Staphylococcus aureus
is 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-Resistant
Staphylococcus 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. aureus
biofilms 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 within
S. aureus
communities can induce antibiotic tolerance. Consistent with this hypothesis, inactivation of
argH,
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, although
S. aureus
fitness in a mouse skin infection model is decreased in an
argH
mutant, its ability to survive
in vivo
during antibiotic treatment with vancomycin is enhanced, highlighting the relationship between arginine metabolism and antibiotic tolerance during
S. aureus
infection. Uncovering this link between arginine metabolism and antibiotic tolerance has the potential to open new therapeutic avenues targeting previously recalcitrant
S. aureus
infections.
Significance Statement
Methicillin-Resistant
Staphylococcus aureus
(MRSA) is a leading bacterial cause of morbidity and mortality worldwide. Despite the availability of numerous antibiotics with
in vitro
efficacy against MRSA, there are still high rates of antibiotic treatment failure in
S. aureus
infections, suggesting antibiotic tolerance is common during human infections. Here, we report a direct connection between the metabolism of arginine, an essential amino acid in
S. aureus
, and tolerance to multiple classes of antibiotics. This represents a key pathway towards broad antibiotic tolerance in
S. aureus
and therefore an attractive target to help repotentiate current antibiotics and potentially reduce treatment failure.