Barbecued chicken causing a multi-state outbreak of Campylobacter jejuni enteritis

Background: Although the microbiological safety of food has improved, food-borne disease remains a significant cause of morbidity and mortality in Europe. Patients and Methods: We investigated an outbreak of Campylobacter jejuni enteritis attributed to chicken meat, affecting five out of six people attending a private barbecue party in Germany. Patients fell ill in Germany, in Liechtenstein and in Austria. 80% of the cases had been exposed to barbecued chicken; the case that denied having eaten chicken was the party host, who also handled all the food. Three of four patients submitting stool specimens had culture-confirmed C jejuni infection. Results: The chicken meat was purchased in the Tyrol (Austria) and originated from a flock of 55,600 chickens raised in Carinthia (Austria). Caecal swabs were obtained 7 weeks later from 22 chickens at the incriminated farm: 18 of the 22 samples yielded C. jejuni. The same day, six carcasses out of 22,000 slaughtered animals from the incriminated farm were tested and all six food samples yielded C. jejuni. Outbreak-associated human isolates yielded pulsed-field gel electrophoresis patterns indistinguishable from each other and from the meat isolates, but different from four human control strains and from 13 of 16 isolates from caecal swabs. Conclusion: Our data show that the outbreak clone had been colonizing the slaughterhouse and was cross-contaminating chickens there. The geographic mobility of people and food necessitates proper epidemiologic investigations to avoid overestimation of the proportion of sporadic occurrence of campylobacteriosis.