Control of diarrhea and intestinal damage caused by enteropathogenic Escherichia coli using infant formula fermented with Lacticaseibacillus paracasei BMK2005: in vitro and in vivo evidences.

Lacticaseibacillus paracasei BMK2005 (L. paracasei BMK2005) was isolated from the feces of a 1-year-old healthy Algerian infant. This strain, identified by 16S rDNA sequencing and API system, has demonstrated a remarkable antibacterial activity against enteropathogenic Escherichia coli in vitro and in vivo. In addition, this strain was shown to survive in a variety of environmental conditions that mimic the gastrointestinal tract conditions such as different pH values, bile salts and digestive enzymes. Moreover, L. paracasei BMK2005 was γ-hemolytic and sensitive to various antibiotics, supporting a safe characteristic for its application. Next, the anti-EPEC activity was then evaluated in an infant formula composed of 50% whey and 50% skim milk. A significant reduction in EPEC counts was observed after 24 h of incubation. These inhibitory properties were confirmed in an animal model using ten holoxenic rabbits made diarrheic by EPEC ingestion. L. paracasei BMK2005 was able to reduce the number of EPEC in the feces of diarrheic animals treated with the milk formula fermented by this strain. To support this study, histopathologic sections of the intestines of treated and untreated rabbits revealed clear injury in the case of animals infected with EPEC, an effect characterized by damaged villosities, while normal villosities were observed in samples from control or treated animals, delineating the protective effect of L. paracasei BMK2005.