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Sample records for pseudomonas aeruginosa secretes

  1. Type VI Secretion System in Pseudomonas aeruginosa

    Science.gov (United States)

    Hachani, Abderrahman; Lossi, Nadine S.; Hamilton, Alexander; Jones, Cerith; Bleves, Sophie; Albesa-Jové, David; Filloux, Alain

    2011-01-01

    Pseudomonas aeruginosa is a Gram-negative bacterium causing chronic infections in cystic fibrosis patients. Such infections are associated with an active type VI secretion system (T6SS), which consists of about 15 conserved components, including the AAA+ ATPase, ClpV. The T6SS secretes two categories of proteins, VgrG and Hcp. Hcp is structurally similar to a phage tail tube component, whereas VgrG proteins show similarity to the puncturing device at the tip of the phage tube. In P. aeruginosa, three T6SSs are known. The expression of H1-T6SS genes is controlled by the RetS sensor. Here, 10 vgrG genes were identified in the PAO1 genome, among which three are co-regulated with H1-T6SS, namely vgrG1a/b/c. Whereas VgrG1a and VgrG1c were secreted in a ClpV1-dependent manner, secretion of VgrG1b was ClpV1-independent. We show that VgrG1a and VgrG1c form multimers, which confirmed the VgrG model predicting trimers similar to the tail spike. We demonstrate that Hcp1 secretion requires either VgrG1a or VgrG1c, which may act independently to puncture the bacterial envelope and give Hcp1 access to the surface. VgrG1b is not required for Hcp1 secretion. Thus, VgrG1b does not require H1-T6SS for secretion nor does H1-T6SS require VgrG1b for its function. Finally, we show that VgrG proteins are required for secretion of a genuine H1-T6SS substrate, Tse3. Our results demonstrate that VgrG proteins are not only secreted components but are essential for secretion of other T6SS substrates. Overall, we emphasize variability in behavior of three P. aeruginosa VgrGs, suggesting that, although very similar, distinct VgrGs achieve specific functions. PMID:21325275

  2. Characterization of Pseudomonas aeruginosa Chitinase, a Gradually Secreted Protein

    NARCIS (Netherlands)

    Folders, J. (Jindra); Algra, J. (Jon); Roelofs, M.S. (Marc); Loon, L.C. van; Tommassen, J.P.M.; Bitter, Wilbert

    2001-01-01

    The gram-negative bacterium Pseudomonas aeruginosa secretes many proteins into its extracellular environment via the type I, II, and III secretion systems. In this study, a gene, chiC, coding for an extracellular chitinolytic enzyme, was identified. The chiC gene encodes a polypeptide of 483 amino

  3. Secretion of elastinolytic enzymes and their propeptides by Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Braun, P; de Groot, A; Bitter, W; Tommassen, J

    Elastase of Pseudomonas aeruginosa is synthesized as a preproenzyme. The signal sequence is cleaved ol during transport across the inner membrane and, in the periplasm, proelastase is further processed. We demonstrate that the propeptide and the mature elastase are both secreted but that the

  4. Type VI Secretion System in Pseudomonas aeruginosa SECRETION AND MULTIMERIZATION OF VgrG PROTEINS

    NARCIS (Netherlands)

    Hachani, Abderrahman; Lossi, Nadine S.; Hamilton, Alexander; Jones, Cerith; Bleves, Sophie; Albesa-Jove, David; Filloux, Alain

    2011-01-01

    Pseudomonas aeruginosa is a Gram-negative bacterium causing chronic infections in cystic fibrosis patients. Such infections are associated with an active type VI secretion system (T6SS), which consists of about 15 conserved components, including the AAA(+) ATPase, ClpV. The T6SS secretes two

  5. Type VI secretion system in Pseudomonas aeruginosa: secretion and multimerization of VgrG proteins.

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    Hachani, Abderrahman; Lossi, Nadine S; Hamilton, Alexander; Jones, Cerith; Bleves, Sophie; Albesa-Jové, David; Filloux, Alain

    2011-04-08

    Pseudomonas aeruginosa is a Gram-negative bacterium causing chronic infections in cystic fibrosis patients. Such infections are associated with an active type VI secretion system (T6SS), which consists of about 15 conserved components, including the AAA+ ATPase, ClpV. The T6SS secretes two categories of proteins, VgrG and Hcp. Hcp is structurally similar to a phage tail tube component, whereas VgrG proteins show similarity to the puncturing device at the tip of the phage tube. In P. aeruginosa, three T6SSs are known. The expression of H1-T6SS genes is controlled by the RetS sensor. Here, 10 vgrG genes were identified in the PAO1 genome, among which three are co-regulated with H1-T6SS, namely vgrG1a/b/c. Whereas VgrG1a and VgrG1c were secreted in a ClpV1-dependent manner, secretion of VgrG1b was ClpV1-independent. We show that VgrG1a and VgrG1c form multimers, which confirmed the VgrG model predicting trimers similar to the tail spike. We demonstrate that Hcp1 secretion requires either VgrG1a or VgrG1c, which may act independently to puncture the bacterial envelope and give Hcp1 access to the surface. VgrG1b is not required for Hcp1 secretion. Thus, VgrG1b does not require H1-T6SS for secretion nor does H1-T6SS require VgrG1b for its function. Finally, we show that VgrG proteins are required for secretion of a genuine H1-T6SS substrate, Tse3. Our results demonstrate that VgrG proteins are not only secreted components but are essential for secretion of other T6SS substrates. Overall, we emphasize variability in behavior of three P. aeruginosa VgrGs, suggesting that, although very similar, distinct VgrGs achieve specific functions.

  6. Identification of a Chitin-Binding Protein Secreted by Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Folders, J. (Jindra); Tommassen, J.P.M.; Loon, L.C. van; Bitter, Wilbert

    1999-01-01

    One of the major proteins secreted by Pseudomonas aeruginosa is a 43-kDa protein, which is cleaved by elastase into smaller fragments, including a 30-kDa and a 23-kDa fragment. The N-terminal 23-kDa fragment was previously suggested as corresponding to a staphylolytic protease and was designated

  7. Chromosomal beta-lactamase is packaged into membrane vesicles and secreted from Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Ciofu, O; Beveridge, T J; Kadurugamuwa, J

    2000-01-01

    Membrane vesicles were isolated from one beta-lactam-sensitive and three beta-lactam-resistant Pseudomonas aeruginosa clinical isolates from patients with cystic fibrosis. The presence of the chromosomally encoded beta-lactamase in the membrane vesicles was shown by electron microscopy and enzyma...... and enzymatic studies. This is the first report of extracellular secretion of beta-lactamase in P. aeruginosa and it seems that the enzyme is packaged into membrane vesicles.......Membrane vesicles were isolated from one beta-lactam-sensitive and three beta-lactam-resistant Pseudomonas aeruginosa clinical isolates from patients with cystic fibrosis. The presence of the chromosomally encoded beta-lactamase in the membrane vesicles was shown by electron microscopy...

  8. Pseudomonas aeruginosa lipopolysaccharide induces CF-like alteration of protein secretion by human tracheal gland cells.

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    Kammouni, W; Figarella, C; Baeza, N; Marchand, S; Merten, M D

    1997-12-18

    Human tracheal gland (HTG) serous cells are now believed to play a major role in the physiopathology of cystic fibrosis. Because of the persistent inflammation and the specific infection by Pseudomonas aeruginosa in the lung, we looked for the action of the lipopolysaccharide (LPS) of this bacteria on human tracheal gland cells in culture by studying the secretion of the secretory leukocyte proteinase inhibitor (SLPI) which is a specific serous secretory marker of these cells. Treatment with Pseudomonas aeruginosa LPS resulted in a significant dose-dependent increase in the basal production of SLPI (+ 250 +/- 25%) whilst the SLPI transcript mRNA levels remained unchanged. This LPS-induced increase in secretion was inhibited by glucocorticoides. Furthermore, LPS treatment of HTG cells induces a loss of responsiveness to carbachol and isoproterenol but not to adenosine triphosphate. These findings indicate that HTG cells treated by Pseudomonas aeruginosa LPS have the same behavior as those previously observed with CF-HTG cells. Exploration by using reverse transcriptase polymerase chain reaction amplification showed that LPS downregulated cystic fibrosis transmembrane conductance regulator (CFTR) mRNA expression in HTG cells indicative of a link between CFTR function and consequent CF-like alteration in protein secretory process.

  9. Maggot excretions/secretions are differentially effective against biofilms of Staphylococcus aureus and Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    van der Plas, Mariena J A; Jukema, Gerrolt N; Wai, Sin-Wen

    2008-01-01

    OBJECTIVES: Lucilia sericata maggots are successfully used for treating chronic wounds. As the healing process in these wounds is complicated by bacteria, particularly when residing in biofilms that protect them from antibiotics and the immune system, we assessed the effects of maggot excretions....../secretions (ES) on Staphylococcus aureus and Pseudomonas aeruginosa biofilms, the clinically most relevant species. METHODS: We assessed the effects of ES on biofilms using microtitre plate assays, on bacterial viability using in vitro killing and radial diffusion assays, and on quorum sensing systems using...

  10. Excretions/secretions from bacteria-pretreated maggot are more effective against Pseudomonas aeruginosa biofilms.

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    Ke-chun Jiang

    Full Text Available BACKGROUND: Sterile larvae--maggots of the green bottle blowfly Lucilia sericata are employed as a treatment tool for various types of chronic wounds. Previous studies reported that excretions/secretions (ES of the sterile larvae could prevent and remove the biofilms of various species of bacteria. In the present study we assessed the effect of ES from the larvae pretreated with Pseudomonas aeruginosa on the bacteria biofilms. METHODS AND FINDINGS: We investigated the effects of ES from the maggot pretreated with P. aeruginosa on the biofilms using microtitre plate assays and on bactericidal effect using the colony-forming unit (CFU assay. The results showed that only 30 µg of the ES from the pretreated maggots could prevent and degrade the biofilm of P. aeruginosa. However, the CFU count of P. aeruginosa was not decrease when compared to the ES from non pretreated maggots in this study condition. It is suggested that the ES from the pretreated maggot was more effective against biofilm of P. aeruginosa than sterile maggot ES. CONCLUSIONS: Our results showed that the maggot ES, especially the bacteria-pretreated larva ES may provide a new insight into the treatment tool of the bacterial biofilms.

  11. Diversity of virulence phenotypes among type III secretion negative Pseudomonas aeruginosa clinical isolates.

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    Jonida Toska

    Full Text Available Pseudomonas aeruginosa is a frequent cause of acute infections. The primary virulence factor that has been linked to clinical disease is the type III secretion system, a molecular syringe that delivers effector proteins directly into host cells. Despite the importance of type III secretion in dictating clinical outcomes and promoting disease in animal models of infections, clinical isolates often do not express the type III secretion system in vitro. Here we screened 81 clinical P. aeruginosa isolates for secretion of type III secretion system substrates by western blot. Non-expressing strains were also subjected to a functional test assaying the ability to intoxicate epithelial cells in vitro, and to survive and cause disease in a murine model of corneal infection. 26 of 81 clinical isolates were found to be type III secretion negative by western blot. 17 of these 26 non-expressing strains were tested for their ability to cause epithelial cell rounding. Of these, three isolates caused epithelial cell rounding in a type III secretion system dependent manner, and one strain was cytotoxic in a T3SS-independent manner. Five T3SS-negative isolates were also tested for their ability to cause disease in a murine model of corneal infection. Of these isolates, two strains caused severe corneal disease in a T3SS-independent manner. Interestingly, one of these strains caused significant disease (inflammation despite being cleared. Our data therefore show that P. aeruginosa clinical isolates can cause disease in a T3SS-independent manner, demonstrating the existence of novel modifiers of clinical disease.

  12. Pseudomonas aeruginosa in Healthcare Settings

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    ... Sepsis Sharps Safety - CDC Transplant Safety Vaccine Safety Pseudomonas aeruginosa in Healthcare Settings Recommend on Facebook Tweet Share ... aeruginosa . Pseudomonas aeruginosa What types of infections does Pseudomonas aeruginosa cause? Serious Pseudomonas infections usually occur in people ...

  13. Subinhibitory concentration of kanamycin induces the Pseudomonas aeruginosa type VI secretion system.

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    Cerith Jones

    Full Text Available Pseudomonas aeruginosa is a Gram-negative bacterium found in natural environments including plants, soils and warm moist surfaces. This organism is also in the top ten of nosocomial pathogens, and prevalent in cystic fibrosis (CF lung infections. The ability of P. aeruginosa to colonize a wide variety of environments in a lasting manner is associated with the formation of a resistant biofilm and the capacity to efficiently outcompete other microorganisms. Here we demonstrate that sub-inhibitory concentration of kanamycin not only induces biofilm formation but also induces expression of the type VI secretion genes in the H1-T6SS cluster. The H1-T6SS is known for its role in toxin production and bacterial competition. We show that the antibiotic induction of the H1-T6SS only occurs when a functional Gac/Rsm pathway is present. These observations may contribute to understand how P. aeruginosa responds to antibiotic producing competitors. It also suggests that improper antibiotic therapy may enhance P. aeruginosa colonization, including in the airways of CF patients.

  14. Plant flavones enhance antimicrobial activity of respiratory epithelial cell secretions against Pseudomonas aeruginosa.

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    Benjamin M Hariri

    Full Text Available Flavones are a class of natural plant secondary metabolites that have anti-inflammatory and anti-bacterial effects. Some flavones also activate the T2R14 bitter taste receptor, which is expressed in motile cilia of the sinonasal epithelium and activates innate immune nitric oxide (NO production. Flavones may thus be potential therapeutics for respiratory infections. Our objective was to examine the anti-microbial effects of flavones on the common sinonasal pathogens Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa, evaluating both planktonic and biofilm growth. Flavones had only very low-level antibacterial activity alone. They did not reduce biofilm formation, but did reduce production of the important P. aeruginosa inflammatory mediator and ciliotoxin pyocyanin. However, flavones exhibited synergy against P. aeruginosa in the presence of antibiotics or recombinant human lysozyme. They also enhanced the efficacy of antimicrobials secreted by cultured and primary human airway cells grown at air-liquid interface. This suggests that flavones may have anti-gram-negative potential as topical therapeutics when combined with antibiotics or in the context of innate antimicrobials secreted by the respiratory or other epithelia. This may have an additive effect when combined with T2R14-activated NO production. Additional studies are necessary to understand which flavone compounds or mixtures are the most efficacious.

  15. Protein secretion systems in Pseudomonas aeruginosa: an essay on diversity, evolution and function

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    Alain eFILLOUX

    2011-07-01

    Full Text Available Protein secretion systems are molecular nanomachines used by Gram-negative bacteria to thrive within their environment. They are used to release enzymes that hydrolyze complex carbon sources into usable compounds, or to release proteins that capture essential ions such as iron. They are also used to colonize and survive within eukaryotic hosts, causing acute or chronic infections, subverting the host cell response and escaping the immune system. In this article, the opportunistic human pathogen Pseudomonas aeruginosa is used as a model to review the diversity of secretion systems that bacteria have evolved to achieve these goals. This diversity may result from a progressive transformation of cell envelope complexes that initially may not have been dedicated to secretion. The striking similarities between secretion systems and type IV pili, flagella, bacteriophage tail or efflux pumps is a nice illustration of this evolution. Differences are also needed since various secretion configurations calls for diversity. For example, some proteins are released in the extracellular medium while others are directly injected into the cytosol of eukaryotic cells. Some proteins are folded before being released and transit into the periplasm. Other proteins cross the whole cell envelope at once in an unfolded state. However, the secretion system requires conserved basic elements or features. For example, there is a need for an energy source or for an outer membrane channel. The structure of this review is thus quite unconventional. Instead of listing secretion types one after each other, it presents a melting pot of concepts indicating that secretion types are in constant evolution and use basic principles. In other words, emergence of new secretion systems could be predicted the way Mendeleïev had anticipated characteristics of yet unknown elements.

  16. Characterization of a novel two-partner secretion system implicated in the virulence of Pseudomonas aeruginosa.

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    Faure, Laura M; Garvis, Steve; de Bentzmann, Sophie; Bigot, Sarah

    2014-09-01

    Pseudomonas aeruginosa is an opportunistic human pathogen implicated in nosocomial infection and infecting people with compromised immune systems such as cystic fibrosis patients. Although multiple genes involved in P. aeruginosa pathogenesis have been characterized, the overall mechanism of virulence is not fully understood. In this study, we identified a functional two-partner secretion (TPS) system, composed of the PdtA exoprotein and its cognate pore-forming β-barrel PdtB transporter, which is implicated in the virulence of P. aeruginosa. We found that the predicted PdtA exoprotein is related to the HMW-like adhesins subfamily TPS systems. We demonstrate here that limitation of inorganic phosphate (Pi) allows the production of PdtA protein. We show that PdtA is processed during its outer-membrane translocation, with an N-terminal domain released into the extracellular environment and a C-terminal domain associated with the outer membrane of the cell. We also obtained evidence that the transport of PdtA is strictly dependent on the production of PdtB, a result confirming that these proteins constitute a functional TPS system. Furthermore, using the Caenorhabditis elegans model of infection, we show that a pdtA mutant is less virulent than the wild-type strain. © 2014 The Authors.

  17. A Pseudomonas aeruginosa type VI secretion phospholipase D effector targets both prokaryotic and eukaryotic cells.

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    Jiang, Feng; Waterfield, Nicholas R; Yang, Jian; Yang, Guowei; Jin, Qi

    2014-05-14

    Widely found in animal and plant-associated proteobacteria, type VI secretion systems (T6SSs) are potentially capable of facilitating diverse interactions with eukaryotes and/or other bacteria. Pseudomonas aeruginosa encodes three distinct T6SS haemolysin coregulated protein (Hcp) secretion islands (H1, H2, and H3-T6SS), each involved in different aspects of the bacterium's interaction with other organisms. Here we describe the characterization of a P. aeruginosa H3-T6SS-dependent phospholipase D effector, PldB, and its three tightly linked cognate immunity proteins. PldB targets the periplasm of prokaryotic cells and exerts an antibacterial activity. Surprisingly, PldB also facilitates intracellular invasion of host eukaryotic cells by activation of the PI3K/Akt pathway, revealing it to be a trans-kingdom effector. Our findings imply a potentially widespread T6SS-mediated mechanism, which deploys a single phospholipase effector to influence both prokaryotic cells and eukaryotic hosts. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Biofilms and type III secretion are not mutually exclusive in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Mikkelsen, H; Bond, N J; Skindersoe, M E

    2009-01-01

    Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes acute and chronic infections in immunocompromised individuals. It is also a model organism for bacterial biofilm formation. Acute infections are often associated with planktonic or free-floating cells, high virulence...... and fast growth. Conversely, chronic infections are often associated with the biofilm mode of growth, low virulence and slow growth that resembles that of planktonic cells in stationary phase. Biofilm formation and type III secretion have been shown to be reciprocally regulated, and it has been suggested...... that factors related to acute infection may be incompatible with biofilm formation. In a previous proteomic study of the interrelationships between planktonic cells, colonies and continuously grown biofilms, we showed that biofilms under the growth conditions applied are more similar to planktonic cells...

  19. Oligoribonuclease is required for the type III secretion system and pathogenesis of Pseudomonas aeruginosa.

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    Chen, Gukui; Zhao, Qiang; Zhu, Feng; Chen, Ronghao; Jin, Yongxin; Liu, Chang; Pan, Xiaolei; Jin, Shouguang; Wu, Weihui; Cheng, Zhihui

    2016-01-01

    Oligoribonuclease (Orn) is a 3' to 5' exonuclease that degrades nanoRNAs, which can serve as primers for transcription initiation at a significant fraction of promoters. One of Orn's substrates, pGpG inhibits the enzymatic activity of EAL-domain containing phosphodiesterases (PDEs), thereby increasing intracellular cyclic-di-GMP (c-di-GMP) level. Here, we found that an orn mutant of Pseudomonas aeruginosa displayed reduced cytotoxicity, which was mainly due to deficient type III secretion system (T3SS). Given the importance of T3SS in pathogenicity, we examined the bacterial virulence in a mouse acute pneumonia model and found that the Δorn mutant was highly attenuated compared to the wild type PA14 strain. Overexpression of an EAL domain-containing PDE reduced the c-di-GMP level as well as biofilm formation in the Δorn mutant. However, no effect was observed on the expression of T3SS genes, suggesting that increased c-di-GMP level is not the solely cause of defective T3SS in the Δorn mutant. Overall, our results demonstrated an essential role of Orn in the expression of T3SS as well as pathogenesis of P. aeruginosa. Copyright © 2016 Elsevier GmbH. All rights reserved.

  20. Cheating by type 3 secretion system-negative Pseudomonas aeruginosa during pulmonary infection.

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    Czechowska, Kamila; McKeithen-Mead, Saria; Al Moussawi, Khatoun; Kazmierczak, Barbara I

    2014-05-27

    The opportunistic pathogen Pseudomonas aeruginosa expresses a type 3 secretion system (T3SS) strongly associated with bacterial virulence in murine models and human patients. T3SS effectors target host innate immune mechanisms, and T3SS-defective mutants are cleared more efficiently than T3SS-positive bacteria by an immunocompetent host. Nonetheless, T3SS-negative isolates are recovered from many patients with documented P. aeruginosa infections, leading us to test whether T3SS-negative strains could have a selective advantage during in vivo infection. Mice were infected with mixtures of T3SS-positive WT P. aeruginosa plus isogenic T3SS-OFF or constitutively T3SS-ON mutants. Relative fitness of bacteria in this acute pneumonia model was reflected by the competitive index of mutants relative to WT. T3SS-OFF strains outcompeted WT PA103 in vivo, whereas a T3SS-ON mutant showed decreased fitness compared with WT. In vitro growth rates of WT and T3SS-OFF bacteria were determined under T3SS-inducing conditions and did not differ significantly. Increased fitness of T3SS-OFF bacteria was no longer observed at high ratios of T3SS-OFF to WT, a feature characteristic of bacterial cheaters. Cheating by T3SS-OFF bacteria occurred only when T3SS-positive bacteria expressed the phospholipase A2 effector Exotoxin U (ExoU). T3SS-OFF bacteria showed no fitness advantage in competition experiments carried out in immunodeficient MyD88-knockout mice or in neutrophil-depleted animals. Our findings indicate that T3SS-negative isolates benefit from the public good provided by ExoU-mediated killing of recruited innate immune cells. Whether this transient increase in fitness observed for T3SS-negative strains in mice contributes to the observed persistence of T3SS-negative isolates in humans is of ongoing interest.

  1. Development of loop-mediated isothermal amplification assays for genotyping of Type III Secretion System in Pseudomonas aeruginosa.

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    Shi, H; Chen, Z; Kan, J

    2015-10-01

    Pseudomonas aeruginosa is a well-known environmental bacterium capable of causing a variety of life-threatening human infections, with a Type III Secretion System (T3SS) as the most significant virulence determinant. P. aeruginosa strains exhibit unique T3SS virulence genotypes defined by the presence of either exoS or exoU. In this study, loop-mediated isothermal amplification (LAMP) assays for rapid detection of exoS and exoU in P. aeruginosa have been developed and evaluated. Set of four primers were designed for LAMP-based amplification of exoS and exoU respectively. The LAMP reactions were performed at 63°C for 40 min, with detection limits of 100 fg purified DNA. In 107 river water isolates, exoS and exoU were detected in 10 (9%) and 89 (83%) isolates, respectively, and in 38 soil isolates, they were detected in 7 (18%) and 31 (82%) cases respectively. In conclusion, the LAMP assays are rapid, simple and cost-effective tools for detection of the exoU- and exoS-types of P. aeruginosa strains. This method can be used for the rapid, sensitive and low-cost detection of genes (exoS and exoU) encoding proteins that are part of Type III Secretion System of Pseudomonas aeruginosa. It can serve as an efficient method in outbreak situations or in routine surveillance studies to judge virulence potential and to investigate pathogenesis of P. aeruginosa. © 2015 The Society for Applied Microbiology.

  2. Nuclear Magnetic Resonance Characterization of the Type III Secretion System Tip Chaperone Protein PcrG of Pseudomonas aeruginosa.

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    Chaudhury, Sukanya; Nordhues, Bryce A; Kaur, Kawaljit; Zhang, Na; De Guzman, Roberto N

    2015-11-03

    Lung infection with Pseudomonas aeruginosa is the leading cause of death among cystic fibrosis patients. To initiate infection, P. aeruginosa assembles a protein nanomachine, the type III secretion system (T3SS), to inject bacterial proteins directly into target host cells. An important regulator of the P. aeruginosa T3SS is the chaperone protein PcrG, which forms a complex with the tip protein, PcrV. In addition to its role as a chaperone to the tip protein, PcrG also regulates protein secretion. PcrG homologues are also important in the T3SS of other pathogens such as Yersinia pestis, the causative agent of bubonic plague. The atomic structure of PcrG or any member of the family of tip protein chaperones is currently unknown. Here, we show by circular dichroism and nuclear magnetic resonance (NMR) spectroscopy that PcrG lacks a tertiary structure. However, it is not completely disordered but contains secondary structures dominated by two long α-helices from residue 16 to 41 and from residue 55 to 76. The helices of PcrG are partially formed, have similar backbone dynamics, and are flexible. NMR titrations show that the entire length of PcrG residues from position 9 to 76 is involved in binding to PcrV. PcrG adds to the growing list of partially folded or unstructured proteins with important roles in type III secretion.

  3. Purification, crystallization and preliminary X-ray diffraction analysis of Cif, a virulence factor secreted by Pseudomonas aeruginosa.

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    Bahl, Christopher D; MacEachran, Daniel P; O'Toole, George A; Madden, Dean R

    2010-01-01

    The opportunistic pathogen Pseudomonas aeruginosa secretes a protein that triggers the accelerated degradation of the cystic fibrosis transmembrane conductance regulator (CFTR) in airway epithelial cells. This protein, which is known as the CFTR inhibitory factor (Cif), acts as a virulence factor and may facilitate airway colonization by P. aeruginosa. Based on sequence similarity Cif appears to be an epoxide hydrolase (EH), but it lacks several of the conserved features found in the active sites of canonical members of the EH family. Here, the crystallization of purified recombinant Cif by vapor diffusion is reported. The crystals formed in space group C2, with unit-cell parameters a = 167.4, b = 83.6, c = 88.3 A, beta = 100.6 degrees . The crystals diffracted to 2.39 A resolution on a rotating-anode source. Based on the calculated Matthews coefficient (2.2 A(3) Da(-1)), it appears that the asymmetric unit contains four molecules.

  4. An epoxide hydrolase secreted by Pseudomonas aeruginosa decreases mucociliary transport and hinders bacterial clearance from the lung.

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    Hvorecny, Kelli L; Dolben, Emily; Moreau-Marquis, Sophie; Hampton, Thomas H; Shabaneh, Tamer B; Flitter, Becca A; Bahl, Christopher D; Bomberger, Jennifer M; Levy, Bruce D; Stanton, Bruce A; Hogan, Deborah A; Madden, Dean R

    2018-01-01

    The opportunistic pathogen Pseudomonas aeruginosa colonizes the lungs of susceptible individuals by deploying virulence factors targeting host defenses. The secreted factor Cif (cystic fibrosis transmembrane conductance regulator inhibitory factor) dysregulates the endocytic recycling of CFTR and thus reduces CFTR abundance in host epithelial membranes. We have postulated that the decrease in ion secretion mediated by Cif would slow mucociliary transport and decrease bacterial clearance from the lungs. To test this hypothesis, we explored the effects of Cif in cultured epithelia and in the lungs of mice. We developed a strategy to interpret the "hurricane-like" motions observed in reconstituted cultures and identified a Cif-mediated decrease in the velocity of mucus transport in vitro. Presence of Cif also increased the number of bacteria recovered at two time points in an acute mouse model of pneumonia caused by P. aeruginosa. Furthermore, recent work has demonstrated an inverse correlation between the airway concentrations of Cif and 15-epi-lipoxin A4, a proresolving lipid mediator important in host defense and the resolution of pathogen-initiated inflammation. Here, we observe elevated levels of 15-epi-lipoxin A4 in the lungs of mice infected with a strain of P. aeruginosa that expresses only an inactive form of cif compared with those mice infected with wild-type P. aeruginosa. Together these data support the inclusion of Cif on the list of virulence factors that assist P. aeruginosa in colonizing and damaging the airways of compromised patients. Furthermore, this study establishes techniques that enable our groups to explore the underlying mechanisms of Cif effects during respiratory infection.

  5. Evaluation of biofilm production and characterization of genes encoding type III secretion system among Pseudomonas aeruginosa isolated from burn patients.

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    Jabalameli, Fereshteh; Mirsalehian, Akbar; Khoramian, Babak; Aligholi, Marzieh; Khoramrooz, Seyed Sajjad; Asadollahi, Parisa; Taherikalani, Morovat; Emaneini, Mohammad

    2012-12-01

    Pseudomonas aeruginosa is one of the common pathogenic causes of serious infections in burn patients throughout the world. Type III secretion toxins are thought to promote the dissemination of P. aeruginosa from the site of infection, the bacterial evasion of the host immune response and inhibition of DNA synthesis leading to host cell death. A total of 96 isolates of P. aeruginosa were collected from wound infections of burn patients, from April to July 2010. Antimicrobial susceptibility of the isolates were determined by disk agar diffusion method. Polymerase chain reaction (PCR)-based method was used for targeting the genes encoding the type III secretion toxins. The quantitative determination of biofilm-forming capacity was determined by a colorimetric microtiter plate assay. All the isolates were resistant to cefixime and ceftriaxone. More than 90% of the isolates were resistant to amikacin, carbenicillin, cefepime, cefotaxime, cefpodoxime, gatifloxacin, gentamicin, piperacillin/tazobactam, ticarcillin and tobramycin. All the isolates carried the exoT gene, 95% carried exoY, 64.5% carried exoU and 29% carried the exoS gene. Most of the isolates (58%) carried both exoY and exoU genes while 24% showed the concomitant presence of exoS and exoY and 1% carried both exoS and exoU. Coexistence of exoS, exoY and exoU was seen in 4% of the isolates. Biofilm formation was seen in more than 96% of the isolates among which 47% were strong biofilm producers, 26% were moderate and 22.9% were weak biofilm formers. In conclusion, the findings of this study show that the genes, particularly the exoU gene, encoding the type III secretion toxins, are commonly disseminated among the P. aeruginosa strains isolated from burn patients. Copyright © 2012 Elsevier Ltd and ISBI. All rights reserved.

  6. Cellular Effects of Pyocyanin, a Secreted Virulence Factor of Pseudomonas aeruginosa

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    Susan Hall

    2016-08-01

    Full Text Available Pyocyanin has recently emerged as an important virulence factor produced by Pseudomonas aeruginosa. The redox-active tricyclic zwitterion has been shown to have a number of potential effects on various organ systems in vitro, including the respiratory, cardiovascular, urological, and central nervous systems. It has been shown that a large number of the effects to these systems are via the formation of reactive oxygen species. The limitations of studies are, to date, focused on the localized effect of the release of pyocyanin (PCN. It has been postulated that, given its chemical properties, PCN is able to readily cross biological membranes, however studies have yet to be undertaken to evaluate this effect. This review highlights the possible manifestations of PCN exposure; however, most studies to date are in vitro. Further high quality in vivo studies are needed to fully assess the physiological manifestations of PCN exposure on the various body systems.

  7. Cellular Effects of Pyocyanin, a Secreted Virulence Factor of Pseudomonas aeruginosa.

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    Hall, Susan; McDermott, Catherine; Anoopkumar-Dukie, Shailendra; McFarland, Amelia J; Forbes, Amanda; Perkins, Anthony V; Davey, Andrew K; Chess-Williams, Russ; Kiefel, Milton J; Arora, Devinder; Grant, Gary D

    2016-08-09

    Pyocyanin has recently emerged as an important virulence factor produced by Pseudomonas aeruginosa. The redox-active tricyclic zwitterion has been shown to have a number of potential effects on various organ systems in vitro, including the respiratory, cardiovascular, urological, and central nervous systems. It has been shown that a large number of the effects to these systems are via the formation of reactive oxygen species. The limitations of studies are, to date, focused on the localized effect of the release of pyocyanin (PCN). It has been postulated that, given its chemical properties, PCN is able to readily cross biological membranes, however studies have yet to be undertaken to evaluate this effect. This review highlights the possible manifestations of PCN exposure; however, most studies to date are in vitro. Further high quality in vivo studies are needed to fully assess the physiological manifestations of PCN exposure on the various body systems.

  8. Pseudomonas aeruginosa uses type III secretion system to kill biofilm-associated amoebae

    DEFF Research Database (Denmark)

    Matz, Carsten; Moreno, Ana Maria; Alhede, Morten

    2008-01-01

    and killed biofilm-associated amoebae by a quorum-sensing independent mechanism. Analysis of the amoeba-induced transcriptome indicated the involvement of the P. aeruginosa type III secretion system (T3SS) in this interaction. A comparison of mutants with specific defects in the T3SS demonstrated the use...... of the secretion apparatus and the effectors ExoU, ExoS and ExoT in the killing process, of which ExoU had the greatest impact. T3SS-mediated virulence towards A. castellanii was found to be controlled by the global regulators RpoN and RpoS and through modulation of cAMP and alginate biosynthesis. Our findings...

  9. High-resolution time series of Pseudomonas aeruginosa gene expression and rhamnolipid secretion through growth curve synchronization

    Directory of Open Access Journals (Sweden)

    Xavier João B

    2011-06-01

    Full Text Available Abstract Background Online spectrophotometric measurements allow monitoring dynamic biological processes with high-time resolution. Contrastingly, numerous other methods require laborious treatment of samples and can only be carried out offline. Integrating both types of measurement would allow analyzing biological processes more comprehensively. A typical example of this problem is acquiring quantitative data on rhamnolipid secretion by the opportunistic pathogen Pseudomonas aeruginosa. P. aeruginosa cell growth can be measured by optical density (OD600 and gene expression can be measured using reporter fusions with a fluorescent protein, allowing high time resolution monitoring. However, measuring the secreted rhamnolipid biosurfactants requires laborious sample processing, which makes this an offline measurement. Results Here, we propose a method to integrate growth curve data with endpoint measurements of secreted metabolites that is inspired by a model of exponential cell growth. If serial diluting an inoculum gives reproducible time series shifted in time, then time series of endpoint measurements can be reconstructed using calculated time shifts between dilutions. We illustrate the method using measured rhamnolipid secretion by P. aeruginosa as endpoint measurements and we integrate these measurements with high-resolution growth curves measured by OD600 and expression of rhamnolipid synthesis genes monitored using a reporter fusion. Two-fold serial dilution allowed integrating rhamnolipid measurements at a ~0.4 h-1 frequency with high-time resolved data measured at a 6 h-1 frequency. We show how this simple method can be used in combination with mutants lacking specific genes in the rhamnolipid synthesis or quorum sensing regulation to acquire rich dynamic data on P. aeruginosa virulence regulation. Additionally, the linear relation between the ratio of inocula and the time-shift between curves produces high-precision measurements of

  10. Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Maria; Bjarnsholt, Thomas; Givskov, Michael

    2014-01-01

    The opportunistic gram-negative bacterium Pseudomonas aeruginosa is implicated in many chronic infections and is readily isolated from chronic wounds, medical devices, and the lungs of cystic fibrosis patients. P. aeruginosa is believed to persist in the host organism due to its capacity to form...... biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling...

  11. A conformational landscape for alginate secretion across the outer membrane of Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Jingquan [Trinity College, Dublin (Ireland); Rouse, Sarah L. [University of Oxford, South Parks Road, Oxford (United Kingdom); Li, Dianfan; Pye, Valerie E.; Vogeley, Lutz; Brinth, Alette R.; El Arnaout, Toufic [Trinity College, Dublin (Ireland); Whitney, John C.; Howell, P. Lynne [The Hospital for Sick Children, Toronto, Ontario (Canada); University of Toronto, Toronto, Ontario (Canada); Sansom, Mark S. P. [University of Oxford, South Parks Road, Oxford (United Kingdom); Caffrey, Martin, E-mail: martin.caffrey@tcd.ie [Trinity College, Dublin (Ireland)

    2014-08-01

    Crystal structures of the β-barrel porin AlgE reveal a mechanism whereby alginate is exported from P. aeruginosa for biofilm formation. The exopolysaccharide alginate is an important component of biofilms produced by Pseudomonas aeruginosa, a major pathogen that contributes to the demise of cystic fibrosis patients. Alginate exits the cell via the outer membrane porin AlgE. X-ray structures of several AlgE crystal forms are reported here. Whilst all share a common β-barrel constitution, they differ in the degree to which loops L2 and T8 are ordered. L2 and T8 have been identified as an extracellular gate (E-gate) and a periplasmic gate (P-gate), respectively, that reside on either side of an alginate-selectivity pore located midway through AlgE. Passage of alginate across the membrane is proposed to be regulated by the sequential opening and closing of the two gates. In one crystal form, the selectivity pore contains a bound citrate. Because citrate mimics the uronate monomers of alginate, its location is taken to highlight a route through AlgE taken by alginate as it crosses the pore. Docking and molecular-dynamics simulations support and extend the proposed transport mechanism. Specifically, the P-gate and E-gate are flexible and move between open and closed states. Citrate can leave the selectivity pore bidirectionally. Alginate docks stably in a linear conformation through the open pore. To translate across the pore, a force is required that presumably is provided by the alginate-synthesis machinery. Accessing the open pore is facilitated by complex formation between AlgE and the periplasmic protein AlgK. Alginate can thread through a continuous pore in the complex, suggesting that AlgK pre-orients newly synthesized exopolysaccharide for delivery to AlgE.

  12. Population Structure of Pseudomonas aeruginosa

    National Research Council Canada - National Science Library

    Lutz Wiehlmann; Gerd Wagner; Nina Cramer; Benny Siebert; Peter Gudowius; Gracia Morales; Thilo Köhler; Christian van Delden; Christian Weinel; Peter Slickers; Burkhard Tümmler

    2007-01-01

    The metabolically versatile Gram-negative bacterium Pseudomonas aeruginosa inhabits terrestrial, aquatic, animal-, human-, and plant-host-associated environments and is an important causative agent...

  13. Purification, Crystallization and Preliminary X-ray Diffraction Analysis of Cif, a Virulence Factor Secreted by Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Bahl, C.; MacEachran, D; O& apos; Toole, G; Madden, D

    2010-01-01

    The opportunistic pathogen Pseudomonas aeruginosa secretes a protein that triggers the accelerated degradation of the cystic fibrosis transmembrane conductance regulator (CFTR) in airway epithelial cells. This protein, which is known as the CFTR inhibitory factor (Cif), acts as a virulence factor and may facilitate airway colonization by P. aeruginosa. Based on sequence similarity Cif appears to be an epoxide hydrolase (EH), but it lacks several of the conserved features found in the active sites of canonical members of the EH family. Here, the crystallization of purified recombinant Cif by vapor diffusion is reported. The crystals formed in space group C2, with unit-cell parameters a = 167.4, b = 83.6, c = 88.3 {angstrom}, {beta} = 100.6{sup o}. The crystals diffracted to 2.39 {angstrom} resolution on a rotating-anode source. Based on the calculated Matthews coefficient (2.2 {angstrom}{sup 3} Da{sup -1}), it appears that the asymmetric unit contains four molecules.

  14. Examining the Role of Actin-Plasma Membrane Association in Pseudomonas aeruginosa Infection and Type III Secretion Translocation in Migratory T24 Epithelial Cells

    Science.gov (United States)

    Bridge, Dacie R.; Martin, Karen H.; Moore, Elizabeth R.; Lee, Wendy M.; Carroll, James A.; Rocha, Claudia L.

    2012-01-01

    The opportunistic pathogen Pseudomonas aeruginosa targets wounded epithelial barriers, but the cellular alteration that increases susceptibility to P. aeruginosa infection remains unclear. This study examined how cell migration contributes to the establishment of P. aeruginosa infections using (i) highly migratory T24 epithelial cells as a cell culture model, (ii) mutations in the type III secretion (T3S) effector ExoS to manipulate P. aeruginosa infection, and (iii) high-resolution immunofluorescent microscopy to monitor ExoS translocation. ExoS includes both GTPase-activating (GAP) and ADP-ribosyltransferase (ADPRT) activities, and P. aeruginosa cells expressing wild-type ExoS preferentially bound to the leading edge of T24 cells, where ExoS altered leading-edge architecture and actin anchoring in conjunction with interrupting T3S translocation. Inactivation of ExoS GAP activity allowed P. aeruginosa to be internalized and secrete ExoS within T24 cells, but as with wild-type ExoS, translocation was limited in association with disruption of actin anchoring. Inactivation of ExoS ADPRT activity resulted in significantly enhanced T3S translocation by P. aeruginosa cells that remained extracellular and in conjunction with maintenance of actin-plasma membrane association. Infection with P. aeruginosa expressing ExoS lacking both GAP and ADPRT activities resulted in the highest level of T3S translocation, and this occurred in conjunction with the entry and alignment of P. aeruginosa and ExoS along actin filaments. Collectively, in using ExoS mutants to modulate and visualize T3S translocation, we were able to (i) confirm effector secretion by internalized P. aeruginosa, (ii) differentiate the mechanisms underlying the effects of ExoS GAP and ADPRT activities on P. aeruginosa internalization and T3S translocation, (iii) confirm that ExoS ADPRT activity targeted a cellular substrate that interrupted T3S translocation, (iv) visualize the ability of P. aeruginosa and Exo

  15. Examining the role of actin-plasma membrane association in Pseudomonas aeruginosa infection and type III secretion translocation in migratory T24 epithelial cells.

    Science.gov (United States)

    Bridge, Dacie R; Martin, Karen H; Moore, Elizabeth R; Lee, Wendy M; Carroll, James A; Rocha, Claudia L; Olson, Joan C

    2012-09-01

    The opportunistic pathogen Pseudomonas aeruginosa targets wounded epithelial barriers, but the cellular alteration that increases susceptibility to P. aeruginosa infection remains unclear. This study examined how cell migration contributes to the establishment of P. aeruginosa infections using (i) highly migratory T24 epithelial cells as a cell culture model, (ii) mutations in the type III secretion (T3S) effector ExoS to manipulate P. aeruginosa infection, and (iii) high-resolution immunofluorescent microscopy to monitor ExoS translocation. ExoS includes both GTPase-activating (GAP) and ADP-ribosyltransferase (ADPRT) activities, and P. aeruginosa cells expressing wild-type ExoS preferentially bound to the leading edge of T24 cells, where ExoS altered leading-edge architecture and actin anchoring in conjunction with interrupting T3S translocation. Inactivation of ExoS GAP activity allowed P. aeruginosa to be internalized and secrete ExoS within T24 cells, but as with wild-type ExoS, translocation was limited in association with disruption of actin anchoring. Inactivation of ExoS ADPRT activity resulted in significantly enhanced T3S translocation by P. aeruginosa cells that remained extracellular and in conjunction with maintenance of actin-plasma membrane association. Infection with P. aeruginosa expressing ExoS lacking both GAP and ADPRT activities resulted in the highest level of T3S translocation, and this occurred in conjunction with the entry and alignment of P. aeruginosa and ExoS along actin filaments. Collectively, in using ExoS mutants to modulate and visualize T3S translocation, we were able to (i) confirm effector secretion by internalized P. aeruginosa, (ii) differentiate the mechanisms underlying the effects of ExoS GAP and ADPRT activities on P. aeruginosa internalization and T3S translocation, (iii) confirm that ExoS ADPRT activity targeted a cellular substrate that interrupted T3S translocation, (iv) visualize the ability of P. aeruginosa and Exo

  16. Polysorbate 80 Inhibition of Pseudomonas aeruginosa Biofilm Formation and Its Cleavage by the Secreted Lipase LipA▿

    OpenAIRE

    Toutain-Kidd, Christine M.; Kadivar, Samoneh C.; Bramante, Carolyn T.; Bobin, Stephen A.; Zegans, Michael E.

    2008-01-01

    Surface-associated bacterial communities known as biofilms are an important source of nosocomial infections. Microorganisms such as Pseudomonas aeruginosa can colonize the abiotic surfaces of medical implants, leading to chronic infections that are difficult to eradicate. Our study demonstrates that polysorbate 80 (PS80), a surfactant commonly added to food and medicines, is able to inhibit biofilm formation by P. aeruginosa on a variety of surfaces, including contact lenses. Many clinical is...

  17. Fitness Cost of Fluoroquinolone Resistance in Clinical Isolates of Pseudomonas aeruginosa Differs by Type III Secretion Genotype

    Directory of Open Access Journals (Sweden)

    Melissa Agnello

    2016-10-01

    Full Text Available Fluoroquinolone (FQ resistance is highly prevalent among clinical strains of Pseudomonas aeruginosa, limiting treatment options. We have reported previously that highly virulent strains containing the exoU gene of the type III secretion system are more likely to be FQ-resistant than strains containing the exoS gene, as well as more likely to acquire resistance-conferring mutations in gyrA/B and parC/E. We hypothesize that FQ-resistance imposes a lower fitness cost on exoU compared to exoS strains, thus allowing for better adaptation to the FQ-rich clinical environment. We created isogenic mutants containing a common FQ-resistance conferring point mutation in parC from 3 exoU and 3 exoS clinical isolates and tested fitness in vitro using head-to-head competition assays. The mutation differentially affected fitness in the exoU and exoS strains tested. While the addition of the parC mutation dramatically increased fitness in one of the exoU strains leaving the other two unaffected, all three exoS strains displayed a general decrease in fitness. In addition, we found that exoU strains may be able to compensate for the fitness costs associated with the mutation through better regulation of supercoiling compared to the exoS strains. These results may provide a biological explanation for the observed predominance of the virulent exoU genotype in FQ-resistant clinical subpopulations and represent the first investigation into potential differences in fitness costs of FQ-resistance that are linked to the virulence genotype of P. aeruginosa. Understanding the fitness costs of antibiotic resistance and possibilities of compensation for these costs is essential for the rational development of strategies to combat the problem of antibiotic resistance.

  18. Pseudomonas aeruginosa biofilm infections

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim

    2014-01-01

    Bacteria in natural, industrial and clinical settings predominantly live in biofilms, i.e., sessile structured microbial communities encased in self-produced extracellular matrix material. One of the most important characteristics of microbial biofilms is that the resident bacteria display...... a remarkable increased tolerance toward antimicrobial attack. Biofilms formed by opportunistic pathogenic bacteria are involved in devastating persistent medical device-associated infections, and chronic infections in individuals who are immune-compromised or otherwise impaired in the host defense. Because...... the use of conventional antimicrobial compounds in many cases cannot eradicate biofilms, there is an urgent need to develop alternative measures to combat biofilm infections. The present review is focussed on the important opportunistic pathogen and biofilm model organism Pseudomonas aeruginosa. Initially...

  19. Pseudomonas aeruginosa Reduces VX-809 Stimulated F508del-CFTR Chloride Secretion by Airway Epithelial Cells.

    Directory of Open Access Journals (Sweden)

    Bruce A Stanton

    Full Text Available P. aeruginosa is an opportunistic pathogen that chronically infects the lungs of 85% of adult patients with Cystic Fibrosis (CF. Previously, we demonstrated that P. aeruginosa reduced wt-CFTR Cl secretion by airway epithelial cells. Recently, a new investigational drug VX-809 has been shown to increase F508del-CFTR Cl secretion in human bronchial epithelial (HBE cells, and, in combination with VX-770, to increase FEV1 (forced expiratory volume in 1 second by an average of 3-5% in CF patients homozygous for the F508del-CFTR mutation. We propose that P. aeruginosa infection of CF lungs reduces VX-809 + VX-770- stimulated F508del-CFTR Cl secretion, and thereby reduces the clinical efficacy of VX-809 + VX-770.F508del-CFBE cells and primary cultures of CF-HBE cells (F508del/F508del were exposed to VX-809 alone or a combination of VX-809 + VX-770 for 48 hours and the effect of P. aeruginosa on F508del-CFTR Cl secretion was measured in Ussing chambers. The effect of VX-809 on F508del-CFTR abundance was measured by cell surface biotinylation and western blot analysis. PAO1, PA14, PAK and 6 clinical isolates of P. aeruginosa (3 mucoid and 3 non-mucoid significantly reduced drug stimulated F508del-CFTR Cl secretion, and plasma membrane F508del-CFTR.The observation that P. aeruginosa reduces VX-809 and VX-809 + VX-770 stimulated F508del CFTR Cl secretion may explain, in part, why VX-809 + VX-770 has modest efficacy in clinical trials.

  20. Chronic Pseudomonas aeruginosa cervical osteomyelitis

    Directory of Open Access Journals (Sweden)

    Sujeet Kumar Meher

    2016-01-01

    Full Text Available Pseudomonas aeruginosa is a rare cause of osteomyelitis of the cervical spine and is usually seen in the background of intravenous drug use and immunocompromised state. Very few cases of osteomyelitis of the cervical spine caused by pseudomonas aeruginosa have been reported in otherwise healthy patients. This is a case presentation of a young female, who in the absence of known risk factors for cervical osteomyelitis presented with progressively worsening neurological signs and symptoms.

  1. Silver against Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Kirketerp-Møller, K.; Kristiansen, S.

    2007-01-01

    bacteria in both the planktonic and biofilm modes of growth. The action of silver on mature in vitro biofilms of Pseudomonas aeruginosa, a primary pathogen of chronic infected wounds, was investigated. The results show that silver is very effective against mature biofilms of P. aeruginosa...

  2. Polysorbate 80 inhibition of Pseudomonas aeruginosa biofilm formation and its cleavage by the secreted lipase LipA.

    Science.gov (United States)

    Toutain-Kidd, Christine M; Kadivar, Samoneh C; Bramante, Carolyn T; Bobin, Stephen A; Zegans, Michael E

    2009-01-01

    Surface-associated bacterial communities known as biofilms are an important source of nosocomial infections. Microorganisms such as Pseudomonas aeruginosa can colonize the abiotic surfaces of medical implants, leading to chronic infections that are difficult to eradicate. Our study demonstrates that polysorbate 80 (PS80), a surfactant commonly added to food and medicines, is able to inhibit biofilm formation by P. aeruginosa on a variety of surfaces, including contact lenses. Many clinical isolates of P. aeruginosa, as well as gram-negative and gram-positive clinical isolates, were also inhibited in their ability to form biofilms in the presence of PS80. A P. aeruginosa mutant able to form biofilms in the presence of this surfactant was identified and characterized, and it was revealed that this mutant overexpresses a lipase, LipA. Surfactants such as PS80 can be cleaved by lipases, and we demonstrate that PS80 is cleaved by LipA at its ester bond. Finally, polyethoxylated(20) oleyl alcohol, a chemical with a structure that is similar to that of PS80 but that lacks the ester bond of PS80, can inhibit the biofilm formation of P. aeruginosa strains, including the mutant overexpressing LipA. Our results demonstrate that surfactants such as PS80 can inhibit bacterial biofilm formation on medically relevant materials at concentrations demonstrated to be safe in humans and suggest that the understanding of the mechanisms of bacterial resistance to such surfactants will be important in developing clinically effective derivatives.

  3. Polysorbate 80 Inhibition of Pseudomonas aeruginosa Biofilm Formation and Its Cleavage by the Secreted Lipase LipA▿

    Science.gov (United States)

    Toutain-Kidd, Christine M.; Kadivar, Samoneh C.; Bramante, Carolyn T.; Bobin, Stephen A.; Zegans, Michael E.

    2009-01-01

    Surface-associated bacterial communities known as biofilms are an important source of nosocomial infections. Microorganisms such as Pseudomonas aeruginosa can colonize the abiotic surfaces of medical implants, leading to chronic infections that are difficult to eradicate. Our study demonstrates that polysorbate 80 (PS80), a surfactant commonly added to food and medicines, is able to inhibit biofilm formation by P. aeruginosa on a variety of surfaces, including contact lenses. Many clinical isolates of P. aeruginosa, as well as gram-negative and gram-positive clinical isolates, were also inhibited in their ability to form biofilms in the presence of PS80. A P. aeruginosa mutant able to form biofilms in the presence of this surfactant was identified and characterized, and it was revealed that this mutant overexpresses a lipase, LipA. Surfactants such as PS80 can be cleaved by lipases, and we demonstrate that PS80 is cleaved by LipA at its ester bond. Finally, polyethoxylated(20) oleyl alcohol, a chemical with a structure that is similar to that of PS80 but that lacks the ester bond of PS80, can inhibit the biofilm formation of P. aeruginosa strains, including the mutant overexpressing LipA. Our results demonstrate that surfactants such as PS80 can inhibit bacterial biofilm formation on medically relevant materials at concentrations demonstrated to be safe in humans and suggest that the understanding of the mechanisms of bacterial resistance to such surfactants will be important in developing clinically effective derivatives. PMID:18955535

  4. Airway epithelial cell tolerance to Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Verghese Margrith W

    2005-04-01

    Full Text Available Abstract Background The respiratory tract epithelium is a critical environmental interface that regulates inflammation. In chronic infectious airway diseases, pathogens may permanently colonize normally sterile luminal environments. Host-pathogen interactions determine the intensity of inflammation and thus, rates of tissue injury. Although many cells become refractory to stimulation by pathogen products, it is unknown whether the airway epithelium becomes either tolerant or hypersensitive in the setting of chronic infection. Our goals were to characterize the response of well-differentiated primary human tracheobronchial epithelial cells to Pseudomonas aeruginosa, to understand whether repeated exposure induced tolerance and, if so, to explore the mechanism(s. Methods The apical surface of well-differentiated primary human tracheobronchial epithelial cell cultures was repetitively challenged with Pseudomonas aeruginosa culture filtrates or the bacterial media control. Toxicity, cytokine production, signal transduction events and specific effects of dominant negative forms of signaling molecules were examined. Additional experiments included using IL-1β and TNFα as challenge agents, and performing comparative studies with a novel airway epithelial cell line. Results An initial challenge of the apical surface of polarized human airway epithelial cells with Pseudomonas aeruginosa culture filtrates induced phosphorylation of IRAK1, JNK, p38, and ERK, caused degradation of IκBα, generation of NF-κB and AP-1 transcription factor activity, and resulted in IL-8 secretion, consistent with activation of the Toll-like receptor signal transduction pathway. These responses were strongly attenuated following a second Pseudomonas aeruginosa, or IL-1β, but not TNFα, challenge. Tolerance was associated with decreased IRAK1 protein content and kinase activity and dominant negative IRAK1 inhibited Pseudomonas aeruginosa -stimulated NF-κB transcriptional

  5. Quantitative proteomics unravels that the post-transcriptional regulator Crc modulates the generation of vesicles and secreted virulence determinants of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Jose Antonio Reales-Calderón

    2015-09-01

    Full Text Available Crc is a post-transcriptional regulator in Pseudomonas aeruginosa that modulates its metabolism, but also its susceptibility to antibiotics and virulence. Most of P. aeruginosa virulence factors are secreted or engulfed in vesicles. A Crc deficient mutant was created and the extracellular vesicles associated exoproteome and the vesicle-free secretome was quantified using iTRAQ. Fifty vesicles-associated proteins were more abundant and 14 less abundant in the Crc-defective strain, whereas 37 were more abundant and 17 less abundant in the vesicle-free secretome. Different virulence determinants, such as ToxA, protease IV, azurin, chitin-binding protein, PlcB and Hcp1, were less abundant in the Crc-defective mutant. We also observed that the crc mutant presented an impaired vesicle-associated secretion of quorum sensing signal molecules and less cytotoxicity than its wild-type strain, in agreement with the low secretion of proteins related to virulence. Our results offer new insights into the mechanisms by which Crc regulates P. aeruginosa virulence, through the modulation of vesicle formation and secretion of both virulence determinants and quorum sensing signals.

  6. Sodium houttuyfonate, a potential phytoanticipin derivative of antibacterial agent, inhibits bacterial attachment and pyocyanine secretion of Pseudomonas aeruginosa by attenuating flagella-mediated swimming motility.

    Science.gov (United States)

    Shao, Jing; Cheng, Huijuan; Wang, Changzhong; Wu, Daqiang; Zhu, Xiaoli; Zhu, Lingling; Sun, Zhenxin

    2013-12-01

    Pseudomonas aeruginosa is a well-known clinical pathogen for its recalcitrant infection caused by biofilm formation which are initiated by flagella-mediated attachment. Sodium houttuyfonate (SH) is a natural phytoanticipin derivative of houttuynin and has anti-pathogenic effect on P. aeruginosa biofilm formation. In this paper, when using 1/2 × MIC SH, the diameter of P. aeruginosa swimming motility was sharply shortened to 36 % in 24 h incubation, and the fold changes of fliC required for swimming motility was 0.36 in 24 h cultivation, the adherence inhibition accounted for about 46 %, and the pyocyanin production decreased to 47 % after 1-day treatment and 56 % after 3-day treatment with obvious visual changes from dark green to light green, compared with the negative control. With the help of mass spectra and scanning electronic microscope, 1/2 × MIC SH was further testified to be enough to eradicate flagella and inhibit pyocyanin secretion of P. aeruginosa. The results do not only re-affirm the close interplay of attachment and virulence (i.e. swimming motility and pyocyanin), but also unravel the potential mechanism of SH on anti-biofilm of P. aeruginosa.

  7. Pseudomonas Aeruginosa Toxins

    Science.gov (United States)

    1982-09-01

    Ill.,111. PROTEASES One characteristic of P. aeruginosa is its ability to liquefy gelatin or digest casein. This property has been known to...Recently the ,- isolation of enterotoxic P. aeruginosa strains which give positive ileal loop tests in piglets and rabbits have been reported by

  8. Pseudomonas aeruginosa septicemia

    OpenAIRE

    Bocanegra C., Manuel; Departamento de Pediatría, Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Perú; Kiyan T., Manuel; Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Perú; Hinostroza Ñ., Fidel; Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Perú; Velarde Z., Nicolás; Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Perú; Bazán A., Augusto; Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Perú

    2014-01-01

    Experiments in burned mice were conditioned so that, with adequate numbers of living germs Pseudonoma aeruginosa or their toxins, as high as 80 mortalities occur to 100%, after 72 hours of the burn produced and inoculum. These animals and were treated with standard gamma globulin horse (6%), immunized against Pseudonoma aeruginosa, "antiserum" and dilute the hundredth human gamma globulin to 16%, dilute the hundredth equally. The degree of protectiveness conferred by these two types of gamma...

  9. Pseudomonas aeruginosa Virulence Analyzed in a Dictyostelium discoideum Host System

    OpenAIRE

    Cosson, Pierre; Zulianello, Laurence; Join-Lambert, Olivier; Faurisson, François; Gebbie, Leigh; Benghezal, Mohammed; Van Delden, Christian; Kocjancic Curty, Lasta; Köhler, Thilo

    2002-01-01

    Pseudomonas aeruginosa is an important opportunistic pathogen that produces a variety of cell-associated and secreted virulence factors. P. aeruginosa infections are difficult to treat effectively because of the rapid emergence of antibiotic-resistant strains. In this study, we analyzed whether the amoeba Dictyostelium discoideum can be used as a simple model system to analyze the virulence of P. aeruginosa strains. The virulent wild-type strain PAO1 was shown to inhibit growth of D. discoide...

  10. Recent advances in understanding Pseudomonas aeruginosa as a pathogen

    Science.gov (United States)

    Klockgether, Jens; Tümmler, Burkhard

    2017-01-01

    The versatile and ubiquitous Pseudomonas aeruginosa is an opportunistic pathogen causing acute and chronic infections in predisposed human subjects. Here we review recent progress in understanding P. aeruginosa population biology and virulence, its cyclic di-GMP-mediated switches of lifestyle, and its interaction with the mammalian host as well as the role of the type III and type VI secretion systems in P. aeruginosa infection. PMID:28794863

  11. Characterization of the Direct Interaction between Hybrid Sensor Kinases PA1611 and RetS That Controls Biofilm Formation and the Type III Secretion System in Pseudomonas aeruginosa.

    Science.gov (United States)

    Bhagirath, Anjali Y; Pydi, Sai P; Li, Yanqi; Lin, Chen; Kong, Weina; Chelikani, Prashen; Duan, Kangmin

    2017-02-10

    One of the leading causes of morbidity and mortality in cystic fibrosis (CF) patients is pulmonary infection with Pseudomonas aeruginosa, and the pathophysiology of pulmonary infection in CF is affected by the lifestyle of this micro-organism. RetS-GacS/A-RsmA is a key regulatory pathway in P. aeruginosa that determines the bacterium's lifestyle choice. Previously, we identified PA1611, a hybrid sensor kinase, as a new player in this pathway that interacts with RetS and influences biofilm formation and type III secretion system. In this study, we explored the structural and mechanistic basis of the interaction between PA1611 and RetS. We identified the amino acid residues critical for PA1611-RetS interactions by molecular modeling. These residues were then targeted for site-directed mutagenesis. Amino acid substitutions were carried out at seven key positions in PA1611 and at six corresponding key positions in RetS. The influence of such substitutions in PA1611 on the interaction was analyzed by bacterial two-hybrid assays. We carried out functional analysis of these mutants in P. aeruginosa for their effect on specific phenotypes. Two residues, F269 and E276, located within the histidine kinase A and histidine kinase-like ATPase domains of PA1611 were found to play crucial roles in the PA1611-RetS interaction and had profound effects on phenotypes. Corresponding mutations in RetS demonstrated similar results. We further confirmed that these mutations in PA1611 function through the GacS/GacA-RsmY/Z signaling pathway. Collectively, our findings provide a noncognate sensor kinase direct interaction model for a signaling pathway, key for lifestyle selection in P. aeruginosa, and targeting such interaction may serve as a novel way of controlling infections with P. aeruginosa.

  12. The role of type III secretion system and lens material on adhesion of Pseudomonas aeruginosa to contact lenses.

    Science.gov (United States)

    Shen, Elizabeth P; Tsay, Ruey-Yug; Chia, Jean-San; Wu, Semon; Lee, Jing-Wen; Hu, Fung-Rong

    2012-09-21

    To determine the distribution of invasive and cytotoxic genotypes among ocular isolates of P. aeruginosa and investigate the influence of the type III secretion system (T3SS) on adhesion to conventional, cosmetic, and silicone hydrogel contact lenses (CL). Clinical isolates from 2001 to 2010 were analyzed by multiplex PCR for exoS, exoU, and exoT genes. Bacterial adhesion to etafilcon, nelfilcon (gray colored), balafilcon, and galyfilcon CL with or without artificial tear fluid (ATF) incubation were compared. Surface characteristics were determined with scanning electron microscopy (SEM). Among 87 total isolates, 64 strains were from microbial keratitis cases. CL-related microbial keratitis (CLMK) isolates were mostly of the cytotoxic genotype (expressing exoU) (P = 0.002). No significant differences were found in bacterial adhesion to all types of CL between the genotypes under T3SS-inducing conditions. A trend for least bacterial adhesion of galyfilcon compared to the other CL was noted for both genotypes. Needle complex pscC mutants adhered less to all materials than the wild type (P contact lens adhesion. ATF-incubated CL had significantly more bacterial adhesion (P contact lens adhesion through complex interactions. Contact lens materials may also play an important role in the adherence of both genotypes of P. aeruginosa.

  13. First Record of Larval Secretions of Cochliomyia macellaria (Fabricius, 1775) (Diptera: Calliphoridae) Inhibiting the Growth of Staphylococcus aureus and Pseudomonas aeruginosa.

    Science.gov (United States)

    Masiero, F S; Aquino, M F K; Nassu, M P; Pereira, D I B; Leite, D S; Thyssen, P J

    2017-02-01

    Maggot debridement therapy (MDT) consists on the intentional and controlled application of sterilized larvae of the order Diptera on necrotic skin lesions with the purpose of cleaning necrotic tissue and removing pathogenic bacteria. During MDT, a marked antimicrobial activity has been reported in literature specially associated with antibacterial substances from Lucilia sericata (Meigen); however, regarding Cochliomyia macellaria (Fabricius), little is known. This study aimed to evaluate in vitro inhibition of bacterial growth of Pseudomonas aeruginosa and Staphylococcus aureus in contact with excretions and secretions (ES) from C. macellaria larvae. Larval ES were extracted in sterile distilled water and divided in three groups: ES, containing 400 μL of autoclaved ES; ES+BAC, containing 400 μL of autoclaved ES+0.5-μL bacterial inoculum; and CONT-BAC, containing 400 μL of sterile distilled water +0.5 μL of bacterial inoculum. Aliquots of each experimental group were plated by spreading onto Petri dishes. Seedings were made at 0, 1, 2, 4, and 12 h after the extraction of ES. In ES+BAC groups, inhibition of S. aureus was verified between times 1 and 2 h and P. aeruginosa was inhibited between 0 and 4 h. There was no growth observed in any ES group. In the CONT-BAC groups, the number of colonies from time 4 h became countless for S. aureus and decreased for P. aeruginosa. As reported in the literature, we note here that ES have excellent bactericidal activity for both gram-positive and gram-negative bacteria, and this study shows for the first time the action of the bactericidal activity of exosecretions of C. macellaria against S. aureus and P. aeruginosa.

  14. Clinical outcomes of multidrug resistant pseudomonas aeruginosa infection and the relationship with type III secretion system in patients with diabetic foot.

    Science.gov (United States)

    Zhang, Jinghang; Chu, Yuejie; Wang, Penghua; Ji, Xiaoyan; Li, Xiwen; Wang, Chao; Peng, Yue

    2014-09-01

    The objective was to analyze the clinical outcomes of multidrug resistant Pseudomonas aeruginosa (MDRPA) infection and determine the relationship between type III secretion system (TTSS) and MDRPA in diabetic foot (DF) patients. A total of 117 patients infected with P aeruginosa were recruited and grouped into MDRPA and non-MDRPA group according to antimicrobial susceptibility testing. TTSS genes were detected by polymerase chain reaction (PCR). Potential risk factors for MDRPA infection were examined using univariate and multivariate analyses. Clinical outcomes were compared on the basis of MDRPA or TTSS virulence gene. Previous antibiotic therapy, previous hospitalization and osteomyelitis were associated with MDRPA infection. MDRPA group had a higher amputation/toe rate (32.6% vs 16.2%) and lower healing rate (20.9% vs 41.9%) than non-MDRPA group (P = .032). A significantly higher proportion of exoU was present in MDRPA group (75.0% vs 25.0%, P infected with exoU isolates had a lower healing rate and higher amputation/toe rate (25.0% vs 65.2%, 33.3% vs 8.7%, P infected with exoS isolates. The exoU gene was predominance among MDRPA strains. The poor clinical outcomes of MDRPA infection in patients with DF were attributable to exoU gene. © The Author(s) 2014.

  15. The RNA Helicase DeaD Stimulates ExsA Translation To Promote Expression of the Pseudomonas aeruginosa Type III Secretion System

    Science.gov (United States)

    Intile, Peter J.; Balzer, Grant J.; Wolfgang, Matthew C.

    2015-01-01

    ABSTRACT The Pseudomonas aeruginosa type III secretion system (T3SS) is a primary virulence factor important for phagocytic avoidance, disruption of host cell signaling, and host cell cytotoxicity. ExsA is the master regulator of T3SS transcription. The expression, synthesis, and activity of ExsA is tightly regulated by both intrinsic and extrinsic factors. Intrinsic regulation consists of the well-characterized ExsECDA partner-switching cascade, while extrinsic factors include global regulators that alter exsA transcription and/or translation. To identify novel extrinsic regulators of ExsA, we conducted a transposon mutagenesis screen in the absence of intrinsic control. Transposon disruptions within gene PA2840, which encodes a homolog of the Escherichia coli RNA-helicase DeaD, significantly reduced T3SS gene expression. Recent studies indicate that E. coli DeaD can promote translation by relieving inhibitory secondary structures within target mRNAs. We report here that PA2840, renamed DeaD, stimulates ExsA synthesis at the posttranscriptional level. Genetic experiments demonstrate that the activity of an exsA translational fusion is reduced in a deaD mutant. In addition, exsA expression in trans fails to restore T3SS gene expression in a deaD mutant. We hypothesized that DeaD relaxes mRNA secondary structure to promote exsA translation and found that altering the mRNA sequence of exsA or the native exsA Shine-Dalgarno sequence relieved the requirement for DeaD in vivo. Finally, we show that purified DeaD promotes ExsA synthesis using in vitro translation assays. Together, these data reveal a novel regulatory mechanism for P. aeruginosa DeaD and add to the complexity of global regulation of T3SS. IMPORTANCE Although members of the DEAD box family of RNA helicases are appreciated for their roles in mRNA degradation and ribosome biogenesis, an additional role in gene regulation is now emerging in bacteria. By relaxing secondary structures in mRNAs, DEAD box

  16. The cytotoxin of Pseudomonas aeruginosa : Cytotoxicity requires proteolytic activation

    NARCIS (Netherlands)

    Orlik-Eisel, Gabriele; Lutz, Frieder; Henschen, Agnes; Eisel, Ulrich; Struckmeier, Martin; Kräuter, Josef; Niemann, Heiner

    The primary structure of a cytotoxin from Pseudomonas aeruginosa was determined by sequencing of the structural gene. The cytotoxin (31,700 Mr) lacks an N-terminal signal sequence for bacterial secretion but contains a pentapeptide consensus sequence commonly found in prokaryotic proteins which

  17. Dynamics of Pseudomonas aeruginosa Genome Evolution

    National Research Council Canada - National Science Library

    Kalai Mathee; Giri Narasimhan; Camilo Valdes; Xiaoyun Qiu; Jody M. Matewish; Michael Koehrsen; Antonis Rokas; Chandri N. Yandava; Reinhard Engels; Erliang Zeng; Raquel Olavarietta; Melissa Doud; Roger S. Smith; Philip Montgomery; Jared R. White; Paul A. Godfrey; Chinnappa Kodira; Bruce Birren; James E. Galagan; Stephen Lory

    2008-01-01

    One of the hallmarks of the Gram-negative bacterium Pseudomonas aeruginosa is its ability to thrive in diverse environments that includes humans with a variety of debilitating diseases or immune deficiencies...

  18. Pseudomonas aeruginosa: resistance to the max

    National Research Council Canada - National Science Library

    Poole, Keith

    2011-01-01

    Pseudomonas aeruginosa is intrinsically resistant to a variety of antimicrobials and can develop resistance during anti-pseudomonal chemotherapy both of which compromise treatment of infections caused by this organism...

  19. Antibiotic Conditioned Growth Medium of Pseudomonas Aeruginosa

    Science.gov (United States)

    Benathen, Isaiah A.; Cazeau, Barbara; Joseph, Njeri

    2004-01-01

    A simple method to study the consequences of bacterial antibiosis after interspecific competition between microorganisms is presented. Common microorganisms are used as the test organisms and Pseudomonas aeruginosa are used as the source of the inhibitor agents.

  20. Pseudomonas aeruginosa (Family Pseudomonadaceae) is an ...

    African Journals Online (AJOL)

    Pseudomonas aeruginosa (Family Pseudomonadaceae) is an obligate aerobic, motile, gram negative bacillus.which is able to grow and survive in almost any environment and resistant to temperature extremes. It is involved in the etiology of several diseases i.

  1. Force microscopic and thermodynamic analysis of the adhesion between Pseudomonas aeruginosa and Candida albicans

    NARCIS (Netherlands)

    Ovchinnikova, Ekaterina S.; Krom, Bastiaan P.; van der Mei, Henny C.; Busscher, Henk J.

    2012-01-01

    Pseudomonas aeruginosa expresses a plethora of virulence factors and many species have developed warning systems to detect and evade P. aeruginosa. Candida albicans detects P. aeruginosa by sensing the secreted bacterial quorum sensing molecule 3OC(12)HSL and responds by reverting to the yeast

  2. Force microscopic and thermodynamic analysis of the adhesion between Pseudomonas aeruginosa and Candida albicans

    NARCIS (Netherlands)

    Ovchinnikova, E.S.; Krom, B.P.; van der Mei, H.C.; Busscher, H.J.

