نتایج جستجو برای: gyra and parc mutations
تعداد نتایج: 16853661 فیلتر نتایج به سال:
Fluoroquinolone resistance was characterized in Escherichia coli O78:K80 isolated from diseased turkeys. The level of resistance to fluoroquinolones of the isolates appeared closely correlated with substitutions in GyrA and ParC, but not with the production of the AcrAB efflux pump. Among isolates highly resistant to ciprofloxacin (MIC 8 mg/L) and harbouring identical substitutions (two in GyrA...
INTRODUCTION Due to the emergence of drug-resistant pneumococcal isolates, new fluoroquinolones have been recommended for the treatment of pneumococcal infections. The purpose of this study was to establish surveillance, and to conduct molecular characterization, of fluoroquinolone-resistant Streptococcus pneumoniae in Seville. METHOD Norfloxacin-resistant S. pneumoniae isolates were characte...
OBJECTIVES Ciprofloxacin is the most frequently used member of the fluoroquinolones during initial eradication therapy of Pseudomonas aeruginosa, as well as during acute pulmonary exacerbations. However, its long-term effect on the susceptibility of the commensal flora within the cystic fibrosis (CF) airways has not yet been examined. The aim of this study was therefore to examine the consequen...
Mutants of attenuated Bacillus anthracis with high-level ciprofloxacin resistance were isolated using a three-step in vitro selection. Ciprofloxacin MICs were 0.5 micro g/ml for first-step mutants, which had one of two gyrA quinolone resistance-determining region (QRDR) mutations. Ciprofloxacin MICs were 8 and 16 microg/ml for second-step mutants, which had one of three parC QRDR mutations. Cip...
We have cloned the DNA gyrase and topoisomerase IV genes of Enterococcus faecalis to examine the actions of quinolones against E. faecalis genetically and enzymatically. We first generated levofloxacin-resistant mutants of E. faecalis by stepwise selection with increasing drug concentrations and analyzed the quinolone resistance-determining regions of gyrA and parC from the resistant mutants. I...
Mutation Supply and Relative Fitness Shape the Genotypes of Ciprofloxacin-Resistant Escherichia coli
Ciprofloxacin is an important antibacterial drug targeting Type II topoisomerases, highly active against Gram-negatives including Escherichia coli. The evolution of resistance to ciprofloxacin in E. coli always requires multiple genetic changes, usually including mutations affecting two different drug target genes, gyrA and parC. Resistant mutants selected in vitro or in vivo can have many diff...
Quinolones are a large and widely consumed class of synthetic drugs. Expanded-spectrum quinolones, like ciprofloxacin are highly effective against Gram-negative bacteria, especially Escherichia coli. In E. coli the major target for quinolones is DNA gyrase. This enzyme is composed of two subunits, GyrA and GyrB encoding by gyrA and gyrB, respectively. Mutations in either of these genes cause qu...
In the present study, a multiple-locus variable number tandem repeat analysis (MLVA) was used to assess the molecular epidemiology of Neisseria gonorrhoeae clinical isolates originating from different regions of Russia. MLVA, based on seven loci, was performed on 218 isolates that were previously tested for susceptibility to penicillin, tetracycline and ciprofloxacin and for the presence of cer...
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