Genetic variability of Staphylococcus Pseudintermedius in animals from Mato Grosso, Brazil: methicillin-resistant clonal complexes and discovery of new sequence types.

Staphylococcus pseudintermedius is one of the main causes of bacterial infection in dogs, and resistant isolates that present zoonotic potential have also been identified. This study aimed to determine the genotypic profiles of Brazilian isolates of S. pseudintermedius from animals, and their population structures. S. pseudintermedius isolates (n = 50) were subjected to methicillin resistance analysis by polymerase chain reaction (PCR) and genotyping by multilocus sequence typing (MLST). The mecA gene, which confers resistance to methicillin, was detected in 84% of the isolates (42/50), and the animal species of origin were 84% dogs, 8% cats, 2% porcine, 2% bovine, and 4% from wild animals. The main isolation sites were skin (38%), ear (26%), and urine (14%). Forty different sequence types (STs) were observed and 39 were described for the first time, including ST226, which, to our knowledge, is reported for the first time in a feline isolate. Three clonal complexes (CC) were present, and CC258 was predominant among the characterized isolates. The variety of STs in the isolates of S. pseudintermedius in this study indicates a high genetic diversity of this species in Brazil. Considering that only one of the observed STs (ST266) has been previously reported, it is likely that the new STs described are clones developed locally. In addition, the predominance and spread of the CC258 clonal complex in Brazil could be associated to resistance to methicillin, demonstrates the establishment of CC258 as a successful clone.