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Sample records for aeruginosa requiring removal

  1. 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

  2. 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...

  3. 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

  4. Bisphenol A removal by a Pseudomonas aeruginosa immobilized on granular activated carbon and operating in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mita, Luigi [National Laboratory on Endocrine Disruptors, National Institute of Biostructures and Biosystems (INBB), Via P. Castellino, 111, 80131 Naples (Italy); Institute of Genetic and Biophysics “ABT”, Via P. Castellino, 111, 80131 Naples Italy (Italy); Grumiro, Laura [National Laboratory on Endocrine Disruptors, National Institute of Biostructures and Biosystems (INBB), Via P. Castellino, 111, 80131 Naples (Italy); Rossi, Sergio [Institute of Genetic and Biophysics “ABT”, Via P. Castellino, 111, 80131 Naples Italy (Italy); Bianco, Carmen; Defez, Roberto [Institute of Biosciences and BioResources, Via P. Castellino, 111, 80131 Naples (Italy); Gallo, Pasquale [Dipartimento di Chimica, Istituto Zooprofilattico Sperimentale del Mezzogiorno, Via della Salute 2, 80055 Portici, Naples (Italy); Mita, Damiano Gustavo, E-mail: mita@igb.cnr.it [National Laboratory on Endocrine Disruptors, National Institute of Biostructures and Biosystems (INBB), Via P. Castellino, 111, 80131 Naples (Italy); Institute of Genetic and Biophysics “ABT”, Via P. Castellino, 111, 80131 Naples Italy (Italy); Diano, Nadia [National Laboratory on Endocrine Disruptors, National Institute of Biostructures and Biosystems (INBB), Via P. Castellino, 111, 80131 Naples (Italy); Department of Experimental Medicine, Second University of Naples, Via S.M. di Costantinopoli, 16, 80138 Naples Italy (Italy)

    2015-06-30

    Highlights: • A fluidized bed reactor, filled with a Pseudomonas aeruginosa immobilized on GAC, has been used for BPA removal. • BPA removal resulted from a biological activated carbon (BAC) process. • Equations describing the results have been indicated. • BPA removal was analyzed as a function of time and biofilm reuse. - Abstract: Serratia rubidiae, Pseudomonas aeruginosa and Escherichia coli K12 have been studied for their ability of Bisphenol A removal from aqueous systems and biofilm formation on activated granule carbon. Mathematical equations for biodegradation process have been elaborated and discussed. P. aeruginosa was found the best strain to be employed in the process of Bisphenol A removal. The yield in BPA removal of a P. aeruginosa biofilm grown on GAC and operating in a fluidized bed reactor has been evaluated. The results confirm the usefulness in using biological activated carbon (BAC process) to remove phenol compounds from aqueous systems.

  5. Bisphenol A removal by a Pseudomonas aeruginosa immobilized on granular activated carbon and operating in a fluidized bed reactor

    International Nuclear Information System (INIS)

    Highlights: • A fluidized bed reactor, filled with a Pseudomonas aeruginosa immobilized on GAC, has been used for BPA removal. • BPA removal resulted from a biological activated carbon (BAC) process. • Equations describing the results have been indicated. • BPA removal was analyzed as a function of time and biofilm reuse. - Abstract: Serratia rubidiae, Pseudomonas aeruginosa and Escherichia coli K12 have been studied for their ability of Bisphenol A removal from aqueous systems and biofilm formation on activated granule carbon. Mathematical equations for biodegradation process have been elaborated and discussed. P. aeruginosa was found the best strain to be employed in the process of Bisphenol A removal. The yield in BPA removal of a P. aeruginosa biofilm grown on GAC and operating in a fluidized bed reactor has been evaluated. The results confirm the usefulness in using biological activated carbon (BAC process) to remove phenol compounds from aqueous systems

  6. Removal of Cr(VI from aqueous solution using Bacillus subtilis, Pseudomonas aeruginosa and Enterobacter cloacae

    Directory of Open Access Journals (Sweden)

    P. Sethuraman,

    2010-06-01

    Full Text Available The objective of this study is to investigate the removal efficiency of Cr(VI by Bacillus subtilis, Pseudomonas aeruginosa and Enterobacter cloacae from aqueous solution under different process conditions. Batch mode experiments were carried out as a function of solution pH, biosorbent dosage, Cr(VI concentration and contact time.The FT-IR spectra and SEM analysis of the biosorbent were recorded to analyse the number and position of the functional groups available for the binding of Cr(VI ions and to study the morphology of biosorbent. The batch isothermal equilibrium data were analyzed with Freundlich and Langmuir isotherm models. The kinetic models were examined with pseudo first order and pseudo second order kinetics. The results revealed that the Cr(VI is considerably adsorbed on bacterial biomass and it could be an economical method for the removal of Cr(VI from aqueous solution.

  7. Microcystin-LR removal from Microcystis aeruginosa using in natura sugarcane bagasse and activated carbon

    Directory of Open Access Journals (Sweden)

    Aline Rafaela de Almeida

    2016-03-01

    Full Text Available Microcystin-LR is a type of toxin released by the Microcystis aeruginosa cyanobacteria found in water sources used for human consumption. It can cause illness and even death if not completely removed in conventional water treatment. The retention of this toxin is often accomplished by the adsorption process in activated carbon in water treatment plants. In this study, a comparison was made between the retention of microcystin-LR by activated carbon and by sugarcane bagasse in natura applied as a bio-adsorbent. Adsorption experiments were performed after the physical and chemical properties of the bio adsorbent and the activated carbon were characterized. The adsorption performance was evaluated by the toxin removal efficiency and the maximum adsorption capacity. Average removal efficiencies of the toxin resulted in 65.25; 41.74 and 11.75% for the activated carbon and 24.15; 18.92 and 12.27% for the sugarcane bagasse for concentrations of 2.36, 3.33 and 3.83 µg L-1, respectively. The bio adsorbent presented removal efficiency for the toxin similar to that observed in the activated carbon for the concentration of 3.83 µg L-1. Maximum adsorption capacity obtained with better linear adjustment to the Freundlich isotherm was 6,047.84 µg g-1 (toxin concentration of 3.83 µg L-1 for sugarcane bagasse and 338.61 µg g-1 (toxin concentration of 2.36 µg L-1 for activated carbon.

  8. Structure of the autoinducer required for expression of Pseudomonas aeruginosa virulence genes.

    OpenAIRE

    Pearson, J P; Gray, K. M.; Passador, L.; Tucker, K D; Eberhard, A.; Iglewski, B H; Greenberg, E P

    1994-01-01

    In Pseudomonas aeruginosa the LasR protein is required for activation of lasB and several other virulence genes. A diffusible signal molecule, the P. aeruginosa autoinducer (PAI), produced by the bacterial cell and released into the growth medium, is required for activity of LasR. By cloning a lasB::lacZ fusion and a lasR gene under control of the lac promoter in Escherichia coli, we have developed a quantitative bioassay for PAI. We have used this assay to follow the purification of PAI from...

  9. Requirements for Pseudomonas aeruginosa acute burn and chronic surgical wound infection.

    Directory of Open Access Journals (Sweden)

    Keith H Turner

    2014-07-01

    Full Text Available Opportunistic infections caused by Pseudomonas aeruginosa can be acute or chronic. While acute infections often spread rapidly and can cause tissue damage and sepsis with high mortality rates, chronic infections can persist for weeks, months, or years in the face of intensive clinical intervention. Remarkably, this diverse infectious capability is not accompanied by extensive variation in genomic content, suggesting that the genetic capacity to be an acute or a chronic pathogen is present in most P. aeruginosa strains. To investigate the genetic requirements for acute and chronic pathogenesis in P. aeruginosa infections, we combined high-throughput sequencing-mediated transcriptome profiling (RNA-seq and genome-wide insertion mutant fitness profiling (Tn-seq to characterize gene expression and fitness determinants in murine models of burn and non-diabetic chronic wound infection. Generally we discovered that expression of a gene in vivo is not correlated with its importance for fitness, with the exception of metabolic genes. By combining metabolic models generated from in vivo gene expression data with mutant fitness profiles, we determined the nutritional requirements for colonization and persistence in these infections. Specifically, we found that long-chain fatty acids represent a major carbon source in both chronic and acute wounds, and P. aeruginosa must biosynthesize purines, several amino acids, and most cofactors during infection. In addition, we determined that P. aeruginosa requires chemotactic flagellar motility for fitness and virulence in acute burn wound infections, but not in non-diabetic chronic wound infections. Our results provide novel insight into the genetic requirements for acute and chronic P. aeruginosa wound infections and demonstrate the power of using both gene expression and fitness profiling for probing bacterial virulence.

  10. Revealing the characteristics of a novel bioflocculant and its flocculation performance in Microcystis aeruginosa removal

    Science.gov (United States)

    Sun, Pengfei; Hui, Cai; Bai, Naling; Yang, Shengmao; Wan, Li; Zhang, Qichun; Zhao, Yuhua

    2015-12-01

    In the present work, a novel bioflocculant, EPS-1, was prepared and used to flocculate the kaolin suspension and Microcystis aeruginosa. We focused on the characteristics and flocculation performance of EPS-1, especially with regard to its protein components. An important attribute of EPS-1 was its protein content, with 18 protein types identified that occupied a total content of 31.70% in the EPS-1. Moreover, the flocculating activity of these protein components was estimated to be no less than 33.93%. Additionally, polysaccharides that occupied 57.12% of the total EPS-1 content consisted of four monosaccharides: maltose, D-xylose, mannose, and D-fructose. In addition, carbonyl, amino, and hydroxyl groups were identified as the main functional groups. Three main elements, namely C1s, N1s, and O1s, were present in EPS-1 with relative atomic percentages of 62.63%, 24.91%, and 10.5%, respectively. Zeta potential analysis indicated that charge neutralization contributed to kaolin flocculation, but was not involved in M. aeruginosa flocculation. The flocculation conditions of EPS-1 were optimized, and the maximum flocculating efficiencies were 93.34% within 2 min for kaolin suspension and 87.98% within 10 min for M. aeruginosa. These results suggest that EPS-1 could be an alternative to chemical flocculants for treating wastewaters and cyanobacterium-polluted freshwater.

  11. The Pseudomonas aeruginosa Type III Translocon Is Required for Biofilm Formation at the Epithelial Barrier

    DEFF Research Database (Denmark)

    Tran, Cindy S; Rangel, Stephanie M; Almblad, Henrik; Kierbel, Arlinet; Givskov, Michael; Tolker-Nielsen, Tim; Hauser, Alan R; Engel, Joanne N

    2014-01-01

    -associated aggregation on the surface of polarized epithelial cells and at early time points in a murine model of acute pneumonia. In contrast, the translocon was not required for aggregation on abiotic surfaces, suggesting a novel function for the type III secretion system during cell-associated aggregation...... about biofilm formation at the epithelial barrier. We have previously shown that when added to the apical surface of polarized epithelial cells, P. aeruginosa rapidly forms cell-associated aggregates within 60 minutes of infection. By confocal microscopy we now show that cell-associated aggregates...... exhibit key characteristics of biofilms, including the presence of extracellular matrix and increased resistance to antibiotics compared to planktonic bacteria. Using isogenic mutants in the type III secretion system, we found that the translocon, but not the effectors themselves, were required for cell...

  12. Characterization of Microcystis Aeruginosa immobilized in complex of PVA and sodium alginate and its application on phosphorous removal in wastewater

    Institute of Scientific and Technical Information of China (English)

    李飞; 毛文娟; 李雪; 王晓钰; 肖智华; 周耀渝; 曾光明

    2015-01-01

    Based on ecological niche theory, Microcystis Aeruginosa (MA) immobilized in the complex of polyvinyl alcohol (PVA) and sodium alginate (SA) crosslinked by CaCl2, was treated as a new kind of special species, and its properties were investigated. Chlorophyll a was used to characterize the bioactivity of the immobilized MA. Results reveal that the gel beads have mechanical strength and chemical stability even under non-sterile harsh conditions, which may be attributed to the rarely seen structure (including three different layers: dense surface, tubular-shaped divergent structure and honeycomb crystal lattice layer) of the immobilized MA determined by scanning electron microscope (SEM). SEM also displays that more quantity of MA is attached to the inwall after cultivation, which demonstrates that the MA within beads maintains high bioactivity. Removal capacities on phosphorous (P) removal in wastewater in the presence and absence of the BG-11 medium were examined, and the removal ratios are 80.3%and 76.7%, respectively, which indicates that the beads without providing ample nutrients still have high capacity of P removal. In addition, control experiment, utilizing polyvinyl alcohol and sodium alginate (PVA-SA) beads without immobilized MA, demonstrates that MA within beads plays the key role in absorbing P.

  13. Removing Remediation Requirements: Effectiveness of Intervention Programs

    Science.gov (United States)

    Fine, Anne; Duggan, Mickle; Braddy, Linda

    2009-01-01

    Remediation of incoming college freshman students is a national concern because remediated students are at higher risk of failing to complete their degrees. Some Oklahoma higher education institutions are working to assist K-12 systems in finding ways to reduce the number of incoming college freshman students requiring remediation. This study…

  14. Pf Filamentous Phage Requires UvrD for Replication in Pseudomonas aeruginosa

    OpenAIRE

    Martínez, Eriel; Campos-Gómez, Javier

    2016-01-01

    ABSTRACT Pf is a lysogenic filamentous phage that promotes biofilm development in Pseudomonas aeruginosa. Pf replicates by a rolling circle replication system which depends on a phage-encoded initiator protein and host factors usually involved in chromosome replication. Rep, an accessory replicative DNA helicase, is crucial for replication of filamentous phages in Escherichia coli. In contrast, here we show that, instead of depending on Rep, Pf replication depends on UvrD, an accessory helica...

  15. Requirements for Pseudomonas aeruginosa Acute Burn and Chronic Surgical Wound Infection

    OpenAIRE

    Turner, Keith H.; Jake Everett; Urvish Trivedi; Rumbaugh, Kendra P.; Marvin Whiteley

    2014-01-01

    Opportunistic infections caused by Pseudomonas aeruginosa can be acute or chronic. While acute infections often spread rapidly and can cause tissue damage and sepsis with high mortality rates, chronic infections can persist for weeks, months, or years in the face of intensive clinical intervention. Remarkably, this diverse infectious capability is not accompanied by extensive variation in genomic content, suggesting that the genetic capacity to be an acute or a chronic pathogen is present in ...

  16. Immobilization of biofilms of Pseudomonas aeruginosa NY3 and their application in the removal of hydrocarbons from highly concentrated oil-containing wastewater on the laboratory scale.

    Science.gov (United States)

    Nie, Maiqian; Nie, Hongyun; He, Meili; Lin, Yingying; Wang, Lei; Jin, Pengkang; Zhang, SenYuan

    2016-05-15

    To explore the potential of Pseudomonas aeruginosa NY3 for the treatment of highly concentrated crude oil-contaminated water, the immobilization of strain NY3 on the surface of polyurethane foam (PUF), the conditions for using these biofilms and the possibility of recovering the used biofilms were studied. The results demonstrated that the biofilm formation process for strain NY3 was quick and easy. Under optimum conditions, the biomass immobilized on the PUF surface could reach 488.32 mg dry cell/g dry PUF. The results demonstrated that when the degradation time was 12 h, the average oil removal rate in 2 g crude oil/L contaminated water was approximately 90% for 40d. Meanwhile, the biofilms could be recovered for reuse. The recovery ability and the high and steady oil removal rate facilitated the application of the biofilms for the removal of concentrated oil from wastewater. PMID:26963906

  17. Influence of rhamnolipids, produced by Pseudomonas aeruginosa NCAIM(P), B001380 on Cr(VI) removal capacity in liquid medium

    OpenAIRE

    Avramović Nataša S.; Nikolić-Mandić Snežana D.; Karadžić Ivanka M.

    2013-01-01

    Pseudomonas aeruginosa NCAIM(P), B001380, a propitious bacterial strain isolated from mineral cutting oil was identified to be chromium tolerant and a producer of biosurfactant rhamnolipid (RL) with potential application in heavy metal bioremediation. Culture growth, RL production and Cr(VI) removal capacity of the strain in the presence of 50 mg L-1 (I) and 100 mg L-1 of Cr(VI) (II) were studied. Maximum of RL production were found in the late-stationary phase at 72 h for both Cr(VI)-a...

  18. Video requirements plan for the HMT equipment removal system

    International Nuclear Information System (INIS)

    This document is the plan defining the video coverage requirements for the equipment removal event of the Hydrogen Mitigation Test (HMT) mixer pump currently installed in high level nuclear waste storage Tank 241-SY-101. When the mixer pump fails the removal and installation of a spare pump will be a time critical event. Since the success of the HMT mixer pump has resolved the DOE safety issue it is absolutely essential that mixing be restored to the tank in a short as time possible. Therefore, the removal of the failed pump and the installation of the spare pump must be anticipated and planned well in advance. The removal, containment, transporting, and storage of the failed pump is a very complex and hazardous task. The successful completion of this task will require careful planning and monitoring. Certain events, during the removal and subsequent installation of the new pump, will require video observation and storage for safety, documenting, training, and promotional use. Furthermore, certain events will require close monitoring and observation by the event directors and key supervisory personnel for the execution of specific tasks during the equipment removal event

  19. Use of RSM modeling for optimizing decolorization of simulated textile wastewater by Pseudomonas aeruginosa strain ZM130 capable of simultaneous removal of reactive dyes and hexavalent chromium.

