This 2005 colorized scanning electron micrograph (SEM) depicted numerous clumps of methicillin-resistant Staphylococcus aureus
bacteria, commonly referred to by the acronym, MRSA; Magnified 4780. Recently recognized outbreaks, or clusters of MRSA in community settings have been associated with strains that have some unique microbiologic and genetic properties, compared with the traditional hospital-based MRSA strains, which suggests some biologic properties, e.g., virulence factors like toxins, may allow the community strains to spread more easily, or cause more skin disease. A common strain named USA300-0114 has caused many such of outbreaks in the United States. See PHIL 7820 for a black and white version of this image.