Isolation and characterization of the mutans streptococci from the dental plaques in Koreans.
Mutans streptococci have been implicated as cariogenic bacteria in dental caries because they can produce high levels of dental caries-causing lactic acid and extracellular polysaccharide. The aim of this study was to isolate and characterize the mutans streptococci from the dental plaque obtained from Koreans. The dental plaque samples were collected from the anterior and molar teeth of both jaws in 155 subjects (aged 2 to 33.2 years, average age 13.7+/-4.7 years). The samples were diluted by 100-fold in 1x PBS and plated on mitis-salivarius bacitracin (MSB) agar plates. The mutans streptococci grown on MSB plates were screened by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) targeting dextranase gene (dex). The mutans streptococci were identified at the species level using a 16S rDNA sequencing comparison method. The biochemical tests were carried out to biotype the mutans streptococci. Ninety-five strains of the mutans streptococci out of 358 colonies, which were derived from 141 subjects, were isolated. Of them, 77 strains and 18 strains were Streptococcus mutans and Streptococcus sobrinus, respectively. The biotyping data showed that 62, 1, 20, 10, and 2 strains were biotypes I, II, IV, V and variant, respectively. Of the two strains of variant biotype, one strains was similar to biotype IV except that it was positive to the arginine hydrolysis test. We considered this one strain a new biotype, and classified it as biotype VII. In conclusion, S. mutans and its biotype I was most frequently isolated in Korean dental plaque. The mutans streptococci strains isolated in this study might be useful for the study of the pathogenesis and the prevention of dental caries.
Yoo
So Young
SY
Department of Oral Biochemistry, Chosun University, Gwang-ju, Republic of Korea.
Park
Seon Joo
SJ
Jeong
Dong Ki
DK
Kim
Kwang-Won
KW
Lim
Sung-Hoon
SH
Lee
Sang-Ho
SH
Choe
Son-Jin
SJ
Chang
Young-Hyo
YH
Park
Insoon
I
Kook
Joong-Ki
JK
D000293:Adolescent; D000328:Adult; D044466:Asian People; D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D003773:Dental Plaque / Q000382:microbiology*; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013295:Streptococcus mutans / Q000145:classification* / Q000302:isolation & purification*; D016986:Streptococcus sobrinus / Q000145:classification / Q000302:isolation & purification
D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S