Free secretory component from bovine milk aggregates enteropathogenic Escherichia coli and inhibits binding to intestinal cells

The burden of diarrhoeal disease and the progressive increase in antibiotic resistance to enteric pathogens is a critical area of concern that necessitates exploration of alternative therapeutic approaches. Free secretory component (FSC), derived from human milk, has been shown to inhibit adhesion and invasion of pathogenic bacteria. Cows' milk also contains FSC, but its activity has not yet been characterised. FSC was purified from non-pasteurised and pasteurised bovine milk. The binding properties of purified bovine FSC were investigated against enteropathogenic Escherichia coli (EPEC). Bovine FSC bound to EPEC and facilitated aggregation of the bacteria. FSC also attenuated binding of EPEC to Caco-2 cells. Pasteurisation of milk before extraction of FSC did not affect activity of the FSC. These activities of FSC are consistent with a role in suppressing colonisation of EPEC. Milk extracts enriched for bovine FSC have potential as an alternative to antibiotic therapy for protection against diarrhoeal disease.