Identifying high risk patients for Staphylococcus aureus infections: skin and soft tissue infections

Staphylococcus aureus is the causative organism for many skin and soft tissue (SST) infections. Some SST infections have severe systemic complications, such as bacteraemia and sepsis. S. aureus is the cause of 75% of primary pyodermas. Pre-existing conditions, like tissue injury (ulcers, wounds) or tissue inflammation (exudative dermatitis), and also underlying disorders (such as poorly controlled insulin-dependent diabetes mellitus or cancer) are some of the risk factors for secondary infection with S. aureus. In S. aureus-infected primary skin disorders (impetigo, recurrent eczema), 2% mupirocin ointment has proved effective in several clinical trials. S. aureus is responsible for 25% of all burn-wound infections, and burn units could be the point of entry and source of spread of methicillin-resistant S. aureus infection outbreaks. Mupirocin (2% ointment) has also proven effective for topical treatment of these infections. Pressure sores develop in 6% of all patients admitted to acute and chronic health care institutions. An average of three aerobic species (including S. aureus) plus one anaerobic species are isolated when infected. Infectious complications are responsible for 60-80% of all intravenous drug user (IVDU) hospital admissions, 5-20% being due to S. aureus infective endocarditis (IE). The origin of IE in IVDUs is probably the skin. Data from a Collaborative Spanish Study of IVDU infectious complications (including more than 10,000 episodes) are discussed.