Evaluation of phenotypic and genotypic methods for subtyping Campylobacterjejuni isolates from humans, poultry, and cattle

Six methods for subtyping of Campylobacter jejuni were compared and evaluat ed with a collection of 90 isolates from poultry, cattle, and sporadic huma n clinical cases as well as from a waterborne outbreak. The applied methods were Penner heat-stable serotyping; automated ribotyping (RiboPrinting); r andom amplified polymorphic DNA typing (RAPD); pulsed-field gel electrophor esis (PFGE); restriction fragment length polymorphisms of the flagellin gen e,flaA (fla-RFLP); and denaturing gradient gel electrophoresis of flaA (fla -DGGE). The methods were evaluated and compared on the basis of their abili ties to identify isolates from one outbreak and discriminate between unrela ted isolates and the agreement between methods in identifying clonal lines. AII methods identified the outbreak strain. For a collection of 80 suppose dly unrelated isolates, RAPD and PFGE were the most discriminatory methods, followed by fla-RFLP and RiboPrinting. fla-DGGE and serotyping were the le ast discriminative. All isolates included in this study were found to be ty peable by each of the methods. Thirteen groups of potentially related isola tes could be identified using a criterion that at least four of the methods agreed on clustering of isolates. None of the subtypes could be related to only one source; rather, these groups represented isolates from different sources. Furthermore, in two cases isolates from cattle and human patients were found to be identical according to all six methods.