Restriction of Arginine Induces Antibiotic Tolerance inStaphylococcus aureus

Staphylococcus aureusis responsible for a substantial number of invasive infections globally each year. These infections are problematic because they are frequently recalcitrant to antibiotic treatment, particularly when they are caused by Methicillin-ResistantStaphylococcus aureus(MRSA). Antibiotic tolerance, the ability for bacteria to persist despite normally lethal doses of antibiotics, is responsible for most antibiotic treatment failure in MRSA infections. To understand how antibiotic tolerance is induced,S. aureusbiofilms exposed to multiple anti-MRSA antibiotics (vancomycin, ceftaroline, delafloxacin, and linezolid) were examined using both quantitative proteomics and transposon sequencing. These screens indicated that arginine metabolism is involved in antibiotic tolerance within a biofilm and led to the hypothesis that depletion of arginine withinS. aureuscommunities can induce antibiotic tolerance. Consistent with this hypothesis, inactivation ofargH,the final gene in the arginine synthesis pathway, induces antibiotic tolerance under conditions in which the parental strain is susceptible to antibiotics. Arginine restriction was found to induce antibiotic tolerance via inhibition of protein synthesis. Finally, althoughS. aureusfitness in a mouse skin infection model is decreased in anargHmutant, its ability to survivein vivoduring antibiotic treatment with vancomycin is enhanced, highlighting the relationship between arginine metabolism and antibiotic tolerance duringS. aureusinfection. Uncovering this link between arginine metabolism and antibiotic tolerance has the potential to open new therapeutic avenues targeting previously recalcitrantS. aureusinfections.