Therapeutic potential of probiotics to counter Campylobacter infections: An In vitro and In vivo evaluation in mice

Probiotics, including Lactic Acid Bacteria (LAB), have gained considerable attention due to their potential health benefits for humans and animal livestock. This research aimed to isolate probiotic bacteria of human origin and explore their therapeutic potential against Campylobacter strains, which are recognized as the leading bacterial cause of human gastroenteritis worldwide. A collection of 230 LAB isolates from human stools were screened for the ability of cell free supernatants to inhibit the growth of three strains of C. jejuni and a C. coli . Co -culture and agar -well diffusion assays identified seven isolates with inhibitory activity against Campylobacter ssp., which were characterized as probiotic strains by their tolerance to pH 2 and bile salts, and then identified as Enterococcus spp. using 16S rRNA gene sequencing E. faecalis NM231, E. faecium NM234, E. faecium NM233, E. faecium NM113, E. durans NM232, E. faecalis NM235, and E. faecium NM236. In vivo evaluation was undertaken by the oral administration of selected probiotics to groups of mice prior to challenge with C. jejuni . Histopathological examinations showed challenge groups receiving either mixed probiotics or E. faecium NM234 were protected against C. jejuni -induced jejunal, colonic, ovarian and uterine tissue damage. Immunohistochemical detection of the challenged mice revealed the presence of C. jejuni antigen in jejunal, colonic, ovarian and uterine sections but was absent in mice receiving either mixed probiotics or E. faecium NM234. This study introduces E. faecium NM234 as a promising probiotic against Campylobacter.