MexT modulates virulence determinants in Pseudomonas aeruginosa independent of the MexEF-OprN efflux pump.
Microb Pathog
; 47(4): 237-41, 2009 Oct.
Article
in En
| MEDLINE
| ID: mdl-19683048
ABSTRACT
In the human pathogen Pseudomonas aeruginosa, the LysR-family regulator MexT modulates the induction of the tripartite MexEF-OprN resistance nodulation-division multi-drug efflux system resulting in increased resistance to diverse antibiotics. The MexEF-OprN system is normally quiescent in wild-type cells, but is highly induced in nfxC-type phenotypic mutants in a MexT dependent manner. In addition to antibiotic resistance, induction of mexEF-oprN in nfxC-type mutants has been linked to reduced levels of homoserine lactone-dependent virulence traits, including pyocyanin, elastase, rhamnolipids and PQS and to reduced expression of type three secretion effector proteins. In this study, MexT is overexpressed in wild-type PAO1 and an isogenic mexEF deletion mutant to determine if MexT regulates diverse virulence phenotypes dependent or independent of MexEF-OprN. It is shown that MexT regulates type three secretion, pyocyanin production and early surface attachment independent of MexEF-OprN. In contrast, MexT modulation of the expression of the virulence genes rhlA, lasB and hcnB is dependent on MexEF-OprN, which apparently mediates these effects via efflux of cell-signaling intermediates. The data presented demonstrates that MexT may play a more global role in modulating P. aeruginosa virulence than previously reported and suggests that MexT regulates diverse targets that mediate phenotypic alterations independent of MexEF-OprN.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pseudomonas aeruginosa
/
Transcription Factors
/
Gene Expression Regulation, Bacterial
/
Virulence Factors
Type of study:
Prognostic_studies
Limits:
Humans
Language:
En
Journal:
Microb Pathog
Journal subject:
DOENCAS TRANSMISSIVEIS
/
MICROBIOLOGIA
Year:
2009
Type:
Article
Affiliation country:
Ireland