Fecal bacteriology of colonic polyp patients and control patients.

Feces from 25 subjects with colonic polyps (multiple adenomatous, large single, or single with atypia) and from 25 matched control subjects were studied by detailed quantitative aerobic and anaerobic techniques, using a large battery of culture media and several atmospheric conditions. Over 55% of organisms detected on microscopic count were recovered anaerobically. In several cases, there were significantly different numbers of organisms of specific types recovered from the two different populations studied. However, these differed from organisms with "statistical significance" noted in a previous study from this laboratory involving two different diet groups (Japanese Americans on either a Japanese or a Western diet). Specific differences in bacteriology between groups with different risks of bowel cancer, noted in earlier British studies, were not noted in our present or previous study.

Doxycycline in abdominal surgery.

Twenty patients undergoing urgent or emergency surgical procedures where intra-abdominal infection was suspected were treated with doxycycline hyclate. Wound infections involving anaerobic, aerobic, or facultative bacteria developed in four of 11 patients treated with doxycycline alone. Nine other patients received higher doses of doxycycline plus gentamicin sulfate. Five of these had postoperative infections primarily involving anaerobic organisms. Bacteremia with a doxycycline-resistant Bacteroides fragilis developed in one patient during therapy. Serum levels of doxycycline, even at the higher dosage, were below the minimal inhibitory concentrations (MICs) of a number of potential pathogens isolated at the time of surgery. Doxycycline is not indicated in cases of serious intra-abdominal infection unless the infecting flora are known to be susceptible.

Management of anaerobic infections.

Anaerobic infections are reviewed with emphasis on management. Most anaerobic pulmonary infections respond to penicillin G, even when Bacteroides fragilis (penicillin-resistant) is present. Clindamycin is suitable in penicillin-sensitive patients. Intraabdominal infections have a complex flora usually involving anaerobes, especially B. fragilis. It is desirable to use antimicrobial therapy to cover potential pathogens of all types. Surgical drainage and debridement are extremely important considerations. Anaerobic bacteria were found in 72% of 200 patients with female genital tract infections and were the exclusive isolates in 30%. Surgical therapy is primary, but antimicrobial and anticoagulant therapy are also important. A variety of soft-tissue infections involve anaerobes. Surgery is the major therapeutic approach. Anaerobic endocarditis is uncommon but may be difficult to manage. Chloramphenicol is ordinarily the drug of choice for brain abscess. New antimicrobial agents, which are under investigation and are promising, include new penicillins, new cephalosporins, new tetracyclines, and metronidazole.