    Science.gov (United States)

    Maqbool, Zahid; Hussain, Sabir; Ahmad, Tanvir; Nadeem, Habibullah; Imran, Muhammad; Khalid, Azeem; Abid, Muhammad; Martin-Laurent, Fabrice

    2016-06-01

    Remediation of colored wastewater loaded with dyes and metal ions is a matter of interest nowadays. In this study, 220 bacteria isolated from textile wastewater were tested for their potential to decolorize each of the four reactive dyes (reactive red-120, reactive black-5, reactive yellow-2, and reactive orange-16) in the presence of a mixture of four different heavy metals (Cr, Zn, Pb, Cd) commonly found in textile effluents. Among the tested bacteria, the isolate ZM130 was found to be the most efficient in decolorizing reactive dyes in the presence of the mixture of heavy metals and was identified as Pseudomonas aeruginosa strain ZM130 by 16S rRNA gene analysis. The strain ZM130 was highly effective in simultaneously removing hexavalent chromium (25 mg L(-1)) and the azo dyes (100 mg L(-1)) from the simulated wastewater even in the presence of other three heavy metals (Zn, Pb, Cd). Simultaneous removal of chromium and azo dyes ranged as 76.6-98.7 % and 51.9-91.1 %, respectively, after 180 h incubation. On the basis of quadratic polynomial equation and response surfaces given by the response surface methodology (RSM), optimal salt content, pH, carbon co-substrate content, and level of multi-metal mixtures for decolorization of reactive red-120 in a simulated textile wastewater by the strain ZM130 were predicted to be 19.8, 7.8, and 6.33 g L(-1) and a multi-metal mixture (Cr 13.10 mg L(-1), Pb 26.21 mg L(-1), Cd 13.10 mg L(-1), Zn 26.21 mg L(-1)), respectively. Moreover, the strain ZM130 also exhibited laccase and nicotinamide adenine dinucleotide (reduced)-dichlorophenolindophenol reductase (NADH-DCIP reductase) activity during the decolorization of reactive red-120. However, the laccase activity was found to be maximum in the presence of 300 mg L(-1) of the dye as compared to other concentrations. Hence, the isolation of this strain might serve as a potential bio-resource required for developing the strategies aiming at bioremediation of the

  20. Pf Filamentous Phage Requires UvrD for Replication in Pseudomonas aeruginosa.

    Science.gov (United States)

    Martínez, Eriel; Campos-Gómez, Javier

    2016-01-01

    Pf is a lysogenic filamentous phage that promotes biofilm development in Pseudomonas aeruginosa. Pf replicates by a rolling circle replication system which depends on a phage-encoded initiator protein and host factors usually involved in chromosome replication. Rep, an accessory replicative DNA helicase, is crucial for replication of filamentous phages in Escherichia coli. In contrast, here we show that, instead of depending on Rep, Pf replication depends on UvrD, an accessory helicase implicated in DNA repair. In this study, we also identified the initiator protein of Pf and found that it shares similarities with that of Vibrio phages CTXφ and VGJφ, which also depend on UvrD for replication. A structural comparative analysis of the initiator proteins of most known filamentous phages described thus far suggested that UvrD, known as a nonreplicative helicase, is involved in rolling circle replication of filamentous phages in diverse bacteria genera. This report consolidates knowledge on the new role of UvrD in filamentous phage replication, a function previously thought to be exclusive of Rep helicase. IMPORTANCE Biofilm development is a key component of the ability of Pseudomonas aeruginosa to evade host immune defenses and resist multiple drugs. Induction of the filamentous phage Pf, which usually is lysogenized in clinical and environmental isolates of P. aeruginosa, plays an important role in biofilm assembly, maturation, and dispersal. Despite the clinical relevance of Pf, the molecular biology of this phage is largely unknown. In this study, we found that rolling circle replication of Pf depends on UvrD, a DNA helicase normally involved in DNA repair. We also identified the initiator protein of Pf and found that it shares structural similarity with that of Vibrio cholerae phages CTXφ and VGJφ, which also use UvrD for replication. Our results reveal that, in addition to DNA repair, UvrD plays an essential role in rolling circle replication of filamentous

  1. Anaerobic survival of Pseudomonas aeruginosa by pyruvate fermentation requires an Usp-type stress protein

    DEFF Research Database (Denmark)

    Schreiber, K; Boes, N; Escbach, M;

    2006-01-01

    activity was detected in the deeper layers of a P. aeruginosa biofilm using a PPA3309-gfp (green fluorescent protein gene) fusion and confocal laser-scanning microscopy. This is the first description of an Anr-dependent, anaerobically induced, and functional Usp-like protein in bacteria....... the induced synthesis of three enzymes involved in arginine fermentation, ArcA, ArcB, and ArcC, and the outer membrane protein OprL. Moreover, formation of two proteins of unknown function, PA3309 and PA4352, increased by factors of 72- and 22-fold, respectively. Both belong to the group of universal stress...... proteins (Usp). Long-term survival of a PA3309 knockout mutant by pyruvate fermentation was found drastically reduced. The oxygen-sensing regulator Anr controls expression of the PPA3309-lacZ reporter gene fusion after a shift to anaerobic conditions and further pyruvate fermentation. PA3309 expression...

  2. Required ozone doses for removing pharmaceuticals from wastewater effluents

    DEFF Research Database (Denmark)

    Antoniou, Maria; Hey, Gerly; Rodríguez Vega, Sergio;

    2013-01-01

    The aim of the this study was to investigate the ozone dosage required to remove active pharmaceutical ingredients (APIs) from biologically treated wastewater of varying quality, originated from different raw wastewater and wastewater treatment processes.Secondary effluents from six Swedish...

  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. Influence of rhamnolipids, produced by Pseudomonas aeruginosa NCAIM(P, B001380 on Cr(VI removal capacity in liquid medium

    Directory of Open Access Journals (Sweden)

    Avramović Nataša S.

    2013-01-01

    Full Text Available Pseudomonas aeruginosa NCAIM(P, B001380, a propitious bacterial strain isolated from mineral cutting oil was identified to be chromium tolerant and a producer of biosurfactant rhamnolipid (RL with potential application in heavy metal bioremediation. Culture growth, RL production and Cr(VI removal capacity of the strain in the presence of 50 mg L-1 (I and 100 mg L-1 of Cr(VI (II were studied. Maximum of RL production were found in the late-stationary phase at 72 h for both Cr(VI-amended cultures: I (236 mg L-1 and II (160 mg L-1, as well as the maximum of Cr(VI removal capacity: 70 % (I and 57 % (II. The amount of Cr in RL preparation II was 22 mg mg-1 determined by flame atomic absorption spectroscopy (FAAS. Appearance of a new band at 914 cm-1 in infrared (IR spectrum of RL (II indicated a significant proof for possible coordination of CrO42-ion with RL. The effect of Cr(VI on monorhamnolipids (RL1 and dirhamnolipids (RL2 distribution and its ratio were studied by electrospray ionization mass spectrometry (ESI-MS. An increase was observed in a RL2/RL1 ratio for II compared to control.

  5. Conditions for effective removal of pyrene from an artificially contaminated soil using Pseudomonas aeruginosa 57SJ rhamnolipids

    International Nuclear Information System (INIS)

    The efficacy of a new rhamnolipid biosurfactants mixture to enhance the removal of pyrene from a soil artificially contaminated was investigated. The molar solubilization ratio (MSR) and the partition coefficient between the micelles and water (log K m) were found to be 7.5 x 10-3 and 5.7, respectively. From soil column studies, the pyrene removal increased linearly with the concentration of the injected biosurfactants solution above the effective critical micellar concentration (0.4 g L-1). Flushing with a 5.0 g L-1 biosurfactants solution increased the pyrene concentration in the effluent by 178 times. At high biosurfactants' concentrations (2.5 and 5.0 g L-1), the cumulative pyrene recovery reached 70%. This pyrene remobilization takes place independently of the soil organic carbon solubilization. This study provides a combination of batch and column experiments in order to find the conditions for effective soil remediation using a new rhamnolipids mixture. - The potential of newly isolated biosurfactants to mobilize PAHs from contaminated soils was evaluated from the determination in dynamic conditions of their effective critical micellar concentration

  6. Conditions for effective removal of pyrene from an artificially contaminated soil using Pseudomonas aeruginosa 57SJ rhamnolipids

    Energy Technology Data Exchange (ETDEWEB)

    Bordas, Francois [Institut national de la recherche scientifique, Centre INRS-Eau-Terre-Environnement, Universite du Quebec, 2800 rue Einstein, C.P. 7500, Sainte-Foy, Quebec, G1V 4C7 (Canada)]. E-mail: francois.bordas@unilim.fr; Lafrance, Pierre [Institut national de la recherche scientifique, Centre Eau, Terre et Environnement, Universite du Quebec, 490, rue de la Couronne, Quebec, G1K 9A9 (Canada)]. E-mail: pierre_lafrance@inrs-ete.uquebec.ca; Villemur, Richard [Institut national de la recherche scientifique, Centre INRS-Institut Armand Frappier, Universite du Quebec, 531 bd des Prairies, Laval, Quebec, H7V 1B7 (Canada)]. E-mail: richard.villemur@inrs-iaf.uquebec.ca

    2005-11-15

    The efficacy of a new rhamnolipid biosurfactants mixture to enhance the removal of pyrene from a soil artificially contaminated was investigated. The molar solubilization ratio (MSR) and the partition coefficient between the micelles and water (log K {sub m}) were found to be 7.5 x 10{sup -3} and 5.7, respectively. From soil column studies, the pyrene removal increased linearly with the concentration of the injected biosurfactants solution above the effective critical micellar concentration (0.4 g L{sup -1}). Flushing with a 5.0 g L{sup -1} biosurfactants solution increased the pyrene concentration in the effluent by 178 times. At high biosurfactants' concentrations (2.5 and 5.0 g L{sup -1}), the cumulative pyrene recovery reached 70%. This pyrene remobilization takes place independently of the soil organic carbon solubilization. This study provides a combination of batch and column experiments in order to find the conditions for effective soil remediation using a new rhamnolipids mixture. - The potential of newly isolated biosurfactants to mobilize PAHs from contaminated soils was evaluated from the determination in dynamic conditions of their effective critical micellar concentration.

  7. Disulfide Bond in Pseudomonas aeruginosa Lipase Stabilizes the Structure but Is Not Required for Interaction with Its Foldase

    OpenAIRE

    Liebeton, Klaus; Zacharias, Annette; Jaeger, Karl-Erich

    2001-01-01

    Pseudomonas aeruginosa secretes a 29-kDa lipase which is dependent for folding on the presence of the lipase-specific foldase Lif. The lipase contains two cysteine residues which form an intramolecular disulfide bond. Variant lipases with either one or both cysteines replaced by serines showed severely reduced levels of extracellular lipase activity, indicating the importance of the disulfide bond for secretion of lipase through the outer membrane. Wild-type and variant lipase genes fused to ...

  8. The galactophilic lectin (PA-IL, gene LecA) from Pseudomonas aeruginosa. Its binding requirements and the localization of lectin receptors in various mouse tissues

    DEFF Research Database (Denmark)

    Kirkeby, Svend; Hansen, Axel K; d'Apice, Anthony;

    2006-01-01

    The opportunistic pathogen Pseudomonas aeruginosa contains lectins of which one of them, PA-IL (gene lecA), shows preference for alpha-galactosylated glycans. The bacterial lectin is probably important in the carbohydrate-mediated adhesion of the microorganism to endothelia and epithelia and...... thereby the lectin facilitates entering and damaging of the cells. The requirements for the interaction between PA-IL and the carbohydrate epitopes to which the bacterial lectin may bind were here Studied using alpha-galactosylated neoglycoproteins that were immobilized on Microtiter plates. It is...... concluded that the carbohydrate recognizing site of the lectin can have a binding requirement of only one saccharide. Lectin histochemistry was performed on sections from wild type mice and from knock-out mice, which lack function of the alpha.1,3-galactosyltransferase gene. All assays with the P...

  9. Optimized Reaction Conditions for Removal of Cellular Organic Matter of Microcystis aeruginosa During the Destabilization and Aggregation Process Using Ferric Sulfate in Water Purification

    Czech Academy of Sciences Publication Activity Database

    Pivokonský, Martin; Polášek, Pavel; Pivokonská, Lenka; Tomášková, Hana

    2009-01-01

    Roč. 81, č. 5 (2009), s. 514-522. ISSN 1061-4303 R&D Projects: GA ČR GA103/07/0295 Institutional research plan: CEZ:AV0Z20600510 Keywords : Microcystis aeruginosa * cellular organic matter * destabilization * aggregation * optimized reaction conditions * water purification Subject RIV: BK - Fluid Dynamics Impact factor: 0.965, year: 2009

  10. 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

  11. Technical Requirements for Fabrication and Installation of Removable Shield for CNRF in HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Jeong Soo; Cho, Yeong Garp; Lee, Jung Hee; Shin, Jin Won

    2008-04-15

    This report details the technical requirements for the fabrication and installation of the removable shield for the Cold Neutron Research Facility (CNRF) in HANARO reactor hall. The removable shield is classified as non-nuclear safety (NNS), seismic category II, and quality class T. The main function of the removable shield is to do the biological shielding of neutrons and gamma from the CN port and the guides. The removable shield consists of block type walls and roofs that can be necessarily assembled, disassembled and moveable. These will be installed between the reactor pool wall and the CNS guide bunker in. This report describes technical requirements for the removable shield such as quality assurance, seismic analysis requirements, configuration, concrete compositions, fabrication and installation requirements, test and inspection, shipping, delivery, etc. Appendix is the technical specification of structural design and analysis. Attachments are composed of the technical specification for the fabrication of the removable shield, shielding design drawings and procurement quality requirements. These technical requirements will be provided to a contract for the manufacturing and installation.

  12. 75 FR 56912 - Live Goats and Swine for Export; Removal of Certain Testing Requirements

    Science.gov (United States)

    2010-09-17

    ... Animal and Plant Health Inspection Service 9 CFR Part 91 RIN 0579-AD18 Live Goats and Swine for Export; Removal of Certain Testing Requirements AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION... requirement for pre-export tuberculosis and brucellosis testing of goats and breeding swine intended...

  13. 76 FR 66875 - Informal Entry Limit and Removal of a Formal Entry Requirement

    Science.gov (United States)

    2011-10-28

    ... increasing the informal entry limit to $2,500 will save the trade community approximately $11 million in... informal entry from $2,000 to $2,500. Unless exempt under a free trade agreement and in addition to any..., 143, 145, and 148 RIN 1515-AD69 Informal Entry Limit and Removal of a Formal Entry Requirement...

  14. PlcR1 and PlcR2 are putative calcium-binding proteins required for secretion of the hemolytic phospholipase C of Pseudomonas aeruginosa.

    OpenAIRE

    Cota-Gomez, A; Vasil, A I; Kadurugamuwa, J; Beveridge, T J; Schweizer, H. P.; Vasil, M L

    1997-01-01

    The plcHR operon of Pseudomonas aeruginosa includes the structural gene for the hemolytic phospholipase C,plcH (previously known as plcS), and two overlapping, in-phase, genes designated plcR1 and plcR2. Hemolytic and phospholipase C (PLC) activities produced by Escherichia coli and P. aeruginosa T7 expression systems were measured in strains carrying both plcH and plcR genes and in strains carrying each gene separately. When plcH was expressed by itself in the E. coli T7 system, the area of ...

  15. The MexJK Efflux Pump of Pseudomonas aeruginosa Requires OprM for Antibiotic Efflux but Not for Efflux of Triclosan

    OpenAIRE

    Chuanchuen, Rungtip; Narasaki, Craig T.; Schweizer, Herbert P.

    2002-01-01

    Using the biocide triclosan as a selective agent, several triclosan-resistant mutants of a susceptible Pseudomonas aeruginosa strain were isolated. Cloning and characterization of a DNA fragment conferring triclosan resistance from one of these mutants revealed a hitherto uncharacterized efflux system of the resistance nodulation cell division (RND) family, which was named MexJK and which is encoded by the mexJK operon. Expression of this operon is negatively regulated by the product of mexL,...

  16. 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...

  17. Combination process of limited filamentous bulking and nitrogen removal via nitrite for enhancing nitrogen removal and reducing aeration requirements.

    Science.gov (United States)

    Guo, Jianhua; Peng, Yongzhen; Yang, Xiong; Gao, Chundi; Wang, Shuying

    2013-03-01

    Limited filamentous bulking (LFB) activated sludge process was proposed by Guo et al. (2010) to increase the removal of tiny suspended particulates in the clarifier and reduce aeration energy consumption. However, when the use of LFB process, ammonium removal efficiency would be compromised due to low dissolved oxygen (DO). In this study, the combination process of nitrogen removal via nitrite and LFB was achieved to enhance nitrogen removal and reduce aeration energy consumption by controlling low DO levels (0.5-1.0 mg L(-1)) in a lab-scale anoxic-oxic reactor (V=66 L) treating real domestic wastewater at room temperature. Above 85% of nitrite accumulation ratio was steadily maintained during continuous operation period. The combined process improved the total nitrogen (TN) removal by about 20% in comparison to the traditional process via the nitrate pathway, and also reduced the specific aeration energy consumption by 35%. COD, ammonium and TN removal efficiencies were up to 86%, 94% and 75%, respectively. The process proved effective in achieving a steady LFB state, whereby sludge volume index between 150 and 250 mL g(-1) was sustained for long-term operation. The microbial community structure was analyzed by fluorescence in situ hybridization, which indicated ammonia-oxidizing bacteria out-competed nitrite-oxidizing bacteria. Moreover, the filaments Type 0041 and Microthrix parvicella proliferated with limited abundance. The results indicated the combination process of LFB and nitrogen removal via nitrite under low DO was a feasible solution for saving energy and enhancing nitrogen removal when treating domestic wastewater. PMID:23305749

  18. Comparison of the time required for removal of intraradicular cast posts using two Brazilian ultrasound devices

    Directory of Open Access Journals (Sweden)

    Manoel Brito-Júnior

    2009-03-01

    Full Text Available The aim of this in vitro study was to compare the time required for removal of intraradicular cast posts cemented with zinc phosphate (ZF or glass ionomer cement (GIC, using two Brazilian ultrasound devices (BUD. Seventy two human inferior premolars with single root canals were sectioned transversally at the cementoenamel junction. In each specimen, the root canal was endodontically treated, the post space was prepared to a depth of 9 mm and the canal was molded to obtain a post impression. After the casting procedures, the posts were randomly distributed into 2 groups (n = 36 according to the luting material used: G1 - ZF and G2 - GIC. The tooth and luted post set was then embedded in an acrylic resin block. The groups were then divided into 3 subgroups (n = 12 according to the ultrasound device used: A - Enac (Osada Electric, Japan, used as a control group; B - Profi II Ceramic (Dabi Atlante, Brazil and C - Jet Sonic Satelec (Gnatus, Brazil. The posts were submitted to the vibration process with maximum power set on all surrounding surfaces. Time of application was recorded with a chronometer until complete post dislodgment, and the data were analyzed by the ANOVA test (p < 0.05. The averages required for post removal in G1 and G2 were respectively 41.42 and 92.03 seconds, with significant statistical difference (p = 0.001. No statistical difference was observed among the three ultrasound devices (p = 0.088, and the BUD presented a performance similar to that of the international gold standard device (Enac. Moreover, the type of luting agent had a greater influence on the time required for post removal than the origin of the ultrasonic unit.

  19. Removal of damaged proteins during ES cell fate specification requires the proteasome activator PA28

    DEFF Research Database (Denmark)

    Hernebring, Malin; Fredriksson, Asa; Liljevald, Maria; Cvijovic, Marija; Norrman, Karin; Wiseman, John; Semb, Tor Henrik; Nyström, Thomas

    2013-01-01

    In embryonic stem cells, removal of oxidatively damaged proteins is triggered upon the first signs of cell fate specification but the underlying mechanism is not known. Here, we report that this phase of differentiation encompasses an unexpected induction of genes encoding the proteasome activato...... that PA28aß has a hitherto unidentified role required for resetting the levels of protein damage at the transition from self-renewal to cell differentiation.......In embryonic stem cells, removal of oxidatively damaged proteins is triggered upon the first signs of cell fate specification but the underlying mechanism is not known. Here, we report that this phase of differentiation encompasses an unexpected induction of genes encoding the proteasome activator...... PA28aß (11S), subunits of the immunoproteasome (20Si), and the 20Si regulator TNFa. This induction is accompanied by assembly of mature PA28-20S(i) proteasomes and elevated proteasome activity. Inhibiting accumulation of PA28a using miRNA counteracted the removal of damaged proteins demonstrating...

