Color ehanced Scanning Electron Micrograph (SEM) of Staphylococcus aureus bacteria. Staphylococcus aureus, also known as "golden staph" and Oro staphira, is a facultative anaerobic Gram-positive coccal bacterium. Staph bacteria are one of the most common causes of skin infections in the United States. Most of these skin infections are minor such as pimples and boils, and can be treated without antibiotics, which are also known as antimicrobials or antibacterials. However, staph bacteria also can cause serious infections such as surgical wound infections, bloodstream infections, and pneumonia. Magnification: unknown.