A galactose‐specific sugar: phosphotransferase permease is prevalent in the non‐core genome of Streptococcus mutans. (20th February 2013)

• Record Type: Journal Article
• Authors: Zeng, L.; Xue, P.; Stanhope, M.J.; Burne, R.A.
• Is Part Of: Molecular oral microbiology. Volume 28:Number 4(2013:Aug.)
• Page Start: 292
• Page End: 301
• Publication Date: 2013-02-20
• Subjects: Mouth -- Microbiology -- Periodicals; Respiratory infections -- Microbiology -- Periodicals; Mouth -- Diseases -- Immunological aspects -- Periodicals; 617.522
• DOI: 10.1111/omi.12025
• Languages: English
• ISSNs: 2041-1006

Abstract

<abstract abstract-type="main" id="omi12025-abs-0001"> <title>Summary</title> <p>Three genes predicted to encode the A, B and C domains of a sugar : phosphotransferase system (PTS) permease specific for galactose\(EII^Gal) were identified in the genomes of 35 of 57 recently sequenced isolates of <italic>Streptococcus mutans</italic>, the primary etiological agent of human dental caries. Mutants defective in the EII^Gal complex were constructed in six of the isolates and showed markedly reduced growth rates on galactose‐based medium relative to the parental strains. An EII^Gal‐deficient strain constructed using the invasive serotype <italic>f</italic> strain OMZ175 (OMZ/IIGal) expressed significantly lower PTS activity when galactose was present as the substrate. Galactose was shown to be an effective inducer of catabolite repression in OMZ175, but not in the EII^Gal‐deficient strain. In a mixed‐species competition assay with galactose as the sole carbohydrate source, OMZ/IIGal was less effective than the parental strain at competing with the oral commensal bacterium <italic>Streptococcus gordonii</italic>, which has a high‐affinity galactose transporter. Hence, a significant proportion of <italic>S. mutans</italic> strains encode a galactose PTS permease that could enhance the ability of these isolates to compete more effectively with commensal streptococci for galactose in salivary constituents and the diet.</p> </abstract>