[Application of pulsed-field gel electrophoresis (PFGE) to methicillin-resistant strains of Staphylococcus aureus from humans and domestic animals].

BACKGROUND: The aim of the research was to isolate and to identify the methicillin-resistant Staphylococcus aureus (MRSA) strains from cattle and human and to determine their genetic relatedness comparing the DNA restriction patterns. METHODS: Strains of Staphylococcus aureus were isolated from animals (223 strains) and humans (83). The E-test was applied to determine methicillin-resistance. The restriction patterns of DNA were carried out with pulsed field gel electrophoresis (PFGE). RESULTS: Thirty two (14.34%) from animals and 53 (63.8%) from men strains of S. aureus showed resistance to methicillin. PFGE demonstrated that the strains from human and veterinary pathology are different. The microrganisms isolated from men revealed, among them, an high similarity while only two strains, from animals, were considered identical. CONCLUSIONS: The resistance to methicillin involved both human and veterinary pathology. The human MRSA strains were higher than the animals ones. The strains isolated from animals showed a large genomic variability while in man the number of indistinguishable microrganisms, induces to suppose the existence of a prevalent clone. PFGE could be considered the gold standard for molecular characterisation of MRSA isolates.