EFFECT OF LACTOBACILLUS-REUTERI ON INTESTINAL RESISTANCE TO CRYPTOSPORIDIUM-PARVUM INFECTION IN A MURINE MODEL OF ACQUIRED-IMMUNODEFICIENCY-SYNDROME

Efficacy of Lactobacillus reuteri as a probiotic for the control of Cr yptosporidium parvum infection was evaluated in C57BL/6 female mice th at were immunosuppressed by intraperitoneal inoculation with the LP-BM 5 leukemia virus. Four months after inoculation, mice developed lympha denopathy, splenomegaly, and susceptibility to C. parvum infection. Af ter daily prefeeding with L. reuteri (10(8) cfu/day) for 10 days, mice were challenged with 6.5 X 10(6) C. parvum oocysts and fed L. reuteri during the entire study. Mice supplemented with L. reuteri and challe nged with C. parvum cleared parasite loads from the gut epithelium. Ho wever, unsupplemented animals developed persistent cryptosporidiosis a nd shed high levels of oocysts in the feces. L. reuteri feeding increa sed its colonization of the intestinal tract, which was inversely rela ted to the fecal shedding of oocysts. These findings suggest that L. r euteri may help prevent C. parvum infection in immunodeficient subject s.