    2012-01-01

    Pseudomonas aeruginosa expresses a plethora of virulence factors and many species have developed warning systems to detect and evade P. aeruginosa. Candida albicans detects P. aeruginosa by sensing the secreted bacterial quorum sensing molecule 3OC12HSL and responds by reverting to the yeast

  3. Interspecies Interaction between Pseudomonas aeruginosa and Other Microorganisms

    Science.gov (United States)

    Tashiro, Yosuke; Yawata, Yutaka; Toyofuku, Masanori; Uchiyama, Hiroo; Nomura, Nobuhiko

    2013-01-01

    Microbes interact with each other in multicellular communities and this interaction enables certain microorganisms to survive in various environments. Pseudomonas aeruginosa is a highly adaptable bacterium that ubiquitously inhabits diverse environments including soil, marine habitats, plants and animals. Behind this adaptivity, P. aeruginosa has abilities not only to outcompete others but also to communicate with each other to develop a multispecies community. In this review, we focus on how P. aeruginosa interacts with other microorganisms. P. aeruginosa secretes antimicrobial chemicals to compete and signal molecules to cooperate with other organisms. In other cases, it directly conveys antimicrobial enzymes to other bacteria using the Type VI secretion system (T6SS) or membrane vesicles (MVs). Quorum sensing is a central regulatory system used to exert their ability including antimicrobial effects and cooperation with other microbes. At least three quorum sensing systems are found in P. aeruginosa, Las, Rhl and Pseudomonas quinolone signal (PQS) systems. These quorum-sensing systems control the synthesis of extracellular antimicrobial chemicals as well as interaction with other organisms via T6SS or MVs. In addition, we explain the potential of microbial interaction analysis using several micro devices, which would bring fresh sensitivity to the study of interspecies interaction between P. aeruginosa and other organisms. PMID:23363620

  4. Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

    DEFF Research Database (Denmark)

    Johansen, Helle Krogh; Gøtzsche, Peter C

    2013-01-01

    Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed.......Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed....

  5. Biosynthesis of pyocyanin pigment by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    M.Z. El-Fouly

    2015-01-01

    Full Text Available Sixty-three isolates belonging to the genus Pseudomonas were isolated from different environmental sources including; soil, water and clinical specimens. Twenty out of them were identified as Pseudomonas aeruginosa and individually screened for pyocyanin production. P. aeruginosa R1; isolated from rice-cultivated soil and P. aeruginosa U3 selected from clinical specimen (Urinary tract infection were the highest pyocyanin producers; pyocyanin production reached 9.3 and 5.9 μg/ml, respectively on synthetic glucose supplemented nutrient medium (GSNB. The identification of both selected strains (P. aeruginosa R1 and P. aeruginosa U3 was confirmed by 16S rRNA, the similarity with other strains available in database was 97% (with P. aeruginosa FPVC 14 and 94% (with P. aeruginosa 13.A, respectively. P. aeruginosa R1 and P. aeruginosa U3 are accessed at gene bank with accession numbers KM924432 and KM603511, in the same order. Pyocyanin was extracted by standard methods, purified by column chromatography and characterized by UV-Vis absorption, mass spectrometry and nuclear magnetic resonance. The antimicrobial activity of purified pyocyanin against multi-drug resistant microbes was investigated; the efficiency of pyocyanin was more obvious in Gram +ve bacteria than Gram−ve bacteria and yeast. To reduce the cost of pyocyanin production, a new conventional medium based on cotton seed meal supplemented with peptone was designed. The pyocyanin production of both selected strains P. aeruginosa R1 and P. aeruginosa U3 using the new medium is increased by 30.1% and 17.2%, respectively in comparison with synthetic GSNB medium, while the cost of production process is reduced by 56.7%.

  6. Effect of Negative Pressure on Proliferation, Virulence Factor Secretion, Biofilm Formation, and Virulence-Regulated Gene Expression of Pseudomonas aeruginosa In Vitro

    Directory of Open Access Journals (Sweden)

    Guo-Qi Wang

    2016-01-01

    Full Text Available Objective. To investigate the effect of negative pressure conditions induced by NPWT on P. aeruginosa. Methods. P. aeruginosa was cultured in a Luria–Bertani medium at negative pressure of −125 mmHg for 24 h in the experimental group and at atmospheric pressure in the control group. The diameters of the colonies of P. aeruginosa were measured after 24 h. ELISA kit, orcinol method, and elastin-Congo red assay were used to quantify the virulence factors. Biofilm formation was observed by staining with Alexa Fluor® 647 conjugate of concanavalin A (Con A. Virulence-regulated genes were determined by quantitative RT-PCR. Results. As compared with the control group, growth of P. aeruginosa was inhibited by negative pressure. The colony size under negative pressure was significantly smaller in the experimental group than that in the controls (p<0.01. Besides, reductions in the total amount of virulence factors were observed in the negative pressure group, including exotoxin A, rhamnolipid, and elastase. RT-PCR results revealed a significant inhibition in the expression level of virulence-regulated genes. Conclusion. Negative pressure could significantly inhibit the growth of P. aeruginosa. It led to a decrease in the virulence factor secretion, biofilm formation, and a reduction in the expression level of virulence-regulated genes.

  7. Stratified growth in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Werner, E.; Roe, F.; Bugnicourt, A.

    2004-01-01

    In this study, stratified patterns of protein synthesis and growth were demonstrated in Pseudomonas aeruginosa biofilms. Spatial patterns of protein synthetic activity inside biofilms were characterized by the use of two green fluorescent protein (GFP) reporter gene constructs. One construct...... of oxygen limitation in the biofilm. Oxygen microelectrode measurements showed that oxygen only penetrated approximately 50 mum into the biofilm. P. aeruginosa was incapable of anaerobic growth in the medium used for this investigation. These results show that while mature P. aeruginosa biofilms contain...

  8. Macrolides protect against Pseudomonas aeruginosa infection via inhibition of inflammasomes.

    Science.gov (United States)

    Fan, Li-Chao; Lin, Jie-Lu; Yang, Jia-Wei; Mao, Bei; Lu, Hai-Wen; Ge, Bao-Xue; Choi, Augustine M K; Xu, Jin-Fu

    2017-10-01

    Macrolides antibiotics have been effectively used in many chronic diseases, especially with Pseudomonas aeruginosa (P. aeruginosa) infection. The mechanisms underlying the therapeutic effects of macrolides in these diseases remain poorly understood. We established a mouse model of chronic lung infection using P. aeruginosa agar-beads, with azithromycin treatment or placebo. Lung injury, bacterial clearance, and inflammasome-related proteins were measured. In vitro, the inflammasomes activation induced by flagellin or ATP were assessed in LPS-primed macrophages with or without macrolides treatment. Plasma IL-18 levels were determined from patients who were diagnosed with bronchiectasis isolated with or without P. aeruginosa and treated with azithromycin for 3-5 days. Azithromycin treatment enhanced bacterial clearance and attenuated lung injury in mice chronically infected with P. aeruginosa, which resulted from the inhibition of caspase-1-dependent IL-1β and IL-18 secretion. In vitro, azithromycin and erythromycin inhibited NLRC4 and NLRP3 inflammasomes activation. Plasma IL-18 levels were higher in bronchiectasis patients with P. aeruginosa isolation compared with healthy controls. Azithromycin administration markedly decreased IL-18 secretion in bronchiectasis patients. The results of this study reveal that azithromycin and erythromycin exert a novel anti-inflammatory effect by attenuating inflammasomes activation, which suggests potential treatment options for inflammasome-related diseases. Copyright © 2017 the American Physiological Society.

  9. Antibiotics Susceptibility Pattern of Pseudomonas aeruginosa ...

    African Journals Online (AJOL)

    ABSTRACT: This work investigated the prevalence and antibiotics sensitivity of Pseudomonas aeruginosa isolated from wounds of patients attending Ahmadu Bello University Teaching Hospital (ABUTH), Zaria-Nigeria. One hundred Isolates were characterized and identified from the specimens using standard ...

  10. Characterization of drug resistant Pseudomonas aeruginosa and ...

    African Journals Online (AJOL)

    Despite the fact that they remain asymptomatic in many cases, they nevertheless play significant roles in the epidemiology of these pathogens through their dissemination to the public, sometimes through the food chain. Four multidrug resistant Gram negative pathogens including: 2 Pseudomonas aeruginosa and 2 Proteus ...

  11. Mast cells protect against Pseudomonas aeruginosa-induced lung injury.

    Science.gov (United States)

    Junkins, Robert D; Carrigan, Svetlana O; Wu, Zhengli; Stadnyk, Andrew W; Cowley, Elizabeth; Issekutz, Thomas; Berman, Jason; Lin, Tong-Jun

    2014-08-01

    Pseudomonas aeruginosa, an opportunistic pathogen, is the leading cause of morbidity and mortality in immune-compromised individuals. Maintaining the integrity of the respiratory epithelium is critical for an effective host response to P. aeruginosa. Given the close spatial relationship between mast cells and the respiratory epithelium, and the importance of tightly regulated epithelial permeability during lung infections, we examined whether mast cells influence airway epithelial integrity during P. aeruginosa lung infection in a mouse model. We found that mast cell-deficient Kit(W-sh)/Kit(W-sh) mice displayed greatly increased epithelial permeability, bacterial dissemination, and neutrophil accumulation compared with wild-type animals after P. aeruginosa infection; these defects were corrected on reconstitution with mast cells. An in vitro Transwell co-culture model further demonstrated that a secreted mast cell factor decreased epithelial cell apoptosis and tumor necrosis factor production after P. aeruginosa infection. Together, our data demonstrate a previously unrecognized role for mast cells in the maintenance of epithelial integrity during P. aeruginosa infection, through a mechanism that likely involves prevention of epithelial apoptosis and tumor necrosis factor production. Our understanding of mechanisms of the host response to P. aeruginosa will open new avenues for the development of successful preventative and treatment strategies. Copyright © 2014 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  12. Pseudomonas aeruginosa virulence analyzed in a Dictyostelium discoideum host system.

    Science.gov (United States)

    Cosson, Pierre; Zulianello, Laurence; Join-Lambert, Olivier; Faurisson, François; Gebbie, Leigh; Benghezal, Mohammed; Van Delden, Christian; Curty, Lasta Kocjancic; Köhler, Thilo

    2002-06-01

    Pseudomonas aeruginosa is an important opportunistic pathogen that produces a variety of cell-associated and secreted virulence factors. P. aeruginosa infections are difficult to treat effectively because of the rapid emergence of antibiotic-resistant strains. In this study, we analyzed whether the amoeba Dictyostelium discoideum can be used as a simple model system to analyze the virulence of P. aeruginosa strains. The virulent wild-type strain PAO1 was shown to inhibit growth of D. discoideum. Isogenic mutants deficient in the las quorum-sensing system were almost as inhibitory as the wild type, while rhl quorum-sensing mutants permitted growth of Dictyostelium cells. Therefore, in this model system, factors controlled by the rhl quorum-sensing system were found to play a central role. Among these, rhamnolipids secreted by the wild-type strain PAO1 could induce fast lysis of D. discoideum cells. By using this simple model system, we predicted that certain antibiotic-resistant mutants of P. aeruginosa should show reduced virulence. This result was confirmed in a rat model of acute pneumonia. Thus, D. discoideum could be used as a simple nonmammalian host system to assess pathogenicity of P. aeruginosa.

  13. Secretory IgA as a diagnostic tool for Pseudomonas aeruginosa respiratory colonization

    DEFF Research Database (Denmark)

    Aanaes, Kasper; Johansen, Helle Krogh; Poulsen, Steen Seier

    2012-01-01

    BACKGROUND: Pseudomonas aeruginosa sinusitis may be the focus for intermittent lung colonization in patients with cystic fibrosis (CF). The sinusitis may induce elevated IgA levels in nasal secretion and saliva against P. aeruginosa. METHODS: 120 CF patients chronically infected, intermittently c...... patients chronically infected, intermittently colonized, and without P. aeruginosa in the lungs. The diagnostic value of the IgA ELISA awaits a prospective study....

  14. The immune system vs. Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Jensen, Peter Østrup; Givskov, Michael; Bjarnsholt, Thomas

    2010-01-01

    Ilya Metchnikoff and Paul Ehrlich were awarded the Nobel price in 1908. Since then, numerous studies have unraveled a multitude of mechanistically different immune responses to intruding microorganisms. However, in the vast majority of these studies, the underlying infectious agents have appeared...... the present review on the immune system vs. biofilm bacteria is focused on Pseudomonas aeruginosa (mainly because this is the most thoroughly studied), many of the same mechanisms are also seen with biofilm infections generated by other microorganisms....

  15. Nosocomial outbreak of Pseudomonas aeruginosa endophthalmitis.

    Science.gov (United States)

    Mateos, I; Valencia, R; Torres, M J; Cantos, A; Conde, M; Aznar, J

    2006-11-01

    We describe an outbreak of nosocomial endophthalmitis due to a common source, which was determined to be trypan blue solution prepared in the hospital's pharmacy service. We assume that viable bacteria probably gained access to the trypan blue stock solution during cooling after autoclaving. The temporal cluster of Pseudomonas aeruginosa endophthalmitis was readily perceived on the basis of clinical and microbiological findings, and an exogenous source of contamination was unequivocally identified by means of DNA fingerprinting.

  16. Complement activation by Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Jensen, E T; Kharazmi, A; Garred, P

    1993-01-01

    In chronic infections, such as the bronchopulmonary Pseudomonas aeruginosa infection in cystic fibrosis (CF) patients, bacteria persist despite an intact host immune defense and frequent antibiotic treatment. An important reason for the persistence of the bacteria is their capacity for the biofilm...... mode of growth. In this study we investigated the role of biofilms in activation of complement, a major contributor to the inflammatory process. Complement activation by P. aeruginosa was examined in a complement consumption assay, production of C3 and factor B conversion products assessed by crossed...... immuno-electrophoresis, C5a generation tested by a PMN chemotactic assay, and terminal complement complex formation measured by ELISA. Two of the four assays showed that P. aeruginosa grown in biofilm activated complement less than planktonic bacteria, and all assays showed that activation by intact...

  17. Cooperative production of siderophores by Pseudomonas aeruginosa.

    Science.gov (United States)

    Harrison, Freya; Buckling, Angus

    2009-01-01

    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.

  18. Pseudomonas aeruginosa Dose-Response and Bathing Water Infection

    Science.gov (United States)

    Pseudomonas aeruginosa is the most commonly identified opportunistic pathogen associated with pool acquired bather disease. To better understand why this microorganism poses this protracted problem we recently appraised P. aeruginosa pool risk management. Much is known about the ...

  19. Alginate overproduction affects Pseudomonas aeruginosa biofilm structure and function

    DEFF Research Database (Denmark)

    Hentzer, Morten; Teitzel, G.M.; Balzer, G.J.

    2001-01-01

    During the course of chronic cystic fibrosis (CF) infections, Pseudomonas aeruginosa undergoes a conversion to a mucoid phenotype, which is characterized by overproduction of the exopolysaccharide alginate. Chronic P. aeruginosa infections involve surface-attached, highly antibiotic-resistant com...

  20. [Iron uptake and biofilm formation in Pseudomonas aeruginosa].

    Science.gov (United States)

    Yu, Shan; Ma, Luyan

    2017-09-25

    Biofilms are surface-associated communities of microorganisms embedded within self-secreted extracellular polymeric substances, and a major cause of chronic and persistent infections. Respiratory Pseudomona aeruginosa infection is the leading reason for morbidity and mortality in cystic fibrosis patients. The formation of biofilms by P. aeruginosa in the airway is thought to increase persistence and antibiotic resistance during infection. Biofilm formation of P. aeruginosa is regulated by complicated signaling systems including quorum sensing and two-component systems that control the synthesis of extracellular polymeric substances. Furthermore, iron is an essential and scarce nutrient for bacteria and an important signal factor. P. aeruginosa has developed multiple iron uptake systems to sequester enough iron for its survival, with important regulatory roles in both release of virulence factors and formation of biofilms. In this review, we summarize recent advances in biofilm formation and its regulation along with the iron-uptake strategies in P. aeruginosa, to provide new insights and understanding to fight bacterial biofilms.

  1. Activation of Pseudomonas aeruginosa elastase in Pseudomonas putida by triggering dissociation of the propeptide-enzyme complex

    NARCIS (Netherlands)

    Braun, P; Bitter, W; Tommassen, J

    2000-01-01

    The propeptide of Pseudomonas aeruginosa elastase functions both as an intramolecular chaperone required for the folding of the enzyme and as an inhibitor that prevents activity of the enzyme before its secretion into the extracellular medium. Since expression of the lasB gene, which encodes

  2. Redox-active pyocyanin secreted by Pseudomonas aeruginosa 7NSK2 triggers systemic resistance to Magnaporthe grisea but enhances Rhizoctonia solani susceptibility in rice.

    Science.gov (United States)

    De Vleesschauwer, David; Cornelis, Pierre; Höfte, Monica

    2006-12-01

    Pseudomonas aeruginosa 7NSK2 induces resistance in dicots through a synergistic interaction of the phenazine pyocyanin and the salicylic acid-derivative pyochelin. Root inoculation of the monocot model rice with 7NSK2 partially protected leaves against blast disease (Magnaporthe grisea) but failed to consistently reduce sheath blight (Rhizoctonia solani). Only mutations interfering with pyocyanin production led to a significant decrease in induced systemic resistance (ISR) to M. grisea, and in trans complementation for pyocyanin production restored the ability to elicit ISR. Intriguingly, pyocyanin-deficient mutants, unlike the wild type, triggered ISR against R. solani. Hence, bacterial pyocyanin plays a differential role in 7NSK2-mediated ISR in rice. Application of purified pyocyanin to hydroponically grown rice seedlings increased H202 levels locally on the root surface as well as a biphasic H202 generation pattern in distal leaves. Co-application of pyocyanin and the antioxidant sodium ascorbate alleviated the opposite effects of pyocyanin on rice blast and sheath blight development, suggesting that the differential effectiveness of pyocyanin with respect to 7NSK2-triggered ISR is mediated by transiently elevated H202 levels in planta. The cumulative results suggest that reactive oxygen species act as a double-edged sword in the interaction of rice with the hemibiotroph M. grisea and the necrotroph R. solani.

  3. Host and Pathogen Biomarkers for Severe Pseudomonas aeruginosa Infections.

    Science.gov (United States)

    Juan, Carlos; Peña, Carmen; Oliver, Antonio

    2017-02-15

    Pseudomonas aeruginosa is among the leading causes of severe nosocomial infections, particularly affecting critically ill and immunocompromised patients. Here we review the current knowledge on the factors underlying the outcome of P. aeruginosa nosocomial infections, including aspects related to the pathogen, the host, and treatment. Intestinal colonization and previous use of antibiotics are key risk factors for P. aeruginosa infections, whereas underlying disease, source of infection, and severity of acute presentation are key host factors modulating outcome; delayed adequate antimicrobial therapy is also independently associated with increased mortality. Among pathogen-related factors influencing the outcome of P. aeruginosa infections, antibiotic resistance, and particularly multidrug-resistant profiles, is certainly of paramount relevance, given its obvious effect on the chances of appropriate empirical therapy. However, the direct impact of antibiotic resistance in the severity and outcomes of P. aeruginosa infections is not yet well established. The interplay between antibiotic resistance, virulence, and the concerning international high-risk clones (such as ST111, ST175, and ST235) still needs to be further analyzed. On the other hand, differential presence or expression of virulence factors has been shown to significantly impact disease severity and mortality. The likely more deeply studied P. aeruginosa virulence determinant is the type III secretion system (T3SS); the production of T3SS cytotoxins, and particularly ExoU, has been well established to determine a worse outcome both in respiratory and bloodstream infections. Other relevant pathogen-related biomarkers of severe infections include the involvement of specific clones or O-antigen serotypes, the presence of certain horizontally acquired genomic islands, or the expression of other virulence traits, such as the elastase. Finally, recent data suggest that host genetic factors may also modulate the

  4. Cell death in Pseudomonas aeruginosa biofilm development

    DEFF Research Database (Denmark)

    Webb, J.S.; Thompson, L.S.; James, S.

    2003-01-01

    Bacteria growing in biofilms often develop multicellular, three-dimensional structures known as microcolonies. Complex differentiation within biofilms of Pseudomonas aeruginosa occurs, leading to the creation of voids inside microcolonies and to the dispersal of cells from within these voids....... However, key developmental processes regulating these events are poorly understood. A normal component of multicellular development is cell death. Here we report that a repeatable pattern of cell death and lysis occurs in biofilms of P. aeruginosa during the normal course of development. Cell death...... occurred with temporal and spatial organization within biofilms, inside microcolonies, when the biofilms were allowed to develop in continuous-culture flow cells. A subpopulation of viable cells was always observed in these regions. During the onset of biofilm killing and during biofilm development...

  5. Pseudomonas aeruginosa endophthalmitis masquerading as chronic uveitis

    Directory of Open Access Journals (Sweden)

    Kalpana Badami Nagaraj

    2013-01-01

    Full Text Available A 65-year-old male presented with decreased vision in the left eye of 15-day duration after having undergone an uneventful cataract surgery 10 months back. He had been previously treated with systemic steroids for recurrent uveitis postoperatively on three occasions in the same eye. B-scan ultrasonography showed multiple clumplike echoes suggestive of vitreous inflammation. Aqueous tap revealed Pseudomonas aeruginosa sensitive to ciprofloxacin. The patient was treated with intravitreal ciprofloxacin and vancomycin along with systemic ciprofloxacin with good clinical response. Even a virulent organism such as P.aeruginosa can present as a chronic uveitis, which, if missed, can lead to a delay in accurate diagnosis and appropriate management.

  6. Pseudomonas aeruginosa biofilms in cystic fibrosis

    DEFF Research Database (Denmark)

    Høiby, Niels; Ciofu, Oana; Bjarnsholt, Thomas

    2010-01-01

    of mutations, slow growth and adaptation of the bacteria to the conditions in the lungs, and to antibiotic therapy. Low bacterial metabolic activity and increase of doubling times of the bacterial cells in CF lungs are responsible for some of the tolerance to antibiotics. Conventional resistance mechanisms......, such as chromosomal ß-lactamase, upregulated efflux pumps, and mutations of antibiotic target molecules in the bacteria, also contribute to the survival of P. aeruginosa biofilms. Biofilms can be prevented by early aggressive antibiotic prophylaxis or therapy, and they can be treated by chronic suppressive therapy.......The persistence of chronic Pseudomonas aeruginosa lung infections in cystic fibrosis (CF) patients is due to biofilm-growing mucoid (alginate-producing) strains. A biofilm is a structured consortium of bacteria, embedded in a self-produced polymer matrix consisting of polysaccharide, protein...

  7. 33 original article infections a pseudomonas aeruginosa dans un ...

    African Journals Online (AJOL)

    boaz

    institution of effective resistance surveillance and infection control measures. . Keywords: Pseudomonas aeruginosa, National Hospital Abuja, Susceptibility. INFECTIONS A PSEUDOMONAS AERUGINOSA DANS UN HOPITAL TERTIAIRE. AU NIGERIA. *Iregbu KC, Eze SO,. Département de Microbiologie Médicale and ...

  8. Difference of Type 3 secretion system (T3SS) effector gene genotypes (exoU and exoS) and its implication to antibiotics resistances in isolates of Pseudomonas aeruginosa from chronic otitis media.

    Science.gov (United States)

    Park, Min-Hyun; Kim, So Young; Roh, Eun Yun; Lee, Ho Sun

    2017-06-01

    Type 3 secretion system (T3SS) is the most important virulence factor in Pseudomonas aeruginosa infection. Of the various T3SS effector genes, exoS and exoU showed mutually exclusive distributions, and these two genes showed varied virulence. In many pseudomonal infections, the distribution of these genes showed different pattern and it influenced severity of infection. This study was aimed to evaluate differences of virulence factors and antibiotics resistance between chronic otitis media and other body infection caused by P. aeruginosa. To estimate the prevalence of effector genes of T3SS, especially the distributions of exoS and exoU genes and their association with antibiotic resistance in COM, we compared the prevalence of T3SS genes in isolates from COM with those from lower respiratory infection and bacteremia. Other virulence genes, including groEL, pilA, ndvB, lasB, rhlI, and apr, were also studied to evaluate prevalence. These isolates were tested for antibiotic susceptibility, and we examined the association between antibiotic susceptibility and the prevalence of T3SS effector genes. The COM group showed a significantly higher exoU-positive rate than the control group (70.6% vs. 6.7%; Paeruginosa and ciprofloxacin resistance can explain the chronicity and intractability of infection in COM. Elucidation of this pathogenicity will facilitate the development of new treatment options for COM patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Pyoverdine, the Major Siderophore in Pseudomonas aeruginosa, Evades NGAL Recognition

    Directory of Open Access Journals (Sweden)

    Mary E. Peek

    2012-01-01

    Full Text Available Pseudomonas aeruginosa is the most common pathogen that persists in the cystic fibrosis lungs. Bacteria such as P. aeruginosa secrete siderophores (iron-chelating molecules and the host limits bacterial growth by producing neutrophil-gelatinase-associated lipocalin (NGAL that specifically scavenges bacterial siderophores, therefore preventing bacteria from establishing infection. P. aeruginosa produces a major siderophore known as pyoverdine, found to be important for bacterial virulence and biofilm development. We report that pyoverdine did not bind to NGAL, as measured by tryptophan fluorescence quenching, while enterobactin bound to NGAL effectively causing a strong response. The experimental data indicate that pyoverdine evades NGAL recognition. We then employed a molecular modeling approach to simulate the binding of pyoverdine to human NGAL using NGAL’s published crystal structures. The docking of pyoverdine to NGAL predicted nine different docking positions; however, neither apo- nor ferric forms of pyoverdine docked into the ligand-binding site in the calyx of NGAL where siderophores are known to bind. The molecular modeling results offer structural support that pyoverdine does not bind to NGAL, confirming the results obtained in the tryptophan quenching assay. The data suggest that pyoverdine is a stealth siderophore that evades NGAL recognition allowing P. aeruginosa to establish chronic infections in CF lungs.

  10. Biotransformation of myrcene by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Hashemi Elham

    2011-05-01

    Full Text Available Abstract Background Dihydrolinalool and terpineol are sources of fragrances that provide a unique volatile terpenoid alcohol of low toxicity and thus are widely used in the perfumery industry, in folk medicine, and in aromatherapy. They are important chemical constituents of the essential oil of many plants. Previous studies have concerned the biotransformation of limonene by Pseudomonas putida. The objective of this research was to study biotransformation of myrcene by Pseudomonas aeruginosa. The culture preparation was done using such variables as different microbial methods and incubation periods to obtain maximum cells of P. aeruginosa for myrcene biotransformation. Results It was found that myrcene was converted to dihydrolinalool and 2,6-dimethyloctane in high percentages. The biotransformation products were identified by Fourier-transform infrared spectroscopy (FT-IR, ultraviolet (UV analysis, gas chromatography (GC, and gas chromatography-mass spectroscopy (GC-MS. Comparison of the different incubation times showed that 3 days was more effective, the major products being 2,6-dimethyloctane (90.0% and α-terpineol (7.7% and comprising 97.7%. In contrast, the main compounds derived for an incubation time of 1.5 days were dihydrolinalool (79.5% and 2,6-dimethyloctane (9.3%, with a total yield of 88.8%.

  11. Antivirulence activity of azithromycin in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Francesco eImperi

    2014-04-01

    Full Text Available Antibiotics represent our bulwark to combat bacterial infections, but the spread of antibiotic resistance compromises their clinical efficacy. Alternatives to conventional antibiotics are urgently needed in order to complement the existing antibacterial arsenal. The macrolide antibiotic azithromycin (AZM provides a paradigmatic example of an unconventional antibacterial drug. Besides its growth-inhibiting activity, AZM displays potent anti-inflammatory properties, as well as antivirulence activity on some intrinsically resistant bacteria, such as Pseudomonas aeruginosa. In this bacterium, the antivirulence activity of AZM mainly relies on its ability to interact with the ribosome, resulting in direct and/or indirect repression of specific subsets of genes involved in virulence, quorum sensing, biofilm formation and intrinsic antibiotic resistance. Both clinical experience and clinical trials have shown the efficacy of AZM in the treatment of chronic pulmonary infections caused by P. aeruginosa. The aim of this review is to combine results from laboratory studies with evidence from clinical trials in order to unify the information on the in vivo mode of action of AZM in P. aeruginosa infection.

  12. Risk assessment of Pseudomonas aeruginosa in water.

    Science.gov (United States)

    Mena, Kristina D; Gerba, Charles P

    2009-01-01

    drinking water industry, very little has been reported regarding the role of P. aeruginosa in biofilms. Tap water appears to be a significant route of transmission in hospitals, from colonization of plumbing fixtures. It is still not clear if the colonization results from the water in the distribution system, or personnel use within the hospital. Infections and colonization can be significantly reduced by placement of filters on the water taps. The oral dose of P. aeruginosa required to establish colonization in a healthy subject is high (George et al. 1989a). During dose-response studies, even when subjects (mice or humans) were colonized via ingestion, there was no evidence of disease. P. aeruginosa administered by the aerosol route at levels of 10(7) cells did cause disease symptoms in mice, and was lethal in aerosolized doses of 10(9) cells. Aerosol dose-response studies have not been undertaken with human subjects. Human health risks associated with exposure to P. aeruginosa via drinking water ingestion were estimated using a four-step risk assessment approach. The risk of colonization from ingesting P. aeruginosa in drinking water is low. The risk is slightly higher if the subject is taking an antibiotic resisted by P. aeruginosa. The fact that individuals on ampicillin are more susceptible to Pseudomonas gastrointestinal infection probably results from suppression of normal intestinal flora, which would allow Pseudomonas to colonize. The process of estimating risk was significantly constrained because of the absence of specific (quantitative) occurrence data for Pseudomonas. Sensitivity analysis shows that the greatest source of variability/uncertainty in the risk assessment is from the density distribution in the exposure rather than the dose-response or water consumption distributions. In summary, two routes appear to carry the greatest health risks from contacting water contaminated with P. aeruginosa (1) skin exposure in hot tubs and (2) lung exposure from

  13. Therapy of Pseudomonas aeruginosa infections with tobramycin.

    Science.gov (United States)

    Blair, D C; Fekety, F R; Bruce, B; Silva, J; Archer, G

    1975-07-01

    The efficacy of tobramycin in doses of 2.7 to 5.6 mg/kg per day in 29 courses of therapy in 25 hospitalized patients with serious Pseudomonas aeruginosa infections was studied. Eighty-three percent of the P. aeruginosa strains showed zones of inhibition of 16 mm or more around a 10-mug tobramycin disk in the Bauer-Kirby disk method. Tobramycin minimal inhibitory concentration ranged from <0.05 to 1.5 mug/ml (microtiter twofold dilution method); for gentamicin they ranged from 0.05 to 6.2 mug/ml; corresponding geometric means were 0.19 and 0.49 mug/ml. Therapy was given for a median of 10 days (mean 19, range 1 to 83). The clinically satisfactory response rate for the 29 courses of therapy was 52%: critically ill, 44%; seriously ill, 50%; moderately ill, 80%. The response rates for various sites of infection were bone and cartilage, 100%; urinary tract infection, 56%; wound, 50%; respiratory tract, 67%; septicemia, 40%; abscess, 0%; burns, 44%. No adverse reactions were seen. Serum concentration (mug/ml +/- standard deviation) of tobramycin determined by an agar-well plate method, were 4.81 +/- 2.17 (1 h); 3.24 +/- 1.43 (2 h); 2.35 +/- 1.30 (4 h); and 1.40 +/- 1.09 (8 h). Tobramycin appears to be as effacacious as gentamicin in the treatment of serious P. aeruginosa infections and has a theoretical advantage of lower minimal inhibitory concentration for P. aeruginosa. The data suggest that, for life-threatening infections, dosages of tobramycin may need to be increased over those used in this study.

  14. Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

    DEFF Research Database (Denmark)

    Johansen, H.K.; Gøtzsche, Peter C.; Johansen, Helle Krogh

    2008-01-01

    BACKGROUND: Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed. OBJECTIVES......: To assess the effectiveness of vaccination against Pseudomonas aeruginosa in cystic fibrosis. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register using the terms vaccines AND pseudomonas (last search May 2008) and PubMed using the terms vaccin* AND cystic...... fibrosis (last search May 2008). SELECTION CRITERIA: Randomised trials (published or unpublished) comparing Pseudomonas aeruginosa vaccines (oral, parenteral or intranasal) with control vaccines or no intervention in cystic fibrosis. DATA COLLECTION AND ANALYSIS: The authors independently selected trials...

  15. Targeting quorum sensing in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Jakobsen, Tim Holm; Bjarnsholt, Thomas; Jensen, Peter Østrup

    2013-01-01

    Bacterial resistance to conventional antibiotics combined with an increasing acknowledgement of the role of biofilms in chronic infections has led to a growing interest in new antimicrobial strategies that target the biofilm mode of growth. In the aggregated biofilm mode, cell-to-cell communication...... systems involved in the process known as quorum sensing regulate coordinated expression of virulence with immune shielding mechanisms and antibiotic resistance. For two decades, the potential of interference with quorum sensing by small chemical compounds has been investigated with the aim of developing...... alternative antibacterial strategies. Here, we review state of the art research of quorum sensing inhibitors against the opportunistic human pathogen Pseudomonas aeruginosa, which is found in a number of biofilm-associated infections and identified as the predominant organism infecting the lungs of cystic...

  16. Atomic Structure of Type VI Contractile Sheath from Pseudomonas aeruginosa.

    Science.gov (United States)

    Salih, Osman; He, Shaoda; Planamente, Sara; Stach, Lasse; MacDonald, James T; Manoli, Eleni; Scheres, Sjors H W; Filloux, Alain; Freemont, Paul S

    2017-12-21

    Pseudomonas aeruginosa has three type VI secretion systems (T6SSs), H1-, H2-, and H3-T6SS, each belonging to a distinct group. The two T6SS components, TssB/VipA and TssC/VipB, assemble to form tubules that conserve structural/functional homology with tail sheaths of contractile bacteriophages and pyocins. Here, we used cryoelectron microscopy to solve the structure of the H1-T6SS P. aeruginosa TssB1C1 sheath at 3.3 Å resolution. Our structure allowed us to resolve some features of the T6SS sheath that were not resolved in the Vibrio cholerae VipAB and Francisella tularensis IglAB structures. Comparison with sheath structures from other contractile machines, including T4 phage and R-type pyocins, provides a better understanding of how these systems have conserved similar functions/mechanisms despite evolution. We used the P. aeruginosa R2 pyocin as a structural template to build an atomic model of the TssB1C1 sheath in its extended conformation, allowing us to propose a coiled-spring-like mechanism for T6SS sheath contraction. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  17. Quorum-sensing inhibition abrogates the deleterious impact of Pseudomonas aeruginosa on airway epithelial repair.

    Science.gov (United States)

    Ruffin, Manon; Bilodeau, Claudia; Maillé, Émilie; LaFayette, Shantelle L; McKay, Geoffrey A; Trinh, Nguyen Thu Ngan; Beaudoin, Trevor; Desrosiers, Martin-Yvon; Rousseau, Simon; Nguyen, Dao; Brochiero, Emmanuelle

    2016-09-01

    Chronic Pseudomonas aeruginosa lung infections are associated with progressive epithelial damage and lung function decline. In addition to its role in tissue injury, the persistent presence of P. aeruginosa-secreted products may also affect epithelial repair ability, raising the need for new antivirulence therapies. The purpose of our study was to better understand the outcomes of P. aeruginosa exoproducts exposure on airway epithelial repair processes to identify a strategy to counteract their deleterious effect. We found that P. aeruginosa exoproducts significantly decreased wound healing, migration, and proliferation rates, and impaired the ability of directional migration of primary non-cystic fibrosis (CF) human airway epithelial cells. Impact of exoproducts was inhibited after mutations in P. aeruginosa genes that encoded for the quorum-sensing (QS) transcriptional regulator, LasR, and the elastase, LasB, whereas impact was restored by LasB induction in ΔlasR mutants. P. aeruginosa purified elastase also induced a significant decrease in non-CF epithelial repair, whereas protease inhibition with phosphoramidon prevented the effect of P. aeruginosa exoproducts. Furthermore, treatment of P. aeruginosa cultures with 4-hydroxy-2,5-dimethyl-3(2H)-furanone, a QS inhibitor, abrogated the negative impact of P. aeruginosa exoproducts on airway epithelial repair. Finally, we confirmed our findings in human airway epithelial cells from patients with CF, a disease featuring P. aeruginosa chronic respiratory infection. These data demonstrate that secreted proteases under the control of the LasR QS system impair airway epithelial repair and that QS inhibitors could be of benefit to counteract the deleterious effect of P. aeruginosa in infected patients.-Ruffin, M., Bilodeau, C., Maillé, É., LaFayette, S. L., McKay, G. A., Trinh, N. T. N., Beaudoin, T., Desrosiers, M.-Y., Rousseau, S., Nguyen, D., Brochiero, E. Quorum-sensing inhibition abrogates the deleterious impact

  18. Chromosomal organization and segregation in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Isabelle Vallet-Gely

    2013-05-01

    Full Text Available The study of chromosomal organization and segregation in a handful of bacteria has revealed surprising variety in the mechanisms mediating such fundamental processes. In this study, we further emphasized this diversity by revealing an original organization of the Pseudomonas aeruginosa chromosome. We analyzed the localization of 20 chromosomal markers and several components of the replication machinery in this important opportunistic γ-proteobacteria pathogen. This technique allowed us to show that the 6.3 Mb unique circular chromosome of P. aeruginosa is globally oriented from the old pole of the cell to the division plane/new pole along the oriC-dif axis. The replication machinery is positioned at mid-cell, and the chromosomal loci from oriC to dif are moved sequentially to mid-cell prior to replication. The two chromosomal copies are subsequently segregated at their final subcellular destination in the two halves of the cell. We identified two regions in which markers localize at similar positions, suggesting a bias in the distribution of chromosomal regions in the cell. The first region encompasses 1.4 Mb surrounding oriC, where loci are positioned around the 0.2/0.8 relative cell length upon segregation. The second region contains at least 800 kb surrounding dif, where loci show an extensive colocalization step following replication. We also showed that disrupting the ParABS system is very detrimental in P. aeruginosa. Possible mechanisms responsible for the coordinated chromosomal segregation process and for the presence of large distinctive regions are discussed.

  19. Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

    DEFF Research Database (Denmark)

    Johansen, Helle Krogh; Gøtzsche, Peter C

    2015-01-01

    BACKGROUND: Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed. This is a......BACKGROUND: Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed....... This is an update of a previously published review. OBJECTIVES: To assess the effectiveness of vaccination against Pseudomonas aeruginosa in cystic fibrosis. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register using the terms vaccines AND pseudomonas (last search 30...... March 2015). We previously searched PubMed using the terms vaccin* AND cystic fibrosis (last search 30 May 2013). SELECTION CRITERIA: Randomised trials (published or unpublished) comparing Pseudomonas aeruginosa vaccines (oral, parenteral or intranasal) with control vaccines or no intervention in cystic...

  20. Pseudomonas aeruginosa exotoxin pyocyanin causes cystic fibrosis airway pathogenesis.

    Science.gov (United States)

    Caldwell, Charles C; Chen, Yi; Goetzmann, Holly S; Hao, Yonghua; Borchers, Michael T; Hassett, Daniel J; Young, Lisa R; Mavrodi, Dmitri; Thomashow, Linda; Lau, Gee W

    2009-12-01

    The cystic fibrosis (CF) airway bacterial pathogen Pseudomonas aeruginosa secretes multiple virulence factors. Among these, the redox active exotoxin pyocyanin (PCN) is produced in concentrations up to 100 mumol/L during infection of CF and other bronchiectatic airways. However, the contributions of PCN during infection of bronchiectatic airways are not appreciated. In this study, we demonstrate that PCN is critical for chronic infection in mouse airways and orchestrates adaptive immune responses that mediate lung damage. Wild-type FVBN mice chronically exposed to PCN developed goblet cell hyperplasia and metaplasia, airway fibrosis, and alveolar airspace destruction. Furthermore, after 12 weeks of exposure to PCN, mouse lungs down-regulated the expression of T helper (Th) type 1 cytokines and polarized toward a Th2 response. Cellular analyses indicated that chronic exposure to PCN profoundly increased the lung population of recruited macrophages, CD4(+) T cells, and neutrophils responsible for the secretion of these cytokines. PCN-mediated goblet cell hyperplasia and metaplasia required Th2 cytokine signaling through the Stat6 pathway. In summary, this study establishes that PCN is an important P. aeruginosa virulence factor capable of directly inducing pulmonary pathophysiology in mice, consistent with changes observed in CF and other bronchiectasis lungs.

  1. The crystal structure of SdsA1, an alkylsulfatase from Pseudomonas aeruginosa, defines a third class of sulfatases

    OpenAIRE

    Hagelueken, Gregor; Adams, Thorsten M.; Wiehlmann, Lutz; Widow, Ute; Kolmar, Harald; Tümmler, Burkhard; Heinz, Dirk W.; Schubert, Wolf-Dieter

    2006-01-01

    Pseudomonas aeruginosa is both a ubiquitous environmental bacterium and an opportunistic human pathogen. A remarkable metabolic versatility allows it to occupy a multitude of ecological niches, including wastewater treatment plants and such hostile environments as the human respiratory tract. P. aeruginosa is able to degrade and metabolize biocidic SDS, the detergent of most commercial personal hygiene products. We identify SdsA1 of P. aeruginosa as a secreted SDS hydrolase that allows the ba...

  2. Characterization of Pseudomonas aeruginosa PB112 (JN996498 ...

    African Journals Online (AJOL)

    Characterization of Pseudomonas aeruginosa PB112 (JN996498) isolated from infected Labeo bata (Hamilton) by 16S rRNA gene sequence analysis and fatty acid methyl ester (FAME) analysis. Somerita Panda, PK Bandyopadhyay, SN Chatterjee ...

  3. The Enzymes of the Ammonia Assimilation in Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Janssen, Dick B.; Camp, Huub J.M. op den; Leenen, Pieter J.M.; Drift, Chris van der

    1980-01-01

    Glutamine synthetase from Pseudomonas aeruginosa is regulated by repression/derepression of enzyme synthesis and by adenylylation/deadenylylation control. High levels of deadenylylated biosynthetically active glutamine synthetase were observed in cultures growing with limiting amounts of nitrogen

  4. Resistance patterns of Pseudomonas aeruginosa isolated from HIV ...

    African Journals Online (AJOL)

    negative bacilli in patients with impaired host defences emphasizes the need for information on the antibiotic susceptibility of the organisms that infects such patients. Pseudomonas aeruginosa are becoming increasingly resistant to ...

  5. Caenorhabditis elegans reveals novel Pseudomonas aeruginosa virulence mechanism

    NARCIS (Netherlands)

    Utari, Putri Dwi; Quax, Wim J.

    The susceptibility of Caenorhabditis elegans to different virulent phenotypes of Pseudomonas aeruginosa makes the worms an excellent model for studying host-pathogen interactions. Including the recently described liquid killing, five different killing assays are now available offering superb

  6. Sequencing and characterization of Pseudomonas aeruginosa phage JG004

    National Research Council Canada - National Science Library

    Garbe, Julia; Bunk, Boyke; Rohde, Manfred; Schobert, Max

    2011-01-01

    .... Pseudomonas aeruginosa. For an effective use of bacteriophages as antimicrobial agents, it is important to understand phage biology but also genes of the bacterial host essential for phage infection...

  7. Infectious conjunctivitis caused by Pseudomonas aeruginosa isolated from a bathroom

    National Research Council Canada - National Science Library

    Eguchi, Hiroshi; Miyamoto, Tatsuro; Kuwahara, Tomomi; Mitamura, Sayaka; Mitamura, Yoshinori

    2013-01-01

    .... The purpose of this report is to describe a case of suture-related conjunctivitis caused by Pseudomonas aeruginosa for which we identified the transmission route using pulsed-field gel electrophoresis (PFGE...

  8. Characterization of Glutamine-Requiring Mutants of Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Janssen, Dick B.; Joosten, Han M.L.J.; Herst, Patricia M.; Drift, Chris van der

    1982-01-01

    Revertants were isolated from a glutamine-requiring mutant of Pseudomonas aeruginosa PAO. One strain showed thermosensitive glutamine requirement and formed thermolabile glutamine synthetase, suggesting the presence of a mutation in the structural gene for glutamine synthetase. The mutation

  9. Isolation of chlorhexidine-resistant Pseudomonas aeruginosa from clinical lesions.

    OpenAIRE

    Nakahara, H; Kozukue, H

    1982-01-01

    The chlorhexidine resistance of 317 strains of Pseudomonas aeruginosa isolated from hospital patients was determined. The distribution pattern of their susceptibility to chlorhexidine clearly revealed two peaks, and the frequency of resistance to chlorhexidine was 84.2%.

  10. Hyperbaric oxygen sensitizes anoxic Pseudomonas aeruginosa biofilm to ciprofloxacin

    DEFF Research Database (Denmark)

    Kolpen, Mette; Lerche, Christian J; Kragh, Kasper Nørskov

    2017-01-01

    Chronic Pseudomonas aeruginosa lung infection is characterized by the presence of endobronchial antibiotic-tolerant biofilm subject to strong oxygen (O2) depletion due to the activity of surrounding polymorphonuclear leukocytes. The exact mechanisms affecting the antibiotic susceptibility of biof...

  11. Biodegradasi Petroleum dan Hidrokarbon Eikosana oleh Isolat Bakteri Pseudomonas aeruginosa

    OpenAIRE

    Faiqah Umar

    2015-01-01

    Biodegradation of petroleum and hydrocarbon eicosane by Pseudomonas aeruginosa isolate. Hydrocarbon are important environmental contaminants in soil and water. These compounds have a potential risk to human health, as many of them are carsinogenic and toxic to marine organisms such as diatome, gasthrophode, mussel, and fish. The purpose of this research was to know the ability of Pseudomonas aeruginosa to degradate the hydrocarbon (petroleum Hundill and eicosane) substrate. Growing test used ...

  12. The ability of virulence factor expression by Pseudomonas aeruginosa to predict clinical disease in hospitalized patients.

    Directory of Open Access Journals (Sweden)

    Michel Ledizet

    Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen that frequently causes hospital acquired colonization and infection. Accurate identification of host and bacterial factors associated with infection could aid treatment decisions for patients with P. aeruginosa cultured from clinical sites.We identified a prospective cohort of 248 hospitalized patients with positive P. aeruginosa cultures. Clinical data were analyzed to determine whether an individual met predefined criteria for infection versus colonization. P. aeruginosa isolates were tested for the expression of multiple phenotypes previously associated with virulence in animal models and humans. Logistic regression models were constructed to determine the degree of association between host and bacterial factors with P. aeruginosa infection of the bloodstream, lung, soft tissue and urinary tract.One host factor (i.e. diabetes mellitus, and one bacterial factor, a Type 3 secretion system positive phenotype, were significantly associated with P. aeruginosa infection in our cohort. Subgroup analysis of patients with P. aeruginosa isolated from the urinary tract revealed that the presence of a urinary tract catheter or stent was an additional factor for P. aeruginosa infection.Among hospitalized patients with culture-documented P. aeruginosa, infection is more likely to be present in those with diabetes mellitus and those harboring a Type 3 secretion positive bacterial strain.

  13. extracts of senna siamea (lam) on pseudomonas aeruginosa

    African Journals Online (AJOL)

    DR. AMINU

    2009-05-30

    May 30, 2009 ... convulsion in children (Alli – Smith, 2009). In an attempt to rationally identify which pathogen to screen, Pseudomonas aeruginosa was epidemiologically identified as the hardiest bacterium that constitutes problems to researchers and clinicians. As literature showed, the hardy nature of Ps aeruginosa is ...

  14. Pseudomonas aeruginosa burn wound infection in a dedicated ...

    African Journals Online (AJOL)

    Background. Pseudomonas aeruginosa infection is a major cause of morbidity in burns patients. There is a paucity of publications dealing with this infection in the paediatric population. We describe the incidence, microbiology and impact of P. aeruginosa infection in a dedicated paediatric burns unit. Methods.

  15. Ambroxol interferes with Pseudomonas aeruginosa quorum sensing.

    Science.gov (United States)

    Lu, Qi; Yu, Jialin; Yang, Xiqiang; Wang, Jiarong; Wang, Lijia; Lin, Yayin; Lin, Lihua

    2010-09-01

    The mucolytic agent ambroxol has been reported to interfere with the formation of Pseudomonas aeruginosa-derived biofilms in addition to reducing alginate production by undefined mechanisms. Since quorum sensing is a key regulator of virulence and biofilm formation, we examined the effects of ambroxol on P. aeruginosa PAO1 wild-type bacterial clearance rates, adhesion profiles and biofilm formation compared with the quorum sensing-deficient, double-mutant strains DeltalasR DeltarhlR and DeltalasI DeltarhlI. Data presented in this report demonstrated that ambroxol treatment reduced survival rates of the double-mutant strains compared with the wild-type strain in a dose-dependent manner even though the double-mutants had increased adhesion in the presence of ambroxol compared with the wild-type strain. The PAO1 wild-type strain produced a significantly thicker biofilm (21.64+/-0.57 microm) compared with the biofilms produced by the DeltalasR DeltarhlR (7.36+/-0.2 microm) and DeltalasI DeltarhlI (6.62+/-0.31 microm) isolates. Ambroxol treatment reduced biofilm thickness, increased areal porosity, and decreased the average diffusion distance and textual entropy of wild-type and double-mutant strains. However, compared with the double-mutant strains, the changes observed for the wild-type strain were more clearly defined. Finally, ambroxol exhibited significant antagonistic quorum-sensing properties, suggesting that it could be adapted for use clinically in the treatment of cystic fibrosis and to reduce biofilm formation and in the colonisation of indwelling devices. Copyright (c) 2010 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  16. Novel Targets for Treatment of Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Morten; Alhede, Maria; Bjarnsholt, Thomas

    2014-01-01

    Pseudomonas aeruginosa causes infection in all parts of the human body. The bacterium is naturally resistant to a wide range of antibiotics. In addition to resistance mechanisms such as efflux pumps, the ability to form aggregates, known as biofilm, further reduces Pseudomonas aeruginosa’s...

  17. Interleukin-18 impairs the pulmonary host response to Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Schultz, Marc J.; Knapp, Sylvia; Florquin, Sandrine; Pater, Jennie; Takeda, Kiyoshi; Akira, Shizuo; van der Poll, Tom

    2003-01-01

    Interleukin-18 (IL-18) is a potent cytokine with many different proinflammatory activities. To study the role of IL-18 in the pathogenesis of Pseudomonas pneumonia, IL-18-deficient (IL-18(-/-)) and wild-type mice were intranasally inoculated with Pseudomonas aeruginosa. IL-18 deficiency was

  18. Typing of Pseudomonas aeruginosa strains in Norwegian cystic fibrosis patients

    DEFF Research Database (Denmark)

    Fluge, G; Ojeniyi, B; Høiby, N

    2001-01-01

    OBJECTIVES: Typing of Pseudomonas aeruginosa isolates from Norwegian cystic fibrosis (CF) patients with chronic Pseudomonas lung infection in order to see whether cross-infection might have occurred. METHODS: Isolates from 60 patients were collected during the years 1994-98, and typed by pulsed...... between cystic fibrosis patients has occurred....

  19. Energetics of binary mixed culture of Pseudomonas aeruginosa and ...

    African Journals Online (AJOL)

    Bioenergetic analysis of the growth of the binary mixed culture (Pseudomonas aeruginosa and Pseudomonas fluorescence) on phenol chemostat culture was carried out. The data were checked for consistency using carbon and available electron balances. When more than the minimum number of variables are measured, ...

  20. Energetics of binary mixed culture of Pseudomonas aeruginosa and ...

    African Journals Online (AJOL)

    Jane

    2010-12-20

    Dec 20, 2010 ... Bioenergetic analysis of the growth of the binary mixed culture (Pseudomonas aeruginosa and. Pseudomonas fluorescence) on ... biological system is widely gaining recognition (Yang et al., 1984; Solomon et al., .... Thus, by application of the covariate adjustment technique. (Solomon et al., 1985, 1994) in ...

  1. [Effect on keratocyte-mediated collagen degradation by Pseudomonas aeruginosa].

    Science.gov (United States)

    Hao, J; Lu, Y; Jia, H; Liu, J; Xu, J; Zhang, R

    2000-01-01

    To study the pathogenesis of cornea melting (ulceration) by pseudomona (P) aeruginosa for instruction of clinical treatment. Type I collagen gels with or without suspended keratocytes were incubated for 24 hours under medium containing sterile P. aeruginosa culture broth. Native collagen fibrils were removed from the media by ultrafiltration. The ultrafiltrates were then hydrolyzed, and the amount of hydroxyproline was measured spectrophotometrically. The effect of a synthetic matrix metalloproteinase (MMP) inhibitor, Galardin, on collagen degradation was also examined. P. aeruginosa broth induced type I collagen gel degradation directly. In the presence of keratocytes, degradation by P. aeruginosa broth was enhanced. Galardin significantly reduced the amount of collagen degraded by P. aeruginosa culture broth, no matter keratocytes were present or not. P. aeruginosa culture broth directly degrades type I collagen and also increases keratocyte-mediated collagen degradation. The result is helpful to the clinical treatment of cornea melting caused by P. aeruginosa, and the mechanism should be further studied.

  2. Bioadsorption characteristics of Pseudomonas aeruginosa PAOI

    Directory of Open Access Journals (Sweden)

    Kőnig-Péter Anikó

    2014-01-01

    Full Text Available Biosorption of Cd(II and Pb(II ions from aqueous solution using lyophilized Pseudomonas aeruginosa (PAOI cells were observed under various experimental conditions. The effect of pH, initial metal concentration, equilibration time and temperature on bioadsorption was investigated. The optimum pH value for Pb(II adsorption was found to be 5.0, and for Cd(II 5.0 − 6.0. The Pb(II and Cd(II bioadsorption equilibrium were analyzed by using Freundlich and Langmuir model using nonlinear least-squares estimation. The experimental maximum uptake capacity of Pb(II and Cd(II was estimated to be 164 mg g-1 and 113 mg g-1, respectively. For biosorption kinetic study the pseudo second-order kinetic model was applied at various temperatures. The temperature had no significant effect on Pb(II bioadsorption. In case of Cd(II bioadsorption the adsorbed amount decreased with increasing temperature.

  3. Effects of ginseng on Pseudomonas aeruginosa motility and biofilm formation

    DEFF Research Database (Denmark)

    Wu, Hong; Lee, Baoleri; Yang, Liang

    2011-01-01

    Biofilm-associated chronic Pseudomonas aeruginosa lung infections in patients with cystic fibrosis are virtually impossible to eradicate with antibiotics because biofilm-growing bacteria are highly tolerant to antibiotics and host defense mechanisms. Previously, we found that ginseng treatments...... protected animal models from developing chronic lung infection by P. aeruginosa. In the present study, the effects of ginseng on the formation of P. aeruginosa biofilms were further investigated in vitro and in vivo. Ginseng aqueous extract at concentrations of 0.5-2.0% did not inhibit the growth of P....... aeruginosa, but significantly prevented P. aeruginosa from forming biofilm. Exposure to 0.5% ginseng aqueous extract for 24 h destroyed most 7-day-old mature biofilms formed by both mucoid and nonmucoid P. aeruginosa strains. Ginseng treatment enhanced swimming and twitching motility, but reduced swarming...

  4. Effects of ambroxol on alginate of mature Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Li, Fang; Yu, Jialin; Yang, Hua; Wan, Zhenyan; Bai, Dan

    2008-07-01

    Biofilm-forming bacteria Pseudomonas aeruginosa is a common pathogen in mechanically ventilated newborns, which can cause life-threatening infections. Alginate of mucoid Pseudomonas aeruginosa biofilms is considered an important virulence factor which contributes to the resistance to antibiotics. Traditionally, ambroxol is widely used in newborns with lung problems as a mucolytic agent and antioxidant agent as well. And there are few studies that demonstrated the anti-biofilm activity of ambroxol. In this study, we found that ambroxol can affect the structure of mucoid Pseudomonas aeruginosa biofilms. Further, we found that ambroxol reduces the production of alginate, the expression of the important genes and the activity of key enzyme guanosine diphospho-D-mannose dehydrogenase (GDP-mannose dehydrogenase; GMD) which were involved in alginate biosynthesis.

  5. Experimental Pseudomonas aeruginosa mediated rhino sinusitis in mink

    DEFF Research Database (Denmark)

    Kirkeby, S.; Hammer, A. S.; Høiby, N.

    2017-01-01

    The nasal and sinus cavities in children may serve as reservoirs for microorganisms that cause recurrent and chronic lung infections. This study evaluates whether the mink can be used as an animal model for studying Pseudomonas aeruginosa mediated rhino-sinusitis since there is no suitable...... in the infected mink shows features of carbohydrate expression comparable to what has been described in the respiratory system after Pseudomonas aeruginosa infection in humans. It is suggested that the mink is suitable for studying Pseudomonas aeruginosa mediated rhino-sinusitis....... traditional animal model for this disease. Nasal tissue samples from infected and control mink were fixed in formalin, demineralized, and embedded in paraffin. A histological examination of sections from the infected animals revealed disintegration of the respiratory epithelium lining the nasal turbinates...

  6. Pseudomonas aeruginosa: an uncommon cause of diabetic foot infection.

    Science.gov (United States)

    Young, Heather; Knepper, Bryan; Hernandez, Whitney; Shor, Asaf; Bruntz, Merribeth; Berg, Chrystal; Price, Connie S

    2015-03-01

    Pseudomonas aeruginosa has traditionally been considered a common pathogen in diabetic foot infection (DFI), yet the 2012 Infectious Diseases Society of America guideline for DFI states that "empiric therapy directed at P aeruginosa is usually unnecessary." The objective of this study was to evaluate the frequency of P aeruginosa isolated from bone or tissue cultures from patients with DFI. This study is a cross-sectional survey of diabetic patients presenting with a foot infection to an urban county hospital between July 1, 2012, and December 31, 2013. All of the patients had at least one debridement procedure during which tissue or bone cultures from operative or bedside debridements were obtained. The χ(2) test and the t test of means were used to determine relationships between variables and the frequency of P aeruginosa in culture. The median number of bacteria isolated from DFI was two. Streptococcus spp and Staphylococcus aureus were the most commonly isolated organisms; P aeruginosa was isolated in only five of 112 patients (4.5%). The presence of P aeruginosa was not associated with the patient's age, glycosylated hemoglobin level, tobacco abuse, the presence of osteomyelitis, a prescription for antibiotic drugs in the preceding 3 months, or the type of operative procedure. Pseudomonas aeruginosa was an infrequent isolate from DFI in this urban, underserved diabetic population. The presence of P aeruginosa was not associated with any measured risk factors. By introducing a clinical practice guideline, we hope to discourage frontline providers from using routine antipseudomonal antibiotic drugs for DFI.

  7. The Pseudomonas aeruginosa PSL polysaccharide is a social but noncheatable trait in biofilms

    DEFF Research Database (Denmark)

    Irie, Yasuhiko; Roberts, Aled E.L.; Kragh, Kasper N.

    2017-01-01

    Extracellular polysaccharides are compounds secreted by microorganisms into the surrounding environment, and they are important for surface attachment and maintaining structural integrity within biofilms. The social nature of many extracellular polysaccharides remains unclear, and it has been...... suggested that they could function as either cooperative public goods or as traits that provide a competitive advantage. Here, we empirically tested the cooperative nature of the PSL polysaccharide, which is crucial for the formation of biofilms in Pseudomonas aeruginosa. We show that (i) PSL...

  8. The effect of pseudomonas exotoxin A on cytokine production in whole blood exposed to Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Schultz, M. J.; Speelman, P.; Zaat, S. A.; Hack, C. E.; van Deventer, S. J.; van der Poll, T.

    2000-01-01

    To determine the effect of Pseudomonas aeruginosa exotoxin A (P-ExA) on cytokine production, we studied cytokine release induced by heat-killed P. aeruginosa (HKPA) in human whole blood in the presence or absence of P-ExA. P-ExA (0.01-1 microgram ml(-1)) caused a dose-dependent decrease in

  9. N-acetylcysteine inhibit biofilms produced by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Liu Youning

    2010-05-01

    Full Text Available Abstract Background Pseudomonas aeruginosa is a common pathogen in chronic respiratory tract infections. It typically makes a biofilm, which makes treatment of these infections difficult. In this study, we investigated the inhibitory effects of N-acetylcysteine (NAC on biofilms produced by P. aeruginosa. Results We found that minimum inhibitory concentrations (MICs of NAC for most isolates of P. aeruginosa were 10 to 40 mg/ml, the combination of NAC and ciprofloxacin (CIP demonstrated either synergy (50% or no interaction (50% against the P. aeruginosa strains. NAC at 0.5 mg/ml could detach mature P. aeruginosa biofilms. Disruption was proportional to NAC concentrations, and biofilms were completely disrupted at 10 mg/ml NAC. Analysis using COMSTAT software also showed that PAO1 biofilm biomass decreased and its heterogeneity increased as NAC concentration increased. NAC and ciprofloxacin showed significant killing of P. aeruginosa in biofilms at 2.5 mg/ml and > 2 MIC, respectively (p p P. aeruginosa also decreased by 27.64% and 44.59% at NAC concentrations of 0.5 mg/ml and 1 mg/ml. Conclusions NAC has anti-bacterial properties against P. aeruginosa and may detach P. aeruginosa biofilms. Use of NAC may be a new strategy for the treatment of biofilm-associated chronic respiratory infections due to P. aeruginosa, although it would be appropriate to conduct clinical studies to confirm this.

  10. Pseudomonas aeruginosa Bloodstream Infection: Importance of Appropriate Initial Antimicrobial Treatment

    OpenAIRE

    Micek, Scott T; Lloyd, Ann E.; David J. Ritchie; Reichley, Richard M.; Fraser, Victoria J.; Kollef, Marin H

    2005-01-01

    Pseudomonas aeruginosa bloodstream infection is a serious infection with significant patient mortality and health-care costs. Nevertheless, the relationship between initial appropriate antimicrobial treatment and clinical outcomes is not well established. This study was a retrospective cohort analysis employing automated patient medical records and the pharmacy database at Barnes-Jewish Hospital. Three hundred five patients with P. aeruginosa bloodstream infection were identified over a 6-yea...

  11. Pyochelin Potentiates the Inhibitory Activity of Gallium on Pseudomonas aeruginosa

    Science.gov (United States)

    Frangipani, Emanuela; Bonchi, Carlo; Minandri, Fabrizia; Imperi, Francesco

    2014-01-01

    Gallium (Ga) is an iron mimetic that has successfully been repurposed for antibacterial chemotherapy. To improve the antibacterial potency of Ga on Pseudomonas aeruginosa, the effect of complexation with a variety of siderophores and synthetic chelators was tested. Ga complexed with the pyochelin siderophore (at a 1:2 ratio) was more efficient than Ga(NO3)3 in inhibiting P. aeruginosa growth, and its activity was dependent on increased Ga entrance into the cell through the pyochelin translocon. PMID:24957826

  12. Development of potent inhibitors of pyocyanin production in Pseudomonas aeruginosa.

    Science.gov (United States)

    Miller, Laura C; O'Loughlin, Colleen T; Zhang, Zinan; Siryaporn, Albert; Silpe, Justin E; Bassler, Bonnie L; Semmelhack, Martin F

    2015-02-12

    The development of new approaches for the treatment of antimicrobial-resistant infections is an urgent public health priority. The Pseudomonas aeruginosa pathogen, in particular, is a leading source of infection in hospital settings, with few available treatment options. In the context of an effort to develop antivirulence strategies to combat bacterial infection, we identified a series of highly effective small molecules that inhibit the production of pyocyanin, a redox-active virulence factor produced by P. aeruginosa. Interestingly, these new antagonists appear to suppress P. aeruginosa virulence factor production through a pathway that is independent of LasR and RhlR.

  13. Gene expression in Pseudomonas aeruginosa swarming motility

    Directory of Open Access Journals (Sweden)

    Déziel Eric

    2010-10-01

    Full Text Available Abstract Background The bacterium Pseudomonas aeruginosa is capable of three types of motilities: swimming, twitching and swarming. The latter is characterized by a fast and coordinated group movement over a semi-solid surface resulting from intercellular interactions and morphological differentiation. A striking feature of swarming motility is the complex fractal-like patterns displayed by migrating bacteria while they move away from their inoculation point. This type of group behaviour is still poorly understood and its characterization provides important information on bacterial structured communities such as biofilms. Using GeneChip® Affymetrix microarrays, we obtained the transcriptomic profiles of both bacterial populations located at the tip of migrating tendrils and swarm center of swarming colonies and compared these profiles to that of a bacterial control population grown on the same media but solidified to not allow swarming motility. Results Microarray raw data were corrected for background noise with the RMA algorithm and quantile normalized. Differentially expressed genes between the three conditions were selected using a threshold of 1.5 log2-fold, which gave a total of 378 selected genes (6.3% of the predicted open reading frames of strain PA14. Major shifts in gene expression patterns are observed in each growth conditions, highlighting the presence of distinct bacterial subpopulations within a swarming colony (tendril tips vs. swarm center. Unexpectedly, microarrays expression data reveal that a minority of genes are up-regulated in tendril tip populations. Among them, we found energy metabolism, ribosomal protein and transport of small molecules related genes. On the other hand, many well-known virulence factors genes were globally repressed in tendril tip cells. Swarm center cells are distinct and appear to be under oxidative and copper stress responses. Conclusions Results reported in this study show that, as opposed to

  14. A Pseudomonas aeruginosa toxin that hijacks the host ubiquitin proteolytic system.

    Directory of Open Access Journals (Sweden)

    Jennifer M Bomberger

    2011-03-01

    Full Text Available Pseudomonas aeruginosa (P. aeruginosa is an opportunistic pathogen chronically infecting the lungs of patients with chronic obstructive pulmonary disease (COPD, pneumonia, cystic fibrosis (CF, and bronchiectasis. Cif (PA2934, a bacterial toxin secreted in outer membrane vesicles (OMV by P. aeruginosa, reduces CFTR-mediated chloride secretion by human airway epithelial cells, a key driving force for mucociliary clearance. The aim of this study was to investigate the mechanism whereby Cif reduces CFTR-mediated chloride secretion. Cif redirected endocytosed CFTR from recycling endosomes to lysosomes by stabilizing an inhibitory effect of G3BP1 on the deubiquitinating enzyme (DUB, USP10, thereby reducing USP10-mediated deubiquitination of CFTR and increasing the degradation of CFTR in lysosomes. This is the first example of a bacterial toxin that regulates the activity of a host DUB. These data suggest that the ability of P. aeruginosa to chronically infect the lungs of patients with COPD, pneumonia, CF, and bronchiectasis is due in part to the secretion of OMV containing Cif, which inhibits CFTR-mediated chloride secretion and thereby reduces the mucociliary clearance of pathogens.

  15. Chronic Pseudomonas aeruginosa lung infection in normal and athymic rats

    DEFF Research Database (Denmark)

    Johansen, H K; Espersen, F; Pedersen, S S

    1993-01-01

    We have compared a chronic lung infection with Pseudomonas aeruginosa embedded in alginate beads in normal and athymic rats with an acute infection with free live P. aeruginosa bacteria. The following parameters were observed and described: mortality, macroscopic and microscopic pathologic changes......, and antibody responses. The rats challenged with P. aeruginosa alginate beads experienced a generally more severe lung pathology and the antibody responses were more homogeneous with less dispersion as compared to the rats having free live P. aeruginosa bacteria. In general, manifestations were more severe...... in the athymic rats compared to the normal rats. It is, however, notable that the athymic rats developed similar microscopic lung manifestations as the normal rats when given a large number of P. aeruginosa in the beads, with dense accumulation of neutrophil granulocytes and microcolonies comparable...

  16. Aspergillus triggers phenazine production in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Jensen, Britt Guillaume; Jelsbak, Lars; Søndergaard, Ib

    Aspergillus species. Methods: A suspension of fungal spores was streaked onto WATM agar plates. After 24 hours incubation at 37 °C, a P. aeruginosa overnight culture was streaked out perpendicular to the fungal streak. The plates were incubated at 37 °C for five days, examined and plugs were extracted...... for HPLC-DAD and HPLC-DAD-MS analysis. Results: P. aeruginosa PAO1 suppressed growth of A. fumigatus, A. niger, A. flavus, A. oryzae, A. terreus and Emericella nidulans. HPLC and HPLC-DAD-MS results showed an increase in phenazine-1-carboxylic acid and phenazine-1-carboxamide production by P. aeruginosa...

  17. Suppression of Aspergillus by Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Jensen, Britt Guillaume; Jelsbak, Lars; Søndergaard, Ib

    culture plates. After 24 hours incubation at 37 °C, a P. aeruginosa overnight culture diluted to 108 CFU/ml was streaked out perpendicular to the fungal streak. The plates were incubated at 37 °C for 5 days, examined and plugs were extracted for HPLC and LC-DAD-MS analysis. Results: P. aeruginosa PAO1...... suppressed growth of A. fumigatus, A. niger, A. flavus, A. oryzae, A. terreus and E. nidulans. HPLC and LC-DAD-MS results showed an increase in phenazine-1-carboxylic acid and phenazine-1-carboxamide production by P. aeruginosa in the contact area of Aspergillus. Different quinolones were also identified...

  18. Elastase Deficiency Phenotype of Pseudomonas aeruginosa Canine Otitis Externa Isolates

    OpenAIRE

    Petermann, Shana R.; Doetkott, Curt; Rust, Lynn

    2001-01-01

    Pseudomonas aeruginosa veterinary isolates were assayed for elastase and total matrix protease activity. The elastase activity of canine ear isolates was much less than that of strain PAO1 and that of all other veterinary isolates (P < 0.0001). The results indicate that canine ear isolates have a distinct elastase phenotype.

  19. An update on Pseudomonas aeruginosa biofilm formation, tolerance, and dispersal

    DEFF Research Database (Denmark)

    Harmsen, Morten; Yang, Liang; Pamp, Sünje Johanna

    2010-01-01

    We review the recent advances in the understanding of the Pseudomonas aeruginosa biofilm lifestyle from studies using in vitro laboratory setups such as flow chambers and microtiter trays. Recent work sheds light on the role of nutrients, motility, and quorum sensing in structure formation in P. ...

  20. an tibiotic resistance trend of pseudomonas aeruginosa'in port

    African Journals Online (AJOL)

    AN TIBIOTIC RESISTANCE TREND OF PSEUDOMONAS AERUGINOSA'IN PORT. HARCOURT oaursca. 0. K}. ONYEJEPU, N 1. 1. Department of Medical Microbiology and Parasitology. University of Port Harcourt Teaching Hospital. Port Harcourt. 2. Nigerian Institute of Medical Research. 6 Edmond Crescent, Yabl. Lagos.

  1. Induction of beta-lactamase production in Pseudomonas aeruginosa biofilm

    DEFF Research Database (Denmark)

    Giwercman, B; Jensen, E T; Høiby, N

    1991-01-01

    Imipenem induced high levels of beta-lactamase production in Pseudomonas aeruginosa biofilms. Piperacillin also induced beta-lactamase production in these biofilms but to a lesser degree. The combination of beta-lactamase production with other protective properties of the biofilm mode of growth...

  2. Heavy Metal uptake Potentials of Pseudomonas aeruginosa and ...

    African Journals Online (AJOL)

    Uptake of heavy metals, silver and cadmium by Pseudomonas aeruginosa (a Gram negative bacterium) and Micrococcus luteus (a Gram positive bacterium) was investigated in Cadmium and Silver stock solution using ion selective electrodes. Silver and cadmium uptake by the two organisms was described by Langmuir ...

  3. Dechlorination of 1,2– dichloroethane by Pseudomonas aeruginosa ...

    African Journals Online (AJOL)

    As part of our attempt at isolating and stocking some indigenous microbial species, we isolated a bacterium from a waste dumpsite with appreciable dechlorination activity. 16S rDNA profiling revealed the isolate to be a strain of Pseudomonas aeruginosa and the sequence has been deposited in the NCBI nucleotide ...