  20. 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...

  1. Microbial cells as biosorbents for heavy metals: accumulation of Uranium by Saccharomyces cerevisiae and Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Uranium accumulated extracellularly on the surfaces of Saccharomyces cerevisiae cells. The rate and extent of accumulation were subject to environmental parameters, such as pH, temperature, and interference by certain anions and cations. Uranium accumulation by Pseudomonas aeruginosa occurred intracellularly and was extremely rapid (<10 s), and no response to environmental parameters could be detected. Metabolism was not required for metal uptake by either organism. Cell-bound uranium reached a concentration of 10 to 15% of the dry cell weight, but only 32% of the S. cerevisiae cells and 44% of the P. aeruginosa cells within a given population possessed visible uranium deposits when examined by electron microscopy. Rates of uranium uptake by S. cerevisiae were increased by chemical pretreatment of the cells. Uranium could be removed chemically from S. cerevisiae cells, and the cells could then be reused as a biosorbent

  2. 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 ...

  3. 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...

  4. A law of removing radon by ventilation and air requirement calculation for eliminating radon daughters in uranium mines

    International Nuclear Information System (INIS)

    In accordance with testing data of removing radon and its daughters by ventilation from shrinkage and filling stopes of uranium mines, a law of removing radon by ventilation from the stopes is analyzed and summed. According to the decay law of radon and its daughters, an accumulation equation of potential alpha energy from radon daughters is presented with hyperbolic regression equation. the calculating formulae of ventilation flow are derived from the accumulation equation for eliminating radon daughters in inlet flow with or without contamination. It has been proved that the amount of ventilation air calcuated could meet the requirements of radiation safety rationally and economically

  5. 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...

  6. Preliminary Test Requirements for the Performance Test of Passive Decay Heat Removal System of Sodium-Cooled Fast Reactor

    International Nuclear Information System (INIS)

    In order to verify the concept of safety grade passive decay removal system PDRC (Passive Decay heat Removal Circuit) of KALIMER-600 and the design features to resolve the design issues for securing the cooling performance, the performance test is implemented. In this report, the preliminary test requirements for using as a guideline to the design of the experimental facility were established. Since the experimental facility should be designed so as to simulate the various thermal- hydraulic phenomena, as closely as possible, to be occurred in reference reactor during the decay heat removal operation, the design characteristics of the reference reactor (KALIMER-600) were analyzed for drawing major constitutive elements to be simulated in the facility. The preliminary test matrix was set up by the analysis of various design basis events and then the key test matrix was determined. Also, the priority for various thermal hydraulic phenomena which should be considered in the design of the experimental facility was determined by analyzing the phenomena for each key test matrix. Based on the analysis, the general design requirements for experimental facility were prepared and the design requirements for fluid systems and instrumentation were established. The test requirements in this report will be reflected in the scaling analysis and the basic design of the experimental facility. The test matrix specified in this report can be modified in the stage of main testing by considering the needs of experiments and circumstances at that time

  7. Enhanced Biological Phosphorus Removal from Dairy Manure to Meet Nitrogen:Phosphorus Crop Nutrient Requirements

    OpenAIRE

    Yanosek, Kristina Anne

    2002-01-01

    Over the last two decades, livestock operations have become highly concentrated due to growing trends towards larger, more confined facilities and a decrease in cropland on smaller farms. This has led to greater amounts of excess manure nutrients on farms, increasing the potential for nutrient pollution of water bodies from runoff. The purpose of this study was to determine if enhanced biological phosphorus removal (EBPR) is a viable alternative for managing excess manure nutrients on dairy...

  8. Influence of luting agents on time required for cast post removal by ultrasound: an in vitro study

    Directory of Open Access Journals (Sweden)

    Janir Alves Soares

    2009-06-01

    Full Text Available OBJECTIVE: This in vitro study evaluated the influence of luting agents on ultrasonic vibration time for intraradicular cast post removal. MATERIAL AND METHODS: After endodontic treatment, 30 roots of extracted human canines were embedded in resin cylinders. The post-holes were prepared at 10 mm depth and their impressions were taken using autopolymerizing acrylic resin. After casting procedures using a nickel-chromium alloy, the posts were randomly distributed into 3 groups (n=10 according to the luting material: G1- zinc phosphate (SS White (control group, G2 - glass ionomer cement (Vidrion C; SS White, and G3- resin cement (C&B; Bisco. In G3, the adhesive procedure was performed before post cementation. After 24 h, the cement line was removed at the post/tooth interface using a fine diamond bur, and the ST-09 tip of an Enac ultrasound unit was applied at maximum power on all surfaces surrounding the posts. The application time was recorded with a chronometer until the post was completely dislodged and data were analyzed by ANOVA and Tukey's test (p<0.05. RESULTS: The roots were removed from the acrylic resin and inspected to detect cracks and/or fractures. The means for G1, G2, and G3 were 168.5, 59.5, and 285 s, respectively, with statistically significant differences among them. Two G3 posts resisted removal, one of which developed a vertical fracture line. CONCLUSIONS: Therefore, the cement type had a direct influence on the time required for ultrasonic post removal. Compared to the zinc phosphate and glass ionomer cements, the resin cement required a longer ultrasonic vibration time.

  9. 76 FR 41434 - Removal of Certain Requirements Related to the Prescription Drug Marketing Act; Opportunity for...

    Science.gov (United States)

    2011-07-14

    ... proposed rule to require that the pedigree only go back to the last authorized distributor of record (64 FR... with the manufacturer, and that the identifying statement (also known as the ``pedigree'') must include... respect to the statutory pedigree requirements of the PDMA, as long as the pedigree identifies the...

  10. Autotrophic nitrogen removal from black water: calcium addition as a requirement for settleability.

    Science.gov (United States)

    de Graaff, M S; Temmink, H; Zeeman, G; van Loosdrecht, M C M; Buisman, C J N

    2011-01-01

    Black (toilet) water contains half of the organic load in the domestic wastewater, as well as the major fraction of the nutrients nitrogen and phosphorus. When collected with vacuum toilets, the black water is 25 times more concentrated than the total domestic wastewater stream, i.e. including grey water produced by laundry, showers etc. A two-stage nitritation-anammox process was successfully employed and removed 85%-89% of total nitrogen in anaerobically treated black water. The (free) calcium concentration in black water was too low (42 mg/L) to obtain sufficient granulation of anammox biomass. The granulation and retention of the biomass was improved considerably by the addition of 39 mg/L of extra calcium. This resulted in a volumetric nitrogen removal rate of 0.5 gN/L/d, irrespective of the two temperatures of 35 °C and 25 °C at which the anammox reactors were operated. Nitrous oxide, a very strong global warming gas, was produced in situations of an incomplete anammox conversion accompanied by elevated levels of nitrite. PMID:20822793

  11. The kilE locus of promiscuous IncP alpha plasmid RK2 is required for stable maintenance in Pseudomonas aeruginosa.

    OpenAIRE

    Wilson, J. W.; Sia, E A; Figurski, D H

    1997-01-01

    Eight coordinately regulated operons constitute the kor regulon of the IncP alpha plasmid RK2. Three operons specify functions required for replication initiation, conjugative transfer, and control of gene expression. The functions of the other operons, including those of the four coregulated operons that compose the kilA, kilC, and kilE loci, have not been determined. Here, we present the first evidence that a kil determinant is involved in IncP plasmid maintenance. Elevation of KorC levels ...

  12. Reducing prospective memory error and costs in simulated air traffic control: External aids, extending practice, and removing perceived memory requirements.

    Science.gov (United States)

    Loft, Shayne; Chapman, Melissa; Smith, Rebekah E

    2016-09-01

    In air traffic control (ATC), forgetting to perform deferred actions-prospective memory (PM) errors-can have severe consequences. PM demands can also interfere with ongoing tasks (costs). We examined the extent to which PM errors and costs were reduced in simulated ATC by providing extended practice, or by providing external aids combined with extended practice, or by providing external aids combined with instructions that removed perceived memory requirements. Participants accepted/handed-off aircraft and detected conflicts. For the PM task, participants were required to substitute alternative actions for routine actions when accepting aircraft. In Experiment 1, when no aids were provided, PM errors and costs were not reduced by practice. When aids were provided, costs observed early in practice were eliminated with practice, but residual PM errors remained. Experiment 2 provided more limited practice with aids, but instructions that did not frame the PM task as a "memory" task led to high PM accuracy without costs. Attention-allocation policies that participants set based on expected PM demands were modified as individuals were increasingly exposed to reliable aids, or were given instructions that removed perceived memory requirements. These findings have implications for the design of aids for individuals who monitor multi-item dynamic displays. (PsycINFO Database Record PMID:27608067

  13. 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...

  14. 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 ...

  15. Estimating Pollutant Removal Requirements for Landfills in the UK: II. Model Development

    OpenAIRE

    Hall, D H; Drury, D.; Gronow, Jan R.; Rosevear, Alan; Pollard, Simon J. T.; Smith, Richard

    2006-01-01

    A modelling methodology using a leachate source term has been produced for estimating the timescales for achieving environmental equilibrium status for landfilled waste. Results are reported as the period of active management required for modelled scenarios of non-flushed and flushed sites for a range of pre-filling treatments. The base scenario against which results were evaluated was raw municipal solid waste (MSW) for which only cadmium failed to reach equilibrium. Flushe...

  16. Requirements for a helium-cooled blanket heat removal system development facility for fusion reactor research

    International Nuclear Information System (INIS)

    Existing and potential design problems associated with the helium-cooled blanket assemblies of experimental, demonstration and hybrid reactor designs considered in the Magnetic Fusion Energy (MFE) Program were assessed. It was observed that a balanced program of design, analysis and experimentation would be required to develop, verify and qualify these designs and those of related hardware and equipment. To respond to the potential experimental requirements of the first-generation reactors (the EPRs and possibly the hybrid concept), the need for a helium test facility was identified. It was determined that this facility should have the capacity for recirculating 100,000 kg/hr of helium at 70 atm and 6000C and should have 3 MW of electrical power available for simulating neutron heating. No radioactive material or processes should be used to facilitate ''hands-on'' experimentation and development. The general types of testing anticipated in this facility would include: (1) thermal and coolant flow performance of the blanket and other components in the primary cooling circuit; (2) structural adequacy of the blanket and first wall including vibration considerations; (3) capability for accommodating safety/off-normal conditions. Existing facilities worldwide were surveyed. It was determined that a number of facilities exist in foreign nations for performing the anticipated experiments. However, no large helium gas flow loop exists within the USA. Consequently, it is recommended that a helium thermal-hydraulic blanket test facility be planned and build on a schedule that will meet the unique design development and verification needs of the fusion program. This report provides the rationale and preliminary scoping of the operational characteristics and requirements for such a facility

  17. 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...

  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. Antibacterial, anti-swarming and anti-biofilm formation activities of Chamaemelum nobile against Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Hossein Kazemian

    2015-08-01

    Full Text Available AbstractINTRODUCTION:Chamomile ( Chamaemelum nobile is widely used throughout the world, and has anti-inflammatory, deodorant, bacteriostatic, antimicrobial, carminative, sedative, antiseptic, anti-catarrhal, and spasmolytic properties. Because of the increasing incidence of drug-resistant bacteria, the development of natural antibacterial sources such as medical herbs for the treatment of infectious diseases is necessary. Extracts from different plant parts such as the leaves, flowers, fruit, and bark of Combretum albiflorum, Laurus nobilis , and Sonchus oleraceus were found to possess anti-quorum sensing (QS activities. In this study, we evaluated the effect of C. nobile against Pseudomonas aeruginosa biofilm formationMETHODS:The P. aeruginosa samples were isolated from patients with different types of infection, including wound infection, septicemia, and urinary tract infection. The flowers of C. nobile were dried and the extract was removed using a rotary device and then dissolved in dimethyl sulfoxide at pH 7.4. The microdilution method was used to evaluate the minimum inhibitory concentration (MIC of this extract on P. aeruginosa , and biofilm inhibition was assayed.RESULTS:Eighty percent of the isolated samples (16/20 could form a biofilm, and most of these were isolated from wound infections. The biofilm inhibitory concentration of the C. nobile extract was 6.25-25mg/ml, whereas the MIC was 12.5-50mg/ml.CONCLUSIONS:The anti-QS property of C. nobile may play an important role in its antibacterial activity, thus offering an additional strategy in the fight against bacterial infections. However, molecular investigation is required to explore the exact mechanisms of the antibacterial action and functions of this phytocompound.

  20. 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....

  1. 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

  2. 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)

  3. In vitro efficacy of octenidine and polihexanide against biofilms composed of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Siebert, Jörg

    2007-12-01

    Full Text Available The removal and inactivation of biofilms through wound cleansing solutions with and without antimicrobial supplements (octenidine dihydrochloride, polihexanide have been investigated in a laboratory model with Pseudomonas aeruginosa. Plastic slides of polycarbonate grown over with P. aeruginosa for 1 week were incubated with the cleansing solutions for 60 min. Removal and inactivation of the biofilm were determined by staining with crystal violet and by plating, respectively. No inhibition occurred by supplementing the cleansing solutions with octenidine or polyhexanide. By using octenidine and polihexanide a pronounced decrease in colony numbers of the biofilm was achieved compared to pure salt solutions (NaCl, Ringer.

  4. 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

  5. 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.

  6. 33 CFR 149.103 - What are the requirements for discharge containment and removal material and equipment?

    Science.gov (United States)

    2010-07-01

    ... discharge containment and removal material and equipment? 149.103 Section 149.103 Navigation and Navigable... containment and removal material and equipment? (a) Each deepwater port must have a facility response plan... cognizant Captain of the Port. (b) The facility response plan must identify adequate spill containment...

  7. 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...

  8. 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...

  9. Pseudomonas aeruginosa biofilm formation and slime excretion on antibiotic-loaded bone cement

    NARCIS (Netherlands)

    Neut, D; Hendriks, JGE; van Horn, [No Value; van der Mei, HC; Busscher, HJ

    2005-01-01

    Background Infection is an infrequent but serious complication of prosthetic joint surgery. These infections will usually not clear until the implant is removed and re-implantation has a high failure rate, especially when Pseudomonas aeruginosa is involved. Material and methods We examined Pseudomon

  10. 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 ...

  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. Fate and effects of octylphenol in a Microcystis aeruginosa culture medium

    International Nuclear Information System (INIS)

    Octylphenol (OP) is a xenobiotic with endocrine disrupting properties found in freshwaters worldwide. Its effects have been studied in organisms with nuclear receptors but effects on phytoplankton communities are poorly characterized, despite the fact that these organisms are constantly exposed to this compound. For this reason fate and effects of OP in the cyanobacterium Microcystis aeruginosa were assessed from 10 nM to 5 μM OP concentration. Up to a test concentration of 250 nM, OP removal increased significantly in the presence of cyanobacteria, the compound half-life in the absence of cells being 15 days against 9 days in the presence of the cells. Only 4% of the total OP removed was found bound to the cells, indicating an active metabolization of the compound. Moreover, the role of the exudates produced by M. aeruginosa, in the OP removal from culture medium, was assessed. Culture medium with exudates, resulting from a 7-day growth of M. aeruginosa, spiked with 50 nM OP, showed a higher half-life (22 days). Compared to culture medium without exudates, it can be hypothesized that higher organic matter concentrations make the hydrolysis or photolysis of OP more difficult. In culture media, the cells of M. aeruginosa could compensate and even counteract this, as OP half-life was shortened. At higher OP levels (1.25 and 5 μM) M. aeruginosa growth was impaired, indicating toxic effects. This shortage of biomass prevented the M. aeruginosa-assisted OP withdrawal from the culture media

  13. 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.

  14. 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.

  15. Sewage sludge ash to phosphate fertilizer by chlorination and thermal treatment: residence time requirements for heavy metal removal.

    Science.gov (United States)

    Nowak, Benedikt; Wegerer, Harald; Aschenbrenner, Philipp; Rechberger, Helmut; Winter, Franz

    2012-01-01

    Heavy metal removal from sewage sludge ash can be performed by mixing the ash with environmentally compatible chlorides (e.g. CaCl2 or MgCl2) and water, pelletizing the mixture and treating the pellets in a rotary reactor at about 1000 degrees C. Thermogravimetry-mass spectroscopy, muffle oven tests (500-1150 degrees C) and investigations in a laboratory-scale rotary reactor (950-1050 degrees C, residence time 1-25 min) were carried out. In the rotary reactor, up to 97% of Cu, 95% Pb and 95% Zn can be removed at 1050 degrees C. As Cl release starts from 400 degrees C (obtained from thermogravimetry-mass spectrometry experiments), heavy metals are already removed partially within the heating period. This heavy metal removal can be described as being similar to a first-order rate law. To meet the limit values specified in the Austrian and German fertilizer ordinances, residence times of the order of minutes are sufficient at 950 degrees C. PMID:23393980

  16. 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...

  17. INFLUENCE OF LUTING AGENTS ON TIME REQUIRED FOR CAST POST REMOVAL BY ULTRASOUND: AN IN VITRO STUDY

    OpenAIRE

    Janir Alves Soares; Manoel Brito-Júnior; Dimitri Ribas Fonseca; Anielo Faleiro Melo; Suelleng Maria Cunha Santos; Nadia Del Carmen Soto Sotomayor; Neilor Mateus Antunes Braga; Silva, André Luis Faria e

    2009-01-01

    OBJECTIVE: This in vitro study evaluated the influence of luting agents on ultrasonic vibration time for intraradicular cast post removal. MATERIAL AND METHODS: After endodontic treatment, 30 roots of extracted human canines were embedded in resin cylinders. The post-holes were prepared at 10 mm depth and their impressions were taken using autopolymerizing acrylic resin. After casting procedures using a nickel-chromium alloy, the posts were randomly distributed into 3 groups (n=10) according ...

  18. Synthesis of the A-band polysaccharide sugar D-rhamnose requires Rmd and WbpW: identification of multiple AlgA homologues, WbpW and ORF488, in Pseudomonas aeruginosa.

