In vitro studies of porcine lactobacilli for possible probiotic use.

Fourteen strains of lactobacilli isolated from the gut of suckling pigs were identified and studied to determine their susceptibility to antimicrobial feed additives, acid tolerance, adherence to epithelial cells from the porcine intestine and antimicrobial activity. Four strains were identified as Lactobacillus casei subsp. casei, two strains as Lactobacillus rhamnosus as well as Lactobacillus reuteri and three strains as Lactobacillus salivarius. The remaining strains could not be identified. Antimicrobial susceptibility tests showed susceptibility of the lactobacilli to many of the antimicrobial feed additives commonly used in pigs. Strains resistant to cyadox and nourseothricin occurred in high numbers. The tested lactobacilli were acid-resistant at pH 3. Thirteen strains of lactobacilli exhibited strong adherence to epithelial cells from the porcine intestine while one strain was classed as weakly-adherent. All lactobacilli showed inhibitory activity against indicator bacteria in the presence of glucose. Lactate and acetate were the principal final products of glucose fermentation in all strains. Only three strains produced H2O2 in detectable amounts.