Effect of oral genistein and isoflavone-free diet on cecal flora and bacterial translocation in antibiotic-treated mice

Background: There are several reports indicating that the isoflavone genist ein may augment the integrity of the intestinal epithelial barrier as well inhibit bacterial internalization by cultured enterocytes. We speculated th at oral genistein might enhance the integrity of the intestinal epithelial barrier as monitored by the extraintestinal dissemination of intestinal bac teria. Methods: Mice were treated with oral antibiotics to induce cecal bac terial overgrowth accompanied by bacterial translocation of antibiotic-resi stant enterobacteria, especially Escherichia coli. These mice were divided into separate groups that included chow-fed mice orally inoculated either w ith saline, vehicle, or genistein, and mice fed isoflavone-free diet and or ally inoculated with either saline, vehicle, or genistein. Intestinal bacte rial overgrowth was monitored by quantitative culture of excised ceca and b acterial translocation was monitored by quantitative culture of draining me senteric lymph nodes. Results: Mice fed the isoflavone-free diet had decrea sed populations of cecal bacteria compared with chow-fed mice, and bacteria l translocation was reduced in chow-fed mice compared with mice fed isoflav one-free diet. However, bacterial translocation was similar in mice given o ral genistein compared with appropriate control mice. Conclusions: Oral gen istein had no noticeable Effect on bacterial translocation in this model. H owever, the isoflavone-free diet had an antibacterial effect on cecal flora , and the isoflavone-free diet was associated with decreased numbers of cec al bacteria and decreased incidence of bacterial translocation.