  4. Antibiotic sensitivity of isolates of Pseudomonas aeruginosa in ...

    African Journals Online (AJOL)

    The pattern of antibiotic sensitivity of 229 clinical isolates of Pseudomonas aeruginosa isolated between June 1998 and May 2000 at the University of Nigeria Teaching Hospital (UNTH) Enugu was studied. The isolates were recovered from various clinical specimens by culturing on standard media viz: blood agar, ...

  5. Rhamnolipid stimulates uptake of hydrophobic compounds by Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Noordman, WH; Janssen, DB

    The biodegradation of hexadecane by five biosurfactant-producing bacterial strains (Pseudomonas aeruginosa UG2, Acinetobacter calcoaceticus RAG1, Rhodococcus erythropolis DSM 43066, R. erythropolis ATCC 19558, and strain BCG112) was determined in the presence and absence of exogenously added

  6. Isolation and characterization of gallium resistant Pseudomonas aeruginosa mutants

    NARCIS (Netherlands)

    García-Contreras, R; Lira-Silva, E; Jasso-Chávez, R; Hernández-González, I.L.; Maeda, T.; Hashimoto, T.; Boogerd, F.C.; Sheng, L; Wood, TK; Moreno-Sánchez, R

    2013-01-01

    Pseudomonas aeruginosa PA14 cells resistant to the novel antimicrobial gallium nitrate (Ga) were developed using transposon mutagenesis and by selecting spontaneous mutants. The mutants showing the highest growth in the presence of Ga were selected for further characterization. These mutants showed

  7. Decrease of Pseudomonas aeruginosa biofilm formation by food waste materials

    Czech Academy of Sciences Publication Activity Database

    Maděrová, Z.; Horská, K.; Kim, S.-R.; Lee, Ch.-H.; Pospíšková, K.; Šafaříková, Miroslava; Šafařík, Ivo

    2016-01-01

    Roč. 73, č. 9 (2016), s. 2143-2149 ISSN 0273-1223 Institutional support: RVO:60077344 Keywords : biofilm * food waste materials * magnetic spent grain * Pseudomonas aeruginosa Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.197, year: 2016

  8. dichloroethane by Pseudomonas aeruginosa OK1 isolated from a ...

    African Journals Online (AJOL)

    Administrator

    chlorinated organics such as monochloroacetic acid, trichloroacetic acid, dichloromethane, trichloromethane and tetrachloromethane at pH 7.5 and 9.0. Optimum temperature for dehalogenase activity against 1, 2 – DCE was 35oC. Key words: Dechlorination, 16S rDNA, bioremediation, Pseudomonas aeruginosa OK1.

  9. High Temperature Induced Antibiotic Sensitivity in Pseudomonas aeruginosa.

    Science.gov (United States)

    1984-08-01

    aeruginosa ATCC 9027 was maintained on Pseudomonas P agar slants (Difco Laboratories, Detroit, MI.). The organism was cultivated at 37°C or 46°C in a proteose...Studies on the permeability change produced in coliform bacteria by ethylene diamine tetracetate. J. Biol. Chem. 243: 2372 - 2380. 7. 9. Lowry, O.H., N.J

  10. Virulence Factors of Pseudomonas aeruginosa Induce Both the Unfolded Protein and Integrated Stress Responses in Airway Epithelial Cells

    NARCIS (Netherlands)

    van 't Wout, Emily F A; van Schadewijk, Annemarie; van Boxtel, Ria; Dalton, Lucy E; Clarke, Hanna J; Tommassen, J.P.M.; Marciniak, Stefan J; Hiemstra, Pieter S

    Pseudomonas aeruginosa infection can be disastrous in chronic lung diseases such as cystic fibrosis and chronic obstructive pulmonary disease. Its toxic effects are largely mediated by secreted virulence factors including pyocyanin, elastase and alkaline protease (AprA). Efficient functioning of the

  11. Subversion of mucosal barrier polarity by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Joanne eEngel

    2011-05-01

    Full Text Available The lumenal surfaces of human body are lined by a monolayer of epithelia that together with mucus secreting cells and specialized immune cells form the mucosal barrier. This barrier is one of the most fundamental components of the innate immune system, protecting organisms from the vast environmental microbiota. The mucosal epithelium is comprised of polarized epithelial cells with distinct apical and basolateral surfaces that are defined by unique set of protein and lipid composition and are separated by tight junctions. The apical surface serves as a barrier to the outside world and is specialized for the exchange of materials with the lumen. The basolateral surface is adapted for interaction with other cells and for exchange with the bloodstream. A wide network of proteins and lipids regulates the formation and maintenance of the epithelium polarity. Many human pathogens have evolved virulence mechanisms that target this network and interfere with epithelial polarity to enhance binding to the apical surface, enter into cells, and/or cross the mucosal barrier. This review highlights recent advances in our understanding of how Pseudomonas aeruginosa, an important opportunistic human pathogen that preferentially infects damaged epithelial tissues, exploits the epithelial cell polarization machinery to enhance infection.

  12. Infections with Pseudomonas aeruginosa in Charcot arthropathy of the foot.

    Science.gov (United States)

    Illgner, Ulrich; Uekoetter, Andreas; Runge, Sabrina; Wetz, Hans Henning

    2013-02-01

    Patients with Charcot arthropathy present a high risk for ulcers with secondary bone infection. Infections with Pseudomonas aeruginosa represent a severe threat to the patients. We hypothesized that infections with P aeruginosa result in a longer stay in hospital and more operations than infections with other bacteria. All patients who underwent surgery for Charcot arthropathy of the feet between 1996 and 2006 (n = 205) in our clinic were included. The duration of hospitalization and number of surgeries for infections due to methicillin-resistant Staphylococcus aureus (MRSA) versus P aeruginosa were compared to infections with other bacteria. All patients were scanned for MRSA and were isolated when tested positive and treated according to a defined algorithm. Seventy-nine intraoperative samples exhibited bacterial growth: 12 cases of MRSA, 14 cases of P aeruginosa, and 53 case of other bacteria. Patients with deep infections due to P aeruginosa stayed significantly longer in the hospital (52 vs 35 days, P < .041) and needed significantly more surgery (1.71 vs 1.28 surgeries, P < .027). There was no significant difference between patients with MRSA infections and those without MRSA or P aeruginosa. Infections with P aeruginosa resulted in more surgeries and a longer stay in the hospital. Early debridement is the basic treatment. A specific algorithm for isolation and operative and antibiotic treatment for P aeruginosa infections is proposed similar to an algorithm for MRSA that has been shown to be successful. Level IV, retrospective case Series.

  13. Impact of Silver Nanoparticle Transformation on Pseudomonas aeruginosa GFP Biofilm

    Science.gov (United States)

    Adegboye, Temitope Azeezat

    Silver nanoparticles (Ag NP) undergo transformations when released into the environment and often the transformed nanoparticles exhibit different behavior from the pristine analog. It is important to understand the influence of Ag NP transformation (particularly sulfidation) on its potential impacts in order to determine the effects of environmental transformation on biofilms. The goal of our study was to investigate interactions of polyvinylpyrrolidone-capped (PVP) pristine and transformed Ag NP (30 - 50 nm particle size) with bacterial biofilm to assess their impacts on biofilm communities. In this study, Pseudomonas aeruginosa GFP (ATCCRTM 10145GFP(TM)) biofilms were subjected to similar concentrations of pristine- Ag NP and transformed- Ag2S NP under environmentally relevant conditions. Residual concentrations of dissolved silver and NP after exposure to biofilms were evaluated by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy) analysis. The morphological properties of Pseudomonas aeruginosa GFP (P. aeruginosa) biofilms after exposure to both forms of silver nanoparticles were characterized by cell viability studies (using microplate reader and live/dead assay) and scanning electron microscopy (SEM). We also analyzed the distribution and size of investigated silver nanoparticles within P.aeruginosa biofilms using SEM coupled with EDS. Here, we report that transformed silver nanoparticle (Ag2S NP) exhibit reduced biofilm inactivation effects against P. aeruginosa biofilms compared to its pristine form (Ag NP). This result could be explained by a lower uptake of Ag2S nanoparticle by P. aeruginosa biofilms demonstrated by ICP-AES and SEM/EDS analysis.

  14. Label-free molecular imaging of bacterial communities of the opportunistic pathogen Pseudomonas aeruginosa

    Science.gov (United States)

    Baig, Nameera; Polisetti, Sneha; Morales-Soto, Nydia; Dunham, Sage J. B.; Sweedler, Jonathan V.; Shrout, Joshua D.; Bohn, Paul W.

    2016-09-01

    Biofilms, such as those formed by the opportunistic human pathogen Pseudomonas aeruginosa are complex, matrix enclosed, and surface-associated communities of cells. Bacteria that are part of a biofilm community are much more resistant to antibiotics and the host immune response than their free-floating counterparts. P. aeruginosa biofilms are associated with persistent and chronic infections in diseases such as cystic fibrosis and HIV-AIDS. P. aeruginosa synthesizes and secretes signaling molecules such as the Pseudomonas quinolone signal (PQS) which are implicated in quorum sensing (QS), where bacteria regulate gene expression based on population density. Processes such as biofilms formation and virulence are regulated by QS. This manuscript describes the powerful molecular imaging capabilities of confocal Raman microscopy (CRM) and surface enhanced Raman spectroscopy (SERS) in conjunction with multivariate statistical tools such as principal component analysis (PCA) for studying the spatiotemporal distribution of signaling molecules, secondary metabolites and virulence factors in biofilm communities of P. aeruginosa. Our observations reveal that the laboratory strain PAO1C synthesizes and secretes 2-alkyl-4-hydroxyquinoline N-oxides and 2-alkyl-4-hydroxyquinolones in high abundance, while the isogenic acyl homoserine lactone QS-deficient mutant (ΔlasIΔrhlI) strain produces predominantly 2-alkyl-quinolones during biofilm formation. This study underscores the use of CRM, along with traditional biological tools such as genetics, for studying the behavior of microbial communities at the molecular level.

  15. Intramolecular electron transfer in Pseudomonas aeruginosa cd(1) nitrite reductase

    DEFF Research Database (Denmark)

    Farver, Ole; Brunori, Maurizio; Cutruzzolà, Francesca

    2009-01-01

    The cd(1) nitrite reductases, which catalyze the reduction of nitrite to nitric oxide, are homodimers of 60 kDa subunits, each containing one heme-c and one heme-d(1). Heme-c is the electron entry site, whereas heme-d(1) constitutes the catalytic center. The 3D structure of Pseudomonas aeruginosa...... is controlling this internal ET step. In this study we have investigated the internal ET in the wild-type and His369Ala mutant of P. aeruginosa nitrite reductases and have observed similar cooperativity to that of the Pseudomonas stutzeri enzyme. Heme-c was initially reduced, in an essentially diffusion...... nitrite reductase has been determined in both fully oxidized and reduced states. Intramolecular electron transfer (ET), between c and d(1) hemes is an essential step in the catalytic cycle. In earlier studies of the Pseudomonas stutzeri enzyme, we observed that a marked negative cooperativity...

  16. Pseudomonas aeruginosa-associated Diarrheal Diseases in Children.

    Science.gov (United States)

    Chuang, Chih-Hsien; Janapatla, Rajendra Prasad; Wang, Yi-Hsin; Chang, Hsin-Ju; Huang, Yhu-Chering; Lin, Tzou-Yien; Chiu, Cheng-Hsun

    2017-12-01

    The gastrointestinal tract is not the common infection site of Pseudomonas aeruginosa. The role of P. aeruginosa as a causative agent for diarrhea in children without preexisting disease is controversial. From 2003 to 2012, we reviewed the records of 259 diarrheal patients less than 5 years of age whose stool culture grew P. aeruginosa. Virulence phenotypes of bacterial isolates were determined in vitro, including cytotoxicity, penetration and adherence to epithelial cells. The presence of P. aeruginosa in children with diarrhea less than 5 years old is 0.91%. P. aeruginosa-associated diarrheal diseases were classified into 4 groups: Shanghai fever (enteric infection and sepsis) (5%), P. aeruginosa enterocolitis (15%), P. aeruginosa-related diarrhea (19%) and antibiotic-associated diarrhea (43%). The remaining patients had coinfection with other pathogens (18%). Shanghai fever was the most severe enteric disease with invasive infection and complications. The clinical features of P. aeruginosa enterocolitis were prolonged fever with bloody or mucoid diarrhea mimicking bacterial enterocolitis. The clinical features of P. aeruginosa-related diarrhea and antibiotic-associated diarrhea were similar to viral or toxin-mediated diarrhea. Compared with other P. aeruginosa-associated diarrheal diseases, patients with Shanghai fever were younger, usually infants, and the characteristic laboratory findings included leukopenia, thrombocytopenia, high C-reactive protein, hyponatremia and hyperglycemia. Except for Shanghai fever, antibiotic treatment is not recommended. Isolates from Shanghai fever were more cytotoxic and adherent than isolates from uncomplicated diarrheal patients. P. aeruginosa could be an enteric pathogen even in healthy children. Young age and highly virulent bacterial strains were risk factors for Shanghai fever.

  17. Acquisition and Role of Molybdate in Pseudomonas aeruginosa

    Science.gov (United States)

    Pederick, Victoria G.; Eijkelkamp, Bart A.; Ween, Miranda P.; Begg, Stephanie L.; Paton, James C.

    2014-01-01

    In microaerophilic or anaerobic environments, Pseudomonas aeruginosa utilizes nitrate reduction for energy production, a process dependent on the availability of the oxyanionic form of molybdenum, molybdate (MoO42−). Here, we show that molybdate acquisition in P. aeruginosa occurs via a high-affinity ATP-binding cassette permease (ModABC). ModA is a cluster D-III solute binding protein capable of interacting with molybdate or tungstate oxyanions. Deletion of the modA gene reduces cellular molybdate concentrations and results in inhibition of anaerobic growth and nitrate reduction. Further, we show that conditions that permit nitrate reduction also cause inhibition of biofilm formation and an alteration in fatty acid composition of P. aeruginosa. Collectively, these data highlight the importance of molybdate for anaerobic growth of P. aeruginosa and reveal novel consequences of nitrate reduction on biofilm formation and cell membrane composition. PMID:25172858

  18. Pseudomonas aeruginosa in premise plumbing of large buildings.

    Science.gov (United States)

    Bédard, Emilie; Prévost, Michèle; Déziel, Eric

    2016-12-01

    Pseudomonas aeruginosa is an opportunistic bacterial pathogen that is widely occurring in the environment and is recognized for its capacity to form or join biofilms. The present review consolidates current knowledge on P. aeruginosa ecology and its implication in healthcare facilities premise plumbing. The adaptability of P. aeruginosa and its capacity to integrate the biofilm from the faucet and the drain highlight the role premise plumbing devices can play in promoting growth and persistence. A meta-analysis of P. aeruginosa prevalence in faucets (manual and electronic) and drains reveals the large variation in device positivity reported and suggest the high variability in the sampling approach and context as the main reason for this variation. The effects of the operating conditions that prevail within water distribution systems (disinfection, temperature, and hydraulic regime) on the persistence of P. aeruginosa are summarized. As a result from the review, recommendations for proactive control measures of water contamination by P. aeruginosa are presented. A better understanding of the ecology of P. aeruginosa and key influencing factors in premise plumbing are essential to identify culprit areas and implement effective control measures. © 2016 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  19. Interactions between Neutrophils and Pseudomonas aeruginosa in Cystic Fibrosis

    Science.gov (United States)

    Rada, Balázs

    2017-01-01

    Cystic fibrosis (CF) affects 70,000 patients worldwide. Morbidity and mortality in CF is largely caused by lung complications due to the triad of impaired mucociliary clearance, microbial infections and chronic inflammation. Cystic fibrosis airway inflammation is mediated by robust infiltration of polymorphonuclear neutrophil granulocytes (PMNs, neutrophils). Neutrophils are not capable of clearing lung infections and contribute to tissue damage by releasing their dangerous cargo. Pseudomonas aeruginosa is an opportunistic pathogen causing infections in immunocompromised individuals. P. aeruginosa is a main respiratory pathogen in CF infecting most patients. Although PMNs are key to attack and clear P. aeruginosa in immunocompetent individuals, PMNs fail to do so in CF. Understanding why neutrophils cannot clear P. aeruginosa in CF is essential to design novel therapies. This review provides an overview of the antimicrobial mechanisms by which PMNs attack and eliminate P. aeruginosa. It also summarizes current advances in our understanding of why PMNs are incapable of clearing P. aeruginosa and how this bacterium adapts to and resists PMN-mediated killing in the airways of CF patients chronically infected with P. aeruginosa. PMID:28282951

  20. Dynorphin activates quorum sensing quinolone signaling in Pseudomonas aeruginosa.

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    Olga Zaborina

    2007-03-01

    Full Text Available There is now substantial evidence that compounds released during host stress directly activate the virulence of certain opportunistic pathogens. Here, we considered that endogenous opioids might function as such compounds, given that they are among the first signals to be released at multiple tissue sites during host stress. We tested the ability of various opioid compounds to enhance the virulence of Pseudomonas aeruginosa using pyocyanin production as a biological readout, and demonstrated enhanced virulence when P. aeruginosa was exposed to synthetic (U-50,488 and endogenous (dynorphin kappa-agonists. Using various mutants and reporter strains of P. aeruginosa, we identified involvement of key elements of the quorum sensing circuitry such as the global transcriptional regulator MvfR and the quorum sensing-related quinolone signaling molecules PQS, HHQ, and HQNO that respond to kappa-opioids. The in vivo significance of kappa-opioid signaling of P. aeruginosa was demonstrated in mice by showing that dynorphin is released from the intestinal mucosa following ischemia/reperfusion injury, activates quinolone signaling in P. aeruginosa, and enhances the virulence of P. aeruginosa against Lactobacillus spp. and Caenorhabditis elegans. Taken together, these data demonstrate that P. aeruginosa can intercept opioid compounds released during host stress and integrate them into core elements of quorum sensing circuitry leading to enhanced virulence.

  1. Standardized chemical synthesis of Pseudomonas aeruginosa pyocyanin

    Directory of Open Access Journals (Sweden)

    Rajkumar Cheluvappa

    2014-01-01

    As we have extracted pyocyanin both from P. aeruginosa cultures, and via chemical synthesis; we know the procedural and product-quality differences. We endorse the relative ease, safety, and convenience of using the chemical synthesis described here. Crucially, our “naturally endotoxin-free” pyocyanin can be extracted easily without using infectious bacteria.

  2. Copper uptake by Pseudomonas aeruginosa isolated from infected burn patients.

    Science.gov (United States)

    Abboud, Muayad M; Saeed, Humodi A; Tarawneh, Khaled A; Khleifat, Khaled M; Al Tarawneh, Amjad

    2009-09-01

    Pseudomonas aeruginosa was isolated from infected burn patients and characterized by standard biochemical tests. The in vitro copper uptake was compared between this isolated pathogenic strain and two non-pathogenic control strains of gram positive bacteria Bacillus thuringiensis strain Israelis as well as gram negative bacteria Enterobacter aerogenes. Maximum copper uptake of 470 ppm/g biomass was obtained by P. aeruginosa strain, while the control strains B. thuringiensis and Enterobacter aerogenes had copper uptake of 350 and 383 ppm/g biomass, respectively. However, the lowest copper uptake (60 ppm/g biomass) was observed with another control the saprophytic strain Pseudomonas (Shewanella) putrefaciens. A further investigation regarding the effect of copper toxicity on bacterial growth, gave an MIC score of 600 ppm for P. aeruginosa strain compared to 460 and 300 ppm for the two gram positive and gram negative control strains, respectively. In tandem with these in vitro findings, blood analysis on burn patients infected with P. aeruginosa has indicated a selective decrease of copper (hypocupremia) and ceruloplasmin plasma levels. The iron metabolism was also affected by this copper deprivation leading to a similar decrease in plasma levels of PCV, iron, total iron binding capacity, and transferrin. All these hematological changes were significantly different (P < 0.05) from the matched group of non-infected burn patients. The observed hypocupremia in infected burn patients was attributed to demanding scavenger ability by P. aeruginosa strain for the copper of plasma.

  3. Influence of Pseudomonas aeruginosa on exacerbation in patients with bronchiectasis

    Directory of Open Access Journals (Sweden)

    Kiran Chawla

    2015-01-01

    Full Text Available Background: A majority of the studies done on the western population have shown that Pseudomonas aeruginosa causes many severe infections in patients with bronchiectasis as compared to other pathogens. There is scarcity of similar data from the Asian population. Materials and Methods: A prospective study was undertaken to identify the various pathogens isolated from the respiratory samples of 117 patients with bronchiectasis from south India and to compare the clinicomicrobiological profile of infections caused by P. aeruginosa and other respiratory pathogens. Results: The respiratory pathogens were isolated from 63 (53.8% patients. P. aeruginosa was the most common isolate (46.0% followed by Klebsiella pneumoniae (14.3% and other pathogenic bacteria. Patients included in the P. aeruginosa group had a higher number of exacerbations (p: 0.008, greater number of hospital admissions (p: 0.007, a prolonged hospital stay (p: 0.03, and poor lung function, compared to the patients infected with the non-Pseudomonas group. Conclusion: It is necessary to investigate the etiology of respiratory tract infections among bronchiectasis patients followed by the prompt management of cases diagnosed with P. aeruginosa infections, so as to lower the morbidity and have a better prognosis.

  4. Electrical enhancement of biocide efficacy against Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Blenkinsopp, S A; Khoury, A E; Costerton, J W

    1992-01-01

    When applied within a low-strength electric field (+/- 12 V/cm) with a low current density (+/- 2.1 mA/cm2), several industrial biocides exhibited enhanced killing action against Pseudomonas aeruginosa biofilms grown on stainless steel studs. Biocide concentrations lower than those necessary to kill planktonic cells of P. aeruginosa (1, 5, and 10 ppm of the active ingredients of kathon, glutaraldehyde, and quaternary ammonium compound, respectively) were bactericidal within 24 h when applied within our electrified device. PMID:1482196

  5. Ciprofloxacin susceptibility of Pseudomonas aeruginosa isolates from keratitis

    DEFF Research Database (Denmark)

    Lomholt, JA; Kilian, Mogens

    2003-01-01

    AIM: To examine the ciprofloxacin susceptibility of 106 Pseudomonas aeruginosa eye isolates from the United Kingdom, Denmark, India, the United States, and Australia, and to determine the molecular mechanisms of resistance. METHODS: Ciprofloxacin susceptibility was tested by an agar dilution method...... isolates of P aeruginosa from European countries are fully susceptible to ciprofloxacin and the concentration of ciprofloxacin eye drops used for local treatment (3000 mg/l) exceeds MIC values for strains recorded as resistant. Mutations in more than one target gene were associated with higher MIC values....

  6. Staphylococcus aureus Protein A Mediates Interspecies Interactions at the Cell Surface of Pseudomonas aeruginosa.

    Science.gov (United States)

    Armbruster, Catherine R; Wolter, Daniel J; Mishra, Meenu; Hayden, Hillary S; Radey, Matthew C; Merrihew, Gennifer; MacCoss, Michael J; Burns, Jane; Wozniak, Daniel J; Parsek, Matthew R; Hoffman, Lucas R

    2016-05-24

    While considerable research has focused on the properties of individual bacteria, relatively little is known about how microbial interspecies interactions alter bacterial behaviors and pathogenesis. Staphylococcus aureus frequently coinfects with other pathogens in a range of different infectious diseases. For example, coinfection by S. aureus with Pseudomonas aeruginosa occurs commonly in people with cystic fibrosis and is associated with higher lung disease morbidity and mortality. S. aureus secretes numerous exoproducts that are known to interact with host tissues, influencing inflammatory responses. The abundantly secreted S. aureus staphylococcal protein A (SpA) binds a range of human glycoproteins, immunoglobulins, and other molecules, with diverse effects on the host, including inhibition of phagocytosis of S. aureus cells. However, the potential effects of SpA and other S. aureus exoproducts on coinfecting bacteria have not been explored. Here, we show that S. aureus-secreted products, including SpA, significantly alter two behaviors associated with persistent infection. We found that SpA inhibited biofilm formation by specific P. aeruginosa clinical isolates, and it also inhibited phagocytosis by neutrophils of all isolates tested. Our results indicate that these effects were mediated by binding to at least two P. aeruginosa cell surface structures-type IV pili and the exopolysaccharide Psl-that confer attachment to surfaces and to other bacterial cells. Thus, we found that the role of a well-studied S. aureus exoproduct, SpA, extends well beyond interactions with the host immune system. Secreted SpA alters multiple persistence-associated behaviors of another common microbial community member, likely influencing cocolonization and coinfection with other microbes. Bacteria rarely exist in isolation, whether on human tissues or in the environment, and they frequently coinfect with other microbes. However, relatively little is known about how

  7. Antibiotic strategies for eradicating Pseudomonas aeruginosa in people with cystic fibrosis.

    Science.gov (United States)

    Langton Hewer, Simon C; Smyth, Alan R

    2017-04-25

    Respiratory tract infection with Pseudomonas aeruginosa occurs in most people with cystic fibrosis. Once chronic infection is established, Pseudomonas aeruginosa is virtually impossible to eradicate and is associated with increased mortality and morbidity. Early infection may be easier to eradicate.This is an update of a Cochrane review first published in 2003, and previously updated in 2006, 2009 and 2014. To determine whether antibiotic treatment of early Pseudomonas aeruginosa infection in children and adults with cystic fibrosis eradicates the organism, delays the onset of chronic infection, and results in clinical improvement. To evaluate whether there is evidence that a particular antibiotic strategy is superior to or more cost-effective than other strategies and to compare the adverse effects of different antibiotic strategies (including respiratory infection with other micro-organisms). We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Most recent search: 10 October 2016. We included randomised controlled trials of people with cystic fibrosis, in whom Pseudomonas aeruginosa had recently been isolated from respiratory secretions. We compared combinations of inhaled, oral or intravenous antibiotics with placebo, usual treatment or other combinations of inhaled, oral or intravenous antibiotics. We excluded non-randomised trials, cross-over trials, and those utilising historical controls. Both authors independently selected trials, assessed risk of bias and extracted data. The search identified 60 trials; seven trials (744 participants) with a duration between 28 days and 27 months were eligible for inclusion. Three of the trials are over 10 years old and their results may be less applicable today given the changes in standard treatment. Some of the trials had low

  8. Relationship of Virulence Factors and Clinical Features in Keratitis Caused by Pseudomonas aeruginosa.

    Science.gov (United States)

    Oka, Naoko; Suzuki, Takashi; Ishikawa, Eri; Yamaguchi, Satoshi; Hayashi, Naoki; Gotoh, Naomasa; Ohashi, Yuichi

    2015-10-01

    To examine bacterial virulence factors in Pseudomonas aeruginosa isolates from contact lens (CL) wearers and non-CL wearers with P. aeruginosa keratitis, and to investigate relationships between virulence factors and clinical features of keratitis. The study involved 25 subjects including 18 CL and 7 non-CL-related P. aeruginosa keratitis patients. Slit-lamp photographs of all subjects were captured, and the focus occupancy ratio (FOR) was defined as the total focus area/entire cornea area, using image processing software. Twenty-five clinical P. aeruginosa isolates from keratitis were assessed for protease production, elastase production, biofilm formation, bacterial swimming and swarming motility, cell surface hydrophobicity, and genes encoding the type III secretion system (TTSS) effectors (ExoU and ExoS). Ring abscess was found in 9 of 18 CL-related P. aeruginosa keratitis cases (CL[+] ring[+] group) but not in another 9 cases (CL[+] ring[-] group). Expression or prevalence of virulence factors in P. aeruginosa isolates from the CL(+) ring(+) group, CL(+) ring(-) group, and CL(-) group were compared. The FOR for CL(+) ring(+) or CL(-) was higher than for CL(+) ring(-) (P keratitis.

  9. Chemical Inhibition of Kynureninase Reduces Pseudomonas aeruginosa Quorum Sensing and Virulence Factor Expression.

    Science.gov (United States)

    Kasper, Stephen H; Bonocora, Richard P; Wade, Joseph T; Musah, Rabi Ann; Cady, Nathaniel C

    2016-04-15

    The opportunistic pathogen Pseudomonas aeruginosa utilizes multiple quorum sensing (QS) pathways to coordinate an arsenal of virulence factors. We previously identified several cysteine-based compounds inspired by natural products from the plant Petiveria alliacea which are capable of antagonizing multiple QS circuits as well as reducing P. aeruginosa biofilm formation. To understand the global effects of such compounds on virulence factor production and elucidate their mechanism of action, RNA-seq transcriptomic analysis was performed on P. aeruginosa PAO1 exposed to S-phenyl-l-cysteine sulfoxide, the most potent inhibitor from the prior study. Exposure to this inhibitor down-regulated expression of several QS-regulated virulence operons (e.g., phenazine biosynthesis, type VI secretion systems). Interestingly, many genes that were differentially regulated pertain to the related metabolic pathways that yield precursors of pyochelin, tricarboxylic acid cycle intermediates, phenazines, and Pseudomonas quinolone signal (PQS). Activation of the MexT-regulon was also indicated, including the multidrug efflux pump encoded by mexEF-oprN, which has previously been shown to inhibit QS and pathogenicity. Deeper investigation of the metabolites involved in these systems revealed that S-phenyl-l-cysteine sulfoxide has structural similarity to kynurenine, a precursor of anthranilate, which is critical for P. aeruginosa virulence. By supplementing exogenous anthranilate, the QS-inhibitory effect was reversed. Finally, it was shown that S-phenyl-l-cysteine sulfoxide competitively inhibits P. aeruginosa kynureninase (KynU) activity in vitro and reduces PQS production in vivo. The kynurenine pathway has been implicated in P. aeruginosa QS and virulence factor expression; however, this is the first study to show that targeted inhibition of KynU affects P. aeruginosa gene expression and QS, suggesting a potential antivirulence strategy.

  10. Candida albicans Inhibits Pseudomonas aeruginosa Virulence through Suppression of Pyochelin and Pyoverdine Biosynthesis

    Science.gov (United States)

    Lopez-Medina, Eduardo; Fan, Di; Coughlin, Laura A.; Ho, Evi X.; Lamont, Iain L.; Reimmann, Cornelia; Hooper, Lora V.; Koh, Andrew Y.

    2015-01-01

    Bacterial-fungal interactions have important physiologic and medical ramifications, but the mechanisms of these interactions are poorly understood. The gut is host to trillions of microorganisms, and bacterial-fungal interactions are likely to be important. Using a neutropenic mouse model of microbial gastrointestinal colonization and dissemination, we show that the fungus Candida albicans inhibits the virulence of the bacterium Pseudomonas aeruginosa by inhibiting P. aeruginosa pyochelin and pyoverdine gene expression, which plays a critical role in iron acquisition and virulence. Accordingly, deletion of both P. aeruginosa pyochelin and pyoverdine genes attenuates P. aeruginosa virulence. Heat-killed C. albicans has no effect on P. aeruginosa, whereas C. albicans secreted proteins directly suppress P. aeruginosa pyoverdine and pyochelin expression and inhibit P. aeruginosa virulence in mice. Interestingly, suppression or deletion of pyochelin and pyoverdine genes has no effect on P. aeruginosa’s ability to colonize the GI tract but does decrease P. aeruginosa’s cytotoxic effect on cultured colonocytes. Finally, oral iron supplementation restores P. aeruginosa virulence in P. aeruginosa and C. albicans colonized mice. Together, our findings provide insight into how a bacterial-fungal interaction can modulate bacterial virulence in the intestine. Previously described bacterial-fungal antagonistic interactions have focused on growth inhibition or colonization inhibition/modulation, yet here we describe a novel observation of fungal-inhibition of bacterial effectors critical for virulence but not important for colonization. These findings validate the use of a mammalian model system to explore the complexities of polymicrobial, polykingdom infections in order to identify new therapeutic targets for preventing microbial disease. PMID:26313907

  11. The Pseudomonas aeruginosa opportunistic pathogen and human infections.

    Science.gov (United States)

    de Bentzmann, Sophie; Plésiat, Patrick

    2011-07-01

    Pseudomonas aeruginosa, a Gram-negative environmental species and an opportunistic microorganism, establishes itself in vulnerable patients, such as those with cystic fibrosis or hospitalized in intensive care units. It has become a major cause of nosocomial infections worldwide (about 10% of all such infections in most European Union hospitals) and a serious threat to Public Health. The overuse and misuse of antibiotics have also led to the selection of resistant strains against which very few therapeutic options exist. How an environmental species can cause human infections remains a key question that still needs elucidation despite the incredibly high progress that has been made in the P. aeruginosa biology over the past decades. The workshop belonging to Current trends in Biomedicine series, which was held under the sponsorship of the Universidad International de Andalucia between the 8th and the 10th November 2010 brought in the most recent advances in the environmental life of P. aeruginosa, the human P. aeruginosa infections, the new animal models to study Pseudomonas infections, the new genetic aspects including metabolomics, genomics and bioinformatics and the community lifestyle named biofilm that accounts for P. aeruginosa persistence in humans. This workshop organized by Soeren Molin (Danemark), Juan-Luis Ramos (Spain) and Sophie de Bentzmann (France) gathered 46 researchers coming from 11 European and American countries in a small format and was hosted in the 'Sede Antonio Machado' in Baeza. It was organized in seven sessions covering animal models for P. aeruginosa pathogenesis, resistance to drugs, regulatory potency including small RNA, two component systems, extracytoplasmic function sigma factors and trancriptional regulators, new therapies emerging from dissection of molecular mechanisms, and evolutionary mechanisms of P. aeruginosa strains in patients. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  12. Ferric Uptake Regulator Fur Is Conditionally Essential in Pseudomonas aeruginosa.

    Science.gov (United States)

    Pasqua, Martina; Visaggio, Daniela; Lo Sciuto, Alessandra; Genah, Shirley; Banin, Ehud; Visca, Paolo; Imperi, Francesco

    2017-11-15

    In Pseudomonas aeruginosa, the ferric uptake regulator (Fur) protein controls both metabolism and virulence in response to iron availability. Differently from other bacteria, attempts to obtain fur deletion mutants of P. aeruginosa failed, leading to the assumption that Fur is an essential protein in this bacterium. By investigating a P. aeruginosa conditional fur mutant, we demonstrate that Fur is not essential for P. aeruginosa growth in liquid media, biofilm formation, and pathogenicity in an insect model of infection. Conversely, Fur is essential for growth on solid media since Fur-depleted cells are severely impaired in colony formation. Transposon-mediated random mutagenesis experiments identified pyochelin siderophore biosynthesis as a major cause of the colony growth defect of the conditional fur mutant, and deletion mutagenesis confirmed this evidence. Impaired colony growth of pyochelin-proficient Fur-depleted cells does not depend on oxidative stress, since Fur-depleted cells do not accumulate higher levels of reactive oxygen species (ROS) and are not rescued by antioxidant agents or overexpression of ROS-detoxifying enzymes. Ectopic expression of pch genes revealed that pyochelin production has no inhibitory effects on a fur deletion mutant of Pseudomonas syringae pv. tabaci, suggesting that the toxicity of the pch locus in Fur-depleted cells involves a P. aeruginosa-specific pathway(s).IMPORTANCE Members of the ferric uptake regulator (Fur) protein family are bacterial transcriptional repressors that control iron uptake and storage in response to iron availability, thereby playing a crucial role in the maintenance of iron homeostasis. While fur null mutants of many bacteria have been obtained, Fur appears to be essential in Pseudomonas aeruginosa for still unknown reasons. We obtained Fur-depleted P. aeruginosa cells by conditional mutagenesis and showed that Fur is dispensable for planktonic growth, while it is required for colony formation. This is

  13. Effect of dietary monosaccharides on Pseudomonas aeruginosa virulence.

    Science.gov (United States)

    Nelson, Ryan K; Poroyko, Valeriy; Morowitz, Michael J; Liu, Don; Alverdy, John C

    2013-02-01

    Pseudomonas aeruginosa is an opportunistic, gram-negative pathogen associated with many hospital-acquired infections and disease states. In particular, P. aeruginosa has been identified as a crucial factor in the pathogenesis of neonatal necrotizing enterocolitis (NEC). This condition presents more frequently in infants fed a formula-based diet, which may be a result of the specific monosaccharide content of this diet. We hypothesized that P. aeruginosa would express virulence genes differentially when exposed to monosaccharides present in formula versus those in human milk. Using the results of a metabolomics study on infant diets and their resulting fecal samples, we identified several monosaccharides that distinguished milk from formula diets. Of these compounds, four were found to be metabolized by P. aeruginosa. We subsequently grew P. aeruginosa in tryptic soy broth (TSB) supplemented with these four monosaccharides and used quantitative reverse transcriptase-polymerase chain reaction to measure the expression of 59 major P. aeruginosa virulence genes. The results were standardized to an external control of P. aeruginosa grown in TSB alone. P. aeruginosa did not respond differentially to the monosaccharides after 6 h of growth. However, after 24 h, the organism grown in arabinose (present in formula), xylose (present in human milk), and galactose (present in both formula and feces from milk-fed infants) displayed a significant increase in the expression of virulence genes in all categories. In contrast, P. aeruginosa grown in mannose (present in the feces of milk-fed infants) displayed a significant decrease in virulence gene expression. These results demonstrate the importance of nutrient content on the relative expression of virulence genes in pathogens that colonize commonly the gut of infants. Understanding the effect of current dietary formulas on virulence gene expression in various gut-colonizing pathogens may present a new approach to elucidating the

  14. A dynamic and intricate regulatory network determines Pseudomonas aeruginosa virulence

    Science.gov (United States)

    Balasubramanian, Deepak; Schneper, Lisa; Kumari, Hansi; Mathee, Kalai

    2013-01-01

    Pseudomonas aeruginosa is a metabolically versatile bacterium that is found in a wide range of biotic and abiotic habitats. It is a major human opportunistic pathogen causing numerous acute and chronic infections. The critical traits contributing to the pathogenic potential of P. aeruginosa are the production of a myriad of virulence factors, formation of biofilms and antibiotic resistance. Expression of these traits is under stringent regulation, and it responds to largely unidentified environmental signals. This review is focused on providing a global picture of virulence gene regulation in P. aeruginosa. In addition to key regulatory pathways that control the transition from acute to chronic infection phenotypes, some regulators have been identified that modulate multiple virulence mechanisms. Despite of a propensity for chaotic behaviour, no chaotic motifs were readily observed in the P. aeruginosa virulence regulatory network. Having a ‘birds-eye’ view of the regulatory cascades provides the forum opportunities to pose questions, formulate hypotheses and evaluate theories in elucidating P. aeruginosa pathogenesis. Understanding the mechanisms involved in making P. aeruginosa a successful pathogen is essential in helping devise control strategies. PMID:23143271

  15. Mechanisms of phagocytosis and host clearance of Pseudomonas aeruginosa

    Science.gov (United States)

    Lovewell, Rustin R.; Patankar, Yash R.

    2014-01-01

    Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for a high incidence of acute and chronic pulmonary infection. These infections are particularly prevalent in patients with chronic obstructive pulmonary disease and cystic fibrosis: much of the morbidity and pathophysiology associated with these diseases is due to a hypersusceptibility to bacterial infection. Innate immunity, primarily through inflammatory cytokine production, cellular recruitment, and phagocytic clearance by neutrophils and macrophages, is the key to endogenous control of P. aeruginosa infection. In this review, we highlight recent advances toward understanding the innate immune response to P. aeruginosa, with a focus on the role of phagocytes in control of P. aeruginosa infection. Specifically, we summarize the cellular and molecular mechanisms of phagocytic recognition and uptake of P. aeruginosa, and how current animal models of P. aeruginosa infection reflect clinical observations in the context of phagocytic clearance of the bacteria. Several notable phenotypic changes to the bacteria are consistently observed during chronic pulmonary infections, including changes to mucoidy and flagellar motility, that likely enable or reflect their ability to persist. These traits are likewise examined in the context of how the bacteria avoid phagocytic clearance, inflammation, and sterilizing immunity. PMID:24464809

  16. Probenecid reduces infection and inflammation in acute Pseudomonas aeruginosa pneumonia.

    Science.gov (United States)

    Wonnenberg, Bodo; Tschernig, Thomas; Voss, Meike; Bischoff, Markus; Meier, Carola; Schirmer, Stephan H; Langer, Frank; Bals, Robert; Beisswenger, Christoph

    2014-07-01

    The activation of inflammasome signaling mediates pathology of acute Pseudomonas aeruginosa pneumonia. This suggests that the inflammasome might represent a target to limit the pathological consequences of acute P. aeruginosa lung infection. Pannexin-1 (Px1) channels mediate the activation of caspase-1 and release of IL-1β induced by P2X7 receptor activation. The approved drug probenecid is an inhibitor of Px1 and ATP release. In this study, we demonstrate that probenecid reduces infection and inflammation in acute P. aeruginosa pneumonia. Treatment of mice prior to infection with P. aeruginosa resulted in an enhanced clearance of P. aeruginosa and reduced levels of inflammatory mediators, such as IL-1β. In addition, probenecid inhibited the release of inflammatory mediators in murine alveolar macrophages and human U937 cell-derived macrophages upon bacterial infection but not in human bronchial epithelial cells. Thus, Px1 blockade via probenecid treatment may be a therapeutic option in P. aeruginosa pneumonia by improving bacterial clearance and reducing negative consequences of inflammation. Copyright © 2014 Elsevier GmbH. All rights reserved.

  17. PSEUDOMONAS AERUGINOSA IN CHRONIC SUPPURATIVE OTITIS MEDIA- A DRUGSENSITIVITY STUDY

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    Anoop M

    2017-05-01

    Full Text Available BACKGROUND Chronic suppurative otitis media is one among the commonest ENT disease seen in day-to-day practice. It is seen mainly among low socioeconomic class. MATERIALS AND METHODS The present study was conducted in the Department of ENT, Shadan Institute of Medical Sciences. Fifty patients with CSOM of all age groups and both sexes attending the Outpatient Department of ENT were selected randomly for the study. RESULTS From our study, we found mainly children of age group 10-11 years commonly affected. They belong to poor socioeconomic background. Pseudomonas aeruginosa is the most common organism isolated in the present study. Ciprofloxacin was found to be the most sensitive antibiotic to Pseudomonas aeruginosa. CONCLUSION We noticed that drug resistance is on the rise due to misuse of antibiotics, over-the-counter treatment, inadequate period of therapy and less awareness among public regarding drug resistance. Constant monitoring of antibiotic sensitivity is needed to prevent drug resistance in CSOM.

  18. Neonatal Orbital Abscess Secondary to Pseudomonas Aeruginosa Conjunctivitis.

    Science.gov (United States)

    Yazici, Bulent; Orucov, Nesimi; Ibrahimzade, Gunay

    Pseudomonas aeruginosa conjunctivitis, although rare in healthy infants, may cause serious ocular and systemic complications. A 30-day-old, otherwise healthy male infant was referred with the diagnosis of right orbital abscess. The patient had been diagnosed as having Pseudomonas conjunctivitis 9 days previously at the referring center. Despite antibiotic treatment, his ocular findings had worsened and marked proptosis had developed. Other examination findings were ptosis, restriction of eye movements, periorbital erythema, and chemosis. Radiologic studies showed a large, homogenous mass with a thick capsule in the lateral retrobulbar orbit. The abscess was drained through a lateral orbitotomy. A culture of the abscess yielded P. aeruginosa. After surgery, the ocular findings improved rapidly without any complication. No other focus of infection or immune system abnormality was found. The patient did not experience any other significant disease during a follow up of 23 months.

  19. Genome-wide screen of Pseudomonas aeruginosa In Saccharomyces cerevisiae identifies new virulence factors

    Directory of Open Access Journals (Sweden)

    Rafat eZrieq

    2015-11-01

    Full Text Available Pseudomonas aeruginosa is a human opportunistic pathogen that causes mortality in cystic fibrosis and immunocompromised patients. While many virulence factors of this pathogen have already been identified, several remain to be discovered. In this respect we set an unprecedented genome-wide screen of a P. aeruginosa expression library based on a yeast growth phenotype. 51 candidates were selected in a three-round screening process. The robustness of the screen was validated by the selection of three well known secreted proteins including one demonstrated virulence factor, the protease LepA. Further in silico sorting of the 51 candidates highlighted three potential new Pseudomonas effector candidates (Pec. By testing the cytotoxicity of wild type P. aeruginosa vs pec mutants towards macrophages and the virulence in the Caenorhabditis elegans model, we demonstrated that the three selected Pecs are novel virulence factors of P. aeruginosa. Additional cellular localization experiments in the host revealed specific localization for Pec1 and Pec2 that could inform about their respective functions.

  20. [Phlegmonous gastritis. Report of a case induced by Pseudomonas aeruginosa].

    Science.gov (United States)

    Ramos Jiménez, F A; Arocena Cedrón, M G; Goikoetxea Artola, J M; Lázaro Aramburu, S; Múgica Barreiros, P

    1992-06-01

    The authors present a case of phlegmonous gastritis in a 65 year old patient. The diagnosis was made in the operating room and the treatment was conservative; no gastric resection was done. This clinical entity is interesting because it is a least frequent pathology, the pathogenic bacteria which was the cause (Pseudomona aeruginosa) has at this time not been reported in the literature, including the favorable outcome of the patient without gastric resection.

  1. Cloning and expression of Pseudomonas aeruginosa flagellin in Escherichia coli.

    OpenAIRE

    Kelly-Wintenberg, K; Montie, T. C.

    1989-01-01

    The flagellin gene was isolated from a Pseudomonas aeruginosa PAO1 genomic bank by conjugation into a PA103 Fla- strain. Flagellin DNA was transferred from motile recipient PA103 Fla+ cells by transformation into Escherichia coli. We show that transformed E. coli expresses flagellin protein. Export of flagellin to the E. coli cell surface was suggested by positive colony blots of unlysed cells and by isolation of flagellin protein from E. coli supernatants.

  2. Antimicrobial effect of probiotic Lactobacillus spp. on Pseudomonas aeruginosa

    OpenAIRE

    Maysaa Kadhim Al-Malkey; Munira Ch. Ismeeal; Fahema Jabbar Abo Al-Hur; Sinaa W. Mohammed; Hanan J. Nayyef

    2017-01-01

    Objectives Study the antimicrobial effect of probiotics produced from Lactobacillus rhamnosus GG and Lactobacillus acidophilus on Pseudomonas aeruginosa isolated from burn and wound infection and their ability of protease production. Methods Swab samples were collected from 70 patients admitted at Burns Center/Al-Yarmouk Teaching Hospital. Primary bacterial identification cultured on differential selective media and biochemical tests were done. The Vitek2 compact system (Biomerieux, France...

  3. Extracellular DNA Shields against Aminoglycosides in Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Nilsson, Martin; Jensen, Peter Østrup

    2013-01-01

    Within recent years, it has been established that extracellular DNA is a key constituent of the matrix of microbial biofilms. In addition, it has recently been demonstrated that DNA binds positively charged antimicrobials such as aminoglycosides and antimicrobial peptides. In the present study, w...... that the aminoglycoside tolerance mediated by the presence of extracellular DNA is not caused by activation of the pmr genes in our P. aeruginosa biofilms but rather by a protective shield effect of the extracellular DNA....... provide evidence that extracellular DNA shields against aminoglycosides in Pseudomonas aeruginosa biofilms. We show that exogenously supplemented DNA integrates into P. aeruginosa biofilms and increases their tolerance toward aminoglycosides. We provide evidence that biofilms formed by a DNA release...

  4. Hyperbaric oxygen sensitizes anoxic Pseudomonas aeruginosa biofilm to ciprofloxacin

    DEFF Research Database (Denmark)

    Kolpen, Mette; Lerche, Christian J; Kragh, Kasper Nørskov

    2017-01-01

    Chronic Pseudomonas aeruginosa lung infection is characterized by the presence of endobronchial antibiotic-tolerant biofilm subject to strong oxygen (O2) depletion due to the activity of surrounding polymorphonuclear leukocytes. The exact mechanisms affecting the antibiotic susceptibility...... metabolism activity and the endogenous formation of reactive O2 radicals (ROS). In this study we aimed to apply hyperbaric oxygen treatment (HBOT) in order to sensitize anoxic P. aeruginosa agarose-biofilms established to mimic situations with intense O2 consumption by the host response in the cystic...... that oxygenation by HBOT improves the bactericidal activity of ciprofloxacin on P. aeruginosa biofilm and suggest that bacterial biofilms is sensitized to antibiotics by supplying hyperbaric O2....

  5. Pseudomonas aeruginosa PA14 pathogenesis in Caenorhabditis elegans.

    Science.gov (United States)

    Kirienko, Natalia V; Cezairliyan, Brent O; Ausubel, Frederick M; Powell, Jennifer R

    2014-01-01

    The nematode Caenorhabditis elegans is a simple model host for studying the interaction between bacterial pathogens such as Pseudomonas aeruginosa and the metazoan innate immune system. Powerful genetic and molecular tools in both C. elegans and P. aeruginosa facilitate the identification and analysis of bacterial virulence factors as well as host defense factors. Here we describe three different assays that use the C. elegans-P. aeruginosa strain PA14 host-pathogen system. Fast Killing is a toxin-mediated death that depends on a diffusible toxin produced by PA14 but not on live bacteria. Slow Killing is due to an active infection in which bacteria colonize the C. elegans intestinal lumen. Liquid Killing is designed for high-throughput screening of chemical libraries for anti-infective compounds. Each assay has unique features and, interestingly, the PA14 virulence factors involved in killing are different in each assay.

  6. Pseudomonas aeruginosa Biofilm, a Programmed Bacterial Life for Fitness.

    Science.gov (United States)

    Lee, Keehoon; Yoon, Sang Sun

    2017-06-28

    A biofilm is a community of microbes that typically inhabit on surfaces and are encased in an extracellular matrix. Biofilms display very dissimilar characteristics to their planktonic counterparts. Biofilms are ubiquitous in the environment and influence our lives tremendously in both positive and negative ways. Pseudomonas aeruginosa is a bacterium known to produce robust biofilms. P. aeruginosa biofilms cause severe problems in immunocompromised patients, including those with cystic fibrosis or wound infection. Moreover, the unique biofilm properties further complicate the eradication of the biofilm infection, leading to the development of chronic infections. In this review, we discuss the history of biofilm research and general characteristics of bacterial biofilms. Then, distinct features pertaining to each stage of P. aeruginosa biofilm development are highlighted. Furthermore, infections caused by biofilms on their own or in association with other bacterial species (i.e., multispecies biofilms) are discussed in detail.

  7. Outbreak of Pseudomonas aeruginosa bacteraemia in a haematology department

    DEFF Research Database (Denmark)

    Rasmussen, Benjamin Schnack; Christensen, Nikolas; Sørensen, Jan

    2015-01-01

    INTRODUCTION: Infection by Pseudomonas aeruginosa represents a major cause of morbidity and mortality among immunocompromised patients. In Denmark, an increase in P. aeruginosa isolates from blood cultures from a haematology department prompted a hygienic audit in 2007. METHODS: Blood cultures...... the outbreak and 12 months later. The audits were conducted by the method of direct observation. RESULTS: Several PFGE types were involved with no clear association to isolates from environmental samples. The audit revealed poor hygiene related to the handling of central venous catheters. After optimising...... catheter hygiene, the number of P. aeruginosa bacteraemia cases fell significantly. CONCLUSION: Since no clear association between patient and environmental genotype was established, it was suspected that central venous catheters were the main portal of entry. This was further supported by a simultaneous...

  8. Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation.

    Science.gov (United States)

    Laverty, Garry; Gorman, Sean P; Gilmore, Brendan F

    2014-07-18

    Pseudomonas aeruginosa and Escherichia coli are the most prevalent Gram-negative biofilm forming medical device associated pathogens, particularly with respect to catheter associated urinary tract infections. In a similar manner to Gram-positive bacteria, Gram-negative biofilm formation is fundamentally determined by a series of steps outlined more fully in this review, namely adhesion, cellular aggregation, and the production of an extracellular polymeric matrix. More specifically this review will explore the biosynthesis and role of pili and flagella in Gram-negative adhesion and accumulation on surfaces in Pseudomonas aeruginosa and Escherichia coli. The process of biofilm maturation is compared and contrasted in both species, namely the production of the exopolysaccharides via the polysaccharide synthesis locus (Psl), pellicle Formation (Pel) and alginic acid synthesis in Pseudomonas aeruginosa, and UDP-4-amino-4-deoxy-l-arabinose and colonic acid synthesis in Escherichia coli. An emphasis is placed on the importance of the LuxR homologue sdiA; the luxS/autoinducer-II; an autoinducer-III/epinephrine/norepinephrine and indole mediated Quorum sensing systems in enabling Gram-negative bacteria to adapt to their environments. The majority of Gram-negative biofilms consist of polysaccharides of a simple sugar structure (either homo- or heteropolysaccharides) that provide an optimum environment for the survival and maturation of bacteria, allowing them to display increased resistance to antibiotics and predation.

  9. Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Garry Laverty

    2014-07-01

    Full Text Available Pseudomonas aeruginosa and Escherichia coli are the most prevalent Gram-negative biofilm forming medical device associated pathogens, particularly with respect to catheter associated urinary tract infections. In a similar manner to Gram-positive bacteria, Gram-negative biofilm formation is fundamentally determined by a series of steps outlined more fully in this review, namely adhesion, cellular aggregation, and the production of an extracellular polymeric matrix. More specifically this review will explore the biosynthesis and role of pili and flagella in Gram-negative adhesion and accumulation on surfaces in Pseudomonas aeruginosa and Escherichia coli. The process of biofilm maturation is compared and contrasted in both species, namely the production of the exopolysaccharides via the polysaccharide synthesis locus (Psl, pellicle Formation (Pel and alginic acid synthesis in Pseudomonas aeruginosa, and UDP-4-amino-4-deoxy-l-arabinose and colonic acid synthesis in Escherichia coli. An emphasis is placed on the importance of the LuxR homologue sdiA; the luxS/autoinducer-II; an autoinducer-III/epinephrine/norepinephrine and indole mediated Quorum sensing systems in enabling Gram-negative bacteria to adapt to their environments. The majority of Gram-negative biofilms consist of polysaccharides of a simple sugar structure (either homo- or heteropolysaccharides that provide an optimum environment for the survival and maturation of bacteria, allowing them to display increased resistance to antibiotics and predation.

  10. Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation

    Science.gov (United States)

    Laverty, Garry; Gorman, Sean P.; Gilmore, Brendan F.

    2014-01-01

    Pseudomonas aeruginosa and Escherichia coli are the most prevalent Gram-negative biofilm forming medical device associated pathogens, particularly with respect to catheter associated urinary tract infections. In a similar manner to Gram-positive bacteria, Gram-negative biofilm formation is fundamentally determined by a series of steps outlined more fully in this review, namely adhesion, cellular aggregation, and the production of an extracellular polymeric matrix. More specifically this review will explore the biosynthesis and role of pili and flagella in Gram-negative adhesion and accumulation on surfaces in Pseudomonas aeruginosa and Escherichia coli. The process of biofilm maturation is compared and contrasted in both species, namely the production of the exopolysaccharides via the polysaccharide synthesis locus (Psl), pellicle Formation (Pel) and alginic acid synthesis in Pseudomonas aeruginosa, and UDP-4-amino-4-deoxy-l-arabinose and colonic acid synthesis in Escherichia coli. An emphasis is placed on the importance of the LuxR homologue sdiA; the luxS/autoinducer-II; an autoinducer-III/epinephrine/norepinephrine and indole mediated Quorum sensing systems in enabling Gram-negative bacteria to adapt to their environments. The majority of Gram-negative biofilms consist of polysaccharides of a simple sugar structure (either homo- or heteropolysaccharides) that provide an optimum environment for the survival and maturation of bacteria, allowing them to display increased resistance to antibiotics and predation. PMID:25438014

  11. Experimental Pseudomonas aeruginosa mediated rhino sinusitis in mink.

    Science.gov (United States)

    Kirkeby, S; Hammer, A S; Høiby, N; Salomonsen, C M

    2017-05-01

    The nasal and sinus cavities in children may serve as reservoirs for microorganisms that cause recurrent and chronic lung infections. This study evaluates whether the mink can be used as an animal model for studying Pseudomonas aeruginosa mediated rhino-sinusitis since there is no suitable traditional animal model for this disease. Nasal tissue samples from infected and control mink were fixed in formalin, demineralized, and embedded in paraffin. A histological examination of sections from the infected animals revealed disintegration of the respiratory epithelium lining the nasal turbinates and swelling and edema of the submucosa. The expression of mucins and sialylated glycans was examined using immunohistochemistry. MUC1, MUC2 and MUC5AC were upregulated in the inoculated animals as a much stronger staining was present in the respiratory epithelium in the infected animals compared to the controls. The goblet cells in the nasal epithelium from the infected mink showed high affinity to the Maackia amurensis lectin and anti-asialo GM1 indicating a high concentration of α2-3 sialic acid respectively βGalNAc1-4Galβ containing glycans in these mucin producing cells. The nasal cavity in the infected mink shows features of carbohydrate expression comparable to what has been described in the respiratory system after Pseudomonas aeruginosa infection in humans. It is suggested that the mink is suitable for studying Pseudomonas aeruginosa mediated rhino-sinusitis. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  12. Inactivation of Pseudomonas aeruginosa by Chitosan Coated Iron Oxide Nanoparticles.

    Science.gov (United States)

    Mukherjee, Munmun; De, Sirshendu

    2016-01-01

    Pseudomonas aeruginosa is one of the potent opportunistic pathogens associated with respiratory and urinary tract infection. The bacterium owes its pathogenicity due to the intrinsic resistance to antibiotics and disinfectants. The present study is focused on the synthesis of antibacterial chitosan coated iron oxide nanoparticles for rapid inactivation of Pseudomonas aeruginosa. We have discussed the relevant patents on synthesis and antibacterial potential of metallic nanoparticles and chitosan. Chitosan coated iron oxide nanoparticles were synthesized by coprecipitation method at room temperature using non-toxic chitosan and iron salts in alkali media. The particles were characterized and evaluated for antibacterial property against Pseudomonas aeruginosa. The average size of the particles was measured as 52 nm. The surface area of the coated particles was as high as 90 ±5 m2/g. FTIR spectra confirmed the coating of chitosan on nanoparticles. The coated particles showed excellent antibacterial activity against the bacteria. The minimum inhibitory concentration of the coated particles was 105)µg mol-1. The morphological alteration and cytoplasmic leakage of bacteria were confirmed by SEM image and release of intracellular constituents, respectively. Higher 260 nm absorbance value confirmed stronger antibacterial activity of the coated nanoparticles as compared to pure chitosan and bare iron oxide nanoparticles. The study indicated that chitosan coated iron oxide nanoparticles have superior antibacterial property as compared to pure chitosan and iron oxide nanoparticles.

  13. Reduction of PCN biosynthesis by NO in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Lei Gao

    2016-08-01

    Full Text Available Pyocyanin (PCN, a virulence factor synthesized by Pseudomonas aeruginosa, plays an important role during clinical infections. There is no study of the effect of nitric oxide (NO on PCN biosynthesis. Here, the effect of NO on PCN levels in Pseudomonas aeruginosa strain PAO1, a common reference strain, was tested. The results showed that the NO donor sodium nitroprusside (SNP can significantly reduce PCN levels (82.5% reduction at 60 μM SNP. Furthermore, the effect of endogenous NO on PCN was tested by constructing PAO1 nor (NO reductase gene knockout mutants. Compared to the wild-type strain, the Δnor strain had a lower PCN (86% reduction in Δnor. To examine whether the results were universal with other P. aeruginosa strains, we collected 4 clinical strains from a hospital, tested their PCN levels after SNP treatment, and obtained similar results, i.e., PCN biosynthesis was inhibited by NO. These results suggest that NO treatment may be a new strategy to inhibit PCN biosynthesis and could provide novel insights into eliminating P. aeruginosa virulence as a clinical goal.

  14. Molecular detection of an atypical, highly resistant, clonal Pseudomonas aeruginosa isolate in cystic fibrosis patients.

    LENUS (Irish Health Repository)

    Keating, Deirdre

    2013-03-01

    The identification of Pseudomonas aeruginosa (P. aeruginosa) isolates in sputum from cystic fibrosis (CF) patients can be challenging due to the multitude of phenotypic changes isolates undergo during adaptation to the microenvironment of the CF lung.

  15. Colistin-Tobramycin Combinations Are Superior to Monotherapy Concerning the Killing of Biofilm Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Herrmann, G.; Yang, Liang; Wu, H.

    2010-01-01

    Background. Antibiotic combination therapy might be more efficient than single antibiotics to combat Pseudomonas aeruginosa biofilms in the airways of patients with cystic fibrosis. We tested the ability of colistin sulphatetobramycin combinations and single antibiotics to kill P. aeruginosa biof...

  16. Activation of pulmonary and lymph node dendritic cells during chronic Pseudomonas aeruginosa lung infection in mice

    DEFF Research Database (Denmark)

    Damlund, Dina S. M.; Christophersen, Lars; Jensen, Peter Østrup

    2016-01-01

    The majority of cystic fibrosis (CF) patients acquire chronic Pseudomonas aeruginosa lung infection, resulting in increased mortality and morbidity. The chronic P. aeruginosa lung infection is characterized by bacteria growing in biofilm surrounded by polymorphonuclear neutrophils (PMNs). However...

  17. Initial Pseudomonas aeruginosa infection in patients with cystic fibrosis: characteristics of eradicated and persistent isolates

    DEFF Research Database (Denmark)

    Tramper-Stranders, G. A.; van der Ent, C. K.; Molin, Søren

    2012-01-01

    Clin Microbiol Infect 2012; 18: 567574 Abstract Despite intensive eradication therapy, some CF patients with early Pseudomonas aeruginosa infection rapidly develop a chronic infection. To elucidate factors associated with this persistence, bacterial characteristics of early P. aeruginosa isolates...

  18. Pseudomonas aeruginosa exotoxin A-induced hepatotoxicity in dynamics: an animal model in white mice

    National Research Council Canada - National Science Library

    Morrison A.V; Popovich V.I; Morrison V.V

    2015-01-01

    .... Material and Methods. The experiments were carried out on white mice in dynamics development of pseudomonas aeruginosa caused by intraperitoneal injection of various dosage of exotoxin A. Results...

  19. Compromised Host Defense on Pseudomonas aeruginosa Biofilms: Characterization of Neutrophil and Biofilm Interactions

    National Research Council Canada - National Science Library

    Jesaitis, Algirdas J; Franklin, Michael J; Berglund, Deborah; Sasaki, Maiko; Lord, Connie I; Bleazard, Justin B; Duffy, James E; Beyenal, Haluk; Lewandowski, Zbigniew

    2003-01-01

    Departments of * Microbiology, Civil Engineering, Chemical Engineering, and Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717 Pseudomonas aeruginosa is an opportunistic pathogen that forms...

  20. Kin cell lysis is a danger signal that activates antibacterial pathways of Pseudomonas aeruginosa

    Science.gov (United States)

    LeRoux, Michele; Kirkpatrick, Robin L; Montauti, Elena I; Tran, Bao Q; Peterson, S Brook; Harding, Brittany N; Whitney, John C; Russell, Alistair B; Traxler, Beth; Goo, Young Ah; Goodlett, David R; Wiggins, Paul A; Mougous, Joseph D

    2015-01-01

    The perception and response to cellular death is an important aspect of multicellular eukaryotic life. For example, damage-associated molecular patterns activate an inflammatory cascade that leads to removal of cellular debris and promotion of healing. We demonstrate that lysis of Pseudomonas aeruginosa cells triggers a program in the remaining population that confers fitness in interspecies co-culture. We find that this program, termed P. aeruginosa response to antagonism (PARA), involves rapid deployment of antibacterial factors and is mediated by the Gac/Rsm global regulatory pathway. Type VI secretion, and, unexpectedly, conjugative type IV secretion within competing bacteria, induce P. aeruginosa lysis and activate PARA, thus providing a mechanism for the enhanced capacity of P. aeruginosa to target bacteria that elaborate these factors. Our finding that bacteria sense damaged kin and respond via a widely distributed pathway to mount a complex response raises the possibility that danger sensing is an evolutionarily conserved process. DOI: http://dx.doi.org/10.7554/eLife.05701.001 PMID:25643398

  1. The salicylidene acylhydrazide INP0341 attenuates Pseudomonas aeruginosa virulence in vitro and in vivo.

    Science.gov (United States)

    Uusitalo, Pia; Hägglund, Ulrik; Rhöös, Elin; Scherman Norberg, Henrik; Elofsson, Mikael; Sundin, Charlotta

    2017-08-01

    Pseudomonas aeruginosa is an opportunistic pathogen that can be very hard to treat because of high resistance to different antibiotics and alternative treatment regimens are greatly needed. An alternative or a complement to traditional antibiotic is to inhibit virulence of the bacteria. The salicylidene acylhydrazide, INP0341, belongs to a class of compounds that has previously been shown to inhibit virulence in a number of Gram-negative bacteria. In this study, the virulence blocking effect of INP0341 on P. aeruginosa was studied in vitro and in vivo. Two important and closely related virulence system were examined, the type III secretion system (T3SS) that translocates virulence effectors into the cytosol of the host cell to evade immune defense and facilitate colonization and the flagella system, needed for motility and biofilm formation. INP0341 was shown to inhibit expression and secretion of the T3SS toxin exoenzyme S (ExoS) and to prevent bacterial motility on agar plates and biofilm formation. In addition, INP0341 showed an increased survival of P. aeruginosa-infected mice. In conclusion, INP0341 attenuates P. aeruginosa virulence.

  2. Genetic and Functional Diversity of Pseudomonas aeruginosa Lipopolysaccharide

    Science.gov (United States)

    Lam, Joseph S.; Taylor, Véronique L.; Islam, Salim T.; Hao, Youai; Kocíncová, Dana

    2011-01-01

    Lipopolysccharide (LPS) is an integral component of the Pseudomonas aeruginosa cell envelope, occupying the outer leaflet of the outer membrane in this Gram-negative opportunistic pathogen. It is important for bacterium–host interactions and has been shown to be a major virulence factor for this organism. Structurally, P. aeruginosa LPS is composed of three domains, namely, lipid A, core oligosaccharide, and the distal O antigen (O-Ag). Most P. aeruginosa strains produce two distinct forms of O-Ag, one a homopolymer of D-rhamnose that is a common polysaccharide antigen (CPA, formerly termed A band), and the other a heteropolymer of three to five distinct (and often unique dideoxy) sugars in its repeat units, known as O-specific antigen (OSA, formerly termed B band). Compositional differences in the O units among the OSA from different strains form the basis of the International Antigenic Typing Scheme for classification via serotyping of different strains of P. aeruginosa. The focus of this review is to provide state-of-the-art knowledge on the genetic and resultant functional diversity of LPS produced by P. aeruginosa. The underlying factors contributing to this diversity will be thoroughly discussed and presented in the context of its contributions to host–pathogen interactions and the control/prevention of infection. PMID:21687428

  3. Rapid diagnosis of Pseudomonas aeruginosa urinary tract infections by radioimmunoassay.

    Science.gov (United States)

    Kohler, R B; Wheat, L J; White, A

    1979-01-01

    A solid-phase radioimmunoassay designed to detect serotype 6 Pseudomonas aeruginosa antigens was evaluated for its ability to rapidly diagnose urinary tract infections. Twelve P. aeruginosa serotypes were easily differentiated in the assay from eight other gram-negative bacterial species. During log-phase growth, the assay detected antigens in culture when approximately 10(6) or more serotype 6 P. aeruginosa organisms were present. Both cell-associated and solubilized antigens were detected. The assay detected antigens in 13 of 17 urine specimens which grew greater than 10(5) P. aeruginosa, 3 of 38 which grew other gram-negative rods, and none of 83 with no growth. Two of the three positive specimens from the other gram-negative rod group probably also contained P. aeruginosa. No preincubation of the urine specimens was required, and results were available within 2.5 h. The assay represents an improvement over other procedures for rapidly diagnosing urinary tract infections in that it allows diagnosis by species and should be adaptable to semiautomation. PMID:107191

  4. A network biology approach to denitrification in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Seda Arat

    Full Text Available Pseudomonas aeruginosa is a metabolically flexible member of the Gammaproteobacteria. Under anaerobic conditions and the presence of nitrate, P. aeruginosa can perform (complete denitrification, a respiratory process of dissimilatory nitrate reduction to nitrogen gas via nitrite (NO2, nitric oxide (NO and nitrous oxide (N2O. This study focuses on understanding the influence of environmental conditions on bacterial denitrification performance, using a mathematical model of a metabolic network in P. aeruginosa. To our knowledge, this is the first mathematical model of denitrification for this bacterium. Analysis of the long-term behavior of the network under changing concentration levels of oxygen (O2, nitrate (NO3, and phosphate (PO4 suggests that PO4 concentration strongly affects denitrification performance. The model provides three predictions on denitrification activity of P. aeruginosa under various environmental conditions, and these predictions are either experimentally validated or supported by pertinent biological literature. One motivation for this study is to capture the effect of PO4 on a denitrification metabolic network of P. aeruginosa in order to shed light on mechanisms for greenhouse gas N2O accumulation during seasonal oxygen depletion in aquatic environments such as Lake Erie (Laurentian Great Lakes, USA. Simulating the microbial production of greenhouse gases in anaerobic aquatic systems such as Lake Erie allows a deeper understanding of the contributing environmental effects that will inform studies on, and remediation strategies for, other hypoxic sites worldwide.

  5. Pyocyanin promotes extracellular DNA release in Pseudomonas aeruginosa.

    Science.gov (United States)

    Das, Theerthankar; Manefield, Mike

    2012-01-01

    Bacterial adhesion and biofilm formation are both dependent on the production of extracellular polymeric substances (EPS) mainly composed of polysaccharides, proteins, lipids, and extracellular DNA (eDNA). eDNA promotes biofilm establishment in a wide range of bacterial species. In Pseudomonas aeruginosa eDNA is major component of biofilms and is essential for biofilm formation and stability. In this study we report that production of pyocyanin in P. aeruginosa PAO1 and PA14 batch cultures is responsible for promotion of eDNA release. A phzSH mutant of P. aeruginosa PAO1 that overproduces pyocyanin displayed enhanced hydrogen peroxide (H(2)O(2)) generation, cell lysis, and eDNA release in comparison to its wildtype strain. A ΔphzA-G mutant of P. aeruginosa PA14 deficient in pyocyanin production generated negligible amounts of H(2)O(2) and released less eDNA in comparison to its wildtype counterpart. Exogenous addition of pyocyanin or incubation with H(2)O(2) was also shown to promote eDNA release in low pyocyanin producing (PAO1) and pyocynain deficient (PA14) strains. Based on these data and recent findings in the biofilm literature, we propose that the impact of pyocyanin on biofilm formation in P. aeruginosa occurs via eDNA release through H(2)O(2) mediated cell lysis.

  6. Pyocyanin promotes extracellular DNA release in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Theerthankar Das

    Full Text Available Bacterial adhesion and biofilm formation are both dependent on the production of extracellular polymeric substances (EPS mainly composed of polysaccharides, proteins, lipids, and extracellular DNA (eDNA. eDNA promotes biofilm establishment in a wide range of bacterial species. In Pseudomonas aeruginosa eDNA is major component of biofilms and is essential for biofilm formation and stability. In this study we report that production of pyocyanin in P. aeruginosa PAO1 and PA14 batch cultures is responsible for promotion of eDNA release. A phzSH mutant of P. aeruginosa PAO1 that overproduces pyocyanin displayed enhanced hydrogen peroxide (H(2O(2 generation, cell lysis, and eDNA release in comparison to its wildtype strain. A ΔphzA-G mutant of P. aeruginosa PA14 deficient in pyocyanin production generated negligible amounts of H(2O(2 and released less eDNA in comparison to its wildtype counterpart. Exogenous addition of pyocyanin or incubation with H(2O(2 was also shown to promote eDNA release in low pyocyanin producing (PAO1 and pyocynain deficient (PA14 strains. Based on these data and recent findings in the biofilm literature, we propose that the impact of pyocyanin on biofilm formation in P. aeruginosa occurs via eDNA release through H(2O(2 mediated cell lysis.

