Epidemiology and Infection

Gastroenteritis

Large outbreak of Salmonella Enteritidis PT8 in Portsmouth, UK, associated with a restaurant

E. SEVERIa1 c1, L. BOOTHa2, S. JOHNSONa1, P. CLEARYa3, M. RIMINGTONa4, D. SAUNDERSa5, P. COCKCROFTa6 and C. IHEKWEAZUa1

a1 South East Regional Epidemiology Unit, Health Protection Agency, London, UK

a2 Hampshire and Isle of Wight HPU, Health Protection Agency, Whiteley, UK

a3 North West Regional Epidemiology Unit, Health Protection Agency, Liverpool, UK

a4 Environment and Public Protection Service, Portsmouth City Unitary Authority, UK

a5 Directorate of Public Health, Portsmouth City Teaching Primary Care Trust, UK

a6 Department of Clinical Microbiology, Portsmouth Hospitals NHS Trust, UK

SUMMARY

Seventy-five individuals with Salmonella infection were identified in the Portsmouth area during August and September 2009, predominantly Salmonella Enteritidis phage type 8. Five patients were admitted to hospital. A case-case comparison study showed that a local restaurant was the most likely source of the infection with a risk of illness among its customers 25-fold higher than that of those who did not attend the restaurant. A case-control study conducted to investigate specific risk factors for infection at the restaurant showed that eating salad was associated with a threefold increase in probability of illness. Changing from using ready washed lettuces to lettuces requiring washing and not adhering strictly to the 48 hours exclusion policy for food handlers with diarrhoea were likely to have contributed to the initiation and propagation of this outbreak. Possibilities for cross-contamination and environmental contamination were identified in the restaurant.

(Accepted November 17 2011)

(Online publication December 14 2011)

Correspondence:

c1 Author for correspondence: Mr E. Severi, Health Protection Agency, 151 Buckingham Palace Road, London SW1W 9SZ, UK. (Email: ettore.severi@hpa.org.uk)

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