Salmonella typhimurium and norovirus food-borne outbreak in a restaurant

Abstract number: P1639

Arias Varela C., Sala Farré M.R., Recasens Recasens A., Bartolomé R.

Objectives:Salmonella Typhimurium (ST) and norovirus (NV) are the leading cause of food borne outbreaks of gastroenteritis in Catalonia; however outbreaks caused with mixed viral-bacterial gastroenteritis are unusual. This report describes the first food borne detected in Catalonia with ST and NV together implicated. Two groups of costumers ate on the same restaurant in a two consecutive days before became ill.

Methods: A study of historic cohorts was performed. The case was defined by the presence of diarrhoea and vomiting. Data were gathered on age, sex, foods consumed and clinical symptoms. Attack rates and relative risk were calculated. Food and stool samples from cases and food handlers were analysed for bacterial and viruses (test RT-PCR). Bacterial isolated strains were studied using pulsed-field gel electrophoresis (PFGE). Food handlers were asked about food procedures and a inspection of the restaurant was undertaken.

Results: The outbreak occurred from August 7 to 9, 2005 involving 20 cases (65% total attack rate). Clinical symptoms included general malaise (95%), diarrhoea 85, headache (85%), abdominal pain (80%), muscular pain (80%), fever (75%), nausea (33%) and vomiting (25%). Median duration of the disease was 4 days.

There were a significant association with the disease and eating mixed vegetables (RR = 4.95; CI 95%, 1.40–17.50) and fish salad (RR = 2.25; CI 95%, 1.25–4.05). Stool samples of 4 cases were ST positives ST, one case for NV and 5 cases for ST and NV. Stool samples from food handler were ST positives (1) and both ST and NV (2). Furthermore ST was also isolated in the food samples. The ST strains from 9 confirmed cases, from food handlers and food had identical PFGE patterns. Restaurant inspection detected that cross contamination of food were possible.

Conclusion: This food borne epidemic outbreak was caused by ST and NV. Epidemiological analysis shows that mixed vegetables and fish salad were the main foods implicated. Microbiological information is consistent with the outbreak could occurred as a result of food contamination by a food handler. ST infection could be also as a result of cross contamination and mishandling of food.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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