INCREASED PREVALENCE OF LISTERIA-MONOCYTOGENES IN THE FECES OF PATIENTS RECEIVING LONG-TERM H-2-ANTAGONISTS

Background: Human listeriosis is an uncommon infection caused by the G rampositive organism Listeria monocytogenes. Objective: To investigate the effects of therapeutic gastric acid suppression on faecal isolati on of L. monocytogenes and the incidence of human listeriosis. Methods : Five stool specimens from each of 20 patients on continuous H-2-anta gonist therapy and two faecal samples from each of 47 healthy controls were investigated for the presence of Listeria spp. Results: A higher faecal isolation rate of L. monocytogenes was detected amongst the pa tients (20%) compared with the controls (2.1%) (P<0.025). All subjects with stools positive for Listeria spp. were female, this sex differen ce being significant in the patient group (P<0.0036) compared with con trols. No patient, however, developed listeriosis. Conclusion: Patient s on long-term gastric acid suppressive therapy may be at increased ri sk of faecal carriage of L. monocytogenes.