title: Family portrait of Bacillus cereus and Bacillus weihenstephanensis cereulide-producing strains.
abstract: Two thousand Bacillus cereus sensu lato isolates from food and environmental matrices were screened by PCR for the presence of cereulide-producing strains. This survey identified 73 potential emetic strains, most of which originated from non-random food and clinical samplings. None of the 460 Bacillus thuringiensis, Bacillus mycoides and Bacillus pseudomycoides strains were PCR-positive for the cereulide genetic determinants. The chromosomal and extrachromosomal gene pool diversity of a subset of 30 cereulide-producing strains was then assessed using multilocus sequence typing, large plasmid gel electrophoresis and Southern blot hybridization. The strain toxicity on boar sperm and cereulide production were also analysed. The most striking observation was the identification of two distinct clusters of cereulide-producing strains, with members of the second group (cluster II) identified as psychrotolerant B. weihenstephanensis able to grow at 8°C. Moreover, the location of the cereulide genetic determinants was shown to vary depending on the strain, indicating a probable genomic mobility.
authors.affiliation: Laboratory of Food and Environmental Microbiology, Université catholique de Louvain, Croix du Sud, 2/12, B-1348 Louvain-la-Neuve, Belgium. Department of Microbiology, University of Bialystok, 20B Swierkowa Street, PL15-950 Bialystok, Poland. Institute of Public Health, Bacteriology, 14 Rue Juliette Wijtsman, B-1050 Brussels, Belgium. Department of Applied Chemistry and Microbiology, University of Helsinki, P.O. Box 56, Viikinkaari 9, 00014 Helsinki, Finland.
authors.forename: Florence M
authors.initials: FM
authors.lastname: Hoton
authors.forename: Nadine
authors.initials: N
authors.lastname: Fornelos
authors.forename: Elise
authors.initials: E
authors.lastname: N'guessan
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Hu
authors.forename: Izabela
authors.initials: I
authors.lastname: Swiecicka
authors.forename: Katelijne
authors.initials: K
authors.lastname: Dierick
authors.forename: Elina
authors.initials: E
authors.lastname: Jääskeläinen
authors.forename: Mirja
authors.initials: M
authors.lastname: Salkinoja-Salonen
authors.forename: Jacques
authors.initials: J
authors.lastname: Mahillon