Does age acquired immunity confer selective protection to common serotypes of Campylobacter jejuni?

BACKGROUND: Campylobacter infection is a major cause of bacterial gastrointestinal disease. Exposure to Campylobacter is known to produce an immune response in humans that can prevent future symptomatic infections. Further, studies of the general population have shown that seroprevalence to Campylobacter increases with age. METHODS: A large collection of serotyped Campylobacter isolates, obtained from human clinical faecal samples, were analysed by comparing the ratio of uncommon to common serotypes by different age groups, using χ(2 )tests. RESULTS: We have identified that older age groups, as well as having generally lower incidence, are significantly less likely to be infected by the more common serotypes. CONCLUSION: These results are indicative of acquired immunity, however, further studies are needed to rule out the confounding effects of the variations in exposure pathways experienced by different age groups.