Biofilm formation by group A Streptococcus: a role for the streptococcal regulator of virulence (Srv) and streptococcal cysteine protease (SpeB).
Recently, biofilms have become a topic of interest in the study of the human pathogen group A Streptococcus (GAS). In this study, we sought to learn more about the make-up of these structures and gain insight into biofilm regulation. Enzymic studies indicated that biofilm formation by GAS strain MGAS5005 required an extracellular protein and DNA component(s). Previous results indicated that inactivation of the transcriptional regulator Srv in MGAS5005 resulted in a significant decrease in virulence. Here, inactivation of Srv also resulted in a significant decrease in biofilm formation under both static and flow conditions. Given that production of the extracellular cysteine protease SpeB is increased in the srv mutant, we tested the hypothesis that increased levels of active SpeB may be responsible for the reduction in biofilm formation. Western immunoblot analysis indicated that SpeB was absent from MGAS5005 biofilms. Complementation of MGAS5005Deltasrv restored the biofilm phenotype and eliminated the overproduction of active SpeB. Inhibition of SpeB with E64 also restored the MGAS5005Deltasrv biofilm to wild-type levels.
Doern
Christopher D
CD
Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
Roberts
Amity L
AL
Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
Hong
Wenzhou
W
Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
Nelson
Jessica
J
Salem College, Winston-Salem, NC 27101, USA.
Lukomski
Slawomir
S
Mary Babb Randolph Cancer Center, School of Medicine, West Virginia University, Morgantown, WV 26506, USA.|Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV 26506, USA.
Swords
William E
WE
Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
Reid
Sean D
SD
Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D003470:Culture Media; D005098:Exotoxins / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D006801:Humans; D008855:Microscopy, Electron, Scanning; D009154:Mutation; D013297:Streptococcus pyogenes / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics
D001426:Bacterial Proteins; D003470:Culture Media; D005098:Exotoxins; C027951:erythrogenic toxin