Where to Biopsy to Detect Helicobacter pylori and How Many Biopsies Are Needed to Detect Antibiotic Resistance in a Human Stomach.

Maxime Pichon,Marie Aballea,David Tougeron,Jean Pierre Faure,Charlotte Debiais,Sylvain Gautier,Gaëtan Motillon,Christophe Burucoa,Charles Bodet,Cong Tri Tran,Julie Cremniter,Magali Garcia,Philippe Vasseur,Martine Garnier

doi:10.3390/jcm9092812

Abstract

This study aims to determine the gastric distribution, density, and diversity of Helicobacter pylori infection. Subtotal resection of the stomachs of three H. pylori-infected and asymptomatic obese patients were collected after a sleeve gastrectomy. Distribution and density of H. pylori were determined using culture and RT-PCR on multiple gastric sites (88, 176, and 101 biopsies per patient). Diversity of H. pylori strains was studied using antibiotic susceptibility testing, random amplified polymorphism DNA (RAPD) typing and cagA gene detection on single-colony isolates (44, 96, and 49 isolates per patient). H. pylori was detected in nearly all analyzed sites (354/365 biopsies, 97%). Antral density was higher in one patient only. The three stomachs were almost exclusively infected by an antibiotic-susceptible strain. One clarithromycin-resistant isolate in one biopsy was detected in two stomachs (1/44 and 1/49 isolates), while in the third one, eight (8/96 isolates) metronidazole-resistant isolates were detected. DNA typing showed infection with cagA-negative strains for one patient, cagA-positive strains for a second patient and the third patient was infected with two different strains of distinct cagA genotypes. Infection with H. pylori is shown to spread to the whole surface of the stomach, but a possibility of minor sub-population of antibiotic-resistant clones, undetectable in routine practice.

Highlights

Helicobacter pylori (H. pylori) is a Gram-negative bacterium, chronically infecting the gastric mucosa of about half the human population worldwide [1,2]
H. pylori lives either as a planktonic population within the protective mucus layer or are attached to the epithelial surface and persist as microcolonies on the epithelial surface of the gastric glands [4]. This infection, mainly asymptomatic, is responsible for chronic gastritis which may progress to peptic ulcer, adenocarcinoma, and mucosa-associated lymphoid tissue (MALT) lymphoma [1,2,5]
The cag pathogenicity island is responsible for the injection of the CagA bacterial protein into the gastric epithelial cell, enhancing inflammation and carcinogenesis

Summary

Introduction

Helicobacter pylori (H. pylori) is a Gram-negative bacterium, chronically infecting the gastric mucosa of about half the human population worldwide [1,2]. H. pylori lives either as a planktonic population within the protective mucus layer or are attached to the epithelial surface and persist as microcolonies on the epithelial surface of the gastric glands [4] This infection, mainly asymptomatic, is responsible for chronic gastritis which may progress to peptic ulcer, adenocarcinoma, and mucosa-associated lymphoid tissue (MALT) lymphoma [1,2,5]. While earlier studies have shown the antral predominance of bacterial colonization, justifying the recommendation of antral biopsies for bacteriological diagnosis, these studies have only analyzed a small number of biopsies (2 to 12) per patient and have often been based on histological studies (and not on culture or PCR) [13,14,15,16,17,18]. As the distribution of bacteria in the stomach could be heterogeneous, the need for several biopsies is justified, but during routine practice, only one antral and one corpus biopsies are analyzed by the bacteriological laboratory

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