    Science.gov (United States)

    Rocchetta, H L; Pacan, J C; Lam, J S

    1998-09-01

    Pseudomonas aeruginosa is capable of producing various cell-surface polysaccharides including alginate, A-band and B-band lipopolysaccharides (LPS). The D-mannuronic acid residues of alginate and the D-rhamnose (D-Rha) residues of A-band polysaccharide are both derived from the common sugar nucleotide precursor GDP-D-mannose (D-Man). Three genes, rmd, gmd and wbpW, which encode proteins involved in the synthesis of GDP-D-Rha, have been localized to the 5' end of the A-band gene cluster. In this study, WbpW was found to be homologous to phosphomannose isomerases (PMIs) and GDP-mannose pyrophosphorylases (GMPs) involved in GDP-D-Man biosynthesis. To confirm the enzymatic activity of WbpW, Escherichia coli PMI and GMP mutants deficient in the K30 capsule were complemented with wbpW, and restoration of K30 capsule production was observed. This indicates that WbpW, like AlgA, is a bifunctional enzyme that possesses both PMI and GMP activities for the synthesis of GDP-D-Man. No gene encoding a phosphomannose mutase (PMM) enzyme could be identified within the A-band gene cluster. This suggests that the PMM activity of AlgC may be essential for synthesis of the precursor pool of GDP-D-Man, which is converted to GDP-D-Rha for A-band synthesis. Gmd, a previously reported A-band enzyme, and Rmd are predicted to perform the two-step conversion of GDP-D-Man to GDP-D-Rha. Chromosomal mutants were generated in both rmd and wbpW. The Rmd mutants do not produce A-band LPS, while the WbpW mutants synthesize very low amounts of A band after 18 h of growth. The latter observation was thought to result from the presence of the functional homologue AlgA, which may compensate for the WbpW deficiency in these mutants. Thus, WbpW AlgA double mutants were constructed. These mutants also produced low levels of A-band LPS. A search of the PAO1 genome sequence identified a second AlgA homologue, designated ORF488, which may be responsible for the synthesis of GDP-D-Man in the absence of Wbp

  19. 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...

  20. 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...

  1. 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.

  2. 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

  3. 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.

  4. Minimization of steam requirements and enhancement of water-gas shift reaction with warm gas temperature CO2 removal

    Science.gov (United States)

    Siriwardane, Ranjani V; Fisher, II, James C

    2013-12-31

    The disclosure utilizes a hydroxide sorbent for humidification and CO.sub.2 removal from a gaseous stream comprised of CO and CO.sub.2 prior to entry into a water-gas-shift reactor, in order to decrease CO.sub.2 concentration and increase H.sub.2O concentration and shift the water-gas shift reaction toward the forward reaction products CO.sub.2 and H.sub.2. The hydroxide sorbent may be utilized for absorbtion of CO.sub.2 exiting the water-gas shift reactor, producing an enriched H.sub.2 stream. The disclosure further provides for regeneration of the hydroxide sorbent at temperature approximating water-gas shift conditions, and for utilizing H.sub.2O product liberated as a result of the CO.sub.2 absorption.

  5. 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.

  6. Interspecific small molecule interactions between clinical isolates of Pseudomonas aeruginosa and Staphylococcus aureus from adult cystic fibrosis patients.

    Directory of Open Access Journals (Sweden)

    Alexandre Fugère

    Full Text Available Pseudomonas aeruginosa and Staphylococcus aureus are the most prevalent pathogens in airway infections of cystic fibrosis (CF patients. We studied how these pathogens coexist and interact with each other. Clinical isolates of both species were retrieved from adult CF patients. Culture supernatants from 63 P. aeruginosa isolates triggered a wide range of biofilm-stimulatory activities when added to the culture of a control S. aureus strain. The extent of biofilm formation by S. aureus was positively correlated to the levels of the 2-alkyl-4-(1H-quinolones (AQs Pseudomonas Quinolone Signal (PQS and 2-heptyl-4-hydroxy quinoline N-oxide (HQNO produced by the P. aeruginosa isolates. Supernatants from P. aeruginosa isogenic mutants deficient in PQS and HQNO production stimulated significantly less biofilm formation by S. aureus than that seen with the parental strain PA14. When studying co-isolated pairs of P. aeruginosa and S. aureus retrieved from patients showing both pathogens, P. aeruginosa supernatants stimulated less biofilm production by the S. aureus counterparts compared to that observed using the control S. aureus strain. Accordingly, some P. aeruginosa isolates produced low levels of exoproducts and also some of the clinical S. aureus isolates were not stimulated by their co-isolates or by PA14 despite adequate production of HQNO. This suggests that colonization of the CF lungs promotes some type of strain selection, or that co-existence requires specific adaptations by either or both pathogens. Results provide insights on bacterial interactions in CF.

  7. Negative pressure wound therapy decreases mortality in a murine model of burn-wound sepsis involving Pseudomonas aeruginosa infection.

    Directory of Open Access Journals (Sweden)

    Yang Liu

    Full Text Available 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 to either NPWT or wet-to-dry (WTD treatment protocols. The bacterial loads on the wound surface were assessed during 7 d of treatment, as were the concentrations of inflammatory cytokines in the peripheral blood samples. Survival was monitored daily for 14 d after burn induction. Finally, samples of wounded skin, lung, liver, and kidney were collected and subjected to histopathological examination. RESULTS: Applying P. aeruginosa to the burn wound surface led to sepsis. During early stages of treatment, NPWT reduced the mortality of the septic animals and levels of P. aeruginosa within the burn wound compared with WTD-treated animals. Circulating levels of cytokines and cytoarchitectural abnormalities were also significantly reduced via NPWT. CONCLUSIONS: Our data indicate that NPWT inhibits the invasion and proliferation of P. aeruginosa in burn-wounded tissue and decreases early mortality in a murine model of burn-wound sepsis. These therapeutic benefits likely result from the ability of NPWT to decrease bacterial proliferation on the wound surface, reduce cytokine serum concentrations, and prevent damage to internal organs.

  8. 8 CFR 216.5 - Waiver of requirement to file joint petition to remove conditions by alien spouse.

    Science.gov (United States)

    2010-01-01

    ..., medical personnel, school officials and social service agency personnel. The Service must be satisfied... the appropriate fee required under § 103.7(b) of this Chapter. (c) (d) Interview. The service center... conditional resident parent of a battered or abused child may apply for the waiver regardless of the...

  9. In Vitro Analysis of Tobramycin-Treated Pseudomonas aeruginosa Biofilms on Cystic Fibrosis-Derived Airway Epithelial Cells▿ †

    OpenAIRE

    Anderson, Gregory G.; Moreau-Marquis, Sophie; Stanton, Bruce A.; O'Toole, George A.

    2008-01-01

    P. aeruginosa forms biofilms in the lungs of individuals with cystic fibrosis (CF); however, there have been no effective model systems for studying biofilm formation in the CF lung. We have developed a tissue culture system for growth of P. aeruginosa biofilms on CF-derived human airway cells that promotes the formation of highly antibiotic-resistant microcolonies, which produce an extracellular polysaccharide matrix and require the known abiotic biofilm formation genes flgK and pilB. Treatm...

  10. Pseudomonas aeruginosa and Achromobacter sp. clonal selection leads to successive waves of contamination of water in dental care units.

    Science.gov (United States)

    Abdouchakour, Fatima; Dupont, Chloé; Grau, Delphine; Aujoulat, Fabien; Mournetas, Patricia; Marchandin, Hélène; Parer, Sylvie; Gibert, Philippe; Valcarcel, Jean; Jumas-Bilak, Estelle

    2015-11-01

    Dental care unit waterlines (DCUWs) consist of complex networks of thin tubes that facilitate the formation of microbial biofilms. Due to the predilection toward a wet environment, strong adhesion, biofilm formation, and resistance to biocides, Pseudomonas aeruginosa, a major human opportunistic pathogen, is adapted to DCUW colonization. Other nonfermentative Gram-negative bacilli, such as members of the genus Achromobacter, are emerging pathogens found in water networks. We reported the 6.5-year dynamics of bacterial contamination of waterlines in a dental health care center with 61 dental care units (DCUs) connected to the same water supply system. The conditions allowed the selection and the emergence of clones of Achromobacter sp. and P. aeruginosa characterized by multilocus sequence typing, multiplex repetitive elements-based PCR, and restriction fragment length polymorphism in pulsed-field gel electrophoresis, biofilm formation, and antimicrobial susceptibility. One clone of P. aeruginosa and 2 clones of Achromobacter sp. colonized successively all of the DCUWs: the last colonization by P. aeruginosa ST309 led to the closing of the dental care center. Successive dominance of species and clones was linked to biocide treatments. Achromobacter strains were weak biofilm producers compared to P. aeruginosa ST309, but the coculture of P. aeruginosa and Achromobacter enhanced P. aeruginosa ST309 biofilm formation. Intraclonal genomic microevolution was observed in the isolates of P. aeruginosa ST309 collected chronologically and in Achromobacter sp. clone A. The contamination control was achieved by a complete reorganization of the dental health care center by removing the connecting tubes between DCUs. PMID:26296724

  11. Estimating Pollutant Removal Requirements for Landfills in the UK: I. Benchmark Study and Characteristics of Waste Treatment Technologies

    OpenAIRE

    Hall, D H; Drury, D.; Gronow, Jan R.; Rosevear, Alan; Pollard, Simon J. T.; Smith, Richard

    2006-01-01

    Introduction of the EU Landfill Directive is having a significant impact on waste management in the UK and in other member states that have relied on landfilling. This paper considers the length of the aftercare period required by the municipal solid waste streams that the UK will most probably generate following implementation of the Landfill Directive. Data were derived from literature to identify properties of residues from the most likely treatment processes and the prob...

  12. 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)

  13. 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

  14. Influence of peptides and proteins produced by cyanobacterium Microcystis aeruginosa on the coagulation of turbid waters

    Czech Academy of Sciences Publication Activity Database

    Šafaříková, Jana; Barešová, Magdalena; Pivokonský, Martin; Kopecká, Ivana

    2013-01-01

    Roč. 18, October (2013), s. 49-57. ISSN 1383-5866 R&D Projects: GA ČR GAP105/11/0247 Institutional research plan: CEZ:AV0Z20600510 Institutional support: RVO:67985874 Keywords : Cellular organic matter (COM) * Coagulation * Microcystis aeruginosa * Peptides/proteins * Turbidity removal Subject RIV: BK - Fluid Dynamics Impact factor: 3.065, year: 2013 http://www.sciencedirect.com/science/article/pii/S1383586613004152

  15. Excretions/Secretions from Bacteria-Pretreated Maggot Are More Effective against Pseudomonas aeruginosa Biofilms

    OpenAIRE

    Jiang, Ke-chun; Sun, Xin-juan; Wang, Wei; Liu, Lan; Cai, Ying; Chen, Yin-chen; Luo, Ning; Yu, Jian-Hua; Cai, Da-Yong; Wang, Ai-Ping

    2012-01-01

    Background Sterile larvae—maggots of the green bottle blowfly Lucilia sericata are employed as a treatment tool for various types of chronic wounds. Previous studies reported that excretions/secretions (ES) of the sterile larvae could prevent and remove the biofilms of various species of bacteria. In the present study we assessed the effect of ES from the larvae pretreated with Pseudomonas aeruginosa on the bacteria biofilms. Methods and Findings We investigated the effects of ES from the mag...

  16. 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

  17. Bactericidal effect of colistin on planktonic Pseudomonas aeruginosa is independent of hydroxyl radical formation

    DEFF Research Database (Denmark)

    Brochmann, Rikke Prejh; Toft, Anders; Ciofu, Oana;

    2014-01-01

    The bactericidal effect of several major types of antibiotics has recently been demonstrated to be dependent on the formation of toxic amounts of hydroxyl radicals (OH·) resulting from oxidative stress in metabolically active cells. Since killing by the antimicrobial peptide colistin does not...... require bacterial metabolic activity, we tested whether the bactericidal effect of colistin depends on the formation of OH·. In Pseudomonas aeruginosa cultures, OH-mediated killing by ciprofloxacin was demonstrated by decreased bacterial survival and induction of 3'-(p-hydroxyphenyl) fluorescein (HPF......· was seen in P. aeruginosa during killing by colistin, and prevention of OH· accumulation could not rescue P. aeruginosa from killing by colistin. These results therefore demonstrate that the bactericidal activity of colistin on P. aeruginosa is not dependent on oxidative stress. In conclusion...

  18. Novel Pseudomonas aeruginosa Quorum-Sensing Inhibitors Identified in an Ultra-High-Throughput Screen▿ †

    OpenAIRE

    Müh, Ute; Schuster, Martin; Heim, Roger; Singh, Ashvani; Olson, Eric R.; Greenberg, E. Peter

    2006-01-01

    The opportunistic pathogen Pseudomonas aeruginosa has two complete acyl-homoserine lactone (acyl-HSL) signaling systems, LasR-LasI and RhlR-RhlI. LasI catalyzes the synthesis of N-3-oxododecanoyl homoserine lactone (3OC12-HSL), and LasR is a transcription factor that requires 3OC12-HSL as a ligand. RhlI catalyzes the synthesis of N-butanoyl homoserine lactone (C4), and RhlR is a transcription factor that responds to C4. LasR and RhlR control the transcription of hundreds of P. aeruginosa gene...

  19. 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 ...

  20. 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

  1. 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....

  2. 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...

  3. 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...

  4. 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...

  5. 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

  6. Autogenous regulation and kinetics of induction of Pseudomonas aeruginosa recA transcription as analyzed with operon fusions

    International Nuclear Information System (INIS)

    A promoterless chloramphenicol acetyltransferase gene (cat) was used to construct recA-cat operon fusions to quantitatively examine the transcriptional regulation of the Pseudomonas aeruginosa recA gene in P. aeruginosa PAO. Wild-type P. aeruginosa containing the recA8-cat fusion was treated with methyl methanesulfonate (MMS) and showed immediate induction of chloramphenicol acetyltransferase (CAT) specific activity, whereas a recA::Tn501 mutant of P. aeruginosa containing recA8-cat showed no induction with MMS. This indicated that a functional copy of recA was required for derepression of recA transcription and that P. aeruginosa recA protein was a positive regulatory factor promoting its own expression. Compared with that in the wild type, the uninduced level of CAT in recA8-cat-containing cells was reduced by approximately one-half in the recA::Tn501 mutant, indicating that recA+-dependent spontaneous induction contributes to the uninduced levels of recA expression in P. aeruginosa. MMS (0.012%) caused recA-directed CAT synthesis to increase almost immediately, with maximum CAT activity, fourfold higher than uninduced levels, attained at 60 min postinduction. The kinetics of recA8-cat fusion activity were shown to be directly related to the MMS doses used. Another fusion called recAa1-cat, where cat was located between the two transcriptional terminators of the P. aeruginosa recA gene, also showed dose-dependent induction by MMS, but the CAT activity from recAa1-cat was only one-half of that obtained with recA8-cat under the same conditions. Treatment of recA+ P. aeruginosa containing recA8-cat with UV irradiation produced an immediate effect on recA8-cat transcription and showed little UV dose dependency at doses of 5 J/m2 or greater

  7. 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.

  8. 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...

  9. 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.

  10. [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

  11. BIOSORPTION OF TEXTILE DYE USING IMMOBILIZED BACTERIAL (PSEUDOMONAS AERUGINOSA AND FUNGAL (PHANEROCHATE CHRYSOSPORIUM CELLS

    Directory of Open Access Journals (Sweden)

    Natarajan Saravanan

    2013-01-01

    Full Text Available Wastewater containing dyes presents a serious problem due to its high toxicity which leads to creating enormous environmental pollution and ecological hazards. Therefore the removal of the high stable dyes from the textile effluents is of major importance. The purpose of this study is to remove the reactive dye Procion Blue 2G from textile dye solution by biosorption process using immobilized cells of Pseudomonas aeruginosa and Phanerochate chrysosporium. It was found that maximum dye uptake is 1.648 mg g-1 of bead for P. aeruginosa and it is 1.242 mg g-1 of bead for P. chrysosporium. Both the results are derived from higher initial dye concentration (100 mg L-1 and high cell concentration (in terms of volume of inoculum 20 mL and at low mass of biosorbent (5 g of bead. Comparatively better results are produced by the beads having the cells of P. aeruginosa than P. chrysosporium. Further, due to the cell immobilization, both the cell beads can be utilized repeatedly in continuous reactors by selecting suitable eluent in industrial scale with the advantage of avoiding wash out of cells.

  12. Influence of different laser operation regimes on the specific energy required for rock removal in oil and gas well drilling applications

    Science.gov (United States)

    Albert, Florian; Grimm, Alexander; Schmidt, Michael; Cournoyer, Alain; Briand, Martin; Galarneau, Pierre

    2009-06-01

    Although many practical hurdles remain to be addressed in the future, laser oil and gas well drilling has potential advantages over the conventional rotary drilling approach, such as a smaller footprint of the drilling rig, higher rates of penetration, reduction of downtime due to dull bits, reduction of waste caused by drilling mud, creation of a natural casing while drilling, and ability to drill in hard rock formations. One of the most promising applications is downhole laser perforation for well completion as an alternative to explosive technologies currently in use. In order to establish both the technical and economic feasibility of using lasers in oil and gas drilling operations, one can measure the laser energy required to remove a unit volume of rock. The resulting specific energy is a measure of the efficiency of the laser drilling process and depends on the rock type and the laser operation regime that determines the laser-rock interaction mechanism. In the present feasibility study, we compare the results of laser drilling tests conducted in two types of reservoir rocks, namely limestone and sandstone, at different laser wavelengths and for different laser operation regimes (continuous wave and pulsed regimes, different repetition rates and duty cycles) in terms of specific energy. We also discuss preliminary results on the influence of the temporal shape of the laser pulses in the nanosecond regime on the rock removal process as obtained with INO pulse-shaping fiber laser platform, with the objective to take advantage of the flexibility and the agility of such a laser source for drilling operations in different rock types.

  13. 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.

  14. 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.

  15. 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...

  16. 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...

  17. 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.

  18. Specific Resistance to Pseudomonas aeruginosa Infection in Zebrafish Is Mediated by the Cystic Fibrosis Transmembrane Conductance Regulator ▿ †

    Science.gov (United States)

    Phennicie, Ryan T.; Sullivan, Matthew J.; Singer, John T.; Yoder, Jeffrey A.; Kim, Carol H.

    2010-01-01

    Cystic fibrosis (CF) is a genetic disease caused by recessive mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and is associated with prevalent and chronic Pseudomonas aeruginosa lung infections. Despite numerous studies that have sought to elucidate the role of CFTR in the innate immune response, the links between CFTR, innate immunity, and P. aeruginosa infection remain unclear. The present work highlights the zebrafish as a powerful model organism for human infectious disease, particularly infection by P. aeruginosa. Zebrafish embryos with reduced expression of the cftr gene (Cftr morphants) exhibited reduced respiratory burst response and directed neutrophil migration, supporting a connection between cftr and the innate immune response. Cftr morphants were infected with P. aeruginosa or other bacterial species that are commonly associated with infections in CF patients, including Burkholderia cenocepacia, Haemophilus influenzae, and Staphylococcus aureus. Intriguingly, the bacterial burden of P. aeruginosa was found to be significantly higher in zebrafish Cftr morphants than in controls, but this phenomenon was not observed with the other bacterial species. Bacterial burden in Cftr morphants infected with a P. aeruginosa ΔLasR mutant, a quorum sensing-deficient strain, was comparable to that in control fish, indicating that the regulation of virulence factors through LasR is required for enhancement of infection in the absence of Cftr. The zebrafish system provides a multitude of advantages for studying the pathogenesis of P. aeruginosa and for understanding the role that innate immune cells, such as neutrophils, play in the host response to acute bacterial infections commonly associated with cystic fibrosis. PMID:20732993

  19. 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....

  20. 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...

  1. 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...

  2. 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...

  3. 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-...

  4. 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...

  5. 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.

