title: Bioluminescence based biosensors for quantitative detection of enterococcal peptide-pheromone activity reveal inter-strain telesensing in vivo during polymicrobial systemic infection.
abstract: Enterococcus faecalis is a significant threat in the nosocomial setting due to the emergence of isolates that are multi-antibiotic resistant, refractory to the available therapies and equipped with a variety of pathogenicity determinants. This bacterium uses quorum-sensing systems to regulate its physiological processes, including the expression of virulence traits, to adapt and proliferate within a host. Here, we describe the construction and application of two bioluminescence-based reporter systems for the direct detection of the quorum-sensing regulated expression of (i) the gelatinase biosynthesis-activating pheromone (GBAP) and (ii) the cytolysin small subunit (CylL(S)) in natural samples. The two E. faecalis reporters conditionally expressed bioluminescence in the presence of GBAP and CylL(S) both in the supernatants of liquid cultures and in an agar-overlay assay in as little as three hours, with a high level of sensitivity. Biosensors employed to investigate the interaction between the fsr and cyl systems revealed that fsr impeded CylL(S) activity by 75%. Furthermore, we identified a clinical E. faecalis isolate that acted as a biological cheater, producing cytolysin only upon sensing CylL(S)-producers in its environment. This isolate enhanced its virulence during polymicrobial systemic infection of Galleria mellonella.
authors: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway.
authors: Sabina Leanti
authors: SL
authors: La Rosa
authors: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway.
authors: Margrete
authors: M
authors: Solheim
authors: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway.
authors: Dzung B
authors: DB
authors: Diep
authors: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway.
authors: Ingolf F
authors: IF
authors: Nes
authors: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway.
authors: Dag Anders
authors: DA
authors: Brede
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis / Q000378:metabolism; D015374:Biosensing Techniques / Q000379:methods*; D013293:Enterococcus faecalis / Q000737:chemistry / Q000378:metabolism; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis / Q000378:metabolism; D009036:Moths; D010455:Peptides / Q000032:analysis / Q000378:metabolism; D053038:Quorum Sensing
chemical_list: D001426:Bacterial Proteins; D010455:Peptides