We examined the potential for the development of fluoroquinolone resistance in Neisseria meningitidis by cultivating two clinical isolates of meningococci in the presence of concentrations of ciprofloxacin at and about the predetermined MIC. The quinolone resistance determining regions (QRDRs) of gyrA and parC of 50 stable quinolone-resistant mutants derived in vitro were sequenced and compared...

The objective of this study was to compare quinolone resistance and gyrA mutations in clinical isolates of Klebsiella pneumoniae and Escherichia coli from Chinese adults who used quinolone in the preceding month and children without any known history of quinolone administration. The antimicrobial susceptibilities of 61 isolates from children and 79 isolates from adults were determined. The muta...

Although resistance to quinolones is commonly chromosomally-encoded in Enterobacteriaceae, the emergence of plasmid-mediated quinolone resistance (PMQR) has also been reported, with at least three known resistance mechanisms to date, i.e., Qnr, aminoglycoside acetyltransferase AAC(6')-Ib-cr and QepA. Qnr proteins protect target enzymes (DNA gyrase and type IV topoisomerase) from quinolone inhib...

BACKGROUND/AIM To detect the effects on quinolone resistance due to biofilm formation activity in Ureaplasma urealyticum. MATERIALS AND METHODS An improved checkerboard dilution susceptibility test was used to analyze the quinolone resistance of clinical Ureaplasma isolates and a postbiofilm formation susceptibility assay was used to compare the effects on the quinolone susceptibility between...

Comprehensive data on the prevalence of quinolone resistance in Mycobacterium tuberculosis clinical isolates in the United States are scarce. By use of a systematic population-based approach, M. tuberculosis strains from tuberculosis (TB) cases were collected in Harris County, TX, in 2007 to 2008. The susceptibilities of M. tuberculosis isolates to moxifloxacin and ofloxacin were determined by ...

INTRODUCTION Typhoid fever is endemic in Egypt; and quinolones are the empirical treatment of choice. There are very limited data reporting quinolone resistance among Egyptian typhoidal Salmonella isolates. We previously reported that all typhoidal Salmonella were sensitive to quinolones. This study aimed to isolate and identify typhoidal Salmonella from cases suffering from enteric fever at Mi...

The amount of sparfloxacin uptake was higher than that of norfloxacin uptake in Staphylococcus aureus. Moreover, energy-dependent reduction in quinolone uptake, probably due to active efflux of the quinolone, was observed. The reduction in quinolone uptake appeared to be associated with quinolone resistance in S. aureus.

OBJECTIVES Pentapeptide repeat proteins (PRPs) QnrA, QnrB and QnrS confer reduced susceptibility to quinolones. This study presents an in vitro analysis of the genetic evolution of quinolone resistance mediated by changes in the coding sequences and promoter regions of qnrA1, qnrS1 and qnrB1 genes. METHODS A random mutagenesis technique was used to predict the evolutionary potential of these ...

Investigation of the Frequency Plasmid-Dependent Quinolone Resistance Genes in Klebsiella Pneumoniae, Pseudomonas Aeruginosa and Escherichia Coli Isolated from Surgical Site Infections

objective(s) extensive use of quinolones has been associated with raising level of resistance. in the current, we focused on assessing the prevalence of escherichia coli resistance to quinolones and frequency of qnra, qnrb and qnrs in non esbls (extended spectrum beta-lactamases) and esbls producing e. coli with blashv and blatem. materials and methods one hundred and fifty e. coli isolates wer...