Clinical clues to diagnosis of anaerobic infections

The diagnosis of anaerobic infections can be difficult, but it may be expedited by the recognition of certain clinical signs. Predisposing conditions and bacteriologic hints should alert the physician, who may apply diagnostic procedures to ascertain the nature of the pathogens and the extent of the infection. Almost all anaerobic infections originate from the patient's own microflora. Poor blood supply and tissue necrosis lower the oxidation-reduction potential and favor the growth of anaerobic bacteria. Any condition that lowers the blood supply to an affected area of the body can predispose to anaerobic infection. Therefore, trauma, foreign bodies, malignancy, surgery, edema, shock, colitis, and vascular disease may serve as predisposing factors. The source of bacteria involved in most anaerobic infections is the normal, indigenous flora. Anaerobic infections can themselves provide clues to the presence of an underlying medical problem.