Comparisons of Two Proteomic Analyses of Non-Mucoid and Mucoid Pseudomonas aeruginosa Clinical Isolates from a Cystic Fibrosis Patient

Rao, J. R.; Damron, F. Heath; Basler, Marek; DiGiandomenico, Antonio; Sherman, Nicholas E.; Fox, Jay W.; Mekalanos, John J.; Goldberg, Joanna B.

doi:10.3389/fmicb.2011.00162

Cited by 33 publications

(31 citation statements)

References 72 publications

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“…In this study, the mucoid strain 2192 has decreased amounts of HSI-I T6SS components, whereas the nonmucoid strain has increased HSI-I T6SS components (54). If the level of RsmA was increased due to AlgU in mucoid strain 2192, as presented here (Fig.…”

Section: Fig 10supporting

confidence: 55%

Pseudomonas aeruginosa AlgU Contributes to Posttranscriptional Activity by Increasing rsmA Expression in a mucA22 Strain

Stacey

Pritchett

2016

J Bacteriol

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Pseudomonas aeruginosa thrives in multiple environments and is capable of causing life-threatening infections in immunocompromised patients. RsmA is a posttranscriptional regulator that controls virulence factor production and biofilm formation. In this study, we investigated the expression and activity of rsmA and the protein that it encodes, RsmA, in P. aeruginosa mucA mutant strains, which are common in chronic infections. We determined that AlgU regulates a previously unknown rsmA promoter in P. aeruginosa. Western blot analysis confirmed that AlgU controls rsmA expression in both a laboratory strain and a clinical isolate. RNase protection assays confirmed the presence of two rsmA transcripts and suggest that RpoS and AlgU regulate rsmA expression. Due to the increased amounts of RsmA in mucA mutant strains, a translational leader fusion of the RsmA target, tssA1, was constructed and tested in mucA, algU, retS, gacA, and rsmA mutant backgrounds to examine posttranscriptional activity. From these studies, we determined that RsmA is active in mucA22 mutants, suggesting a role for RsmA in mucA mutant strains. Taken together, we have demonstrated that AlgU controls rsmA transcription and is responsible for RsmA activity in mucA mutant strains. We propose that RsmA is active in P. aeruginosa mucA mutant strains and that RsmA also plays a role in chronic infections. IMPORTANCEP. aeruginosa causes severe infections in immunocompromised patients. The posttranscriptional regulator RsmA is known to control virulence and biofilm formation. We identify a new rsmA promoter and determine that AlgU is important in the control of rsmA expression. Mutant mucA strains that are considered mucoid were used to confirm increased rsmA expression from the AlgU promoter. We demonstrate, for the first time, that there is RsmA activity in mucoid P. aeruginosa strains. Our work suggests that RsmA may play a role during chronic infections as well as acute infections. Pseudomonas aeruginosa produces a myriad of virulence factors and can cause both acute and chronic infections (1, 2). To survive and persist, P. aeruginosa must coordinate gene expression in response to changing environmental conditions. Global regulatory networks respond to changing environmental conditions to allow the physiological changes necessary for survival to be made. The P. aeruginosa genome encodes many global regulatory systems, including posttranscriptional regulators, such as RsmA. RsmA is important in regulating several virulence factors involved in acute and chronic infections (3).Acute infections are characterized by motility and expression of the type III secretion system (4). RsmA positively regulates both motility and type III secretion system expression (4-6). A defining characteristic of chronic infections is biofilm formation, which includes the production of exopolysaccharides, such as alginate, and the type VI secretion system (T6SS) (7,8). RsmA is a negative regulator of the exopolysaccharide gene psl and the first hemolysin-coregulated se...

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Section: Fig 10supporting

confidence: 55%

Pseudomonas aeruginosa AlgU Contributes to Posttranscriptional Activity by Increasing rsmA Expression in a mucA22 Strain

Stacey

Pritchett

2016

J Bacteriol

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“…The determinants of strain persistence in the CF lung of both adult and child patients for long periods remain unclear. Whilst phenotypic changes such as the conversion to a mucoid phenotype (Al-Aloul et al, 2004;Govan & Deretic, 1996;Rao et al, 2011) and the formation of biofilms (Costerton et al, 1999;Høiby et al, 2011;Luján et al, 2011) have been associated with transition of P. aeruginosa from acute to chronic infection, little is known regarding the precise genotypic characteristics that facilitate persistent colonization.…”

