Presence of qnr gene in Escherichia coli and Klebsiella pneumoniae resistant to ciprofloxacin isolated from pediatric patients in China

<p>Abstract</p> <p>Background</p> <p>Quinolone resistance in <it>Enterobacteriaceae </it>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 of the <it>qnr </it>gene in the clinical isolates of <it>Enterobacteriaceae </it>has been reported, but this transmissible quinolone resistance gene has not been detected in strains isolated singly from pediatric patients. Because quinolones associated with a variety of adverse side effects on children, they are not authorized for pediatric use. This study therefore aimed to investigate the presence of the <it>qnr </it>gene in clinical isolates of <it>E. coli </it>and <it>K. pneumoniae </it>from pediatric patients in China.</p> <p>Methods</p> <p>A total 213 of non-repetitive clinical isolates resistant to ciprofloxacin from <it>E. coli </it>and <it>K. pneumoniae </it>were collected from hospitalized patients at five children's hospital in Beijing, Shanghai, Guangzhou, and Chongqing. The isolates were screened for the plasmid-mediated quinolone resistance genes of <it>qnrA</it>, <it>qnrB</it>, and <it>qnrS </it>by PCR. Transferability was examined by conjugation with the sodium azide-resistant <it>E. coli </it>J53. All <it>qnr</it>-positive were analyzed for clonality by enterobacterial repetitive intergenic consensus (ERIC)-PCR.</p> <p>Results</p> <p>The study found that 19 ciprofloxacin-resistant clinical isolates of <it>E. coli </it>and <it>K. pneumoniae </it>were positive for the <it>qnr </it>gene, and most of the <it>qnr </it>positive strains were ESBL producers. Conjugation experiments showed that quinolone resitance could be transferred to recipients. Apart from this, different DNA banding patterns were obtained by ERIC-PCR from positive strains, which means that most of them were not clonally related.</p> <p>Conclusion</p> <p>This report on transferable fluoroquinolone resistance due to the <it>qnr </it>gene among <it>E. coli </it>and <it>K. pneumoniae </it>strains indicated that plasmid-mediated quinolone resistance has emerged in pediatric patients in China.</p

Rapid Evolution and Spread of Carbapenemases among Enterobacteriaceae in Europe

Plasmid-acquired carbapenemases in Enterobacteriaceae, which were first discovered in Europe in the 1990s, are now increasingly being identified at an alarming rate. Although their hydrolysis spectrum may vary, they hydrolyse most β-lactams, including carbapenems. They are mostly of the KPC, VIM, NDM and OXA-48 types. Their prevalence in Europe as reported in 2011 varies significantly from high (Greece and Italy) to low (Nordic countries). The types of carbapenemase vary among countries, partially depending on the cultural/population exchange relationship between the European countries and the possible reservoirs of each carbapenemase. Carbapenemase producers are mainly identified among Klebsiella pneumoniae and Escherichia coli, and still mostly in hospital settings and rarely in the community. Although important nosocomial outbreaks with carbapenemase-producing Enterobacteriaceae have been extensively reported, many new cases are still related to importation from a foreign country. Rapid identification of colonized or infected patients and screening of carriers is possible, and will probably be effective for prevention of a scenario of endemicity, as now reported for extended-spectrum β-lactamase (mainly CTX-M) producers in all European countries. © 2012 European Society of Clinical Microbiology and Infectious Diseases