Application of WGS PCR Method in Assisting Identification of Shigella spp.

Application of WGS PCR Method in Assisting Identification of Shigella spp.

Shigella spp. is the causative agent of shigellosis and one of the category 2 communicable diseases in Taiwan, and it causes an average of 104 local cases per year in recent 5 years. As traditional biochemical tests and serotyping cannot accurately identify some strains of Shigella spp., this becomes an obstacle for clinical laboratories to report shigellosis cases to the health departments. To improve the identification of Shigella spp., we tested clinical strains of Shigella spp. with the whole-genomic-based PCR (WGS-PCR) method. WGS-PCR method allows detection of both the phylogenic clades of Shigella spp. and the IpaH gene, an invasive gene plasmid of either Shigella spp. or EIEC. Among the 30 confirmed strains of Shigella spp., the results of WGS-PCR were 100% concordant with that of serotyping on group B, C and D strains, but only 20% consistency was found on group A strains. While using WGS-PCR to test 29 suspicious strains of Shigella spp., 2 group B strains and 2 group D strains were identified, indicating that WGS-PCR may clearly detect suspicious strains. As WGS-PCR method is a low-cost method, we recommend using WGS-PCR as a supplementary test for serotyping.