Findings have revealed that resistance to the newly recommended multidrug-resistant Tuberculosis (MDR-TB) treatment regimen by the World Health Organisation (WHO) is already being transmitted directly from one patient to another.
A recent study by the Swiss Tropical and Public Health Institute (Swiss TPH) reported that these resistant strains are being transmitted directly between patients, highlighting the need for immediate action and robust surveillance to curb the spread.
The study, published in the New England Journal of Medicine, analysed the genomes of nearly 90,000 Mycobacterium tuberculosis strains from various countries. The researchers identified 514 highly drug-resistant strains, 28 per cent of which were transmitted directly from one patient to another. These strains were resistant to older and newer treatment regimens found across 27 countries.
Head of the Department, Medical Parasitology and Infection Biology, Swiss TPH, Sébastien Gagneux, explained that while the new regimen is a game changer for MDR-TB patients, it needs to be studied in the long run.
“However, it was crucial to study how Mycobacterium tuberculosis would react to its global roll-out and now we know that resistance is emerging and being transmitted, which is worrying,” he said.
Gagneux stressed that to avoid a post-antibiotic era; the world must stay ahead in the constant race between drug development and bacterial resistance to prevent a ‘post-antibiotic era. “The rise of highly resistant TB strains is a stark reminder of this challenge,” he added.
Despite the preventive and curable nature of TB, the disease remains a global burden and one of the world’s deadliest infectious killers with MDR-TB posing a critical threat to global health.
As part of efforts to accelerate progress towards ending TB, WHO in 2022 endorsed the treatment regimen known as BPaLM, which is a six-month all-oral regimen.
BPaLM is a combination of bedaquiline, pretomanid, linezolid, and moxifloxacin for MDR-TB and its variant BPaL, is used for pre-extensively drug-resistant TB (pre-XDR-TB). Earlier clinical trials as reported by WHO showed a treatment success rate of 89 per cent, significantly higher than the 52 per cent success rate of older regimens.
This approach, as recommended by WHO, aimed to reduce treatment duration, improve efficacy, and lower costs compared to the older, longer treatment regimens. The trial also reported lower rates of treatment failure, death, and loss of follow-up.
Despite the promising results, a recent study shows that resistance to the new regimen is already emerging and spreading. The researchers stressed that the effectiveness of the new regimen depends on implementing robust diagnostic tools, improved infection control, and better surveillance systems to curb the transmission of resistant strains.
A post doctoral collaborator at Swiss TPH and co-author of the paper, Chloé Loiseau, called for improved diagnostic tools, infection control measures, and robust surveillance systems to prevent further spread of drug-resistant TB strains.
“These new drugs have taken many years to develop and to prevent drug resistance from emerging, it is essential to combine the deployment of these new regimens with robust diagnostics and surveillance systems,” she said.
However, the researchers warned that deploying these regimens without adequate diagnostic and surveillance systems risks accelerating drug resistance.
According to the WHO, TB caused approximately 1.3 million deaths in 2022, with nearly 30,000 people falling ill each day. Nigeria is no exception to this deadly disease and according to experts at The Global Fund; Nigeria currently has the highest number of TB cases in Africa with over 350,000 notified case findings in 2023 and an increase in the absolute number of Drug-Resistant Tuberculosis (DR-TB) cases from 2,897 in 2021 to 3,932 in 2022.
TB is a contagious bacterial disease caused by Mycobacterium tuberculosis that spreads through the air, affecting the lungs and other parts of the body. Some of its common symptoms include coughing, chest pain, weight loss, fever, and night sweats while multidrug-resistant TB occurs when the bacteria no longer respond to the two most effective first-line TB drugs.
