JKAOH Journal of Korean Academy of Oral Health

ISSN(Print) 1225-388X ISSN(Online) 2093-7784

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Original Article

Journal of Korean Academy of Oral Health 2020; 44(1): 34-40

Published online March 30, 2020 https://doi.org/10.11149/jkaoh.2020.44.1.34

Copyright © Journal of Korean Academy of Oral Health.

Molecular epidemiology and characterization of Streptococcus mutans strains in Korea

Se-Yeon Kim1, Il Kown Bae2, Jung-Ha Lee1, Jeong Hwan Shin3, Jin-Bom Kim1

1Department of Preventive and Community Dentistry, School of Dentistry, Pusan National University, Yangsan, 2Department of Dental Hygiene, College of Health and Welfare, Silla University, 3Department of Laboratory Medicine, Inje University College of Medicine, Busan, Korea

Received: December 16, 2019; Revised: February 12, 2020; Accepted: February 25, 2020

Abstract

Objectives: We investigated the characteristics of Streptococcus mutans in the national culture collection from Korea. Twenty-nine (dental plaque, n=27; endodontic infections, n=1; blood, n=1) isolates were included in this study.
Methods: Antimicrobial susceptibilities were tested using the disk diffusion test. Multilocus sequence typing (MLST), serotyping, and collagen-binding genes were used for polymerase chain reaction (PCR) and direct sequencing. A collagen-binding (to assess the adhesion properties) assay was performed. S. mutanss demonstrated high susceptibility to antimicrobial agents. Differences in collagen-binding abilities of the cnm-positive and -negative groups were compared using the Mann-Whitney U test (P<0.05).
Results: MLST analyses revealed 25 sequence types (STs), 17 of which (ST213-ST229) contained new alleles. The strains were classified into four serotypes with the c type encompassing 79.3% of all strains, while the e, f, and k types representing 6.9% each. Analysis of the cnm and cbm genes, which encode the two surface adhesin components of S. mutanss, revealed three cnm-positive strains, each displaying greater adhesion ability than those of the cnm-negative strains.
Conclusions: This study highlights the presence of a wide variety of S. mutanss genotypes in Korea. These findings may provide useful information regarding the pathogenesis of infectious diseases, such as dental caries.

Keywords: Adhesion, Bacteremia, Collagen binding, MLST, Infection, Inflammation, Streptococcus mutans