No evidence so far for the dissemination of carbapenemase-producing Enterobactericeae in the community in Switzerland

Background: Carbapenemase-producing Enterobacteriaceae represent an increasing threat to public health and to the treatment of serious nosocomial infections. The aim of this study was to screen for the presence of carbapenemase-producing Enterobacteriaceae in human carriers in community settings in Switzerland, a country representative of central Europe. Findings: Three hundred and fourteen stool samples of healthy staff members of a meat-processing company and 291 fecal swabs from primary care patients were recovered in Switzerland between April 2012 and July 2012 and were tested for carbapenemase-producing Enterobacteriaceae isolates by selecting for growth on a carbapenem-containing selective medium. Six resulting isolates (5 Escherichia coli ono 1 Citrobacter youngae) were subjected to antimicrobial susceptibility tests and PCR analysis by screening for the carbapenemase genes bla(OXA-48), bla(VIM), bla(NDM-1), and bla(KPC) as well as for the extended-spectrum beta-lactamase genes bla(TEM), bla(SHV), bla(CTX-M) and bla(CMY-2). No carbapenemase genes were detected. Resistance to beta-lactam antibiotics was due to carriage of the extended spectrum beta-lactamase CTX-M-15 in 4 isolates, to CTX-M-14 in one further isolate and to the plasmidic AmpC beta lactamase CMY-2 in one isolate. Conclusions: These results show that carbapenemase-producing Enterobacteriaceae are as yet not present the community. Continuous surveillance is necessary to anticipate future trends in the prevalence and dissemination of carbapenem resistant isolates in the population.