Gram positive cocci in clusters, coagulase positive
Staphylococcus aureus is a ubiquitous organism that colonizes the skin/nares and can cause invasive disease.
MRSA risk factors include:
Health care exposure
Intravenous drug abuse
Purulent skin and soft tissue infection
Infection of prosthetic devices
MSSA - Standard precautions.
MRSA - Requires contact precautions.