Some Light is Shed on the Transmission of Helicobacter pylori
Abstract & CommentarySynopsis: This study indicates that Helicobacter pylori can be cultivated from vomitus and occasionally from saliva and cathartic stools of infected subjects, suggesting that the organism is potentially transmissible during gastrointestinal illness, especially with vomiting.
Source: Parsonnet J, et al. Fecal and oral shedding of Helicobacter pylori from healthy infected adults. JAMA 1999; 282:2240-2245.
The method of transmission of H. pylori has been unknown, with the uncertainty related to questions of how the organism leaves its host and enters the environment, where in the environment the organism resides, when do people acquire the infection, and are all people susceptible to infection? Despite epidemiological evidence supporting direct person-to-person transmission, the manner of transmission is unknown.
Sixteen healthy, asymptomatic volunteer subjects found to be positive for H. pylori by breath test and 10 H. pylori-negative volunteers were studied. Stool, vomitus after overnight fast, saliva, and air samples from 0.3 m and 1.2 m were analyzed from the infected subjects, and uninfected subjects had stool and saliva samples analyzed for growth of H. pylori.
Stools collected prior to administration of a cathartic from all infected and uninfected subjects were negative by culture for H. pylori. Cathartic-induced stools grew H. pylori in 21.8%. All vomitus samples from infected subjects grew H. pylori, often in high quantities. Samples of air during vomiting grew H. pylori from 37.5% of the 16 subjects, while saliva before and after emesis grew low quantities of H. pylori in 18.8% and 56.3% of subjects, respectively. H. pylori was not obtained from any of the uninfected subjects.
The study indicates that H. pylori can be cultured from vomitus and stools of healthy H. pylori-infected persons and H. pylori was excreted into the environment by all infected subjects. It is remarkable that so many persons remain uninfected and perhaps declining incidence of gastroenteritis is contributing to the decline of H. pylori infection in industrialized countries.
Comment by Beverly P. Wood, MD
H. pylori increases the risk of peptic ulcers and distal gastric cancer in those who carry the organism. H. pylori is apparently acquired early in life and remains a long-term organism in the stomach. The origin of H. pylori infection and its transmission has been less well understood, although it is known that risk factors include crowding in childhood, a mother who carries H. pylori, siblings (especially older siblings), and unclean water source. The incidence of H. pylori is decreasing in countries without crowding and with cleaner water supplies. Suggestion of person-to-person transmission of H. pylori in both diarrheal stools and vomitus helps to explain the transmission. Perhaps with improved control of transmission, fewer cases of peptic ulcer disease will be related to H. pylori infection. What will we search for to explain ulcers then?
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