The assessment of faecal flora in patients with inflammatory bowel disease by a simplified bacteriological technique.

A semi-quantitative bacteriological method was used to study faecal flora in 42 patients with Crohn's disease, 37 with ulcerative colitis and 21 healthy controls. Faecal homogenates were plated on primary isolation plates by a technique that allowed the growth of various microbial isolates to be assessed on a visual 1(+)-5+ score. This method was first calibrated against a standard quantitative bacteriological technique, which confirmed the reliability and reproducibility of the results obtained by the simpler method. Patients with clinically active Crohn's disease (22) had significantly higher total aerobe scores than patients with quiescent disease (20) (p less than or equal to 0.006) or ulcerative colitis (p less than or equal to 0.04) or normal controls (p less than or equal to 0.02). The scores of Escherichia coli were parallel to those of total aerobes. Lactobacillus and bifidobacteria scores were significantly reduced in patients with Crohn's disease compared to those with ulcerative colitis and controls. The anaerobic flora in both Crohn's disease and ulcerative colitis was indistinguishable from that of controls. Bacteroides vulgatus and B. fragilis were the predominant bacteroides in all groups. Patients with ulcerative colitis, regardless of disease activity, harboured faecal flora that did not differ from that of normal controls. The abnormal faecal flora in Crohn's disease did not correlate with established clinical and laboratory indicators of disease activity.