Vancomycin-resistant enterococci isolated from animals and food

One hundred and one chicken products, boiled ham and turkey cold meat were acquired from 18 different supermarkets in Spain during October 1997 to June 1998 and were analyzed for vancomycin-resistant enterococci (VRE). In the same way, 50 intestinal chicken samples from a slaughterhouse were also studied. VRE were detected in 25 of 92 samples of food of chicken origin (27.2%), but no VRE were found in cooked pork or turkey products. VRE were also detected in 8 of 50 intestinal chicken samples from the slaughterhouse (16%). VRE were identified as Enterococcus durans (n=11), Enterococcus faecalis (n=10), Enterococcus faecium (n=10) and Enterococcus hirae (n=2). All these strains were characterized as belonging to the vanA genotype by polymerase chain reaction. Ampicillin, quinupristin/dalfopristin and high level aminoglycoside resistance were frequently found among these strains. Heterogeneity was observed in susceptibility patterns among VRE strains, even in those of the same species. The high rate of colonization of chicken products by vanA containing enterococci detected 6 months to 1 year after the banning of avoparcin as a growth promoter, supports other studies suggesting that the food chain could be a source of VRE colonization in humans and thus a source of VRE infections.