  7. The effect of alginate lyase on the gentamicin resistance of Pseudomonas aeruginosa in mucoid biofilms.

    Science.gov (United States)

    Germoni, L A P; Bremer, P J; Lamont, I L

    2016-07-01

    Pseudomonas aeruginosa can secrete large amounts of alginate during chronic infections and this has been associated with high resistance to antibiotics. The major aim of this study was to investigate whether degradation of extracellular alginate by alginate lyase would increase the sensitivity of Ps. aeruginosa to gentamicin, an aminoglycoside antibiotic. Degradation of alginate from Ps. aeruginosa was monitored using a spectrometric assay. Alginate lyase depolymerized alginate, but calcium and zinc cations at concentrations found in the cystic fibrosis lung reduced enzyme activity. Biofilms formed on agar were partially degraded by alginate lyase, but staining with crystal violet showed that the biomass of biofilms grown in liquid was not significantly affected by the enzyme. Viability testing showed that the sensitivity to gentamicin of biofilm bacteria and of bacteria released from biofilms was unaffected by alginate lyase. Our results show that at least under the conditions used here alginate lyase does not affect gentamicin resistance of Ps. aeruginosa. Our study indicates that alginate does not contribute to resistance to gentamicin and so does not provide support for the concept of treating patients with alginate lyase in order to increase the antibiotic sensitivity of Ps. aeruginosa. © 2016 The Society for Applied Microbiology.

  8. The Pseudomonas aeruginosa AlgZR two-component system coordinates multiple phenotypes

    Science.gov (United States)

    Okkotsu, Yuta; Little, Alexander S.; Schurr, Michael J.

    2014-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that causes a multitude of infections. These infections can occur at almost any site in the body and are usually associated with a breach of the innate immune system. One of the prominent sites where P. aeruginosa causes chronic infections is within the lungs of cystic fibrosis patients. P. aeruginosa uses two-component systems that sense environmental changes to differentially express virulence factors that cause both acute and chronic infections. The P. aeruginosa AlgZR two component system is one of its global regulatory systems that affects the organism's fitness in a broad manner. This two-component system is absolutely required for two P. aeruginosa phenotypes: twitching motility and alginate production, indicating its importance in both chronic and acute infections. Additionally, global transcriptome analyses indicate that it regulates the expression of many different genes, including those associated with quorum sensing, type IV pili, type III secretion system, anaerobic metabolism, cyanide and rhamnolipid production. This review examines the complex AlgZR regulatory network, what is known about the structure and function of each protein, and how it relates to the organism's ability to cause infections. PMID:24999454

  9. Activation of the Epithelial Sodium Channel (ENaC) by the Alkaline Protease from Pseudomonas aeruginosa*

    Science.gov (United States)

    Butterworth, Michael B.; Zhang, Liang; Heidrich, Elisa M.; Myerburg, Michael M.; Thibodeau, Patrick H.

    2012-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that significantly contributes to the mortality of patients with cystic fibrosis. Chronic infection by Pseudomonas induces sustained immune and inflammatory responses and damage to the airway. The ability of Pseudomonas to resist host defenses is aided, in part, by secreted proteases, which act as virulence factors in multiple modes of infection. Recent studies suggest that misregulation of protease activity in the cystic fibrosis lung may alter fluid secretion and pathogen clearance by proteolytic activation of the epithelial sodium channel (ENaC). To evaluate the possibility that proteolytic activation of ENaC may contribute to the virulence of Pseudomonas, primary human bronchial epithelial cells were exposed to P. aeruginosa and ENaC function was assessed by short circuit current measurements. Apical treatment with a strain known to express high levels of alkaline protease (AP) resulted in an increase in basal ENaC current and a loss of trypsin-inducible ENaC current, consistent with sustained activation of ENaC. To further characterize this AP-induced ENaC activation, AP was purified, and its folding, activity, and ability to activate ENaC were assessed. AP folding was efficient under pH and calcium conditions thought to exist in the airway surface liquid of normal and cystic fibrosis (CF) lungs. Short circuit measurements of ENaC in polarized monolayers indicated that AP activated ENaC in immortalized cell lines as well as post-transplant, primary human bronchial epithelial cells from both CF and non-CF patients. This activation was mapped to the γ-subunit of ENaC. Based on these data, patho-mechanisms associated with AP in the CF lung are proposed wherein secretion of AP leads to decreased airway surface liquid volume and a corresponding decrease in mucocilliary clearance of pulmonary pathogens. PMID:22859302

  10. Pseudomonas aeruginosa Lifestyle: A Paradigm for Adaptation, Survival, and Persistence

    Science.gov (United States)

    Moradali, M. Fata; Ghods, Shirin; Rehm, Bernd H. A.

    2017-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen affecting immunocompromised patients. It is known as the leading cause of morbidity and mortality in cystic fibrosis (CF) patients and as one of the leading causes of nosocomial infections. Due to a range of mechanisms for adaptation, survival and resistance to multiple classes of antibiotics, infections by P. aeruginosa strains can be life-threatening and it is emerging worldwide as public health threat. This review highlights the diversity of mechanisms by which P. aeruginosa promotes its survival and persistence in various environments and particularly at different stages of pathogenesis. We will review the importance and complexity of regulatory networks and genotypic-phenotypic variations known as adaptive radiation by which P. aeruginosa adjusts physiological processes for adaptation and survival in response to environmental cues and stresses. Accordingly, we will review the central regulatory role of quorum sensing and signaling systems by nucleotide-based second messengers resulting in different lifestyles of P. aeruginosa. Furthermore, various regulatory proteins will be discussed which form a plethora of controlling systems acting at transcriptional level for timely expression of genes enabling rapid responses to external stimuli and unfavorable conditions. Antibiotic resistance is a natural trait for P. aeruginosa and multiple mechanisms underlying different forms of antibiotic resistance will be discussed here. The importance of each mechanism in conferring resistance to various antipseudomonal antibiotics and their prevalence in clinical strains will be described. The underlying principles for acquiring resistance leading pan-drug resistant strains will be summarized. A future outlook emphasizes the need for collaborative international multidisciplinary efforts to translate current knowledge into strategies to prevent and treat P. aeruginosa infections while reducing the rate of antibiotic resistance

  11. Specific IgA against Pseudomonas aeruginosa in severe COPD

    Science.gov (United States)

    Millares, Laura; Martí, Sara; Ardanuy, Carmen; Liñares, Josefina; Santos, Salud; Dorca, Jordi; García-Nuñez, Marian; Quero, Sara; Monsó, Eduard

    2017-01-01

    Background The bronchial mucosa is protected by a specialized immune system focused on the prevention of colonization and infection by potentially pathogenic microorganisms (PPMs). Immunoglobulin A (IgA) is the principal antibody involved in this mechanism. A defective immune barrier may facilitate the recurrent presence of PPMs in COPD. Purpose The aim of this study was to determine IgA-mediated bronchial specific immune responses against Pseudomonas aeruginosa in stable patients with severe disease. Methods COPD patients with good-quality sputum samples obtained during stability were included and classified according to the presence or absence of chronic bronchial colonization by P. aeruginosa. Levels of specific IgA for P. aeruginosa in sputum were determined by ELISA and expressed as ratios, using the pooled level of 10 healthy subjects as reference (optical density450 patient/control). Results Thirty-six stable COPD patients were included, 15 of whom had chronic colonization by P. aeruginosa. Levels of specific IgA against P. aeruginosa in stable non-colonized patients were lower than those in healthy subjects (IgA ratio: median =0.15 [interquartile range {IQR} 0.05–0.36]). Colonized patients had higher levels, (1.56 [IQR 0.59–2.79]) (p<0.001, Mann–Whitney U test), with figures equivalent but not exceeding the reference value. Conclusion IgA-based immune response against P. aeruginosa was low in severe COPD patients. Levels of specific IgA against this microorganism were higher in colonized patients, but did not attain clear-cut levels above the reference. An impaired local response against P. aeruginosa may favor chronic colonization and recurrent infections in severe COPD. PMID:29033561

  12. Enterobacteria secrete an inhibitor of Pseudomonas virulence during clinical bacteriuria.

    Science.gov (United States)

    Ohlemacher, Shannon I; Giblin, Daryl E; d'Avignon, D André; Stapleton, Ann E; Trautner, Barbara W; Henderson, Jeffrey P

    2017-11-01

    Escherichia coli and other Enterobacteriaceae are among the most common pathogens of the human urinary tract. Among the genetic gains of function associated with urinary E. coli isolates is the Yersinia high pathogenicity island (HPI), which directs the biosynthesis of yersiniabactin (Ybt), a virulence-associated metallophore. Using a metabolomics approach, we found that E. coli and other Enterobacteriaceae expressing the Yersinia HPI also secrete escherichelin, a second metallophore whose chemical structure matches a known synthetic inhibitor of the virulence-associated pyochelin siderophore system in Pseudomonas aeruginosa. We detected escherichelin during clinical E. coli urinary tract infection (UTI) and experimental human colonization with a commensal, potentially probiotic E. coli bacteriuria strain. Escherichelin production by colonizing enterobacteria may help human hosts resist opportunistic infections by Pseudomonas and other pyochelin-expressing bacteria. This siderophore-based mechanism of microbial antagonism may be one of many elements contributing to the protective effects of the human microbiome. Future UTI-preventive probiotic strains may benefit by retaining the escherichelin biosynthetic capacity of the Yersinia HPI while eliminating the Ybt biosynthetic capacity.

  13. Peroxisome proliferator-activated receptor-γ agonists attenuate biofilm formation by Pseudomonas aeruginosa.

    Science.gov (United States)

    Bedi, Brahmchetna; Maurice, Nicholas M; Ciavatta, Vincent T; Lynn, K Sabrina; Yuan, Zhihong; Molina, Samuel A; Joo, Myungsoo; Tyor, William R; Goldberg, Joanna B; Koval, Michael; Hart, C Michael; Sadikot, Ruxana T

    2017-08-01

    Pseudomonas aeruginosa is a significant contributor to recalcitrant multidrug-resistant infections, especially in immunocompromised and hospitalized patients. The pathogenic profile of P. aeruginosa is related to its ability to secrete a variety of virulence factors and to promote biofilm formation. Quorum sensing (QS) is a mechanism wherein P. aeruginosa secretes small diffusible molecules, specifically acyl homo serine lactones, such as N-(3-oxo-dodecanoyl)-l-homoserine lactone (3O-C12-HSL), that promote biofilm formation and virulence via interbacterial communication. Strategies that strengthen the host's ability to inhibit bacterial virulence would enhance host defenses and improve the treatment of resistant infections. We have recently shown that peroxisome proliferator-activated receptor γ (PPARγ) agonists are potent immunostimulators that play a pivotal role in host response to virulent P. aeruginosa Here, we show that QS genes in P. aeruginosa (strain PAO1) and 3O-C12-HSL attenuate PPARγ expression in bronchial epithelial cells. PAO1 and 3O-C12-HSL induce barrier derangements in bronchial epithelial cells by lowering the expression of junctional proteins, such as zonula occludens-1, occludin, and claudin-4. Expression of these proteins was restored in cells that were treated with pioglitazone, a PPARγ agonist, before infection with PAO1 and 3O-C12-HSL. Barrier function and bacterial permeation studies that have been performed in primary human epithelial cells showed that PPARγ agonists are able to restore barrier integrity and function that are disrupted by PAO1 and 3O-C12-HSL. Mechanistically, we show that these effects are dependent on the induction of paraoxonase-2, a QS hydrolyzing enzyme, that mitigates the effects of QS molecules. Importantly, our data show that pioglitazone, a PPARγ agonist, significantly inhibits biofilm formation on epithelial cells by a mechanism that is mediated via paraoxonase-2. These findings elucidate a novel role for

  14. PURIFIKASI DAN KARAKTERISASI PROTEASE DARI BAKTERI PATOGEN Pseudomonas aeruginosa [Purification and Characterization of Protease from Pathogenic Bacteria Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Ace Baehaki1

    2008-06-01

    Full Text Available In the last decade, concern on protease as medical target for overcoming bacterial diseases and viral diseases has been rapidly increased because of the obvious involvement of this enzyme in the molecular of the diseases. The purpose of this research was to purify and characterize protease from pathogenic bacteria Pseudomonas aeruginosa. The bacteria were grown in media containing triptone 1%, NaCl 1% and Yeast extract 0,5%. Protease of P.aeruginosa was purified using column chromatography with Sephadex G-100 gel. There were three peaks of enzyme protein, which were detected on fractions 14, 17 and 30. The optimum pH of the extracelluler protease from P. aeruginosa was 8. The optimum temperature of P.aeruginosa protease was 300C. Fe3+ (1dan 5 mM was strong activator and Co2+ was strong inhibitor. Study on the effect of metals ion and spesific inhibitors indicated that protease from P. aeruginosa was serin metaloprotease. The apparent moleculer weights, as determined by SDS-PAGE and zymogram technique, 36 kD and 42 kD.

  15. Expression, purification, and characterization of formaldehyde dehydrogenase from Pseudomonas aeruginosa.

    Science.gov (United States)

    Zhang, Wangluo; Chen, Shuai; Liao, Yuanping; Wang, Dingli; Ding, Jianfeng; Wang, Yingming; Ran, Xiaoyuan; Lu, Daru; Zhu, Huaxing

    2013-12-01

    As a member of zinc-containing medium-chain alcohol dehydrogenase family, formaldehyde dehydrogenase (FDH) can oxidize toxic formaldehyde to less active formate with NAD(+) as a cofactor and exists in both prokaryotes and eukaryotes. Most FDHs are well known to be glutathione-dependent in the catalysis of formaldehyde oxidation, but the enzyme from Pseudomonas putida is an exception, which is independent of glutathione. To identify novel glutathione-independent FDHs from other bacterial strains and facilitate the corresponding structural and enzymatic studies, high-level soluble expression and efficient purification of these enzymes need to be achieved. Here, we present molecular cloning, expression, and purification of the FDH from Pseudomonas aeruginosa, which is a Gram-negative pathogenic bacterium causing opportunistic human infection. The FDH of P. aeruginosa shows high sequence identity (87.97%) with that of P. putida. Our results indicated that coexpression with molecular chaperones GroES, GroEL, and Tig has significantly attenuated inclusion body formation and improved the solubility of the recombinant FDH in Escherichiacoli cells. A purification protocol including three chromatographic steps was also established to isolate the recombinant FDH to homogeneity with a yield of ∼3.2 mg from 1L of cell culture. The recombinant P. aeruginosa FDH was properly folded and biologically functional, as demonstrated by the mass spectrometric, crystallographic, and enzymatic characterizations of the purified proteins. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Functional study of elafin cleaved by Pseudomonas aeruginosa metalloproteinases

    Science.gov (United States)

    Guyot, Nicolas; Bergsson, Gudmundur; Butler, Marcus W.; Greene, Catherine M.; Weldon, Sinead; Kessler, Efrat; Levine, Rodney L.; O’Neill, Shane J.; Taggart, Clifford C.; McElvaney, Noel G.

    2012-01-01

    Elafin is a 6 kDa innate immune protein present at several epithelial surfaces including the pulmonary epithelium. It is a canonical protease inhibitor of two neutrophil serine proteases (neutrophil elastase (NE) and proteinase 3) with the capacity to covalently bind extracellular matrix proteins by transglutamination. In addition to these properties, elafin also possesses antimicrobial and immunomodulatory activities. The aim of the present study was to investigate the effect of Pseudomonas aeruginosa proteases on elafin function. We found that P. aeruginosa PAO1-conditioned medium and two purified Pseudomonas metalloproteases, pseudolysin (elastase) and aeruginolysin (alkaline protease), were able to cleave recombinant elafin. Pseudolysin was shown to inactivate the anti-NE activity of elafin by cleaving its protease-binding loop. Interestingly, antibacterial properties of elafin against PAO1 were found to be unaffected after pseudolysin treatment. In contrast to pseudolysin, aeruginolysin failed to inactivate the inhibitory properties of elafin against NE. Aeruginolysin cleaved elafin at the amino-terminal Lys6-Gly7 peptide bond resulting in a decreased ability to covalently bind purified fibronectin following transglutaminase activity. In conclusion, this study provides evidences that elafin is susceptible to proteolytic cleavage at alternative sites by P. aeruginosa metalloproteinases, which can affect different biological functions of elafin. PMID:20370321

  17. Functional study of elafin cleaved by Pseudomonas aeruginosa metalloproteinases.

    LENUS (Irish Health Repository)

    Guyot, Nicolas

    2010-06-01

    Elafin is a 6-kDa innate immune protein present at several epithelial surfaces including the pulmonary epithelium. It is a canonical protease inhibitor of two neutrophil serine proteases [neutrophil elastase (NE) and proteinase 3] with the capacity to covalently bind extracellular matrix proteins by transglutamination. In addition to these properties, elafin also possesses antimicrobial and immunomodulatory activities. The aim of the present study was to investigate the effect of Pseudomonas aeruginosa proteases on elafin function. We found that P. aeruginosa PAO1-conditioned medium and two purified Pseudomonas metalloproteases, pseudolysin (elastase) and aeruginolysin (alkaline protease), are able to cleave recombinant elafin. Pseudolysin was shown to inactivate the anti-NE activity of elafin by cleaving its protease-binding loop. Interestingly, antibacterial properties of elafin against PAO1 were found to be unaffected after pseudolysin treatment. In contrast to pseudolysin, aeruginolysin failed to inactivate the inhibitory properties of elafin against NE. Aeruginolysin cleaves elafin at the amino-terminal Lys6-Gly7 peptide bond, resulting in a decreased ability to covalently bind purified fibronectin following transglutaminase activity. In conclusion, this study provides evidence that elafin is susceptible to proteolytic cleavage at alternative sites by P. aeruginosa metalloproteinases, which can affect different biological functions of elafin.

  18. Monocyte Profiles in Critically Ill Patients With Pseudomonas Aeruginosa Sepsis

    Science.gov (United States)

    2017-02-02

    Pseudomonas Infections; Pseudomonas Septicemia; Pseudomonas; Pneumonia; Pseudomonal Bacteraemia; Pseudomonas Urinary Tract Infection; Pseudomonas Gastrointestinal Tract Infection; Sepsis; Sepsis, Severe; Critically Ill

  19. Flexible survival strategies of Pseudomonas aeruginosa in biofilms result in increased fitness compared with Candida albicans.

    Science.gov (United States)

    Purschke, Frauke Gina; Hiller, Ekkehard; Trick, Iris; Rupp, Steffen

    2012-12-01

    The majority of microorganisms persist in nature as surface-attached communities often surrounded by an extracellular matrix, called biofilms. Most natural biofilms are not formed by a single species but by multiple species. Microorganisms not only cooperate as in some multispecies biofilms but also compete for available nutrients. The Gram-negative bacterium Pseudomonas aeruginosa and the polymorphic fungus Candida albicans are two opportunistic pathogens that are often found coexisting in a human host. Several models of mixed biofilms have been reported for these organisms showing antagonistic behavior. To investigate the interaction of P. aeruginosa and C. albicans in more detail, we analyzed the secretome of single and mixed biofilms of both organisms using MALDI-TOF MS/MS at several time points. Overall 247 individual proteins were identified, 170 originated from P. aeruginosa and 77 from C. albicans. Only 39 of the 131 in mixed biofilms identified proteins were assigned to the fungus whereby the remaining 92 proteins belonged to P. aeruginosa. In single-species biofilms, both organisms showed a higher diversity of proteins with 73 being assigned to C. albicans and 154 to P. aeruginosa. Most interestingly, P. aeruginosa in the presence of C. albicans secreted 16 proteins in significantly higher amounts or exclusively among other virulence factors such as exotoxin A and iron acquisition systems. In addition, the high affinity iron-binding siderophore pyoverdine was identified in mixed biofilms but not in bacterial biofilms, indicating that P. aeruginosa increases its capability to sequester iron in competition with C. albicans. In contrast, C. albicans metabolism was significantly reduced, including a reduction in detectable iron acquisition proteins. The results obtained in this study show that microorganisms not only compete with the host for essential nutrients but also strongly with the present microflora in order to gain a competitive advantage.

  20. Flexible Survival Strategies of Pseudomonas aeruginosa in Biofilms Result in Increased Fitness Compared with Candida albicans *

    Science.gov (United States)

    Purschke, Frauke Gina; Hiller, Ekkehard; Trick, Iris; Rupp, Steffen

    2012-01-01

    The majority of microorganisms persist in nature as surface-attached communities often surrounded by an extracellular matrix, called biofilms. Most natural biofilms are not formed by a single species but by multiple species. Microorganisms not only cooperate as in some multispecies biofilms but also compete for available nutrients. The Gram-negative bacterium Pseudomonas aeruginosa and the polymorphic fungus Candida albicans are two opportunistic pathogens that are often found coexisting in a human host. Several models of mixed biofilms have been reported for these organisms showing antagonistic behavior. To investigate the interaction of P. aeruginosa and C. albicans in more detail, we analyzed the secretome of single and mixed biofilms of both organisms using MALDI-TOF MS/MS at several time points. Overall 247 individual proteins were identified, 170 originated from P. aeruginosa and 77 from C. albicans. Only 39 of the 131 in mixed biofilms identified proteins were assigned to the fungus whereby the remaining 92 proteins belonged to P. aeruginosa. In single-species biofilms, both organisms showed a higher diversity of proteins with 73 being assigned to C. albicans and 154 to P. aeruginosa. Most interestingly, P. aeruginosa in the presence of C. albicans secreted 16 proteins in significantly higher amounts or exclusively among other virulence factors such as exotoxin A and iron acquisition systems. In addition, the high affinity iron-binding siderophore pyoverdine was identified in mixed biofilms but not in bacterial biofilms, indicating that P. aeruginosa increases its capability to sequester iron in competition with C. albicans. In contrast, C. albicans metabolism was significantly reduced, including a reduction in detectable iron acquisition proteins. The results obtained in this study show that microorganisms not only compete with the host for essential nutrients but also strongly with the present microflora in order to gain a competitive advantage. PMID

  1. Strain-dependent induction of neutrophil histamine production and cell death by Pseudomonas aeruginosa

    Science.gov (United States)

    Xu, Xiang; Zhang, Hong; Song, Yuanlin; Lynch, Susan V.; Lowell, Clifford A.; Wiener-Kronish, Jeanine P.; Caughey, George H.

    2012-01-01

    Airway diseases often feature persistent neutrophilic inflammation and infection. In cystic fibrosis bronchitis, for example, Pseudomonas aeruginosa is isolated frequently. Previously, this laboratory revealed that neutrophils become major sources of histamine in mice with tracheobronchitis caused by the wall-less bacterium Mycoplasma pulmonis. To test the hypothesis that more-broadly pathogenic P. aeruginosa (which expresses cell wall-associated LPS and novel toxins) has similar effects, we incubated naïve mouse neutrophils with two strains of P. aeruginosa. Strain PAO1 greatly increased neutrophil histamine content and secretion, whereas strain PA103 depressed histamine production by killing neutrophils. The histamine-stimulating capacity of PAO1, but not PA103-mediated toxicity, persisted in heat-killed organisms. In PAO1-infected mice, lung and neutrophil histamine content increased. However, PAO1 did not alter production by mast cells (classical histamine reservoirs), which also resisted PA103 toxicity. To explore mechanisms of neutrophil-selective induction, we measured changes in mRNA encoding histidine decarboxylase (rate-limiting for histamine synthesis), probed involvement of endotoxin-TLR pathways in Myd88-deficient neutrophils, and examined contributions of pyocyanin and exotoxins. Results revealed that PAO1 increased histamine production by up-regulating histidine decarboxylase mRNA via pathways largely independent of TLR, pyocyanin, and type III secretion system exotoxins. PAO1 also increased histidine decarboxylase mRNA in neutrophils purified from infected lung. Stimulation required direct contact with neutrophils and was blocked by phagocytosis inhibitor cytochalasin D. In summary, Pseudomonas-augmented histamine production by neutrophils is strain-dependent in vitro and likely mediated by up-regulation of histidine decarboxylase. These findings raise the possibility that Pseudomonas-stimulated neutrophils can enhance airway inflammation by

  2. Raloxifene attenuates Pseudomonas aeruginosa pyocyanin production and virulence.

    Science.gov (United States)

    Ho Sui, Shannan J; Lo, Raymond; Fernandes, Aalton R; Caulfield, Mackenzie D G; Lerman, Joshua A; Xie, Lei; Bourne, Philip E; Baillie, David L; Brinkman, Fiona S L

    2012-09-01

    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. Copyright © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  3. Prevalence and analysis of Pseudomonas aeruginosa in chinchillas

    Directory of Open Access Journals (Sweden)

    Aoyama Naoki

    2010-11-01

    Full Text Available Abstract Background Chinchillas (Chinchilla laniger are popular as pets and are often used as laboratory animals for various studies. Pseudomonas aeruginosa is a major infectious agent that causes otitis media, pneumonia, septicaemia enteritis, and sudden death in chinchillas. This bacterium is also a leading cause of nosocomial infections in humans. To prevent propagation of P. aeruginosa infection among humans and animals, detailed characteristics of the isolates, including antibiotic susceptibility and genetic features, are needed. In this study, we surveyed P. aeruginosa distribution in chinchillas bred as pets or laboratory animals. We also characterized the isolates from these chinchillas by testing for antibiotic susceptibility and by gene analysis. Results P. aeruginosa was isolated from 41.8% of the 67 chinchillas included in the study. Slide agglutination and pulsed-field gel electrophoresis discriminated 5 serotypes and 7 unique patterns, respectively. For the antibiotic susceptibility test, 40.9% of isolates were susceptible to gentamicin, 77.3% to ciprofloxacin, 77.3% to imipenem, and 72.7% to ceftazidime. DNA analyses confirmed that none of the isolates contained the gene encoding extended-spectrum β-lactamases; however, 2 of the total 23 isolates were found to have a gene similar to the pilL gene that has been identified in the pathogenicity island of a clinical isolate of P. aeruginosa. Conclusions P. aeruginosa is widely spread in chinchillas, including strains with reduced susceptibility to the antibiotics and highly virulent strains. The periodic monitoring should be performed to help prevent the propagation of this pathogen and reduce the risk of infection from chinchillas to humans.

  4. Identification of small molecule inhibitors of Pseudomonas aeruginosa exoenzyme S using a yeast phenotypic screen.

    Directory of Open Access Journals (Sweden)

    Anthony Arnoldo

    2008-02-01

    Full Text Available Pseudomonas aeruginosa is an opportunistic human pathogen that is a key factor in the mortality of cystic fibrosis patients, and infection represents an increased threat for human health worldwide. Because resistance of Pseudomonas aeruginosa to antibiotics is increasing, new inhibitors of pharmacologically validated targets of this bacterium are needed. Here we demonstrate that a cell-based yeast phenotypic assay, combined with a large-scale inhibitor screen, identified small molecule inhibitors that can suppress the toxicity caused by heterologous expression of selected Pseudomonas aeruginosa ORFs. We identified the first small molecule inhibitor of Exoenzyme S (ExoS, a toxin involved in Type III secretion. We show that this inhibitor, exosin, modulates ExoS ADP-ribosyltransferase activity in vitro, suggesting the inhibition is direct. Moreover, exosin and two of its analogues display a significant protective effect against Pseudomonas infection in vivo. Furthermore, because the assay was performed in yeast, we were able to demonstrate that several yeast homologues of the known human ExoS targets are likely ADP-ribosylated by the toxin. For example, using an in vitro enzymatic assay, we demonstrate that yeast Ras2p is directly modified by ExoS. Lastly, by surveying a collection of yeast deletion mutants, we identified Bmh1p, a yeast homologue of the human FAS, as an ExoS cofactor, revealing that portions of the bacterial toxin mode of action are conserved from yeast to human. Taken together, our integrated cell-based, chemical-genetic approach demonstrates that such screens can augment traditional drug screening approaches and facilitate the discovery of new compounds against a broad range of human pathogens.

  5. Candida albicans and Pseudomonas aeruginosa Interaction, with Focus on the Role of Eicosanoids

    Science.gov (United States)

    Fourie, Ruan; Ells, Ruan; Swart, Chantel W.; Sebolai, Olihile M.; Albertyn, Jacobus; Pohl, Carolina H.

    2016-01-01

    Candida albicans is commonly found in mixed infections with Pseudomonas aeruginosa, especially in the lungs of cystic fibrosis (CF) patients. Both of these opportunistic pathogens are able to form resistant biofilms and frequently infect immunocompromised individuals. The interaction between these two pathogens, which includes physical interaction as well as secreted factors, is mainly antagonistic. In addition, research suggests considerable interaction with their host, especially with immunomodulatory lipid mediators, termed eicosanoids. Candida albicans and Pseudomonas aeruginosa are both able to utilize arachidonic acid (AA), liberated from the host cells during infection, to form eicosanoids. The production of these eicosanoids, such as Prostaglandin E2, by the host and the pathogens may affect the dynamics of polymicrobial infection and the outcome of infections. It is of considerable importance to elucidate the role of host-produced, as well as pathogen-produced eicosanoids in polymicrobial infection. This review will focus on in vitro as well as in vivo interaction between C. albicans and P. aeruginosa, paying special attention to the role of eicosanoids in the cross-talk between host and the pathogens. PMID:26955357

  6. De aanwezigheid van Pseudomonas aeruginosa in circulatiebaden in relatie tot de controle volgens de Wet Hygiene en Veiligheid Zwemgelegenheden

    NARCIS (Netherlands)

    Schijven JF; Havelaar AH

    1989-01-01

    Door 8 externe laboratoria werden 133 buitenbaden en 340 binnenbaden onderzocht op aanwezigheid van Pseudomonas aeruginosa. Het betrof circulatiebaden, die periodiek volgens de eisen van het Besluit Hygiene en Veiligheid Zwemgelegenheden (BHVZ) werden gecontroleerd. Pseudomonas aeruginosa bleek

  7. Structural Insights on the bacteriolytic and self-protection mechanism of muramidase effector Tse3 in Pseudomonas aeruginosa.

    Science.gov (United States)

    Li, Lianbo; Zhang, Weili; Liu, Qisong; Gao, Yu; Gao, Ying; Wang, Yun; Wang, David Zhigang; Li, Zigang; Wang, Tao

    2013-10-18

    The warfare among microbial species as well as between pathogens and hosts is fierce, complicated, and continuous. In Pseudomonas aeruginosa, the muramidase effector Tse3 (Type VI secretion exported 3) can be injected into the periplasm of neighboring bacterial competitors by a Type VI secretion apparatus, eventually leading to cell lysis and death. However, P. aeruginosa protects itself from lysis by expressing immune protein Tsi3 (Type six secretion immunity 3). Here, we report the crystal structure of the Tse3-Tsi3 complex at 1.8 Å resolution, revealing that Tse3 possesses one open accessible, goose-type lysozyme-like domain with peptidoglycan hydrolysis activity. Calcium ions bind specifically in the Tse3 active site and are identified to be crucial for its bacteriolytic activity. In combination with biochemical studies, the structural basis of self-protection mechanism of Tsi3 is also elucidated, thus providing an understanding and new insights into the effectors of Type VI secretion system.

  8. Electrochemical reduction of oxygen catalyzed by Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Cournet, Amandine [Universite de Toulouse, UPS, LU49, Adhesion bacterienne et formation de biofilms, 35 chemin des Maraichers, 31062 Toulouse Cedex 09 (France)] [Laboratoire de Genie Chimique CNRS UMR5503, 4 allee Emile Monso, BP 84234, 31432 Toulouse Cedex 04 (France); Berge, Mathieu; Roques, Christine [Universite de Toulouse, UPS, LU49, Adhesion bacterienne et formation de biofilms, 35 chemin des Maraichers, 31062 Toulouse Cedex 09 (France); Bergel, Alain [Laboratoire de Genie Chimique CNRS UMR5503, 4 allee Emile Monso, BP 84234, 31432 Toulouse Cedex 04 (France); Delia, Marie-Line, E-mail: marieline.delia@ensiacet.f [Laboratoire de Genie Chimique CNRS UMR5503, 4 allee Emile Monso, BP 84234, 31432 Toulouse Cedex 04 (France)

    2010-07-01

    Pseudomonas aeruginosa has already been shown to catalyze oxidation processes in the anode compartment of a microbial fuel cell. The present study focuses on the reverse capacity of the bacterium, i.e. reduction catalysis. Here we show that P. aeruginosa is able to catalyze the electrochemical reduction of oxygen. The use of cyclic voltammetry showed that, for a given range of potential values, the current generated in the presence of bacteria could reach up to four times the current obtained without bacteria. The adhesion of bacteria to the working electrode was necessary for the catalysis to be observed but was not sufficient. The electron transfer between the working electrode and the bacteria did not involve mediator metabolites like phenazines. The transfer was by direct contact. The catalysis required a certain contact duration between electrodes and live bacteria but after this delay, the metabolic activity of cells was no longer necessary. Membrane-bound proteins, like catalase, may be involved. Various strains of P. aeruginosa, including clinical isolates, were tested and all of them, even catalase-defective mutants, presented the same catalytic property. P. aeruginosa offers a new model for the analysis of reduction catalysis and the protocol designed here may provide a basis for developing an interesting tool in the field of bacterial adhesion.

  9. Mass Spectrometry Analysis of Pseudomonas aeruginosa Treated with Azithromycin

    Science.gov (United States)

    Phelan, Vanessa V.; Fang, Jinshu; Dorrestein, Pieter C.

    2015-06-01

    In microbiology, changes in specialized metabolite production (cell-to-cell signaling metabolites, virulence factors, and natural products) are measured using phenotypic assays. However, advances in mass spectrometry-based techniques including imaging mass spectrometry (IMS) now allow researchers to directly visualize the production of specialized metabolites from microbial colony biofilms. In this study, a combination of IMS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to visualize the effect of the macrolide antibiotic azithromycin (AZM) on colony biofilms of Pseudomonas aeruginosa. Although previous research suggested that AZM may inhibit cell-to-cell signaling of P. aeruginosa and thereby reduce pathogenicity, we observed no clear decrease in specialized metabolite production.

  10. The implication of Pseudomonas aeruginosa biofilms in infections

    DEFF Research Database (Denmark)

    Rybtke, Morten T; Jensen, Peter Østrup; Høiby, Niels

    2011-01-01

    Biofilm formation by bacteria is recognized as a major problem in chronic infections due to their recalcitrance against the immune defense and available antibiotic treatment schemes. The opportunistic pathogen Pseudomonas aeruginosa has drawn special attention in this regard due to its severity......-up of the extracellular matrix encasing the biofilm-associated bacteria as well as the elaborate signaling mechanisms employed by the bacterium enables it to withstand the continuous stresses imposed by the immune defense and administered antibiotics resulting in a state of chronic inflammation that damages the host....... The immune response leading to this chronic inflammation is described. Finally, novel treatment strategies against P. aeruginosa are described including, quorum-sensing inhibition and induced biofilm-dispersion. The tolerance towards currently available antimicrobials calls for development of alternative...

  11. Attenuation of Pseudomonas aeruginosa virulence by quorum sensing inhibitors

    DEFF Research Database (Denmark)

    Hentzer, Morten; Wu, Hong; Andersen, Jens Bo

    2003-01-01

    Traditional treatment of infectious diseases is based on compounds that kill or inhibit growth of bacteria. A major concern with this approach is the frequent development of resistance to antibiotics. The discovery of communication systems (quorum sensing systems) regulating bacterial virulence has...... afforded a novel opportunity to control infectious bacteria without interfering with growth. Compounds that can override communication signals have been found in the marine environment. Using Pseudomonas aeruginosa PAO1 as an example of an opportunistic human pathogen, we show that a synthetic derivate...... and inhibited virulence factor expression. Application of the drug to P.aeruginosa biofilms increased bacterial susceptibility to tobramycin and SDS. In a mouse pulmonary infection model, the drug inhibited quorum sensing of the infecting bacteria and promoted their clearance by the mouse immune response....

  12. Flagellation of Pseudomonas aeruginosa in newly divided cells

    Science.gov (United States)

    Zhao, Kun; Lee, Calvin; Anda, Jaime; Wong, Gerard

    2015-03-01

    For monotrichous bacteria, Pseudomonas aeruginosa, after cell division, one daughter cell inherits the old flagellum from its mother cell, and the other grows a new flagellum during or after cell division. It had been shown that the new flagellum grows at the distal pole of the dividing cell when the two daughter cells haven't completely separated. However, for those daughter cells who grow new flagella after division, it still remains unknown at which pole the new flagellum will grow. Here, by combining our newly developed bacteria family tree tracking techniques with genetic manipulation method, we showed that for the daughter cell who did not inherit the old flagellum, a new flagellum has about 90% chances to grow at the newly formed pole. We proposed a model for flagellation of P. aeruginosa.

  13. Pyocyanin degradation by a tautomerizing demethylase inhibits Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Costa, Kyle C; Glasser, Nathaniel R; Conway, Stuart J; Newman, Dianne K

    2017-01-13

    The opportunistic pathogen Pseudomonas aeruginosa produces colorful redox-active metabolites called phenazines, which underpin biofilm development, virulence, and clinical outcomes. Although phenazines exist in many forms, the best studied is pyocyanin. Here, we describe pyocyanin demethylase (PodA), a hitherto uncharacterized protein that oxidizes the pyocyanin methyl group to formaldehyde and reduces the pyrazine ring via an unusual tautomerizing demethylation reaction. Treatment with PodA disrupts P. aeruginosa biofilm formation similarly to DNase, suggesting interference with the pyocyanin-dependent release of extracellular DNA into the matrix. PodA-dependent pyocyanin demethylation also restricts established biofilm aggregate populations experiencing anoxic conditions. Together, these results show that modulating extracellular redox-active metabolites can influence the fitness of a biofilm-forming microorganism. Copyright © 2017, American Association for the Advancement of Science.

  14. The implication of Pseudomonas aeruginosa biofilms in infections

    DEFF Research Database (Denmark)

    Rybtke, Morten Theil; Jensen, Peter Ø; Høiby, Niels

    2011-01-01

    . The immune response leading to this chronic inflammation is described. Finally, novel treatment strategies against P. aeruginosa are described including, quorum-sensing inhibition and induced biofilm-dispersion. The tolerance towards currently available antimicrobials calls for development of alternative......Biofilm formation by bacteria is recognized as a major problem in chronic infections due to their recalcitrance against the immune defense and available antibiotic treatment schemes. The opportunistic pathogen Pseudomonas aeruginosa has drawn special attention in this regard due to its severity......-up of the extracellular matrix encasing the biofilm-associated bacteria as well as the elaborate signaling mechanisms employed by the bacterium enables it to withstand the continuous stresses imposed by the immune defense and administered antibiotics resulting in a state of chronic inflammation that damages the host...

  15. Hemorrhagic pneumonia in mink caused by Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Salomonsen, Charlotte Mark

    experiencing outbreaks of hemorrhagic pneumonia among their mink was that the disease always started in the mink kits, never in the adults. Furthermore, 39% reported that most deaths occurred in the male mink. The results presented in this thesis suggest that factors of the mink make them more prone to develop......Hemorrhagic pneumonia in mink is an acute and fatal disease caused by Pseudomonas aeruginosa. The mink are typically found dead without prior clinical symptoms. The disease can be highly contagious and varying mortalities on the farm level has been reported. Hemorrhagic pneumonia in mink...... is seasonal with outbreaks almost exclusively occurring from September to November in Denmark. In human medicine, P. aeruginosa is regarded as a pathogen for immune compromised individuals but no underlying disease or immune defect has been identified in mink dying of hemorrhagic pneumonia. In fact, little...

  16. Evolution and Pathoadaptation of Pseudomonas aeruginosa in Cystic Fibrosis Patients

    DEFF Research Database (Denmark)

    Marvig, Rasmus Lykke

    understanding of how bacteria evolve and genetically adapt in a natural environment. In particular we sought to identify the genes that are targeted by mutation to optimize fitness in a given environment, and to understand the evolutionary mechanisms that govern the genetic change. Pseudomonas aeruginosa...... is the dominating pathogen of chronic airway infections in patients with cystic fibrosis (CF), and the bacterial long-term persistence in CF hosts involves mutation and selection of genetic variants with increased fitness in the CF airways. We performed a retrospective study of the P. aeruginosa DK2 clone type......, which is a transmissible clone isolated from chronically infected Danish CF patients over a period of 38 years. Whole-genome analysis of DK2 isolates enabled a finegrained reconstruction of the recent evolutionary history of the DK2 lineage and an identification of bacterial genes targeted by mutations...

  17. Plasmid profile as fingerprinting of typing Pseudomonas aeruginosa

    OpenAIRE

    El-Naggar, Wael; El-Emam, M; Hassan, R; George, S

    2014-01-01

    Pyocine production typing and restriction fragment length polymorphism (RFLP) of plasmid DNA with BamH1 (BamH1 RFLP) were compared for intraspecies discrimination of 100 Pseudomonas aeruginosa isolates. Typeability of pyocine production method was 76% while that of BamH1 RFLP was 100%. BamHl RFLP was highly discriminative so as to distinguish unrelated isolates of close lineage. However, it was not a good method to identify isolates of unrelated lineage because BamH1 RFLP appeared to be a sub...

  18. Vaccines for Pseudomonas aeruginosa: A long and winding road

    Science.gov (United States)

    Priebe, Gregory P.; Goldberg, Joanna B.

    2015-01-01

    Summary Despite the recognition of Pseudomonas aeruginosa is an opportunistic pathogen, no vaccine against this bacteria have come to market. This review describes the current state-of-the-art in vaccinology for this bacterium. This includes a discussion of those at risk for infection, the types of vaccines and the approaches for empirical and targeted antigen selection under development, as well as a perspective on where the field should go. In addition, the challenges in developing a vaccine for those individuals at risk are discussed. PMID:24575895

  19. An unusual presentation of Pseudomonas aeruginosa blebitis following combined surgery

    Directory of Open Access Journals (Sweden)

    Shabana Bharathi

    2014-01-01

    Full Text Available We report a case of blebitis that occurred 3 years later following a combined glaucoma and cataract surgery. It was an atypical presentation, as patient had no classical fiery looking signs of blebitis despite the isolated organism being Pseudomonas aeruginosa. Improvized surgical techniques like use of Mitomycin C, releasable flap sutures though considered as part of the recommended procedure for better surgical outcomes, their role as potential risk factors for visually blinding complications like endophthalmitis are often overlooked. This case report throws light on such risk factors for bleb associated infections and recommends removal or trimming of all releasable sutures and the need for a regular postoperative follow-up.

  20. In vivo and In vitro Interactions between Pseudomonas aeruginosa and Staphylococcus spp.

    Science.gov (United States)

    Hotterbeekx, An; Kumar-Singh, Samir; Goossens, Herman; Malhotra-Kumar, Surbhi

    2017-01-01

    The significance of polymicrobial infections is increasingly being recognized especially in a biofilm context wherein multiple bacterial species—including both potential pathogens and members of the commensal flora—communicate, cooperate, and compete with each other. Two important bacterial pathogens that have developed a complex network of evasion, counter-inhibition, and subjugation in their battle for space and nutrients are Pseudomonas aeruginosa and Staphylococcus aureus. Their strain- and environment-specific interactions, for instance in the cystic fibrosis lung or in wound infections, show severe competition that is generally linked to worse patient outcomes. For instance, the extracellular factors secreted by P. aeruginosa have been shown to subjugate S. aureus to persist as small colony variants (SCVs). On the other hand, data also exist where S. aureus inhibits biofilm formation by P. aeruginosa but also protects the pathogen by inhibiting its phagocytosis. Interestingly, such interspecies interactions differ between the planktonic and biofilm phenotype, with the extracellular matrix components of the latter likely being a key, and largely underexplored, influence. This review attempts to understand the complex relationship between P. aeruginosa and Staphylococcus spp., focusing on S. aureus, that not only is interesting from the bacterial evolution point of view, but also has important consequences for our understanding of the disease pathogenesis for better patient management. PMID:28421166

  1. Genotypic and phenotypic characterization of Pseudomonas aeruginosa isolates from post-cataract endophthalmitis patients.

    Science.gov (United States)

    Lakshmi Priya, Jeganathan; Prajna, Lalitha; Mohankumar, Vidyarani

    2015-01-01

    Endophthalmitis caused by Pseudomonas aeruginosa is associated with rapid disease progression and poor visual outcome due to high virulence of the organism. Our aim was to characterize the virulence determinants of P. aeruginosa causing post-operative endophthalmitis. Repetitive sequence analysis (ERIC PCR) was done to study the clonal relatedness of the 17 P. aeruginosa isolates. Type 3 secretion system (T3SS) genotypes were determined and the isolates were further classified as invasive or cytotoxic based on gentamicin survival, trypan blue dye exclusion and MTT assays. Phenotypically, the strains were characterized based on bacterial motility patterns, biofilm formation, phospholipase production and antibiotic susceptibility patterns. Most of our ocular isolates were invasive in nature and nearly half of them were multi-drug resistant. 47% of the isolates formed a strong biofilm, whereas the rest formed moderate to weak biofilms, which may account for an increased colonization and antibiotic resistance. Although the T3SS genotypes correlated well with the invasive/cytotoxic nature of the strains, none of the genotypes were associated with any particular phenotypic trait. To the best of our knowledge, this is the first report on the phenotypic characteristics of P. aeruginosa strains causing post-operative endophthalmitis. Our findings demonstrate that these strains have higher invasive potential and an ability to form biofilm which possibly contributes to an increased ocular virulence. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. The Heterologous Siderophores Ferrioxamine B and Ferrichrome Activate Signaling Pathways in Pseudomonas aeruginosa

    Science.gov (United States)

    Llamas, María A.; Sparrius, Marion; Kloet, Roy; Jiménez, Connie R.; Vandenbroucke-Grauls, Christina; Bitter, Wilbert

    2006-01-01

    Pseudomonas aeruginosa secretes two siderophores, pyoverdine and pyochelin, under iron-limiting conditions. These siderophores are recognized at the cell surface by specific outer membrane receptors, also known as TonB-dependent receptors. In addition, this bacterium is also able to incorporate many heterologous siderophores of bacterial or fungal origin, which is reflected by the presence of 32 additional genes encoding putative TonB-dependent receptors. In this work, we have used a proteomic approach to identify the inducing conditions for P. aeruginosa TonB-dependent receptors. In total, 11 of these receptors could be discerned under various conditions. Two of them are only produced in the presence of the hydroxamate siderophores ferrioxamine B and ferrichrome. Regulation of their synthesis is affected by both iron and the presence of a cognate siderophore. Analysis of the P. aeruginosa genome showed that both receptor genes are located next to a regulatory locus encoding an extracytoplasmic function sigma factor and a transmembrane sensor. The involvement of this putative regulatory locus in the specific induction of the ferrioxamine B and ferrichrome receptors has been demonstrated. These results show that P. aeruginosa has evolved multiple specific regulatory systems to allow the regulation of TonB-dependent receptors. PMID:16484199

  3. Pseudomonas aeruginosa vesicles associate with and are internalized by human lung epithelial cells

    Directory of Open Access Journals (Sweden)

    Kuehn Meta J

    2009-02-01

    Full Text Available Abstract Background Pseudomonas aeruginosa is the major pathogen associated with chronic and ultimately fatal lung infections in patients with cystic fibrosis (CF. To investigate how P. aeruginosa-derived vesicles may contribute to lung disease, we explored their ability to associate with human lung cells. Results Purified vesicles associated with lung cells and were internalized in a time- and dose-dependent manner. Vesicles from a CF isolate exhibited a 3- to 4-fold greater association with lung cells than vesicles from the lab strain PAO1. Vesicle internalization was temperature-dependent and was inhibited by hypertonic sucrose and cyclodextrins. Surface-bound vesicles rarely colocalized with clathrin. Internalized vesicles colocalized with the endoplasmic reticulum (ER marker, TRAPα, as well as with ER-localized pools of cholera toxin and transferrin. CF isolates of P. aeruginosa abundantly secrete PaAP (PA2939, an aminopeptidase that associates with the surface of vesicles. Vesicles from a PaAP knockout strain exhibited a 40% decrease in cell association. Likewise, vesicles from PAO1 overexpressing PaAP displayed a significant increase in cell association. Conclusion These data reveal that PaAP promotes the association of vesicles with lung cells. Taken together, these results suggest that P. aeruginosa vesicles can interact with and be internalized by lung epithelial cells and contribute to the inflammatory response during infection.

  4. Loss of social behaviours in populations of Pseudomonas aeruginosa infecting lungs of patients with cystic fibrosis.

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    Natalie Jiricny

    Full Text Available Pseudomonas aeruginosa, is an opportunistic, bacterial pathogen causing persistent and frequently fatal infections of the lung in patients with cystic fibrosis. Isolates from chronic infections differ from laboratory and environmental strains in a range of traits and this is widely interpreted as the result of adaptation to the lung environment. Typically, chronic strains carry mutations in global regulation factors that could effect reduced expression of social traits, raising the possibility that competitive dynamics between cooperative and selfish, cheating strains could also drive changes in P. aeruginosa infections. We compared the expression of cooperative traits - biofilm formation, secretion of exo-products and quorum sensing (QS - in P. aeruginosa isolates that were estimated to have spent different lengths of time in the lung based on clinical information. All three exo-products involved in nutrient acquisition were produced in significantly smaller quantities with increased duration of infection, and patterns across four QS signal molecules were consistent with accumulation over time of mutations in lasR, which are known to disrupt the ability of cells to respond to QS signal. Pyocyanin production, and the proportion of cells in biofilm relative to motile, free-living cells in liquid culture, did not change. Overall, our results confirm that the loss of social behaviour is a consistent trend with time spent in the lung and suggest that social dynamics are potentially relevant to understanding the behaviour of P. aeruginosa in lung infections.

  5. Identification of essential genes of Pseudomonas aeruginosa for its growth in airway mucus.

    Science.gov (United States)

    Alrahman, Mohammed Abd; Yoon, Sang Sun

    2017-01-01

    Pseudomonas aeruginosa has been identified as an important causative agent of airway infection, mainly in cystic fibrosis. This disease is characterized by defective mucociliary clearance induced in part by mucus hyper-production. Mucin is a major component of airway mucus and is heavily O-glycosylated, with a protein backbone. Airway infection is known to be established with bacterial adhesion to mucin. However, the genes involved in mucin degradation or utilization remain elusive. In this study, we sought to provide a genetic basis of P. aeruginosa airway growth by identifying those genes. First, using RNASeq analyses, we compared genome-wide expression profiles of PAO1, a prototype P. aeruginosa laboratory strain, grown in M9-mucin (M9M) and M9-glucose (M9G) media. Additionally, a PAO1 transposon (Tn) insertion mutants library was screened for mutants defective in growth in M9M medium. One mutant with a Tn insertion in the xcpU gene (PA3100) was determined to exhibit faulty growth in M9M medium. This gene contributes to the type II secretion system, suggesting that P. aeruginosa uses this secretion system to produce a number of proteins to break down and assimilate the mucin molecule. Furthermore, we screened the PAO1 genome for genes with protease activity. Of 13 mutants, one with mutation in PA3247 gene exhibited defective growth in M9M, suggesting that the PA3247-encoded protease plays a role in mucin utilization. Further mechanistic dissection of this particular process will reveal new drug targets, the inhibition of which could control recalcitrant P. aeruginosa infections.

  6. Role of mutation in Pseudomonas aeruginosa biofilm development.

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    Tim C R Conibear

    2009-07-01

    Full Text Available The survival of bacteria in nature is greatly enhanced by their ability to grow within surface-associated communities called biofilms. Commonly, biofilms generate proliferations of bacterial cells, called microcolonies, which are highly recalcitrant, 3-dimensional foci of bacterial growth. Microcolony growth is initiated by only a subpopulation of bacteria within biofilms, but processes responsible for this differentiation remain poorly understood. Under conditions of crowding and intense competition between bacteria within biofilms, microevolutionary processes such as mutation selection may be important for growth; however their influence on microcolony-based biofilm growth and architecture have not previously been explored. To study mutation in-situ within biofilms, we transformed Pseudomonas aeruginosa cells with a green fluorescent protein gene containing a +1 frameshift mutation. Transformed P. aeruginosa cells were non-fluorescent until a mutation causing reversion to the wildtype sequence occurs. Fluorescence-inducing mutations were observed in microcolony structures, but not in other biofilm cells, or in planktonic cultures of P. aeruginosa cells. Thus microcolonies may represent important foci for mutation and evolution within biofilms. We calculated that microcolony-specific increases in mutation frequency were at least 100-fold compared with planktonically grown cultures. We also observed that mutator phenotypes can enhance microcolony-based growth of P. aeruginosa cells. For P. aeruginosa strains defective in DNA fidelity and error repair, we found that microcolony initiation and growth was enhanced with increased mutation frequency of the organism. We suggest that microcolony-based growth can involve mutation and subsequent selection of mutants better adapted to grow on surfaces within crowded-cell environments. This model for biofilm growth is analogous to mutation selection that occurs during neoplastic progression and tumor

  7. One-step purification and characterization of alginate lyase from a clinical Pseudomonas aeruginosa with destructive activity on bacterial biofilm.

    Science.gov (United States)

    Ghadam, Parinaz; Akhlaghi, Fatemeh; Ali, Ahya Abdi

    2017-05-01

    Pseudomonas aeruginosa is a Gram-negative and aerobic rod bacterium that displays mucoid and non-mucoid phenotype. Mucoid strains secrete alginate, which is the main agent of biofilms in chronic P. aeruginosa infections, show high resistance to antibiotics; consequently, the biological disruption of mucoid P. aeruginosa biofilms is an attractive area of study for researchers. Alginate lyase gene (algl) is a member of alginate producing operon which by glycosidase activity produces primer for other enzymes in this cluster. Also this activity can destroy the extracellular alginate; therefore this enzyme participates in alginate production and destruction pathway. Alginate lyase causes detachment of a biofilm by reducing its adhesion to the surfaces, and increases phagocytosis and antibiotic susceptibility. In this study, alginate lyase was purified in just one step and its properties were investigated. The purification was done by affinity chromatography, analysed by SDS-PAGE, and its effect on P. aeruginosa biofilms was surveyed by micro titer plate assay and SEM. The substrate specificity of the enzyme was determined by PCR. Alginate lyase from isolate 48 was purified in one step. It is more thermally resistant than alginate lyase from Pseudomonas aeruginosa PAO1 and poly M, poly G and poly MG alginate were the substrate of this enzyme. Moreover, it has an eradication effect on biofilms from P. aeruginosa 48 and PAO1. In this study an alginate lyase with many characteristics suitable in medicine such as thermal stability, effective on poly M alginate, and bacterial biofilm destructive was introduced and purified.

  8. Role of quorum sensing by Pseudomonas aeruginosa in microbial keratitis and cystic fibrosis

    DEFF Research Database (Denmark)

    Willcox, M.D.P.; Zhu, H.; Conibear, T.C.R.

    2008-01-01

    Pseudomonas aeruginosa is a ubiquitous bacterium that causes opportunistic infections in a range of host tissues and organs. Infections by P. aeruginosa are difficult to treat and hence there is interest in the development of effective therapeutics. One of the key mechanisms that P. aeruginosa uses...

  9. Evaluation of a FRET-peptide substrate to predict virulence in Pseudomonas aeruginosa

    NARCIS (Netherlands)

    W.E. Kaman (Wendy); N. El Arkoubi-El Arkoubi (Nora); S. Roffel (Sanne); H.P. Endtz (Hubert); A.F. van Belkum (Alex); F.J. Bikker (Floris); J.P. Hays (John)

    2013-01-01

    textabstractPseudomonas aeruginosa produces a number of proteases that are associated with virulence and disease progression. A substrate able to detect P. aeruginosa-specific proteolytic activity could help to rapidly alert clinicians to the virulence potential of individual P. aeruginosa strains.

  10. Evaluation of a FRET-peptide substrate to predict virulence in Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Kaman, W.E.; El Arkoubi-El Arkoubi, N.; Roffel, S.; Endtz, H.P.; van Belkum, A.; Bikker, F.J.; Hays, J.P.

    2013-01-01

    Pseudomonas aeruginosa produces a number of proteases that are associated with virulence and disease progression. A substrate able to detect P. aeruginosa-specific proteolytic activity could help to rapidly alert clinicians to the virulence potential of individual P. aeruginosa strains. For this

  11. A case of failed eradication of cystic fibrosis-related sinus colonisation by Pseudomonas aeruginosa.

    LENUS (Irish Health Repository)

    Linnane, Barry

    2015-10-01

    Pseudomonas aeruginosa is a pathogen associated with cystic fibrosis that has potential to decrease lung function and cause respiratory failure. Paranasal sinuses are increasingly recognised as potential reservoirs for intermittent colonisation by P. aeruginosa. This case documents investigation and outcome of P. aeruginosa recurrence in a male paediatric patient over an eight year period.

  12. Rapid detection of Pseudomonas aeruginosa biomarkers in biological fluids using surface-enhanced Raman scattering

    Science.gov (United States)

    Wu, Xiaomeng; Chen, Jing; Zhao, Yiping; Zughaier, Susu M.

    2014-05-01

    Pseudomonas aeruginosa (PA) is an opportunistic pathogen that causes major infection not only in Cystic Fibrosis patients but also in chronic obstructive pulmonary disease and in critically ill patients in intensive care units. Successful antibiotic treatment of the infection relies on accurate and rapid identification of the infectious agents. Conventional microbiological detection methods usually take more than 3 days to obtain accurate results. We have developed a rapid diagnostic technique based on surface-enhanced Raman scattering to directly identify PA from biological fluids. P. aeruginosa strains, PAO1 and PA14, are cultured in lysogeny broth, and the SERS spectra of the broth show the signature Raman peaks from pyocyanin and pyoverdine, two major biomarkers that P. aeruginosa secretes during its growth, as well as lipopolysaccharides. This provides the evidence that the presence of these biomarkers can be used to indicate P. aeruginosa infection. A total of 22 clinical exhaled breath condensates (EBC) samples were obtained from subjects with CF disease and from non-CF healthy donors. SERS spectra of these EBC samples were obtained and further analyzed by both principle component analysis and partial least square-discriminant analysis (PLS-DA). PLS-DA can discriminate the samples with P. aeruginosa infection and the ones without P. aeruginosa infection at 99.3% sensitivity and 99.6% specificity. In addition, this technique can also discriminate samples from subject with CF disease and healthy donor with 97.5% sensitivity and 100% specificity. These results demonstrate the potential of using SERS of EBC samples as a rapid diagnostic tool to detect PA infection.

  13. Flow environment and matrix structure interact to determine spatial competition in Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Nadell, Carey D; Ricaurte, Deirdre; Yan, Jing; Drescher, Knut; Bassler, Bonnie L

    2017-01-13

    Bacteria often live in biofilms, which are microbial communities surrounded by a secreted extracellular matrix. Here, we demonstrate that hydrodynamic flow and matrix organization interact to shape competitive dynamics in Pseudomonas aeruginosa biofilms. Irrespective of initial frequency, in competition with matrix mutants, wild-type cells always increase in relative abundance in planar microfluidic devices under simple flow regimes. By contrast, in microenvironments with complex, irregular flow profiles - which are common in natural environments - wild-type matrix-producing and isogenic non-producing strains can coexist. This result stems from local obstruction of flow by wild-type matrix producers, which generates regions of near-zero shear that allow matrix mutants to locally accumulate. Our findings connect the evolutionary stability of matrix production with the hydrodynamics and spatial structure of the surrounding environment, providing a potential explanation for the variation in biofilm matrix secretion observed among bacteria in natural environments.

  14. Biodegradasi Petroleum dan Hidrokarbon Eikosana oleh Isolat Bakteri Pseudomonas aeruginosa

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    Faiqah Umar

    2015-01-01

    Full Text Available Biodegradation of petroleum and hydrocarbon eicosane by Pseudomonas aeruginosa isolate. Hydrocarbon are important environmental contaminants in soil and water. These compounds have a potential risk to human health, as many of them are carsinogenic and toxic to marine organisms such as diatome, gasthrophode, mussel, and fish. The purpose of this research was to know the ability of Pseudomonas aeruginosa to degradate the hydrocarbon (petroleum Hundill and eicosane substrate. Growing test used in two steps, the preculture and culture step. The biodegradation capacity was measured by quantitative and qualitative tests. The essay showed an increasing biodegradation capacitypercentage of bacteria cell mass on hydrocarbon substrate. The percentage on petroleum Hundill substrat as follows; log phase was 51,6%, descelerate phase was 73%, and linear phase was 81,4%. On eicosane substrate as follows; log phase was 62,7%, descelerate phase was 85,2%, and linear phase was 85,2%. The qualitative biodegradation capacity by chromatography result showed separate enchained of carbon n-alkana in each growth phase on petroleum Hundill substrate. Carbon chain termination as follows; C11, C12, C14, C15, C16, C18, C22 on log phase, C12, C17, C19, C20, C24 on descelerate phase, and C12 until C25 even better on linear phase.

  15. PARTIAL PURIFICATION AND CHARACTERIZATION OF ALKALOPHILIC PROTEASE FROM PSEUDOMONAS AERUGINOSA

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    R. Satheeskumar

    2013-10-01

    Full Text Available Partial purification and characterization of alkalophilic protease production from Pseudomonas aeruginosa was isolated from the gut of marine and coastal waters shrimp Penaeus monodon. The protease production was assayed in submerged fermentation to produce maximum protease activity (423 ± 0.09 U/ml. The enzyme was precipitated with ammonium sulphate and partially purified by ion exchange chromatography through DEAE Sephadex A-50 column. In 10th fraction showed maximum protease activity (734 ± 0.18 U/ml with increase in purification fold. The molecular weight of protease from Pseudomonas aeruginosa was recorded as 60 kDa. The stability of protease was tested at various pH and temperature; it showed maximum protease activity at pH-9 and temperature 50ºC. Among the various surfactants tested for enzyme stability, maximum activity was retained in poly ethylene glycol. The compatibility of protease enzyme with various commercial detergents; the enzyme retained maximum protease activity in tide. The results are indicated that all these properties make the bacterial proteases are most suitable for wide industrial applications.

  16. PA3297 Counteracts Antimicrobial Effects of Azithromycin in Pseudomonas aeruginosa

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    Hao eTan

    2016-03-01

    Full Text Available Pseudomonas aeruginosa causes acute and chronic infections in human. Its increasing resistance to antibiotics requires alternative treatments that are more effective than available strategies. Among the alternatives is the unconventional usage of conventional antibiotics, of which the macrolide antibiotic azithromycin (AZM provides a paradigmatic example. AZM therapy is associated with a small but consistent improvement in respiratory function of cystic fibrosis (CF patients suffering from chronic P. aeruginosa infection. Besides immunomodulating activities, AZM represses bacterial genes involved in virulence, quorum sensing, biofilm formation, and motility, all of which are due to stalling of ribosome and depletion of cellular tRNA pool. However, how P. aeruginosa responds to and counteracts the effects of AZM remain elusive. Here we found that deficiency of PA3297, a gene encoding a DEAH-box helicase, intensified AZM-mediated bacterial killing, suppression of pyocyanin production and swarming motility, and hypersusceptibility to hydrogen peroxide. We demonstrated that expression of PA3297 is induced by the interaction between AZM and ribosome. Importantly, mutation of PA3297 resulted in elevated levels of unprocessed 23S-5S rRNA in the presence of AZM, which might lead to increased susceptibility to AZM-mediated effects. Our results revealed one of the bacterial responses in counteracting the detrimental effects of AZM.

  17. Characterization of environmental Pseudomonas aeruginosa using multilocus sequence typing scheme.

    Science.gov (United States)

    Radó, Júlia; Kaszab, Edit; Petrovics, Tünde; Pászti, Judit; Kriszt, Balázs; Szoboszlay, Sándor

    2017-10-01

    The objectives of this study were to examine environmental (hydrocarbon degrading) Pseudomonas aeruginosa isolates with Multilocus Sequence Typing (MLST) and to determine their relevant features, such as serotype, virulence genes, biofilm forming ability and hydrocarbon degrading capacity. The diversity of environmental isolates was assessed with an MLST scheme. Investigation of virulence determinants included serotyping, hemolytic activity test and the detection of virulence genes exoS, exoY, exoT, exoU, exoA. Biofilm forming ability was examined in a modified microtiter assay, hydrocarbon degrading capacity was determined with gravimetric methods. The majority of environmental isolates shared the same MLST profiles with isolates of cystic fibrosis (CF). Virulence patterns and serotypes were slightly connected to the phylogenetic localization, but further clinically important features such as antibiotic resistance were not. At least one of the examined environmental isolates was multidrug-resistant, virulent and had biofilm forming ability such as nosocomial P. aeruginosa and retained its hydrocarbon degradation ability. The current theses that distinguish isolates originating from different sources are questionable; environmental P. aeruginosa can be a potential risk to public health and cannot be excluded as an external (non-nosocomial) source of infections, especially in patients with CF. Further studies such as pulsed-field gel electrophoresis (PFGE) and the determination of other clinically important virulence factors are needed to confirm these findings.

  18. Plant-expressed pyocins for control of Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Šarūnas Paškevičius

    Full Text Available The emergence, persistence and spread of antibiotic-resistant human pathogenic bacteria heralds a growing global health crisis. Drug-resistant strains of gram-negative bacteria, such as Pseudomonas aeruginosa, are especially dangerous and the medical and economic burden they impose underscore the critical need for finding new antimicrobials. Recent studies have demonstrated that plant-expressed bacteriocins of the colicins family can be efficient antibacterials against all major enteropathogenic strains of E. coli. We extended our studies of colicin-like bacteriocins to pyocins, which are produced by strains of P. aeruginosa for ecological advantage against other strains of the same species. Using a plant-based transient expression system, we expressed six different pyocins, namely S5, PaeM, L1, L2, L3 and one new pyocin, PaeM4, and purified them to homogeneity. Among these pyocins, PaeM4 demonstrated the broadest spectrum of activity by controlling 53 of 100 tested clinical isolates of P. aeruginosa. The activity of plant-made pyocins was confirmed in the agar drop, liquid culture susceptibility and biofilm assays, and in the Galleria mellonella animal infection model.

  19. Selection of DNA aptamers specific for live Pseudomonas aeruginosa.

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    Jennifer Soundy

    Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen that causes significant morbidity and mortality in immunocompromised patients, particular cystic fibrosis sufferers, burns victims, diabetics and neonates. It thrives in moist places where it forms biofilms that are exceedingly difficult to eradicate on hospital surfaces, in water supplies and implanted biomaterials. Using a live cell SELEX approach we selected DNA aptamers to P. aeruginosa grown as biofilms in microfluidic cells. From a pool of aptamer candidates showing tight binding a stem-loop structure was identified as being important for binding. Enhanced binding and increased specificity was achieved by truncating structures and generating chimeric aptamers from the pool of top candidates. The top candidates have low nanomolar binding constants and high discrimination for P. aeruginosa over other Gram-negative bacteria. The aptamers bind both planktonic grown and biofilm grown cells. They do not have intrinsic bacteriostatic or bactericidal activity, but are ideal candidates for modification for use as aptamer-drug conjugates and in biosensors.

  20. Gallium induces the production of virulence factors in Pseudomonas aeruginosa.

    Science.gov (United States)

    García-Contreras, Rodolfo; Pérez-Eretza, Berenice; Lira-Silva, Elizabeth; Jasso-Chávez, Ricardo; Coria-Jiménez, Rafael; Rangel-Vega, Adrián; Maeda, Toshinari; Wood, Thomas K

    2014-02-01

    The novel antimicrobial gallium is a nonredox iron III analogue with bacteriostatic and bactericidal properties, effective for the treatment of Pseudomonas aeruginosa in vitro and in vivo in mouse and rabbit infection models. It interferes with iron metabolism, transport, and presumably its homeostasis. As gallium exerts its antimicrobial effects by competing with iron, we hypothesized that it ultimately will lead cells to an iron deficiency status. As iron deficiency promotes the expression of virulence factors in vitro and promotes the pathogenicity of P. aeruginosa in animal models, it is anticipated that treatment with gallium will also promote the production of virulence factors. To test this hypothesis, the reference strain PA14 and two clinical isolates from patients with cystic fibrosis were exposed to gallium, and their production of pyocyanin, rhamnolipids, elastase, alkaline protease, alginate, pyoverdine, and biofilm was determined. Gallium treatment induced the production of all the virulence factors tested in the three strains except for pyoverdine. In addition, as the Ga-induced virulence factors are quorum sensing controlled, co-administration of Ga and the quorum quencher brominated furanone C-30 was assayed, and it was found that C-30 alleviated growth inhibition from gallium. Hence, adding both C-30 and gallium may be more effective in the treatment of P. aeruginosa infections. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  1. Characterization of Pseudomonas aeruginosa with discrepant carbapenem susceptibility profile.

    Science.gov (United States)

    Pragasam, Agila K; Raghanivedha, M; Anandan, Shalini; Veeraraghavan, Balaji

    2016-02-24

    Pseudomonas aeruginosa is the most common nosocomial pathogen, notorious for its multidrug resistance and causes life threatening infections. Carbapenems were considered as the last resort of drugs for the treatment of multi drug resistant P. aeruginosa infections. The emergence of resistance to carbapenems limits its use for treatment. Unlike other organisms, in P. aeruginosa intrinsic/chromosomal mediated resistance mechanisms plays a major role for carbapenem resistance rather than the carbapenemases. Carbapenemase producing organisms becomes resistant to both imipenem and meropenem. However, in our clinical settings, we have observed rare carbapenem resistant phenotypes such as imipenem resistant but meropenem susceptible (IRMS) and meropenem resistant but imipenem susceptible (MRIS) phenotypes. Thus we have chosen these rare phenotypes to look for the respective resistance mechanisms by phenotypic and molecular methods. From this study we found that, IRMS is primarily due to the mutations across various regions in the loops of oprD gene and MRIS is due to the over expression of mexAB efflux pumps. This study results confirms that, this rare phenotypes are due to the intrinsic/chromosomal mediated mechanisms, which occurred due to the antibiotic selection pressure. This study also provided data concerning alterations in outer membrane permeability which is often associated with the increased levels of antibiotic efflux. Consequently, this study provided the prevalence of the various resistance mechanisms that have deployed by the organism to resist antibiotics through different phenotypes.

  2. In vitro antimicrobial activity of LED irradiation on Pseudomonas aeruginosa.

    Science.gov (United States)

    Petrini, Morena; Trentini, Paolo; Tripodi, Domenico; Spoto, Giuseppe; D'Ercole, Simonetta

    2017-03-01

    Pseudomonas aeruginosa is an opportunistic pathogen responsible of many deaths due to nosocomial pneumonia each year. It is particularly resistant to many different classes of antibiotics and disinfectants. For all these reasons, there is the necessity to find novel approaches of treatment. The aim of this study was to evaluate the effect of 880nm light emitting diodes (LED) irradiation on P. aeruginosa, in vitro. Different LED irradiation parameters (time, energy output and the addition of methylene blue and chlorhexidine) have been tested in order to evaluate the effects on this bacterium. After treatment, the colony forming units per milliliter (CFU mL-1) were recorded and the data were submitted to ANOVA and Bonferroni post hoc tests at a level of significance of 5%. A statistical significant reduction of bacterial count has been registered after 5min of LED irradiation. The antibacterial effect was directly proportional to irradiation time and the output energy. The pre-treatment with methylene blue, seems to be not effective against P. aeruginosa, independently from irradiation parameters. On the contrary, the contemporary action of LED and chlorhexidine has shown a great reduction of bacterial count that was statistical significant respect chlorhexidine and LED alone. The effect of LED irradiation was visible also after 24h, when a lower bacterial count characterized all irradiated samples respect controls. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Inactivation of the potent Pseudomonas aeruginosa cytotoxin pyocyanin by airway peroxidases and nitrite.

