A Probiotic Bacterium with Activity against the Most Frequent Bacteria and Viruses Causing Pediatric Diarrhea: Bifidobacterium longum subsp. infantis CECT 7210 ( B. infantis IM1 ® )

The second leading cause of death in children under five years old is diarrheal disease. Probiotics, specifically bifidobacteria, have been associated with a reduction in the number of diarrhea episodes and their severity in babies. In this paper, we summarize the preclinical and clinical evidence of the efficacy of subsp. IM1 against various gastrointestinal pathogens using in vitro models, animal models, and clinical studies carried out in our laboratory. The preclinical data demonstrate that IM1 effectively inhibits rotavirus replication (by up to 36.05%) in MA-104 and HT-29 cells and from infection (up to 48.50%) through the production of an 11-amino-acid peptide. IM1 displays the capability to displace pathogens from enterocytes, particularly and , and to reduce the adhesion to the HT29 cells of and . In animal models, the IM1 strain exhibits in vivo protection against rotavirus and improves the clinical symptomatology of bacterial gastroenteritis. A clinical study involving infants under 3 months of age revealed that IM1 reduced episodes of diarrhea, proving to be safe, well tolerated, and associated with a lower prevalence of constipation. IM1 emerges as an effective probiotic, diminishing episodes of diarrhea caused by gastrointestinal pathogens.