Finding Hidden Links in TB Transmission: KDCA Adopts Whole-Genome Sequencing

The Korea Disease Control and Prevention Agency is overhauling its system for identifying TB transmission routes by analyzing the entire genetic information of the TB bacterium.

The Korea Disease Control and Prevention Agency said on the 4th that it would switch its TB genotyping system to whole-genome sequencing (WGS). WGS reads and analyzes the entire genome of the TB bacterium.

About 17,000 new TB cases were reported in South Korea last year. The government aims to reduce the TB incidence rate to 20 or fewer cases per 100,000 people by 2027.

The Korea Disease Control and Prevention Agency has used analyses of genetic links among TB bacteria as scientific evidence to help identify transmission routes when TB outbreaks are suspected in places such as schools and nursing homes.

However, the previous method compared only part of the TB bacterium’s genetic information, limiting its ability to identify transmission routes for patients whose contact with one another had not been confirmed.

The newly adopted WGS method analyzes all approximately 4.4 million base pairs of the TB bacterium to precisely compare the similarity of bacteria from different patients.

This makes it possible to detect subtle genetic differences that were difficult to distinguish using the previous method, allowing more accurate identification of transmission links between patients that are difficult to establish through epidemiological investigations alone.

The Korea Disease Control and Prevention Agency plans to apply WGS to drug-resistant TB cases with unclear transmission routes. It will also continue to analyze patterns in the spread of TB bacteria in South Korea and trends in drug-resistant TB outbreaks using accumulated genomic data.

Lim Seung-kwan, commissioner of the Korea Disease Control and Prevention Agency, said, "The adoption of WGS will make it possible to analyze transmission patterns among TB patients more precisely." He added, "We expect to link the analysis results with epidemiological investigations to identify TB transmission early and use the findings to prevent further spread."