Clinical Trials Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 21, 2018; 24(27): 3021-3029
Published online Jul 21, 2018. doi: 10.3748/wjg.v24.i27.3021
New fecal test for non-invasive Helicobacter pylori detection: A diagnostic accuracy study
Andrea Iannone, Floriana Giorgio, Francesco Russo, Giuseppe Riezzo, Bruna Girardi, Maria Pricci, Suetonia C Palmer, Michele Barone, Mariabeatrice Principi, Giovanni FM Strippoli, Alfredo Di Leo, Enzo Ierardi
Andrea Iannone, Michele Barone, Mariabeatrice Principi, Alfredo Di Leo, Enzo Ierardi, Section of Gastroenterology, Department of Emergency and Organ Transplantation, University of Bari, Bari 70124, Italy
Andrea Iannone, Department of Emergency and Organ Transplantation, University of Bari, Bari 70124, Italy
Floriana Giorgio, Bruna Girardi, Maria Pricci, THD SpA, Correggio (Reggio Emilia) 42015, Italy
Francesco Russo, Giuseppe Riezzo, National Institute of Gastroenterology, “S De Bellis” Research Hospital, CastellanaGrotte (Bari) 70013, Italy
Suetonia C Palmer, Department of Medicine, University of Otago Christchurch, Christchurch 8011, New Zealand
Giovanni FM Strippoli, Diaverum Academy, Lund 22229, Sweden
Giovanni FM Strippoli, Diaverum Medical Scientific Office, Lund 22229, Sweden
Giovanni FM Strippoli, Sydney School of Public Health, University of Sydney, Sydney NSW-2000, Australia
Giovanni FM Strippoli, Section of Nephrology, Department of Emergency and Organ Transplantation, University of Bari, Bari 70124, Italy
Author contributions: Iannone A, Di Leo A and Ierardi E designed the research; Iannone A, Giorgio F, Russo F, Riezzo G, Girardi B, Pricci M and Principi M performed the research; Giorgio F, Russo F, Riezzo G, Girardi B and Pricci M collected the data; Iannone A analyzed the data; Iannone A, Palmer SC, Strippoli GF and Ierardi E wrote the paper; Palmer SC, Barone M, Principi M, Strippoli GF, Di Leo A and Ierardi E critically revised the manuscript for important intellectual content.
Institutional review board statement: The study was performed in agreement with the ethical guidelines of the Declaration of Helsinki and the protocol was approved by the local Ethics Committee (Ospedale Consorziale Policlinico, Bari, protocol number 74413).
Informed consent statement: All participants gave written informed consent before inclusion in the study.
Conflict-of-interest statement: Alfredo Di Leo is an advisory board member of THD Spa. Floriana Giorgio, Bruna Girardi and Maria Pricci are employees of THD Spa. All other authors declare no financial support or conflict of interest.
Data sharing statement: The raw data and SAS code used for all analyses are available from the corresponding author.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Enzo Ierardi, MD, Associate Professor, Section of Gastroenterology, Department of Emergency and Organ Transplantation, University of Bari, Piazza Giulio Cesare 11, Bari 70124, Italy. e.ierardi@virgilio.it
Telephone: +39-80-5593088 Fax: +39-80-5593088
Received: April 28, 2018
Peer-review started: April 28, 2018
First decision: June 11, 2018
Revised: June 12, 2018
Accepted: June 27, 2018
Article in press: June 27, 2018
Published online: July 21, 2018
Abstract
AIM

To assess the diagnostic accuracy of a new fecal test for detecting Helicobacter pylori (H. pylori), using13C-urea breath test as the reference standard, and explore bacterial antibiotic resistance.

METHODS

We conducted a prospective two-center diagnostic test accuracy study. We enrolled consecutive people≥ 18 years without previous diagnosis of H. pylori infection, referred for dyspepsia between February and October 2017. At enrollment, all participants underwent 13C-urea breath test. Participants aged over 50 years were scheduled to undergo upper endoscopy with histology. Participants collected stool samples 1-3 d after enrollment for a new fecal investigation (THD fecal test). The detection of bacterial 23S rRNA subunit gene indicated H. pylori infection. We also used the index diagnostic test to examine mutations conferring resistance to clarithromycin and levofloxacin. Independent investigators analyzed index test and reference test standard results blinded to the other test findings. We estimated sensitivity, specificity, positive (PPV) and negative (NPV) predictive value, diagnostic accuracy, positive and negative likelihood ratio (LR), together with 95% confidence intervals (CI).

RESULTS

We enrolled 294 consecutive participants (age: Median 37.0 years, IQR: 29.0-46.0 years; men: 39.8%). Ninety-five (32.3%) participants had a positive13C-urea breath test. Twenty-three (7.8%) participants underwent upper endoscopy with histology, with a full concordance between 13C-urea breath test and histology in detecting H. pylori infection. Four (1.4%) out of the 294 participants withdrew from the study after the enrollment visit and did not undergo THD fecal testing. In the 290 participants who completed the study, the THD fecal test sensitivity was 90.2% (CI: 84.2%-96.3%), specificity 98.5% (CI:96.8%-100%), PPV 96.5% (CI: 92.6%-100%), NPV 95.6% (CI: 92.8%-98.4%), accuracy 95.9% (CI: 93.6%-98.2%), positive LR 59.5(CI: 19.3-183.4), negative LR 0.10 (CI: 0.05-0.18). Out of 83 infected participants identified with the THD fecal test, 34 (41.0%) had bacterial genotypic changes consistent with antibiotic-resistant H. pylori infection. Of these, 27 (32.5%) had bacterial strains resistant to clarithromycin, 3 (3.6%) to levofloxacin, and 4 (4.8%) to both antibiotics.

CONCLUSION

The THD fecal test has high performance for the non-invasive diagnosis of H. pylori infection while additionally enabling the assessment of bacterial antibiotic resistances.

Keywords: Helicobacter pylori, Fecal test, Feces, Stools, 23S rRNA, Molecular analysis, Antibiotic resistance, Diagnostic accuracy

Core tip: Existing studies on molecular tests for Helicobacter pylori (H. pylori) detection in stools show suboptimal quality. The THD fecal test is a newer method to detect bacterial DNA and mutations conferring antibiotic resistance. In this diagnostic test accuracy study involving unselected consecutive participants and blinded outcome assessment, we evaluated the diagnostic accuracy of the THD fecal test for detecting H. pylori, using the 13C-urea breath test as the reference standard. We found that the THD fecal test has high performance for the non-invasive diagnosis of H. pylori infection while additionally enabling the assessment of bacterial antibiotic resistances.