Color enhanced scanning electron micrograph (SEM) depicting numerous clumps of methicillin-resistant Staphylococcus aureus (MRSA) bacteria. 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, e.g., virulence factors like toxins, which 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. MSRA infections (bloodstream, pneumonia, bone infections) occur most frequently among people with a weakened immune system in hospitals, healthcare facilities, nursing homes, and dialysis centers. The manifestation of MRSA infections acquired by otherwise healthy individuals first began to emerged in the mid- to late-1990's. These infections in the community are usually manifested as minor skin infections such as pimples and boils. Transmission of MRSA has been reported most frequently in certain populations, e.g., children, sports participants, or jail inmates. Magnification: 9560x.