Transient bacteremia and endocarditis prophylaxis. A review.
Transient, usually asymptomatic bacteremia occurs in a wide variety of procedures and manipulations, particularly those associated with mucous membrane trauma. It may also occur with such daily functions as tooth brushing and bowel movements. These brief bacteremias are especially common in tooth extraction and other dental procedures. Although numerical risk is uncertain, these bacteremias can occasionally give rise to infective endocarditis in the susceptible patient. While no proof exists that antibiotics given prior to procedures causing bacteremia prevent endocarditis in humans, experimental evidence in rabbits supports their use. Therefore, in situations where bacteremia is highly predictable, it would seem wise to administer prophylactic antimicrobials. Procedures in the susceptible host where prophylactic antibiotics seem prudent include dental manipulations and urinary tract instrumentation. Whether patients with acquired valvular or congenital heart disease who are to undergo abdominal surgical procedures should routinely receive prophylactic antibiotics is unclear. However, until the incidence of transient bacteremia associated with various abdominal procedures is further defined, endocarditis-prone patients should probably receive prophylaxis. Furthermore, patients with prosthetic valves who are subjected to upper gastrointestinal endoscopy, sigmoidoscopy, liver biopsy, or barium enema should also probably have antibiotic pretreatment. For dental procedures and for upper gastrointestinal endoscopy in patients with prosthetic valves, a combination of penicillin and streptomycin or vancomycin alone is recommended. For urinary tract instrumentation in all patients and for sigmoidoscopy, liver biopsy, or barium enema in patients with prosthetic valves, prophylaxis should be with ampicillin and gentamicin or vancomycin and gentamicin.