Evidence of Non-sporadic Distribution of Campylobacteriosis Cases in New Zealand

A significant increase in the rate of campylobacteriosis cases in New Zealand was observed during May and June 2006. To characterise the observed increase in reported campylobacteriosis cases 112 Campylobacter isolates [C. jejuni (n = 107), C. coli (n = 5)] were obtained from eight different health districts spanning New Zealand. The isolates were examined using Multi-locus sequence typing (MLST), Pulsed-field gel electrophoresis (PFGE) and Penner Serotyping. Distinct clusters (n = 16) of Campylobacter isolates from multiple health districts, with identical MLST, PFGE (KpnI and SmaI) and Penner serotypes were identified. Two dominant sequence types (ST) ST-474 (n = ) and ST-190 (n = 18) were observed, representing 44.6% of all isolates examined. The distribution of ST-474 and ST-190 was not localised to one health district but were spread over eight health districts, on both the North and South Islands. The spatial pattern of genotypes within the given timeframe, combined with the generalised increase in notifications throughout New Zealand is consistent with a common source epidemic. The epidemic arose from an unidentified source contaminated with the dominant sequence types ST474 and ST190, however the clinical isolates with the dominant sequence types may also represent widely distributed stable clones in New Zealand.