PCR assay targeting virulence genes of Helicobacter pylori isolated from drinking water and clinical samples in Lahore metropolitan, Pakistan

Abstract

Helicobacter pylorus is considered for chronic gastritis, gastric ulcers and adenocarcinoma and its high infection rate is observed in overcrowded and lower socioeconomic groups in developing countries. This study was designed to identify the role of drinking water in the transmission and prevalence of H. pylori (HP). Selective HP medium was developed for enrichment and presumptive identification of H. pylori by urease, catalase and species specific 16S rRNA tests. The virulence genes (vacA 's' and 'm' regions and cagA) of H. pylori in 90 out of 225 H. pylori positive drinking water samples were present (40%). Ten out of 18 biopsies (55.55%) and 15 out of 50 vomiting fluids of gastric disease patients (30%) were also positive for virulence genes. Anti-H. pylori antibodies were also detected in 31 out of 50 patients' sera. The presence of virulence genes was also directly confirmed by hybridization studies using non-radioactive DNA probes of 16S rRNA, vacA and cagA genes. The presence of H. pylori in water is due to poor sanitary conditions, improper waste disposal and lack of public health education. PCR-based analysis and colony hybridization can be used for detection of H. pylori in clinical and environmental samples.

Genotyping of vacA alleles of <i>Helicobacter pylori</i> strains recovered from some Iranian food items

“…Roles of contaminated water and even drinking water in transmission of H. pylori have been confirmed previously [17][18][19][20]. Probably, the water sources used for production, washing and processing of these foods samples were contaminated.…”

“…High amount of Aw in meat base food samples, optimum pH and salt levels, presence of appropriate levels of amino acids including arginine, histidine, isoleucine, leucine, methionine, phenylalanine, alanine, valine, proline, serine, and tryptophan favors the for growth of H. pylori [12], this is in addition to unsanitary conditions in their preparation and cross contamination of these foods due to handling by factory and food units staffs. High prevalence of H. pylori in foods with animal origin has been reported previously [5,9,15,17,18,20].…”

Presence of Helicobacter pylori in drinking water of Karachi, Pakistan

“…The presence of H. pylori was observed in 4% of the treated water samples from Karachi. A recent study reports the presence of H. pylori in 40% of water samples collected from Lahore, a city located in a different province of Pakistan [16]. The sharp contrast in the positivity rates of these two cities is surprising and raises serious concerns about the quality of water and the water distribution system.…”

Helicobacter pylori infection in pregnant women in four districts of Uganda: role of geographic location, education and water sources

“…Fujimura et al [45] demonstrated that river water in the natural environment could be a risk factor for H. pylori transmission. H. pylori has previously been detected in drinking water [46, 47]. The presence of H. pylori in water supplies might be the result of contamination from human sewage [48–51].…”