  6. Oxidative stress-mediated antibacterial activity of graphene oxide and reduced graphene oxide in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Gurunathan S

    2012-11-01

    Full Text Available Sangiliyandi Gurunathan, Jae Woong Han, Ahmed Abdal Dayem, Vasuki Eppakayala, Jin-Hoi KimDepartment of Animal Biotechnology, Konkuk University, Seoul, South KoreaBackground: Graphene holds great promise for potential use in next-generation electronic and photonic devices due to its unique high carrier mobility, good optical transparency, large surface area, and biocompatibility. The aim of this study was to investigate the antibacterial effects of graphene oxide (GO and reduced graphene oxide (rGO in Pseudomonas aeruginosa. In this work, we used a novel reducing agent, betamercaptoethanol (BME, for synthesis of graphene to avoid the use of toxic materials. To uncover the impacts of GO and rGO on human health, the antibacterial activity of two types of graphene-based material toward a bacterial model P. aeruginosa was studied and compared.Methods: The synthesized GO and rGO was characterized by ultraviolet-visible absorption spectroscopy, particle-size analyzer, X-ray diffraction, scanning electron microscopy and Raman spectroscopy. Further, to explain the antimicrobial activity of graphene oxide and reduced graphene oxide, we employed various assays, such as cell growth, cell viability, reactive oxygen species generation, and DNA fragmentation.Results: Ultraviolet-visible spectra of the samples confirmed the transition of GO into graphene. Dynamic light-scattering analyses showed the average size among the two types of graphene materials. X-ray diffraction data validated the structure of graphene sheets, and high-resolution scanning electron microscopy was employed to investigate the morphologies of prepared graphene. Raman spectroscopy data indicated the removal of oxygen-containing functional groups from the surface of GO and the formation of graphene. The exposure of cells to GO and rGO induced the production of superoxide radical anion and loss of cell viability. Results suggest that the antibacterial activities are contributed to by loss of

  7. Development of flotation and nanofiltration technologies to remove cyanobacteria and cyanotoxins in drinking water treatment

    OpenAIRE

    Teixeira, Margarida Ribau

    2005-01-01

    Dissolved air flotation (DAF) and nanofiltration were optimised and integrated to remove cyanobacteria and cyanotoxins from drinking water. The removal mechanisms of the most commonly occurring cyanobacteria (cultured cells and aggregates of Microcystis aeruginosa and Plankthotrix rubescens filaments) and cyanotoxins (hepatotoxic microcystins, and neurotoxic anatoxin-a) were investigated, as well as the impact of the water background organic (NOM) and inorganic matrixes, using ...

  8. Isolation of a non-fermentative bacterium, Pseudomonas aeruginosa, using intracellular carbon for denitrification and phosphorus-accumulation and relevant metabolic mechanisms.

    Science.gov (United States)

    Liu, Hui; Wang, Qin; Sun, Yanfu; Zhou, Kangqun; Liu, Wen; Lu, Qian; Ming, Caibing; Feng, Xidan; Du, Jianjun; Jia, Xiaoshan; Li, Jun

    2016-07-01

    A newly designed pilot-scale system was developed to enrich denitrifying phosphate-accumulating organisms (DNPAOs) for nitrogen and phosphorus nutrient removal synchronously. A strain of DNPAOs was isolated and its biochemical characteristics and metabolic mechanisms of this bacterial strain were analyzed. The results showed that compared with previously reported system, this newly designed system has higher removal rates of nutrients. Removal efficiencies of NH3-N, TN, TP, and COD in actual wastewater were 82.64%, 79.62%, 87.22%, and 90.41%, respectively. Metabolic activity of DNPAOs after anoxic stage in this study even reached 94.64%. Pseudomonas aeruginosa is a strain of non-fermentative DNPAOs with strong nitrogen and phosphorus removal abilities. Study on the metabolic mechanisms suggested that intracellular PHB of P. aeruginosa plays dual roles, supplying energy for phosphorus accumulation and serving as a major carbon source for denitrification. PMID:26995616

  9. Selective trihydroxyazepane NagZ inhibitors increase sensitivity of Pseudomonas aeruginosa to β-lactams.

    Science.gov (United States)

    Mondon, Martine; Hur, Soo; Vadlamani, Grishma; Rodrigues, Prerana; Tsybina, Polina; Oliver, Antonio; Mark, Brian L; Vocadlo, David J; Blériot, Yves

    2013-12-01

    AmpC β-lactamase confers resistance to β-lactam antibiotics in many Gram negative bacteria. Inducible expression of AmpC requires an N-acetylglucosaminidase termed NagZ. Here we describe the synthesis and characterization of hydroxyazepane inhibitors of NagZ. We find that these inhibitors enhance the susceptibility of clinically relevant Pseudomonas aeruginosa to β-lactams. PMID:24136176

  10. Autoinducer-mediated regulation of rhamnolipid biosurfactant synthesis in Pseudomonas aeruginosa.

    OpenAIRE

    Ochsner, U A; Reiser, J

    1995-01-01

    The opportunistic human pathogen Pseudomonas aeruginosa produces a variety of virulence factors, including exotoxin A, elastase, alkaline protease, alginate, phospholipases, and extracellular rhamnolipids. The previously characterized rhlABR gene cluster encodes a regulatory protein (RhlR) and a rhamnosyltransferase (RhlAB), both of which are required for rhamnolipid synthesis. Another gene, rhII, has now been identified downstream of the rhlABR gene cluster. The putative RhlI protein shares ...

  11. Interspecies signalling via the Stenotrophomonas maltophilia diffusible signal factor influences biofilm formation and polymyxin tolerance in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Ryan, R.P.; Fouhy, Y.; Garcia, B.F.; Watt, S.A.; Niehaus, K.; Yang, Liang; Tolker-Nielsen, Tim; Dow, J.M.

    2008-01-01

    Interspecies signalling through the action of diffusible signal molecules can influence the behaviour of organisms growing in polymicrobial communities. Stenotrophomonas maltophilia and Pseudomonas aeruginosa occur ubiquitously in the environment and can be found together in diverse niches...... including the rhizosphere of plants and the cystic fibrosis lung. In mixed species biofilms, S. maltophilia substantially influenced the architecture of P. aeruginosa structures, which developed as extended filaments. This effect depended upon the synthesis of the diffusible signal factor (DSF) by S....... maltophilia and could be mimicked by the addition of synthetic DSF. This response of P. aeruginosa to DSF required PA1396, a sensor kinase with an input domain of related amino acid sequence to the sensory input domain of RpfC, which is responsible for DSF perception in xanthomonads. Mutation of PA1396 or...

  12. Algicidal and denitrification characterization of Acinetobacter sp. J25 against Microcystis aeruginosa and microbial community in eutrophic landscape water.

    Science.gov (United States)

    Su, Jun Feng; Ma, Min; Wei, Li; Ma, Fang; Lu, Jin Suo; Shao, Si Cheng

    2016-06-15

    Acinetobacter sp. J25 exhibited good denitrification and high algicidal activity against toxic Microcystis aeruginosa. Response surface methodology (RSM) experiments showed that the maximum algicidal ratio occurred under the following conditions: temperature, 30.46°C; M. aeruginosa density, 960,000cellsmL(-1); and inoculum, 23.75% (v/v). Of these, inoculum produced the maximum effect. In the eutrophic landscape water experiment, 10% bacterial culture was infected with M. aeruginosa cells in the landscape water. After 24days, the removal ratios of nitrate and chlorophyll-a were high, 100% and 87.86%, respectively. The denitrification rate was approximately 0.118mgNO3(-)-N·L(-1)·h(-1). Moreover, the high-throughput sequencing result showed that Acinetobacter sp. J25 was obviously beneficial for chlorophyll-a and nitrate removal performance in the eutrophic landscape water treatment. Therefore, strain J25 is promising for the simultaneous removal of chlorophyll-a and nitrate in the eutrophic landscape water treatment. PMID:27126181

  13. Tick Removal

    Science.gov (United States)

    ... ticks Tickborne diseases abroad Borrelia miyamotoi Borrelia mayonii Tick Removal Recommend on Facebook Tweet Share Compartir If ... a tick quite effectively. How to remove a tick Use fine-tipped tweezers to grasp the tick ...

  14. BIOSORPTION OF TEXTILE DYE USING IMMOBILIZED BACTERIAL (PSEUDOMONAS AERUGINOSA) AND FUNGAL (PHANEROCHATE CHRYSOSPORIUM) CELLS

    OpenAIRE

    Natarajan Saravanan; Tiruvenkadam Kannadasan; Chiya Ahmed Basha; Veerasamy Manivasagan

    2013-01-01

    Wastewater containing dyes presents a serious problem due to its high toxicity which leads to creating enormous environmental pollution and ecological hazards. Therefore the removal of the high stable dyes from the textile effluents is of major importance. The purpose of this study is to remove the reactive dye Procion Blue 2G from textile dye solution by biosorption process using immobilized cells of Pseudomonas aeruginosa and Phanerochate chrysosporium. It was found that maximum dye uptake ...

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

    DEFF Research Database (Denmark)

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

    1993-01-01

    We have compared a chronic lung infection with Pseudomonas aeruginosa embedded in alginate beads in normal and athymic rats with an acute infection with free live P. aeruginosa bacteria. The following parameters were observed and described: mortality, macroscopic and microscopic pathologic changes...

  16. Novel Targets for Treatment of Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Morten; Alhede, Maria; Bjarnsholt, Thomas

    2014-01-01

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

  17. 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...

  18. 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)

  19. 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.

  20. 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.

  1. 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...

  2. 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.

  3. Proteomics of the oxidative stress response induced by hydrogen peroxide and paraquat reveals a novel AhpC-like protein in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Hare, Nathan J; Scott, Nichollas E; Shin, Eun Hye H;

    2011-01-01

    Pseudomonas aeruginosa is a ubiquitous pathogen most typically associated with wound infections, but also the main cause of mortality in patients suffering from cystic fibrosis (CF). The ability to adapt to oxidative stress associated with host immune defense may be one mechanism by which P....... aeruginosa establishes infection in the cystic fibrosis lung and eventually out-competes other pathogenic bacteria to persist into chronic infection. We utilized a proteomics approach to identify the proteins associated with the oxidative stress response of P. aeruginosa PAO1 to hydrogen peroxide...... by hypothetical protein PA3529 following treatment with 10 mM H(2) O(2) . AhpC belongs to the 2-Cys peroxiredoxin family and is a redox enzyme responsible for removing peroxides in bacterial cells. MS analysis showed that PA3529 was altered by the formation of a dimer via a disulfide bond in a manner analogous...

  4. 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.

  5. 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%.

  6. Enantioselective changes in oxidative stress and toxin release in Microcystis aeruginosa exposed to chiral herbicide diclofop acid

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Jing [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Natural Research and Environmental Sciences, Zhejiang University, Hangzhou 310058 (China); Zhang, Ying [Department of Environmental Science, East China Normal University, Shanghai 200241 (China); Chen, Shengwen [School of Urban Development and Environment Engineering, Shanghai Second Polytechnic University, Shanghai 201209 (China); Liu, Chaonan; Zhu, Yongqiang [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Liu, Weiping, E-mail: wliu@zju.edu.cn [MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Natural Research and Environmental Sciences, Zhejiang University, Hangzhou 310058 (China)

    2014-01-15

    Highlights: •The first study on enantioselective oxidative stress and toxin release from Microcystis aeruginosa. •Provide information for the R-enantiomer poses more oxidative stress than the S-enantiomer. •Lifecycle analysis of chiral pollutants needs more attention in environmental assessment. -- Abstract: Enantioselective oxidative stress and toxin release from Microcystis aeruginosa after exposure to the chiral herbicide diclofop acid were investigated. Racemic diclofop acid, R-diclofop acid and S-diclofop acid induced reactive oxygen species (ROS) generation, increased the concentration of malondialdehyde (MDA), enhanced the activity of superoxide dismutase (SOD) and triggered toxin release in M. aeruginosa to varying degrees. The increase in MDA concentration and SOD activity in M. aeruginosa occurred sooner after exposure to diclofop acid than when the cyanobacteria was exposed to either the R- and the S-enantiomer. In addition, enantioselective toxicity of the enantiomers was observed. The R-enantiomer trigged more ROS generation, more SOD activity and more toxin synthesis and release in M. aeruginosa cells than the S-enantiomer. Diclofop acid and its R-enantiomer may collapse the transmembrane proton gradient and destroy the cell membrane through lipid peroxidation and free radical oxidation, whereas the S-enantiomer did not demonstrate such action. R-diclofop acid inhibits the growth of M. aeruginosa in the early stage, but ultimately induced greater toxin release, which has a deleterious effect on the water column. These results indicate that more comprehensive study is needed to determine the environmental safety of the enantiomers, and application of chiral pesticides requires more direct supervision and training. Additionally, lifecycle analysis of chiral pollutants in aquatic system needs more attention to aide in the environmental assessment of chiral pesticides.

  7. Tobramycin at subinhibitory concentration inhibits the RhlI/R quorum sensing system in a Pseudomonas aeruginosa environmental isolate

    Directory of Open Access Journals (Sweden)

    Venturi Vittorio

    2010-06-01

    Full Text Available Abstract Background Antibiotics are not only small molecules with therapeutic activity in killing or inhibiting microbial growth, but can also act as signaling molecules affecting gene expression in bacterial communities. A few studies have demonstrated the effect of tobramycin as a signal molecule on gene expression at the transcriptional level and its effect on bacterial physiology and virulence. These have shown that subinhibitory concentrations (SICs of tobramycin induce biofilm formation and enhance the capabilities of P. aeruginosa to colonize specific environments. Methods Environmental P. aeruginosa strain PUPa3 was grown in the presence of different concentrations of tobramycin and it was determined at which highest concentration SIC, growth, total protein levels and translation efficiency were not affected. At SIC it was then established if phenotypes related to cell-cell signaling known as quorum sensing were altered. Results In this study it was determined whether tobramycin sensing/response at SICs was affecting the two independent AHL QS systems in an environmental P. aeruginosa strain. It is reasonable to assume that P. aeruginosa encounters tobramycin in nature since it is produced by niche mate Streptomyces tenebrarius. It was established that SICs of tobramycin inhibited the RhlI/R system by reducing levels of C4-HSL production. This effect was not due to a decrease of rhlI transcription and required tobramycin-ribosome interaction. Conclusions Tobramycin signaling in P. aeruginosa occurs and different strains can have a different response. Understanding the tobramycin response by an environmental P. aeruginosa will highlight possible inter-species signalling taking place in nature and can possible also have important implications in the mode of utilization for human use of this very important antibiotic.

  8. Virulence properties of Pseudomonas aeruginosa lacking the extreme-stress sigma factor AlgU (sigmaE).

    Science.gov (United States)

    Yu, H; Boucher, J C; Hibler, N S; Deretic, V

    1996-07-01

    A discerning feature of Pseudomonas aeruginosa strains causing chronic endobronchial infections in cystic fibrosis is their conversion into the mucoid, exopolysaccharide alginate-overproducing phenotype. This morphologically prominent change is caused by mutations which upregulate AlgU (sigma(E)), a novel extreme-stress sigma factor with functional equivalents in gram-negative organisms. In this work, we investigated the role of algU in P. aeruginosa sensitivity to reactive oxygen intermediates, killing by phagocytic cells, and systemic virulence of this bacterium. Inactivation of algU in P. aeruginosa PA01 increased its susceptibility to killing by chemically or enzymatically generated halogenated reactive oxygen intermediates and reduced its survival in bactericidal assays with J774 murine macrophages and human neutrophils. Surprisingly, inactivation of algU caused increased systemic virulence of P. aeruginosa in mouse models of acute infection. The increased lethality of the algU-deficient strain was also observed in the endotoxin-resistant C3H/HeJ mice. Only minor differences between algU+ and algU mutant cells in their sensitivity to human serum were observed, and no differences in their lipopolysaccharide profiles were detected. Intriguingly, while inactivation of algU downregulated five polypeptides it also upregulated the expression of seven polypeptides as determined by two-dimensional gel analyses, suggesting that algU plays both a positive and a negative role in gene expression in P. aeruginosa. While the observation that algU inactivation increases systemic virulence in P. aeruginosa requires further explanation, this phenomenon contrasts with the apparent selection for strains with upregulated AlgU during colonization of the cystic fibrosis lung and suggests opposing roles for this system in chronic and acute infections. PMID:8698507

  9. Candida albicans ethanol stimulates Pseudomonas aeruginosa WspR-controlled biofilm formation as part of a cyclic relationship involving phenazines.

    Directory of Open Access Journals (Sweden)

    Annie I Chen

    2014-10-01

    Full Text Available In chronic infections, pathogens are often in the presence of other microbial species. For example, Pseudomonas aeruginosa is a common and detrimental lung pathogen in individuals with cystic fibrosis (CF and co-infections with Candida albicans are common. Here, we show that P. aeruginosa biofilm formation and phenazine production were strongly influenced by ethanol produced by the fungus C. albicans. Ethanol stimulated phenotypes that are indicative of increased levels of cyclic-di-GMP (c-di-GMP, and levels of c-di-GMP were 2-fold higher in the presence of ethanol. Through a genetic screen, we found that the diguanylate cyclase WspR was required for ethanol stimulation of c-di-GMP. Multiple lines of evidence indicate that ethanol stimulates WspR signaling through its cognate sensor WspA, and promotes WspR-dependent activation of Pel exopolysaccharide production, which contributes to biofilm maturation. We also found that ethanol stimulation of WspR promoted P. aeruginosa colonization of CF airway epithelial cells. P. aeruginosa production of phenazines occurs both in the CF lung and in culture, and phenazines enhance ethanol production by C. albicans. Using a C. albicans adh1/adh1 mutant with decreased ethanol production, we found that fungal ethanol strongly altered the spectrum of P. aeruginosa phenazines in favor of those that are most effective against fungi. Thus, a feedback cycle comprised of ethanol and phenazines drives this polymicrobial interaction, and these relationships may provide insight into why co-infection with both P. aeruginosa and C. albicans has been associated with worse outcomes in cystic fibrosis.

