First general outbreak of Verocytotoxin-producing Escherichia coli O157 in Denmark.
This report describes the first general outbreak of verocytotoxin-producing E. coli (VTEC) in Denmark. Twenty five patients, 18 children and seven adults, with culture-confirmed VTEC O157:H- infection and indistinguishable pulsed-field gel electrophoresis DNA profiles, were identified during a six month period from September 2003 to March 2004. The outbreak strain possessed the virulence genes: eae, vtx1 and vtx2c. All patients but one presented with diarrhoea; none developed haemolytic uraemic syndrome. The outbreak was restricted to Copenhagen and surrounding areas. A case-control study including 11 cases and 55 matched controls revealed an association between VTEC O157:H- infection and shopping in a specific supermarket chain in Copenhagen and surrounding area, matched odds ratio (OR): 8.7 (95% confidence interval (CI): 1.1-71). After exclusion of three assumed secondary cases, only consumption of a particular kind of organic milk from a small dairy was associated with disease OR: 8.7 (95% CI 1.6-48). Environmental and microbiological investigations at the suspected dairy did not confirm the presence of the outbreak strain, but the outbreak stopped once the dairy was closed and thoroughly cleaned.
Jensen
C
C
Department of Bacteriology, Mycology and Parasitology, Statens Serum Institut, Copenhagen, Denmark.
Ethelberg
S
S
Gervelmeyer
A
A
Nielsen
E M
EM
Olsen
K E P
KE
Mølbak
K
K
D000818:Animals; D016022:Case-Control Studies; D003612:Dairying; D003718:Denmark / Q000453:epidemiology; D004196:Disease Outbreaks; D004783:Environmental Microbiology; D004927:Escherichia coli Infections / Q000453:epidemiology*; D019453:Escherichia coli O157; D006801:Humans; D008892:Milk / Q000382:microbiology; D011159:Population Surveillance