Vancomycin Resistant Enterococci (VRE) in equine-faecal samples

摘要

The occurrence and prevalence of vancomycin resistant enterococci (VRE) in equine-faecal samples of hospitalized (n=66) and non-hospitalized (n=72) horses were investigated in North West region in England in order to evaluate any potential role of horses to harbour this zoonotic pathogen. Modified culture methods with presumptive selection were used for Enterococcus spp. and VRE. A multiplex polymerase-chain reaction (PCR) method was used for genotyping of VRE. Overall 47 identified VRE isolates (from 264 faecal samples from 138 horses) were collected and only 9 isolates were confirmed and characterized by PCR. The VanC genotype (i.e. vanC-1 gene) was identified in seven isolates and of these, six were from hospitalized horses. One positive isolate of each of VanA and VanD genotype were also detected both in non-hospitalized horses but were untypable by PCR. Furthermore, susceptibility testing by disc diffusion showed that all isolates (n=9) exhibited further resistance to other antibiotics as well as vancomycin (e.g. teicoplanin and streptogramins drugs). Unlike VanA genotype, which is reportedly associated with human infections, PCR revealed that genotypes of most isolates (i.e. VanC genotype) were not common to clinical human isolates. This study suggests that horses are unlikely to have a major role in the zoonotic transmission of VRE in this geographic area. Furthermore, there is an increased apparent prevalence of VRE in hospitalized horses suggesting a possible nosocomial transmission in hospital.