Changes in <i>qnr</i> Prevalence and Fluoroquinolone Resistance in Clinical Isolates of <i>Klebsiella pneumoniae</i> and <i>Enterobacter</i> spp. Collected from 1990 to 2005

Abstract

Clinical isolates of Klebsiella pneumoniae and Enterobacter spp. collected from 1990 through 2005 at a tertiary care center were studied for qnr genes. Isolates bearing these genes emerged in the mid-1990s, coinciding with the time of a rapid increase in fluoroquinolone resistance. Sixty percent of these isolates were ciprofloxacin susceptible by CLSI breakpoints.