Antimicrobial susceptibility of enterococci strains isolated from slaughter animals on the data of Hungarian resistance monitoring system from 2001 to 2004

Isolates of Enterococcus spp. were collected from January 2001 to December 2004 from caecal samples of slaughtered poultry, swine and cattle in Hungary. The isolates were identified by their growth and biochemical properties and with PCR. The antibiotic susceptibility of a total number of 1272 isolates was tested with disk diffusion test to ampicillin, gentamicin, streptomycin, tetracycline, erythromycin and vancomycin. It was established that although ampicillin and amoxicillin are often used in veterinary practice its resistance rate was relatively low. In the case of tetracyclines and macrolides, a high incidence of resistance was found. Susceptibility of strains to tetracyclines and/or macrolides reduced in both 2003 and 2004 in all animal species, which may be due to the more frequent usage of these drugs in the veterinary practice following the ban of growth promoters. The annual data of vancomycin resistance point to an association between the recovery of vancomycin-resistant enterococci (VRE) isolates and the use of avoparcin. This study indicates that reducing antimicrobial resistance in food animals could be possible with lower usage of antibiotics, although variations can occur with different strains.