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Sample records for aeruginosa azurin-gold nanoparticle

  1. Long-Range Interfacial Electrochemical Electron Transfer of Pseudomonas aeruginosa Azurin-Gold Nanoparticle Hybrid Systems

    DEFF Research Database (Denmark)

    Jensen, Palle Skovhus; Chi, Qijin; Zhang, Jingdong;

    2009-01-01

    We have prepared a "hybrid" of the blue copper protein azurin (Pseudomonas aeruginosa) and a 3 nm gold nanoparticle (AuNP). The AuNP/azurin hybrid was assembled on a Au(111)-electrode surface in a two-step process. The AuNP was first attached to the Au(111) electrode via Au-S chemisorption of a 4...

  2. Comparison of antibacterial activities of cadmium oxide nanoparticles against Pseudomonas Aeruginosa and Staphylococcus Aureus bacteria

    Directory of Open Access Journals (Sweden)

    Bahareh Salehi

    2015-01-01

    Conclusion: This study showed that antibacterial effects of cadmium oxide nanoparticles on positive gram bacteria are stronger than negative gram bacteria and antibacterial effects of cdo nanoparticles against both bacteria, but Staphylococcus aureus bacteria were more sensitive to nanoparticles as compared to Pseudomonas aeruginosa.

  3. Nitrosoglutathione generating nitric oxide nanoparticles as an improved strategy for combating Pseudomonas aeruginosa-infected wounds.

    Science.gov (United States)

    Chouake, Jason; Schairer, David; Kutner, Allison; Sanchez, David A; Makdisi, Joy; Blecher-Paz, Karin; Nacharaju, Parimala; Tuckman-Vernon, Chaim; Gialanella, Phil; Friedman, Joel M; Nosanchuk, Joshua D; Friedman, Adam J

    2012-12-01

    Pseudomonas aeruginosa is a community-acquired, nosocomial pathogen that is an important cause of human morbidity and mortality; it is intrinsically resistant to several antibiotics and is capable of developing resistance to newly developed drugs via a variety of mechanisms. P aeruginosa's ubiquity and multidrug resistance (MDR) warrants the development of innovative methods that overcome its ability to develop resistance. We have previously described a nitric oxide-releasing nanoparticle (NO-np) platform that effectively kills gram-positive and gram-negative organisms in vitro and accelerates clinical recovery in vivo in murine wound and abscess infection models. We have also demonstrated that when glutathione (GSH) is added to NO-np, the nitroso intermediate S-nitrosoglutathione (GSNO) is formed, which has greater activity against P aeruginosa and other gram-negative organisms compared with NO-np alone. In the current study, we evaluate the potential of NO-np to generate GSNO both in vitro and in vivo in a murine excisional wound model infected with an MDR clinical isolate of P aeruginosa. Whereas NO-np alone inhibited P aeruginosa growth in vitro for up to 8 hours, NO-np+GSH completely inhibited P aeruginosa growth for 24 hours. Percent survival in the NO-np+GSH-treated isolates was significantly lower than in the NO-np (36.1% vs 8.3%; P=.004). In addition, NO-np+GSH accelerated wound closure in P aeruginosa-infected wounds, and NO-np+GSH-treated wounds had significantly lower bacterial burden when compared to NO-np-treated wounds (P<.001). We conclude that GSNO is easily generated from our NO-np platform and has the potential to be used as an antimicrobial agent against MDR organisms such as P aeruginosa. PMID:23377518

  4. Inhibited growth of Pseudomonas aeruginosa by dextran- and polyacrylic acid-coated ceria nanoparticles

    Directory of Open Access Journals (Sweden)

    Wang Q

    2013-08-01

    Full Text Available Qi Wang,1 J Manuel Perez,2 Thomas J Webster1,3 1Bioengineering Program, College of Engineering, Northeastern University, Boston, MA, USA; 2Nanoscience Technology Center, University of Central Florida, Orlando, FL, USA; 3Department of Chemical Engineering, College of Engineering, Northeastern University, Boston, MA, USA Abstract: Ceria (CeO2 nanoparticles have been widely studied for numerous applications, but only a few recent studies have investigated their potential applications in medicine. Moreover, there have been almost no studies focusing on their possible antibacterial properties, despite the fact that such nanoparticles may reduce reactive oxygen species. In this study, we coated CeO2 nanoparticles with dextran or polyacrylic acid (PAA because of their enhanced biocompatibility properties, minimized toxicity, and reduced clearance by the immune system. For the first time, the coated CeO2 nanoparticles were tested in bacterial assays involving Pseudomonas aeruginosa, one of the most significant bacteria responsible for infecting numerous medical devices. The results showed that CeO2 nanoparticles with either coating significantly inhibited the growth of Pseudomonas aeruginosa, by up to 55.14%, after 24 hours compared with controls (no particles. The inhibition of bacterial growth was concentration dependent. In summary, this study revealed, for the first time, that the characterized dextran- and PAA-coated CeO2 nanoparticles could be potential novel materials for numerous antibacterial applications. Keywords: antibacterial, biomedical applications

  5. Comparison of antibacterial activities of cadmium oxide nanoparticles against Pseudomonas Aeruginosa and Staphylococcus Aureus bacteria

    OpenAIRE

    Bahareh Salehi; Esmaeil Mortaz; Payam Tabarsi

    2015-01-01

    Background: Inorganic antibacterial factors have bacterial resistance and high thermal stability. Inorganic nanomaterials which have new structures with biological, chemical and physical properties have been made since their applications due to their nano size. In this study, the antibacterial effect of cadmium oxide nanoparticles on Staphylococcus aureus and Pseudomonas aeruginosa bacteria was investigated. Materials and Methods: The different concentrations (10 μg/ml, 15 μg/ml and 20 μg...

  6. Inhibitory effect of zinc oxide nanoparticles on pseudomonas aeruginosa biofilm formation

    OpenAIRE

    Mohammad Hassani Sangani; Mahboobeh Nakhaei Moghaddam; Mohammad Mahdi Forghanifard

    2015-01-01

    Objective(s): Bacterial biofilm formation causes many persistent and chronic infections. The matrix protects biofilm bacteria from exposure to innate immune defenses and antibiotic treatments. The purpose of this study was to evaluate the biofilm formation of clinical isolates of Pseudomonas aeruginosa and the activity of zinc oxide nanoparticles (ZnO NPs) on biofilm. Materials and Methods: After collecting bacteria from clinical samples of hospitalized patients, the ability of organisms were...

  7. Inhibitory effect of zinc oxide nanoparticles on pseudomonas aeruginosa biofilm formation

    Directory of Open Access Journals (Sweden)

    Mohammad Hassani Sangani

    2015-04-01

    Full Text Available Objective(s: Bacterial biofilm formation causes many persistent and chronic infections. The matrix protects biofilm bacteria from exposure to innate immune defenses and antibiotic treatments. The purpose of this study was to evaluate the biofilm formation of clinical isolates of Pseudomonas aeruginosa and the activity of zinc oxide nanoparticles (ZnO NPs on biofilm. Materials and Methods: After collecting bacteria from clinical samples of hospitalized patients, the ability of organisms were evaluated to create biofilm by tissue culture plate (TCP assay. ZnO NPs were synthesized by sol gel method and the efficacy of different concentrations (50- 350 µg/ml of ZnO NPs was assessed on biofilm formation and also elimination of pre-formed biofilm by using TCP method. Results:The average diameter of synthesized ZnO NPs was 20 nm. The minimum inhibitory concentration of nanoparticles was 150- 158 μg/ml and the minimum bactericidal concentration was higher (325 µg/ml. All 15 clinical isolates of P. aeruginosa were able to produce biofilm. Treating the organisms with nanoparticles at concentrations of 350 μg/ml resulted in more than 94% inhibition in OD reduction%. Molecular analysis showed that the presence of mRNA of pslA gene after treating bacteria with ZnO NPs for 30 minutes. Conclusion: The results showed that ZnO NPs can inhibit the establishment of P. aeruginosa biofilms and have less effective in removing pre-formed biofilm. However the tested nanoparticles exhibited anti-biofilm effect, but mRNA of pslA gene could be still detected in the medium by RT-PCR technique after 30 minutes treatment with ZnO.

  8. Bifunctional silica nanoparticles for the exploration of biofilms of Pseudomonas aeruginosa.

    Science.gov (United States)

    Mauline, L; Gressier, M; Roques, C; Hammer, P; Ribeiro, S J L; Caiut, J M A; Menu, M-J

    2013-01-01

    Luminescent silica nanoparticles are frequently employed for biotechnology applications mainly because of their easy functionalization, photo-stability, and biocompatibility. Bifunctional silica nanoparticles (BSNPs) are described here as new efficient tools for investigating complex biological systems such as biofilms. Photoluminescence is brought about by the incorporation of a silylated ruthenium(II) complex. The surface properties of the silica particles were designed by reaction with amino-organosilanes, quaternary ammonium-organosilanes, carboxylate-organosilanes and hexamethyldisilazane. BSNPs were characterized extensively by DRIFT, (13)C and (29)Si solid state NMR, XPS, and photoluminescence. Zeta potential and contact angle measurements exhibited various surface properties (hydrophilic/hydrophobic balance and electric charge) according to the functional groups. Confocal laser scanning microscopy (CLSM) measurements showed that the spatial distribution of these nanoparticles inside a biofilm of Pseudomonas aeruginosa PAO1 depends more on their hydrophilic/hydrophobic characteristics than on their size. CLSM observations using two nanosized particles (25 and 68 nm) suggest that narrow diffusion paths exist through the extracellular polymeric substances matrix. PMID:23805884

  9. Biogenic synthesis of silver nanoparticles using guava (Psidium guajava) leaf extract and its antibacterial activity against Pseudomonas aeruginosa

    Science.gov (United States)

    Bose, Debadin; Chatterjee, Someswar

    2015-09-01

    Among the various inorganic nanoparticles, silver nanoparticles have received substantial attention in the field of antimicrobial research. For safe and biocompatible use of silver nanoparticles in antimicrobial research, the different biogenic routes are developed to synthesize silver nanoparticles that do not use toxic chemicals. Among those, to synthesize silver nanoparticles, the use of plant part extract becomes an emerging field because plant part acts as reducing as well as capping agent. For large-scale production of antibacterial silver nanoparticles using plant part, the synthesis route should be very simple, rapid, cost-effective and environment friendly based on easy availability and non-toxic nature of plant, stability and antibacterial potential of biosynthesized nanoparticles. In the present study, we report a very simple, rapid, cost-effective and environment friendly route for green synthesis of silver nanoparticles using guava (Psidium guajava) leaf extract as reducing as well as capping agent. This plant has been opted for the present study for its known medicinal properties, and it is easily available in all seasons and everywhere. The biosynthesized silver nanoparticles are characterized by UV-Vis and TEM analysis. The average particle size is 40 nm in the range of 10-90 nm. The antibacterial activity of these nanoparticles against Pseudomonas aeruginosa MTCC 741 has been measured by disc diffusion method, agar cup assay and serial dilution turbidity measurement assay. The results show that green synthesized silver nanoparticles, using guava (Psidium guajava) leaf extract, have a potential to inhibit the growth of bacteria.

  10. Biogenic synthesis of silver nanoparticles using guava ( Psidium guajava) leaf extract and its antibacterial activity against Pseudomonas aeruginosa

    Science.gov (United States)

    Bose, Debadin; Chatterjee, Someswar

    2016-08-01

    Among the various inorganic nanoparticles, silver nanoparticles have received substantial attention in the field of antimicrobial research. For safe and biocompatible use of silver nanoparticles in antimicrobial research, the different biogenic routes are developed to synthesize silver nanoparticles that do not use toxic chemicals. Among those, to synthesize silver nanoparticles, the use of plant part extract becomes an emerging field because plant part acts as reducing as well as capping agent. For large-scale production of antibacterial silver nanoparticles using plant part, the synthesis route should be very simple, rapid, cost-effective and environment friendly based on easy availability and non-toxic nature of plant, stability and antibacterial potential of biosynthesized nanoparticles. In the present study, we report a very simple, rapid, cost-effective and environment friendly route for green synthesis of silver nanoparticles using guava ( Psidium guajava) leaf extract as reducing as well as capping agent. This plant has been opted for the present study for its known medicinal properties, and it is easily available in all seasons and everywhere. The biosynthesized silver nanoparticles are characterized by UV-Vis and TEM analysis. The average particle size is 40 nm in the range of 10-90 nm. The antibacterial activity of these nanoparticles against Pseudomonas aeruginosa MTCC 741 has been measured by disc diffusion method, agar cup assay and serial dilution turbidity measurement assay. The results show that green synthesized silver nanoparticles, using guava ( Psidium guajava) leaf extract, have a potential to inhibit the growth of bacteria.

  11. Analysis of Pseudomonas aeruginosa Cell Envelope Proteome by Capture of Surface-Exposed Proteins on Activated Magnetic Nanoparticles

    OpenAIRE

    Davide Vecchietti; Dario Di Silvestre; Matteo Miriani; Francesco Bonomi; Mauro Marengo; Alessandra Bragonzi; Lara Cova; Eleonora Franceschi; Pierluigi Mauri; Giovanni Bertoni

    2012-01-01

    We report on specific magneto-capturing followed by Multidimensional Protein Identification Technology (MudPIT) for the analysis of surface-exposed proteins of intact cells of the bacterial opportunistic pathogen Pseudomonas aeruginosa. The magneto-separation of cell envelope fragments from the soluble cytoplasmic fraction allowed the MudPIT identification of the captured and neighboring proteins. Remarkably, we identified 63 proteins captured directly by nanoparticles and 67 proteins embedde...

  12. Delivery of tobramycin coupled to iron oxide nanoparticles across the biofilm of mucoidal Pseudonomas aeruginosa and investigation of its efficacy

    Science.gov (United States)

    Armijo, Leisha M.; Kopciuch, Michael; Olszá½¹wka, Zuzia; Wawrzyniec, Stephen J.; Rivera, Antonio C.; Plumley, John B.; Cook, Nathaniel C.; Brandt, Yekaterina I.; Huber, Dale L.; Smolyakov, Gennady A.; Adolphi, Natalie L.; Smyth, Hugh D. C.; Osiński, Marek

    2014-03-01

    Pseudomonas aeruginosa bacterium is a deadly pathogen, leading to respiratory failure in cystic fibrosis and nosocomial pneumonia, and responsible for high mortality rates in these diseases. P. aeruginosa has inherent as well as acquired resistance to many drug classes. In this paper, we investigate the effectiveness of two classes; aminoglycoside (tobramycin) and fluoroquinolone (ciprofloxacin) administered alone, as well as conjugated to iron oxide (magnetite) nanoparticles. P. aeruginosa possesses the ability to quickly alter its genetics to impart resistance to the presence of new, unrecognized treatments. As a response to this impending public health threat, we have synthesized and characterized magnetite nanoparticles capped with biodegradable short-chain carboxylic acid derivatives conjugated to common antibiotic drugs. The functionalized nanoparticles may carry the drug past the mucus and biofilm layers to target the bacterial colonies via magnetic gradient-guided transport. Additionally, the magnetic ferrofluid may be used under application of an oscillating magnetic field to raise the local temperature, causing biofilm disruption, slowed growth, and mechanical disruption. These abilities of the ferrofluid would also treat multi-drug resistant strains, which appear to be increasing in many nosocomial as well as acquired opportunistic infections. In this in vitro model, we show that the iron oxide alone can also inhibit bacterial growth and biofilm formation.

  13. Silver Nanoparticles: Biosynthesis Using an ATCC Reference Strain of Pseudomonas aeruginosa and Activity as Broad Spectrum Clinical Antibacterial Agents

    Science.gov (United States)

    Quinteros, Melisa A.; Aiassa Martínez, Ivana M.; Dalmasso, Pablo R.; Páez, Paulina L.

    2016-01-01

    Currently, the biosynthesis of silver-based nanomaterials attracts enormous attention owing to the documented antimicrobial properties of these ones. This study reports the extracellular biosynthesis of silver nanoparticles (Ag-NPs) using a Pseudomonas aeruginosa strain from a reference culture collection. A greenish culture supernatant of P. aeruginosa incubated at 37°C with a silver nitrate solution for 24 h changed to a yellowish brown color, indicating the formation of Ag-NPs, which was confirmed by UV-vis spectroscopy, transmission electron microscopy, and X-ray diffraction. TEM analysis showed spherical and pseudospherical nanoparticles with a distributed size mainly between 25 and 45 nm, and the XRD pattern revealed the crystalline nature of Ag-NPs. Also it provides an evaluation of the antimicrobial activity of the biosynthesized Ag-NPs against human pathogenic and opportunistic microorganisms, namely, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Proteus mirabilis, Acinetobacter baumannii, Escherichia coli, P. aeruginosa, and Klebsiella pneumonia. Ag-NPs were found to be bioactive at picomolar concentration levels showing bactericidal effects against both Gram-positive and Gram-negative bacterial strains. This work demonstrates the first helpful use of biosynthesized Ag-NPs as broad spectrum bactericidal agents for clinical strains of pathogenic multidrug-resistant bacteria such as methicillin-resistant S. aureus, A. baumannii, and E. coli. In addition, these Ag-NPs showed negligible cytotoxic effect in human neutrophils suggesting low toxicity to the host. PMID:27340405

  14. Induction of humoral immune response against Pseudomonas aeruginosa flagellin(1-161) using gold nanoparticles as an adjuvant.

    Science.gov (United States)

    Dakterzada, Farida; Mohabati Mobarez, Ashraf; Habibi Roudkenar, Mehryar; Mohsenifar, Afshin

    2016-03-14

    Flagellin of Pseudomonas aeruginosa is an important vaccine candidate. N-terminal domains are highly conserved in both type a and type b flagellins. The efficacy of gold nanoparticles (AuNPs) conjugated to N-terminal domains of P. aeruginosa flagellin (flagellin(1-161)), as an immunogen in mice, has been assessed. The nanoparticles were conjugated to the recombinant protein through direct interaction of thiol molecules of the cysteines with AuNPs and formation of AuS bond. Flagellin(1-161), AuNP-flagellin(1-161), and flagellin(1-161) emulsified in Freund's adjuvant (FA: complete/incomplete Freund's adjuvant formulation) were administered subcutaneously to BALB/c mice. Mice given AuNP-flagellin(1-161) elicited high titers of anti-flagellin(1-161) antibodies compared with non-immune group and/or mice which received flagellin(1-161) without adjuvant. In whole cell ELISA, these antibodies effectively recognized the native flagellin on the bacteria. Opsonophagocytosis assay demonstrated the functional activity and specificity of anti-flagellin(1-161) antibodies raised by AuNP-flagellin(1-161) against homologous strain. All of the results were comparable with those obtained by use of FA. Taken together, this is the first report of conjugation of AuNPs to flagellin and evaluating its immune response against P. aeruginosa. PMID:26868080

  15. Analysis of Pseudomonas aeruginosa cell envelope proteome by capture of surface-exposed proteins on activated magnetic nanoparticles.

    Directory of Open Access Journals (Sweden)

    Davide Vecchietti

    Full Text Available We report on specific magneto-capturing followed by Multidimensional Protein Identification Technology (MudPIT for the analysis of surface-exposed proteins of intact cells of the bacterial opportunistic pathogen Pseudomonas aeruginosa. The magneto-separation of cell envelope fragments from the soluble cytoplasmic fraction allowed the MudPIT identification of the captured and neighboring proteins. Remarkably, we identified 63 proteins captured directly by nanoparticles and 67 proteins embedded in the cell envelope fragments. For a high number of proteins, our analysis strongly indicates either surface exposure or localization in an envelope district. The localization of most identified proteins was only predicted or totally unknown. This novel approach greatly improves the sensitivity and specificity of the previous methods, such as surface shaving with proteases that was also tested on P. aeruginosa. The magneto-capture procedure is simple, safe, and rapid, and appears to be well-suited for envelope studies in highly pathogenic bacteria.

  16. Overcoming barriers in Pseudomonas aeruginosa lung infections: Engineered nanoparticles for local delivery of a cationic antimicrobial peptide.

    Science.gov (United States)

    d'Angelo, Ivana; Casciaro, Bruno; Miro, Agnese; Quaglia, Fabiana; Mangoni, Maria Luisa; Ungaro, Francesca

    2015-11-01

    Cationic antimicrobial peptides (CAMPs) are very promising in the treatment of multi-drug resistant Pseudomonas aeruginosa lung infections experienced by cystic fibrosis (CF) patients. Nevertheless, there is an urgent need of inhalable formulations able to deliver the intact CAMP in conductive airways and to shield its interactions with airway mucus/bacterial biofilm, thus enhancing CAMP/bacteria interactions. Along these lines, the aim of this work was the design and development of nano-embedded microparticles (NEM) for sustained delivery of CAMPs in the lung. To this purpose, nanoparticles (NPs) made of poly(lactide-co-glycolide) (PLGA) containing a model CAMP, colistin (Col), were produced by emulsion/solvent diffusion technique. Engineering NPs with chitosan (CS) and poly(vinyl alcohol) (PVA) allowed to modulate surface properties and, in so doing, to improve NP transport through artificial CF mucus. In order to achieve a long-term stable dosage form useful for NP inhalation, NPs were spray-dried in different carriers (lactose or mannitol), thus producing NEM. The most promising NEM formulations were selected on the basis of bulk and flow properties, distribution of NPs in the carrier and aerosolization performance upon delivery through a breath-actuated dry powder inhaler. Of note, selected Col-loaded NEM were found to kill P. aeruginosa biofilm and to display a prolonged efficacy in biofilm eradication compared to the free Col. This effect was likely ascribable to the ability of NPs to penetrate into bacterial biofilm, as demonstrated by confocal analysis, and to sustain Col release inside it. Taken all together, our results indicate that adequate engineering of PLGA NPs represents an enticing technological approach to harness novel antimicrobials for P. aeruginosa lung infection, such as CAMPs, especially in CF. PMID:26340361

  17. In vitro and in vivo antimicrobial activity of combined therapy of silver nanoparticles and visible blue light against Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Nour El Din S

    2016-04-01

    Full Text Available Suzanne Nour El Din,1 Tarek A El-Tayeb,2 Khaled Abou-Aisha,1 Mohamed El-Azizi1 1Department of Microbiology, Immunology and Biotechnology, Faculty of Pharmacy and Biotechnology, German University in Cairo, 2National Institute for Laser Enhanced Sciences, Cairo University, Cairo, Egypt Abstract: Silver nanoparticles (AgNPs have been used as potential antimicrobial agents against resistant pathogens. We investigated the possible therapeutic use of AgNPs in combination with visible blue light against a multidrug resistant clinical isolate of Pseudomonas aeruginosa in vitro and in vivo. The antibacterial activity of AgNPs against P. aeruginosa (1×105 colony forming unit/mL was investigated at its minimal inhibitory concentration (MIC and sub-MIC, alone and in combination with blue light at 460 nm and 250 mW for 2 hours. The effect of this combined therapy on the treated bacteria was then visualized using transmission electron microscope. The therapy was also assessed in the prevention of biofilm formation by P. aeruginosa on AgNP-impregnated gelatin biopolymer discs. Further, in vivo investigations were performed to evaluate the efficacy of the combined therapy to prevent burn-wound colonization and sepsis in mice and, finally, to treat a real infected horse with antibiotic-unresponsive chronic wound. The antimicrobial activity of AgNPs and visible blue light was significantly enhanced (P<0.001 when both agents were combined compared to each agent alone when AgNPs were tested at MIC, 1/2, or 1/4 MIC. Transmission electron microscope showed significant damage to the cells that were treated with the combined therapy compared to other cells that received either the AgNPs or blue light. In addition, the combined treatment significantly (P<0.001 inhibited biofilm formation by P. aeruginosa on gelatin discs compared to each agent individually. Finally, the combined therapy effectively treated a horse suffering from a chronic wound caused by mixed

  18. Pyocyanine Biosynthetic Genes in Clinical and Environmental Isolates of Pseudomonas aeruginosa and Detection of Pyocyanine’s Antimicrobial Effects with or without Colloidal Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Afrooz Rashnonejad

    2012-01-01

    Full Text Available Objective: Pyocyanine plays an important role in the pathogenesis of Pseudomonas aeruginosa, (P. aeruginosa and is known to have inhibitory and bactericidal effects. This study has aimed to detect the phenazine biosynthetic operon (phz ABCDEFG and two phenazine modifying genes (phzM and phzS by polymerase chain reaction (PCR and detection of its possible protein bands by sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE. The antimicrobial effects of pyocyanine alone and mixed with colloidal silver nanoparticles were studied.Materials and Methods: In this descriptive study, clinical and environmental species of P. aeruginosa were isolated by thioglycollate medium culture and cetrimide agar, respectively. The existence of a phenazine biosynthetic operon and two phenazine modifying genes as well as their protein products were confirmed by PCR and SDS-PAGE, respectively. Pyocyanine was extracted with chloroform and its antimicrobial effects against bacteria such as; Escherichia coli (E. coli, P. aeruginosaand Staphylococcus aureus (S. aureus bacteria and yeast Candida albicans (C. albicans were tested using well, spot and disk diffusion methods.Results: In this study, 3 out of 48 clinical strains were unable to produce pyocyanine on cetrimide and Mueller Hinton (MH agar. Two strains did not have phenazine modifying gene bands. Another strain did not have the possible protein band of the phzM gene. Pyocyanine had antimicrobial effects against the microbial strains, which increased in the presence of silver nanoparticles.Conclusion: According to the results of the present study, some P. aeruginosa strains are unable to produce pyocyanine due to the absence of the phzM or phzS genes. Therefore, these genes have an important role in pyocyanine production in P. aeruginosa. Pyocyanine shows synergistic antimicrobial effects in the presence of silver nanoparticles against microbial strains.

  19. Room temperature biogenic synthesis of multiple nanoparticles (Ag, Pd, Fe, Rh, Ni, Ru, Pt, Co, and Li) by Pseudomonas aeruginosa SM1

    International Nuclear Information System (INIS)

    Room temperature biosynthesis of Ag, Pd, Fe, Rh, Ni, Ru, Pt, Co, and Li nanoparticles was achieved using Pseudomonas aeruginosa SM1 without the addition of growth media, electron donors, stabilizing agents, preparation of cell/cell-free extract or temperature, and pH adjustments. The resulting nanoparticles were characterized by Transmission electron microscopy and X-ray diffraction. It was observed that P. aeruginosa SM1 is capable of producing both intracellular (Co and Li) and extracellular (Ag, Pd, Fe, Rh, Ni, Ru, and Pt) nanoparticles in both crystalline and amorphous state. The FT-IR spectra clearly showed the presence of primary and secondary amines which may be responsible for the reduction and subsequent stabilization of the resulting extracellular nanoparticles which were obtained as a one-step process. This suggests toward an unknown “selection mechanism” that reduces certain metal ions and allows others to enter the cell membrane. Finally, in this first of its kind study, single strain of bacteria was used to produce several different mono-metallic nanoparticles.

  20. Room temperature biogenic synthesis of multiple nanoparticles (Ag, Pd, Fe, Rh, Ni, Ru, Pt, Co, and Li) by Pseudomonas aeruginosa SM1

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Sarvesh Kumar; Constanti, Magda, E-mail: magdalena.constanti@urv.cat [Universitat Rovira i Virgili, Departament d' Enginyeria Quimica (Spain)

    2012-03-15

    Room temperature biosynthesis of Ag, Pd, Fe, Rh, Ni, Ru, Pt, Co, and Li nanoparticles was achieved using Pseudomonas aeruginosa SM1 without the addition of growth media, electron donors, stabilizing agents, preparation of cell/cell-free extract or temperature, and pH adjustments. The resulting nanoparticles were characterized by Transmission electron microscopy and X-ray diffraction. It was observed that P. aeruginosa SM1 is capable of producing both intracellular (Co and Li) and extracellular (Ag, Pd, Fe, Rh, Ni, Ru, and Pt) nanoparticles in both crystalline and amorphous state. The FT-IR spectra clearly showed the presence of primary and secondary amines which may be responsible for the reduction and subsequent stabilization of the resulting extracellular nanoparticles which were obtained as a one-step process. This suggests toward an unknown 'selection mechanism' that reduces certain metal ions and allows others to enter the cell membrane. Finally, in this first of its kind study, single strain of bacteria was used to produce several different mono-metallic nanoparticles.

  1. Bifunctional silica nanoparticles for the exploration of biofilms of Pseudomonas aeruginosa

    OpenAIRE

    Mauline, Léïla; Gressier, Marie; Roques, Christine; Hammer, Peter,; Ribeiro, Sidney J. L.; Caiut, José Maurício A.; Menu, Marie-Joëlle

    2013-01-01

    Luminescent silica nanoparticles are frequently employed for biotechnology applications mainly because of their easy functionalization, photo-stability, and biocompatibility. Bifunctional silica nanoparticles (BSNPs) are described here as new efficient tools for investigating complex biological systems such as biofilms. Photoluminescence is brought about by the incorporation of a silylated ruthenium (II) complex. The surface properties of the silica particles were designed by reaction with am...

  2. Capacitive sensing of microcystin variants of Microcystis aeruginosa using a gold immunoelectrode modified with antibodies, gold nanoparticles and polytyramine

    International Nuclear Information System (INIS)

    We report on the application of an automated and easy-to-use device to directly measure the immunoreactions between adda-specific monoclonal antibodies and microcystins. The antibodies were immobilized on a gold electrode whose surface was modified first with polytyramine and then with gold nanoparticles. The immunoreaction leads to a change in the capacitance of the system. Under optimum conditions, the sensor is capable of performing stable regeneration-assay cycles and has a low detection limit at a concentration of 0.01 pM level of microcystin-leucine-arginine (MC-LR). The surface of the biosensor can be regenerated with pH 2.5 glycine buffer which dissociates the antibody-antigen complex. The biosensor was used to monitor the production of microcystins during batch cultivation of Microcystis aeruginosa (isolated from ponds in Botswana). Liquid chromatography coupled to MS/MS detection was used to identify three variants, viz. MC-LR (995.6 Da), DmMC-LR (981.2 Da) and MC-LA (910.5 Da). (author)

  3. Acute exposure to silica nanoparticles enhances mortality and increases lung permeability in a mouse model of Pseudomonas aeruginosa pneumonia

    OpenAIRE

    Delaval, Mathilde; Boland, Sonja; Solhonne, Brigitte; Nicola, Marie-Anne; Mornet, Stéphane; Baeza-Squiban, Armelle; Sallenave, Jean-Michel; Garcia-Verdugo, Ignacio

    2015-01-01

    Background The lung epithelium constitutes the first barrier against invading pathogens and also a major surface potentially exposed to nanoparticles. In order to ensure and preserve lung epithelial barrier function, the alveolar compartment possesses local defence mechanisms that are able to control bacterial infection. For instance, alveolar macrophages are professional phagocytic cells that engulf bacteria and environmental contaminants (including nanoparticles) and secrete pro-inflammator...

  4. In vitro and in vivo antimicrobial activity of combined therapy of silver nanoparticles and visible blue light against Pseudomonas aeruginosa

    OpenAIRE

    Nour El Din S; El-Tayeb TA; Abou-Aisha K; El-Azizi M

    2016-01-01

    Suzanne Nour El Din,1 Tarek A El-Tayeb,2 Khaled Abou-Aisha,1 Mohamed El-Azizi1 1Department of Microbiology, Immunology and Biotechnology, Faculty of Pharmacy and Biotechnology, German University in Cairo, 2National Institute for Laser Enhanced Sciences, Cairo University, Cairo, Egypt Abstract: Silver nanoparticles (AgNPs) have been used as potential antimicrobial agents against resistant pathogens. We investigated the possible therapeutic use of AgNPs in combination with visible blue light ...

  5. Pseudomonas aeruginosa biofilm infections

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim

    2014-01-01

    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...

  6. nanoparticles

    Science.gov (United States)

    Andreu-Cabedo, Patricia; Mondragon, Rosa; Hernandez, Leonor; Martinez-Cuenca, Raul; Cabedo, Luis; Julia, J. Enrique

    2014-10-01

    Thermal energy storage (TES) is extremely important in concentrated solar power (CSP) plants since it represents the main difference and advantage of CSP plants with respect to other renewable energy sources such as wind, photovoltaic, etc. CSP represents a low-carbon emission renewable source of energy, and TES allows CSP plants to have energy availability and dispatchability using available industrial technologies. Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 500°C. Their main drawbacks are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve thermal properties of fluids is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. In this work, solar salt used in CSP plants (60% NaNO3 + 40% KNO3) was doped with silica nanoparticles at different solid mass concentrations (from 0.5% to 2%). Specific heat was measured by means of differential scanning calorimetry (DSC). A maximum increase of 25.03% was found at an optimal concentration of 1 wt.% of nanoparticles. The size distribution of nanoparticle clusters present in the salt at each concentration was evaluated by means of scanning electron microscopy (SEM) and image processing, as well as by means of dynamic light scattering (DLS). The cluster size and the specific surface available depended on the solid content, and a relationship between the specific heat increment and the available particle surface area was obtained. It was proved that the mechanism involved in the specific heat increment is based on a surface phenomenon. Stability of samples was tested for several thermal cycles and thermogravimetric analysis at high temperature was carried out, the samples being stable.

  7. 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...

  8. Pseudomonas aeruginosa in Healthcare Settings

    Science.gov (United States)

    ... CDC.gov . Healthcare-associated Infections (HAIs) Share Compartir Pseudomonas aeruginosa in Healthcare Settings On this Page What ... and/or help treat infections? What is a Pseudomonas infection? Pseudomonas infection is caused by strains of ...

  9. 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, but that the...... silver concentration is important. A concentration of 5-10 ig/mL silver sulfadiazine eradicated the biofilm whereas a lower concentration (1 ig/mL) had no effect. The bactericidal concentration of silver required to eradicate the bacterial biofilm was 10-100 times higher than that used to eradicate...... planktonic bacteria. These observations strongly indicate that the concentration of silver in currently available wound dressings is much too low for treatment of chronic biofilm wounds. It is suggested that clinicians and manufacturers of the said wound dressings consider whether they are treating wounds...

  10. Phosphate taxis in Pseudomonas aeruginosa.

    OpenAIRE

    Kato, J.; Ito, A.; Nikata, T; Ohtake, H

    1992-01-01

    Pseudomonas aeruginosa was shown to be attracted to phosphate. The chemotactic response was induced by phosphate starvation. The specificity of chemoreceptors for phosphate was high so that no other tested phosphorus compounds elicited a chemotactic response as strong as that elicited by phosphate. Competition experiments showed that the chemoreceptors for phosphate appeared to be different from those for the common amino acids. Mutants constitutive for alkaline phosphatase showed the chemota...

  11. 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%.

  12. Innate immune responses to Pseudomonas aeruginosa infection

    OpenAIRE

    Lavoie, Elise G.; Wangdi, Tamding; Kazmierczak, Barbara I.

    2011-01-01

    Innate immune responses play a critical role in controlling acute infections due to Pseudomonas aeruginosa in both mice and in humans. In this review we focus on innate immune recognition and clearance mechanisms that are important for controlling P. aeruginosa in the mammalian lung, with particular attention to those that influence the outcome of in vivo infection in murine models.

  13. Versatile cloning vector for Pseudomonas aeruginosa.

    OpenAIRE

    Wood, D O; Hollinger, M F; Tindol, M B

    1981-01-01

    A pBR322:RSF1010 composite plasmid, constructed in vitro, was used as a cloning vector in Pseudomonas aeruginosa. This nonamplifiable plasmid, pMW79, has a molecular weight of 8.4 X 10(6) and exists as a multicopy plasmid in both P. aeruginosa and Escherichia coli. In P. aeruginosa strain PAO2003, pMW79 conferred resistance to carbenicillin and tetracycline. Characterization of pMW79 with restriction enzymes revealed that four enzymes (BamHI, SalI, HindIII, and HpaI) cleaved the plasmid at un...

  14. Suppression of Aspergillus by Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

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

    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......, here among 2-heptyl-3-hydroxy-4-quinolone (PQS). An unidentified green pseudomonas compound was also observed. Interestingly the P. aeruginosa mutant rpoN was unable to suppress A. fumigatus, but suppressed A. flavus, A. oryzae and A. niger. However several other P. aeruginosa mutants suppressed A...

  15. Antimicrobial activity and the mechanism of silver nanoparticle thermosensitive gel

    OpenAIRE

    Chen, Meiwan; Yang, Zhiwen; Wu, Hongmei; Pan, Xin; XIE, XIAOBAO; Wu, Chuanbin

    2011-01-01

    Purpose The purpose of the present study was to elucidate the antimicrobial activity and mechanism of silver nanoparticles incorporated into thermosensitive gel (S-T-Gel) on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Patients and methods This study investigated the growth, permeability, and morphology of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa cells in order to observe the action of S-T-Gel on the membrane structure of these three bacteria...

  16. 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.

  17. Biofilm dispersion in Pseudomonas aeruginosa.

    Science.gov (United States)

    Kim, Soo-Kyoung; Lee, Joon-Hee

    2016-02-01

    In recent decades, many researchers have written numerous articles about microbial biofilms. Biofilm is a complex community of microorganisms and an example of bacterial group behavior. Biofilm is usually considered a sessile mode of life derived from the attached growth of microbes to surfaces, and most biofilms are embedded in self-produced extracellular matrix composed of extracellular polymeric substances (EPSs), such as polysaccharides, extracellular DNAs (eDNA), and proteins. Dispersal, a mode of biofilm detachment indicates active mechanisms that cause individual cells to separate from the biofilm and return to planktonic life. Since biofilm cells are cemented and surrounded by EPSs, dispersal is not simple to do and many researchers are now paying more attention to this active detachment process. Unlike other modes of biofilm detachment such as erosion or sloughing, which are generally considered passive processes, dispersal occurs as a result of complex spatial differentiation and molecular events in biofilm cells in response to various environmental cues, and there are many biological reasons that force bacterial cells to disperse from the biofilms. In this review, we mainly focus on the spatial differentiation of biofilm that is a prerequisite for dispersal, as well as environmental cues and molecular events related to the biofilm dispersal. More specifically, we discuss the dispersal-related phenomena and mechanisms observed in Pseudomonas aeruginosa, an important opportunistic human pathogen and representative model organism for biofilm study. PMID:26832663

  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. Clonal complex Pseudomonas aeruginosa in horses.

    Science.gov (United States)

    Kidd, Timothy J; Gibson, Justine S; Moss, Susan; Greer, Ristan M; Cobbold, Rowland N; Wright, John D; Ramsay, Kay A; Grimwood, Keith; Bell, Scott C

    2011-05-01

    Pseudomonas aeruginosa is associated with infectious endometritis in horses. Although infectious endometritis is often considered a venereal infection, there is relatively limited genotypic-based evidence to support this mode of transmission. The study sought to determine the relatedness between genital P. aeruginosa isolates collected from a limited geographical region using molecular strain typing. Enterobacterial repetitive intergenic consensus PCR typing was performed on 93 isolates collected between 2005 and 2009 from 2058 thoroughbred horses (including 18 stallions) at 66 studs. While P. aeruginosa was not detected in the stallions, 53/93 (57%) mares harbouring P. aeruginosa had clonally related strains, which included a single dominant genotype detected in 42 (45%) mares from 13 different studs. These novel findings suggest that most equine genital P. aeruginosa infections in this region may have been acquired from mechanisms other than direct horse to horse transmission. Instead, other potential acquisition pathways, as well as strain specific adaptation to the equine genital tract, should be investigated. PMID:21183294

  20. 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....

  1. 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......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...

  2. 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...

  3. Aspergillus triggers phenazine production in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

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

    Objectives: Pseudomonas aeruginosa is an opportunistic human pathogen, commonly infecting cystic fibrosis (CF) patients. Aspergilli, especially Aspergillus fumigatus, are also frequently isolated from CF patients. Our aim was to examine the possible interaction between P. aeruginosa and different...... the contact area of A. niger, A. flavus, A. oryzae, but not A. fumigatus. In addition, other metabolites with UV chromophores similar to the phenazines were only found in the contact zone between Aspergillus and Pseudomonas. No change in secondary metabolite profiles were seen for the Aspergilli, when...... comparing with or without the presence of Pseudomonas. Conclusion: All Aspergilli tested, with the exception of A. fumigatus, triggered the upregulation of phenazine-1-carboxamide and phenazine-1-carboxylic acid production by P. aeruginosa. Surprisingly no changes in secondary metabolite profiles were...

  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. Spaceflight Effects on Virulence of Pseudomonas Aeruginosa

    Science.gov (United States)

    Broadway, S.; Goins, T.; Crandell, C.; Richards, C.; Patel, M.; Pyle, B.

    2008-06-01

    Pseudomonas aeruginosa is an opportunistic pathogen found in the environment. It is known to infect the immunocompromised. The organism has about 25 virulence genes that play different roles in disease processes. Several exotoxin proteins may be produced, including ExoA, ExoS, ExoT and ExoY, and other virulence factors. In spaceflight, possible increased expression of P. aeruginosa virulence proteins could increase health risks for spaceflight crews who experience decreased immunity. Cultures of P. aeruginosa strains PA01 and PA103 grown on orbit on Shuttle Endeavour flight STS-123 vs. static ground controls were used for analysis. The production of ETA was quantitated using an ELISA procedure. Results showed that while flight cultures of PA103 produced slightly more ETA than corresponding ground controls, the opposite was found for PA01. While it appears that spaceflight has little effect on ETA, stimulation of other virulence factors could cause increased virulence of this organism in space flight. Similar increased virulence in spaceflight has been observed for other bacteria. This is important because astronauts may be more susceptible to opportunistic pathogens including P. aeruginosa.

  6. Pseudomonas aeruginosa biofilms in cystic fibrosis

    DEFF Research Database (Denmark)

    Høiby, Niels; Ciofu, Oana; Bjarnsholt, Thomas

    2010-01-01

    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 and...

  7. 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.

  8. [Macrolides, Pseudomonas aeruginosa and cystic fibrosis].

    Science.gov (United States)

    Guillot, M; Amiour, M; El Hachem, C; Harchaoui, S; Ribault, V; Paris, C

    2006-10-01

    Long-term low dose azithromycin treatment in cystic fibrosis patients with chronic Pseudomonas aeruginosa infection is safe and reduces the decline in lung function, the number of acute exacerbations and improves nutritional status; underlying efficacy mechanisms are multiple and synergistic. PMID:17370396

  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. 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....... 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 of...... P. aeruginosa at concentrations as low as 0.25%. Oral administration of ginseng extracts in mice promoted phagocytosis of P. aeruginosa PAO1 by airway phagocytes, but did not affect phagocytosis of a PAO1-filM mutant. Our study suggests that ginseng treatment may help to eradicate the biofilm...

  11. 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...

  12. 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.

  13. 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....... Although 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....

  14. Proteolytic inactivation of cytokines by Pseudomonas aeruginosa.

    OpenAIRE

    Parmely, M; Gale, A; Clabaugh, M.; Horvat, R; Zhou, W W

    1990-01-01

    Pseudomonas aeruginosa alkaline protease and elastase are thought to contribute to bacterial invasiveness, tissue damage, and immune suppression in animals and patients infected with the bacterium. This study examined the ability of the two proteases to inactivate a number of cytokines that mediate immune and inflammatory responses. Human recombinant gamma interferon (rIFN-gamma) and human recombinant tumor necrosis factor alpha were inactivated by both proteases. Murine rIFN-gamma was relati...

  15. Iron and Pseudomonas aeruginosa biofilm formation

    OpenAIRE

    Banin, Ehud; Vasil, Michael L.; Greenberg, E. Peter

    2005-01-01

    Iron serves as a signal in Pseudomonas aeruginosa biofilm development. We examined the influence of mutations in known and putative iron acquisition-signaling genes on biofilm morphology. In iron-sufficient medium, mutants that cannot obtain iron through the high-affinity pyoverdine iron acquisition system form thin biofilms similar to those formed by the parent under low iron conditions. If an iron source for a different iron acquisition system is provided to a pyoverdine mutant, normal biof...

  16. Interaction between biofilms formed by Pseudomonas aeruginosa and clarithromycin.

    OpenAIRE

    Yasuda, H; Ajiki, Y; Koga, T.; Kawada, H; Yokota, T.

    1993-01-01

    Interactions between bacterial biofilms formed by Pseudomonas aeruginosa and clarithromycin, a macrolide having no anti-P. aeruginosa activity, were investigated. P. aeruginosa incubated for 10 days on membrane filters formed biofilms on the surfaces of the filters. The biofilms were characterized by dense colonizations of bacteria and thick membranous structures that covered the colonies. Treatment of the biofilms with a relatively low concentration of clarithromycin for 5 days resulted in a...

  17. Interleukin-23-Mediated Inflammation in Pseudomonas aeruginosa Pulmonary Infection

    OpenAIRE

    Dubin, Patricia J.; Martz, Ashley; Eisenstatt, Jessica R.; Fox, Michael D.; Logar, Alison; Kolls, Jay K.

    2012-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that is capable of causing acute and chronic pulmonary infection in the immunocompromised host. In the case of cystic fibrosis (CF), chronic P. aeruginosa infection causes increased mortality by promoting overly exuberant airway inflammation and cumulative lung damage. Identifying the key regulators of this inflammation may lead to the development of new therapies that improve P. aeruginosa-related mortality. We report here that interleukin-...

  18. Fecal isolation of Pseudomonas aeruginosa from patients with cystic fibrosis.

    OpenAIRE

    Agnarsson, U; Glass, S; Govan, J R

    1989-01-01

    Fecal isolation of Pseudomonas aeruginosa was observed in 8 of 10 patients with cystic fibrosis who at the time of sampling also exhibited colonization of the respiratory tract. In contrast, P. aeruginosa cells were isolated at low frequency (9.1%) from the stools of 44 patients with cystic fibrosis with no previous history of chronic colonization. The results of this study suggest that the gastrointestinal tract is not a significant chronic reservoir of P. aeruginosa prior to pulmonary colon...

  19. 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.

  20. The reduced bioavailability of copper by nano-TiO₂ attenuates the toxicity to Microcystis aeruginosa.

    Science.gov (United States)

    Chen, Jinyuan; Qian, Yi; Li, Herong; Cheng, Yanhong; Zhao, Meirong

    2015-08-01

    Nano-TiO2 is a widely applied nanoparticle (NPs) and co-exists with other pollutants such as heavy metals in aquatic environments. However, minimal knowledge is available concerning the ecological risk of these mixtures. Our study reported that at no toxic effect concentrations of TiO2 nanoparticles (5 mg/L), the toxicity of Cu ions to the algae Microcystis aeruginosa was significantly attenuated by TiO2 nanoparticles. Specifically, the concentration of photosynthetic pigments (i.e., concentration of Chla) increased 37% when comparing only Cu ions treated and the nano-TiO2-Cu co-incubation. The levels of phycocyanin (PC), allophycocyanin (APC), phycoerythrin (PE), and phycobiliprotein (PBPs) were also recovered at levels ranging from 23 to 35% after 72 h. For oxidative indexes, the decreased activities of the superoxide dismutase (SOD), peroxidase (POD) content, and malondialdehyde (MDA) with the existence of nano-TiO2 displayed a lower level compared to Cu ions treatment only at 24 and 48 h. This toxicity attenuation can be confirmed by subcellular structures because the impairment to cellular membranes and organelles reduced with the presence of nano-TiO2. The potential mechanisms of the antagonism between the nano-TiO2 and Cu ions can be partially attributed to the sorption of copper onto TiO2 nanoparticles, which fitted the Freundlich isotherm (coefficient = 0.967). The decreased bioavailability of Cu ions protected algae cells from being attacked by free Cu ions. Given the abundance of released nanoparticles and unique physicochemical property of nanoparticles, our results elucidated the ecosafety of nanoparticles and co-substrates in aquatic systems. PMID:25903177

  1. Point-of-care and visual detection of P. aeruginosa and its toxin genes by multiple LAMP and lateral flow nucleic acid biosensor.

    Science.gov (United States)

    Chen, Yuting; Cheng, Nan; Xu, Yuancong; Huang, Kunlun; Luo, Yunbo; Xu, Wentao

    2016-07-15

    This study describes a simple and sensitive approach for visual and point-of-care detection of P. aeruginosa and its toxin genes based on multiple loop-mediated isothermal amplification (mLAMP) and lateral flow nucleic acid biosensor (LFNAB). Differentiation of the internal standard gene ecfX and toxin genes (ExoS and ExoU) in P. aeruginosa was determined using FITC-, hex-and digoxin-modified primers in the mLAMP process. In the presence of biotin-and FITC- (hex-, digoxin-) modified primers and Bst DNA polymerase large fragments, the mLAMP produced numerous biotin- and FITC- (hex-, digoxin-) attached duplex DNA products. The products were detected by LFNAB through dual immunoreactions (anti-biotin antibodies on the gold nanoparticle (Au-NP) and biotin on the duplex, anti-FITC (hex, digoxin) antibodies on the LFNAB test line and FITC (hex, digoxin) on the duplex). The accumulation of Au-NPs produced a characteristic red band, enabling visual detection of P. aeruginosa and its toxin genes without instrumentation. After systematic optimization of LFNAB preparation and detecting conditions, the current approach was capable of detecting concentrations as low as 20 CFU/mL P. aeruginosa or its toxin genes within 50min without complicated instrument, which is more sensitive than PCR. Therefore, this approach provides a simple, pollution free, sensitive, and low-cost point-of-care test for the detection of P. aeruginosa and its toxin genes. PMID:26985584

  2. 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...

  3. 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...

  4. 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 that...

  5. Occurrence of pseudomonas aeruginosa in post-operative wound infection

    International Nuclear Information System (INIS)

    Objective: To determine the prevalence of Pseudomonas aeruginosa in post-operative wound infection. Results: Out of the 60 bacterial isolates found in post-operative wound infection, 20 (33.3%) were Pseudomonas aeruginosa, followed by Staphylococcus aureus 13(21.7%), Klebsiella species 10(16.7%), Escherichia coli 7(11.7%), Atypical coliform 4(6.7%), Proteus species 4(6.7%), Streptococcus pyogenes 1(1.7%) and Enterococcus faecalis 1(1.7%) in the order. Pseudomonas aeruginosa infections was higher in female than male, ratio 3:2 and was found more among young and elderly debilitated patients. The in vitro sensitivity pattern of 20 isolates of Pseudomonas aeruginosa showed colistin (100%), gentamicin (75%), streptomycin (30%), and tetracycline (10%). Conclusion: The role of Pseudomonas aeruginosa as an agent of nosocomial infection is re-emphasised. (author)

  6. Antibacterial activity of five Peruvian medicinal plants against Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    Gabriela; Ulloa-Urizar; Miguel; Angel; Aguilar-Luis; María; del; Carmen; De; Lama-Odría; José; Camarena-Lizarzaburu; Juana; del; Valle; Mendoza

    2015-01-01

    Objective: To evaluate the susceptibility of Pseudomonas aeruginosa(P. aeruginosa)in vitro to the ethanolic extracts obtained from five different Peruvian medicinal plants.Methods: The plants were chopped and soaked in absolute ethanol(1:2, w/v). The antibacterial activity of compounds against P. aeruginosa was evaluated using the cupplate agar diffusion method.Results: The extracts from Maytenus macrocarpa("Chuchuhuasi"), Dracontium loretense Krause("Jergon Sacha"), Tabebuia impetiginosa("Tahuari"), Eucalyptus camaldulensis Dehn(eucalyptus), Uncaria tomentosa("U?a de gato") exhibited favorable antibacterial activity against P. aeruginosa. The inhibitory effect of the extracts on the strains of P. aeruginosa tested demonstrated that Tabebuia impetiginosa and Maytenus macrocarpa possess higher antibacterial activity.Conclusions: The results of the present study scientifically validate the inhibitory capacity of the five medicinal plants attributed by their common use in folk medicine and contribute towards the development of new treatment options based on natural products.

  7. Antibacterial activity of ifve Peruvian medicinal plants against Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    Gabriela Ulloa-Urizar; Miguel Angel Aguilar-Luis; Mara del Carmen De Lama-Odra; Jos Camarena-Lizarzaburu; Juana del Valle Mendoza

    2015-01-01

    Objective:To evaluate the susceptibility of Pseudomonas aeruginosa (P. aeruginosa) in vitro to the ethanolic extracts obtained from five different Peruvian medicinal plants. Methods:The plants were chopped and soaked in absolute ethanol (1:2, w/v). The antibacterial activity of compounds against P. aeruginosa was evaluated using the cup-plate agar diffusion method. Results:The extracts from Maytenus macrocarpa (“Chuchuhuasi”), Dracontium loretense Krause (“Jergon Sacha”), Tabebuia impetiginosa (“Tahuari”), Eucalyptus camaldulensis Dehn (eucalyptus), Uncaria tomentosa (“Uña de gato”) exhibited favorable antibacterial activity against P. aeruginosa. The inhibitory effect of the extracts on the strains of P. aeruginosa tested demonstrated that Tabebuia impetiginosa and Maytenus macrocarpa possess higher antibacterial activity. Conclusions:The results of the present study scientifically validate the inhibitory capacity of the five medicinal plants attributed by their common use in folk medicine and contribute towards the development of new treatment options based on natural products.

  8. 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...... 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...

  9. Imported PER-1 producing Pseudomonas aeruginosa, PER-1 producing Acinetobacter baumanii and VIM-2-producing Pseudomonas aeruginosa strains in Hungary

    Directory of Open Access Journals (Sweden)

    Nagy Károly

    2008-05-01

    Full Text Available Abstract Introduction Pseudomonas aeruginosa and Acinetobacter baumanii are important nosocomial pathogens with wide intrinsic resistance. However, due to the dissemination of the acquired resistance mechanisms, such as extended-spectrum beta-lactamase (ESBL and metallo beta-lactamase (MBL production, multidrug resistant strains have been isolated more often. Case presentation We report a case of a Hungarian tourist, who was initially hospitalized in Egypt and later transferred to Hungary. On the day of admission PER-1-producing P. aeruginosa, PER-1 producing A. baumannii, SHV-5-producing Klebsiella pneumoniae and VIM-2-producing P. aeruginosa isolates were subcultured from the patient's samples in Hungary. Comparing the pulsed-field gel electrophoresis (PFGE patterns of the P. aeruginosa strains from the patient to the P. aeruginosa strains occurring in this hospital, we can state that the PER-1-producing P. aeruginosa and VIM-2-producing P. aeruginosa had external origin. Conclusion This is the first report of PER-1-producing P. aeruginosa,and PER-1-producing A. baumanii strains in Hungary. This case highlights the importance of spreading of the beta-lactamase-mediated resistance mechanisms between countries and continents, showing the importance of careful screening and the isolation of patients arriving from a different country.

