a previously uncharacterized mechanism of low-level streptomycin resistance. Additionally, high-level resistance to streptomycin arose at a much higher frequency inwhiB7mutants than in a wild-type (WT) strain. AlthoughwhiB7is typically associated with intrinsic antibiotic resistance inM. tuberculosis, these data suggest that mutations in an uncharacterized regulatory region ofwhiB7contribute to cross-resistance against clinically used second-line antibiotics. As drug resistance continues to develop and spread, understanding the mechanisms and molecular basis of antibiotic resistance is critical for the development of rapid molecular tests to diagnose drug-resistant TB strains and ultimately for designing regimens to treat drug-resistant cases of TB.
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McCollister, Bruce D., Matthew Hoffman, Maroof Husain, and Andrés Vázquez-Torres. "Nitric Oxide Protects Bacteria from Aminoglycosides by Blocking the Energy-Dependent Phases of Drug Uptake." Antimicrobial Agents and Chemotherapy 55, no. 5 (2011): 2189–96. http://dx.doi.org/10.1128/aac.01203-10.
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ABSTRACTOur investigations have identified a mechanism by which exogenous production of nitric oxide (NO) induces resistance of Gram-positive and -negative bacteria to aminoglycosides. An NO donor was found to protectSalmonellaspp. against structurally diverse classes of aminoglycosides of the 4,6-disubstituted 2-deoxystreptamine group. Likewise, NO generated enzymatically by inducible NO synthase of gamma interferon-primed macrophages protected intracellularSalmonellaagainst the cytotoxicity of gentamicin. NO levels that elicited protection against aminoglycosides repressedSalmonellarespiratory activity. NO nitrosylated terminal quinol cytochrome oxidases, without exerting long-lasting inhibition of NADH dehydrogenases of the electron transport chain. The NO-mediated repression of respiratory activity blocked both energy-dependent phases I and II of aminoglycoside uptake but not the initial electrostatic interaction of the drug with the bacterial cell envelope. As seen inSalmonella, the NO-dependent inhibition of the electron transport chain also afforded aminoglycoside resistance to the clinically important pathogensPseudomonas aeruginosaandStaphylococcus aureus. Together, these findings provide evidence for a model in which repression of aerobic respiration by NO fluxes associated with host inflammatory responses can reduce drug uptake, thus promoting resistance to several members of the aminoglycoside family in phylogenetically diverse bacteria.
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Morić, Ivana, Miloje Savić, Tatjana Ilić-Tomić, Sandra Vojnović, Sanja Bajkić, and Branka Vasiljević. "rRNA Methyltransferases and their Role in Resistance to Antibiotics." Journal of Medical Biochemistry 29, no. 3 (2010): 165–74. http://dx.doi.org/10.2478/v10011-010-0030-y.
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rRNA Methyltransferases and their Role in Resistance to AntibioticsMethyltransferases (MTases), a large protein superfamily, commonly use S-adenosyl-L-methionine (SAM) as the methyl group donor. SAM-dependant MTases methylate both nucleic acids (DNA, RNA) and proteins, and thus modulate their activity, function and folding. Methylation of G1405 or A1408 nucleotides of 16S rRNA in aminoglycoside-producing microorganisms confers the resistance to their own toxic product(s). This mechanism of resistance has been considered as unique to antibiotics producers until recently. Since 2003, methylation of 16S rRNA as a mechanism of resistance is increasingly emerging in pathogenic bacteria. This represents a major threat towards the usefulness of aminoglycosides in the clinical practice. A potential solution to the problem involves the design of novel compounds that would act against new ribosomal targets. The second approach to the issue includes the development of resistance MTases' inhibitors, with the idea to prevent them from modifying the bacterial rRNA, and thus reinstate the therapeutic power of existing aminoglycosides. As the latter approach has considerable potential, it is obvious that fundamental research related to protein expression, in-depth understanding of the mechanism of action and resolving a tertiary structure of 16S rRNAs MTases are prerequisites for application in medicine.
