background :    klebsiella pneumoniae is among the most common and significant agents of community and hospital-acquired infections. plasmid mediated quinolone resistance (pmqr) was increasingly identified in enterobacteriaceae family worldwide. plasmid-mediated quinolone resistance (pmqr) was first reported in 1998 from a klebsiella pneumoniae isolate in the usa. till date, five qnr proteins h...

Quinolone antibiotics have been commonly used to treat cases of multiple antibiotic resistance. Unfortunately, quinolone so much resisted by infectious bacterial agents. This study aimed evaluate the susceptibility some clinical isolates E. coli and determination plasmid-encoded resistance genes.
 Our results showed plasmid quinolone-resistance genes in following prevalence: qnr genes: S (...

BACKGROUND The categories of recognized transferable quinolone resistance determinants have been increasing sharply. The rapid horizontal transfer of these quinolone resistance genes has caused concern since they bring new dissemination possibilities for quinolone resistance. METHODS In total, 579 clinical Escherichia coli isolates were subjected to antimicrobial susceptibility testing, scree...

The plasmid-encoded quinolone resistance gene qnrA confers low-level quinolone resistance, facilitating selection of higher-level resistance. Epidemiologic surveys for qnrA were extended to isolates of Enterobacter spp. and to quinolone-susceptible Enterobacteriaceae. Two (10%) of 20 ceftazidime-resistant quinolone-susceptible Klebsiella pneumoniae strains carried the gene, as did 12 (17%) of 7...

background plasmid-mediated quinolone resistance genes (pmqr) have been shown to play not only an important role in quinolone resistance, but also resistance to other antibiotics, particularly β-lactams and aminoglycosides. these genes are mainly associated with clinical isolates of enterobacteriaceae. however, detection of pmqr genes in the community isolates can increase the dissemination rat...

BACKGROUND Antibiotic resistance has necessitated fluoroquinolone use but little is known about the selective forces and resistance trajectory in malaria-endemic settings, where selection from the antimalarial chloroquine for fluoroquinolone-resistant bacteria has been proposed. METHODS Antimicrobial resistance was studied in fecal Escherichia coli isolates in a Nigerian community. Quinolone-...

The mechanism of quinolone-resistance is considered to be amino acid mutations in the type II topoisomerase. We validated the genetic mechanisms of quinolone resistance in Haemophilus influenzae. We obtained 29 H. influenzae strains from a nationwide surveillance program in Japan (including 11 quinolone-resistant strains [moxifloxacin: MFLX or levofloxacin MIC ≥2 μg/ml]). We analyzed the sequen...

Objective(s): Regarding the global burden of uropathogenic Escherichia coli (UPEC) infections, prevention and treatment of such infections play a significant role in healthcare management. The inordinate use of fluoroquinolones led to a worldwide spread of quinolone-resistant strains. Therefore, this study aimed to investigate mutations in codons 83 and 106 of gyrA gene in UPEC isolates in the ...

DNA gyrase is a prokaryotic type II topoisomerase and a major target of quinolone antibacterials. The majority of mutations conferring resistance to quinolones arise within the quinolone resistance-determining region of GyrA close to the active site (Tyr(122)) where DNA is bound and cleaved. However, some quinolone resistance mutations are known to exist in GyrB. Present structural data suggest...