The genetic basis for fluoroquinolone resistance was examined in 30 high-level fluoroquinolone-resistant Escherichia coli clinical isolates from Beijing, China. Each strain also demonstrated resistance to a variety of other antibiotics. PCR sequence analysis of the quinolone resistance-determining region of the topoisomerase genes (gyrA/B, parC) revealed three to five mutations known to be asso...

In this study, we measured the drug resistance conferred by mdfA mutations in two Shigella flexneri strains. A mutant in mdfA genes was constructed by polymerase chain reaction-based, one-step inactivation of chromosomal genes. The antimicrobial susceptibility of parent and mutant strains to fluoroquinolones was determined by minimal inhibitory concentration (MICs). The △mdfA mutants were somew...

The new GenoType Mycobacterium tuberculosis drug resistance second line (MTBDRsl) assay (Hain Lifescience, Nehren, Germany) was tested on 106 clinical isolates and directly on 64 sputum specimens for the ability to detect resistance to fluoroquinolones, injectable drugs (amikacin or capreomycin), and ethambutol in Mycobacterium tuberculosis strains. A total of 63 strains harboring fluoroquinolo...

BACKGROUND Molecular methods for the detection of drug-resistant tuberculosis are potentially more rapid than conventional culture-based drug susceptibility testing, facilitating the commencement of appropriate treatment for patients with drug resistant tuberculosis. We aimed to develop and evaluate high-resolution melting (HRM) assays for the detection of mutations within gyrA, rpsL, and rrs, ...

The distribution of fluoroquinolone resistance-associated point mutations in genes encoding the subunits of DNA gyrase and DNA topoisomerase i.v. was examined in 110 clinical isolates of Staphylococcus aureus. Point mutations were detected by polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis and mutations were further characterized by sequencing of PCR produc...

originated (data not shown), one would perhaps expect to see mutations being lost or gained within the genes potentially affecting quinolone susceptibility. The stability of mutations in genes known to be associated with fluoroquinolone resistance, and the stable MIC values in clonally related MRSA isolates over time, have important implications for quinolone resistance in S. aureus. From this ...

  Target modification and reduced drug accumulation are the main resistance mechanisms against fluoroquinolone antibiotics in Pseudomonas aeruginosa. We performed a genotypic characterization of three major Mex multidrug efflux pumps (MexAB-OprM, MexXY-OprM and MexCD-OprJ) in ciprofloxacin resistant clinical isolates of P. aeru­ginosa, collected from Tehran, Iran this was followed by sequencin...

Streptococcus pneumoniae plays an important role in causing acute exacerbations in patients with chronic respiratory disease. However, few data are available regarding pneumococcal persistence in adult patients with chronic respiratory diseases. Fifty pneumococci recovered from sputum samples (1995 to 2010) from 13 adult patients with ≥ 3 episodes of acute exacerbation or pneumonia, with the sa...

PURPOSE To identify patients who developed acute-onset endophthalmitis after clear corneal cataract surgery, and to compare treatment outcomes between cases caused by fluoroquinolone susceptible organisms versus fluoroquinolone resistant organisms. DESIGN Retrospective case series. METHODS Patients who developed endophthalmitis within six weeks of cataract surgery, and were treated between ...