BACTERICIDAL FACTORS IN GASTRIC-JUICE

Objective: To examine, in human gastric juice, the relationship between gastric acidity, proteases and the growth of organisms commonly implicated in nosocomial infections. The effect of sucralfate on bacterial growth in gastric juice was also studied. Design: Pooled gastric juice from healthy individuals was adjusted to different pH values between 1-7 and organisms commonly implicated in nosocomial pneumonia were used in in vitro experiments. Bacterial growth after exposure to gastric juice at pH values between 1-7 for 10, 60 and 120 min was studied. Growth in gastric juice at the above pH after heat inactivation of proteases, binding of pepsin by pepstatin and the addition of pepsin to gastric juice was investigated in individual controlled experiments. The bactericidal action of sucralfate was assessed in gastric juice at pH values of 1-7. Main outcome measure: The number of organisms present before and after each individual experimental procedure was compared between verum and control experiments. Results: A bactericidal effect was observed after 10 min exposure to gastric juice at a pH below 4 with almost all organisms studied. Inactivation of proteases by heat and of pepsin by pepstatin and the addition of pepsin to gastric juice did not result in different bacterial growth from the control groups. Addition of sucralfate enhanced the bactericidal effect of gastric juice. Conclusion: Gastric juice at pH below 4 has a rapid bactericidal effect on organisms implicated in nosocomial infections, which is independent of proteases and is enhanced by sucralfate.