Pseudomonas aeruginosaIncreases Formation of Multidrug-Tolerant Persister Cells in Response to Quorum-Sensing Signaling Molecules

Abstract

ABSTRACTBacterial persister cells constitute a small portion of a culture which is tolerant to killing by lethal doses of bactericidal antibiotics. These phenotypic variants are formed in numerous bacterial species, including those with clinical relevance like the opportunistic pathogenPseudomonas aeruginosa. Although persisters are believed to contribute to difficulties in the treatment of many infectious diseases, the underlying mechanisms affecting persister formation are not well understood. Here we show that even thoughP. aeruginosacultures have a significantly smaller fraction of multidrug-tolerant persister cells than cultures ofEscherichia coliorStaphylococcus aureus, they can increase persister numbers in response to quorum-sensing-related signaling molecules. The phenazine pyocyanin (and the closely related molecule paraquat) and the acyl-homoserine lactone 3-OC12-HSL significantly increased the persister numbers in logarithmicP. aeruginosaPAO1 or PA14 cultures but not inE. coliorS. aureuscultures.