    Science.gov (United States)

    Reszka, Krzysztof J; Xiong, Ye; Sallans, Larry; Pasula, Rajamouli; Olakanmi, Oyebode; Hassett, Daniel J; Britigan, Bradley E

    2012-05-15

    Pyocyanin (1-hydroxy-N-methylphenazine, PCN) is a cytotoxic pigment and virulence factor secreted by the human bacterial pathogen, Pseudomonas aeruginosa. Here, we report that exposure of PCN to airway peroxidases, hydrogen peroxide (H(2)O(2)), and NaNO(2) generates unique mononitrated PCN metabolites (N-PCN) as revealed by HPLC/mass spectrometry analyses. N-PCN, in contrast to PCN, was devoid of antibiotic activity and failed to kill Escherichia coli and Staphylococcus aureus. Furthermore, in contrast to PCN, intratracheal instillation of N-PCN into murine lungs failed to induce a significant inflammatory response. Surprisingly, at a pH of ∼7, N-PCN was more reactive than PCN with respect to NADH oxidation but resulted in a similar magnitude of superoxide production as detected by electron paramagnetic resonance and spin trapping experiments. When incubated with Escherichia coli or lung A549 cells, PCN and N-PCN both led to superoxide formation, but lesser amounts were detected with N-PCN. Our results demonstrate that PCN that has been nitrated by peroxidase/H(2)O(2)/NO(2)(-) systems possesses less cytotoxic/proinflammatory activity than native PCN. Yield of N-PCN was decreased by the presence of the competing physiological peroxidase substrates (thiocyonate) SCN(-) (myeloperoxidase, MPO, and lactoperoxidase, LPO) and Cl(-) (MPO), which with Cl(-) yielded chlorinated PCNs. These reaction products also showed decreased proinflammatory ability when instilled into the lungs of mice. These observations add important insights into the complexity of the pathogenesis of lung injury associated with Pseudomonas aeruginosa infections and provide additional rationale for exploring the efficacy of NO(2)(-) in the therapy of chronic Pseudomonas aeruginosa airway infection in cystic fibrosis.

  4. Spontaneous Nosocomial Pseudomonas aeruginosa Meningitis Presenting as Trismus

    Directory of Open Access Journals (Sweden)

    C. J. Parr

    2017-01-01

    Full Text Available We describe the case of a 78-year-old female receiving adjuvant postsurgical chemotherapy for colon adenocarcinoma who spontaneously developed nosocomial Pseudomonas meningitis causing severe trismus. The patient was initially admitted for ileus, developing neck stiffness and trismus on the thirteenth day of admission. Cerebrospinal fluid grew pansensitive Pseudomonas aeruginosa. Magnetic resonance imaging of the brain was consistent with bilateral subacute infarcts secondary to meningitis. The patient responded well to 21 days of broad spectrum antimicrobial therapy modified to ceftazidime alone following speciation and sensitivity. Outpatient follow-up at 46 days revealed normal maximal mouth opening with the ability to chew and tolerate a full diet. Trismus is a motor disturbance of the trigeminal nerve with difficulty in opening the mouth. Infectious etiologies commonly described include tetanus, odontogenic infections, or deep neck space infections. This is the first reported case of simultaneous nosocomial Pseudomonas meningitis and trismus in a patient with no history of neurosurgery or lumbar spinal manipulation.

  5. The action of Pseudomonas aeruginosa biofilms in intrinsic drug resistance.

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    Xie, Yi; Jia, Wen-xiang; Zeng, Wei; Yang, Wei-qing; Cheng, Xi; Li, Xue-ru; Wang, Lan-lan; Kang, Mei; Zhang, Zai-rong

    2005-10-05

    There is a growing interest in studying the relationship between intrinsic resistance and biofilms resistance to drugs. However, the relationship still remains unclear in the macroscopic bacterial growth. Our study is to illuminate the change of bacterial drug resistance of gyrA mutant and active efflux pump during the development of Pseudomonas aeruginosa (P. aeruginosa) biofilms. The strains of type II topoisomerase gene mutant (gyrA mutant) and multidrug resistance (MDR) efflux pump were clinical isolates and detected by polymerase chain reaction (PCR). The process of bacterial biofilms development was observed by scanning electron microscope. Triparental mating experiments were performed to transfer report gene of green fluorescent protein (GFP) into P. aeruginosa biofilms strains and followed by analysis of bacterial survival rate between intrinsic resistance and biofilms resistance. The fluorescent strains with pGFPuv could develop mature biofilms on Teflon surface. Before a period of 72 hours, the survival rate of biofilms bacteria and intrinsic resistance strains in ciprofloxacin solution was significantly different (P 0.05). The carbonyl cyanide m-chlorophenylhydrazone and azithromycin could significantly reduce the drug resistance of biofilm strains and efflux pump strains. In the development of P. aeruginosa biofilms, the strains of gyrA mutation and MDR efflux could be conferred with new level of drug resistance. When co-cultured mutated strains with biofilm strains, biofilms may play a major role in bacterial resistance. But after 72 hours incubation (a mature biofilms had been developed), there was no clearly difference between the number of mutant strains and biofilm strains.

  6. A functional type I topoisomerase from Pseudomonas aeruginosa

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    Roper Benjamin J

    2009-03-01

    Full Text Available Abstract Background Pseudomonas aeruginosa encodes a putative topoisomerase with sequence similarity to the eukaryotic type IB topoisomerase from Vaccinia virus. Residues in the active site are conserved, notably Tyr292 which would be predicted to form the transient covalent bond to DNA. Results The gene encoding the P. aeruginosa topoisomerase I was cloned and expressed in E. coli. The enzyme relaxes supercoiled DNA, while a mutant containing a Tyr292 to Phe substitution at the active site was found to be catalytically inert. This is consistent with the role of Tyr in forming the covalent intermediate. Like Vaccinia topoisomerase, the P. aeruginosa topoisomerase relaxes DNA in the absence of ATP, but unlike Vaccinia topoisomerase, P. aeruginosa topoisomerase does not relax supercoiled DNA without MgCl2 present. In addition, high concentration of NaCl is not able to substitute for MgCl2 as seen for Vaccinia topoisomerase. A truncated derivative of the topoisomerase lacking residues 1–98 relaxes DNA, with both full length and truncated enzyme exhibiting equivalent requirements for divalent cations and the ability to relax DNA to completion, suggesting a shared domain organization. DNA-binding assays suggest an only modest preference for the CCCTT pentameric sequence required for transesterification by Vaccinia topoisomerase IB. Conclusion P. aeruginosa encodes a functional topoisomerase with significant similarity to the type IB enzyme encoded by poxviruses. In contrast to the Vaccinia-encoded homolog, the P. aeruginosa-encoded enzyme requires divalent cations for catalytic activity, relaxes DNA to completion, and does not exhibit a strong preference for the pentameric sequence stringently required by the Vaccinia-encoded homolog. A comparison with the structure of poxviral topoisomerase in complex with DNA suggests that bacterial homologs of the eukaryotic type IB topoisomerase may exhibit a relaxed sequence preference due to the lack of

  7. Toxicogenomic response of Pseudomonas aeruginosa to ortho-phenylphenol

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    Toghrol Freshteh

    2008-10-01

    Full Text Available Abstract Background Pseudomonas aeruginosa (P. aeruginosa is the most common opportunistic pathogen implicated in nosocomial infections and in chronic lung infections in cystic fibrosis patients. Ortho-phenylphenol (OPP is an antimicrobial agent used as an active ingredient in several EPA registered disinfectants. Despite its widespread use, there is a paucity of information on its target molecular pathways and the cellular responses that it elucidates in bacteria in general and in P. aeruginosa in particular. An understanding of the OPP-driven gene regulation and cellular response it elicits will facilitate more effective utilization of this antimicrobial and possibly lead to the development of more effective disinfectant treatments. Results Herein, we performed a genome-wide transcriptome analysis of the cellular responses of P. aeruginosa exposed to 0.82 mM OPP for 20 and 60 minutes. Our data indicated that OPP upregulated the transcription of genes encoding ribosomal, virulence and membrane transport proteins after both treatment times. After 20 minutes of exposure to 0.82 mM OPP, genes involved in the exhibition of swarming motility and anaerobic respiration were upregulated. After 60 minutes of OPP treatment, the transcription of genes involved in amino acid and lipopolysaccharide biosynthesis were upregulated. Further, the transcription of the ribosome modulation factor (rmf and an alternative sigma factor (rpoS of RNA polymerase were downregulated after both treatment times. Conclusion Results from this study indicate that after 20 minutes of exposure to OPP, genes that have been linked to the exhibition of anaerobic respiration and swarming motility were upregulated. This study also suggests that the downregulation of the rmf and rpoS genes may be indicative of the mechanism by which OPP causes decreases in cell viability in P. aeruginosa. Consequently, a protective response involving the upregulation of translation leading to the

  8. MECANISMOS DE RESISTENCIA EN PSEUDOMONAS AERUGINOSA: ENTENDIENDO A UN PELIGROSO ENEMIGO Resistance mechanisms in Pseudomonas aeruginosa: understanding a dangerous enemy

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    Carlos Andrés Gómez Álvarez

    2005-01-01

    Full Text Available Pseudomonas aeruginosa es un bacilo Gram negativo no fermentador, ampliamente relacionado con la infección nosocomial. Este tipo de infecciones se presentan en pacientes severamente comprometidos, hospitalizados especialmente en unidades de cuidado intensivo, donde existe una alta presión de selección de resistencia por parte de los antibióticos. Estas infecciones nosocomiales tienen implicaciones en el pronóstico del paciente, los costos del tratamiento, la estancia hospitalaria, la morbilidad y la mortalidad. Es importante que en cada institución hospitalaria se mantenga una estrecha vigilancia de los perfiles de resistencia de esta bacteria, con el fin de reconocer sus mecanismos de resistencia, su evolución y la forma de transferencia. En este sentido, un concepto como "la lectura interpretativa del antibiograma" se impone y ayuda al clínico a inferir los posibles mecanismos de resistencia que exhibe la bacteria para de esta manera orientar el uso de la terapia antibiótica y avanzar en el gran desafío que implica enfrentar las consecuencias de la infección por P. aeruginosa.Pseudomonas aeruginosa is a Gram-negative fermentative bacilli related with nosocomial infections. This kind of infections is more frequent in critical ill patients, specially in intensive care units, where a high pressure selection is ejerxed. Nosocomial infections are associated with poor prognosis, increased treatment cost, cubed length, morbidity and mortality. Each health care institution might establish antimicrobial resistance surveillance in order to recognize antimicrobial resistance mechanisms, and transference of resistance of this pathogen. In the other hand, concepts as "interpretative reading" help the clinician to infer the possible mechanisms involved and in this way guide the antimicrobial therapy in order to boarding the challenge of this kind of infections.

  9. Adherence of Pseudomonas aeruginosa onto surfactant-laden contact lenses.

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    Mosuela, Reynalyn; Mustafa, Shelan; Gould, Simon; Hassanin, Hany; Alany, Raid G; ElShaer, Amr

    2018-03-01

    There is an immense research interest to utilise contact lens (CLs) as a popular platform for ocular drug delivery. However, CLs are the major predisposing factors of bacterial keratitis which is commonly caused by adhesion of microbes such as Pseudomonas aeruginosa and Staphylococcus epidermidis. The aim of the current study is to explore the effect of surfactants; Poloxamer 188, Polysorbate 80 and Tetronic ® 90R4 (at 0.25% - 3% v/v) on the characteristics of CLs and on the adhesion abilities of Pseudomonas aeruginosa to the lenses' surfaces. CLs were formulated using a hydrophilic monomer; 2-hydroxyethyl methacrylate (HEMA) together with silicone-based polymer such as Poly dimethyl siloxane (PDMS) or 3,3,3-trifluoropropylsilane (FSA) then lenses were polymerized under UV light. The formulated CLs with surfactants were found to have an increased equilibrium water content (EWC) due to hydrophilic moiety present in surfactants. A relationship was deduced between EWC and surface contact angle of lenses containing surfactants; where an increased EWC was associated with a decrease in contact angle reflecting a more hydrophilic surfaces of CLs. Apart from the 3% Polysorbate 80 (p Lenses with surfactants were found to have lower bacterial ATP concentration than lenses without surfactants. Poloxamer 188 in FSA lenses reduced bacterial adhesion from 4.22 × 10 -4  ± 1.30 × 10 -4 pM to 1.03 × 10 -4  ± 4.86 × 10 -5 pM, a reduction by 75.59% when compared to the control lenses (p = .002). Moreover, 1% Tetronic ® 90R4 in PDMS showed a reduction by 57.17% in ATP concentration. Polysorbate 80 in FSA exhibited the least bacterial adhesion with an average bacterial ATP concentration of 3.85 × 10 -5  ± 2.61 × 10 -5 pM; i.e 90.88% less bacterial ATP than control lenses (p = .001). Bioluminescence studies demonstrated a decrease in Pseudomonas aeruginosa adhesion to CLs containing surfactants without impairing the optical and

  10. A novel porcine model of ventilator-associated pneumonia caused by oropharyngeal challenge with Pseudomonas aeruginosa.

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    Li Bassi, Gianluigi; Rigol, Montserrat; Marti, Joan-Daniel; Saucedo, Lina; Ranzani, Otavio T; Roca, Ignasi; Cabanas, Maria; Muñoz, Laura; Giunta, Valeria; Luque, Nestor; Rinaudo, Mariano; Esperatti, Mariano; Fernandez-Barat, Laia; Ferrer, Miquel; Vila, Jordi; Ramirez, Jose; Torres, Antoni

    2014-05-01

    Animal models of ventilator-associated pneumonia (VAP) in primates, sheep, and pigs differ in the underlying pulmonary injury, etiology, bacterial inoculation methods, and time to onset. The most common ovine and porcine models do not reproduce the primary pathogenic mechanism of the disease, through the aspiration of oropharyngeal pathogens, or the most prevalent human etiology. Herein the authors characterize a novel porcine model of VAP due to aspiration of oropharyngeal secretions colonized by Pseudomonas aeruginosa. Ten healthy pigs were intubated, positioned in anti-Trendelenburg, and mechanically ventilated for 72 h. Three animals did not receive bacterial challenge, whereas in seven animals, a P. aeruginosa suspension was instilled into the oropharynx. Tracheal aspirates were cultured and respiratory mechanics were recorded. On autopsy, lobar samples were obtained to corroborate VAP through microbiological and histological studies. In animals not challenged, diverse bacterial colonization of the airways was found and monolobar VAP rarely developed. In animals with P. aeruginosa challenge, colonization of tracheal secretion increased up to 6.39 ± 0.34 log colony-forming unit (cfu)/ml (P < 0.001). VAP was confirmed in six of seven pigs, in 78% of the cases developed in the dependent lung segments (right medium and lower lobes, P = 0.032). The static respiratory system elastance worsened to 41.5 ± 5.8 cm H2O/l (P = 0.001). The authors devised a VAP model caused by aspiration of oropharyngeal P. aeruginosa, a frequent causative pathogen of human VAP. The model also overcomes the practical and legislative limitations associated with the use of primates. The authors' model could be employed to study pathophysiologic mechanisms, as well as novel diagnostic/preventive strategies.

  11. Characterization of the Newly Isolated Lytic Bacteriophages KTN6 and KT28 and Their Efficacy against Pseudomonas aeruginosa Biofilm.

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    Danis-Wlodarczyk, Katarzyna; Olszak, Tomasz; Arabski, Michal; Wasik, Slawomir; Majkowska-Skrobek, Grazyna; Augustyniak, Daria; Gula, Grzegorz; Briers, Yves; Jang, Ho Bin; Vandenheuvel, Dieter; Duda, Katarzyna Anna; Lavigne, Rob; Drulis-Kawa, Zuzanna

    2015-01-01

    We here describe two novel lytic phages, KT28 and KTN6, infecting Pseudomonas aeruginosa, isolated from a sewage sample from an irrigated field near Wroclaw, in Poland. Both viruses show characteristic features of Pbunalikevirus genus within the Myoviridae family with respect to shape and size of head/tail, as well as LPS host receptor recognition. Genome analysis confirmed the similarity to other PB1-related phages, ranging between 48 and 96%. Pseudomonas phage KT28 has a genome size of 66,381 bp and KTN6 of 65,994 bp. The latent period, burst size, stability and host range was determined for both viruses under standard laboratory conditions. Biofilm eradication efficacy was tested on peg-lid plate assay and PET membrane surface. Significant reduction of colony forming units was observed (70-90%) in 24 h to 72 h old Pseudomonas aeruginosa PAO1 biofilm cultures for both phages. Furthermore, a pyocyanin and pyoverdin reduction tests reveal that tested phages lowers the amount of both secreted dyes in 48-72 h old biofilms. Diffusion and goniometry experiments revealed the increase of diffusion rate through the biofilm matrix after phage application. These characteristics indicate these phages could be used to prevent Pseudomonas aeruginosa infections and biofilm formation. It was also shown, that PB1-related phage treatment of biofilm caused the emergence of stable phage-resistant mutants growing as small colony variants.

  12. Characterization of the Newly Isolated Lytic Bacteriophages KTN6 and KT28 and Their Efficacy against Pseudomonas aeruginosa Biofilm.

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    Katarzyna Danis-Wlodarczyk

    Full Text Available We here describe two novel lytic phages, KT28 and KTN6, infecting Pseudomonas aeruginosa, isolated from a sewage sample from an irrigated field near Wroclaw, in Poland. Both viruses show characteristic features of Pbunalikevirus genus within the Myoviridae family with respect to shape and size of head/tail, as well as LPS host receptor recognition. Genome analysis confirmed the similarity to other PB1-related phages, ranging between 48 and 96%. Pseudomonas phage KT28 has a genome size of 66,381 bp and KTN6 of 65,994 bp. The latent period, burst size, stability and host range was determined for both viruses under standard laboratory conditions. Biofilm eradication efficacy was tested on peg-lid plate assay and PET membrane surface. Significant reduction of colony forming units was observed (70-90% in 24 h to 72 h old Pseudomonas aeruginosa PAO1 biofilm cultures for both phages. Furthermore, a pyocyanin and pyoverdin reduction tests reveal that tested phages lowers the amount of both secreted dyes in 48-72 h old biofilms. Diffusion and goniometry experiments revealed the increase of diffusion rate through the biofilm matrix after phage application. These characteristics indicate these phages could be used to prevent Pseudomonas aeruginosa infections and biofilm formation. It was also shown, that PB1-related phage treatment of biofilm caused the emergence of stable phage-resistant mutants growing as small colony variants.

  13. Glycan involvement in the adhesion of Pseudomonas aeruginosa to tears.

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    Kautto, Liisa; Nguyen-Khuong, Terry; Everest-Dass, Arun; Leong, Andrea; Zhao, Zhenjun; Willcox, Mark D P; Packer, Nicolle H; Peterson, Robyn

    2016-04-01

    The human eye is constantly bathed by tears, which protect the ocular surface via a variety of mechanisms. The O-linked glycans of tear mucins have long been considered to play a role in binding to pathogens and facilitating their removal in the tear flow. Other conjugated glycans in tears could similarly contribute to pathogen binding and removal but have received less attention. In the work presented here we assessed the contribution of glycan moieties, in particular the protein attached N-glycans, presented by the broad complement of tear proteins to the adhesion of the opportunistic pathogen Pseudomonas aeruginosa, a leading cause of microbial keratitis and ulceration of the cornea. Our adhesion assay involved immobilising the macromolecular components of tears into the wells of a polyvinyl difluoride (PVDF) microtitre filter plate and probing the binding of fluorescently labelled bacteria. Three P. aeruginosa strains were studied: a cytotoxic strain (6206) and an invasive strain (6294) from eye infections, and an invasive strain (320) from a urinary tract infection (UTI). The ocular isolates adhered two to three times more to human tears than to human saliva or porcine gastric mucin, suggesting ocular niche-specific adaptation. Support for the role of the N-glycans carried by human tear proteins in the binding and removal of P. aeruginosa from the eye was shown by: 1) pre-incubation of the bacteria with free component sugars, galactose, mannose, fucose and sialyl lactose (or combination thereof) inhibiting adhesion of all the P. aeruginosa strains to the immobilised tear proteins, with the greatest inhibition of binding of the ocular cytotoxic 6206 and least for the invasive 6294 strain; 2) pre-incubation of the bacteria with N-glycans released from the commercially available human milk lactoferrin, an abundant protein that carries N-linked glycans in tears, inhibiting the adhesion to tears of the ocular bacteria by up to 70%, which was significantly more

  14. Pseudomonas aeruginosa serA Gene Is Required for Bacterial Translocation through Caco-2 Cell Monolayers.

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    Yasuda, Masashi; Nagata, Syouya; Yamane, Satoshi; Kunikata, Chinami; Kida, Yutaka; Kuwano, Koichi; Suezawa, Chigusa; Okuda, Jun

    2017-01-01

    To specify critical factors responsible for Pseudomonas aeruginosa penetration through the Caco-2 cell epithelial barrier, we analyzed transposon insertion mutants that demonstrated a dramatic reduction in penetration activity relative to P. aeruginosa PAO1 strain. From these strains, mutations could be grouped into five classes, specifically flagellin-associated genes, pili-associated genes, heat-shock protein genes, genes related to the glycolytic pathway, and biosynthesis-related genes. Of these mutants, we here focused on the serA mutant, as the association between this gene and penetration activity is yet unknown. Inactivation of the serA gene caused significant repression of bacterial penetration through Caco-2 cell monolayers with decreased swimming and swarming motilities, bacterial adherence, and fly mortality rate, as well as repression of ExoS secretion; however, twitching motility was not affected. Furthermore, L-serine, which is known to inhibit the D-3-phosphoglycerate dehydrogenase activity of the SerA protein, caused significant reductions in penetration through Caco-2 cell monolayers, swarming and swimming motilities, bacterial adherence to Caco-2 cells, and virulence in flies in the wild-type P. aeruginosa PAO1 strain. Together, these results suggest that serA is associated with bacterial motility and adherence, which are mediated by flagella that play a key role in the penetration of P. aeruginosa through Caco-2 cell monolayers. Oral administration of L-serine to compromised hosts might have the potential to interfere with bacterial translocation and prevent septicemia caused by P. aeruginosa through inhibition of serA function.

  15. Nitrite Formation from Hydroxylamine and Oximes by Pseudomonas aeruginosa

    Science.gov (United States)

    Amarger, Noelle; Alexander, M.

    1968-01-01

    Nitrite was formed from hydroxylamine and several oximes by intact cells and extracts of Pseudomonas aeruginosa. The activity was induced by the presence of oximes in the culture medium. Nitroalkanes were not intermediates in the conversion of acetaldoxime, acetone oxime, or butanone oxime to nitrite, since nitromethane inhibited the formation of nitrite from the nitro compounds but not from the corresponding oximes. The oxime apparently functions as a constant source of hydroxylamine during growth of the bacterium. Hydroxylamine at low concentration was converted stoichiometrically to nitrite by extracts of the bacterium; high concentrations were inhibitory. Nicotinamide adenine dinucleotide phosphate, oxygen, and other unidentified cofactors were necessary for the reaction. Actively nitrifying extracts possessed no hydroxylamine-cytochrome c reductase activity. Hyponitrite, nitrous oxide, and nitric oxide were not metabolized. PMID:4384968

  16. Novel multiscale modeling tool applied to Pseudomonas aeruginosa biofilm formation.

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    Matthew B Biggs

    Full Text Available Multiscale modeling is used to represent biological systems with increasing frequency and success. Multiscale models are often hybrids of different modeling frameworks and programming languages. We present the MATLAB-NetLogo extension (MatNet as a novel tool for multiscale modeling. We demonstrate the utility of the tool with a multiscale model of Pseudomonas aeruginosa biofilm formation that incorporates both an agent-based model (ABM and constraint-based metabolic modeling. The hybrid model correctly recapitulates oxygen-limited biofilm metabolic activity and predicts increased growth rate via anaerobic respiration with the addition of nitrate to the growth media. In addition, a genome-wide survey of metabolic mutants and biofilm formation exemplifies the powerful analyses that are enabled by this computational modeling tool.

  17. Novel multiscale modeling tool applied to Pseudomonas aeruginosa biofilm formation.

    Science.gov (United States)

    Biggs, Matthew B; Papin, Jason A

    2013-01-01

    Multiscale modeling is used to represent biological systems with increasing frequency and success. Multiscale models are often hybrids of different modeling frameworks and programming languages. We present the MATLAB-NetLogo extension (MatNet) as a novel tool for multiscale modeling. We demonstrate the utility of the tool with a multiscale model of Pseudomonas aeruginosa biofilm formation that incorporates both an agent-based model (ABM) and constraint-based metabolic modeling. The hybrid model correctly recapitulates oxygen-limited biofilm metabolic activity and predicts increased growth rate via anaerobic respiration with the addition of nitrate to the growth media. In addition, a genome-wide survey of metabolic mutants and biofilm formation exemplifies the powerful analyses that are enabled by this computational modeling tool.

  18. Antibacterial Coating for Elimination of Pseudomonas aeruginosa and Escherichia coli

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    Zainal Abidin Ali

    2014-01-01

    Full Text Available A polymer antibacterial surface has been successfully developed. The coating system used silane as binder and Ag particles as antibacterial agent. The silver was synthesized using precipitation method. X-ray diffraction (XRD, field emission scanning electron microscopy (FESEM, Brunauer-Emmett-Teller (BET tests, energy-dispersive X-ray spectroscopy (EDX, and X-ray photoelectron spectroscopy (XPS were carried out to evaluate the silver particles. Antibacterial properties of the coating system were tested against gram-negative bacteria, namely, Pseudomonas aeruginosa and Escherichia coli. Different amounts of Ag were used in the coating to optimize its usage. The Japanese International Standard, JISZ2801, was used for bacteria test and the surface developed complies with the standard being antibacterial.

  19. Production of biopolymers by Pseudomonas aeruginosa isolated from marine source

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    Nazia Jamil

    2008-06-01

    Full Text Available Two bacterial strains, Pseudomonas aeruginosa CMG607w and CMG1421 produce commercially important biopolymers. CMG607w isolated from the sediments of Lyari outfall to Arabian Sea synthesize the mcl-polyhydroxyalkanoates from various carbon sources. The production of PHAs was directly proportional to the incubation periods. Other strain CMG1421, a dry soil isolate, produced high viscous water absorbing extracellular acidic polysaccharide when it was grown aerobically in the minimal medium containing glucose or fructose or sucrose as sole source of carbon. The biopolymer had the ability to absorb water 400 times more than its dry weight. This property was superior to that of currently used non-degradable synthetic water absorbents. It acted as salt filter and had rheological and stabilizing activity as well.

  20. Nitrite formation from hydroxylamine and oximes by Pseudomonas aeruginosa.

    Science.gov (United States)

    Amarger, N; Alexander, M

    1968-05-01

    Nitrite was formed from hydroxylamine and several oximes by intact cells and extracts of Pseudomonas aeruginosa. The activity was induced by the presence of oximes in the culture medium. Nitroalkanes were not intermediates in the conversion of acetaldoxime, acetone oxime, or butanone oxime to nitrite, since nitromethane inhibited the formation of nitrite from the nitro compounds but not from the corresponding oximes. The oxime apparently functions as a constant source of hydroxylamine during growth of the bacterium. Hydroxylamine at low concentration was converted stoichiometrically to nitrite by extracts of the bacterium; high concentrations were inhibitory. Nicotinamide adenine dinucleotide phosphate, oxygen, and other unidentified cofactors were necessary for the reaction. Actively nitrifying extracts possessed no hydroxylamine-cytochrome c reductase activity. Hyponitrite, nitrous oxide, and nitric oxide were not metabolized.

  1. Pseudomonas aeruginosa Oligoribonuclease Contributes to Tolerance to Ciprofloxacin by Regulating Pyocin Biosynthesis.

    Science.gov (United States)

    Chen, Fei; Chen, Gukui; Liu, Yiwei; Jin, Yongxin; Cheng, Zhihui; Liu, Yang; Yang, Liang; Jin, Shouguang; Wu, Weihui

    2017-03-01

    Bacterial oligoribonuclease (Orn) is a conserved 3'-to-5' exonuclease. In Pseudomonas aeruginosa, it has been demonstrated that Orn plays a major role in the hydrolysis of pGpG, which is required for cyclic-di-GMP homeostasis. Meanwhile, Orn is involved in the degradation of nanoRNAs, which can alter global gene expression by serving as transcription initiation primers. Previously, we found that Orn is required for the type III secretion system and pathogenesis of P. aeruginosa, indicating a role of Orn in the bacterial response to environmental stimuli. Here we report that Orn is required for the tolerance of P. aeruginosa to ciprofloxacin. Transcriptome analysis of an orn mutant revealed the upregulation of pyocin biosynthesis genes. Mutation of genes involved in pyocin biosynthesis in the background of an orn mutant restored bacterial tolerance to ciprofloxacin. We further demonstrate that the upregulation of pyocin biosynthesis genes is due to RecA-mediated autoproteolysis of PrtR, which is the major negative regulator of pyocin biosynthesis genes. In addition, the SOS response genes were upregulated in the orn mutant, indicating a DNA damage stress. Therefore, our results revealed a novel role of Orn in bacterial tolerance to ciprofloxacin. Copyright © 2017 American Society for Microbiology.

  2. Multimodal chemical imaging of molecular messengers in emerging Pseudomonas aeruginosa bacterial communities.

    Science.gov (United States)

    Baig, Nameera F; Dunham, Sage J B; Morales-Soto, Nydia; Shrout, Joshua D; Sweedler, Jonathan V; Bohn, Paul W

    2015-10-07

    Two label-free molecular imaging techniques, confocal Raman microscopy (CRM) and secondary ion mass spectrometry (SIMS), are combined for in situ characterization of the spatiotemporal distributions of quinolone metabolites and signaling molecules in communities of the pathogenic bacterium Pseudomonas aeruginosa. Dramatic molecular differences are observed between planktonic and biofilm modes of growth for these bacteria. We observe patterned aggregation and a high abundance of N-oxide quinolines in early biofilms and swarm zones of P. aeruginosa, while the concentrations of these secreted components in planktonic cells and agar plate colonies are below CRM and SIMS detection limits. CRM, in conjunction with principal component analysis (PCA) is used to distinguish between the two co-localized isomeric analyte pairs 4-hydroxy-2-heptylquinoline-N-oxide (HQNO)/2-heptyl-3-hydroxyquinolone (PQS) and 4-hydroxy-2-nonylquinoline-N-oxide (NQNO)/2-nonyl-hydroxyquinolone (C9-PQS) based on differences in their vibrational fingerprints, illustrating how the technique can be used to guide tandem-MS and tandem-MS imaging analysis. Because N-oxide quinolines are ubiquitous and expressed early in biofilms, these analytes may be fundamentally important for early biofilm formation and the growth and organization of P. aeruginosa microbial communities. This study underscores the advantages of using multimodal molecular imaging to study complex biological systems.

  3. The Pseudomonas aeruginosa transcriptome in planktonic cultures and static biofilms using RNA sequencing.

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    Andreas Dötsch

    Full Text Available In this study, we evaluated how gene expression differs in mature Pseudomonas aeruginosa biofilms as opposed to planktonic cells by the use of RNA sequencing technology that gives rise to both quantitative and qualitative information on the transcriptome. Although a large proportion of genes were consistently regulated in both the stationary phase and biofilm cultures as opposed to the late exponential growth phase cultures, the global biofilm gene expression pattern was clearly distinct indicating that biofilms are not just surface attached cells in stationary phase. A large amount of the genes found to be biofilm specific were involved in adaptation to microaerophilic growth conditions, repression of type three secretion and production of extracellular matrix components. Additionally, we found many small RNAs to be differentially regulated most of them similarly in stationary phase cultures and biofilms. A qualitative analysis of the RNA-seq data revealed more than 3000 putative transcriptional start sites (TSS. By the use of rapid amplification of cDNA ends (5'-RACE we confirmed the presence of three different TSS associated with the pqsABCDE operon, two in the promoter of pqsA and one upstream of the second gene, pqsB. Taken together, this study reports the first transcriptome study on P. aeruginosa that employs RNA sequencing technology and provides insights into the quantitative and qualitative transcriptome including the expression of small RNAs in P. aeruginosa biofilms.

  4. Structure, function and regulation of Pseudomonas aeruginosa porins.

    Science.gov (United States)

    Chevalier, Sylvie; Bouffartigues, Emeline; Bodilis, Josselin; Maillot, Olivier; Lesouhaitier, Olivier; Feuilloley, Marc G J; Orange, Nicole; Dufour, Alain; Cornelis, Pierre

    2017-09-01

    Pseudomonas aeruginosa is a Gram-negative bacterium belonging to the γ-proteobacteria. Like other members of the Pseudomonas genus, it is known for its metabolic versatility and its ability to colonize a wide range of ecological niches, such as rhizosphere, water environments and animal hosts, including humans where it can cause severe infections. Another particularity of P. aeruginosa is its high intrinsic resistance to antiseptics and antibiotics, which is partly due to its low outer membrane permeability. In contrast to Enterobacteria, pseudomonads do not possess general diffusion porins in their outer membrane, but rather express specific channel proteins for the uptake of different nutrients. The major outer membrane 'porin', OprF, has been extensively investigated, and displays structural, adhesion and signaling functions while its role in the diffusion of nutrients is still under discussion. Other porins include OprB and OprB2 for the diffusion of glucose, the two small outer membrane proteins OprG and OprH, and the two porins involved in phosphate/pyrophosphate uptake, OprP and OprO. The remaining nineteen porins belong to the so-called OprD (Occ) family, which is further split into two subfamilies termed OccD (8 members) and OccK (11 members). In the past years, a large amount of information concerning the structure, function and regulation of these porins has been published, justifying why an updated review is timely. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Surface Sensing for Biofilm Formation in Pseudomonas aeruginosa

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    Chien-Yi Chang

    2018-01-01

    Full Text Available Aggregating and forming biofilms on biotic or abiotic surfaces are ubiquitous bacterial behaviors under various conditions. In clinical settings, persistent presence of biofilms increases the risks of healthcare-associated infections and imposes huge healthcare and economic burdens. Bacteria within biofilms are protected from external damage and attacks from the host immune system and can exchange genomic information including antibiotic-resistance genes. Dispersed bacterial cells from attached biofilms on medical devices or host tissues may also serve as the origin of further infections. Understanding how bacteria develop biofilms is pertinent to tackle biofilm-associated infections and transmission. Biofilms have been suggested as a continuum of growth modes for adapting to different environments, initiating from bacterial cells sensing their attachment to a surface and then switching cellular physiological status for mature biofilm development. It is crucial to understand bacterial gene regulatory networks and decision-making processes for biofilm formation upon initial surface attachment. Pseudomonas aeruginosa is one of the model microorganisms for studying bacterial population behaviors. Several hypotheses and studies have suggested that extracellular macromolecules and appendages play important roles in bacterial responses to the surface attachment. Here, I review recent studies on potential molecular mechanisms and signal transduction pathways for P. aeruginosa surface sensing.

  6. Effect of methylglyoxal on multidrug-resistant Pseudomonas aeruginosa

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    Katsuhiko eHayashi

    2014-04-01

    Full Text Available Honey has a complex chemistry, and its broad-spectrum antimicrobial activity varies with floral source, climate, and harvesting conditions. Methylglyoxal was identified as the dominant antibacterial component of manuka honey. Although it has been known that methylglyoxal has antibacterial activity against gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus, there is not much information describing its activity against gram-negative bacteria. In this study, we report the effect of methylglyoxal against multidrug-resistant Pseudomonas aeruginosa (MDRP using 53 clinically isolated strains. We also assessed the effect of deleting the five multidrug efflux systems in P. aeruginosa, as well as the efflux systems in Escherichia coli and Salmonella enterica serovar Typhimurium, on MICs of methylglyoxal. Our results indicate that methylglyoxal inhibits the growth of MDRP at concentrations of 128–512 µg/ml (1.7–7.1 mM and is not recognized by drug efflux systems.

  7. Identification of Pseudomonas aeruginosa phenazines that kill Caenorhabditis elegans.

    Science.gov (United States)

    Cezairliyan, Brent; Vinayavekhin, Nawaporn; Grenfell-Lee, Daniel; Yuen, Grace J; Saghatelian, Alan; Ausubel, Frederick M

    2013-01-01

    Pathogenic microbes employ a variety of methods to overcome host defenses, including the production and dispersal of molecules that are toxic to their hosts. Pseudomonas aeruginosa, a Gram-negative bacterium, is a pathogen of a diverse variety of hosts including mammals and the nematode Caenorhabditis elegans. In this study, we identify three small molecules in the phenazine class that are produced by P. aeruginosa strain PA14 that are toxic to C. elegans. We demonstrate that 1-hydroxyphenazine, phenazine-1-carboxylic acid, and pyocyanin are capable of killing nematodes in a matter of hours. 1-hydroxyphenazine is toxic over a wide pH range, whereas the toxicities of phenazine-1-carboxylic acid and pyocyanin are pH-dependent at non-overlapping pH ranges. We found that acidification of the growth medium by PA14 activates the toxicity of phenazine-1-carboxylic acid, which is the primary toxic agent towards C. elegans in our assay. Pyocyanin is not toxic under acidic conditions and 1-hydroxyphenazine is produced at concentrations too low to kill C. elegans. These results suggest a role for phenazine-1-carboxylic acid in mammalian pathogenesis because PA14 mutants deficient in phenazine production have been shown to be defective in pathogenesis in mice. More generally, these data demonstrate how diversity within a class of metabolites could affect bacterial toxicity in different environmental niches.

  8. Identification of Pseudomonas aeruginosa phenazines that kill Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Brent Cezairliyan

    2013-01-01

    Full Text Available Pathogenic microbes employ a variety of methods to overcome host defenses, including the production and dispersal of molecules that are toxic to their hosts. Pseudomonas aeruginosa, a Gram-negative bacterium, is a pathogen of a diverse variety of hosts including mammals and the nematode Caenorhabditis elegans. In this study, we identify three small molecules in the phenazine class that are produced by P. aeruginosa strain PA14 that are toxic to C. elegans. We demonstrate that 1-hydroxyphenazine, phenazine-1-carboxylic acid, and pyocyanin are capable of killing nematodes in a matter of hours. 1-hydroxyphenazine is toxic over a wide pH range, whereas the toxicities of phenazine-1-carboxylic acid and pyocyanin are pH-dependent at non-overlapping pH ranges. We found that acidification of the growth medium by PA14 activates the toxicity of phenazine-1-carboxylic acid, which is the primary toxic agent towards C. elegans in our assay. Pyocyanin is not toxic under acidic conditions and 1-hydroxyphenazine is produced at concentrations too low to kill C. elegans. These results suggest a role for phenazine-1-carboxylic acid in mammalian pathogenesis because PA14 mutants deficient in phenazine production have been shown to be defective in pathogenesis in mice. More generally, these data demonstrate how diversity within a class of metabolites could affect bacterial toxicity in different environmental niches.

  9. Identification of Pseudomonas aeruginosa Phenazines that Kill Caenorhabditis elegans

    Science.gov (United States)

    Cezairliyan, Brent; Vinayavekhin, Nawaporn; Grenfell-Lee, Daniel; Yuen, Grace J.; Saghatelian, Alan; Ausubel, Frederick M.

    2013-01-01

    Pathogenic microbes employ a variety of methods to overcome host defenses, including the production and dispersal of molecules that are toxic to their hosts. Pseudomonas aeruginosa, a Gram-negative bacterium, is a pathogen of a diverse variety of hosts including mammals and the nematode Caenorhabditis elegans. In this study, we identify three small molecules in the phenazine class that are produced by P. aeruginosa strain PA14 that are toxic to C. elegans. We demonstrate that 1-hydroxyphenazine, phenazine-1-carboxylic acid, and pyocyanin are capable of killing nematodes in a matter of hours. 1-hydroxyphenazine is toxic over a wide pH range, whereas the toxicities of phenazine-1-carboxylic acid and pyocyanin are pH-dependent at non-overlapping pH ranges. We found that acidification of the growth medium by PA14 activates the toxicity of phenazine-1-carboxylic acid, which is the primary toxic agent towards C. elegans in our assay. Pyocyanin is not toxic under acidic conditions and 1-hydroxyphenazine is produced at concentrations too low to kill C. elegans. These results suggest a role for phenazine-1-carboxylic acid in mammalian pathogenesis because PA14 mutants deficient in phenazine production have been shown to be defective in pathogenesis in mice. More generally, these data demonstrate how diversity within a class of metabolites could affect bacterial toxicity in different environmental niches. PMID:23300454

  10. Reactions of Pseudomonas aeruginosa pyocyanin with reduced glutathione.

    Science.gov (United States)

    Cheluvappa, Rajkumar; Shimmon, Ronald; Dawson, Michael; Hilmer, Sarah N; Le Couteur, David G

    2008-01-01

    Pseudomonas aeruginosa is the most common cause of chronic and recurrent lung infections in patients with cystic fibrosis (CF) whose sputa contain copious quantities of P. aeruginosa toxin, pyocyanin. Pyocyanin triggers tissue damage mainly by its redox cycling and induction of reactive oxygen species (ROS). The reactions between reduced glutathione (GSH) and pyocyanin were observed using absorption spectra from spectrophotometry and the reaction products analysed by nuclear magnetic resonance imaging. Pyocyanin reacted with GSH non-enzymatically at 37 degrees C resulting in the production of red-brown products, spectophotometrically visible as a 480 nm maximum absorption peak after 24 h of incubation. The reaction was concentration-dependent on reduced glutathione but not on pyocyanin. Minimizing the accessibility of oxygen to the reaction decreased its rate. The anti-oxidant enzyme catalase circumvented the reaction. Proton-NMR analysis demonstrated the persistence of the original aromatic ring and the methyl-group of pyocyanin in the red-brown products. Anti-oxidant agents having thiol groups produced similar spectophotometrically visible peaks. The presence of a previously unidentified non-enzymatic GSH-dependent metabolic pathway for pyocyanin has thus been identified. The reaction between pyocyanin and GSH is concentration-, time-, and O(2)-dependent. The formation of H(2)O(2) as an intermediate and the thiol group in GSH seem to be important in this reaction.

  11. Mechanical destruction of pseudomonas aeruginosa biofilms by ultrasound exposure

    Science.gov (United States)

    Xu, Jin; Bigelow, Timothy A.; Halverson, Larry J.; Middendorf, Jill; Rusk, Ben

    2012-10-01

    Medical implants are prone to colonization by bacterial biofilms, which are highly resistant to antibiotics. Normally, surgery is required to replace the infected implant. One promising non-invasive treatment option is to destroy the biofilm with high-intensity focused ultrasound (HIFU) exposure. In our study, Pseudomonas aeruginosa bacterial biofilms were grown on graphite disks in a flow chamber for three days prior to exposing them to ultrasound pulses of varying duration or burst period. The pulses were 20 cycles in duration at a frequency of 1.1 MHz from a spherically focused transducer (f/1, 63 mm focal length), creating peak compressional and rarefactional pressures at the disk surface of 30 and 13 MPa, respectively. P. aeruginosa were tagged with GFP and cells killed by HIFU were visualized using propidium iodide, which permeates membranes of dead cells, to aid determining the extent of biofilm destruction and whether cells are alive or dead. Our results indicate that a 30-s exposure and 6-ms pulse period or those combinations with the same number of pulses, were sufficient to destroy the biofilm and to kill the remaining cells. Reducing the number of pulses decreased biofilm destruction, leaving more dead and live bacteria on the surface.

  12. Assembly and development of the Pseudomonas aeruginosa biofilm matrix.

    Directory of Open Access Journals (Sweden)

    Luyan Ma

    2009-03-01

    Full Text Available Virtually all cells living in multicellular structures such as tissues and organs are encased in an extracellular matrix. One of the most important features of a biofilm is the extracellular polymeric substance that functions as a matrix, holding bacterial cells together. Yet very little is known about how the matrix forms or how matrix components encase bacteria during biofilm development. Pseudomonas aeruginosa forms environmentally and clinically relevant biofilms and is a paradigm organism for the study of biofilms. The extracellular polymeric substance of P. aeruginosa biofilms is an ill-defined mix of polysaccharides, nucleic acids, and proteins. Here, we directly visualize the product of the polysaccharide synthesis locus (Psl exopolysaccharide at different stages of biofilm development. During attachment, Psl is anchored on the cell surface in a helical pattern. This promotes cell-cell interactions and assembly of a matrix, which holds bacteria in the biofilm and on the surface. Chemical dissociation of Psl from the bacterial surface disrupted the Psl matrix as well as the biofilm structure. During biofilm maturation, Psl accumulates on the periphery of 3-D-structured microcolonies, resulting in a Psl matrix-free cavity in the microcolony center. At the dispersion stage, swimming cells appear in this matrix cavity. Dead cells and extracellular DNA (eDNA are also concentrated in the Psl matrix-free area. Deletion of genes that control cell death and autolysis affects the formation of the matrix cavity and microcolony dispersion. These data provide a mechanism for how P. aeruginosa builds a matrix and subsequently a cavity to free a portion of cells for seeding dispersal. Direct visualization reveals that Psl is a key scaffolding matrix component and opens up avenues for therapeutics of biofilm-related complications.

  13. Resistance of Animal Strains of Pseudomonas aeruginosa to Carbapenems

    Directory of Open Access Journals (Sweden)

    Marisa Haenni

    2017-09-01

    Full Text Available Carbapenems are major antibiotics reserved to human medicine. This study aimed to investigate the mechanisms of carbapenem resistance of a selection of Pseudomonas aeruginosa veterinary strains from the French network Resapath. Thirty (5.7% imipenem and/or meropenem non-susceptible P. aeruginosa of canine (n = 24, feline (n = 5, or bovine (n = 1 origin were identified in a large collection of 527 veterinary strains gathered by the Resapath. These resistant isolates belonged to 25 MultiLocus Sequence Types (MLST, of which 17 (68% are shared with clinical (human strains, such as high risk clones ST233 and ST395. Interestingly, none of the veterinary strains produced a carbapenemase, and only six of them (20% harbored deletions or insertion sequence (IS disrupting the porin OprD gene. The remaining 24 strains contained mutations or IS in various loci resulting in down-regulation of gene oprD coupled with upregulation of efflux system CzcCBA (n = 3; activation of sensor kinase CzcS ± CopS, MexEF-OprN (n = 4; alteration of oxido reductase MexS, MexXY (n = 8; activation of two-component system ParRS, or MexAB-OprM (n = 12; alteration of regulator MexR, NalC ± NalD. Two efflux pumps were co-produced simultaneously in three mutants. Finally, in 11 out of 12 strains displaying an intact porin OprD, derepression of MexAB-OprM accounted for a decreased susceptibility to meropenem relative to imipenem. Though not treated by carbapenems, animals thus represent a reservoir of multidrug resistant P. aeruginosa strains potentially able to contaminate fragile outpatients.

  14. Elevated paracellular glucose flux across cystic fibrosis airway epithelial monolayers is an important factor for Pseudomonas aeruginosa growth.

    Science.gov (United States)

    Garnett, James P; Gray, Michael A; Tarran, Robert; Brodlie, Malcolm; Ward, Christopher; Baker, Emma H; Baines, Deborah L

    2013-01-01

    People with cystic fibrosis (CF) who develop related diabetes (CFRD) have accelerated pulmonary decline, increased infection with antibiotic-resistant Pseudomonas aeruginosa and increased pulmonary exacerbations. We have previously shown that glucose concentrations are elevated in airway surface liquid (ASL) of people with CF, particularly in those with CFRD. We therefore explored the hypotheses that glucose homeostasis is altered in CF airway epithelia and that elevation of glucose flux into ASL drives increased bacterial growth, with an effect over and above other cystic fibrosis transmembrane conductance regulator (CFTR)-related ASL abnormalities. The aim of this study was to compare the mechanisms governing airway glucose homeostasis in CF and non-CF primary human bronchial epithelial (HBE) monolayers, under normal conditions and in the presence of Ps. aeruginosa filtrate. HBE-bacterial co-cultures were performed in the presence of 5 mM or 15 mM basolateral glucose to investigate how changes in blood glucose, such as those seen in CFRD, affects luminal Ps. aeruginosa growth. Calu-3 cell monolayers were used to evaluate the potential importance of glucose on Ps. aeruginosa growth, in comparison to other hallmarks of the CF ASL, namely mucus hyperviscosity and impaired CFTR-dependent fluid secretions. We show that elevation of basolateral glucose promotes the apical growth of Ps. aeruginosa on CF airway epithelial monolayers more than non-CF monolayers. Ps. aeruginosa secretions elicited more glucose flux across CF airway epithelial monolayers compared to non-CF monolayers which we propose increases glucose availability in ASL for bacterial growth. In addition, elevating basolateral glucose increased Ps. aeruginosa growth over and above any CFTR-dependent effects and the presence or absence of mucus in Calu-3 airway epithelia-bacteria co-cultures. Together these studies highlight the importance of glucose as an additional factor in promoting Ps. aeruginosa growth

  15. Elevated paracellular glucose flux across cystic fibrosis airway epithelial monolayers is an important factor for Pseudomonas aeruginosa growth.

    Directory of Open Access Journals (Sweden)

    James P Garnett

    Full Text Available People with cystic fibrosis (CF who develop related diabetes (CFRD have accelerated pulmonary decline, increased infection with antibiotic-resistant Pseudomonas aeruginosa and increased pulmonary exacerbations. We have previously shown that glucose concentrations are elevated in airway surface liquid (ASL of people with CF, particularly in those with CFRD. We therefore explored the hypotheses that glucose homeostasis is altered in CF airway epithelia and that elevation of glucose flux into ASL drives increased bacterial growth, with an effect over and above other cystic fibrosis transmembrane conductance regulator (CFTR-related ASL abnormalities. The aim of this study was to compare the mechanisms governing airway glucose homeostasis in CF and non-CF primary human bronchial epithelial (HBE monolayers, under normal conditions and in the presence of Ps. aeruginosa filtrate. HBE-bacterial co-cultures were performed in the presence of 5 mM or 15 mM basolateral glucose to investigate how changes in blood glucose, such as those seen in CFRD, affects luminal Ps. aeruginosa growth. Calu-3 cell monolayers were used to evaluate the potential importance of glucose on Ps. aeruginosa growth, in comparison to other hallmarks of the CF ASL, namely mucus hyperviscosity and impaired CFTR-dependent fluid secretions. We show that elevation of basolateral glucose promotes the apical growth of Ps. aeruginosa on CF airway epithelial monolayers more than non-CF monolayers. Ps. aeruginosa secretions elicited more glucose flux across CF airway epithelial monolayers compared to non-CF monolayers which we propose increases glucose availability in ASL for bacterial growth. In addition, elevating basolateral glucose increased Ps. aeruginosa growth over and above any CFTR-dependent effects and the presence or absence of mucus in Calu-3 airway epithelia-bacteria co-cultures. Together these studies highlight the importance of glucose as an additional factor in promoting Ps

  16. Study on Antibiotic compounds from Pseudomonas aeruginosa NO4 Strain

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Ji Young; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2011-05-15

    As important human and veterinary medicines, antibiotics are being produced and consumed in large quantities around the world. For example, more than 50 million pounds (22,000 tons) of antibiotics are produced in the U.S. each year and annual production in Germany is about 2,000 tons. Antibiotics are low molecular weight microbial metabolites that at low concentrations inhibit the growth of other microorganisms. Resistant bacteria may also spread and become broader infection-control problems, not only within health care institutions, but in communities as well. Clinically important bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a common cause of infection among hospitalized patients. Pseudomonas aeruginosa is a major cause of opportunistic infections among immunocompromised individuals. The spread of this organism in health care settings is often difficult to control due to the presence of multiple intrinsic and acquired mechanisms of antimicrobial resistance. In this study, we isolated novel bacterium which had strong antagonistic activity and separated antibiotic compounds from Pseudomonas sp., and analyzed characteristics and molecular weight of the antibiotic compound

  17. Comparative genome and transcriptome analysis reveals distinctive surface characteristics and unique physiological potentials of Pseudomonas aeruginosa ATCC 27853

    KAUST Repository

    Cao, Huiluo

    2017-06-12

    Pseudomonas aeruginosa ATCC 27853 was isolated from a hospital blood specimen in 1971 and has been widely used as a model strain to survey antibiotics susceptibilities, biofilm development, and metabolic activities of Pseudomonas spp.. Although four draft genomes of P. aeruginosa ATCC 27853 have been sequenced, the complete genome of this strain is still lacking, hindering a comprehensive understanding of its physiology and functional genome.Here we sequenced and assembled the complete genome of P. aeruginosa ATCC 27853 using the Pacific Biosciences SMRT (PacBio) technology and Illumina sequencing platform. We found that accessory genes of ATCC 27853 including prophages and genomic islands (GIs) mainly contribute to the difference between P. aeruginosa ATCC 27853 and other P. aeruginosa strains. Seven prophages were identified within the genome of P. aeruginosa ATCC 27853. Of the predicted 25 GIs, three contain genes that encode monoxoygenases, dioxygenases and hydrolases that could be involved in the metabolism of aromatic compounds. Surveying virulence-related genes revealed that a series of genes that encode the B-band O-antigen of LPS are lacking in ATCC 27853. Distinctive SNPs in genes of cellular adhesion proteins such as type IV pili and flagella biosynthesis were also observed in this strain. Colony morphology analysis confirmed an enhanced biofilm formation capability of ATCC 27853 on solid agar surface compared to Pseudomonas aeruginosa PAO1. We then performed transcriptome analysis of ATCC 27853 and PAO1 using RNA-seq and compared the expression of orthologous genes to understand the functional genome and the genomic details underlying the distinctive colony morphogenesis. These analyses revealed an increased expression of genes involved in cellular adhesion and biofilm maturation such as type IV pili, exopolysaccharide and electron transport chain components in ATCC 27853 compared with PAO1. In addition, distinctive expression profiles of the

  18. Specific IgA against Pseudomonas aeruginosa in severe COPD

    Directory of Open Access Journals (Sweden)

    Millares L

    2017-09-01

    Full Text Available Laura Millares,1–3 Sara Martí,2,4 Carmen Ardanuy,2,4 Josefina Liñares,2,4 Salud Santos,2,5 Jordi Dorca,5 Marian García-Nuñez,1–3,6 Sara Quero,3,6 Eduard Monsó2,7,8 1Department of Respiratory Medicine, Fundació Parc Taulí, Sabadell, Spain; 2CIBER de Enfermedades Respiratorias, CIBERES, Bunyola, Spain; 3Universitat Autònoma de Barcelona, Esfera UAB, Barcelona, Spain; 4Department of Microbiology, Hospital Universitari de Bellvitge-Universitat de Barcelona-IDIBELL, L’Hospitalet de Llobregat, Spain; 5Department of Respiratory Medicine, Hospital Universitari de Bellvitge-Universitat de Barcelona-IDIBELL, L’Hospitalet de Llobregat, Spain; 6Infectious Diseases Unit, Fundació Insitut d’Investigació GermansTrias i Pujol, Badalona, Spain; 7Department of Respiratory Medicine, Hospital Universitari Parc Taulí, Sabadell, Spain; 8Department of Medicine, Universitat Autònoma de Barcelona (UAB, Barcelona, Spain Background: The bronchial mucosa is protected by a specialized immune system focused on the prevention of colonization and infection by potentially pathogenic microorganisms (PPMs. Immunoglobulin A (IgA is the principal antibody involved in this mechanism. A defective immune barrier may facilitate the recurrent presence of PPMs in COPD.Purpose: The aim of this study was to determine IgA-mediated bronchial specific immune responses against Pseudomonas aeruginosa in stable patients with severe disease.Methods: COPD patients with good-quality sputum samples obtained during stability were included and classified according to the presence or absence of chronic bronchial colonization by P. aeruginosa. Levels of specific IgA for P. aeruginosa in sputum were determined by ELISA and expressed as ratios, using the pooled level of 10 healthy subjects as reference (optical density450 patient/control.Results: Thirty-six stable COPD patients were included, 15 of whom had chronic colonization by P. aeruginosa. Levels of specific IgA against P

  19. The Effect of Strict Segregation on Pseudomonas aeruginosa in Cystic Fibrosis Patients

    NARCIS (Netherlands)

    van Mansfeld, Rosa; de Vrankrijker, Angelica; Brimicombe, Roland; Heijerman, Harry; Teding van Berkhout, Ferdinand; Spitoni, Cristian|info:eu-repo/dai/nl/304625957; Grave, Sanne; van der Ent, Cornelis; Wolfs, Tom; Willems, Rob; Bonten, Marc

    2016-01-01

    INTRODUCTION: Segregation of patients with cystic fibrosis (CF) was implemented to prevent chronic infection with epidemic Pseudomonas aeruginosa strains with presumed detrimental clinical effects, but its effectiveness has not been carefully evaluated. METHODS: The effect of strict segregation on

  20. Pseudomonas aeruginosa biofilm infections in cystic fibrosis: insights into pathogenic processes and treatment strategies

    DEFF Research Database (Denmark)

    Hassett, Daniel J; Korfhagen, Thomas R; Irvin, Randall T

    2010-01-01

    CF airway mucus can be infected by opportunistic microorganisms, notably Pseudomonas aeruginosa. Once organisms are established as biofilms, even the most potent antibiotics have little effect on their viability, especially during late-stage chronic infections. Better understanding...

  1. Antibiotic therapy against Pseudomonas aeruginosa in cystic fibrosis : a European consensus

    NARCIS (Netherlands)

    Döring, G; Conway, S P; Heijerman, H G; Hodson, M E; Høiby, N; Smyth, A; Touw, D J

    2000-01-01

    Cystic fibrosis (CF) is the most common lethal hereditary disorder with autosomal recessive heredity in caucasians. The majority of CF patients suffer from chronic respiratory infection with the opportunistic bacterial pathogen Pseudomonas aeruginosa. No consensus among clinicians has been reached

  2. Flavonoids from Rhizophora conjugata fruit extract blocks virulence factors of Pseudomonas aeruginosa

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, D.; Tilvi, S.; DeSouza, L.

    Pseudomonas aeruginosa is a major nosocomial pathogen which causes hospital acquired infections and recently has gained importance as a model to study antibiotic resistance. In the present study, we investigated the effect of methanol and methanol...

  3. Quorum sensing is necessary for the virulence of Pseudomonas aeruginosa during urinary tract infection

    National Research Council Canada - National Science Library

    Kumar, Ravi; Chhibber, Sanjay; Harjai, Kusum

    2009-01-01

    .... To understand the role of quorum sensing in pathogenesis of urinary tract infections, wild type Pseudomonas aeruginosa, having both functional las and rhl quorum sensing systems, and its isogenic...

  4. Quorum Sensing and Virulence of Pseudomonas aeruginosa during Lung Infection of Cystic Fibrosis Patients

    DEFF Research Database (Denmark)

    Bjarnsholt, T.; Jensen, P.O.; Jakobsen, T.H.

    2010-01-01

    Pseudomonas aeruginosa is the predominant microorganism in chronic lung infection of cystic fibrosis patients. The chronic lung infection is preceded by intermittent colonization. When the chronic infection becomes established, it is well accepted that the isolated strains differ phenotypically...

  5. Dynamics of mutations during development of resistance by Pseudomonas aeruginosa against five antibiotics

    NARCIS (Netherlands)

    Feng, Y.; Jonker, M.J.; Moustakas, I.; Brul, S.; ter Kuile, B.H.

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that causes considerable morbidity and mortality, specifically in the intensive care. Antibiotic resistant variants of this organism are more difficult to treat and cause substantial extra costs compared to susceptible strains. In the laboratory,

  6. Quinolone Signaling in the Cell-to-Cell Communication System of Pseudomonas aeruginosa

    National Research Council Canada - National Science Library

    Everett C. Pesci; Jared B. J. Milbank; James P. Pearson; Susan McKnight; Andrew S. Kende; E. Peter Greenberg; Barbara H. Iglewski

    1999-01-01

    ...) that consists of a homoserine lactone with a fatty acid side chain. Such is the case in the opportunistic human pathogen Pseudomonas aeruginosa, which contains two quorum sensing systems (las and rhl...

  7. Evolution of the Pseudomonas aeruginosa mutational resistome in an international Cystic Fibrosis clone

    DEFF Research Database (Denmark)

    López-Causapé, Carla; Madsen Sommer, Lea Mette; Cabot, Gabriel

    2017-01-01

    Emergence of epidemic clones and antibiotic resistance development compromises the management of Pseudomonas aeruginosa cystic fibrosis (CF) chronic respiratory infections. Whole genome sequencing (WGS) was used to decipher the phylogeny, interpatient dissemination, WGS mutator genotypes (mutome)...

  8. Epidemiology and Ecology of Opportunistic Premise Plumbing Pathogens: Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa

    Science.gov (United States)

    BACKGROUND: Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa are opportunistic premise plumbing pathogens (OPPPs) that persist and grow in household plumbing, habitats they share with humans. Infections caused by these OPPPs involve individuals with preexis...

  9. Contribution of cell elongation to the biofilm formation of Pseudomonas aeruginosa during anaerobic respiration

    National Research Council Canada - National Science Library

    Yoon, Mi Young; Lee, Kang-Mu; Park, Yongjin; Yoon, Sang Sun

    2011-01-01

    Pseudomonas aeruginosa, a gram-negative bacterium of clinical importance, forms more robust biofilm during anaerobic respiration, a mode of growth presumed to occur in abnormally thickened mucus layer...

  10. Allantoinase from Pseudomonas Aeruginosa. Purification, Properties and Immunochemical Characterization of Its In Vivo Inactivation

    NARCIS (Netherlands)

    Janssen, Dick B.; Smits, Rob A.M.M.; Drift, Chris van der

    1982-01-01

    The catabolic enzyme allantoinase is rapidly inactivated in cells of Pseudomonas aeruginosa when the stationary phase of growth is reached. This process is irreversible since the protein synthesis inhibitor chloramphenicol completely blocked the reappearance of allantoinase activity that is observed

  11. Inhibition of human monocyte chemotaxis and chemiluminescence by Pseudomonas aeruginosa elastase

    DEFF Research Database (Denmark)

    Kharazmi, A; Nielsen, H

    1991-01-01

    The in vitro effect of Pseudomonas aeruginosa elastase on human monocyte function was examined. Mononuclear cells isolated from the peripheral blood of healthy individuals were incubated with various concentrations of elastase, and the chemotactic activity and chemiluminescence response of these ...

  12. Polymorphonuclear leucocytes consume oxygen in sputum from chronic Pseudomonas aeruginosa pneumonia in cystic fibrosis

    DEFF Research Database (Denmark)

    Kolpen, Mette; Hansen, C. R.; Bjarnsholt, Thomas

    2010-01-01

    BACKGROUND: Chronic lung infection with Pseudomonas aeruginosa is the most severe complication for patients with cystic fibrosis (CF). This infection is characterised by endobronchial mucoid biofilms surrounded by numerous polymorphonuclear leucocytes (PMNs). The mucoid phenotype offers protection...... against the PMNs, which are in general assumed to mount an active respiratory burst leading to lung tissue deterioration. An ongoing respiratory burst by the PMNs has, however, not been demonstrated previously in endobronchial secretions from chronically infected patients with CF. OBJECTIVE: Based...... on the accumulating evidence for depletion of molecular oxygen (O(2)) in the mucus in infected CF bronchi, it was hypothesised that the O(2) depletion in the mucus in infected CF bronchi may be accelerated by the respiratory burst of the PMNs due to the reduction of O(2) to the superoxide anion (O(-)(2...

  13. Pyocyanin effects on respiratory epithelium: relevance in Pseudomonas aeruginosa airway infections.

    Science.gov (United States)

    Rada, Balázs; Leto, Thomas L

    2013-02-01

    Pseudomonas aeruginosa (PA) uses several virulence factors to establish chronic respiratory infections in bronchiectasis, chronic obstructive pulmonary disease, and cystic fibrosis (CF) patients. One of its toxins, pyocyanin (PYO), is a redox-active pigment that is required for full virulence in animal models and has been detected in patients' airway secretions. PYO promotes virulence by interfering with several cellular functions in host cells including electron transport, cellular respiration, energy metabolism, gene expression, and innate immune mechanisms. This review summarizes recent advances in PYO biology with special attention to current views on its role in human airway infections and on its interactions with the first line of our airway defense, the respiratory epithelium. Published by Elsevier Ltd.

  14. Análise epidemiológica de isolados clínicos de Pseudomonas aeruginosa provenientes de hospital universitário Epidemiologic analysis of clinical isolates of Pseudomonas aeruginosa from an university hospital

    Directory of Open Access Journals (Sweden)

    Eduardo José Valença Cordeiro Pires

    2009-12-01

    Full Text Available OBJETIVOS: A Pseudomonas aeruginosa é um patógeno oportunista que tem se destacado quanto à prevalência em casos de infecções hospitalares. Sua ampla resistência aos diversos grupos de antimicrobianos garante a este microrganismo um papel de destaque entre as bactérias mais prevalentes associadas à infecção nosocomial. O objetivo deste estudo foi realizar um levantamento epidemiológico da P. aeruginosa, bem como do seu perfil de susceptibilidade aos antimicrobianos no Hospital das Clínicas da Universidade Federal de Pernambuco. MÉTODOS: Foi realizado um estudo retrospectivo baseado no livro de registro de secreções diversas do laboratório de bacteriologia do Hospital das Clínicas no período compreendido entre janeiro a junho de 2008. Entre os registros, identificamos aqueles que foram positivos para a P. aeruginosa, analisando sua origem e perfil de susceptibilidade aos antimicrobianos utilizados na rotina daquele laboratório. RESULTADOS: As bactérias mais freqüentes, isoladas das secreções diversas, foram P. aeruginosa (26% e S. aureus (25%. Quanto à origem, a P. aeruginosa foi isolada principalmente de infecções respiratórias, pois 33% das amostras positivas para esta bactéria foram provinientes de secreções traqueais e 21% nasais. Os antimicrobianos mais eficazes contra a P. aeruginosa foram: amicacina, imipenem, meropenem e aztreonam. CONCLUSÕES: Estes resultados mostram uma alta prevalência de P. aeruginosa, no Hospital das Clínicas da Universidade Federal de Pernambuco. Apesar de apresentar grande resistência a antimicrobianos mais antigos como as cefalosporinas de primeira e segunda geração, assim como cloranfenicol, em geral, este patógeno demonstrou boa sensibilidade às drogas utilizadas na rotina deste hospital.OBJECTIVES: Pseudomonas aeruginosa is an increasingly prevalent opportunistic pathogen in hospital infection cases. Its high resistance rates to many antimicrobials has given this

  15. Trehalose biosynthesis promotes Pseudomonas aeruginosa pathogenicity in plants.

    Science.gov (United States)

    Djonović, Slavica; Urbach, Jonathan M; Drenkard, Eliana; Bush, Jenifer; Feinbaum, Rhonda; Ausubel, Jonathan L; Traficante, David; Risech, Martina; Kocks, Christine; Fischbach, Michael A; Priebe, Gregory P; Ausubel, Frederick M

    2013-03-01

    Pseudomonas aeruginosa strain PA14 is a multi-host pathogen that infects plants, nematodes, insects, and vertebrates. Many PA14 factors are required for virulence in more than one of these hosts. Noting that plants have a fundamentally different cellular architecture from animals, we sought to identify PA14 factors that are specifically required for plant pathogenesis. We show that synthesis by PA14 of the disaccharide trehalose is required for pathogenesis in Arabidopsis, but not in nematodes, insects, or mice. In-frame deletion of two closely-linked predicted trehalose biosynthetic operons, treYZ and treS, decreased growth in Arabidopsis leaves about 50 fold. Exogenously co-inoculated trehalose, ammonium, or nitrate, but not glucose, sulfate, or phosphate suppressed the phenotype of the double ΔtreYZΔtreS mutant. Exogenous trehalose or ammonium nitrate does not suppress the growth defect of the double ΔtreYZΔtreS mutant by suppressing the plant defense response. Trehalose also does not function intracellularly in P. aeruginosa to ameliorate a variety of stresses, but most likely functions extracellularly, because wild-type PA14 rescued the in vivo growth defect of the ΔtreYZΔtreS in trans. Surprisingly, the growth defect of the double ΔtreYZΔtreS double mutant was suppressed by various Arabidopsis cell wall mutants that affect xyloglucan synthesis, including an xxt1xxt2 double mutant that completely lacks xyloglucan, even though xyloglucan mutants are not more susceptible to pathogens and respond like wild-type plants to immune elicitors. An explanation of our data is that trehalose functions to promote the acquisition of nitrogen-containing nutrients in a process that involves the xyloglucan component of the plant cell wall, thereby allowing P. aeruginosa to replicate in the intercellular spaces in a leaf. This work shows how P. aeruginosa, a multi-host opportunistic pathogen, has repurposed a highly conserved "house-keeping" anabolic pathway (trehalose

  16. Trehalose biosynthesis promotes Pseudomonas aeruginosa pathogenicity in plants.

    Directory of Open Access Journals (Sweden)

    Slavica Djonović

    2013-03-01

    Full Text Available Pseudomonas aeruginosa strain PA14 is a multi-host pathogen that infects plants, nematodes, insects, and vertebrates. Many PA14 factors are required for virulence in more than one of these hosts. Noting that plants have a fundamentally different cellular architecture from animals, we sought to identify PA14 factors that are specifically required for plant pathogenesis. We show that synthesis by PA14 of the disaccharide trehalose is required for pathogenesis in Arabidopsis, but not in nematodes, insects, or mice. In-frame deletion of two closely-linked predicted trehalose biosynthetic operons, treYZ and treS, decreased growth in Arabidopsis leaves about 50 fold. Exogenously co-inoculated trehalose, ammonium, or nitrate, but not glucose, sulfate, or phosphate suppressed the phenotype of the double ΔtreYZΔtreS mutant. Exogenous trehalose or ammonium nitrate does not suppress the growth defect of the double ΔtreYZΔtreS mutant by suppressing the plant defense response. Trehalose also does not function intracellularly in P. aeruginosa to ameliorate a variety of stresses, but most likely functions extracellularly, because wild-type PA14 rescued the in vivo growth defect of the ΔtreYZΔtreS in trans. Surprisingly, the growth defect of the double ΔtreYZΔtreS double mutant was suppressed by various Arabidopsis cell wall mutants that affect xyloglucan synthesis, including an xxt1xxt2 double mutant that completely lacks xyloglucan, even though xyloglucan mutants are not more susceptible to pathogens and respond like wild-type plants to immune elicitors. An explanation of our data is that trehalose functions to promote the acquisition of nitrogen-containing nutrients in a process that involves the xyloglucan component of the plant cell wall, thereby allowing P. aeruginosa to replicate in the intercellular spaces in a leaf. This work shows how P. aeruginosa, a multi-host opportunistic pathogen, has repurposed a highly conserved "house-keeping" anabolic

  17. Biofilm Formation Mechanisms of Pseudomonas aeruginosa Predicted via Genome-Scale Kinetic Models of Bacterial Metabolism

    Science.gov (United States)

    2016-03-15

    RESEARCH ARTICLE Biofilm Formation Mechanisms of Pseudomonas aeruginosa Predicted via Genome-Scale Kinetic Models of Bacterial Metabolism Francisco G...jaques.reifman.civ@mail.mil Abstract A hallmark of Pseudomonas aeruginosa is its ability to establish biofilm -based infections that are difficult to...eradicate. Biofilms are less susceptible to host inflammatory and immune responses and have higher antibiotic tolerance than free-living planktonic

  18. Identification of small molecule inhibitors of Pseudomonas aeruginosa exoenzyme S using a yeast phenotypic screen.

    OpenAIRE

    Anthony Arnoldo; Jasna Curak; Saranya Kittanakom; Igor Chevelev; Vincent T Lee; Mehdi Sahebol-Amri; Becky Koscik; Lana Ljuma; Peter J Roy; Antonio Bedalov; Guri Giaever; Corey Nislow; A Rod Merrill; Stephen Lory; Igor Stagljar

    2008-01-01

    Pseudomonas aeruginosa is an opportunistic human pathogen that is a key factor in the mortality of cystic fibrosis patients, and infection represents an increased threat for human health worldwide. Because resistance of Pseudomonas aeruginosa to antibiotics is increasing, new inhibitors of pharmacologically validated targets of this bacterium are needed. Here we demonstrate that a cell-based yeast phenotypic assay, combined with a large-scale inhibitor screen, identified small molecule inhibi...

