Estimates of Helicobacter pylori densities in the gastric mucus layer by PCR, histologic examination, and CLOtest.

Helicobacter pylori inhabits the gastric mucus layer of infected persons. A number of investigators have reported the feasibility of detecting H pylori in gastric mucus with polymerase chain reaction (PCR)-based methods. We have established the sensitivity of a simple PCR assay for detecting H pylori in gastric mucus samples and estimate that the density of H pylori organisms in the gastric mucus of untreated patients is approximately 107 to 108 organisms per milliliter. We have similarly estimated the analytic sensitivities of histologic examination and the CLOtest (TRI-MED Specialties, Overland Park, Kan) for detecting H pylori and calculate similar values for the numbers of organisms in the gastric mucus layer. Our data indicate that gastric mucus is a suitable specimen for the detection of H pylori in infected patients, and that PCR-based assays of gastric mucus are significantly more sensitive than histologic testing or the CLOtest for demonstration of H pylori infection.