The outbreak was first suspected when a woman
hospitalised with severe gastroenteritis, on 31 July
2003, indicated a particular restaurant as the
possible source of her infection. The Regional
Food Authority (RFA) responsible for the supervision
of the restaurant in question was notified
on the same day and an inspection was carried
out. Samples for bacteriological examination were
taken from the kitchen and the prepared food, but
there were no visible problems and the general
hygiene standards were found to be acceptable.
At the same time, a rise in the number of
S. Typhimurium isolates (antigenic profile
O:4,12; H:i,1.2) with a particular antibiotic resistance
profile (ASSuT, i.e., ampicillin, streptomycin,
sulphamethoxazole and tetracycline resistance)
was noted at the SSI. Patient interviews were
initiated on 7 August, and, after it was found that
four patients became ill after eating at the same
restaurant, the RFA was contacted. The Swedish
Institute for Infectious Disease Control contacted
the RFA independently because of the appearance
of an unusually high number of Swedish patients
infected with S. Typhimurium who reported
visiting Copenhagen. The RFA closed the restaurant
on the morning of 8 August, and no further
cases were reported subsequently. Faecal samples
were collected from the kitchen staff, and
S. Typhimurium was isolated from the sample
of one of the employees, as well as from samples
taken from the buffet served in the restaurant.