The protective role of gastric acidity in neonatal bacterial translocation

The acid environment of the stomach serves as an important defense against intestinal colonization by potentially pathogenic bacteria. The purpose of this study was to examine the effect of increased gastric pH on bacterial translocation in a neonatal rabbit model. Fifty-nine rabbit pups were delivered by cesarean section and randomly divided into normal acid (NA) and reduced acid (RA) groups. All were gavage fed and challenged with Enterobacter cloacae, 1 x 10(6) CFU/mL. The RA group received ranitidine, 20 mg/kg/d with all feeds. Gastric pH was measured by pH probe before and 4 hours after bacterial challenge. Mesenteric lymph node (MLN), spleen, liver, midjejunum, and cecum were harvested for culture at 72 hours. Gastric pH in the RA group was significantly increased before and 4 hours after the bacterial challenge. The incidence of bacterial translocation to the MLN, spleen, and liver was significantly higher in the RA group. Log cecal and jejunal colony counts were significantly increased in the RA animals. The authors conclude that the gastric acidity is protective against intestinal colonization and translocation of potentially pathogenic bacteria in this neonatal rabbit model.