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Open Access Highly Accessed Research article

TypA is involved in virulence, antimicrobial resistance and biofilm formation in Pseudomonas aeruginosa

Anke Neidig1, Amy TY Yeung2, Thibaut Rosay3, Beatrix Tettmann1, Nikola Strempel1, Martina Rueger1, Olivier Lesouhaitier3 and Joerg Overhage1*

Author Affiliations

1 Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces, PO Box 3640, Karlsruhe, 76021, Germany

2 Centre for Microbial Diseases & Immunity Research, University of British Columbia, 2259 Lower Mall, Vancouver, BC, Canada

3 Laboratory of Microbiology Signals and Microenvironment, LMSM EA 4312, University of Rouen, 55 rue Saint Germain, Evreux, 27000, France

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BMC Microbiology 2013, 13:77  doi:10.1186/1471-2180-13-77

Published: 9 April 2013

Abstract

Background

Pseudomonas aeruginosa is an important opportunistic human pathogen and is extremely difficult to treat due to its high intrinsic and adaptive antibiotic resistance, ability to form biofilms in chronic infections and broad arsenal of virulence factors, which are finely regulated. TypA is a GTPase that has recently been identified to modulate virulence in enteric Gram-negative pathogens.

Results

Here, we demonstrate that mutation of typA in P. aeruginosa resulted in reduced virulence in phagocytic amoebae and human macrophage models of infection. In addition, the typA mutant was attenuated in rapid cell attachment to surfaces and biofilm formation, and exhibited reduced antibiotic resistance to ß-lactam, tetracycline and antimicrobial peptide antibiotics. Quantitative RT-PCR revealed the down-regulation, in a typA mutant, of important virulence-related genes such as those involved in regulation and assembly of the Type III secretion system, consistent with the observed phenotypes and role in virulence of P. aeruginosa.

Conclusions

These data suggest that TypA is a newly identified modulator of pathogenesis in P. aeruginosa and is involved in multiple virulence-related characteristics.

Keywords:
Pseudomonas aeruginosa; Pathogen; TypA; Type III secretion system; Virulence; Dictyostelium discoideum; Macrophage; Biofilm; Resistance