In vitro attachment of Salmonella typhimurium to chicken cecal mucus: effect of cations and pretreatment with Lactobacillus spp. isolated from the intestinal tracts of chickens.

The attachment of radiolabeled Salmonella typhimurium 333/O cells to immobilized cecal mucus from specific-pathogen-free leghorn chickens was determined in the presence of D-mannose. The attachment of S. typhimurium was inhibited by the chelating agents EDTA and citrate and by lanthanum but was enhanced in the presence of the calcium, barium, and manganese divalent cations. Summary findings of the effect of lectins are included. Attachment of lactobacilli, previously isolated from the intestines of chickens, to mucus was also enhanced by calcium and inhibited by chelators. The pretreatment of immobilized mucus with portions of cultures of five of eight strains of lactobacilli inhibited subsequent attachment of the S. typhimurium strain. Spent culture supernatant fluid and/or washed cells from these cultures inhibited attachment, and inhibition was enhanced by preheating the cells or supernatant fluid at 80 degrees C. Results indicate that S. typhimurium mucus attachment not involving mannosyl-dependent receptors is influenced by presence of cations. Lactobacillus spp. isolated from the intestinal tracts of chickens produce cellular and cell-free components that inhibit this form of attachment to chicken intestinal mucus.