Combined antimicrobial resistance in Enterococcus faecium isolated from chickens.

Nineteen E. faecium strains isolated from chicken caecum samples, collected in slaughterhouses and highly resistant to vancomycin or gentamicin, were coresistant to erythromycin, and/or tetracyclines, and/or streptogramins, and/or avilamycin. Multiple antibiotic resistance was related to the presence in various combinations of aac(6')-aph(2"), erm(B), emtA, mef(A), tet(L), tet(M), and vanA genes.