Colonization of the stratified squamous epithelium of the nonsecreting area of horse stomach by lactobacilli

Selective adhesion to only certain epithelia is particularly common among the bacterial members of the indigenous microflora of mammals. We have found that the stratified squamous epithelium of the nonsecreting area of horse stomach is colonized by gram-positive rods. The microscopic features of a dense layer of these bacteria on the epithelium were found to be similar to those reported in mice, rats, and swine. Adhering microorganisms were isolated and identified as Lactobacillus salivarius, L. crispatus, L. reuteri, and L. agilis by DNA-DNA hybridization and 16S rRNA gene sequencing techniques. These lactobacilli associated with the horse, except for L. reuteri, were found to adhere to horse epithelial cells in vitro but not to those of rats. A symbiotic relationship of these lactobacilli with the horse is suggested.