Degradation of intestinal glycoproteins by pathogenic Shigella flexneri

Abstract

Intestinal mucin glycoproteins were examined for their ability to sustain growth of pathogenic shigella. Inoculation of germfree cecal mucin glycoproteins with Shigella flexneri 4b resulted at 48 h in a 940-fold increase in the enteropathogen concentration. Investigation in vitro of enzymatic degradation by the pathogen led to the identification of a blood group B-degrading glycosidase produced by the bacteria. In in vivo experiments, fecal supernatants of mice monocontaminated with S. flexneri 4b contained an alpha-galactosidase active against the p-nitrophenyl-glycoside. This fecal alpha-galactosidase peaked 5 days after shigella contamination, showing 2.8 +/- 1.4 mU of enzyme activity per mg of protein. Contaminated fecal supernatants similarly destroyed the blood group B reactivity of cecal mucin glycoproteins. These data suggested that S. flexneri 4b could proliferate within ileocolonic environment by enzymatically degrading mucin glycoprotein sugars.