Nontyphoidal Salmonella enterica strains with a nonclassical quinolone resistance phenotype were isolated from patients returning from Thailand or Malaysia to Finland. A total of 10 isolates of seven serovars were studied in detail, all of which had reduced susceptibility (MIC > or = 0.125 microg/ml) to ciprofloxacin but were either susceptible or showed only low-level resistance (MIC < or = 32...

OBJECTIVES The aim of this study was to determine the prevalence and characteristics of qnr-carrying Salmonella isolates from humans in southern Taiwan. METHODS A total of 446 Salmonella isolates collected between 2003 and 2006 were screened for qnrA, qnrB and qnrS by PCR experiments. Genetic structures of qnr were determined by PCR-based methods or direct sequencing of plasmid DNA. RESULTS...

Aeromonas spp. are oxidase positive, gram-negative, facultative anaerobic bacilli that are widely distributed in aquatic environments. A.hydrophila, A.sobria and A.bestiarum may cause severe infections in both human and cold-blooded animals. Environmental persistance of quinolones that are widely used in both human and veterinary medicine plays an important role in the selection of resistant mu...

conclusions ctx-m was the most prevalent esbl genotype in uropathogenic e. coli (upec) isolated from uti. in addition, a high frequency of qnr genes among esbl-producing e. coli was identified in this study. in order to avoid treatment failures, we recommend using phenotypic and molecular methods to diagnose these enzymes and qnr genes. results the highest sensitivity was seen to imipenem (96.7...

Sir, Fluoroquinolones are broad-spectrum antibacterial agents commonly used in clinical practice. When quinolones became widely used, bacterial resistance to them emerged rapidly and, over the past three decades, resistance has continued to increase. In Gram-negative bacteria, quinolone resistance is due primarily to mutations in chromosomal genes encoding quinolone targets DNA gyrase and topoi...

increase in the number of different qnr-positive serotypes was observed in 2007, although the total number of positive isolates was evenly distributed between 2003 and 2007 (Table 1). The qnrS1 variant was highly prevalent in Salmonella Corvallis supporting the results recently published from Denmark, the Netherlands and the UK. 2,6,8 The Danish study included a restricted set of Salmonella Cor...

The objective of this study was to identify mutations in the Quinolone Resistance Determining sources Regions (QRDR) of the gyrA, gyrB, parC, and parE genes and to determine if any of the qnr variants or the aac(6')-Ib-cr variant were present in strains of Salmonella spp. isolated in Brazil. A total of 126 Salmonella spp. strains from epidemic (n = 114) and poultry (n = 12) origin were evaluate...

The increased use of fluoroquinolones has led to increasing resistance to these antimicrobials, with rates of resistance that vary by both organism and geographic region. Resistance to fluoroquinolones typically arises as a result of alterations in the target enzymes (DNA gyrase and topoisomerase IV) and of changes in drug entry and efflux. Mutations are selected first in the more susceptible t...

OBJECTIVES Escherichia coli is regarded as the most important etiological agent of urinary tract infections. Fluoroquinolones are routinely used in the treatment of these infections; however, in recent years, a growing rate of resistance to these drugs has been reported globally. The aims of this study were to detect plasmid-mediated qnrA, qnrB, and qnrS genes among the quinolone-nonsusceptible...

A total of 514 consecutive clinical Escherichia coli isolates, irrespective of resistance background, were collected in the period 2002-2008 in Wenzhou, southern China, to investigate the prevalence of plasmid-mediated quinolone resistance (PMQR). The dominant PMQR gene was aac(6')-Ib-cr, followed by qnr, whereas qepA was absent. A total of 253 (49.2%) of these isolates were aac(6')-Ib-positive...