MRSA in Pig Population

Methicillin resistant Staphylococcus aureus (MRSA) is widespread worldwide in different types of animal species and as a zoonosis takes a great risk for human health not only as a food toxicoinfection, but also as a highly resistant pathogen causing serious soft tissue infectious, septicaemia and even death. One of the most affected food-producing animal species is swine in the production of which new antibiotics in big amounts are used more and more continuously, increasing antimicrobial resistance. In this study several commercial pig farms and pigs with different age groups as well as farm workers and samples from environment were examined with the purpose of detecting MRSA prevalence and evaluating antimicrobial resistance. A total of 85 isolated MRSA strains were characterised by conventional microbial and molecular methods. MRSA was found in all farms. MRSA prevalence in different pig age groups and farms varied from none to 79.2% reaching higher values among 3-3.5 (26.6%) and 4-4.5 (31.9%) old pigs. The 98.7% of 74 further investigated MRSA isolates were resistant to penicillin, 94.9% to tetracycline, 45.6% to cephalexin and 10 different spa types were found among which spa type t011 was the most widespread. To the best of our knowledge, this is the first time MRSA was researched in sow milk and the first description of the presence of MRSA in several age groups of pigs in Latvia.