The Korea Disease Control and Prevention Agency (KDCA) is overhauling its tuberculosis genotyping system to base it on whole-genome sequencing (WGS), aiming to pinpoint how the disease spreads between patients. Where the agency previously compared only portions of the tuberculosis bacterium's genetic code, it will now analyze all of its roughly 4.4 million base pairs to establish transmission links with greater precision.
The KDCA said on the 4th that it is introducing whole-genome sequencing into the genotyping analysis used when clusters of tuberculosis cases are suspected at schools, nursing homes and other facilities. The current method compares only parts of the bacterium's genetic information, limiting the agency's ability to identify transmission routes when contact between patients cannot be confirmed.
Whole-genome sequencing compares the entire genetic sequence of the bacterium, allowing even minute genetic differences between strains to be detected. That makes it possible to identify transmission links between patients that epidemiological investigation alone could not connect.
The agency plans to apply the new method to drug-resistant tuberculosis cases with unclear transmission routes as well. It will also use the accumulated genomic data to analyze how tuberculosis strains are spreading in South Korea and how drug-resistant cases are trending.
About 17,000 new tuberculosis cases were reported in the country last year. The government aims to cut the incidence rate to 20 cases per 100,000 people or fewer by 2027.
"The adoption of whole-genome sequencing allows us to identify the characteristics of transmission between tuberculosis patients more precisely," KDCA Commissioner Lim Seung-kwan said. "We will link the analysis results to epidemiological investigations and use them to block further transmission."
