R. Davies et Ta. Roberts, Antimicrobial susceptibility of enterococci recovered from commercial swine carcasses: effect of feed additives, LETT APPL M, 29(5), 1999, pp. 327-333
Enterococcus faecium is an important nosocomial pathogen often displaying m
ultiple antibiotic resistance. The increase in clinical isolates can be att
ributed in part to hospital practices in antibiotic usage, but there is con
cern that antibiotic-resistant strains might also originate in animals fed
rations containing antibiotic growth promoters. Ingestion of meat from carc
asses contaminated with faecal enterococci might then result in human colon
ization or resistance gene transfer to human enterococci. Because there are
few comparisons of bacteria isolated from matched animals that have, or ha
ve not, been fed a diet containing antibiotic, two such groups of pig carca
sses were sampled at a commercial abattoir. Fort!; isolates from each group
of pigs were tested for their resistance to avilamycin and tylosin. Althou
gh a modest number of pigs was examined, and the number of strains of E. fa
ecium tested was small, there was no evidence that the feeding of a growth
promoter caused selection of enterococci resistant to tylosin or avilamycin
.