Role of Putative Pathogenicity Island in Campylobacter jejuni Virulence

Incidence of campylobacteriosis in man has risen dramatically in the past 10 years and passed salmonellosis as the number one disease acquired by consuming contaminated food products. It is estimated that Campylobacter jejuni causes 3 million cases per year; with a cost due to treatment and loss of productivity greater than 1 billion dollars. Clearly; understanding mechanisms by which this major pathogen causes disease is invaluable. Nevertheless; few factors associated with C. jejuni virulence have been identified. Progress in this important research area has been hampered by the lack of genetic tools to examine or identify virulence factors. To date; roughly ninety C. jejuni genes have been characterized; only six of which are related to virulence. Recently we have isolated an iron uptake system encoded within a putative pathogenicity island from virulent C. jejuni. Genes within this island may be influential in definingthe pathogenicity of the agent that will lead to control measures for decreasing the incidence of campylobacteriosis. The long range goal of the proposed research is to evaluate genes contained within a putative pathogenicity island in c. jejuni for their role in virulence. Sequence analysis reveals an area that for encodes two disparate physiologic function; an iron uptake system; and a cell wall biosynthetic pathway; suggesting that maintenance of this unique island may not be due to environmental iron limitations alone. The island may encode other functions and comprise not only an iron uptake island but a pathogenicity island. Consistent with these observations we hypothesize that this locus comprises a pathogenicity island which contributes to C. jejuni virulence.