Zebrafish gut colonization by mCherry-labelled lactic acid bacteria

Area of Science:

• Microbiology
• Gastroenterology
• Zebrafish models

Background:

• Probiotic microorganisms need to colonize the host intestine to be effective.
• In vitro studies have explored microbial adhesion, but in vivo behavior remains less understood.
• Zebrafish offer a valuable vertebrate model for studying host-microbe interactions.

Purpose of the Study:

• To investigate the in vivo intestinal colonization ability of specific probiotic lactic acid bacteria using the zebrafish model.
• To develop and utilize a fluorescent labeling method for tracking probiotic bacteria within a living host.
• To compare the differential adhesion capabilities of selected Lactobacillus strains in vivo.

Main Methods:

• Fluorescently tagging Lactobacillus plantarum Lp90, L. plantarum B2, and Lactobacillus fermentum PBCC11.5 using the novel pRCR12 plasmid encoding the mCherry protein.
• Infecting germ-free zebrafish larvae with the labeled probiotic strains.
• Monitoring bacterial colonization and adhesion in vivo using fluorescence stereomicroscopy up to 3 days post-infection.

Main Results:

• Differential in vivo adhesion capabilities were observed among the tested probiotic strains.
• A time-dependent displacement of bacteria towards the posterior intestinal tract suggested transient colonization.
• Lactobacillus plantarum strains demonstrated more robust adhesion compared to Lactobacillus fermentum PBCC11.5.

Conclusions:

• The pRCR12 plasmid is an effective tool for fluorescently labeling Lactobacillus strains for in vivo studies.
• The zebrafish model is a powerful system for monitoring probiotic colonization and investigating microbial adhesion in vivo.
• Understanding in vivo colonization is crucial for developing effective probiotic therapies.