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Demirev, Plamen A., Nathan S. Hagan, Miquel D. Antoine, Jeffrey S. Lin, and Andrew B. Feldman. "Establishing Drug Resistance in Microorganisms by Mass Spectrometry." Journal of The American Society for Mass Spectrometry 24, no. 8 (2013): 1194–201. http://dx.doi.org/10.1007/s13361-013-0609-x.
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ჩიკვილაძე დ., Chikviladze D., Gachechiladze Kh გაჩეჩილაძე ხ., Mikeladze M. მიქელაძე მ., and მეტრეველი დ. Metreveli D. "PROFILE OF COLIFORM STRAINS’ ANTIBIOTIC RESISTANCE." TSMU COLLECTION OF SCIENTIFIC WORKS 49 (November 4, 2019): 135–57. http://dx.doi.org/10.52340/csw.v49i0.208.
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The spectrum of sensitivity of 112 E. coli strains isolated from patients with acute intestinal infection to 23 antibiotics was investigated by the agar dilution method, which revealed an increase in drug resistance and the emergence of multidrug-resistant strains (33.04%). It was found that the drug resistance of the pathogen to nalidixic acid and carbopenems increased and its high sensitivity to some ftuoroquinolones, III and IV generation aminoglycosides, penicillins and cephalosporins preserved. The drug resistance in future may lead to the formation of hospital strains among E. coli and alter an epidemiological process and the clinical course of the disease.
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Akshay, Subramanian, Mihai Bertea, Sven N. Hobbie, et al. "Phylogenetic Sequence Variations in Bacterial rRNA Affect Species-Specific Susceptibility to Drugs Targeting Protein Synthesis." Antimicrobial Agents and Chemotherapy 55, no. 9 (2011): 4096–102. http://dx.doi.org/10.1128/aac.01398-10.
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ABSTRACTAntibiotics targeting the bacterial ribosome typically bind to highly conserved rRNA regions with only minor phylogenetic sequence variations. It is unclear whether these sequence variations affect antibiotic susceptibility or resistance development. To address this question, we have investigated the drug binding pockets of aminoglycosides and macrolides/ketolides. The binding site of aminoglycosides is located within helix 44 of the 16S rRNA (A site); macrolides/ketolides bind to domain V of the 23S rRNA (peptidyltransferase center). We have used mutagenesis of rRNA sequences inMycobacterium smegmatisribosomes to reconstruct the different bacterial drug binding sites and to study the effects of rRNA sequence variations on drug activity. Our results provide a rationale for differences in species-specific drug susceptibility patterns and species-specific resistance phenotypes associated with mutational alterations in the drug binding pocket.
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Xiong, Y. Q., J. Caillon, H. Drugeon, G. Potel, and D. Baron. "Influence of pH on adaptive resistance of Pseudomonas aeruginosa to aminoglycosides and their postantibiotic effects." Antimicrobial Agents and Chemotherapy 40, no. 1 (1996): 35–39. http://dx.doi.org/10.1128/aac.40.1.35.
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Adaptive resistance to aminoglycosides in Pseudomonas aeruginosa and other gram-negative bacilli is usually induced by the initial exposure to the drug. We investigated the influence of pH on the adaptive resistance of a clinical P. aeruginosa strain to aminoglycosides in vitro and on their postantibiotic effects. For adaptive resistance, the first-exposure concentrations of both amikacin and netilmicin were one, two, four, and eight times the MIC of each drug and the second-exposure concentrations were two times the MIC of each drug. Adaptive resistance was greater and more prolonged with higher initial aminoglycoside concentrations, and the bactericidal effects of the aminoglycosides were concentration dependent at pH 7.4. At pH 6.5, the killing rates of amikacin and netilmicin were far lower than those observed at pH 7.4. At pH 5.5, amikacin and netilmicin exerted practically no bactericidal effect on the P. aeruginosa strain used. However, with media at pH 5.5 and 6.5, adaptive resistance of P. aeruginosa preexposed to amikacin and netilmicin was also clearly exhibited, with the degree of adaptive resistance depending on the bactericidal effects of both drugs on nonpreexposed controls. Maximal adaptive resistance occurred between 0 and 4 h after preexposure. The postantibiotic effects of amikacin and netilmicin against the P. aeruginosa strain were shown to be concentration dependent and were reduced at acidic pHs. No changes in outer and inner membrane proteins occurred during the adaptive-resistance interval.
