Host factors predisposing to anaerobic infections.

Factors that predispose to infection in general, of course, may predispose to infection with anaerobes. Included in this category are diabetes mellitus, neutropenia, hypogammaglobulinaemia, malignancy, splenectomy, collagen vascular disease, cytotoxic drug therapy, corticosteroid therapy and other immunosuppression. However, even with these situations there may be certain, more specific, associations: anaerobic cholecystitis and anaerobic osteomyelitis in diabetics, neutropenic colitis, and the increased incidence of local anaerobic infections associated with carcinoma of the lung, colon and uterus. Conditions that lead to decreased redox potential more specifically predispose to infection with anaerobes. Included in this category are obstruction and stasis, tissue anoxia, tissue destruction, vascular insufficiency, prior aerobic infection, burns, foreign body implantation, and calcium salts in a wound (in association with fractures). Other specific clinical situations that predispose to anaerobic infections include leukaemia; oral, gastrointestinal, and female pelvic surgery; trauma at other sites; childbirth; aspiration pneumonia; human and animal bites; and therapy with agents with poor activity against anaerobes (e.g. aminoglycosides, quinolones). AIDS patients appear to be predisposed to severe periodontal disease and its complications.