Population Biology ofCampylobacter jejuniand Related Organisms

This chapter explores the contribution that population studies have made to one's understanding of the biology of the Campylobacter, and the authors argue that such studies have a central role to play in understanding the epidemiology and pathogenesis of this important group of gram-negative bacteria. Campylobacter jejuni and Campylobacter coli cause the majority of human cases of Campylobacter-associated gastroenteritis; these two organisms are associated with approximately 90 and 10% of cases, respectively. This chapter discusses variation within the genus Campylobacter. Although human infection is one of the most important practical applications of studies of Campylobacter populations, in terms of Campylobacter population dynamics and evolution, infection is probably irrelevant. Understanding the population biology of Campylobacter is, however, crucial in understanding the transmission to humans and developing means for its control. It is instructive to reflect that the first study of C. jejuni and C. coli population structure by multilocus enzyme electrophoresis provided many insights that have proved to be correct and that have been extended and deepened by multilocus sequence typing (MLST) studies. Ongoing nucleotide sequence-based studies involving large numbers of isolates and improved genealogical analysis tools provide the highly attractive prospect that well within the next 10 years, the population biology of these organisms, at least insofar as it relates to human infection, will be effectively resolved.