Epidemiologia molecular e aspectos da formação de biofilme de Staphylococcus pseudintermedius: uma espécie de importância na medicina veterinária

Abstract

Staphylococcus pseudintermedius is a component of the skin microbiota in healthy dogs. Despite this, it causes a variety of opportunistic infections such as pyoderma, otitis, and urinary tract infections. Some studies report S. pseudintermedius infections in humans, and contact between animals and their owners can facilitate zoonotic transmission. In recent years, a concerning factor has been the increasing antimicrobial resistance. Methicillin-resistant Staphylococcus pseudintermedius (MRSP) strains often exhibit resistance to other antimicrobials, making them multidrug-resistant (MDR) strains. Previous studies have shown a significant clonal diversity among S. pseudintermedius, with over 2000 reported sequence types (STs). The most successful lineages reported are ST71, ST68, and ST45. S. pseudintermedius has the potential to harbor a wide variety of virulence factors, including protein A, cytotoxins, enterotoxins, toxins, and surface proteins, among others. Biofilm formation is another important virulence factor in Staphylococcus species, but it has been little reported in S. pseudintermedius. Therefore, this study aims to evaluate the composition of S. pseudintermedius biofilm and the presence of virulence and resistance factors in the species population. The samples used are from a collection of cultures from Gram-positive cocci Laboratory at UFF (Niterói). The samples were previously identified, and their resistance profile and biofilm formation capacity were studied. The biofilm composition was evaluated through a quantitative assay in microtiter plates. The presence of ica operon and Sps genes was investigated using conventional PCR. A total of 25 samples underwent whole genome sequencing, and their virulence and resistance gene profiles, circulating clone types, Agr and SCCmec types were evaluated. Most strains exhibited polysaccharide biofilm. The complete ica operon (ADBC) was found in 64.9% of strains. All samples presented SpsK, SpsA, and SpsL genes. Other tested genes showed variable distribution. Agr type III was the most prevalent among samples (56.0%). A total of 19 different resistance genes were identified, encoding resistance to a wide range of antimicrobials. Five of these 19 genes (26.3%) were identified in all samples. Six out of 16 sequenced MRSP samples belonged to the worldwide distributed ST71 clone; others belonged to unknown clones (ST2283, ST2285, ST2288, ST2124, ST2287). Most samples had SCCmec type IIIA (6/16 or 37.5%), and three had SCCmec type V (3/15 or 20.0%). Considering the One Health perspective, it is important to monitor animal-origin Staphylococcus species, as their zoonotic potential has been evaluated, and antimicrobial resistance is a growing problem. Little is known about the pathogenicity and carriage of virulence factors in S. pseudintermedius, as well as the characteristics of MDR strains in the region. Studies of this kind are increasingly necessary and relevant. Population dynamics and molecular epidemiology studies of infections caused by multidrug-resistant staphylococci in companion animals are important as they can provide critical data to guide public health programs.