JCM Accepts, published online ahead of print on 17 October 2007

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J. Clin. Microbiol. doi:10.1128/JCM.01631-07
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

Microevolution of Helicobacter pylori type-IV secretion systems in an ulcer disease patient over a 10- year period

Ayesha Alvi, S Manjulata Devi, Irshad Ahmed, M Abid Hussain, Mohammed Rizwan, Hérve Lamouliatte, Francis Mégraud, and Niyaz Ahmed^*

Pathogen Evolution Laboratory, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India; Deccan College of Medical Sciences and Allied Hospitals, Hyderabad, India; Service Hépato-Gastroentérologie, Hôpital Saint André, Bordeaux, France; ISOGEM Working Group on Genetics of Helicobacters, the International Society for Genomic and Evolutionary Microbiology (ISOGEM), Sassari, Italy; INSERM U853, 33076 Bordeaux, France and, Université Victor Segalen Bordeaux 2, Laboratoire de Bactériologie, 33076 Bordeaux, France

^* To whom correspondence should be addressed. Email: niyaz{at}cdfd.org.in.

Helicobacter pylori cagA and vacA genotypes have been used for almost a decade as stable entities to link with the severity of the gastritis and ulcer disease. We describe microevolution of the two genomic islands, cagPAI (40kb) and tfs3 (16kb) from isolates obtained at inclusion (one subclone) and after a 10-year period (two subclones) from a duodenal ulcer patient. Our results indicate microevolution in cagA, cagE and cag7 genes of the cagPAI; and ORFs G, P and L in tfs3, which possibly leads to inactivation or pseudogenization of these genes. Interestingly, no significant reduction in severity of gastroduodenal pathology was found. These results point to an obvious difficulty in correlating the continuously evolving virulence factors such as the cagPAI genes with the disease characteristics that appear to remain stable.