Molecular methods for typing of Helicobacter pylori and their applications

Microbial typing is a useful tool in clinical epidemiology for defining the source and route of infection, for studying the persistence and reinfectio n rates, clonal selection in the host and bacterial evolution. Phenotypic m ethods such as biotyping, serotyping and hemagglutinin typing have little d iscriminatory power compared to genotypic methods concerning the typing of Helicobacter pylori. Therefore great efforts have been made to establish us eful molecular typing methods. In this context, the most frequently used ge notypic methods are described based on our own experience and the literatur e: (1) restriction endonuclease analysis, (2) endonuclease analysis using p ulsed-field gel electrophoresis, (3) ribotyping, (4) polymerase chain react ion (using either random primers or repetitive DNA sequence primers), and ( 5) polymerase chain reaction-restriction fragment length polymorphism analy sis of e.g. the urease genes. Furthermore, reproducibility, discriminatory power, ease of performance and interpretation, cost and toxic procedures of each method are assessed. To date no direct comparison of all the molecula r typing methods described has been performed in the same study with the sa me H. pylori strains. However, PCR analysis of the urease gene directly on suspensions of H. pylori or gastric biopsy material seems to be useful for routine use and applicable in specific epidemiological situations. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Sc ience B.V. All rights reserved.