Establishing a Percutaneous Infection Model Using Zebrafish and a Salmon Pathogen

Area of Science:

• Microbiology
• Aquatic Animal Health
• Zebrafish Models

Background:

• The skin microbiome plays a crucial role in host defense against pathogens.
• Understanding the interplay between environmental stressors, host defenses, and microbial communities is vital for aquaculture and wildlife health.

Purpose of the Study:

• To investigate the relationship between intrinsic skin bacterial flora and susceptibility to pathogen infection in zebrafish.
• To determine the impact of cold stress, physical injury, and pathogen challenge on the fish skin microbiome and infection dynamics.

Main Methods:

• Development of a percutaneous infection model in zebrafish using the pathogen Yersinia ruckeri.
• Application of cold stress (28°C to 20°C) and physical injury (needle prick).
• Analysis of fish skin bacterial flora composition using 16S rDNA metagenomics.

Main Results:

• Cold stress combined with injury and Yersinia ruckeri challenge led to fatal infections in zebrafish.
• Cold stress significantly altered the skin bacterial flora, with Yersinia ruckeri dominating in infected fish.
• Antibiotic disruption of the intrinsic skin flora facilitated Yersinia ruckeri colonization, even without physical injury.

Conclusions:

• The intrinsic skin bacterial flora of fish provides a crucial defense against pathogen colonization.
• Environmental stressors like cold can disrupt this protective flora, increasing susceptibility to opportunistic pathogens.
• Maintaining a healthy skin microbiome is essential for preventing disease outbreaks in fish populations.