SMI is a government expert authority with a mission to monitor the epidemiology of infectious disease among Swedish citizens and promote control and prevention of these diseases. SMI is also a leading research institute. The vicinity to the Karolinska Institute as well as grants from national and international organisations and the EU have made it possible for SMI to recruit many of the most prominent scientists. One of the most modern microbiological laboratories for diagnostics and research is located at SMI and constitutes an important resource in national disease control and prevention.

We will develop a method for genotyping of archived, formalin-fixed microbial and host cell material. In order to enrich the bacterial material, we will try to combine this technique with laser capture micro-dissection. This will potentially open up for very targeted analyses, for instance of H. pylori that are attached to the mucosal cells, or microorganisms residing in the neck region of the gastric glands, near the progeny cells, where carcinogenic mutations will have the greatest chance to accumulate. Furthermore, we are studying intra-strain variations (Lewis antigen expression) of single cell isolates of H. pylori from biopsies taken from individuals who develop pre-cancer lesions in a random population-based study with a four-year interval.

Hansson LR, Engstrand L, Nyren O, Lindgren A. Prevalence of Helicobacter pylori infection in subtypes of gastric cancer. Gastroenterology 1995;109(3):885-8. Ekstrom AM, Held M, Hansson LE, Engstrand L, Nyren O. Helicobacter pylori in Gastric Cancer Established by CagA Immunoblot as a Marker of Past Infection. Gastroenterology 2001;121(4):784-91. Held M, Engstrand L, Hansson LE, Bergstrom R, Wadstrom T, Nyren O. Is the association between Helicobacter pylori and gastric cancer confined to CagA-positive strains? Helicobacter 2004;9(3):271-7. Lundin A, Björkholm B, Kupershmidt I, Unemoo M, Nilsson P, Andersson DI, Engstrand L. Slow genetic divergence of Helicobacter pylori during long-term colonization. Infect Immun, 2005; 73:4818-22 Nilsson C, Skoglund A, Moran AP, Annuk H, Engstrand L Normark S. An enzymatic molecular ruler modulates Lewis antigen glycosylation of Helicobacter pylori lipopolysaccharide during persistent infection. Proc Natl Acad Sci 2006 ;109:2863-2868 Jung D, Kling-Bäckhed H, Giannakis M, Xu J, Fulton R, Fulton L, Cordum H, Wang C, Elliot G, Edwards J, Mardis E.R, Engstrand L, Gordon J.I. The complete genome sequence of a Helicobacter pylori isolate from a patient with chronic atrophic gastritis: characterization of genome evolution during disease progression. Proc Natl Acad Sci 2006: 103(26):9999-10004