title: Mutacins and bacteriocins like genes in Streptococcus mutans isolated from participants with high, moderate, and low salivary count.
abstract: OBJECTIVE
  To detect S. mutans producers of mutacins and bacteriocins like substances (BLIS) from saliva of participants with low, moderate, and high salivary counts.
  
  
  METHODS
  123 strains of S. mutans were obtained from participants with low, moderate, and high salivary counts (age 18 and 20 years old) and their antibacterial capacity analyzed. By using PCR amplification, the expression levels of mutacins and BLIS genes were studied (expressed in arbitrary units/ml) in all three levels.
  
  
  RESULTS
  S. mutans strains from participants with low salivary counts show high production of mutacins (63%). In contrast, participants with moderate and high salivary counts depict relatively low levels of mutacins (22 and 15%, respectively). Moreover, participants with low salivary counts showed high expression levels of genes encoding mutacins, a result that correlates with the strong antimicrobial activity of the group. Participants with moderate and high salivary counts however depict low expression levels of mutacin related genes, and little antimicrobial activity. No BLIS were detected in any of the groups studied.
  
  
  CONCLUSIONS
  S. mutans isolated from the saliva of participants with low bacterial counts have significant antibacterial capacity compared to that of participants with moderate and high salivary counts. The superior lethality of S. mutans in participants with low salivary counts is likely due to the augmented expression of mutacin- related genes.
authors.affiliation: Departamento de Microbiología, Facultad de Ciencias de la Salud, Universidad de Talca, Chile.
authors.forename: Carolina
authors.initials: C
authors.lastname: Soto
authors.affiliation: Departamento de Microbiología, Facultad de Ciencias de la Salud, Universidad de Talca, Chile.
authors.forename: Carlos
authors.initials: C
authors.lastname: Padilla
authors.affiliation: Departamento de Microbiología, Facultad de Ciencias de la Salud, Universidad de Talca, Chile. Electronic address: olobos@utalca.cl.
authors.forename: Olga
authors.initials: O
authors.lastname: Lobos
mesh_terms: D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001430:Bacteriocins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology; D004269:DNA, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction / Q000379:methods; D012463:Saliva / Q000378:metabolism / Q000382:microbiology*; D013295:Streptococcus mutans / Q000235:genetics* / Q000302:isolation & purification*; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D004269:DNA, Bacterial
keywords: Bacteriocin like; Mutacins; Salivary count; Streptococcus mutans