Molecular detection of Helicobacter pylori in rapid urease test-negative gastric biopsy samples

Background: Accurate detection of Helicobacter pylori remains challenging in dyspeptic patients because urease-based assays may be negative in low-density or patchy infection. The study aims to evaluate biopsy-based nested PCR targeting the ureA gene for detection of H. pylori, with emphasis on molecular detection among rapid urease test (RUT)-negative gastric biopsies. Methods: This cross-sectional descriptive study enrolled 130 dyspeptic adults undergoing upper gastrointestinal endoscopy at the Department of Microbiology, Chittagong Medical College, Chattogram, in collaboration with the Department of Gastroenterology, Chittagong Medical College Hospital, over a one-year period from January 2023 to December 2023. Two antral biopsies were collected per patient, one for RUT and one for Nested PCR targeting ureA. Results: The cohort included 76 males (58.46%) and 54 females (41.54%), with the largest age stratum 20-40 years. Endoscopy was normal in 52 (40.0%) and abnormal in 78 (60.0%), most commonly antral gastritis (31.5%). Nested PCR was positive in 97/130 (74.6%), RUT was positive in 87/130 (66.9%). Among RUT-negative cases (n=43), nested PCR detected H. pylori DNA in 12 (27.9%); among RUT-positive cases (n=87), PCR was positive in 85 (97.7%). RUT and PCR were strongly associated (χ²=74.18, p<0.0001). Using RUT as comparator, PCR Sensitivity was 97.70%, Specificity 72.09%, positive predictive value (PPV) 87.63%, negative predictive value (NPV) 93.94%, accuracy 89.23%. Conclusions: Nested ureA PCR demonstrated high detection and identification even with infections among RUT-negative biopsies, supporting its adjunct value in tertiary-care workflows.