H. pylori’s twisted shape allows it to infect gut

WASHINGTON - The bacterium Helicobacter pylori’s twisted shape like a corkscrew or helix allows it to live in the human stomach and cause ulcers. It has also been linked to gastric cancer.

For the first time, researchers at Fred Hutchinson Cancer Research Centre (FHCRC) proved that at least when it comes to H. pylori’s ability to colonise the stomach, shape indeed matters.

Nina Salama of the FHCRC and colleagues are the first to demonstrate that the bug’s helical shape helps it set up shop in the protective gelatin-like mucus that coats the stomach.

Such bacterial colonisation - present in up to half of the world’s population - causes chronic inflammation that is linked to a variety of stomach disorders, from chronic gastritis and duodenitis to ulcers and cancer.

“By understanding how the bug colonises the stomach, we can think about targeting therapy to prevent infection in the first place,” said Salama, study co-author.

Using a mouse model, the researchers found that lab-engineered mutant strains of H. pylori that are deficient in a group of four proteins fail to twist properly and, consequently, are unable to colonise the stomach.

“Having these mutant strains in hand allowed us to test whether the helical shape is important for H. pylori infection, and it is,” Salama said according to an FHCRC release.

“All of our mutants had trouble colonising the stomach and were out-competed by normal, helical-shaped bugs,” she added.

Mutant forms of H. pylori that lack these proteins are misshapen, ranging from rods to crescents, which hampers their ability to bore through or colonise the stomach lining.

The findings were published in the Friday edition of Cell.