  10. Enantioselective changes in oxidative stress and toxin release in Microcystis aeruginosa exposed to chiral herbicide diclofop acid

    International Nuclear Information System (INIS)

    Highlights: •The first study on enantioselective oxidative stress and toxin release from Microcystis aeruginosa. •Provide information for the R-enantiomer poses more oxidative stress than the S-enantiomer. •Lifecycle analysis of chiral pollutants needs more attention in environmental assessment. -- Abstract: Enantioselective oxidative stress and toxin release from Microcystis aeruginosa after exposure to the chiral herbicide diclofop acid were investigated. Racemic diclofop acid, R-diclofop acid and S-diclofop acid induced reactive oxygen species (ROS) generation, increased the concentration of malondialdehyde (MDA), enhanced the activity of superoxide dismutase (SOD) and triggered toxin release in M. aeruginosa to varying degrees. The increase in MDA concentration and SOD activity in M. aeruginosa occurred sooner after exposure to diclofop acid than when the cyanobacteria was exposed to either the R- and the S-enantiomer. In addition, enantioselective toxicity of the enantiomers was observed. The R-enantiomer trigged more ROS generation, more SOD activity and more toxin synthesis and release in M. aeruginosa cells than the S-enantiomer. Diclofop acid and its R-enantiomer may collapse the transmembrane proton gradient and destroy the cell membrane through lipid peroxidation and free radical oxidation, whereas the S-enantiomer did not demonstrate such action. R-diclofop acid inhibits the growth of M. aeruginosa in the early stage, but ultimately induced greater toxin release, which has a deleterious effect on the water column. These results indicate that more comprehensive study is needed to determine the environmental safety of the enantiomers, and application of chiral pesticides requires more direct supervision and training. Additionally, lifecycle analysis of chiral pollutants in aquatic system needs more attention to aide in the environmental assessment of chiral pesticides

  11. A Phytoanticipin Derivative, Sodium Houttuyfonate, Induces in Vitro Synergistic Effects with Levofloxacin against Biofilm Formation by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Jing Shao

    2012-09-01

    Full Text Available Antibiotic resistance has become the main deadly factor in infections, as bacteria can protect themselves by hiding in a self-constructed biofilm. Consequently, more attention is being paid to the search for “non-antibiotic drugs” to solve this problem. Phytoanticipins, the natural antibiotics from plants, could be a suitable alternative, but few works on this aspect have been reported. In this study, a preliminary study on the synergy between sodium houttuyfonate (SH and levofloxacin (LFX against the biofilm formation of Pseudomonas aeruginosa was performed. The minimal inhibitory concentrations (MIC of LFX and SH, anti-biofilm formation and synergistic effect on Pseudomonas aeruginosa, and quantification of alginate were determined by the microdilution method, crystal violet (CV assay, checkerboard method, and hydroxybiphenyl colorimetry. The biofilm morphology of Pseudomonas aeruginosa was observed by fluorescence microscope and scanning electric microscope (SEM. The results showed that: (i LFX and SH had an obvious synergistic effect against Pseudomonas aeruginosa with MIC values of 0.25 μg/mL and 128 μg/mL, respectively; (ii ½ × MIC SH combined with 2 × MIC LFX could suppress the biofilm formation of Pseudomonas aeruginosa effectively, with up to 73% inhibition; (iii the concentration of alginate decreased dramatically by a maximum of 92% after treatment with the combination of antibiotics; and (iv more dead cells by fluorescence microscope and more removal of extracellular polymeric structure (EPS by SEM were observed after the combined treatment of LFX and SH. Our experiments demonstrate the promising future of this potent antimicrobial agent against biofilm-associated infections.

  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. Removal of cyanobacteria and cyanotoxins from drinking water by powdered activated carbon adsorption/ultrafiltration

    OpenAIRE

    Campinas, Margarida Páscoa

    2009-01-01

    Tese dout., Ciências e Tecnologias do Ambiente, Universidade do Algarve, 2009 PAC/UF was investigated to remove the cyanobacterium Microcysis aeruginosa and microcystins, focusing on toxins adsorption onto PAC and the combined effect of the water organic and inorganic matrices, the cells removal and lysis by UF, and PAC contribution to membrane fouling control and microcystins removal by PAC/UF. The fine-grade mesoporous PAC presented high capacity and fast kinetics for microc...

  14. 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.

  15. Pseudomonas aeruginosa Acquisition in Cystic Fibrosis Patients in Context of Otorhinolaryngological Surgery or Dentist Attendance: Case Series and Discussion of Preventive Concepts

    Directory of Open Access Journals (Sweden)

    Jochen G. Mainz

    2015-01-01

    Full Text Available Introduction. P. aeruginosa is the primary cause for pulmonary destruction and premature death in cystic fibrosis (CF. Therefore, prevention of airway colonization with the pathogen, ubiquitously present in water, is essential. Infection of CF patients with P. aeruginosa after dentist treatment was proven and dental unit waterlines were identified as source, suggesting prophylactic measures. For their almost regular sinonasal involvement, CF patients often require otorhinolaryngological (ORL attendance. Despite some fields around ORL-procedures with comparable risk for acquisition of P. aeruginosa, such CF cases have not yet been reported. We present four CF patients, who primarily acquired P. aeruginosa around ORL surgery, and one around dentist treatment. Additionally, we discuss risks and preventive strategies for CF patients undergoing ORL-treatment. Perils include contact to pathogen-carriers in waiting rooms, instrumentation, suction, drilling, and flushing fluid, when droplets containing pathogens can be nebulized. Postsurgery mucosal damage and debridement impair sinonasal mucociliary clearance, facilitating pathogen proliferation and infestation. Therefore, sinonasal surgery and dentist treatment of CF patients without chronic P. aeruginosa colonization must be linked to repeated microbiological assessment. Further studies must elaborate whether all CF patients undergoing ORL-surgery require antipseudomonal prophylaxis, including nasal lavages containing antibiotics. Altogether, this underestimated risk requires structured prevention protocols.

  16. Pseudomonas aeruginosa Acquisition in Cystic Fibrosis Patients in Context of Otorhinolaryngological Surgery or Dentist Attendance: Case Series and Discussion of Preventive Concepts.

    Science.gov (United States)

    Mainz, Jochen G; Gerber, Andrea; Lorenz, Michael; Michl, Ruth; Hentschel, Julia; Nader, Anika; Beck, James F; Pletz, Mathias W; Mueller, Andreas H

    2015-01-01

    Introduction. P. aeruginosa is the primary cause for pulmonary destruction and premature death in cystic fibrosis (CF). Therefore, prevention of airway colonization with the pathogen, ubiquitously present in water, is essential. Infection of CF patients with P. aeruginosa after dentist treatment was proven and dental unit waterlines were identified as source, suggesting prophylactic measures. For their almost regular sinonasal involvement, CF patients often require otorhinolaryngological (ORL) attendance. Despite some fields around ORL-procedures with comparable risk for acquisition of P. aeruginosa, such CF cases have not yet been reported. We present four CF patients, who primarily acquired P. aeruginosa around ORL surgery, and one around dentist treatment. Additionally, we discuss risks and preventive strategies for CF patients undergoing ORL-treatment. Perils include contact to pathogen-carriers in waiting rooms, instrumentation, suction, drilling, and flushing fluid, when droplets containing pathogens can be nebulized. Postsurgery mucosal damage and debridement impair sinonasal mucociliary clearance, facilitating pathogen proliferation and infestation. Therefore, sinonasal surgery and dentist treatment of CF patients without chronic P. aeruginosa colonization must be linked to repeated microbiological assessment. Further studies must elaborate whether all CF patients undergoing ORL-surgery require antipseudomonal prophylaxis, including nasal lavages containing antibiotics. Altogether, this underestimated risk requires structured prevention protocols. PMID:25866686

  17. Staphylococcus aureus and Pseudomonas aeruginosa express and secrete human surfactant proteins.

    Directory of Open Access Journals (Sweden)

    Lars Bräuer

    Full Text Available Surfactant proteins (SP, originally known from human lung surfactant, are essential to proper respiratory function in that they lower the surface tension of the alveoli. They are also important components of the innate immune system. The functional significance of these proteins is currently reflected by a very large and growing number of publications. The objective goal of this study was to elucidate whether Staphylococcus aureus and Pseudomonas aeruginosa is able to express surfactant proteins. 10 different strains of S. aureus and P. aeruginosa were analyzed by means of RT-PCR, Western blot analysis, ELISA, immunofluorescence microscopy and immunoelectron microscopy. The unexpected and surprising finding revealed in this study is that different strains of S. aureus and P. aeruginosa express and secrete proteins that react with currently commercially available antibodies to known human surfactant proteins. Our results strongly suggest that the bacteria are either able to express 'human-like' surfactant proteins on their own or that commercially available primers and antibodies to human surfactant proteins detect identical bacterial proteins and genes. The results may reflect the existence of a new group of bacterial surfactant proteins and DNA currently lacking in the relevant sequence and structure databases. At any rate, our knowledge of human surfactant proteins obtained from immunological and molecular biological studies may have been falsified by the presence of bacterial proteins and DNA and therefore requires critical reassessment.

  18. Staphylococcus aureus and Pseudomonas aeruginosa express and secrete human surfactant proteins.

    Science.gov (United States)

    Bräuer, Lars; Schicht, Martin; Worlitzsch, Dieter; Bensel, Tobias; Sawers, R Gary; Paulsen, Friedrich

    2013-01-01

    Surfactant proteins (SP), originally known from human lung surfactant, are essential to proper respiratory function in that they lower the surface tension of the alveoli. They are also important components of the innate immune system. The functional significance of these proteins is currently reflected by a very large and growing number of publications. The objective goal of this study was to elucidate whether Staphylococcus aureus and Pseudomonas aeruginosa is able to express surfactant proteins. 10 different strains of S. aureus and P. aeruginosa were analyzed by means of RT-PCR, Western blot analysis, ELISA, immunofluorescence microscopy and immunoelectron microscopy. The unexpected and surprising finding revealed in this study is that different strains of S. aureus and P. aeruginosa express and secrete proteins that react with currently commercially available antibodies to known human surfactant proteins. Our results strongly suggest that the bacteria are either able to express 'human-like' surfactant proteins on their own or that commercially available primers and antibodies to human surfactant proteins detect identical bacterial proteins and genes. The results may reflect the existence of a new group of bacterial surfactant proteins and DNA currently lacking in the relevant sequence and structure databases. At any rate, our knowledge of human surfactant proteins obtained from immunological and molecular biological studies may have been falsified by the presence of bacterial proteins and DNA and therefore requires critical reassessment. PMID:23349731

  19. Pseudomonas aeruginosa produces phosphatidyltris(hydroxymethyl)aminomethane and derivatives when grown in Tris-buffered medium.

    Science.gov (United States)

    Abbes, Imen; Rihouey, Christophe; Hardouin, Julie; Dé, Emmanuelle; Jouenne, Thierry; Alexandre, Stéphane

    2016-08-01

    For optimal growth of a microorganism, the pH of the culture medium should be set at an optimum value. For that reason, growth media require buffering agents. We show in this study that, when grown in a medium supplemented with tris(hydroxymethyl)aminomethane (Tris), Pseudomonas aeruginosa is able to use this organic compound to produce new phospholipids. We thus pointed out that phosphatidyltris(hydroxymethyl)aminomethane as well as diphosphatidyltris(hydroxymethyl)aminomethane was detected in membrane lipid extracts of bacteria grown in Tris-buffered medium. Moreover, the amounts of lysoglycerophospholipids in the lipidome of P. aeruginosa grown in Tris-buffered medium increased leading to the presence of lysophosphatidylglycerol and lysophosphatidyltris(hydroxymethyl)aminomethane as well as other lysophospholipid derivatives. Finally, we investigated the effect of the presence of these exogenous phospholipids on the susceptibility of P. aeruginosa to some antibiotics. We observed a decrease of the minimal inhibitory concentrations of different antibiotic families, i.e., fluoroquinolones, aminoglycosides, ß-lactams and polymyxins, proving the importance of the buffer choice for growth medium and its impact on the lipidome. PMID:27126915

  20. LuxR homolog-independent gene regulation by acyl-homoserine lactones in Pseudomonas aeruginosa.

    Science.gov (United States)

    Chugani, Sudha; Greenberg, Everett Peter

    2010-06-01

    Pseudomonas aeruginosa quorum control of gene expression involves three LuxR-type signal receptors LasR, RhlR, and QscR that respond to the LasI- and RhlI-generated acyl-homoserine lactone (acyl-HSL) signals 3OC12-HSL and C4-HSL. We found that a LasR-RhlR-QscR triple mutant responds to acyl-HSLs by regulating at least 37 genes. LuxR homolog-independent activation of the representative genes antA and catB also occurs in the wild type. Expression of antA was influenced the most by C10-HSL and to a lesser extent by other acyl-HSLs, including the P. aeruginosa 3OC12-HSL and C4-HSL signals. The ant and cat operons encode enzymes for the degradation of anthranilate to tricarboxylic acid cycle intermediates. Our results indicate that LuxR homolog-independent acyl-HSL control of the ant and cat operons occurs via regulation of antR, which codes for the transcriptional activator of the ant operon. Although P. aeruginosa has multiple pathways for anthranilate synthesis, one pathway-the kynurenine pathway for tryptophan degradation-is required for acyl-HSL activation of the ant operon. The kynurenine pathway is also the critical source of anthranilate for energy metabolism via the antABC gene products, as well as the source of anthranilate for synthesis of the P. aeruginosa quinolone signal. Our discovery of LuxR homolog-independent responses to acyl-HSLs provides insight into acyl-HSL signaling. PMID:20498077

  1. Metabolic pathways of Pseudomonas aeruginosa involved in competition with respiratory bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Marie eBeaume

    2015-04-01

    Full Text Available Background: Chronic airway infection by Pseudomonas aeruginosa considerably contributes to lung tissue destruction and impairment of pulmonary function in cystic-fibrosis (CF patients. Complex interplays between P. aeruginosa and other co-colonizing pathogens including Staphylococcus aureus, Burkholderia spp and Klebsiella pneumoniae may be crucial for pathogenesis and disease progression.Methods: We generated a library of PA14 transposon insertion mutants to identify P. aeruginosa genes required for exploitative and direct competitions with S. aureus, B. cenocepacia, and K. pneumoniae. Results: Whereas wild type PA14 inhibited S. aureus growth, two transposon insertions located in pqsC and carB, resulted in reduced growth inhibition. PqsC is involved in the synthesis of 4-hydroxy-2-alkylquinolines (HAQs, a family of molecules having antibacterial properties, while carB is a key gene in pyrimidine biosynthesis. The carB mutant was also unable to grow in the presence of B. cepacia and K. pneumoniae but not E. coli and S. epidermidis. We further identified a transposon insertion in purF, encoding a key enzyme of purine metabolism. This mutant displayed a severe growth deficiency in the presence of Gram-negative but not of Gram-positive bacteria. We identified a beneficial interaction in a bioA transposon mutant, unable to grow on rich medium. This growth defect could be restored either by addition of biotin or by co-culturing the mutant in the presence of K. pneumoniae or E. coli.Conclusions: Complex interactions take place between the various bacterial species colonizing CF-lungs. This work identified both detrimental and beneficial interactions occurring between P. aeruginosa and three other respiratory pathogens involving several major metabolic pathways. Manipulating these pathways could be used to interfere with bacterial interactions and influence the colonization by respiratory pathogens.

  2. Differential infection properties of three inducible prophages from an epidemic strain of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    James Chloe E

    2012-09-01

    Full Text Available Abstract Background Pseudomonas aeruginosa is the most common bacterial pathogen infecting the lungs of patients with cystic fibrosis (CF. The Liverpool Epidemic Strain (LES is transmissible, capable of superseding other P. aeruginosa populations and is associated with increased morbidity. Previously, multiple inducible prophages have been found to coexist in the LES chromosome and to constitute a major component of the accessory genome not found in other sequenced P. aerugionosa strains. LES phages confer a competitive advantage in a rat model of chronic lung infection and may, therefore underpin LES prevalence. Here the infective properties of three LES phages were characterised. Results This study focuses on three of the five active prophages (LESφ2, LESφ3 and LESφ4 that are members of the Siphoviridae. All were induced from LESB58 by norfloxacin. Lytic production of LESφ2 was considerably higher than that of LESφ3 and LESφ4. Each phage was capable of both lytic and lysogenic infection of the susceptible P. aeruginosa host, PAO1, producing phage-specific plaque morphologies. In the PAO1 host background, the LESφ2 prophage conferred immunity against LESφ3 infection and reduced susceptibility to LESφ4 infection. Each prophage was less stable in the PAO1 chromosome with substantially higher rates of spontaneous phage production than when residing in the native LESB58 host. We show that LES phages are capable of horizontal gene transfer by infecting P. aeruginosa strains from different sources and that type IV pili are required for infection by all three phages. Conclusions Multiple inducible prophages with diverse infection properties have been maintained in the LES genome. Our data suggest that LESφ2 is more sensitive to induction into the lytic cycle or has a more efficient replicative cycle than the other LES phages.

  3. Biochemical Characterization of the Split Class II Ribonucleotide Reductase from Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Mikael Crona

    Full Text Available The opportunistic pathogen Pseudomonas aeruginosa can grow under both aerobic and anaerobic conditions. Its flexibility with respect to oxygen load is reflected by the fact that its genome encodes all three existing classes of ribonucleotides reductase (RNR: the oxygen-dependent class I RNR, the oxygen-indifferent class II RNR, and the oxygen-sensitive class III RNR. The P. aeruginosa class II RNR is expressed as two separate polypeptides (NrdJa and NrdJb, a unique example of a split RNR enzyme in a free-living organism. A split class II RNR is also found in a few closely related γ-Proteobacteria. We have characterized the P. aeruginosa class II RNR and show that both subunits are required for formation of a biologically functional enzyme that can sustain vitamin B12-dependent growth. Binding of the B12 coenzyme as well as substrate and allosteric effectors resides in the NrdJa subunit, whereas the NrdJb subunit mediates efficient reductive dithiol exchange during catalysis. A combination of activity assays and activity-independent methods like surface plasmon resonance and gas phase electrophoretic macromolecule analysis suggests that the enzymatically active form of the enzyme is a (NrdJa-NrdJb2 homodimer of heterodimers, and a combination of hydrogen-deuterium exchange experiments and molecular modeling suggests a plausible region in NrdJa that interacts with NrdJb. Our detailed characterization of the split NrdJ from P. aeruginosa provides insight into the biochemical function of a unique enzyme known to have central roles in biofilm formation and anaerobic growth.

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

    Science.gov (United States)

    Vital-Lopez, Francisco G; Reifman, Jaques; Wallqvist, Anders

    2015-10-01

    A hallmark of Pseudomonas aeruginosa is its ability to establish biofilm-based infections that are difficult to eradicate. Biofilms are less susceptible to host inflammatory and immune responses and have higher antibiotic tolerance than free-living planktonic cells. Developing treatments against biofilms requires an understanding of bacterial biofilm-specific physiological traits. Research efforts have started to elucidate the intricate mechanisms underlying biofilm development. However, many aspects of these mechanisms are still poorly understood. Here, we addressed questions regarding biofilm metabolism using a genome-scale kinetic model of the P. aeruginosa metabolic network and gene expression profiles. Specifically, we computed metabolite concentration differences between known mutants with altered biofilm formation and the wild-type strain to predict drug targets against P. aeruginosa biofilms. We also simulated the altered metabolism driven by gene expression changes between biofilm and stationary growth-phase planktonic cultures. Our analysis suggests that the synthesis of important biofilm-related molecules, such as the quorum-sensing molecule Pseudomonas quinolone signal and the exopolysaccharide Psl, is regulated not only through the expression of genes in their own synthesis pathway, but also through the biofilm-specific expression of genes in pathways competing for precursors to these molecules. Finally, we investigated why mutants defective in anthranilate degradation have an impaired ability to form biofilms. Alternative to a previous hypothesis that this biofilm reduction is caused by a decrease in energy production, we proposed that the dysregulation of the synthesis of secondary metabolites derived from anthranilate and chorismate is what impaired the biofilms of these mutants. Notably, these insights generated through our kinetic model-based approach are not accessible from previous constraint-based model analyses of P. aeruginosa biofilm

  5. 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...

