The Utility of a real-time polymerase chain reaction kit for differentiating between and the Beijing familythe.

Background: Tuberculosis (TB) is a severe public health challenge in Korea. Of all Mycobacterium tuberculosis (M. tb) strains, the Beijing genotype strain reportedly correlates with hypervirulence and drug resistance. Hence, an early identification of the Beijing genotype strain of M. tb plays a significant role in initial TB treatment. Kogenebiotech (KoRT-polymerase chain reaction [PCR]) has developed a real-time PCR 17 18 kit to determine the Beijing genotype strain classified as M. tb. To determine the feasibility of the commercially produced KoRT-PCR kit in identifying the M. tb strain.

Methods: We used 100 clinical isolates of M. tb and 100 non-M. tb samples for the assessment. We evaluated the overall concordance between the KoRT-PCR kit and the mycobacterial interspersed repetitive unite variable number tandem repeat typing kit (GenoScreen, Lille, France). Moreover, we measured the detection limits based on the chromosomal DNA copies for the KoRT-PCR kit. In addition, we determined the reproducibility among individual technicians using the KoRT-PCR.

Results: The KoRT-PCR kit successfully discriminated all M. tb (confidence interval [CI]: 96.38%-100.00% for both sensitivity and specificity) and Beijing genotype strain (CI: 95.70%-100.00% for sensitivity and 96.87%-100.00% for specificity). We confirmed no significant deviation in the reproducibility between the technicians.

Conclusions: The KoRT-PCR kit displayed sufficient capability of discriminating the Beijing genotype strain, which enabled the rapid identification of the Beijing genotype strain from the M. tb clinical isolates.