OmpA variants affecting the adherence of ulcerative colitis-derived Bacteroides vulgatus.

Abstract

To investigate the adhesion factor of Bacteroides vulgatus derived from ulcerative colitis (UC), we isolated B. vulgatus strains from the large intestinal mucosa of UC patients and non-UC individuals, and examined their adherence to tissue-cultured cells. The adherence to tissue-cultured cells in UC-derived strains (36.5 +/- 7.9 %) was higher than that in non-UC-derived strains (13.2 +/- 7.7 %). PCR and sequencing analysis of outer membrane proteins revealed that the strains derived from five of seven (71.4 %) UC patients had ompA genes belonging to either ompA variant type A or B. The adherence rates in Escherichia coli DH5 a transformants with ompA type A variants (33.3 +/- 4.6 %) and type B variants (34.6 +/- 7.1 %) were higher than the rate in those with non-UC ompA (16.4 +/- 4.0 %). Our results suggest that B. vulgatus isolates in the mucosal flora of the large intestine of UC patients have a high frequency of ompA variants and that the variation of ompA variants is one of the factor causing an increase in the adherence of the bacterium.