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Coutinho, Henrique D. M., José G. M. Costa, Edeltrudes O. Lima, Vivyanne S. Falcão-Silva, and José P. Siqueira-Júnior. "In vitrointerference ofMomordica charantiain the resistance to aminoglycosides." Pharmaceutical Biology 00, no. 00 (2009): 090818050145039–4. http://dx.doi.org/10.1080/13880200902991540.
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Reena Rajan. "Mechanism of Drug Resistance in Enterococci and Therapeutic Options - A Review." International Journal of Research in Pharmaceutical Sciences 12, no. 1 (2021): 102–6. http://dx.doi.org/10.26452/ijrps.v12i1.3942.
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Enterococci exhibit an array of ways for constitutional and extrinsic resistance to primary antimicrobial agents available for clinical use. Susceptibility of these agents to β lactams, aminoglycosides or glycopeptides antibiotics or low susceptibility to combination of these agents, monomicrobial or polymicrobial nature of the infection, the involvement of heart valves or other endovascular structures affects therapy of Enterococcal infection. Vancomycin-resistant phenotypes A and B are most prevalent among medically important Enterococci isolates. Due to poor uptake of aminoglycosides, moderate level inherent resistance was reported in Enterococci. Gentamicin and Streptomycin are among the aminoglycoside antibiotics recommended for synergistic combination therapy with a cell wall acting agent. Enterococci isolates display inherent resistance to beta-lactam antibiotics due to less affinity penicillin-binding proteins, class B. Resistance to macrolides, due to erm B genotype and efflux proteins are common in Enterococci. Fluoroquinolone resistance due to genetic changes in chromosomal resistance determining regions has been observed in Enterococci isolates. Despite studies on good invitro action of Daptomycin, Linezolid and Tigecycline on Enterococci, their use may be limited due to shortage of clinical data and emergence of drug resistance. Thus optimal therapeutic option for Multidrug-resistant Enterococci infection is based on empirical observation, higher doses and combination therapies. This article reviews the antimicrobial resistance mechanism in Enterococci and available therapeutic options.
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Dhamdhere, Girija, Ganesh Krishnamoorthy, and Helen I. Zgurskaya. "Interplay between Drug Efflux and Antioxidants in Escherichia coli Resistance to Antibiotics." Antimicrobial Agents and Chemotherapy 54, no. 12 (2010): 5366–68. http://dx.doi.org/10.1128/aac.00719-10.
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ABSTRACT We investigated possible cross talk between endogenous antioxidants glutathione, spermidine, and glutathionylspermidine and drug efflux in Escherichia coli. We found that cells lacking either spermidine or glutathione are less susceptible than the wild type to novobiocin and certain aminoglycosides. In contrast, exogenous glutathione protects against both bactericidal and bacteriostatic antibiotics. The glutathione protection does not require the AcrAB efflux pump but fails in cells lacking TolC because exogenous glutathione is toxic to these cells.
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Hocquet, Didier, Christelle Vogne, Farid El Garch, et al. "MexXY-OprM Efflux Pump Is Necessary for Adaptive Resistance of Pseudomonas aeruginosa to Aminoglycosides." Antimicrobial Agents and Chemotherapy 47, no. 4 (2003): 1371–75. http://dx.doi.org/10.1128/aac.47.4.1371-1375.2003.
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ABSTRACT Exposure of Pseudomonas aeruginosa to aminoglycosides frequently selects for recalcitrant subpopulations exhibiting an unstable, “adaptive” resistance to these antibiotics. In this study, we investigated the implication in the phenomenon of MexXY-OprM, an active efflux system known to export aminoglycosides in P. aeruginosa. Immunoblotting experiments demonstrated that the transporter MexY, but not the outer membrane pore OprM, was overproduced during the post-drug exposure adaptation period in wild-type strain PAO1. Furthermore, MexY production was dependent upon the degree of bacterial exposure to gentamicin (drug concentration). In contrast to parental strain PAO1, mutants defective in MexXY or in OprM were unable to develop adaptive resistance. Altogether, these results indicate that the resistance process requires the rapid production of MexXY and the interaction of these proteins with the constitutively produced component OprM.
