title: Using an insect model to assess correlation between temperature and virulence in Bacillus weihenstephanensis and Bacillus cereus.
abstract: The closely related bacterial species Bacillus cereus and Bacillus weihenstephanensis are adapted to the mesophilic and the psychrotrophic temperature range, respectively. While B. cereus strains are associated with foodborne diseases, B. weihenstephanensis strains are so far not, although similar virulence genes are found in both species. Our investigations show that both species were virulent in the insect model, Galleria mellonella, following infection via oral and haemocoel routes. However, virulence of B. weihenstephanensis was much higher at 15°C than at 37°C. Furthermore, a temperature-dependent difference between the species was seen in a cell culture cytotoxicity assay. In summary, our results demonstrate for the first time virulence of B. weihenstephanensis strains in an in vivo model. In addition, we found that G. mellonella is a useful model for studies of the psychrotolerant species of the B. cereus group, suggesting that insects might be an ecological growth niche for several members of this bacterial group.
authors.affiliation: Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Section for Food Safety, Oslo, Norway. lotte.s.arnesen@nvh.no
authors.forename: Lotte
authors.initials: L
authors.lastname: Stenfors Arnesen
authors.forename: Per Einar
authors.initials: PE
authors.lastname: Granum
authors.forename: Christophe
authors.initials: C
authors.lastname: Buisson
authors.forename: Jon
authors.initials: J
authors.lastname: Bohlin
authors.forename: Christina
authors.initials: C
authors.lastname: Nielsen-LeRoux
mesh_terms: D000818:Animals; D001407:Bacillus / Q000472:pathogenicity*; D001409:Bacillus cereus / Q000472:pathogenicity*; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology; D002522:Chlorocebus aethiops; D007313:Insecta / Q000382:microbiology*; D013696:Temperature; D014709:Vero Cells; D014774:Virulence / Q000235:genetics / Q000502:physiology
chemical_list: D001426:Bacterial Proteins