The role of anaerobic bacteria in human infections.

Anaerobes are generally accepted as clinically important pathogens. Although they are found on most mucocutaneous surfaces, anaerobic bacteria are especially abundant in the upper and lower respiratory tracts, gastrointestinal tract, and female genital tract. They are involved in infections such as chronic sinusitis, aspiration pneumonia, lung abscess, intra-abdominal abscess, bacterial vaginosis, decubitus ulcer, and bite wounds. Depending on the type and location of the infection, treatment may involve surgical drainage and a multiple antibiotic regimen that provides protection against both anaerobes and gram-negative aerobes. Penicillin was the drug of choice for anaerobic infections, but its inactivity against most penicillinase-producing anaerobes has made it less useful for empiric therapy. Clindamycin, with its proven activity against anaerobic infections, is the current drug of choice. Clindamycin is particularly effective against upper and lower respiratory tract infections and infections of the female genital tract.