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Wargo, Kurt A., and Jonathan D. Edwards. "Aminoglycoside-Induced Nephrotoxicity." Journal of Pharmacy Practice 27, no. 6 (2014): 573–77. http://dx.doi.org/10.1177/0897190014546836.
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Aminoglycosides are among the oldest antibiotics available to treat serious infections caused by primarily, Gram-negative bacteria. The most commonly utilized parenteral agents in this class include gentamicin, tobramycin and amikacin. Aminoglycosides are concentration-dependent, bactericidal agents that undergo active transport into the cell where they inhibit protein synthesis on the 30S subunit of the bacterial ribosome. As the use of aminoglycosides became more widespread, the toxic effects of these agents, most notably ototoxicity and nephrotoxicity, became more apparent. When other, safer, antimicrobial agents became available, the use of aminoglycosides sharply declined. The development of multi-drug resistance among bacteria has now lead clinicians to reexamine the role of the aminoglycosides in the treatment of serious infections. This review will revisit the mechanism and risk factors for the development of aminoglycoside-induced nephrotoxicity, as well as strategies to prevent patients from developing nephrotoxicity.
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Jassem, Agatha N., James E. A. Zlosnik, Deborah A. Henry, Robert E. W. Hancock, Robert K. Ernst, and David P. Speert. "In VitroSusceptibility of Burkholderia vietnamiensis to Aminoglycosides." Antimicrobial Agents and Chemotherapy 55, no. 5 (2011): 2256–64. http://dx.doi.org/10.1128/aac.01434-10.
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ABSTRACTBurkholderia cepaciacomplex (BCC) bacteria are opportunistic pathogens that can cause severe disease in cystic fibrosis (CF) patients and other immunocompromised individuals and are typically multidrug resistant. Here we observed that unlike other BCC species, most environmental and clinicalBurkholderia vietnamiensisisolates were intrinsically susceptible to aminoglycosides but not to cationic antimicrobial peptides or polymyxin B. Furthermore, strains acquired aminoglycoside resistance during chronic CF infection, a phenomenon that could be induced under tobramycin or azithromycin pressurein vitro. In comparing susceptible and resistantB. vietnamiensisisolates, no gross differences in lipopolysaccharide structure were observed, all had lipid A-associated 4-amino-4-deoxy-l-arabinose residues, and all were resistant to the permeabilizing effects of aminoglycosides, a measure of drug entry via self-promoted uptake. However, susceptible isolates accumulated 5 to 6 times more gentamicin than a resistant isolate, and aminoglycoside susceptibility increased in the presence of an efflux pump inhibitor.B. vietnamiensisis therefore unusual among BCC bacteria in its susceptibility to aminoglycosides and capacity to acquire resistance. Aminoglycoside resistance appears to be due to decreased cellular accumulation as a result of active efflux.
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Fong, Desiree H., and Albert M. Berghuis. "Structural Basis of APH(3′)-IIIa-Mediated Resistance to N1-Substituted Aminoglycoside Antibiotics." Antimicrobial Agents and Chemotherapy 53, no. 7 (2009): 3049–55. http://dx.doi.org/10.1128/aac.00062-09.
