Fecal and Oral Shedding of H. pylori
Several important unresolved questions about Helicobacter pylori, the causative agent of almost all non-NSAID related ulcers and a likely cause of gastric cancer, remain unanswered. The path by which H. pylori leaves a host to enter the environment, the environmental location, method of human acquisition, and individual susceptibility to this organism are uncertain. This study was directed to learn, by using polymerase chain reaction (PCR) testing, the frequency of H. pylori in saliva, stool, and vomitus of infected volunteers. Immunomagnetic separation (IMS)-PCR was chosen as the detection method because of its superior ability to identify live organisms.
After sodium phosphate-induced catharsis, ipecac-induced emesis, and volitional saliva expectoration, H. pylori detection by IMS-PCR was performed (n = 16).
Stool culture obtained prior to catharsis was culture negative in all 16 patients, but positive in 5/16 using IMS-PCR. Post-cathartic stools were H. pylori-positive in 11/16 subjects by IMS-PCR, but only 50% of specimens were culture-positive. All vomitus samples from infected person were culture-positive as well as IMS-PCR positive. Saliva was culture-positive in only 18.8% of subjects but IMS-PCR positive in 43.8%.
Despite the ready retrieval of H. pylori from saliva, there is little evidence of oral-oral transmission (e.g., the H. pylori strain present in married couples is rarely concordant and, thus far, studies of treated patients, whose infected partners are not treated, do not show significant risk of reinfection).
Saliva, stool, and vomitus all harbor H. pylori, which might serve as sources of transmission. Since up to half of middle-aged adults have been infected, the question might best be reframed to seek how the other half remain uninfected.
Parsonnet J, et al. JAMA 1999;282: 2240-2245.