DETERMINAZIONE DELLE CARATTERISTICHE FENOTIPICHE E GENOTIPICHE DI CEPPI DI STAPHYLOCOCCUS IN RELAZIONE A METICILLINO- E VANCOMICINO-RESISTENZA

OBJECTIVE – The aim of the study was to evaluate the phenotypic and genotypic characteristics of methicillin-resistant Staphylococcus pseudintermedius in samples from dogs and cats processed in the laboratory of a veterinarian teaching hospital. We also performed tests for vancomycinresistance on the same isolates. MATERIALS AND METHODS – A total of 36 strains of Staphylococcus were isolated from 33 dogs and 3 cats (from skin, eyes, ears, urine, surgical wounds and others). The strains were identified by cultivation on selective medium (MSA), by biochemical system (API-Staph®) and by molecular method (HRM-PCR). The evaluation of the resistance pattern of the strains was performed using Kirby-Bauer method, testing different antimicrobial classes in addition to methicillin and vancomycin. We also performed MIC for methicillin and vancomycin. The presence of mecA gene was evaluated by PCR. RESULTS – 31 strain of S. pseudintermedius, 1 strain of S. aureus and 4 strains of other Staphylococcus species were identified by HRM-PCR method. Among the 36 strains of S. pseudintermedius isolated, 19 were phenotypically resistant to methicillin and 16 of these MRSP carried the mecA gene. The 50% of the 36 isolates were found to be multiresistant and 16 of these strains were also methicillin-resistant. No vancomycin-resistant strains were found. CONCLUSIONS – This study confirmed the increasing prevalence of MRSP and the absence so far of vancomycin-resistance in strains of Staphylococcus isolated from small domestic animals. The most reliable methods for the identification of species were the molecular ones, instead of the biochemical, less effective to have conclusive results.