  10. Contributions of efflux pumps to high level resistance of Pseudomonas aeruginosa to ciprofloxacin

    Institute of Scientific and Technical Information of China (English)

    WANG Dan-dan; SUN Tie-ying; HU Yun-jian

    2007-01-01

    @@ Pseudomonas aeruginosa (P. aeruginosa) is one of the leading pathogens involved in nosocomial pneumonia. In addition, P. aeruginosa infection is associated with significant morbidity and mortality.1 A major problem in P. aeruginosa infection is that this organism exhibits natural and acquired resistance to many structurally and functionally diverse antibiotics.

  11. 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%.

  12. Binding of protegrin-1 to Pseudomonas aeruginosa and Burkholderia cepacia

    Directory of Open Access Journals (Sweden)

    Lehrer Robert I

    2002-03-01

    Full Text Available Abstract Background Pseudomonas aeruginosa and Burkholderia cepacia infections of cystic fibrosis patients' lungs are often resistant to conventional antibiotic therapy. Protegrins are antimicrobial peptides with potent activity against many bacteria, including P. aeruginosa. The present study evaluates the correlation between protegrin-1 (PG-1 sensitivity/resistance and protegrin binding in P. aeruginosa and B. cepacia. Methods The PG-1 sensitivity/resistance and PG-1 binding properties of P. aeruginosa and B. cepacia were assessed using radial diffusion assays, radioiodinated PG-1, and surface plasmon resonance (BiaCore. Results The six P. aeruginosa strains examined were very sensitive to PG-1, exhibiting minimal active concentrations from 0.0625–0.5 μg/ml in radial diffusion assays. In contrast, all five B. cepacia strains examined were greater than 10-fold to 100-fold more resistant, with minimal active concentrations ranging from 6–10 μg/ml. When incubated with a radioiodinated variant of PG-1, a sensitive P. aeruginosa strain bound considerably more protegrin molecules per cell than a resistant B. cepacia strain. Binding/diffusion and surface plasmon resonance assays revealed that isolated lipopolysaccharide (LPS and lipid A from the sensitive P. aeruginosa strains bound PG-1 more effectively than LPS and lipid A from resistant B. cepacia strains. Conclusion These findings support the hypothesis that the relative resistance of B. cepacia to protegrin is due to a reduced number of PG-1 binding sites on the lipid A moiety of its LPS.

  13. Biogenic silver and gold nanoparticles synthesized using red ginseng root extract, and their applications.

    Science.gov (United States)

    Singh, Priyanka; Kim, Yeon Ju; Wang, Chao; Mathiyalagan, Ramya; El-Agamy Farh, Mohamed; Yang, Deok Chun

    2016-05-01

    In the present study, we report a green methodology for the synthesis of silver and gold nanoparticles, using the root extract of the herbal medicinal plant Korean red ginseng. The silver and gold nanoparticles were synthesized within 1 h and 10 min respectively. The nanoparticles generated were not aggregated, and remained stable for a long time, which suggests the nature of nanoparticles. The phytochemicals and ginsenosides present in the root extract assist in reducing and stabilizing the synthesized nanoparticles. The red ginseng root extract-generated silver nanoparticles exhibit antimicrobial activity against pathogenic microorganisms including Vibrio parahaemolyticus, Staphylococcus aureus, Bacillus cereus, and Candida albicans. In addition, the silver nanoparticles exhibit biofilm degrading activity against S. aureus and Pseudomonas aeruginosa. Thus, the present study opens up a new possibility of synthesizing silver and gold nanoparticles in a green and rapid manner using Korean red ginseng root extract, and explores their biomedical applications. PMID:25706249

  14. Combined effects of graphene oxide and Cd on the photosynthetic capacity and survival of Microcystis aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yulin, E-mail: tangyulin@tongji.edu.cn; Tian, Jinglin; Li, Shuyan; Xue, Chonghua; Xue, Zhehua; Yin, Daqiang; Yu, Shuili

    2015-11-01

    In this work, the combined effects of graphene oxide (GO) and Cd{sup 2+} solution on Microcystis aeruginosa were investigated. Chlorophyll fluorescence parameters were measured by a pulse-amplitude modulated fluorometer. GO at low concentrations exhibited no significant toxicity. The presence of GO at low concentrations significantly enhanced Cd{sup 2+} toxicity as the 96 h half maximal effective concentration of the Cd{sup 2+} reduced from 0.51 ± 0.01 to 0.474 ± 0.01 mg/L. However, concentrations of GO above 5 mg/L did not significantly increase the toxicity of the Cd{sup 2+}/GO system. Observations through scanning and transmission electron microscopy revealed that GO, with Cd{sup 2+}, easily attached to and entered into the algae. Reactive oxygen species and malondialdehyde were measured to explain the toxicity mechanism. The photosynthetic parameters were useful in measuring the combined toxicity of the nanoparticles and heavy metals. - Highlights: • Combined effects of graphene oxide and Cd{sup 2+} to M. aeruginosa were investigated. • Chlorophyll fluorescence parameters were obtained by PAM. • OS and MDA were measured to evaluate algae toxicity. • GO at low concentration enhanced Cd{sup 2+} toxicity.

  15. Combined effects of graphene oxide and Cd on the photosynthetic capacity and survival of Microcystis aeruginosa

    International Nuclear Information System (INIS)

    In this work, the combined effects of graphene oxide (GO) and Cd2+ solution on Microcystis aeruginosa were investigated. Chlorophyll fluorescence parameters were measured by a pulse-amplitude modulated fluorometer. GO at low concentrations exhibited no significant toxicity. The presence of GO at low concentrations significantly enhanced Cd2+ toxicity as the 96 h half maximal effective concentration of the Cd2+ reduced from 0.51 ± 0.01 to 0.474 ± 0.01 mg/L. However, concentrations of GO above 5 mg/L did not significantly increase the toxicity of the Cd2+/GO system. Observations through scanning and transmission electron microscopy revealed that GO, with Cd2+, easily attached to and entered into the algae. Reactive oxygen species and malondialdehyde were measured to explain the toxicity mechanism. The photosynthetic parameters were useful in measuring the combined toxicity of the nanoparticles and heavy metals. - Highlights: • Combined effects of graphene oxide and Cd2+ to M. aeruginosa were investigated. • Chlorophyll fluorescence parameters were obtained by PAM. • OS and MDA were measured to evaluate algae toxicity. • GO at low concentration enhanced Cd2+ toxicity

  16. Characterization and bacterial toxicity of lanthanum oxide bulk and nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Brabu Balusamy; Yamuna Gowri Kandhasamy; Anitha Senthamizhan; Gopalakrishnan Chandrasekaran; Murugan Siva Subramanian; Kumaravel Tirukalikundram S

    2012-01-01

    This study evaluated the bacterial toxicity of lanthanum oxide micron and nano sized particles using shake flask method against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli,Pseudomonas aeruginosa) bacteria.Particle size,morphology and chemical composition were determined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS).Resuits indicated that lanthanum oxide nanoparticles showed antimicrobial activity against Staphylococcus aureus,but not against Escherichia coli and Pseudomonas aeruginosa.It was speculated that lanthanum oxide produced this effect by interacting with the gram-positive bacterial cell wall.Furthermore,lanthanum oxide bulk particles were found to enhance the pyocyanin pigment production in Pseudomonas aeruginosa.

  17. Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa (P. aeruginosa) biofilm

    Science.gov (United States)

    Argyraki, A.; Markvart, M.; Nielsen, Anne; Bjarnsholt, T.; Bjørndal, L.; Petersen, P. M.

    2016-04-01

    Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas aeruginosa (P. aeruginosa) is a common bacterium that can cause skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation, on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose was ramped from 72J/m2 to 10000J/m2. It was shown that UVB irradiation was more effective than UVC irradiation in inactivating P. aeruginosa biofilms. No colony forming units (CFU) were observed for the UVB treated biofilms when the dose was 10000 J/m2 (CFU in control sample: 7.5 x 104). UVB irradiation at a dose of 20000J/m2 on mature biofilms (72h grown) resulted in a 3.9 log killing efficacy. The fact that the wavelength of 296nm exists in daylight and has such disinfection ability on biofilms gives new perspectives for applications within disinfection at hospitals.

  18. Specific and selective electrochemical immunoassay for Pseudomonas aeruginosa based on pectin-gold nano composite.

    Science.gov (United States)

    Krithiga, N; Viswanath, K Balaji; Vasantha, V S; Jayachitra, A

    2016-05-15

    In this report, we have successfully fabricated an immunosensor for detection of Pseudomonas aeruginosa in water. The monoclonal antibody was immobilized on the surface modified with CCLP (Calcium Cross-Linked Pectin)-Au NPs (gold nanoparticles)/Glassy Carbon Electrode. The building of the immunosensor was evaluated in each step by cyclic voltammetry (CV) and impedance spectroscopy (EIS). The electrochemical detection was done based on the anti rabbit IgG HRP (Horseradish Peroxidase) which binds to the immune complex and the response was observed using Hydro Quininone (HQ) and Hydrogen peroxide (H2O2) in PB (Phosphate Buffer) electrolyte. From the results, the sensitivity range is from 10(1) to 10(7)CFU/ml and LOD is calculated as 9×10(2)CFU/ml. The developed immunosensor also have high selectivity, stability, reproducibility and reusability. PMID:26703990

  19. Endotoxin hitchhiking on polymer nanoparticles.

    Science.gov (United States)

    Donnell, Mason L; Lyon, Andrew J; Mormile, Melanie R; Barua, Sutapa

    2016-07-15

    The control of microbial infections is critical for the preparation of biological media including water to prevent lethal septic shock. Sepsis is one of the leading causes of death in the United States. More than half a million patients suffer from sepsis every year. Both gram-positive and gram-negative bacteria are responsible for septic infection by the most common organisms i.e., Escherichia coli and Pseuodomonas aeruginosa. The bacterial cell membrane releases negatively charged endotoxins upon death and enzymatic destruction, which stimulate antigenic response in humans to gram-negative infections. Several methods including distillation, ethylene oxide treatment, filtration and irradiation have been employed to remove endotoxins from contaminated samples, however, the reduction efficiency remains low, and presents a challenge. Polymer nanoparticles can be used to overcome the current inability to effectively sequester endotoxins from water. This process is termed endotoxin hitchhiking. The binding of endotoxin on polymer nanoparticles via electrostatic and hydrophobic interactions offers efficient removal from water. However, the effect of polymer nanoparticles and its surface areas has not been investigated for removal of endotoxins. Poly(ε-caprolactone) (PCL) polymer was tested for its ability to effectively bind and remove endotoxins from water. By employing a simple one-step phase separation technique, we were able to synthesize PCL nanoparticles of 398.3 ± 95.13 nm size and a polydispersity index of 0.2. PCL nanoparticles showed ∼78.8% endotoxin removal efficiency, the equivalent of 3.9 × 10(5) endotoxin units (EU) per ml. This is 8.34-fold more effective than that reported for commercially available membranes. Transmission electron microscopic images confirmed binding of multiple endotoxins to the nanoparticle surface. The concept of using nanoparticles may be applicable not only to eliminate gram-negative bacteria, but also for any gram

  20. Endotoxin hitchhiking on polymer nanoparticles

    Science.gov (United States)

    Donnell, Mason L.; Lyon, Andrew J.; Mormile, Melanie R.; Barua, Sutapa

    2016-07-01

    The control of microbial infections is critical for the preparation of biological media including water to prevent lethal septic shock. Sepsis is one of the leading causes of death in the United States. More than half a million patients suffer from sepsis every year. Both gram-positive and gram-negative bacteria are responsible for septic infection by the most common organisms i.e., Escherichia coli and Pseuodomonas aeruginosa. The bacterial cell membrane releases negatively charged endotoxins upon death and enzymatic destruction, which stimulate antigenic response in humans to gram-negative infections. Several methods including distillation, ethylene oxide treatment, filtration and irradiation have been employed to remove endotoxins from contaminated samples, however, the reduction efficiency remains low, and presents a challenge. Polymer nanoparticles can be used to overcome the current inability to effectively sequester endotoxins from water. This process is termed endotoxin hitchhiking. The binding of endotoxin on polymer nanoparticles via electrostatic and hydrophobic interactions offers efficient removal from water. However, the effect of polymer nanoparticles and its surface areas has not been investigated for removal of endotoxins. Poly(ε-caprolactone) (PCL) polymer was tested for its ability to effectively bind and remove endotoxins from water. By employing a simple one-step phase separation technique, we were able to synthesize PCL nanoparticles of 398.3 ± 95.13 nm size and a polydispersity index of 0.2. PCL nanoparticles showed ∼78.8% endotoxin removal efficiency, the equivalent of 3.9 × 105 endotoxin units (EU) per ml. This is 8.34-fold more effective than that reported for commercially available membranes. Transmission electron microscopic images confirmed binding of multiple endotoxins to the nanoparticle surface. The concept of using nanoparticles may be applicable not only to eliminate gram-negative bacteria, but also for any gram

  1. Potentiating effect of ecofriendly synthesis of copper oxide nanoparticles using brown alga: antimicrobial and anticancer activities

    Indian Academy of Sciences (India)

    SRI VISHNU PRIYA RAMASWAMY; S NARENDHRAN; RAJESHWARI SIVARAJ

    2016-04-01

    This study reports the in vitro antimicrobial and anticancer activities of biologically synthesized copper nanoparticles. The antimicrobial activity of green synthesized copper oxide nanoparticles was assessed by well diffusion method. The anticancer activity of brown algae-mediated copper oxide nanoparticles was determined by MTT assay against the cell line (MCF-7). Maximum activity was observed with Pseudomonas aeruginosa and Aspergillus niger. Effective growth inhibition of cells was observed to be more than 93% in antibacterial activity. Thus, the results of the present study indicates that biologically synthesized copper nanoparticles can be used for several diseases, however, it necessitates clinical studies to ascertain their potential as antimicrobial and anticancer agents.

  2. 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...... synthesis was restricted to a narrow band in the part of the biofilm adjacent to the source of oxygen. The zone of active GFP expression was approximately 60 Am wide in colony biofilms and 30 Am wide in flow cell biofilms. The region of the biofilm in which cells were capable of elongation was mapped by...... treating colony biofilms with carbenicillin, which blocks cell division, and then measuring individual cell lengths by transmission electron microscopy. Cell elongation was localized at the air interface of the biofilm. The heterogeneous anabolic patterns measured inside these biofilms were likely a result...

  3. Targeted nanoparticles for enhanced X-ray radiation killing of multidrug-resistant bacteria

    Science.gov (United States)

    Luo, Yang; Hossain, Mainul; Wang, Chaoming; Qiao, Yong; An, Jincui; Ma, Liyuan; Su, Ming

    2012-12-01

    This paper describes a nanoparticle enhanced X-ray irradiation based strategy that can be used to kill multidrug resistant (MDR) bacteria. In the proof-of-concept experiment using MDR Pseudomonas aeruginosa (P. aeruginosa) as an example, polyclonal antibody modified bismuth nanoparticles are introduced into bacterial culture to specifically target P. aeruginosa. After washing off uncombined bismuth nanoparticles, the bacteria are irradiated with X-rays, using a setup that mimics a deeply buried wound in humans. Results show that up to 90% of MDR P. aeruginosa are killed in the presence of 200 μg ml-1 bismuth nanoparticles, whereas only ~6% are killed in the absence of bismuth nanoparticles when exposed to 40 kVp X-rays for 10 min. The 200 μg ml-1 bismuth nanoparticles enhance localized X-ray dose by 35 times higher than the control with no nanoparticles. In addition, no significant harmful effects on human cells (HeLa and MG-63 cells) have been observed with 200 μg ml-1 bismuth nanoparticles and 10 min 40 kVp X-ray irradiation exposures, rendering the potential for future clinical use. Since X-rays can easily penetrate human tissues, this bactericidal strategy has the potential to be used in effectively killing deeply buried MDR bacteria in vivo.This paper describes a nanoparticle enhanced X-ray irradiation based strategy that can be used to kill multidrug resistant (MDR) bacteria. In the proof-of-concept experiment using MDR Pseudomonas aeruginosa (P. aeruginosa) as an example, polyclonal antibody modified bismuth nanoparticles are introduced into bacterial culture to specifically target P. aeruginosa. After washing off uncombined bismuth nanoparticles, the bacteria are irradiated with X-rays, using a setup that mimics a deeply buried wound in humans. Results show that up to 90% of MDR P. aeruginosa are killed in the presence of 200 μg ml-1 bismuth nanoparticles, whereas only ~6% are killed in the absence of bismuth nanoparticles when exposed to 40 kVp X

  4. 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. PMID:20580207

  5. 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...

  6. 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; McDevitt, Christopher A

    2014-11-01

    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 (MoO4 (2-)). 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

  7. Alginate overproduction affects Pseudomonas aeruginosa biofilm structure and function

    DEFF Research Database (Denmark)

    Hentzer, Morten; Teitzel, G.M.; Balzer, G.J.; Heydorn, Arne; Molin, Søren; Givskov, Michael Christian; Parsek, M.R.

    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......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...... abiotic surface. Biofilms formed by an alginate- overproducing strain exhibit a highly structured architecture and are significantly more resistant to the antibiotic tobramycin than a biofilm formed by an isogenic nonmucoid strain. These results suggest that an important consequence of the conversion to...... mucoidy is an altered biofilm architecture that shows increasing resistance to antimicrobial treatments....

  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 conferri

  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. 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...

  11. Synthesis, characterization, and antimicrobial properties of copper nanoparticles

    Science.gov (United States)

    Usman, Muhammad Sani; Zowalaty, Mohamed Ezzat El; Shameli, Kamyar; Zainuddin, Norhazlin; Salama, Mohamed; Ibrahim, Nor Azowa

    2013-01-01

    Copper nanoparticle synthesis has been gaining attention due to its availability. However, factors such as agglomeration and rapid oxidation have made it a difficult research area. In the present work, pure copper nanoparticles were prepared in the presence of a chitosan stabilizer through chemical means. The purity of the nanoparticles was authenticated using different characterization techniques, including ultraviolet visible spectroscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The antibacterial as well as antifungal activity of the nanoparticles were investigated using several microorganisms of interest, including methicillin-resistant Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella choleraesuis, and Candida albicans. The effect of a chitosan medium on growth of the microorganism was studied, and this was found to influence growth rate. The size of the copper nanoparticles obtained was in the range of 2–350 nm, depending on the concentration of the chitosan stabilizer. PMID:24293998

  12. Membrane-bound respiratory chain of Pseudomonas aeruginosa grown aerobically.

    OpenAIRE

    Matsushita, K; M. Yamada; Shinagawa, E; Adachi, O; Ameyama, M

    1980-01-01

    The electron transport chain of the gram-negative bacterium Pseudomonas aeruginosa, grown aerobically, contained a number of primary dehydrogenases and respiratory components (soluble flavin, bound flavin, coenzyme Q9, heme b, heme c, and cytochrome o) in membrane particles of the organism. Cytochrome o, about 50% of the b-type cytochrome, seemed to function as a terminal oxidase in the respiratory chain. The electron transport chain of P. aeruginosa grown aerobically was suggested to be line...

  13. Rhamnolipid stimulates uptake of hydrophobic compounds by Pseudomonas aeruginosa

    OpenAIRE

    Noordman, WH; Janssen, DB

    2002-01-01

    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 biosurfactants. The degradation of hexadecane by P. aeruginosa was stimulated only by the rhamnolipid biosurfactant produced by the same organism. This rhamnolipid did not stimulate the biodegradation of ...

  14. Rhamnolipid Stimulates Uptake of Hydrophobic Compounds by Pseudomonas aeruginosa

    OpenAIRE

    Noordman, Wouter H.; Janssen, Dick B.

    2002-01-01

    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 biosurfactants. The degradation of hexadecane by P. aeruginosa was stimulated only by the rhamnolipid biosurfactant produced by the same organism. This rhamnolipid did not stimulate the biodegradation of ...

  15. The use of bacteriophages for P. aeruginosa biofilm control

    OpenAIRE

    Pires, Diana; Sillankorva, Sanna; Azeredo, Joana

    2011-01-01

    Pseudomonas aeruginosa is a relevant opportunistic pathogen frequently associated with several nosocomial infections and, worryingly, this bacterium shows a low antibiotic susceptibility. One of its virulence factors is related with the ability to adhere to surfaces and also human epithelium and form virulent biofllms. This work describes the isolation and characterization of lytic phages capable to infect antibiotic resistant P. aeruginosa strains. It is also described herein the potential o...

  16. Multidrug-Resistant Pseudomonas aeruginosa: Risk Factors and Clinical Impact†

    OpenAIRE

    Aloush, Valerie; Navon-Venezia, Shiri; Seigman-Igra, Yardena; Cabili, Shaltiel; Carmeli, Yehuda

    2006-01-01

    Pseudomonas aeruginosa, a leading nosocomial pathogen, may become multidrug resistant (MDR). Its rate of occurrence, the individual risk factors among affected patients, and the clinical impact of infection are undetermined. We conducted an epidemiologic evaluation and molecular typing using pulsed-field gel electrophoresis (PFGE) of 36 isolates for 82 patients with MDR P. aeruginosa and 82 controls matched by ward, length of hospital stay, and calendar time. A matched case-control study iden...

  17. Serum antibodies to Pseudomonas aeruginosa in cystic fibrosis.

    OpenAIRE

    Brett, M M; Ghoneim, A T; Littlewood, J M

    1986-01-01

    Serum IgG antibodies to Pseudomonas aeruginosa cell surface antigens were determined by enzyme linked immunosorbent assay. Titres in patients without cystic fibrosis were low (140-235). Those in patients with cystic fibrosis who were chronically infected by P. aeruginosa were very high (1100-20,500), while patients who grew the organism intermittently had lower titres (160-4400). Longitudinal studies showed that raised titres were observed at a very early stage of infection. High titres were ...

  18. Suppression of fungal growth exhibited by Pseudomonas aeruginosa.

    OpenAIRE

    Kerr, J. R.

    1994-01-01

    Three surgery patients were monitored postoperatively, with particular reference to lung infection. In each case there was a clinical impression that Pseudomonas aeruginosa suppressed the growth of Candida albicans in patients with clinically significant lung infections from whom both of these organisms were isolated from serial sputum samples. Regrowth of C. albicans after P. aeruginosa eradication occurred in two patients, despite fluconazole therapy, to which both C. albicans isolates were...

  19. Isolation of lytic phages for clinical antibiotic resistant Pseudomonas aeruginosa

    OpenAIRE

    Pires, Diana; Sillankorva, Sanna; Faustino, A.; Azeredo, Joana

    2009-01-01

    Pseudomonas aeruginosa is a relevant opportunist pathogen involved in noso-comial infections. P. aeruginosa uses an arsenal of virulence factors to cause serious infections and one of the most worrying characteristics of this bacte-rium is its low antibiotic susceptibility. The low susceptibility to antibiotics can be attributed to a concerted action of multidrug efflux pumps with chromo-somally-encoded antibiotic resistance genes and the low permeability of the bacterial cellular envelopes. ...

  20. Pseudomonas aeruginosa bacteremia secondary to acute right leg cellulitis

    OpenAIRE

    Abdul Wahab, Asrul; Rahman, M.M.

    2013-01-01

    Pseudomonas aeruginosa is a gram-negative bacillus that causes wide spectrum clinical infections. However, it is most frequently associated with hospital-acquired infection. In this case a 58-year-old male with underlying hypertension and dyslipidaemia was admitted for acute right leg cellulitis. Pseudomonas aeruginosa was identified from the case, though it was not a usual suspected organism. It might be due to community-acquired infection.

  1. Resistant patterns of Pseudomonas aeruginosa in a Malaysian teaching hospital

    Institute of Scientific and Technical Information of China (English)

    Zaidah AR; Siti SMN; Zahiruddin WM; Zeehaida M

    2009-01-01

    Objective:Pseudomonas aeruginosa is an opportunistic pathogen and the leading cause of nosocomial infec-tions.Currently a notable increase in the prevalence of multidrug-resistant P.aeruginosa worldwide has been reported in hospitalized patients and was associated with high morbidity and mortality.Methods:A retrospec-tive laboratory based analysis regarding the spectrum and distribution of P.aeruginosa from a wide range of clinical samples in Hospital Universiti Sains Malaysia since January 2003 to December 2007 was done.Re-sults:Altogether,there were 2 308 clinical isolates analyzed.The main sources of P.aeruginosa were from swab,respiratory,urine and blood specimens which accounted for 28.2 %,21.8 %,13.2 % and 12.8 %respectively.Results showed significant reduction in percentage of resistant towards three antibiotic namely ciprofloxacin,ceftazidime and imipenem.However the percentage of pan-resistant P.aeruginosa increased steadily over these years.Conclusion:This data is helpful to the clinician in guiding the choice of appropriate antibiotic to treat P.aeruginosa infection.At the same time,it warrants a more aggressive infection control ac-tivity to be implemented to control the spread of pan resistant strain in this centre.

  2. Effect of Pseudomonas aeruginosa Pure Exotoxin A on Mice WBC in Comparison with Human WBC Contaminated by Pseudomonas aeruginosa

    OpenAIRE

    M Naghmachi; A Sharifi; J Kohanteb

    2008-01-01

    ABSTRACT Introduction & Objective: Pseudomonas aeruginosa is a gram negative bacterial. This bacterium is resistant to many antibiotics and chemical disinfectants. Pseudomonas aeruginosa is an opportunistic bacteria and caused infection in skin, external ear, upper respiratory tract, large intestine and is an important bacteria in nosocomial infections. It causes acute infection in burn disease. This bacterium can produce exotoxin A and effect on elongation factor II and can stop protein ...

  3. Antibacterial potential of silver nanoparticles against isolated urinary tract infectious bacterial pathogens

    Science.gov (United States)

    Jacob Inbaneson, Samuel; Ravikumar, Sundaram; Manikandan, Nachiappan

    2011-12-01

    The silver nanoparticles were synthesized by chemical reduction method and the nanoparticles were characterized using ultraviolet-visible (UV-Vis) absorption spectroscopy and X-ray diffraction (XRD) studies. The synthesized silver nanoparticles were investigated to evaluate the antibacterial activity against urinary tract infectious (UTIs) bacterial pathogens. Thirty-two bacteria were isolated from mid urine samples of 25 male and 25 female patients from Thondi, Ramanathapuram District, Tamil Nadu, India and identified by conventional methods. Escherichia coli was predominant (47%) followed by Pseudomonas aeruginosa (22%), Klebsiella pneumoniae (19%), Enterobacter sp. (6%), Proteus morganii (3%) and Staphylococcus aureus (3%). The antibacterial activity of silver nanoparticles was evaluated by disc diffusion assay. P. aeruginosa showed maximum sensitivity (11 ± 0.58 mm) followed by Enterobacter sp. (8 ± 0.49 mm) at a concentration of 20 μg disc-1 and the sensitivity was highly comparable with the positive control kanamycin and tetracycline. K. pneumoniae, E. coli, P. morganii and S. aureus showed no sensitivity against all the tested concentrations of silver nanoparticles. The results provided evidence that, the silver nanoparticles might indeed be the potential sources to treat urinary tract infections caused by P. aeruginosa and Enterobacter sp.

  4. Adherence of Pseudomonas aeruginosa to contact lenses

    International Nuclear Information System (INIS)

    The purpose of this research was to examined the interactions of P. aeruginosa with hydrogel contact lenses and other substrata, and characterize adherence to lenses under various physiological and physicochemical conditions. Isolates adhered to polystyrene, glass, and hydrogel lenses. With certain lens types, radiolabeled cells showed decreased adherence with increasing water content of the lenses, however, this correlation with not found for all lenses. Adherence to rigid gas permeable lenses was markedly greater than adherence to hydrogels. Best adherence occurred near pH 7 and at a sodium chloride concentration of 50 mM. Passive adhesion of heat-killed cells to hydrogels was lower than the adherence obtained of viable cells. Adherence to hydrogels was enhanced by mucin, lactoferrin, lysozyme, IgA, bovine serum albumin, and a mixture of these macromolecules. Adherence to coated and uncoated lenses was greater with a daily-wear hydrogel when compared with an extended-wear hydrogel of similar polymer composition. Greater adherence was attributed to a higher concentration of adsorbed macromolecules on the 45% water-content lens in comparison to the 55% water-content lens

  5. 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.

  6. 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.

  7. The Genomic Basis of Evolutionary Innovation in Pseudomonas aeruginosa

    Science.gov (United States)

    Wagner, Andreas; MacLean, R. Craig

    2016-01-01

    Novel traits play a key role in evolution, but their origins remain poorly understood. Here we address this problem by using experimental evolution to study bacterial innovation in real time. We allowed 380 populations of Pseudomonas aeruginosa to adapt to 95 different carbon sources that challenged bacteria with either evolving novel metabolic traits or optimizing existing traits. Whole genome sequencing of more than 80 clones revealed profound differences in the genetic basis of innovation and optimization. Innovation was associated with the rapid acquisition of mutations in genes involved in transcription and metabolism. Mutations in pre-existing duplicate genes in the P. aeruginosa genome were common during innovation, but not optimization. These duplicate genes may have been acquired by P. aeruginosa due to either spontaneous gene amplification or horizontal gene transfer. High throughput phenotype assays revealed that novelty was associated with increased pleiotropic costs that are likely to constrain innovation. However, mutations in duplicate genes with close homologs in the P. aeruginosa genome were associated with low pleiotropic costs compared to mutations in duplicate genes with distant homologs in the P. aeruginosa genome, suggesting that functional redundancy between duplicates facilitates innovation by buffering pleiotropic costs. PMID:27149698

  8. Detection and characterization of metallo beta lactamases producing Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Manoharan A

    2010-01-01

    Full Text Available This study was undertaken to evaluate phenotypic and genotypic methods for detection of Metallo-Beta-Lactamases (MBLs among nosocomial Pseudomonas aeruginosa. Sixty one among 176 P. aeruginosa isolates, collected as part of a multicentric study (2005-2007, were evaluated for carbapenem resistance (CARB-R; resistant to either imipenem/meropenem and screened for MBL by Combination Disk Diffusion Test (CDDT using imipenem (IMP, meropenem (MER and ceftazidime (CAZ with EDTA. MBL positives were further confirmed by IMP + EDTA Etest. Twenty strains (42.6% were found to be MBL producers among the 61 P. aeruginosa. PCR for IMP and VIM MBL was performed on 48 of the 61, 15 were positive for VIM MBL type. CDDT using IMP + EDTA had the highest sensitivity and specificity of 87.8% and 84.4% when compared to Etest, which was higher than the values obtained for CAZ + EDTA and MER + EDTA. CDDT using IMP + EDTA also compared very well with the PCR (specificity = 90.9%, sensitivity = 93.3%. CARB-R among P. aeruginosa is mediated predominantly via MBL production. Clinical P. aeruginosa isolates can be screened routinely using the less expensive IMP + EDTA CDDT in clinical microbiology laboratories.

  9. METALLO-BETA-LACTAMASE PRODUCING PSEUDOMONAS AERUGINOSA IN NEONATAL SEPTICEMIA

    Directory of Open Access Journals (Sweden)

    Murthy

    2014-05-01

    Full Text Available The emergence, selective multiplication & dissemination of antibacterial resistance is a serious global problem. This study was conducted with the objective to examine the incidence of metallo-beta-lactamase (MβL producing strains among multidrug resistant (MDR Pseudomonas aeruginosa from the suspected cases of neonatal sepsis between January 2011 – December 2013. A total of 994 cases admitted with the suspicion of neonatal sepsis were investigated. 295 (29.7% isolates were obtained from the blood cultures of neonates. The isolates were identified and tested for the susceptibility to various antimicrobial agents. Pseudomonas aeruginosa with 116 (48.3% isolation among 240 Gram negative isolates, was the predominant pathogen in our study. All the 74 (63.8% multidrug resistant P. aeruginosa isolates were screened initially for Imipenem resistance, which were further tested for the presence of MβL by Imipenem-ethylene diamine tetraacetic acid (EDTA disc method. MβL production was seen in 20 (71.4% of the 28 Imipenem-resistant Pseudomonas aeruginosa isolates. MβL producing Pseudomonas aeruginosa has emerged as a potential threat in cases of neonatal septicemia and poses great therapeutic challenge for physicians treating such infections.

  10. The Genomic Basis of Evolutionary Innovation in Pseudomonas aeruginosa.

    Science.gov (United States)

    Toll-Riera, Macarena; San Millan, Alvaro; Wagner, Andreas; MacLean, R Craig

    2016-05-01

    Novel traits play a key role in evolution, but their origins remain poorly understood. Here we address this problem by using experimental evolution to study bacterial innovation in real time. We allowed 380 populations of Pseudomonas aeruginosa to adapt to 95 different carbon sources that challenged bacteria with either evolving novel metabolic traits or optimizing existing traits. Whole genome sequencing of more than 80 clones revealed profound differences in the genetic basis of innovation and optimization. Innovation was associated with the rapid acquisition of mutations in genes involved in transcription and metabolism. Mutations in pre-existing duplicate genes in the P. aeruginosa genome were common during innovation, but not optimization. These duplicate genes may have been acquired by P. aeruginosa due to either spontaneous gene amplification or horizontal gene transfer. High throughput phenotype assays revealed that novelty was associated with increased pleiotropic costs that are likely to constrain innovation. However, mutations in duplicate genes with close homologs in the P. aeruginosa genome were associated with low pleiotropic costs compared to mutations in duplicate genes with distant homologs in the P. aeruginosa genome, suggesting that functional redundancy between duplicates facilitates innovation by buffering pleiotropic costs. PMID:27149698

  11. 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.

  12. Cystic fibrosis-niche adaptation of Pseudomonas aeruginosa reduces virulence in multiple infection hosts

    OpenAIRE

    Lorè, Nicola Ivan; Cigana, Cristina; De Fino, Ida; Riva, Camilla; Juhas, Mario; Schwager, Stephan; Eberl, Leo; Bragonzi, Alessandra

    2012-01-01

    The opportunistic pathogen Pseudomonas aeruginosa is able to thrive in diverse ecological niches and to cause serious human infection. P. aeruginosa environmental strains are producing various virulence factors that are required for establishing acute infections in several host organisms; however, the P. aeruginosa phenotypic variants favour long-term persistence in the cystic fibrosis (CF) airways. Whether P. aeruginosa strains, which have adapted to the CF-niche, have lost their competitive...

  13. Phenolic compounds affect production of pyocyanin, swarming motility and biofilm formation of Pseudomonas aeruginosa

    OpenAIRE

    Aylin Ugurlu; Aysegul Karahasan Yagci; Seyhan Ulusoy; Burak Aksu; Gulgun Bosgelmez-Tinaz

    2016-01-01

    Objective: To investigate the effects of plant-derived phenolic compounds (i.e. caffeic acid, cinnamic acid, ferulic acid and vanillic acid) on the production of quorum sensing regulated virulence factors such as pyocyanin, biofilm formation and swarming motility of Pseudomonas aeruginosa (P. aeruginosa) isolates. Methods: Fourteen clinical P. aeruginosa isolates obtained from urine samples and P. aeruginosa PA01 strain were included in the study. The antibacterial effects of phenolic comp...

  14. Hydrophobicity of biofilm coatings influences the transport dynamics of polystyrene nanoparticles in biofilm-coated sand.

    Science.gov (United States)

    Mitzel, Michael R; Sand, Stefanie; Whalen, Joann K; Tufenkji, Nathalie

    2016-04-01

    Engineered nanoparticles (ENPs) are used in the manufacture of over 2000 industrial and consumer products to enhance their material properties and functions or to enable new nanoparticle-dependent functions. The widespread use of ENPs will result in their release to the subsurface and aquatic environments, where they will interact with indigenous biota. Laboratory column experiments were designed to understand the influence of two different Pseudomonas aeruginosa biofilms on the mobility of polystyrene latex nanoparticles in granular porous media representative of groundwater aquifers or riverbank filtration settings. The transport behavior of 20 nm carboxylate-modified (CLPs) and sulfate (SLPs) polystyrene latex ENPs suspended in NaCl or CaCl2 (1 and 10 mM ionic strength, pH 7) was studied in columns packed with quartz sand coated with biofilms formed by two P. aeruginosa strains that differed in cell surface hydrophobicity (P. aeruginosa 9027™, relatively hydrophilic and P. aeruginosa PAO1, relatively hydrophobic). Biofilm-coated quartz sand retained more of the electrostatically-stabilized latex ENPs than clean, uncoated sand, regardless of the serotype. As IS increased, clear differences in the shape of the ENP breakthrough curves were observed for each type of biofilm coating. ENP breakthrough in the P. aeruginosa PAO1 biofilm-coated sand was generally constant with time whereby breakthrough in the P. aeruginosa 9027 biofilm-coated sand showed dynamic behavior. This indicates a fundamental difference in the mechanisms of ENP deposition onto hydrophilic or hydrophobic biofilm coatings due to the hydration properties of these biofilms. The results of this study demonstrate the importance of considering the surface properties of aquifer grain coatings when evaluating ENP fate in natural subsurface environments. PMID:26845456

  15. Antibacterial activity of poly(vinyl alcohol)-b-poly(acrylonitrile) based micelles loaded with silver nanoparticles.

    Science.gov (United States)

    Bryaskova, Rayna; Pencheva, Daniela; Kyulavska, Mariya; Bozukova, Dimitriya; Debuigne, Antoine; Detrembleur, Christophe

    2010-04-15

    A new amphiphilic poly(vinyl alcohol)-b-poly(acrylonitrile) (PVOH-b-PAN) copolymer obtained by selective hydrolysis of well-defined poly(vinyl acetate)-b-poly(acrylonitrile) copolymer synthesized by cobalt mediated radical polymerization was used for the preparation of PVOH-b-PAN based micelles with embedded silver nanoparticles. The successful formation of silver loaded micelles has been confirmed by UV-vis, DLS and TEM analysis and their antibacterial activity against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa) and spore solution of Bacillus subtilis (B. subtilis) has been studied. PVOH-b-PAN based micelles with embedded silver nanoparticles showed a strong bactericidal effect against E. coli, S. aureus and P. aeruginosa and the minimum bactericidal concentration for each system (MBC) has been determined. PMID:20074742

  16. 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.

  17. 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. PMID:27102839

  18. Sphingoid long chain bases prevent lung infection by Pseudomonas aeruginosa

    Science.gov (United States)

    Pewzner-Jung, Yael; Tavakoli Tabazavareh, Shaghayegh; Grassmé, Heike; Becker, Katrin Anne; Japtok, Lukasz; Steinmann, Jörg; Joseph, Tammar; Lang, Stephan; Tuemmler, Burkhard; Schuchman, Edward H; Lentsch, Alex B; Kleuser, Burkhard; Edwards, Michael J; Futerman, Anthony H; Gulbins, Erich

    2014-01-01

    Cystic fibrosis patients and patients with chronic obstructive pulmonary disease, trauma, burn wound, or patients requiring ventilation are susceptible to severe pulmonary infection by Pseudomonas aeruginosa. Physiological innate defense mechanisms against this pathogen, and their alterations in lung diseases, are for the most part unknown. We now demonstrate a role for the sphingoid long chain base, sphingosine, in determining susceptibility to lung infection by P. aeruginosa. Tracheal and bronchial sphingosine levels were significantly reduced in tissues from cystic fibrosis patients and from cystic fibrosis mouse models due to reduced activity of acid ceramidase, which generates sphingosine from ceramide. Inhalation of mice with sphingosine, with a sphingosine analog, FTY720, or with acid ceramidase rescued susceptible mice from infection. Our data suggest that luminal sphingosine in tracheal and bronchial epithelial cells prevents pulmonary P. aeruginosa infection in normal individuals, paving the way for novel therapeutic paradigms based on inhalation of acid ceramidase or of sphingoid long chain bases in lung infection. PMID:25085879

  19. 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, we...... 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......-deficient P. aeruginosa quorum-sensing mutant are more susceptible to aminoglycoside treatment than wild-type biofilms but become rescued from the detrimental action of aminoglycosides upon supplementation with exogenous DNA. Furthermore, we demonstrate that exposure to lysed polymorphonuclear leukocytes...

  20. Effects of antibiotics on quorum sensing in pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Skindersø, Mette Elena; Alhede, Morten; Phipps, Richard Kerry;

    2008-01-01

    impeding QS, thereby reducing the pathogenicity of P. aeruginosa. This led us to investigate whether QS inhibition is a common feature of antibiotics. We present the results of a screening of 12 antibiotics for their QS-inhibitory activities using a previously described QS inhibitor selector 1 strain...... animal infection models. Treatment of cystic fibrosis (CF) patients chronically infected with P. aeruginosa with the macrolide antibiotic azithromycin (AZM) has been demonstrated to improve the clinical outcome. Several studies indicate that AZM may accomplish its beneficial action in CF patients by....... Three of the antibiotics tested, AZM, ceftazidime (CFT), and ciprofloxacin (CPR), were very active in the assay and were further examined for their effects on QS-regulated virulence factor production in P. aeruginosa. The effects of the three antibiotics administered at subinhibitory concentrations were...

  1. Subtilase SprP exerts pleiotropic effects in Pseudomonas aeruginosa.

    Science.gov (United States)

    Pelzer, Alexander; Polen, Tino; Funken, Horst; Rosenau, Frank; Wilhelm, Susanne; Bott, Michael; Jaeger, Karl-Erich

    2014-02-01

    The open reading frame PA1242 in the genome of Pseudomonas aeruginosa PAO1 encodes a putative protease belonging to the peptidase S8 family of subtilases. The respective enzyme termed SprP consists of an N-terminal signal peptide and a so-called S8 domain linked by a domain of unknown function (DUF). Presumably, this DUF domain defines a discrete class of Pseudomonas proteins as homologous domains can be identified almost exclusively in proteins of the genus Pseudomonas. The sprP gene was expressed in Escherichia coli and proteolytic activity was demonstrated. A P. aeruginosa ∆sprP mutant was constructed and its gene expression pattern compared to the wild-type strain by genome microarray analysis revealing altered expression levels of 218 genes. Apparently, SprP is involved in regulation of a variety of different cellular processes in P. aeruginosa including pyoverdine synthesis, denitrification, the formation of cell aggregates, and of biofilms. PMID:24376018

  2. Synergic interaction between ascorbic acid and antibiotics against Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Luciana Cursino

    2005-05-01

    Full Text Available Studies were carried out on in vitro combination of ascorbic acid (AA with six antibiotics against 12 multi-resistant Pseudomonas aeruginosa isolates. Synergic activity was detected with AA chloramphenicol, kanamycin, streptomycin and tetracycline. Indifference was observed to any antibiotics and antagonism only for chloramphenicol. Results indicated that multiresistant P. aeruginosa was affected by combination of AA and antibiotics. Future research on ascorbic acid-antimicrobial interactions may find new methods to control strains of multiresistant P. aeruginosa.Investigou-se in vitro o efeito da combinação do ácido ascórbico (AA com seis antibióticos frente a 12 isolados multirresistentes de Pseudomonas aeruginosa. As concentrações inibitórias mínimas (CIM foram determinadas pelo método de diluição em caldo. Foi estudado o efeito do AA nas CIM pelo cálculo das concentrações inibitórias fracionais (CIF. Para quase todas as combinações AA-antibiótico foi detectado efeito sinérgico, exceto para ampicilina e tobramicina. Indiferença foi observada na interação com todos os antibióticos, porém antagonismo foi somente observado para cloranfenicol. Os resultados deste estudo indicam que o sinergismo contra P. aeruginosa resistentes pode ocorrer entre AA e cloranfenicol, canamicina, estreptomicina e tetraciclina, ainda que as linhagens sejam resistentes aos antibióticos individualmente. Além disso, estes resultados encorajam futuros trabalhos in vivo a respeito da interação AA-antimicrobianos na incessante busca de novas alternativas para o controle de linhagens multirresistentes de P.aeruginosa.

  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 chemosensory proteins for trichloroethylene in Pseudomonas aeruginosa

    OpenAIRE

    Shitashiro, Maiko; Tanaka, Hirohide; Hong, Chang Soo; Kuroda, Akio; Takiguchi, Noboru; Ohtake, Hisao; Kato, Junichi

    2005-01-01

    The involvement of the chemotaxis gene cluster 1 (cheYZABW) and cheR in repellent responses of Pseudomonas aeruginosa to trichloroethylene (TCE) is described and three methyl-accepting chemotaxis proteins (MCPs) for TCE are identified. TCE chemotaxis assays of a number of deletion-insertion mutants of P. aeruginosa PAO1 revealed that the chemotaxis gene cluster 1 and cheR are required for negative chemotaxis to TCE. Mutant strains which contained deletions in pctA, pctB and pctC showed decrea...

  5. Bioleaching of copper oxide ore by Pseudomonas aeruginosa

    Science.gov (United States)

    Shabani, M. A.; Irannajad, M.; Azadmehr, A. R.; Meshkini, M.

    2013-12-01

    Bioleaching is an environmentally friendly method for extraction of metal from ores. In this study, bioleaching of copper oxide ore by Pseudomonas aeruginosa was investigated. Pseudomonas aeruginosa is a heterotrophic bacterium that can produce various organic acids in an appropriate culture medium, and these acids can operate as leaching agents. The parameters, such as particle size, glucose percentage in the culture medium, bioleaching time, and solid/liquid ratio were optimized. Optimum bioleaching conditions were found as follows: particle size of 150-177 μm, glucose percentage of 6%, bioleaching time of 8 d, and solid/liquid ratio of 1:80. Under these conditions, 53% of copper was extracted.

  6. Ultraviolet-B lethal damage on Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Pseudomonas aeruginosa has shown an increased sensitivity compared with that of Escherichia coli and Enterobacter cloacae, when they were exposed to 0.4 kJ/m2 of ultraviolet-B radiation. The rapid decay in cell viability observed in Pseudomonas aeruginosa after the irradiation was influenced by factors such as culture media and the presence of pyocyanine during the irradiation. The radioinduced lethal damage could be prevented by photoreactivating treatment, indicating that pyrimidine dimer formation was the mechanism causing bacterial death. The results indicate that several environmental conditions may act as protective agents against ultraviolet-B-induced damage

  7. [Structural components and peculiarities of Pseudomonas aeruginosa biofilm organization].

    Science.gov (United States)

    Balko, O B; Avdieieva, L V

    2010-01-01

    Peculiarities of the structural organization of bacterial biofilm during its formation and disintegration have been investigated on the model of Pseudomonas aeruginosa UCM B-900 (ATCC 9027). It was shown, that development of the biofilm in a stationary system on glass was a two-vector process with changes in time and space. P. aeruginosa UCM B-900 biofilm is formed from single cells, passes through the stages of base components, net structure, islands and comes to the end with integration into a complete monolayer. The biofilm degradation repeats the stages of its formation in the reverse sequence. PMID:20812507

  8. Reduction of PCN biosynthesis by NO in Pseudomonas aeruginosa

    OpenAIRE

    Lei Gao; Yuying Zhang; Yan Wang; Xinhua Qiao; Jing Zi; Chang Chen; Yi Wan

    2016-01-01

    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 w...

  9. Biosynthesis, characterization and antimicrobial action of silver nanoparticles from root bark extract of Berberislycium Royle.

    Science.gov (United States)

    Mehmood, Ansar; Murtaza, Ghulam; Bhatti, Tariq Mahmood; Kausar, Rehana; Ahmed, Muhammad Jamil

    2016-01-01

    Various biological methods are being recognized for the fabrication of silver nanoparticles, which are used in several fields. The phytosynthesis of nanoparticles came out as a cost effective and enviro-friendly approach. When root bark extract of Berberis lycium was treated with silver ions, they reduced to silver nanoparticles, which were spherical, crystalline, size ranged from 10-100nm and capped by biomolecules. Synthesized silver nanoparticles were characterized by UV-visible spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) and Fourier Transform Infra Red Spectroscopy (FTIR). The plant mediated synthesized silver nanoparticles showed pronounced antimicrobial activities against both Gram negative bacteria (Escherichia coli, Klebseilla pneumoniae, Pseudomonas aeruginosa) and Gram positive bacteria (Staphylococcus aureus and Bacillus subtilis). The plant mediated process proved to be non-toxic and low cost contender as reducing agent for synthesizing stable silver nanoparticles. PMID:26826826

  10. Antibacterial Properties of Copper Nanoparticle Dispersions: Influence of Synthesis Conditions and Physicochemical Characteristics

    Science.gov (United States)

    Godymchuk, A.; Frolov, G.; Gusev, A.; Zakharova, O.; Yunda, E.; Kuznetsov, D.; Kolesnikov, E.

    2015-11-01

    The production of bactericidal plasters, bandages and medicines with the inclusion of copper nanoparticles and copper ions may have a great potential in terms of their biomedical application. The work considers the influence of the synthesis conditions, size, aggregation status, and charge of nanoparticles in aqueous solutions as well as the type of microorganisms to the antibacterial properties of water suspensions of electroexplosive copper nanoparticles in the conditions in vitro in relation to strains Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus cereus. Water dispersions of copper nanoparticles were shown to inhibit the growth of test cells for both G+ and G- microbacteria but the degree of such an influence strongly depended on the type of a test strain. The authors have demonstrated that use of deeply purified water and alcohol-containing stabilizers at the synthesis of nanoparticles via metals electric erosion in the liquid prevents the copper nanoparticles coagulation and significantly influences on their physicochemical characteristics and, consequently, antibacterial properties.

  11. 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

    biofilms. Methods. P. aeruginosa biofilms were generated in vitro and in rat lungs. In a pilot study, 5 patients with cystic fibrosis inhaled colistin and then tobramycin for 4 weeks. The changes in P. aeruginosa counts and lung function were assessed before and after therapy. Results. Antibiotic...... combination therapy significantly reduced the number of P. aeruginosa cells in P. aeruginosa biofilm models in vitro. When rats were challenged with 1 x 10(7) cfu of P. aeruginosa, which was embedded in alginate beads, mortality rates, lung pathologic findings, and bacterial colony-forming unit counts were...

  12. Superior bactericidal activity of SDS capped silver nanoparticles: Synthesis and characterization

    International Nuclear Information System (INIS)

    Silver nanoparticles were synthesized through UV photo-reduction of silver nitrate aqueous solution, containing ethanol and sodium dodecyl sulfate (SDS) using an UV digester equipped with high pressure mercury lamp of 500 W. The synthesized nanoparticles were characterized by UV-vis spectroscopy (UV-vis), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The formation of silver nanoparticles was confirmed from the appearance of surface plasmon absorption maxima at 418 nm. TEM showed the spherical nanoparticles with size in 23-67 nm (average 45 ± 10 nm). The silver nanoparticles were stable for more than 8 months. The antibacterial activity of these SDS capped silver nanoparticles was tested using Pseudomonas aeruginosa as a model strain for gram-negative bacteria. SDS capped silver nanoparticles exhibit a much higher bactericidal activity compared to silver nanoparticles capped with other capping agents. Even at a low silver nanoparticle concentration of 5 μg/ml, complete inhibition of 107 colony forming units (CFU) was achieved with SDS capped silver nanoparticles. This concentration is much lower than the values reported by other authors. This enhanced bactericidal activity is attributed to much efficient transport of silver nanoparticles by SDS to the outer membrane of cell wall compared to the other capping agents and have a better interaction of nanoparticles with the cell.

  13. Synthesis, characterization and evaluation of silver nanoparticles through leaves of Abrus precatorius L.: an important medicinal plant

    Science.gov (United States)

    Gaddala, Bhumi; Nataru, Savithramma

    2015-01-01

    Biologically synthesized nanoparticles have been widely used in the field of medicine. The present study reports the green synthesis of silver nanoparticles using Abrus precatorius leaf extract with silver nitrate solution as reducing agent. The synthesized silver nanoparticles were analyzed through UV-Visible spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, atomic force microscopy and Fourier transform infrared. The synthesized silver nanoparticles were disk shaped with an average size of 19 nm. These silver nanoparticles were evaluated for antibacterial activity. The diameter of inhibition zones around the disk of Pseudomonas aeruginosa and Staphylococcus aureus are resistant to silver nanoparticles, whereas Escherichia coli and Bacillus thuringiensis are susceptible when compared with the other two species. The results were compared with the ciprofloxacin-positive control and silver nitrate. It is concluded that the green synthesis of silver nanoparticles is very fast, easy, cost-effective and eco-friendly and without any side effects.

  14. 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

  15. Reduction of PCN biosynthesis by NO in Pseudomonas aeruginosa.

    Science.gov (United States)

    Gao, Lei; Zhang, Yuying; Wang, Yan; Qiao, Xinhua; Zi, Jing; Chen, Chang; Wan, Yi

    2016-08-01

    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 60μM 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. PMID:26874276

  16. Zingerone silences quorum sensing and attenuates virulence of Pseudomonas aeruginosa.

    Science.gov (United States)

    Kumar, Lokender; Chhibber, Sanjay; Kumar, Rajnish; Kumar, Manoj; Harjai, Kusum

    2015-04-01

    Quorum sensing in Pseudomonas aeruginosa plays an imperative role in virulence factor, biofilm formation and antimicrobial resistance. Blocking quorum sensing pathways are viewed as viable anti-virulent therapy in association with traditional antimicrobial therapy. Anti-quorum sensing dietary phytochemicals with may prove to be a safe and viable choice as anti-virulent drug candidates. Previously, our lab proved zingerone as potent anti-biofilm agent hence; further its anti-virulent and anti-quorum activities were evaluated. Zingerone, besides decreasing swimming, swarming and twitching phenotypes of P. aeruginosa PAO1, reduced biofilm forming capacity and production of virulence factors including rhamnolipid, elastase, protease, pyocyanin, cell free and cell bound hemolysin (pproduction of quorum sensing signal molecules by clinical isolates of P. aeruginosa but also showed significant interference with the activation of QS reporter strains. To study the mechanism of blocking quorum sensing cascade, in silico analysis was carried out. Anti-QS activity was attributed to interference with the ligand receptor interaction of zingerone with QS receptors (TraR, LasR, RhlR and PqsR). Zingerone showed a good comparative docking score to respective autoinducer molecules which was even higher than that of vanillin, a proven anti-quorum sensing phytochemical. The results of the present study revealed the anti-quorum sensing activity of zingerone targeting ligand-receptor interaction, hence proposing zingerone as a suitable anti-virulent drug candidate against P. aeruginosa infections. PMID:25704369

  17. 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....

