In vitro Oxacillin-Resistant Staphylococcus Sp Strains From Cutaneous Samples of Domestic Dogs and Cats with Skin Diseases in São Paulo, Brazil
World Small Animal Veterinary Association World Congress Proceedings, 2009
C.E. Larsson Junior1; D.A. Henriques2; C.R. Stricagnollo3; T.C. Sales2; C.T.P. Moraes3; M.M. Kogika3; M.H.M.A. Larsson3; L.A. Megale2
1Universidade Anhanguera, São Paulo, Brazil; 2Dognostic Unidade Veterinária Especializada, São Paulo, Brazil; 3Universidade de São Paulo, São Paulo, Brazil

The gram-positive Staphylococcus is a genus that constitutes the normal cutaneous bacterial microbiota of humans and other animal species. However under appropriated conditions the Staphylococcus sp play a role as pathogenic agents of opportunistic infections. Several distinct Staphylococcus has been isolated from dogs and cats, and of particular importance is the Staphylococcus intermedius that can be present in canine healthy and infected skin as well as in systemic canine infections. Initially Penicillin was the antibiotic of choice for the management of staphylococcal infections, however resistant strains has emerged and new semi-synthetic penicillinase-resistant drugs as Oxacillin and Methicillin have been developed and used. During the 80s the first strains of Methicillin-resistant Staphylococcus aureus were isolated. Staphylococcal pathogens originated from canine and feline clinical samples resistant to Methicillin, Fluoroquinolones and other antimicrobial drugs were described in Europe and USA. The present study aimed to identify the occurrence of in vitro Oxacillin (Methicillin)resistant Staphylococcus strains from canine and feline skin samples submitted to a veterinary microbiological laboratory in Sao Paulo, Brazil. A total of 101 Staphylococcus strains were evaluated. After collection the samples were cultured in 5% sheep blood agar, MacConkey agar and mannitol salt agar and subsequently submitted to catalase, coagulase and DNAase tests. The susceptibility test was performed according to Kirby-Bauer method and disc diffusion tests with bactericidal and bacteriostatic drugs were performed including 1 μg Oxacillin disc (Cefar-Sensifar®). Resistence was defined according to the clinical breakpoints described by the Clinical and Laboratory Standards Institute (CLSI). Among the totality of isolates 14.8% (15/101) showed in vitro Oxacillin (Methicillin) resistance. This finding suggest that these strains were also resistant to other available lactam-antibiotics including penicillins, cephalosporins and carbapenems. According to CLSI guidelines 30 μg Cefoxitin discs (Cefar-Sensifar®) were performed in the eight strains identified as S. intermedius. The present study highlights the concern caused by the antibiotic overutilization for veterinarians. To the authors' knowledge, it reports for the first time in Brazil the isolation of S. intermedius and Staphylococcus sp strains showing antibiotic resistance to the majority of available and authorized antibiotic drugs for the treatment of canine and feline skin diseases. Moreover it demonstrates the possible zoonotic role of pets acting as potential reservoirs of multidrug resistant staphylococcal strains to veterinarian personal and animal owners.

Speaker Information
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Carlos Eduardo Larsson, DVM, MSc, PhD
Faculdade de Medicina Veterinária e Zootecnia
Universidade de São Paulo
São Paulo, Brazil

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