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ABSTRACT Butirosin is unique among the naturally occurring aminoglycosides, having a substituted amino group at position 1 (N1) of the 2-deoxystreptamine ring with an (S)-4-amino-2-hydroxybutyrate (AHB) group. While bacterial resistance to aminoglycosides can be ascribed chiefly to drug inactivation by plasmid-encoded aminoglycoside-modifying enzymes, the presence of an AHB group protects the aminoglycoside from binding to many resistance enzymes, and hence, the antibiotic retains its bactericidal properties. Consequently, several semisynthetic N1-substituted aminoglycosides, such as amikacin, isepamicin, and netilmicin, were developed. Unfortunately, butirosin, amikacin, and isepamicin are not resistant to inactivation by 3′-aminoglycoside O-phosphotransferase type IIIa [APH(3′)-IIIa]. We report here the crystal structure of APH(3′)-IIIa in complex with an ATP analog, AMPPNP [adenosine 5′-(β,γ-imido)triphosphate], and butirosin A to 2.4-Å resolution. The structure shows that butirosin A binds to the enzyme in a manner analogous to other 4,5-disubstituted aminoglycosides, and the flexible antibiotic-binding loop is key to the accommodation of structurally diverse substrates. Based on the crystal structure, we have also constructed a model of APH(3′)-IIIa in complex with amikacin, a commonly used semisynthetic N1-substituted 4,6-disubstituted aminoglycoside. Together, these results suggest a strategy to further derivatize the AHB group in order to generate new aminoglycoside derivatives that can elude inactivation by resistance enzymes while maintaining their ability to bind to the ribosomal A site.
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Khurshid, Mohsin, Muhammad Hidayat Rasool, Muhammad Hussnain Siddique, et al. "Molecular mechanisms of antibiotic co-resistance among carbapenem resistant Acinetobacter baumannii." Journal of Infection in Developing Countries 13, no. 10 (2019): 899–905. http://dx.doi.org/10.3855/jidc.11410.
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Introduction: The spread of carbapenem-resistant Acinetobacter baumannii (CRAB) is difficult to control especially in the hospitals due to the successful mobilization and evolution of the genetic elements harboring the resistant determinants. The study was conducted to examine the distribution of aminoglycosides, tetracycline, and sulfonamide-resistant determinants among CRAB isolates that carry the blaOXA-23 gene.
Methodology: For a total of 160 CRAB strains isolated at tertiary care hospitals of Pakistan that mainly carried blaOXA-23 gene were included in the study to evaluate the assortment of antibiotic resistance genes.
Results: The susceptibility rates of CRAB for other than beta-lactam drugs were 2.5% for both ciprofloxacin and aminoglycosides and 18% and 25% for sulfonamides and tetracyclines, respectively. Polymyxin B (MIC90, 1 g/mL) Colistin (MIC90, 1 g/mL) and Tigecycline (MIC90, 2 g/mL) were most active against these extensively drug-resistant CRAB isolates. The isolates were found to possess various genes mainly the tetB and sul2 for tetracycline and sulfonamide but the genes conferring resistance to aminoglycosides were varied with various combinations.
Conclusion: Despite the CRAB clones containing blaOXA-23 have been previously reported in Pakistani hospitals, the screening of genetic determinants responsible for other antimicrobial agents is crucial for developing an effective surveillance and mitigation system for infection management.
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Noor, Rashed, Syeda Muntaka Maniha, Taskina Murshed, and M. Majibur Rahman. "Effectiveness of Antibiotics: Anti-Bacterial Activity or Microbial Drug Resistance?" Bangladesh Journal of Microbiology 36, no. 2 (2020): 111–14. http://dx.doi.org/10.3329/bjm.v36i2.45537.
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Antibiotics, both broad- and narrow spectrum, are widely used for treatment of specific infection by a consortium of microorganisms or by a single pathogen, respectively. Oral or intravenous, or even topical administration of different categories of antibiotics in various forms is a common practice round the globe. Yet for the recent years a major public health issue has been raised by the emergence of the drug-resistance microorganisms. A number of researches focused on the issue of the ineffectiveness of antibiotics as well as regarding the evolution of the drugresistance genes within the pathogenic microorganisms. Isolation of the drug-resistant microorganisms including the multi-drug resistant (MDR) and the extensively drug resistant (XDR) bacteria from a range of patients with microbiological infections has been seriously challenging the disease mitigation approaches. Besides, the dominance of the methicillin resistant Staphylococcus aureus (MRSA), vancomycin resistant Staphylococcus aureus (VRSA), etc. are quite frequent as evident from different case studies. Current review focused on the origin and evolution of such drug-resistance incidences, and the promising remedies over the problems of drug-resistance.
Bangladesh J Microbiol, Volume 36 Number 2 December 2019, pp 111-114