Fig. 1: Distribution and phylogenetic analysis of Chinese S. sonnei strains, including the outbreak strains.

a shows the regional distribution of Chinese S. sonnei isolates, including sporadic and outbreak strains. There were 307 Chinese strains, including 155 outbreak strains and 152 sporadic strains from different regions of China. b shows the temporal distribution of Chinese S. sonnei isolates, including sporadic and outbreak strains. The outbreak strains were collected in 2015, 2016, 2019, and 2020. c shows a phylogenetic tree of global S. sonnei strains, displaying the position of Chinese S. sonnei strains, including the cef^Razi^R isolates as well as the six outbreak strains. The rings, from outer to inner, labeled with different colors indicate the cef^Razi^R and non-cef^Razi^R phenotypes, the isolation regions, geographical origin, and outbreak locations, respectively. Divergence dates are given on the major nodes in the tree. The map was created using publicly available data (https://www.webmap.cn/main.do?method=index). Source data are provided as a Source Data file. cef^Razi^R coresistance to ceftriaxone and azithromycin.