Section: Introductionmentioning

confidence: 99%

Modulation of gene expression by Pseudomonas aeruginosa during chronic infection in the adult cystic fibrosis lung

Harmer

Al-Nassafi

et al. 2013

Microbiology

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Chronic Pseudomonas aeruginosa infection is the leading cause of morbidity and mortality in cystic fibrosis (CF) patients. P. aeruginosa isolates undergo significant transcriptomic and proteomic modulation as they adapt to the niche environment of the CF lung and the host defences. This study characterized the in vitro virulence of isogenic strain pairs of P. aeruginosa epidemic or frequent clonal complexes (FCCs) and non-epidemic or infrequent clonal complexes (IFCCs) that were collected 5-8 years apart from five chronically infected adult CF patients. Strains showed a significant decrease in virulence over the course of chronic infection using a Caenorhabditis elegans slow-killing assay and in phenotypic tests for important virulence factors. This decrease in virulence correlated with numerous differentially expressed genes such as oprG, lasB, rsaL and lecB. Microarray analysis identified a large genomic island deletion in the IFCC strain pair that included type three secretion system effector and fimbrial subunit genes. This study presents novel in vitro data to examine the transcriptomic profiles of sequentially collected P. aeruginosa from CF adults. The genes with virulence-related functions identified here present potential targets for new therapies and vaccines against FCCs and IFCCs.

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“…aeruginosa is a ubiquitous aerobic Gram-negative bacterium that affects individuals with compromised immune systems and has a high intrinsic resistance to most antibiotics (13,14). P. aeruginosa possesses a large array of virulence factors, such as flagellum, pili, elastase, chitinase, lipase, and proteases (15)(16)(17).…”

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confidence: 99%

Efficacy and Safety of Liposomal Clarithromycin and Its Effect on Pseudomonas aeruginosa Virulence Factors

Alhajlan

Alhariri

Omri

2013

Antimicrob Agents Chemother

116

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We investigated the efficacy and safety of liposomal clarithromycin formulations with different surface charges against clinical isolates of Pseudomonas aeruginosa from the lungs of cystic fibrosis (CF) patients. The liposomal clarithromycin formulations were prepared by the dehydration-rehydration method, and their sizes were measured using the dynamic-light-scattering technique. Encapsulation efficiency was determined by microbiological assay, and the stabilities of the formulations in biological fluid were evaluated for a period of 48 h. The MICs and minimum bactericidal concentrations (MBCs) of free and liposomal formulations were determined with P. aeruginosa strains isolated from CF patients. Liposomal clarithromycin activity against biofilm-forming P. aeruginosa was compared to that of free antibiotic using the Calgary Biofilm Device (CBD). The effects of subinhibitory concentrations of free and liposomal clarithromycin on bacterial virulence factors and motility on agar were investigated on clinical isolates of P. aeruginosa. The cytotoxicities of the liposome preparations and free drug were evaluated on a pulmonary epithelial cell line (A549). The average diameter of the formulations was >222 nm, with encapsulation efficiencies ranging from 5.7% to 30.4%. The liposomes retained more than 70% of their drug content during the 48-h time period. The highly resistant strains of P. aeruginosa became susceptible to liposome-encapsulated clarithromycin (MIC, 256 mg/liter versus 8 mg/liter; P < 0.001). Liposomal clarithromycin reduced the bacterial growth within the biofilm by 3 to 4 log units (P < 0.001), significantly attenuated virulence factor production, and reduced bacterial twitching, swarming, and swimming motilities. The clarithromycin-entrapped liposomes were less cytotoxic than the free drug (P < 0.001). These data indicate that our novel formulations could be a useful strategy to enhance the efficacy of clarithromycin against resistant P. aeruginosa strains that commonly affect individuals with cystic fibrosis.

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Comparisons of Two Proteomic Analyses of Non-Mucoid and Mucoid Pseudomonas aeruginosa Clinical Isolates from a Cystic Fibrosis Patient

Cited by 33 publications

References 72 publications

Pseudomonas aeruginosa AlgU Contributes to Posttranscriptional Activity by Increasing rsmA Expression in a mucA22 Strain

Pseudomonas aeruginosa AlgU Contributes to Posttranscriptional Activity by Increasing rsmA Expression in a mucA22 Strain

Modulation of gene expression by Pseudomonas aeruginosa during chronic infection in the adult cystic fibrosis lung

Efficacy and Safety of Liposomal Clarithromycin and Its Effect on Pseudomonas aeruginosa Virulence Factors

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