Characterization of Strains of Helicobacter pylori: One-Dimensional SDS-PAGE as a Molecular Epidemiologic Tool

One-dimensional linear sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total proteins, coupled with a computerized numerical analysis, was used to distinguish among strains of Helicobacter pylori. One hundred seventy-five clinical strains and five reference strains of H. pylori from humans, four isolates of Helicobacter mustelae from ferrets, and three isolates of H. pylori-like organisms (HPLOs) from miniature swine were examined. Intraspecies and interspecies comparisons were made through a numerical analysis of protein profiles. It was possible to make valid comparisons for strains run on a single gel. However, variations between gels were significant in some cases, and strains from these gels were not compared. Multiple isolates of H. pylori from one patient clustered at greater than 90% similarity. All strains of H. pylori clustered at greater than 60% similarity, whereas H. pylori was clearly distinguishable (less than 40% similarity) from both H. mustelae and HPLOs. An eventual application of this technique will be to determine whether relapse following therapeutic intervention is due to reinfection (from an exogenous source) or to recrudescence.