title: Elucidation of enterotoxigenic Bacillus cereus outbreaks in Austria by complementary epidemiological and microbiological investigations, 2013.
abstract: Identifying Bacillus cereus as the causative agent of a foodborne outbreak still poses a challenge. We report on the epidemiological and microbiological investigation of three outbreaks of food poisoning (A, B, and C) in Austria in 2013. A total of 44% among 32 hotel guests (A), 22% among 63 employees (B) and 29% among 362 residents of a rehab clinic (C) fell sick immediately after meal consumption. B. cereus isolated from left overs or retained samples from related foods were characterized by toxin gene profiling, and molecular typing using panC sequencing and M13-PCR typing (in outbreak A and C). We identified two B. cereus strains in outbreak A, and six B. cereus strains, each in outbreak B and C; we also found Staphylococcus aureus and staphylococcal enterotoxins in outbreak A. The panC sequence based phylogenetic affiliation of the B. cereus strains, together with findings of the retrospective cohort analyses, helped determining their etiological role. Consumption of a mashed potatoes dish in outbreak A (RR: ∞), a pancake strips soup in outbreak B (RR 13.0; 95% CI 1.8-93.0) and for outbreak C of a fruit salad (RR 1.50; 95% CI 1.09-2.00), deer ragout (RR: 1.99; 95% CI 1.23-3.22) and a cranberry/pear (RR 2.46; 95% CI 1.50-4.03)were associated with increased risk of falling sick. An enterotoxigenic strain affiliated to the phylogenetic group with the highest risk of food poisoning was isolated from the crème spinach and the strawberry buttermilk, and also from the stool samples of the one B. cereus positive outbreak case-patient, who ate both. Our investigation of three food poisoning outbreaks illustrates the added value of a combined approach by using epidemiological, microbiological and genotyping methods in identifying the likely outbreak sources and the etiological B. cereus strains.
authors.affiliation: Austrian Agency for Health and Food Safety, Währinger Straße 25a, 1090 Vienna, Austria.
authors.forename: Daniela
authors.initials: D
authors.lastname: Schmid
authors.affiliation: Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.
authors.forename: Corinna
authors.initials: C
authors.lastname: Rademacher
authors.affiliation: Austrian Agency for Health and Food Safety, Währinger Straße 25a, 1090 Vienna, Austria.
authors.forename: Elisabeth Eva
authors.initials: EE
authors.lastname: Kanitz
authors.affiliation: Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.
authors.forename: Elrike
authors.initials: E
authors.lastname: Frenzel
authors.affiliation: Austrian Agency for Health and Food Safety, Währinger Straße 25a, 1090 Vienna, Austria.
authors.forename: Erica
authors.initials: E
authors.lastname: Simons
authors.affiliation: Austrian Agency for Health and Food Safety, Währinger Straße 25a, 1090 Vienna, Austria.
authors.forename: Franz
authors.initials: F
authors.lastname: Allerberger
authors.affiliation: Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.
authors.forename: Monika
authors.initials: M
authors.lastname: Ehling-Schulz
mesh_terms: D001317:Austria / Q000453:epidemiology; D001409:Bacillus cereus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D001483:Base Sequence; D004196:Disease Outbreaks; D004768:Enterotoxins / Q000235:genetics; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000382:microbiology*; D005638:Fruit / Q000382:microbiology; D005838:Genotype; D006801:Humans; D058889:Molecular Typing; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012189:Retrospective Studies; D017422:Sequence Analysis, DNA; D011198:Solanum tuberosum / Q000382:microbiology; D018724:Spinacia oleracea / Q000382:microbiology; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D004768:Enterotoxins
keywords: Cohort study; Food poisoning; Molecular typing; Risk ratio; panC sequencing