Laursen, Martin Frederik2; Bahl, Martin Iain2; Licht, Tine Rask4; Gram, Lone5; Knudsen, Gitte Maegaard3
1 Department of Systems Biology, Technical University of Denmark2 National Food Institute, Technical University of Denmark3 Bacterial Ecophysiology and Biotechnology, Department of Systems Biology, Technical University of Denmark4 Copenhagen Center for Health Technology, Center, Technical University of Denmark5 Bacterial Ecophysiology and Biotechnology, Department of Biotechnology and Biomedicine, Technical University of Denmark
Listeria monocytogenes can cause the potentially fatal food-borne disease listeriosis, and the use of bacteriocin-producing lactic acid bacteria to control L. monocytogenes holds great promise. However, development of bacteriocin resistance is a potential challenge and the purpose of this study was to determine if exposure to sublethal concentrations of pediocin-containing Lactobacillus plantarum WHE 92 supernatant could prime L. monocytogenes for resistance. By transcriptomic analysis, we found two, 55 and 539 genes differentially expressed after 10, 60 and 180 min of exposure to L. plantarum WHE 92 supernatant as compared to control exposures. We observed temporal expression changes in genes regulated by the two component system LisRK and the alternative sigma factors SigB and SigL. Additionally, several genes involved in bacteriocin resistance were induced. ΔlisR, ΔsigB and ΔsigL mutants were all more resistant than wild types to L. plantarum WHE 92 supernatant. LisRK, SigB and SigL regulation and genes associated with resistance are involved in the temporal adaptive response to pediocin and all three regulatory systems affect pediocin resistance. Thus, a single exposure to a sublethal pediocin concentration initiates a response pointing to resistance and indicates that further research exploring the link between adaptive responses and resistance is needed.
Environmental Microbiology, 2015, Vol 17, Issue 4, p. 1134-1151