Genome-Wide Screening for Identification of Novel Toxin-Antitoxin Systems in Staphylococcus aureus

Abstract

Recent advances in genome sequencing and bioinformatics research have demonstrated that most pathogenic bacteria harbor a large number of chromosomally encoded toxin-antitoxin (TA) modules. However, little is known about the TA systems in S. aureus . Here, we newly identified four S. aureus TA systems using a combination of manual base-by-base screening and functional analysis in E. coli . Moreover, all toxins of the identified TA systems caused growth inhibition in the native host S. aureus . Although the newly identified TA systems did not exhibit sequence similarity with known bacterial TA systems, their orthologues were conserved only among other Staphylococcus species, indicating their uniqueness to staphylococci. Our approach opens the possibility for studying unannotated TA systems in various bacterial species.