  19. Antimicrobial Susceptibility Pattern of Pseudomonas aeruginosa Isolated from Patients Referring to Hospitals

    OpenAIRE

    Zeynab Golshani; Ali Mohammad Ahadi; Ali Sharifzadeh

    2012-01-01

    Please cite this article as: Golshani Z, Ahadi AM, Sharifzadeh A. Antimicrobial Susceptibility Pattern of Pseudomonas aeruginosa Isolated from Patients Referring to Hospitals. Arch Hyg Sci 2012;1(2):48-53. Abstract: Background & Aims of the Study: The aim of this study was to detect and survey the antibiotic resistance pattern of Pseudomonas (P.) aeruginosa isolated from patients in Isfahan (located in central Iran) hospitals. Materials & Methods : A Total of 50 clinical isola...

  20. Photodynamic antimicrobial therapy to inhibit pseudomonas aeruginosa of corneal isolates (Conference Presentation)

    Science.gov (United States)

    Durkee, Heather A.; Relhan, Nidhi; Arboleda, Alejandro; Halili, Francisco; De Freitas, Carolina; Alawa, Karam; Aguilar, Mariela C.; Amescua, Guillermo; Miller, Darlene; Parel, Jean-Marie

    2016-03-01

    Keratitis associated with Pseudomonas aeruginosa is difficult to manage. Treatment includes antibiotic eye drops, however, some strains of Pseudomonas aeruginosa are resistant. Current research efforts are focused on finding alternative and adjunct therapies to treat multi-drug resistant bacteria. One promising alternate technique is photodynamic therapy (PDT). The purpose of this study was to evaluate the effect of riboflavin- and rose bengal-mediated PDT on Pseudomonas aeruginosa keratitis isolates in vitro. Two isolates (S+U- and S-U+) of Pseudomonas aeruginosa were derived from keratitis patients and exposed to five experimental groups: (1) Control (dark, UV-A irradiation, 525nm irradiation); (2) 0.1% riboflavin (dark, UV-A irradiation); and (3) 0.1% rose bengal, (4) 0.05% rose bengal and (5) 0.01% rose bengal (dark, 525nm irradiation). Three days after treatment, in dark conditions of all concentration of riboflavin and rose bengal showed no inhibition in both S+U- and S-U+ strains of Pseudomonas aeruginosa. In 0.1% and 0.05% rose bengal irradiated groups, for both S+U- and S-U+ strains, there was complete inhibition of bacterial growth in the central 50mm zone corresponding to the diameter of the green light source. These in vitro results suggest that rose bengal photodynamic therapy may be an effective adjunct treatment for Pseudomonas aeruginosa keratitis.

  1. Azithromycin increases in vitro fibronectin production through interactions between macrophages and fibroblasts stimulated with Pseudomonas aeruginosa

    Science.gov (United States)

    Cory, Theodore J.; Birket, Susan E.; Murphy, Brian S.; Mattingly, Cynthia; Breslow-Deckman, Jessica M.; Feola, David J.

    2013-01-01

    Objectives Chronic azithromycin therapy has been associated with improved clinical outcomes in patients with cystic fibrosis (CF) who are chronically infected with Pseudomonas aeruginosa. We have previously demonstrated that azithromycin polarizes macrophages towards an alternatively activated phenotype, thereby blunting inflammation associated with infection. Because this phenotype is pro-fibrotic, it is important to evaluate azithromycin's consequential effects upon fibroblast function and extracellular matrix (ECM) protein production. Methods We co-cultured macrophages and fibroblasts together and stimulated them by adding P. aeruginosa or lipopolysaccharide to assess the ability of azithromycin to alter the macrophage phenotype, along with the impact exerted upon the production of fibronectin and other effectors that govern tissue remodelling, including transforming growth factor β (TGFβ), matrix metalloproteinase-9 (MMP-9) and arginase. We supported these studies by evaluating the impact of azithromycin treatment on these proteins in a mouse model of P. aeruginosa infection. Results Azithromycin increased arginase expression in vitro, as well as the activation of latent TGFβ, consistent with polarization to the alternative macrophage phenotype. While the drug increased fibronectin concentrations after stimulation in vitro, secretion of the ECM-degrading enzyme MMP-9 was also increased. Neutralization of active TGFβ resulted in the ablation of azithromycin's ability to increase fibronectin concentrations, but did not alter its ability to increase MMP-9 expression. In P. aeruginosa-infected mice, azithromycin significantly decreased MMP-9 and fibronectin concentrations in the alveolar space compared with non-treated, infected controls. Conclusions Our results suggest that azithromycin's effect on MMP-9 is regulated independently of TGFβ activity. Additionally, the beneficial effects of azithromycin may be partially due to effects on homeostasis in which ECM

  2. Structural and functional characterization of Pseudomonas aeruginosa CupB chaperones.

    Directory of Open Access Journals (Sweden)

    Xun Cai

    Full Text Available Pseudomonas aeruginosa, an important human pathogen, is estimated to be responsible for ∼10% of nosocomial infections worldwide. The pathogenesis of P. aeruginosa starts from its colonization in the damaged tissue or medical devices (e.g. catheters, prothesis and implanted heart valve etc. facilitated by several extracellular adhesive factors including fimbrial pili. Several clusters containing fimbrial genes have been previously identified on the P. aeruginosa chromosome and named cup[1]. The assembly of the CupB pili is thought to be coordinated by two chaperones, CupB2 and CupB4. However, due to the lack of structural and biochemical data, their chaperone activities remain speculative. In this study, we report the 2.5 Å crystal structure of P. aeruginosa CupB2. Based on the structure, we further tested the binding specificity of CupB2 and CupB4 towards CupB1 (the presumed major pilus subunit and CupB6 (the putative adhesin using limited trypsin digestion and strep-tactin pull-down assay. The structural and biochemical data suggest that CupB2 and CupB4 might play different, but not redundant, roles in CupB secretion. CupB2 is likely to be the chaperone of CupB1, and CupB4 could be the chaperone of CupB4:CupB5:CupB6, in which the interaction of CupB4 and CupB6 might be mediated via CupB5.

  3. Pseudomonas aeruginosa elastase provides an escape from phagocytosis by degrading the pulmonary surfactant protein-A.

    Directory of Open Access Journals (Sweden)

    Zhizhou Kuang

    Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen that causes both acute pneumonitis in immunocompromised patients and chronic lung infections in individuals with cystic fibrosis and other bronchiectasis. Over 75% of clinical isolates of P. aeruginosa secrete elastase B (LasB, an elastolytic metalloproteinase that is encoded by the lasB gene. Previously, in vitro studies have demonstrated that LasB degrades a number of components in both the innate and adaptive immune systems. These include surfactant proteins, antibacterial peptides, cytokines, chemokines and immunoglobulins. However, the contribution of LasB to lung infection by P. aeruginosa and to inactivation of pulmonary innate immunity in vivo needs more clarification. In this study, we examined the mechanisms underlying enhanced clearance of the ΔlasB mutant in mouse lungs. The ΔlasB mutant was attenuated in virulence when compared to the wild-type strain PAO1 during lung infection in SP-A+/+ mice. However, the ΔlasB mutant was as virulent as PAO1 in the lungs of SP-A⁻/⁻ mice. Detailed analysis showed that the ΔlasB mutant was more susceptible to SP-A-mediated opsonization but not membrane permeabilization. In vitro and in vivo phagocytosis experiments revealed that SP-A augmented the phagocytosis of ΔlasB mutant bacteria more efficiently than the isogenic wild-type PAO1. The ΔlasB mutant was found to have a severely reduced ability to degrade SP-A, consequently making it unable to evade opsonization by the collectin during phagocytosis. These results suggest that P. aeruginosa LasB protects against SP-A-mediated opsonization by degrading the collectin.

  4. Friend or foe: genetic and functional characterization of plant endophytic Pseudomonas aeruginosa.

    Science.gov (United States)

    Kumar, A; Munder, A; Aravind, R; Eapen, S J; Tümmler, B; Raaijmakers, J M

    2013-03-01

    Endophytic Pseudomonas aeruginosa strain BP35 was originally isolated from black pepper grown in the rain forest in Kerala, India. Strain PaBP35 was shown to provide significant protection to black pepper against infections by Phytophthora capsici and Radopholus similis. For registration and implementation in disease management programmes, several traits of PaBP35 were investigated including its endophytic behaviour, biocontrol activity, phylogeny and toxicity to mammals. The results showed that PaBP35 efficiently colonized black pepper shoots and displayed a typical spatiotemporal pattern in its endophytic movement with concomitant suppression of Phytophthora rot. Confocal laser scanning microscopy revealed high populations of PaBP35::gfp2 inside tomato plantlets, supporting its endophytic behaviour in other plant species. Polyphasic approaches to genotype PaBP35, including BOX-PCR, recN sequence analysis, multilocus sequence typing and comparative genome hybridization analysis, revealed its uniqueness among P. aeruginosa strains representing clinical habitats. However, like other P. aeruginosa strains, PaBP35 exhibited resistance to antibiotics, grew at 25-41°C and produced rhamnolipids and phenazines. PaBP35 displayed strong type II secretion effectors-mediated cytotoxicity on mammalian A549 cells. Coupled with pathogenicity in a murine airway infection model, we conclude that this plant endophytic strain is as virulent as clinical P. aeruginosa strains. Safety issues related to the selection of plant endophytic bacteria for crop protection are discussed. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  5. Gauging and visualizing c-di-GMP levels in pseudomonas aeruginosa using fluorescence-based biosensors

    DEFF Research Database (Denmark)

    Rybtke, Morten; Chua, Song Lin; Yam, Joey Kuok Hoong

    2017-01-01

    developed a collection of fluorescence-based c-di-GMP biosensors capable of gauging the c-di-GMP level in Pseudomonas aeruginosa and closely related bacteria. Here, we describe protocols for the use of these biosensors in gauging and visualizing cellular c-di-GMP levels of P. aeruginosa both in in vitro...

  6. Evolutionary insight from whole-genome sequencing of Pseudomonas aeruginosa from cystic fibrosis patients

    DEFF Research Database (Denmark)

    Marvig, Rasmus Lykke; Madsen Sommer, Lea Mette; Jelsbak, Lars

    2015-01-01

    The opportunistic pathogen Pseudomonas aeruginosa causes chronic airway infections in patients with cystic fibrosis (CF), and it is directly associated with the morbidity and mortality connected with this disease. The ability of P. aeruginosa to establish chronic infections in CF patients...

  7. The Pseudomonas aeruginosa Pathogenicity Island PAPI-1 is transferred via a novel Type IV pilus

    Science.gov (United States)

    Pseudomonas aeruginosa is a major cause of nosocomial infections, particularly in immunocompromised patients or in individuals with cystic fibrosis. The notable ability of P. aeruginosa to inhabit a broad range of environments including humans is in part due to its large and diverse genomic repertoi...

  8. Resistance to a polyquaternium-1 lens care solution and isoelectric points of Pseudomonas aeruginosa strains

    NARCIS (Netherlands)

    Bruinsma, GM; Rustema-Abbing, M; van der Mei, HC; Lakkis, C; Busscher, HJ

    Objectives: The aim of this study was to correlate the cell surface hydrophobicity and charge of various strains of Pseudomonas aeruginosa with their resistance to a polyquaternium-1 lens care solution. Methods: The 11 P. aeruginosa strains included were isolated from eyes, contact lenses, lens

  9. Multiple roles of Pseudomonas aeruginosa TBCF10839 PilY1 in motility, transport and infection

    DEFF Research Database (Denmark)

    Bohn, Yu-Sing Tammy; Brandes, Gudrun; Rakhimova, Elza

    2009-01-01

    Polymorphonuclear neutrophils are the most important mammalian host defence cells against infections with Pseudomonas aeruginosa. Screening of a signature tagged mutagenesis library of the non-piliated P. aeruginosa strain TBCF10839 uncovered that transposon inactivation of its pilY1 gene rendered...

  10. The role of quorum sensing in the pathogenicity of the cunning aggressor Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2007-01-01

    , and, particularly, higher organisms We have focused on Pseudomonas aeruginosa, an opportunistic pathogen producing more than 30 QS-regulated virulence factors. P. aeruginosa causes several types of nosocomial infection, and lung infection in cystic fibrosis (CF) patients. We review the role of QS...

  11. Engineering PQS biosynthesis pathway for enhancement of bioelectricity production in Pseudomonas aeruginosa microbial fuel cells

    DEFF Research Database (Denmark)

    Wang, Victor Bochuan; Chua, Song-Lin; Cao, Bin

    2013-01-01

    The biosynthesis of the redox shuttle, phenazines, in Pseudomonas aeruginosa, an ubiquitous microorganism in wastewater microflora, is regulated by the 2-heptyl-3,4-dihydroxyquinoline (PQS) quorum-sensing system. However, PQS inhibits anaerobic growth of P. aeruginosa. We constructed a P. aerugin...... by genetic engineering is a suitable technique to improve power output of bioelectrochemical systems....

  12. Quorum quenching by an N-acyl-homoserine lactone acylase from Pseudomonas aeruginosa PAO1

    NARCIS (Netherlands)

    Sio, CF; Otten, LG; Cool, RH; Diggle, SP; Braun, PG; Daykin, M; Camara, M; Williams, P; Quax, WJ; Bos, R

    The virulence of the opportunistic human pathogen Pseudomonas aeruginosa PAO1 is controlled by an N-acyl-homoserine lactone (AHL)-dependent quorum-sensing system. During functional analysis of putative acylase genes in the P. aeruginosa PAO1 genome, the PA2385 gene was found to encode an acylase

  13. Within-host microevolution of Pseudomonas aeruginosa in Italian cystic fibrosis patients

    DEFF Research Database (Denmark)

    Marvig, Rasmus Lykke; Dolce, Daniela; Madsen Sommer, Lea Mette

    2015-01-01

    Chronic infection with Pseudomonas aeruginosa is a major cause of morbidity and mortality in cystic fibrosis (CF) patients, and a more complete understanding of P. aeruginosa within-host genomic evolution, transmission, and population genomics may provide a basis for improving intervention...

  14. Reconstruction of the metabolic network of Pseudomonas aeruginosa to interrogate virulence factor synthesis

    DEFF Research Database (Denmark)

    Bartell, Jennifer; Blazier, Anna S; Yen, Phillip

    2017-01-01

    to metabolism. We evaluate the complex interrelationships between growth and virulence-linked pathways using a genome-scale metabolic network reconstruction of Pseudomonas aeruginosa strain PA14 and an updated, expanded reconstruction of P. aeruginosa strain PAO1. The PA14 reconstruction accounts...

  15. Real-time monitoring of hydrogen cyanide (HCN) and ammonia (NH3) emitted by Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Neerincx, A.H.; Mandon, J.; Ingen, J. van; Arslanov, D.D.; Mouton, J.W.; Harren, F.J.; Merkus, P.J.F.M.; Cristescu, S.M.

    2015-01-01

    We present the real-time monitoring of hydrogen cyanide (HCN) production from Pseudomonas aeruginosa (P. aeruginosa) strains in vitro, using laser-based photoacoustic spectroscopy. Simultaneously, the production of ammonia (NH3) was measured, and the influence of different factors (e.g. the medium,

  16. Staphylococcus aureus Serves as an Iron Source for Pseudomonas aeruginosa during In Vivo Coculture

    OpenAIRE

    Mashburn, Lauren M.; Jett, Amy M.; Akins, Darrin R.; Whiteley, Marvin

    2005-01-01

    Pseudomonas aeruginosa is a gram-negative opportunistic human pathogen often infecting the lungs of individuals with the heritable disease cystic fibrosis and the peritoneum of individuals undergoing continuous ambulatory peritoneal dialysis. Often these infections are not caused by colonization with P. aeruginosa alone but instead by a consortium of pathogenic bacteria. Little is known about growth and persistence of P. aeruginosa in vivo, and less is known about the impact of coinfecting ba...

  17. Aerosolized bovine lactoferrin reduces neutrophils and pro-inflammatory cytokines in mouse models of Pseudomonas aeruginosa lung infections.

    Science.gov (United States)

    Valenti, Piera; Frioni, Alessandra; Rossi, Alice; Ranucci, Serena; De Fino, Ida; Cutone, Antimo; Rosa, Luigi; Bragonzi, Alessandra; Berlutti, Francesca

    2017-02-01

    Lactoferrin (Lf), an iron-chelating glycoprotein of innate immunity, produced by exocrine glands and neutrophils in infection/inflammation sites, is one of the most abundant defence molecules in airway secretions. Lf, a pleiotropic molecule, exhibits antibacterial and anti-inflammatory functions. These properties may play a relevant role in airway infections characterized by exaggerated inflammatory response, as in Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) subjects. To verify the Lf role in Pseudomonas aeruginosa lung infection, we evaluated the efficacy of aerosolized bovine Lf (bLf) in mouse models of P. aeruginosa acute and chronic lung infections. C57BL/6NCrl mice were challenged with 106 CFUs of P. aeruginosa PAO1 (acute infection) or MDR-RP73 strain (chronic infection) by intra-tracheal administration. In both acute and chronic infections, aerosolized bLf resulted in nonsignificant reduction of bacterial load but significant decrease of the neutrophil recruitment and pro-inflammatory cytokine levels. Moreover, in chronic infection the bLf-treated mice recovered body weight faster and to a higher extent than the control mice. These findings add new insights into the benefits of bLf as a mediator of general health and its potential therapeutic applications.

  18. Inhibition of Pseudomonas aeruginosa virulence: characterization of the AprA-AprI interface and species selectivity.

    Science.gov (United States)

    Bardoel, Bart W; van Kessel, Kok P M; van Strijp, Jos A G; Milder, Fin J

    2012-01-20

    Pseudomonas aeruginosa secretes the virulence factor alkaline protease (AprA) to enhance its survival. AprA cleaves one of the key microbial recognition molecules, monomeric flagellin, and thereby diminishes Toll-like receptor 5 activation. In addition, AprA degrades host proteins such as complement proteins and cytokines. P. aeruginosa encodes a highly potent inhibitor of alkaline protease (AprI) that is solely located in the periplasm where it is presumed to protect periplasmic proteins against secreted AprA. We set out to study the enzyme-inhibitor interactions in more detail in order to provide a basis for future drug development. Structural and mutational studies reveal that the conserved N-terminal residues of AprI occupy the protease active site and are essential for inhibitory activity. We constructed peptides mimicking the N-terminus of AprI; however, these were incapable of inhibiting AprA-mediated flagellin cleavage. Furthermore, we expressed and purified AprI of P. aeruginosa and the homologous (37% sequence identity) AprI of Pseudomonas syringae, which remarkably show species specificity for their cognate protease. Exchange of the first five N-terminal residues between AprI of P. syringae and P. aeruginosa did not affect the observed specificity, whereas exchange of only six residues located at the AprI surface that contacts the protease did abolish specificity. These findings are elementary steps toward the design of molecules derived from the natural inhibitor of the virulence factor AprA and their use in therapeutic applications in Pseudomonas and other Gram-negative infections. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Copper homeostasis networks in the bacterium Pseudomonas aeruginosa.

    Science.gov (United States)

    Quintana, Julia; Novoa-Aponte, Lorena; Argüello, José M

    2017-09-22

    Bacterial copper (Cu+) homeostasis enables both precise metallation of diverse cuproproteins and control of variable metal levels. To this end, protein networks mobilize Cu+ to cellular targets with remarkable specificity. However, the understanding of these processes is rather fragmented. Here, we use genome-wide transcriptomic analysis by RNA-Seq to characterize the response of Pseudomonas aeruginosa to external 0.5 mm CuSO4, a condition that did not generate pleiotropic effects. Pre-steady-state (5-min) and steady-state (2-h) Cu+ fluxes resulted in distinct transcriptome landscapes. Cells quickly responded to Cu2+ stress by slowing down metabolism. This was restored once steady state was reached. Specific Cu+ homeostasis genes were strongly regulated in both conditions. Our system-wide analysis revealed induction of three Cu+ efflux systems (a P1B-ATPase, a porin, and a resistance-nodulation-division (RND) system) and of a putative Cu+-binding periplasmic chaperone and the unusual presence of two cytoplasmic CopZ proteins. Both CopZ chaperones could bind Cu+ with high affinity. Importantly, novel transmembrane transporters probably mediating Cu+ influx were among those largely repressed upon Cu+ stress. Compartmental Cu+ levels appear independently controlled; the cytoplasmic Cu+ sensor CueR controls cytoplasmic chaperones and plasma membrane transporters, whereas CopR/S responds to periplasmic Cu+ Analysis of ΔcopR and ΔcueR mutant strains revealed a CopR regulon composed of genes involved in periplasmic Cu+ homeostasis and its putative DNA recognition sequence. In conclusion, our study establishes a system-wide model of a network of sensors/regulators, soluble chaperones, and influx/efflux transporters that control the Cu+ levels in P. aeruginosa compartments. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Phosphorylcholine Phosphatase: A Peculiar Enzyme of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Domenech

    2011-01-01

    Full Text Available Pseudomonas aeruginosa synthesizes phosphorylcholine phosphatase (PchP when grown on choline, betaine, dimethylglycine or carnitine. In the presence of Mg2+ or Zn2+, PchP catalyzes the hydrolysis of p-nitrophenylphosphate (p-NPP or phosphorylcholine (Pcho. The regulation of pchP gene expression is under the control of GbdR and NtrC; dimethylglycine is likely the metabolite directly involved in the induction of PchP. Therefore, the regulation of choline metabolism and consequently PchP synthesis may reflect an adaptive response of P. aeruginosa to environmental conditions. Bioinformatic and biochemistry studies shown that PchP contains two sites for alkylammonium compounds (AACs: one in the catalytic site near the metal ion-phosphoester pocket, and another in an inhibitory site responsible for the binding of the alkylammonium moiety. Both sites could be close to each other and interact through the residues 42E, 43E and 82YYY84. Zn2+ is better activator than Mg2+ at pH 5.0 and it is more effective at alleviating the inhibition produced by the entry of Pcho or different AACs in the inhibitory site. We postulate that Zn2+ induces at pH 5.0 a conformational change in the active center that is communicated to the inhibitory site, producing a compact or closed structure. However, at pH 7.4, this effect is not observed because to the hydrolysis of the [Zn2+L2−1L20(H2O2] complex, which causes a change from octahedral to tetrahedral in the metal coordination geometry. This enzyme is also present in P. fluorescens, P. putida, P. syringae, and other organisms. We have recently crystallized PchP and solved its structure.

  1. Structural Characterization of Novel Pseudomonas aeruginosa Type IV Pilins

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Y.; Jackson, S; Aidoo, F; Junop, M; Burrows, L

    2010-01-01

    Pseudomonas aeruginosa type IV pili, composed of PilA subunits, are used for attachment and twitching motility on surfaces. P. aeruginosa strains express one of five phylogenetically distinct PilA proteins, four of which are associated with accessory proteins that are involved either in pilin posttranslational modification or in modulation of pilus retraction dynamics. Full understanding of pilin diversity is crucial for the development of a broadly protective pilus-based vaccine. Here, we report the 1.6-{angstrom} X-ray crystal structure of an N-terminally truncated form of the novel PilA from strain Pa110594 (group V), which represents the first non-group II pilin structure solved. Although it maintains the typical T4a pilin fold, with a long N-terminal {alpha}-helix and four-stranded antiparallel {beta}-sheet connected to the C-terminus by a disulfide-bonded loop, the presence of an extra helix in the {alpha}{beta}-loop and a disulfide-bonded loop with helical character gives the structure T4b pilin characteristics. Despite the presence of T4b features, the structure of PilA from strain Pa110594 is most similar to the Neisseria gonorrhoeae pilin and is also predicted to assemble into a fiber similar to the GC pilus, based on our comparative pilus modeling. Interactions between surface-exposed areas of the pilin are suggested to contribute to pilus fiber stability. The non-synonymous sequence changes between group III and V pilins are clustered in the same surface-exposed areas, possibly having an effect on accessory protein interactions. However, based on our high-confidence model of group III PilA{sub PA14}, compensatory changes allow for maintenance of a similar shape.

  2. Genome diversity of Pseudomonas aeruginosa PAO1 laboratory strains.

    Science.gov (United States)

    Klockgether, Jens; Munder, Antje; Neugebauer, Jens; Davenport, Colin F; Stanke, Frauke; Larbig, Karen D; Heeb, Stephan; Schöck, Ulrike; Pohl, Thomas M; Wiehlmann, Lutz; Tümmler, Burkhard

    2010-02-01

    Pseudomonas aeruginosa PAO1 is the most commonly used strain for research on this ubiquitous and metabolically versatile opportunistic pathogen. Strain PAO1, a derivative of the original Australian PAO isolate, has been distributed worldwide to laboratories and strain collections. Over decades discordant phenotypes of PAO1 sublines have emerged. Taking the existing PAO1-UW genome sequence (named after the University of Washington, which led the sequencing project) as a blueprint, the genome sequences of reference strains MPAO1 and PAO1-DSM (stored at the German Collection for Microorganisms and Cell Cultures [DSMZ]) were resolved by physical mapping and deep short read sequencing-by-synthesis. MPAO1 has been the source of near-saturation libraries of transposon insertion mutants, and PAO1-DSM is identical in its SpeI-DpnI restriction map with the original isolate. The major genomic differences of MPAO1 and PAO1-DSM in comparison to PAO1-UW are the lack of a large inversion, a duplication of a mobile 12-kb prophage region carrying a distinct integrase and protein phosphatases or kinases, deletions of 3 to 1,006 bp in size, and at least 39 single-nucleotide substitutions, 17 of which affect protein sequences. The PAO1 sublines differed in their ability to cope with nutrient limitation and their virulence in an acute murine airway infection model. Subline PAO1-DSM outnumbered the two other sublines in late stationary growth phase. In conclusion, P. aeruginosa PAO1 shows an ongoing microevolution of genotype and phenotype that jeopardizes the reproducibility of research. High-throughput genome resequencing will resolve more cases and could become a proper quality control for strain collections.

  3. Pyocyanin production by Pseudomonas aeruginosa confers resistance to ionic silver.

    Science.gov (United States)

    Muller, Michael; Merrett, Neil D

    2014-09-01

    Silver in its ionic form (Ag+), but not the bulk metal (Ag0), is toxic to microbial life forms and has been used for many years in the treatment of wound infections. The prevalence of bacterial resistance to silver is considered low due to the nonspecific nature of its toxicity. However, the recent increased use of silver as an antimicrobial agent for medical, consumer, and industrial products has raised concern that widespread silver resistance may emerge. Pseudomonas aeruginosa is a common pathogen that produces pyocyanin, a redox toxin and a reductant for molecular oxygen and ferric (Fe3+) ions. The objective of this study was to determine whether pyocyanin reduces Ag+ to Ag0, which may contribute to silver resistance due to lower bioavailability of the cation. Using surface plasmon resonance spectroscopy and scanning electron microscopy, pyocyanin was confirmed to be a reductant for Ag+, forming Ag0 nanoparticles and reducing the bioavailability of free Ag+ by >95% within minutes. Similarly, a pyocyanin-producing strain of P. aeruginosa (PA14) reduced Ag+ but not a pyocyanin-deficient (ΔphzM) strain of the bacterium. Challenge of each strain with Ag+ (as AgNO3) gave MICs of 20 and 5 μg/ml for the PA14 and ΔphzM strains, respectively. Removal of pyocyanin from the medium strain PA14 was grown in or its addition to the medium that ΔphzM mutant was grown in gave MICs of 5 and 20 μg/ml, respectively. Clinical isolates demonstrated similar pyocyanin-dependent resistance to Ag+. We conclude that pseudomonal silver resistance exists independently of previously recognized intracellular mechanisms and may be more prevalent than previously considered. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  4. Crystal structure of the flavoenzyme PA4991 from Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Jacewicz, Agata; Schnell, Robert; Lindqvist, Ylva; Schneider, Gunter, E-mail: gunter.schneider@ki.se [Karolinska Institutet, S-171 77 Stockholm (Sweden)

    2016-01-22

    PA4991 is a FAD-dependent oxidoreductase from the pathogen P. aeruginosa that is essential for virulence and survival in the infected host. The structure of this enzyme, determined to 2.4 Å resolution, reveals that PA4991 belongs to the GR{sub 2} family of flavoenzymes. The locus PA4991 in Pseudomonas aeruginosa encodes an open reading frame that has been identified as essential for the virulence and/or survival of this pathogenic organism in the infected host. Here, it is shown that this gene encodes a monomeric FAD-binding protein of molecular mass 42.2 kDa. The structure of PA4991 was determined by a combination of molecular replacement using a search model generated with Rosetta and phase improvement by a low-occupancy heavy-metal derivative. PA4991 belongs to the GR{sub 2} family of FAD-dependent oxidoreductases, comprising an FAD-binding domain typical of the glutathione reductase family and a second domain dominated by an eight-stranded mixed β-sheet. Most of the protein–FAD interactions are via the FAD-binding domain, but the isoalloxazine ring is located at the domain interface and interacts with residues from both domains. A comparison with the structurally related glycine oxidase and glycerol-3-phosphate dehydrogenase shows that in spite of very low amino-acid sequence identity (<18%) several active-site residues involved in substrate binding in these enzymes are conserved in PA4991. However, enzymatic assays show that PA4991 does not display amino-acid oxidase or glycerol-3-phosphate dehydrogenase activities, suggesting that it requires different substrates for activity.

  5. METABOLIC PECULIARITIES AT EXPERIMENTAL GENERALIZED PROCESS CAUSED BY PSEUDOMONAS AERUGINOSA

    Directory of Open Access Journals (Sweden)

    Popov М. М.

    2017-06-01

    Full Text Available System of free radical oxidation is a non-specific link of most of pathologic processes formation in organism. Enzimological studies allowing the definition of both organospecific violations and the state of biological membranes are of great interest in complex approach to the estimation of structural and metabolic peculiarities of organism in conditions of inflammatory pathology. Thus the purpose of the given study is the definition of metabolic state peculiarities at experimental generalized process caused by Pseudomonas aeruginosa. According to the results of the carried out studies the activity of the processes of lipids peroxidation in myocardium of infected animals rises: the content of MDA and DC is increased in comparison with intact animals while SH-groups content and catalase activity are decreased, i.e. the oxidative stress takes place in myocardium of infected animals which leads to energy-hungry state process which is also proved by AF – enzyme activity increase which implements hydrolysis of monophosphoric esteris and LDH – enzyme of anaerobic glуcolysis. Activity of AsAT, AlAT and γ-GTP is reliably higher which proves about the activation of protein biosynthesis into tissues which is connected with accelerated enzyme synthesis under the influence of inflammation mediators, i.e. compensatory reaction activation takes place. The similar picture is found in kidneys and liver: LPO under insufficiency of AOS, power-hungry state. The level of МСВ – integrated indicator of intoxication as well as LPO products grows in blood of infected experimental animals which proves about high level of inflammatory process and organism intoxication. Increasing of protein concentration of acute phase – haptoglobulin – also proves about high level of inflammatory process. High activity of LDG (cytoplasmatic enzyme proves about cytoplasmic membranes injury. The decrease of catalase activity and level of SH-groups of blood are found in

  6. Erythromycin inhibits Pseudomonas aeruginosa-induced tumour necrosis factor-alpha production in human whole blood

    NARCIS (Netherlands)

    Schultz, M. J.; Speelman, P.; van der Poll, T.

    2001-01-01

    Erythromycin has been shown to be beneficial for panbronchiolitis, a disorder linked to infection with Pseudomonas aeruginosa. Erythromycin, but not the anti-Pseudomonas antibiotics imipenem, ceftazidime, gentamicin and ciprofloxacin, caused a dose-dependent decrease in the production of tumour

  7. Regulation of pqs quorum sensing via catabolite repression control in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Zhang, Lianbo; Gao, Qingguo; Chen, Wanying

    2013-01-01

    that the Pseudomonas aeruginosa catabolite repression control protein regulates the Pseudomonas quinolone signal quorum sensing, which further controls synthesis of virulence factor pyocyanin, biofilm formation and survival during infection models. Our study suggests that deregulation of the catabolite repression by P...

  8. The pseudomonas quinolone signal (PQS balances life and death in Pseudomonas aeruginosa populations.

    Directory of Open Access Journals (Sweden)

    Susanne Häussler

    Full Text Available When environmental conditions deteriorate and become inhospitable, generic survival strategies for populations of bacteria may be to enter a dormant state that slows down metabolism, to develop a general tolerance to hostile parameters that characterize the habitat, and to impose a regime to eliminate damaged members. Here, we provide evidence that the pseudomonas quinolone signal (PQS mediates induction of all of these phenotypes. For individual cells, PQS, an interbacterial signaling molecule of Pseudomonas aeruginosa, has both deleterious and beneficial activities: on the one hand, it acts as a pro-oxidant and sensitizes the bacteria towards oxidative and other stresses and, on the other, it efficiently induces a protective anti-oxidative stress response. We propose that this dual function fragments populations into less and more stress tolerant members which respond differentially to developing stresses in deteriorating habitats. This suggests that a little poison may be generically beneficial to populations, in promoting survival of the fittest, and in contributing to bacterial multi-cellular behavior. It further identifies PQS as an essential mediator of the shaping of the population structure of Pseudomonas and of its response to and survival in hostile environmental conditions.

  9. Identification of outer membrane Porin D as a vitronectin-binding factor in cystic fibrosis clinical isolates of Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Paulsson, Magnus; Singh, Birendra; Al-Jubair, Tamim

    2015-01-01

    BACKGROUND: Pseudomonas aeruginosa is a pathogen that frequently colonizes patients with cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD). Several pathogens are known to bind vitronectin to increase their virulence. Vitronectin has been shown to enhance P. aeruginosa adhesion...

  10. Dermal Wound Transcriptomic Responses to Infection with Pseudomonas aeruginosa versus Klebsiella pneumoniae in a Rabbit Ear Wound Model

    Science.gov (United States)

    2014-05-02

    Dermal wound transcriptomic responses to Infection with Pseudomonas aeruginosa versus Klebsiella pneumoniae in a rabbit ear wound model Kai P Leung Pt...with Klebsiella pneumoniae (Kp.) or Pseudomonas aeruginosa (P.o.) would indicate host responses associated with the worse healing of P.o. than Kp...responses to injection with Pseudomonas aeruginosa versus Klebsiella pneumoniae in a rabbit ear wound model 5a. CONTRACT NUMBER 5b. GRANT NUMBER

  11. Characterization of the Pseudomonas aeruginosa metalloendopeptidase, Mep72, a member of the Vfr regulon.

    Science.gov (United States)

    Balyimez, Aysegul; Colmer-Hamood, Jane A; San Francisco, Michael; Hamood, Abdul N

    2013-11-27

    Pseudomonas aeruginosa Vfr (the virulence factor regulator) enhances P. aeruginosa virulence by positively regulating the expression of numerous virulence genes. A previous microarray analysis identified numerous genes positively regulated by Vfr in strain PAK, including the yet uncharacterized PA2782 and PA2783. In this study, we report the detailed characterization of PA2783 in the P. aeruginosa strain PAO1. RT-PCR analysis confirmed that PA2782-PA2783 constitute an operon. A mutation in vfr significantly reduced the expression of both genes. The predicted protein encoded by PA2783 contains a typical leader peptide at its amino terminus end as well as metalloendopeptidase and carbohydrate binding motifs at its amino terminus and carboxy terminus regions, respectively. An in-frame PA2783::phoA fusion encoded a hybrid protein that was exported to the periplasmic space of Escherichia coli and P. aeruginosa. In PAO1, the proteolytic activity of the PA2783-encoded protein was masked by other P. aeruginosa extracellular proteases but an E. coli strain carrying a PA2783 recombinant plasmid produced considerable proteolytic activity. The outer membrane fraction of an E. coli strain in which PA2783 was overexpressed contained specific endopeptidase activity. In the presence of cAMP, purified recombinant Vfr (rVfr) bound to a 98-bp fragment within the PA2782-PA2783 upstream region that carries a putative Vfr consensus sequence. Through a series of electrophoretic mobility shift assays, we localized rVfr binding to a 33-bp fragment that contains part of the Vfr consensus sequence and a 5-bp imperfect (3/5) inverted repeat at its 3' and 5' ends (TGGCG-N22-CGCTG). Deletion of either repeat eliminated Vfr binding. PA2782 and PA2783 constitute an operon whose transcription is positively regulated by Vfr. The expression of PA2783 throughout the growth cycle of P. aeruginosa follows a unique pattern. PA2783 codes for a secreted metalloendopeptidase, which we named Mep72. Mep72

  12. Long-distance delivery of bacterial virulence factors by Pseudomonas aeruginosa outer membrane vesicles.

    Directory of Open Access Journals (Sweden)

    Jennifer M Bomberger

    2009-04-01

    Full Text Available Bacteria use a variety of secreted virulence factors to manipulate host cells, thereby causing significant morbidity and mortality. We report a mechanism for the long-distance delivery of multiple bacterial virulence factors, simultaneously and directly into the host cell cytoplasm, thus obviating the need for direct interaction of the pathogen with the host cell to cause cytotoxicity. We show that outer membrane-derived vesicles (OMV secreted by the opportunistic human pathogen Pseudomonas aeruginosa deliver multiple virulence factors, including beta-lactamase, alkaline phosphatase, hemolytic phospholipase C, and Cif, directly into the host cytoplasm via fusion of OMV with lipid rafts in the host plasma membrane. These virulence factors enter the cytoplasm of the host cell via N-WASP-mediated actin trafficking, where they rapidly distribute to specific subcellular locations to affect host cell biology. We propose that secreted virulence factors are not released individually as naked proteins into the surrounding milieu where they may randomly contact the surface of the host cell, but instead bacterial derived OMV deliver multiple virulence factors simultaneously and directly into the host cell cytoplasm in a coordinated manner.

  13. Feeding behaviour of Caenorhabditis elegans is an indicator of Pseudomonas aeruginosa PAO1 virulence

    Directory of Open Access Journals (Sweden)

    Shawn Lewenza

    2014-08-01

    Full Text Available Caenorhabditis elegans is commonly used as an infection model for pathogenesis studies in Pseudomonas aeruginosa. The standard virulence assays rely on the slow and fast killing or paralysis of nematodes but here we developed a behaviour assay to monitor the preferred bacterial food sources of C. elegans. We monitored the food preferences of nematodes fed the wild type PAO1 and mutants in the type III secretion (T3S system, which is a conserved mechanism to inject secreted effectors into the host cell cytosol. A ΔexsEΔpscD mutant defective for type III secretion served as a preferred food source, while an ΔexsE mutant that overexpresses the T3S effectors was avoided. Both food sources were ingested and observed in the gastrointestinal tract. Using the slow killing assay, we showed that the ΔexsEΔpscD had reduced virulence and thus confirmed that preferred food sources are less virulent than the wild type. Next we developed a high throughput feeding behaviour assay with 48 possible food colonies in order to screen a transposon mutant library and identify potential virulence genes. C. elegans identified and consumed preferred food colonies from a grid of 48 choices. The mutants identified as preferred food sources included known virulence genes, as well as novel genes not identified in previous C. elegans infection studies. Slow killing assays were performed and confirmed that several preferred food sources also showed reduced virulence. We propose that C. elegans feeding behaviour can be used as a sensitive indicator of virulence for P. aeruginosa PAO1.

  14. Polysaccharides serve as scaffold of biofilms formed by mucoid Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Yang, Liang; Hengzhuang, Wang; Wu, Hong

    2012-01-01

    Chronic lung infection by mucoid Pseudomonas aeruginosa is one of the major pathologic features in patients with cystic fibrosis. Mucoid P. aeruginosa is notorious for its biofilm forming capability and resistance to immune attacks. In this study, the roles of extracellular polymeric substances...... from biofilms formed by mucoid P. aeruginosa were investigated. Alginate is not an essential structure component for mucoid P. aeruginosa biofilms. Genetic studies revealed that Pel and Psl polysaccharides serve as essential scaffold and mediate macrocolony formation in mucoid P. aeruginosa biofilms....... The Psl polysaccharide is more important than Pel polysaccharide in mucoid P. aeruginosa biofilm structure maintenance and phagocytosis resistance. The polysaccharides were further found to protect mucoid P. aeruginosa strain from host immune clearance in a mouse model of acute lung infection....

  15. Identification of Five Structurally Unrelated Quorum-Sensing Inhibitors of Pseudomonas aeruginosa from a Natural-Derivative Database

    DEFF Research Database (Denmark)

    Tan, Sean Yang-Yi; Chua, Song-Lin; Chen, Yicai

    2013-01-01

    (QSIs), have been shown to effectively block QS and subsequently attenuate the virulence of Pseudomonas aeruginosa, as well as increasing its susceptibility to both antibiotics and the immune system. In this study, a structure-based virtual screening (SB-VS) approach was used for the discovery of novel...... synthetases. G1 was also able to reduce extracellular DNA release and inhibited the secretion of the virulence factor, elastase, whose expression is regulated by LasR. These results demonstrate the utility of SB-VS for the discovery of target-specific QSIs....

  16. Severe Hyponatremia due to Levofloxacin Treatment for Pseudomonas aeruginosa Community-Acquired Pneumonia in a Patient with Oropharyngeal Cancer

    Directory of Open Access Journals (Sweden)

    Mihaela Mocan

    2016-01-01

    Full Text Available Hyponatremia (serum Na levels of <135 mEq/L is the most common electrolyte imbalance encountered in clinical practice, affecting up to 15–28% of hospitalized patients. This case report refers to a middle-aged man with severe hyponatremia due to Syndrome of Inappropriate Antidiuretic Hormone Secretion related to four possible etiological factors: glossopharyngeal squamous cell carcinoma, cisplatin treatment, right basal pneumonia with Pseudomonas aeruginosa, and the treatment with Levofloxacin. This case report discusses a rare complication of common conditions and of a common treatment. To our knowledge this is the first case of hyponatremia related to Levofloxacin and the second related to fluoroquinolones.

  17. Mucoid conversion of Pseudomonas aeruginosa by hydrogen peroxide: a mechanism for virulence activation in the cystic fibrosis lung

    DEFF Research Database (Denmark)

    Mathee, K; Ciofu, O; Sternberg, C

    1999-01-01

    The leading cause of mortality in patients with cystic fibrosis (CF) is respiratory failure due in large part to chronic lung infection with Pseudomonas aeruginosa strains that undergo mucoid conversion, display a biofilm mode of growth in vivo and resist the infiltration of polymorphonuclear...... of alginate, (ii) exhibited no detectable differences in growth rate, (iii) showed an unaltered LPS profile, (iv) were approximately 72% reduced in the amount of inducible-beta-lactamase and (v) secreted little or no LasA protease and only showed 44% elastase activity. A characteristic approximately 54 k...

  18. Mucoid conversion of Pseudomonas aeruginosa by hydrogen peroxide: a mechanism for virulence activation in the cystic fibrosis lung

    DEFF Research Database (Denmark)

    Mathee, Kalai; Ciofu, Oana; Sternberg, Claus

    1999-01-01

    The leading cause of mortality in patients with cystic fibrosis (CF) is respiratory failure due in large part to chronic lung infection with Pseudomonas aeruginosa strains that undergo mucoid conversion, display a biofilm mode of growth in vivo and resist the infiltration of polymorphonuclear......) exhibited no detectable differences in growth rate, (iii) showed an unaltered LPS profile, (iv) were similar to 72% reduced in the amount of inducible-beta-lactamase and (v) secreted little or Department of Clinical no LasA protease and only showed 44% elastase activity. A characteristic similar to 54 k...

  19. Epoxide-Mediated CifR Repression of cif Gene Expression Utilizes Two Binding Sites in Pseudomonas aeruginosa

    OpenAIRE

    Ballok, Alicia E.; Bahl, Christopher D.; Dolben, Emily L.; Lindsay, Allia K.; St. Laurent, Jessica D.; Hogan, Deborah A.; Madden, Dean R.; O'Toole, George A.

    2012-01-01

    Pseudomonas aeruginosa secretes an epoxide hydrolase virulence factor that reduces the apical membrane expression of ABC transporters such as the cystic fibrosis transmembrane conductance regulator (CFTR). This virulence factor, named CFTR inhibitory factor (Cif), is regulated by a TetR-family, epoxide-responsive repressor known as CifR via direct binding and repression. We identified two sites of CifR binding in the intergenic space between cifR and morB, the first gene in the operon contain...

  20. [Cervical lymphoadenopathy due to Pseudomonas aeruginosa following mesotherapy].

    Science.gov (United States)

    Shaladi, Ali Muftah; Crestani, Francesco; Bocchi, Anna; Saltari, Maria Rita; Piva, Bruno; Tartari, Stefano

    2009-09-01

    Mesotherapy is a treatment method devised for controlling several diseases by means of subcutaneous microinjections given at or around the affected areas at short time intervals. It is used to treat a variety of medical conditions, amongst which all orthopaedic diseases and rheumatic pain. Mesotherapy is especially indicated for neck pain. The mechanism of action is twofold: a pharmacological effect due to the drug administered, and a reflexogenic effect, the skin containing many nerve endings that are sensitive to the mechanical action of the needle. Although this therapy is safe, like any other medical intervention it cannot be considered free of complications that may occur, such as allergies, haematomas, bruising, wheals, granulomas and telangiectasias. Infective complications are also possible, due to pathogenic bacteria that are inoculated through contamination of products, of the materials used for the procedure or even from germs on the skin. We present the case of a patient who had cervical lymphadenopathy due to Pseudomonas aeruginosa after mesotherapy treatment for neck pain.

  1. Ginger Extract Inhibits Biofilm Formation by Pseudomonas aeruginosa PA14

    Science.gov (United States)

    Kim, Han-Shin; Park, Hee-Deung

    2013-01-01

    Bacterial biofilm formation can cause serious problems in clinical and industrial settings, which drives the development or screening of biofilm inhibitors. Some biofilm inhibitors have been screened from natural products or modified from natural compounds. Ginger has been used as a medicinal herb to treat infectious diseases for thousands of years, which leads to the hypothesis that it may contain chemicals inhibiting biofilm formation. To test this hypothesis, we evaluated ginger’s ability to inhibit Pseudomonas aeruginosa PA14 biofilm formation. A static biofilm assay demonstrated that biofilm development was reduced by 39–56% when ginger extract was added to the culture. In addition, various phenotypes were altered after ginger addition of PA14. Ginger extract decreased production of extracellular polymeric substances. This finding was confirmed by chemical analysis and confocal laser scanning microscopy. Furthermore, ginger extract formed noticeably less rugose colonies on agar plates containing Congo red and facilitated swarming motility on soft agar plates. The inhibition of biofilm formation and the altered phenotypes appear to be linked to a reduced level of a second messenger, bis-(3′-5′)-cyclic dimeric guanosine monophosphate. Importantly, ginger extract inhibited biofilm formation in both Gram-positive and Gram-negative bacteria. Also, surface biofilm cells formed with ginger extract detached more easily with surfactant than did those without ginger extract. Taken together, these findings provide a foundation for the possible discovery of a broad spectrum biofilm inhibitor. PMID:24086697

  2. Biosurfactant Production by Pseudomonas aeruginosa from Renewable Resources.

    Science.gov (United States)

    Thavasi, R; Subramanyam Nambaru, V R M; Jayalakshmi, S; Balasubramanian, T; Banat, Ibrahim M

    2011-01-01

    This study deals with production and characterization of biosurfactant from renewable resources by Pseudomonas aeruginosa. Biosurfactant production was carried out in 3L fermentor using waste motor lubricant oil and peanut oil cake. Maximum biomass (11.6 mg/ml) and biosurfactant production (8.6 mg/ml) occurred with peanut oil cake at 120 and 132 h respectively. Characterization of the biosurfactant revealed that, it is a lipopeptide with chemical composition of protein (50.2%) and lipid (49.8%). The biosurfactant (1 mg/ml) was able to emulsify waste motor lubricant oil, crude oil, peanut oil, kerosene, diesel, xylene, naphthalene and anthracene, comparatively the emulsification activity was higher than the activity found with Triton X-100 (1 mg/ml). Results obtained in the present study showed the possibility of biosurfactant production using renewable, relatively inexpensive and easily available resources. Emulsification activity found with the biosurfactant against different hydrocarbons showed its possible application in bioremediation of environments polluted with various hydrocarbons.

  3. Pa0148 from Pseudomonas aeruginosa Catalyzes the Deamination of Adenine

    Energy Technology Data Exchange (ETDEWEB)

    A Goble; Z Zhang; J Sauder; S Burley; S Swaminathan; F Raushel

    2011-12-31

    Four proteins from NCBI cog1816, previously annotated as adenosine deaminases, have been subjected to structural and functional characterization. Pa0148 (Pseudomonas aeruginosa PAO1), AAur1117 (Arthrobacter aurescens TC1), Sgx9403e, and Sgx9403g have been purified and their substrate profiles determined. Adenosine is not a substrate for any of these enzymes. All of these proteins will deaminate adenine to produce hypoxanthine with k{sub cat}/K{sub m} values that exceed 10{sup 5} M{sup -1} s{sup -1}. These enzymes will also accept 6-chloropurine, 6-methoxypurine, N-6-methyladenine, and 2,6-diaminopurine as alternate substrates. X-ray structures of Pa0148 and AAur1117 have been determined and reveal nearly identical distorted ({beta}/{alpha}){sub 8} barrels with a single zinc ion that is characteristic of members of the amidohydrolase superfamily. Structures of Pa0148 with adenine, 6-chloropurine, and hypoxanthine were also determined, thereby permitting identification of the residues responsible for coordinating the substrate and product.

  4. Production and characterization of rhamnolipids from Pseudomonas aeruginosa san ai

    Directory of Open Access Journals (Sweden)

    Rikalovic Milena G.

    2012-01-01

    Full Text Available Production and characterization of rhamnolipid biosurfactant obtained by strain Pseudomonas aeruginosa san ai was investigated. With regard to carbon and nitrogen source several media were tested to enhance production of rhamnolipids. Phosphate-limited proteose peptone-ammonium salt (PPAS medium supplemented with sun flower oil as a source of carbon and mineral ammonium chloride and peptone as a nitrogen source greatly improved rhamnolipid production, from 0.15 on basic PPAS (C/N ratio 4.0, to 3 g L-1, on optimized PPAS medium (C/N ratio 7.7. Response surface methodology analysis was used for testing effect of three factors: temperature, concentration of carbon and nitrogen source (w/w, in optimized PPAS medium on rhamnolipid production. Isolated rhamnolipids were characterized by IR and ESI-MS. IR spectra confirmed that isolated compound corresponds to rhamnolipid structure, whereas MS indicated that isolated preparation is a mixture of mono-rhamno-mono-lipidic, mono-rhamno-di-lipidic- and dirhamno- di-lipidic congeners.

  5. PA0148 from Pseudomonas aeruginosa Catalyzes the Deamination of Adenine

    Energy Technology Data Exchange (ETDEWEB)

    Goble, A.M.; Swaminathan, S.; Zhang, Z.; Sauder, J. M.; Burley, S. K.; Raushel, F. M.

    2011-08-02

    Four proteins from NCBI cog1816, previously annotated as adenosine deaminases, have been subjected to structural and functional characterization. Pa0148 (Pseudomonas aeruginosa PAO1), AAur1117 (Arthrobacter aurescens TC1), Sgx9403e, and Sgx9403g have been purified and their substrate profiles determined. Adenosine is not a substrate for any of these enzymes. All of these proteins will deaminate adenine to produce hypoxanthine with k{sub cat}/K{sub m} values that exceed 10{sup 5} M{sup -1} s{sup -1}. These enzymes will also accept 6-chloropurine, 6-methoxypurine, N-6-methyladenine, and 2,6-diaminopurine as alternate substrates. X-ray structures of Pa0148 and AAur1117 have been determined and reveal nearly identical distorted ({beta}/{alpha}){sub 8} barrels with a single zinc ion that is characteristic of members of the amidohydrolase superfamily. Structures of Pa0148 with adenine, 6-chloropurine, and hypoxanthine were also determined, thereby permitting identification of the residues responsible for coordinating the substrate and product.

  6. Novel polymeric nanoparticles targeting the lipopolysaccharides of Pseudomonas aeruginosa.

    Science.gov (United States)

    Long, Y; Li, Z; Bi, Q; Deng, C; Chen, Z; Bhattachayya, S; Li, C

    2016-04-11

    Considering outburst of various infectious diseases globally, nanoparticle assisted targeted drug delivery has emerged as a promising strategy that can enhance the therapeutic efficacy and minimize the undesirable side effects of an antimicrobial agents. Molecular imprinting is a newly developed strategy that can synthesize a drug carrier with highly stable ligand-like 'cavity', may serve as a new platform of ligand-free targeted drug delivery systems. In this study, we use the amphiphilic lipopolysaccharides, derived from Pseudomonas aeruginosa as imprinting template and obtained an evenly distributed sub-40 nm polymeric nanoparticles by using inverse emulsion method. These molecularly imprinted nanoparticles (MIPNPs) showed specific binding to the lipopolysaccharide as determined by fluorescence polarization and microscale thermophoresis. MIPNPs showed selective recognition of target bacteria as detected by flow cytometry. Additionally, MIPNPs exhibited the in vivo targeting capabilities in both the keratitis model and meningitis model. Moreover, the photosensitizer methylene blue-loaded MIPNPs presented significantly strong inhibition of bacterial Growth, compared to non-imprinted controls for in vitro model of the photodynamic therapy. Our study shows an attempt to design a magic bullet by molecular imprinting that may provide a novel approach to generate synthetic carrier for targeting pathogen and treatment for a variety of infectious human diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Alkaline protease contributes to pyocyanin production in Pseudomonas aeruginosa.

    Science.gov (United States)

    Iiyama, Kazuhiro; Takahashi, Eigo; Lee, Jae Man; Mon, Hiroaki; Morishita, Mai; Kusakabe, Takahiro; Yasunaga-Aoki, Chisa

    2017-04-01

    The role of the alkaline protease (AprA) in pyocyanin production in Pseudomonas aeruginosa was investigated. AprA was overproduced when a plasmid carrying the aprA gene was introduced to an aprA-deletion mutant strain, EG03; thus, aprA-complemented EG03 was used as an overproducing strain. The complemented strain produced higher pyocyanin than the mutant strain in all commercially available media evaluated. Particularly, pyocyanin production was higher in the complemented than in the parental strain in brain-heart infusion and tryptic soy broths. These results suggested that protein degradation products by AprA were utilized for pyocyanin production. Protein-rich media were used in subsequent validation studies. Similar results were obtained when the basal medium was supplemented with casein or skim milk as the sole organic nitrogen source. However, gelatin failed to induce abundant pyocyanin production in the complemented strain, despite the presence of protein degradation products by AprA as assessed by SDS-PAGE. Thus, gelatin degradation products may not be suitable for pyocyanin synthesis. In conclusion, AprA could contribute to pyocyanin production in the presence of several proteins or peptides. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. The cost of multiple drug resistance in Pseudomonas aeruginosa.

    Science.gov (United States)

    Ward, H; Perron, G G; Maclean, R C

    2009-05-01

    The spread of bacterial antibiotic resistance mutations is thought to be constrained by their pleiotropic fitness costs. Here we investigate the fitness costs of resistance in the context of the evolution of multiple drug resistance (MDR), by measuring the cost of acquiring streptomycin resistance mutations (StrepR) in independent strains of the bacterium Pseudomonas aeruginosa carrying different rifampicin resistance (RifR) mutations. In the absence of antibiotics, StrepR mutations are associated with similar fitness costs in different RifR genetic backgrounds. The cost of StrepR mutations is greater in a rifampicin-sensitive (RifS) background, directly demonstrating antagonistic epistasis between resistance mutations. In the presence of rifampicin, StrepR mutations have contrasting effects in different RifR backgrounds: StrepR mutations have no detectable costs in some RifR backgrounds and massive fitness costs in others. Our results clearly demonstrate the importance of epistasis and genotype-by-environment interactions for the evolution of MDR.

  9. Effect of SPLUNC1 protein on the Pseudomonas aeruginosa and Epstein-Barr virus.

    Science.gov (United States)

    Zhou, Hou-De; Li, Xiao-Ling; Li, Gui-Yuan; Zhou, Ming; Liu, Hua-Ying; Yang, Yi-Xing; Deng, Tan; Ma, Jian; Sheng, Shou-Rong

    2008-02-01

    Short palate, lung and nasal epithelium clone 1 (SPLUNC1) gene coded a secreted protein found at the surface of nasopharyngeal epithelium, which may be an innate immunity defensive molecular and a risk factor for nasopharyngeal carcinoma (NPC). Here, we observed the effects of SPLUNC1 on the Gram negative bacteria Pseudomonas aeruginosa, evaluated the ability of SPLUNC1 protein binding to lipopolysaccharide. To observe the effect of SPLUNC1 protein on Epstein-Barr virus (EBV), we raised three EBV-transformed B-lymphocyte lines and treated the cells by SPLUNC1 protein; cellular disruption, apoptosis, EBV DNA content, and viral oncogene expression were analyzed. We found that SPLUNC1 protein can bind to bacterial lipopolysaccharide, inhibit the growth of P. aeruginosa, enhance the disruption and apoptosis of EBV-infected B-lymphocytes, downregulate protein expression of EBV latent membrane protein 1, while upregulate protein expression of EBV envelope glycoprotein gp350/220. The total EBV DNA in the culture medium was decreased significantly after 7 days of treatment by SPLUNC1. This study shows that SPLUNC1 not only has the role of antibacteria and antivirus, but also inhibits the potential oncogenicity of EBV in respiratory epithelium.

  10. Stationary phase-specific virulence factor overproduction by a lasR mutant of Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Matthew T Cabeen

    Full Text Available Secreted virulence factors of the human pathogen Pseudomonas aeruginosa are often under quorum sensing control. Cells lacking the quorum-sensing regulator LasR show reduced virulence factor production under typical laboratory conditions and are hypo-virulent in short-term animal infection models, yet lasR mutants are frequently associated with long-term infection in cystic fibrosis patients. Here, I show that in stationary-phase or slow-growth conditions, lasR cells continuously and strongly produce the important virulence factor pyocyanin while wild-type cells do not. Pyocyanin overproduction by lasR cells is permitted by loss of repression by RsaL, a LasR-dependent negative regulator. lasR cells also contribute pyocyanin in mixed cultures, even under "cheating" conditions where they depend on their wild-type neighbors for nutrients. Finally, some clinical P. aeruginosa isolates with lasR mutations can overproduce pyocyanin in the laboratory. These results imply that slow-growing clinical populations of lasR cells in chronic infections may contribute to virulence by producing pyocyanin under conditions where lasR⁺ cells do not.

  11. Stationary Phase-Specific Virulence Factor Overproduction by a lasR Mutant of Pseudomonas aeruginosa

    Science.gov (United States)

    Cabeen, Matthew T.

    2014-01-01

    Secreted virulence factors of the human pathogen Pseudomonas aeruginosa are often under quorum sensing control. Cells lacking the quorum-sensing regulator LasR show reduced virulence factor production under typical laboratory conditions and are hypo-virulent in short-term animal infection models, yet lasR mutants are frequently associated with long-term infection in cystic fibrosis patients. Here, I show that in stationary-phase or slow-growth conditions, lasR cells continuously and strongly produce the important virulence factor pyocyanin while wild-type cells do not. Pyocyanin overproduction by lasR cells is permitted by loss of repression by RsaL, a LasR-dependent negative regulator. lasR cells also contribute pyocyanin in mixed cultures, even under “cheating” conditions where they depend on their wild-type neighbors for nutrients. Finally, some clinical P. aeruginosa isolates with lasR mutations can overproduce pyocyanin in the laboratory. These results imply that slow-growing clinical populations of lasR cells in chronic infections may contribute to virulence by producing pyocyanin under conditions where lasR+ cells do not. PMID:24533146

  12. Immunochemical Determination of Pyocyanin and 1-Hydroxyphenazine as Potential Biomarkers of Pseudomonas aeruginosa Infections.

    Science.gov (United States)

    Pastells, Carme; Pascual, Nuria; Sanchez-Baeza, Francisco; Marco, M-Pilar

    2016-02-02

    A novel immunochemical approach to diagnose Pseudomonas aeruginosa infections is reported, which is based on the quantification of relevant and specific virulence factors secreted by this microorganism. Specific antibodies have been raised using hapten PC1 (a 1:1 mixture of 9-hydroxy- and 6-hydroxy-phenazine-2-carobxylic acids), designed to recognize 1-hydroxyphenazine (1-OHphz), which is the main metabolite of pyocyanin (PYO). PYO is one of the most important virulence factors produced by nearly all P. aeruginosa strains, and other species do not produce this factor. With these antibodies, an immunochemical analytical procedure able to quantify both 1-OHphz and PYO in complex clinical samples has been developed. 1-OHphz can be directly measured in solubilized sputum samples diluted 20 times with the assay buffer. Quantification of PYO is accomplished after conversion to 1-OHphz in just 20 min under basic conditions. A LOD of 0.60 ± 0.01 nM (4.80 ± 0.08 nmol kg(-1) sputum) is reached for both biomarker targets under the conditions established, a value that is much below the reported concentrations on sputum samples obtained from infected patients (up to 100 μM). The assay is robust, reproducible, accurate, can be run in about 2 h, and many samples can be measured simultaneously. The present reported assay could represent a significant improvement in the diagnosis of infectious diseases caused by this pathogen.

  13. [Incidence of alginate-coding gene in carbapenem-resistant Pseudomonas aeruginosa strains].

    Science.gov (United States)

    Bogiel, Tomasz; Kwiecińska-Piróg, Joanna; Kozuszko, Sylwia; Gospodarek, Eugenia

    2011-01-01

    Pseudomonas aeruginosa rods are one of the most common isolated opportunistic nosocomial pathogens. Strains usually are capable to secret a capsule-like polysaccharide called alginate important for evasion of host defenses, especially during chronic pulmonary disease of patients with cystic fibrosis. Most genes for alginate biosynthesis and lysis are encoded by the operon. The aim of our study was to evaluate the incidence of algD sequence, generally use for alginate-coding gene detection, in 120 P. aeruginosa strains resistant to carbapenems. All isolates were obtained in the Department of Clinical Microbiology University Hospital no. 1 of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Toruń. Examined strains demonstrated resistance to carbenicillin (90,0%), ticarcillin (89,2%) and ticarcillin clavulanate (86,7%). All strains were susceptible to colistin. The majority of examined strains was susceptible to ceftazidime and cefepime (40,8% each) and norfloxacin (37,5%). Presence of algD gene - noted in 112 (93,3%) strains proves that not every strain is capable to produce alginate. It was also found out that differences in algD genes incidence in case of different clinical material that strains were isolated from were not statistically important.

  14. Pseudomonas aeruginosa sabotages the generation of host proresolving lipid mediators

    Energy Technology Data Exchange (ETDEWEB)

    Flitter, Becca A.; Hvorecny, Kelli L.; Ono, Emiko; Eddens, Taylor; Yang, Jun; Kwak, Daniel H.; Bahl, Christopher D.; Hampton, Thomas H.; Morisseau, Christophe; Hammock, Bruce D.; Liu, Xinyu; Lee, Janet S.; Kolls, Jay K.; Levy, Bruce D.; Madden, Dean R.; Bomberger, Jennifer M.

    2016-12-15

    Recurrent Pseudomonas aeruginosa infections coupled with robust, damaging neutrophilic inflammation characterize the chronic lung disease cystic fibrosis (CF). The proresolving lipid mediator, 15-epi lipoxin A4 (15-epi LXA4), plays a critical role in limiting neutrophil activation and tissue inflammation, thus promoting the return to tissue homeostasis. Here, we show that a secreted P. aeruginosa epoxide hydrolase, cystic fibrosis transmembrane conductance regulator inhibitory factor (Cif), can disrupt 15-epi LXA4 transcellular biosynthesis and function. In the airway, 15-epi LXA4 production is stimulated by the epithelial-derived eicosanoid 14,15-epoxyeicosatrienoic acid (14,15-EET). Cif sabotages the production of 15-epi LXA4 by rapidly hydrolyzing 14,15-EET into its cognate diol, eliminating a proresolving signal that potently suppresses IL-8–driven neutrophil transepithelial migration in vitro. Retrospective analyses of samples from patients with CF supported the translational relevance of these preclinical findings. Elevated levels of Cif in bronchoalveolar lavage fluid were correlated with lower levels of 15-epi LXA4, increased IL-8 concentrations, and impaired lung function. Together, these findings provide structural, biochemical, and immunological evidence that the bacterial epoxide hydrolase Cif disrupts resolution pathways during bacterial lung infections. The data also suggest that Cif contributes to sustained pulmonary inflammation and associated loss of lung function in patients with CF.

  15. Pseudomonas aeruginosa RhlR is required to neutralize the cellular immune response in a Drosophila melanogaster oral infection model

    Science.gov (United States)

    Limmer, Stefanie; Haller, Samantha; Drenkard, Eliana; Lee, Janice; Yu, Shen; Kocks, Christine; Ausubel, Frederick M.; Ferrandon, Dominique

    2011-01-01

    An in-depth mechanistic understanding of microbial infection necessitates a molecular dissection of host–pathogen relationships. Both Drosophila melanogaster and Pseudomonas aeruginosa have been intensively studied. Here, we analyze the infection of D. melanogaster by P. aeruginosa by using mutants in both host and pathogen. We show that orally ingested P. aeruginosa crosses the intestinal barrier and then proliferates in the hemolymph, thereby causing the infected flies to die of bacteremia. Host defenses against ingested P. aeruginosa included an immune deficiency (IMD) response in the intestinal epithelium, systemic Toll and IMD pathway responses, and a cellular immune response controlling bacteria in the hemocoel. Although the observed cellular and intestinal immune responses appeared to act throughout the course of the infection, there was a late onset of the systemic IMD and Toll responses. In this oral infection model, P. aeruginosa PA14 did not require its type III secretion system or other well-studied virulence factors such as the two-component response regulator GacA or the protease AprA for virulence. In contrast, the quorum-sensing transcription factor RhlR, but surprisingly not LasR, played a key role in counteracting the cellular immune response against PA14, possibly at an early stage when only a few bacteria are present in the hemocoel. These results illustrate the power of studying infection from the dual perspective of host and pathogen by revealing that RhlR plays a more complex role during pathogenesis than previously appreciated. PMID:21987808

  16. A Genetic Screen Reveals Novel Targets to Render Pseudomonas aeruginosa Sensitive to Lysozyme and Cell Wall-Targeting Antibiotics.

    Science.gov (United States)

    Lee, Kang-Mu; Lee, Keehoon; Go, Junhyeok; Park, In Ho; Shin, Jeon-Soo; Choi, Jae Young; Kim, Hyun Jik; Yoon, Sang Sun

    2017-01-01

    Pseudomonas aeruginosa is capable of establishing airway infections. Human airway mucus contains a large amount of lysozyme, which hydrolyzes bacterial cell walls. P. aeruginosa, however, is known to be resistant to lysozyme. Here, we performed a genetic screen using a mutant library of PAO1, a prototype P. aeruginosa strain, and identified two mutants (ΔbamB and ΔfabY) that exhibited decrease in survival after lysozyme treatment. The bamB and fabY genes encode an outer membrane assembly protein and a fatty acid synthesis enzyme, respectively. These two mutants displayed retarded growth in the airway mucus secretion (AMS). In addition, these mutants exhibited reduced virulence and compromised survival fitness in two different in vivo infection models. The mutants also showed susceptibility to several antibiotics. Especially, ΔbamB mutant was very sensitive to vancomycin, ampicillin, and ceftazidime that target cell wall synthesis. The ΔfabY displayed compromised membrane integrity. In conclusion, this study uncovered a common aspect of two different P. aeruginosa mutants with pleiotropic phenotypes, and suggests that BamB and FabY could be novel potential drug targets for the treatment of P. aeruginosa infection.

  17. Biosorpsi Logam Zn Pada Limbah Sintetik Menggunakan Biomassa Campuran Pseudomonas aeruginosa dan Pseudomonas sp

    Directory of Open Access Journals (Sweden)

    Hidayati Hidayati

    2013-12-01

    Full Text Available Zinc is one of the heavy metals that could be harmful for environment. This metal usually arises from industrial activities. Biosorption of zinc in synthetic waste was conducted using biomass mixture of Pseudomonas aeruginosa and Pseudomonas sp. This research aims to determine the zinc adsorption capacity of the biomass in synthetic waste water. Zinc biosorption was performed at pH 4, room temperature and stirring 800 rpm. Variation of contact time used was 30, 60 and 120 min; and the amount of biomass used was 0.01 g, 0.02 g, 0.03 g, 0.04 g and 0.05 g. The highest zinc biosorption capacity was obtained 25.43% at the time of 120 minutes and the amount of biomass used 0.01 g. The optimum condition for biomass biosorption and removal capacity based on the correlation between experimental data and mathematical models was obtained with the addition of 0.04 g of biomass with correlation coefficient (R 1 and 0,965 respectively.ABSTRAK Salah satu logam berat yang berbahaya dari hasil kegiatan industri adalah logam Zn (seng. Biosorpsi logam Zn pada limbah sintetik dilakukan dengan menggunakan biomassa campuran Pseudomonas aeruginosa dan Pseudomonas sp. Penelitian ini bertujuan untuk mengetahui kapasitas biomassa dalam mengadsorpsi logam Zn pada limbah sintetik. Biosorpsi logam Zn dilakukan pada kondisi pH 4, temperatur ruang dan pengadukan 800 rpm. Variasi waktu kontak dilakukan pada 30, 60 dan 120 menit  dan menggunakan jumlah biomassa 0,01 g, 0,02 g, 0,03 g, 0,04 g  dan 0,05 g. Kapasitas biosorpsi logam Zn tertinggi diperoleh sebesar 25,43% pada waktu 120 menit dengan jumlah biomassa 0,01 g. Kondisi optimum biosorpsi logam Zn berdasarkan korelasi antara data eksperimen dan model matematika diperoleh pada penambahan jumlah biomassa sebesar 0,04 g baik untuk kapasitas biosorpsi logam Zn maupun efisiensi removal logam Zn dengan nilai koefisien korelasi (R2 masing-masing adalah 1 dan 0,965.

  18. Pseudomonas aeruginosa Alginate Overproduction Promotes Coexistence with Staphylococcus aureus in a Model of Cystic Fibrosis Respiratory Infection.

    Science.gov (United States)

    Limoli, Dominique H; Whitfield, Gregory B; Kitao, Tomoe; Ivey, Melissa L; Davis, Michael R; Grahl, Nora; Hogan, Deborah A; Rahme, Laurence G; Howell, P Lynne; O'Toole, George A; Goldberg, Joanna B

    2017-03-21

    While complex intra- and interspecies microbial community dynamics are apparent during chronic infections and likely alter patient health outcomes, our understanding of these interactions is currently limited. For example, Pseudomonas aeruginosa and Staphylococcus aureus are often found to coinfect the lungs of patients with cystic fibrosis (CF), yet these organisms compete under laboratory conditions. Recent observations that coinfection correlates with decreased health outcomes necessitate we develop a greater understanding of these interbacterial interactions. In this study, we tested the hypothesis that P. aeruginosa and/or S. aureus adopts phenotypes that allow coexistence during infection. We compared competitive interactions of P. aeruginosa and S. aureus isolates from mono- or coinfected CF patients employing in vitro coculture models. P. aeruginosa isolates from monoinfected patients were more competitive toward S. aureus than P. aeruginosa isolates from coinfected patients. We also observed that the least competitive P. aeruginosa isolates possessed a mucoid phenotype. Mucoidy occurs upon constitutive activation of the sigma factor AlgT/U, which regulates synthesis of the polysaccharide alginate and dozens of other secreted factors, including some previously described to kill S. aureus Here, we show that production of alginate in mucoid strains is sufficient to inhibit anti-S. aureus activity independent of activation of the AlgT regulon. Alginate reduces production of siderophores, 2-heptyl-4-hydroxyquinolone-N-oxide (HQNO), and rhamnolipids-each required for efficient killing of S. aureus These studies demonstrate alginate overproduction may be an important factor driving P. aeruginosa coinfection with S. aureusIMPORTANCE Numerous deep-sequencing studies have revealed the microbial communities present during respiratory infections in cystic fibrosis (CF) patients are diverse, complex, and dynamic. We now face the challenge of determining

  19. Pseudomonas aeruginosa forms Biofilms in Acute InfectionIndependent of Cell-to-Cell Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Schaber, J. Andy; Triffo, W.J.; Suh, Sang J.; Oliver, Jeffrey W.; Hastert, Mary C.; Griswold, John A.; Auer, Manfred; Hamood, Abdul N.; Rumbaugh, Kendra P.

