I took these combined pictures after growing 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 ST3028 is one of the novel strains recently identified in our lab (unpublished data),http://saureus.mlst.net. 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.