Context: Helicobacter pylori commonly infects humans; however, its mode of transmission remains unknown.
Objective: To determine how humans-the primary host for H pylori-shed the organism into the environment.
Design: Controlled clinical experimental study conducted from February through December 1998.
Setting: Clinical research unit of a hospital in northern California.
Patients: Sixteen asymptomatic H pylori-infected and 10 uninfected adults.
Intervention: A cathartic (sodium phosphate) and an emetic (ipecac) were given to all infected subjects and an emetic was given to 1 uninfected subject.
Main outcome measure: Confirmed H pylori isolates cultured from stool, air, or saliva before and after catharsis and emesis and from vomitus during emesis. Isolates were fingerprinted using repetitive extragenic palindromic (REP) polymerase chain reaction and species identity was confirmed by sequencing the 16s ribosomal RNA gene.
Results: All vomitus samples from infected subjects grew H pylori, often in high quantities. Air sampled during vomiting grew H pylori from 6 (37.5%) of the 16 subjects. Saliva before and after emesis grew low quantities of H pylori in 3 (18.8%) and 9 (56.3%) subjects, respectively. No normal stools and only 22 (21.8%) of 101 induced stools grew the organism, although 7 (50.0%) of 14 subjects had at least 1 positive culture (2 stool culture samples were contaminated by fungus and were not included). Fingerprints of isolates within subjects were identical to one another but differed among subjects. No samples from uninfected subjects yielded H pylori.
Conclusions: Helicobacter pylori can be cultivated uniformly from vomitus and, occasionally, from saliva and cathartic stools. The organism is potentially transmissible during episodes of gastrointestinal tract illness, particularly with vomiting.