Transmitted Extended-spectrum XDR Tuberculosis in Beijing

Drug-resistance to tuberculosis remains a major public health threat. Here, we report two cases of extended-spectrum XDR (XXDR) tuberculosis, resistant to most first and second-line agents. Correlation of whole-genome sequencing (WGS) and phenotypic testing was discordant, suggesting over-reliance on WGS may miss clinically relevant resistance in extensively drug-resistant disease.