Frequency and expression of mutacin biosynthesis genes in isolates of Streptococcus mutans with different mutacin-producing phenotypes

• Published in: Journal of medical microbiology Vol. 57; no. 5; pp. 626 - 635
• Main Authors: Kamiya, Regianne Umeko, Hofling, Jose Francisco, Goncalves, Reginaldo Bruno
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.05.2008; Society for General Microbiology
• Subjects: Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Bacteriocins - biosynthesis; Bacteriocins - genetics; Bacteriology; Biological and medical sciences; Enterococcus faecalis; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial - physiology; Genes, Bacterial; Genotype; Infectious diseases; Medical sciences; Microbiology; Miscellaneous; Phenotype; Staphylococcus aureus; Staphylococcus epidermidis; Streptococcus mutans; Streptococcus mutans - classification; Streptococcus mutans - genetics; Streptococcus mutans - metabolism; Streptococcus pyogenes; Streptococcaceae; Phenotype; Microbiology; Bacteria; Micrococcales; Isolate; Biosynthesis; Gene expression; Streptococcus mutans
• DOI: 10.1099/jmm.0.47749-0
• ISSN: 0022-2615

Department of Oral Diagnosis, Microbiology and Immunology Division, Piracicaba Dental School, Campinas University, Piracicaba, SP, Brazil Correspondence Reginaldo Bruno Gonçalves reginald{at}fop.unicamp.br Received 4 November 2007 Accepted 23 January 2008 The aim of this study was to analyse the frequency and expression of biosynthesis genes in 47 Streptococcus mutans isolates with different mutacin-producing phenotypes. Detection of the frequency and expression of genes encoding mutacin types I, II, III and IV were carried out by PCR and semi-quantitative RT-PCR, respectively, using primers specific for each type of biosynthesis gene. In addition, a further eight genes encoding putative bacteriocins, designated bsm 283 , bsm 299 , bsm 423 , bsm 1889c , bsm 1892c , bsm 1896 , bsm 1906c and bsm 1914 , were also screened. There was a high phenotypic diversity; some Streptococcus mutans isolates presented broad antimicrobial spectra against other Streptococcus mutans clinical isolates, including bacteria resistant to common antibiotics, as well as Staphylococcus aureus , Staphylococcus epidermidis , Enterococcus faecalis and Streptococcus pyogenes . The expression frequency of the bsm gene was higher than that of the previously characterized mutacins (I–IV). There was no positive correlation between the number of indicator strains inhibited (antimicrobial spectra) and the number of biosynthesis genes expressed (Spearman correlation test, r =–0.03, P >0.05). In conclusion, the high diversity of mutacin-producing phenotypes, associated with high frequency of expression of the biosynthesis genes screened, reveals a broad repertoire of genetic determinants encoding antimicrobial peptides that can act in different combinations. Abbreviations: CSP, competence-stimulating peptide.