Biological evaluation of a methanol-soluble, heat-stable Escherichia coli enterotoxin in infant mice, pigs, rabbits, and calves

Abstract

E. coli P16 produces 2 heat-stable toxins (ST) with differing biological activity. The toxins were separated by methanol extraction, and the 1st, STa, was methanol soluble, partially heat stable, active in neonatal piglets (1-3 days old) and infant mice, but inactive in weaned pigs (7-9 wk old); the 2nd, STb, was methanol insoluble, active in weaned pigs and rabbit ligated loops, but inactive in infant mice. Use of suckling mice as indicators of ST production will probably fail to identify certain ST-producing strains.