Binding of enteric bacteria to hog gastric mucin

The binding features of enteric bacteria were studied using a model mucin of hog gastric origin. The time requirement of binding is short, it is temperature-independent, but dose-dependent. The binding effectiveness of Escherichia coli, Shigella sonnei and Shigella flexneri, as well as Salmonella minnesota had a narrow range: 1.5-9 germs pro pg of mucin. The bacterial ligand of the binding is certainly not a polysaccharide as proved by the uniform binding of the R-mutant series of S. sonnei and S. minnesota. On the basis of inhibition tests by an outer membrane protein fraction, the ligand may be a common outer membrane protein of the enteric bacteria. The outer membrane proteins encoded by the Shigella-EIEC invasivity plasmids do not take part in this binding. The inhibition by killed bacteria or by their culture supernatants of mucin binding of heterologous species may suggest a non-species specific common ligand, too. Similarly to the mucin utilization, the binding ability also seems to be a general phenomenon among the enteric bacteria.