Staphylococcus aureus virulence factors identified by using a high-throughput Caenorhabditis elegans-killing model

Area of Science:

• Microbiology
• Pathogen Research
• Genetics

Background:

• Staphylococcus aureus is a significant human pathogen.
• It can also kill the model organism Caenorhabditis elegans.
• Understanding S. aureus virulence factors is crucial for developing new treatments.

Purpose of the Study:

• To identify novel Staphylococcus aureus genes involved in virulence.
• To investigate the role of these genes in C. elegans killing.
• To assess the virulence of identified mutants in a mammalian model.

Main Methods:

• Construction of a large Tn917 transposon insertion library in S. aureus.
• Screening the library for mutants with reduced C. elegans killing ability.
• Transduction of promising mutants into different S. aureus strains.
• Evaluation of selected mutants in a murine renal abscess model.

Main Results:

• A library of 2,950 S. aureus transposon insertion mutants was created.
• Twenty-one mutants showed attenuated killing of C. elegans.
• Twelve unique gene/location mutants were identified, with 5 not previously implicated in virulence studies.
• One mutant with an insertion in the nagD gene exhibited reduced virulence in a mouse model.
• Tn917 transposon insertions showed a bias towards the DNA replication terminus.

Conclusions:

• Novel S. aureus virulence genes were identified using a C. elegans killing assay.
• The nagD gene is implicated in S. aureus virulence in both invertebrate and mammalian models.
• This study provides new targets for understanding and combating S. aureus infections.