    2006-09-20

    Biofilms are bacterial communities residing within a polysaccharide matrix that are associated with persistence and antibiotic resistance in chronic infections. We show that the opportunistic pathogen Pseudomonas aeruginosa forms biofilms within 8 hours of infection in thermally-injured mice, demonstrating that biofilms contribute to bacterial colonization in acute infections. P. aeruginosa biofilms were visualized within burned tissue surrounding blood vessels and adipose cells. Although quorum sensing (QS), a bacterial signaling mechanism, coordinates differentiation of biofilms in vitro, wild type and QS-deficient P. aeruginosa formed similar biofilms in vivo. Our findings demonstrate that P. aeruginosa forms biofilms on specific host tissues independent of QS.

  20. Quorum-sensing-regulated virulence factors in Pseudomonas aeruginosa are toxic to Lucilia sericata maggots

    DEFF Research Database (Denmark)

    Andersen, A S; Jørgensen, Bo; Bjarnsholt, T

    2010-01-01

    Maggot debridement therapy (MDT) is widely used for debridement of chronic infected wounds; however, for wounds harbouring specific bacteria limited effect or failure of the treatment has been described. Here we studied the survival of Lucilia sericata maggots encountering Pseudomonas aeruginosa...... for the presence of QS inhibitors; only high doses of ES showed inhibition of QS in P. aeruginosa. Thus P. aeruginosa was shown to be toxic to L. sericata maggots. This, coupled to the preferential feeding by the maggots and reduced ingestion of P. aeruginosa, could explain MDT failure in wounds colonized by P...

  1. Blow fly Lucilia sericata nuclease digests DNA associated with wound slough/eschar and with Pseudomonas aeruginosa biofilm.

    Science.gov (United States)

    Brown, A; Horobin, A; Blount, D G; Hill, P J; English, J; Rich, A; Williams, P M; Pritchard, D I

    2012-12-01

    In chronic wounds, it may be clinically important to remove extracellular bacterial and patient DNA as its presence may impede wound healing and promote bacterial survival in biofilm, in which extracellular DNA forms part of the biofilm architecture. As medicinal maggots, larvae of Lucilia sericata Meigen (Diptera: Calliphoridae) have been shown to efficiently debride wounds it became of interest to investigate their excretions/secretions (ES) for the presence of a deoxyribonuclease (DNAse) activity. Excretions/secretions products were shown to contain a DNAse, with magnesium, sodium and calcium metal ion dependency, and a native molecular mass following affinity purification of approximately 45 kDa. The affinity purified DNAse degraded genomic bacterial DNA per se, DNA from the slough/eschar of a venous leg ulcer, and extracellular bacterial DNA in biofilms pre-formed from a clinical isolate of Pseudomonas aeruginosa. The latter finding highlights an important attribute of the DNAse, given the frequency of P. aeruginosa infection in non-healing wounds and the fact that P. aeruginosa virulence factors can be toxic to maggots. Maggot DNAse is thus a competent enzyme derived from a rational source, with the potential to assist in clinical wound debridement by removing extracellular DNA from tissue and biofilm, and promoting tissue viability, while liberating proteinaceous slough/eschar for debridement by the suite of proteinases secreted by L. sericata. © 2012 The Authors. Medical and Veterinary Entomology © 2012 The Royal Entomological Society.

  2. Pseudomonas aeruginosa in Dairy Goats: Genotypic and Phenotypic Comparison of Intramammary and Environmental Isolates

    Science.gov (United States)

    Scaccabarozzi, Licia; Leoni, Livia; Ballarini, Annalisa; Barberio, Antonio; Locatelli, Clara; Casula, Antonio; Bronzo, Valerio; Pisoni, Giuliano; Jousson, Olivier; Morandi, Stefano; Rapetti, Luca; García-Fernández, Aurora; Moroni, Paolo

    2015-01-01

    Following the identification of a case of severe clinical mastitis in a Saanen dairy goat (goat A), an average of 26 lactating goats in the herd was monitored over a period of 11 months. Milk microbiological analysis revealed the presence of Pseudomonas aeruginosa in 7 of the goats. Among these 7 does, only goat A showed clinical signs of mastitis. The 7 P. aeruginosa isolates from the goat milk and 26 P. aeruginosa isolates from environmental samples were clustered by RAPD-PCR and PFGE analyses in 3 genotypes (G1, G2, G3) and 4 clusters (A, B, C, D), respectively. PFGE clusters A and B correlated with the G1 genotype and included the 7 milk isolates. Although it was not possible to identify the infection source, these results strongly suggest a spreading of the infection from goat A. Clusters C and D overlapped with genotypes G2 and G3, respectively, and included only environmental isolates. The outcome of the antimicrobial susceptibility test performed on the isolates revealed 2 main patterns of multiple resistance to beta-lactam antibiotics and macrolides. Virulence related phenotypes were analyzed, such as swarming and swimming motility, production of biofilm and production of secreted virulence factors. The isolates had distinct phenotypic profiles, corresponding to genotypes G1, G2 and G3. Overall, correlation analysis showed a strong correlation between sampling source, RAPD genotype, PFGE clusters, and phenotypic clusters. The comparison of the levels of virulence related phenotypes did not indicate a higher pathogenic potential in the milk isolates as compared to the environmental isolates. PMID:26606430

  3. The single-nucleotide resolution transcriptome of Pseudomonas aeruginosa grown in body temperature.

    Directory of Open Access Journals (Sweden)

    Omri Wurtzel

    2012-09-01

    Full Text Available One of the hallmarks of opportunistic pathogens is their ability to adjust and respond to a wide range of environmental and host-associated conditions. The human pathogen Pseudomonas aeruginosa has an ability to thrive in a variety of hosts and cause a range of acute and chronic infections in individuals with impaired host defenses or cystic fibrosis. Here we report an in-depth transcriptional profiling of this organism when grown at host-related temperatures. Using RNA-seq of samples from P. aeruginosa grown at 28°C and 37°C we detected genes preferentially expressed at the body temperature of mammalian hosts, suggesting that they play a role during infection. These temperature-induced genes included the type III secretion system (T3SS genes and effectors, as well as the genes responsible for phenazines biosynthesis. Using genome-wide transcription start site (TSS mapping by RNA-seq we were able to accurately define the promoters and cis-acting RNA elements of many genes, and uncovered new genes and previously unrecognized non-coding RNAs directly controlled by the LasR quorum sensing regulator. Overall we identified 165 small RNAs and over 380 cis-antisense RNAs, some of which predicted to perform regulatory functions, and found that non-coding RNAs are preferentially localized in pathogenicity islands and horizontally transferred regions. Our work identifies regulatory features of P. aeruginosa genes whose products play a role in environmental adaption during infection and provides a reference transcriptional landscape for this pathogen.

  4. Pseudomonas aeruginosa in Dairy Goats: Genotypic and Phenotypic Comparison of Intramammary and Environmental Isolates.

    Science.gov (United States)

    Scaccabarozzi, Licia; Leoni, Livia; Ballarini, Annalisa; Barberio, Antonio; Locatelli, Clara; Casula, Antonio; Bronzo, Valerio; Pisoni, Giuliano; Jousson, Olivier; Morandi, Stefano; Rapetti, Luca; García-Fernández, Aurora; Moroni, Paolo

    2015-01-01

    Following the identification of a case of severe clinical mastitis in a Saanen dairy goat (goat A), an average of 26 lactating goats in the herd was monitored over a period of 11 months. Milk microbiological analysis revealed the presence of Pseudomonas aeruginosa in 7 of the goats. Among these 7 does, only goat A showed clinical signs of mastitis. The 7 P. aeruginosa isolates from the goat milk and 26 P. aeruginosa isolates from environmental samples were clustered by RAPD-PCR and PFGE analyses in 3 genotypes (G1, G2, G3) and 4 clusters (A, B, C, D), respectively. PFGE clusters A and B correlated with the G1 genotype and included the 7 milk isolates. Although it was not possible to identify the infection source, these results strongly suggest a spreading of the infection from goat A. Clusters C and D overlapped with genotypes G2 and G3, respectively, and included only environmental isolates. The outcome of the antimicrobial susceptibility test performed on the isolates revealed 2 main patterns of multiple resistance to beta-lactam antibiotics and macrolides. Virulence related phenotypes were analyzed, such as swarming and swimming motility, production of biofilm and production of secreted virulence factors. The isolates had distinct phenotypic profiles, corresponding to genotypes G1, G2 and G3. Overall, correlation analysis showed a strong correlation between sampling source, RAPD genotype, PFGE clusters, and phenotypic clusters. The comparison of the levels of virulence related phenotypes did not indicate a higher pathogenic potential in the milk isolates as compared to the environmental isolates.

  5. Pseudomonas aeruginosa in Dairy Goats: Genotypic and Phenotypic Comparison of Intramammary and Environmental Isolates.

    Directory of Open Access Journals (Sweden)

    Licia Scaccabarozzi

    Full Text Available Following the identification of a case of severe clinical mastitis in a Saanen dairy goat (goat A, an average of 26 lactating goats in the herd was monitored over a period of 11 months. Milk microbiological analysis revealed the presence of Pseudomonas aeruginosa in 7 of the goats. Among these 7 does, only goat A showed clinical signs of mastitis. The 7 P. aeruginosa isolates from the goat milk and 26 P. aeruginosa isolates from environmental samples were clustered by RAPD-PCR and PFGE analyses in 3 genotypes (G1, G2, G3 and 4 clusters (A, B, C, D, respectively. PFGE clusters A and B correlated with the G1 genotype and included the 7 milk isolates. Although it was not possible to identify the infection source, these results strongly suggest a spreading of the infection from goat A. Clusters C and D overlapped with genotypes G2 and G3, respectively, and included only environmental isolates. The outcome of the antimicrobial susceptibility test performed on the isolates revealed 2 main patterns of multiple resistance to beta-lactam antibiotics and macrolides. Virulence related phenotypes were analyzed, such as swarming and swimming motility, production of biofilm and production of secreted virulence factors. The isolates had distinct phenotypic profiles, corresponding to genotypes G1, G2 and G3. Overall, correlation analysis showed a strong correlation between sampling source, RAPD genotype, PFGE clusters, and phenotypic clusters. The comparison of the levels of virulence related phenotypes did not indicate a higher pathogenic potential in the milk isolates as compared to the environmental isolates.

  6. Intensive care unit-acquired pneumonia due to Pseudomonas aeruginosa with and without multidrug resistance.

    Science.gov (United States)

    Fernández-Barat, Laia; Ferrer, Miquel; De Rosa, Francesca; Gabarrús, Albert; Esperatti, Mariano; Terraneo, Silvia; Rinaudo, Mariano; Li Bassi, Gianluigi; Torres, Antoni

    2017-02-01

    Pseudomonas aeruginosa often presents multi-drug resistance (MDR) in intensive care unit (ICU)-acquired pneumonia (ICUAP), possibly resulting in inappropriate empiric treatment and worse outcomes. We aimed to identify patients with ICUAP at risk for these pathogens in order to improve treatment selection and outcomes. We prospectively assessed 222 consecutive immunocompetent ICUAP patients confirmed microbiologically. We determined the characteristics, risk factors, systemic inflammatory response and outcomes of P. aeruginosa pneumonia (Pa-ICUAP), compared to other aetiologies. We also compared patients with MDR vs. non-MDR Pa-ICUAP. Pseudomonas aeruginosa was the most frequent aetiology (64, 29%); 22 (34%) cases had MDR. Independent predictors for Pa-ICUAP were prior airway colonization by P. aeruginosa, previous antibiotic treatment, solid cancer and shock; alcohol abuse and pleural effusion were independently associated to lower risk for Pa-ICUAP. Chronic liver disease independently predicted MDR among Pa-ICUAP. The inflammatory biomarkers were similar between all groups. Patients with Pa-ICUAP had lower unadjusted 90-day survival (p = 0.049). However, the 90-day survival adjusted for confounding factors using a propensity score did not differ between all groups. Pseudomonas aeruginosa remains the most frequent aetiology of ICUAP, with high prevalence of MDR. These risk factors should be taken into account to avoid inappropriate empiric antibiotics for Pa-ICUAP. Pseudomonas aeruginosa, regardless multidrug resistance, was not associated with different propensity-adjusted survival. Copyright © 2016 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  7. Pseudomonas aeruginosa promotes Escherichia coli biofilm formation in nutrient-limited medium.

    Directory of Open Access Journals (Sweden)

    Alessandro Culotti

    Full Text Available Biofilms have been implicated as an important reservoir for pathogens and commensal enteric bacteria such as Escherichia coli in natural and engineered water systems. However, the processes that regulate the survival of E. coli in aquatic biofilms have not been thoroughly studied. We examined the effects of hydrodynamic shear and nutrient concentrations on E. coli colonization of pre-established Pseudomonas aeruginosa biofilms, co-inoculation of E. coli and P. aeruginosa biofilms, and P. aeruginosa colonization of pre-established E. coli biofilms. In nutritionally-limited R2A medium, E. coli dominated biofilms when co-inoculated with P. aeruginosa, and successfully colonized and overgrew pre-established P. aeruginosa biofilms. In more enriched media, P. aeruginosa formed larger clusters, but E. coli still extensively overgrew and colonized the interior of P. aeruginosa clusters. In mono-culture, E. coli formed sparse and discontinuous biofilms. After P. aeruginosa was introduced to these biofilms, E. coli growth increased substantially, resulting in patterns of biofilm colonization similar to those observed under other sequences of organism introduction, i.e., E. coli overgrew P. aeruginosa and colonized the interior of P. aeruginosa clusters. These results demonstrate that E. coli not only persists in aquatic biofilms under depleted nutritional conditions, but interactions with P. aeruginosa can greatly increase E. coli growth in biofilms under these experimental conditions.

  8. Pseudomonas aeruginosa Alginate Overproduction Promotes Coexistence with Staphylococcus aureus in a Model of Cystic Fibrosis Respiratory Infection

    Directory of Open Access Journals (Sweden)

    Dominique H. Limoli

    2017-03-01

    Full Text Available While complex intra- and interspecies microbial community dynamics are apparent during chronic infections and likely alter patient health outcomes, our understanding of these interactions is currently limited. For example, Pseudomonas aeruginosa and Staphylococcus aureus are often found to coinfect the lungs of patients with cystic fibrosis (CF, yet these organisms compete under laboratory conditions. Recent observations that coinfection correlates with decreased health outcomes necessitate we develop a greater understanding of these interbacterial interactions. In this study, we tested the hypothesis that P. aeruginosa and/or S. aureus adopts phenotypes that allow coexistence during infection. We compared competitive interactions of P. aeruginosa and S. aureus isolates from mono- or coinfected CF patients employing in vitro coculture models. P. aeruginosa isolates from monoinfected patients were more competitive toward S. aureus than P. aeruginosa isolates from coinfected patients. We also observed that the least competitive P. aeruginosa isolates possessed a mucoid phenotype. Mucoidy occurs upon constitutive activation of the sigma factor AlgT/U, which regulates synthesis of the polysaccharide alginate and dozens of other secreted factors, including some previously described to kill S. aureus. Here, we show that production of alginate in mucoid strains is sufficient to inhibit anti-S. aureus activity independent of activation of the AlgT regulon. Alginate reduces production of siderophores, 2-heptyl-4-hydroxyquinolone-N-oxide (HQNO, and rhamnolipids—each required for efficient killing of S. aureus. These studies demonstrate alginate overproduction may be an important factor driving P. aeruginosa coinfection with S. aureus.

  9. FimL regulates cAMP synthesis in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Yuki F Inclan

    2011-01-01

    Full Text Available Pseudomonas aeruginosa, a ubiquitous bacteria found in diverse ecological niches, is an important cause of acute infections in immunocompromised individuals and chronic infections in patients with Cystic Fibrosis. One signaling molecule required for the coordinate regulation of virulence factors associated with acute infections is 3', 5'-cyclic adenosine monophosphate, (cAMP, which binds to and activates a catabolite repressor homolog, Vfr. Vfr controls the transcription of many virulence factors, including those associated with Type IV pili (TFP, the Type III secretion system (T3SS, the Type II secretion system, flagellar-mediated motility, and quorum sensing systems. We previously identified FimL, a protein with histidine phosphotransfer-like domains, as a regulator of Vfr-dependent processes, including TFP-dependent motility and T3SS function. In this study, we carried out genetic and physiologic studies to further define the mechanism of action of FimL. Through a genetic screen designed to identify suppressors of FimL, we found a putative cAMP-specific phosphodiesterase (CpdA, suggesting that FimL regulates cAMP levels. Inactivation of CpdA increases cAMP levels and restores TFP-dependent motility and T3SS function to fimL mutants, consistent with in vivo phosphodiesterase activity. By constructing combinations of double and triple mutants in the two adenylate cyclase genes (cyaA and cyaB, fimL, and cpdA, we show that ΔfimL mutants resemble ΔcyaB mutants in TM defects, decreased T3SS transcription, and decreased cAMP levels. Similar to some of the virulence factors that they regulate, we demonstrate that CyaB and FimL are polarly localized. These results reveal new complexities in the regulation of diverse virulence pathways associated with acute P. aeruginosa infections.

  10. The Multiple Signaling Systems Regulating Virulence in Pseudomonas aeruginosa

    Science.gov (United States)

    Nadal Jimenez, Pol; Koch, Gudrun; Thompson, Jessica A.; Xavier, Karina B.; Cool, Robbert H.

    2012-01-01

    Summary: Cell-to-cell communication is a major process that allows bacteria to sense and coordinately react to the fluctuating conditions of the surrounding environment. In several pathogens, this process triggers the production of virulence factors and/or a switch in bacterial lifestyle that is a major determining factor in the outcome and severity of the infection. Understanding how bacteria control these signaling systems is crucial to the development of novel antimicrobial agents capable of reducing virulence while allowing the immune system of the host to clear bacterial infection, an approach likely to reduce the selective pressures for development of resistance. We provide here an up-to-date overview of the molecular basis and physiological implications of cell-to-cell signaling systems in Gram-negative bacteria, focusing on the well-studied bacterium Pseudomonas aeruginosa. All of the known cell-to-cell signaling systems in this bacterium are described, from the most-studied systems, i.e., N-acyl homoserine lactones (AHLs), the 4-quinolones, the global activator of antibiotic and cyanide synthesis (GAC), the cyclic di-GMP (c-di-GMP) and cyclic AMP (cAMP) systems, and the alarmones guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp), to less-well-studied signaling molecules, including diketopiperazines, fatty acids (diffusible signal factor [DSF]-like factors), pyoverdine, and pyocyanin. This overview clearly illustrates that bacterial communication is far more complex than initially thought and delivers a clear distinction between signals that are quorum sensing dependent and those relying on alternative factors for their production. PMID:22390972

  11. Endoftalmitis posvitrectomía por Pseudomona aeruginosa

    Directory of Open Access Journals (Sweden)

    Violeta Rodríguez Rodríguez

    Full Text Available Se describe el caso de un paciente varón de 22 años, miope, sometido a vitrectomía pars plana 23 G en ojo único (valioso, por desprendimiento de retina regmatógeno. A las 24 horas presentó pérdida de visión, dolor, signos inflamatorios en globo y anejos oculares. Acudió al Servicio de Emergencias, donde se decidió su ingreso hospitalario para la toma de muestra y la aplicación de inyección intravítrea de vancomicina (1 mg/0,1 mL y ceftazidima (2 mg/0,1 mL, con lo que mostró mejoría clínica. El estudio microbiológico reportó Pseudomona aeruginosa sensible a la ceftazidima y a la ciprofloxacina. La mejor visualización fundoscópica al quinto día posintravítrea permitió observar depósitos blanquecinos en la interfaz aceite de silicona-retina, y se decidió la extracción de aceite por incisiones mixtas 23 g y 20 g (infusión, endoiluminación y extracción respectivamente, lavado de cámara anterior, cámara vítrea, reposición de aceite de silicón y segunda dosis de ceftazidima, con evolución posoperatoria favorable. Se dio el alta una semana después, con la retina aplicada y una mejor visión corregida de 0,1.

  12. Reexamining intra and extracellular metabolites produced by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Maria Shuja

    2016-02-01

    Full Text Available Objective: To isolate, screen and analyze bacteria from different areas of Pakistan for the production of antimicrobial compounds, zinc solubilization and bioplastic production. Methods: Isolation and purification was proceeding with streak plate method. Antagonistic assay was completed with well diffusion and thin-layer chromatography. In vivo analysis of bioplastic was analyzed with Nile blue fluorescence under UV and Sudan staining. Results: A total of 18 bacterial strains purified from soil samples while 148 strains form stock cultures were used. Out of 166 only 94 showed antimicrobial activity against each of Grampositive and Gram-negative; cocci and rods. In case of heavy metal (ZnO and Zn3(PO42.4H2O solubilization, 54 strains solubilized ZnO and 23 strains solubilized Zn3(PO42.4H2O, while 127 strains grown on polyhydroxyalkanoate detection meedia supplemented with Nile blue medium showed bioplastic production by producing fluorescence under UV light. Four bacterial strains (coded as 100, 101, 104 and 111 were selected for further characterization. Induction time assay showed that strains 101, 104, and 111 showed inhibitory activity after 4 h of incubation while strain 100 showed after 8 h. All four strains were tolerable to the maximum concentration of ZnO. Amplified products of both 16S rRNA and PhaC gene fragments of strain 111 were sequenced and submitted to GenBank as accession numbers EU781525 and EU781526. Conclusions: Bacterial strain Pseudomonas aeruginosa-111 has potential to utilize as biofertilize and bioplastic producer.

  13. Isolation and characterization of gallium resistant Pseudomonas aeruginosa mutants.

    Science.gov (United States)

    García-Contreras, Rodolfo; Lira-Silva, Elizabeth; Jasso-Chávez, Ricardo; Hernández-González, Ismael L; Maeda, Toshinari; Hashimoto, Takahiro; Boogerd, Fred C; Sheng, Lili; Wood, Thomas K; Moreno-Sánchez, Rafael

    2013-12-01

    Pseudomonas aeruginosa PA14 cells resistant to the novel antimicrobial gallium nitrate (Ga) were developed using transposon mutagenesis and by selecting spontaneous mutants. The mutants showing the highest growth in the presence of Ga were selected for further characterization. These mutants showed 4- to 12-fold higher Ga minimal inhibitory growth concentrations and a greater than 8-fold increase in the minimum biofilm eliminating Ga concentration. Both types of mutants produced Ga resistant biofilms whereas the formation of wild-type biofilms was strongly inhibited by Ga. The gene interrupted in the transposon mutant was hitA, which encodes a periplasmic iron binding protein that delivers Fe³⁺ to the HitB iron permease; complementation of the mutant with the hitA gene restored the Ga sensitivity. This hitA mutant showed a 14-fold decrease in Ga internalization versus the wild-type strain, indicating that the HitAB system is also involved in the Ga uptake. Ga uptake in the spontaneous mutant was also lower, although no mutations were found in the hitAB genes. Instead, this mutant harbored 64 non-silent mutations in several genes including those of the phenazine pyocyanin biosynthesis. The spontaneous mutant produced 2-fold higher pyocyanin basal levels than the wild-type; the addition of this phenazine to wild-type cultures protected them from the Ga bacteriostatic effect. The present data indicate that mutations affecting Ga transport and probably pyocyanin biosynthesis enable cells to develop resistance to Ga. Copyright © 2013 Elsevier GmbH. All rights reserved.

  14. A gacS deletion in Pseudomonas aeruginosa cystic fibrosis isolate CHA shapes its virulence.

    Directory of Open Access Journals (Sweden)

    Khady Mayebine Sall

    Full Text Available Pseudomonas aeruginosa, a human opportunistic pathogen, is capable of provoking acute and chronic infections that are associated with defined sets of virulence factors. During chronic infections, the bacterium accumulates mutations that silence some and activate other genes. Here we show that the cystic fibrosis isolate CHA exhibits a unique virulence phenotype featuring a mucoid morphology, an active Type III Secretion System (T3SS, hallmark of acute infections, and no Type VI Secretion System (H1-T6SS. This virulence profile is due to a 426 bp deletion in the 3' end of the gacS gene encoding an essential regulatory protein. The absence of GacS disturbs the Gac/Rsm pathway leading to depletion of the small regulatory RNAs RsmY/RsmZ and, in consequence, to expression of T3SS, while switching off the expression of H1-T6SS and Pel polysaccharides. The CHA isolate also exhibits full ability to swim and twitch, due to active flagellum and Type IVa pili. Thus, unlike the classical scheme of balance between virulence factors, clinical strains may adapt to a local niche by expressing both alginate exopolysaccharide, a hallmark of membrane stress that protects from antibiotic action, host defences and phagocytosis, and efficient T3S machinery that is considered as an aggressive virulence factor.

  15. One-step purification and characterization of alginate lyase from a clinical Pseudomonas aeruginosa with destructive activity on bacterial biofilm

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    Parinaz Ghadam

    2017-05-01

    Full Text Available Objective(s: Pseudomonas aeruginosais a Gram-negative and aerobic rod bacterium that displays mucoid and non-mucoid phenotype. Mucoid strains secrete alginate, which is the main agent of biofilms in chronic P. aeruginosa infections, show high resistance to antibiotics; consequently, the biological disruption of mucoid P. aeruginosa biofilms is an attractive area of study for researchers. Alginate lyase gene (algl is a member of alginate producing operon which by glycosidase activity produces primer for other enzymes in this cluster. Also this activity can destroy the extracellular alginate; therefore this enzyme participates in alginate production and destruction pathway. Alginate lyase causes detachment of a biofilm by reducing its adhesion to the surfaces, and increases phagocytosis and antibiotic susceptibility. In this study, alginate lyase was purified in just one step and its properties were investigated. Materials and Methods: The purification was done by affinity chromatography, analysed by SDS-PAGE, and its effect on P. aeruginosa biofilms was surveyed by micro titer plate assay and SEM. The substrate specificity of the enzyme was determined by PCR. Results: Alginate lyase from isolate 48 was purified in one step. It is more thermally resistant than alginate lyase from Pseudomonas aeruginosa PAO1 and poly M, poly G and poly MG alginate were the substrate of this enzyme. Moreover, it has an eradication effect on biofilms from P. aeruginosa 48 and PAO1. Conclusion: In this study an alginate lyase with many characteristics suitable in medicine such as thermal stability, effective on poly M alginate, and bacterial biofilm destructive was introduced and purified.

  16. Comparison of Neutrophil Apoptosis by the Pseudomonas Aeruginosa Exotoxins between Healthy Individuals and Term Infants

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    Soheila Khazaei

    2013-04-01

    Full Text Available Background: Pseudomonas aeruginosa may be colonized in different human tissues and result in some infections potentially. Thus, considering that these bacteria are resistance to most of the current antibiotics, an examination on pathogenesis mechanisms of such bacteria can be effective in controlling the infections developed by it.Materials and Methods: In this project, among 40 blood samples (20 healthy persons, 20 infants, an amount of 5 ml (2 ml in the infants heparinized blood was collected form each and then neutrophils were isolated by a standard method and were counted by neubauer lam. After culturing Pseudomonas bacteria in broth medium, some tubes with densities of 1, 2, 3 and 4 McFarland were prepared and the bacteria were isolated by centrifuge method with 3000rpm for 10 minutes and then its exotoxin were exposed to neutrophils of the groups under study. The effect of time and the bacteria count on the amount of the secreted toxin and in adjacency to neutrophils was measured.Results: There were 11 men and 9 women in the health group and the infants group consisted of 12 boys and 8 girls. Death cell percentage of neutrophils was 100% in the health group and 8.90% in the infants group. Percentage of bacterial growth in the medium 1 and 2 McFarland was zero; in the medium 3 McFarland, it was 12.5% in the healthy group and 1% in the infants group (p<0.10. The average rate of cell death in the minute 15th was different in two groups (68.5% in health group vs. 92.5% in the infants (p<0.0005. Conclusion: This study showed the effect of Pseudomonas bacteria on the development of early cell death in the infants very well. As it was shown, this effect is time-dependent and this cell death (apoptosis is occurred in the infants earlier than health people.

  17. Baicalein attenuates the quorum sensing-controlled virulence factors of Pseudomonas aeruginosa and relieves the inflammatory response in P. aeruginosa-infected macrophages by downregulating the MAPK and NFκB signal-transduction pathways

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    Luo J

    2016-01-01

    Full Text Available Jing Luo,* Jin-liang Kong,* Bi-ying Dong, Hong Huang, Ke Wang, Li-hong Wu, Chang-chun Hou, Yue Liang, Bing Li, Yi-qiang Chen Department of Respiratory Disease, First Affiliated Hospital of Guangxi Medical University, Nanning, People’s Republic of China *These authors contributed equally to this work Abstract: Burgeoning antibiotic resistance and unfavorable outcomes of inflammatory injury after Pseudomonas aeruginosa infection have necessitated the development of novel agents that not only target quorum sensing (QS but also combat inflammatory injury with the least risk of resistance. This study aimed to assess the anti-QS and anti-inflammatory activities of baicalein, a traditional herbal medicine that is widely used in the People’s Republic of China, against P. aeruginosa infection. We found that subminimum inhibitory concentrations of baicalein efficiently interfered with the QS-signaling pathway of P. aeruginosa via downregulation of the transcription of QS-regulated genes and the translation of QS-signaling molecules. This interference resulted in the global attenuation of QS-controlled virulence factors, such as motility and biofilm formation, and the secretion into the culture supernatant of extracellular virulence factors, including pyocyanin, LasA protease, LasB elastase, and rhamnolipids. Moreover, we examined the anti-inflammatory activity of baicalein and its mode of action via a P. aeruginosa-infected macrophage model to address its therapeutic effect. Baicalein reduced the P. aeruginosa-induced secretion of the inflammatory cytokines IL-1β, IL-6, IL-8, and TNFα. In addition, baicalein suppressed P. aeruginosa-induced activation of the MAPK and NFκB signal-transduction pathways in cocultured macrophages; this may be the mechanism by which baicalein inhibits the production of proinflammatory cytokines. Therefore, our study demonstrates that baicalein represents a potential treatment for P. aeruginosa infection because it

  18. A case of orbital apex syndrome due to Pseudomonas aeruginosa infection

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    Takeshi Kusunoki

    2011-11-01

    Full Text Available Orbital apex syndrome is commonly been thought to have a poor prognosis. Many cases of this syndrome have been reported to be caused by paranasal sinus mycosis. We encountered a very rare case (60-year-old woman of sinusitis with orbital apex syndrome due to Pseudomonas aeruginosa infection. She had received insulin and dialysis for diabtes and diabetic nephropathy, moreover anticoagulants after heart by-pass surgery. She underwent endoscopic sinus operation and was treated with antibiotics, but her loss of left vision did not improve. Recently, sinusitis cases due to Pseudomonas aeruginosa were reported to be a increasing. Therefore, we should consider the possibility of Pseudomonas aeruginosa as well as mycosis as infections of the sinus, especially inpatients who are immunocompromised body.

  19. A case of orbital apex syndrome due to Pseudomonas aeruginosa infection.

    Science.gov (United States)

    Kusunoki, Takeshi; Kase, Kaori; Ikeda, Katsuhisa

    2011-09-28

    Orbital apex syndrome is commonly been thought to have a poor prognosis. Many cases of this syndrome have been reported to be caused by paranasal sinus mycosis. We encountered a very rare case (60-year-old woman) of sinusitis with orbital apex syndrome due to Pseudomonas aeruginosa infection. She had received insulin and dialysis for diabtes and diabetic nephropathy, moreover anticoagulants after heart by-pass surgery. She underwent endoscopic sinus operation and was treated with antibiotics, but her loss of left vision did not improve. Recently, sinusitis cases due to Pseudomonas aeruginosa were reported to be a increasing. Therefore, we should consider the possibility of Pseudomonas aeruginosa as well as mycosis as infections of the sinus, especially inpatients who are immunocompromised body.

  20. Structural Insights on the Bacteriolytic and Self-protection Mechanism of Muramidase Effector Tse3 in Pseudomonas aeruginosa*

    Science.gov (United States)

    Li, Lianbo; Zhang, Weili; Liu, Qisong; Gao, Yu; Gao, Ying; Wang, Yun; Wang, David Zhigang; Li, Zigang; Wang, Tao

    2013-01-01

    The warfare among microbial species as well as between pathogens and hosts is fierce, complicated, and continuous. In Pseudomonas aeruginosa, the muramidase effector Tse3 (Type VI secretion exported 3) can be injected into the periplasm of neighboring bacterial competitors by a Type VI secretion apparatus, eventually leading to cell lysis and death. However, P. aeruginosa protects itself from lysis by expressing immune protein Tsi3 (Type six secretion immunity 3). Here, we report the crystal structure of the Tse3-Tsi3 complex at 1.8 Å resolution, revealing that Tse3 possesses one open accessible, goose-type lysozyme-like domain with peptidoglycan hydrolysis activity. Calcium ions bind specifically in the Tse3 active site and are identified to be crucial for its bacteriolytic activity. In combination with biochemical studies, the structural basis of self-protection mechanism of Tsi3 is also elucidated, thus providing an understanding and new insights into the effectors of Type VI secretion system. PMID:24025333

  1. Distinct roles of extracellular polymeric substances in Pseudomonas aeruginosa biofilm development

    DEFF Research Database (Denmark)

    Yang, Liang; Hu, Yifan; Liu, Yang

    2011-01-01

    differentiation remain largely unknown. The distinct roles of different EPS have been addressed in the present report. Both Pel and Psl polysaccharides are required for type IV pilus‐independent microcolony formation in the initial stages of biofilm formation by Pseudomonas aeruginosa PAO1. Both Pel and Psl...... polysaccharides are also essential for subpopulation interactions and macrocolony formation in the later stages of P. aeruginosa PAO1 biofilm formation. Pel and Psl polysaccharides have different impacts on Pseudomonas quinolone signal‐mediated extracellular DNA release in P. aeruginosa PAO1 biofilms. Psl...... polysaccharide is more important than Pel polysaccharide in P. aeruginosa PAO1 biofilm formation and antibiotic resistance. Our study thus suggests that different EPS materials play distinct roles during bacterial biofilm formation....

  2. Strong incidence of Pseudomonas aeruginosa on bacterial rrs and ITS genetic structures of cystic fibrosis sputa.

    Science.gov (United States)

    Pages-Monteiro, Laurence; Marti, Romain; Commun, Carine; Alliot, Nolwenn; Bardel, Claire; Meugnier, Helene; Perouse-de-Montclos, Michele; Reix, Philippe; Durieu, Isabelle; Durupt, Stephane; Vandenesch, Francois; Freney, Jean; Cournoyer, Benoit; Doleans-Jordheim, Anne

    2017-01-01

    Cystic fibrosis (CF) lungs harbor a complex community of interacting microbes, including pathogens like Pseudomonas aeruginosa. Meta-taxogenomic analysis based on V5-V6 rrs PCR products of 52 P. aeruginosa-positive (Pp) and 52 P. aeruginosa-negative (Pn) pooled DNA extracts from CF sputa suggested positive associations between P. aeruginosa and Stenotrophomonas and Prevotella, but negative ones with Haemophilus, Neisseria and Burkholderia. Internal Transcribed Spacer analyses (RISA) from individual DNA extracts identified three significant genetic structures within the CF cohorts, and indicated an impact of P. aeruginosa. RISA clusters Ip and IIIp contained CF sputa with a P. aeruginosa prevalence above 93%, and of 24.2% in cluster IIp. Clusters Ip and IIIp showed lower RISA genetic diversity and richness than IIp. Highly similar cluster IIp RISA profiles were obtained from two patients harboring isolates of a same P. aeruginosa clone, suggesting convergent evolution in the structure of their microbiota. CF patients of cluster IIp had received significantly less antibiotics than patients of clusters Ip and IIIp but harbored the most resistant P. aeruginosa strains. Patients of cluster IIIp were older than those of Ip. The effects of P. aeruginosa on the RISA structures could not be fully dissociated from the above two confounding factors but several trends in these datasets support the conclusion of a strong incidence of P. aeruginosa on the genetic structure of CF lung microbiota.

  3. Evolved resistance to colistin and its loss due to genetic reversion in Pseudomonas aeruginosa

    OpenAIRE

    Ji-Young Lee; Young Kyoung Park; Eun Seon Chung; In Young Na; Kwan Soo Ko

    2016-01-01

    The increased reliance on colistin for treating multidrug-resistant Gram-negative bacterial infections has resulted in the emergence of colistin-resistant Pseudomonas aeruginosa. We attempted to identify genetic contributors to colistin resistance in vitro evolved isogenic colistin-resistant and -susceptible strains of two P. aeruginosa lineages (P5 and P155). Their evolutionary paths to acquisition and loss of colistin resistance were also tracked. Comparative genomic analysis revealed 13 an...

  4. Mature Pseudomonas aeruginosa biofilms prevail compared to young biofilms in the presence of ceftazidime.

    Science.gov (United States)

    Bowler, Laura L; Zhanel, George G; Ball, T Blake; Saward, Laura L

    2012-09-01

    Phenotypic tolerances to antibiotics of mature and young Pseudomonas aeruginosa PAO1 biofilms and released planktonic bacteria were compared for four antibiotics. Resistance levels were similar for gentamicin and ciprofloxacin but differed for ceftazidime and meropenem. β-Lactamase mapping showed that, after 5 h of ceftazidime exposure, mature biofilms produced more β-lactamase than young biofilms, facilitating the growth of released planktonic bacteria. This shows the importance of early treatment and choice of antibiotics for P. aeruginosa biofilm infections.

  5. Evaluation of antibiotic effects on Pseudomonas aeruginosa biofilm using Raman spectroscopy and multivariate analysis

    OpenAIRE

    Jung, Gyeong Bok; Nam, Seong Won; Choi, Samjin; Lee, Gi-Ja; Park, Hun-Kuk

    2014-01-01

    We investigate the mode of action and classification of antibiotic agents (ceftazidime, patulin, and epigallocatechin gallate; EGCG) on Pseudomonas aeruginosa (P. aeruginosa) biofilm using Raman spectroscopy with multivariate analysis, including support vector machine (SVM) and principal component analysis (PCA). This method allows for quantitative, label-free, non-invasive and rapid monitoring of biochemical changes in complex biofilm matrices with high sensitivity and specificity. In this s...

  6. Genetic diversity of clinical Pseudomonas aeruginosa isolates in a public hospital in Spain

    OpenAIRE

    Gomila, Margarita; del Carmen Gallegos, Maria; Fernández-Baca, Victoria; Pareja, Antonio; Pascual, Margalida; Díaz-Antolín, Paz; García-Valdés, Elena; Lalucat, Jorge

    2013-01-01

    Abstract Background Pseudomonas aeruginosa is an important nosocomial pathogen that exhibits multiple resistances to antibiotics with increasing frequency, making patient treatment more difficult. The aim of the study is to ascertain the population structure of this clinical pathogen in the Hospital Son Llàtzer, Spain. Results A significant set (56) of randomly selected clinical P. aeruginosa isolates, including multidrug and non-multidrug resistant isolates, were assigned to sequence types (...

  7. Identification of Genes Involved in Pseudomonas aeruginosa Biofilm-Specific Resistance to Antibiotics

    OpenAIRE

    Zhang, Li; Fritsch, Meredith; Hammond, Lisa; Landreville, Ryan; Slatculescu, Cristina; Colavita, Antonio; Mah, Thien-Fah

    2013-01-01

    Pseudomonas aeruginosa is a key opportunistic pathogen characterized by its biofilm formation ability and high-level multiple antibiotic resistance. By screening a library of random transposon insertion mutants with an increased biofilm-specifc antibiotic susceptibility, we previously identified 3 genes or operons of P. aeruginosa UCBPP-PA14 (ndvB, PA1875-1877 and tssC1) that do not affect biofilm formation but are involved in biofilm-specific antibiotic resistance. In this study, we demonstr...

  8. Extracellular Signals of a Human Epithelial Colorectal Adenocarcinoma (Caco-2) Cell Line Facilitate the Penetration of Pseudomonas aeruginosa PAO1 Strain through the Mucin Layer.

    Science.gov (United States)

    Hayashi, Naoki; Yokotani, Atsushi; Yamamoto, Masami; Kososhi, Mariko; Morita, Mayu; Fukunishi, Chiaki; Nishizawa, Nagisa; Gotoh, Naomasa

    2017-01-01

    Pseudomonas aeruginosa can penetrate the layer of mucus formed by host intestinal epithelial cells, often resulting in sepsis in immunocompromised patients. We have previously demonstrated that P. aeruginosa can penetrate the mucin layer by flagellar motility and the degradation of the mucin layer. However, it remains unclear how P. aeruginosa initially recognizes epithelial cells. Using the human epithelial colorectal adenocarcinoma (Caco-2) cell line, we investigated extracellular signaling that could facilitate the penetration of P. aeruginosa through the mucin layer. The supernatant from Caco-2 cell cultures increased penetration of P. aeruginosa through an artificial mucin layer. The Caco-2 cell supernatant increased bacterial flagella-dependent swarming motility, but it did not influence P. aeruginosa growth or protease activity. Filtering of the Caco-2 cell supernatant indicated that proteins weighing Caco-2 cell supernatant attracted P. aeruginosa cells. Finally, we identified that growth-regulated oncogene-α (GRO-α) secreted by Caco-2 cells was a factor facilitating flagellar filament rotation and swarming motility, although it did not attract the bacteria. We conclude that penetration of the mucin layer by P. aeruginosa is facilitated by small proteins (Caco-2 cells, both by inducing acceleration of flagellar motility and increasing chemotaxis.

  9. Potent Antibacterial Antisense Peptide-Peptide Nucleic Acid Conjugates Against Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Ghosal, Anubrata; Nielsen, Peter E

    2012-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen causing severe infections in hospital settings, especially with immune compromised patients, and the increasing prevalence of multidrug resistant strains urges search for new drugs with novel mechanisms of action. In this study we introduce...... antisense peptide-peptide nucleic acid (PNA) conjugates as antibacterial agents against P. aeruginosa. We have designed and optimized antisense peptide-PNA conjugates targeting the translation initiation region of the ftsZ gene (an essential bacterial gene involved in cell division) or the acpP gene (an...... significantly reduced bacterial survival. These results open the possibility of development of antisense antibacterials for treatment of Pseudomonas infections....

  10. Clinical utilization of genomics data produced by the international Pseudomonas aeruginosa consortium

    DEFF Research Database (Denmark)

    Freschi, Luca; Jeukens, Julie; Kukavica-Ibrulj, Irena

    2015-01-01

    major groups that are further divided into subgroups, some not previously reported in the literature. We also provide the first snapshot of P. aeruginosa strain diversity with respect to antibiotic resistance. Our approach will allow us to draw potential links between environmental strains and those......The International Pseudomonas aeruginosa Consortium is sequencing over 1000 genomes and building an analysis pipeline for the study of Pseudomonas genome evolution, antibiotic resistance and virulence genes. Metadata, including genomic and phenotypic data for each isolate of the collection...

  11. ECTHYMA GANGRENOSUM AND SEPTIC SHOCK CAUSED BY PSEUDOMONAS AERUGINOSA IN A CYTOTOXIC NEUTROPENIC PATIENT

    Directory of Open Access Journals (Sweden)

    I. A. Kurmukov

    2017-01-01

    Full Text Available Pseudomonas aeruginosa is an extremely dangerous cause of sepsis in patients with antitumor chemotherapyassociated neutropenia. Sometimes, the source of infection may be localized lesions of the skin (e.g. folliculitis or its derivatives, which are not of particular concern in the absence of neutropenia. The appearance of Ecthyma gangrenosum in a patient with neutropenia, even in the absence of any signs or symptoms of sepsis, requires emergency care and the appointment of antibiotics with high antipseudomonal activity. We are report the case of the complications of chemotherapy with the sequential development of Ecthyma gangrenosum and Pseudomonas aeruginosa septicemia in a patient with concomitant skin infection (folliculitis.

  12. Antimicrobial Resistance and Molecular Typing of Pseudomonas Aeruginosa Isolated from Surgical Wounds in Lagos, Nigeria

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    Kehinde Akinsinde

    2012-06-01

    Full Text Available The aim of the study was to determine the resistance patterns of Pseudomonas aeruginosa isolates recovered from patients with surgical wounds in hospitals and also to investigate their epidemiological relatedness using molecular typing techniques. Twenty Pseudomonas sp. isolated from surgical wounds were subjected to antibiotic susceptibility testing by disk diffusion, plasmid profile, SDS-PAGE and PCR using the parC, gyr A gene and RAPD using the 1254 primer. The isolates showed resistance to 12 different antibiotics with six being 100% resistant. Plasmids were detected in 16 (80% of the isolates. The RAPD-PCR using the primer 1254, SDS-PAGE classified the 20 Pseudomonas spp. into 5 and 6 types respectively. Pseudomona aeruginosa strains isolated from surgical wounds were generally resistant to a broad range of antibiotics and this is rather worrisome. The typing techniques classified the 20 isolates into 5 and 6 groups.

  13. Antimicrobial resistance and molecular typing of pseudomonas aeruginosa isolated from surgical wounds in Lagos, Nigeria.

    Science.gov (United States)

    Smith, Stella; Ganiyu, Olaniyi; John, Rachael; Fowora, Muinah; Akinsinde, Kehinde; Odeigah, Peter

    2012-01-01

    The aim of the study was to determine the resistance patterns of Pseudomonas aeruginosa isolates recovered from patients with surgical wounds in hospitals and also to investigate their epidemiological relatedness using molecular typing techniques. Twenty Pseudomonas sp. isolated from surgical wounds were subjected to antibiotic susceptibility testing by disk diffusion, plasmid profile, SDS-PAGE and PCR using the parC, gyr A gene and RAPD using the 1254 primer. The isolates showed resistance to 12 different antibiotics with six being 100% resistant. Plasmids were detected in 16 (80%) of the isolates. The RAPD-PCR using the primer 1254, SDS-PAGE classified the 20 Pseudomonas spp. into 5 and 6 types respectively. Pseudomona aeruginosa strains isolated from surgical wounds were generally resistant to a broad range of antibiotics and this is rather worrisome. The typing techniques classified the 20 isolates into 5 and 6 groups.

  14. Pseudomonas aeruginosa multiresistente em unidade de cuidados intensivos: desafios que procedem? Pseudomonas aeruginosa multiresistente en una unidad de cuidados intensivos: desafíos que proceden? Multi-resistant pseudomonas aeruginosa among patients from an intensive care unit: persistent challenge?

    Directory of Open Access Journals (Sweden)

    Maria Verônica Guilherme Ferrareze

    2007-03-01

    Full Text Available OBJETIVOS: Avaliar a ocorrência de infecção hospitalar por Pseudomonas aeruginosa multiresistente em pacientes hospitalizados em uma unidade de cuidados intensivos. MÉTODO: estudo retrospectivo realizado de outubro de 2003 a setembro de 2004 em um hospital de emergências. RESULTADOS: Totalizou-se 68 portadores de bactérias multiresistentes sendo 10 (14,7% de P. aeruginosa. Destes, 8 pacientes eram do sexo masculino, as médias de idade e de internação foram respectivamente de 57 anos a média de idade, 43,7 a média de dias de internação e 7 pacientes morreram. Isolaram-se 8 cepas no sangue, cinco na urina, duas em cateteres venosos e uma no líquor, das quais sete sensíveis somente a polimixina e três ao imipenem. CONCLUSÃO: O perfil microbiológico deve ser avaliado periodicamente visto que é específico de uma unidade ou instituição, e demanda ações correlatas.OBJETIVOS: Evaluar la ocurrencia de infección hospitalaria por Pseudomonas aeruginosa multiresistente en pacientes hospitalizados en una unidad de cuidados intensivos. MÉTODO: estudio retrospectivo realizado de octubre del 2003 a setiembre del 2004 en un hospital de emergencias. RESULTADOS: Se tuvo un total de 68 portadores de bacterias multiresistentes de las cuales 10 (14,7% de P. aeruginosa. De éstos, 8 pacientes eran del sexo masculino, los promedios de edad y de internamiento fueron respectivamente de 57 años y 43,7 de días de internamiento y 7 pacientes murieron. Se aislaron 8 cepas en la sangre, cinco en la orina, dos en catéteres venosos y una en el licor, de ellas siete eran sensibles sólo a la polimixina y tres al imipenem. CONCLUSIÓN: El perfil microbiológico debe ser evaluado periódicamente dado que es específico de una unidad o institución, y demanda acciones correlatas.OBJECTIVES: To evaluate the occurrence of multi-resistant Pseudomonas Aeruginosa infection among patients from an Intensive Care Unit. METHODS: This retrospective study was

  15. Nitrogen Source Stabilization of Quorum Sensing in the Pseudomonas aeruginosa Bioaugmentation Strain SD-1.

    Science.gov (United States)

    Wang, Mei-Zhen; Lai, Bai-Min; Dandekar, Ajai A; Yang, Yu-Sheng; Li, Na; Yin, Jun; Shen, Dong-Sheng

    2017-08-15

    Pseudomonas aeruginosa SD-1 is efficient at degrading aromatic compounds and can therefore contribute to the bioremediation of wastewater. P. aeruginosa uses quorum sensing (QS) to regulate the production of numerous secreted "public goods." In wastewater bioaugmentation applications, there are myriad nitrogen sources, and we queried whether various nitrogen sources impact the stabilities of both QS and the bacterial populations. In a laboratory strain of P. aeruginosa, PAO1, the absence of a nitrogen source has been shown to destabilize these populations through the emergence of QS mutant "cheaters." We tested the ability of SD-1 to grow in casein broth, a condition that requires QS for growth, when the nitrogen source with either NH4Cl, NaNO3, or NaNO2 or with no added nitrogen source. There was great variability in susceptibility to invasion by QS mutant cheaters and, by extension, the stability of the SD-1 population. When grown with NH4Cl as an extra nitrogen source, no population collapse was observed; by contrast, two-thirds of cultures grown in the presence of NaNO2 collapsed. In the populations that collapsed, the frequency of social cheaters exceeded 40%. NaNO3 and NaNO2 directly favor QS mutants of P. aeruginosa SD-1. Although the mechanism by which these nitrogen sources act is not clear, these data indicate that the metabolism of nitrogen can affect the stability of bacterial populations, an important observation for continuing industrial applications with this species.IMPORTANCE Bioaugmentation as a method to help remediate wastewater pollutant streams holds significant potential to enhance traditional methods of treatment. Addition of microbes that can catabolize organic pollutants can be an effective method to remove several toxic compounds. Such bioaugmented strains of bacteria have been shown to be susceptible to competition from the microbiota that are present in wastewater streams, limiting their potential effectiveness. Here, we show that

  16. Major Transcriptome Changes Accompany the Growth of Pseudomonas aeruginosa in Blood from Patients with Severe Thermal Injuries.

    Directory of Open Access Journals (Sweden)

    Cassandra Kruczek

    Full Text Available Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes serious infections in immunocompromised hosts including severely burned patients. After multiplying within the burn wound, P. aeruginosa translocate into the bloodstream causing bacterial sepsis frequently leading to organ dysfunction and septic shock. Although the pathogenesis of P. aeruginosa infection of thermally-injured wounds has been extensively analyzed, little is known regarding the ability of P. aeruginosa to adapt and survive within the blood of severely burned patients during systemic infection. To identify such adaptations, transcriptome analyses (RNA-seq were conducted on P. aeruginosa strain PA14 that was grown in whole blood from a healthy volunteer or three severely burned patients. Compared with growth in blood from healthy volunteers, growth of PA14 in the blood from severely burned patients significantly altered the expression of 2596 genes, with expression of 1060 genes enhanced, while that of 1536 genes was reduced. Genes whose expression was significantly reduced included genes related to quorum sensing, quorum sensing-controlled virulence factors and transport of heme, phosphate, and phosphonate. Genes whose expression was significantly enhanced were related to the type III secretion system, the pyochelin iron-acquisition system, flagellum synthesis, and pyocyanin production. We confirmed changes in expression of many of these genes using qRT-PCR. Although severe burns altered the levels of different blood components in each patient, the growth of PA14 in their blood produced similar changes in the expression of each gene. These results suggest that, in response to changes in the blood of severely burned patients and as part of its survival strategy, P. aeruginosa enhances the expression of certain virulence genes and reduces the expression of others.

  17. Post-transcriptional regulation of gene PA5507 controls PQS concentration in Pseudomonas aeruginosa

    OpenAIRE

    Tipton, Kyle A.; Coleman, James P.; Pesci, Everett C.

    2015-01-01

    Pseudomonas aeruginosa can sense and respond to a myriad of environmental signals and utilizes a system of small molecules to communicate through intercellular signaling. The small molecule 2-heptyl-3-hydroxy-4-quinolone (Pseudomonas Quinolone Signal [PQS]) is one of these signals and its synthesis is important for virulence. Previously, we identified an RpiR-type transcriptional regulator, QapR, that positively affects PQS production by repressing the qapR operon. An in-frame deletion of thi...

  18. Interference of Pseudomonas aeruginosa signalling and biofilm formation for infection control

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Tolker-Nielsen, Tim; Høiby, Niels

    2010-01-01

    Pseudomonas aeruginosa is the best described bacterium with regards to quorum sensing (QS), in vitro biofilm formation and the development of antibiotic tolerance. Biofilms composed of P. aeruginosa are thought to be the underlying cause of many chronic infections, including those in wounds...... and in the lungs of patients with cystic fibrosis. In this review, we provide an overview of the molecular mechanisms involved in QS, QS-enabled virulence, biofilm formation and biofilm-enabled antibiotic tolerance. We now have substantial knowledge of the multicellular behaviour of P. aeruginosa in vitro. A major...

  19. Whole genome sequence of Pseudomonas aeruginosa F9676, an antagonistic bacterium isolated from rice seed.

    Science.gov (United States)

    Shi, Zhenyuan; Ren, Deyong; Hu, Shikai; Hu, Xingming; Wu, Liwen; Lin, Haiyan; Hu, Jiang; Zhang, Guangheng; Guo, Longbiao

    2015-10-10

    Pseudomonas aeruginosa is a group of bacteria, which can be isolated from diverse ecological niches. P. aeruginosa strain F9676 was first isolated from a rice seed sample in 2003. It showed strong antagonism against several plant pathogens. In this study, whole genome sequencing was carried out. The total genome size of F9676 is 6368,008bp with 5586 coding genes (CDS), 67 tRNAs and 3 rRNAs. The genome sequence of F9676 may shed a light on antagonism P. aeruginosa. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Characterization of a novel Pseudomonas aeruginosa bacteriophage, KPP25, of the family Podoviridae.

    Science.gov (United States)

    Miyata, Reina; Yamaguchi, Kotoe; Uchiyama, Jumpei; Shigehisa, Ryu; Takemura-Uchiyama, Iyo; Kato, Shin-ichiro; Ujihara, Takako; Sakaguchi, Yoshihiko; Daibata, Masanori; Matsuzaki, Shigenobu

    2014-08-30

    Pseudomonas aeruginosa phages belonging to the family Podoviridae are one of the well-characterized phage groups. In this study, a novel P. aeruginosa phage, KPP25, was isolated and characterized. Phage KPP25's morphology was indicative of the family Podoviridae; however, analyses of the whole genome and the virion proteins suggested that it did not belong to any of the known podophage genera. Based on these analyses, phage KPP25 appears to be a novel podophage infecting P. aeruginosa. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Garlic blocks quorum sensing and promotes rapid clearing of pulmonary Pseudomonas aeruginosa infections

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, Peter Østrup; Rasmussen, Thomas B

    2005-01-01

    The opportunistic human pathogen Pseudomonas aeruginosa is the predominant micro-organism of chronic lung infections in cystic fibrosis patients. P. aeruginosa colonizes the lungs by forming biofilm microcolonies throughout the lung. Quorum sensing (QS) renders the biofilm bacteria highly tolerant......-treated biofilm. Garlic extract was administered as treatment for a mouse pulmonary infection model. Mice were treated with garlic extract or placebo for 7 days, with the initial 2 days being prophylactic before P. aeruginosa was instilled in the left lung of the mice. Bacteriology, mortality, histopathology...... and phagocytosis by PMNs, as well as leading to an improved outcome of pulmonary infections....

  2. Ap-PCR typing of carbapenem sensitive Pseudomonas aeruginosa ...

    African Journals Online (AJOL)

    In this study the antibiotic susceptibility of 51 P. aeruginosa strains isolated from clinical samples were detected by the disc diffusion test. The susceptibility of P. aeruginosa strains were found as respectively 55% amicacin, 43% aztreonam, 75% netilmycin, 68% sefepim, 73% ceftazidim, 76% ciproflaxacin, 37% gentamicin, ...

  3. Dynamics and spatial distribution of beta-lactamase expression in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Bagge, N.; Hentzer, Morten; Andersen, Jens Bo

    2004-01-01

    The development of resistance to beta-lactam antibiotics is a problem in the treatment of chronic Pseudomonas aeruginosa infection in the lungs of patients with cystic fibrosis. The main resistance mechanism is high-level expression of the chromosomally encoded AmpC beta-lactamase of P. aeruginosa...... of the ampC promoter to gfp(ASV) encoding an unstable version of the green fluorescent protein. In vitro biofilms of P. aeruginosa were exposed to the beta-lactam antibiotics imipenem and ceftazidime. Sub-MICs of imipenem significantly induced the monitor system of the biofilm bacteria in the peripheries...... distributions of beta-lactamase induction in P. aeruginosa cells growing in biofilms. Thus, our experiments show that P. aeruginosa cells growing in biofilms constitute a heterogeneous population unit which may create different antibiotic-selective environments for the bacteria in the biofilm....

  4. Epidemiology of Pseudomonas aeruginosa in cystic fibrosis and the possible role of contamination by dental equipment

    DEFF Research Database (Denmark)

    Jensen, E T; Giwercman, B; Ojeniyi, B

    1997-01-01

    Cystic fibrosis (CF) patients often suffer from Pseudomonas aeruginosa lung infection yet the source of this organism is not known. In order to determine whether CF patients might be contaminated with P. aeruginosa from dental equipment, a total of 103 water samples from 25 dental sessions...... in Frederiksberg Municipal Oral Health Care Service were examined. Three samples (2.9%) were positive for P. aeruginosa. Three hundred and twenty-seven water samples from 82 dental sessions from various other Municipal Oral Health Services in Denmark, attended by CF patients, were also examined. Eighteen of 327...... samples (5.5%) from nine sessions (11%) were positive for P. aeruginosa. In one case, genotypically identical (RFLP, pulsed-field gel electrophoresis) P. aeruginosa strains were found both in water from the dental equipment and in the CF patients sputum. This indicates a small risk for acquiring P...

  5. Accelerated corrosion of 2205 duplex stainless steel caused by marine aerobic Pseudomonas aeruginosa biofilm.

    Science.gov (United States)

    Xu, Dake; Xia, Jin; Zhou, Enze; Zhang, Dawei; Li, Huabing; Yang, Chunguang; Li, Qi; Lin, Hai; Li, Xiaogang; Yang, Ke

    2017-02-01

    Microbiologically influenced corrosion (MIC) of 2205 duplex stainless steel (DSS) in the presence of Pseudomonas aeruginosa was investigated through electrochemical and surface analyses. The electrochemical results showed that P. aeruginosa significantly reduced the corrosion resistance of 2205 DSS. Confocal laser scanning microscopy (CLSM) images showed that the depths of the largest pits on 2205 DSS with and without P. aeruginosa were 14.0 and 4.9μm, respectively, indicating that the pitting corrosion was accelerated by P. aeruginosa. X-ray photoelectron spectroscopy (XPS) results revealed that CrO 3 and CrN formed on the 2205 DSS surface in the presence of P. aeruginosa. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Evaluation of Enoyl-Acyl Carrier Protein Reductase Inhibitors as Pseudomonas aeruginosa Quorum-Quenching Reagents

    Directory of Open Access Journals (Sweden)

    Søren Molin

    2010-02-01

    Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen which is responsible for a wide range of infections. Production of virulence factors and biofilm formation by P. aeruginosa are partly regulated by cell-to-cell communication quorum-sensing systems. Identification of quorum-quenching reagents which block the quorum-sensing process can facilitate development of novel treatment strategies for P. aeruginosa infections. We have used molecular dynamics simulation and experimental studies to elucidate the efficiencies of two potential quorum-quenching reagents, triclosan and green tea epigallocatechin gallate (EGCG, which both function as inhibitors of the enoyl-acyl carrier protein (ACP reductase (ENR from the bacterial type II fatty acid synthesis pathway. Our studies suggest that EGCG has a higher binding affinity towards ENR of P. aeruginosa and is an efficient quorum-quenching reagent. EGCG treatment was further shown to be able to attenuate the production of virulence factors and biofilm formation of P. aeruginosa.

  7. Insights into the respiratory tract microbiota of patients with cystic fibrosis during early Pseudomonas aeruginosa colonization

    Energy Technology Data Exchange (ETDEWEB)

    Keravec, Marlene; Mounier, Jerome; Prestat , Emmanuel; Vallet, Sophie; Jansson, Janet K.; Bergaud , Gaetaqn; Rosec, Silvain; Gourious, Stephanie; Rault, Gilles; Coton, Emmanuel; Barbier, George; Hery-Arnaud, Geneveieve

    2015-08-09

    Abstract Pseudomonas aeruginosa plays a major role in cystic fibrosis (CF) progression. Therefore, it is important to understand the initial steps of P. aeruginosa infection. The structure and dynamics of CF respiratory tract microbial communities during the early stages of P. aeruginosa colonization were characterized by pyrosequencing and cloning-sequencing. The respiratory microbiota showed high diversity, related to the young age of the CF cohort (mean age 10 years). Wide inter- and intra-individual variations were revealed. A common core microbiota of 5 phyla and 13 predominant genera was found, the majority of which were obligate anaerobes. A few genera were significantly more prevalent in patients never infected by P. aeruginosa. Persistence of an anaerobic core microbiota regardless of P. aeruginosa status suggests a major role of certain anaerobes in the pathophysiology of lung infections in CF. Some genera may be potential biomarkers of pulmonary infection state.

  8. Genetic characterization of Pseudomonas aeruginosa-resistant isolates at the university teaching hospital in Iran.

    Science.gov (United States)

    Fazeli, Hossein; Sadighian, Hooman; Esfahani, Bahram Nasr; Pourmand, Mohammad Reza

    2015-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that is commonly responsible for nosocomial infections. The aim of this study was to perform a genotyping analysis of the Pseudomonas aeruginosa-resistant isolates by the multilocus sequence typing (MLST) method at the university teaching hospital in Iran. Antimicrobial susceptibility was analyzed for P. aeruginosa isolates. Ceftazidime-resistant (CAZres) isolates with a positive double-disc synergy test were screened for the presence of extended-spectrum β-lactamase-encoding genes. Phenotypic tests to detect the metallo-β-lactamase strains of P. aeruginosa were performed on imipenem-resistant (IMPres) isolates. Selected strains were characterized by MLST. Of 35 P. aeruginosa isolates, 71%, 45% and 45% of isolates were CAZres, IMPres and multidrug resistant (MDR), respectively. Fifty-seven percent of the isolates carried the bla OXAgroup-1. All the five typed isolates were ST235. Isolates of ST235 that were MDR showed a unique resistance pattern. This study shows a high rate of MDR P. aeruginosa isolates at the university teaching hospital in Iran. It seems MDR isolates of P. aeruginosa ST235 with unique resistance pattern disseminated in this hospital.

  9. Characterization of Virulence Potential of Pseudomonas Aeruginosa Isolated from Bovine Meat, Fresh Fish, and Smoked Fish.

    Science.gov (United States)

    Benie, Comoé Koffi Donatien; Dadié, Adjéhi; Guessennd, Nathalie; N'gbesso-Kouadio, Nadège Ahou; Kouame, N'zebo Désiré; N'golo, David Coulibaly; Aka, Solange; Dako, Etienne; Dje, Koffi Marcellin; Dosso, Mireille

    2017-03-01

    Pseudomonas aeruginosa owns a variability of virulence factors. These factors can increase bacterial pathogenicity and infection severity. Despite the importance of knowledge about them, these factors are not more characterized at level of strains derived from local food products. This study aimed to characterize the virulence potential of P. aeruginosa isolated from various animal products. Several structural and virulence genes of P. aeruginosa including lasB, exoS, algD, plcH, pilB, exoU, and nan1 were detected by polymerase chain reaction (PCR) on 204 strains of P. aeruginosa. They were isolated from bovine meat (122), fresh fish (49), and smoked fish (33). The 16S rRNA gene was detected on 91.1% of the presumptive strains as Pseudomonas. The rpoB gene showed that 99.5% of the strains were P. aeruginosa. The lasB gene (89.2%) was the most frequently detected (p aeruginosa serogroups O11 and O16. The prevalence of algD, exoS, and exoU genes in these strains varied from 51.2% to 87.4%. The simultaneous determination of serogroups and virulence factors is of interest for the efficacy of surveillance of infections associated with P. aeruginosa.

  10. Catheter-related infections caused by Pseudomonas aeruginosa: virulence factors involved and their relationships.

    Science.gov (United States)

    Olejnickova, Katerina; Hola, Veronika; Ruzicka, Filip

    2014-11-01

    The nosocomial pathogen Pseudomonas aeruginosa is equipped with a large arsenal of cell-associated and secreted virulence factors which enhance its invasive potential. The complex relationships among virulence determinants have hitherto not been fully elucidated. In the present study, 175 catheter-related isolates were observed for the presence of selected virulence factors, namely extracellular enzymes and siderophore production, biofilm formation, resistance to antibiotics, and motility. A high percentage of the strains produced most of the tested virulence factors. A positive correlation was identified between the production of several exoproducts, and also between the formation of both types of biofilm. An opposite trend was observed between the two types of biofilm and the production of siderophores. Whereas the relationship between the submerged biofilm production (i.e. the biofilm formed on the solid surface below the water level) and the siderophore secretion was negative, the production of air-liquid interface (A-L) biofilm (i.e. the biofilm floating on the surface of the cultivation medium) and the siderophore secretion were positively correlated. All correlations were statistically significant at the level P = 0.05 with the correlation coefficient γ ≥ 0.50. Our results suggest that: (1) the co-production of the lytic enzymes and siderophores can play an important role in the pathogenesis of the catheter-related infections and should be taken into account when the virulence potential is assessed; (2) biofilm-positive strains are capable of forming both submerged and non-attached A-L biofilms; and (3) the different micro-environment in the submerged biofilm and A-L biofilm layers have opposite consequences for the production of other virulence factors. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  11. Antimicrobial susceptibilities and clinical characterization of Pseudomonas aeruginosa isolates from urinary tract infections.

    Science.gov (United States)

    Zhang, Xiaobing; Niu, Siqiang; Zhang, Liping

    2014-01-01

    Pseudomonas aeruginosa is a uropathogen that is mainly involved in nosocomial infection. The aim of this study was to analyze the antimicrobial susceptibilities and clinical characterization of P. aeruginosa isolates from urinary tract infections (UTIs). The study collected all P. aeruginosa UTI strains from a hospital in Chongqing, China, from January 1st, 2010 to December 31st, 2011. The antibiotic susceptibilities of the P. aeruginosa isolates were analyzed using the agar dilution method and the genotypes were assessed using random amplification of polymorphic DNA-PCR (RAPD-PCR). The clinical characteristics of the patients with UTIs were collected from the hospital information systems, and significance was analyzed using the proportion test. A total of 2,778 episodes of culture-proven UTIs were used in the study. There were 198 infections (7.1%) caused by P. aeruginosa. P. aeruginosa strains were highly resistant to most drugs tested. The RAPD-PCR data revealed that the 198 P. aeruginosa infections had 82 different genotypes. Antibacterial use, previous UTI, urinary tract catheter and urinary tract operation were found to be risk factors for the development of UTIs. P. aeruginosa is the second most common UTI pathogen in our hospital. We should closely monitor patients with risk factors for P. aeruginosa infection.

  12. Extensively drug-resistant Pseudomonas aeruginosa bacteremia in solid organ transplant recipients.

    Science.gov (United States)

    Bodro, Marta; Sabé, Núria; Tubau, Fe; Lladó, Laura; Baliellas, Carme; González-Costello, José; Cruzado, Josep Maria; Carratalà, Jordi

    2015-03-01

    We sought to determine the risk factors, molecular epidemiology, antibiotic therapy, and outcomes of bacteremia because of extensively drug-resistant (XDR) Pseudomonas aeruginosa in solid organ transplant (SOT) recipients. All episodes of bacteremia occurring in SOT recipients were prospectively documented from 2007 to 2013. Of 318 episodes of bacteremia, 49 were caused by P. aeruginosa. Thirty-one strains (63%) were XDR defined by nonsusceptibility to at least one agent in all but two or fewer antipseudomonal antimicrobial categories. Time from transplantation to bacteremia was shorter in XDR P. aeruginosa group comparing to other etiologies (median days 66 vs. 278; P=0.03). Factors independently associated with XDR P. aeruginosa bacteremia were prior transplantation, nosocomial acquisition, and septic shock at onset. XDR P. aeruginosa isolates belonged to a single clone (ST-175). Comparing to other etiologies, patients with bacteremia because of XDR P. aeruginosa more often received inadequate empirical antibiotic therapy. Persistence of bacteremia, shock, respiratory failure and intensive care unit admission were more frequent in patients with XDR P. aeruginosa. The overall case-fatality rate was higher among patients with XDR P. aeruginosa bacteremia than in the others (38% vs. 16%; P=0.009). Bacteremia because of XDR P. aeruginosa should be carefully considered when selecting empirical antibiotic therapy for hospitalized SOT recipients with prior transplantation presenting with septic shock.

  13. Antimicrobial Susceptibility Pattern of Pseudomonas aeruginosa Isolated from Patients Referring to Hospitals

    Directory of Open Access Journals (Sweden)

    Zeynab Golshani

    2012-11-01

    Full Text Available Please cite this article as: Golshani Z, Ahadi AM, Sharifzadeh A. Antimicrobial Susceptibility Pattern of Pseudomonas aeruginosa Isolated from Patients Referring to Hospitals. Arch Hyg Sci 2012;1(2:48-53. Abstract: Background & Aims of the Study: The aim of this study was to detect and survey the antibiotic resistance pattern of Pseudomonas (P. aeruginosa isolated from patients in Isfahan (located in central Iran hospitals. Materials & Methods : A Total of 50 clinical isolates of P. aeruginosa were collected from urine, wound, trachea, ear swab, and pus, and then were confirmed by standard tests. Antibiotic susceptibility was determined by the Kirby-Bauer disc diffusion method. Susceptibility data were compared by chi-square test using SPSS version 15. Results: Among the isolated strains, resistance to oxacillin was seen in 100%, ceftriaxone in 76%, amikacin in 70%, ceftazidime in 68%, cefepime in 68%, tobramycin in 62%, gentamicin in 60%, ciprofloxacin in 58%, and imipenem in 58% of the isolates. Conclusions: Comparison of the results showed that, patterns of antibiotic resistance are different from one hospital to another in various areas. Therefore, it is suggested that such studies should be performed in different hospitals. Also, prescribing correct medications is essential to prevent further increases in resistant bacteria. References: 1. Pagani L, Mantengoli E, Migliavacca R, Nucleo E, Pollini S, Spalla M, et al. Multifocal Detection of Multidrug-Resistant Pseudomonas aeruginosa Producing the PER-1 Extended- Spectrum β-Lactamase in Northern Italy. J Clin Microbiol 2004;42(6:2523–9. 2. Ling TKW, Xiong J, Yu Y, Lee CC, Ye H, Hawkey PM, et al. Multicenter Antimicrobial Susceptibility Survey of Gram-Negative Bacteria Isolated from Patients with Community-Acquired Infections in the People's Republic of China. Antimicrob Agents Chemother 2006;50(1:374–8. 3. Gupta V, Datta P, Agnihotri N, Chander J. Comparative in vitro Activities of Seven

  14. Pseudomonas aeruginosa PAO1 exopolysaccharides are important for mixed species biofilm community development and stress tolerance.

