OBJECTIVES To study the role of Qnr-like pentapeptide repeat proteins (PRPs) from several gram-positive species with quinolone resistance in vitro. METHODS A PCR-based strategy was used to clone and express genes coding for Qnr-like PRPs in Enterococcus faecalis, Enterococcus faecium, Listeria monocytogenes, Clostridium perfringens, C. difficile, Bacillus cereus and B. subtilis in Escherichia...

Recently, low-level quinolone resistance has been associated with DNA acquired from transferable plasmids. Several studies showed a worldwide dissemination of QnrA determinants among enterobacterial isolates (1, 5). However, the presence of the qnr gene in clinical isolates from outpatients has not been hitherto reported for Brazil. The aim of this study was to determine the occurrence of the q...

The widespread presence of plasmid-mediated quinolone resistance determinants, particularly qnr genes, has become a current issue. By protecting DNA-gyrase from quinolones, Qnr proteins confer a low level quinolone resistance that is not sufficient to explain their emergence. Since Qnr proteins were hypothesized to act as DNA-binding protein regulators, qnr genes could have emerged by providing...

BACKGROUND Quinolone resistance in Enterobacteriaceae results mainly from mutations in type II DNA topoisomerase genes and/or changes in the expression of outer membrane and efflux pumps. Several recent studies have indicated that plasmid-mediated resistance mechanisms also play a significant role in fluoroquinolone resistance, and its prevalence is increasing worldwide. In China, the presence ...

1. Jacoby GA, Gacharna N, Black TA et al. Temporal appearance of plasmid-mediated quinolone resistance genes. Antimicrob Agents Chemother 2009; 53: 1665–6. 2. Robicsek A, Jacoby GA, Hooper DC. The worldwide emergence of plasmid-mediated quinolone resistance. Lancet Infect Dis 2006; 6: 629–40. 3. Torpdahl M, Hammerum AM, Zachariasen C et al. Detection of qnr genes in Salmonella isolated from hum...

Increasing quinolone resistance has been reported worldwide, mainly among clinical isolates of Escherichia coli. The objectives of this study were to determine the susceptibility profile, the genetic relatedness, and the prevalence of the qnr gene among ciprofloxacin-resistant Escherichia coli isolated from distinct Brazilian hospitals. A total of 144 ciprofloxacin-resistant Escherichia coli we...

qnrS1, in nontyphoidal salmonellae in the United Kingdom. These data are in contrast to those of recent studies in the United States and France, which show low incidences of qnrS genes in larger strain collections (9,10). The qnr phenotype is in contrast to resistance mediated by mutations in the topoisomerase genes whereby 1 mutation confers low-level resistance to fl uoroquinolones and full r...

PURPOSE Extended spectrum beta-lactamases (ESBLs) are cephalosporinases that confer resistance to a wide variety of oxyimino cephalosporins and create serious therapeutic problems. In addition, the quinolone resistance qnr genes are becoming increasingly prevalent in clinical isolates, some of which also produce ESBL. This study was designed to evaluate the occurrence and genotypic distribution...

We reported previously the characterization of Pax-QNR/Pax-6 products expressed in the avian neuroretina. Five proteins (48, 46, 43, 33, and 32 kDa) were characterized, among which the 33 and 32 kDa proteins are devoid of the paired domain. In contrast to the 48-kDa (containing an alternative paired exon 4a) and 46-kDa proteins exclusively located in the nucleus, the 43- (in which the paired ex...