DIAGNOSIS OF HELICOBACTER-PYLORI INFECTION BY MEANS OF A POLYMERASE CHAIN-REACTION ASSAY FOR GASTRIC-JUICE ASPIRATES

A polymerase chain reaction (PCR) assay for Helicobacter pylori was developed with use of primer sequences from the ureA structural gene coding for the small subunit of urease. The PCR amplification was 100% specific for H. pylori in tests with 40 stock isolates of this species and with 30 control organisms, including two species of urease-producing Helicobacter. Thirty-four dyspeptic patients were evaluated by culture and histologic assessment of antral biopsy samples as well as by PCR of gastric juice aspirates. In 26 of the 34 patients, infection with H. pylori was diagnosed by culture and histology. PCR correctly identified 25 of these 26 patients. All eight patients with negative cultures and histologic findings also had negative PCR results. In this group of patients, therefore, PCR had a sensitivity of 96% and a specificity of 100%. Thus PCR of gastric juice aspirates can be used to diagnose H. pylori infection. This information is important since gastric juice can be aspirated through a nasogastric tube without gastroduodenoscopy. In addition, since clinical samples can be collected at one institution and mailed to a laboratory at another without compromising the outcome of the test, diagnostic PCR is accessible even to those clinicians at whose institutions the technology required for the procedure is not available.