Multidrug-resistant tuberculosis (MDR-TB) poses one of the greatest threats to global health, as highlighted by new research from the Swiss Tropical and Public Health Institute (Swiss TPH). Despite the introduction of the new six-month treatment regimen recommended by the World Health Organization (WHO), studies indicate alarming trends of resistance among the drug-resistant bacteria responsible for the disease.
Every year, over 10 million people become infected with tuberculosis (TB), leading to approximately 1.25 million deaths globally, making it the most widespread infectious disease. Countries such as India, Central Asia, and Southern Africa are particularly hard-hit by TB. The WHO’s new treatment plan, known as BPaL(M), introduced two years ago, aims to reduce the time people need to be treated for MDR-TB and has shown improved safety and effectiveness rates during clinical trials.
Yet, according to findings published recently in the New England Journal of Medicine, the spread of drug-resistant strains among patients is rapidly becoming apparent, raising significant concerns over new protocols. Sébastien Gagneux, head of the Department of Medical Parasitology and Infection Biology at Swiss TPH and the study's lead author, stated, "Although the new treatment regimen is a turning point for patients suffering from MDR-TB, we anticipated the bacterium, Mycobacterium tuberculosis, would pose challenges." Gagneux emphasized the importance of examining how these bacteria would respond to the global rollout of the new therapy.
The research, conducted collaboratively with the National Center for Tuberculosis and Lung Diseases (NCTLD) based in Tbilisi, Georgia, explored whether resistance to the new medications had emerged and if such resistance was transmissible between patients. The study evaluated the genomes of nearly 90,000 M. tuberculosis strains from various countries, identifying 514 resistant strains, which were found across 27 nations on four continents. Alarmingly, 28 percent of these high-resistant strains were attributed to human-to-human transmission.
Postdoctoral researcher Galo A. Goig remarked, "We had prior indications of resistance formation but were unaware of the extent to which transmission contributed to the spread of these highly resistant strains." While the total number of cases remains relatively low, the trend of significant inter-patient transmission within just two years of implementing the new regimen raises serious questions about the treatment's efficacy.
The study results convey grave implications for health policy and antibiotic resistance. Co-author Chloé Loiseau pointed out, "The development of these new medications took many years; hence, it is pivotal to introduce such therapies alongside strong diagnostic and monitoring frameworks to prevent resistance from developing." The need for enhanced diagnostic tools and improved infection control measures is underscored to stem the spread of these resistant strains and maintain the treatment’s effectiveness.
Antimicrobial resistance remains one of the foremost threats to global health, as also emphasized by Gagneux. He stated, "The emergence of these highly drug-resistant TB strains underlines the persistent challenge of antibiotic resistance and the pressing need for proactive measures to avoid entering a 'post-antibiotic era.'" The study, backed by the Swiss National Science Foundation and the European Research Council, stresses the importance of vigilance and action alongside the introduction of new TB therapies.
Despite the introduction of new antibiotic agents for TB treatment, experts fear bacteria will continue to find ways to evade these new medications. The Swiss TPH has made considerable contributions toward battling TB by participating actively on five continents, focusing on research, strengthening health systems, and collaborating on clinical studies to develop new TB diagnostics, drugs, and vaccines.
Given the complex nature of tuberculosis and the multifaceted approach required to combat it effectively, stakeholders worldwide must prioritize improvements to monitoring and control of TB to mitigate the impact of drug-resistant strains. A comprehensive strategy involving global health organizations, local governments, and healthcare providers is necessary to optimize treatment outcomes and address the looming threat posed by MDR-TB.
Addressing TB and its resistant strains requires collective international action, innovative research, and sustained investment—all aimed at preventing the disease from becoming even more formidable. With the future efficacy of TB treatments at stake, the global community must act swiftly.