Competitive exclusion of Salmonella enteritidis in chicks by treatment with a single culture plus dietary lactose.

Oral inoculation of lactose utilizing cecal bacteria plus 2.5% lactose treatments were tested in young chicks for protective efficacy against infection by Salmonella enteritidis. One-day-old chicks were treated with cecal bacteria upon arrival and challenged orally on day 3 with 10(4)-10(6) cfu S. enteritidis. A single culture identified as Escherichia coli O75:H10 was found significantly more protective than all other isolates tested. This isolate excreted a metabolite(s) in vitro that was inhibitory towards the growth of S. enteritidis. The results of this study indicate that discovery of protective strains can be facilitated by screening isolates in vitro for lactose utilization and growth inhibition of S. enteritidis before administration of treatment.