-
International Journal of Antimicrobial... Sep 2012There has been growing interest in disrupting bacterial virulence mechanisms as a form of infectious disease control through the use of 'anti-infective' drugs....
There has been growing interest in disrupting bacterial virulence mechanisms as a form of infectious disease control through the use of 'anti-infective' drugs. Pseudomonas aeruginosa is an opportunistic pathogen noted for its intrinsic antibiotic resistance that causes serious infections requiring new therapeutic options. In this study, an analysis of the P. aeruginosa PAO1 deduced proteome was performed to identify pathogen-associated proteins. A computational screening approach was then used to discover drug repurposing opportunities, i.e. identifying approved drugs that bind and potentially disrupt the pathogen-associated protein targets. The selective oestrogen receptor modulator raloxifene, a drug currently used in the prevention of osteoporosis and/or invasive breast cancer in post-menopausal women, was predicted from this screen to bind P. aeruginosa PhzB2. PhzB2 is involved in production of the blue pigment pyocyanin produced via the phenazine biosynthesis pathway. Pyocyanin is toxic to eukaryotic cells and has been shown to play a role in infection in a mouse model, making it an attractive target for anti-infective drug discovery. Raloxifene was found to strongly attenuate P. aeruginosa virulence in a Caenorhabditis elegans model of infection. Treatment of P. aeruginosa wild-type strains PAO1 and PA14 with raloxifene resulted in a dose-dependent reduction in pyocyanin production in vitro; pyocyanin production and virulence were also reduced for a phzB2 insertion mutant. These results suggest that raloxifene may be suitable for further development as a therapeutic for P. aeruginosa infection and that such already approved drugs may be computationally screened and potentially repurposed as novel anti-infective/anti-virulence agents.
Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Caenorhabditis elegans; Proteome; Pseudomonas aeruginosa; Pyocyanine; Raloxifene Hydrochloride; Survival Analysis; Virulence; Virulence Factors
PubMed: 22819149
DOI: 10.1016/j.ijantimicag.2012.05.009 -
Applied and Environmental Microbiology Apr 2015Many bacteria convert bicyclic compounds, such as indole and naphthalene, to oxidized compounds, including hydroxyindoles and naphthols. Pseudomonas aeruginosa, a...
Many bacteria convert bicyclic compounds, such as indole and naphthalene, to oxidized compounds, including hydroxyindoles and naphthols. Pseudomonas aeruginosa, a ubiquitous bacterium that inhabits diverse environments, shows pathogenicity against animals, plants, and other microorganisms, and increasing evidence has shown that several bicyclic compounds alter the virulence-related phenotypes of P. aeruginosa. Here, we revealed that hydroxyindoles (4- and 5-hydroxyindoles) and naphthalene derivatives bearing hydroxyl groups specifically inhibit swarming motility but have minor effects on other motilities, including swimming and twitching, in P. aeruginosa. Further analyses using 1-naphthol showed that this effect is also associated with clinically isolated hyperswarming P. aeruginosa cells. Swarming motility is associated with the dispersion of cells from biofilms, and the addition of 1-naphthol maintained biofilm biomass without cell dispersion. We showed that this 1-naphthol-dependent swarming inhibition is independent of changes of rhamnolipid production and the intracellular level of signaling molecule cyclic-di-GMP (c-di-GMP). Transcriptome analyses revealed that 1-naphthol increases gene expression associated with multidrug efflux and represses gene expression associated with aerotaxis and with pyochelin, flagellar, and pilus synthesis. In the present study, we showed that several bicyclic compounds bearing hydroxyl groups inhibit the swarming motility of P. aeruginosa, and these results provide new insight into the chemical structures that inhibit the specific phenotypes of P. aeruginosa.
Topics: Gene Expression Profiling; Hydroxyl Radical; Indoles; Molecular Sequence Data; Naphthalenes; Pseudomonas aeruginosa; Sequence Analysis, DNA; Signal Transduction
PubMed: 25681177
DOI: 10.1128/AEM.04220-14 -
Journal of Infection in Developing... Oct 2015Pseudomonas aeruginosa is one of the most virulent nosocomial pathogens worldwide. Quorum sensing (QS) regulates the production of pathogenic virulence factors and...
