Extensively Drug-Resistant (XDR) Salmonella Typhi Outbreak by Waterborne Infection — Beijing Municipality, China, January–February 2022

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC? Typhoid fever remains a major public health problem in developing countries. Waterborne typhoid fever affects an estimated 27 million people worldwide each year. Decades of indiscriminate antibiotic usage has driven the emergence and spread of multidrug-resistant (MDR) and even extensively drug-resistant (XDR) Salmonella Typhi (S. Typhi) strains. WHAT IS ADDED BY THIS REPORT? By combining the epidemiological investigations, bacterial isolation from patients and household water, whole genome sequencing and drug resistance analysis, we identified a waterborne typhoid fever outbreak caused by XDR S. Typhi in Beijing municipality. This was the first report of the XDR S. Typhi triggered outbreak in Beijing, which was also rare in China. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE? This report highlights the importance of ensuring access to affordable and safe drinking water, improved sanitation, and waste management systems for resource-constrained urban populations. Typhoid fever caused by XDR S. Typhi is still a severe public health threat.