Background: Staphylococcus argenteus is a new specie positive coagulase staphylococci. We investigate the presence of S. argenteus in isolates previously classified as S. aureus, obtained from the milk of cows with mastitis in Brazil.
Results: Among 856 S. aureus tested in chocolate agar, tryptone soya agar and salt egg yolk agar, white or colorless colonies were observed in 185 (21.6%) isolates. Regarding the ctrOPQMN operon, 111 (60%) presented the complete cluster. Despite some missing genes in this cluster, the remaining strains (74) were confirmed as S. aureus using the nrps gene.
Conclusions: As far as we know, this is the first review of S. aureus collection in Brazil and S. argenteus does not appear to be a significant problem in Brazilian herds.
Keywords: S. aureus complex; Salt egg yolk agar; Staphyloxanthin; nrps gene.