  18. Pseudomonas aeruginosa host-adaptation in cystic fibrosis patients

    DEFF Research Database (Denmark)

    Rau, Martin Holm

    Pseudomonas aeruginosa is an opportunistic pathogen capable of transition from an environmental lifestyle to a host-associated lifestyle, as exemplified in the life-long airway infection of cystic fibrosis (CF) patients. Long-term infection is associated with extensive genetic adaptation of P...

  19. 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.

  20. Genetic characterization of Microcystis aeruginosa isolates from Portuguese freshwater systems.

    Science.gov (United States)

    Moreira, Cristiana; Vasconcelos, Vitor; Antunes, Agostinho

    2016-07-01

    Cyanobacteria are microorganisms that pose a serious threat to the aquatic waterways through the production of dense blooms under eutrophic conditions and the release of toxic secondary metabolites-cyanotoxins. Within cyanobacteria, the colonial planktonic Microcystis aeruginosa is widely distributed in both fresh and brackish aquatic environments throughout the world being frequently observed in the Portuguese water systems. Apart from the well-established distribution of M. aeruginosa in Portugal, knowledge of its genetic diversity and population structure is unknown. Therefore, in this study twenty-seven strains were obtained from the North, Centre and South regions of Portugal and were subjected to extensive phylogenetic analyses using simultaneously four distinct genetic markers (16S rRNA, 16S-23S ITS, DNA gyrase subunit ß and cell division protein (ftsZ)) encompassing in total 2834 bp. With this work we characterized the phylogenetic relationship among the Portuguese strains, with the southern strains showing higher genetic structure relatively to the North and Centre strains. A total of fifteen genotypes were determined for M. aeruginosa in Portuguese water systems revealing a high genetic diversity. This is also the first study to report geographic variation on the population structure of the Portuguese M. aeruginosa. PMID:27263013

  1. Structure of a putative acetyltransferase (PA1377) from Pseudomonas aeruginosa

    OpenAIRE

    Davies, Anna M.; Tata, Renée; Chauviac, François-Xavier; Sutton, Brian J; Brown, Paul R.

    2008-01-01

    The crystal structure of an acetyltransferase encoded by the gene PA1377 from Pseudomonas aeruginosa has been determined at 2.25 Å resolution. Comparison with a related acetyltransferase revealed a structural difference in the active site that was taken to reflect a difference in substrate binding and/or specificity between the two enzymes.

  2. Mass Spectrometric Characterization of Oligomers in Pseudomonas aeruginosa Azurin Solutions

    Czech Academy of Sciences Publication Activity Database

    Sokolová, L.; Williamson, H.; Sýkora, Jan; Hof, Martin; Gray, H. B.; Brutschy, B.; Vlček Jr., Antonín

    2011-01-01

    Roč. 115, č. 16 (2011), s. 4790-4800. ISSN 1520-6106 R&D Projects: GA MŠk(CZ) ME10124; GA MŠk(CZ) LC06063 Institutional research plan: CEZ:AV0Z40400503 Keywords : mass spectrometry * oligomers * pseudomonas aeruginosa azurin solutions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.696, year: 2011

  3. 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 of...

  4. Characterization of carbapenem nonsusceptible Pseudomonas aeruginosa in Denmark

    DEFF Research Database (Denmark)

    Hansen, Frank; Johansen, Helle Krogh; Østergaard, Claus;

    2014-01-01

    From January 1st 2011 through June 30th 2011, 116 nonreplicate, noncystic fibrosis-related Pseudomonas aeruginosa isolates with reduced carbapenem susceptibility were collected from 12 out of 13 Danish departments of clinical microbiology. The presence of acquired β-lactamases was assessed with...

  5. 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...

  6. 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...

  7. Ciprofloxacin interactions with imipenem and amikacin against multiresistant Pseudomonas aeruginosa.

    OpenAIRE

    Giamarellou, H; Petrikkos, G

    1987-01-01

    In vitro interactions of ciprofloxacin with imipenem and amikacin were evaluated by the killing-curve technique against 26 Pseudomonas aeruginosa strains resistant to amikacin and resistant or moderately susceptible to ciprofloxacin and imipenem. Imipenem enhanced killing by ciprofloxacin in tests with 11 strains, whereas amikacin enhanced killing in tests with only 4 strains.

  8. Effect of fluid motion on colony formation in Microcystis aeruginosa

    Directory of Open Access Journals (Sweden)

    Lin LI

    2013-01-01

    Full Text Available Microcystis aeruginosa, generally occurring in large colonies under natural conditions, mainly exists as single cells in laboratory cultures. The mechanisms involved in colony formation in Microcystis aeruginosa and their roles in algal blooms remain unknown. In this study, based on previous research findings that fluid motion may stimulate the colony formation in green algae, culture experiments were conducted under axenic conditions in a circular water chamber where the flow rate, temperature, light, and nutrients were controlled. The number of cells of Microcystis aeruginosa, the number of cells per colony, and the colonial characteristics in various growth phases were observed and measured. The results indicated that the colony formation in Microcystis aeruginosa, which was not observed under stagnant conditions, was evident when there was fluid motion, with the number of cells per largest colony reaching 120 and the proportion of the number of cells in colonial form to the total number of cells and the mean number of cells per colony reaching their peak values at a flow rate of 35 cm/s. Based on the analysis of colony formation process, fluid motion stimulates the colony formation in Microcystis aeruginosa in the lag growth phase, while flushes and disaggregates the colonies in the exponential growth phase. The stimulation effect in the lag growth phase may be attributable to the involvement of fluid motion in a series of physiological processes, including the uptake of trace elements and the synthesis and secretion of polysaccharides. In addition, the experimental groups exhibiting typical colonial characteristics in the lag growth phase were found to have higher cell biomass in the later phase.

  9. Antibacterial effect of bismuth subsalicylate nanoparticles synthesized by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Castañeda, Mariela [Instituto Nacional de Investigaciones Nucleares (Mexico); Vega-Jiménez, Alejandro L., E-mail: argelia.almaguer@mac.com; Almaguer-Flores, Argelia [Universidad Nacional Autónoma de México, Facultad de Odontología, DEPeI, I (Mexico); Camps, Enrique; Pérez, Mario [Instituto Nacional de Investigaciones Nucleares (Mexico); Silva-Bermudez, Phaedra [Instituto Nacional de Rehabilitación, Unidad de Ingeniería de Tejidos, Terapia Celular y Medicina Regenerativa (Mexico); Berea, Edgardo [FarmaQuimia SA de CV. (Mexico); Rodil, Sandra E. [Universidad Nacional Autónoma de México, Instituto de Investigaciones en Materiales (Mexico)

    2015-11-15

    The antimicrobial properties of bismuth subsalicylate (BSS) nanoparticles against four opportunistic pathogens; E. coli, P. aeruginosa, S. aureus, and S. epidermidis were determined. BSS nanoparticles were synthesized by pulse laser ablation of a solid target in distilled water under different conditions. The nanoparticles were characterized using high-resolution transmission electron microscopy and absorption spectra and small angle X-ray scattering. The analysis shows that the colloids maintained the BSS structure and presented average particle size between 20 and 60 nm, while the concentration ranges from 95 to 195 mg/L. The antibacterial effect was reported as the inhibition ratio of the bacterial growth after 24 h and the cell viability was measured using the XTT assay. The results showed that the inhibition ratio of E. coli and S. epidermidis was dependant on the NPs size and/or concentration, meanwhile P. aeruginosa and S. aureus were more sensitive to the BSS nanoparticles independently of both the size and the concentration. In general, the BSS colloids with average particle size of 20 nm were the most effective, attaining inhibition ratios >80 %, similar or larger than those obtained with the antibiotic used as control. The results suggest that the BSS colloids could be used as effective antibacterial agents with potential applications in the medical area.

  10. Biosynthesis of silver and zinc oxide nanoparticles using Pichia fermentans JA2 and their antimicrobial property

    Science.gov (United States)

    Chauhan, Ritika; Reddy, Arpita; Abraham, Jayanthi

    2015-01-01

    The development of eco-friendly alternative to chemical synthesis of metal nanoparticles is of great challenge among researchers. The present study aimed to investigate the biological synthesis, characterization, antimicrobial study and synergistic effect of silver and zinc oxide nanoparticles against clinical pathogens using Pichia fermentans JA2. The extracellular biosynthesis of silver and zinc oxide nanoparticles was investigated using Pichia fermentans JA2 isolated from spoiled fruit pulp bought in Vellore local market. The crystalline and stable metallic nanoparticles were characterized evolving several analytical techniques including UV-visible spectrophotometer, X-ray diffraction pattern analysis and FE-scanning electron microscope with EDX-analysis. The biosynthesized metallic nanoparticles were tested for their antimicrobial property against medically important Gram positive, Gram negative and fungal pathogenic microorganisms. Furthermore, the biosynthesized nanoparticles were also evaluated for their increased antimicrobial activities with various commercially available antibiotics against clinical pathogens. The biosynthesized silver nanoparticles inhibited most of the Gram negative clinical pathogens, whereas zinc oxide nanoparticles were able to inhibit only Pseudomonas aeruginosa. The combined effect of standard antibiotic disc and biosynthesized metallic nanoparticles enhanced the inhibitory effect against clinical pathogens. The biological synthesis of silver and zinc oxide nanoparticles is a novel and cost-effective approach over harmful chemical synthesis techniques. The metallic nanoparticles synthesized using Pichia fermentans JA2 possess potent inhibitory effect that offers valuable contribution to pharmaceutical associations.

  11. Effect of Pseudomonas aeruginosa Pure Exotoxin A on Mice WBC in Comparison with Human WBC Contaminated by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    M Naghmachi

    2008-12-01

    Full Text Available ABSTRACT Introduction & Objective: Pseudomonas aeruginosa is a gram negative bacterial. This bacterium is resistant to many antibiotics and chemical disinfectants. Pseudomonas aeruginosa is an opportunistic bacteria and caused infection in skin, external ear, upper respiratory tract, large intestine and is an important bacteria in nosocomial infections. It causes acute infection in burn disease. This bacterium can produce exotoxin A and effect on elongation factor II and can stop protein synthesis. The aim of this study was to evaluate the effect of exotoxin A on mice WBC and comparison of the results with human WBC that contaminated with Pseudomonas aeruginosa. Materials & Methods: This is an experimental study which was conducted in 1384 on burn disease patients referred to Shiraz Ghotbodin hospital. Sample that contaminated with PA was taken from these patients for WBC count and WBC differentiation. Sample was also taken from 100 burn patients without infection (50 male and 50 female. Toxigenic strain of PA103 was cultured on liquid media and used for purification of exotoxin A. This sample was injected to 50 mice (I.V and after different incubation time, WBC was counted. Ten normal mice was used as control. Collected data analyzed by SPSS. Results: WBC count decreased in mice that received Pseudomonas aeruginosa exotoxin A in comparison with normal mice (P<0.05. WBC count was significantly decreased in burn patients in comparison with normal individuals (P<0.029 and most decrease was belonged to PMN. Conclusion: The results demonstrated that Pseudomonas aeruginosa that produce exotoxin induce WBC decrease in burn disease and also in mice that contaminated with exotoxin of this bacteria. It can be concluded that bacterial infection in burn patients is toxigenic strain of PA that produce exotoxin A.

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

    Science.gov (United States)

    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

  13. Synthesis of Silver-Doped Titanium TiO2 Powder-Coated Surfaces and Its Ability to Inactivate Pseudomonas aeruginosa and Bacillus subtilis

    International Nuclear Information System (INIS)

    Hard, non porous environmental surfaces in daily life are now receiving due recognition for their role in reducing the spread of several nosocomial infections. In this work, we established the photo killing effects of 1% silver-doped titanium dioxide TiO2. The nanoparticles synthesized by liquid impregnation method were characterized using X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). The Ag-TiO2 nanoparticle coatings that have been applied on glass and venetian blind surfaces were effective in generating a loss of viability of two bacteria (Pseudomonas aeruginosa and Bacillus subtilis) after two hours of illumination under normal light in the visible spectrum. Such surfaces can be applicable to medical and other facilities where the potential for infection should be controlled

  14. Synthesis of Silver-Doped Titanium TiO2 Powder-Coated Surfaces and Its Ability to Inactivate Pseudomonas aeruginosa and Bacillus subtilis

    Directory of Open Access Journals (Sweden)

    Saman Khan

    2013-01-01

    Full Text Available Hard, nonporous environmental surfaces in daily life are now receiving due recognition for their role in reducing the spread of several nosocomial infections. In this work, we established the photokilling effects of 1% silver-doped titanium dioxide TiO2. The nanoparticles synthesized by liquid impregnation method were characterized using X-ray diffraction (XRD, energy dispersive spectroscopy (EDS, and scanning electron microscopy (SEM. The Ag-TiO2 nanoparticle coatings that have been applied on glass and venetian blind surfaces were effective in generating a loss of viability of two bacteria (Pseudomonas aeruginosa and Bacillus subtilis after two hours of illumination under normal light in the visible spectrum. Such surfaces can be applicable to medical and other facilities where the potential for infection should be controlled.

  15. Mycosynthesis of silver nanoparticles using extract of endophytic fungi, Penicillium species of Glycosmis mauritiana, and its antioxidant, antimicrobial, anti-inflammatory and tyrokinase inhibitory activity

    Science.gov (United States)

    Govindappa, M.; Farheen, H.; Chandrappa, C. P.; Channabasava; Rai, Ravishankar V.; Raghavendra, Vinay B.

    2016-09-01

    Silver nanoparticles were synthesized using endophytic fungal species, Penicillium species from Glycosmis mautitiana. Phytochemicals, namely tannins, saponins, terpenoids and flavonoids, were identified in Penicillium species extracts, and act as agents of reducing and capping in the conversion of silver nanoparticles into nanoparticles. Using SEM, UV-spectroscopy and XRD, the Penicillium species silver nanoparticles (PsAgNPs) were characterized. The PsAgNPs are shown to be strong antioxidants (DDPH and FRAP), have demonstrated anti-inflammatory properties by three different methods in vitro and strongly inhibited the activity of xanthine oxidase, lipoxygenase and tyrosine kinase. E. coli and P. aeruginosa bacterial species were strongly inhibited by PsAgNPs activity at maximum levels and SEM picture of P. aeruginosa confirms these effects and that they were shrunken due to the toxic effect of PsAgNPs.

  16. Antibodies against Pseudomonas aeruginosa chromosomal beta-lactamase inpatients with cystic fibrosis are markers of the development of resistance of P. aeruginosa to beta-lactams

    DEFF Research Database (Denmark)

    Ciofu, O; Giwercman, B; Walter-Rasmussen, J; Pressler, T; Pedersen, S S; Høiby, N

    1995-01-01

    Chromosomal beta-lactamase production is considered to be the most important resistance mechanism of Pseudomonas aeruginosa against beta-lactams. Recently we have detected serum and sputum antibodies against P. aeruginosa chromosomal beta-lactamase (a beta ab), using immunoblotting techniques. In...

  17. Toxicogenomic response of Pseudomonas aeruginosa to ortho-phenylphenol

    Directory of Open Access Journals (Sweden)

    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

  18. Intermetallic nanoparticles

    Science.gov (United States)

    Singh, Dileep; Yusufoglu, Yusuf; Timofeeva, Elena; Routbort, Jules

    2015-07-14

    A process for preparing intermetallic nanoparticles of two or more metals is provided. In particular, the process includes the steps: a) dispersing nanoparticles of a first metal in a solvent to prepare a first metal solution, b) forming a reaction mixture with the first metal solution and a reducing agent, c) heating the reaction mixture to a reaction temperature; and d) adding a second metal solution containing a salt of a second metal to the reaction mixture. During this process, intermetallic nanoparticles, which contain a compound with the first and second metals are formed. The intermetallic nanoparticles with uniform size and a narrow size distribution is also provided. An electrochemical device such as a battery with the intermetallic nanoparticles is also provided.

  19. Green synthesis of silver nanoparticles using Alternanthera dentata leaf extract at room temperature and their antimicrobial activity

    Science.gov (United States)

    Kumar, Deenadayalan Ashok; Palanichamy, V.; Roopan, Selvaraj Mohana

    2014-06-01

    A green rapid biogenic synthesis of silver nanoparticles AgNPs using Alternanthera dentata (A. dentata) aqueous extract was demonstrated in this present study. The formation of silver nanoparticles was confirmed by Surface Plasmon Resonance (SPR) at 430 nm using UV-visible spectrophotometer. The reduction of silver ions to silver nanoparticles by A. dentata extract was completed within 10 min. Synthesized nanoparticles were characterized using UV-visible spectroscopy; Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy (TEM). The extracellular silver nanoparticles synthesis by aqueous leaf extract demonstrates rapid, simple and inexpensive method comparable to chemical and microbial methods. The colloidal solution of silver nanoparticles were found to exhibit antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia and, Enterococcus faecalis.

  20. CHEMICALLY FABRICATED SILVER NANOPARTICLES ENHANCES THE ACTIVITY OF ANTIBIOTICS AGAINST SELECTED HUMAN BACTERIAL PATHOGENS

    Directory of Open Access Journals (Sweden)

    S. Thangapandiyan and P. Prema*

    2012-05-01

    Full Text Available Due to the outbreak of infectious diseases caused by different pathogenic bacteria and the development of antibiotic resistance, the pharmaceutical companies and the researchers are now searching for new unconventional antibacterial agents. Nanotechnology represents a modern and innovative approach to develop new formulations based on metallic nanoparticles with antimicrobial properties. The potential bioactivity of chemically fabricated silver nanoparticles has been extensively studied. However, the antibacterial activity of silver nanoparticles individually or in combination with different antibiotics has not been demonstrated. In the present investigations, the effect of silver nanoparticles on the antibacterial activity of different antibiotics was evaluated against selected human bacterial pathogens such as Staphylococcus aureus, Streptococcus epidermis, Escherichia coli, Pseudomonas aeruginosa, and Bacillus cereus by disc diffusion method. In the presence of sub - inhibitory concentration of silver nanoparticles (100µL/disc, the antibacterial activities of all antibiotics are increased from 1 mm to 10 mm. The maximum fold increase was noticed for vancomycin against Pseudomonas aeruginosa (66.67%, Escherichia coli (62.50%, and Staphylococcus aureus (46% followed by rifampicin against Bacillus cereus (66.67% and kanamycin against Streptococcus epidermis (25%. These results signify that the silver nanoparticles showed potential antibacterial action of ß-lactams, glycopeptides, aminoglycosides, sulphonamides suggesting a possible utilization of silver nanocompounds in combination therapy against selected pathogens used in the experiment.

  1. Antimicrobial Activity of Carbon Nanoparticles Isolated from Natural Sources against Pathogenic Gram-Negative and Gram-Positive Bacteria

    International Nuclear Information System (INIS)

    This paper describes the isolation of carbon nanoparticles (CNPs) from kitchen soot, characterization of the CNPs by UV/visible spectroscopy, SEM and XRD, and their antimicrobial action. The antibacterial activity of the isolated carbon nanoparticles was tested against various pathogenic bacterial strains such as Gram-negative Proteus refrigere and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus and Streptococcus haemolyticus. The inhibition zones were measured, and it was found that the carbon nanoparticles isolated from natural sources are active against these Gram-negative and Gram-positive bacterial strains

  2. Antimicrobial Activity of Carbon Nanoparticles Isolated from Natural Sources against Pathogenic Gram-Negative and Gram-Positive Bacteria

    Directory of Open Access Journals (Sweden)

    Sheena Varghese

    2013-01-01

    Full Text Available This paper describes the isolation of carbon nanoparticles (CNPs from kitchen soot, characterization of the CNPs by UV/visible spectroscopy, SEM and XRD, and their antimicrobial action. The antibacterial activity of the isolated carbon nanoparticles was tested against various pathogenic bacterial strains such as Gram-negative Proteus refrigere and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus and Streptococcus haemolyticus. The inhibition zones were measured, and it was found that the carbon nanoparticles isolated from natural sources are active against these Gram-negative and Gram-positive bacterial strains.

  3. Attenuation of Pseudomonas aeruginosa virulence by quorum sensing inhibitors

    DEFF Research Database (Denmark)

    Hentzer, Morten; Wu, H.; Andersen, Jens Bo;

    2003-01-01

    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 of...... systems 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......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...

  4. The Psl economy in early P. aeruginosa biofilm development

    Science.gov (United States)

    Zhao, Kun; Tseng, Boo Shan; Jin, Fan; Gibiansky, Max; Harrison, Joe; Parsek, Matthew; Wong, Gerard

    2012-02-01

    Psl from P. aeruginosa (PAO1) is a mannose- and galactose-rich exopolysaccharide (EPS). It has been shown that Psl plays an important role in bacterial surface adhesion. Here, we examine role of Psl in controlling motility and microcolony formation during early biofilm development, by translating video microscopy movies into searchable databases of bacterial trajectories. We use a massively-parallel cell tracking algorithm to extract the full motility history of every cell in a large community. We find that at early stages of growth, P. aeruginosa motility is guided by Psl and self-organize in a manner analogous to a capitalist economic system, resulting in a power law bacterial distribution where a small number of bacteria are extremely ``rich'' in communally produced Psl. By comparing overproducers and underproducers of Psl, we find that local Psl levels determine post-division cell fates: High local Psl levels drive the formation of sessile microcolonies that grow exponentially.

  5. Structure of a putative acetyltransferase (PA1377) from Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    The crystal structure of an acetyltransferase encoded by the gene PA1377 from Pseudomonas aeruginosa has been determined at 2.25 Å resolution. Comparison with a related acetyltransferase revealed a structural difference in the active site that was taken to reflect a difference in substrate binding and/or specificity between the two enzymes. Gene PA1377 from Pseudomonas aeruginosa encodes a 177-amino-acid conserved hypothetical protein of unknown function. The structure of this protein (termed pitax) has been solved in space group I222 to 2.25 Å resolution. Pitax belongs to the GCN5-related N-acetyltransferase family and contains all four sequence motifs conserved among family members. The β-strand structure in one of these motifs (motif A) is disrupted, which is believed to affect binding of the substrate that accepts the acetyl group from acetyl-CoA

  6. Improved production of rhamno lipids by a pseudomonas aeruginosa mutant

    International Nuclear Information System (INIS)

    A pseudomonas aeruginosa mutant derived by random mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine, producing high level of the rhamno lipid bio surfactants was selected on Sigmund Wagner plates. The mutant designated P. aeruginosa Persian Type Culture Collection 1637 produces rhamno lipids at concentration 10 times more than present strain. Nuclear Magnetic Resonance analysis and surface tension measurement showed that the bio surfactants produced by the mutant were identical to those produced by the wild type strain. The bio surfactants exhibited a low surface tension of 28.0 mn m-1 and a low critical micelle concentration of 9 mg l-1. Similar to the wild type strain, the mutant produced bio surfactants at the stationary phase

  7. Hemorrhagic pneumonia in mink caused by Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Salomonsen, Charlotte Mark

    hemorrhagic pneumonia caused by P. aeruginosa and E. coli in diagnostic material. The distribution of the two pathogens is visualized using fluorescence in situ hybridization (FISH). Two histological patterns were observed in the work presented in Article II; one was very hemorrhagic with few bacteria while...... pneumonia associated with E. coli infection. The perivascular localization, tendency for a higher frequency of a very hemorrhagic response and alveolar edema were the only differences noted between hemorrhagic pneumonia caused by P. aeruginosa compared to E. coli. Article III describes an infectious dose...... the interviews with farmers 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...

  8. The implication of Pseudomonas aeruginosa biofilms in infections

    DEFF Research Database (Denmark)

    Rybtke, Morten Theil; Jensen, Peter Ø; Høiby, Niels; Givskov, Michael Christian; Tolker-Nielsen, Tim; Bjarnsholt, Thomas

    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 of...... 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 againstP. aeruginosa are described including, quorum-sensing inhibition and induced biofilm-dispersion. The tolerance towards currently available antimicrobials calls for development of alternative...

  9. 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...... 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 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...

  10. In vitro inhibition of Pseudomonas aeruginosa adhesion by Xylitol

    OpenAIRE

    Letícia Pinheiro de Sousa; Annelisa Farah da Silva; Natalia Oliveira Calil; Murilo Gomes Oliveira; Silvio Silvério da Silva; Nádia Rezende Barbosa Raposo

    2011-01-01

    This study evaluated, in vitro, the antimicrobial activity and the anti-adherent property of xylitol (0.5, 2.5 and 5.0%, w/v) on two Pseudomonas aeruginosa strains (ATCC 9027 and clinical). The assay of antimicrobial activity was performed to determine a minimum inhibitory concentration (MIC) and the adhesion test was performed, by which the parameters regarding, growth in the culture medium, number of colony forming units (CFUs) released and slide evaluation by scanning electron microscopy (...

  11. Hydrocarbon assimilation and biosurfactant production in Pseudomonas aeruginosa mutants.

    OpenAIRE

    Koch, A K; Käppeli, O; Fiechter, A; Reiser, J.

    1991-01-01

    We isolated transposon Tn5-GM-induced mutants of Pseudomonas aeruginosa PG201 that were unable to grow in minimal media containing hexadecane as a carbon source. Some of these mutants lacked extracellular rhamnolipids, as shown by measuring the surface and interfacial tensions of the cell culture supernatants. Furthermore, the concentrated culture media of the mutant strains were tested for the presence of rhamnolipids by thin-layer chromatography and for rhamnolipid activities, including hem...

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

    Institute of Scientific and Technical Information of China (English)

    XIE Yi; JIA Wen-xiang; ZENG Wei; YANG Wei-qing; CHENG Xi; LI Xue-ru; WANG Lan-lan; KANG Mei; ZHANG Zai-rong

    2005-01-01

    Background 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. Methods 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.Results 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 (P0.05). The carbonyl cyanide m-chlorophenylhydrazone and azithromycin could significantly reduce the drug resistance of biofilm strains and efflux pump strains.Conclusions 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.

  13. [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. PMID:1633018

  14. Nanoscale Adhesion Forces of Pseudomonas aeruginosa Type IV Pili

    OpenAIRE

    Beaussart, Audrey; Baker, Amy E.; Kuchma, Sherry L.; El-Kirat-Chatel, Sofiane; O’Toole, George A; Yves F Dufrêne

    2014-01-01

    A variety of bacterial pathogens use nanoscale protein fibers called type IV pili to mediate cell adhesion, a primary step leading to infection. Currently, how these nanofibers respond to mechanical stimuli and how this response is used to control adhesion is poorly understood. Here, we use atomic force microscopy techniques to quantify the forces guiding the adhesion of Pseudomonas aeruginosa type IV pili to surfaces. Using chemical force microscopy and single-cell force spectroscopy, we sho...

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

    OpenAIRE

    Luyan Ma; Matthew Conover; Haiping Lu; Parsek, Matthew R.; Kenneth Bayles; Wozniak, Daniel J.

    2009-01-01

    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 organis...

  16. Variability in Pseudomonas aeruginosa Lipopolysaccharide Expression during Crude Oil Degradation

    OpenAIRE

    Norman, R. Sean; Frontera-Suau, Roberto; Morris, Pamela J.

    2002-01-01

    Bacterial utilization of crude oil components, such as the n-alkanes, requires complex cell surface adaptation to allow adherence to oil. To better understand microbial cell surface adaptation to growth on crude oil, the cell surface characteristics of two Pseudomonas aeruginosa strains, U1 and U3, both isolated from the same crude oil-degrading microbial community enriched on Bonny Light crude oil (BLC), were compared. Analysis of growth rates demonstrated an increased lag time for U1 cells ...

  17. Fosfomycin Enhances the Active Transport of Tobramycin in Pseudomonas aeruginosa

    OpenAIRE

    MacLeod, David L.; Velayudhan, Jyoti; Kenney, Thomas F.; Therrien, Joseph H.; Sutherland, Jennifer L.; Barker, Lynn M.; Baker, William R.

    2012-01-01

    Elevated levels of mucins present in bronchiectatic airways predispose patients to bacterial infections and reduce the effectiveness of antibiotic therapies by directly inactivating antibiotics. Consequently, new antibiotics that are not inhibited by mucins are needed to treat chronic respiratory infections caused by Pseudomonas aeruginosa and Staphylococcus aureus. In these studies, we demonstrate that fosfomycin synergistically enhances the activity of tobramycin in the presence of mucin. T...

  18. Quinolone accumulation in Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.

    OpenAIRE

    McCaffrey, C; Bertasso, A; Pace, J.; Georgopapadakou, N H

    1992-01-01

    The accumulation of quinolones by Escherichia coli JF568, Pseudomonas aeruginosa PAO1, and Staphylococcus aureus ATCC 29213 was measured by a modified fluorometric assay (J. S. Chapman and N. H. Georgopapadakou, Antimicrob. Agents Chemother. 33:27-29, 1989). The quinolones examined were fleroxacin, pefloxacin, norfloxacin, difloxacin, A56620, ciprofloxacin, ofloxacin, and Ro 09-1168. In all three organisms, uptake was complete in less than 5 min and was proportional to extracellular quinolone...

  19. Identification of genes required for Pseudomonas aeruginosa carnitine catabolism

    OpenAIRE

    Wargo, Matthew J.; Hogan, Deborah A.

    2009-01-01

    Carnitine is a quaternary amine compound prevalent in animal tissues, and a potential carbon, nitrogen and energy source for pathogens during infection. Characterization of activities in Pseudomonas aeruginosa cell lysates has previously shown that carnitine is converted to 3-dehydrocarnitine (3-dhc) which is in turn metabolized to glycine betaine (GB), an intermediate metabolite in the catabolism of carnitine to glycine. However, the identities of the enzymes required for carnitine catabolis...

  20. Characterization of the Polymyxin B Resistome of Pseudomonas aeruginosa

    OpenAIRE

    Fernandez, L.; Alvarez-Ortega, C.; Wiegand, I.; Olivares, J.; Kocincova, D.; Lam, J S; Martinez, J.L.; Hancock, R. E. W.

    2013-01-01

    Multidrug resistance in Pseudomonas aeruginosa is increasingly becoming a threat for human health. Indeed, some strains are resistant to almost all currently available antibiotics, leaving very limited choices for antimicrobial therapy. In many such cases, polymyxins are the only available option, although as their utilization increases so does the isolation of resistant strains. In this study, we screened a comprehensive PA14 mutant library to identify genes involved in changes of susceptibi...

  1. Emergence of colistin resistant Pseudomonas aeruginosa at Tabriz hospitals, Iran

    Directory of Open Access Journals (Sweden)

    Hamid Reza Goli

    2016-03-01

    Full Text Available Background and Objectives: The prevalence of multidrug resistant Pseudomonas aeruginosa is the main reason of new drugs resurgence such as colistin. The main objectives of this study were to determine the antibiotic resistance pattern and the rate of colistin resistance along with its correlation with overexpression of MexAB-OprM and MexXY-OprM efflux pumps among P. aeruginosa isolates.Materials and Methods: Hundred clinical isolates were collected from 100 patients during 6 months in 2014. Susceptibility to the eight antibiotics was investigated using Kirby-Bauer and agar dilution methods. The Quantitative Real-time PCR was used to determine the expression levels of efflux genes.Results: Resistance rates to various antibiotics were as follows: ticarcillin (73%, ciprofloxacin (65%, aztreonam (60%, ceftazidime (55%, gentamicin (55%, imipenem (49%, piperacillin/tazobactam (34% and colistin (2%. In disk diffusion method, only two isolates were non susceptible to colistin, however in agar dilution method the two isolates were confirmed as resistant and two others were intermediate resistant. Sixty eight (68% isolates were multi-drug resistant and 10 isolates were susceptible to all tested antibiotics. Both colistin resistant isolates showed overexpression of both efflux pumps, but two intermediate resistant isolates exhibited reduction of efflux genes expression.Conclusions: Emergence of colistin resistance is increasing in P. aeruginosa indicating great challenge in the treatment of infections caused by MDR strains of this organism in Iran. ParRS may promote either induced or constitutive resistance to colistin through the activation of distinct mechanisms such as MDR efflux pumps, and LPS modification. Keywords: Pseudomonas aeruginosa, Multi drug resistant, Colistin, MexAB-OprM, MexXY-OprM

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

    OpenAIRE

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

    2015-01-01

    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 fact...

  3. Polysaccharide of the slime glycolipoprotein of Pseudomonas aeruginosa.

    OpenAIRE

    Koepp, L H; Orr, T.; Bartell, P F

    1981-01-01

    The polysaccharide moiety was isolated by mild acid hydrolysis from the slime glycolipoprotein of Pseudomonas aeruginosa strain BI. After gel filtration, the polysaccharide obtained from the Carbohydrate peak fractions was found to be lipid- and protein-free. Analyses indicated that the polysaccharide contained the carbohydrate components of the parent glycolipoprotein. Molecular size of the polysaccharide was estimated by gel filtration as 70,000 to 100,000. The polysaccharide showed no indi...

  4. Pseudomonas aeruginosa in the Early Childhood: A Case Report

    OpenAIRE

    Roberto Braga de CarvalhoVianna; Rodolfo de Almeida Lima Castro; Marta Lua Pimentel Winz Almeida; Andréa Gonçalves Antonio; Flávia dos Santos Moraes

    2008-01-01

    Pseudomonas aeruginosa is an opportunistic bacterium that usually affects immunocompromised patients, causing infections whose signals and symptoms are related to the affected organ. The patient presented in this article was infected when he was 9 months old. Such condition led to certain alterations like dental improperly positioned teeth, retained deciduous teeth, hipodonty of permanent teeth, atrophy of the upper jaw and dental crowding. Therefore, the purpose of this article is to report ...

  5. Secretion of Elastinolytic Enzymes and Their Propeptides by Pseudomonas aeruginosa

    OpenAIRE

    Braun, Peter; de Groot, Arjan; Bitter, Wilbert; Tommassen, Jan

    1998-01-01

    Elastase of Pseudomonas aeruginosa is synthesized as a preproenzyme. The signal sequence is cleaved off 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 propeptide is degraded extracellularly. In addition, reduction of the extracellular proteolytic activity led to the accumulation of unprocessed forms of LasA and LasD in the extracellular medium, which s...

  6. Biofilm Formation by Hyperpiliated Mutants of Pseudomonas aeruginosa

    OpenAIRE

    Chiang, Poney; Burrows, Lori L.

    2003-01-01

    Under static growth conditions, hyperpiliated, nontwitching pilT and pilU mutants of Pseudomonas aeruginosa formed dense biofilms, showing that adhesion, not twitching motility, is necessary for biofilm initiation. Under flow conditions, the pilT mutant formed mushroom-like structures larger than those of the wild type but the pilU mutant was defective in biofilm formation. Therefore, twitching motility affects the development of biofilm structure, possibly through modulation of detachment.

  7. Pseudomonas aeruginosa Displays Multiple Phenotypes during Development as a Biofilm

    OpenAIRE

    Sauer, Karin; Anne K. Camper; Ehrlich, Garth D.; Costerton, J. William; Davies, David G

    2002-01-01

    Complementary approaches were employed to characterize transitional episodes in Pseudomonas aeruginosa biofilm development using direct observation and whole-cell protein analysis. Microscopy and in situ reporter gene analysis were used to directly observe changes in biofilm physiology and to act as signposts to standardize protein collection for two-dimensional electrophoretic analysis and protein identification in chemostat and continuous-culture biofilm-grown populations. Using these appro...

  8. Characterization of Temporal Protein Production in Pseudomonas aeruginosa Biofilms†

    OpenAIRE

    Southey-Pillig, Christopher J.; Davies, David G; Sauer, Karin

    2005-01-01

    Phenotypic and genetic evidence supporting the notion of biofilm formation as a developmental process is growing. In the present work, we provide additional support for this hypothesis by identifying the onset of accumulation of biofilm-stage specific proteins during Pseudomonas aeruginosa biofilm maturation and by tracking the abundance of these proteins in planktonic and three biofilm developmental stages. The onset of protein production was found to correlate with the progression of biofil...

  9. Biotransformation of myrcene by Pseudomonas aeruginosa

    OpenAIRE

    Hashemi Elham; Esmaeili Akbar

    2011-01-01

    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...

  10. Cloning and surface expression of Pseudomonas aeruginosa O antigen in Escherichia coli.

    OpenAIRE

    Goldberg, J B; Hatano, K; Meluleni, G S; Pier, G B

    1992-01-01

    As a step toward developing recombinant oral vaccines, we have explored the feasibility of expression of O polysaccharide antigens from Pseudomonas aeruginosa by Escherichia coli. We cloned in E. coli HB101 a 26.2-kilobase DNA fragment from P. aeruginosa strain PA103 that specifies the production of the O polysaccharide of Fisher immunotype 2 (IT-2) strains. The recombinant organism incorporated the P. aeruginosa IT-2 O polysaccharide onto the core of the E. coli lipopolysaccharide (LPS). Tra...

  11. Recent advances in the treatment of Pseudomonas aeruginosa infections in cystic fibrosis

    DEFF Research Database (Denmark)

    Høiby, Niels

    2011-01-01

    suggest that addition of oral ciprofloxacin to inhaled tobramycin may reduce lung inflammation. Clinical trials with new formulations of old antibiotics for inhalation therapy (aztreonam lysine) against chronic P. aeruginosa infection improved patient-reported outcome, lung function, time to acute...... patients without P. aeruginosa infection did not improve lung function. Here I review the recent advances in the treatment of P. aeruginosa lung infections with a focus on inhalation treatments targeted at prophylaxis and chronic suppressive therapy....

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

    OpenAIRE

    Marvig, Rasmus Lykke; Dolce, Daniela; Madsen Sommer, Lea Mette; Petersen, Bent; Ciofu, Oana; Campana, Silvia; Molin, Søren; Taccetti, Giovanni; Johansen, Helle Krogh

    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 strategies. Here, we report the first genomic analysis of P. aeruginosa isolates sampled from Italian CF patients. By genome sequencing of 26 isolates sampled over 19 years from four patients, we elucidated...

  13. Burn Patients Infected With Metallo-Beta-Lactamase-Producing Pseudomonas aeruginosa: Multidrug-Resistant Strains

    OpenAIRE

    Anvarinejad, Mojtaba; Japoni, Aziz; Rafaatpour, Noroddin; Mardaneh, Jalal; Abbasi, Pejman; Amin Shahidi, Maneli; Dehyadegari, Mohammad Ali; Alipour, Ebrahim

    2014-01-01

    Background: Metallo-beta-lactamase (MBL) producing Pseudomonas aeruginosa in the burn patients is a leading cause of morbidity and mortality and remains a serious health concern among the clinicians. Objectives: The aim of this study was to detect MBL-producing P. aeruginosa in burn patients and determine multidrug-resistant (MDR) strains, and respective resistance patterns. Patients and Methods: In this cross-sectional study, 270 strains of P. aeruginosa were isolated from the burn patients ...

  14. Pseudomonas aeruginosa invasion of and multiplication within corneal epithelial cells in vitro.

    OpenAIRE

    Fleiszig, S M; Zaidi, T S; Pier, G.B. (G.B.)

    1995-01-01

    Pseudomonas aeruginosa is usually considered an extracellular pathogen. Using assays to determine intracellular survival in the presence of gentamicin, we have previously demonstrated that P. aeruginosa is able to invade corneal cells during infectious keratitis in mice. In vitro, P. aeruginosa was found to enter the following cells: human corneal cells removed by irrigation; epithelial cells in the cornea of rats, mice, and rabbits; and primary corneal epithelial cells cultured from rat and ...

  15. Pseudomonas aeruginosa and Klebsiella pneumoniae on the perinea of males with spinal cord injuries.

    OpenAIRE

    Gilmore, D S; Schick, D G; Montgomerie, J Z

    1982-01-01

    Pseudomonas aeruginosa colonization is found in a high percentage of males with spinal cord injury. The perineum is the body site most frequently colonized, and specific serotypes may persist for weeks. We examined patients for the presence of P. aeruginosa and Klebsiella pneumoniae on the perineum and adjacent body sites by using contact plates. P. aeruginosa, K. pneumoniae, or both were cultured from perineal swabs of 22 male patients. Wells (2.5 cm2) containing agar medium selective for th...

  16. Draft Genome Sequences of Pseudomonas aeruginosa Isolates from Wounded Military Personnel

    Science.gov (United States)

    Arivett, Brock A.; Ream, Dave C.; Fiester, Steven E.; Kidane, Destaalem

    2016-01-01

    Pseudomonas aeruginosa, a Gram-negative bacterium that causes severe hospital-acquired infections, is grouped as an ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogen because of its extensive drug resistance phenotypes and effects on human health worldwide. Five multidrug resistant P. aeruginosa strains isolated from wounded military personnel were sequenced and annotated in this work. PMID:27516516

  17. Inhibition of Pseudomonas aeruginosa elastase and Pseudomonas keratitis using a thiol-based peptide.

    OpenAIRE

    Burns, F R; Paterson, C. A.; Gray, R. D.; Wells, J T

    1990-01-01

    Pseudomonas aeruginosa elastase is a zinc metalloproteinase which is released during P. aeruginosa infections. Pseudomonas keratitis, which occurs following contact lens-induced corneal trauma, can lead to rapid, liquefactive necrosis of the cornea. This destruction has been attributed to the release of both host-derived enzymes and the bacterial products P. aeruginosa elastase, alkaline protease, exotoxin A, and lipopolysaccharide endotoxin. A synthetic metalloproteinase inhibitor, HSCH2 (DL...

  18. Draft Genome Sequences of Pseudomonas aeruginosa Isolates from Wounded Military Personnel.

    Science.gov (United States)

    Arivett, Brock A; Ream, Dave C; Fiester, Steven E; Kidane, Destaalem; Actis, Luis A

    2016-01-01

    Pseudomonas aeruginosa, a Gram-negative bacterium that causes severe hospital-acquired infections, is grouped as an ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogen because of its extensive drug resistance phenotypes and effects on human health worldwide. Five multidrug resistant P. aeruginosa strains isolated from wounded military personnel were sequenced and annotated in this work. PMID:27516516

  19. High genetic diversity among Pseudomonas aeruginosa and Acinetobacter spp. isolated in a public hospital in Brazil

    OpenAIRE

    Vera Lúcia Dias Siqueira; Rosilene Fressatti Cardoso; Rubia Andreia Falleiros de Pádua; Katiany Rizzieri Caleffi-Ferracioli; Cesar Helbel; Adolfo Carlos Barreto Santos; Elisabeth Eyko Aoki; Celso Vataru Nakamura

    2013-01-01

    In Brazil and other regions of the world, Pseudomonas aeruginosa and Acinetobacter spp. have emerged as important agents of nosocomial infection and are commonly involved in outbreaks. The main objective of the present study was to evaluate the genetic relationship among P. aeruginosa and Acinetobacter spp. isolated from patients in a public university hospital in northwestern Paraná, Brazil, and report their antimicrobial resistance profile. A total of 75 P. aeruginosa and 94 Acinetobacter s...

  20. Inhibitory activity of Iranian plant extracts on growth and biofilm formation by Pseudomonas aeruginosa

    OpenAIRE

    S Mansouri; Safa, A.; Najar, S. G.; Najar, A. G.

    2013-01-01

    Aims: Pseudomonas aeruginosa is a drug resistance opportunistic bacterium. Biofilm formation is key factor for survivalof P. aeruginosa in various environments. Polysaccharides may be involved in biofilm formation. The purpose of thisstudy was to evaluate antimicrobial and anti-biofilm activities of seven plant extracts with known alpha-glucosidaseinhibitory activities on different strains of P. aeruginosa.Methodology and results: Plants were extracted with methanol by the maceration method. ...

  1. Characterization of antibody-mediated inhibition of Pseudomonas aeruginosa adhesion to epithelial cells.

    OpenAIRE

    Sexton, M; Reen, D J

    1992-01-01

    An enzyme-linked immunosorbent assay system was developed and used to study adhesion of Pseudomonas aeruginosa to human epithelial cells and the abilities of specific antibodies to inhibit this process. Human buccal epithelial cells coated onto microtiter plates were incubated with P. aeruginosa suspensions, and adherent bacteria were detected by using anti-P. aeruginosa serum and a horseradish peroxidase-conjugated secondary antiserum. Adhesion, quantitated as an increase in A405, varied lin...

  2. Molecular identification and detection of virulence genes among Pseudomonas aeruginosa isolated from different infectious origins

    OpenAIRE

    Vajiheh Sadat Nikbin; Mohammad Mehdi Aslani; Marjan Hashemipour; Zeinab Sharafi; Fereshteh Shahcheraghi; Gholamhossein Ebrahimipour

    2012-01-01

    BACKGROUND AND OBJECTIVES: Pseudomonas aeruginosa possesses a variety of virulence factors that may contribute to its pathogenicity. The aim of this study was to evaluate oprI, oprL and toxA genes for PCR identification of clinical P. aeruginosa. In order to find out any relation between special virulence factors and special manifestation of P. aeruginosa infections, we detected virulence factors among these isolates by PCR. Ribotyping was used to evaluate the clonal relationship between stra...

  3. Pseudomonas aeruginosa bacteraemia in two UK district hospitals

    Directory of Open Access Journals (Sweden)

    David A. Enoch

    2013-09-01

    Full Text Available Pseudomonas aeruginosa bacteraemia is associated with significant morbidity and mortality. We retrospectively studied the epidemiology of bacteraemia due to P. aeruginosa in two UK district hospitals so as to determine prevention strategies and assess the efficacy and compliance with local hospital antibiotic guidelines. Eighty six episodes occurred in 85 patients over the 3 year period. There was a year on year increase in bacteraemias, due predominantly to an increased proportion of community-onset episodes. Urinary catheterisation was a significant risk factor, along with anaemia, renal disease, malignancy and diabetes. The antibiotic guidelines were adequate for 92.8% of episodes but only 73.8% of patients received adequate therapy. Failure to follow the guidelines was principally due to unwillingness to use gentamicin due to concerns about nephrotoxicity. The antibiotic guidelines may need reviewing to accommodate this problem and further work is required to address urinary catheter care in both the hospital and community. Pseudomonas aeruginosa should be considered a significant pathogen when patients are admitted with features of sepsis.

  4. INHIBITION OF VIRULENCE FACTORS OF PSEUDOMONAS AERUGINOSA BY DICLOFENAC SODIUM.

    Science.gov (United States)

    Abbas, Hisham A

    2015-01-01

    Resistance of Pseudomonas aeruginosa to antibiotics is a major problem. Targeting virulence factors is an alternative option to avoid the emergence of resistance to antibiotics. The effect of sub-inhibitory concentration of diclofenac sodium on the production of virulence factors of P. aeruginosa was investigated. The virulence factors included protease, haemolysin, pyocyanin and pyoverdin, in addition to pathogenic behaviors such as swimming and twitching motilities and biofilm formation. Diclofenac sodium showed significant inhibition of virulence factors as compared to the control. Diclofenac sodium decreased twitching and swimming motilities by 29.27% and 45.36%, respectively. The percentage of inhibition of pyocyanin by diclofenac sodium was 42.32%. On the other hand, pyoverdin was inhibited to a lesser extent (36.72%). Diclofenac sodium reduced protease by 52.58% and biofilm formation by 58.37%. Moreover, haemolytic activity in the presence of diclofenac sodium was 15.64% as compared to the control (100% haemolytic activity). The inhibitory activities may be due to inhibition of quorum sensing that regulates the expression of virulence factors. This study suggests the potential for the use of diclofenac sodium as an anti-virulence agent in the treatment of Pseudomonas aeruginosa infections. PMID:27328521

  5. Arsenic efflux from Microcystis aeruginosa under different phosphate regimes.

    Directory of Open Access Journals (Sweden)

    Changzhou Yan

    Full Text Available Phytoplankton plays an important role in arsenic speciation, distribution, and cycling in freshwater environments. Little information, however, is available on arsenic efflux from the cyanobacteria Microcystis aeruginosa under different phosphate regimes. This study investigated M. aeruginosa arsenic efflux and speciation by pre-exposing it to 10 µM arsenate or arsenite for 24 h during limited (12 h and extended (13 d depuration periods under phosphate enriched (+P and phosphate depleted (-P treatments. Arsenate was the predominant species detected in algal cells throughout the depuration period while arsenite only accounted for no greater than 45% of intracellular arsenic. During the limited depuration period, arsenic efflux occurred rapidly and only arsenate was detected in solutions. During the extended depuration period, however, arsenate and dimethylarsinic acid (DMA were found to be the two predominant arsenic species detected in solutions under -P treatments, but arsenate was the only species detected under +P treatments. Experimental results also suggest that phosphorus has a significant effect in accelerating arsenic efflux and promoting arsenite bio-oxidation in M. aeruginosa. Furthermore, phosphorus depletion can reduce arsenic efflux from algal cells as well as accelerate arsenic reduction and methylation. These findings can contribute to our understanding of arsenic biogeochemistry in aquatic environments and its potential environmental risks under different phosphorus levels.

  6. Inquisition of Microcystis aeruginosa and Synechocystis nanowires: characterization and modelling.

    Science.gov (United States)

    Sure, Sandeep; Torriero, Angel A J; Gaur, Aditya; Li, Lu Hua; Chen, Ying; Tripathi, Chandrakant; Adholeya, Alok; Ackland, M Leigh; Kochar, Mandira

    2015-11-01

    Identification of extracellular conductive pilus-like structures (PLS) i.e. microbial nanowires has spurred great interest among scientists due to their potential applications in the fields of biogeochemistry, bioelectronics, bioremediation etc. Using conductive atomic force microscopy, we identified microbial nanowires in Microcystis aeruginosa PCC 7806 which is an aerobic, photosynthetic microorganism. We also confirmed the earlier finding that Synechocystis sp. PCC 6803 produces microbial nanowires. In contrast to the use of highly instrumented continuous flow reactors for Synechocystis reported earlier, we identified simple and optimum culture conditions which allow increased production of nanowires in both test cyanobacteria. Production of these nanowires in Synechocystis and Microcystis were found to be sensitive to the availability of carbon source and light intensity. These structures seem to be proteinaceous in nature and their diameter was found to be 4.5-7 and 8.5-11 nm in Synechocystis and M. aeruginosa, respectively. Characterization of Synechocystis nanowires by transmission electron microscopy and biochemical techniques confirmed that they are type IV pili (TFP) while nanowires in M. aeruginosa were found to be similar to an unnamed protein (GenBank : CAO90693.1). Modelling studies of the Synechocystis TFP subunit i.e. PilA1 indicated that strategically placed aromatic amino acids may be involved in electron transfer through these nanowires. This study identifies PLS from Microcystis which can act as nanowires and supports the earlier hypothesis that microbial nanowires are widespread in nature and play diverse roles. PMID:26319534

  7. 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.

  8. 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.

  9. Light intensity adaptation and phycobilisome composition of Microcystis aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Raps, S.; Kycia, J.H.; Ledbetter, M.C.; Siegelman, H.W.

    1985-12-01

    Phycobilisomes isolated from Microcystis aeruginosa grown to midlog at high light (270 microeinsteins per square meter per second) or at low light intensities (40 microeinsteins per square meter per second) were found to be identical. Electron micrographs established that they have a triangular central core apparently consisting of three allophycocyanin trimers surrounded by six rods, each composed of two hexameric phycocyanin molecules. The apparent mass of a phycobilisome obtained by gel filtration is 2.96 x 10/sup 6/ daltons. The molar ratio of the phycobiliproteins per phycobilisome is 12 phycocyanin hexamers:9 allophycocyanin trimers. The electron microscopic observations combined with the phycobilisome apparent mass and the phycobiliprotein stoichiometry data indicate that M. aeruginosa phycobilisomes are composed of a triangular central core of three stacks of three allophycocyanin trimers and six rods each containing two phycocyanin hexamers. Adaptation of M. aeruginosa to high light intensity results in a decrease in the number of phycobilisomes per cell with no alteration in phycobilisome composition or structure.

  10. PA3297 Counteracts Antimicrobial Effects of Azithromycin in Pseudomonas aeruginosa.

    Science.gov (United States)

    Tan, Hao; Zhang, Lu; Weng, Yuding; Chen, Ronghao; Zhu, Feng; Jin, Yongxin; Cheng, Zhihui; Jin, Shouguang; Wu, Weihui

    2016-01-01

    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 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. PMID:27014238

  11. PA3297 Counteracts Antimicrobial Effects of Azithromycin in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    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.

  12. Antibacterial and anticancerous biocompatible silver nanoparticles synthesised from the cold-tolerant strain of Spirulina platensis

    Directory of Open Access Journals (Sweden)

    Selvaraj Karthick Raja Namasivayam

    2015-04-01

    Full Text Available Objective: To synthesize silver nanoparticles from the biomass of cold tolerant strain of Spirulina platensis and evalute the synthesized nanoparticles against antibacterial and anticancer activity. Methods: Silver nanoparticles were synthesized by the algal culture and characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and X ray diffraction studies. Antibacterial activity has been studied with free nanoparticles adopting agar diffusion assay, biofilm inhibition assay and nanoparticles fabricated wound dressing against representative Gram-negative organism Pseudomonas aeruginosa and Gram-positive organism Staphylococcus aureus respectively. The in vitro anticancer activity of silver nanoparticles were screened against human Hep2 cell lines by means of MTT assay. Results: Reduction of silver ions by the algal culture was observed during 72 h of incubation and the synthesized nanoparticles were further characterized. Antibacterial study reveals both the strains were susceptible to free nanoparticles and fabricated wound dressing treatment. The in vitro anticancer activity of silver nanoparticles were screened against human Hep 2 cell lines by means of MTT assay which reveals that cell viability has been reduced as dose dependent manner. Conclusions: The observed results imply that silver nanoparticles synthesized from Spirulina platensis cold tolerant strain can be used as potential antibacterial and anticancerous agent.

  13. Antibacterial and anticancerous biocompatible silver nanoparticles synthesised from the cold-tolerant strain of Spirulina platensis

    Institute of Scientific and Technical Information of China (English)

    Duraisamy Jayakumar; Ramesh Kumar; Rajan SowriArvind Bharani

    2015-01-01

    Objective: To synthesize silver nanoparticles from the biomass of cold tolerant strain of Spirulina platensis and evalute the synthesized nanoparticles against antibacterial and anticancer activity. Methods: Silver nanoparticles were synthesized by the algal culture and characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and X ray diffraction studies. Antibacterial activity has been studied with free nanoparticles adopting agar diffusion assay, biofilm inhibition assay and nanoparticles fabricated wound dressing against representative Gram-negative organism Pseudomonas aeruginosa and Gram-positive organism Staphylococcus aureus respectively. The in vitro anticancer activity of silver nanoparticles were screened against human Hep2 cell lines by means of MTT assay. Results: Reduction of silver ions by the algal culture was observed during 72 h of incubation and the synthesized nanoparticles were further characterized. Antibacterial study reveals both the strains were susceptible to free nanoparticles and fabricated wound dressing treatment. The in vitro anticancer activity of silver nanoparticles were screened against human Hep 2 cell lines by means of MTT assay which reveals that cell viability has been reduced as dose dependent manner. Conclusions: The observed results imply that silver nanoparticles synthesized from Spirulina platensis cold tolerant strain can be used as potential antibacterial and anticancerous agent.

