Detection of Helicobacter pylori in stool specimens by PCR and antigen enzyme immunoassay

Abstract

A highly sensitive seminested PCR assay to detect Helicobacter pylori DNA in feces was developed. PCR with stool specimens and a novel antigen enzyme immunoassay (EIA) for H. pylori detection in feces were evaluated as diagnostic tools and in follow-up with samples from 63 infected and 37 noninfected persons. Infected individuals received eradication therapy followed by endoscopic follow-up 35 days after the start of treatment. At that time, a second stool specimen was obtained from 55 of these patients. Before eradication, the sensitivity of PCR was 93.7% and that of EIA 88.9%. Specificities were 100 and 94.6%, respectively. Of the 55 follow-up specimens, 41 originated from patients from whom H. pylori had been eradicated. Of these, 21 were still positive by PCR and 13 were positive by EIA, indicating that 1 month may be too short a period for follow-up evaluation of stool specimens by these tests.

FIG. 1

Detection of H. pylori DNA in clinical fecal specimens by seminested PCR and analysis of the amplification product (209 bp) by agarose gel electrophoresis and ethidium bromide staining. Lanes: 2 to 8, stool specimens from seven infected patients; 9, negative control using water; 10, positive control with H. pylori cultures (primary PCR template DNA equivalent to six microorganisms); 1 and 11, 100-bp ladder marker. The computer image was generated with Gel Print Workstation (MWG-Biotech, Ebersberg, Germany) and Microsoft PowerPoint 97 software.