Glycopeptide resistance in Enterococcus faecium strains from animals and humans

The isolation of vancomycin (glycopeptide)-resistant Enterococcus strains ( GRE) from animals and from foods has led to the assumption that animals cou ld be a reservoir of GRE, mainly Enterococcus faecium, which cause importan t problems in hospitals. The use of the glycopeptide antibiotic avoparcin a s a growth promoter in farm animals is thought to have been responsible for the occurrence of GRE in humans in Europe. Glycopeptide-resistant E. faeci um have been shown to be most prevalent in broiler chickens, the type of an imal in which avoparcin has been used most widely. Some differences in prev alence between countries with different antibiotic-feed policies have been documented, but comparisons are hampered by the different detection methods applied. Vancomycin supplementation of selective enrichment media and plat es as used most frequently in Europe strongly influences isolation results. In the United States, where glycopeptides have not been incorporated in an imal feed, hospital usage is considered to be the sole cause of the relativ ely high prevalence of nosocomial infections caused by GRE. Investigators h ave been looking in many countries for evidence of the transfer of GRE or t he transfer of the genes encoding vancomycin resistance from animals to hum ans. Although resistance genes in E. faecium strains from animals and human s are often similar, the bacteria themselves do not appear to spread readil y between different animal host species and humans. To date, no final concl usions on the possible spread of GRE or glycopeptide resistance genes from animals to humans can be drawn. (C) 1999 Lippincott Williams & Wilkins.