  14. Continued transmission of Pseudomonas aeruginosa from a wash hand basin tap in a critical care unit.

    Science.gov (United States)

    Garvey, M I; Bradley, C W; Tracey, J; Oppenheim, B

    2016-09-01

    Pseudomonas aeruginosa is an important nosocomial pathogen, colonizing hospital water supplies including taps and sinks. We report a cluster of P. aeruginosa acquisitions during a period of five months from tap water to patients occupying the same burns single room in a critical care unit. Pseudomonas aeruginosa cultured from clinical isolates from four different patients was indistinguishable from water strains by pulsed-field gel electrophoresis. Water outlets in critical care may be a source of P. aeruginosa despite following the national guidance, and updated guidance and improved control measures are needed to reduce the risks of transmission to patients. PMID:27249962

  15. Inhibitory effects of sanguinarine against the cyanobacterium Microcystis aeruginosa NIES-843 and possible mechanisms of action

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Jihai [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Agricultural University, Changsha 410128 (China); Liu, Deming [State Key Laboratory Breeding Base of Crop Germplasm Innovation and Resource Utilization, Hunan Agricultural University, Changsha 410128 (China); Gong, Daoxin; Zeng, Qingru; Yan, Zhiyong [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); Gu, Ji-Dong, E-mail: jdgu@hku.hk [Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Agricultural University, Changsha 410128 (China); Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR (China)

    2013-10-15

    Highlights: •Sanguinarine was found as a strong algicidal biologically derived substance. •Sanguinarine can induce oxidative stress in the cells of Microcystis aeruginosa. •Photosystem is a target of toxicity of sanguinarine on M. aeruginosa. •Sanguinarine can induce DNA damage and inhibit cell division. -- Abstract: Sanguinarine showed strong inhibitory effect against Microcystis aeruginosa, a typical water bloom-forming and microcystins-producing cyanobacterium. The EC50 of sanguinarine against the growth of M. aeruginosa NIES-843 was 34.54 ± 1.17 μg/L. Results of chlorophyll fluorescence transient analysis indicated that all the electron donating side, accepting side, and the reaction center of the Photosystem II (PS II) were the targets of sanguinarine against M. aeruginosa NIES-843. The elevation of reactive oxygen species (ROS) level in the cells of M. aeruginosa NIES-843 upon exposure indicated that sanguinarine induced oxidative stress in the active growing cells of M. aeruginosa NIES-843. Further results of gene expression analysis indicated that DNA damage and cell division inhibition were also involved in the inhibitory action mechanism of sanguinarine against M. aeruginosa NIES-843. The inhibitory characteristics of sanguinarine against M. aeruginosa suggest that the ecological- and public health-risks need to be evaluated before its application in cyanobacterial bloom control to avoid devastating events irreversibly.

  16. 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.

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

    DEFF Research Database (Denmark)

    Aanaes, Kasper; Johansen, Helle Krogh; Poulsen, Steen Seier; Pressler, Tacjana; Buchwald, Christian; Høiby, Niels

    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...... colonized or without P. aeruginosa in the lungs participated in this cross-sectional study. IgA and IgG against P. aeruginosa sonicate and alginate were measured in nasal secretions, saliva, and in serum by ELISA. RESULTS: The intermittently colonized patients had significantly higher IgA levels in nasal...

  18. Antibiogram of Multidrug-Resistant Isolates of Pseudomonas aeruginosa after Biofield Treatment

    OpenAIRE

    Mahendra Kumar Trivedi

    2015-01-01

    In recent years, prevalence of multidrug resistance (MDR) in Pseudomonas aeruginosa (P. aeruginosa) has been noticed with high morbidity and mortality. Aim of the present study was to determine the impact of Mr. Trivedi’s biofield treatment on MDR clinical lab isolates (LS) of P. aeruginosa. Five MDR clinical lab isolates (LS 22, LS 23, LS 38, LS 47, and LS 58) of P. aeruginosa were taken and divided into two groups i.e. control and biofield treated. Control and treated group were analy...

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

    OpenAIRE

    Carlos Andrés Gómez Álvarez; Aura Lucía Leal Castro; María de Jesús Pérez de Gonzalez; Myriam Lucía Navarrete Jiménez

    2005-01-01

    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 morbilid...

  20. Effect of Human Burn Wound Exudate on Pseudomonas aeruginosa Virulence.

    Science.gov (United States)

    Gonzalez, Manuel R; Fleuchot, Betty; Lauciello, Leonardo; Jafari, Paris; Applegate, Lee Ann; Raffoul, Wassim; Que, Yok-Ai; Perron, Karl

    2016-01-01

    Burn wound sepsis is currently the main cause of morbidity and mortality after burn trauma. Infections by notorious pathogens such as Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii impair patient recovery and can even lead to fatality. In this study, we investigated the effect of burn wound exudates (BWEs) on the virulence of those pathogens. BWEs were collected within 7 days after burn trauma from 5 burn patients. We first monitored their effect on pathogen growth. In contrast to A. baumannii and S. aureus, P. aeruginosa was the only pathogen able to grow within these human fluids. Expression of typical virulence factors such as pyocyanin and pyoverdine was even enhanced compared the levels seen with standard laboratory medium. A detailed chemical composition analysis of BWE was performed, which enabled us to determine the major components of BWE and underline the metabolic modifications induced by burn trauma. These data are essential for the development of an artificial medium mimicking the burn wound environment and the establishment of an in vitro system to analyze the initial steps of burn wound infections. IMPORTANCE Microbial infection of severe burn wounds is currently a major medical challenge. Of the infections by bacteria able to colonize such injuries, those by Pseudomonas aeruginosa are among the most severe, causing major delays in burn patient recovery or leading to fatal issues. In this study, we investigated the growth properties of several burn wound pathogens in biological fluids secreted from human burn wounds. We found that P. aeruginosa strains were able to proliferate but not those of the other pathogens tested. In addition, burn wound exudates (BWEs) stimulate the expression of virulence factors in P. aeruginosa. The chemical composition analysis of BWEs enabled us to determine the major components of these fluids. These data are essential for the development of an artificial medium mimicking the burn wound

  1. Radiolytic synthesis and antimicrobial activity of polyvinyl alcohol hydrogels containing silver nanoparticles

    International Nuclear Information System (INIS)

    Polyvinyl alcohol (PVA) hydrogels containing silver nanoparticles have been prepared by impregnation of PVA hydrogels in AgNO3 solution and subsequent reduction of Ag+ ions induced by gamma radiation. UV-Visible spectra showed the absorption bands of the surface plasmon at 410 nm. The hydrogels of PVA/Ag have shown excellent activity against S. aureus and P. aeruginosa and have potential for use as wound dressings. (orig.)

  2. The Antibacterial Activity of Ta-doped ZnO Nanoparticles

    Science.gov (United States)

    Guo, Bing-Lei; Han, Ping; Guo, Li-Chuan; Cao, Yan-Qiang; Li, Ai-Dong; Kong, Ji-Zhou; Zhai, Hai-Fa; Wu, Di

    2015-08-01

    A novel photocatalyst of Ta-doped ZnO nanoparticles was prepared by a modified Pechini-type method. The antimicrobial study of Ta-doped ZnO nanoparticles on several bacteria of Gram-positive Bacillus subtilis ( B. subtilis) and Staphylococcus aureus ( S. aureus) and Gram-negative Escherichia coli ( E. coli) and Pseudomonas aeruginosa ( P. aeruginosa) were performed using a standard microbial method. The Ta-doping concentration effect on the minimum inhibitory concentration (MIC) of various bacteria under dark ambient has been evaluated. The photocatalytical inactivation of Ta-doped ZnO nanoparticles under visible light irradiation was examined. The MIC results indicate that the incorporation of Ta5+ ions into ZnO significantly improve the bacteriostasis effect of ZnO nanoparticles on E. coli, S. aureus, and B. subtilis in the absence of light. Compared to MIC results without light irradiation, Ta-doped ZnO and pure ZnO nanoparticles show much stronger bactericidal efficacy on P. aeruginosa, E. coli, and S. aureus under visible light illumination. The possible antimicrobial mechanisms in Ta-doped ZnO systems under visible light and dark conditions were also proposed. Ta-doped ZnO nanoparticles exhibit more effective bactericidal efficacy than pure ZnO in dark ambient, which can be attributed to the synergistic effect of enhanced surface bioactivity and increased electrostatic force due to the incorporation of Ta5+ ions into ZnO. Based on the antibacterial tests, 5 % Ta-doped ZnO is a more effective antimicrobial agent than pure ZnO.

  3. Anti-biofilm and cytotoxicity activity of impregnated dressings with silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Velázquez-Velázquez, Jorge Luis [Laboratorio de Microbiología, Facultad de Ciencias Químicas, UASLP (Mexico); Santos-Flores, Andrés; Araujo-Meléndez, Javier [Servicio de Epidemiología del Hospital Central “Dr. Ignacio Morones Prieto”, San Luis Potosí (Mexico); Sánchez-Sánchez, Roberto; Velasquillo, Cristina [Laboratorio de Biotecnología, Instituto Nacional de Rehabilitación (Mexico); González, Carmen [Laboratorio de Fisiología Celular, Facultad de Ciencias Químicas, UASLP (Mexico); Martínez-Castañon, Gabriel [Maestría en Ciencias Odontológicas Facultad de Estomatología, UASLP (Mexico); Martinez-Gutierrez, Fidel, E-mail: fidel@uaslp.mx [Laboratorio de Microbiología, Facultad de Ciencias Químicas, UASLP (Mexico)

    2015-04-01

    Infections arising from bacterial adhesion and colonization on chronic wounds are a significant healthcare problem. Silver nanoparticles (AgNPs) impregnated in dressing have attracted a great deal of attention as a potential solution. The goal of the present study was to evaluate the anti-biofilm activities of AgNPs impregnated in commercial dressings against Pseudomonas aeruginosa, bacteria isolated of chronic wounds from a hospital patient. The antimicrobial activity of AgNPs was tested within biofilms generated under slow fluid shear conditions using a standard bioreactor. A 2-log reduction in the number of colony-forming units of P. aeruginosa was recorded in the reactor on exposure to dressing impregnated with 250 ppm of AgNPs, diameter 9.3 ± 1.1 nm, and also showed compatibility to mammalian cells (human fibroblasts). Our study suggests that the use of dressings with AgNPs may either prevent or reduce microbial growth in the wound environment, and reducing wound bioburden may improve wound-healing outcomes. - Highlights: • Biological activities of silver nanoparticles for wound-healing purposes • Characterization of the silver nanoparticles impregnated in dressings • Reduction in the P. aeruginosa biofilm formation was statistically significant. • Compatibility to human dermal fibroblasts as the main cell type involved in the reparation • AgNPs covering the surfaces would provide great potential for prevention and treatment.

  4. Anti-biofilm and cytotoxicity activity of impregnated dressings with silver nanoparticles

    International Nuclear Information System (INIS)

    Infections arising from bacterial adhesion and colonization on chronic wounds are a significant healthcare problem. Silver nanoparticles (AgNPs) impregnated in dressing have attracted a great deal of attention as a potential solution. The goal of the present study was to evaluate the anti-biofilm activities of AgNPs impregnated in commercial dressings against Pseudomonas aeruginosa, bacteria isolated of chronic wounds from a hospital patient. The antimicrobial activity of AgNPs was tested within biofilms generated under slow fluid shear conditions using a standard bioreactor. A 2-log reduction in the number of colony-forming units of P. aeruginosa was recorded in the reactor on exposure to dressing impregnated with 250 ppm of AgNPs, diameter 9.3 ± 1.1 nm, and also showed compatibility to mammalian cells (human fibroblasts). Our study suggests that the use of dressings with AgNPs may either prevent or reduce microbial growth in the wound environment, and reducing wound bioburden may improve wound-healing outcomes. - Highlights: • Biological activities of silver nanoparticles for wound-healing purposes • Characterization of the silver nanoparticles impregnated in dressings • Reduction in the P. aeruginosa biofilm formation was statistically significant. • Compatibility to human dermal fibroblasts as the main cell type involved in the reparation • AgNPs covering the surfaces would provide great potential for prevention and treatment

  5. Synthesis, characterization, and antimicrobial properties of copper nanoparticles

    Directory of Open Access Journals (Sweden)

    Usman MS

    2013-11-01

    Full Text Available Muhammad Sani Usman,1 Mohamed Ezzat El Zowalaty,2,5 Kamyar Shameli,1,3 Norhazlin Zainuddin,1 Mohamed Salama,4 Nor Azowa Ibrahim1 1Department of Chemistry, Faculty of Science, 2Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, Universiti Putra Malaysia, Selangor, Malaysia; 3Materials and Energy, Research Center, Karaj, Iran; 4Faculty of Pharmacy, UiTM, Puncak Alam, Selangor, Malaysia; 5Department of Environmental Health, Faculty of Public Health and Tropical Medicine, Jazan University, Jazan, Kingdom of Saudi Arabia Abstract: Copper nanoparticle synthesis has been gaining attention due to its availability. However, factors such as agglomeration and rapid oxidation have made it a difficult research area. In the present work, pure copper nanoparticles were prepared in the presence of a chitosan stabilizer through chemical means. The purity of the nanoparticles was authenticated using different characterization techniques, including ultraviolet visible spectroscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The antibacterial as well as antifungal activity of the nanoparticles were investigated using several microorganisms of interest, including methicillin-resistant Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella choleraesuis, and Candida albicans. The effect of a chitosan medium on growth of the microorganism was studied, and this was found to influence growth rate. The size of the copper nanoparticles obtained was in the range of 2–350 nm, depending on the concentration of the chitosan stabilizer. Keywords: chitosan, copper nanoparticles, antimicrobial activity, chemical synthesis, aqueous medium

  6. The phenotypic evolution of Pseudomonas aeruginosa populations changes in the presence of subinhibitory concentrations of ciprofloxacin

    DEFF Research Database (Denmark)

    Wassermann, Tina; Meinike Jørgensen, Karin; Ivanyshyn, Karolina;

    2016-01-01

    Ciprofloxacin is a widely used antibiotic, in the class of quinolones, for treatment of Pseudomonas aeruginosa infections. The immediate response of P. aeruginosa to subinhibitory concentrations of ciprofloxacin has been investigated previously. However, the long-term phenotypic adaptation, which...

  7. Antimicrobial properties of metal and metal-halide nanoparticles and their potential applications

    Science.gov (United States)

    Torrey, Jason Robert

    Heavy metals, including silver and copper, have been known to possess antimicrobial properties against bacterial, fungal, and viral pathogens. Metal nanoparticles (aggregations of metal atoms 1-200 nm in size) have recently become the subject of intensive study for their increased antimicrobial properties. In the current studies, metal and metal-halide nanoparticles were evaluated for their antibacterial efficacy. Silver (Ag), silver bromide (AgBr), silver iodide (AgI), and copper iodide (CuI) nanoparticles significantly reduced bacterial numbers of the Gram-negative Pseudomonas aeruginosa and the Gram-positive Staphylococcus aureus within 24 hours and were more effective against P. aeruginosa. CuI nanoparticles were found to be highly effective, reducing both organisms by >4.43 log 10 within 15 minutes at 60 ppm Cu. CuI nanoparticles formulated with different stabilizers (sodium dodecyl sulfate, SDS; polyvinyl pyrrolidone, PVP) were further tested against representative Gram-positive and Gram-negative bacteria, Mycobacteria, a fungus (Candida albicans ), and a non-enveloped virus (poliovirus). Both nanoparticles caused significant reductions in most of the Gram-negative bacteria within five minutes (>5.09-log10). The Gram-positive bacterial species and C. albicans were more sensitive to the CuI-SDS than the CuI-PVP nanoparticles. In contrast, the acid-fast Mycobacterium smegmatis was more resistant to CuI-SDS than CuI-PVP nanoparticles. Poliovirus was more resistant than the other organisms tested except for Mycobacterium fortuitum, which displayed the greatest resistance to CuI nanoparticles. As an example of a real world antimicrobial application, polymer coatings embedded with various concentrations of CuI nanoparticles were tested for antibacterial efficacy against P. aeruginosa and S. aureus. Polyester-epoxy powder coatings were found to display superior uniformity, stability and antimicrobial properties against both organisms (>4.92 log 10 after six hours at

  8. Analysis of integrons and associated gene cassettes in clinical isolates of multidrug resistant Pseudomonas aeruginosa from Southwest Nigeria

    OpenAIRE

    Odumosu, Bamidele T; Adeniyi, Bolanle A.; Chandra, Ram

    2013-01-01

    Background Multidrug resistant Pseudomonas aeruginosa harbours integrons and other mobile genetic elements such as plasmids and transposons, which easily disseminate antibiotic resistance genes among clinical strains of P. aeruginosa. Methodology Plasmid extraction of 54 clinical isolates of P. aeruginosa was carried out by alkaline lysis method; and plasmid size estimation was done by using E. coli V517 standard plasmid marker. Fifty-four clinical strains of P. aeruginosa were isolated from ...

  9. Positive signature-tagged mutagenesis in Pseudomonas aeruginosa: Tracking patho-adaptive mutations promoting airways chronic infection

    OpenAIRE

    Bianconi, Irene; Milani, Andrea; Cigana, Cristina; Paroni, Moira; Levesque, Roger C.; Bertoni, Giovanni; Bragonzi, Alessandra

    2011-01-01

    The opportunistic pathogen Pseudomonas aeruginosa can establish life-long chronic infections in the airways of cystic fibrosis (CF) patients. Persistent lifestyle is established with P. aeruginosa patho-adaptive variants, which are clonal with the initially-acquired strains. Several reports indicated that P. aeruginosa adapts by loss-of-function mutations which enhance fitness in CF airways and sustain its clonal expansion during chronic infection. To validate this model of P. aeruginosa adap...

  10. Detection of AmpC-β-lactamases producing isolates among carbapenem resistant P. aeruginosa isolated from burn patient.

    OpenAIRE

    Akbar Mirsalehian; Davood Kalantar-Neyestanaki; Keramat Nourijelyani; Kheirollah Asadollahi; Morovat Taherikalani; Mohammad Emaneini; Fereshteh Jabalameli

    2014-01-01

    Background and Objectives Pseudomonas aeruginosa is responsible for devastating nosocomial infections among severely burn patients. Class C of cephalosporinase (AmpC-β-lactamases) is important cause of multiple β-lactam resistance in P. aeruginosa. The aim of this study was to detect the AmpC-β-lactamases producing isolates among carbapenem resistant P. aeruginosa isolated from burn patient. Material and Methods a total of 100 isolates of carbapenem resistant P. aeruginosa isolates from diffe...

  11. Biosynthesis of silver nanoparticles from Tribulus terrestris and its antimicrobial activity: a novel biological approach.

    Science.gov (United States)

    Gopinath, V; MubarakAli, D; Priyadarshini, S; Priyadharsshini, N Meera; Thajuddin, N; Velusamy, P

    2012-08-01

    In the recent decades, increased development of green synthesis of nanoparticles is inevitable because of its incredible applications in all fields of science. There were numerous work have been produced based on the plant and its extract mediated synthesis of nanoparticles, in this present study to explore that the novel approaches for the biosynthesis of silver nanoparticles using plant fruit bodies. The plant, Tribulus terrestris L. fruit bodies are used in this study, where the dried fruit body extract was mixed with silver nitrate in order to synthesis of silver nanoparticles. The active phytochemicals present in the plant were responsible for the quick reduction of silver ion (Ag(+)) to metallic silver nanoparticles (Ag(0)). The reduced silver nanoparticles were characterized by Transmission Electron Microscope (TEM), Atomic Force Microscope (AFM), XRD, FTIR, UV-vis spectroscopy. The spherical shaped silver nanoparticles were observed and it was found to be 16-28 nm range of sizes. The diffraction pattern also confirmed that the higher percentage of silver with fine particles size. The antibacterial property of synthesized nanoparticles was observed by Kirby-Bauer method with clinically isolated multi-drug resistant bacteria such as Streptococcus pyogens, Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis and Staphylococcus aureus. The plant materials mediated synthesis of silver nanoparticles have comparatively rapid and less expensive and wide application to antibacterial therapy in modern medicine. PMID:22521683

  12. Anti-Pseudomonas aeruginosa IgY antibodies augment bacterial clearance in a murine pneumonia model

    DEFF Research Database (Denmark)

    Thomsen, K; Christophersen, L; Bjarnsholt, T;

    2016-01-01

    -P. aeruginosa IgY antibodies on bacterial eradication in a murine pneumonia model. METHODS: P. aeruginosa pneumonia was established in Balb/c mice and the effects of prophylactic IgY administration on lung bacteriology, clinical parameters and subsequent inflammation were compared to controls. RESULTS...

  13. Pseudomonas aeruginosa extracellular products inhibit staphylococcal growth, and disrupt established biofilms produced by Staphylococcus epidermidis

    DEFF Research Database (Denmark)

    Qin, Zhiqiang; Yang, Liang; Qu, Di;

    2009-01-01

    in overnight cultures had no effect on established P. aeruginosa biofilms and planktonic growth. These findings reveal that P. aeruginosa extracellular products are important microbial competition factors that overcome competition with S. epidermidis, and the results may provide clues for the development...

  14. Pseudomonas aeruginosa mutations in lasl and rhll quorum sensing systems result in milder chronic lung infection

    DEFF Research Database (Denmark)

    Wu, H.; Song, Z.J.; Givskov, Michael Christian;

    2001-01-01

    To understand the importance of quorum sensing in chronic Pseudomonas aeruginosa lung infection, the in vivo pathogenic effects of the wild-type P aeruginosa PAO1 and its double mutant, PAO1 lasI rhlI, in which the signal-generating parts of the quorum sensing systems are defective were compared...

  15. 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 f...

  16. 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 is sugg...

  17. Pseudomonas aeruginosa tolerance to tobramycin, hydrogen peroxide and polymorphonuclear leukocytes is quorum-sensing dependent

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, Peter Østrup; Burmølle, Mette; Hentzer, Morten; Haagensen, Janus Anders Juul; Hougen, Hans Petter; Calum, Henrik; Madsen, Kit G; Moser, Claus; Molin, Søren; Høiby, Niels; Givskov, Michael Christian

    The opportunistic human pathogen Pseudomonas aeruginosa is the predominant micro-organism of chronic lung infections in cystic fibrosis (CF) patients. P. aeruginosa colonizes the CF lungs by forming biofilm structures in the alveoli. In the biofilm mode of growth the bacteria are highly tolerant to...

  18. Glutathione exhibits antibacterial activity and increases tetracycline efficacy against Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    ZHANG YaNi; DUAN KangMin

    2009-01-01

    Glutathione (GSH) plays important roles in pulmonary diseases, and inhaled GSH therapy has been used to treat cystic fibrosis (CF) patients in clinical trials. The results in this report revealed that GSH altered the sensitivity of Pseudomonas aeruginosa to different antibiotics through pathways unrelated to the oxidative stress as generally perceived. In addition, GSH and its oxidized form inhibited the growth of P. Aeruginosa.

  19. Mutations in 23S rRNA Confer Resistance against Azithromycin in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Marvig, Rasmus Lykke; Søndergaard, Mette S. R.; Pedersen, Søren Damkiær;

    2012-01-01

    The emergence of antibiotic-resistant Pseudomonas aeruginosa is an important concern in the treatment of long-term airway infections in cystic fibrosis patients. In this study, we report the occurrence of azithromycin resistance among clinical P. aeruginosa DK2 isolates. We demonstrate that...

  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 of the mechani...... mechanisms used by P. aeruginosa to circumvent host defenses and therapeutic intervention strategies is critical for advancing novel treatment strategies....

  1. The periplasmic protein TolB as a potential drug target in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Alessandra Lo Sciuto

    Full Text Available The Gram-negative bacterium Pseudomonas aeruginosa is one of the most dreaded pathogens in the hospital setting, and represents a prototype of multi-drug resistant "superbug" for which effective therapeutic options are very limited. The identification and characterization of new cellular functions that are essential for P. aeruginosa viability and/or virulence could drive the development of anti-Pseudomonas compounds with novel mechanisms of action. In this study we investigated whether TolB, the periplasmic component of the Tol-Pal trans-envelope protein complex of Gram-negative bacteria, represents a potential drug target in P. aeruginosa. By combining conditional mutagenesis with the analysis of specific pathogenicity-related phenotypes, we demonstrated that TolB is essential for P. aeruginosa growth, both in laboratory and clinical strains, and that TolB-depleted P. aeruginosa cells are strongly defective in cell-envelope integrity, resistance to human serum and several antibiotics, as well as in the ability to cause infection and persist in an insect model of P. aeruginosa infection. The essentiality of TolB for P. aeruginosa growth, resistance and pathogenicity highlights the potential of TolB as a novel molecular target for anti-P. aeruginosa drug discovery.

  2. The periplasmic protein TolB as a potential drug target in Pseudomonas aeruginosa.

    Science.gov (United States)

    Lo Sciuto, Alessandra; Fernández-Piñar, Regina; Bertuccini, Lucia; Iosi, Francesca; Superti, Fabiana; Imperi, Francesco

    2014-01-01

    The Gram-negative bacterium Pseudomonas aeruginosa is one of the most dreaded pathogens in the hospital setting, and represents a prototype of multi-drug resistant "superbug" for which effective therapeutic options are very limited. The identification and characterization of new cellular functions that are essential for P. aeruginosa viability and/or virulence could drive the development of anti-Pseudomonas compounds with novel mechanisms of action. In this study we investigated whether TolB, the periplasmic component of the Tol-Pal trans-envelope protein complex of Gram-negative bacteria, represents a potential drug target in P. aeruginosa. By combining conditional mutagenesis with the analysis of specific pathogenicity-related phenotypes, we demonstrated that TolB is essential for P. aeruginosa growth, both in laboratory and clinical strains, and that TolB-depleted P. aeruginosa cells are strongly defective in cell-envelope integrity, resistance to human serum and several antibiotics, as well as in the ability to cause infection and persist in an insect model of P. aeruginosa infection. The essentiality of TolB for P. aeruginosa growth, resistance and pathogenicity highlights the potential of TolB as a novel molecular target for anti-P. aeruginosa drug discovery. PMID:25093328

  3. Pseudomonas aeruginosa biofilms in the respiratory tract of cystic fibrosis patients

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, Peter Østrup; Fiandaca, Mark J; Pedersen, Jette; Hansen, Christine Rønne; Andersen, Claus Bøgelund; Pressler, Tacjana; Givskov, Michael; Høiby, Niels

    2009-01-01

    The present study was undertaken to investigate the appearance and location of Pseudomonas aeruginosa in the cystic fibrosis (CF) lung and in sputum. Samples include preserved tissues of CF patients who died due to chronic P. aeruginosa lung infection prior to the advent of intensive antibiotic...

  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; Bangsborg, Jette Marie; Hansen, A; Koch, C; Fiehn, N E; Høiby, N

    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...

  5. Effects of Microcystis aeruginosa on life history of water flea Daphnia magna

    Science.gov (United States)

    Liu, Liping; Li, Kang; Chen, Taoying; Dai, Xilin; Jiang, Min; Diana, James S.

    2011-07-01

    Cyanobacterial blooms in eutrophic freshwater systems are a worldwide problem, creating adverse effects for many aquatic organisms by producing toxic microcystins and deteriorating water quality. In this study, microcystins (MCs) in Microcystis aeruginosa, and Daphnia magna exposed to M. aeruginosa, were analyzed by HPLC-MS, and the effects of M. aeruginosa on D. magna were investigated. When D. magna was exposed to M. aeruginosa for more than 2 h, Microcystin-LR (MC-LR) was detected. When exposed to 1.5 × 106, 3 × 106, 0.75 × 107, and 1.5 × 107 cell/mL of M. aeruginosa for 96 h, average survival of D. magna for treatments were 23.33%, 33.33%, 13.33%, 16.67%, respectively, which were significantly lower than the average 100% survival in the control group ( P < 0.05). The adverse effects of M. aeruginosa on body length, time for the first brood, brood numbers, gross fecundity, lifespan, and population growth of D. magna were density-dependent. These results suggest that the occurrence of M. aeruginosa blooms could strongly inhibit the population growth of D. magna through depression of survival, individual growth and gross fecundity. In the most serious situations, M. aeruginosa blooms could undermine the food web by eliminating filter-feeding zooplankton, which would destroy the ecological balance of aquaculture water bodies.

  6. Rhamnolipids Are Virulence Factors That Promote Early Infiltration of Primary Human Airway Epithelia by Pseudomonas aeruginosa

    OpenAIRE

    Zulianello, Laurence; Canard, Coralie; Köhler, Thilo; Caille, Dorothée; Lacroix, Jean-Silvain; Meda, Paolo

    2006-01-01

    The opportunistic bacterium Pseudomonas aeruginosa causes chronic respiratory infections in cystic fibrosis and immunocompromised individuals. Bacterial adherence to the basolateral domain of the host cells and internalization are thought to participate in P. aeruginosa pathogenicity. However, the mechanism by which the pathogen initially modulates the paracellular permeability of polarized respiratory epithelia remains to be understood. To investigate this mechanism, we have searched for vir...

  7. 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.

  8. 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.

  9. Epistatic Mutations And Unpredictable Phenotypes In Pseudomonas Aeruginosa

    DEFF Research Database (Denmark)

    Andresen, Eva Kammer; Abou Hachem, Maher; Jelsbak, Lars

    2015-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen, able to adapt to stressful environments such as the cystic fibrosis (CF) airways. Adaptation of P. aeruginosa to the CF environment is associated with phenotypic changes, such as switch in mucoidy, antibiotic resistance and loss of virulence...

  10. Network-assisted investigation of virulence and antibiotic-resistance systems in Pseudomonas aeruginosa

    Science.gov (United States)

    Hwang, Sohyun; Kim, Chan Yeong; Ji, Sun-Gou; Go, Junhyeok; Kim, Hanhae; Yang, Sunmo; Kim, Hye Jin; Cho, Ara; Yoon, Sang Sun; Lee, Insuk

    2016-05-01

    Pseudomonas aeruginosa is a Gram-negative bacterium of clinical significance. Although the genome of PAO1, a prototype strain of P. aeruginosa, has been extensively studied, approximately one-third of the functional genome remains unknown. With the emergence of antibiotic-resistant strains of P. aeruginosa, there is an urgent need to develop novel antibiotic and anti-virulence strategies, which may be facilitated by an approach that explores P. aeruginosa gene function in systems-level models. Here, we present a genome-wide functional network of P. aeruginosa genes, PseudomonasNet, which covers 98% of the coding genome, and a companion web server to generate functional hypotheses using various network-search algorithms. We demonstrate that PseudomonasNet-assisted predictions can effectively identify novel genes involved in virulence and antibiotic resistance. Moreover, an antibiotic-resistance network based on PseudomonasNet reveals that P. aeruginosa has common modular genetic organisations that confer increased or decreased resistance to diverse antibiotics, which accounts for the pervasiveness of cross-resistance across multiple drugs. The same network also suggests that P. aeruginosa has developed mechanism of trade-off in resistance across drugs by altering genetic interactions. Taken together, these results clearly demonstrate the usefulness of a genome-scale functional network to investigate pathogenic systems in P. aeruginosa.

  11. Genome‐wide identification of novel small RNAs in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Gómez Lozano, María; Marvig, Rasmus Lykke; Molin, Søren;

    2012-01-01

    44 sRNAs in the opportunistic human pathogen Pseudomonas aeruginosa. In this work, RNA sequencing (RNA‐seq) is used to identify novel transcripts in P. aeruginosa involving a combination of three different sequencing libraries. Almost all known sRNAs and over 500 novel intergenic sRNAs are identified...

  12. 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 in...

  13. Multiple roles of biosurfactants in structural biofilm development by Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Pamp, Sünje Johanna; Tolker-Nielsen, Tim

    2007-01-01

    . aeruginosa rhl4 mutants were defective in migration-dependent development of mushroom-shaped multicellular structures in the later phase of biofilm formation. Experiments involving three-color-coded mixed-strain P. aeruginosa biofilms demonstrated that the wild-type and rhl4 and pil4 mutant strains formed...

  14. Distinct roles of extracellular polymeric substances in Pseudomonas aeruginosa biofilm development

    DEFF Research Database (Denmark)

    Yang, Liang; Hu, Yifan; Liu, Yang;

    2011-01-01

    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...

  15. Effects of sulfate on microcystin production, photosynthesis, and oxidative stress in Microcystis aeruginosa.

    Science.gov (United States)

    Chen, Lei; Gin, Karina Y H; He, Yiliang

    2016-02-01

    Increasing sulfate in freshwater systems, caused by human activities and climate change, may have negative effects on aquatic organisms. Microcystis aeruginosa (M. aeruginosa) is both a major primary producer and a common toxic cyanobacterium, playing an important role in the aquatic environment. This study first investigated the effects of sulfate on M. aeruginosa. The experiment presented here aims at analyzing the effects of sulfate on physiological indices, molecular levels, and its influencing mechanism. The results of our experiment showed that sulfate (at 40, 80, and 300 mg L(-1)) inhibited M. aeruginosa growth, increased both intracellular and extracellular toxin contents, and enhanced the mcyD transcript level. Sulfate inhibited the photosynthesis of M. aeruginosa, based on the decrease in pigment content and the down-regulation of photosynthesis-related genes after sulfate exposure. Furthermore, sulfate decreased the maximum electron transport rate, causing the cell to accumulate surplus electrons and form reactive oxygen species (ROS). Sulfate also increased the malondialdehyde (MDA) content, which showed that sulfate damaged the cytomembrane. This damage contributed to the release of intracellular toxin to the culture medium. Although sulfate increased superoxide dismutase (SOD) activities, expression of sod, and total antioxidant capacity in M. aeruginosa, it still overwhelmed the antioxidant system since the ROS level simultaneously increased, and finally caused oxidative stress. Our results indicate that sulfate has direct effects on M. aeruginosa, inhibits photosynthesis, causes oxidative stress, increases toxin production, and affects the related genes expression in M. aeruginosa. PMID:26490939

  16. Draft Genome Sequence of Beneficial Rice Rhizosphere Isolate Pseudomonas aeruginosa PUPa3

    OpenAIRE

    Uzelac, Gordana; Bertani, Iris; Kojic, Milan; Konrad H Paszkiewicz; Studholme, David J.; Passos da Silva, Daniel; Venturi, Vittorio

    2014-01-01

    Pseudomonas aeruginosa PUPa3 is a rhizosphere-colonizing and plant growth-promoting strain isolated from the rhizosphere of rice. This strain has, however, been shown to be pathogenic in two nonmammalian infection models. Here we report the draft genome sequence of P. aeruginosa PUPa3.

  17. 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

    PAO1 in a simple assay with emphasis on the quorum-sensing (QS)-regulated virulence. The maggots were challenged with GFP-tagged P. aeruginosa wild-type (WT) PAO1 and a GFP-tagged P. aeruginosa DeltalasR rhlR (DeltaRR) QS-deficient mutant in different concentrations. Maggots were killed in the...

  18. Paerucumarin, a new metabolite produced by the pvc gene cluster from Pseudomonas aeruginosa.

    Science.gov (United States)

    Clarke-Pearson, Michael F; Brady, Sean F

    2008-10-01

    The pvc gene cluster from Pseudomonas aeruginosa has been linked to the biosynthesis of both the pyoverdine chromophore and pseudoverdine. Our reinvestigation of the role this gene cluster plays in P. aeruginosa secondary metabolite biosynthesis shows that its major product is actually paerucumarin, a novel isonitrile functionalized cumarin. PMID:18689486

  19. Pseudomonas aeruginosa and Its Bacterial Components Influence the Cytokine Response in Thymocytes and Splenocytes.

    Science.gov (United States)

    Weber, Andreas; Zimmermann, Corinna; Mausberg, Anne K; Dehmel, Thomas; Kieseier, Bernd C; Hartung, Hans-Peter; Hofstetter, Harald H

    2016-05-01

    Infections with Pseudomonas aeruginosa may cause many different diseases. The spectrum of such infections in general includes inflammation and bacterial sepsis. Hospital-acquired pneumonia, naturally resistant to a wide range of antibiotics, is associated with a particularly high mortality rate in mechanically ventilated patients. The pathogenesis of P. aeruginosa is complex and mediated by several virulence factors, as well as cell-associated factors. We have previously demonstrated that stimulation with different bacteria triggers the cytokine response of thymocytes. In this study, we investigated the effect of P. aeruginosa and its different components on the cytokine production of immature and mature immune cells. We found that the induced cytokine pattern in the thymus and the spleen after infections with P. aeruginosa is primarily mediated by lipopolysaccharide (LPS) of the outer cell membrane, but other components of the bacterium can influence the cytokine secretion as well. Stimulation with heat-killed P. aeruginosa and LPS does not influence the amount of cytokine-producing CD4(+) T cells but instead suppresses the emergence of Th17 cells. However, stimulation with P. aeruginosa or its components triggers the interleukin-17 (IL-17) response both in thymocytes and in splenocytes. We conclude that infections with P. aeruginosa affect the cytokine secretion of immature and mature cells and that IL-17 and Th17 cells play only a minor role in the development of pathological systemic inflammatory disease conditions during P. aeruginosa infections. Therefore, other inflammatory immune responses must be responsible for septic reactions of the host. PMID:26902726

  20. Heterogeneity of biofilms formed by nonmucoid Pseudomonas aeruginosa isolates from patients with cystic fibrosis

    DEFF Research Database (Denmark)

    Lee, Baoleri; Haagensen, Janus Anders Juul; Ciofu, O.; Andersen, Jens Bo; Hoiby, N.; Molin, Søren

    2005-01-01

    Biofilms are thought to play a key role in the occurrence of lung infections by Pseudomonas aeruginosa in patients with cystic fibrosis (CF). In this study, 20 nonmucoid P. aeruginosa isolates collected during different periods of chronic infection from eight CF patients were assessed with respect...

  1. 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.

  2. Antibiofilm activities of certain biocides in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    S Gharavi

    2009-12-01

    Full Text Available Background and objectives: Pseudomonas aeruginosa is an opportunistic pathogen that can produce biofilm. Biofilm is a complex, three dimensional structure in which microorganisms are attached to a surface and embedded in a matrix made of extracellular polymers. Due to high resistance to antimicrobial agents, biofilms create difficulties in various situations in healthcare. In this study, antibiofilm activities of some biocides in P. aeruginosa were studied."nMaterials and methods: The biofilm production ability of P. aeruginosa strain 214 (a clinical isolate was determined in the presence of six biocides including of ethylene diamine tetra acetic acid (EDTA, silver nitrate (AgNO3, bismuth ethanedithiol (BisEDT, bismuth dimercaprol (BisBAL, bismuth-2-mercaptoethanol (BisMEO and bismuth propanedithiol (BisPDT using the modified microtiter plate method. Bactericidal activity of the biocides against biofilm and planktonic cells was investigated. In this study, permeation of biocides through alginate layer was evaluated with a sandwich cup method."nResults: The results demonstrated that in the presence of bismuth thiols, biofilm production in MIC and sub MIC concentrations was considerably inhibited. Bismuththiols had lower antibiofilm bactericidal activity than EDTA and silver nitrate. One possible mechanism of biofilm resistance is exopolysaccharide production which prevents the access of antimicrobial agents to cells inside the biofilm. Bismuth thiols could not penetrate, while EDTA and silver nitrate had high penetration rate."nConclusions: Due to the frequent use of silver nitrate and EDTA in various applications, low efficacy in the inhibition of biofilm production, unstudied toxicity of BTs for humans and high efficacy in the inhibition of biofilm production, it is suggested that combinatory effect of BTs with silver nitrate or EDTA on biofilms and biofilm production be investigated.

  3. 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.

  4. Ginseng treatment reduces bacterial load and lung pathology in chronic Pseudomonas aeruginosa pneumonia in rats

    DEFF Research Database (Denmark)

    Song, Z; Johansen, H K; Faber, V;

    1997-01-01

    The predominant pathogen in patients with cystic fibrosis (CF) is Pseudomonas aeruginosa, which results in a chronic lung infection associated with progressive pulmonary insufficiency. In a rat model of chronic P. aeruginosa pneumonia mimicking that in patients with CF, we studied whether the...... inflammation and antibody responses could be changed by treatment with the Chinese herbal medicine ginseng. An aqueous extract of ginseng was injected subcutaneously, and cortisone and saline were used as controls. Two weeks after challenge with P. aeruginosa, the ginseng-treated group showed a significantly...... against P. aeruginosa sonicate and a shift from an acute type to a chronic type of lung inflammation compared to those in the control and cortisone-treated groups were observed. These findings indicate that ginseng treatment of an experimental P. aeruginosa pneumonia in rats promotes a cellular response...

  5. Dynamics and spatial distribution of beta-lactamase expression in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Bagge, N.; Hentzer, Morten; Andersen, Jens Bo; Ciofu, O.; Givskov, Michael Christian; Høiby, N.

    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...... cells growing in biofilms. Several genes have been shown to influence the level of ampC expression, but little is known about the regulation of ampC expression in P. aeruginosa biofilms. To study the expression of ampC in P. aeruginosa biofilms, we constructed a reporter that consisted of the fusion 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...

  6. Pattern differentiation in co-culture biofilms formed by Staphylococcus aureus and Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Yang, Liang; Liu, Yang; Markussen, Trine;

    2011-01-01

    -culture biofilms. By growing co-culture biofilms of S. aureus with P. aeruginosa mutants in a flow-chamber system and observing them using confocal laser scanning microscopy, we show that wild-type P. aeruginosa PAO1 facilitates S. aureus microcolony formation. In contrast, P. aeruginosa mucA and rpoN mutants do...... not facilitate S. aureus microcolony formation and tend to outcompete S. aureus in co-culture biofilms. Further investigations reveal that extracellular DNA (eDNA) plays an important role in S. aureus microcolony formation and that P. aeruginosa type IV pili are required for this process, probably through...... their ability to bind to eDNA. Furthermore, P. aeruginosa is able to protect S. aureus against Dictyostelium discoideum phagocytosis in co-culture biofilms....

  7. 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.

  8. Controlled synthesis of Ag nanoparticles with different morphologies and their antibacterial properties

    International Nuclear Information System (INIS)

    In this paper, Ag triangle nanoplates and nanospheres were synthesized by liquid chemical reduction method in the presence of seeds, with L-ascorbic acid as the reductant and polyvinyl pyrrolidone (PVP) as the surface modification agent, respectively. Characterizations of the particles were conducted by various techniques such as X-ray powder diffraction, transmission electron microscopy, ultraviolet–visible absorption spectroscopy, Fourier transformation infrared spectrometry, and thermal analysis. The antibacterial properties of Ag nanoparticles against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa were investigated by disk diffusion and broth dilution methods. The results indicate that Ag nanospheres exhibit better antibacterial properties than that of triangle nanoplates. - Highlights: ► Ag nanoparticles with various morphologies were synthesized by reduction method. ► The aging time plays an important role in controlling the morphology. ► The PVP modified Ag nanoparticles have an excellent water dispersibility. ► The as-synthesized Ag nanoparticles exhibit excellent antibacterial properties.

  9. Controlled green synthesis of silver nanoparticles by Allium cepa and Musa acuminata with strong antimicrobial activity

    Science.gov (United States)

    Sahni, Geetika; Panwar, Amit; Kaur, Balpreet

    2015-02-01

    A controlled "green synthesis" approach to synthesize silver nanoparticles by Allium cepa and Musa acuminata plant extract has been reported. The effect of different process parameters, such as pH, temperature and time, on synthesis of Ag nanoparticles from plant extracts has been highlighted. The work reports an easy approach to control the kinetics of interaction of metal ions with reducing agents, stabilized by ammonia to achieve sub-10 nm particles with narrow size distribution. The nanoparticles have been characterized by UV-Visible spectra and TEM analysis. Excellent antimicrobial activity at extremely low concentration of the nanoparticles was observed against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Fusarium oxysporum which may allow their exploitation as a new generation nanoproduct in biomedical and agricultural applications.

  10. Analytical detection and biological assay of antileukemic drug using gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Selvaraj, V. [Department of Chemical Engineering, Alagappa College of Technology, Anna University, Chennai 600025 (India)]. E-mail: rajselva_77@yahoo.co.in; Alagar, M. [Department of Chemical Engineering, Alagappa College of Technology, Anna University, Chennai 600025 (India)]. E-mail: mkalagar@yahoo.com; Hamerton, I. [Chemistry Division, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2006-11-12

    Gold nanoparticles are reported and evaluated as probes for the detection of anticancer drug 6-mercaptopurine (6-MP). The nature of binding between 6-MP and the gold nanoparticles via complexation is investigated using ultraviolet-visible spectrum, cyclic voltammetry, transmission electron microscopy, fluorescence and Fourier transform infrared (FT-IR) spectroscopy. The bound antileukemic drug is fluorescent and the quenching property of gold nanoparticles could be exploited for biological investigations. The 6-MP-colloidal gold complex is observed to have appreciable antibacterial and antifungal activity against Micrococcus luteus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Aspergillus fumigatus, and Aspergillus niger. The experimental studies suggest that gold nanoparticles have the potential to be used as effective carriers for anticancer drugs.

  11. The combined effects of Aloe vera gel and silver nanoparticles on wound healing in rats

    Directory of Open Access Journals (Sweden)

    Y. Yousefpoor

    2016-01-01

    Full Text Available Objective(s: This study was aimed at investigating the synergy effects of Aloe vera gel and silver nanoparticles on the healing rate of the cutting wounds. Materials and Methods: In order to determine the concentration of silver nanoparticles in Aloe vera gel, the MBC methods were applied on the most common bacteria infecting wounds, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa. The cutting wounds with Full-thickness skin were dorsally created on rats; then the rats were divided into 4 groups. The treatments groups included: mixture of Aloe vera gel and silver nanoparticles, Aloe vera gel alone and silver nanoparticles alone in addition to control groups. The treatment was carried out for 2 weeks and the size of the wound closures were measured by an image software analysis. Results:There was no significant difference (p

  12. [Surviving Forms in Antibiotic-Treated Pseudomonas aeruginosa].

    Science.gov (United States)

    Mulyukin, A L; Kozlova, A N; Sorokin, V V; Suzina, N E; Cherdyntseva, T A; Kotova, I B; Gaponov, A M; Tutel'yan, A V; El'-Registan, G I

    2015-01-01

    Survival of bacterial populations treated with lethal doses of antibiotics is ensured by the presence of very small numbers of persister cells. Unlike antibiotic-resistant cells, antibiotic tolerance of persisters is not inheritable and reversible. The present work provides evidence supporting the hypothesis of transformation (maturation) of persisters of an opportunistic pathogen Pseudomonas aeruginosa revealed by ciprofloxacin (CF) treatment (25-100 μg/mL) into dormant cystlike cells (CLC) and non-culturable cells (NC), as was described previously for a number. of non-spore-forming bacteria. Subpopulations of type 1 and type 2 persisters, which survived antibiotic treatment and developed into dormant forms, were heterogeneous in their capacity to form colonies or microcolonies upon germination, in resistance to heating at 70 degrees C, and in cell morphology Type 1 persisters, which were formed after 1-month incubation in the stationary-phase cultures in the medium with decreased C and N concentrations, developed in several types of surviving cells, including those similar to CLC in cell morphology. In the course of 1-month incubation of type 2 persisters, which were formed in exponentially growing cultures, other types of surviving cells developed: immature CLC and L-forms. Unlike P. aeruginosa CLC formed in the control post-stationary phase cultures without antibiotic treatment, most of 1-month persisters, especially type 2 ones, were characterized by the loss of colony-forming capacity, probably due to transition into an uncultured state with relatively high numbers of live intact cells (Live/Dead test). Another survival strategy of P. aeruginosa populations was ensured by a minor subpopulation of CF-tolerant and CF-resistant cells able to grow in the form of microcolonies or regular colonies of decreased size in the presence of the antibiotic. The described P. aeruginosa dormant forms may be responsible for persistent forms in bacteria carriers and latent

  13. Protective role of murine norovirus against Pseudomonas aeruginosa acute pneumonia.

    Science.gov (United States)

    Thépaut, Marion; Grandjean, Teddy; Hober, Didier; Lobert, Pierre-Emmanuel; Bortolotti, Perrine; Faure, Karine; Dessein, Rodrigue; Kipnis, Eric; Guery, Benoit

    2015-01-01

    The murine norovirus (MNV) is a recently discovered mouse pathogen, representing the most common contaminant in laboratory mouse colonies. Nevertheless, the effects of MNV infection on biomedical research are still unclear. We tested the hypothesis that MNV infection could alter immune response in mice with acute lung infection. Here we report that co-infection with MNV increases survival of mice with Pseudomonas aeruginosa acute lung injury and decreases in vivo production of pro-inflammatory cytokines. Our results suggest that MNV infection can deeply modify the parameters studied in conventional models of infection and lead to false conclusions in experimental models. PMID:26338794

  14. Functional analysis of the Pseudomonas aeruginosa autoinducer PAI.

    OpenAIRE

    Passador, L; Tucker, K D; Guertin, K R; Journet, M P; Kende, A S; Iglewski, B H

    1996-01-01

    A series of structural analogs of the Pseudomonas aeruginosa autoinducer [PAI, N-3-oxo-dodecanoyl homoserine lactone] were obtained and tested for their ability to act as autoinducers in stimulating the expression of the gene for elastase (lasB) by measuring beta-galactosidase production from a lasB-lacZ gene fusion in the presence of the transcriptional activator LasR. The data suggest that the length of the acyl side chain of the autoinducer molecule is the most critical factor for activity...

  15. Nanoindentation of Pseudomonas aeruginosa bacterial biofilm using atomic force microscopy

    Science.gov (United States)

    Baniasadi, Mahmoud; Xu, Zhe; Gandee, Leah; Du, Yingjie; Lu, Hongbing; Zimmern, Philippe; Minary-Jolandan, Majid

    2014-12-01

    Bacterial biofilms are a source of many chronic infections. Biofilms and their inherent resistance to antibiotics are attributable to a range of health issues including affecting prosthetic implants, hospital-acquired infections, and wound infection. Mechanical properties of biofilm, in particular, at micro- and nano-scales, are governed by microstructures and porosity of the biofilm, which in turn may contribute to their inherent antibiotic resistance. We utilize atomic force microscopy (AFM)-based nanoindentation and finite element simulation to investigate the nanoscale mechanical properties of Pseudomonas aeruginosa bacterial biofilm. This biofilm was derived from human samples and represents a medically relevant model.

  16. Genetic studies of the murine corneal response to Pseudomonas aeruginosa.

    OpenAIRE

    Berk, R S; Beisel, K; Hazlett, L D

    1981-01-01

    The murine genetic control of resistance to Pseudomonas aeruginosa eye infection previously has been demonstrated to be regulated by two complementing dominant genes, PsCR1 and PsCR2. The PsCR1 locus apparently is not associated with the H-2 complex, whereas the PsCR2 locus could not definitively be associated with H-2. In this study we attempted to demonstrate a possible H-2 linkage of the PsCR2 locus. A panel of inbred congenic strains varying with either the H-2 haplotype or genetic backgr...

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

    OpenAIRE

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

    2013-01-01

    Background The elucidation of the routes of transmission of a pathogen is crucial for the prevention of infectious diseases caused by bacteria that are not a resident in human tissue. 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). Case presentation A 38-year-old man, who had undergone surgery for glaucoma 2 years ago previously, pres...

  18. Biosurfactant Production by Pseudomonas aeruginosa from Renewable Resources

    OpenAIRE

    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...

  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. Nanoindentation of Pseudomonas aeruginosa bacterial biofilm using atomic force microscopy

    International Nuclear Information System (INIS)

    Bacterial biofilms are a source of many chronic infections. Biofilms and their inherent resistance to antibiotics are attributable to a range of health issues including affecting prosthetic implants, hospital-acquired infections, and wound infection. Mechanical properties of biofilm, in particular, at micro- and nano-scales, are governed by microstructures and porosity of the biofilm, which in turn may contribute to their inherent antibiotic resistance. We utilize atomic force microscopy (AFM)-based nanoindentation and finite element simulation to investigate the nanoscale mechanical properties of Pseudomonas aeruginosa bacterial biofilm. This biofilm was derived from human samples and represents a medically relevant model. (paper)

  1. Electron Flow through Nitrotyrosinate in Pseudomonas aeruginosa Azurin

    OpenAIRE

    Warren, Jeffrey J.; Herrera, Nadia; Hill, Michael G.; Winkler, Jay R.; Gray, Harry B.

    2013-01-01

    We have designed ruthenium-modified Pseudomonas aeruginosa azurins that incorporate 3-nitrotyrosine (NO_(2)YOH) between Ru(2,2′-bipyridine)_2(imidazole)(histidine) and Cu redox centers in electron transfer (ET) pathways. We investigated the structures and reactivities of three different systems: RuH107NO_(2)YOH109, RuH124NO_(2)YOH122, and RuH126NO_(2)YOH122. RuH107NO_(2)YOH109, unlabeled H124NO_(2)YOH122, and unlabeled H126NO_(2)YOH122 were structurally characterized. The pKa’s of NO_(2)YOH a...

  2. Antibiotic resistance in clinical isolates of Pseudomonas aeruginosa in Jamaica Resistencia a antibióticos en cepas clínicas de Pseudomonas aeruginosa en Jamaica

    OpenAIRE

    Brown, Paul D.; Anicetus Izundu

    2004-01-01

    OBJECTIVE: To assess antibiotic resistance in clinical isolates of Pseudomonas aeruginosa in Jamaica, and to obtain baseline information on the presence of this important pathogen. METHODS: A total of 51 isolates of Pseudomonas aeruginosa, obtained from 162 clinical specimens from major hospitals and laboratories in seven parishes in Jamaica, were analyzed between May and August 2002. Isolates were tested against 18 different antibiotics by a disk diffusion method. RESULTS: Organisms were cul...

