Background: From June 13-16, 2022, in Kazakhstan, 50 people were hospitalized with diarrhea; all reported having attended a wedding or eaten food from the restaurant where the wedding took place. We conducted an outbreak investigation on June 17-26 to identify the source and prevent further cases.

Methods: We used a retrospective cohort study of people who had either attended the wedding or eaten food served at the wedding (N = 138). A probable case was defined as people who were at the wedding on July 12th or had consumed food from the restaurant from that day with diarrhea, vomiting, and/or fever >38°C. Consenting guests answered questions about symptoms and consumption of foods provided at the restaurant. Patient stool and gastric lavage samples and food and environmental samples were tested. We used log-binomial logistic regression to determine associations with case status

Results: We identified 74 probable cases (50 had been hospitalized); 66 consented to participate. Most common symptoms included diarrhea (92%), abdominal pain (91%), and fever (89%). Symptoms began 6 hours to four days after the event. Most case participants (43%) were <19 years old and 64% had eaten event leftovers (attack rate [AR] was 74% and 81% in these groups respectively). Cake was eaten by 89% of cases vs. 13% of non-cases (AR: 87%); adjusted relative risk was 5.4 (95% confidence interval: 3.1-9.3). Salmonella enteriditis were isolated from all stool samples (49 of 49) and 2 of 2 cake samples. Staphylococcus aureus (103 cfu/ml) were detected in 35 of 38 gastric samples.

Conclusions: Two pathogens were identified, but patient symptoms were more consistent with Salmonella enteriditis, which was recovered from both patients’ stool and cake samples. Leftover food was discarded, and the environment sanitized. Recommendations were made to the restaurant to ensure compliance with food safety measures. The public was informed about food safety.