Study Finds 3,489 Typhoid Strains Driving Global XDR Spread, Threatening Last Oral Drug
Updated
Updated · ScienceAlert · May 29
Study Finds 3,489 Typhoid Strains Driving Global XDR Spread, Threatening Last Oral Drug
3 articles · Updated · ScienceAlert · May 29
Genome sequencing of 3,489 S. Typhi samples from 2014-2019 found extensively drug-resistant strains are rapidly displacing non-resistant typhoid in South Asia and spreading abroad.
Nearly 200 international transmission events have been identified since 1990, with resistant strains reaching Southeast Asia, East and Southern Africa, and also the UK, US and Canada.
By 2019, the first XDR strain detected in Pakistan in 2016 had become the country's dominant genotype, while quinolone-resistance mutations had already exceeded 85% of cases across five Asian countries by the early 2000s.
Azithromycin is now the only remaining oral antibiotic for typhoid, and the study found resistance mutations to that drug are also spreading, raising the risk that all oral treatments could fail.
With more than 13 million typhoid cases reported in 2024 and untreated infections fatal in up to 20% of cases, researchers urged wider use of typhoid conjugate vaccines and development of new antibiotics.
A typhoid superbug is spreading globally. How prepared are hospitals for this post-antibiotic era infection?
As the last oral antibiotic for typhoid fails, what is the world's plan B for treatment?
With a new typhoid vaccine, are we ignoring the permanent solution of clean water and sanitation?
13 Million Cases and Rising: The Alarming Spread of XDR Typhoid, Azithromycin Resistance, and the Global Vaccine Response
Overview
Extensively drug-resistant (XDR) typhoid fever is spreading rapidly worldwide, driven by strains of Salmonella Typhi that now resist most antibiotics. This crisis is especially severe in South Asia, where typhoid remains a major cause of illness and death. The last effective oral antibiotic, azithromycin, is at risk of losing its effectiveness, making treatment options dangerously limited. As a result, there is an urgent need for widespread use of typhoid conjugate vaccines in endemic countries to prevent further spread. Without expanded prevention and control measures, the threat of untreatable typhoid could become a global health catastrophe.