  3. Cystic fibrosis-niche adaptation of Pseudomonas aeruginosa reduces virulence in multiple infection hosts.

    Science.gov (United States)

    Lorè, Nicola Ivan; Cigana, Cristina; De Fino, Ida; Riva, Camilla; Juhas, Mario; Schwager, Stephan; Eberl, Leo; Bragonzi, Alessandra

    2012-01-01

    The opportunistic pathogen Pseudomonas aeruginosa is able to thrive in diverse ecological niches and to cause serious human infection. P. aeruginosa environmental strains are producing various virulence factors that are required for establishing acute infections in several host organisms; however, the P. aeruginosa phenotypic variants favour long-term persistence in the cystic fibrosis (CF) airways. Whether P. aeruginosa strains, which have adapted to the CF-niche, have lost their competitive fitness in the other environment remains to be investigated. In this paper, three P. aeruginosa clonal lineages, including early strains isolated at the onset of infection, and late strains, isolated after several years of chronic lung infection from patients with CF, were analysed in multi-host model systems of acute infection. P. aeruginosa early isolates caused lethality in the three non-mammalian hosts, namely Caenorhabditis elegans, Galleria mellonella, and Drosophila melanogaster, while late adapted clonal isolates were attenuated in acute virulence. When two different mouse genetic background strains, namely C57Bl/6NCrl and Balb/cAnNCrl, were used as acute infection models, early P. aeruginosa CF isolates were lethal, while late isolates exhibited reduced or abolished acute virulence. Severe histopathological lesions, including high leukocytes recruitment and bacterial load, were detected in the lungs of mice infected with P. aeruginosa CF early isolates, while late isolates were progressively cleared. In addition, systemic bacterial spread and invasion of epithelial cells, which were detected for P. aeruginosa CF early strains, were not observed with late strains. Our findings indicate that niche-specific selection in P. aeruginosa reduced its ability to cause acute infections across a broad range of hosts while maintaining the capacity for chronic infection in the CF host. PMID:22558188

  4. Cystic fibrosis-niche adaptation of Pseudomonas aeruginosa reduces virulence in multiple infection hosts.

    Directory of Open Access Journals (Sweden)

    Nicola Ivan Lorè

    Full Text Available The opportunistic pathogen Pseudomonas aeruginosa is able to thrive in diverse ecological niches and to cause serious human infection. P. aeruginosa environmental strains are producing various virulence factors that are required for establishing acute infections in several host organisms; however, the P. aeruginosa phenotypic variants favour long-term persistence in the cystic fibrosis (CF airways. Whether P. aeruginosa strains, which have adapted to the CF-niche, have lost their competitive fitness in the other environment remains to be investigated. In this paper, three P. aeruginosa clonal lineages, including early strains isolated at the onset of infection, and late strains, isolated after several years of chronic lung infection from patients with CF, were analysed in multi-host model systems of acute infection. P. aeruginosa early isolates caused lethality in the three non-mammalian hosts, namely Caenorhabditis elegans, Galleria mellonella, and Drosophila melanogaster, while late adapted clonal isolates were attenuated in acute virulence. When two different mouse genetic background strains, namely C57Bl/6NCrl and Balb/cAnNCrl, were used as acute infection models, early P. aeruginosa CF isolates were lethal, while late isolates exhibited reduced or abolished acute virulence. Severe histopathological lesions, including high leukocytes recruitment and bacterial load, were detected in the lungs of mice infected with P. aeruginosa CF early isolates, while late isolates were progressively cleared. In addition, systemic bacterial spread and invasion of epithelial cells, which were detected for P. aeruginosa CF early strains, were not observed with late strains. Our findings indicate that niche-specific selection in P. aeruginosa reduced its ability to cause acute infections across a broad range of hosts while maintaining the capacity for chronic infection in the CF host.

  5. Synthesis and Characterization of BSA Conjugated Silver Nanoparticles (Ag/BSA Nanoparticles) and Evaluation of Biological Properties of Ag/BSA Nanoparticles and Ag/BSA Nanoparticles Loaded Poly(hydroxy butyrate valerate) PHBV Films

    Science.gov (United States)

    Ambaye, Almaz

    Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa are the etiological agents of several infectious diseases. Antibiotic resistance by these three microbes has emerged as a prevalent problem due in part to the misuse of existing antibiotics and the lack of novel antibiotics. Nanoparticles have emerged as an alternative antibacterial agents to conventional antibiotics owing to their high surface area to volume ratio and their unique chemical and physical properties. Among the nanoparticles, silver nanoparticles have gained increasing attention because silver nanoparticles exhibit antibacterial activity against a range of gram positive and gram negative bacteria. Nanoparticles of well-defined chemistry and morphology can be used in broad biomedical applications, especially in bone tissue engineering applications, where bone infection by bacteria can be acute and lethal. It is commonly noted in the literature that the activity of nanoparticles against microorganisms is dependent upon the size and concentration of the nanoparticles as well as the chemistry of stabilizing agent. To the best of our knowledge, a comprehensive study that evaluates the antibacterial activity of well characterized silver nanoparticles in particular Bovine Serum Albumin (BSA) stabilized against S. aureus and E. coli and cytotoxicity level of BSA stabilized silver nanoparticles towards osteoblast cells (MC3T3-E1) is currently lacking. Therefore, the primary objective of this study was to characterize protein conjugated silver nanoparticles prepared by chemical reduction of AgNO3 and BSA mixture. The formation of Ag/BSA nanoparticles was studied by UV-Vis spectroscopy. The molar ratio of silver to BSA in the Ag/BSA nanoparticles was established to be 27+/- 3: 1, based on Thermogravimetric Analysis and Atomic Absorption Spectroscopy. Based on atomic force microscopy, dynamic light scattering,and transmission electron microscopy(TEM) measurements, the particle size (diameter) of

  6. Inhibition of bacterial growth by iron oxide nanoparticles with and without attached drug: Have we conquered the antibiotic resistance problem?

    Science.gov (United States)

    Armijo, Leisha M.; Jain, Priyanka; Malagodi, Angelina; Fornelli, F. Zuly; Hayat, Allison; Rivera, Antonio C.; French, Michael; Smyth, Hugh D. C.; Osiński, Marek

    2015-03-01

    Pseudomonas aeruginosa is among the top three leading causative opportunistic human pathogens, possessing one of the largest bacterial genomes and an exceptionally large proportion of regulatory genes therein. It has been known for more than a decade that the size and complexity of the P. aeruginosa genome is responsible for the adaptability and resilience of the bacteria to include its ability to resist many disinfectants and antibiotics. We have investigated the susceptibility of P. aeruginosa bacterial biofilms to iron oxide (magnetite) nanoparticles (NPs) with and without attached drug (tobramycin). We also characterized the susceptibility of zero-valent iron NPs, which are known to inactivate microbes. The particles, having an average diameter of 16 nm were capped with natural alginate, thus doubling the hydrodynamic size. Nanoparticle-drug conjugates were produced via cross-linking drug and alginate functional groups. Drug conjugates were investigated in the interest of determining dosage, during these dosage-curve experiments, NPs unbound to drug were tested in cultures as a negative control. Surprisingly, we found that the iron oxide NPs inhibited bacterial growth, and thus, biofilm formation without the addition of antibiotic drug. The inhibitory dosages of iron oxide NPs were investigated and the minimum inhibitory concentrations are presented. These findings suggest that NP-drug conjugates may overcome the antibiotic drug resistance common in P. aeruginosa infections.

  7. Silver nanoparticle containing silk fibroin bionanotextiles

    Energy Technology Data Exchange (ETDEWEB)

    Calamak, Semih; Aksoy, Eda Ayse [Hacettepe University, Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy (Turkey); Erdogdu, Ceren; Sagıroglu, Meral [Hacettepe University, Department of Pharmaceutical Microbiology, Faculty of Pharmacy (Turkey); Ulubayram, Kezban, E-mail: ukezban@hacettepe.edu.tr [Hacettepe University, Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy (Turkey)

    2015-02-15

    Development of new generation bionanotextiles is an important growing field, and they have found applications as wound dressings, bandages, tissue scaffolds, etc. In this study, silver nanoparticle (AgNP) containing silk-based bionanotextiles were fabricated by electrospinning, and processing parameters were optimized and discussed in detail. AgNPs were in situ synthesized within fibroin nanofibers by UV reduction of silver ions to metallic silver. The influence of post-treatments via methanol treatment and glutaraldehyde (GA) vapor exhibited changes in the secondary structure of silk. Methanol treatment increased the tensile properties of fibers due to supported crystalline silk structure, while GA vapor promoted amorphous secondary structure. AgNP containing silk fibroin bionanotextiles had strong antibacterial activity against gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa.

  8. Silver nanoparticle containing silk fibroin bionanotextiles

    International Nuclear Information System (INIS)

    Development of new generation bionanotextiles is an important growing field, and they have found applications as wound dressings, bandages, tissue scaffolds, etc. In this study, silver nanoparticle (AgNP) containing silk-based bionanotextiles were fabricated by electrospinning, and processing parameters were optimized and discussed in detail. AgNPs were in situ synthesized within fibroin nanofibers by UV reduction of silver ions to metallic silver. The influence of post-treatments via methanol treatment and glutaraldehyde (GA) vapor exhibited changes in the secondary structure of silk. Methanol treatment increased the tensile properties of fibers due to supported crystalline silk structure, while GA vapor promoted amorphous secondary structure. AgNP containing silk fibroin bionanotextiles had strong antibacterial activity against gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa

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

    Directory of Open Access Journals (Sweden)

    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.

  10. A green and facile approach for the synthesis of silver nanoparticles using aqueous extract of Ailanthus excelsa leaves, evaluation of its antibacterial and anticancer efficacy

    Indian Academy of Sciences (India)

    V Vinmathi; S Justin Packia Jacob

    2015-06-01

    Silver nanoparticles possess a wide range of applications especially in the field of medicine and this has stimulated the need for synthesizing them. Conventionally, chemical methods are used, which are hazardous and energy consuming. Therefore an eco-friendly and facile means of synthesizing nanoparticles is needed to replace the chemical method of synthesis. In the present study, silver nanoparticles were synthesized in a cost-effective and environment-friendlymanner using aqueous leaf extract of Ailanthus excelsa—a medicinal tree used in the treatment of asthma, bronchitis, cold, abdominal pain, etc. The leaf extract helped in the bioreduction of silver ions yielding silver nanoparticles. The silver nanoparticles thus biosynthesized were characterized using UV–vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR) analysis and scanning electron microscopy (SEM). These biologically synthesized silver nanoparticles were also found to exhibit excellent antibacterial effect against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia and anticancer effect against MCF-7 cell line.

  11. Biopolymeric nanoparticles

    International Nuclear Information System (INIS)

    This review on nanoparticles highlights the various biopolymers (proteins and polysaccharides) which have recently revolutionized the world of biocompatible and degradable natural biological materials. The methods of their fabrication, including emulsification, desolvation, coacervation and electrospray drying are described. The characterization of different parameters for a given nanoparticle, such as particle size, surface charge, morphology, stability, structure, cellular uptake, cytotoxicity, drug loading and drug release, is outlined together with the relevant measurement techniques. Applications in the fields of medicine and biotechnology are discussed along with a promising future scope. (topical review)

  12. Biopolymeric nanoparticles

    Directory of Open Access Journals (Sweden)

    Sushmitha Sundar, Joydip Kundu and Subhas C Kundu

    2010-01-01

    Full Text Available This review on nanoparticles highlights the various biopolymers (proteins and polysaccharides which have recently revolutionized the world of biocompatible and degradable natural biological materials. The methods of their fabrication, including emulsification, desolvation, coacervation and electrospray drying are described. The characterization of different parameters for a given nanoparticle, such as particle size, surface charge, morphology, stability, structure, cellular uptake, cytotoxicity, drug loading and drug release, is outlined together with the relevant measurement techniques. Applications in the fields of medicine and biotechnology are discussed along with a promising future scope.

  13. Rapid Necrotic Killing of Polymorphonuclear Leukocytes Is Caused by Quorum-Sensing-Controlled Production of Rhamnolipid by Pseudomonas Aeruginosa

    DEFF Research Database (Denmark)

    Jensen, P. Ø.; Bjarnsholt, Thomas; Phipps, Richard Kerry;

    2007-01-01

    . aeruginosa induced rapid necrosis of the PMNs. This mechanism was also observed in mouse lungs infected with P. aeruginosa, and in sputum obtained from P.-aeruginosa-infected patients with cystic fibrosis. Evidence is presented that the necrotic effect was caused by rhamnolipids, production of which is QS...... controlled. The results demonstrate the potential of the QS system to facilitate infections with P. aeruginosa by disabling the PMNs, which are a major first line of defence of the host. Furthermore, the study emphasizes the inhibition of QS as a target for the treatment of infections with P. aeruginosa....

  14. Cadmium and Chromium Toxicity to Pseudokirchneriella subcapitata and Microcystis aeruginosa

    Directory of Open Access Journals (Sweden)

    Suzelei Rodgher

    2012-02-01

    Full Text Available The toxicity of cadmium and chromium to Pseudokirchneriella subcapitata and Microcystis aeruginosa was evaluated through algal growth rate during 96h exposure bioassays. Free metal ion concentrations were obtained using MINEQL+ 4.61 and used for IC50 determination. Metal accumulations by the microorganisms were determined and they were found to be dependent on the concentration of Cd2+ and Cr6+. IC50 for P. subcapitata were 0.60 µmol L-1 free Cd2+ and 20 µmol L-1 free Cr6+, while the IC50 values for M. aeruginosa were 0.01 µmol L-1 Cd2+ and 11.07 µmol L-1 Cr6+ . P. subcapitata accumulated higher metal concentrations (0.001 -0.05 µmol Cd mg-1 dry wt. and 0.001 -0.04 µmol Cr mg-1 dry wt than the cyanobacteria (0.001 -0.01 µmol Cd mg-1 dry wt and 0.001 -0.02 µmol Cr mg-1 dry wt. Cadmium was more toxic than chromium to both the microorganisms.

  15. Mechanical Properties of Type IV Pili in P. Aeruginosa

    Science.gov (United States)

    Lu, Shun; Touhami, Ahmed; Scheurwater, Edie; Harvey, Hanjeong; Burrows, Lori; Dutcher, John

    2009-03-01

    Type IV pili (Tfp) are thin flexible protein filaments that extend from the cell membrane of bacteria such as Pseudomonas aeruginosa and Neisseria gonorrhoeae. The mechanical properties of Tfp are of great importance since they allow bacteria to interact with and colonize various surfaces. In the present study, we have used atomic force microscopy (AFM) for both imaging and pulling on Tfp from P. aeruginosa (PAO1) and from its PilA, PilT, and FliC mutants. A single pilus filament was mechanically stretched and the resulting force-extension profiles were fitted using the worm-like-chain (WLC) model. The statistical distributions obtained for contour length, persistence length, and number of pili per bacteria pole, were used to evaluate the mechanical properties of a single pilus and the biogenesis functions of different proteins (PilA, PilT) involved in its assembly and disassembly. Importantly, the persistence length value of ˜ 1 μm measured in the present study, which is consistent with the curvature of the pili observed in our AFM images, is significantly lower than the value of 5 μm reported earlier by Skerker et al. (1). Our results shed new light on the role of mechanical forces that mediate bacteria-surface interactions and biofilm formation. 1- J.M. Skerker and H.C. Berg, Proc. Natl. Acad. Sci. USA, 98, 6901-6904 (2001).

  16. Labeling of pseudomonas aeruginosa with In-111-oxine

    International Nuclear Information System (INIS)

    Labeling of live bacteria with gamma emitting radioisotope provides a useful tool for the experimental in vivo tracking of bacteria in various body organs of animals. The authors labeled a serum resistant strain of Pseudomonas aeruginosa (ATCC number27853) with In-111-oxine. P. aeruginosa streaked heavily on ten blood agar plates, was grown overnight, and suspended in 50 ml of saline using sterile cotton swabs. The suspension was sonicated for 3 minutes at 40 watts with a small probe, 500 μCi of commercially prepared In-111-oxine added and the bacteria incubated at 370C for 2.5 hours. The labeled bacteria were centrifuged and washed once with saline and resuspended to a final volume of 50 ml in saline. The labeled Pseudomonas, 10/sup 9/-10/sup 10/ cfu/ml, retained 120-190 μCi of cell-bound In-111. In vitro studies showed good retention of the In-111 label in saline at 370C (75-85% cell-bound radioactivity at 1 hour) and in canine blood at 370C (30-55% cell-bound radioactivity at 1 hour). The loss of cell-associated radioactivity in blood, with a corresponding decrease in the number of viable organisms, is probably a result of phagocyte-mediated killing of the organisms and subsequent release of the label. The labeled bacteria have been used successfully for sequential imaging in experimental animals to track bacteria injected into blood and the biliary tree

  17. Phage selection restores antibiotic sensitivity in MDR Pseudomonas aeruginosa.

    Science.gov (United States)

    Chan, Benjamin K; Sistrom, Mark; Wertz, John E; Kortright, Kaitlyn E; Narayan, Deepak; Turner, Paul E

    2016-01-01

    Increasing prevalence and severity of multi-drug-resistant (MDR) bacterial infections has necessitated novel antibacterial strategies. Ideally, new approaches would target bacterial pathogens while exerting selection for reduced pathogenesis when these bacteria inevitably evolve resistance to therapeutic intervention. As an example of such a management strategy, we isolated a lytic bacteriophage, OMKO1, (family Myoviridae) of Pseudomonas aeruginosa that utilizes the outer membrane porin M (OprM) of the multidrug efflux systems MexAB and MexXY as a receptor-binding site. Results show that phage selection produces an evolutionary trade-off in MDR P. aeruginosa, whereby the evolution of bacterial resistance to phage attack changes the efflux pump mechanism, causing increased sensitivity to drugs from several antibiotic classes. Although modern phage therapy is still in its infancy, we conclude that phages, such as OMKO1, represent a new approach to phage therapy where bacteriophages exert selection for MDR bacteria to become increasingly sensitive to traditional antibiotics. This approach, using phages as targeted antibacterials, could extend the lifetime of our current antibiotics and potentially reduce the incidence of antibiotic resistant infections. PMID:27225966

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

    Directory of Open Access Journals (Sweden)

    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.

  19. Identification of Pseudomonas aeruginosa genes associated with antibiotic susceptibility

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Pseudomonas aeruginosa causes acute and chronic infections in humans and these infections are difficult to treat due to the bacteria’s high-level of intrinsic and acquired resistance to antibiotics. To address this problem, it is crucial to investigate the molecular mechanisms of antibiotic resistance in this organism. In this study, a P. aeruginosa transposon insertion library of 17000 clones was constructed and screened for altered susceptibility to seven antibiotics. Colonies grown on agar plates con- taining antibiotics at minimum inhibitory concentrations (MICs) and those unable to grow at ? MIC were collected. The transposon-disrupted genes in 43 confirmed mutants that showed at least a three-fold increase or a two-fold decrease in suscep- tibility to at least one antibiotic were determined by semi-random PCR and subsequent sequencing analysis. In addition to nine genes known to be associated with antibiotic resistance, including mexI, mexB and mexR, 24 new antibiotic resis- tance-associated genes were identified, including a fimbrial biogenesis gene pilY1 whose disruption resulted in a 128-fold in- crease in the MIC of carbenicillin. Twelve of the 43 genes identified were of unknown function. These genes could serve as targets to control or reverse antibiotic resistance in this important human pathogen.

  20. 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.

  1. Effect of methylglyoxal on multidrug-resistant Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    KunihikoNishino

    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.

  2. Cystic Fibrosis Transmembrane Conductance Regulator is an Epithelial Cell Receptor for Clearance of Pseudomonas aeruginosa from the Lung

    Science.gov (United States)

    Pier, Gerald B.; Grout, Martha; Zaidi, Tanweer S.

    1997-10-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride ion channel, but its relationship to the primary clinical manifestation of CF, chronic Pseudomonas aeruginosa pulmonary infection, is unclear. We report that CFTR is a cellular receptor for binding, endocytosing, and clearing P. aeruginosa from the normal lung. Murine cells expressing recombinant human wild-type CFTR ingested 30-100 times as many P. aeruginosa as cells lacking CFTR or expressing mutant Δ F508 CFTR protein. Purified CFTR inhibited ingestion of P. aeruginosa by human airway epithelial cells. The first extracellular domain of CFTR specifically bound to P. aeruginosa and a synthetic peptide of this region inhibited P. aeruginosa internalization in vivo, leading to increased bacterial lung burdens. CFTR clears P. aeruginosa from the lung, indicating a direct connection between mutations in CFTR and the clinical consequences of CF.

  3. Antibacterial activity of magnetic iron oxide nanoparticles synthesized by laser ablation in liquid

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Raid A., E-mail: raidismail@yahoo.com [Laser Physics Division, Applied Science Department, University of Technology, Baghdad (Iraq); Sulaiman, Ghassan M. [Biotechnology Division, Applied Science Department, University of Technology, Baghdad (Iraq); Abdulrahman, Safa A. [Laser Physics Division, Applied Science Department, University of Technology, Baghdad (Iraq); Marzoog, Thorria R. [Biotechnology Division, Applied Science Department, University of Technology, Baghdad (Iraq)

    2015-08-01

    In this study, (50–110 nm) magnetic iron oxide (α-Fe{sub 2}O{sub 3}) nanoparticles were synthesized by pulsed laser ablation of iron target in dimethylformamide (DMF) and sodium dodecyl sulfate (SDS) solutions. The structural properties of the synthesized nanoparticles were investigated by using Fourier Transform Infrared (FT-IR) spectroscopy, UV–VIS absorption, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The effect of laser fluence on the characteristics of these nanoparticles was studied. Antibacterial activities of iron oxide nanoparticles were tested against Gram-positive; Staphylococcus aureus and Gram-negative; Escherichia coli, Pseudomonas aeruginosa and Serratia marcescens. The results showed a noteworthy inhibition on both bacterial strains. The preparation conditions were found to affect significantly the antibacterial activity of these nanoparticles. The synthesized magnetic nanoparticles were used to capture rapidly S. aureus bacteria under the magnetic field effect. - Highlights: • Synthesis magnetic iron oxide nanoparticles by pulsed laser ablation • Antibacterial activity against Gram-positive and Gram-negative bacteria • Captured magnetic nanoparticles by S. aureus bacteria under effect of magnetic field.

  4. Interactions between the antimicrobial agent triclosan and the bloom-forming cyanobacteria Microcystis aeruginosa.

    Science.gov (United States)

    Huang, Xiaolong; Tu, Yenan; Song, Chaofeng; Li, Tiancui; Lin, Juan; Wu, Yonghong; Liu, Jiantong; Wu, Chenxi

    2016-03-01

    Cyanobacteria can co-exist in eutrophic waters with chemicals or other substances derived from personal care products discharged in wastewater. In this work, we investigate the interactions between the antimicrobial agent triclosan (TCS) and the bloom-forming cyanobacteria Microcystis aeruginosa. M. aeruginosa was very sensitive to TCS with the 96h lowest observed effect concentration of 1.0 and 10μg/L for inhibition of growth and photosynthetic activity, respectively. Exposure to TCS at environmentally relevant levels (0.1-2.0μg/L) also affected the activities of superoxide dismutase (SOD) and the generation of reduced glutathione (GSH), while microcystin production was not affected. Transmission electron microscope (TEM) examination showed the destruction of M. aeruginosa cell ultrastructure during TCS exposure. TCS however, can be biotransformed by M. aeruginosa with methylation as a major biotransformation pathway. Furthermore, the presence of M. aeruginosa in solution promoted the photodegradation of TCS. Overall, our results demonstrate that M. aeruginosa plays an important role in the dissipation of TCS in aquatic environments but high residual TCS can exert toxic effects on M. aeruginosa. PMID:26800489

  5. Enhanced Clearance of Pseudomonas aeruginosa by Peroxisome Proliferator-Activated Receptor Gamma.

    Science.gov (United States)

    Bedi, Brahmchetna; Yuan, Zhihong; Joo, Myungsoo; Zughaier, Susu M; Goldberg, Joanna B; Arbiser, Jack L; Hart, C Michael; Sadikot, Ruxana T

    2016-07-01

    The pathogenic profile of Pseudomonas aeruginosa is related to its ability to secrete a variety of virulence factors. Quorum sensing (QS) is a mechanism wherein small diffusible molecules, specifically acyl-homoserine lactones, are produced by P. aeruginosa to promote virulence. We show here that macrophage clearance of P. aeruginosa (PAO1) is enhanced by activation of the nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPARγ). Macrophages treated with a PPARγ agonist (pioglitazone) showed enhanced phagocytosis and bacterial killing of PAO1. It is known that PAO1 QS molecules are inactivated by PON-2. QS molecules are also known to inhibit activation of PPARγ by competitively binding PPARγ receptors. In accord with this observation, we found that infection of macrophages with PAO1 inhibited expression of PPARγ and PON-2. Mechanistically, we show that PPARγ induces macrophage paraoxonase 2 (PON-2), an enzyme that degrades QS molecules produced by P. aeruginosa Gene silencing studies confirmed that enhanced clearance of PAO1 in macrophages by PPARγ is PON-2 dependent. Further, we show that PPARγ agonists also enhance clearance of P. aeruginosa from lungs of mice infected with PAO1. Together, these data demonstrate that P. aeruginosa impairs the ability of host cells to mount an immune response by inhibiting PPARγ through secretion of QS molecules. These studies define a novel mechanism by which PPARγ contributes to the host immunoprotective effects during bacterial infection and suggest a role for PPARγ immunotherapy for P. aeruginosa infections. PMID:27091928

  6. Solar disinfection of Pseudomonas aeruginosa in harvested rainwater: a step towards potability of rainwater.

    Directory of Open Access Journals (Sweden)

    Muhammad T Amin

    Full Text Available Efficiency of solar based disinfection of Pseudomonas aeruginosa (P. aeruginosa in rooftop harvested rainwater was evaluated aiming the potability of rainwater. The rainwater samples were exposed to direct sunlight for about 8-9 hours and the effects of water temperature (°C, sunlight irradiance (W/m2, different rear surfaces of polyethylene terephthalate bottles, variable microbial concentrations, pH and turbidity were observed on P. aeruginosa inactivation at different weathers. In simple solar disinfection (SODIS, the complete inactivation of P. aeruginosa was obtained only under sunny weather conditions (>50°C and >700 W/m2 with absorptive rear surface. Solar collector disinfection (SOCODIS system, used to improve the efficiency of simple SODIS under mild and weak weather, completely inactivated the P. aeruginosa by enhancing the disinfection efficiency of about 20% only at mild weather. Both SODIS and SOCODIS systems, however, were found inefficient at weak weather. Different initial concentrations of P. aeruginosa and/or Escherichia coli had little effects on the disinfection efficiency except for the SODIS with highest initial concentrations. The inactivation of P. aeruginosa increased by about 10-15% by lowering the initial pH values from 10 to 3. A high initial turbidity, adjusted by adding kaolin, adversely affected the efficiency of both systems and a decrease, about 15-25%; in inactivation of P. aeruginosa was observed. The kinetics of this study was investigated by Geeraerd Model for highlighting the best disinfection system based on reaction rate constant. The unique detailed investigation of P. aeruginosa disinfection with sunlight based disinfection systems under different weather conditions and variable parameters will help researchers to understand and further improve the newly invented SOCODIS system.

  7. Extracellular synthesis of silver and gold nanoparticles by Sporosarcina koreensis DC4 and their biological applications.

    Science.gov (United States)

    Singh, Priyanka; Singh, Hina; Kim, Yeon Ju; Mathiyalagan, Ramya; Wang, Chao; Yang, Deok Chun

    2016-05-01

    The present study highlights the microbial synthesis of silver and gold nanoparticles by Sporosarcina koreensis DC4 strain, in an efficient way. The synthesized nanoparticles were characterized by ultraviolet-visible spectrophotometry, which displayed maximum absorbance at 424nm and 531nm for silver and gold nanoparticles, respectively. The spherical shape of nanoparticles was characterized by field emission transmission electron microscopy. The energy dispersive X-ray spectroscopy and elemental mapping were displayed the purity and maximum elemental distribution of silver and gold elements in the respective nanoproducts. The X-ray diffraction spectroscopy results demonstrate the crystalline nature of synthesized nanoparticles. The particle size analysis demonstrate the nanoparticles distribution with respect to intensity, volume and number of nanoparticles. For biological applications, the silver nanoparticles have been explored in terms of MIC and MBC against pathogenic microorganisms such as Vibrio parahaemolyticus, Escherichia coli, Salmonella enterica, Bacillus anthracis, Bacillus cereus and Staphylococcus aureus. Moreover, the silver nanoparticles in combination with commercial antibiotics, such as vancomycin, rifampicin, oleandomycin, penicillin G, novobiocin, and lincomycin have been explored for the enhancement of antibacterial activity and the obtained results showed that 3μg concentration of silver nanoparticles sufficiently enhance the antimicrobial efficacy of commercial antibiotics against pathogenic microorganism. Furthermore, the silver nanoparticles potential has been reconnoitered for the biofilm inhibition by S. aureus, Pseudomonas aeruginosa and E. coli and the results revealed sufficient activity at 6μg concentration. In addition, gold nanoparticles have been applied for catalytic activity, for the reduction of 4-nitrophenol to 4-aminophenol using sodium borohydride and positive results were attained. PMID:26992796

  8. Quorum-sensing-regulated virulence factors in Pseudomonas aeruginosa are toxic to Lucilia sericata maggots

    OpenAIRE

    Andersen, A S; Joergensen, B.; Bjarnsholt, T.; Johansen, H; Karlsmark, T.; Givskov, M; Krogfelt, K A

    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 PAO1 in a simple assay with emphasis on the quorum-sensing (QS)-regulated virulence. The maggots were challenged with GFP-tagged P. aeruginosa wild-type (WT) PAO1 and a GFP-tagged P. aeruginosa ΔlasR ...

  9. Characterization of a novel extended-spectrum beta-lactamase from Pseudomonas aeruginosa.

    OpenAIRE

    Nordmann, P.; Ronco, E; Naas, T.; Duport, C; Michel-Briand, Y.; Labia, R

    1993-01-01

    A clinical isolate of Pseudomonas aeruginosa RNL-1 showed resistance to extended-spectrum cephalosporins which was inhibited by clavulanic acid. Although this strain contained three plasmids ca. 80, 20, and 4 kb long, the resistance could not be transferred by mating-out assays with P. aeruginosa or Escherichia coli. Cloning of a 2.1-kb Sau3A fragment from P. aeruginosa RNL-1 into plasmid pACYC184 produced pPZ1, a recombinant plasmid that encodes a beta-lactamase. This beta-lactamase (PER-1) ...

  10. Molecular cloning and characterization of the recA gene of Pseudomonas aeruginosa PAO

    International Nuclear Information System (INIS)

    The recA gene of Pseudomonas aeruginosa PAO has been isolated and introduced into Escherichia coli K-12. Resistance to killing by UV irradiation was restored in several RecA-E. coli K-12 hosts by the P. aeruginosa gene, as was resistance to methyl methanesulfonate. Recombination proficiency was also restored, as measured by HfrH-mediated conjugation and by the ability to propagate Fec-phage lambda derivatives. The cloned P. aeruginosa recA gene restored both spontaneous and mitomycin C-stimulated induction of lambda prophage in lysogens of a recA strain of E. coli K-12

  11. Post-translational modifications in Pseudomonas aeruginosa revolutionized by proteomic analysis.

    Science.gov (United States)

    Ouidir, Tassadit; Jouenne, Thierry; Hardouin, Julie

    2016-06-01

    Pseudomonas aeruginosa is an opportunistic pathogen that causes severe infections in vulnerable individuals. It is known that post-translational modifications (PTMs) play a key role in bacterial physiology. Their characterization is still challenging and the recent advances in proteomics allow large-scale and high-throughput analyses of PTMs. Here, we provide an overview of proteomic data about the modified proteins in P. aeruginosa. We emphasize the significant contribution of proteomics in knowledge enhancement of PTMs (phosphorylation, N-acetylation and glycosylation) and we discuss their importance in P. aeruginosa physiology. PMID:26952777

  12. Synthesis and antimicrobial effects of silver nanoparticles

    Directory of Open Access Journals (Sweden)

    S kheybari

    2010-09-01

    Full Text Available "n  "n "nBackground and the purpose of the study:The most prominent nanoparticles for medical uses are nanosilver particles which are famous for their high anti-microbial activity. Silver ion has been known as a metal ion that exhibit anti-mold, anti-microbial and anti-algal properties for a long time. In particular, it is widely used as silver nitrate aqueous solution which has disinfecting and sterilizing actions. The purpose of this study was to evaluate the antimicrobial activity as well as physical properties of the silver nanoparticles prepared by chemical reduction method. "nMethods:Silver nanoparticles (NPs were prepared by reduction of silver nitrate in the presence of a reducing agent and also poly [N-vinylpyrolidone] (PVP as a stabilizer. Two kinds of NPs were synthesized by ethylene glycol (EG and glucose as reducing agent. The nanostructure and particle size of silver NPs were confirmed by scanning electron microscopy (SEM and laser particle analyzer (LPA. The formations of the silver NPs were monitored using ultraviolet-visible spectroscopy. The anti-bacterial activity of silver NPs were assessed by determination of their minimum inhibitory concentrations (MIC against the Gram positive (Staphylococcus aureus and Staphylococcus epidermidis as well as Gram-negative (Escherichia coli and Pseudomonas aeruginosa bacteria. "nResults and Conclusion:The silver nanoparticles were spherical with particle size between 10 to 250 nm. Analysis of the theoretical (Mie light scattering theory and experimental results showed that the silver NPs in colloidal solution had a diameter of approximately 50 nm. "nBoth colloidal silver NPs showed high anti-bacterial activity against Gram positive and Gram negative bacteria. Glucose nanosilver colloids showed a shorter killing time against most of the tested bacteria which could be due to their nanostructures and uniform size distribution patterns.

  13. 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?

    OpenAIRE

    Maria Verônica Guilherme Ferrareze; Vanessa Cristina Leopoldo; Denise de Andrade; Magda Fabbri Issac Silva; Vanderlei José Haas

    2007-01-01

    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 ...

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

    DEFF Research Database (Denmark)

    Johansen, Helle Krogh; Gøtzsche, Peter C

    2015-01-01

    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...... fibrosis. DATA COLLECTION AND ANALYSIS: The authors independently selected trials, assessed them and extracted data. MAIN RESULTS: Six trials were identified. Two trials were excluded since they were not randomised and one old, small trial because it was not possible to assess whether is was randomised....... The three included trials comprised 483, 476 and 37 patients, respectively. No data have been published from one of the large trials, but the company stated in a press release that the trial failed to confirm the results from an earlier study and that further clinical development was suspended. In the...

  15. In vitro inhibition of Pseudomonas aeruginosa adhesion by Xylitol

    Directory of Open Access Journals (Sweden)

    Letícia Pinheiro de Sousa

    2011-10-01

    Full Text Available This study evaluated, in vitro, the antimicrobial activity and the anti-adherent property of xylitol (0.5, 2.5 and 5.0%, w/v on two Pseudomonas aeruginosa strains (ATCC 9027 and clinical. The assay of antimicrobial activity was performed to determine a minimum inhibitory concentration (MIC and the adhesion test was performed, by which the parameters regarding, growth in the culture medium, number of colony forming units (CFUs released and slide evaluation by scanning electron microscopy (SEM were analyzed. The Statistical Package for the Social Sciences (SPSS was employed for statistical analysis. Results showed that xylitol had no antimicrobial activity on these strains; however, the inhibition of bacterial adherence was observed in microphotographs obtained by SEM. These results indicated that xylitol could be a future alternative to combat bacterial colonization.

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

    Directory of Open Access Journals (Sweden)

    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.

  17. Pseudomonas Aeruginosa Resistance Phenotypes and Phenotypic Highlighting Methods

    Science.gov (United States)

    BĂLĂŞOIU, MARIA; BĂLĂŞOIU, A.T.; MĂNESCU, RODICA; AVRAMESCU, CARMEN; IONETE, OANA

    2014-01-01

    Pseudomonas aeruginosa genus bacteria are well known for their increased drug resistance (phenotypic ang genotypic resistance). The most important resistance mechanisms are: enzyme production, reduction of pore expression, reduction of the external membrane proteins expression, efflux systems, topoisomerase mutations. These mechanisms often accumulate and lead to multidrug ressitance strains emergence. The most frequent acquired resistance mechanisms are betalactamase-type enzyme production (ESBLs, AmpC, carbapenemases), which determine variable phenotypes of betalactamines resistance, phenotypes which are associated with aminoglycosides and quinolones resistance. The nonenzymatic drug resistance mechanisms are caused by efflux systems, pore reduction and penicillin-binding proteins (PBP) modification, which are often associated to other resistance mechanisms. Phenotypic methods used for testing these mechanisms are based on highlighting these phenotypes using Kirby Bauer antibiogram, clinical breakpoints, and “cut off” values recommended by EUCAST 2013 standard, version 3.1. PMID:25729587

  18. Antibiofilm effect enhanced by modification of 1,2,3-triazole and palladium nanoparticles on polysulfone membranes

    KAUST Repository

    Cheng, Hong

    2015-08-01

    Biofouling impedes the performance of membrane bioreactors. In this study, we investigated the antifouling effects of polysulfone membranes that were modified by 1,2,3-triazole and palladium nanoparticles. The membranes to be tested were embedded within a drip flow biofilm reactor, and Pseudomonas aeruginosa PAO1 was inoculated and allowed to establish biofilm on the tested membranes. It was found that 1,2,3-triazole and palladium nanoparticles can inhibit the bacterial growth in aerobic and anaerobic conditions. The decrease in bacterial growth was observed along with a decrease in the amount of total polysaccharide and Pel polysaccharide within the biofilm matrix but not the protein content.

  19. Degradation characteristics of two Bacillus strains on the Microcystis aeruginosa

    Institute of Scientific and Technical Information of China (English)

    PEI Hai-yan; HU Wen-rong; QU Yin-bo; MU Rui-min; LI Xiao-cai

    2005-01-01

    The degradation kinetics of strains P05 and P07 and the degradation effects of mixed strain on Microcystis aeruginosa were studied. The results showed that: ( 1 ) The degradation processes of strains P05 and P07 on Microcystis aeruginosa accorded with the first-order reaction model when the range of Chl- a concentration was from 0 to 1500 μg/L. (2) The initial bacterium densities had a strong influence on the degradation velocity. The greater the initial bacterium density was, the faster the degradation was. The degradation velocity constants of P05 were 0.1913, 0.2175 and 0.3092 respectively, when bacterium densities were 4.8×105 , 4.8 × 106, 2.4 × 107 cells/ml. For strain P07, they were 0.1509, 0.1647 and 0.2708. The degradation velocity constant of strain P05 was higher than that of P07 when the bacterium density was under 4.8 × 105 cells/ml, but the constant increasing of P07 was quicker than that of P05. (3) The degradation effects of P05 and P07 strains did not antagonize. When the concentration of Chl-a was high, the degradation effects of mixed strain excelled that of any single strains. But with the decrease of the Chl-a concentration, this advantage was not clear. When the concentration was less than 180 μg/L, the degradation effects of mixed were consistent with that of strain P07.

  20. 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.

  1. Early events of lethal action by tobramycin in Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    The immediate activities of the aminoglycoside antibiotic, tobramycin, were investigated in Pseudomonas aeruginosa PAO1. The influence of carbon growth substate and the antibiotic exposure environment in the magnitude of activity were examined. Lethality by 8 μg/ml tobramycin occurred rapidly (1 to 3 minutes). The release of specific cellular components into the supernatant was associated with lethality. This material was initially detected as an increase in UV-absorbance. Magnesium in the reaction mixture provided protection against lethality and leakage, but did not reverse lethal damage after a 3 minute tobramycin treatment. Also, uptake of 3H-tobramycin was reduced in the presence of magnesium. Cells grown with glucose as a carbon source were more susceptible than organic acid grown cells as was the rapidity and amount of cell damage. Analyses of the leakage material revealed a 2-fold increase of protein in the supernatant after a 1-3 minute treatment which paralleled lethality. A prominent 29 kDa protein was observed by SDS-PAGE in the released material, which has been identified as the periplasmic enzyme, β-lactamase. The immediate activities of tobramycin did not involve (i) release of overall cell protein, (ii) massive loss of total pool amino acids, (iii) cell lysis, (iv) inhibition of proline uptake, (v) release of lipopolysaccharide, or (vi) leakage of ATP. Electron microscopy showed no apparent damage after a 3 minute exposure. 40% inhibition of protein synthesis had occurred by 3 minutes of exposure, while release of UV-absorbing material and lethality were detectable after only 1 minute. Resistant cystic fibrosis isolates of P. aeruginosa did not leak under the same experimental conditions, but one of two susceptible strains examined did show increased UV-absorbance following treatment

  2. 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.

  3. Fructooligosacharides reduce Pseudomonas aeruginosa PAO1 pathogenicity through distinct mechanisms.

    Directory of Open Access Journals (Sweden)

    Mercedes Ortega-González

    Full Text Available Pseudomonas aeruginosa is ubiquitously present in the environment and acts as an opportunistic pathogen on humans, animals and plants. We report here the effects of the prebiotic polysaccharide inulin and its hydrolysed form FOS on this bacterium. FOS was found to inhibit bacterial growth of strain PAO1, while inulin did not affect growth rate or yield in a significant manner. Inulin stimulated biofilm formation, whereas a dramatic reduction of the biofilm formation was observed in the presence of FOS. Similar opposing effects were observed for bacterial motility, where FOS inhibited the swarming and twitching behaviour whereas inulin caused its stimulation. In co-cultures with eukaryotic cells (macrophages FOS and, to a lesser extent, inulin reduced the secretion of the inflammatory cytokines IL-6, IL-10 and TNF-α. Western blot experiments indicated that the effects mediated by FOS in macrophages are associated with a decreased activation of the NF-κB pathway. Since FOS and inulin stimulate pathway activation in the absence of bacteria, the FOS mediated effect is likely to be of indirect nature, such as via a reduction of bacterial virulence. Further, this modulatory effect is observed also with the highly virulent ptxS mutated strain. Co-culture experiments of P. aeruginosa with IEC18 eukaryotic cells showed that FOS reduces the concentration of the major virulence factor, exotoxin A, suggesting that this is a possible mechanism for the reduction of pathogenicity. The potential of these compounds as components of antibacterial and anti-inflammatory cocktails is discussed.

  4. Fructooligosacharides reduce Pseudomonas aeruginosa PAO1 pathogenicity through distinct mechanisms.

    Science.gov (United States)

    Ortega-González, Mercedes; Sánchez de Medina, Fermín; Molina-Santiago, Carlos; López-Posadas, Rocío; Pacheco, Daniel; Krell, Tino; Martínez-Augustin, Olga; Abdelali, Daddaoua

    2014-01-01

    Pseudomonas aeruginosa is ubiquitously present in the environment and acts as an opportunistic pathogen on humans, animals and plants. We report here the effects of the prebiotic polysaccharide inulin and its hydrolysed form FOS on this bacterium. FOS was found to inhibit bacterial growth of strain PAO1, while inulin did not affect growth rate or yield in a significant manner. Inulin stimulated biofilm formation, whereas a dramatic reduction of the biofilm formation was observed in the presence of FOS. Similar opposing effects were observed for bacterial motility, where FOS inhibited the swarming and twitching behaviour whereas inulin caused its stimulation. In co-cultures with eukaryotic cells (macrophages) FOS and, to a lesser extent, inulin reduced the secretion of the inflammatory cytokines IL-6, IL-10 and TNF-α. Western blot experiments indicated that the effects mediated by FOS in macrophages are associated with a decreased activation of the NF-κB pathway. Since FOS and inulin stimulate pathway activation in the absence of bacteria, the FOS mediated effect is likely to be of indirect nature, such as via a reduction of bacterial virulence. Further, this modulatory effect is observed also with the highly virulent ptxS mutated strain. Co-culture experiments of P. aeruginosa with IEC18 eukaryotic cells showed that FOS reduces the concentration of the major virulence factor, exotoxin A, suggesting that this is a possible mechanism for the reduction of pathogenicity. The potential of these compounds as components of antibacterial and anti-inflammatory cocktails is discussed. PMID:24465697

  5. Study on the release routes of allelochemicals from Pistia stratiotes Linn., and its anti-cyanobacteria mechanisms on Microcystis aeruginosa.

    Science.gov (United States)

    Wu, Xiang; Wu, Hao; Ye, Jinyun; Zhong, Bin

    2015-12-01

    Allelochemicals in Pistia stratiotes Linn. have a strong anti-cyanobacteria effect on Microcystis aeruginosa. To further determine the release routes of allelochemicals in P. stratiotes and understand their anti-cyanobacteria mechanisms, we aimed to systematically investigate the allelopathic effects of leaf leachates, leaf volatilization, root exudates, and residue decomposition of P. stratiotes on M. aeruginosa. The influences of P. stratiotes allelochemicals on the physiological properties of M. aeruginosa were also studied. Root exudates of P. stratiotes exhibited the strongest inhibitory effect on M. aeruginosa growth. The residue decomposition and leaf leachates exhibited a relatively strong inhibitory effect on M. aeruginosa growth. By contrast, the leaf volatilization stimulated M. aeruginosa growth. Therefore, root exudation was determined to be the main release route of allelochemicals from P. stratiotes. The mixed culture experiment of P. stratiotes root exudates and M. aeruginosa showed that the allelochemicals released from root exudation had no effect on the electron transfer of M. aeruginosa photosynthetic system II. However, it reduced the phycocyanin (PC) content and phycocyanin to allophycocyanin (PC/APC) ratio in the photosynthetic system. As the root exudates concentration increased, the electrical conductivity (EC) and superoxide anion radical (O2(*-)) values in the M. aeruginosa culture fluid increased significantly, indicating that the allelochemicals released from the root of P. stratiotes inhibited algae growth by affecting the PC and PC/APC levels in photosynthesis, destroying the cell membrane, and increasing O2(*-) content to result in oxidative damage of M. aeruginosa. PMID:26233747

  6. Potent antimicrobial and antibiofilm activities of bacteriogenically synthesized gold-silver nanoparticles against pathogenic bacteria and their physiochemical characterizations.

    Science.gov (United States)

    Ramasamy, Mohankandhasamy; Lee, Jin-Hyung; Lee, Jintae

    2016-09-01

    The objective of this study was to develop a bimetallic nanoparticle with enhanced antibacterial activity that would improve the therapeutic efficacy against bacterial biofilms. Bimetallic gold-silver nanoparticles were bacteriogenically synthesized using γ-proteobacterium, Shewanella oneidensis MR-1. The antibacterial activities of gold-silver nanoparticles were assessed on the planktonic and biofilm phases of individual and mixed multi-cultures of pathogenic Gram negative (Escherichia coli and Pseudomonas aeruginosa) and Gram positive bacteria (Enterococcus faecalis and Staphylococcus aureus), respectively. The minimum inhibitory concentration of gold-silver nanoparticles was 30-50 µM than that of other nanoparticles (>100 µM) for the tested bacteria. Interestingly, gold-silver nanoparticles were more effective in inhibiting bacterial biofilm formation at 10 µM concentration. Both scanning and transmission electron microscopy results further accounted the impact of gold-silver nanoparticles on biocompatibility and bactericidal effect that the small size and bio-organic materials covering on gold-silver nanoparticles improves the internalization and thus caused bacterial inactivation. Thus, bacteriogenically synthesized gold-silver nanoparticles appear to be a promising nanoantibiotic for overcoming the bacterial resistance in the established bacterial biofilms. PMID:27117745

  7. Characterization of Imipenem Unsusceptible Pseudomonas Aeruginosa Isolates from Inpatients without Carbapenem Treatment

    Institute of Scientific and Technical Information of China (English)

    Yi-hai Gu; Xiao Zhu; Jing-yun Li; Jun Zhang; Qing-yuan Zhou; Yue Ma; Chang-qin Hu; Shao-hong Jin; and Sheng-hui Cui

    2013-01-01

    Objective To identify the risk factors for imipenem resistance development and transmission of clinical Pseudomonas aeruginosa isolates. Methods Thirty-seven imipenem unsusceptible Pseudomonas aeruginosa isolates collected from patients in absence of carbapenem treatment were characterized by antimicrobial susceptibility test, pulsed field gel electrophoresis (PFGE) and carbapenem resistant mechanism analysis. Results Before the collection of imipenem unsusceptible Pseudomonas aeruginosa isolates, the average time of patients treated with more than one antimicrobial (20.0 ± 9.5 days, n=16) was signiifcantly longer than those treated with only one antimicrobial (12.6 ± 4.4 days, n=21;t-test, Welch, t=-2.9004, P Conclusions Our data demonstrated that exposure to non-carbapenem drug classes, especially lfuoroquinolones andβ-lactams, may be important risk factors for the spread of carbapenem resistant Pseudomonas aeruginosa.

  8. 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...... garlic-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 cytokine production were used as indicators. The garlic treatment initially provoked a higher degree of inflammation, and significantly improved clearing of the infecting bacteria. The results indicate that a QS-inhibitory extract of garlic renders P. aeruginosa sensitive to tobramycin...

  9. 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

    were analysed that were either eradicated rapidly or persisted despite multiple antimicrobial treatments. Eighty-six early infection episodes were studied. First P. aeruginosa isolates from patients with eradication (36) or persistent infection (16) were included; isolates from patients with...

  10. Investigating the Antibacterial Effects of Plant Extracts on Pseudomonas aeruginosa and Escherichia coli

    Directory of Open Access Journals (Sweden)

    Jahani

    2016-04-01

    Full Text Available Background Scientists are seeking an appropriate alternative method for curing infections caused by resistant bacteria, since drug resistance is continually increasing. Objectives This research aims to discover the function of some medicine plants on pestiferous Pseudomonas aeruginosa and Escherichia coli in humans. Materials and Methods Bacterial strains were obtained from a standard laboratory. The strains of Pseudomonas aeruginosa ATCC27853 and E.coli ATCC25922 bacteria were used for antimicrobial testing of the extractions. Results Our results showed that Teucrium polium extracts have the minimum density of inhibitory for Escherichia coli, 25 ppm, whereas the maximum of this is for Peganum harmala and Prangos ferulaceae with 100 ppm. The lowest minimum concentration inhibitory value of extracts P. harmala, T. polium, T. pratensis and Rumex was found in 25 ppm against P.aeruginosa. Conclusions The results of our study showed that plant extracts have good antibacterial properties against Pseudomonas aeruginosa and Escherichia coli.

  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. Impact of new water systems on healthcare-associated colonization or infection with Pseudomonas aeruginosa

    Science.gov (United States)

    Lefebvre, Annick; Quantin, Catherine; Vanhems, Philippe; Lucet, Jean-Christophe; Bertrand, Xavier; Astruc, Karine; Chavanet, Pascal; Aho-Glélé, Ludwig S.

    2016-01-01

    Aim: We aimed to study the impact of new water systems, which were less contaminated with P. aeruginosa, on the incidence of healthcare-associated P. aeruginosa cases (colonizations or infections) in care units that moved to a different building between 2005 and 2014. Methods: Generalized Estimated Equations were used to compare the incidence of P. aeruginosa healthcare-associated cases according to the building. Results: Twenty-nine units moved during the study period and 2,759 cases occurred in these units. No difference was observed when the new building was compared with older buildings overall. Conclusion: Our results did not support our hypothesis of a positive association between water system contamination and the incidence of healthcare-associated P. aeruginosa cases. These results must be confirmed by linking results of water samples and patients’ data.

  13. Effect of irradiation of electron beam on protein and antioxidized enzyme activity of microcystis aeruginosa

    International Nuclear Information System (INIS)

    Microcystis aeruginosa often threatens human health and safety for its microcystin and bad smell. Its large number and hardness of removal are difficulty for water treatment. In this study, electron beam generated by an accelerator was applied to irradiate Microcystis aeruginosa by dose of l, 2, 3, 4 and 5 kGy. The effect of irradiation on Microcystis aeruginosa characteristic and mechanism was studied by surveying the changing of protein, enzyme activity and photosynthesis rate. The data show that irradiation of 1 kGy has little effect on dissoluble protein, POD and SOD activity. Irradiation of 25 kGy can decrease protein content and destroy the antioxidant system, also the photosynthesis rate decreases obviously, which makes Microcystis aeruginosa lose activity in short time. The result proves that a certain dose of electron beam irradiation can control algae growth and affect its life characteristic efficiently. (authors)

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

    DEFF Research Database (Denmark)

    Marvig, Rasmus Lykke; Dolce, Daniela; Madsen Sommer, Lea Mette; Petersen, Bent; Ciofu, Oana; Campana, Silvia; Molin, Søren; Taccetti, Giovanni; Johansen, Helle Krogh

    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...... strategies. Here, we report the first genomic analysis of P. aeruginosa isolates sampled from Italian CF patients. By genome sequencing of 26 isolates sampled over 19 years from four patients, we elucidated the within-host evolution of clonal lineages in each individual patient. Many of the identified...... understanding of P. aeruginosa within-host genomic evolution, transmission, and population genomics. We conclude that the evolution of the Italian lineages resembles what has been found in other countries....

  15. 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...

  16. 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...

  17. IN-VITRO COMPARATIVE STUDY OF CEFOPERAZONE, CEFTAZIDIME, CEFTIZOXIME, CEFOTAXIME, CEFTRIAXONE AND CEFIXIME AGAINST PSEUDOMONAS AERUGINOSA

    Directory of Open Access Journals (Sweden)

    Humza Ahmad Ullah

    2013-01-01

    Full Text Available The prime intention of this study was the evaluation & accumulation of epidemiological data on the resistance of Pseudomonas aeruginosa, and to compare the activity of different third generation cephalosporins against Pseudomonas aeruginosa. For this purpose Modified Kirby-Bauer Method was used for the determination of sensitivity of antibacterial agents using strains of Pseudomonas aeruginosa ATCC 27853 as control. Total 250 isolates of Pseudomonas aeruginosa were collected from different public and private hospitals of Karachi, Pakistan. In-vitro qualities (i.e. sensitive, resistant and intermediate of six members of third generation cephalosporins (Cefoperazone, Ceftazidime, Ceftizoxime, Cefotaxime, Ceftriaxone and Cefixime were reviewed. Results showed that Cefoperazone was the most effective antibacterial agent (80% sensitive, while the second most effective antibacterial agent was Ceftazidime (70% sensitive. Cefotaxime and Ceftizoxime also showed intermediate activity. Cefixime and Ceftriaxone didn’t show any supportive activity i.e. 0% sensitive at all.

  18. 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

    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...

