Phosphatidylserine found in intestinal mucus serves as a sole source of carbon and nitrogen for salmonellae and Escherichia coli

Abstract

Salmonella choleraesuis (a pig pathogen), Salmonella typhimurium (a virulent strain in mice), and three strains of Escherichia coli (including a human enterohemorrhagic strain, a human urinary tract isolate, and a human fecal isolate) grew as well in vitro utilizing the lipids derived from mouse cecal mucus as the sole source of carbon and nitrogen as they did in mouse crude cecal mucus. Further analysis of the total lipid extracts of mucus dialysates showed that the acidic lipid fraction supported growth nearly as well as the total lipid fraction. Interestingly, among the many purified acidic lipids from mucus which were tested and analyzed, including several phospholipids, only phosphatidylserine was found to support the growth of all of these enteric bacteria, including Salmonella milwaukee, a human pathogen. The possible role of growth on pure phosphatidylserine in the pathogenesis of salmonellae is discussed.