Resistance to Antibiotics and the Occurrence of Genes Responsible for the Development of Methicillin Resistance in Staphylococcus Bacteria Isolated From the Environment of Horse Riding Centers

The purpose of the study was to identify species, to determine the drug resistance profile, and to evaluate the occurrence of genes responsible for the development of methicillin resistance in Staphylococcus bacteria isolated from the environment of horse riding centers. Staphylococci were isolated from air, manure, and nostrils of horses located in three horse riding centers, differing in horse stabling system-box stall stabling (OJK Pegaz and KJK Szary) and free-range stabling (SKH Nielepice). The dominant species was Staphylococcus vitulinus. A large variation in the frequency of occurrence of individual species between horse riding centers was determined. Resistance to antibiotics was determined by means of disc diffusion method and polymerase chain reaction technique to detect mecA genes responsible for methicillin resistance. In total, 408 strains were collected, most from SKH Nielepice, and least from OJK Pegaz. The highest resistance was found to gentamicin and tetracycline. Multidrug-resistant isolates were also detected in KJK Szary (10), in SKH Nielepice (5), and in OJK Pegaz (4). Methicillin resistance determined by disk diffusion assay was found in 23 strains, while the mecA gene was detected in 142 isolates. A total of 137 strains holding the mecA gene are coagulase-negative staphylococci (CNS), which, as shown by our own studies, may be a reservoir of methicillin resistance. Most commonly, the mecA gene was found in staphylococci isolated in KJK Szary (61.70%). The mecA gene was detected in five strains that belonged to Staphylococcus aureus species and came from horses in SKH Nielepice, indicating the presence of methicillin-resistant Staphylococcus aureus strains in these animals.