Abstract
Infections by Burkholderia cenocepacia lead to life-threatening disease in immunocompromised individuals, including those living with cystic fibrosis (CF). While genetic variation in various B. cenocepacia strains has been reported, it remains unclear how the chemical environment of CF lung influences the production of small molecule virulence factors by these strains. Here we compare metabolomes of three clinical B. cenocepacia strains in synthetic CF sputum medium (SCFM2) and in a routine laboratory medium (LB), in the presence and absence of the antibiotic trimethoprim. Using a mass spectrometry-based untargeted metabolomics approach, we identify several compound classes which are differentially produced in SCFM2 compared to LB media, including siderophores, antimicrobials, quorum sensing signals, and various lipids. Furthermore, we describe that specific metabolites are induced in the presence of the antibiotic trimethoprim only in SCFM2 when compared to LB. Herein, C13-acyl-homoserine lactone, a quorum sensing signal previously not known to be produced by B. cenocepacia as well as pyochelin-type siderophores were exclusively detected during growth in SCFM2 in the presence of trimethoprim. The comparative metabolomics approach described in this study provides insight into environment-dependent production of secondary metabolites by B. cenocepacia strains and suggests future work which could identify personalized strain-specific regulatory mechanisms involved in production of secondary metabolites. Investigations into whether antibiotics with different mechanisms of action induce similar metabolic alterations will inform development of combination treatments aimed at effective clearance of Burkholderia spp. pathogens.
Highlights
Infections by Burkholderia cenocepacia lead to life-threatening disease in immunocompromised individuals, including those living with cystic fibrosis (CF)
We employed an untargeted metabolomic approach to compare the metabolomes of three different strains of B. cenocepacia namely, C5424, K56-2, and J2315 when cultured in SCFM2 and laboratory medium (LB) in triplicate (Fig. 1a)
Comparative metabolomic analysis was carried out in the presence and absence of trimethoprim, which is an antibiotic used clinically for treatment of Burkholderia infections[40]. This antibiotic is known to upregulate biosynthetic pathways involved in production of secondary metabolites in B. thailandensis and in the selected strains of B. cenocepacia in LB, but its effect has not been investigated in SCFM241–43
Summary
Infections by Burkholderia cenocepacia lead to life-threatening disease in immunocompromised individuals, including those living with cystic fibrosis (CF). Previous work has demonstrated that nutrient availability at infection sites is associated with phenotypic changes in CF pathogens, including increased v irulence[23,24] Along these lines, clinical B. cenocepacia isolates cultured in a minimal medium supplemented with 12.5% (w/v) CF sputum were shown to exhibit differential expression of genes involved in virulence processes, such as antimicrobial resistance, iron uptake, protection against reactive oxygen/nitrogen species, motility, and secretion[25]. It is evident that nutrient composition is an important consideration for developing a clinically relevant in vitro model of CF sputum to be used in comparative metabolomic studies To this end, an assortment of artificial sputum media formulations have been established for studying CF pathogens in vitro that overcome the challenges with the inherent heterogeneity associated with culturing in sputum from patients[22,23,26,27,28,29,30,31]. While no individual laboratory model completely captured gene expression profiles observed during P. aeruginosa CF infections, the combination of SCFM2 and murine lung infection model came c losest[39]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
