Prevalence and antibiotic resistance profiles of Enterococcus species in chicken at slaughter level; absence of vanA and vanB genes in E. faecalis and E. faecium

The prevalence of enterococci in neck skin samples of poultry from Ankara region in Turkey was investigated and their antibiotic resistance patterns were determined. In the study, 83 of 106 analyzed neck skin samples were positive for Enterococcus, with E. faecium as the most prevalent species (48%) followed by E. durans (23%) and E. faecalis (19%). Lower numbers were detected for E. gallinarum, E. hirae, E. mundtii and E. casseliflavus. Using the disc diffusion method, it was established that over 90% of E. faecium and E. faecalis isolates were high-level resistant against erythromycin and tetracycline. Four E. faecium isolates were additionally resistant to chloramphenicol, gentamicin and streptomycin, though they were susceptible to penicillin G. The most frequently observed multiple resistance in E. faecium (25%) was against erythromycin, tetracycline, chloramphenicol and streptomycin. Of the E. faecalis isolates, 44% were multiple resistant to erythromycin, tetracycline and streptomycin. Vancomycin resistance could not be demonstrated phenotypically and vanA or vanB genes were not detected by multiplex PCR in any of the isolates. Nevertheless, the observed resistance patterns are of concern for public health.