Staphylococcus aureus Killing Assay of Caenorhabditis elegans

(Abstract) The Gram-positive bacterium Staphylococcus aureus is a human pathogen that displays virulence towards the nematode Caenorhabditis elegans. This property can be used to discover genes that are important for virulence in humans, because S. aureus possesses common virulence factors that are used in C. elegans and in humans to cause disease. S. aureus colonizes the C. elegans intestine, establishes an infection, and causes pathogenesis of the intestinal epithelium that ultimately kills the infected animal after 3 to 4 days (Sifri et al., 2003; Irazoqui et al., 2008; Irazoqui et al., 2010). The protocol described here is used to establish the rate of S. aureus-induced C. elegans death, which allows the comparison of wild type and mutant strains and thus ultimately aids in the identification of genes required either for S. aureus virulence or for C. elegans host defense. The assay can also be applied for antimicrobial drug discovery.