Osong Public Health and Research Perspectives

Semi Jeon

3 Articles

Molecular Typing of Mycobacterium intracellulare Using Pulsed-Field Gel Electrophoresis, Variable-Number Tandem-Repeat Analysis, Mycobacteria Interspersed Repetitive-Unit-Variable-Number Tandem Repeat Typing, and Multilocus Sequence Typing: Molecular Characterization and Comparison of Each Typing Methods: Semi Jeon, Nara Lim, Seungjik Kwon, Taesun Shim, Misun Park, Bum-Joon Kim, Seonghan Kim; Osong Public Health Res Perspect. 2014;5(3):119-130. Published online June 30, 2014; DOI: https://doi.org/10.1016/j.phrp.2014.04.003

Abstract PDF: Objectives
Mycobacterium intracellulare is the major causative agent of nontuberculous mycobacteria-related pulmonary infections. The strain typing of M. intracellulare is important for the treatment and control of its infections. We compared the discrimination capacity and effective value of four different molecular typing methods.
Methods
Antibiotic susceptibility testing, hsp65 and rpoB sequencing, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), mycobacteria interspersed repetitive-unit-variable-number tandem-repeat analysis (MIRU-VNTR), and VNTR assay targeting 44 M. intracellulare isolates obtained from patients with pulmonary infections were performed.
Results
All the antibiotic susceptibility patterns had no association with the molecular and sequence types tested in this study; however, the molecular and sequence types were related with each other. PFGE gave best results for discriminatory capacity, followed by VNTR, MLST, and MIRU-VNTR.
Conclusion
The high discriminatory power of PFGE, VNTR, and MLST is enough for differentiating between reinfection and relapse, as well as for other molecular epidemiological usages. The MLST could be regarded as a representative classification method, because it showed the clearest relation with the sequence types.

Multiplex Real-time Polymerase Chain Reaction Assays for Simultaneous Detection of Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus: Jie Yeun Park, Semi Jeon, Jun Young Kim, Misun Park, Seonghan Kim; Osong Public Health Res Perspect. 2013;4(3):133-139. Published online June 30, 2013; DOI: https://doi.org/10.1016/j.phrp.2013.04.004

Abstract PDF: Objectives
A multiplex real-time polymerase chain reaction (RT-PCR) method was developed for the identification of three Vibrio species: Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus.
Methods
Specific primers and probes targeting the hlyA, tlh, and vvhA genes were selected and used for multiplex real-time PCR to confirm the identification of V. cholerae, V. parahaemolyticus, and V. vulnificus, respectively. This method was applied to screen Vibrio species from environmental samples and combining it with a culture-based method, its effectiveness was evaluated in comparison with culture-based methods alone.
Results
Specific PCR fragments were obtained from isolates belonging to the target species, indicating a high specificity of this multiplex real-time PCR. No cross-reactivity with the assay was observed between the tested bacteria. The sensitivity of the multiplex real-time PCR was found to have a lower limit of 10⁴ colony-forming units/reaction for all three Vibrio species. The combination strategy raised the isolation ratio of all three Vibrio species 1.26- to 2.75-fold.
Conclusion
This assay provides a rapid, sensitive, and specific technique to detect these three Vibrio species in the environment.

Multiplex Real-Time Polymerase Chain Reaction-Based Method for the Rapid Detection of gyrA and parC Mutations in Quinolone-Resistant Escherichia coli and Shigella spp.: Junyoung Kim, Semi Jeon, Hyungjun Kim, Misun Park, Soobok Kim, Seonghan Kim; Osong Public Health Res Perspect. 2012;3(2):113-117. Published online June 30, 2012; DOI: https://doi.org/10.1016/j.phrp.2012.04.004

Abstract PDF: Two real-time polymerase chain reaction assays were developed to detect mutations in codons 83 and 87 in gyrA and in codons 80 and 91 in parC, the main sites that causes quinolone resistance in pathogenic Escherichia coli and Shigella spp. isolates. These assays can be employed as a useful method for controlling infections caused by quinolone-resistant E coli and Shigella isolates.

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