Methicillin-sensitive and methicillin-resistant Staphylococcus aureus strains and their toxin genes in the nostrils of dogs and workers at an animal shelter

Aims: Methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA, respectively) in the nostrils of dogs and workers at an animal shelter were cultured. Staphylococcal toxin genes were analysed to identify potential health concerns. Methods and Results: Samples were obtained from 441 dogs and 9 workers. The respective isolation rates of S. aureus and MRSA were 49.0% (216/441) and 1.6% (7/441) for shelter dogs and 44.4% (4/9) and 33.3% (3/9) for workers, respectively. Isolation of S. aureus in summer (61.9%) and in adult dogs (59.2%) were significantly higher than those in winter (35.8%) and in juvenile dogs (33.3%) (P < 0.001), respectively. The predominant enterotoxin genotypes and combination profiles of S. aureus were (sea, seb, seg, sei, sem, sen, seo, seu) and (sea, sea-seb, and seg-sei-sem-sen-seo-seu), respectively, and 20% of isolates carried food poisoning-associated enterotoxins. The se profiles in shelter dogs were different from those in general pet dogs and their owners. MRSA isolates were identified as SCCmec IV and VII, and they shared se combination profiles of (sec-seg-sei-sel-sem-sen-seo-seu) and (seb-sek-seq). MRSA in this shelter had similar microbiological characteristics as those reported in CA-MRSA ST59 in humans. Conclusions: Human health-associated bacteria and food poisoning-related toxin genes were identified. Further evaluations of health concerns in animal shelters are necessary. Significance and Impact of the Study: This is the first study to focus on se prevalence and MRSA characteristics in an animal shelter in Taiwan. The MRSA characteristics determined in this study were similar to those of CA-MRSA strains isolated from communities in the past, indicating potential health risks in cities.