Differential gene expression profile of Shigella dysenteriae causing bacteremia in an immunocompromised individual

Abstract

Aim: Shigella species has varying levels of virulence gene expression with respect to different sites of infection. In this study, the differential gene expression of S. dysenteriae in response to its site of infection was analyzed by transcriptomics. Methods: This study includes four clinical Shigella isolates. Transcriptomics was done for the stool and blood samples of a single patient. Isolates were screened for the presence of antimicrobial resistance genes. Results: The majority of genes involved in invasion were highly expressed in the strain isolated from the primary site of infection. Additionally, antimicrobial resistance (dhfr1A, sulII, blaOXA. blaCTX-M-1 and qnrS) genes were identified. Conclusion: This study provides a concise view of the transcriptional expression of clinical strains and provides a basis for future functional studies on Shigella spp. Lay abstract Shigella infection is restricted to the gastrointestinal tract and rarely causes fatal extra-intestinal complications like bacteremia. There are limited studies available from India on molecular characterization of Shigella spp. In this study, we characterized four Shigella isolates obtained from bloodstream infections. Shigella spp. isolated from the stool and blood of one representative patient was further sequenced to study the differential gene expression profile. The differential protein expression by S. dysenteriae observed in this study demonstrates that it has a specific response to particular intracellular environments. Further, the in vivo mechanism of Shigellae invasion are difficult to fully study until the intracellular environment is mimicked in vitro. To the best of our knowledge, this is the first Indian study that compared the gene expression profile of clinical Shigella strains.