부산대학교 도서관

Pseudomonas aeruginosa PAO1, an opportunistic human pathogen, deploys several strategies to resist antibiotics. It uses multidrug efflux pumps, including the MexAB‐OprM pump, for antibiotic resistance, and it also produces hydrogen sulfide (H2S) that provides some defense against antibiotics. MexR functions as a transcriptional repressor of the mexAB‐oprM operon. MexR responds to oxidative stresses caused by antibiotic exposure, and it also displays a growth phase‐dependent derepression of the mexAB‐oprM operon. However, the intrinsic inducer has not been identified. Here, we report that P. aeruginosa PAO1 produced sulfane sulfur, including glutathione persulfide and inorganic polysulfide, produced from either H2S oxidation or from L‐cysteine metabolism. Sulfane sulfur directly reacted with MexR, forming di‐ and trisulfide cross‐links between two Cys residues, to derepress the mexAB‐oprM operon. Levels of cellular sulfane sulfur and mexAB‐oprM expression varied during growth, and both reached the maximum during the stationary phase of growth. Thus, self‐produced H2S and sulfane sulfur may facilitate antibiotic resistance via inducing the expression of antibiotic resistance genes. [ABSTRACT FROM AUTHOR]