INTRODUCTION
Pseudomonas aeruginosa is one of the most virulent nosocomial pathogens worldwide. Quorum sensing (QS) regulates the production of pathogenic virulence factors and biofilm formation in P. aeruginosa. The four genes lasR, lasI, rhlR,and rhlI were found to regulate this QS system. In this study, we aimed to assess the correlation between these four genes and QS-dependent virulence factors and to detect the inhibitory effect of clove oil on QS.
METHODOLOGY
Fifty P. aeruginosa clinical isolates were collected. Susceptibility to different antibiotics was tested. Virulence factors including biofilm formation, pyocyanin production, and twitching motility were phenotypically detected. QS genes were amplified by polymerase chain reaction (PCR), and one strain subsequently underwent sequencing. The inhibitory effect of clove oil on virulence factors was also tested.
RESULTS
A positive correlation was found between biofilm formation and the presence of lasR and rhlI genes. Twitching motility was positively correlated with the presence of lasR, lasI, and rhlI genes. On the other hand, no correlation was found between pyocyanin production and any of the studied genes. Only one isolate amplified all the tested QS gene primers, but it did not express any of the tested virulence factors phenotypically. Sequence analyses of this isolate showed that the four genes had point mutations.
CONCLUSIONS
Results emphasize the importance of QS in P. aeruginosa virulence; however, QS-deficient clinical isolates occur and are still capable of causing clinical infections in humans. Also, clove oil has an obvious inhibitory effect on QS, which should be clinically exploited.
Topics: Anti-Bacterial Agents; Biofilms; Clove Oil; Egypt; Humans; Locomotion; Microbial Sensitivity Tests; Pseudomonas Infections; Pseudomonas aeruginosa; Pyocyanine; Quorum Sensing; Virulence Factors
PubMed: 26517484
DOI: 10.3855/jidc.6492 -
Scientific Reports May 2016Pseudomonas aeruginosa is a Gram-negative bacterium of clinical significance. Although the genome of PAO1, a prototype strain of P. aeruginosa, has been extensively...
Pseudomonas aeruginosa is a Gram-negative bacterium of clinical significance. Although the genome of PAO1, a prototype strain of P. aeruginosa, has been extensively studied, approximately one-third of the functional genome remains unknown. With the emergence of antibiotic-resistant strains of P. aeruginosa, there is an urgent need to develop novel antibiotic and anti-virulence strategies, which may be facilitated by an approach that explores P. aeruginosa gene function in systems-level models. Here, we present a genome-wide functional network of P. aeruginosa genes, PseudomonasNet, which covers 98% of the coding genome, and a companion web server to generate functional hypotheses using various network-search algorithms. We demonstrate that PseudomonasNet-assisted predictions can effectively identify novel genes involved in virulence and antibiotic resistance. Moreover, an antibiotic-resistance network based on PseudomonasNet reveals that P. aeruginosa has common modular genetic organisations that confer increased or decreased resistance to diverse antibiotics, which accounts for the pervasiveness of cross-resistance across multiple drugs. The same network also suggests that P. aeruginosa has developed mechanism of trade-off in resistance across drugs by altering genetic interactions. Taken together, these results clearly demonstrate the usefulness of a genome-scale functional network to investigate pathogenic systems in P. aeruginosa.
Topics: Computational Biology; Drug Resistance, Bacterial; Gene Regulatory Networks; Genes, Bacterial; Pseudomonas aeruginosa; Systems Biology; Virulence Factors
PubMed: 27194047
DOI: 10.1038/srep26223 -
Frontiers in Bioscience (Landmark... Jan 2009The production of iron-scavenging siderophores by the opportunistic animal pathogen Pseudomonas aeruginosa is a textbook example of public goods cooperation. This trait... (Review)
Review
The production of iron-scavenging siderophores by the opportunistic animal pathogen Pseudomonas aeruginosa is a textbook example of public goods cooperation. This trait provides an excellent model system with which to study cooperation. Further, the links between siderophore production and P. aeruginosa virulence allow us to investigate how pathogen ecology, social behaviour and pathology might be connected. We present here the results of basic research on the evolution and ecology of siderophore cooperation in this species. In particular, we explore the effects of population and community structure, iron regime and genomic mutation rate on the relative success of siderophore cooperators and cheats. We also present preliminary data on the links between siderophore production and another clinically-relevant social trait, biofilm formation. It is our hope that more realistic laboratory studies of siderophore cooperation in P. aeruginosa will eventually cast light on the roles played by social traits in long-term microbial infections.
