Detection of vancomycin-resistant enterococci from faecal samples of Iberian wolf and Iberian lynx, including Enterococcus faecium strains of CC17 and the new singleton ST573

The aim of this study was to perform the molecular characterization of vancomycin resistant enterococci (VRE) within the faecal flora of Iberian wolf and Iberian lynx. The association with other resistance genes and the detection of virulence genes were also analysed. From 2008 to 2010, 365 faecal samples from Iberian wolf and Iberian lynx were collected and tested for VRE recovery. Mechanisms of resistance to vancomycin and other antibiotics, as well as genes encoding virulence factors were detected through PCR. Multilocus Sequence Typing (MLST) was performed for Enterococcus faecium strains. VRE were recovered in 8 of the 365 analysed samples. The vanA gene was identified in two E. faecium isolates recovered from Iberian wolf faecal samples and the remaining six showed intrinsic resistance (3 vanC1-E. gallinarum and 3 vanC2-E. casseliflavus, from Iberian wolf and Iberian lynx faecal samples, respectively). One vanA-containing isolate showed tetracycline and erythromycin resistance [with erm(B) and tet(L) genes] and the other one also exhibited ampicillin and kanamycin resistance [with erm(B), tet(M) and aph(3')-III genes]. One of the vanA-isolates revealed a new sequence type named ST573 and the other one belonged to the CC17 clonal complex (ST18). The hyl gene was detected in one E. casseliflavus and three E. gallinarum but not among vanA-positive isolates, and the occurrence of cylA and cylL genes was confirmed in two E. casseliflavus isolates. A low prevalence of VRE has been detected in faecal samples of Iberian wolf and Iberian lynx and strains with an acquired mechanism of resistance to vancomycin have not been detected among Iberian lynx.