Anti-infectious activity and prophylactic effects of Bifidobacterium bifidum (strains of human origin), probiotic feeding on enteropathogenic Escherichia coli, in rats (in vivo antagonism)

Abstract

The Bifidobacterium bifidum strain was isolated on MRS medium supplemented with 0.5g/L of cysteine hydrochloride, 2 mg/L of nalidixic acid and 0.1 mg/L of mupirocin. This strain was isolated from breastfed infant faeces. The effectiveness of Bifidobacterium bidum as a probiotic against enteropathogenic Escherichia coli infection was studied using the rat model.
After dissection of all rats, macroscopic and microscopic observations of histological sections of the digestive tract were analysed until 1 and 2 weeks postinfection. The pathogenicity of E. coli, marked by body weight loss and intestinal histopathological changes in the infected group, was significantly reduced in the B. bifidum-treated group. Feeding B. bifidum for 7 days before infection resulted in greater post-challenge feed intake and weight gain and lower faecal levels of enteropathogenic E. coli. A reduced degree of protection against E. coli infection was observed when bifidobacteria were given during the 7 days after E. coli infection.