- Isolation and Characterization of the Mutans Streptococci from the Dental Plaques in Koreans
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So Young Yoo , Seon Joo Park , Dong Ki Jeong , Kwang-Won Kim , Sung-Hoon Lim , Sang-Ho Lee , Son-Jin Choe , Young-Hyo Chang , Insoon Park , Joong-Ki Kook
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J. Microbiol. 2007;45(3):246-255.
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DOI: https://doi.org/2535 [pii]
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Abstract
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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.
- Prevalence of Putative Periodontopathogens in Subgingival Dental Plaques from Gingivitis Lesions in Korean Orthodontic Patients
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Seung Mi Lee , So Young Yoo , Hwa-Sook Kim , Kwang-Won Kim , Young-Joo Yoon , Sung-Hoon Lim , Hee-Young Shin , Joong-Ki Kook
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J. Microbiol. 2005;43(3):260-265.
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DOI: https://doi.org/2215 [pii]
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Abstract
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The objective of this study was to detect and compare the presence of periodontopathogens in the subgingival plaques of gingivitis lesions in adults who wore fixed orthodontic appliances, as opposed to adults who did not wear any orthodontic appliances. Thirty-six individuals participated in this study. Ninteen of these subjects did not wear any orthodontic appliances, and these subjects comprised the control group. The other 17 individuals had been wearing fixed orthodontic appliances for at least 3 months each. After a periodontal examination, we collected subgingival plaque samples from the gingivitis lesions of each patient. Using PCR based on 16S rDNA, we detected the presence of 6 putative periodontopathogenic species, Treponema denticola, Porphyromonas gingivalis, Tannerella forsythia (formerly Bacteroides forsythus), Prevotella nigrescens, Prevotella intermedia, and Actinobacillus actinomycetemcomitans. With regard to the presence of individual periodontopathogens, we found that T. forsythia, T. denticola, and P. nigrescens were significantly more common in the samples obtained from the orthodontic patients than in the samples obtained from the non-orthodontic patient controls. Our results indicate that the local changes associated with the wearing of fixed orthodontic appliances may affect the prevalence of periodontopathogens in subgingival dental plaques.
- Identification of Non-mutans Streptococci Organisms in Dental Plaques Recovering on Mitis-Salivarius Bacitracin Agar Medium
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So Young Yoo , Pyung Sik Kim , Ho-Keel Hwang , Seong-Hoon Lim , Kwang-Won Kim , Son-Jin Choe , Byung-Moo Min , Joong-Ki Kook
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J. Microbiol. 2005;43(2):204-208.
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DOI: https://doi.org/2160 [pii]
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Abstract
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The objective of this study was to both isolate and identify non-mutans streptococci organisms (non-MSO) from dental plaques recovered on mitis-salivarius sucrose bacitracin agar (MSB) plates. The dental plaque samples, which had been collected from 63 human subjects, were diluted and plated on MSB. The bacteria growing on the MSB plates were then identified with biochemical tests, as well as with 16S rDNA cloning and sequencing techniques. Our data indicated that bacteria from 30 subjects had been recovered on the MSB plates. Among the 21 typical colonies selected from the 30 subjects, 12 colonies, derived from 10 subjects, were identified as non-MSO. These 12 colonies were determined to be Streptococcus anginosus (8 colonies), S. sanguinis (1 colony), and Pantoea agglomerans (3 colonies). These results strongly suggest that a new selective medium will be required for the reliable isolation of mutans streptococci.
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