Staphylococcus aureus colonisation and bacteraemia in persons infected with human immunodeficiency virus: a dynamic interaction with the host.

Bacterial infections are common in persons with symptomatic disease caused by human immunodeficiency virus (HIV). Colonisation and infection with Staphylococcus aureus is present in 30% to 50% of persons with HIV disease. Risk factors for bacteraemia due to S. aureus include nasal colonisation, advanced HIV disease with CD4+ lymphocyte count < 100/mm3, prior hospitalisations, neutropenia, skin lesions, intravenous drug use, and the presence of invasive devices, such as intravenous catheters. Some antibiotics may increase the risk of S. aureus nasal colonisation, and others such as trimethoprim-sulphamethoxazole and rifabutin may reduce colonisation and disease. Preliminary data suggest that mupirocin may decrease nasal colonisation with S. aureus, but the optimal regimen, duration of effect, use, and concerns about resistance, need further evaluation. Recent data suggest that bacterial infection may accelerate the progression of HIV disease. The presence of bacterial superantigens or cytokines, such as the exotoxins present in many strains of S. aureus have been shown to induce HIV production in human peripheral blood mononuclear leukocyte cultures in vitro, although the precise mechanism is unclear. Thus, HIV infection may increase the risk of S. aureus colonisation and disease and, in turn, infection or colonisation with S. aureus may accelerate the progression of HIV disease to AIDS.