  19. Detection of N-acylhomoserine lactones in lung tissues of mice infected with Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Wu, H; Song, Z; Hentzer, Morten;

    2000-01-01

    The pathogenesis of Pseudomonas aeruginosa is associated with expression of virulence factors, many of which are controlled by two N:-acylhomoserine lactone (AHL)-based quorum-sensing systems. Escherichia coli strains equipped with a luxR-based monitor system expressing green fluorescent protein...... (GFP) in the presence of exogenous AHL molecules were used to detect the production of AHLs from P. aeruginosa in vivo. Mice were challenged intratracheally with alginate beads containing P. aeruginosa and E. coli and killed on different days after the challenge. By means of confocal scanning laser...... microscopy, GFP-expressing E. coli bacteria could be detected in the lung tissues, indicating production and excretion of AHL molecules in vivo by the infecting P. aeruginosa. AHL signals were detected mainly in lung tissues exhibiting severe pathological changes. These findings support the view that...

  20. INCIDENCE OF FLUOROQUINOLONE RESISTANCE IN PSEUDOMONAS AERUGINOSA FROM URINARY TRACT INFECTIONS

    Directory of Open Access Journals (Sweden)

    Antonia Poiata

    2014-07-01

    Full Text Available The susceptibility of 105 Pseudomonas aeruginosa isolates collected from patients with urinary tract infectionswas assessed by determination of minimum inhibitory concentration (MICs using agar dilution method against thefollowing agents: norfloxacin, ofloxacin, ciprofloxacin and pefloxacin.Resistance rates of P. aeruginosa to tested fluoroquinolones was fairly uniformly distributed between compounds asfollowed: norfloxacin - 52.4%, ofloxacin- 49.5%, ciprofloxacin - 51.4%, pefloxacin - 49.5%. Analysis of cross-resistancein P. aeruginosa showed a correlated magnitude of resistance between fluoroquinolones. Among the P.aeruginosa strainsthe number of those showing simultaneously resistance to all tested agents is high (n=50.The significant increase in fluoroquinolone resistance probably reflects the widspread use of this agent and the clinicaluse of these compunds should be carefully monitored since most bacterial strains shows cross-resitance.

  1. IgG antibodies in early Pseudomonas aeruginosa infection in cystic fibrosis.

    OpenAIRE

    Cordon, S M; Elborn, J. S.; Rayner, R J; Hiller, E. J.; Shale, D. J.

    1992-01-01

    The relationship between IgG antibodies to Pseudomonas aeruginosa and its isolation from sputum was determined in 100 patients with cystic fibrosis observed at intervals of two months for a median period of one year. Only one patient had a raised antibody titre (greater than 22.9 ELISA units) before isolation of P aeruginosa. Initially 65 patients were antibody negative, of whom 48 were also culture negative. Of 24 patients with positive sputum culture and negative antibodies, seven became an...

  2. Phagocytosis of Pseudomonas aeruginosa by polymorphonuclear leukocytes and monocytes: effect of cystic fibrosis serum.

    OpenAIRE

    Thomassen, M J; Demko, C A; Wood, R E; Sherman, J. M.

    1982-01-01

    It has been shown previously that serum from chronically infected patients with cystic fibrosis inhibits the phagocytosis of Pseudomonas aeruginosa by both normal and cystic fibrosis alveolar macrophages. In the present study, the ability of peripheral monocytes and polymorphonuclear leukocytes from normal volunteers and cystic fibrosis patients to phagocytize P. aeruginosa was shown not to be inhibited in the presence of serum from cystic fibrosis patients.

  3. Genome Sequences of Pseudomonas oryzihabitans Phage POR1 and Pseudomonas aeruginosa Phage PAE1

    Science.gov (United States)

    Dyson, Zoe A.; Seviour, Robert J.; Tucci, Joseph

    2016-01-01

    We report the genome sequences of two double-stranded DNA siphoviruses, POR1 infective for Pseudomonas oryzihabitans and PAE1 infective for Pseudomonas aeruginosa. The phage POR1 genome showed no nucleotide sequence homology to any other DNA phage sequence in the GenBank database, while phage PAE1 displayed synteny to P. aeruginosa phages M6, MP1412, and YuA. PMID:27313312

  4. Environmental and molecular characterization of systems which affect genome alteration in pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Pseudomonas aeruginosa is used as a model organism to study genome alteration in freshwater microbial populations and horizontal gene transmission by both transduction and conjugation has been demonstrated. The studies have also provided data which suggest that intracellular genome instability may be increased in the aquatic environment as a result of stresses encountered by the cell in this habitat. The role of the P. aeruginosa recA analog in regulating genome instability is also addressed

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

    Science.gov (United States)

    van Mansfeld, Rosa; de Vrankrijker, Angelica; Brimicombe, Roland; Heijerman, Harry; Teding van Berkhout, Ferdinand; Spitoni, Cristian; 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 the incidence of P. aeruginosa infection in CF patients was investigated through longitudinal protocolized follow-up of respiratory tract infection before and after segregation. In two nested cross-sectional studies in 2007 and 2011 the P. aeruginosa population structure was investigated and clinical parameters were determined in patients with and without infection with the Dutch epidemic P. aeruginosa clone (ST406). Results Of 784 included patients 315 and 382 were at risk for acquiring chronic P. aeruginosa infection before and after segregation. Acquisition rates were, respectively, 0.14 and 0.05 per 1,000 days at risk (HR: 0.66, 95% CI [0.2548–1.541]; p = 0.28). An exploratory subgroup analysis indicated lower acquisition after segregation in children < 15 years of age (HR: 0.43, 95% CI[0.21–0.95]; p = 0.04). P. aeruginosa population structure did not change after segregation and ST406 was not associated with lung function decline, death or lung transplantation. Conclusions Strict segregation was not associated with a statistically significant lower acquisition of chronic P. aeruginosa infection and ST406 was not associated with adverse clinical outcome. After segregation there were no new acquisitions of ST406. In an unplanned exploratory analysis chronic acquisition of P. aeruginosa was lower after implementation of segregation in patients under 15 years of age. PMID:27280467

  6. High Therapeutic Index of Factor C Sushi Peptides: Potent Antimicrobials against Pseudomonas aeruginosa

    OpenAIRE

    Yau, Yin Hoe; Ho, Bow; Tan, Nguan Soon; Ng, Miang Lon; Ding, Jeak Ling

    2001-01-01

    Factor C protein isolated from the horseshoe crab, Carcinoscorpius rotundicauda, has endotoxin binding capability. Synthetic peptides of 34 amino acids based on the sequence of two regions of factor C (Sushi 1 and Sushi 3) as well as their corresponding mutants exhibited activities against 30 clinical isolates of Pseudomonas aeruginosa. Collectively, all four peptides demonstrated exceptionally effective bactericidal activity against P. aeruginosa with 90% minimal bactericidal concentrations ...

  7. The enhancement by surfactants of hexadecane degradation by Pseudomonas aeruginosa varies with substrate availability

    OpenAIRE

    Noordman, WH; Wachter, JHJ; Boer, GJ; Janssen, DB; Boer, Geert J. de

    2002-01-01

    The rhamnolipid biosurfactant produced by Pseudomonas aeruginosa influences various processes related to hydrocarbon degradation. However, degradation can only be enhanced by the surfactant when it stimulates a process that is rate limiting under the applied conditions. Therefore we determined how rhamnolipid influences hexadecane degradation by P. aeruginosa UG2 under conditions differing in hexadecane availability. The rate of hexadecane degradation in shake flask cultures was lower for hex...

  8. Glutathione exhibits antibacterial activity and increases tetracycline efficacy against Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Glutathione(GSH) plays important roles in pulmonary diseases,and inhaled GSH therapy has been used to treat cystic fibrosis(CF) patients in clinical trials.The results in this report revealed that GSH altered the sensitivity of Pseudomonas aeruginosa to different antibiotics through pathways unrelated to the oxidative stress as generally perceived.In addition,GSH and its oxidized form inhibited the growth of P.aeruginosa.

  9. The periplasmic protein TolB as a potential drug target in Pseudomonas aeruginosa.

    OpenAIRE

    Alessandra Lo Sciuto; Regina Fernández-Piñar; Lucia Bertuccini; Francesca Iosi; Fabiana Superti; Francesco Imperi

    2014-01-01

    International audience The Gram-negative bacterium Pseudomonas aeruginosa is one of the most dreaded pathogens in the hospital setting, and represents a prototype of multi-drug resistant "superbug" for which effective therapeutic options are very limited. The identification and characterization of new cellular functions that are essential for P. aeruginosa viability and/or virulence could drive the development of anti-Pseudomonas compounds with novel mechanisms of action. In this study we ...

  10. Control of Candida albicans Metabolism and Biofilm Formation by Pseudomonas aeruginosa Phenazines

    OpenAIRE

    Morales, Diana K.; Grahl, Nora; Okegbe, Chinweike; Dietrich, Lars E. P.; Jacobs, Nicholas J.; Hogan, Deborah A.

    2013-01-01

    ABSTRACT Candida albicans has developmental programs that govern transitions between yeast and filamentous morphologies and between unattached and biofilm lifestyles. Here, we report that filamentation, intercellular adherence, and biofilm development were inhibited during interactions between Candida albicans and Pseudomonas aeruginosa through the action of P. aeruginosa-produced phenazines. While phenazines are toxic to C. albicans at millimolar concentrations, we found that lower concentra...

  11. Pseudomonas aeruginosa Forms Biofilms in Acute Infection Independent of Cell-to-Cell Signaling▿ †

    OpenAIRE

    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.

    2007-01-01

    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 h of infection in thermally injured mice, demonstrating that biofilms contribute to bacterial colonization in acute infections as well. Using light, electron, and confocal scanning laser microscopy, P. aeruginosa biofilms were visualized within burn...

  12. Pseudomonas aeruginosa adapts its iron uptake strategies in function of the type of infections

    OpenAIRE

    Cornelis, Pierre; Dingemans, Jozef

    2013-01-01

    Pseudomonas aeruginosa is a Gram-negative γ-Proteobacterium which is known for its capacity to colonize various niches, including some invertebrate and vertebrate hosts, making it one of the most frequent bacteria causing opportunistic infections. P. aeruginosa is able to cause acute as well as chronic infections and it uses different colonization and virulence factors to do so. Infections range from septicemia, urinary infections, burn wound colonization, and chronic colonization of the lung...

  13. Attenuation of Pseudomonas aeruginosa biofilm formation by Vitexin: A combinatorial study with azithromycin and gentamicin

    OpenAIRE

    Das, Manash C.; Padmani Sandhu; Priya Gupta; Prasenjit Rudrapaul; Utpal C. De; Prosun Tribedi; Yusuf Akhter; Surajit Bhattacharjee

    2016-01-01

    Microbial biofilm are communities of surface-adhered cells enclosed in a matrix of extracellular polymeric substances. Extensive use of antibiotics to treat biofilm associated infections has led to the emergence of multiple drug resistant strains. Pseudomonas aeruginosa is recognised as a model biofilm forming pathogenic bacterium. Vitexin, a polyphenolic group of phytochemical with antimicrobial property, has been studied for its antibiofilm potential against Pseudomonas aeruginosa in combin...

  14. Evolved resistance to colistin and its loss due to genetic reversion in Pseudomonas aeruginosa

    OpenAIRE

    Lee, Ji-Young; Park, Young Kyoung; Chung, Eun Seon; Na, In Young; Ko, Kwan Soo

    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...

  15. In vitro and in vivo screening for novel essential cell-envelope proteins in Pseudomonas aeruginosa

    OpenAIRE

    Regina Fernández-Piñar; Alessandra Lo Sciuto; Alice Rossi; Serena Ranucci; Alessandra Bragonzi; Francesco Imperi

    2015-01-01

    The Gram-negative bacterium Pseudomonas aeruginosa represents a prototype of multi-drug resistant opportunistic pathogens for which novel therapeutic options are urgently required. In order to identify new candidates as potential drug targets, we combined large-scale transposon mutagenesis data analysis and bioinformatics predictions to retrieve a set of putative essential genes which are conserved in P. aeruginosa and predicted to encode cell envelope or secreted proteins. By generating unma...

  16. Effects of azithromycin on Pseudomonas aeruginosa isolates from catheter-associated urinary tract infection

    OpenAIRE

    Xu, Zhi-Gang; Gao, Yu; He, Jian-Guo; Xu, Wei-Feng; Jiang, Mei; JIN, HUAN-SHENG

    2014-01-01

    Pseudomonas aeruginosa is a common pathogenic bacterium in urinary tract infections (UTIs), particularly catheter-associated UTIs. The aim of this study was to investigate the effect of azithromycin (AZM) on P. aeruginosa isolated from UTIs. Isolates were identified by biochemical assays and the Vitek system. Antimicrobial susceptibility was determined using the disk diffusion assay. Biofilm formation and adhesion were assayed using a crystal violet staining method. The swimming motility was ...

  17. Antibiotic Resistance Profiles and Quorum Sensing-Dependent Virulence Factors in Clinical Isolates of Pseudomonas Aeruginosa

    OpenAIRE

    Wang, Huafu; Tu, Faping; Gui, Zhihong; Lu, Xianghong; Chu, Weihua

    2013-01-01

    Pseudomonas aeruginosa produces multiple virulence factors that have been associated with quorum sensing. The aim of this study was to evaluate the prevalence of drug resistant profiles and quorum sensing related virulence factors. Pseudomonas aeruginosa were collected from different patients hospitalized in China, the isolates were tested for their susceptibility to different common antimicrobial drugs and detected QS-related virulence factors. We identified 170 isolates displaying impaired ...

  18. Clustering of Pseudomonas aeruginosa transcriptomes from planktonic cultures, developing and mature biofilms reveals distinct expression profiles

    OpenAIRE

    Saqi Mansoor; Hurst Jacob M; Papakonstantinopoulou Anastasia; Paccanaro Alberto; Waite Richard D; Littler Eddie; Curtis Michael A

    2006-01-01

    Abstract Background Pseudomonas aeruginosa is a genetically complex bacterium which can adopt and switch between a free-living or biofilm lifestyle, a versatility that enables it to thrive in many different environments and contributes to its success as a human pathogen. Results Transcriptomes derived from growth states relevant to the lifestyle of P. aeruginosa were clustered using three different methods (K-means, K-means spectral and hierarchical clustering). The culture conditions used fo...

  19. Local imipenem activity against Pseudomonas aeruginosa decreases in vivo in the presence of siliconized latex.

    Science.gov (United States)

    Pichardo, C; Conejo, M C; Docobo-Pérez, F; Velasco, C; López-Rojas, R; García, I; Pachón-Ibáñez, M E; Rodríguez, J M; Pachón, J; Pascual, A

    2011-02-01

    Zinc eluted from siliconized latex (SL) increases resistance of Pseudomonas aeruginosa to imipenem in vitro. A foreign body peritonitis model was used to evaluate the activity of imipenem using SL or silicone (S) implants. No differences were observed in mortality, positive blood cultures and tissue bacterial counts between SL and S implants. Implant-associated counts, however, were significantly higher in the SL group. It is concluded that SL decreases the activity of imipenem against P. aeruginosa. PMID:20936490

  20. Synergistic effect of fosfomycin and fluoroquinolones against Pseudomonas aeruginosa growing in a biofilm.

    OpenAIRE

    Mikuniya, Takeshi; Kato, Yoshihisa; Kariyama, Reiko; Monden, Koichi; Hikida, Muneo; Kumon, Hiromi

    2005-01-01

    Ulifloxacin is the active form of the prodrug prulifloxacin and shows a highly potent antipseudomonal activity. In this study, we examined the combined effect of fosfomycin and ulifloxacin against Pseudomonas aeruginosa (P. aeruginosa) growing in a biofilm using a modified Robbins device with artificial urine, and compared it to that of the combination of fosfomycin and ciprofloxacin or levofloxacin. An ATP bioluminescence assay was used to evaluate the antibacterial activity of the agents ag...

  1. Role of Interleukin-17 in defense against pseudomonas aeruginosa infection in lungs

    OpenAIRE

    Xu, Xilin; Shao, Bing; Wang, Ran; ZHOU, SIJING; Tang, Zhongzhi; Lu, Weihua; XIONG, SHENGDAO

    2014-01-01

    Background: Pseudomonas aeruginosa may cause severe or even fatal infection in hosts with immunodeficiency. Interleukin-17 (IL-17) is a newly discovered pro-inflammatory cytokine, which promotes the recruitment and activation of neutrophils in the respiratory tract by inducing release of chemokine C-X-C. Objective: This study was conducted to explore the role of IL-17 in host defense against acute pseudomonas aeruginosa infection in lungs. Methods: The expression of IL-17 and its downstream e...

  2. [The protective activity of 2 normal immunoglobulin preparations for intravenous administration in experimental Pseudomonas aeruginosa infection].

    Science.gov (United States)

    Vasilev, Ch L; Veleva, K V; Tekelieva, R Kh; Pencheva, P I

    1991-02-01

    The antibody levels in 18 batches of the preparations of human immunoglobulin, Immunovenin and Immunovenin-Intact, for intravenous injection were determined in the enzyme immunoassay with the use of the mixture of P. aeruginosa lipopolysaccharide antigens of seven immunotypes. The average antibody titers in these preparations were identical. The preparations were found to have protective action against P. aeruginosa experimental infection in mice. PMID:1907793

  3. An examination of potential differences in biofilm production among different genotypes of Pseudomonas aeruginosa

    OpenAIRE

    Vasiljević Zorica; Jovčić B.; Ćirković Ivana; Đukić Slobodanka

    2014-01-01

    In the present study, we have examined if there is any difference in biofilm production among different genotypes of Pseudomonas aeruginosa. The study investigated 526 non-duplicate P. aeruginosa isolated from clinical specimens and from a hospital environment. Isolates were grouped into thirty-five genotypes based on an identical ERIC2-band pattern. Biofilm formation was quantified by the microtiter plate test and all strains were classified into the follo...

  4. Class 1 integron and Imipenem Resistance in Clinical Isolates of Pseudomonas aeruginosa: Prevalence and Antibiotic Susceptibility

    Directory of Open Access Journals (Sweden)

    M Milani

    2010-12-01

    Full Text Available Background and Objectives: Pseudomonas aeruginosa is one of the most important causative agents of nosocomial infections especially in ICU and burn units. P. aeruginosa infections are normally difficult to eradicate due to acquired resistance to many antibiotics. Recent appearance of carbapenem resistant P. aeruginosa isolates is considered a major healthcare problem. The present study was conducted to detect class 1 integron and antibiotic susceptibility profiles of imipenem-sensitive and resistant clinical isolates of P. aeruginosa."nMaterials and Methods: Antibiotic susceptibility profiles and minimum inhibitory concentration against imipenem was studied in 160 clinical isolates of P. aeruginosa by disk agar diffusion method and Etest, respectively. Detection of class 1 integron was performed by the PCR method. Demographic and microbiological data were compared between imipenem susceptible and non-susceptible isolates by the SPSS software."nResults: PCR results showed that 90 (56.3% of P. aeruginosa isolates carried class 1 integron. Antibiotic susceptibility results revealed that 93 (58.1% were susceptible and 67 (41.9% were non-susceptible to imipenem. Comparison of antibiotic susceptibility patterns showed high level of drug resistance among imipenem non-susceptible isolates. We found that MDR phenotype, presence of class 1 integron and hospitalization in ICU and burn units were significantly associated with imipenem non-susceptible isolates."nConclusion: The high frequency of imipenem resistance was seen among our P. aeruginosa isolates. Since carbapenems are considered as the last drugs used for treatment of P. aeruginosa infections, it is crucial to screen imipenem non-susceptible isolates in infection control and optimal therapy.

  5. Dissemination of Carbapenemase-Producing Enterobacteriaceae and Pseudomonas aeruginosa in Romania

    OpenAIRE

    Dortet, Laurent; Flonta, Mirela; Boudehen, Yves-Marie; Creton, Elodie; Bernabeu, Sandrine; Vogel, Anaïs; Naas, Thierry

    2015-01-01

    Fifteen carbapenemase-producing Enterobacteriaceae isolates and 12 carbapenemase-producing Pseudomonas aeruginosa isolates were recovered from patients hospitalized between August 2011 and March 2013 at the Hospital of Infectious Disease, Cluj-Napoca, Romania. One KPC-, nine NDM-1-, four OXA-48-, and one VIM-4-producing Enterobacteriaceae isolates along with 11 VIM-2-producing and one IMP-13-producing P. aeruginosa isolates were recovered from clinical samples. All carbapenemase genes were lo...

  6. 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...

  7. Phylogenetic Distribution of CRISPR-Cas Systems in Antibiotic-Resistant Pseudomonas aeruginosa

    OpenAIRE

    van Belkum, Alex; Soriaga, Leah B.; LaFave, Matthew C.; Akella, Srividya; Veyrieras, Jean-Baptiste; Barbu, E. Magda; Shortridge, Dee; Blanc, Bernadette; Hannum, Gregory; Zambardi, Gilles; Miller, Kristofer; Enright, Mark C; Mugnier, Nathalie; Brami, Daniel; Schicklin, Stéphane

    2015-01-01

    ABSTRACT Pseudomonas aeruginosa is an antibiotic-refractory pathogen with a large genome and extensive genotypic diversity. Historically, P. aeruginosa has been a major model system for understanding the molecular mechanisms underlying type I clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated protein (CRISPR-Cas)-based bacterial immune system function. However, little information on the phylogenetic distribution and potential role of these CRISPR-Cas syste...

  8. Mechanism of Enhanced Activity of Liposome-Entrapped Aminoglycosides against Resistant Strains of Pseudomonas aeruginosa

    OpenAIRE

    Mugabe, Clement; Halwani, Majed; Azghani, Ali O.; Lafrenie, Robert M.; Omri, Abdelwahab

    2006-01-01

    Pseudomonas aeruginosa is inherently resistant to most conventional antibiotics. The mechanism of resistance of this bacterium is mainly associated with the low permeability of its outer membrane to these agents. We sought to assess the bactericidal efficacy of liposome-entrapped aminoglycosides against resistant clinical strains of P. aeruginosa and to define the mechanism of liposome-bacterium interactions. Aminoglycosides were incorporated into liposomes, and the bactericidal efficacies of...

  9. A quorum-sensing inhibitor blocks Pseudomonas aeruginosa virulence and biofilm formation

    OpenAIRE

    O’Loughlin, Colleen T.; Miller, Laura C.; Siryaporn, Albert; Drescher, Knut; Semmelhack, Martin F.; Bassler, Bonnie L.

    2013-01-01

    In this study, we prepare synthetic molecules and analyze them for inhibition of the Pseudomonas quorum-sensing receptors LasR and RhlR. Our most effective compound, meta-bromo-thiolactone, not only prevents virulence factor expression and biofilm formation but also protects Caenorhabditis elegans and human A549 lung epithelial cells from quorum-sensing–mediated killing by Pseudomonas aeruginosa. This anti–quorum-sensing molecule is capable of influencing P. aeruginosa virulence in tissue cul...

  10. Prospective study of serum antibodies to Pseudomonas aeruginosa exoproteins in cystic fibrosis.

    OpenAIRE

    Hollsing, A E; Granström, M; Vasil, M L; Wretlind, B; Strandvik, B

    1987-01-01

    Serum immunoglobulin G to four purified antigens from Pseudomonas aeruginosa, phospholipase C, alkaline protease, exotoxin A, and elastase, were determined in 62 patients with cystic fibrosis by enzyme-linked immunosorbent assay. The patients were followed for 12 to 24 months in a prospective study. Increased titers, i.e., titers more than 2 standard deviations above those of normal controls, were exclusively found in patients chronically colonized with P. aeruginosa and not in patients harbo...

  11. Pseudomonas aeruginosa alkaline protease degrades human gamma interferon and inhibits its bioactivity.

    OpenAIRE

    Horvat, R T; Parmely, M J

    1988-01-01

    This study was performed to determine the effect of Pseudomonas aeruginosa on gamma interferon (IFN-gamma) production by antigen-stimulated human T-cell clones. Crude bacterial filtrates prepared from certain strains of P. aeruginosa inhibited IFN-gamma production by T cells and reduced the antiviral activity of preformed IFN-gamma. Bacterial filtrates prepared from mutant strains that did not produce the exoenzyme alkaline protease (AP) did not inhibit IFN-gamma activity. The inhibitory acti...

  12. Role of Pseudomonas aeruginosa exoenzymes in lung infections of patients with cystic fibrosis.

    OpenAIRE

    Döring, G; Goldstein, W; A. Röll; Schiøtz, P O; Høiby, N; Botzenhart, K.

    1985-01-01

    We investigated the role of Pseudomonas aeruginosa exoenzymes in cystic fibrosis lung infection in the presence and absence of specific serum antibodies. In sputa of 21 cystic fibrosis patients, concentrations of P. aeruginosa proteases and exotoxin A were determined by sensitive radioimmunoassays. In all sputa, detection of exoenzymes was negative (less than or equal to 10 ng). Positive serum antibody titers to bacterial exoenzymes were found in the majority of patients. Purified immunoglobu...

  13. Specific cleavage of human type III and IV collagens by Pseudomonas aeruginosa elastase.

    OpenAIRE

    Heck, L W; Morihara, K; McRae, W B; Miller, E J

    1986-01-01

    Purified Pseudomonas aeruginosa elastase cleaved human type III and IV collagens with the formation of specific cleavage products. Furthermore, type I collagen appeared to be slowly cleaved by both P. aeruginosa elastase and alkaline protease. These cleavage fragments from type III and IV collagens were separated from the intact collagen chains by SDS polyacrylamide gradient gel electrophoresis run under reducing conditions, and they were detected by their characteristic Coomassie blue staini...

  14. Selective Sweeps and Parallel Pathoadaptation Drive Pseudomonas aeruginosa Evolution in the Cystic Fibrosis Lung

    OpenAIRE

    Diaz Caballero, Julio; Clark, Shawn T.; Coburn, Bryan; Zhang, Yu; Wang, Pauline W.; Donaldson, Sylva L.; Tullis, D Elizabeth; Yau, Yvonne C. W.; Waters, Valerie J; Hwang, David M.; Guttman, David S.

    2015-01-01

    ABSTRACT Pulmonary infections caused by Pseudomonas aeruginosa are a recalcitrant problem in cystic fibrosis (CF) patients. While the clinical implications and long-term evolutionary patterns of these infections are well studied, we know little about the short-term population dynamics that enable this pathogen to persist despite aggressive antimicrobial therapy. Here, we describe a short-term population genomic analysis of 233 P. aeruginosa isolates collected from 12 sputum specimens obtained...

  15. Production of Pseudomonas aeruginosa Intercellular Small Signaling Molecules in Human Burn Wounds

    OpenAIRE

    Yok-Ai Que; Ronen Hazan; Ryan, Colleen M.; Sylvain Milot; François Lépine; Martha Lydon; Rahme, Laurence G

    2011-01-01

    Pseudomonas aeruginosa has developed a complex cell-to-cell communication system that relies on low-molecular weight excreted molecules to control the production of its virulence factors. We previously characterized the transcriptional regulator MvfR, that controls a major network of acute virulence functions in P. aeruginosa through the control of its ligands, the 4-hydroxy-2-alkylquinolines (HAQs)—4-hydroxy-2-heptylquinoline (HHQ) and 3,4-dihydroxy-2-heptylquinoline (PQS). Though HHQ and PQ...

  16. Effects of proteases on the structure and activity of Pseudomonas aeruginosa exotoxin A.

    OpenAIRE

    Morihara, K; Sanai, Y; Tsuzuki, H; Jyoyama, H; Hirose, K; Homma, J Y; Kato, I

    1981-01-01

    The effects of various proteases on the enzymatic or biological activity and structure of exotoxin A from Pseudomonas aeruginosa were systematically studied. The toxin was extremely resistant to treatment with various enzymes. The lethality of the toxin disappeared upon treatment with P. aeruginosa protease and elastase, thermolysin, and trypsin with a long incubation time (5h) in the presence of a high enzyme concentration (molar concentration of enzyme to toxin, 1:10 or 1:20), but was littl...

  17. Growth of genetically engineered Pseudomonas aeruginosa and Pseudomonas putida in soil and rhizosphere.

    OpenAIRE

    Yeung, K H; Schell, M A; Hartel, P. G.

    1989-01-01

    The effect of the addition of a recombinant plasmid containing the pglA gene encoding an alpha-1,4-endopolygalacturonase from Pseudomonas solanacearum on the growth of Pseudomonas aeruginosa and Pseudomonas putida in soil and rhizosphere was determined. Despite a high level of polygalacturonase production by genetically engineered P. putida and P. aeruginosa, the results suggest that polygalacturonase production had little effect on the growth of these strains in soil or rhizosphere.

  18. Pseudomonas aeruginosa bacteremia secondary to acute right leg cellulitis: case of community-acquired infection

    OpenAIRE

    Wahab, Asrul Abdul; Rahman, M.M.

    2013-01-01

    Pseudomonas aeruginosa is a gram-negative bacillus that causes wide spectrum clinical infections. However, it is most frequently associated with hospital-acquired infection. In this case a 58-year-old male with underlying hypertension and dyslipidaemia was admitted for acute right leg cellulitis. Pseudomonas aeruginosa was identified from the case, though it was not a usual suspected organism. It might be due to community-acquired infection.

  19. Extracellular Ser/Thr/Tyr phosphorylated proteins of Pseudomonas aeruginosa PA14 strain.

    Science.gov (United States)

    Ouidir, Tassadit; Jarnier, Frédérique; Cosette, Pascal; Jouenne, Thierry; Hardouin, Julie

    2014-09-01

    Protein phosphorylation on serine, threonine, and tyrosine is known to be involved in a wide variety of cellular processes, signal transduction, and bacterial virulence. We characterized, for the first time, the extracellular phosphoproteins of the Pseudomonas aeruginosa PA14 strain. We identified 28 phosphoproteins (59 phosphosites) including enzymes, with various phosphorylation sites, known as potent secreted virulence factors in P. aeruginosa. The high phosphorylation level of these virulence factors might reflect a relationship between Ser/Thr/Tyr phosphorylation and virulence. PMID:24965220

  20. Use of In-Biofilm Expression Technology To Identify Genes Involved in Pseudomonas aeruginosa Biofilm Development†

    OpenAIRE

    Finelli, Antonio; Gallant, Claude V.; Jarvi, Keith; Burrows, Lori L.

    2003-01-01

    Mature Pseudomonas aeruginosa biofilms form complex three-dimensional architecture and are tolerant of antibiotics and other antimicrobial compounds. In this work, an in vivo expression technology system, originally designed to study virulence-associated genes in complex mammalian environments, was used to identify genes up-regulated in P. aeruginosa grown to a mature (5-day) biofilm. Five unique cloned promoters unable to promote in vitro growth in the absence of purines after recovery from ...

  1. Swimming Behavior of Pseudomonas aeruginosa Studied by Holographic 3D Tracking

    OpenAIRE

    Vater, Svenja M.; Weiße, Sebastian; Maleschlijski, Stojan; Lotz, Carmen; Koschitzki, Florian; Schwartz, Thomas; Obst, Ursula; Rosenhahn, Axel

    2014-01-01

    Holographic 3D tracking was applied to record and analyze the swimming behavior of Pseudomonas aeruginosa. The obtained trajectories allow to qualitatively and quantitatively analyze the free swimming behavior of the bacterium. This can be classified into five distinct swimming patterns. In addition to the previously reported smooth and oscillatory swimming motions, three additional patterns are distinguished. We show that Pseudomonas aeruginosa performs helical movements which were so far on...

  2. Antimicrobial activity of the crude ethanol extract and fractions from Eugenia uniflora leaves against Pseudomonas aeruginosa

    OpenAIRE

    Tatiana S. Fiuza; Sabóia Morais, Simone M.T.; José R. Paula; Leonice M.F. Tresvenzol; Carmo Filho, José R.; Fabiana C Pimenta

    2009-01-01

    This study evaluated the antimicrobial activity of the crude ethanol extract and fractions from Eugenia uniflora L. leaves against Pseudomonas aeruginosa. A total of 72 P. aeruginosa isolated from patients of three hospitals in Goiânia and 8 standard strains were selected to test antimicrobial activity. The bacteria susceptibility profile against 15 antimicrobial agents was determined using the disc diffusion method. The minimum inhibitory concentration of the crude ethanol extract and the et...

  3. Treatment of Pseudomonas aeruginosa-infected orthopedic prostheses with ceftazidime-ciprofloxacin antibiotic combination.

    OpenAIRE

    Brouqui, P; Rousseau, M C; Stein, A.; Drancourt, M; D. Raoult

    1995-01-01

    Indwelling device infections are associated with considerable morbidity and extremely high cost. Pseudomonas aeruginosa is the most frequent gram-negative etiologic agent associated with infections of indwelling catheters and foreign body implants. It is generally agreed that eradication of infection in the presence of a foreign body requires removal of the foreign body. Using a combination of ceftazidime and ciprofloxacin, we cured nine of nine patients with P. aeruginosa-infected osteosynth...

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

    DEFF Research Database (Denmark)

    Ciofu, O; Beveridge, T J; Kadurugamuwa, J; Walther-Rasmussen, J; Høiby, N

    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...... 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....

  5. Comparison of Antiseptics’ Efficacy on Pseudomonas Aeruginosa, StaphylococcusEpidermidis and Enterobacter Aeruginosa in Hospital of Imam Khomeini (Urmia

    Directory of Open Access Journals (Sweden)

    Fahim Amini

    2012-04-01

    Full Text Available Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background and Objectives: Nosocomial infection is the cause of deaths, morbidity, higher costs and increased length of stay in hospitals. Correct and appropriate use of antiseptic and disinfectants play an important role in reducing infections. In this study the efficacy of antiseptics on bacteria causing hospital infections has been studied.Materials and Methods: This study was conducted in the laboratory of Imam Khomeini Hospital of Uremia. In this study the Antimicrobial activity of Descocid, Korsolex basic, Mikrobac forte and persidin 1% was studied against bacteria causing hospital infections such as Enterobacter aeruginosa 1221 (NCTC 10006, Staphylococcus epidermidis (PTCC: 1435 (Cip81.55 and Pseudomonas aeruginosa Strain PAO1. Sensitivities of bacteria were determined by Minimum inhibitory Concentration (MIC and Minimum bactericidal Concentration (MBC antiseptics. In the second stage, the concentration of antiseptics was prepared according to the manufacturer's suggested protocol and the effect of antimicrobial agents were studied at the certain concentration and contact time.Result: All disinfectants (Descocid, Korsolex basic, Mikrobac forte concentration and contact time, Accordance with the manufacturer's brochure, had inhibitory effect on all bacteria. That this is consistent with the manufacturer's brochure. Persidin one percent in concentration of from 2 and 4 V/V % and exposure time 5 minutes could not inhibit the growth of bacterial. But at concentrations of 10 and 20% respectively 15 and 30 minutes exposure time, all three types of bacteria can be inhibited, which is consistent with the manufacturer's claims.Conclusion: In this study, the efficacy of antiseptics was determined with the Micro-dilution method recommended by the NCCLS. Korsolex basic, weakest antiseptics (the highest MIC for the inhibition of three bacteria was determined

  6. Lysozyme-coated silver nanoparticles for differentiating bacterial strains on the basis of antibacterial activity

    Science.gov (United States)

    Ashraf, Sumaira; Chatha, Mariyam Asghar; Ejaz, Wardah; Janjua, Hussnain Ahmed; Hussain, Irshad

    2014-10-01

    Lysozyme, an antibacterial enzyme, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles adopting various strategies. The synthesized particles were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering (DLS), and TEM to observe their morphology and surface chemistry. The silver nanoparticles were evaluated for their antimicrobial activity against several bacterial species and various bacterial strains within the same species. The cationic silver nanoparticles were found to be more effective against Pseudomonas aeruginosa 3 compared to other bacterial species/strains investigated. Some of the bacterial strains of the same species showed variable antibacterial activity. The difference in antimicrobial activity of these particles has led to the conclusion that antimicrobial products formed from silver nanoparticles may not be equally effective against all the bacteria. This difference in the antibacterial activity of silver nanoparticles for different bacterial strains from the same species may be due to the genome islands that are acquired through horizontal gene transfer (HGT). These genome islands are expected to possess some genes that may encode enzymes to resist the antimicrobial activity of silver nanoparticles. These silver nanoparticles may thus also be used to differentiate some bacterial strains within the same species due to variable silver resistance of these variants, which may not possible by simple biochemical tests.

  7. An environmentally benign antimicrobial nanoparticle based on a silver-infused lignin core

    Science.gov (United States)

    Richter, Alexander P.; Brown, Joseph S.; Bharti, Bhuvnesh; Wang, Amy; Gangwal, Sumit; Houck, Keith; Cohen Hubal, Elaine A.; Paunov, Vesselin N.; Stoyanov, Simeon D.; Velev, Orlin D.

    2015-09-01

    Silver nanoparticles have antibacterial properties, but their use has been a cause for concern because they persist in the environment. Here, we show that lignin nanoparticles infused with silver ions and coated with a cationic polyelectrolyte layer form a biodegradable and green alternative to silver nanoparticles. The polyelectrolyte layer promotes the adhesion of the particles to bacterial cell membranes and, together with silver ions, can kill a broad spectrum of bacteria, including Escherichia coli, Pseudomonas aeruginosa and quaternary-amine-resistant Ralstonia sp. Ion depletion studies have shown that the bioactivity of these nanoparticles is time-limited because of the desorption of silver ions. High-throughput bioactivity screening did not reveal increased toxicity of the particles when compared to an equivalent mass of metallic silver nanoparticles or silver nitrate solution. Our results demonstrate that the application of green chemistry principles may allow the synthesis of nanoparticles with biodegradable cores that have higher antimicrobial activity and smaller environmental impact than metallic silver nanoparticles.

  8. Antibacterial Activity of Green Synthesized Silver Nanoparticles Using Vasaka (Justicia adhatoda L.) Leaf Extract.

    Science.gov (United States)

    Bose, Debadin; Chatterjee, Someswar

    2015-06-01

    There is an increasing demand for silver nanoparticles due to its wide applicability in various area of biological science such as in field of antimicrobial and therapeutics, biosensing, drug delivery etc. To use in bioprocess the silver nanoparticles should be biocompatible and free from toxic chemicals. In the present study we report a cost effective and environment friendly route for green synthesis of silver nanoparticles using Vasaka (Justicia adhatoda L.) leaf extract as reducing as well as capping agent. This plant has been opted for the present study for its known medicinal properties and it is easily available. The biosynthesized silver nanoparticles are characterized by UV-Vis spectroscopy and TEM analysis. It is observed the nanoparticles are well shaped and the average particle size is 20 nm in the range of 5-50 nm. The antibacterial activity of these nanoparticles against Pseudomonas aeruginosa MTCC 741 has been measured by disc diffusion method, agar cup assay and serial dilution turbidity measurement assay. The results show green synthesized silver nanoparticles, using Vasaka leaf extract, have a potential to inhibit the growth of bacteria. PMID:25805902

  9. Lessons Learned from Surveillance of Antimicrobial Susceptibilities of Pseudomonas aeruginosa at a Large Academic Medical Center

    Directory of Open Access Journals (Sweden)

    Brett H. Heintz

    2010-04-01

    Full Text Available This research report assessed the differences in resistance rates and antimicrobial usage-versus-susceptibility relationships of Pseudomonas aeruginosa found in various hospital patient care areas. A simplified case control study was also performed to identify patient-specific risk factors associated with cefepime-resistant P. aeruginosa isolates. Last, we determined the consequence of combining mucoid and non-mucoid derived antimicrobial susceptibilities of P. aeruginosa into hospital antibiograms. Overall, susceptibility rates remained lower in the intensive care units (ICUs compared to the non-ICU patient care areas, except for cefepime over the last time period. Cefepime utilization and antimicrobial-resistance rates among P. aeruginosa isolates had a significant relationship. Decreased meropenem exposure was associated with lower resistance rates relative to cefepime. Risk factors independently associated with cefepime-resistant P. aeruginosa were structural lung disease, ICU admission, recent third generation cephalosporin use, frequent hospital admission and non-urine isolates. Large and statistically significant differences were observed between non-mucoid and combined percent susceptibility data for aminoglycosides. To control antimicrobial resistance and optimize initial empiric antimicrobial therapy, antimicrobial susceptibility and utilization patterns in specific patient care areas should be monitored and risk factors for antimicrobial resistance should be assessed. Mucoid strains of P. aeruginosa should not be included into antimicrobial susceptibility data as this may underestimate activity of most antipseudomonal agents.

  10. 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.

  11. Evolved resistance to colistin and its loss due to genetic reversion in Pseudomonas aeruginosa.

    Science.gov (United States)

    Lee, Ji-Young; Park, Young Kyoung; Chung, Eun Seon; Na, In Young; Ko, Kwan Soo

    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 and five colistin resistance determinants in the P5 and P155 lineages, respectively. Lipid A in colistin-resistant mutants was modified through the addition of 4-amino-L-arabinose; this modification was absent in colistin-susceptible revertant strains. Many amino acid substitutions that emerged during the acquisition of colistin resistance were reversed in colistin-susceptible revertants. We demonstrated that evolved colistin resistance in P. aeruginosa was mediated by a complicated regulatory network that likely emerges through diverse genetic alterations. Colistin-resistant P. aeruginosa became susceptible to the colistin upon its withdrawal because of genetic reversion. The mechanisms through which P. aeruginosa acquires and loses colistin resistance have implications on the treatment options that can be applied against P. aeruginosa infections, with respect to improving bactericidal efficacy and preventing further resistance to antibiotics. PMID:27150578

  12. Evolution and adaptation in Pseudomonas aeruginosa biofilms driven by mismatch repair system-deficient mutators.

    Directory of Open Access Journals (Sweden)

    Adela M Luján

    Full Text Available Pseudomonas aeruginosa is an important opportunistic pathogen causing chronic airway infections, especially in cystic fibrosis (CF patients. The majority of the CF patients acquire P. aeruginosa during early childhood, and most of them develop chronic infections resulting in severe lung disease, which are rarely eradicated despite intensive antibiotic therapy. Current knowledge indicates that three major adaptive strategies, biofilm development, phenotypic diversification, and mutator phenotypes [driven by a defective mismatch repair system (MRS], play important roles in P. aeruginosa chronic infections, but the relationship between these strategies is still poorly understood. We have used the flow-cell biofilm model system to investigate the impact of the mutS associated mutator phenotype on development, dynamics, diversification and adaptation of P. aeruginosa biofilms. Through competition experiments we demonstrate for the first time that P. aeruginosa MRS-deficient mutators had enhanced adaptability over wild-type strains when grown in structured biofilms but not as planktonic cells. This advantage was associated with enhanced micro-colony development and increased rates of phenotypic diversification, evidenced by biofilm architecture features and by a wider range and proportion of morphotypic colony variants, respectively. Additionally, morphotypic variants generated in mutator biofilms showed increased competitiveness, providing further evidence for mutator-driven adaptive evolution in the biofilm mode of growth. This work helps to understand the basis for the specific high proportion and role of mutators in chronic infections, where P. aeruginosa develops in biofilm communities.

  13. Pseudomonas cepacia adherence to respiratory epithelial cells is enhanced by Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Pseudomonas aeruginosa and Pseudomonas cepacia are both opportunistic pathogens of patients with cystic fibrosis. The binding characteristics of these two species were compared to determine if they use similar mechanisms to adhere to respiratory epithelial cells. P. cepacia 249 was shown to be piliated, but there was no detectable homology between P. aeruginosa pilin gene probes and P. cepacia genomic DNA. P. cepacia and P. aeruginosa did not appear to compete for epithelial receptors. In the presence of purified P. aeruginosa pili, the adherence of 35S-labeled strain 249 to respiratory epithelial monolayers was unaffected, while that of P. aeruginosa PAO1 was decreased by 55%. The binding of P. cepacia 249 and 715j was increased by 2.4-fold and 1.5-fold, respectively, in the presence of an equal inoculum of PAO1. Interbacterial agglutination contributed to the increased adherence of P. cepacia, as the binding of 249 was increased twofold in the presence of irradiated PAO1. PAO1 exoproducts had a marked effect in enhancing the ability of the P. cepacia strains to adhere to the epithelial monolayers. A PAO1 supernatant increased the binding of 249 by eightfold and that of 715j by fourfold. Thus, there appears to be a synergistic relationship between P. aeruginosa and P. cepacia in which PAO1 exoproducts modify the epithelial cell surface, exposing receptors and facilitating increased P. cepacia attachment

  14. ANTIBACTERIAL ACTIVITY OF TRADITIONAL HERBS AND STANDARD ANTIBIOTICS AGAINST POULTRY ASSOCIATED PSEUDOMONAS AERUGINOSA

    Directory of Open Access Journals (Sweden)

    Affia Rafique

    2012-10-01

    Full Text Available Present study aims to access the antibacterial activity of medicinal plants and antibiotics against poultry associated Pseudomonas aeruginosa. P. aeruginosa is the most widespread avian pathogen and it produces a range of toxins and enzymes that may contribute to pathogenicity. P. aeruginosa was isolated from the chicken liver and identified through biochemical methods. The antibacterial activity of extracts of medicinal herbs and various antibiotics were analyzed against P. aeruginosa through agar disc diffusion method. P. aeruginosa was susceptible against Norfloxacin, Chloramphenicol, Streptomycin, Gentamicin, Tobramycin, and Ciprofloxacin. Whereas, moderately susceptible in case of Oxytetracycline, Neomycin, Lincomycin, and Sulfomethoxyzol. It was also analyzed that Ampicillin, Tetracycline, Penicillin G and Trimethoprim had no effect. Among the plants tested C. zylanicum, C. cyminum, T. ammi, S. aromaticum and green part of M. charantia were most active. The maximum antibacterial activity was calculated by the extracts of isoamylalcohol of C. zylanicum, C. cyminum, T. ammi, S. aromaticum, and ethanolic and methanol extract of green part of M. charantia against P. aeruginosa. This study indicated that these medicinal plants could be the potential source for antimicrobial agents. Hence, these medicinal plants can be further subjected to isolation of the therapeutic antimicrobials and further pharmacological evaluation.

  15. Interactions between Microcystis aeruginosa and coexisting amoxicillin contaminant at different phosphorus levels.

    Science.gov (United States)

    Liu, Ying; Chen, Shi; Chen, Xiao; Zhang, Jian; Gao, Baoyu

    2015-10-30

    Microcystis aeruginosa was cultured with 0.05-5 mg L(-1) of phosphorus and exposed to 200-500 ng L(-1) of amoxicillin for seven days. Amoxicillin presented no significant effect (p>0.05) on the growth of M. aeruginosa at phosphorus levels of 0.05 and 0.2 mg L(-1), but stimulated algal growth as a hormesis effect at phosphorus levels of 1 and 5 mg L(-1). Phosphorus and amoxicillin affected the contents of chlorophyll-a, adenosine triphosphate (ATP) and malondialdehyde, the expression of psbA and rbcL, as well as the activities of adenosinetriphosphatase and glutathione S-transferase in similar manners, but regulated the production and release of microcystins and the activities of superoxide dismutase and peroxidase in different ways. Increased photosynthesis activity was related with the ATP consumption for the stress response to amoxicillin, and the stress response was enhanced as the phosphorus concentration increased. The biodegradation of amoxicillin by M. aeruginosa increased from 11.5% to 28.2% as the phosphorus concentration increased. Coexisting amoxicillin aggravated M. aeruginosa pollution by increasing cell density and concentration of microcystins, while M. aeruginosa alleviated amoxicillin pollution via biodegradation. The interactions between M. aeruginosa and amoxicillin were significantly regulated by phosphorus (p<0.05) and led to a complicated situation of combined pollution. PMID:25956638

  16. Ibuprofen modifies the inflammatory response of the murine lung to Pseudomonas aeruginosa.

    Science.gov (United States)

    Sordelli, D O; Cerquetti, M C; el-Tawil, G; Ramwell, P W; Hooke, A M; Bellanti, J A

    1985-08-01

    In chronic P. aeruginosa infection, lung tissue damage is induced by either the microorganism or the inflammatory response. We investigated, in an animal model, whether a non-steroidal anti-inflammatory drug, ibuprofen, reduced lung inflammation produced by P. aeruginosa. Lung lavages, pulmonary clearance of P. aeruginosa and lung pathology were studied in CD-1 mice injected with sodium ibuprofenate. A single dose of the drug, injected immediately after 30 min exposure to the P. aeruginosa aerosol, decreased the recruitment of granulocytes into airways in a dose-dependent manner. Pretreatment with 2 doses of the drug 18 and 6 h before the P. aeruginosa challenge was even more effective. The kinetics of changes in prostaglandin E2, 6-keto-prostaglandin F1 alpha and thromboxane B2 concentrations in lung lavage fluids after P. aeruginosa aerosol were also modified by ibuprofen. Moreover, ibuprofen treatment did not impair lung clearance of the challenge microorganisms, and the animals had less inflammation of the lungs. PMID:3863757

  17. Virus-Induced Type I Interferon Deteriorates Control of Systemic Pseudomonas Aeruginosa Infection

    Directory of Open Access Journals (Sweden)

    Katja Merches

    2015-07-01

    Full Text Available Background: Type I interferon (IFN-I predisposes to bacterial superinfections, an important problem during viral infection or treatment with interferon-alpha (IFN-α. IFN-I-induced neutropenia is one reason for the impaired bacterial control; however there is evidence that more frequent bacterial infections during IFN-α-treatment occur independently of neutropenia. Methods: We analyzed in a mouse model, whether Pseudomonas aeruginosa control is influenced by co-infection with the lymphocytic choriomeningitis virus (LCMV. Bacterial titers, numbers of neutrophils and the gene-expression of liver-lysozyme-2 were determined during a 24 hours systemic infection with P. aeruginosa in wild-type and Ifnar-/- mice under the influence of LCMV or poly(I:C. Results: Virus-induced IFN-I impaired the control of Pseudomonas aeruginosa. This was associated with neutropenia and loss of lysozyme-2-expression in the liver, which had captured P. aeruginosa. A lower release of IFN-I by poly(I:C-injection also impaired the bacterial control in the liver and reduced the expression of liver-lysozyme-2. Low concentration of IFN-I after infection with a virulent strain of P. aeruginosa alone impaired the bacterial control and reduced lysozyme-2-expression in the liver as well. Conclusion: We found that during systemic infection with P. aeruginosa Kupffer cells quickly controlled the bacteria in cooperation with neutrophils. Upon LCMV-infection this cooperation was disturbed.

  18. Respiratory syncytial virus infection enhances Pseudomonas aeruginosa biofilm growth through dysregulation of nutritional immunity.

    Science.gov (United States)

    Hendricks, Matthew R; Lashua, Lauren P; Fischer, Douglas K; Flitter, Becca A; Eichinger, Katherine M; Durbin, Joan E; Sarkar, Saumendra N; Coyne, Carolyn B; Empey, Kerry M; Bomberger, Jennifer M

    2016-02-01

    Clinical observations link respiratory virus infection and Pseudomonas aeruginosa colonization in chronic lung disease, including cystic fibrosis (CF) and chronic obstructive pulmonary disease. The development of P. aeruginosa into highly antibiotic-resistant biofilm communities promotes airway colonization and accounts for disease progression in patients. Although clinical studies show a strong correlation between CF patients' acquisition of chronic P. aeruginosa infections and respiratory virus infection, little is known about the mechanism by which chronic P. aeruginosa infections are initiated in the host. Using a coculture model to study the formation of bacterial biofilm formation associated with the airway epithelium, we show that respiratory viral infections and the induction of antiviral interferons promote robust secondary P. aeruginosa biofilm formation. We report that the induction of antiviral IFN signaling in response to respiratory syncytial virus (RSV) infection induces bacterial biofilm formation through a mechanism of dysregulated iron homeostasis of the airway epithelium. Moreover, increased apical release of the host iron-binding protein transferrin during RSV infection promotes P. aeruginosa biofilm development in vitro and in vivo. Thus, nutritional immunity pathways that are disrupted during respiratory viral infection create an environment that favors secondary bacterial infection and may provide previously unidentified targets to combat bacterial biofilm formation. PMID:26729873

  19. Growth inhibition and oxidative damage of Microcystis aeruginosa induced by crude extract of Sagittaria trifolia tubers.

    Science.gov (United States)

    Li, Jiang; Liu, Yunguo; Zhang, Pingyang; Zeng, Guangming; Cai, Xiaoxi; Liu, Shaobo; Yin, Yicheng; Hu, Xinjiang; Hu, Xi; Tan, Xiaofei

    2016-05-01

    Aquatic macrophytes are considered to be promising in controlling harmful cyanobacterial blooms. In this research, an aqueous extract of Sagittaria trifolia tubers was prepared to study its inhibitory effect on Microcystis aeruginosa in the laboratory. Several physiological indices of M. aeruginosa, in response to the environmental stress, were analyzed. Results showed that S. trifolia tuber aqueous extract significantly inhibited the growth of M. aeruginosa in a concentration-dependent way. The highest inhibition rate reached 90% after 6 day treatment. The Chlorophyll-a concentration of M. aeruginosa cells decreased from 343.1 to 314.2μg/L in the treatment group. The activities of superoxide dismutase and peroxidase and the content of reduced glutathione in M. aeruginosa cells initially increased as a response to the oxidative stress posed by S. trifolia tuber aqueous extract, but then decreased as time prolonged. The lipid peroxidation damage of the cyanobacterial cell membranes was reflected by the malondialdehyde level, which was notably higher in the treatment group compared with the controls. It was concluded that the oxidative damage of M. aeruginosa induced by S. trifolia tuber aqueous extract might be one of the mechanisms for the inhibitory effects. PMID:27155407

  20. Green Synthesis and Characterization of Silver Nanoparticles for Antimicrobial Activity Against Burn Wounds Contaminating Bacteria

    Science.gov (United States)

    Rout, Anandini; Jena, Padan K.; Sahoo, Debasish; Parida, Umesh K.; Bindhani, Birendra K.

    2014-04-01

    Silver nanoparticles (AgNPs) were prepared from the plant extract of N. arbor-tristis under atmospheric conditions through green synthesis and characterized by various physicochemical techniques like UV-Visible spectroscopy, IR Spectra, energy dispersive X-ray spectrometry (EDS), X-ray diffraction and transmission electron microscopy (TEM) and the results confirmed the synthesis of homogeneous and stable AgNPs by the plant extracts. The antimicrobial activity of AgNPs was investigated against most common bacteria found in burn wound Staphylococcus epidermidis and Pseudomonas aeruginosa. In these tests, Mueller Hinton agar plates were used with AgNPs of various concentrations, supplemented in liquid systems. P. aeruginosa was inhibited at the low concentration of AgNPs, whereas the growth-inhibitory effect on S. epidermidis was mild. These results suggest that AgNPs can be used as effective growth inhibitors of various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems.

