Evaluation of Subtyping Methods for the Characterization of Campylobacter Strains from Different Geographical Areas

Abstract

Bacterial foodborne diseases are a common cause of lost productivity for industrially developed nations. In developing nations, these illnesses can be deadly for the young, elderly, and immunocompromised. The ability to accurately characterize the bacteria responsible for foodborne disease is a very important tool for researchers and public health providers. Reported data shows that Campylobacter is one of the most common causes of acute bacterial enteritis globally. The purpose of this study was to evaluate molecular typing techniques used to characterize Campylobacter strains. To this end, 30 C. jejuni strains from Puerto Rico, 56 C. jejuni and C. coli strains from Grenada, and 55 C. jejuni and C. coli strains from the southeastern US were evaluated with pulse-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and flagellin A restriction fragment length polymorphism (flaA-RFLP). FlaA-RFLP was the less expensive method and required less labor than PFGE, but the discriminatory power was low and C. jejuni and C. coli strains grouped together after the analysis. PFGE proved to be the most discriminatory, but most labor intensive, method. PFGE’s limitation as a characterization technique is the failure to restrict some Campylobacter genomes due to DNA methylation or lack of restriction site. MLST, while lacking PFGE’s discriminatory power, can characterize all strains and may provide the best tool for characterization of Campylobacter in temporal, epidemiological studies. This research suggests that a combination of two of the three techniques, depending on the purpose of the characterization, is the best approach when employing molecular typing methods to characterize C. jejuni and C. coli.