An experimental study and a randomized, double-blind, placebo-controlled clinical trial to evaluate the antisecretory activity of Lactobacillus acidophilus strain LB against nonrotavirus diarrhea

OBJECTIVE. Previous studies have shown that selected strains of Lactobacillus have the capacity to antagonize rotavirus-induced diarrhea. However, only a few reports have documented their efficacy against nonrotavirus diarrhea. This study involved an experimental investigation and a clinical trial of the antisecretory activity of Lactobacillus acidophilus strain LB in the context of nonrotavirus diarrhea. METHODS. The activity of a culture of L acidophilus LB or of the lyophilized, heat-killed L acidophilus LB bacteria plus their spent culture medium was tested in inhibiting the formation of fluid-formed domes in cultured human intestinal Caco-2/TC7 cell monolayers infected with diarrheagenic, diffusely adhering Afa/Dr Escherichia coli C1845 bacteria. A randomized, double-blind, placebo-controlled clinical trial of male or female children who were 10 months of age and presented with nonrotavirus, well-established diarrhea was conducted to evaluate the therapeutic efficacy of a pharmaceutical preparation that contains 10 billion heat-killed L acidophilus LB plus 160 mg of spent culture medium. RESULTS. Infection of the cells with C1845 bacteria that were treated with L acidophilus LB culture or the lyophilized, heat-killed L acidophilus LB bacteria plus their culture medium produced a dosage-dependent decrease in the number of fluid-formed domes as compared with cells that were infected with untreated C1845 bacteria. The clinical results show that in selected and controlled homogeneous groups of children with well-established, nonrotavirus diarrhea, adding lyophilized, heat-killed L acidophilus LB bacteria plus their culture medium to a solution of oral rehydration solution shortened by 1 day the recovery time ( ie, the time until the first normal stool was passed) as compared with children who received placebo oral rehydration solution. CONCLUSIONS. Heat-killed L acidophilus LB plus its culture medium antagonizes the C1845-induced increase in paracellular permeability in intestinal Caco-2/TC7 cells and produces a clinically significant benefit in the management of children with nonrotavirus, well-established diarrhea.