Transmission as a Key Driver of Resistance to the New Tuberculosis Drugs

Multidrug-resistant tuberculosis (MDR-TB) is a growing public health issue, with the World Health Organization promoting new antibiotic regimens. The global burden of MDR-TB is largely due to patient-to-patient transmission of drug-resistant Mycobacterium tuberculosis. Resistance to BPaL/M, used to treat MDR-TB, could spread. However, resistance to a single drug can reduce the competitive fitness of M. tuberculosis, making it less transmissible. A 13-year study analyzed the genomes of 6926 clinical M. tuberculosis isolates in Georgia, identifying 60 highly drug-resistant strains. The study found that 28% of these strains belonged to one of four genomic clusters, indicating patient-to-patient transmission.