Topics: Pseudomonas aeruginosa; Siderophores; Virulence
PubMed: 19273338
DOI: 10.2741/3516 -
Bioresource Technology Jun 2011Pseudomonas aeruginosa produces abundant levels of rhamnolipid biosurfactants which exhibit remarkable chemical and physical characteristics, making these compounds... (Review)
Review
Pseudomonas aeruginosa produces abundant levels of rhamnolipid biosurfactants which exhibit remarkable chemical and physical characteristics, making these compounds attractive targets for biotechnology research. The complex gene regulation network involved in rhamnolipids' biosynthesis represents a challenge to industrial production, which has been the object of a growing number of studies. This article provides a comprehensive review of the known gene regulatory factors involved in rhamnolipid production within P. aeruginosa. The regulatory factors include quorum sensing systems proteins and environmental response, and global regulatory systems within basal bacterial physiology, acting either at transcriptional or post-transcriptional level. The multilayer gene regulation responds to a wide variety of environmental and physiologic signals, and is capable of combining different signals in unique and specific responses.
Topics: Gene Expression Regulation, Bacterial; Glycolipids; Pseudomonas aeruginosa; Transcription, Genetic
PubMed: 21498076
DOI: 10.1016/j.biortech.2011.03.074 -
Virulence Dec 2020Intracellular invasion is an advantageous mechanism used by pathogens to evade host defense and antimicrobial therapy. In patients, the intracellular microbial lifestyle...
Intracellular invasion is an advantageous mechanism used by pathogens to evade host defense and antimicrobial therapy. In patients, the intracellular microbial lifestyle can lead to infection persistence and recurrence, thus worsening outcomes. Lung infections caused by , especially in cystic fibrosis (CF) patients, are often aggravated by intracellular invasion and persistence of the pathogen. Proliferation of the infectious species relies on a continuous deoxyribonucleotide (dNTP) supply, for which the ribonucleotide reductase enzyme (RNR) is the unique provider. The large genome plasticity of and its ability to rapidly adapt to different environments are challenges for studying the pathophysiology associated with this type of infection. Using different reference strains and clinical isolates of independently combined with alveolar (A549) and bronchial (16HBE14o- and CF-CFBE41o-) epithelial cells, we analyzed host-pathogen interactions and intracellular bacterial persistence with the aim of determining a cell type-directed infection promoted by the strains. The oscillations in cellular toxicity and oxygen consumption promoted by the intracellular persistence of the strains were also analyzed among the different infectious lung models. Significantly, we identified class II RNR as the enzyme that supplies dNTPs to intracellular . This discovery could contribute to the development of RNR-targeted strategies against the chronicity occurring in this type of lung infection. Overall our study demonstrates that the choice of bacterial strain is critical to properly study the type of infectious process with relevant translational outcomes.
Topics: A549 Cells; Adaptation, Physiological; Bacterial Adhesion; Cell Line; Cystic Fibrosis; Cytoplasm; Epithelial Cells; Host-Pathogen Interactions; Humans; Lung; Pseudomonas Infections; Pseudomonas aeruginosa
PubMed: 32697923
DOI: 10.1080/21505594.2020.1787034 -
Ecotoxicology and Environmental Safety Dec 2020Pseudomonas aeruginosa is a small rod shaped Gram-negative bacterium of Gammaproteobacteria class known for its metabolic versatility. P. aeruginosa PFL-P1 was isolated...
Pseudomonas aeruginosa is a small rod shaped Gram-negative bacterium of Gammaproteobacteria class known for its metabolic versatility. P. aeruginosa PFL-P1 was isolated from Polycyclic Aromatic Hydrocarbons (PAHs) contaminated site of Paradip Port, Odisha Coast, India. The strain showed excellent biofilm formation and could retain its ability to form biofilm grown with different PAHs in monoculture as well as co-cultures. To explore mechanistic insights of PAHs metabolism, the whole genome of the strain was sequenced. Next generation sequencing unfolded a genome size of 6,333,060 bp encoding 5857 CDSs. Gene ontology distribution assigned to a total of 2862 genes, wherein 2235 genes were allocated to biological process, 1549 genes to cellular component and 2339 genes to molecular function. A total of 318 horizontally transferred genes were identified when the genome was compared with the reference genomes of P. aeruginosa PAO1 and P. aeruginosa DSM 50071. Further comparison of P. aeruginosa PFL-P1 genome with P. putida containing TOL plasmids revealed similarities in the meta cleavage pathway employed for degradation of aromatic compounds like xylene and toluene. Gene annotation and pathway analysis unveiled 145 genes involved in xenobiotic biodegradation and metabolism. The biofilm cultures of P. aeruginosa PFL-P1 could degrade ~74% phenanthrene within 120 h while degradation increased up to ~76% in co-culture condition. GC-MS analysis indicated presence of diverse metabolites indicating the involvement of multiple pathways for one of the PAHs (phenanthrene) degradation. The strain also possesses the genetic machinery to utilize diverse toxic aromatic compounds such as naphthalene, benzoate, aminobenzoate, fluorobenzoate, toluene, xylene, styrene, atrazine, caprolactam etc. Common catabolic gene clusters such as benABCD, xylXYZ and catAB were observed within the genome of P. aeruginosa PFL-P1 which play key roles in the degradation of various toxic aromatic compounds.
