[Effect of the administration of killed Lactobacillus acidophilus on the survival of suckling mice infected with a strain of enterotoxigenic Escherichia coli].

After oral administration of 10(2) to 10(5) CFU of Escherichia coli B41 (0101:K 99+:ST+) to 24-48 h old suckling mice (Swiss OF1), a 80 to 100% mortality rate is observed within three days. We compared the effect of the oral treatment with a lyophilized preparation of heat-killed Lactobacillus acidophilus and with sterile water on the mortality rate of newborn mice. In six out of seven assays, the heat-killed L. acidophilus administration extended survival of infected suckling mice (P ranging from 0.019 to less than 0.001). In another test, result was contradictory. A global analysis indicated that the two treatments were statistically different (P less than 0.001). Lactic acid was unable to induce protection.