Prevalence and in vitro susceptibility of methicillin-resistant Staphylococcus pseudintermedius (MRSP) from skin and nostrils of dogs with superficial pyoderma

In order to assess the prevalence of Methicillin-resistant Staphylococcus pseudintermedius from skin and nostrils of dogs with pyoderma, to determine its in vitro susceptibility, and to correlate these data with the presence of the mecA gene, 43 dogs were selected. Samples were collected from secretion of their skin lesions and right nostril, cultured, and analyzed for phenotypic and genotypic characteristics of the bacteria studied. In 62 samples (91%) the microorganism was classified as S. pseudintermedius. The rate of resistance against antibiotics ranged from 7% (amikacin; 4/62) to 77% (sulfamethoxazole + trimethoprim; 48/62). Resistance against oxacillin was found in 34% of the samples (21/62). Twenty-five samples (37%) were strains that carried the mecA gene. A significant correlation (P0,01) foi observada entre a presença do gene mecA nas lesões de pele e nas narinas. Sendo assim, resistência à oxacilina in vitro pode ser aferida com segurança para indicar a presença do gene mecA em amostras de MRSP, e as narinas podem constituir em um reservatório dos microorganismos em cães.