Mikrobiyol Bul
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Letter Multicenter Study
[Results of a multicenter study investigating plasmid mediated colistin resistance genes (mcr-1 and mcr-2) in clinical Enterobacteriaceae ısolates from Turkey].
Colistin is a polymyxin antibiotic which is considered as one of the last line agents against infections due to multidrug resistant or carbapenem resistant gram-negative pathogens. Colistin resistance is associated with chromosomal alterations which can usually cause mutations in genes coding specific two component regulator systems. The first plasmid-mediated colistin resistance gene, mcr-1 was described in Escherichia coli and Klebsiella pneumoniae isolates in December 2015 and followed by another plasmid-mediated colistin resistance gene mcr-2 in 2016. ⋯ However, the presence of mcr-1/mcr-2 genes was not detected among the tested study isolates of Enterobacteriaceae. Although mcr-1/mcr-2 were not detected in our study isolates, it is highly important to understand the mechanism of resistance dissemination and determine the resistant isolates by considering that colistin is a last-line antibiotic against infections of multidrug or carbapenem resistant gram-negative bacteria. Thus, it is suggested that these mechanisms should be followed-up in both clinical and non-clinical (e.g. isolates from food animals, raw meats and environment) isolates of special populations.
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Direct-acting antiviral agents (DAA) such as NS3 protease inhibitors is the first class of drugs used for chronic hepatitis C (CHC) treatment. NS3 inhibitors (PI) with low genetic barrier have been approved to be used in the CHC genotype 1 infections, and in the treatment of compensated liver disease including cirrhosis together with pegile interferon and ribavirin. Consequently, the development of drug resistance during DAA treatment of CHC is a major problem. ⋯ Based on resistance and high resistance mutations, clinically significant mutations were defined in 10/88 (11%) of the patients. Our study shows that it is essential to analyse HCV NS3 protease inhibitors drug resistance before DAA treatment of CHC patients. On the other hand, our results pointed out that analysis of NS5A and NS5B genome region mutations may also be required in the near future.
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Acinetobacter baumannii, an aerobic, non-motile, gram-negative bacterium is an important nosocomial pathogen which shows resistance to the most antibiotics. Carbapenems are the most commonly used antibiotics for the treatment of infections caused by this pathogen. However the emergence of resistance against carbapenems in an increasing rate generates serious problems for antimicrobial therapy. ⋯ The rest two pulsotypes [I (n= 1), J (n= 1)] were in close relation with the main cluster. No common outbreak isolate was detected, but the relationship between the majority of the strains pointed out that there was a cross contamination problem in our hospital. In conclusion blaOXA-51 and blaOXA-23 were detected as predominant genes responsible from carbapenem resistance in our clinical A.baumannii strains, and it was considered that the high prevalence of clones A and B may constitute a threat in terms of hospitalized patients.
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Throughout the history of mankind, tuberculosis (TB) has caused serious illness and still continues to do so. Archaeobiological studies indicated that TB in humans dates back to 4000-8000 BC, and cases were shown to be due to Mycobacterium bovis subsp.bovis rather than Mycobacterium tuberculosis. Moreover, this situation was thought to begin with domestication of animals, consumption of their milk, and living together in the same environment with them. ⋯ The strains isolated from the first and third cases were found to be susceptible to streptomycin (STR), isoniazid (INH), rifampicin (RIF) and ethambutol (EMB), while the strain isolated from the second case was susceptible to STR, INH and RIF, but resistant to EMB. All of the three isolates were resistant to pyrazinamide. As a result, it was concluded that large-scaled and attentive monitoring of TB infections in animals, as well as searching for M.bovis subsp. bovis in TB cases, especially in high-risk groups would be essential for an accurate diagnosis.
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Acinetobacter baumannii strains, are opportunistic pathogens that cause severe nosocomial infections that are difficult to treat due to development of resistance to multiple antibiotics. As the antibiotic choices to be used in treatment are limited, combinations of a variety of antibiotics are used. The aims of this study were to identify the minimal inhibitory concentration (MIC) values of colistin and sulbactam against A.baumannii isolates and to determine the in vitro activity of colistin-sulbactam combination. ⋯ In the assessment of in vitro efficacy of the colistin-sulbactam combination against A.baumannii strains with multidrug resistance, antagonistic effect was observed in all strains. In the resistance and clonal analysis it was determined that the strains belonged to the same clone, and they had the same resistance genes and therefore the result of the in vitro activity was considered to have similar effect among all strains. It was decided that especially in units where critical patients are monitored and where resistant strains that are difficult to treat are isolated, performing synergy studies may be beneficial for the selection of combination treatment and the determination of the treatment combination to be chosen specifically for the hospital or even the unit.