Effect of 72-hour transport delay on dog skin infection cultures

Abstract

BACKGROUND: The submission of bacterial cultures to an off-site microbiology laboratory is standard practice in veterinary medicine. The effects of a transport delay on culture results from canine pyoderma samples remain unknown. HYPOTHESIS/OBJECTIVES: The first objective was to evaluate the reliability of Staphylococcus species isolation by aerobic bacterial cultures from samples collected from canine pyoderma when transported to a microbiology laboratory on the collection day. The second objective was to evaluate the effect of a 72-h transport delay on Staphylococcus spp. isolation and antibiotic susceptibilities. ANIMALS: Thirty client-owned dogs with pyoderma that presented to a private dermatology clinic were included in this study. MATERIALS AND METHODS: Three sterile culturettes were used to sequentially swab one pyoderma lesion per dog. Two samples were transported on the collection day (immediate cultures), while one was refrigerated for 72 h before transportation to a microbiology laboratory. Ninety cultures were performed and the results compared. RESULTS: There was good reliability of Staphylococcus spp. isolation between the immediate cultures. There was no significant difference in the Staphylococcus spp. isolation, Staphylococcus spp. methicillin resistance or Staphylococcus pseudintermedius antibiotic susceptibilities with a 72-h transport delay, with the exception of chloramphenicol susceptibilities. CONCLUSIONS AND CLINICAL RELEVANCE: Cultures from canine pyoderma can have good reliability of Staphylococcus spp. isolation when submitted to a microbiology laboratory on the collection day. Cultures that are delayed at 4°C for ≤72 h can still have reliable results regarding S. pseudintermedius isolation and susceptibilities.