Objectives: A small outbreak of campylobacteriosis involving three cases was investigated in terms of Campylobacter types present in the suspect food (pre-cooked sausages) and clinical samples from the cases.
Method: Foods and faecal samples from people involved in the incident, which occurred in Christchurch, New Zealand, were tested for the presence of Campylobacter and identification of the species made. Isolates were typed by Penner serotyping and macrorestriction analysis using pulsed-field gel electrophoresis (PFGE). Investigations were conducted as to whether the contamination was on the surface or the interior of the sausages.
Results: All isolates from food and faecal samples were identified as C. jejuni and were indistinguishable from one another by the typing methods employed. Only the surfaces of the sausages were contaminated. Three other isolates of an indistinguishable subtype were isolated from campylobacteriosis cases in Christchurch occurring over approximately the same period.
Conclusions and implications: Given the rarity of the subtype isolated from the three family members and the three other cases, it is possible that the outbreak was larger than the initial investigation revealed. It is likely that the sausages were contaminated after they had been cooked by the retailer and were not reheated prior to consumption. This report illustrates the role of cross-contamination in an outbreak with an unusual food vehicle for campylobacteriosis. Physical separation of cooked and raw product is necessary to prevent recurrences of outbreaks similar to the one described here.