Plasmid transfer among members of the Bacillus cereus group associated with food
(2012)
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- Authors
- Supervisors
- Mahillon, Jacques
- Abstract
- (en) The food chain is a favorable environment for contaminants to evolve in complex communities and to acquire new genetic information. Horizontal gene transfer is efficiently achieved by the mechanism of conjugation which is highly dependent on both internal and external factors. This is particularly challenging for members of the Bacillus cereus group whose evolution and virulence have been mainly driven through the dynamics of their plasmid profiles. This study aimed to gather more insights into the effect of food-related conditions, including biofilms, on the potential of both intra- and inter-genera conjugation associated with B. cereus s.l. food contaminants. B. thuringiensis and its model plasmids were chosen as reference system. First, pAW63 plasmid was used to investigate the potential of plasmid transfer among B. thuringiensis through conjugation and mobilization in liquid food matrices, from both animal and vegetal origins, and under salt stress conditions. The data revealed that each of the tested food matrices and stress conditions highly impacts the dynamics of plasmid acquisition and may increase the conjugation potential. Second, pXO16 retromobilization mechanism (plasmid capture) was characterized through the investigation of its transfer kinetics, bringing elements supporting a “two-steps model”. Although pXO16 readily transfers in different liquid food matrices, its conjugation efficiency was found to be marginally affected by the mating substrate. Finally, the study of B. thuringiensis in multi-species biofilms revealed its ability to form highly structured communities with other Gram-positive bacteria. These biofilms greatly increased the potential for plasmid transfer, not only to close relatives, but most notably to other food-borne contaminants that usually share the same niches as B. cereus s.l.
- Affiliations
Citations
Modrie, P. (2012). Plasmid transfer among members of the Bacillus cereus group associated with food. https://hdl.handle.net/2078.5/80713