Biofilm competency of Desulfovibrio vulgaris Hildenborough facilitates colonization in the gut and represses adenoma development in a rat model of colon cancer

Abstract Sulfate-reducing bacteria including Desulfovibrio spp. have been associated with suppression of tumor incidence and growth of colorectal cancer (CRC) in human and animal studies. However, other studies suggest that Desulfovibrio spp. are decreased in healthy controls. To address this dichotomy, we treated a rat model of CRC with biofilm-forming and biofilm-deficient strains of Desulfovibrio vulgaris Hildenborough (DvH) to evaluate tumor development. The biofilm-forming DvH stably colonized the rat colon after neonatal administration. Contrarily, the biofilm-deficient strain was undetectable one-week after treatment. The colonic adenoma burden was significantly reduced in the biofilm-forming DvH treated rats compared to the control and biofilm-deficient group. In contrast, known mucin degrading bacteria were increased in the control groups correlating with increased expression of the colonic mucin gene, MUC2, and DNA repair genes MSH2, ATM, and MGMT. This indicates that sulfate reducing biofilm forming bacteria can colonize and protect the colonic epithelium from adenoma initiation.