Whole genome analysis reveals new insights into the molecular characteristics of NAP1/BI/027/ST1 clinical isolates in the People's Republic of China.

The epidemic new strain NAP1/BI/027/ST-1 of () causes more severe coliti and a higher mortality rate than historical strains. However, NAP1/BI/027/ST-1 ( RT027) infections have been rarely reported in Asia, particularly in China. The objective of this study was to strengthen the understanding of the molecular characterizations of RT027 in China. Two NAP1/BI/027/ST-1 were detected from two patients, and no additional isolates were found. Whole genome sequencing (WGS) was used to characterize two RT027 isolates and control strain CD6 (from Hong Kong), and comparative genomic analysis was performed to compare genomic differences between seven isolates from Mainland China, CD6, and 10 isolates from North America and Europe. The comparative genomic analysis revealed that isolates obtained from Mainlan China were outside of the two epidemic lineages, FQR1 and FQR2, and might have decreased virulence and transmissibility for outbreak. Furthermore, unique SNP mutations were detected in isolates obtained from Mainland China, which may affect the biological function of . We speculate that RT027 isolates in Mainland China may have different features, compared to those in North America and Europe.