Antibiotic resistance of Enterococcus species isolated from raw foods of animal origin in South West part of Slovakia

We determined the prevalence and antibiotic resistance of enterococci isolated from raw foods of animal origin (pork, poultry meat, cow milk, ewe milk, ewe cheese). All samples were positive for enterococci. The lowest count of enterococci was found in pork (2.00 log CFU/square cm), while bryndza cheese contained the highest count (4.99 log CFU/g). Among the 349 Enterococcus isolates, 49% were E. faecalis, 29% E. faecium, and 13% Enterococcus spp. Tetracycline and gentamicin resistance were the most common. We found the highest tetracycline resistance levels (91%) in isolates from poultry samples. These isolates also displayed multidrug resistance to all antibiotics tested. The most common vancomycin-resistant species in poultry and milk was E. faecalis. In contrast, pork samples contained vancomycin-resistant E. faecium isolates. It is interesting to note that vancomycin resistance in pork and poultry samples was found only in combination with either four (28%) or all five (14%) of the tested antibiotics. Our results suggest that raw products of animal origin are possible reservoirs of multi-antibiotic resistant enterococci in the food chain.