S. aureus ST151 and ST3028 on blood agar plates. Both strains were isolated from cases of subclinical mastitis The plates were incubated at 37 C for 24 or 48 hrs as shown in the picture. ST3028 is one of the novel strains recently identified. What is interesting is the differential hemolysis pattern of these two strains. ST3028 look non hemolytic which is unusual in most cow associated strain types. ST3028 is a single locus variant of ST2187 which is a cow adapted S. aureus strain type.
S.aureus hemolysis on blood agar
Image credits: Robert Mugabi