Mucosally associated bacterial flora of the human colon: quantitative and species specific differences between normal and inflamed colonic biopsies
Thornley, John P.
Hawkey, Chris J.
- Publisher: Microbial Ecology in Health and Disease
Microbial Ecology in Health and Disease
(issn: 1651-2235, eissn: 1651-2235)
This study quantified and characterised changes to a species level for aerobic and anaerobic bacteria from colonic biopsies of acute ulcerative colitis (UC) comparing them with that of a normal control group. Fresh endoscopic biopsies of the recto–sigmoid region were obtained during flexible sigmoidoscopy from 10 patients suffering an acute attack of UC and a similar number of healthy controls. Quantitative estimation was carried out on selective media for total aerobic, anaerobic, Bacteroides, Bifidobacterium and Lactobacillus spp. (Miles–Misra). Species identification involved gram stain, indole, catalase tests and commercially validated anaerobic, gram-positive and non-enteric fermenting enzyme hydrolysis kits. There was a significant quantitative decrease in growth of Lactobacillus spp. in colitic biopsies (p<0.05). Total aerobic speciation revealed 32 different sub-species with 18 of these found only in UC biopsies. Anaerobic speciation revealed 41 different sub-species with a mean 6.7 species in normal and 4.7 in UC patients. Bacteroides thetaiotaomicron was isolated in significantly increased frequency in UC biopsies (8:10) in comparison with normal (4:10). Our data are consistent with the possibility that a reduction in mucosally associated Lactobacillus bacteria in UC permits proliferation of a large number of potentially pathogenic aerobic species and anaerobic predominance of B. thetaiotaomicron.Keywords: ulcerative colitis, intestinal flora, Lactobacillus, B. thetaiotaomicron.