Use of competitive exclusion to control enterotoxigenic strains of Escherichia coli in weaned pigs

Mortality and morbidity associated with Escherichia coli cause economic losses to the swine industry. Enterotoxigenic strains of E. coli affecting nursery-age pigs have become more difficult to treat because of increased antibiotic resistance, and alternatives to antibiotics are currently being sought. Our laboratory developed a defined culture of commensal bacteria of porcine gastrointestinal tract origin, maintained it in continuous-flow culture for 3 yr, and designated it as RPCF. Laboratory studies have shown that RPCFtreated pigs had decreased mortality and bacterial shedding compared with controls when challenged with enterotoxigenic strains of E. coli. The objective of the present study was to evaluate the practicality, safety, and efficacy of RPCF to protect nursery-age pigs in commercial swine operations from field challenge by enterotoxigenic strains of E. coli. In field studies involv