  1. Antibacterial cotton fibers treated with silver nanoparticles and quaternary ammonium salts.

    Science.gov (United States)

    Kang, Chan Kyu; Kim, Sam Soo; Kim, Soojung; Lee, Jintae; Lee, Jin-Hyung; Roh, Changhyun; Lee, Jaewoong

    2016-10-20

    Cotton fibers were treated chemically with glycidyltrimethylammonium chloride (GTAC), a quaternary ammonium salt, and coated with silver nanoparticles/3-mercaptopropyltrimethoxysilane (3-MPTMS) to increase the antibacterial efficacy. The coating process was accomplished by soaking the cotton fibers into a GTAC solution followed by a dry-cure method, and silver colloid/3-MPTMS solution was then applied at 43°C for 90min. The properties of the cotton fibers were analyzed by scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis. SEM showed a rough surface when the cotton fibers were treated with GTAC/3-MPTMS/silver nanoparticles due to the increasing surface attachment. The existence of silver and 3-MPTMS on the cotton fibers was confirmed by XPS. The cotton fibers treated with both GTAC and silver nanoparticles showed synergistic antibacterial properties against P. aeruginosa. PMID:27474649

  2. Enhanced retention of bacteria by TiO2 nanoparticles in saturated porous media

    Science.gov (United States)

    Gentile, Guillermina J.; Fidalgo de Cortalezzi, María M.

    2016-08-01

    The simultaneous transport of TiO2 nanoparticles and bacteria Pseudomonas aeruginosa in saturated porous media was investigated. Nanoparticle and bacterium size and surface charge were measured as a function of electrolyte concentration. Sand column breakthrough curves were obtained for single and combined suspensions, at four different ionic strengths. DLVO and classical filtration theories were employed to model the interactions between particles and between particles and sand grains. Attachment of TiO2 to the sand was explained by electrostatic forces and these nanoparticles acted as bonds between the bacteria and the sand, leading to retention. Presence of TiO2 significantly increased the retention of bacteria in the sand bed, but microorganisms were released when nanomaterial influx ceased. The inclusion of nanomaterials in saturated porous media may have implications for the design and operation of sand filters in water treatment.

  3. Development of nitrocellulose membrane filters impregnated with different biosynthesized silver nanoparticles applied to water purification.

    Science.gov (United States)

    Fernández, Jorge G; Almeida, César A; Fernández-Baldo, Martín A; Felici, Emiliano; Raba, Julio; Sanz, María I

    2016-01-01

    Bactericidal water filters were developed. For this purpose, nitrocellulose membrane filters were impregnated with different biosynthesized silver nanoparticles. Silver nanoparticles (AgNPs) from Aspergillus niger (AgNPs-Asp), Cryptococcus laurentii (AgNPs-Cry) and Rhodotorula glutinis (AgNPs-Rho) were used for impregnating nitrocellulose filters. The bactericidal properties of these nanoparticles against Escherichia coli, Enterococcus faecalis and Pseudomona aeruginosa were successfully demonstrated. The higher antimicrobial effect was observed for AgNPs-Rho. This fact would be related not only to the smallest particles, but also to polysaccharides groups that surrounding these particles. Moreover, in this study, complete inhibition of bacterial growth was observed on nitrocellulose membrane filters impregnated with 1 mg L(-1) of biosynthesized AgNPs. This concentration was able to reduce the bacteria colony count by over 5 orders of magnitude, doing suitable for a water purification device. PMID:26695258

  4. Staphylococcus aureus Alters Growth Activity, Autolysis, and Antibiotic Tolerance in a Human Host-Adapted Pseudomonas aeruginosa Lineage

    DEFF Research Database (Denmark)

    Frydenlund Michelsen, Charlotte; Christensen, Anne-Mette; Bojer, Martin Saxtorph;

    2014-01-01

    Interactions among members of polymicrobial infections or between pathogens and the commensal flora may determine disease outcomes. Pseudomonas aeruginosa and Staphylococcus aureus are important opportunistic human pathogens and are both part of the polymicrobial infection communities in human...... hosts. In this study, we analyzed the in vitro interaction between S. aureus and a collection of P. aeruginosa isolates representing different evolutionary steps of a dominant lineage, DK2, that have evolved through decades of growth in chronically infected patients. While the early adapted P....... aeruginosa DK2 strains outcompeted S. aureus during coculture on agar plates, we found that later P. aeruginosa DK2 strains showed a commensal-like interaction, where S. aureus was not inhibited by P. aeruginosa and the growth activity of P. aeruginosa was enhanced in the presence of S. aureus. This effect...

  5. Photobiologic-mediated fabrication of silver nanoparticles with antibacterial activity.

    Science.gov (United States)

    Lee, Jeong-Ho; Lim, Jeong-Muk; Velmurugan, Palanivel; Park, Yool-Jin; Park, Youn-Jong; Bang, Keuk-Soo; Oh, Byung-Taek

    2016-09-01

    We present the simple, eco-friendly synthesis of silver nanoparticles (AgNPs) using sunlight or green, red, blue, or white LED light together with Dryopteris crassirhizoma rhizome extract (DCRE) as the reducing and capping agent. The preliminary indication of AgNP production was a color change from yellowish green to brown after light exposure in the presence of DCRE. Optimization of parameters such as pH, inoculum dose, and metal ion concentration played an important role in achieving nanoparticle production in 30min. The spectroscopic and morphological properties of AgNPs were characterized using UV-Vis spectroscopy through the presence of a characteristic surface plasmon resonance (SPR) band for AgNPs, Fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), and X-ray diffraction (XRD). The FT-IR results indicated that the phytochemical present in DCRE was the probable reducing/capping agent involved in the synthesis of AgNPs, and light radiation enhanced nanoparticle production. HR-TEM revealed that the AgNPs were almost spherical with an average size of 5-60nm under all light sources. XRD studies confirmed the face cubic center (fcc) unit cell structure of AgNPs. The synthesized AgNPs showed good antimicrobial activity against Bacillus cereus and Pseudomonas aeruginosa. This study will bring a new insight in ecofriendly production of metal nanoparticles. PMID:27348063

  6. Eco-friendly synthesis of silver and gold nanoparticles with enhanced bactericidal activity and study of silver catalyzed reduction of 4-nitrophenol

    Science.gov (United States)

    Naraginti, Saraschandra; Sivakumar, A.

    2014-07-01

    The present study reports a simple and robust method for synthesis of silver and gold nanoparticles using Coleus forskohlii root extract as reducing and stabilizing agent. Stable silver nanoparticles (AgNPs) and gold nanopoarticles (AuNPs) were formed on treatment of an aqueous silver nitrate (AgNO3) and chloroauric acid (HAuCl4) solutions with the root extract. The nanoparticles obtained were characterized by UV-Visible spectroscopy, Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). UV-Vis and TEM analysis indicate that with higher quantities of root extract, the interaction is enhanced leading to size reduction of spherical metal nanoparticles. XRD confirms face-centered cubic phase and the diffraction peaks can be attributed to (1 1 1), (2 0 0), (2 2 2) and (3 1 1) planes for these nanoparticles. These synthesized Ag and Au nanoparticles were found to exhibit excellent bactericidal activity against clinically isolated selected pathogens such as Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). The synthesized AgNPs were also found to function as an efficient green catalyst in the reduction of anthropogenic pollutant 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride, which was apparent from the periodical color change from bright yellow to colorless, after the addition of AgNPs.

  7. A comparison of two informative SNP-based strategies for typing Pseudomonas aeruginosa isolates from patients with cystic fibrosis

    OpenAIRE

    Syrmis, Melanie W.; Kidd, Timothy J.; Moser, Ralf J.; Kay A Ramsay; Gibson, Kristen M; Anuj, Snehal; Bell, Scott C.; Wainwright, Claire E.; Grimwood, Keith; Nissen, Michael,; Sloots, Theo P.; Whiley, David M.

    2014-01-01

    Background Molecular typing is integral for identifying Pseudomonas aeruginosa strains that may be shared between patients with cystic fibrosis (CF). We conducted a side-by-side comparison of two P. aeruginosa genotyping methods utilising informative-single nucleotide polymorphism (SNP) methods; one targeting 10 P. aeruginosa SNPs and using real-time polymerase chain reaction technology (HRM10SNP) and the other targeting 20 SNPs and based on the Sequenom MassARRAY platform (iPLEX20SNP). Metho...

  8. Alginate is not a significant component of the extracellular polysaccharide matrix of PA14 and PAO1 Pseudomonas aeruginosa biofilms

    OpenAIRE

    Wozniak, Daniel J.; Wyckoff, Timna J. O.; Starkey, Melissa; Keyser, Rebecca; Azadi, Parastoo; O'Toole, George A.; Parsek, Matthew R.

    2003-01-01

    The bacterium Pseudomonas aeruginosa causes chronic respiratory infections in cystic fibrosis (CF) patients. Such infections are extremely difficult to control because the bacteria exhibit a biofilm-mode of growth, rendering P. aeruginosa resistant to antibiotics and phagocytic cells. During the course of infection, P. aeruginosa usually undergoes a phenotypic switch to a mucoid colony, which is characterized by the overproduction of the exopolysaccharide alginate. Alginate overproducti...

  9. Manuka honey treatment of biofilms of Pseudomonas aeruginosa results in the emergence of isolates with increased honey resistance

    OpenAIRE

    Camplin, Aimee L; Maddocks, Sarah E.

    2014-01-01

    Background Medical grade manuka honeys are well known to be efficacious against Pseudomonas aeruginosa being bactericidal and inhibiting the development of biofilms; moreover manuka honey effectively kills P. aeruginosa embedded within an established biofilm. Sustained honey resistance has not been previously documented for planktonic or biofilm P. aeruginosa. Methods Minimum inhibitory concentrations for manuka honey and antibiotics were determined using broth micro-dilution methods. Minimum...

  10. Retrospective analysis of antibiotic susceptibility patterns of respiratory isolates of Pseudomonas aeruginosa in a Turkish University Hospital

    OpenAIRE

    Akkurt Ibrahim; Ozdemir Levent; Bakici Mustafa; Gonlugur Ugur; Icagasioglu Serhat; Gultekin Fusun

    2003-01-01

    Abstract Background Lower respiratory tract infections due to Pseudomonas aeruginosa have a high mortality rate. Antibacterial activity of various antibiotics against P. aeruginosa isolated from each hospital depends on the variety or amount of antibiotics used in each hospital. Method A total of 249 respiratory isolates of Pseudomonas aeruginosa in Sivas (Turkey) were included between January-1999 and January-2002. Isolates were tested against 14 different antibiotics by a disc diffusion met...

  11. Trappin-2 Promotes Early Clearance of Pseudomonas aeruginosa through CD14-Dependent Macrophage Activation and Neutrophil Recruitment

    OpenAIRE

    Wilkinson, TS; Dhaliwal, K; Hamilton, TW; Lipka, AF; Farrell, L.; Davidson, DJ; Duffin, R.; Morris, AC; Haslett, C; Govan, JRW; Gregory, CD; Sallenave, J-M; Simpson, AJ

    2009-01-01

    Microaspiration of Pseudomonas aeruginosa contributes to the pathogenesis of nosocomial pneumonia. Trappin-2 is a host defense peptide that assists with the clearance of P. aeruginosa through undefined mechanisms. A model of macrophage interactions with replicating P. aeruginosa (strain PA01) in serum-free conditions was developed, and the influence of subantimicrobial concentrations of trappin-2 was subsequently studied. PA01 that was pre-incubated with trappin-2 (...

  12. Pseudomonas aeruginosa outbreak in a pediatric oncology care unit caused by an errant water jet into contaminated siphons.

    Science.gov (United States)

    Schneider, Henriette; Geginat, Gernot; Hogardt, Michael; Kramer, Alexandra; Dürken, Matthias; Schroten, Horst; Tenenbaum, Tobias

    2012-06-01

    We analyzed an outbreak of invasive infections with an exotoxin U positive Pseudomonas aeruginosa strain within a pediatric oncology care unit. Environmental sampling and molecular characterization of the Pseudomonas aeruginosa strains led to identification of the outbreak source. An errant water jet into the sink within patient rooms was observed. Optimized outbreak management resulted in an abundance of further Pseudomonas aeruginosa infections within the pediatric oncology care unit. PMID:22333699

  13. Characterization of Pseudomonas aeruginosa in Burn Patients Using PCR- Restriction Fragment Length Polymorphism and Random Amplified Polymorphic DNA Analysis

    OpenAIRE

    Abdolaziz Rastegar Lari; Bagher Yakhchali; Parviz Owlia; Hassan Salimi

    2010-01-01

    One of the major opportunistic pathogens in patients with burninjuries is Pseudomonas aeruginosa, which causes severe infectionsin burned patients. The objective of the study was to examinethe molecular epidemiology of P. aeruginosa colonization inthe burn unit of Shahid Motahari Hospital in Tehran, Iran. Restrictionfragment length polymorphism (RFLP) and random amplifiedpolymorphic DNA (RAPD) analysis were employed tostudy 127 clinical and two environmental P. aeruginosa isolatescollected fr...

  14. Swarming of Pseudomonas aeruginosa Is Controlled by a Broad Spectrum of Transcriptional Regulators, Including MetR ▿ †

    OpenAIRE

    Yeung, Amy T. Y.; Torfs, Ellen C. W.; Jamshidi, Farzad; Bains, Manjeet; Wiegand, Irith; Hancock, Robert E. W.; Overhage, Joerg

    2009-01-01

    Pseudomonas aeruginosa exhibits swarming motility on semisolid surfaces (0.5 to 0.7% agar). Swarming is a more than just a form of locomotion and represents a complex adaptation resulting in changes in virulence gene expression and antibiotic resistance. In this study, we used a comprehensive P. aeruginosa PA14 transposon mutant library to investigate how the complex swarming adaptation process is regulated. A total of 233 P. aeruginosa PA14 transposon mutants were verified to have alteration...

  15. Negative Pressure Wound Therapy Decreases Mortality in a Murine Model of Burn-Wound Sepsis Involving Pseudomonas aeruginosa Infection

    OpenAIRE

    Yang Liu; Qin Zhou; Yunchuan Wang; Zhengcai Liu; Maolong Dong; Yaojun Wang; Xiao Li; Dahai Hu

    2014-01-01

    BACKGROUND: The colonization of burn wounds by Pseudomonas aeruginosa can lead to septic shock, organ injuries, and high mortality rates. We hypothesized that negative pressure wound therapy (NPWT) would decrease invasion and proliferation of P. aeruginosa within the burn wound and reduce mortality. METHODS: Thermal injuries were induced in anesthetized mice, and P. aeruginosa was applied to the wound surface for 24 h. After removing the burn eschar and debridement, the animals were subjected...

  16. 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...

  17. Cross-Sectional Analysis of Clinical and Environmental Isolates of Pseudomonas aeruginosa: Biofilm Formation, Virulence, and Genome Diversity

    OpenAIRE

    Head, Nathan E.; Yu, Hongwei

    2004-01-01

    Chronic lung infections with Pseudomonas aeruginosa biofilms are associated with refractory and fatal pneumonia in cystic fibrosis (CF). In this study, a group of genomically diverse P. aeruginosa isolates were compared with the reference strain PAO1 to assess the roles of motility, twitching, growth rate, and overproduction of a capsular polysaccharide (alginate) in biofilm formation. In an in vitro biofilm assay system, P. aeruginosa displayed strain-specific biofilm formation that was not ...

  18. Phenotypic and genetic diversities are not correlated in strains of the cyanobacterium Microcystis aeruginosa isolated in SW Spain

    OpenAIRE

    López Rodas, Victoria; Costas, Eduardo; Flores Moya, Antonio

    2013-01-01

    Phenotypic and genetic diversities are not correlated in strains of the cyanobacterium Microcystis aeruginosa isolated in SW Spain. The cyanobacterium Microcystis aeruginosa (Kützing) Kützing is notorious for forming extensive and toxic blooms but the genetic structure of natural populations, and in particular during blooms, remains to be explored. In order to add more knowledge about the genetic structure of M. aeruginosa, we compared phenotypic and genetic variabilities in seventeen strains...

  19. Development and antimicrobial susceptibility studies of in vitro monomicrobial and polymicrobial biofilm models with Aspergillus fumigatus and Pseudomonas aeruginosa

    OpenAIRE

    Manavathu, Elias K.; Vager, Dora L; Vazquez, Jose A

    2014-01-01

    Background Mixed microbial infections of the respiratory tracts with P. aeruginosa and A. fumigatus capable of producing biofilms are commonly found in cystic fibrosis patients. The primary objective of this study was to develop an in vitro model for P. aeruginosa and A. fumigatus polymicrobial biofilm to study the efficacy of various antimicrobial drugs alone and in combinations against biofilm-embedded cells. Simultaneous static cocultures of P. aeruginosa and sporelings were used for the d...

  20. Inhibition of Pseudomonas aeruginosa biofilm formation by 2,2’-bipyridyl, lipoic, kojic and picolinic acids

    Directory of Open Access Journals (Sweden)

    Kübra Çevik

    2015-08-01

    Full Text Available Objective(s:The inhibitory effects of iron chelators, and FeCl3 chelation on biofilm formation and swarming motility were investigated against an opportunistic human pathogen Pseudomonas aeruginosa. Materials and Methods:The inhibitory activity of 2,2’-bipyridyl, lipoic acid, kojic acid and picolinic acidonbiofilm formation of P. aeruginosa strain PAO1 and three clinical isolates (P. aeruginosa  PAK01,P. aeruginosa PAK02 and P. aeruginosa PAK03 were investigated, based on crystal violet assay, and swarming motility test. Results:The kojic, lipoic and picolinic acid inhibited biofilm formation by 5-33% in all tested P. aeruginosa isolates. When chelated iron was added, biofilm inhibition rates were determined to be 39-57%. Among the tested chelators against P. aeruginosa, lipoic acid (84% and kojic acid (68% presented the highest inhibition of swarming motility. This is the first study to report the inhibitory effect of lipoic acid on biofilm formation and swarming motility of P. aeruginosa. Conclusion: It is considered that lipoic and picolinic acids can serve as alternatives for the treatment of the P. aeruginosa infections by inhibiting biofilm formation.

  1. Actividad antimicrobiana del OLEOZON® sobre Staphylococcus aureus y Pseudomonas aeruginosa

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    V. Curtiellas

    2005-01-01

    Full Text Available La actividad antimicrobiana de los aceites vegetales ozonizados suele atribuirse a la acción de los compuestos peroxídicos presentes en los mismos sobre las biomoléculas más sensibles al ataque oxidante, como son los lípidos insaturados y las proteínas que presentan grupos sulfidrilos (SH. Con el objetivo de caracterizar la actividad in vitro del aceite de girasol ozonizado, OLEOZON®, se realizó un estudio empleando las cepas S. aureus ATCC 25923 y P. aeruginosa ATCC 27853. Se determinaron las concentraciones inhibitorias mínimas y las concentraciones bactericidas mínimas de acuerdo a lo establecido por el comité nacional para normas de laboratorio clínico (EE.UU, 2000. Se aplicó Tween 80 y ultrasonido para lograr una emulsión estable entre el aceite y el medio de cultivo. Se realizó un estudio cinético de inactivación empleando una concentración del agente antimicrobiano de 89 mg/mL y tiempos de contacto de 1, 3, 10 y 30 minutos. En paralelo a estos estudios se determinaron las variaciones en la concentración de los grupos sulfidrilos totales mediante lectura a 412 nm del compuesto cromógeno resultante de la reacción con DTNB, (5,5'- ditiobis (2- ácido nitro benzoico. Los valores de las concentraciones inhibitorias mínimas y bactericidas mínimas resultaron menores en S. aureus que en P. Aeruginosa, Mientras que las curvas de inactivación siguieron en ambos casos una cinética de primer orden respecto al número de viables. La determinación de la concentración de los grupos SH totales muestra una disminución significativa para ambos microorganismos desde el primer minuto de contacto con el OLEOZON®, la que es más acentuada en el caso de S. aureus, lo que demuestra que la oxidación de los grupos SH constituye uno de los daños primarios asociados al efecto letal de este medicamento.

  2. Tracking down antibiotic-resistant Pseudomonas aeruginosa isolates in a wastewater network.

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    Céline Slekovec

    Full Text Available The Pseudomonas aeruginosa-containing wastewater released by hospitals is treated by wastewater treatment plants (WWTPs, generating sludge, which is used as a fertilizer, and effluent, which is discharged into rivers. We evaluated the risk of dissemination of antibiotic-resistant P. aeruginosa (AR-PA from the hospital to the environment via the wastewater network. Over a 10-week period, we sampled weekly 11 points (hospital and urban wastewater, untreated and treated water, sludge of the wastewater network and the river upstream and downstream of the WWTP of a city in eastern France. We quantified the P. aeruginosa load by colony counting. We determined the susceptibility to 16 antibiotics of 225 isolates, which we sorted into three categories (wild-type, antibiotic-resistant and multidrug-resistant. Extended-spectrum β-lactamases (ESBLs and metallo-β-lactamases (MBLs were identified by gene sequencing. All non-wild-type isolates (n = 56 and a similar number of wild-type isolates (n = 54 were genotyped by pulsed-field gel electrophoresis and multilocus sequence typing. Almost all the samples (105/110, 95.5% contained P. aeruginosa, with high loads in hospital wastewater and sludge (≥3×10(6 CFU/l or/kg. Most of the multidrug-resistant isolates belonged to ST235, CC111 and ST395. They were found in hospital wastewater and some produced ESBLs such as PER-1 and MBLs such as IMP-29. The WWTP greatly reduced P. aeruginosa counts in effluent, but the P. aeruginosa load in the river was nonetheless higher downstream than upstream from the WWTP. We conclude that the antibiotic-resistant P. aeruginosa released by hospitals is found in the water downstream from the WWTP and in sludge, constituting a potential risk of environmental contamination.

  3. Antimicrobial susceptibilities and bacteriological characteristics of bovine Pseudomonas aeruginosa and Serratia marcescens isolates from mastitis.

    Science.gov (United States)

    Ohnishi, Mamoru; Sawada, Takuo; Hirose, Kazuhiko; Sato, Reiichiro; Hayashimoto, Mizuki; Hata, Eiji; Yonezawa, Chizuko; Kato, Hajime

    2011-12-29

    The presence of metallo-β-lactamase (MBL)-producing and multidrug-resistant Pseudomonas aeruginosa (MDRP) strains among bovine isolates of Gram-negative bacilli, and O-serotypes of bovine Serratia marcescens and P. aeruginosa isolates have been reported rarely. The aims of this study were to (1) elucidate antimicrobial susceptibilities and O-serotypes of P. aeruginosa and S. marcescens isolates from bovine mastitis and the presence of MBL-producers and MDRP strains among them and (2) evaluate their relationships to human isolates. We investigated the MICs of 24 antimicrobials and O-serotypes for 116 P. aeruginosa and 55 S. marcescens isolates in Japan, primarily in 2006. A total of 171 isolates exhibited high antimicrobial susceptibilities with the exception of a partial drug. P. aeruginosa isolates exhibited high susceptibilities of ≥ 95.7% to ciprofloxacin, imipenem, meropenem, piperacillin, ceftazidime, cefepime, cefoperazone/sulbactam, amikacin, tobramycin, and gentamicin; however, they exhibited a susceptibility of only 69.8% to aztreonam. They exhibited substantial resistances to ceftriaxone, enrofloxacin, cefotaxime, and moxalactam. S. marcescens isolates exhibited high susceptibilities of ≥ 90.9% to kanamycin, ceftiofur, sulfamethoxazole-trimethoprim, and the 15 aforementioned drugs, but exhibited resistance to minocycline. Neither MBL-producers nor MDRP strains were detected among the 171 strains. The dominant serotypes of P. aeruginosa isolates were OG, OA, OB, OI, OF, OE, and OK; those of S. marcescens isolates were O6 and O5. Every S. marcescens isolate was pigmented. These findings suggest that bovine P. aeruginosa and S. marcescens isolates differ from human isolates from both antibiogram and phenotypic perspectives, and could help to evaluate differences in bacteriological characteristics between bovine and human isolates. PMID:21783330

  4. Molecular identification and detection of virulence genes among Pseudomonas aeruginosa isolated from different infectious origins

    Directory of Open Access Journals (Sweden)

    Vajiheh Sadat Nikbin

    2012-09-01

    Full Text Available Background and Objectives: Pseudomonas aeruginosa possesses a variety of virulence factors that may contribute to its pathogenicity. The aim of this study was to rapid identification of clinical P. aeruginosa based on PCR amplification oprI and oprL. In order to find out any relation between special virulence factors and special manifestation of P. aeruginosa infections we detected virulence factors among these isolates by PCR. Ribotyping was used to evaluate the clonal relationship between strains with the same genetic patterns of the genes studied.Material and Methods: In this study, 268 isolates of P. aeruginosa were recovered from burn, wound and pulmonary tract infections. PCR of oprI, oprL, toxA, lasB, exoS and nan1 genes was performed. One hundred and four isolates were selected randomly to investigate clonal diversity of the isolates using ribotyping using SmaI.Results and Conclusions: All P. aeruginosa isolates in this study carried oprI, oprL and lasB genes. Difference between exoS prevalence in isolates from pulmonary tract and burn or wound isolates was statistically significant (P<0.05. Prevalence of nan1 and toxA gene was significantly higher in burn and pulmonary tract isolates, respectively. Ribotyping showed that Most of the isolates (87% belonged to clone A and B.PCR of oprI, oprL and toxA genes is recommended for molecular identification of P. aeruginosa. Determination of different virulence genes of P. aeruginosa isolates suggests that they are associated with different levels of intrinsic virulence and pathogenicity. Ribotyping showed that strains with similar virulence genes don’t necessarily have similar ribotype patterns.

  5. Survival, recovery and microcystin release of Microcystis aeruginosa in cold or dark condition

    Science.gov (United States)

    Ding, Yi; Gan, Nanqin; Liu, Jin; Zheng, Lingling; Li, Lin; Song, Lirong

    2016-05-01

    Microcystis often dominates phytoplankton in eutrophic lakes and must survive a long period of cold or dark conditions. However, the survival strategies of Microcystis to withstand cold or dark stress are less well known. In this study, we conducted experiments on the responses of two toxic Microcystis aeruginosa strains (FACHB-905 and FACHB-915) and their microcystin release in conditions of low temperature (15°C or 4°C, with illumination) or darkness, and subsequent recovery in standard conditions (25°C with illumination). On exposure to 15°C, a small decrease in cell viability was observed, but the cell number increased gradually, suggesting that M. aeruginosa FACHB-905 and FACHB-915 cells seem in general tolerant in 15°C. Interestingly, our results show that a higher carotenoid content and microcystin release potentially enhance the fi tness of surviving cells at 15°C. M. aeruginosa cells exposed to lower temperature light stress (4°C) did not completely lose viability and retained the ability to reinitiate growth. In darkness, the maximum quantum yield (F v/F m) and the maximum electron transport rate (ETRmax) values and cell viability of M. aeruginosa cells gradually decreased with time. During the recovery period, the photosynthetic effi ciency of M. aeruginosa reverted to the normal level. Additionally, M. aeruginosa FACHB-905 and FACHB-915 exposed to low temperature had increased caspase-3-like activity and DNA fragmentation, which suggests the occurrence of a type of cell death in M. aeruginosa cells under cold stress similar to programmed cell death. Overall, our fi ndings could confer certain advantages on the Microcystis for surviving cold or dark conditions encountered in the annual cycle, and help explain its repeated occurrence in water blooms in large and shallow lakes.

  6. 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. PMID:26785289

  7. Tracking Down Antibiotic-Resistant Pseudomonas aeruginosa Isolates in a Wastewater Network

    Science.gov (United States)

    Slekovec, Céline; Plantin, Julie; Cholley, Pascal; Thouverez, Michelle; Talon, Daniel; Bertrand, Xavier; Hocquet, Didier

    2012-01-01

    The Pseudomonas aeruginosa-containing wastewater released by hospitals is treated by wastewater treatment plants (WWTPs), generating sludge, which is used as a fertilizer, and effluent, which is discharged into rivers. We evaluated the risk of dissemination of antibiotic-resistant P. aeruginosa (AR-PA) from the hospital to the environment via the wastewater network. Over a 10-week period, we sampled weekly 11 points (hospital and urban wastewater, untreated and treated water, sludge) of the wastewater network and the river upstream and downstream of the WWTP of a city in eastern France. We quantified the P. aeruginosa load by colony counting. We determined the susceptibility to 16 antibiotics of 225 isolates, which we sorted into three categories (wild-type, antibiotic-resistant and multidrug-resistant). Extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs) were identified by gene sequencing. All non-wild-type isolates (n = 56) and a similar number of wild-type isolates (n = 54) were genotyped by pulsed-field gel electrophoresis and multilocus sequence typing. Almost all the samples (105/110, 95.5%) contained P. aeruginosa, with high loads in hospital wastewater and sludge (≥3×106 CFU/l or/kg). Most of the multidrug-resistant isolates belonged to ST235, CC111 and ST395. They were found in hospital wastewater and some produced ESBLs such as PER-1 and MBLs such as IMP-29. The WWTP greatly reduced P. aeruginosa counts in effluent, but the P. aeruginosa load in the river was nonetheless higher downstream than upstream from the WWTP. We conclude that the antibiotic-resistant P. aeruginosa released by hospitals is found in the water downstream from the WWTP and in sludge, constituting a potential risk of environmental contamination. PMID:23284623

  8. Molecular Characterization of Pseudomonas aeruginosa UPM P3 from Oil Palm Rhizosphere

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    Badri F. Azadeh

    2009-01-01

    Full Text Available Problem statement: Pseudomonas aeruginosa has been used in agriculture as biological agents. It has shown substantial control of a variety of soil-borne plant pathogens including Macrophomina phaseolina, Botrytis cinerea, Rhizoctonia solani, Colletotrichum truncatum, Pythium, Fusarium and others. Species aggregate of Pseudomonas aeruginosa strain UPM P3 was shown to have potential as a biocontrol agent against Ganoderma boninense, the causal agent of Basal Stem Rot (BSR of oil palm. However, P. aeruginosa is also an opportunistic pathogen. It typically infects the pulmonary tract, urinary tract, burns, wounds and also causes other blood infections. The objective of this study was to carry out DNA fingerprinting for strain differentiation to differentiate between pathogenic and non-pathogenic forms of P. aeruginosa strain UPM P3. Approach: Genotype characterization was carried out by amplification of the recA gene using specific primers, purified using QIA Quick PCR purification Kit and sent for sequencing. Multiple sequence alignments were performed on the selected closely related sequence accessions using CLUSTAL W software. The recA gene was used for phylogenetic and PCR-RFLP studies. Results: From the phylogenetic tree, UPM P3 has more than 90% similarity with Pseudomonas aeruginosa strains: PAM7, PAO1, UCBPP-PA14 and PA7. UPM P3 was further digested with restriction enzymes; PvuII, BsrI, ZraI, FokI and SgrAI. RFLP results showed that strain UPM P3 has close similarity with strain PAO1 of Pseudomonas aeruginosa. Conclusion: Strain PAO1 is commonly associated with strains of medical, human or plant pathogens and agricultural environment. Common habitats include soil, hosts, aquatic environment and wastewater and also a common contaminant of public places. Thus the use of Pseudomonas aeruginosa strain UPMP3 as a biological control candidate in agriculture has to be monitored.

  9. Regulation and function of versatile aerobic and anaerobic respiratory metabolism in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Hiroyuki eArai

    2011-05-01

    Full Text Available Pseudomonas aeruginosa is a ubiquitously distributed opportunistic pathogen that inhabits soil and water as well as animal-, human-, and plant-host-associated environments. The ubiquity would be attributed to its very versatile energy metabolism. P. aeruginosa has a highly branched respiratory chain terminated by multiple terminal oxidases and denitrification enzymes. Five terminal oxidases for aerobic respiration have been identified in the P. aeruginosa cells. Three of them, the cbb3-1 oxidase, the cbb3-2 oxidase, and the aa3 oxidase, are cytochrome c oxidases and the other two, the bo3 oxidase and the cyanide-insensitive oxidase, are quinol oxidases. Each oxidase has a specific affinity for oxygen, efficiency of energy coupling, and tolerance to various stresses such as cyanide and reactive nitrogen species. These terminal oxidases are used differentially according to the environmental conditions. P. aeruginosa also has a complete set of the denitrification enzymes that reduce nitrate to molecular nitrogen via nitrite, nitric oxide (NO, and nitrous oxide. These nitrogen oxides function as alternative electron acceptors and enable P. aeruginosa to grow under anaerobic conditions. One of the denitrification enzymes, NO reductase, is also expected to function for detoxification of NO produced by the host immune defense system. The control of the expression of these aerobic and anaerobic respiratory enzymes would contribute to the adaptation of P. aeruginosa to a wide range of environmental conditions including in the infected hosts. Characteristics of these respiratory enzymes and the regulatory system that controls the expression of the respiratory genes in the P. aeruginosa cells are overviewed in this article.

  10. Effective removal of Microcystis aeruginosa and microcystin-LR using nanosilicate platelets.

    Science.gov (United States)

    Chang, Shu-Chi; Li, Cheng-Hao; Lin, Jiang-Jen; Li, Yen-Hsien; Lee, Maw-Rong

    2014-03-01

    Drinking water safety has been threatened by increasing harmful algal blooms (HABs) in water sources. HABs are closely associated with eutrophication in freshwater lakes, e.g. Lake Tai in China, and marine environments as well, e.g. Baltic Sea in Europe. Among all HABs, Microcystis aeruginosa attracted much attention due to its easy proliferation and potent toxins, microcystins. Most of the current control technologies can result in immediate release of microcystins which are hard to remove by drinking water treatment processes. Here we propose to simultaneously remove M. aeruginosa and its toxin, microcystin-LR (MC-LR), using nanosilicate platelet (NSP) derived from natural clay mineral. In this study, NSP showed strong selective growth inhibition and good settling enhancing effects on M. aeruginosa and highly efficient removal of MC-LR. NSP can inhibit the growth of M. aeruginosa (initial cell concentration at 3.00×10(6)cellmL(-1)) with a LC50 at 0.28ppm after 12h exposure. At the dosage of 100ppm, NSP can enhance settling of suspended M. aeruginosa. Bacterial growth inhibition tests showed NSP had very mild growth inhibition effects on Escherichia coli at high dosage but promoted the growth of Pseudomonas aeruginosa and Bacillus halodurans. For MC-LR removal, at an initial concentration of 100μgL(-1), NSP achieved higher than 99% removal. Thus, the results suggest that NSP could be an excellent candidate for controlling M. aeruginosa-related HABs in water bodies. PMID:24268348

  11. Functional analysis of the Pseudomonas aeruginosa autoinducer PAI.

    Science.gov (United States)

    Passador, L; Tucker, K D; Guertin, K R; Journet, M P; Kende, A S; Iglewski, B H

    1996-10-01

    A series of structural analogs of the Pseudomonas aeruginosa autoinducer [PAI, N-3-oxo-dodecanoyl homoserine lactone] were obtained and tested for their ability to act as autoinducers in stimulating the expression of the gene for elastase (lasB) by measuring beta-galactosidase production from a lasB-lacZ gene fusion in the presence of the transcriptional activator LasR. The data suggest that the length of the acyl side chain of the autoinducer molecule is the most critical factor for activity. Replacement of the ring O by S in the homoserine lactone moiety can be tolerated. Tritium-labelled PAI ([3H]PAI) was synthesized and used to demonstrate the association of [3H]PAI with cells overexpressing LasR. The PAI analogs were also tested for their ability to compete with [3H]PAI for binding of LasR. Results from the competition assays suggest that once again the length of the acyl side chain appears to be crucial for antagonist activity. The presence of the 3-oxo moiety also plays a significant role in binding since analogs which lacked this moiety were much less effective in blocking binding of [3H]PAI. All analogs demonstrating competition with PAI in binding to LasR also exhibited the ability to activate lasB expression, suggesting that they are functional analogs of PAI. PMID:8830697

  12. Global genotype-phenotype correlations in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Claudia Pommerenke

    Full Text Available Once the genome sequence of an organism is obtained, attention turns from identifying genes to understanding their function, their organization and control of metabolic pathways and networks that determine its physiology. Recent technical advances in acquiring genome-wide data have led to substantial progress in identifying gene functions. However, we still do not know the function of a large number of genes and, even when a gene product has been assigned to a functional class, we cannot normally predict its contribution to the phenotypic behaviour of the cell or organism--the phenome. In this study, we assessed bacterial growth parameters of 4030 non-redundant PA14 transposon mutants in the pathogenic bacterium Pseudomonas aeruginosa. The genome-wide simultaneous analysis of 119 distinct growth-related phenotypes uncovered a comprehensive phenome and provided evidence that most genotypes are not phenotypically isolated but rather define specific complex phenotypic clusters of genotypes. Since phenotypic overlap was demonstrated to reflect the relatedness of genotypes on a global scale, knowledge of an organism's phenome might significantly contribute to the advancement of functional genomics.

  13. Physicochemical properties of elastase isolated from clinical Pseudomonas Aeruginosa

    International Nuclear Information System (INIS)

    Purified elastase was obtained from clinical Pseudomonas Aeruginosa (P.A.-283). The enzyme showed not only elasto lytic activity, but also a broad proteolytic activity against various proteins. The activity of the enzyme on collagen and gelatin was also observed. The optimum pH for elastase was 7.8 to 8.0 for both the proteolytic and elasto lytic activities. The elastase was stable in a pH range from 6.6 to 9.0. Optimum temperature for proteolytic and elasto lytic activities was 40 and inhibition of elastase occurs at 80 . The D10 value of the P.A-283 was found to be 0.11 kGy. Increasing the dose level value of gamma-irradiation decrease the proteolytic activity in the culture filtrate reaching only 16% at the dose level 0.5 kGy. Chelating agents and some metal ions inhibited both proteolytic and elasto lytic activities. Selective inhibition of elasto lytic activity was observed in high concentrations of sodium and ammonium salts without concurrent decrease in the proteolytic activity of the enzyme.4 fig., 3 tab

  14. Electrical conductivity measurements of bacterial nanowires from Pseudomonas aeruginosa

    Science.gov (United States)

    Maruthupandy, Muthusamy; Anand, Muthusamy; Maduraiveeran, Govindhan; Sait Hameedha Beevi, Akbar; Jeeva Priya, Radhakrishnan

    2015-12-01

    The extracellular appendages of bacteria (flagella) that transfer electrons to electrodes are called bacterial nanowires. This study focuses on the isolation and separation of nanowires that are attached via Pseudomonas aeruginosa bacterial culture. The size and roughness of separated nanowires were measured using transmission electron microscopy (TEM) and atomic force microscopy (AFM), respectively. The obtained bacterial nanowires indicated a clear image of bacterial nanowires measuring 16 nm in diameter. The formation of bacterial nanowires was confirmed by microscopic studies (AFM and TEM) and the conductivity nature of bacterial nanowire was investigated by electrochemical techniques. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which are nondestructive voltammetry techniques, suggest that bacterial nanowires could be the source of electrons—which may be used in various applications, for example, microbial fuel cells, biosensors, organic solar cells, and bioelectronic devices. Routine analysis of electron transfer between bacterial nanowires and the electrode was performed, providing insight into the extracellular electron transfer (EET) to the electrode. CV revealed the catalytic electron transferability of bacterial nanowires and electrodes and showed excellent redox activities. CV and EIS studies showed that bacterial nanowires can charge the surface by producing and storing sufficient electrons, behave as a capacitor, and have features consistent with EET. Finally, electrochemical studies confirmed the development of bacterial nanowires with EET. This study suggests that bacterial nanowires can be used to fabricate biomolecular sensors and nanoelectronic devices.

  15. 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

  16. Transcriptome Profiling of Antimicrobial Resistance in Pseudomonas aeruginosa.

    Science.gov (United States)

    Khaledi, Ariane; Schniederjans, Monika; Pohl, Sarah; Rainer, Roman; Bodenhofer, Ulrich; Xia, Boyang; Klawonn, Frank; Bruchmann, Sebastian; Preusse, Matthias; Eckweiler, Denitsa; Dötsch, Andreas; Häussler, Susanne

    2016-08-01

    Emerging resistance to antimicrobials and the lack of new antibiotic drug candidates underscore the need for optimization of current diagnostics and therapies to diminish the evolution and spread of multidrug resistance. As the antibiotic resistance status of a bacterial pathogen is defined by its genome, resistance profiling by applying next-generation sequencing (NGS) technologies may in the future accomplish pathogen identification, prompt initiation of targeted individualized treatment, and the implementation of optimized infection control measures. In this study, qualitative RNA sequencing was used to identify key genetic determinants of antibiotic resistance in 135 clinical Pseudomonas aeruginosa isolates from diverse geographic and infection site origins. By applying transcriptome-wide association studies, adaptive variations associated with resistance to the antibiotic classes fluoroquinolones, aminoglycosides, and β-lactams were identified. Besides potential novel biomarkers with a direct correlation to resistance, global patterns of phenotype-associated gene expression and sequence variations were identified by predictive machine learning approaches. Our research serves to establish genotype-based molecular diagnostic tools for the identification of the current resistance profiles of bacterial pathogens and paves the way for faster diagnostics for more efficient, targeted treatment strategies to also mitigate the future potential for resistance evolution. PMID:27216077

  17. Study on Antibiotic compounds from Pseudomonas aeruginosa NO4 Strain

    International Nuclear Information System (INIS)

    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

  18. Cellular responses of A549 alveolar epithelial cells to serially collected Pseudomonas aeruginosa from cystic fibrosis patients at different stages of pulmonary infection

    DEFF Research Database (Denmark)

    Hawdon, Nicole A; Aval, Pouya Sadeghi; Barnes, Rebecca J;

    2010-01-01

    Pseudomonas aeruginosa is the major cause of chronic pulmonary disease in cystic fibrosis (CF) patients. During chronic infection, P. aeruginosa lose certain virulence factors, transform into a mucoid phenotype, and develop antibiotic resistance. We hypothesized that these genetic and phenotypic...

  19. The susceptibility of Pseudomonas aeruginosa strains from cystic fibrosis patients to bacteriophages.

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    Christiane Essoh

    Full Text Available Phage therapy may become a complement to antibiotics in the treatment of chronic Pseudomonas aeruginosa infection. To design efficient therapeutic cocktails, the genetic diversity of the species and the spectrum of susceptibility to bacteriophages must be investigated. Bacterial strains showing high levels of phage resistance need to be identified in order to decipher the underlying mechanisms. Here we have selected genetically diverse P. aeruginosa strains from cystic fibrosis patients and tested their susceptibility to a large collection of phages. Based on plaque morphology and restriction profiles, six different phages were purified from "pyophage", a commercial cocktail directed against five different bacterial species, including P. aeruginosa. Characterization of these phages by electron microscopy and sequencing of genome fragments showed that they belong to 4 different genera. Among 47 P. aeruginosa strains, 13 were not lysed by any of the isolated phages individually or by pyophage. We isolated two new phages that could lyse some of these strains, and their genomes were sequenced. The presence/absence of a CRISPR-Cas system (Clustered Regularly Interspaced Short Palindromic Repeats and Crisper associated genes was investigated to evaluate the role of the system in phage resistance. Altogether, the results show that some P. aeruginosa strains cannot support the growth of any of the tested phages belonging to 5 different genera, and suggest that the CRISPR-Cas system is not a major defence mechanism against these lytic phages.

  20. Community-based interference against integration of Pseudomonas aeruginosa into human salivary microbial biofilm.

    Science.gov (United States)

    He, X; Hu, W; He, J; Guo, L; Lux, R; Shi, W

    2011-12-01

    As part of the human gastrointestinal tract, the oral cavity represents a complex biological system and harbors diverse bacterial species. Unlike the gut microbiota, which is often considered a health asset, studies of the oral commensal microbiota have been largely limited to their implication in oral conditions such as dental caries and periodontal disease. Less emphasis has been given to their potential beneficial roles, especially the protective effects against oral colonization by foreign or pathogenic bacteria. In this study, we used salivary microbiota derived from healthy human subjects to investigate protective effects against colonization and integration of Pseudomonas aeruginosa, an opportunistic bacterial pathogen, into developing or pre-formed salivary biofilms. When co-cultivated in saliva medium, P. aeruginosa persisted in the planktonic phase, but failed to integrate into the salivary microbial community during biofilm formation. Furthermore, in saliva medium supplemented with sucrose, the oral microbiota inhibited the growth of P. aeruginosa by producing lactic acid. More interestingly, while pre-formed salivary biofilms were able to prevent P. aeruginosa colonization, the same biofilms recovered from mild chlorhexidine gluconate treatment displayed a shift in microbial composition and showed a drastic reduction in protection. Our study indicates that normal oral communities with balanced microbial compositions could be important in effectively preventing the integration of foreign or pathogenic bacterial species, such as P. aeruginosa. PMID:22053962

  1. Occurrence of Microcystis aeruginosa and microcystins in Río de la Plata river (Argentina

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    Darío Andrinolo

    2007-07-01

    Full Text Available This paper is the first report on microcystins producer blooms of Microcystis aeruginosa in the Argentinean coast of the Río de la Plata river, the most important drinking water supply of Argentina. The distribution of toxic cyanobacterium Microcystis cf. aeruginosa blooms in the Argentinean coast of the Rio de la Plata river was studied from December 2003 and January 2006. Microcystis aeruginosa persisted in the river with values ranged between 0 - 7.8 10(4 cells ml-1. Samples of two Microcystis aeruginosa water blooms were collected at La Plata river and were analyzed by the mouse bioassay and by high-performance liquid chromatography with Diode-array and MS detector. The samples showed high hepatotoxicity in mouse bioassay and, in accordance, important amount of microcystins. The bloom samples contained microcystins LR and a variant of microcystin with a molecular ion [M+H]+= 1037.8 m/z as major components. The total toxin content found in these samples was 0.94μg/mg and 0.69μg/mg of lyophilised cells. We conclude that the presence of toxic clones of Microcystis aeruginosa in the Argentinean coast of the Río de la Plata is an actual sanitary and environmental problem and that further studies are necessary to make the risk assessment.

  2. Interclonal gradient of virulence in the Pseudomonas aeruginosa pangenome from disease and environment.

    Science.gov (United States)

    Hilker, Rolf; Munder, Antje; Klockgether, Jens; Losada, Patricia Moran; Chouvarine, Philippe; Cramer, Nina; Davenport, Colin F; Dethlefsen, Sarah; Fischer, Sebastian; Peng, Huiming; Schönfelder, Torben; Türk, Oliver; Wiehlmann, Lutz; Wölbeling, Florian; Gulbins, Erich; Goesmann, Alexander; Tümmler, Burkhard

    2015-01-01

    The population genomics of Pseudomonas aeruginosa was analysed by genome sequencing of representative strains of the 15 most frequent clonal complexes in the P. aeruginosa population and of the five most common clones from the environment of which so far no isolate from a human infection has been detected. Gene annotation identified 5892-7187 open reading frame (ORFs; median 6381 ORFs) in the 20 6.4-7.4 Mbp large genomes. The P. aeruginosa pangenome consists of a conserved core of at least 4000 genes, a combinatorial accessory genome of a further 10 000 genes and 30 000 or more rare genes that are present in only a few strains or clonal complexes. Whole genome comparisons of single nucleotide polymorphism synteny indicated unrestricted gene flow between clonal complexes by recombination. Using standardized acute lettuce, Galleria mellonella and murine airway infection models the full spectrum of possible host responses to P. aeruginosa was observed with the 20 strains ranging from unimpaired health following infection to 100% lethality. Genome comparisons indicate that the differential genetic repertoire of clones maintains a habitat-independent gradient of virulence in the P. aeruginosa population. PMID:25156090

  3. Inflammatory Markers in Cystic Fibrosis Patients with Lung Pseudomonas Aeruginosa Infection

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    A. L. Pukhalsky

    1999-01-01

    Full Text Available Chronic endobronchial inflammation and bacterial infection are the main causes of morbidity and mortality in cystic fibrosis (CF, an autosomal recessive genetic disorder associated with improper function of chloride channels. Inflammation in CF lung is greatly amplified after Pseudomonas aeruginosa infection. In this study the relationship between P. aeruginosa status and inflammatory markers has been investigated. Seventeen CF children in acute lung exacerbation were examined. CF patients without P. aeruginosa infection were characterized by elevated activity of sputum elastase, reduced response of peripheral blood lymphocytes to PHA and significant resistance to the antiproliferative action of glucocorticoids. These parameters were normalized after antibiotic treatment. The patients with prolonged P. aeruginosa infection demonstrated extremely high levels of elastase activity and elevated amounts of sputum IL-8 and TNF-α. Although antibiotic treatment resulted in clinical improvement, it failed to suppress excessive immune response in the lung. The data indicate that CF patients with prolonged P. aeruginosa need the modified treatment, which should include immunomodulating drugs and protease inhibitors as well as antibacterial therapy.

  4. Divergence of a strain of Pseudomonas aeruginosa during an outbreak of ovine mastitis.

    Science.gov (United States)

    Wright, Elli A; Di Lorenzo, Valeria; Trappetti, Claudia; Liciardi, Manuele; Orru, Germano; Viti, Carlo; Bronowski, Christina; Hall, Amanda J; Darby, Alistair C; Oggioni, Marco R; Winstanley, Craig

    2015-01-30

    Bacterial infections causing mastitis in sheep can result in severe economic losses for farmers. A large survey of milk samples from ewes with mastitis in Sardinia, Italy, indicated an increasing prevalence of Pseudomonas aeruginosa infections. It has been shown previously that during chronic, biofilm-associated infections P. aeruginosa populations diversify. We report the phenotypic and genomic characterisation of two clonal P. aeruginosa isolates (PSE305 and PSE306) from a mastitis infection outbreak, representing distinct colony morphology variants. In addition to pigment production, PSE305 and PSE306 differed in phenotypic characteristics including biofilm formation, utilisation of various carbon and nitrogen sources, twitching motility. We found higher levels of expression of genes associated with biofilm formation (pelB) and twitching motility (flgD) in PSE305, compared to the biofilm and twitching-defective PSE306. Comparative genomics analysis revealed single nucleotide polymorphisms (SNPs) and minor insertion/deletion variations between PSE305 and PSE306, including a SNP mutation in the pilP gene of PSE306. By introducing a wild-type pilP gene we were able to partially complement the defective twitching motility of PSE306. There were also three larger regions of difference between the two genomes, indicating genomic instability. Hence, we have demonstrated that P. aeruginosa population divergence can occur during an outbreak of mastitis, leading to significant variations in phenotype and genotype, and resembling the behaviour of P. aeruginosa during chronic biofilm-associated infections. PMID:25475851

  5. Development and evaluation of a new PCR assay for detection of Pseudomonas aeruginosa D genotype.

    Science.gov (United States)

    Lødeng, A G G; Ahlén, C; Lysvand, H; Mandal, L H; Iversen, O J

    2006-08-01

    This report describes a new PCR-based assay for the detection of Pseudomonas aeruginosa genotype D in occupational saturation diving systems in the North Sea. This genotype has persisted in these systems for 11 years (1993-2003) and represents 18% of isolates from infections analysed during this period. The new PCR assay was based on sequences obtained after randomly amplified polymorphic DNA (RAPD)-PCR analysis of a group of isolates related to diving that had been identified previously by pulsed-field gel electrophoresis (PFGE). The primer set for the D genotype targets a gene that codes for a hypothetical class 4 protein in the P. aeruginosa PAO1 genome. A primer set able to detect P. aeruginosa at the species level was also designed, based on the 23S-5S rDNA spacer region. The two assays produced 382-bp and 192-bp amplicons, respectively. The PCR assay was evaluated by analysing 100 P. aeruginosa isolates related to diving, representing 28 PFGE genotypes, and 38 clinical and community P. aeruginosa isolates and strains from other species. The assay identified all of the genotype D isolates tested. Two additional diving-relevant genotypes (TP2 and TP27) were also identified, as well as three isolates of non-diving origin. It was concluded that the new PCR assay is a useful tool for early detection and prevention of infections with the D genotype. PMID:16842571

  6. Antibiotic Resistance Pattern in Pseudomonas Aeruginosa Species Isolated at a Tertiary Care Hospital, Ahmadabad

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    Rajat Rakesh M

    2012-04-01

    Full Text Available Introduction: Pseudomonas aeruginosa (Ps.aeruginosa is one of the important bacterial pathogens isolated from various samples. Despite advances in medical and surgical care and introduction of wide variety of antimicrobial agents against having anti-pseudomonal activities, life threatening infection caused by Ps. aeruginosa continues to cause complications in hospital acquired infections. Several different epidemiological studies indicate that antibiotic resistance is increasing in clinical isolates. Material and Method: This study was conducted during April 2009 to april 2010. During this period total of 630 samples were tested, in which 321 samples showed growth of bacteria. Out of 321 samples, 100 clinical isolates of Pseudomonas aeruginosa were isolated. The samples were selected on the basis of their growth on routine MacConkey medium which showed lactose Non-fermenting pale colonies which were oxidase test positive and on Nutrient agar pigmented and non-pigmented colonies with oxidase positive. Antimicrobial susceptibility of all the isolates was performed by the disc-diffusion (Modified-Kirby Baur disc diffusion method according to CLSIs guidelines. Result: In present study, maximum isolates of Ps. aeruginosa isolated from various samples are resistant to tobramycin (68% followed by gentamycin (63%, piperacillin (50%, ciprofloxacin (49% and ceftazidime (43%. Conclusion: To prevent the spread of the resistant bacteria, it is critically important to have strict antibiotic policies while surveillance programmes for multidrug resistant organisms and infection control procedures need to be implemented. [National J of Med Res 2012; 2(2.000: 156-159

  7. In vitro efficacy of doripenem against pseudomonas aeruginosa and acinetobacter baumannii by e-test

    International Nuclear Information System (INIS)

    To assess the in vitro efficacy of doripenem against Pseudomonas aeruginosa and Acinetobacter baumannii using Epsilometer strips. Study Design: Cross-sectional study. Place and Duration of Study: Department of Microbiology, Army Medical College, Rawalpindi and National University of Sciences and Technology, Islamabad, from May 2014 to September 2014. Methodology: A total of 60 isolates of Acinetobacter baumannii and Pseudomonas aeruginosa collected from various clinical samples received from Military Hospital were included in the study. The specimens were inoculated onto blood, MacConkey and chocolate agars. The isolates were identified using Gram staining, motility, catalase test, oxidase test and API 20NE (Biomeriux, France). Organisms identified as Acinetobacter baumannii and Pseudomonas aeruginosa were included in the study. Bacterial suspensions equivalent to 0.5 McFarland turbidity standard of the isolates were prepared and applied on Mueller Hinton agar. Epsilometer strip was placed in the center of the plate and incubated for 18-24 hours. Minimum Inhibitory Concentration (MIC) was taken to be the point where the epsilon intersected the E-strip. MIC of all the isolates was noted. Results: For Pseudomonas aeruginosa isolates, MIC50 was 12 micro g/mL and MIC90 was 32 micro g/mL. For Acinetobacter baumannii MIC 50 and MIC90 was 32 micro g/mL. Conclusion: Doripenem is no more effective against Pseudomonas aeruginosa and Acinetobacter baumannii in our setting. (author)

  8. Comparison of high-resolution computed tomography findings between Pseudomonas aeruginosa pneumonia and Cytomegalovirus pneumonia

    International Nuclear Information System (INIS)

    To compare pulmonary high-resolution CT (HRCT) findings in patients with Pseudomonas aeruginosa pneumonia to HRCT findings in patients with Cytomegalovirus (CMV) pneumonia. We studied 124 patients (77 men, 47 women; age range, 20-89 years; mean age, 65.4 years) with P. aeruginosa pneumonia and 44 patients (22 men, 22 women; age range, 36-86 years; mean age, 63.2 years) with CMV pneumonia. CT findings of consolidation (p < 0.005), bronchial wall thickening (p < 0.001), cavity (p < 0.05), and pleural effusion (p < 0.001) were significantly more frequent in patients with P. aeruginosa pneumonia than in those with CMV pneumonia. Centrilobular nodules, a crazy-paving appearance, and nodules were significantly more frequent in patients with CMV pneumonia than in those with P. aeruginosa pneumonia (all p < 0.001). Pulmonary HRCT findings, such as bronchial wall thickening, crazy-paving appearance, and nodules may be useful in distinguishing between P. aeruginosa pneumonia and CMV pneumonia. (orig.)