  6. 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

  7. 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...

  8. 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

  9. 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....

  10. 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%.

  11. 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...

  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. Tattoo removal.

    Science.gov (United States)

    Adatto, Maurice A; Halachmi, Shlomit; Lapidoth, Moshe

    2011-01-01

    Over 50,000 new tattoos are placed each year in the United States. Studies estimate that 24% of American college students have tattoos and 10% of male American adults have a tattoo. The rising popularity of tattoos has spurred a corresponding increase in tattoo removal. Not all tattoos are placed intentionally or for aesthetic reasons though. Traumatic tattoos due to unintentional penetration of exogenous pigments can also occur, as well as the placement of medical tattoos to mark treatment boundaries, for example in radiation therapy. Protocols for tattoo removal have evolved over history. The first evidence of tattoo removal attempts was found in Egyptian mummies, dated to have lived 4,000 years BC. Ancient Greek writings describe tattoo removal with salt abrasion or with a paste containing cloves of white garlic mixed with Alexandrian cantharidin. With the advent of Q-switched lasers in the late 1960s, the outcomes of tattoo removal changed radically. In addition to their selective absorption by the pigment, the extremely short pulse duration of Q-switched lasers has made them the gold standard for tattoo removal. PMID:21865802

  3. 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.

  4. 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 ...

  5. The Study of Synergistic Effects of n.butanolic Cyclamen coum Extract and Ciprofloxacin on inhibition of Pseudomonas aeruginosa biofilm formation

    Directory of Open Access Journals (Sweden)

    ahya abdi ali

    2015-02-01

    Full Text Available   Introduction : Infections caused by Pseudomonas aeruginosa biofilm are the major causes of death in patients with cystic fibrosis (CF. Some studies revealed that biofilms are resistant to several antibiotics because of their impermeable structures. In order to re-sensitize bacteria to different antibiotics, biofilm formation should be inhibited. In this research, evaluation of antibiofilm activity of n-butanolic Cyclamen coum extract as a medici­nal plant from Myrsinaceae family, in combination with ciprofloxacin was carried out.   Materials and method s: The biofilm formation ability by P. aeruginosa PAO1 and one clinically isolated P. aeruginosa (PA214 was confirmed by microtiter plate method. Extraction of the tubers of Cyclamen coum was done by fractionation method . The antibiofilm and antibacterial properties of n-butanolic C. coum extract (which includes saponin compounds alone and in combination with ciprofloxacin by using microdilution and crystal violet methods were examined. The cytotoxicity effect of the n-butanolic extract on HT-29 cells was assayed by MTT (3- (4,5-dimethylthiazol-2-yl -2,5-diphenyl-tetrazolium bromide test.   Results : The biofilm formation ability by P. aeruginosa strains was quantitatively confirmed. Saponin content of the n-butanolic C.coum extract was 156 µg/mL. The extract revealed antibacterial activity against the growth of planktonic P. aeruginosa strains. The combination of n-butanolic C.coum extract and ciprofloxacin significantly inhibited P.aeruginosa biofilm formation (ΣFBIC = 0.5. The n-butanolic C.coum extract showed insignificant cytotoxic effect against HT-29 human cancer cell line after 48 hours and 72 hours incubation .   Discussion and conclusion : It can be concluded that n-butanolic C.coum extract in combination with ciprofloxacin significantly revealed antibiofilm activity against P. aeruginosa biofilm however, further clinical investigations are required.

  6. Utility of lytic bacteriophage in the treatment of multidrug-resistant Pseudomonas aeruginosa septicemia in mice

    Directory of Open Access Journals (Sweden)

    Vinodkumar C

    2008-07-01

    Full Text Available Drug resistance is the major cause of increase in morbidity and mortality in neonates. One thousand six hundred forty-seven suspected septicemic neonates were subjected for microbiological analysis over a period of 5 years. Forty-two P. aeruginosa were isolated and the antibiogram revealed that 28 P. aeruginosa were resistant to almost all the common drugs used (multidrug-resistant. The emergence of antibiotic-resistant bacterial strains is one of the most critical problems of modern medicine. As a result, a novel and most effective approaches for treating infection caused by multidrug-resistant bacteria are urgently required. In this context, one intriguing approach is to use bacteriophages (viruses that kill bacteria in the treatment of infection caused by drug-resistant bacteria. In the present study, the utility of lytic bacteriophages to rescue septicemic mice with multidrug-resistant (MDR P. aeruginosa infection was evaluated. MDR P. aeruginosa was used to induce septicemia in mice by intraperitoneal (i.p. injection of 10 7 CFU. The resulting bacteremia was fatal within 48 hrs. The phage strain used in this study had lytic activity against a wide range of clinical isolates of MDR P. aeruginosa. A single i.p. injection of 3 x 10 9 PFU of the phage strain, administered 45 min after the bacterial challenge, was sufficient to rescue 100% of the animals. Even when treatment was delayed to the point where all animals were moribund, approximately 50% of them were rescued by a single injection of this phage preparation. The ability of this phage to rescue septicemic mice was demonstrated to be due to the functional capabilities of the phage and not to a nonspecific immune effect. The rescue of septicemic mice could be affected only by phage strains able to grow in vitro on the bacterial host used to infect the animals and when such strains are heat-inactivated, they lose their ability to rescue the infected mice. Multidrug-resistant bacteria have

  7. Hair removal

    DEFF Research Database (Denmark)

    Haedersdal, Merete; Haak, Christina S

    2011-01-01

    suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair......Hair removal with optical devices has become a popular mainstream treatment that today is considered the most efficient method for the reduction of unwanted hair. Photothermal destruction of hair follicles constitutes the fundamental concept of hair removal with red and near-infrared wavelengths......, white skin, and a normal hormonal status. Currently, no method of lifelong permanent hair eradication is available, and it is important that patients have realistic expectations. Substantial evidence has been found for short-term hair removal efficacy of up to 6 months after treatment with the available...

  8. Hair Removal

    DEFF Research Database (Denmark)

    Hædersdal, Merete

    2011-01-01

    suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair......Hair removal with optical devices has become a popular mainstream treatment that today is considered the most efficient method for the reduction of unwanted hair. Photothermal destruction of hair follicles constitutes the fundamental concept of hair removal with red and near-infrared wavelengths......, white skin, and a normal hormonal status. Currently, no method of lifelong permanent hair eradication is available, and it is important that patients have realistic expectations. Substantial evidence has been found for short-term hair removal efficacy of up to 6 months after treatment with the available...

  9. Genomic analysis and temperature-dependent transcriptome profiles of the rhizosphere originating strain Pseudomonas aeruginosa M18

    Directory of Open Access Journals (Sweden)

    He Ya-Wen

    2011-08-01

    Full Text Available Abstract Background Our previously published reports have described an effective biocontrol agent named Pseudomonas sp. M18 as its 16S rDNA sequence and several regulator genes share homologous sequences with those of P. aeruginosa, but there are several unusual phenotypic features. This study aims to explore its strain specific genomic features and gene expression patterns at different temperatures. Results The complete M18 genome is composed of a single chromosome of 6,327,754 base pairs containing 5684 open reading frames. Seven genomic islands, including two novel prophages and five specific non-phage islands were identified besides the conserved P. aeruginosa core genome. Each prophage contains a putative chitinase coding gene, and the prophage II contains a capB gene encoding a putative cold stress protein. The non-phage genomic islands contain genes responsible for pyoluteorin biosynthesis, environmental substance degradation and type I and III restriction-modification systems. Compared with other P. aeruginosa strains, the fewest number (3 of insertion sequences and the most number (3 of clustered regularly interspaced short palindromic repeats in M18 genome may contribute to the relative genome stability. Although the M18 genome is most closely related to that of P. aeruginosa strain LESB58, the strain M18 is more susceptible to several antimicrobial agents and easier to be erased in a mouse acute lung infection model than the strain LESB58. The whole M18 transcriptomic analysis indicated that 10.6% of the expressed genes are temperature-dependent, with 22 genes up-regulated at 28°C in three non-phage genomic islands and one prophage but none at 37°C. Conclusions The P. aeruginosa strain M18 has evolved its specific genomic structures and temperature dependent expression patterns to meet the requirement of its fitness and competitiveness under selective pressures imposed on the strain in rhizosphere niche.

  10. Pseudomonas aeruginosa outer membrane vesicles triggered by human mucosal fluid and lysozyme can prime host tissue surfaces for bacterial adhesion

    Directory of Open Access Journals (Sweden)

    Matteo Maria Emiliano Metruccio

    2016-06-01

    Full Text Available Pseudomonas aeruginosa is a leading cause of human morbidity and mortality that often targets epithelial surfaces. Host immunocompromise, or the presence of indwelling medical devices, including contact lenses, can predispose to infection. While medical devices are known to accumulate bacterial biofilms, it is not well understood why resistant epithelial surfaces become susceptible to P. aeruginosa. Many bacteria, including P. aeruginosa, release Outer Membrane Vesicles (OMVs in response to stress that can fuse with host cells to alter their function. Here, we tested the hypothesis that mucosal fluid can trigger OMV release to compromise an epithelial barrier. This was tested using tear fluid and corneal epithelial cells in vitro and in vivo. After 1 h both human tear fluid, and the tear component lysozyme, greatly enhanced OMV release from P. aeruginosa strain PAO1 compared to PBS controls (~100 fold. TEM and SDS-PAGE showed tear fluid and lysozyme-induced OMVs were similar in size and protein composition, but differed from biofilm-harvested OMVs, the latter smaller with fewer proteins. Lysozyme-induced OMVs were cytotoxic to human corneal epithelial cells in vitro and murine corneal epithelium in vivo. OMV exposure in vivo enhanced Ly6G/C expression at the corneal surface, suggesting myeloid cell recruitment, and primed the cornea for bacterial adhesion (~4-fold, P < 0.01. Sonication disrupted OMVs retained cytotoxic activity, but did not promote adhesion, suggesting the latter required OMV-mediated events beyond cell killing. These data suggest that mucosal fluid induced P. aeruginosa OMVs could contribute to loss of epithelial barrier function during medical device-related infections.

  11. Biodegradation of Malathion using mixed culture of Serratia marcescens BNA1and Pseudomonas aeruginosa BNA2

    Directory of Open Access Journals (Sweden)

    B Nadalian

    2016-03-01

    Full Text Available Background and Objectives: Organophosphate pesticides are used most commonly for domestic, commercial, and agricultural purposes and have been found to be highly toxic. In essence, bioremediation has become one of the most important tools for removing these compounds in the environment, considering its higher efficiency when compared with the physicochemical methods. Materials and Methods: The biodegradation efficiency of two bacterial strains (i.e. Serratia marcescens BNA1 and Pseudomonas aeruginosa BNA2 were assessed. In order to evaluate Malathion biodegradation, each sample was cultured on mineral salts medium containing Malathion as a sole carbon source. Malathion biodegradation efficiency of the strains was monitored in different culture media. The ability of bacterial isolates to degrade Malathion was studied using gas chromatography. Results: Serratia marcescens BNA1 and Pseudomonas aeruginosa BNA2 were able to degrade Malathion. Biodegradation percentage in different treatments recorded were: BNA1+Ma (33.88%, BNA2+MA (26.45%, BNA1+BNA2+Ma (46/96%, BNA1+Ma+Tween (61.05%, BNA2+Ma+Tween (40.17%, and BNA1+BNA2+Ma+ Tween (67.79%. Conclusion: It could be speculated that the best degradation efficiency can be yielded using mixture of strains plus a surfactant. The results of this study can be used in the bioremediation of Malathion contaminate soil after doing the pilot experiments.

  12. Phage ΦPan70, a Putative Temperate Phage, Controls Pseudomonas aeruginosa in Planktonic, Biofilm and Burn Mouse Model Assays

    Directory of Open Access Journals (Sweden)

    Angela V. Holguín

    2015-08-01

    Full Text Available Pseudomonas aeruginosa is one of the Multi-Drug-Resistant organisms most frequently isolated worldwide and, because of a shortage of new antibiotics, bacteriophages are considered an alternative for its treatment. Previously, P. aeruginosa phages were isolated and best candidates were chosen based on their ability to form clear plaques and their host range. This work aimed to characterize one of those phages, ΦPan70, preliminarily identified as a good candidate for phage-therapy. We performed infection curves, biofilm removal assays, transmission-electron-microscopy, pulsed-field-gel-electrophoresis, and studied the in vivo ΦPan70 biological activity in the burned mouse model. ΦPan70 was classified as a member of the Myoviridae family and, in both planktonic cells and biofilms, was responsible for a significant reduction in the bacterial population. The burned mouse model showed an animal survival between 80% and 100%, significantly different from the control animals (0%. However, analysis of the ΦPan70 genome revealed that it was 64% identical to F10, a temperate P. aeruginosa phage. Gene annotation indicated ΦPan70 as a new, but possible temperate phage, therefore not ideal for phage-therapy. Based on this, we recommend genome sequence analysis as an early step to select candidate phages for potential application in phage-therapy, before entering into a more intensive characterization.

  13. Fates of Microcystis aeruginosa Cells and Associated Microcystins in Sediment and the Effect of Coagulation Process on Them

    Directory of Open Access Journals (Sweden)

    Xiaoguo Chen

    2013-12-01

    Full Text Available During toxic Microcystis aeruginosa blooms, large amounts of cells can enter sediment through natural settlement, and coagulation treatment used to control water blooms can enhance the accumulation of cells. However, the current understanding of the fates of these cells and associated microcystins (MCs, as well as the effect of coagulation treatment on these factors, is limited. The results of the present study show that Microcystis aeruginosa cells in sediment were steadily decomposed under experimental conditions, and that they completely disappeared within 28 days. The major MCs released from settled cells were immediately degraded in sediment, and microbial degradation may be the main mechanism involved in this process. Coagulation treatment with PAC (polyaluminium chloride + sepiolite can efficiently remove Microcystis aeruginosa cells from the water column and prevent their re-invasion. Furthermore, coagulation treatment with PAC + sepiolite had no significant effect on the release and decomposition of MCs and, thus, will not enhance the MCs pollution. However, coagulation treatment can accelerate the nutrient cycle by enhancing the settlement of cells. More attention should be paid to the effect on nutrient cycle when coagulation treatment is used for restoration of aquatic ecosystems.

  14. Pseudomonas aeruginosa AlgG is a polymer level alginate C5-mannuronan epimerase.

    OpenAIRE

    Franklin, M J; Chitnis, C E; Gacesa, P; Sonesson, A; White, D. C.; Ohman, D E

    1994-01-01

    Alginate is a viscous extracellular polymer produced by mucoid strains of Pseudomonas aeruginosa that cause chronic pulmonary infections in patients with cystic fibrosis. Alginate is polymerized from GDP-mannuronate to a linear polymer of beta-1-4-linked residues of D-mannuronate and its C5-epimer, L-guluronate. We previously identified a gene called algG in the alginate biosynthetic operon that is required for incorporation of L-guluronate residues into alginate. In this study, we tested the...

  15. 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

  16. 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.

  17. Nevus Removal

    Science.gov (United States)

    ... can be fundamental to improving a patient’s overall psychosocial state. Other reasons to remove a nevus may ... This is not commonly done and presents many risks and challenges. Can’t they ... on all these same factors again. Different patients are more prone or less ...

  18. Degradation of n-Hexadecane and Its Metabolites by Pseudomonas aeruginosa under Microaerobic and Anaerobic Denitrifying Conditions

    OpenAIRE

    Chayabutra, Chawala; Ju, Lu-Kwang

    2000-01-01

    A strategy for sequential hydrocarbon bioremediation is proposed. The initial O2-requiring transformation is effected by aerobic resting cells, thus avoiding a high oxygen demand. The oxygenated metabolites can then be degraded even under anaerobic conditions when supplemented with a highly water-soluble alternative electron acceptor, such as nitrate. To develop the new strategy, some phenomena were studied by examining Pseudomonas aeruginosa fermentation. The effects of dissolved oxygen (DO)...

  19. To Hit or Not to Hit, That Is the Question - Genome-wide Structure-Based Druggability Predictions for Pseudomonas aeruginosa Proteins.

    Science.gov (United States)

    Sarkar, Aurijit; Brenk, Ruth

    2015-01-01

    Pseudomonas aeruginosa is a Gram-negative bacterium known to cause opportunistic infections in immune-compromised or immunosuppressed individuals that often prove fatal. New drugs to combat this organism are therefore sought after. To this end, we subjected the gene products of predicted perturbative genes to structure-based druggability predictions using DrugPred. Making this approach suitable for large-scale predictions required the introduction of new methods for calculation of descriptors, development of a workflow to identify suitable pockets in homologous proteins and establishment of criteria to obtain valid druggability predictions based on homologs. We were able to identify 29 perturbative proteins of P. aeruginosa that may contain druggable pockets, including some of them with no or no drug-like inhibitors deposited in ChEMBL. These proteins form promising novel targets for drug discovery against P. aeruginosa. PMID:26360059

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. Enzymes Enhance Biofilm Removal Efficiency of Cleaners.

    Science.gov (United States)

    Stiefel, Philipp; Mauerhofer, Stefan; Schneider, Jana; Maniura-Weber, Katharina; Rosenberg, Urs; Ren, Qun

    2016-06-01

    Efficient removal of biofilms from medical devices is a big challenge in health care to avoid hospital-acquired infections, especially from delicate devices like flexible endoscopes, which cannot be reprocessed using harsh chemicals or high temperatures. Therefore, milder solutions such as enzymatic cleaners have to be used, which need to be carefully developed to ensure efficacious performance. In vitro biofilm in a 96-well-plate system was used to select and optimize the formulation of novel enzymatic cleaners. Removal of the biofilm was quantified by crystal violet staining, while the disinfecting properties were evaluated by a BacTiter-Glo assay. The biofilm removal efficacy of the selected cleaner was further tested by using European standard (EN) for endoscope cleaning EN ISO 15883, and removal of artificial blood soil was investigated by treating TOSI (Test Object Surgical Instrument) cleaning indicators. Using the process described here, a novel enzymatic endoscope cleaner was developed, which removed 95% of Staphylococcus aureus and 90% of Pseudomonas aeruginosa biofilms in the 96-well plate system. With a >99% reduction of CFU and a >90% reduction of extracellular polymeric substances, this cleaner enabled subsequent complete disinfection and fulfilled acceptance criteria of EN ISO 15883. Furthermore, it efficiently removed blood soil and significantly outperformed comparable commercial products. The cleaning performance was stable even after storage of the cleaner for 6 months. It was demonstrated that incorporation of appropriate enzymes into the cleaner enhanced performance significantly. PMID:27044552

  7. 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...

