Uncovering the pathogenic mechanisms of Cronobacter turicensis: A dual transcriptomics study using a zebrafish larvae...

Cronobacter (C.) is an emerging opportunistic pathogen representing a significant cause of mortality in neonatal patients with bacteremia and meningitis. The pathobiology of Cronobacter mediated meningitis has primarily been investigated using in vitro models. In this study, we used zebrafish to investigate in vivo the infection strategy of the sepsis/meningitis-causing strain C. turicensis z3032 (LMG 23827T) and the immune response of zebrafish larvae after central nervous system (CNS) invasion. Global gene expression profiles of both organisms were analyzed using RNA-Seq.

Injection of bacteria into the yolk sac resulted in proliferation of bacteria and translocation to different tissues, including the brain. Infected larval heads were obtained by microdissection and dual RNA-sequencing was performed on host and pathogen simultaneously.

A total of 1432 genes in C. turicensis z3032 and 80 genes in zebrafish were found to be differentially expressed. Upregulated virulence genes in C. turicensis included those encoding for denitrification and anaerobic respiration, chemotaxis, surface structures, and secretion systems. In zebrafish, transcriptional changes included inflammatory processes, cytokine mediated signaling pathways, and NF-kB signaling as the primary GO categories for upregulated genes in response to infection.

The dual transcriptomics approach provided a unique opportunity to create a comprehensive catalog of differentially expressed genes in both the pathogen and the host, offering new insights into the infection strategies of C. turicensis and zebrafish immune response.