New Approach To Controlling E. Coli In Pigs

Roger B. Harvey, a veterinary medical officer in the ARS Food and Feed Safety Research Unit at College Station, leads an effort to develop a mixed culture of beneficial bacteria that's being referred to as "RPCF"--for recombined porcine continuous-flow. Scientists think that RPCF might one day be able to replace today's antibiotic treatments, which are coupled with regulation of ambient temperature, improvement in hygiene and applications of zinc oxide. A growing resistance of E. coli to today's antibiotics makes developing an effective replacement especially important.

Harvey's method involves colonizing young pigs' intestinal tracts with a mixture of beneficial bacteria obtained from other pigs. This helps establish healthy microbial populations in the gut much quicker than would otherwise occur. These "good" bacteria attach to intestinal walls, blocking sites so that disease-causing, "bad" bacteria can't attach and compete for needed nutrients. Some of the colonizing bacteria also produce bactericidal compounds that work against disease-causing pathogens, further reducing their ability to colonize the intestinal tract.

About 35,000 pigs have been tested at four nursery farms and one wean-to-finish operation in five different U.S. regions. These farms had previously been diagnosed with disease caused by the F-18 strain of E. coli. So far, the RPCF mixture of beneficial bacteria has been shown to reduce illness, death and medication costs from E. coli infections, compared to untreated pigs.