Manipal: Academy of Higher Education researchers in collaboration with their Australian counterparts have sequenced 42 strains of a disease-causing bacterium, Helicobacter pylori, to better understand the genetic factors that play a role in disease development in India. The bacterium stays in the human gut, causes gastritis, peptic ulcers and gastric cancers.

The results of this study are published in journal American Society of Microbiology. The research team includesVignesh Shetty and MamathaBallal from Kasturba Medical College, Manipal, BinitLamichhane, Eng-Guan Chua and Chen-Yen Tay from the Marshall Centre for infectious Diseases Research and Training School of Biomedical Sciences, University of Western Australia.

The findings note that although this infection is spread in all regions of the country, the incidence of infection resulting in gastric cancer is more prevalent in South and North East and is called ‘Indian Enigma’.

High genetic variation in ‘H pylori’ strains from different regions of India is considered one of the major reasons of this Enigma. The bacteria is transmitted through direct contact with saliva, vomit or fecal matter of infected individual.

The KMC, Manipal and Australian scientists have isolated the bacterial strains from the biopsy samples of patients who visited the hospital from the regions of Karnataka and Kerala.

The patients had various kinds of gastritis, peptic ulcers and duodenal ulcers.And the isolated bacteria were grown on nutrient media and then DNA was extracted from the culture mass of bacteria and sequenced.

Further sequence analysis of similar genes from these strains was carried out to understand their relatedness. This analysis showed that South India population harbor ‘H. pylori’ strain from both Asian and European origins.

“Our collection of ‘H. pylori’ strain draft genomes from South India will allow the scientific community to identify whether ‘H. pylori’ genetic factors (if present) play a role in disease development, particularly in that of duodenal ulcer disease, and to compare this role to that in closely relate strains from Northern regions of India,” explained Dr MamathaBallal, author of this study.

The study compared outer membrane proteins, virulence genes harbored by strains from this particular region with strains of East Asian countries where there is a higher rate of gastric cancers.

“It also explored the mechanisms responsible for drug resistance with the identification of mutations in the antimicrobial resistance encoding genes,” Dr Ballal added.