Bacteriological examination was made of bile from 119 patients with cholecystitis and/or cholelithiasis. In an initial series of 50 samples from the gallbladder, cultivated aerobically and anaerobically in thioglycollate broth, only aerobes were isolated from 48% of the patients. In a 2nd series of 69 patients, the anaerobic techniques were more adequate: sampling by puncture with oxygen exclusion, microbiological processing within 10 min, and use of anaerobically stored media. The results of aerobic cultivation were similar in the 2 series, but in the latter 18% of the bacterial strains were anaerobes, alone or in combination with aerobes. The anaerobes were fairly equally distributed between the genera Bacteroides, Clostridium and Peptostreptococcus (2, 3 and 4 isolates, respectively). The recovery rates of anaerobes compare favorably with those of other similar studies. Of patients suspected of having only non-inflammatory conditions with cholelithiasis, 28% had positive cultures, indicating that bacteria are often present together with calculi, even without clinical symptoms of infection. The consequence is that bile system operations should always be considered to be potentially infected and require careful operative technique to avoid spilling of bile on wound surfaces. There was a significant association between recovery of bacteria and patient age. The administration of antibiotics before sampling did not significantly alter the incidence of bacterial recovery. Postoperative infections occurred in only 7% of the patients. The antibiotics that inhibited most of the bacteria isolated were ampicillin, cephalosporins and gentamycin.
