Bacteria associated with the gastric epithelium of neonatal pigs.

Light and electron microscopy showed lactobacilli and, to a lesser degree, streptococci to be closely associated with the squamous area of the pig stomach known as the pars esophagea. Several different types of extracellular layers were seen on bacteria attached to the epithelial surface. The total number of bacteria per square centimeter did not change with age up to 10 days, and there was no effect of weaning at 2 days. Lactobacillus fermentum, L. salivarius, and Streptococcus salivarius were isolated more frequently from sucking pigs than from those that were early weaned, whereas the reverse was true of L. acidophilus and S. bovis. All isolates recovered from washed macerated pars esophagea adhered to pig esophageal epithelial cells when tested in vitro.