title: Assessment of two multilocus sequence typing (MLST) schemes available for Streptococcus mutans.
abstract: OBJECTIVE
  Two multilocus sequencing typing (MLST) schemes are currently available for Streptococcus mutans. The first, introduced by Nakano et al. in 2007, consists of 8 conserved housekeeping genes. The second, introduced in 2010 by Do et al., includes 6 housekeeping genes and 2 putative virulence genes. The purpose of the current study was to compare the two MLST schemes for use in validating repetitive extragenic palindromic polymerase chain reaction (rep-PCR) genotypes.
  
  
  METHODS
  Thirty-three S. mutans isolates, representing the 11 most commonly occurring rep-PCR genotype groups, were selected for MLST. MLST was performed with SYBR Green™ PCR with published primers for both MLST schemes. Amplicons were purified, sequenced, and data checked against the www.PubMLST.org database for allelic and sequence type (ST) assignment. Discriminatory power, congruence, and convenience criteria were evaluated. Concatenated sequences for each scheme were analyzed using MEGA to generate phylogenetic trees using minimum evolution with bootstrap.
  
  
  RESULTS
  No significant difference in discriminatory power was observed between the two MLST schemes for S. mutans. Clonal clusters were consistent for both schemes. Overall, MLST demonstrated marginally greater discriminatory power than rep-PCR; however all methods were found to be congruent. New alleles and ST are reported for each scheme and added to the PubMLST database.
  
  
  CONCLUSIONS
  Clonality, supported by both methods and rep-PCR, indicates S. mutans genotypes are shared between unrelated subjects. Both Nakano and Do schemes demonstrates similar genotype discrimination for S. mutans isolates suggesting each are well designed and may be used to verify rep-PCR genotypes.
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, University of Alabama at Birmingham, SOD 304, 1720 2nd Avenue South, Birmingham, AL 35294-0007, USA. Electronic address: jenndoc@uab.edu.
authors.forename: Stephanie S
authors.initials: SS
authors.lastname: Momeni
authors.affiliation: Department of Pathology, School of Medicine & Dentistry, University of Alabama at Birmingham, WP 230, 619 19th Street South, Birmingham, AL 35249-7331, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Whiddon
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, University of Alabama at Birmingham, SOD 304, 1720 2nd Avenue South, Birmingham, AL 35294-0007, USA. Electronic address: kcheon@uab.edu.
authors.forename: Kyounga
authors.initials: K
authors.lastname: Cheon
authors.affiliation: Department of Pathology, School of Medicine & Dentistry, University of Alabama at Birmingham, WP 230, 619 19th Street South, Birmingham, AL 35249-7331, USA. Electronic address: moser@uab.edu.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Moser
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, University of Alabama at Birmingham, SOD 304, 1720 2nd Avenue South, Birmingham, AL 35294-0007, USA. Electronic address: nkc@uab.edu.
authors.forename: Noel K
authors.initials: NK
authors.lastname: Childers
mesh_terms: D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D009055:Mouth / Q000382:microbiology; D058885:Multilocus Sequence Typing / Q000379:methods*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D013295:Streptococcus mutans / Q000235:genetics* / Q000302:isolation & purification
keywords: Dental caries; Genetic diversity; Genotyping; MLST; Streptococcus mutans; rep-PCR