In vivo evaluation of lactobacillus species as probiotics in the control of shigellosis in infants

Fermented cereal gruel is a popular weaning food in the West African zone, especially Nigeria. Lactobacillus acidophilus and Lactobacillus pentosus have been found to be the major fermenting organisms. The possible use of these as probiotics in the control of Shigellosis was investigated. They were used as starter cultures in pure and combined forms (mixed cultures) in the fermentation process, but spontaneous fermentation was also carried out. The fermented cereal samples were used as feeds for albino mice (neonates) for 8 days, which were immediately challenged with cells of Shigella dysenteriae - the causative agents of Shigellosis. Survival rates of 100%, 90%, and 80% were found in those fed with cereals fermented with the mixed culture, L. acidophilus and L. pentosus, respectively, after 20 days. The cereal feed that was fermented spontaneously gave only a survival rate of 33.3%, while the breast-fed mice, which served as control, had no survivors. The Shigella cells recovered in the feces were counted in both test mice and the control. Cells were not detected after the 6th day in all mice fed with the starter-culture fermented samples, although there was a recovery of cells till the 15th day in mice fed with spontaneously fermented samples. A geometric increase in the Shigella cell count was observed in the control mice and all died within three days. This result suggests the possible use of Lactobacillus starter cultures, especially of mixed cultures in the weaning food of infants, against Shigellosis, a common form of diarrhea in children in developing countries.