Molecular analysis of NDM-1-producing enterobacterial isolates from Geneva, Switzerland
Poirel, Laurent ; Schrenzel, Jacques ; Cherkaoui, Abdessalam ; Bernabeu, Sandrine ; Renzi, Gesuele ; Nordmann, Patrice
In: Journal of Antimicrobial Chemotherapy, 2011, vol. 66, no. 8, p. 1730-1733
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- Objectives To analyse the mechanisms responsible for decreased susceptibility or resistance to carbapenems in several enterobacterial isolates recovered in 2009-10 in Geneva University Hospitals, Switzerland. Methods PCR and sequencing were used to identify β-lactamases, 16S RNA methylases and plasmid-mediated quinolone resistance genes. The transferable properties of the plasmids were analysed, as well as their plasmid type. The strains were typed by multilocus sequence typing. Results Three patients were found to be positive for NDM-1-producing enterobacterial isolates (one with Escherichia coli and Klebsiella pneumoniae, one with K. pneumoniae only and one with Proteus mirabilis), where NDM-1 stands for New Delhi metallo-β-lactamase-1. The blaNDM-1 carbapenemase gene was detected in all isolates in addition to genes encoding narrow-spectrum β-lactamases (TEM-1, SHV-11, OXA-1, OXA-9 and OXA-10), extended-spectrum β-lactamases (CTX-M-15, CMY-16 and CMY-30), ArmA and quinolone resistance determinants (Qnr). The blaNDM-1 gene was located on conjugative IncA/C- or IncF-type plasmids. Upstream of the blaNDM-1 gene, part of ISAba125, previously identified in NDM-1-negative Acinetobacter baumannii, was found. Downstream of the blaNDM-1 gene, variable sequences were found. Conclusions This work constitutes the first identification of NDM-1 producers in Switzerland. Interestingly, patients from whom these NDM-1-producing isolates were recovered had a link with the Indian subcontinent or the Balkans