Staphylococcus chromogenes is a Gram-positive, coagulase-negative member of the bacterial genus Staphylococcus consisting of clustered cocci. The species is associated with mastitis in dairy animals.[1]
S. chromogenes can be a coagulase-variable Staphylococcus sp., with rare but individual populations displaying clotting activity. [2]
Vanderhaeghen. W. Piepers. S. Leroy. F. Van Coillie. E. Haesebrouck. F. De Vliegher. S. Invited review: Effect, persistence, and virulence of coagulase-negative Staphylococcus species associated with ruminant udder health. Journal of Dairy Science. June 18, 2014. 97. 9. 5275–5293. 10.3168/jds.2013-7775. 24952781. free.