title: Diversity of pulsed-field gel electrophoresis patterns of cereulide-producing isolates of Bacillus cereus and Bacillus weihenstephanensis.
abstract: Bacillus cereus is an important foodborne pathogen causing diarrhoea, emesis and in, rare cases, lethal poisonings. The emetic syndrome is caused by cereulide, a heat-stable toxin. Originally considered as a rather homogenous group, the emetic strains have since been shown to display some diversity, including the existence of two clusters of mesophilic B. cereus and psychrotolerant B. weihenstephanensis. Using pulsed-field gel electrophoresis (PFGE) analysis, this research aimed to better understand the diversity and spatio-temporal occurrence of emetic strains originating from environmental or food niches vs. those isolated from foodborne cases. The diversity was evaluated using a set of 52 B. cereus and B. weihenstephanensis strains isolated between 2000 and 2011 in ten countries. PFGE analysis could discriminate 17 distinct profiles (pulsotypes). The most striking observations were as follows: (1) more than one emetic pulsotype can be observed in a single outbreak; (2) the number of distinct isolates involved in emetic intoxications is limited, and these potentially clonal strains frequently occurred in successive and independent food poisoning cases; (3) isolates from different countries displayed identical profiles; and (4) the cereulide-producing psychrotolerant B. weihenstephanensis were, so far, only isolated from environmental niches.
authors.affiliation: Laboratory of Food and Environmental Microbiology, Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Virginie
authors.initials: V
authors.lastname: Castiaux
authors.forename: Elise
authors.initials: E
authors.lastname: N'guessan
authors.forename: Izabela
authors.initials: I
authors.lastname: Swiecicka
authors.forename: Laurence
authors.initials: L
authors.lastname: Delbrassinne
authors.forename: Katelijne
authors.initials: K
authors.lastname: Dierick
authors.forename: Jacques
authors.initials: J
authors.lastname: Mahillon
mesh_terms: D001407:Bacillus / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D001409:Bacillus cereus / Q000145:classification / Q000235:genetics / Q000378:metabolism; D015373:Bacterial Typing Techniques; D047630:Depsipeptides / Q000378:metabolism*; D016521:Electrophoresis, Gel, Pulsed-Field; D004639:Emetics; D004783:Environmental Microbiology; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000382:microbiology; D014644:Genetic Variation; D016680:Genome, Bacterial / Q000235:genetics*; D006801:Humans; D062211:Spatio-Temporal Analysis
chemical_list: D047630:Depsipeptides; D004639:Emetics; C089294:cereulide
keywords: Bacillus cereus sensu lato; emetic strains