Pseudomonas aeruginosa Cell Membrane Protein Expression from Phenotypically Diverse Cystic Fibrosis Isolates Demonstrates Host-Specific Adaptations

Abstract

Pseudomonas aeruginosa is a Gram-negative, nosocomial, highly adaptable opportunistic pathogen especially prevalent in immuno-compromised cystic fibrosis (CF) patients. The bacterial cell surface proteins are important contributors to virulence, yet the membrane subproteomes of phenotypically diverse P. aeruginosa strains are poorly characterized. We carried out mass spectrometry (MS)-based proteome analysis of the membrane proteins of three novel P. aeruginosa strains isolated from the sputum of CF patients and compared protein expression to the widely used laboratory strain, PAO1. Microbes were grown in planktonic growth condition using minimal M9 media, and a defined synthetic lung nutrient mimicking medium (SCFM) limited passaging. Two-dimensional LC-MS/MS using iTRAQ labeling enabled quantitative comparisons among 3171 and 2442 proteins from the minimal M9 medium and in the SCFM, respectively. The CF isolates showed marked differences in membrane protein expression in comparison with PAO1 including up-regulation of drug resistance proteins (MexY, MexB, MexC) and down-regulation of chemotaxis and aerotaxis proteins (PA1561, PctA, PctB) and motility and adhesion proteins (FliK, FlgE, FliD, PilJ). Phenotypic analysis using adhesion, motility, and drug susceptibility assays confirmed the proteomics findings. These results provide evidence of host-specific microevolution of P. aeruginosa in the CF lung and shed light on the adaptation strategies used by CF pathogens.

Identification of FDA-Approved Drugs as Antivirulence Agents Targeting the pqs Quorum-Sensing System of Pseudomonas aeruginosa

“…A major concern with respect to the use of anti-QS drugs for the treatment of CF pulmonary infection originates from evolutionary selection driving P. aeruginosa adaptation to the CF lung. Indeed, during chronic infections, CF isolates accumulate mutations that reduce the production of virulence factors, lead to the formation of mucoid biofilms, increase antibiotic resistance mainly as a consequence of efflux pump overexpression, and in some cases inactivate QS systems (93)(94)(95)(96). Since P. aeruginosa QS-defective mutants should be considered resistant to anti-QS drugs, the suitability of QS inhibition for CF therapy is under debate.…”

Characterization of the Pseudomonas aeruginosa NQR complex, a bacterial proton pump with roles in autopoisoning resistance

“…Although no studies have been conducted to elucidate the role of NQR in P. aeruginosa physiology, the data indicate that it has important functions in disease and in biofilm formation. Indeed, P. aeruginosa strains isolated from cystic fibrosis patients show an increase in NQR expression (84,85). Moreover, Pa-NQR subunits have been shown to be expressed by P. aeruginosa during biofilm formation (86,87), especially in the oxygen-rich, metabolically active regions of the biofilm, where bacteria are exposed to competing bacteria, antibacterial metabolites and antibiotics, and other varying environmental factors.…”

Identification of a Chemoreceptor in Pseudomonas aeruginosa That Specifically Mediates Chemotaxis Toward α-Ketoglutarate

“…In addition, P. aeruginosa was found to colonize (Walker et al, 2004) and infect different plants (Cao et al, 2001). A number of reports show that P. aeruginosa chemotaxis is necessary for efficient host colonization and virulence (Garvis et al, 2009; McLaughlin et al, 2012; Kamath et al, 2016; Schwarzer et al, 2016) and the interference with the motility and chemotaxis was proposed as an alternative strategy to block this pathogen (Erhardt, 2016). …”