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ID 115749
Author
Matoba, Masaki Tokushima University
Takao, Ayuko Tsurumi University
Whiley, Robert A. Queen Mary University of London
Maeda, Nobuko Tsurumi University
Keywords
Streptococcus intermedius
intermedilysin
screening
MsgA
NanA
LacR
Content Type
Journal Article
Description
Streptococcus intermedius is a member of the normal human commensal flora and secretes a human-specific cytolysin intermedilysin (ILY) as a major virulence factor. Expression of ily is repressed by LacR and loss-of-function mutations of LacR are observed in many ILY high-producing strains isolated from deep-seated abscesses, suggesting that high ILY production is necessary for increased virulence. However, because ILY exhibits no β-hemolysis on animal blood agar plates, differentiating ILY high- and low-producing strains using conventional laboratory methods is not possible. Interestingly, S. intermedius also produces glycosidases, including MsgA and NanA, which exhibit N-acetyl-β-D-glucosaminidase and neuraminidase activities, respectively. Moreover, MsgA expression, but not NanA, is negatively regulated by LacR. Here we measured the activities of MsgA, NanA and ILY in strains isolated from clinical specimens and dental plaque to determine the correlation between these glycosidase activities and ILY hemolytic activity. Hemolytic activity showed a strong positive correlation with MsgA and a weak negative correlation with NanA activities. Therefore, we calculated the ratio of MsgA and NanA activity (M/N ratio). This value showed a stronger positive correlation (r = 0.81) with ILY hemolytic activity and many strains with high M/N ratios (> 2) were ILY high-producers with loss-of-function mutations in LacR.
Description Alternative
Rapid screening method for highly pathogenic S. intermedius strains based on the ratio of activities of MsgA and NanA resulting from lacR mutations.
Journal Title
FEMS Microbiology Letters
ISSN
15746968
03781097
NCID
AA00193861
Publisher
Federation of European Microbiological Societies|Oxford University Press
Volume
365
Issue
3
Start Page
fnx258
Published Date
2017-12-06
Remark
This is a pre-copyedited, author-produced version of an article accepted for publication in FEMS Microbiology Letters following peer review. The version of record Toshifumi Tomoyasu, Masaki Matoba, Ayuko Takao, Atsushi Tabata, Robert A Whiley, Nobuko Maeda, Hideaki Nagamune, Rapid screening method for detecting highly pathogenic Streptococcus intermedius strains carrying a mutation in the lacR gene, FEMS Microbiology Letters, Volume 365, Issue 3, February 2018, fnx258 is available online at: https://doi.org/10.1093/femsle/fnx258
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DOI (Published Version)
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language
eng
TextVersion
Author
departments
Bioscience and Bioindustry