Plasmid-Mediated Quinolone Resistance Determinants <i>qnrA</i> , <i>qnrB</i> , and <i>qnrS</i> among Clinical Isolates of <i>Enterobacteriaceae</i> in a Korean Hospital

Abstract

Screening of 368 consecutive nonreplicate clinical isolates of Enterobacteriaceae resistant to nalidixic acid and at least one extended-spectrum beta-lactam revealed the presence of qnrA, qnrB, and qnrS determinants, and identified novel qnrB variants, in Citrobacter freundii isolates. This study also revealed, for the first time, the linkage of qnrB, armA, and extended-spectrum and/or AmpC-type beta-lactamase genes on large conjugative plasmids.