Background and Objectives: Since the fluoroquinolones are the broad-spectrum antibiotics, they affect both Gram-negative and Gram-positive bacteria. These antibiotics are widely prescribed by physicians. As a result, some bacteria, especially Enterobacteriaceae, have shown a resistance to this family of antibiotics. The current study a...

Plasmid-mediated quinolone resistance determinants are emerging among gram-negative pathogens. Here we report results of a retrospective study investigating the prevalence of aac(6')-Ib-cr, qepA, and qnr genes among 19,010 human isolates of non-Typhi Salmonella enterica collected in the United States from 1996 to 2006.

A novel qnr determinant emerged in ciprofloxacin-resistant Vibrio cholerae O1 from the Amazon region of Brazil. This qnrVC1 was in a typical class 1 integron. Its attC showed 89% identity with V. parahaemolyticus superintegron repeats. Analysis showed V. cholerae O1 carrying qnrVC2 associated with a V. cholerae superintegron repeat.

Real-time PCR assays were developed for the enumeration of plasmid-mediated quinolone resistance (PMQR) determinants, such as the qnrA, qnrB, and qnrS genes, in different water samples and chicken feces. The results indicate that the developed assays are specific and sensitive for the quantification of qnr genes in complex samples.

Escherichia coli isolates expressing plasmid-mediated quinolone resistance and expanded-spectrum b-lactamase. Antimicrob Agents Chemother 2006; 50: 1525–7. 9 Strahilevitz J, Engelstein D, Adler A et al. Changes in qnr prevalence and fluoroquinolone resistance in clinical isolates of Klebsiella pneumoniae and Enterobacter spp. collected from 1990 to 2005. Antimicrob Agents Chemother 2007; 51: 30...

We determined the prevalence of plasmid-mediated quinolone resistance mechanisms among non-Typhi Salmonella spp. isolated from humans, food animals, and retail meat in the United States in 2007. Six isolates collected from humans harbored aac(6')Ib-cr or a qnr gene. Most prevalent was qnrS1. No animal or retail meat isolates harbored a plasmid-mediated mechanism.

The gene qnr (qnrA [G. A. Jacoby, K. Walsh, D. Mills, V. Walker, A. Robicsek, H. Oh, and D. C. Hooper, Abstr. 44th Intersci. Conf. Antimicrob. Agents Chemother., abstr. C2-1898a, 2004]; encoding QnrA) was first identified as a transferable quinolone resistance determinant on a multidrug-resistant plasmid in Klebsiella pneumoniae (6, 9) and has been detected in K. pneumoniae, Escherichia coli, E...

OBJECTIVES A burn unit of a hospital in Tunis underwent an endemic situation caused by imipenem-resistant Pseudomonas aeruginosa. For nine non-repetitive isolates of a clonal VIM-2-producing strain, the blaVIM-2 genetic background was characterized and the associated qnrVC1 gene molecularly analysed. METHODS The imipenem resistance mechanism was investigated by phenotypic and molecular tests,...