ABSTRACT
This is the first report of a major foodborne outbreak of enterohaemorrhagic Escherichia coli (EHEC) in Sweden. It occurred among the nursing staff at a children's hospital with approximately 1600 employees. Contaminated lettuce was the most likely source of infection. Nine persons were culture-positive for Escherichia coli (E. coli) O157 and verocytotoxin-positive by PCR and a further two were verocytotoxin-positive by PCR only. All 11 EHEC-positive individuals had attended a party for approximately 250 staff members, which was held at the hospital. In a questionnaire 37 persons stated that they had symptoms consistent with EHEC infection during the weeks after the party. There was no evidence of secondary transmission from staff to patients. The value of PCR as a sensitive and fast method for diagnosis is discussed in this paper. Pulsed-field gel electrophoresis (PFGE) was used to ascertain that staff members were infected by the same clone, and that two patients with E. coli O157 infection were not.
Subject(s)
Disease Outbreaks/statistics & numerical data , Electrophoresis, Gel, Pulsed-Field/methods , Escherichia coli Infections/diagnosis , Escherichia coli Infections/epidemiology , Escherichia coli O157 , Foodborne Diseases/diagnosis , Occupational Diseases/diagnosis , Occupational Diseases/epidemiology , Personnel, Hospital , Polymerase Chain Reaction/methods , DNA, Bacterial/analysis , DNA, Bacterial/genetics , Disease Outbreaks/prevention & control , Electrophoresis, Gel, Pulsed-Field/standards , Epidemiologic Methods , Escherichia coli Infections/microbiology , Escherichia coli Infections/prevention & control , Escherichia coli Infections/transmission , Escherichia coli O157/classification , Escherichia coli O157/genetics , Feces/microbiology , Food Microbiology , Foodborne Diseases/epidemiology , Foodborne Diseases/microbiology , Hospitals, Pediatric , Humans , Infection Control/methods , Lactuca/microbiology , Mass Screening/methods , Occupational Diseases/microbiology , Occupational Diseases/prevention & control , Occupational Health , Personnel, Hospital/statistics & numerical data , Polymerase Chain Reaction/standards , Sensitivity and Specificity , Serotyping , Shiga Toxin 1/genetics , Shiga Toxin 2/genetics , Sweden/epidemiology , Time FactorsABSTRACT
A case-control study was conducted in western Sweden (Alvsborg County). The aim of the study was to identify any special food items or behaviours associated with an increased risk of contracting campylobacter infection. A total of 101 cases and 198 controls were matched for age, sex and district of residence. The following risk factors or risk behaviours were associated with campylobacter infection: drinking unpasteurized milk (OR 3.56, 95% CI 1.46-8.94), eating chicken (OR 2.29, 95% CI 1.29-4.23), or eating pork with bones (chops OR 2.02, 95% CI 1.17-3.64; loin of pork OR 1.83, 95% CI 1.07-3.12), barbecuing (OR 1.98, 95% CI 1.10-4.34), and living or working on a farm (farm OR 3.06, 95% CI 1.58-6.62, hen/chicken-breeder OR 3.32, 95% CI 1.56-6.78), daily contact with chickens or hens (OR 11.83, 95% CI 3.41-62.03).
