yellow-pigmented colonies; grows in irregular grape-like clusters. Ubiquitous human parasite; present on skin and mucous membranes of 25-50% of human populations. Can be invasive, or highly toxigenic, or both. Produces a wide spectrum of diseases, with much tissue damage. Suppurative wounds (abscesses), and pyogenic wounds (pus). Highest risk is in newborn nursery, intensive care unit, operating room, and cancer chemotherapy wards. Highly opportunistic pathogen.