Introduction: In May of 2012, we investigated a food-borne Clostridium perfringens outbreak in Slovenia involving a single kitchen and five venues, with 477 exposed persons.
Methods: In order to identify the causative agent, vehicle of infection and source of contamination, we conducted microbiological and environmental investigations and an analytical cohort study (n = 138).
Results: The case definition in the outbreak was met by 104 persons. Predominant symptoms were diarrhoea, nausea and abdominal cramps. Median incubation time and duration of illness were 12 and 22.5 hours respectively. Stool samples were collected from 18 persons and in 13 C. perfringens spores were present; enterotoxin was detected in 9 persons. PCR and PFGE analysis of isolates from a cook with earlier onset time, who did not consume the implicated food, and cases from four venues showed the same strain of C. perfringens type A (with cpe-gene), indistinguishable by PFGE analysis. No food samples could be obtained. An analytical study showed that one food item (French salad) was the most likely vehicle of infection (RR: 6.35; 95% CI: 1.62-24.90).
Conclusions: This was the largest C. perfringens outbreak in Slovenia to date. Proper analytical study in combination with detailed laboratory investigation with genotypisation enabled us to identify a causative agent, vehicle of infection and possible source of contamination. Fast response and interdisciplinary collaboration led to timely implementation of control measures. These have led to the kitchen acquiring new equipment and improving staff knowledge of risks and processes, thus reducing the likelihood of future reoccurrences.
Uvod: V maju 2012 smo preiskovali izbruh okužb s Clostridium perfringens, prenesenih s hrano, v katerega so bile vpletene ena kuhinja in pet lokaciji s 477 izpostavljenimi osebami.
Metode: Da bi ugotovili povzročitelja, pot prenosa in vir kontaminacije, smo izvedli laboratorijsko in okoljsko preiskavo ter analitično kohortno raziskavo (n = 138).
Rezultati: Definiciji primera v izbruhu so ustrezale 104 osebe. Prevladujoči simptomi so bili: driska, slabost in trebušni krči. Mediana časa inkubacije in trajanja bolezni je bila 12 ur in 22,5 ure. Vzorci blata so bili odvzeti 18 osebam; pri 13 so bile prisotne spore C. perfringens, enterotoksin je bil zaznan pri 9 osebah. PCR- in PFGE-analiza izolatov kuharja z zgodnejšim časom pojava obolenja, ki ni užival impliciranih živil, in primerov s štirih lokacij sta pokazali enak sev C. perfringens tipa A (s cpe genom), ki se ni razlikoval pri analizi PFGE. Vzorcev živil ni bilo mogoče pridobiti. Analitična študija je pokazala, da je bila najverjetnejša pot prenosa okužbe eno izmed živil (francoska solata) (RT: 6,35; 95% IZ: 1,62–24,90).
Zaključek: To je bil največji izbruh s C. perfringens v Sloveniji do zdaj. Ustrezna analitična raziskava v kombinaciji s podrobno laboratorijsko preiskavo z genotipizacijo nam je omogočila identifikacijo povzročitelja, pot prenosa okužbe in mogoč vir kontaminacije. Hiter odziv in interdisciplinarno sodelovanje je pripeljalo do pravočasne implementacije nadzornih ukrepov. Ti so privedli do nabave nove opreme v kuhinji, izboljšanja znanja osebja o tveganjih in procesih ter s tem zmanjšali verjetnost za ponovitve v prihodnje.
Keywords: Clostridium perfringens; cohort studies; epidemiology; infectious diseases outbreaks.