Staphylococcus aureus accounts for 10% 20% of isolates of brain abscesses in a general population, usually reported in patients with cranial trauma or endocarditis, and it is often isolated in culture. Some cases caused by community-associated methicillin-resistant S. aureus have been reported. Population-based studies have identified male gender and very young and elderly individuals as being at increased risk for S. aureusinfections. Moreover, two studies showed that the most important risk factor is dialysis, either peritoneal (relative risk [RR], 150 to 204) or hemodialysis (RR, 257 to 291). Other conditions that increase the risk of invasive S. aureus infections include diabetes (RR, 7), cancer (RR, 7.1 to 12.9), rheumatoid arthritis (RR, 2.2 to 9.2), HIV infection (RR, 23.7), intravenous drug use (RR, 10.1), or alcohol abuse (RR, 8.2) 1) 2).
However, one of the most important factors that is independently associated to brain abscess is chronic S. aureus nasal carriage 3)