Stimulation of the development of bacteriostatic activity of guinea-pig milk against Escherichia coli.

The bacteriostatic activity of guinea-pig milk against various strains of Escherichia coli has been examined. Milk collected from sows suckling normal young was usually inactive, but the activity of milk from sows suckling young which had been orally infected with Esch. coli was significantly increased. The increase occurred in 2 phases: the first was found as early as 24 h after infection, suggesting stimulation via the teat canal (diathelic), but lasted only 2-3 days; the second occurred from 10 days post-infection onwards, and lasted until the end of lactation. The occasional bacteriostatic activity of milk from sows with normal young was not correlated with the presence in the faeces of naturally occurring Enterobacteriaceae, including Esch. coli.