Faculty of Food Technology and Biotechnology, University of Zagreb
Abstract
Poultry meat samples from Slovenian retail market were examined for the presence of thermotolerant campylobacters. The isolates were identified by phenotypic and genotypic methods. ISO 10272 recommendations were followed for phenotypic identification. Different PCR assays, targeting species specific DNA regions in C. jejuni and C. coli, were checked for their applicability in identification. High degree of tested samples was positive (27/33), with significant proportion of C. coli (32 %) among identified strains. High percentage of C. jejuni strains (54 %) were hippurate negative. Phenotypic identification was therefore found to be inconvenient because of the presence of the strains with atypical phenotype and possible misinterpretation of test results. Multiplex PCR, targeting hippuricase gene in C. jejuni and species specific region in C. coli, was found to be an efficient method that allowed fast, simple and accurate identification of C. jejuni and C. coli. FlaA PCR is a reliable method to identify the group C. jejuni/C. coli, but it does not differentiate between the two species. CdtB PCR is inconvenient because of many false negative and some false positive results.Ispitana je prisutnost termotolerantnih bakterija roda Campylobacter u uzorcima piletine sa slovenskog tržišta. Izolirani su sojevi identificirani fenotipskim i genotipskim postupcima. Fenotipska je identifikacija provedena klasičnim postupkom ISO 10272. Da bi se identificirali određeni sojevi, ispitana je primjenjivost različitih PCR postupaka, korištenjem specifičnih DNA regija za vrste C. jejuni i C. coli. Veliki broj ispitivanih uzoraka bio je pozitivan (27/33), sa značajnim udjelom C. coli u tim dvama identificiranim sojevima (32 %). Veliki udjel sojeva C. jejuni (54 %) bio je hipurat negativan. Fenotipska je identifikacija stoga neprikladan postupak zbog prisutnosti sojeva s atipičnim fenotipom, a i zbog mogućnosti pogrešne interpretacije rezultata testova. Multipleks PCR-postupak, koristeći hipurikazni gen u C. jejuni i u specifičnoj regiji za vrstu C. coli, pokazao se uspješnim jer omogućava brzu, jednostavnu i točnu identifikaciju C. jejuni i C. coli. Postupak PCR s lokusom flagelarnoga gena (flaA PCR) pouzdan je postupak za identifikaciju C. jejuni/C. coli, ali se njime ne mogu razlikovati te dvije vrste. Postupak PCR s lokusom gena citoletalnog toksina (cdtB PCR) nije prikladan jer daje puno lažno negativnih, a i nešto lažno pozitivnih rezultata
