Identification of nonserotypeable Shigella spp. using genome sequencing: a step forward.

Aim: Sequencing technology has replaced conventional methods in identifying and characterizing bacterial pathogens. We characterized 23 nonserotypeable Shigella that biochemically resembled Shigella spp. using whole genome sequencing.

Materials & methods: Genome sequences were analyzed using online tools based on 16S rRNA, k-mer, gyr B sequences and analysis of O-antigen arrangement was done using PATRIC database for species identification. Sequence types, plasmid types, antimicrobial resistance and virulence genes were also investigated.

Results: The SpeciesFinder using 16S rRNA sequences identified only 74% of the isolates, whereas KmerFinder and gyr B sequence analysis identified 100% of the isolates to its species level. Antimicrobial resistance, virulence and plasmid incompatibility groups were identified in all the isolates. Sequence types were determined.

Conclusion: This study shows that whole genome sequencing approach for Shigella O-antigen analysis has greater discriminative power than other methods using different bioinformatics pipeline for identification of nonserotypeable Shigella .