Submitted to: Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/19/2008
Publication Date: 5/22/2008
Citation: Jergens, A., Ziemer, C.J., Atherly, T.A., Doyle, R., Wilson-Welder, J., Dorn, A., Henderson, A., Liu, Z., Clausen, K., Wannemuehler, M. 2008. Helicobacter bilis infection alters the spatial distribution of commensal bacteria in colitic C3H/HeN mice [abstract]. In: Proceedings of Digestive Disease Week, May 17-22, 2008, San Diego, California. Interpretive Summary:
Technical Abstract: Background: Infection with Helicobacter bilis triggers the immune reactivity to the resident intestinal bacteria that is associated with the development of mucosal inflammation in defined flora C3H mice. Whether perturbations of the commensal microbiota occur and contribute to Helicobacter-induced colitis has not been systematically investigated. Aim: To study the spatial distribution of a defined bacterial population in normal and inflamed murine intestines using fluorescence in situ hybridization (FISH) and to correlate these observations to the development of colitis. Methods: Gnotobiotic C3H/HeN mice harboring the eight members of the altered Schaedler flora (ASF) were selectively colonized with H. bilis. The ASF and H. bilis bacteria were detected in formalin-fixed colonic tissue sections with FISH using 16S ribosomal RNA-targeted probes for all bacteria (EUB338) and specific probes for the major representatives of the ASF (Bacteroides - BAC303, Eubacterium rectale – Clostridium coccoides group - EREC482, Lactobacillus - LAB158) as well as for the detection of ASF457 and Helicobacter spp. (HEL717). Each section was evaluated by hyperspectral microscopy. The number of bacteria (total and target groups) and their spatial distribution (mucus-scattered, adherent to epithelia, within mucosa) was randomly determined in thirty 60x fields of tissue and compared between control and infected groups. Results: Total bacterial numbers were increased in H. bilis-infected mice compared to healthy mice. The spatial distribution of bacteria in diseased mice was significantly different with higher numbers of Clostridium (ASF356, ASF500, ASF502) and E. plexicaudatum detected in all compartments, but especially in the mucosa-associated population. Invasive Clostridium spp. were found in both superficial and glandular epithelia, often as bacterial clusters. H. bilis was detected in the free mucus in large numbers but was also shown to be adherent and invasive in H. bilis-colonized mice. ASF 457 was abundant in the mucosa-associated population in healthy mice; additionally these mice also had adherent and sporadic invasive Clostridium spp. Conclusions: FISH provided a specific and cultivation-independent means to investigate the structural relationship between bacteria and the colonic mucosa during the development of experimental colitis. Infection of C3H/HeN mice with H. bilis perturbed the spatial distribution of commensal ASF members whereby increased numbers of adherent and invasive Clostridium spp. might participate in the mucosal inflammatory response.