Topics: Bacterial Proteins; Biodegradation, Environmental; Biofilms; Genome, Bacterial; Marine Biology; Metabolic Networks and Pathways; Phenanthrenes; Plasmids; Polycyclic Aromatic Hydrocarbons; Pseudomonas aeruginosa
PubMed: 32871516
DOI: 10.1016/j.ecoenv.2020.111087 -
ACS Chemical Biology Feb 2019The interplay between the activities of lytic transglycosylases (LTs) and penicillin-binding proteins (PBPs) is critical for the health of the bacterial cell wall....
The interplay between the activities of lytic transglycosylases (LTs) and penicillin-binding proteins (PBPs) is critical for the health of the bacterial cell wall. Bulgecin A (a natural-product inhibitor of LTs) potentiates the activity of β-lactam antibiotics (inhibitors of PBPs), underscoring this intimate mechanistic interdependence. Bulgecin A in the presence of an appropriate β-lactam causes bulge deformation due to the formation of aberrant peptidoglycan at the division site of the bacterium. As Pseudomonas aeruginosa, a nefarious human pathogen, has 11 LT paralogs, the answer as to which LT activity correlates with β-lactam potentiation is important and is currently unknown. Growth of P. aeruginosa PAO1 strains harboring individual transposon-insertion mutants at each of the 11 genes for LTs, in the presence of the β-lactam antibiotic ceftazidime or meropenem, implicated the gene products of slt, mltD, and mltG (of the 11), in bulge formation and potentiation. Hence, the respective enzymes would be the targets of inhibition by bulgecin A, which was indeed documented. We further demonstrated by imaging in real time and by SEM that cell lysis occurs by the structural failure of this bulge. Upon removal of the β-lactam antibiotic prior to lysis, P. aeruginosa experiences delayed recovery from the elongation and bulge phenotype in the presence of bulgecin A. These observations argue for a collaborative role for the target LTs in the repair of the aberrant cell wall, the absence of activities of which in the presence of bulgecin A results in potentiation of the β-lactam antibiotic.
Topics: Acetylglucosamine; Anti-Bacterial Agents; Bacterial Proteins; Microbial Sensitivity Tests; Proline; Pseudomonas aeruginosa; beta-Lactams
PubMed: 30620575
DOI: 10.1021/acschembio.8b01025 -
Scientific Reports Dec 2019Microbial endocrinology has demonstrated for more than two decades, that eukaryotic substances (hormones, neurotransmitters, molecules of the immune system) can modulate...
Microbial endocrinology has demonstrated for more than two decades, that eukaryotic substances (hormones, neurotransmitters, molecules of the immune system) can modulate the physiological behavior of bacteria. Among them, the hormones/neurotransmitters, epinephrine (Epi) and norepinephrine (NE), released in case of stress, physical effort or used in medical treatment, were shown to be able to modify biofilm formation in various bacterial species. In the present study, we have evaluated the effect of Epi on motility, adhesion, biofilm formation and virulence of Pseudomonas aeruginosa, a bacterium linked to many hospital-acquired infections, and responsible for chronic infection in immunocompromised patients including persons suffering from cystic fibrosis. The results showed that Epi increased adhesion and biofilm formation of P. aeruginosa, as well as its virulence towards the Galleria mellonella larvae in vivo model. Deciphering the sensor of this molecule in P. aeruginosa and the molecular mechanisms involved may help to find new strategies of treatment to fight against this bacterium.
Topics: Bacterial Adhesion; Biofilms; Cell Line; Epinephrine; Humans; Pseudomonas aeruginosa; Virulence
PubMed: 31882963
DOI: 10.1038/s41598-019-56666-7