Bdellovibrio bacteriovorus inhibits Staphylococcus aureus biofilm formation and invasion into human epithelial cells.
Bdellovibrio bacteriovorus HD100 is a predatory bacterium that attacks many Gram-negative human pathogens. A serious drawback of this strain, however, is its ineffectiveness against Gram-positive strains, such as the human pathogen Staphylococcus aureus. Here we demonstrate that the extracellular proteases produced by a host-independent B. bacteriovorus (HIB) effectively degrade/inhibit the formation of S. aureus biofilms and reduce its virulence. A 10% addition of HIB supernatant caused a 75% or greater reduction in S. aureus biofilm formation as well as 75% dispersal of pre-formed biofilms. LC-MS-MS analyses identified various B. bacteriovorus proteases within the supernatant, including the serine proteases Bd2269 and Bd2321. Tests with AEBSF confirmed that serine proteases were active in the supernatant and that they impacted S. aureus biofilm formation. The supernatant also possessed a slight DNAse activity. Furthermore, treatment of planktonic S. aureus with the supernatant diminished its ability to invade MCF-10a epithelial cells by 5-fold but did not affect the MCF-10a viability. In conclusion, this study illustrates the hitherto unknown ability of B. bacteriovorus to disperse Gram-positive pathogenic biofilms and mitigate their virulence.
1] School of Life Sciences, Ulsan National Institute of Science and Technology [2].
Ajay K
AK
Monnappa
1] School of Life Sciences, Ulsan National Institute of Science and Technology [2].
Mohammed
M
Dwidar
UNIST Central Research Facility, Ulsan National Institute of Science and Technology.
Jeong Kon
JK
Seo
UNIST Central Research Facility, Ulsan National Institute of Science and Technology.
Jin-Hoe
JH
Hur
School of Life Sciences, Ulsan National Institute of Science and Technology.
Robert J
RJ
Mitchell
D001501:Bdellovibrio / Q000502:physiology*; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D001940:Breast / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D002853:Chromatography, Liquid; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology*; D005260:Female; D006801:Humans; D011480:Protease Inhibitors / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000378:metabolism*; D013203:Staphylococcal Infections / Q000382:microbiology / Q000517:prevention & control*; D013211:Staphylococcus aureus / Q000472:pathogenicity*; D053719:Tandem Mass Spectrometry; D014774:Virulence
D011480:Protease Inhibitors; D012697:Serine Endopeptidases