Evaluation of zebrafish as a model to study the pathogenesis of the opportunistic pathogen Cronobacter turicensis

Abstract

Bacteria belonging to the genus Cronobacter spp. have been recognized as causative agents of life-threatening systemic infections, primarily in premature, low-birth weight and/or immune-compromised neonates. Knowledge remains scarce regarding the underlying molecular mechanisms of disease development. In this study, we evaluated the use of a zebrafish model to study the pathogenesis of Cronobacter turicensis LMG 23827T, a clinical isolate responsible for two fatal sepsis cases in neonates. Here, the microinjection of approximately 50 colony forming units (CFUs) into the yolk sac resulted in the rapid multiplication of bacteria and dissemination into the blood stream at 24 h post infection (hpi), followed by the development of a severe bacteremia and larval death within 3 days. In contrast, the innate immune response of the embryos was sufficiently developed to control infection after the intravenous injection of up to 104 CFUs of bacteria. Infection studies using an isogenic mutant devoid of surviving and replicating in human macrophages (ΔfkpA) showed that this strain was highly attenuated in its ability to kill the larvae. In addition, the suitability of the zebrafish model system to study the effectiveness of antibiotics to treat Cronobacter infections in zebrafish embryos was examined. Our data indicate that the zebrafish model represents an excellent vertebrate model to study virulence-related aspects of this opportunistic pathogen in vivo.

20 Years of fish immunotoxicology – what we know and where we are

“…Zhang et al 2008), or to visualize -by means of transgenic fish -immunotoxic processes in the live animal (e.g. Fehr et al 2015). Furthermore, since early life stages of fish, in particular the embryonic stage, possess only innate but no adaptive immunity (e.g.…”

Two highly adhesive lactic acid bacteria strains are protective in zebrafish infected with Aeromonas hydrophila by evocation of gut mucosal immunity

“…As an alternative model for understanding immune system function, zebrafish has been adopted to study the relationship between immunity and diseases/infection (Fehr et al . ; Shan et al . ; Yang et al .…”

Zebrafish Granulocyte Colony-Stimulating Factor Receptor Maintains Neutrophil Number and Function throughout the Life Span

“…Infection studies involved injection of embryos at 72 hpf with 2 to 5 nl of ϳ9 ϫ 10 10 CFU E. coli expressing green fluorescent protein (GFP) (no. 25922GFP; ATCC) into the venous return using a published protocol (45), with bacteria quantified by plate counting and visualized and imaged using an Olympus MVX10 fluorescence microscope and DP72 camera. Survival of infected embryos and juvenile fish was monitored by regular visual inspection and displayed as a Kaplan-Meier curve, with statistical significance determined using a log-rank (Mantel-Cox) test.…”