Streptococcus mutans clonal variation revealed by multilocus sequence typing.
Streptococcus mutans is the major pathogen of dental caries, a biofilm-dependent infectious disease, and occasionally causes infective endocarditis. S. mutans strains have been classified into four serotypes (c, e, f, and k). However, little is known about the S. mutans population, including the clonal relationships among strains of S. mutans, in relation to the particular clones that cause systemic diseases. To address this issue, we have developed a multilocus sequence typing (MLST) scheme for S. mutans. Eight housekeeping gene fragments were sequenced from each of 102 S. mutans isolates collected from the four serotypes in Japan and Finland. Between 14 and 23 alleles per locus were identified, allowing us theoretically to distinguish more than 1.2 x 10(10) sequence types. We identified 92 sequence types in these 102 isolates, indicating that S. mutans contains a diverse population. Whereas serotype c strains were widely distributed in the dendrogram, serotype e, f, and k strains were differentiated into clonal complexes. Therefore, we conclude that the ancestral strain of S. mutans was serotype c. No geographic specificity was identified. However, the distribution of the collagen-binding protein gene (cnm) and direct evidence of mother-to-child transmission were clearly evident. In conclusion, the superior discriminatory capacity of this MLST scheme for S. mutans may have important practical implications.
Nakano
Kazuhiko
K
Departments of Pediatric Dentistry, Osaka University Graduate School of Dentistry, 1-8 Yamada-oka, Suita, Osaka 565-0871, Japan.
Lapirattanakul
Jinthana
J
Nomura
Ryota
R
Nemoto
Hirotoshi
H
Alaluusua
Satu
S
Grönroos
Lisa
L
Vaara
Martti
M
Hamada
Shigeyuki
S
Ooshima
Takashi
T
Nakagawa
Ichiro
I
D000328:Adult; D000483:Alleles; D015373:Bacterial Typing Techniques / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics*; D005260:Female; D005387:Finland; D005798:Genes, Bacterial; D005838:Genotype; D005843:Geography; D006801:Humans; D018445:Infectious Disease Transmission, Vertical; D007564:Japan; D017720:Molecular Epidemiology / Q000379:methods; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA; D013290:Streptococcal Infections / Q000382:microbiology / Q000635:transmission; D013295:Streptococcus mutans / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification
D004269:DNA, Bacterial