AmgRS‐mediated envelope stress‐inducible expression of the mexXY multidrug efflux operon of Pseudomonas aeruginosa

MicrobiologyOpen

Calvin Ho-Fung Lau¹  Thomas Krahn²  Christie Gilmour²  Erin Mullen² 

[1] E-mail address: 关键词: Efflux;    envelope stress;    multidrug;    Pseudomonas aeruginosa;    two‐component system;   

DOI  :  10.1002/mbo3.226

来源: Wiley

【 摘 要 】

Abstract

AmgRS is an envelope stress-responsive two-component system and aminoglycoside resistance determinant in Pseudomonas aeruginosa that is proposed to protect cells from membrane damage caused by aminoglycoside-generated mistranslated polypeptides. Consistent with this, a ΔamgR strain showed increased aminoglycoside-promoted membrane damage, damage that was largely absent in AmgRS-activated amgS-mutant strains. Intriguingly, one such mutation, V121G, while providing for enhanced resistance to aminoglycosides, rendered P. aeruginosa susceptible to several ribosome-targeting nonaminoglycoside antimicrobials that are inducers and presumed substrates of the MexXY-OprM multidrug efflux system. Surprisingly, the amgS_V121G mutation increased mexXY expression threefold, suggesting that export of these nonaminoglycosides was compromised in the amgS_V121G mutant. Nonetheless, a link was established between AmgRS activation and mexXY expression and this was confirmed in studies showing that aminoglycoside-promoted mexXY expression is dependent on AmgRS. While nonaminoglycosides also induced mexXY expression, this was not AmgRS-dependent, consistent with these agents not generating mistranslated polypeptides and not activating AmgRS. The aminoglycoside inducibility of mexXY was abrogated in a mutant lacking the AmgRS target genes htpX and PA5528, encoding a presumed cytoplasmic membrane-associated protease and a membrane protein of unknown function, respectively. Thus, aminoglycoside induction of mexXY is a response to membrane damage and activation of the AmgRS two-component system.

【 授权许可】

CC BY   
© 2014 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

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