    Science.gov (United States)

    Periasamy, Saravanan; Nair, Harikrishnan A S; Lee, Kai W K; Ong, Jolene; Goh, Jie Q J; Kjelleberg, Staffan; Rice, Scott A

    2015-01-01

    Pseudomonas aeruginosa PAO1 produces three polysaccharides, alginate, Psl, and Pel that play distinct roles in attachment and biofilm formation for monospecies biofilms. Considerably less is known about their role in the development of mixed species biofilm communities. This study has investigated the roles of alginate, Psl, and Pel during biofilm formation of P. aeruginosa in a defined and experimentally informative mixed species biofilm community, consisting of P. aeruginosa, Pseudomonas protegens, and Klebsiella pneumoniae. Loss of the Psl polysaccharide had the biggest impact on the integration of P. aeruginosa in the mixed species biofilms, where the percent composition of the psl mutant was significantly lower (0.06%) than its wild-type (WT) parent (2.44%). In contrast, loss of the Pel polysaccharide had no impact on mixed species biofilm development. Loss of alginate or its overproduction resulted in P. aeruginosa representing 8.4 and 18.11%, respectively, of the mixed species biofilm. Dual species biofilms of P. aeruginosa and K. pneumoniae were not affected by loss of alginate, Pel, or Psl, while the mucoid P. aeruginosa strain achieved a greater biomass than its parent strain. When P. aeruginosa was grown with P. protegens, loss of the Pel or alginate polysaccharides resulted in biofilms that were not significantly different from biofilms formed by the WT PAO1. In contrast, overproduction of alginate resulted in biofilms that were comprised of 35-40% of P. aeruginosa, which was significantly higher than the WT (5-20%). Loss of the Psl polysaccharide significantly reduced the percentage composition of P. aeruginosa in dual species biofilms with P. protegens (<1%). Loss of the Psl polysaccharide significantly disrupted the communal stress resistance of the three species biofilms. Thus, the polysaccharide composition of an individual species significantly impacts mixed species biofilm development and the emergent properties of such communities.

  15. Pseudomonas aeruginosa PAO1 exopolysaccharides are important for mixed species biofilm community development and stress tolerance

    Directory of Open Access Journals (Sweden)

    Saravanan ePeriasamy

    2015-08-01

    Full Text Available Pseudomonas aeruginosa PAO1 produces three polysaccharides, alginate, Psl and Pel that play distinct roles in attachment and biofilm formation for monospecies biofilms. Considerably less is known about their role in the development of mixed species biofilm communities. This study has investigated the roles of alginate, Psl and Pel during biofilm formation of P. aeruginosa in a defined and experimentally informative mixed species biofilm community, consisting of P. aeruginosa, Pseudomonas protegens and Klebsiella pneumoniae. Loss of the Psl polysaccharide had the biggest impact on the integration of P. aeruginosa in the mixed species biofilms, where the percent composition of the psl mutant was significantly lower (0.06% than its wild-type parent (2.44%. In contrast, loss of the Pel polysaccharide had no impact on mixed species biofilm development. Loss of alginate or its overproduction resulted in P. aeruginosa representing 8.4% and 18.11%, respectively, of the mixed species biofilm. Dual species biofilms of P. aeruginosa and K. pneumoniae were not affected by loss of alginate, Pel or Psl, while the mucoid P. aeruginosa strain achieved a greater biomass than its parent strain. When P. aeruginosa was grown with P. protegens, loss of the Pel or alginate polysaccharides resulted in biofilms that were not significantly different from biofilms formed by the wild-type PAO1. In contrast, overproduction of alginate resulted in biofilms that were comprised of 35-40% of P. aeruginosa, which was significantly higher than the wild-type (5-20%. Loss of the Psl polysaccharide significantly reduced the percentage composition of P. aeruginosa in dual species biofilms with P. protegens (<1%. Loss of the Psl polysaccharide significantly disrupted the communal stress resistance of the three species biofilms. Thus, the polysaccharide composition of an individual species significantly impacts mixed species biofilm development and the emergent properties of such

  16. The impact of nosocomially-acquired resistant Pseudomonas aeruginosa infection in a burn unit.

    Science.gov (United States)

    Armour, Alexis D; Shankowsky, Heather A; Swanson, Todd; Lee, Jonathan; Tredget, Edward E

    2007-07-01

    Nosocomially-acquired Pseudomonas aeruginosa remains a serious cause of infection and septic mortality in burn patients. This study was conducted to quantify the impact of nosocomially-transmitted resistant P. aeruginosa in a burn population. Using a TRACS burn database, 48 patients with P. aeruginosa resistant to gentamicin were identified (Pseudomonas group). Thirty-nine were case-matched to controls without resistant P. aeruginosa cultures (control group) for age, total body surface area, admission year, and presence of inhalation injury. Mortality and various morbidity endpoints were examined, as well as antibiotic costs. There was a significantly higher mortality rate in the Pseudomonas group (33% vs. 8%, p < 0.001) compared with in the control group. Length of stay was increased in the Pseudomonas group (73.4 +/- 11.6 vs. 58.3 +/- 8.3 days). Ventilatory days (23.9 +/- 5.4 vs. 10.8 +/- 2.4, p < 0.05), number of surgical procedures (5.2 +/- 0.6 vs. 3.4 +/- 0.4, p < 0.05), and amount of blood products used (packed cells 51.1 +/- 8.0 vs. 21.1 +/- 3.4, p < 0.01; platelets 11.9 +/- 3.0 vs. 1.4 +/- 0.7, p < 0.01) were all significantly higher in the Pseudomonas group. Cost of antibiotics was also significantly higher ($2,658.52 +/- $647.93 vs. $829.22 +/- $152.82, p < 0.01). Nosocomial colonization or infection, or both, of burn patients with aminoglycoside-resistant P. aeruginosa is associated with significantly higher morbidity, mortality, and cost of care. Increased resource consumption did not prevent significantly higher mortality rates when compared with that of control patients. Thus, prevention, identification, and eradication of nosocomial Pseudomonas contamination are critical for cost-effective, successful burn care.

  17. Structural insights into the effector-immunity system Tse1/Tsi1 from Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Juliane Benz

    Full Text Available During an interbacterial battle, the type-6-secretion-system (T6SS of the human pathogen Pseudomonas aeruginosa injects the peptidoglycan(PG-hydrolase Tse1 into the periplasm of gram-negative enemy cells and induces their lysis. However, for its own benefit, P. aeruginosa produces and transports the immunity-protein Tsi1 into its own periplasm where in prevents accidental exo- and endogenous intoxication. Here we present the high-resolution X-ray crystal structure of the lytic enzyme Tse1 and describe the mechanism by which Tse1 cleaves the γ-D-glutamyl-l-meso-diaminopimelic acid amide bond of crosslinked PG. Tse1 belongs to the superfamily of N1pC/P60 peptidases but is unique among described members of this family of which the structure was described, since it is a single domain protein without any putative localization domain. Most importantly, we present the crystal structure of Tse1 bound to its immunity-protein Tsi1 as well and describe the mechanism of enzyme inhibition. Tsi1 occludes the active site of Tse1 and abolishes its enzyme activity by forming a hydrogen bond to a catalytically important histidine residue in Tse1. Based on our structural findings in combination with a bioinfomatic approach we also identified a related system in Burkholderia phytofirmans. Not only do our findings point to a common catalytic mechanism of the Tse1 PG-hydrolases, but we can also show that it is distinct from other members of this superfamily. Furthermore, we provide strong evidence that the mechanism of enzyme inhibition between Tsi1 orthologues is conserved. This work is the first structural description of an entire effector/immunity pair injected by the T6SS system. Moreover, it is also the first example of a member of the N1pC/P60 superfamily which becomes inhibited upon binding to its cognate immunity protein.

  18. Virulence Factors of Pseudomonas aeruginosa Induce Both the Unfolded Protein and Integrated Stress Responses in Airway Epithelial Cells.

    Directory of Open Access Journals (Sweden)

    Emily F A van 't Wout

    2015-06-01

    Full Text Available Pseudomonas aeruginosa infection can be disastrous in chronic lung diseases such as cystic fibrosis and chronic obstructive pulmonary disease. Its toxic effects are largely mediated by secreted virulence factors including pyocyanin, elastase and alkaline protease (AprA. Efficient functioning of the endoplasmic reticulum (ER is crucial for cell survival and appropriate immune responses, while an excess of unfolded proteins within the ER leads to "ER stress" and activation of the "unfolded protein response" (UPR. Bacterial infection and Toll-like receptor activation trigger the UPR most likely due to the increased demand for protein folding of inflammatory mediators. In this study, we show that cell-free conditioned medium of the PAO1 strain of P. aeruginosa, containing secreted virulence factors, induces ER stress in primary bronchial epithelial cells as evidenced by splicing of XBP1 mRNA and induction of CHOP, GRP78 and GADD34 expression. Most aspects of the ER stress response were dependent on TAK1 and p38 MAPK, except for the induction of GADD34 mRNA. Using various mutant strains and purified virulence factors, we identified pyocyanin and AprA as inducers of ER stress. However, the induction of GADD34 was mediated by an ER stress-independent integrated stress response (ISR which was at least partly dependent on the iron-sensing eIF2α kinase HRI. Our data strongly suggest that this increased GADD34 expression served to protect against Pseudomonas-induced, iron-sensitive cell cytotoxicity. In summary, virulence factors from P. aeruginosa induce ER stress in airway epithelial cells and also trigger the ISR to improve cell survival of the host.

  19. Intestinal and Systemic Immune Responses upon Multi-drug Resistant Pseudomonas aeruginosa Colonization of Mice Harboring a Human Gut Microbiota

    Science.gov (United States)

    Eliane, von Klitzing; Ekmekciu, Ira; Bereswill, Stefan; Heimesaat, Markus M.

    2017-01-01

    The World Health Organization has rated multi-drug resistant (MDR) Pseudomonas aeruginosa as serious threat for human health. It is, however, unclear, whether intestinal MDR P. aeruginosa carriage is associated with inflammatory responses in intestinal or even systemic compartments. In the present study, we generated with respect to their microbiota “humanized” mice by human fecal microbiota transplantation of secondary abiotic mice. Following peroral challenge with a clinical P. aeruginosa isolate on two consecutive days, mice harboring a human or murine microbiota were only partially protected from stable intestinal P. aeruginosa colonization given that up to 78% of mice were P. aeruginosa-positive at day 28 post-infection (p.i.). Irrespective of the host-specificity of the microbiota, P. aeruginosa colonized mice were clinically uncompromised. However, P. aeruginosa colonization resulted in increased intestinal epithelial apoptosis that was accompanied by pronounced proliferative/regenerative cell responses. Furthermore, at day 7 p.i. increased innate immune cell populations such as macrophages and monocytes could be observed in the colon of mice harboring either a human or murine microbiota, whereas this held true at day 28 p.i. for adaptive immune cells such as B lymphocytes in both the small and large intestines of mice with murine microbiota. At day 7 p.i., pro-inflammatory cytokine secretion was enhanced in the colon and mesenteric lymph nodes, whereas the anti-inflammatory cytokine IL-10 was down-regulated in the former at day 28 p.i. Strikingly, cytokine responses upon intestinal P. aeruginosa colonization were not restricted to the intestinal tract, but could also be observed systemically, given that TNF and IFN-γ concentrations were elevated in spleens as early as 7 days p.i., whereas splenic IL-10 levels were dampened at day 28 p.i. of mice with human microbiota. In conclusion, mere intestinal carriage of MDR P. aeruginosa by clinically unaffected

  20. Intestinal and Systemic Immune Responses upon Multi-drug Resistant Pseudomonas aeruginosa Colonization of Mice Harboring a Human Gut Microbiota

    Directory of Open Access Journals (Sweden)

    von Klitzing Eliane

    2017-12-01

    Full Text Available The World Health Organization has rated multi-drug resistant (MDR Pseudomonas aeruginosa as serious threat for human health. It is, however, unclear, whether intestinal MDR P. aeruginosa carriage is associated with inflammatory responses in intestinal or even systemic compartments. In the present study, we generated with respect to their microbiota “humanized” mice by human fecal microbiota transplantation of secondary abiotic mice. Following peroral challenge with a clinical P. aeruginosa isolate on two consecutive days, mice harboring a human or murine microbiota were only partially protected from stable intestinal P. aeruginosa colonization given that up to 78% of mice were P. aeruginosa-positive at day 28 post-infection (p.i.. Irrespective of the host-specificity of the microbiota, P. aeruginosa colonized mice were clinically uncompromised. However, P. aeruginosa colonization resulted in increased intestinal epithelial apoptosis that was accompanied by pronounced proliferative/regenerative cell responses. Furthermore, at day 7 p.i. increased innate immune cell populations such as macrophages and monocytes could be observed in the colon of mice harboring either a human or murine microbiota, whereas this held true at day 28 p.i. for adaptive immune cells such as B lymphocytes in both the small and large intestines of mice with murine microbiota. At day 7 p.i., pro-inflammatory cytokine secretion was enhanced in the colon and mesenteric lymph nodes, whereas the anti-inflammatory cytokine IL-10 was down-regulated in the former at day 28 p.i. Strikingly, cytokine responses upon intestinal P. aeruginosa colonization were not restricted to the intestinal tract, but could also be observed systemically, given that TNF and IFN-γ concentrations were elevated in spleens as early as 7 days p.i., whereas splenic IL-10 levels were dampened at day 28 p.i. of mice with human microbiota. In conclusion, mere intestinal carriage of MDR P. aeruginosa by

  1. The effects of nickel(II) complexes with imidazole derivatives on pyocyanin and pyoverdine production by Pseudomonas aeruginosa strains isolated from cystic fibrosis.

    Science.gov (United States)

    Gałczyńska, Katarzyna; Kurdziel, Krystyna; Adamus-Białek, Wioletta; Wąsik, Sławomir; Szary, Karol; Drabik, Marcin; Węgierek-Ciuk, Aneta; Lankoff, Anna; Arabski, Michał

    2015-01-01

    Pseudomonas aeruginosa infection is problematic in patients with cystic fibrosis (CF). P. aeruginosa secretes a diversity of pigments, such as pyocyanin and pyoverdine. The aim of this study was to evaluate the effects of complexes of nickel(II) ([Ni(iaa)2(H2O)2]·H2O (iaa = imidazole-4-acetate anion), [Ni(1-allim)6](NO3)2 (1-allim = 1-allylimidazole) and NiCl2 on pyocyanin and pyoverdine production by 23 strains of P. aeruginosa isolated from cystic fibrosis under growth conditions specific for the CF respiratory system. The antibacterial effects and biophysical properties of the tested substances were measured by spectrofluorometric techniques, as well as by laser interferometry, confocal and atomic force microscopy. The cytotoxic properties of all compounds were measured by Annexin/IP assay against A549 cells. All tested compounds have no effect on pyocyanin production and decrease the pyoverdine secretion in about 40% of tested P. aeruginosa strains at non-cytotoxic range of concentrations. Imidazole-4-acetate anion and 1-allylimidazole have good diffusion properties in the mature P. aeruginosa PAO1 biofilm. In conclusion, the tested nickel(II) complexes do not have clinical implications in P. aeruginosa eradication in cystic fibrosis. The diffusion properties of 1-allylimidazole and imidazole-4-acetate and their lack of effect on A549 cells suggest that they might be considered for chemical synthesis with other transition metals.

  2. Pseudomonas aeruginosa phenotypes associated with eradication failure in children with cystic fibrosis.

    Science.gov (United States)

    Mayer-Hamblett, Nicole; Ramsey, Bonnie W; Kulasekara, Hemantha D; Wolter, Daniel J; Houston, Laura S; Pope, Christopher E; Kulasekara, Bridget R; Armbruster, Catherine R; Burns, Jane L; Retsch-Bogart, George; Rosenfeld, Margaret; Gibson, Ronald L; Miller, Samuel I; Khan, Umer; Hoffman, Lucas R

    2014-09-01

    Pseudomonas aeruginosa is a key respiratory pathogen in people with cystic fibrosis (CF). Due to its association with lung disease progression, initial detection of P. aeruginosa in CF respiratory cultures usually results in antibiotic treatment with the goal of eradication. Pseudomonas aeruginosa exhibits many different phenotypes in vitro that could serve as useful prognostic markers, but the relative relationships between these phenotypes and failure to eradicate P. aeruginosa have not been well characterized. We measured 22 easily assayed in vitro phenotypes among the baseline P. aeruginosa isolates collected from 194 participants in the 18-month EPIC clinical trial, which assessed outcomes after antibiotic eradication therapy for newly identified P. aeruginosa. We then evaluated the associations between these baseline isolate phenotypes and subsequent outcomes during the trial, including failure to eradicate after antipseudomonal therapy, emergence of mucoidy, and occurrence of an exacerbation. Baseline P. aeruginosa isolates frequently exhibited phenotypes thought to represent chronic adaptation, including mucoidy. Wrinkly colony surface and irregular colony edges were both associated with increased risk of eradication failure (hazard ratios [95% confidence intervals], 1.99 [1.03-3.83] and 2.14 [1.32-3.47], respectively). Phenotypes reflecting defective quorum sensing were significantly associated with subsequent mucoidy, but no phenotype was significantly associated with subsequent exacerbations during the trial. Pseudomonas aeruginosa phenotypes commonly considered to reflect chronic adaptation were observed frequently among isolates at early detection. We found that 2 easily assayed colony phenotypes were associated with failure to eradicate after antipseudomonal therapy, both of which have been previously associated with altered biofilm formation and defective quorum sensing. © The Author 2014. Published by Oxford University Press on behalf of the

  3. Ambroxol inhibits mucoid conversion of Pseudomonas aeruginosa and contributes to the bactericidal activity of ciprofloxacin against mucoid P. aeruginosa biofilms.

    Science.gov (United States)

    Wang, Wenlei; Yu, Jialin; He, Yu; Wang, Zhengli; Li, Fang

    2016-07-01

    Pseudomonas aeruginosa is an opportunistic human pathogen that can cause severe infections in immunocompromised individuals. Because it forms biofilms, which protect against host immune attack and increase resistance to conventional antibiotics, mucoid P. aeruginosa is nearly impossible to eradicate. Moreover, mucoid conversion of P. aeruginosa in cystic fibrosis (CF) patients leads to poor outcomes. This conversion is mainly due to mucA gene mutation, which is thought to be induced by polymorphonuclear leukocytes (PMNs) and the reactive oxygen species they release. Ambroxol, a mucolytic agent with antioxidant characteristics, is used clinically, and this compound has recently been demonstrated to possess anti-biofilm properties. In this study, we found that ambroxol inhibits the H2 O2 -mediated conversion of P. aeruginosa from a non-mucoid to a mucoid phenotype, an effect that is due to its antioxidant property against H2 O2 . Furthermore, the bactericidal activity of ciprofloxacin against mucoid P. aeruginosa biofilms was increased in vitro when used in combination with ambroxol. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  4. Pseudomonas aeruginosa biofilm formation and slime excretion on antibiotic-loaded bone cement

    NARCIS (Netherlands)

    Neut, D; Hendriks, JGE; van Horn, [No Value; van der Mei, HC; Busscher, HJ

    Background Infection is an infrequent but serious complication of prosthetic joint surgery. These infections will usually not clear until the implant is removed and re-implantation has a high failure rate, especially when Pseudomonas aeruginosa is involved. Material and methods We examined

  5. Anaerobic production of alginate by Pseudomonas aeruginosa: alginate restricts diffusion of oxygen.

    OpenAIRE

    Hassett, D J

    1996-01-01

    Pseudomonas aeruginosa produced alginate and elevated algD (encoding GDPmannose 6-dehydrogenase) transcription under strict anaerobic conditions, especially when using nitrate as a terminal electron acceptor. Purified alginate added to bacterial suspensions caused a decrease in growth, suggesting that alginate contributes to oxygen limitation for the organism and likely for patients afflicted with the inherited autosomal disease cystic fibrosis.

  6. In vivo pharmacokinetics/pharmacodynamics of colistin and imipenem in Pseudomonas aeruginosa biofilm infection

    DEFF Research Database (Denmark)

    Hengzhuang, Wang; Wu, Hong; Ciofu, Oana

    2012-01-01

    Many Pseudomonas aeruginosa isolates from the airways of patients with cystic fibrosis (CF) are sensitive to antibiotics in susceptibility testing, but eradication of the infection is difficult. The main reason is the biofilm formation in the airways of patients with CF. The pharmacokinetics (PKs...

  7. Recent advances in the treatment of Pseudomonas aeruginosa infections in cystic fibrosis

    DEFF Research Database (Denmark)

    Høiby, Niels

    2011-01-01

    exacerbations and sputum density of P. aeruginosa. Other drugs such as quinolones are currently under investigation for inhalation therapy. A trial of the use of anti-Pseudomonas antibiotics for long-term prophylaxis showed no effect in patients who were not already infected. Use of azithromycin to treat CF...

  8. Pyoverdine and PQS Mediated Subpopulation Interactions Involved in Pseudomonas aeruginosa Biofilm Formation

    DEFF Research Database (Denmark)

    Yang, Liang; Nilsson, Martin; Gjermansen, Morten

    2009-01-01

    Using flow chamber-grown Pseudomonas aeruginosa biofilms as model system, we show in the present study that formation of heterogeneous biofilms may occur through mechanisms that involve complex subpopulation interactions. One example of this phenomenon is expression of the iron...

  9. Antimicrobial potential of bioconverted products of omega-3 fatty acids by Pseudomonas aeruginosa PR3

    Science.gov (United States)

    Bioconverted omega-3 fatty acids, eicosapentaenoic acid (bEPA) and docosahexanoic acid (bDHA), obtained from the microbial conversion of non-bioconverted eicosapentaenoic and docosahexaenoic acids by Pseudomonas aeruginosa PR3 were evaluated for their antimicrobial potential. bEPA and bDHA at 5 µl/...

  10. CHARACTERIZATION OF PB2+ UPTAKE AND SEQUESTRATION IN PSEUDOMONAS AERUGINOSA CHL004

    Science.gov (United States)

    In laboratory studies, the soil isolate Pseudomonas aeruginosa CHL004 (Vesper et al 1996) has been found to concentrated Pb2+ in the cytoplasm by formation of particles that contain Pb2+ and phosphorus. Upon examination of the washed lyophilized cells grown in the presence of lea...

  11. CHARACTERIZATION OF PB2+ UPTAKE AND SEQUESTRATION IN PSEUDOMONAS AERUGINOSA, CHL004, LEAD

    Science.gov (United States)

    In laboratory studies, the soil isolate Pseudomonas aeruginosa CHL004 has been found to concentrate Pb2+ in the cytoplasm by formation of particles that contain Pb2+ and phosphorus. Upon examination of many particles using x-ray diffraction, we have found that the product formed ...

  12. Multiple roles of biosurfactants in structural biofilm development by Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Pamp, Sünje Johanna; Tolker-Nielsen, Tim

    2007-01-01

    Recent studies have indicated that biosurfactants produced by Pseudomonas aeruginosa play a role both in maintaining channels between multicellular structures in biofilms and in dispersal of cells from biofilms. Through the use of flow cell technology and enhanced confocal laser scanning microscopy...

  13. Systems Biology Investigations of Pseudomonas aeruginosa Evolution in Association with Human Airway Infections

    DEFF Research Database (Denmark)

    Pedersen, Søren Damkiær

    environments. The model system used for these investigations has been long-term chronic airway infections in Cystic fibrosis (CF) patients caused by the opportunistic pathogen Pseudomonas aeruginosa. Using a systems biology approach, we have monitored the adaptive development of the clinically important P...

  14. Experimental and Theoretical Investigation of Signaling in Quorum Sensing of Pseudomonas Aeruginosa

    DEFF Research Database (Denmark)

    Claussen, Anetta

    concentration) reaches a threshold value, after which the host system is surprised by a stealth attack. The focus of this study is on the Quorum Sensing regulatory system of Pseudomonas aeruginosa called the Las system. In this thesis, two distinct methods to obtain information about the system are considered...

  15. Inhibition of quorum sensing in Pseudomonas aeruginosa biofilm bacteria by a halogenated furanone compound

    DEFF Research Database (Denmark)

    Hentzer, Morten; Riedel, Kathrin; Rasmussen, Thomas B

    2002-01-01

    Novel molecular tools have been constructed which allow for in situ detection of N-acyl homoserine lactone (AHL)-mediated quorum sensing in Pseudomonas aeruginosa biofilms. The reporter responds to AHL activation of LasR by expression of an unstable version of the green-fluorescent protein (Gfp)....

  16. Pharmacokinetics/pharmacodynamics of colistin and imipenem on mucoid and nonmucoid Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Hengzhuang, Wang; Wu, Hong; Ciofu, Oana

    2011-01-01

    The time course of activity of colistin and imipenem against mucoid and nonmucoid Pseudomonas aeruginosa growing in a biofilm showed that compared with those for planktonic bacteria, the kinetics of colistin and imipenem retained the concentration- and time-dependent killing, respectively...

  17. Friend or foe: genetic and functional characterization of plant endophytic Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Kumar, A.; Munder, A.; Aravind, R.; Eapen, S.J.; Tümmler, B.; Raaijmakers, J.M.

    2013-01-01

    Endophytic Pseudomonas aeruginosa strain BP35 was originally isolated from black pepper grown in the rain forest in Kerala, India. Strain PaBP35 was shown to provide significant protection to black pepper against infections by Phytophthora capsici and Radopholus similis. For registration and

  18. Initial adhesion and surface growth of Staphylococcus epidermidis and Pseudomonas aeruginosa on biomedical polymers

    NARCIS (Netherlands)

    Gottenbos, B; van der Mei, HC; Busscher, HJ

    The infection risk of biomaterials implants varies between different materials and is determined by an interplay of adhesion and surface growth of the infecting organisms. In this study, we compared initial adhesion and surface growth of Staphylococcus epidermidis HBH2 102 and Pseudomonas aeruginosa

  19. Nonrandom distribution of Pseudomonas aeruginosa and Staphylococcus aureus in chronic wounds

    DEFF Research Database (Denmark)

    Fazli, Mustafa; Bjarnsholt, Thomas; Kirketerp-Møller, Klaus

    2009-01-01

    The spatial organization of Pseudomonas aeruginosa and Staphylococcus aureus in chronic wounds was investigated in the present study. Wound biopsy specimens were obtained from patients diagnosed as having chronic venous leg ulcers, and bacterial aggregates in these wounds were detected and located...

  20. Molecular monolayers and interfacial electron transfer of pseudomonas aeruginosa azurin on Au(111)

    DEFF Research Database (Denmark)

    Chi, Qijin; Zhang, Jingdong; Nielsen, Jens Ulrik

    2000-01-01

    We provide a comprehensive approach to the formation and characterization of molecular monolayers of the blue copper protein Pseudomonas aeruginosa azurin on Au(111) in aqueous ammonium acetate solution. Main issues are adsorption patterns, reductive desorption, properties of the double layer...

  1. Topological characterization and modeling of the 3D structure of lipase from Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Jaeger, Karl-Erich; Ransac, Stéphane; Koch, Heinrich B.; Ferrato, Francine; Dijkstra, Bauke W.

    1993-01-01

    Lipase from Pseudomonas aeruginosa is a M(r) 29 kDa protein with a single functional disulfide bond as shown by a shift in electrophoretic mobility after treatment with dithiothreitol and iodoacetamide. Limited proteolysis of lipase with Staphylococcus aureus protease V8 resulted in cleavage after

  2. Molecular cloning and characterization of the alkaline ceramidase from Pseudomonas aeruginosa PA01

    NARCIS (Netherlands)

    Nieuwenhuizen, W.F.; Leeuwen, S. van; Jack, R.W.; Egmond, M.R.; Götz, F.

    2003-01-01

    Ceramidase (CDase) hydrolyzes the amide bond in ceramides to yield free fatty acid and sphingosine. From a 3-L Pseudomonas aeruginosa PA01 culture, 70 μg of extracellular alkaline, Ca2+-dependent CDase, was purified to homogeneity, the N-terminal sequence was determined, and the CDase gene was

  3. N-acylhomoserine-lactone-mediated communication between Pseudomonas aeruginosa and Burkholderia cepacia in mixed biofilms

    DEFF Research Database (Denmark)

    Riedel, K.; Hentzer, Morten; Geisenberger, O.

    2001-01-01

    Pseudomonas aeruginosa and Burkholderia cepacia are capable of forming mixed biofilms in the lungs of cystic fibrosis patients. Both bacteria employ quorum-sensing systems, which rely on N-acylhomoserine lactone (AHL) signal molecules, to co- ordinate expression of virulence factors with the form...

  4. Quorum-Quenching Acylase Reduces the Virulence of Pseudomonas aeruginosa in a Caenorhabditis elegans Infection Model

    NARCIS (Netherlands)

    Papaioannou, Evelina; Wahjudi, Mariana; Nadal-Jimenez, Pol; Koch, Gudrun; Setroikromo, Rita; Quax, Wim J.

    2009-01-01

    The Pseudomonas aeruginosa PAO1 gene pvdQ encodes an acyl-homoserine lactone (AHL) acylase capable of degrading N-(3-oxododecanoyl)-L-homoserine lactone by cleaving the AHL amide. PvdQ has been proven to function as a quorum quencher in vitro in a number of phenotypic assays. To address the question

  5. Cell surface physico chemistry alters biofilm development of Pseudomonas aeruginosa lipopolysaccharide mutants

    NARCIS (Netherlands)

    Flemming, CA; Palmer, RJ; Arrage, AA; van der Mei, H.C.; White, DC

    1999-01-01

    The hydrophobic and electrostatic characteristics of bacterial cell surfaces were compared with attachment proclivity and biomass accumulation over time between wildtype Pseudomonas aeruginosa serotype O6 (possesses A and B band LPS), and three LPS-deficient mutants, vi;. A28 (A(+)B(-)), R5

  6. Reinforcement of the bactericidal effect of ciprofloxacin on Pseudomonas aeruginosa biofilm by hyperbaric oxygen treatment

    DEFF Research Database (Denmark)

    Kolpen, Mette; Mousavi, Nabi; Sams, Thomas

    2016-01-01

    Chronic Pseudomonas aeruginosa lung infection is the most severe complication in cystic fibrosis patients. It is characterised by antibiotic-tolerant biofilms in the endobronchial mucus with zones of oxygen (O2) depletion mainly due to polymorphonuclear leucocyte activity. Whilst the exact mechan...

  7. INTESTINAL BACTERIAL TRANSLOCATION IN EXPERIMENTALLY BURNED MICE WITH WOUNDS COLONIZED BY PSEUDOMONAS-AERUGINOSA

    NARCIS (Netherlands)

    MANSON, WL; COENEN, JMFH; KLASEN, HJ; HORWITZ, EH

    1992-01-01

    Translocation of micro-organisms from the gastrointestinal tract may play a role in the pathogenesis of septic complications in severely burned patients. We therefore investigated the influence of burn wound infection with Pseudomonas aeruginosa on translocation in experimentally burned mice. The P.

  8. Regulation of Amidase Formation in Mutants from Pseudomonas aeruginosa PAO Lacking Glutamine Synthetase Activity

    NARCIS (Netherlands)

    Janssen, Dick B.; Herst, Patricia M.; Joosten, Han M.L.J.; Drift, Chris van der

    1982-01-01

    The formation of amidase was studied in mutants from Pseudomonas aeruginosa PAO lacking glutamine synthetase activity. It appeared that catabolite repression of amidase synthesis by succinate was partially relieved when cellular growth was limited by glutamine. Under these conditions, a correlation

  9. Catabolite repression and nitrogen control of allantoin-degrading enzymes in Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Janssen, D.B.; Drift, C. van der

    1983-01-01

    The formation of the allantoin-degrading enzymes allantoinase, allantoicase and ureidoglycolase in Pseudomonas aeruginosa was found to be regulated by induction, catabolite repression and nitrogen control. Induction was observed when urate, allantoin or allantoate were included in the growth medium,

  10. Identification of quorum-sensing regulated proteins in the opportunistic pathogen Pseudomonas aeruginosa by proteomics

    DEFF Research Database (Denmark)

    Arevalo-Ferro, C.; Hentzer, Morten; Reil, G.

    2003-01-01

    The Gram-negative bacterium Pseudomonas aeruginosa is an opportunistic human pathogen which is responsible for severe nosocomial infections in immunocompromised patients and is the major pathogen in cystic fibrosis. The bacterium utilizes two interrelated quorum-sensing (QS) systems, which rely...

  11. Pseudo-outbreak of pseudomonas aeruginosa in HIV-infected patients undergoing fiberoptic bronchoscopy

    DEFF Research Database (Denmark)

    Kolmos, H J; Lerche, A; Kristoffersen, Kirsten Lydia

    1994-01-01

    Pseudomonas aeruginosa was isolated from bronchoalveolar lavage fluid from 8 consecutive patients undergoing bronchoscopy at an infectious diseases unit. None of the patients developed signs of respiratory tract infection that could be ascribed to the organism. The source of contamination was the...... indicate faulty disinfection of bronchoscopy equipment and thereby point to a risk of transmission of true respiratory pathogens such as mycobacteria....

  12. Pseudo-outbreak of pseudomonas aeruginosa in HIV-infected patients undergoing fiberoptic bronchoscopy

    DEFF Research Database (Denmark)

    Kolmos, H J; Lerche, A; Kristoffersen, Kirsten Lydia

    1994-01-01

    Pseudomonas aeruginosa was isolated from bronchoalveolar lavage fluid from 8 consecutive patients undergoing bronchoscopy at an infectious diseases unit. None of the patients developed signs of respiratory tract infection that could be ascribed to the organism. The source of contamination...... indicate faulty disinfection of bronchoscopy equipment and thereby point to a risk of transmission of true respiratory pathogens such as mycobacteria....

  13. Adhesion of Pseudomonas aeruginosa to contact lenses after exposure to multi-purpose lens care solutions

    NARCIS (Netherlands)

    Bruinsma, GM; Van der Mei, HC; Busscher, HJ; de Vries, Jacob

    2001-01-01

    Elemental surface compositions of contact lenses were measured after exposure to different lens care solutions (LCS) using X-ray photoelectron spectroscopy and were related to adhesion and detachment of Pseudomonas aeruginosa. Etafilcon A and polymacon contact lenses, prior to and after exposure to

  14. T helper cell subsets specific for Pseudomonas aeruginosa in healthy individuals and patients with cystic fibrosis.

    Directory of Open Access Journals (Sweden)

    Hannah K Bayes

    Full Text Available We set out to determine the magnitude of antigen-specific memory T helper cell responses to Pseudomonas aeruginosa in healthy humans and patients with cystic fibrosis.Peripheral blood human memory CD4(+ T cells were co-cultured with dendritic cells that had been infected with different strains of Pseudomonas aeruginosa. The T helper response was determined by measuring proliferation, immunoassay of cytokine output, and immunostaining of intracellular cytokines.Healthy individuals and patients with cystic fibrosis had robust antigen-specific memory CD4(+ T cell responses to Pseudomonas aeruginosa that not only contained a Th1 and Th17 component but also Th22 cells. In contrast to previous descriptions of human Th22 cells, these Pseudomonal-specific Th22 cells lacked the skin homing markers CCR4 or CCR10, although were CCR6(+. Healthy individuals and patients with cystic fibrosis had similar levels of Th22 cells, but the patient group had significantly fewer Th17 cells in peripheral blood.Th22 cells specific to Pseudomonas aeruginosa are induced in both healthy individuals and patients with cystic fibrosis. Along with Th17 cells, they may play an important role in the pulmonary response to this microbe in patients with cystic fibrosis and other conditions.

  15. Genomic Evolution Of The Mdr Serotype O12 Pseudomonas Aeruginosa Clone

    DEFF Research Database (Denmark)

    Thrane, Sandra Wingaard; Taylor, Véronique L.; Freschi, Luca

    2015-01-01

    Introduction: Since the 1980’s the serotype O12 of Pseudomonas aeruginosa has emerged as the predominant serotype in clinical settings and in epidemic outbreaks. These serotype O12 isolates exhibit high levels of resistance to various classes of antibiotics.Methods: In this study, we explore how ...

  16. Disulfide Bond-Containing Ajoene Analogues As Novel Quorum Sensing Inhibitors of Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Fong, July; Yuan, Mingjun; Jakobsen, Tim Holm

    2017-01-01

    Since its discovery 22 years ago, the bacterial cell-to-cell communication system, termed quorum sensing (QS), has shown potential as antipathogenic target. Previous studies reported that ajoene from garlic inhibits QS in opportunistic human pathogen Pseudomonas aeruginosa. In this study, screening...

  17. Thiourea-based spacers in potent divalent inhibitors of Pseudomonas aeruginosa virulence lectin LecA

    NARCIS (Netherlands)

    Pukin, Aliaksei V; Brouwer, Arwin J|info:eu-repo/dai/nl/304839191; Koomen, Leonie; Quarles van Ufford, H C|info:eu-repo/dai/nl/304839280; Kemmink, Johan|info:eu-repo/dai/nl/073230383; de Mol, Nico J|info:eu-repo/dai/nl/069011389; Pieters, Roland J|info:eu-repo/dai/nl/304827754

    2015-01-01

    A new divalent highly potent inhibitor of the Pseudomonas aeruginosa lectin and virulence factor LecA was prepared. It contains two thiourea linkages which were found to be in the Z,Z isomeric form. This brings the spacer into an elongated conformation required to bridge the two binding sites, which

  18. N-acylhomoserine-lactone-mediated communication between Pseudomonas aeruginosa and Burkholderia cepacia in mixed biofilms

    DEFF Research Database (Denmark)

    Riedel, K; Hentzer, Morten; Geisenberger, O

    2001-01-01

    Pseudomonas aeruginosa and Burkholderia cepacia are capable of forming mixed biofilms in the lungs of cystic fibrosis patients. Both bacteria employ quorum-sensing systems, which rely on N-acylhomoserine lactone (AHL) signal molecules, to co-ordinate expression of virulence factors with the forma...

  19. Permeabilization of biological and artificial membranes by a bacterial dirhamnolipid produced by Pseudomonas aeruginosa.

    Science.gov (United States)

    Sánchez, Marina; Aranda, Francisco J; Teruel, José A; Espuny, María J; Marqués, Ana; Manresa, Angeles; Ortiz, Antonio

    2010-01-15

    Pseudomonas aeruginosa, when cultured under the appropriate conditions, secretes rhamnolipids to the external medium. These glycolipids constitute one of the most interesting classes of biosurfactants so far. A dirhamnolipid fraction was isolated and purified from the crude biosurfactant, and its action on model and biological membranes was studied. Dirhamnolipid induced leakage of internal contents, as measured by the release of carboxyfluorescein, in phosphatidylcholine unilamellar vesicles, at concentrations below its CMC. Membrane solubilization was not observed within this concentration range. The presence of inverted cone-shaped lipids in the membrane, namely lysophosphatidylcholine, accelerated leakage, whereas cone-shaped lipids, like phosphatidylethanolamine, decreased leakage rate. Increasing concentrations of cholesterol protected the membrane against dirhamnolipid-induced leakage, which was totally abolished by the presence of 50 mol% of the sterol. Dirhamnolipid caused hemolysis of human erythrocytes through a lytic mechanism, as shown by the similar rates of K(+) and hemoglobin leakage, and by the absence of effect of osmotic protectants. Scanning electron microscopy showed that the addition of the biosurfactant changed the usual disc shape of erythrocytes into that of spheroechinocytes. The results are discussed within the frame of the biological actions of dirhamnolipid, and the possible future applications of this biosurfactant.

  20. The Extracellular Matrix Component Psl Provides Fast-Acting Antibiotic Defense in Pseudomonas aeruginosa Biofilms

    Science.gov (United States)

    Billings, Nicole; Ramirez Millan, Maria; Caldara, Marina; Rusconi, Roberto; Tarasova, Yekaterina; Stocker, Roman; Ribbeck, Katharina

    2013-01-01

    Bacteria within biofilms secrete and surround themselves with an extracellular matrix, which serves as a first line of defense against antibiotic attack. Polysaccharides constitute major elements of the biofilm matrix and are implied in surface adhesion and biofilm organization, but their contributions to the resistance properties of biofilms remain largely elusive. Using a combination of static and continuous-flow biofilm experiments we show that Psl, one major polysaccharide in the Pseudomonas aeruginosa biofilm matrix, provides a generic first line of defense toward antibiotics with diverse biochemical properties during the initial stages of biofilm development. Furthermore, we show with mixed-strain experiments that antibiotic-sensitive “non-producing” cells lacking Psl can gain tolerance by integrating into Psl-containing biofilms. However, non-producers dilute the protective capacity of the matrix and hence, excessive incorporation can result in the collapse of resistance of the entire community. Our data also reveal that Psl mediated protection is extendible to E. coli and S. aureus in co-culture biofilms. Together, our study shows that Psl represents a critical first bottleneck to the antibiotic attack of a biofilm community early in biofilm development. PMID:23950711

  1. Enhancing Growth of Vigna radiata in the Presence of Pseudomonas aeruginosa Biopolymer and Metarhizium anisopliae Spores

    Directory of Open Access Journals (Sweden)

    Bhagwan N. Rekadwad

    2016-01-01

    Full Text Available Exopolysaccharide producing Pseudomonas aeruginosa NCIM 2945 (PANCL belonging to gamma-proteobacterium and entomopathogenic fungus Metarhizium anisopliae MCC 1129 (MAMCC belonging to Ascomycota were studied for their morphological features biochemical characteristics and plant growth promotion ability. Optimum growth of PANCL was recorded after 24 h at temperature 30°C and pH 7.0. Gram-negative PANCL appeared as white in color, one mm size, circular, opaque, and nonconsistent elevated colonies with entire margin. It has utilized dextrose, fructose, maltose, and sorbitol as carbon source and produced acid in the medium. PANCL was sensitive to Polymyxin B (300 µgm/disc followed by Neomycin (30 µgm/disc, Gentamycin (10 µgm/disc, and Chloramphenicol (30 µgm/disc. PANCL has secreted extracellular lipase, amylase, protease, and exopolysaccharides (EPS. Another fungal strain MAMCC sporulated after 168 h at temperature 30°C and pH 7.0. MAMCC has septate-white mycelium and bears dirty green colored spores. Growth of MAMCC was enhanced in the presence of Neem and Karela-Amla oil (0.1 mL each. Extracellular polysaccharide produced by PANCL and spores of MAMCC promoted growth of dicotyledon Vigna radiata (Mung individually as well as in consortium. Considerable increase in dry weight of Vigna radiata was recorded. Thus, reported PANCL and MAMCC strains have promoted growth Vigna radiata and may be a solution for sustainable agriculture.

  2. Systematic investigations on the biodegradation and viscosity reduction of long chain hydrocarbons using Pseudomonas aeruginosa and Pseudomonas fluorescens.

    Science.gov (United States)

    Sakthipriya, N; Doble, Mukesh; Sangwai, Jitendra S

    2016-03-01

    The use of microorganisms has been researched extensively for possible applications related to hydrocarbon degradation in the petroleum industry. However, attempts to improve the effect of microorganisms on the viscosity of hydrocarbons, which find potential use in the development of robust models for biodegradation, have been rarely documented. This study investigates the degradation of long chain hydrocarbons, such as hexadecane and eicosane using Pseudomonas fluorescens PMMD3 (P. fluorescens) and Pseudomonas aeruginosa CPCL (P. aeruginosa). P. aeruginosa used here is isolated from petroleum contaminated sediments and the P. fluorescens is from the coastal area, and both have hydrocarbon degrading genes. The degradation of hydrocarbons is studied using carbon profiling and reduction in viscosity pre- and post-degradation of hydrocarbons. The carbon profiling has been obtained using gas chromatography-mass spectroscopy (GC-MS), and Fourier transform infrared spectrometer (FTIR) results. GC-MS results have indicated an improved biodegradation of hydrocarbons by 77-93% in one day. The yield coefficients of biomass (YX/S) for P. aeruginosa and P. fluorescens using hexadecane as a carbon source are 1.35 and 0.81 g g(-1), and the corresponding values with eicosane are 0.84 and 0.88 g g(-1). The viscosity of hexadecane is reduced by the order of 53 and 47%, while that of eicosane was reduced by 53 and 65%, using P. aeruginosa and P. fluorescens, respectively. This study also presents information on the activity of enzymes responsible for the hydrocarbon degradation. Pseudomonas species have shown their use in potential applications for bioremediation, oil-spill treatment, and flow assurance. We believe that this study will also provide stringent tests for possible model development for the bioremediation of long chain paraffins suitable for oilfield applications.

  3. Surfactants and the attachment of Pseudomonas aeruginosa to ...

    African Journals Online (AJOL)

    2-phenylidole (DAPI) staining, scanning electron microscopy (SEM) and spectrophotometry for their efficacy in preventing adhesion and removing Ps. Aeruginosa attached to 3CR12 stainless steel coupons and glass. All the surfactants tested ...

  4. Pseudomonas aeruginosa diversity in distinct paediatric patient groups

    DEFF Research Database (Denmark)

    Tramper-Stranders, G.A.; Ent, C.K. van der; Wolfs, T.F.

    2008-01-01

    -CF patients and whether clonality of isolates occurs in other patient groups. The aim of this study was to investigate P. aeruginosa diversity and the occurrence of clones within five distinct paediatric patient groups susceptible to P. aeruginosa infection. P. aeruginosa isolates were cultured from 157...... patients (CF first infection (CF-1 group) (29); CF chronic infection (CF-chronic group) (27); urinary tract infection (34); chronic suppurative otitis media (43); and intensive-care hospitalization/immunodeficiency (24)). All 202 phenotypically different isolates were tested for antimicrobial resistance...... and further typed by pulsed-field gel electrophoresis. Simpson's diversity index was calculated for the five groups. CF-chronic patients carried the highest number of distinct P. aeruginosa phenotypes and genotypes per culture. Isolates from the CF-chronic group were significantly less diverse than those from...

  5. Prevalence of Pseudomonas aeruginosa and antimicrobial-resistant Pseudomonas aeruginosa in patients with pneumonia in mainland China: a systematic review and meta-analysis.

    Science.gov (United States)

    Ding, Chengyi; Yang, Zhirong; Wang, Jing; Liu, Xinran; Cao, Yu; Pan, Yuting; Han, Lizhong; Zhan, Siyan

    2016-08-01

    To estimate the prevalence of Pseudomonas aeruginosa and antimicrobial-resistant P. aeruginosa in ventilator-associated pneumonia (VAP), hospital-acquired pneumonia (HAP), and community-acquired pneumonia (CAP) in mainland China. Meta-analyses of 50 studies published from 2010 to 2014 were conducted, followed by pre-defined subgroup analyses and meta-regressions. P. aeruginosa accounted for 19.4% (95% confidence interval (CI) 17.6-21.2%) of all isolates in VAP, which was similar to the proportion in HAP of 17.8% (95% CI 14.6-21.6%), but significantly greater than the proportion in CAP of 7.7% (15/195, presistance to agents recommended for the initial management of VAP, with a high level of resistance to gentamicin (51.1%, 95% CI 37.7-64.4%) and a low level of resistance to amikacin (22.5%, 95% CI 14.3-33.6%). The prevalence of P. aeruginosa isolates resistant to agents recommended for the treatment of HAP ranged from 22.2% (95% CI 13.8-33.6%) for amikacin to 50.0% (95% CI 30.2-69.8%) for cefoperazone. P. aeruginosa was highly prevalent among patients with VAP and HAP in mainland China. The initial empirical treatment of these patients remains challenging because of the strikingly high prevalence of antimicrobial resistance. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  6. Pseudomonas aeruginosa Alters Staphylococcus aureus Sensitivity to Vancomycin in a Biofilm Model of Cystic Fibrosis Infection

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    Giulia Orazi

    2017-07-01

    Full Text Available The airways of cystic fibrosis (CF patients have thick mucus, which fosters chronic, polymicrobial infections. Pseudomonas aeruginosa and Staphylococcus aureus are two of the most prevalent respiratory pathogens in CF patients. In this study, we tested whether P. aeruginosa influences the susceptibility of S. aureus to frontline antibiotics used to treat CF lung infections. Using our in vitro coculture model, we observed that addition of P. aeruginosa supernatants to S. aureus biofilms grown either on epithelial cells or on plastic significantly decreased the susceptibility of S. aureus to vancomycin. Mutant analyses showed that 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO, a component of the P. aeruginosa Pseudomonas quinolone signal (PQS system, protects S. aureus from the antimicrobial activity of vancomycin. Similarly, the siderophores pyoverdine and pyochelin also contribute to the ability of P. aeruginosa to protect S. aureus from vancomycin, as did growth under anoxia. Under our experimental conditions, HQNO, P. aeruginosa supernatant, and growth under anoxia decreased S. aureus growth, likely explaining why this cell wall-targeting antibiotic is less effective. P. aeruginosa supernatant did not confer additional protection to slow-growing S. aureus small colony variants. Importantly, P. aeruginosa supernatant protects S. aureus from other inhibitors of cell wall synthesis as well as protein synthesis-targeting antibiotics in an HQNO- and siderophore-dependent manner. We propose a model whereby P. aeruginosa causes S. aureus to shift to fermentative growth when these organisms are grown in coculture, leading to reduction in S. aureus growth and decreased susceptibility to antibiotics targeting cell wall and protein synthesis.

  7. Gallium-Protoporphyrin IX Inhibits Pseudomonas aeruginosa Growth by Targeting Cytochromes.

    Science.gov (United States)

    Hijazi, Sarah; Visca, Paolo; Frangipani, Emanuela

    2017-01-01

    Pseudomonas aeruginosa is a challenging pathogen due to both innate and acquired resistance to antibiotics. It is capable of causing a variety of infections, including chronic lung infection in cystic fibrosis (CF) patients. Given the importance of iron in bacterial physiology and pathogenicity, iron-uptake and metabolism have become attractive targets for the development of new antibacterial compounds. P. aeruginosa can acquire iron from a variety of sources to fulfill its nutritional requirements both in the environment and in the infected host. The adaptation of P. aeruginosa to heme iron acquisition in the CF lung makes heme utilization pathways a promising target for the development of new anti-Pseudomonas drugs. Gallium [Ga(III)] is an iron mimetic metal which inhibits P. aeruginosa growth by interfering with iron-dependent metabolism. The Ga(III) complex of the heme precursor protoporphyrin IX (GaPPIX) showed enhanced antibacterial activity against several bacterial species, although no inhibitory effect has been reported on P. aeruginosa. Here, we demonstrate that GaPPIX is indeed capable of inhibiting the growth of clinical P. aeruginosa strains under iron-deplete conditions, as those encountered by bacteria during infection, and that GaPPIX inhibition is reversed by iron. Using P. aeruginosa PAO1 as model organism, we show that GaPPIX enters cells through both the heme-uptake systems has and phu, primarily via the PhuR receptor which plays a crucial role in P. aeruginosa adaptation to the CF lung. We also demonstrate that intracellular GaPPIX inhibits the aerobic growth of P. aeruginosa by targeting cytochromes, thus interfering with cellular respiration.

  8. Evaluation of a FRET-peptide substrate to predict virulence in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Wendy E Kaman

    Full Text Available Pseudomonas aeruginosa produces a number of proteases that are associated with virulence and disease progression. A substrate able to detect P. aeruginosa-specific proteolytic activity could help to rapidly alert clinicians to the virulence potential of individual P. aeruginosa strains. For this purpose we designed a set of P. aeruginosa-specific fluorogenic substrates, comprising fluorescence resonance energy transfer (FRET-labeled peptides, and evaluated their applicability to P. aeruginosa virulence in a range of clinical isolates. A FRET-peptide comprising three glycines (3xGly was found to be specific for the detection of P. aeruginosa proteases. Further screening of 97 P. aeruginosa clinical isolates showed a wide variation in 3xGly cleavage activity. The absence of 3xGly degradation by a lasI knock out strain indicated that 3xGly cleavage by P. aeruginosa could be quorum sensing (QS-related, a hypothesis strengthened by the observation of a strong correlation between 3xGly cleavage, LasA staphylolytic activity and pyocyanin production. Additionally, isolates able to cleave 3xGly were more susceptible to the QS inhibiting antibiotic azithromycin (AZM. In conclusion, we designed and evaluated a 3xGly substrate possibly useful as a simple tool to predict virulence and AZM susceptibility.

  9. Genetic Characterization Indicates that a Specific Subpopulation of Pseudomonas aeruginosa Is Associated with Keratitis Infections▿

    Science.gov (United States)

    Stewart, Rosalind M. K.; Wiehlmann, Lutz; Ashelford, Kevin E.; Preston, Stephanie J.; Frimmersdorf, Eliane; Campbell, Barry J.; Neal, Timothy J.; Hall, Neil; Tuft, Stephen; Kaye, Stephen B.; Winstanley, Craig

    2011-01-01

    Pseudomonas aeruginosa is a common opportunistic bacterial pathogen that causes a variety of infections in humans. Populations of P. aeruginosa are dominated by common clones that can be isolated from diverse clinical and environmental sources. To determine whether specific clones are associated with corneal infection, we used a portable genotyping microarray system to analyze a set of 63 P. aeruginosa isolates from patients with corneal ulcers (keratitis). We then used population analysis to compare the keratitis isolates to a wider collection of P. aeruginosa from various nonocular sources. We identified various markers in a subpopulation of P. aeruginosa associated with keratitis that were in strong disequilibrium with the wider P. aeruginosa population, including oriC, exoU, katN, unmodified flagellin, and the carriage of common genomic islands. The genome sequencing of a keratitis isolate (39016; representing the dominant serotype O11), which was associated with a prolonged clinical healing time, revealed several genomic islands and prophages within the accessory genome. The PCR amplification screening of all 63 keratitis isolates, however, provided little evidence for the shared carriage of specific prophages or genomic islands between serotypes. P. aeruginosa twitching motility, due to type IV pili, is implicated in corneal virulence. We demonstrated that 46% of the O11 keratitis isolates, including 39016, carry a distinctive pilA, encoding the pilin of type IV pili. Thus, the keratitis isolates were associated with specific characteristics, indicating that a subpopulation of P. aeruginosa is adapted to cause corneal infection. PMID:21227987

  10. A commensal streptococcus hijacks a Pseudomonas aeruginosa exopolysaccharide to promote biofilm formation.

    Directory of Open Access Journals (Sweden)

    Jessica A Scoffield

    2017-04-01

    Full Text Available Pseudomonas aeruginosa causes devastating chronic pulmonary infections in cystic fibrosis (CF patients. Although the CF airway is inhabited by diverse species of microorganisms interlaced within a biofilm, many studies focus on the sole contribution of P. aeruginosa pathogenesis in CF morbidity. More recently, oral commensal streptococci have been identified as cohabitants of the CF lung, but few studies have explored the role these bacteria play within the CF biofilm. We examined the interaction between P. aeruginosa and oral commensal streptococci within a dual species biofilm. Here we report that the CF P. aeruginosa isolate, FRD1, enhances biofilm formation and colonization of Drosophila melanogaster by the oral commensal Streptococcus parasanguinis. Moreover, production of the P. aeruginosa exopolysaccharide, alginate, is required for the promotion of S. parasanguinis biofilm formation and colonization. However, P. aeruginosa is not promoted in the dual species biofilm. Furthermore, we show that the streptococcal adhesin, BapA1, mediates alginate-dependent enhancement of the S. parasanguinis biofilm in vitro, and BapA1 along with another adhesin, Fap1, are required for the in vivo colonization of S. parasanguinis in the presence of FRD1. Taken together, our study highlights a new association between streptococcal adhesins and P. aeruginosa alginate, and reveals a mechanism by which S. parasanguinis potentially colonizes the CF lung and interferes with the pathogenesis of P. aeruginosa.

  11. Autoinducer-2 Facilitates Pseudomonas aeruginosa PAO1 Pathogenicity in Vitro and in Vivo

    Directory of Open Access Journals (Sweden)

    Hongdong Li

    2017-10-01

    Full Text Available Bacterial communication systems, such as quorum sensing (QS, have provided new insights of alternative approaches in antimicrobial treatment. We recently reported that one QS signal, named as autoinducer-2 (AI-2, can affect the behaviors of Pseudomonas aeruginosa PAO1 in a dose-dependent manner. In this study, we aimed to investigate the effects of AI-2 on P. aeruginosa PAO1 biofilm formation and virulence factors production in vitro, and in vivo using a pulmonary infection mouse model. Exogenous AI-2 resulted in increased biofilms architecture, the number of viable cells, and the yield of pyocyanin and elastase virulence factors in wild type P. aeruginosa PAO1. However, no such effect was observed in P. aeruginosa lasR rhlR mutant strain. In vivo, the use of AI-2 significantly increased the mortality, lung bacterial count and histological lung damage of mice with acute P. aeruginosa PAO1 infection. Our data suggest that AI-2 promotes the formation of P. aeruginosa PAO1 biofilms and the production of virulence factors by interfering with P. aeruginosa QS systems, resulting in decreased host survival. AI-2 may be a therapeutic target for the clinical treatment of a co-infection of P. aeruginosa and AI-2 producing bacteria.

  12. Clinical and Morphological Studies on Spontaneous Cases of Pseudomonas aeruginosa Infections in Birds

    Directory of Open Access Journals (Sweden)

    I Dinev1, S Denev2* and G Beev2

    2013-07-01

    Full Text Available Clinical, pathoanatomical, histological, and bacteriological studies were performed on broiler chickens, growing broiler parents, and growing egg layers, in three different poultry farms, after an outbreak of Pseudomonas aeruginosa infections. The method of contamination of the birds was established. Several local and systemic clinico-morphological forms of spontaneous P. aeruginosa infections in various categories of stock birds were described: cases of P. aeruginosa infection resulting from injection of contaminated vaccines; case of P. aeruginosa infections through contaminated aerosol vaccine and cases of pododermatitis, periarthritis and arthritis in broiler chickens associated with P. aeruginosa infection. In different cases mortality range between 0.5 and 50%. The results showed that apart from embryonic mortality in hatcheries, and septicemic infections in newly hatched chickens, the pathogenicity of P. aeruginosa was associated with localized and systemic lesions in this category, as well as in young and growing birds. On one hand, these results have a theoretical significance, contributing for the confirmation and expansion of the wide array of clinico-morphological forms of P. aeruginosa infections in birds. On the other hand, the knowledge on these forms has a purely practical significance in the diagnostics of P. aeruginosa infections by poultry pathologists and veterinary practitioners.

  13. Detection of Pseudomonas aeruginosa in sputum headspace through volatile organic compound analysis

    Directory of Open Access Journals (Sweden)

    Goeminne Pieter C

    2012-10-01

    Full Text Available Abstract Introduction Chronic pulmonary infection is the hallmark of Cystic Fibrosis lung disease. Searching for faster and easier screening may lead to faster diagnosis and treatment of Pseudomonas aeruginosa (P. aeruginosa. Our aim was to analyze and build a model to predict the presence of P. aeruginosa in sputa. Methods Sputa from 28 bronchiectatic patients were used for bacterial culturing and analysis of volatile compounds by gas chromatography–mass spectrometry. Data analysis and model building were done by Partial Least Squares Regression Discriminant analysis (PLS-DA. Two analysis were performed: one comparing P. aeruginosa positive with negative cultures at study visit (PA model and one comparing chronic colonization according to the Leeds criteria with P. aeruginosa negative patients (PACC model. Results The PA model prediction of P. aeruginosa presence was rather poor, with a high number of false positives and false negatives. On the other hand, the PACC model was stable and explained chronic P. aeruginosa presence for 95% with 4 PLS-DA factors, with a sensitivity of 100%, a positive predictive value of 86% and a negative predictive value of 100%. Conclusion Our study shows the potential for building a prediction model for the presence of chronic P. aeruginosa based on volatiles from sputum.

  14. Predicting the growth situation of Pseudomonas aeruginosa on agar plates and meat stuffs using gas sensors

    Science.gov (United States)

    Gu, Xinzhe; Sun, Ye; Tu, Kang; Dong, Qingli; Pan, Leiqing

    2016-12-01

    A rapid method of predicting the growing situation of Pseudomonas aeruginosa is presented. Gas sensors were used to acquire volatile compounds generated by P. aeruginosa on agar plates and meat stuffs. Then, optimal sensors were selected to simulate P. aeruginosa growth using modified Logistic and Gompertz equations by odor changes. The results showed that the responses of S8 or S10 yielded high coefficients of determination (R2) of 0.89-0.99 and low root mean square errors (RMSE) of 0.06-0.17 for P. aeruginosa growth, fitting the models on the agar plate. The responses of S9, S4 and the first principal component of 10 sensors fit well with the growth of P. aeruginosa inoculated in meat stored at 4 °C and 20 °C, with R2 of 0.73-0.96 and RMSE of 0.25-1.38. The correlation coefficients between the fitting models, as measured by electronic nose responses, and the colony counts of P. aeruginosa were high, ranging from 0.882 to 0.996 for both plate and meat samples. Also, gas chromatography-mass spectrometry results indicated the presence of specific volatiles of P. aeruginosa on agar plates. This work demonstrated an acceptable feasibility of using gas sensors—a rapid, easy and nondestructive method for predicting P. aeruginosa growth.

  15. A commensal streptococcus hijacks a Pseudomonas aeruginosa exopolysaccharide to promote biofilm formation.

    Science.gov (United States)

    Scoffield, Jessica A; Duan, Dingyu; Zhu, Fan; Wu, Hui

    2017-04-01

    Pseudomonas aeruginosa causes devastating chronic pulmonary infections in cystic fibrosis (CF) patients. Although the CF airway is inhabited by diverse species of microorganisms interlaced within a biofilm, many studies focus on the sole contribution of P. aeruginosa pathogenesis in CF morbidity. More recently, oral commensal streptococci have been identified as cohabitants of the CF lung, but few studies have explored the role these bacteria play within the CF biofilm. We examined the interaction between P. aeruginosa and oral commensal streptococci within a dual species biofilm. Here we report that the CF P. aeruginosa isolate, FRD1, enhances biofilm formation and colonization of Drosophila melanogaster by the oral commensal Streptococcus parasanguinis. Moreover, production of the P. aeruginosa exopolysaccharide, alginate, is required for the promotion of S. parasanguinis biofilm formation and colonization. However, P. aeruginosa is not promoted in the dual species biofilm. Furthermore, we show that the streptococcal adhesin, BapA1, mediates alginate-dependent enhancement of the S. parasanguinis biofilm in vitro, and BapA1 along with another adhesin, Fap1, are required for the in vivo colonization of S. parasanguinis in the presence of FRD1. Taken together, our study highlights a new association between streptococcal adhesins and P. aeruginosa alginate, and reveals a mechanism by which S. parasanguinis potentially colonizes the CF lung and interferes with the pathogenesis of P. aeruginosa.

  16. Virulence Genes Profile of Multidrug Resistant Pseudomonas aeruginosa Isolated from Iranian Children with UTIs

    Directory of Open Access Journals (Sweden)

    Zohreh Heidary

    2016-04-01

    Full Text Available Virulent and resistant strains Pseudomonas aeruginosa (P. aeruginosa is one of the most important cause of UTIs in pediatrics. The present study was carried to investigate the frequency of virulence factors in the multi-drug resistant strains of P. aeruginosa isolated from pediatrics hospitalized due to the UTIs. One - hundred and forty three urine samples were collected from pediatric patients suffered from UTIs. Samples were cultured and those that were P. aeruginosa positive were analyzed for the presence of putative virulence genes. Seventy one out of 143 samples (49.65% were positive for P. aeruginosa. Monthly, sex and age-dependent prevalence were seen for P. aeruginosa. Bacterial strains had the highest levels of resistance against ampicillin (95.77%, gentamicin (92.95% and ciprofloxacin (81.69%. Of 71 P. aeruginosa isolates, 12 strains were resistant to more than 9 antibiotics (16.90%. The most commonly detected virulence factors in the cases of urethral infections were exoU and plcH while those of pyelonephritis and cystitis were were exoS and lasB. Our findings should raise awareness about antibiotic resistance in hospitalized pediatrics with UTIs in Iran. Clinicians should exercise caution in prescribing antibiotics, especially in cases of UTIs. Such information can help in identifying these virulence genes as useful diagnostic markers for clinical P. aeruginosa strains isolated from UTIs.

  17. Antimicrobial Susceptibility Patterns of Pseudomonas aeruginosa from Diabetes Patients with Foot Ulcers

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    Tamil Selvi Sivanmaliappan

    2011-01-01

    Full Text Available Pseudomonas aeruginosa is an invasive organism that frequently causes severe tissue damage in diabetic foot ulcers. A major problem in P. aeruginosa infection may be that this pathogen exhibits a high degree of resistance to a broad spectrum of antibiotics. The study aimed to isolate and determine the antimicrobial susceptibility patterns of the P. aeruginosa population from diabetes patients with foot ulcers attending tertiary care hospitals in and around Coimbatore and their antimicrobial susceptibility pattern. The study was carried out at the Department of Microbiology, Dr. N.G.P. Arts and Science College, Coimbatore, for a period of one year (June 2006 to April 2007. The present study comprised 270 pus specimens collected from diabetic patients with foot ulcers. All pus samples were subjected to gram staining; bacterial culture and subsequently the antibiotic sensitivity to 15 different antibiotics for the confirmed P. aeruginosa were performed as per the standard procedures. Eighteen strains (14.28% of P. aeruginosa from 270 diabetic foot ulcers were detected. Almost all the strains exhibited a varying degree of resistance to the antibiotics tested. Multidrug resistance for about 8 to 11 antibiotics was observed among the 55.5% of the isolates. Disk diffusion results show 100% resistance to ampicillin, cefoperazone, erythromycin, norfloxacin, and only cefotaxime, ciprofloxacin exhibited greater activity against Pseudomonas aeruginosa.

  18. ANTIMICROBIAL ACTIVITY OF PINEAPPLE (ANANAS COMOSUS L. MERR EXTRACT AGAINST MULTIDRUG-RESISTANT OF PSEUDOMONAS AERUGINOSA: AN IN VITRO STUDY

    Directory of Open Access Journals (Sweden)

    Rahmat Sayyid Zharfan

    2017-08-01

    Full Text Available Pseudomonas aeruginosa is the main cause of nosocomial infection which is responsible for 10% of hospital-acquired infection. Pseudomonas aeruginosa tends to mutate and displays potential for development of antibiotic resistance. Approximately, 10% of global bacterial isolates are found as Multidrug-resistant Pseudomonas aeruginosa. Pseudomonas aeruginosa have a quite tremendous severity index, especially on pneumonia and urinary tract infections, even sepsis, which 50% mortality rate. Pineapple (Ananas comosus L. Merr has antimicrobial properties. The active antimicrobial compounds in Ananas comosus L. Merr include saponin and bromelain. This research aims to find the potency of antimicrobial effect of pineapple (Ananas comosus L. Merr extract towards Multidrug-resistant Pseudomonas aeruginosa. Multidrug-resistant Pseudomonas aeruginosa specimen is obtained from patient’s pus in orthopaedic department, Dr Soetomo Public Hospital, Surabaya. Multidrug-resistant Pseudomonas aeruginosa specimen is resistant to all antibiotic agents except cefoperazone-sulbactam. This research is conducted by measuring the Minimum Inhibitory Concentration (MIC through dilution test with Mueller-Hinton broth medium. Pineapple extract (Ananas comosus L. Merr. is dissolved in aquadest, then poured into test tube at varying concentrations (6 g/ml; 3 g/ml; 1.5 g/ml; 0.75 g/ml, 0.375 g/ml; and 0.1875 g/ml. After 24 hours’ incubation, samples are plated onto nutrient agar plate, to determine the Minimum Bactericidal Concentration (MBC. The extract of pineapple (Ananas comosus L. Merr has antimicrobial activities against Multidrug-resistant Pseudomonas aeruginosa. Minimum Inhibitory Concentration (MIC could not be determined, because turbidity changes were not seen. The Minimum Bactericidal Concentration (MBC of pineapple extract (Ananas comosus L. Merr to Multidrug-resistant Pseudomonas aeruginosa is 0.75 g/ml. Further study of in vivo is needed.

  19. Secretome of transmissible Pseudomonas aeruginosa AES-1R grown in a cystic fibrosis lung-like environment.

    Science.gov (United States)

    Scott, Nichollas E; Hare, Nathan J; White, Melanie Y; Manos, Jim; Cordwell, Stuart J

    2013-12-06

    Pseudomonas aeruginosa is the predominant cause of mortality in patients with cystic fibrosis (CF). We examined the secretome of an acute, transmissible CF P. aeruginosa (Australian epidemic strain 1-R; AES-1R) compared with laboratory-adapted PAO1. Culture supernatant proteins from rich (LB) and minimal (M9) media were compared using 2-DE and 2DLC-MS/MS, which revealed elevated abundance of PasP protease and absence of AprA protease in AES-1R. CF lung-like artificial sputum medium (ASMDM) contains serum and mucin that generally preclude proteomics of secreted proteins. ASMDM culture supernatants were subjected to 2DLC-MS/MS, which allowed the identification of 57 P. aeruginosa proteins, and qualitative spectral counting was used to estimate relative abundance. AES-1R-specific AES_7139 and PasP were more abundant in AES-1R ASMDM culture supernatants, while AprA could only be identified in PAO1. Relative quantitation was performed using selected reaction monitoring. Significantly elevated levels of PasP, LasB, chitin-binding protein (CbpD), and PA4495 were identified in AES-1R ASMDM supernatants. Quantitative PCR showed elevated pasP in AES-1R during early (18 h) ASMDM growth, while no evidence of aprA expression could be observed. Genomic screening of CF isolates revealed aes_7139 was present in all AES-1 and one pair of sequential nonepidemic isolates. Secreted proteins may be crucial in aiding CF-associated P. aeruginosa to establish infection and for adaptation to the CF lung.

  20. Inhibitory and stimulatory effects of Pseudomonas aeruginosa pyocyanine on human T and B lymphocytes and human monocytes.

    Science.gov (United States)

    Ulmer, A J; Pryjma, J; Tarnok, Z; Ernst, M; Flad, H D

    1990-01-01

    Pyocyanine, a pigment produced by Pseudomonas aeruginosa, has dual dose-dependent stimulatory as well as inhibitory effects on immune responses in vitro as measured by DNA synthesis of human T and B lymphocytes, interleukin-2 (IL-2) production by human T lymphocytes, immunoglobulin production by human B lymphocytes, and monokine production by human monocytes. In general, stimulatory activity was found at low concentrations of pyocyanine, whereas high concentrations of the pigment resulted in an inhibition of responses. At a pyocyanine concentration of 0.1 micrograms/ml or less the proliferation of T and B lymphocytes was enhanced, but at 0.5 micrograms/ml it was suppressed. IL-2 production by T lymphocytes was enhanced at concentrations up to 0.5 micrograms/ml but totally inhibited at 1.0 micrograms/ml. The differentiation of B lymphocytes to become immunoglobulin-producing cells was also enhanced in the presence of low doses of pyocyanine, whereas secretion of immunoglobulin by B lymphocytes was suppressed at all concentrations of pyocyanine. In contrast to the dual effects of pyocyanine on lymphocyte response, lipopolysaccharide-induced IL-1 and tumor necrosis factor release by monocytes was markedly enhanced by low as well as high concentrations of pyocyanine. From these results we conclude that this property of pyocyanine may lead to suppression of specific defense mechanisms and enhance harmful inflammatory reactions of the host during infection with Pseudomonas aeruginosa. PMID:2106495