The alternative sigma factor sigma54 has been implicated in diverse functions within the cells. In this study, we have constructed an rpoN mutant of @entity796 and investigated its importance as a target for antimicrobial agents, such as @entity5176 and @entity2888 . The stationary-phase cells of the rpoN mutant displayed a survival rate approximately 15 times higher than that of the wild-type cells in the presence of @entity5176 and @entity2888 . The stationary phase led to substantial production of @entity28907 by the @entity796 rpoN mutant. @entity28907 synthesis correlated with decreased susceptibility to antimicrobial agents. Quantitative real-time PCR revealed that stationary-phase cells of the rpoN mutant grown without an antimicrobial agent had approximately 4- to 140- and 2- to 14-fold-higher levels of transcripts of the pvdS and vqsR genes, respectively, than the wild-type strain. In the presence of an antimicrobial agent, levels of pvdS and vqsR transcripts were elevated 400- and 5-fold, respectively, in comparison to the wild-type levels. Flow cytometry assays using a green fluorescent protein reporter demonstrated increased expression of the vqsR gene in the rpoN mutant throughout growth. A pvdS mutant of @entity796 , deficient in @entity28907 production, was shown to be susceptible to biapenem. These findings suggest that rpoN is involved in tolerance to antimicrobial agents in @entity796 and that its tolerant effect is partly dependent on increased @entity28907 production and vqsR gene expression.

rpoN gene of @entity796 alters its susceptibility to XXXX and @entity2888 .

@entity5176 :: ('MESH:D015363', 'Chemical') :: ['quinolones'] @entity28907 :: ('MESH:C042453', 'Chemical') :: ['Pyoverdine', 'pyoverdine'] @entity796 :: ('287', 'Species') :: ['Pseudomonas aeruginosa', 'P. aeruginosa'] @entity2888 :: ('MESH:D015780', 'Chemical') :: ['carbapenems']
@entity5176 :: (MESH:D015363,Chemical) :: ['quinolones']
