Emergence of biofilm-producing Staphylococcus pseudintermedius isolated from healthy dogs in South Korea

Background:Staphylococcus pseudintermedius is a common bacterial pathogen in dogs with pyoderma, otitis externa, and wound infection. Objective: The purpose of this study was to evaluate the biofilm-producing ability for methicillin-resistant (MRSP) and methicillin-susceptible (MSSP) S. pseudintermedius isolates from healthy dogs. Animals and methods: Ninety-two isolates, consisting of 40 MRSPs and 52 MSSPs, were included in the study. Biofilm production was determined using a quantitative adherence assay in 96-well tissue culture plates and polymerase chain reaction (PCR) targeting icaA and icaD genes. The prevalence of methicillin-resistance in the isolated S. pseudintermedius was calculated using standard equations. The presence of methicillin resistance (MR) and biofilm-producing ability between nasal- and ocular-origin S. pseudintermedius was compared using the chi-square (χ ² ) test. The associations between the degree of biofilm production and the presence of methicillin-resistance or sample origin were determined using Fisher's exact test. Results: All of the MRSP and MSSP isolates were able to produce biofilms, and 93.5% of the isolates were strong or moderate biofilm producers, regardless of the presence of methicillin-resistance or source. Methicillin-resistance was more prevalent in nasal isolates. There was no association between the presence of icaA/icaD and biofilm production. Conclusions: Findings from this study indicate a high prevalence of biofilm-producing S. pseudintermedius in healthy dogs in South Korea, which may have a significant influence to animal health.