Determination of Shigella sonnei Virulence using Caenorhabditis elegans Infection Model

• Published in: Asia-Pacific journal of molecular biology and biotechnology Vol. 30; p. 52
• Main Authors: Wong, Bao Chi, Tan, Hock Siew
• Format: Journal Article
• Language: English
• Published: Kuala Lumpur Malaysian Society for Molecular Biology and Biotechnology 01.06.2022
• Subjects: Accumulation; Bacteria; Bacterial diseases; Bacterial infections; Caenorhabditis elegans; Colonization; Fatalities; Fluorescence; Fluorescence microscopy; Guinea pigs; In vivo methods and tests; Infections; Life cycles; Microscopy; Nematodes; Pathogenesis; Rabbits; Shigella; Shigella sonnei; Strains (organisms); Virulence; Worms
• ISSN: 0128-7451

Introduction: Shigella is the second leading cause of diarrhoeal mortality, leading to more than 60 thousand deaths in children younger than five years. In vivo studies of Shigella were traditionally done on non-primate mammalians such as rabbits and guinea pigs with a long-life cycle. A soildwelling nematode Caenorhabditis elegans, however, is easy to handle and has a shorter life cycle. In this project we aim to demonstrate the usability of C. elegans for Shigella sonnei pathogenesis and virulence research. Methods: Age-synchronised C. elegans were exposed to different strains of S. sonnei. The most virulent S. sonnei strain was selected for further characterization. The bacterial colonization assay was done by plating out the bacteria present within the worms after infection. Fluorescence microscopy was also performed using the virulent S. sonnei strain tagged with RFP. Results: Two S. sonnei strains were tested in C. elegans, namely ATCC 29930 and ATCC 25922. Both ATCC strains were virulent towards the nematode. ATCC 29930 was the most virulent, causing 50% deaths within 5 days. Bacterial colonization assay showed the accumulation of live S. sonnei ATCC 29930 reaching its plateau after 72 hours. Fluorescence microscopy also showed that ATCC 29930 begins to accumulate in the nematode guts after 3 hours. Conclusion: The nematode C. elegans is a useful model to determine the virulence of bacteria as a preliminary screen. This can be done by determining the survival of nematode after bacterial infection, the quantification of bacterial accumulation within the worm, and fluorescence microscopy.