Inactivation of TCA cycle enhances Staphylococcus aureus persister cell formation in stationary phase

Abstract

Persister cells constitute a small subpopulation of bacteria that display remarkably high antibiotic tolerance and for pathogens such as Staphylococcus aureus are suspected as culprits of chronic and recurrent infections. Persisters formed during exponential growth are characterized by low ATP levels but less is known of cells in stationary phase. By enrichment from a transposon mutant library in S. aureus we identified mutants that in this growth phase displayed enhanced persister cell formation. We found that inactivation of either sucA or sucB, encoding the subunits of the α-ketoglutarate dehydrogenase of the tricarboxylic acid cycle (TCA cycle), increased survival to lethal concentrations of ciprofloxacin by 10–100 fold as did inactivation of other TCA cycle genes or atpA encoding a subunit of the F1F0 ATPase. In S. aureus, TCA cycle activity and gene expression are de-repressed in stationary phase but single cells with low expression may be prone to form persisters. While ATP levels were not consistently affected in high persister mutants they commonly displayed reduced membrane potential, and persistence was enhanced by a protein motive force inhibitor. Our results show that persister cell formation in stationary phase does not correlate with ATP levels but is associated with low membrane potential.

5-Methylindole Potentiates Aminoglycoside Against Gram-Positive Bacteria Including Staphylococcus aureus Persisters Under Hypoionic Conditions

“…Stationary-phase S. aureus cells, which are highly tolerant to bactericidal antibiotics (Keren et al, 2004), are usually considered as one type of S. aureus persisters (Allison et al, 2011;Wang et al, 2018). Therefore, our aforementioned observations suggested that 5M-indole enables aminoglycosides to kill S. aureus persisters.…”

A Novel LysR-Type Global Regulator RpvA Controls Persister Formation and Virulence inStaphylococcus aureus

“…Acetyl coenzyme A and succinate are important ingredients of the tricarboxylic acid (TCA) cycle, and their significant decrease in rpvA mutant indicates that RpvA has an inhibitory effect on TCA. Previous studies have confirmed that inactivation of TCA cycle enhances S. aureus persister formation in stationary phase (39). Inhibition of glycolysis and TCA cycle reduces bacterial ATP production and promotes bacterial transformation to persister (29–31).…”

“…Oxidative stress defense mechanism regulated by msaABCR operon is required for persistent and recurrent S. aureus infections (38). Stationary phase S. aureus persister formation is associated with low membrane potential (39), while phenol-soluble modulins limit S. aureus prsister cell formation (40). Deletion of ctaB can attenuate S. aureus growth and virulence in mice but enhanced the formation of persister cells in stationary phase (41).…”

Magnesium Links Starvation-Mediated Antibiotic Persistence to ATP

“…poly(dC)/RmlB transduces signals of starvation to mediated persistence in Pseudomonas aeruginosa. Two expected consequences of starvation, decreases in ATP levels and membrane potential, proved to be two important aspects in persister formation (3,10,11). However, there are still missing links such as signal sensing and regulatory mechanisms between starvation and ATP/membrane potential-mediated persister formation.…”

“…S4). Membrane potential has been found to be responsible for persister induction by inactivation of tricarboxylic acid (TCA) genes in S. aureus (11). However, a recent study showed that extracellular magnesium suppresses membrane potential-mediated hyperpolarization and protects Bacillus subtilis from ribosome-targeting antibiotics (23).…”