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The prevalence of herpesvirus DNA was examined in inflammatory bowel disease tissue. DNA was extracted from resection and biopsy specimens of the large intestine from patients with ulcerative colitis (n = 21), patients with Crohn's disease (n = 29), and patients with noninflammatory bowel disease (controls) (n = 21). The nested polymerase chain reaction was used to detect viral DNA using primer pairs specific for either cytomegalovirus (CMV), herpes simplex virus 1 (HSV1), human herpesvirus 6 (HHV6), varicella zoster virus (VZV), or Epstein Barr virus (EBV). HSV1 and VZV DNA were not detected in any of tissue samples. There was a high prevalence of CMV (81%), HHV6 (76%), and EBV (76%) DNA in ulcerative colitis tissue compared to Crohn's disease tissues (CMV 66%, HHV6 45%, EBV 55%). Control tissue had a relatively low frequency of CMV (29%) and EBV (19%) DNA but a prevalence of HHV6 DNA similar to that of ulcerative colitis (86%). However, the simultaneous presence of HHV6 and CMV and/or EBV DNA in ulcerative colitis tissue (76%) was much greater than in either Crohn's disease tissues (38%) or control tissue (29%) (P < 0.05). There was a low prevalence of CMV, HHV6, and EBV DNA in peripheral blood mononuclear cells from all patient groups. CMV and EBV are capable of reactivating HHV6: the high prevalence of coexistent HHV6 infection with either or both of these two viruses in ulcerative colitis tissue suggests that they may play a synergistic role in the pathogenesis of this disease.

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Edinburgh EH8 9AGBiopsy samples of mucosa were taken during colonoscopy from the proximal colon and rectum of 12 patients, six with ulcerative colitis (UC) and six with non-inflammatory conditions. After anaerobic transport to the laboratory, biopsy specimens were examined by quantitative bacteriological culture on selective and non-selective media for total aerobic count, total anaerobic count, Bacteroides spp., lactobacilli, bifidobacteria and asaccharolytic, lactic acid producers. Isolates of the genus Bacteroides were identified to species level. Counts from proximal colonic and rectal biopsy samples in the same patient were not significantly different. Viable aerobic counts (aerobes and facultative organisms) ranged from 2.4 X lo3 to 1.3 X lo6 cfu/sample biopsy (5.6 mg) and total anaerobic counts were 10-lo2 times higher at (1.4 X 105)-(3 X lo7) cfu/sample. Bacteroides spp. predominated at both sites (range 8.6 X lo4 to 1.4 X lo7 cfu/sample), comprising 66% of total counts from proximal colon (range in individual patients 31-80%) and 68.5% from rectum (range 38-91 YO). Lactobacilli were isolated from eight biopsy samples from five patients, counts ranging from 3.6 X lo2 to 1 X lo5 cfu/sample; bifidobacteria were isolated from both sites from 10 of the 12 patients, counts ranging from 50 to 1.8 X lo6 cfu/sample. From the 24 biopsy samples, 235 isolates representing 11 species of Bacteroides were identified. For any individual patient, only a few species (2-7; mean 4.4) of Bacteroides were found, with just one or two species predominating. B. vulgatus was cultured from both samples of seven patients (where it was the major isolate in four) and from single samples of two others; B. fragilis was cultured from both sites in six patients, being the major isolate in one patient and second commonest in three, but was not detected in the other six; the majority of other isolates were B. rnerdae/dstasonis, B. ovatus, B. thetaiotaomicron and B. uniformis. B. thetaiotaomicron was isolated from both biopsy samples in all three UC patients with active inflammation (16 of the 60 isolates from these patients) but from only four of the other 18 samples from non-inflamed colonic mucosa (nine of 175 isolates).

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