  9. Sensitivity patterns of pseudomonas aeruginosa isolates obtained from clinical specimens in peshawar

    International Nuclear Information System (INIS)

    Pseudomonas aeruginosa (P. aeruginosa) is a highly virulent opportunistic pathogen and a leading cause of nosocomial infections.Affected patients are often hospitalized in an intensive care unit, and are immuno-compromised as a result of disease and treatment. Suspected P. aeruginosa require timely, adequate and empirical antibiotic therapy to ensure improved outcomes. The purpose of the study was to find the sensitivity and resistance pattern of P. aeruginosa to various groups of drugs, in clinical isolates collected from two major tertiary care hospitals of Peshawar. Methods: Different clinical isolate were taken from patients admitted in various wards of Khyber Teaching Hospital and Lady Reading Hospital Peshawar. Results: A total of 258 clinical isolates were positive for P. aeruginosa out of 2058 clinical isolates. Pseudomonas showed high degree of resistance to third generation Cephalosporins (Ceftazidime, and Ceftriaxone) and moderate degree of resistance to Quinolones and Aminoglycosides (Ofloxacin, Ciprofloxacin, Levofloxacin and Amikacin). Low resistance was observed to different combinations (Cefoperazone + Sulbactum, Piperacillin + Tazobactum). Meropenem and Imipenem had negligible resistance. Conclusion: There is growing resistance to different classes of antibiotics. Combination drugs are useful approach for empirical treatment in suspected Pseudomonas infection. Imipenem and Meropenem are extremely effective but should be in reserve. (author)

  10. Recent advances in the treatment of Pseudomonas aeruginosa infections in cystic fibrosis

    Directory of Open Access Journals (Sweden)

    Høiby Niels

    2011-04-01

    Full Text Available Abstract Chronic Pseudomonas aeruginosa lung infection in cystic fibrosis (CF patients is caused by biofilm-growing mucoid strains. Biofilms can be prevented by early aggressive antibiotic prophylaxis or therapy, and they can be treated by chronic suppressive therapy. New results from one small trial suggest that addition of oral ciprofloxacin to inhaled tobramycin may reduce lung inflammation. Clinical trials with new formulations of old antibiotics for inhalation therapy (aztreonam lysine against chronic P. aeruginosa infection improved patient-reported outcome, lung function, time to acute 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 patients without P. aeruginosa infection did not improve lung function. Here I review the recent advances in the treatment of P. aeruginosa lung infections with a focus on inhalation treatments targeted at prophylaxis and chronic suppressive therapy.

  11. Associations among Human-Associated Fecal Contamination, Microcystis aeruginosa, and Microcystin at Lake Erie Beaches.

    Science.gov (United States)

    Lee, Cheonghoon; Marion, Jason W; Cheung, Melissa; Lee, Chang Soo; Lee, Jiyoung

    2015-09-01

    Lake Erie beaches exhibit impaired water quality due to fecal contamination and cyanobacterial blooms, though few studies address potential relationships between these two public health hazards. Using quantitative polymerase chain reaction (qPCR), Microcystis aeruginosa was monitored in conjunction with a human-associated fecal marker (Bacteroides fragilis group; g-Bfra), microcystin, and water quality parameters at two beaches to evaluate their potential associations. During the summer of 2010, water samples were collected 32 times from both Euclid and Villa Angela beaches. The phycocyanin intergenic spacer (PC-IGS) and the microcystin-producing (mcyA) gene in M. aeruginosa were quantified with qPCR. PC-IGS and mcyA were detected in 50.0% and 39.1% of samples, respectively, and showed increased occurrences after mid-August. Correlation and regression analyses showed that water temperature was negatively correlated with M. aeruginosa markers and microcystin. The densities of mcyA and the g-Bfra were predicted by nitrate, implicating fecal contamination as contributing to the growth of M. aeruginosa by nitrate loading. Microcystin was correlated with mcyA (r = 0.413, p < 0.01), suggesting toxin-producing M. aeruginosa populations may significantly contribute to microcystin production. Additionally, microcystin was correlated with total phosphorus (r = 0.628, p < 0.001), which was higher at Euclid (p < 0.05), possibly contributing to higher microcystin concentrations at Euclid. PMID:26378564

  12. Associations among Human-Associated Fecal Contamination, Microcystis aeruginosa, and Microcystin at Lake Erie Beaches

    Directory of Open Access Journals (Sweden)

    Cheonghoon Lee

    2015-09-01

    Full Text Available Lake Erie beaches exhibit impaired water quality due to fecal contamination and cyanobacterial blooms, though few studies address potential relationships between these two public health hazards. Using quantitative polymerase chain reaction (qPCR, Microcystis aeruginosa was monitored in conjunction with a human-associated fecal marker (Bacteroides fragilis group; g-Bfra, microcystin, and water quality parameters at two beaches to evaluate their potential associations. During the summer of 2010, water samples were collected 32 times from both Euclid and Villa Angela beaches. The phycocyanin intergenic spacer (PC-IGS and the microcystin-producing (mcyA gene in M. aeruginosa were quantified with qPCR. PC-IGS and mcyA were detected in 50.0% and 39.1% of samples, respectively, and showed increased occurrences after mid-August. Correlation and regression analyses showed that water temperature was negatively correlated with M. aeruginosa markers and microcystin. The densities of mcyA and the g-Bfra were predicted by nitrate, implicating fecal contamination as contributing to the growth of M. aeruginosa by nitrate loading. Microcystin was correlated with mcyA (r = 0.413, p < 0.01, suggesting toxin-producing M. aeruginosa populations may significantly contribute to microcystin production. Additionally, microcystin was correlated with total phosphorus (r = 0.628, p < 0.001, which was higher at Euclid (p < 0.05, possibly contributing to higher microcystin concentrations at Euclid.

  13. Screening of Molecular Virulence Markers in Staphylococcus aureus and Pseudomonas aeruginosa Strains Isolated from Clinical Infections

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    Veronica Lazar

    2010-12-01

    Full Text Available Staphylococcus (S. aureus and Pseudomonas (Ps. aeruginosa are two of the most frequently opportunistic pathogens isolated in nosocomial infections, responsible for severe infections in immunocompromised hosts. The frequent emergence of antibiotic-resistant S. aureus and Ps. aeruginosa strains has determined the development of new strategies in order to elucidate the different mechanisms used by these bacteria at different stages of the infectious process, providing the scientists with new procedures for preventing, or at least improving, the control of S. aureus and Ps. aeruginosa infections. The purpose of this study was to characterize the molecular markers of virulence in S. aureus and Ps. aeruginosa strains isolated from different clinical specimens. We used multiplex and uniplex PCR assays to detect the genes encoding different cell-wall associated and extracellular virulence factors, in order to evaluate potential associations between the presence of putative virulence genes and the outcome of infections caused by these bacteria. Our results demonstrate that all the studied S. aureus and Ps. aeruginosa strains synthesize the majority of the investigated virulence determinants, probably responsible for different types of infections.

  14. Role of small colony variants in persistence of Pseudomonas aeruginosa infections in cystic fibrosis lungs

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    Malone JG

    2015-07-01

    Full Text Available Jacob G Malone1,21John Innes Centre, Norwich, UK; 2School of Biological Sciences, University of East Anglia, Norwich, UKAbstract: Pseudomonas aeruginosa is an opportunistic pathogen that predominates during the later stages of cystic fibrosis (CF lung infections. Over many years of chronic lung colonization, P. aeruginosa undergoes extensive adaptation to the lung environment, evolving both toward a persistent, low virulence state and simultaneously diversifying to produce a number of phenotypically distinct morphs. These lung-adapted P. aeruginosa strains include the small colony variants (SCVs, small, autoaggregative isolates that show enhanced biofilm formation, strong attachment to surfaces, and increased production of exopolysaccharides. Their appearance in the sputum of CF patients correlates with increased resistance to antibiotics, poor lung function, and prolonged persistence of infection, increasing their relevance as a subject for clinical investigation. The evolution of SCVs in the CF lung is associated with overproduction of the ubiquitous bacterial signaling molecule cyclic-di-GMP, with increased cyclic-di-GMP levels shown to be responsible for the SCV phenotype in a number of different CF lung isolates. Here, we review the current state of research in clinical P. aeruginosa SCVs. We will discuss the phenotypic characteristics underpinning the SCV morphotype, the clinical implications of lung colonization with SCVs, and the molecular basis and clinical evolution of the SCV phenotype in the CF lung environment.Keywords: small colony variants, cystic fibrosis, cyclic-di-GMP, Pseudomonas aeruginosa, RsmA, antibiotics

  15. Platelet 3H-serotonin releasing immune complexes induced by pseudomonas aeruginosa in cystic fibrosis

    International Nuclear Information System (INIS)

    In vitro formation of immune complexes was studied by 3H-serotonin release from human platelets by P. aeruginosa antigens in the presence of serum from 22 cyctic fibrosis patients, chronically infected with mucoid P. aeruginosa (CF+P) and with a pronounced antibody response against these bacteria, and in 24 patients without P. aeruginosa (CF-P). All CF+P patients responded with 3H-serotonin release (16-34%), whereas CF-P patients released less than 15%. In the group of CF+P patients the number of P. aeruginosa precipitins was correlated to the serotonin titer. Time courses indicated that 3H-serotonin release was maximal between 2 and 5 min, and that no further release was observed up to 20 min. There was a gradual increase in 3H-serotonin release with higher platelet concentrations. The response was not changed by complement inactivation, and fractionation of serum demonstrated that the serotonin release was dependent on the presence of the immunoglobulin fraction. These experiments support the suggestion of a type III reaction being involved in the lung damage in CF+P patients and also suggest a possible involvement of serotonin in the inflammatory reaction during chronic P. aeruginosa lung infection. (author)

  16. Identification of Novel Genomic Islands in Liverpool Epidemic Strain of Pseudomonas aeruginosa Using Segmentation and Clustering

    Science.gov (United States)

    Jani, Mehul; Mathee, Kalai; Azad, Rajeev K.

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen implicated in a myriad of infections and a leading pathogen responsible for mortality in patients with cystic fibrosis (CF). Horizontal transfers of genes among the microorganisms living within CF patients have led to highly virulent and multi-drug resistant strains such as the Liverpool epidemic strain of P. aeruginosa, namely the LESB58 strain that has the propensity to acquire virulence and antibiotic resistance genes. Often these genes are acquired in large clusters, referred to as “genomic islands (GIs).” To decipher GIs and understand their contributions to the evolution of virulence and antibiotic resistance in P. aeruginosa LESB58, we utilized a recursive segmentation and clustering procedure, presented here as a genome-mining tool, “GEMINI.” GEMINI was validated on experimentally verified islands in the LESB58 strain before examining its potential to decipher novel islands. Of the 6062 genes in P. aeruginosa LESB58, 596 genes were identified to be resident on 20 GIs of which 12 have not been previously reported. Comparative genomics provided evidence in support of our novel predictions. Furthermore, GEMINI unraveled the mosaic structure of islands that are composed of segments of likely different evolutionary origins, and demonstrated its ability to identify potential strain biomarkers. These newly found islands likely have contributed to the hyper-virulence and multidrug resistance of the Liverpool epidemic strain of P. aeruginosa.

  17. LED array designing and its bactericidal effect researching on Pseudomonas aeruginosa in vitro

    Science.gov (United States)

    Fang, Jing; Xing, Jin; Gao, Liucun; Shen, Benjian; Kang, Hongxiang; Jie, Liang; Peng, Chen

    2015-10-01

    Lights with some special waveband and output power density have a bactericidal effect to some special bacteria. In this paper, the bactericidal effect of light at wavelength of 470 nm on P. aeruginosa (ATCC 27853) is researched with different irradiation dose. The light source is a LED array which is obtained by incoherent combine of 36 LEDs with emitting wavelength of 470 nm. The P. aeruginosa suspension is exposed with the LED array at the light power density of 100 mW/cm2 with exposures time of 0, 5, 10, 20, 40, and 80 min, respectively. The numbers of CFU are then determined by serial dilutions on LB agar plates. The bactericidal effect research results of 470 nm LED on P. aeruginosa show that the killing ratio increases with increasing of the exposure time. For the 80 min irradiation, as much as 92.4% reduction of P. aeruginosa is achieved. The results indicate that, in vitro, 470-nm lights produce dose dependent bactericidal effects on P. aeruginosa.

  18. Rapid detection of Pseudomonas aeruginosa from positive blood cultures by quantitative PCR

    Directory of Open Access Journals (Sweden)

    Cattoir Vincent

    2010-08-01

    Full Text Available Abstract Background Pseudomonas aeruginosa is responsible for numerous bloodstream infections associated with severe adverse outcomes in case of inappropriate initial antimicrobial therapy. The present study was aimed to develop a novel quantitative PCR (qPCR assay, using ecfX as the specific target gene, for the rapid and accurate identification of P. aeruginosa from positive blood cultures (BCs. Methods Over the period August 2008 to June 2009, 100 BC bottles positive for gram-negative bacilli were tested in order to evaluate performances of the qPCR technique with conventional methods as gold standard (i.e. culture and phenotypic identification. Results Thirty-three strains of P. aeruginosa, 53 strains of Enterobactericaeae, nine strains of Stenotrophomonas maltophilia and two other gram-negative species were isolated while 3 BCs were polymicrobial including one mixture containing P. aeruginosa. All P. aeruginosa clinical isolates were detected by qPCR except a single strain in mixed culture. Performances of the qPCR technique were: specificity, 100%; positive predictive value, 100%; negative predictive value, 98.5%; and sensitivity, 97%. Conclusions This reliable technique may offer a rapid (

  19. Comparison of Pseudomonas aeruginosa isolates from mink by serotyping and pulsed-field gel electrophoresis

    DEFF Research Database (Denmark)

    Hammer, Anne Sofie; Pedersen, Karl; Andersen, Thomas Holmen;

    2003-01-01

    Isolates of Pseudomonas aeruginosa from clinical infections in mink were subjected to serotyping and pulsed-field gel electrophoresis (PFGE) using SpeI. A total of 212 isolates of P aeruginosa from the year 1998 to 2001 were included in this study: 168 isolates from mink obtained from 74 farm out...... pathogenic strains of R aeruginosa spread between farms and animals either mechanically, or through feed or water from a common source, rather than by random nosocomial infections with strains from the farm environment.......Isolates of Pseudomonas aeruginosa from clinical infections in mink were subjected to serotyping and pulsed-field gel electrophoresis (PFGE) using SpeI. A total of 212 isolates of P aeruginosa from the year 1998 to 2001 were included in this study: 168 isolates from mink obtained from 74 farm...... outbreaks of haemorrhagic pneumonia. Isolates from mink were separated into 34 distinct clones by PFGE subtyping. All isolates from mink infected during the same farm outbreak were identical, except in one case where two different strains were isolated from mink obtained from the same farm outbreak. R...

  20. Comparison of high-resolution computed tomography findings between Pseudomonas aeruginosa pneumonia and Cytomegalovirus pneumonia

    Energy Technology Data Exchange (ETDEWEB)

    Omeri, Ahmad Khalid; Okada, Fumito; Takata, Shoko; Ono, Asami; Sato, Haruka; Mori, Hiromu [Oita University Faculty of Medicine, Department of Radiology, Yufu, Oita (Japan); Nakayama, Tomoko [Oita Red Cross Hospital, Department of Radiology, Oita (Japan); Ando, Yumiko [Oita Nishibeppu National Hospital, Department of Radiology, Oita (Japan); Hiramatsu, Kazufumi [Oita University Hospital, Hospital Infection Control Center, Oita (Japan)

    2014-12-15

    To compare pulmonary high-resolution CT (HRCT) findings in patients with Pseudomonas aeruginosa pneumonia to HRCT findings in patients with Cytomegalovirus (CMV) pneumonia. We studied 124 patients (77 men, 47 women; age range, 20-89 years; mean age, 65.4 years) with P. aeruginosa pneumonia and 44 patients (22 men, 22 women; age range, 36-86 years; mean age, 63.2 years) with CMV pneumonia. CT findings of consolidation (p < 0.005), bronchial wall thickening (p < 0.001), cavity (p < 0.05), and pleural effusion (p < 0.001) were significantly more frequent in patients with P. aeruginosa pneumonia than in those with CMV pneumonia. Centrilobular nodules, a crazy-paving appearance, and nodules were significantly more frequent in patients with CMV pneumonia than in those with P. aeruginosa pneumonia (all p < 0.001). Pulmonary HRCT findings, such as bronchial wall thickening, crazy-paving appearance, and nodules may be useful in distinguishing between P. aeruginosa pneumonia and CMV pneumonia. (orig.)

  1. A comparative study of coastal and clinical isolates of Pseudomonas aeruginosa

    Science.gov (United States)

    Nair, Anusree V.; Joseph, Neetha; Krishna, Kiran; Sneha, K. G.; Tom, Neenu; Jangid, Kamlesh; Nair, Shanta

    2015-01-01

    Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium having a versatile metabolic potential and great ecological and clinical significance. The geographical distribution of P. aeruginosahas revealed the existence of an unbiased genetic arrangement in terrestrial isolates. In contrast, there are very few reports about P. aeruginosa strains from marine environments. The present work was aimed at studying the distribution of P. aeruginosa in coastal waters along the Indian Peninsula and understanding the environmental influence on genotypic, metabolic and phenotypic characteristics by comparing marine and clinical isolates. Of the 785 marine isolates obtained on selective media, only 32 (~4.1%) were identified as P. aeruginosa, based on their fatty acid methyl ester profiles. A low Euclidian distance value (< 2.5) obtained from chemotaxonomic analysis suggested that all the environmental (coastal and marine) isolates originated from a single species. While UPGMA analyses of AP-PCR and phenotypic profiles separated the environmental and clinical isolates, fatty acid biotyping showed overlapping between most clinical and environmental isolates. Our study revealed the genetic diversity among different environmental isolates of P. aeruginosa. While biogeographical separation was not evident based solely on phenotypic and metabolic typing, genomic and metatranscriptomic studies are more likely to show differences between these isolates. Thus, newer and more insightful methods are required to understand the ecological distribution of this complex group of bacteria. PMID:26413053

  2. Anti-adhesion and antibacterial activity of silver nanoparticles supported on graphene oxide sheets.

    Science.gov (United States)

    de Faria, Andreia Fonseca; Martinez, Diego Stéfani Teodoro; Meira, Stela Maris Meister; de Moraes, Ana Carolina Mazarin; Brandelli, Adriano; Filho, Antonio Gomes Souza; Alves, Oswaldo Luiz

    2014-01-01

    This work reports on the preparation, characterization and antibacterial activity of a nanocomposite formed from graphene oxide (GO) sheets decorated with silver nanoparticles (GO-Ag). The GO-Ag nanocomposite was prepared in the presence of AgNO3 and sodium citrate. The physicochemical characterization was performed by UV-vis spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), Raman spectroscopy and transmission electron microscopy (TEM). The average size of the silver nanoparticles anchored on the GO surface was 7.5 nm. Oxidation debris fragments (a byproduct adsorbed on the GO surface) were found to be crucial for the nucleation and growth of the silver nanoparticles. The antibacterial activity of the GO and GO-Ag nanocomposite against the microorganism Pseudomonas aeruginosa was investigated using the standard counting plate methodology. The GO dispersion showed no antibacterial activity against P. aeruginosa over the concentration range investigated. On the other hand, the GO-Ag nanocomposite displayed high biocidal activity with a minimum inhibitory concentration ranging from 2.5 to 5.0 μg/mL. The anti-biofilm activity toward P. aeruginosa adhered on stainless steel surfaces was also investigated. The results showed a 100% inhibition rate of the adhered cells after exposure to the GO-Ag nanocomposite for one hour. To the best of our knowledge, this work provides the first direct evidence that GO-Ag nanocomposites can inhibit the growth of microbial adhered cells, thus preventing the process of biofilm formation. These promising results support the idea that GO-Ag nanocomposites may be applied as antibacterial coatings material to prevent the development of biofilms in food packaging and medical devices. PMID:24060936

  3. 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

  4. Pseudomonas aeruginosa mutations in lasI and rhlI quorum sensing systems result in milder chronic lung infection

    DEFF Research Database (Denmark)

    Wu, H; Song, Z; Givskov, Michael;

    2001-01-01

    To understand the importance of quorum sensing in chronic Pseudomonas aeruginosa lung infection, the in vivo pathogenic effects of the wild-type P. aeruginosa PAO1 and its double mutant, PAO1 lasI rhlI, in which the signal-generating parts of the quorum sensing systems are defective were compared...

  5. The clonal antibody response to Pseudomonas aeruginosa heat shock protein is highly diverse in cystic fibrosis patients

    DEFF Research Database (Denmark)

    Ulanova, M; Petersen, T D; Ciofu, O;

    1997-01-01

    The GroEL protein of Pseudomonas aeruginosa belongs to the bacterial 60-65 kDa heat shock protein family. A strong antibody response to GroEL has been found in cystic fibrosis (CF) patients with chronic pulmonary infection caused by P. aeruginosa. Clonotypes of IgG1 and IgG2 antibodies against Gro...

  6. Life history responses of Daphnia magna feeding on toxic Microcystis aeruginosa alone and mixed with a mixotrophic Poterioochromonas species

    DEFF Research Database (Denmark)

    Zhang, Xue; Warming, Trine Perlt; Hu, Hong-Ying;

    2009-01-01

    The toxic effects of a mixotrophic golden alga (Poterioochromonas sp. strain ZX1) and a cyanobacterium Microcystis aeruginosa grazed by Poterioochromonas to a cladoceran were investigated through life history experiments using Daphnia magna. Poterioochromonas cultured in two ways (fed M. aeruginosa...

  7. Cis-2-dodecenoic acid signal modulates virulence of Pseudomonas aeruginosa through interference with quorum sensing systems and T3SS

    Science.gov (United States)

    2013-01-01

    Background Cis-2-dodecenoic acid (BDSF) is well known for its important functions in intraspecies signaling in Burkholderia cenocepacia. Previous work has also established an important role of BDSF in interspecies and inter-kingdom communications. It was identified that BDSF modulates virulence of Pseudomonas aeruginosa. However, how BDSF interferes with virulence of P. aeruginosa is still not clear. Results We report here that BDSF mediates the cross-talk between B. cenocepacia and P. aeruginosa through interference with quorum sensing (QS) systems and type III secretion system (T3SS) of P. aeruginosa. Bioassay results revealed that exogenous addition of BDSF not only reduced the transcriptional expression of the regulator encoding gene of QS systems, i.e., lasR, pqsR, and rhlR, but also simultaneously decreased the production of QS signals including 3-oxo-C12-HSL, Pseudomonas quinolone signal (PQS) and C4-HSL, consequently resulting in the down-regulation of biofilm formation and virulence factor production of P. aeruginosa. Furthermore, BDSF and some of its derivatives are also capable of inhibiting T3SS of P. aeruginosa at a micromolar level. Treatment with BDSF obviously reduced the virulence of P. aeruginosa in both HeLa cell and zebrafish infection models. Conclusions These results depict that BDSF modulates virulence of P. aeruginosa through interference with QS systems and T3SS. PMID:24134835

  8. Antibiotic resistance in Pseudomonas aeruginosa strains with increased mutation frequency due to inactivation of the DNA oxidative repair system

    DEFF Research Database (Denmark)

    Mandsberg, Lotte F; Ciofu, Oana; Kirkby, N;

    2009-01-01

    The chronic Pseudomonas aeruginosa infection of the lungs of cystic fibrosis (CF) patients is characterized by the biofilm mode of growth and chronic inflammation dominated by polymorphonuclear leukocytes (PMNs). A high percentage of P. aeruginosa strains show high frequencies of mutations (hyper...

  9. Expression, purification, crystallization and preliminary crystallographic analysis of PA3885 (TpbA) from Pseudomonas aeruginosa PAO1

    OpenAIRE

    Yang, Wen; Li, Kan; Bai, Yuwei; Zhou, Ruimin; Zhou, Weihong; Bartlam, Mark

    2010-01-01

    PA3885 (TpbA), a tyrosine phosphatase, may function as a balancing factor between biofilm formation and motility in the opportunistic pathogen P. aeruginosa. Here, the expression, purification, crystallization and preliminary crystallographic analysis of PA3885 from P. aeruginosa PAO1 are reported.

  10. Inability of Pseudomonas stutzeri denitrification mutants with the phenotype of Pseudomonas aeruginosa to grow in nitrous oxide.

    OpenAIRE

    1985-01-01

    Pseudomonas aeruginosa PAO1 reduced nitrous oxide to dinitrogen but did not grow anaerobically in nitrous oxide. Two transposon insertion Nos- mutants of Pseudomonas stutzeri exhibited the P. aeruginosa phenotype. Growth yield studies demonstrated that nitrous oxide produced in vivo was productively respired, but nitrous oxide supplied exogenously was not. The defect may be in electron transport or in nitrous oxide uptake.

  11. Growth behavior prediction of fresh catfish fillet with Pseudomonas aeruginosa under stresses of allyl isothiocyanate, temperature and modified atmosphere

    Science.gov (United States)

    Pseudomonas aeruginosa, a common spoilage microorganism in fish, grows rapidly when temperature rises above 4 degree C. The combination of allyl isothiocyanate (AIT) and modified atmosphere (MA) was applied and proved to be effective to retard the growth of P. aeruginosa. The objective of this resea...

  12. The Pseudomonas aeruginosa extracellular secondary metabolite, Paerucumarin, chelates iron and is not localized to extracellular membrane vesicles.

    Science.gov (United States)

    Qaisar, Uzma; Kruczek, Cassandra J; Azeem, Muhammed; Javaid, Nasir; Colmer-Hamood, Jane A; Hamood, Abdul N

    2016-08-01

    Proteins encoded by the Pseudomonas aeruginosa pvcA-D operon synthesize a novel isonitrile functionalized cumarin termed paerucumarin. The pvcA-D operon enhances the expression of the P. aeruginosa fimbrial chaperone/usher pathway (cup) genes and this effect is mediated through paerucumarin. Whether pvcA-D and/or paerucumarin affect the expression of other P. aeruginosa genes is not known. In this study, we examined the effect of a mutation in pvcA-D operon the global transcriptome of the P. aeruginosa strain PAO1-UW. The mutation reduced the expression of several ironcontrolled genes including pvdS, which is essential for the expression of the pyoverdine genes. Additional transcriptional studies showed that the pvcA-D operon is not regulated by iron. Exogenously added paerucumarin enhanced pyoverdine production and pvdS expression in PAO1-UW. Iron-chelation experiments revealed that purified paerucumarin chelates iron. However, exogenously added paerucumarin significantly reduced the growth of a P. aeruginosa mutant defective in pyoverdine and pyochelin production. In contrast to other secondary metabolite, Pseudomonas quinolone signal (PQS), paerucumarin is not localized to the P. aeruginosa membrane vesicles. These results suggest that paerucumarin enhances the expression of iron-controlled genes by chelating iron within the P. aeruginosa extracellular environment. Although paerucumarin chelates iron, it does not function as a siderophore. Unlike PQS, paerucumarin is not associated with the P. aeruginosa cell envelope. PMID:27480638

  13. 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 to...

  14. Draft Genome Sequence of an Invasive Multidrug-Resistant Strain, Pseudomonas aeruginosa BK1, Isolated from a Keratitis Patient

    KAUST Repository

    Jeganathan, Lakshmi Priya

    2014-03-27

    Pseudomonas aeruginosa infections are difficult to treat due to the presence of a multitude of virulence factors and antibiotic resistance. Here, we report the draft genome sequence of P. aeruginosa BK1, an invasive and multidrug-resistant strain, isolated from a bacterial keratitis patient in southern India.

  15. Synthesis of silver nanoparticles using plants extract and analysis of their antimicrobial property

    Directory of Open Access Journals (Sweden)

    Peter Logeswari

    2015-05-01

    Full Text Available Plants extract from Ocimum tenuiflorum, Solanum tricobatum, Syzygium cumini, Centella asiatica and Citrus sinensis was used for the synthesis of silver nanoparticles (Ag NPs from silver nitrate solution. Ag NPs were characterized by UV–vis spectrophotometer, X-ray diffractometer (XRD, atomic force microscope (AFM and scanning electron microscope (SEM. The formation and stability of the reduced silver nanoparticles in the colloidal solution were monitored by UV–vis spectrophotometer analysis. The mean particle diameter of silver nanoparticles was calculated from the XRD pattern according to the line width of the plane, refraction peak using the Scherrer’s equation. AFM showed the formation of silver nanoparticle with an average size of 28 nm, 26.5 nm, 65 nm, 22.3 nm and 28.4 nm corresponding to O. tenuiflorum, S. cumini, C. sinensis, S. tricobatum and C. asiatica, respectively. SEM determination of the brown color stable samples showed the formation of silver nanoparticles and well dispersed nanoparticles could be seen in the samples treated with silver nitrate. Antimicrobial activity of the silver bio-nanoparticles was performed by well diffusion method against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae. The highest antimicrobial activity of silver nanoparticles synthesized by S. tricobatum, O. tenuiflorum extracts was found against S. aureus (30 mm and E. coli (30 mm respectively. The Ag NPs synthesized in this process has the efficient antimicrobial activity against pathogenic bacteria. Of these, silver nanoparticles are playing a major role in the field of nanotechnology and nanomedicine.

  16. Complete Genome Sequences of Broad-Host-Range Pseudomonas aeruginosa Bacteriophages ΦR18 and ΦS12-1

    Science.gov (United States)

    Furusawa, Takaaki; Higuchi, Hidetoshi; Usui, Masaru; Maruyama, Fumito; Nakagawa, Ichiro; Yokota, Hiroshi; Tamura, Yutaka

    2016-01-01

    Pseudomonas aeruginosa is an important cause of racehorse keratitis. Bacteriophage therapy has the potential to aid in the prevention and treatment of diseases caused by P. aeruginosa. We present here the complete genome sequences of two phages, ΦR18 and ΦS12-1, which exhibit infectivity for a broad range of P. aeruginosa isolates. PMID:27151780

  17. Applications of medical nanoparticles

    Institute of Scientific and Technical Information of China (English)

    LIU Yuan-gang; WANG Shi-bin; WENG Lian-jin

    2001-01-01

    @@ INTRODUCTION Nanoparticles, for their subcellular size, have been a important carrier in somefields. These fields include pharmacology, food, cosmetic, etc. Here, we focus onpresent applications of nanoparticles in drug carrier and gene carrier.

  18. Pseudomonas aeruginosa adaptation in the nasopharyngeal reservoir leads to migration and persistence in the lungs.

    Science.gov (United States)

    Fothergill, Joanne L; Neill, Daniel R; Loman, Nick; Winstanley, Craig; Kadioglu, Aras

    2014-01-01

    Chronic bacterial infections are a key feature of a variety of lung conditions. The opportunistic bacterium, Pseudomonas aeruginosa, is extremely skilled at both colonizing and persisting in the airways of patients with lung damage. It has been suggested that the upper airways (including the paranasal sinuses and nasopharynx) play an important role as a silent reservoir of bacteria. Over time, P. aeruginosa can adapt to its niche, leading to increased resistance in the face of the immune system and intense therapy regimes. Here we describe a mouse inhalation model of P. aeruginosa chronic infection that can be studied for at least 28 days. We present evidence for adaptation in vivo, in terms of genotype and phenotype including antibiotic resistance. Our data suggest that there is persistence in the upper respiratory tract and that this is key in the establishment of lung infection. This model provides a unique platform for studying evolutionary dynamics and therapeutics. PMID:25179232

  19. Influence of glyphosate in planktonic and biofilm growth of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Ilana Schneider Lima

    2014-09-01

    Full Text Available This study evaluated the impact of different concentrations of glyphosate (Rondup® on planktonic and biofilm growth of P. aeruginosa. Aerobic and anaerobic cultures of P. aeruginosa ATCC®15442 inoculated in MHB + glyphosate (0.845 ppm, 1.690 ppm, 8.45 ppm, 16.90 ppm, 84.50 ppm, 169 ppm, 845 ppm, and 1690 ppm and cultured in normoxia and anoxia, following their OD560nm every hour for 24 h. Biofilms of adapted cells were formed in the presence of glyphosate (0.845 to 1690 ppm in normoxia and anoxia for 36 h. Glyphosate at concentrations higher than 84.5 ppm reduces the cell density of planktonic aerobic cultures (p 0.05, and more pronounced over 169 ppm. Anaerobic biofilms have their growth more readily favored (p < 0.05, regardless of concentration. In a concentration-dependent manner, glyphosate interferes with the growth ability of P. aeruginosa ATCC®15442.

  20. Phage Therapy: a Step Forward in the Treatment of Pseudomonas aeruginosa Infections

    Science.gov (United States)

    Pires, Diana P.; Vilas Boas, Diana; Sillankorva, Sanna

    2015-01-01

    Antimicrobial resistance constitutes one of the major worldwide public health concerns. Bacteria are becoming resistant to the vast majority of antibiotics, and nowadays, a common infection can be fatal. To address this situation, the use of phages for the treatment of bacterial infections has been extensively studied as an alternative therapeutic strategy. Since Pseudomonas aeruginosa is one of the most common causes of health care-associated infections, many studies have reported the in vitro and in vivo antibacterial efficacy of phage therapy against this bacterium. This review collects data of all the P. aeruginosa phages sequenced to date, providing a better understanding about their biodiversity. This review further addresses the in vitro and in vivo results obtained by using phages to treat or prevent P. aeruginosa infections as well as the major hurdles associated with this therapy. PMID:25972556

  1. Identification of KPC-Producing Pseudomonas Aeruginosa and Acinetobacter Baumanniiin a Burned Infant: A Case Report

    Directory of Open Access Journals (Sweden)

    Abdolaziz Rastegar Lari

    2012-03-01

    Full Text Available The objective of this study was to determine the phenotypic characteristics of KPC-producing Pseudomonas aeruginosa and Acinetobacter baumannii isolates. A case report study was performed at a tertiary burn care centre in Tehran, Iran. Nine isolates of Pseudomonas aeruginosa and Acinetobacter baumannii from a hospitalized case were isolated. The identity of isolates was confirmed and their antibiotic susceptibility testing was performed. Eight out of nine Pseudomonas aeruginosa and Acinetobacter baumannii isolates were resistant to Imipenem. Three out of 8 imipenem resistant isolates were also positive for KPC test. Findings of this study highlight the importance of implementation of an effective infection control strategy in order to prevent and reduce the emergence and spread of gram negative Carbapenemase-producing organisms in Iran.

  2. High genetic diversity among Pseudomonas aeruginosa and Acinetobacter spp. isolated in a public hospital in Brazil

    Directory of Open Access Journals (Sweden)

    Vera Lúcia Dias Siqueira

    2013-03-01

    Full Text Available In Brazil and other regions of the world, Pseudomonas aeruginosa and Acinetobacter spp. have emerged as important agents of nosocomial infection and are commonly involved in outbreaks. The main objective of the present study was to evaluate the genetic relationship among P. aeruginosa and Acinetobacter spp. isolated from patients in a public university hospital in northwestern Paraná, Brazil, and report their antimicrobial resistance profile. A total of 75 P. aeruginosa and 94 Acinetobacter spp. isolates were phenotypically identified and tested for antibiotic susceptibility using automated methodology. Polymyxin B was tested by disk diffusion for P. aeruginosa. Metallo-β-lactamase (MBL was detected using a disk approximation test. Genotyping was performed using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR. Approximately 55% of the P. aeruginosa isolates and 92% of the Acinetobacter spp. isolates were multiresistant, but none were MBL-producers. ERIC-PCR revealed the presence of small clusters of carbapenem-resistant Acinetobacter spp., most likely OXA-type carbapenemase producers. Furthermore, high genetic diversity in P. aeruginosa and Acinetobacter spp. clinical isolates was observed, suggesting that cross-transmission is not very frequent in the studied hospital.No Brasil, bem como em outras regiões do mundo, Pseudomonas aeruginosa e Acinetobacter spp. surgiram como importantes agentes de infecção nosocomial e são comumente envolvidos em surtos. O objetivo principal deste estudo foi descrever a relação genética de P. aeruginosa e Acinetobacter spp. isoladas de pacientes internados em hospital universitário público do noroeste do Paraná - Brasil e reportar o perfil de resistência dessas bactérias. Um total de 75 P. aeruginosa e 94 Acinetobacter spp. isolados foi fenotipicamente identificado e testado para a suscetibilidade aos antibióticos por metodologia automatizada. A polimixina B foi

  3. Pseudomonas aeruginosa Evolutionary Adaptation and Diversification in Cystic Fibrosis Chronic Lung Infections.

    Science.gov (United States)

    Winstanley, Craig; O'Brien, Siobhan; Brockhurst, Michael A

    2016-05-01

    Pseudomonas aeruginosa populations undergo a characteristic evolutionary adaptation during chronic infection of the cystic fibrosis (CF) lung, including reduced production of virulence factors, transition to a biofilm-associated lifestyle, and evolution of high-level antibiotic resistance. Populations of P. aeruginosa in chronic CF lung infections typically exhibit high phenotypic diversity, including for clinically important traits such as antibiotic resistance and toxin production, and this diversity is dynamic over time, making accurate diagnosis and treatment challenging. Population genomics studies reveal extensive genetic diversity within patients, including for transmissible strains the coexistence of highly divergent lineages acquired by patient-to-patient transmission. The inherent spatial structure and spatial heterogeneity of selection in the CF lung appears to play a key role in driving P. aeruginosa diversification. PMID:26946977

  4. Production of Biosurfactant by Pseudomonas aeruginosa Grown on Cashew Apple Juice

    Science.gov (United States)

    Rocha, Maria V. P.; Souza, Maria C. M.; Benedicto, Sofia C. L.; Bezerra, Márcio S.; Macedo, Gorete R.; Saavedra Pinto, Gustavo A.; Gonçalves, Luciana R. B.

    In this work, the ability of biosurfactant production by Pseudomonas aeruginosa in batch cultivation using cashew apple juice (CAJ) and mineral media was evaluated. P. aeruginosa was cultivated in CAJ, which was supplemented with peptone (5.0 g/L) and nutritive broth. All fermentation assays were performed in Erlenmeyer flasks containing 300 mL, incubated at 30°C and 150 rpm. Cell growth (biomass and cell density), pH, and superficial tension were monitored vs time. Surface tension was reduced by 10.58 and 41% when P. aeruginosa was cultivated in nutrient broth and CAJ supplemented with peptone, respectively. These results indicated that CAJ is an adequate medium for growth and biosurfactant production. Best results of biosurfactant production were obtained when CAJ was supplemented with peptone.

  5. Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa biofilm

    DEFF Research Database (Denmark)

    Argyraki, Aikaterini; Markvart, M.; Nielsen, Anne; Bjarnsholt, T.; Bjørndal, L.; Petersen, Paul Michael

    2016-01-01

    skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation......Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas aeruginosa (P. aeruginosa) is a common bacterium that can cause......, on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose...

  6. Survival trends of Staphylococcus aureus, Pseudomonas aeruginosa, and Clostridium perfringens in a sandy South Florida beach

    International Nuclear Information System (INIS)

    The search for alternative indicators of disease-risk from non-enteric pathogens at the beach revealed high densities of targeted bacteria. To explain the high numbers of potential non-enteric pathogens, Staphylococcus aureus and Pseudomonas aeruginosa, in beach sand, we investigated factors affecting their survival and distribution, as well as those of a potential fecal indicator, Clostridium perfringens. Results indicated greater S. aureus and P. aeruginosa survival and proliferation in sterile beach sand, than seawater, with diminished numbers upon exposure to natural micro-predators. C. perfringens remained relatively consistent with initial numbers. Intermediate sand particles (850 μm–2 mm) constituted the major micro-niche; creating implications for beach classification programs. Colonization of sterile sand boxes at the beach by S. aureus and P. aeruginosa confirmed the filtering action (>100×) of beach sand. The use of these potential pathogens in periodic sanitary evaluation of beach sand quality is indicated, regardless of the factors influencing their abundance.

  7. Prevalence of carbapenem resistant Pseudomonas aeruginosa and Acinetobacter baumannii in high complexity hospital

    Directory of Open Access Journals (Sweden)

    Ana Milda Karsten Baumgart

    2010-10-01

    Full Text Available Pseudomonas aeruginosa and Acinetobacter baumannii are Gram-negative bacilli that in the last decades have become prevalent agents of hospital infection due to high antimicrobial resistance developed by these microorganisms. The present study is a retrospective analysis of all positive cultures for these microorganisms in the period of January 2004 to December 2008. Resistance levels of A. baumannii and P. aeruginosa to carbapenems was high and showed a trend to increase during the period of study. In recent years the increasing incidence and resistance levels of A. baumannii and P. aeruginosa to the antimicrobials used for their treatment in the hospital setting underscores the relevance of infections caused by these bacteria. The selective pressure caused by indiscriminated use of broad-spectrum antibiotics in empirical hospital infections is probably the main reason for such an increase with the consequent impact upon patient morbidity and mortality

  8. HD-GYP domain proteins regulate biofilm formation and virulence in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Ryan, Robert P.; Lucey, Jean; O'Donovan, Karen;

    2009-01-01

    residues (YN-GYP). Here we have investigated the role of these proteins in biofilm formation, virulence factor synthesis and virulence of P. aeruginosa. Mutation of PA4108 and PA4781 led to an increase in the level of cyclic-di-GMP in P. aeruginosa, consistent with the predicted activity of the encoded...... proteins as cyclic-di-GMP phosphodiesterases. Mutation of both genes led to reduced swarming motility but had differing effects on production of the virulence factors pyocyanin, pyoverdin and ExoS. Mutation of PA2572 had no effect on cyclic-di-GMP levels and did not influence swarming motility. However, PA......2572 had a negative influence on swarming that was cryptic and was revealed only after removal of an uncharacterized C-terminal domain. Mutation of PA4108, PA4781 and PA2572 had distinct effects on biofilm formation and architecture of P. aeruginosa. All three proteins contributed to virulence of P...

  9. Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa biofilm

    DEFF Research Database (Denmark)

    Argyraki, Aikaterini; Markvart, M.; Nielsen, Anne; Bjarnsholt, T.; Bjørndal, L.; Petersen, Paul Michael

    2016-01-01

    , on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose......Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas aeruginosa (P. aeruginosa) is a common bacterium that can cause...... skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation...

  10. 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

    by the use of peptide nucleic acid-based fluorescence in situ hybridization and confocal laser scanning microscopy (CLSM). We acquired CLSM images of multiple regions in multiple sections cut from five wounds containing P. aeruginosa and five wounds containing S. aureus and measured the distance...... of the bacterial aggregates to the wound surface. The distance of the P. aeruginosa aggregates to the wound surface was significantly greater than that of the S. aureus aggregates, suggesting that the distribution of the bacteria in the chronic wounds was nonrandom. The results are discussed in relation to our......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...

  11. Structure of the T6SS lipoprotein TssJ1 from Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    The crystal structure of the type VI secretion-system protein TssJ1 from P. aeruginosa was solved by iodide SAD at a resolution of 1.4 Å. The type VI secretion system of Pseudomonas aeruginosa has been shown to be responsible for the translocation of bacteriolytic effectors into competing bacteria. A mechanistic understanding of this widely distributed secretion system is developing and structural studies of its components are ongoing. Two representative structures of one highly conserved component, TssJ, from Escherichia coli and Serratia marcescens have been published. Here, the X-ray crystal structure of TssJ1 from P. aeruginosa is presented at 1.4 Å resolution. The overall structure is conserved among the three proteins. This finding suggests that the homologues function in a similar manner and bolsters the understanding of the structure of this family of proteins

  12. Involvement of bacterial migration in the development of complex multicellular structures in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Klausen, Mikkel; Aaes-Jorgensen, A.; Molin, Søren; Tolker-Nielsen, Tim

    2003-01-01

    Detailed knowledge of the developmental process from single cells scattered on a surface to complex multicellular biofilm structures is essential in order to create strategies to control biofilm development. In order to study bacterial migration patterns during Pseudomonas aeruginosa biofilm...... development, we have performed an investigation with time-lapse confocal laser scanning microscopy of biofilms formed by various combinations of colour-coded P. aeruginosa wild type and motility mutants. We show that mushroom-shaped multicellular structures in P. aeruginosa biofilms can form in a sequential...... process involving a non-motile bacterial subpopulation and a migrating bacterial subpopulation. The non-motile bacteria form the mushroom stalks by growth in certain foci of the biofilm. The migrating bacteria form the mushroom caps by climbing the stalks and aggregating on the tops in a process which is...

  13. Biofilm formation by Pseudomonas aeruginosa wild type, flagella and type IV pili mutants

    DEFF Research Database (Denmark)

    Klausen, M.; Heydorn, Arne; Ragas, Paula Cornelia; Lambertsen, Lotte Munch; Aaes-Jorgensen, A.; Molin, Søren; Tolker-Nielsen, Tim

    2003-01-01

    for P. aeruginosa initial attachment or biofilm formation, but the cell appendages had roles in biofilm development, as wild type, flagella and type IV pili mutants formed biofilms with different structures. Dynamics and selection during biofilm formation were investigated by tagging the wild type and...... flagella/type IV mutants with Yfp and Cfp and performing time-lapse confocal laser scanning microscopy in mixed colour biofilms. The initial microcolony formation occurred by clonal growth, after which wild-type P. aeruginosa bacteria spread over the substratum by means of twitching motility. The wild......-type biofilms were dynamic compositions with extensive motility, competition and selection occurring during development. Bacterial migration prevented the formation of larger microcolonial structures in the wild-type biofilms. The results are discussed in relation to the current model for P. aeruginosa biofilm...

  14. Treatment of Pseudomonas aeruginosa-infected orthopedic prostheses with ceftazidime-ciprofloxacin antibiotic combination.

    Science.gov (United States)

    Brouqui, P; Rousseau, M C; Stein, A; Drancourt, M; Raoult, D

    1995-11-01

    Indwelling device infections are associated with considerable morbidity and extremely high cost. Pseudomonas aeruginosa is the most frequent gram-negative etiologic agent associated with infections of indwelling catheters and foreign body implants. It is generally agreed that eradication of infection in the presence of a foreign body requires removal of the foreign body. Using a combination of ceftazidime and ciprofloxacin, we cured nine of nine patients with P. aeruginosa-infected osteosynthetic material and four of five patients with hip and knee prostheses without removing the foreign material. Follow-up was for a mean of 21 months (range, 6 to 60 months). Some patients experienced minor side effects (arthralgia in one patient and rash in another patient). We conclude that this combination is effective and safe and should be useful in the treatment of P. aeruginosa-infected orthopedic implants. PMID:8585720

  15. 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.

  16. Reexamining intra and extracellular metabolites produced by Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    Maria Shuja; Nazia Jamil

    2016-01-01

    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 Gram-positive and Gram-negative; cocci and rods. In case of heavy metal (ZnO and Zn3(PO4)2.4H2O) solubilization, 54 strains solubilized ZnO and 23 strains solubilized Zn3(PO4)2.4H2O, 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.

  17. Recombinant Expression Screening of P. aeruginosa Bacterial Inner Membrane Proteins

    Directory of Open Access Journals (Sweden)

    Jeffery Constance J

    2010-11-01

    Full Text Available Abstract Background Transmembrane proteins (TM proteins make up 25% of all proteins and play key roles in many diseases and normal physiological processes. However, much less is known about their structures and molecular mechanisms than for soluble proteins. Problems in expression, solubilization, purification, and crystallization cause bottlenecks in the characterization of TM proteins. This project addressed the need for improved methods for obtaining sufficient amounts of TM proteins for determining their structures and molecular mechanisms. Results Plasmid clones were obtained that encode eighty-seven transmembrane proteins with varying physical characteristics, for example, the number of predicted transmembrane helices, molecular weight, and grand average hydrophobicity (GRAVY. All the target proteins were from P. aeruginosa, a gram negative bacterial opportunistic pathogen that causes serious lung infections in people with cystic fibrosis. The relative expression levels of the transmembrane proteins were measured under several culture growth conditions. The use of E. coli strains, a T7 promoter, and a 6-histidine C-terminal affinity tag resulted in the expression of 61 out of 87 test proteins (70%. In this study, proteins with a higher grand average hydrophobicity and more transmembrane helices were expressed less well than less hydrophobic proteins with fewer transmembrane helices. Conclusions In this study, factors related to overall hydrophobicity and the number of predicted transmembrane helices correlated with the relative expression levels of the target proteins. Identifying physical characteristics that correlate with protein expression might aid in selecting the "low hanging fruit", or proteins that can be expressed to sufficient levels using an E. coli expression system. The use of other expression strategies or host species might be needed for sufficient levels of expression of transmembrane proteins with other physical

  18. Formation of THMs and HANs during bromination of Microcystis aeruginosa

    Institute of Scientific and Technical Information of China (English)

    Yunzhu Pu; Lingzhao Kong; Xin Huang; Guoji Ding; Naiyun Gao

    2013-01-01

    Bromine-contained disinfectants and biocides are widely used in swimming pools,recreational waters and cooling towers.The objective of this study was to evaluate the formation of thrihalomethanes (THMs) and haloacetonitriles (HANs) and their cytotoxicity in algae solutions during free bromine disinfection.Disinfection by-products formation potential experiments were conducted using modelsolutions containing 7mg/L (as total organic carbon) Microcystis aeruginosa cells.Effects of free bromine dosage,pH and ammonia were investigated.The results showed that brominated disinfection by-products were the major products when free bromine was applied.The total THMs formed during bromination was much as that formed during chlorination,whereas HANs were elevated by using bromination instead of chlorination.Dibromoacetonitrice (C2H2NBr2) and bromoform (CHBr3) were the only detected species during free bromine disinfection.The production of C2H2NBr2 and CHBr3 increased with disinfectant dosage but decreased with dosing ammonia.CHBr3 increased with the pH changing from 5 to 9.However,C2H2NBr2 achieved the highest production at neutral pH,which was due to a joint effect of variation in hydrolysis rate and free bromine reactivity.The hydrolysis of C2H2NBr2 was basecatalytic and nearly unaffected by disinfectant.Finally,estimation of cytotoxicity of the disinfected algae solutions showed that HANs formation was responsible for the majority of toxicity.Considering its highest toxicity among the measured disinfection by-products,the elevated C2H2NBr2 should be considered when using bromine-related algaecide.

  19. Kinetic characterisation of arylamine N-acetyltransferase from Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Sim Edith

    2007-03-01

    Full Text Available Abstract Background Arylamine N-acetyltransferases (NATs are important drug- and carcinogen-metabolising enzymes that catalyse the transfer of an acetyl group from a donor, such as acetyl coenzyme A, to an aromatic or heterocyclic amine, hydrazine, hydrazide or N-hydroxylamine acceptor substrate. NATs are found in eukaryotes and prokaryotes, and they may also have an endogenous function in addition to drug metabolism. For example, NAT from Mycobacterium tuberculosis has been proposed to have a role in cell wall lipid biosynthesis, and is therefore of interest as a potential drug target. To date there have been no studies investigating the kinetic mechanism of a bacterial NAT enzyme. Results We have determined that NAT from Pseudomonas aeruginosa, which has been described as a model for NAT from M. tuberculosis, follows a Ping Pong Bi Bi kinetic mechanism. We also describe substrate inhibition by 5-aminosalicylic acid, in which the substrate binds both to the free form of the enzyme and the acetyl coenzyme A-enzyme complex in non-productive reaction pathways. The true kinetic parameters for the NAT-catalysed acetylation of 5-aminosalicylic acid with acetyl coenzyme A as the co-factor have been established, validating earlier approximations. Conclusion This is the first reported study investigating the kinetic mechanism of a bacterial NAT enzyme. Additionally, the methods used herein can be applied to investigations of the interactions of NAT enzymes with new chemical entities which are NAT ligands. This is likely to be useful in the design of novel potential anti-tubercular agents.

  20. The Formation of Biofilms by Pseudomonas aeruginosa: A Review of the Natural and Synthetic Compounds Interfering with Control Mechanisms

    Directory of Open Access Journals (Sweden)

    Tsiry Rasamiravaka

    2015-01-01

    Full Text Available P. aeruginosa is an opportunistic pathogenic bacterium responsible for both acute and chronic infections. Beyond its natural resistance to many drugs, its ability to form biofilm, a complex biological system, renders ineffective the clearance by immune defense systems and antibiotherapy. The objective of this report is to provide an overview (i on P. aeruginosa biofilm lifestyle cycle, (ii on the main key actors relevant in the regulation of biofilm formation by P. aeruginosa including QS systems, GacS/GacA and RetS/LadS two-component systems and C-di-GMP-dependent polysaccharides biosynthesis, and (iii finally on reported natural and synthetic products that interfere with control mechanisms of biofilm formation by P. aeruginosa without affecting directly bacterial viability. Concluding remarks focus on perspectives to consider biofilm lifestyle as a target for eradication of resistant infections caused by P. aeruginosa.