Frequency of Mycobacterium tuberculosis Among M. tuberculosis Complex Strains Isolated from Clinical Specimen / 대한임상미생물학회지

ABSTRACT

BACKGROUND: Rapid and accurate detection of Mycobacterium tuberculosis (MTB) is of primary importance for infection control and selection of anti-tuberculosis drugs. However, most clinical laboratories report MTB complex (MTC) without reporting MTB because MTC comprising MTB, Mycobacterium bovis, Mycobacterium africanum, Mycobacterium microti, Mycobacterium caprae and Mycobacterium pinnipedii have 99.9% similarity at the nucleotide level and identical 16S rRNA sequences. This study was conducted to analyze the species frequency of MTC isolates obtained from clinical specimen.METHODS: Of 310 MTC isolates obtained from clinical samples in a tertiary care hospital from February 2017 to August 2018, MolecuTech Real TB-Taq (YD Diagnostics, Korea) real-time PCR was performed, specifically to detect MTB. For DNA showing MTB negative results by MTB-specific real-time PCR or pyrazinamide-resistant strains, PCR-based MTC typing, spoligotyping, and exact tandem repeat D gene sequencing were performed.RESULTS: All the 310 MTC isolates were identified to be MTB. Two MTB strains of East-African-Indian 4-Vietnam genotype, which have not been reported in Korea, were also found.CONCLUSION: There was no zoonotic tuberculosis in this study. Since we investigated only 310 MTC isolates detected in only one medical institution, multi-center study is needed to accurately know the prevalence of zoonotic tuberculosis in Korea.