Dissecting the regulation of bile-induced biofilm formation in Staphylococcus aureus

Loading...
Thumbnail Image
Files
Date
2016-08-01
Authors
Ulluwishewa, Dulantha
Wang, Liang
Pereira, Callen
Flynn, Stephanie
Cain, Elizabeth
Stick, Stephen
Reen, F. Jerry
Ramsay, Joshua P.
O'Gara, Fergal
Journal Title
Journal ISSN
Volume Title
Publisher
Microbiology Society
Published Version
Research Projects
Organizational Units
Journal Issue
Abstract
Aspiration of bile into the cystic fibrosis (CF) lung has emerged as a prognostic factor for reduced microbial lung biodiversity and the establishment of often fatal, chronic pathogen infections. Staphylococcus aureus is one of the earliest pathogens detected in the lungs of children with CF, and once established as a chronic infection, strategies for its eradication become limited. Several lung pathogens are stimulated to produce biofilms in vitro in the presence of bile. In this study, we further investigated the effects of bile on S. aureus biofilm formation. Most clinical S. aureus strains and the laboratory strain RN4220 were stimulated to form biofilms with sub-inhibitory concentrations of bovine bile. Additionally, we observed bile-induced sensitivity to aminoglycosides, which we exploited in a bursa aurealis transposon screen to isolate mutants reduced in aminoglycoside sensitivity and augmented in bile-induced biofilm formation. We identified five mutants that exhibited hypersensitivity to bile with respect to bile-induced biofilm formation, three of which carried transposon insertions within gene clusters involved in wall teichoic acid (WTA) biosynthesis or transport. Strain TM4 carried an insertion between the divergently oriented tagH and tagG genes, which encode the putative WTA membrane translocation apparatus. Ectopic expression of tagG in TM4 restored a wild-type bile-induced biofilm response, suggesting that reduced translocation of WTA in TM4 induced sensitivity to bile and enhanced the bile-induced biofilm formation response. We propose that WTA may be important for protecting S. aureus against exposure to bile and that bile-induced biofilm formation may be an evolved response to protect cells from bile-induced cell lysis.
Description
Keywords
Aminoglycosides , Anti-bacterial agents , ATP-binding cassette transporters , Bile , Biofilms , Cell wall , Cystic fibrosis , DNA transposable elements , Humans , Lung , Microbial sensitivity tests , Protein transport , Staphylococcal infections , Staphylococcus aureus , Teichoic Acids , Cystic fibrosis , Staphylococcus , Gastro-esophageal reflux
Citation
Ulluwishewa, D., Wang, L., Pereira, C., Flynn, S., Cain, E., Stick, S., Reen, F. J., Ramsay, J. P. and O’Gara, F. (2016) 'Dissecting the regulation of bile-induced biofilm formation in Staphylococcus aureus', Microbiology, 162(8), pp. 1398-1406. doi: 10.1099/mic.0.000317
Copyright
© The Authors 2016. The definitive peer reviewed, edited version of this article is published in Microbiology, 162, 8, 2016, https://doi.org/10.1099/mic.0.000317