  8. Enzymatic removal and disinfection of bacterial biofilms

    DEFF Research Database (Denmark)

    Johansen, Charlotte; Falholt, Per; Gram, Lone

    1997-01-01

    Model biofilms of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas fluorescens, and Pseudomonas aeruginosa were made on steel and polypropylene substrata. Plaque-resembling biofilms of Streptococcus mutans, Actinomyces, viscosus, and Fusobacterium nucleatum were made on saliva......-coated hydroxyapatite. The activity of enzymes against bacterial cells in biofilm was measured by fluorescence microscopy and an indirect conductance test in which evolution of carbon dioxide was measured. Glucose oxidase combined with lactoperoxidase was bactericidal against biofilm bacteria but did not remove the...... biofilm from the substrata. A complex mixture of polysaccharide-hydrolyzing enzymes was able to remove bacterial biofilm from steel and polypropylene substrata but did not have a significant bactericidal activity. Combining oxidoreductases with polysaccharide-hydrolyzing enzymes resulted in bactericidal...

  9. Electron transfer of Pseudomonas aeruginosa CP1 in electrochemical reduction of nitric oxide.

    Science.gov (United States)

    Zhou, Shaofeng; Huang, Shaobin; He, Jiaxin; Li, Han; Zhang, Yongqing

    2016-10-01

    This study reports catalytic electro-chemical reduction of nitric oxide (NO) enhanced by Pseudomonas aeruginosa strain CP1. The current generated in the presence of bacteria was 4.36times that in the absence of the bacteria. The strain was able to catalyze electro-chemical reduction of NO via indirect electron transfer with an electrode, revealed by a series of cyclic voltammetry experiments. Soluble electron shuttles secreted into solution by live bacteria were responsible for the catalytic effects. The enhancement of NO reduction was also confirmed by detection of nitrous oxide; the level of this intermediate was 46.4% higher in the presence of bacteria than in controls, illustrated that the electron transfer pathway did not directly reduce nitric oxide to N2. The findings of this study may offer a new model for bioelectrochemical research in the field of NO removal by biocatalysts. PMID:27426634

  10. Removal of

    OpenAIRE

    Roohan Rakhshaee; Zahra Zamiraee; Somaieh Baghipour; Mohammad Panahandeh

    2013-01-01

    Background and Objectives: Azolla Filiculoides as a non-living fern was used in a batch system to remove "Basic Blue 3", which is a cationic dye and a carcinogenic agent.Materials and Methods: We used a batch system by applying certain concentrations of dye contaminant and in the presence of a certain amount of adsorbent under optimum conditions. The main groups presenting in the Azolla cell wall were evaluated by acidification and alkalization of Azolla's media and then potentiometric titrat...

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

    LENUS (Irish Health Repository)

    Linnane, Barry

    2015-10-01

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

  12. 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

  13. Removal of

    Directory of Open Access Journals (Sweden)

    Roohan Rakhshaee

    2013-02-01

    Full Text Available Background and Objectives: Azolla Filiculoides as a non-living fern was used in a batch system to remove "Basic Blue 3", which is a cationic dye and a carcinogenic agent.Materials and Methods: We used a batch system by applying certain concentrations of dye contaminant and in the presence of a certain amount of adsorbent under optimum conditions. The main groups presenting in the Azolla cell wall were evaluated by acidification and alkalization of Azolla's media and then potentiometric titration with standard basic and acidic solutions. Results: It was observed that the removal efficiency of dye using non-living Azolla in accordance with the Langmuir isotherms was 82% for the initial dye concentration of 200 mg/lit under reaction conditions consisting of contact time 6 h, pH= 6, temperature 25 ˚C, and dose 5 g/lit. Qmax (maximum uptake capacity by the activated Azolla at three temperatures 5, 25 and 50 ˚C was 0.732, 0.934, and 1.176 mmol/g respectively. ΔG (Gibbs free energy changes was obtained for these temperatures as -0.457, -0.762, and -1.185 kJ/mol respectively.Conclusion: Removal of basic blue 3 using Azolla is an economically and effective method.

  14. 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...

  15. 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...

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. [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

  2. 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...

  3. Laser assisted graffiti paints removing

    Science.gov (United States)

    Novikov, B. Y.; Chikalev, Y. V.; Shakhno, E. A.

    2011-02-01

    It's hard to imagine a modern city view without some drawings and inscriptions, usually called "graffiti". Traditional cleaning methods do not suit modern requirements. Investigation of possibilities of laser assisted paints removing is described in this article. The conditions for removing different paints from different surfaces were defined.

  4. Ndk, a novel host-responsive regulator, negatively regulates bacterial virulence through quorum sensing in Pseudomonas aeruginosa

    Science.gov (United States)

    Yu, Hua; Xiong, Junzhi; Zhang, Rong; Hu, Xiaomei; Qiu, Jing; Zhang, Di; Xu, Xiaohui; Xin, Rong; He, Xiaomei; Xie, Wei; Sheng, Halei; Chen, Qian; Zhang, Le; Rao, Xiancai; Zhang, Kebin

    2016-01-01

    Pathogenic bacteria could adjust gene expression to enable their survival in the distinct host environment. However, the mechanism by which bacteria adapt to the host environment is not well described. In this study, we demonstrated that nucleoside diphosphate kinase (Ndk) of Pseudomonas aeruginosa is critical for adjusting the bacterial virulence determinants during infection. Ndk expression was down-regulated in the pulmonary alveoli of a mouse model of acute pneumonia. Knockout of ndk up-regulated transcription factor ExsA-mediated T3S regulon expression and decreased exoproduct-related gene expression through the inhibition of the quorum sensing hierarchy. Moreover, in vitro and in vivo studies demonstrated that the ndk mutant exhibits enhanced cytotoxicity and host pathogenicity by increasing T3SS proteins. Taken together, our data reveal that ndk is a critical novel host-responsive gene required for coordinating P. aeruginosa virulence upon acute infection. PMID:27345215

  5. Ndk, a novel host-responsive regulator, negatively regulates bacterial virulence through quorum sensing in Pseudomonas aeruginosa.

    Science.gov (United States)

    Yu, Hua; Xiong, Junzhi; Zhang, Rong; Hu, Xiaomei; Qiu, Jing; Zhang, Di; Xu, Xiaohui; Xin, Rong; He, Xiaomei; Xie, Wei; Sheng, Halei; Chen, Qian; Zhang, Le; Rao, Xiancai; Zhang, Kebin

    2016-01-01

    Pathogenic bacteria could adjust gene expression to enable their survival in the distinct host environment. However, the mechanism by which bacteria adapt to the host environment is not well described. In this study, we demonstrated that nucleoside diphosphate kinase (Ndk) of Pseudomonas aeruginosa is critical for adjusting the bacterial virulence determinants during infection. Ndk expression was down-regulated in the pulmonary alveoli of a mouse model of acute pneumonia. Knockout of ndk up-regulated transcription factor ExsA-mediated T3S regulon expression and decreased exoproduct-related gene expression through the inhibition of the quorum sensing hierarchy. Moreover, in vitro and in vivo studies demonstrated that the ndk mutant exhibits enhanced cytotoxicity and host pathogenicity by increasing T3SS proteins. Taken together, our data reveal that ndk is a critical novel host-responsive gene required for coordinating P. aeruginosa virulence upon acute infection. PMID:27345215

  6. Simultaneous Removal of Phenol and Dissolved Solids from Wastewater Using Multichambered Microbial Desalination Cell.

    Science.gov (United States)

    Pradhan, Harapriya; Jain, Sumat Chand; Ghangrekar, Makarand M

    2015-12-01

    Microbial desalination cell (MDC) has great potential toward direct electricity generation from wastewater and concurrent desalination through potential difference developed due to microbial activity. Degradation of phenol by isolate Pseudomonas aeruginosa in anodic chamber and simultaneous desalination of water in middle desalination chamber of multichamber MDC is demonstrated in this study. Performance of the MDCs with different anodic inoculum conditions, namely pure culture of P. aeruginosa (MDC-1), 50 % v/v mixture of P. aeruginosa and anaerobic mixed consortia (MDC-2) and anaerobic mixed consortia (MDC-3), was evaluated to compare the phenol degradation in anodic chamber, bioelectricity generation, and simultaneous total dissolved solids (TDS) removal from saline water in desalination chamber. Synergistic effect between P. aeruginosa and mixed anaerobic consortia as inoculum was evident in MDC-2 demonstrating phenol degradation of 90 %, TDS removal of 75 % in 72 h of reaction time along with higher power generation of 27.5 mW/m(2) as compared to MDC-1 (95 %, 64 %, 12.8 mW/m(2), respectively) and MDC-3 (58 %, 52 %, 4.8 mW/m(2), respectively). The results illustrate that the multichamber MDC-2 is effective for simultaneous removal of phenol and dissolved solids contained in industrial wastewaters. PMID:26373945

  7. 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...

  8. Synergistic effect of membrane-active peptides polymyxin B and gramicidin S on multidrug-resistant strains and biofilms of Pseudomonas aeruginosa.

    Science.gov (United States)

    Berditsch, Marina; Jäger, Thomas; Strempel, Nikola; Schwartz, Thomas; Overhage, Jörg; Ulrich, Anne S

    2015-09-01

    Multidrug-resistant Pseudomonas aeruginosa is a major cause of severe hospital-acquired infections. Currently, polymyxin B (PMB) is a last-resort antibiotic for the treatment of infections caused by Gram-negative bacteria, despite its undesirable side effects. The delivery of drug combinations has been shown to reduce the required therapeutic doses of antibacterial agents and thereby their toxicity if a synergistic effect is present. In this study, we investigated the synergy between two cyclic antimicrobial peptides, PMB and gramicidin S (GS), against different P. aeruginosa isolates, using a quantitative checkerboard assay with resazurin as a growth indicator. Among the 28 strains that we studied, 20 strains showed a distinct synergistic effect, represented by a fractional inhibitory concentration index (FICI) of ≤0.5. Remarkably, several clinical P. aeruginosa isolates that grew as small-colony variants revealed a nonsynergistic effect, as indicated by FICIs between >0.5 and ≤0.70. In addition to inhibiting the growth of planktonic bacteria, the peptide combinations significantly decreased static biofilm growth compared with treatment with the individual peptides. There was also a faster and more prolonged effect when the combination of PMB and GS was used compared with single-peptide treatments on the metabolic activity of pregrown biofilms. The results of the present study define a synergistic interaction between two cyclic membrane-active peptides toward 17 multidrug-resistant P. aeruginosa and biofilms of P. aeruginosa strain PAO1. Thus, the application of PMB and GS in combination is a promising option for a topical medication and in the prevention of acute and chronic infections caused by multidrug-resistant or biofilm-forming P. aeruginosa. PMID:26077259

  9. 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

  10. Genotypic Diversity within a Single Pseudomonas aeruginosa Strain Commonly Shared by Australian Patients with Cystic Fibrosis

    Science.gov (United States)

    Tai, Anna Sze; Bell, Scott Cameron; Kidd, Timothy James; Trembizki, Ella; Buckley, Cameron; Ramsay, Kay Annette; David, Michael; Wainwright, Claire Elizabeth; Grimwood, Keith; Whiley, David Mark

    2015-01-01

    In cystic fibrosis (CF), Pseudomonas aeruginosa undergoes intra-strain genotypic and phenotypic diversification while establishing and maintaining chronic lung infections. As the clinical significance of these changes is uncertain, we investigated intra-strain diversity in commonly shared strains from CF patients to determine if specific gene mutations were associated with increased antibiotic resistance and worse clinical outcomes. Two-hundred-and-one P. aeruginosa isolates (163 represented a dominant Australian shared strain, AUST-02) from two Queensland CF centres over two distinct time-periods (2001–2002 and 2007–2009) underwent mexZ and lasR sequencing. Broth microdilution antibiotic susceptibility testing in a subset of isolates was also performed. We identified a novel AUST-02 subtype (M3L7) in adults attending a single Queensland CF centre. This M3L7 subtype was multi-drug resistant and had significantly higher antibiotic minimum inhibitory concentrations than other AUST-02 subtypes. Prospective molecular surveillance using polymerase chain reaction assays determined the prevalence of the ‘M3L7’ subtype at this centre during 2007–2009 (170 patients) and 2011 (173 patients). Three-year clinical outcomes of patients harbouring different strains and subtypes were compared. MexZ and LasR sequences from AUST-02 isolates were more likely in 2007–2009 than 2001–2002 to exhibit mutations (mexZ: odds ratio (OR) = 3.8; 95% confidence interval (CI): 1.1–13.5 and LasR: OR = 2.5; 95%CI: 1.3–5.0). Surveillance at the adult centre in 2007–2009 identified M3L7 in 28/509 (5.5%) P. aeruginosa isolates from 13/170 (7.6%) patients. A repeat survey in 2011 identified M3L7 in 21/519 (4.0%) P. aeruginosa isolates from 11/173 (6.4%) patients. The M3L7 subtype was associated with greater intravenous antibiotic and hospitalisation requirements, and a higher 3-year risk of death/lung transplantation, than other AUST-02 subtypes (adjusted hazard ratio [HR] = 9

  11. Genotypic Diversity within a Single Pseudomonas aeruginosa Strain Commonly Shared by Australian Patients with Cystic Fibrosis.

    Science.gov (United States)

    Tai, Anna Sze; Bell, Scott Cameron; Kidd, Timothy James; Trembizki, Ella; Buckley, Cameron; Ramsay, Kay Annette; David, Michael; Wainwright, Claire Elizabeth; Grimwood, Keith; Whiley, David Mark

    2015-01-01

    In cystic fibrosis (CF), Pseudomonas aeruginosa undergoes intra-strain genotypic and phenotypic diversification while establishing and maintaining chronic lung infections. As the clinical significance of these changes is uncertain, we investigated intra-strain diversity in commonly shared strains from CF patients to determine if specific gene mutations were associated with increased antibiotic resistance and worse clinical outcomes. Two-hundred-and-one P. aeruginosa isolates (163 represented a dominant Australian shared strain, AUST-02) from two Queensland CF centres over two distinct time-periods (2001-2002 and 2007-2009) underwent mexZ and lasR sequencing. Broth microdilution antibiotic susceptibility testing in a subset of isolates was also performed. We identified a novel AUST-02 subtype (M3L7) in adults attending a single Queensland CF centre. This M3L7 subtype was multi-drug resistant and had significantly higher antibiotic minimum inhibitory concentrations than other AUST-02 subtypes. Prospective molecular surveillance using polymerase chain reaction assays determined the prevalence of the 'M3L7' subtype at this centre during 2007-2009 (170 patients) and 2011 (173 patients). Three-year clinical outcomes of patients harbouring different strains and subtypes were compared. MexZ and LasR sequences from AUST-02 isolates were more likely in 2007-2009 than 2001-2002 to exhibit mutations (mexZ: odds ratio (OR) = 3.8; 95% confidence interval (CI): 1.1-13.5 and LasR: OR = 2.5; 95%CI: 1.3-5.0). Surveillance at the adult centre in 2007-2009 identified M3L7 in 28/509 (5.5%) P. aeruginosa isolates from 13/170 (7.6%) patients. A repeat survey in 2011 identified M3L7 in 21/519 (4.0%) P. aeruginosa isolates from 11/173 (6.4%) patients. The M3L7 subtype was associated with greater intravenous antibiotic and hospitalisation requirements, and a higher 3-year risk of death/lung transplantation, than other AUST-02 subtypes (adjusted hazard ratio [HR] = 9.4; 95%CI: 2.2-39.2) and

  12. 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

  13. 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

  14. 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....

  15. 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...

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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.

  5. 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.

  6. Pantethine rescues phosphopantothenoylcysteine synthetase and phosphopantothenoylcysteine decarboxylase deficiency in Escherichia coli but not in Pseudomonas aeruginosa.

    Science.gov (United States)

    Balibar, Carl J; Hollis-Symynkywicz, Micah F; Tao, Jianshi

    2011-07-01

    Coenzyme A (CoA) plays a central and essential role in all living organisms. The pathway leading to CoA biosynthesis has been considered an attractive target for developing new antimicrobial agents with novel mechanisms of action. By using an arabinose-regulated expression system, the essentiality of coaBC, a single gene encoding a bifunctional protein catalyzing two consecutive steps in the CoA pathway converting 4'-phosphopantothenate to 4'-phosphopantetheine, was confirmed in Escherichia coli. Utilizing this regulated coaBC strain, it was further demonstrated that E. coli can effectively metabolize pantethine to bypass the requirement for coaBC. Interestingly, pantethine cannot be used by Pseudomonas aeruginosa to obviate coaBC. Through reciprocal complementation studies in combination with biochemical characterization, it was demonstrated that the differential characteristics of pantethine utilization in these two microorganisms are due to the different substrate specificities associated with endogenous pantothenate kinase, the first enzyme in the CoA biosynthetic pathway encoded by coaA in E. coli and coaX in P. aeruginosa. PMID:21551303

  7. Pseudomonas aeruginosa Transmigrates at Epithelial Cell-Cell Junctions, Exploiting Sites of Cell Division and Senescent Cell Extrusion.

    Directory of Open Access Journals (Sweden)

    Guillaume Golovkine

    2016-01-01

    Full Text Available To achieve systemic infection, bacterial pathogens must overcome the critical and challenging step of transmigration across epithelial barriers. This is particularly true for opportunistic pathogens such as Pseudomonas aeruginosa, an agent which causes nosocomial infections. Despite extensive study, details on the mechanisms used by this bacterium to transmigrate across epithelial tissues, as well as the entry sites it uses, remain speculative. Here, using real-time microscopy and a model epithelial barrier, we show that P. aeruginosa employs a paracellular transmigration route, taking advantage of altered cell-cell junctions at sites of cell division or when senescent cells are expelled from the cell layer. Once a bacterium transmigrates, it is followed by a cohort of bacteria using the same entry point. The basal compartment is then invaded radially from the initial penetration site. Effective transmigration and propagation require type 4 pili, the type 3 secretion system (T3SS and a flagellum, although flagellum-deficient bacteria can occasionally invade the basal compartment from wounded areas. In the basal compartment, the bacteria inject the T3SS toxins into host cells, disrupting the cytoskeleton and focal contacts to allow their progression under the cells. Thus, P. aeruginosa exploits intrinsic host cell processes to breach the epithelium and invade the subcellular compartment.

  8. A three-phase in-vitro system for studying Pseudomonas aeruginosa adhesion and biofilm formation upon hydrogel contact lenses

    Directory of Open Access Journals (Sweden)

    Kohlmann Thomas

    2010-11-01

    Full Text Available Abstract Background Pseudomonas aeruginosa is commonly associated with contact lens (CL -related eye infections, for which bacterial adhesion and biofilm formation upon hydrogel CLs is a specific risk factor. Whilst P. aeruginosa has been widely used as a model organism for initial biofilm formation on CLs, in-vitro models that closely reproduce in-vivo conditions have rarely been presented. Results In the current investigation, a novel in-vitro biofilm model for studying the adherence of P. aeruginosa to hydrogel CLs was established. Nutritional and interfacial conditions similar to those in the eye of a CL wearer were created through the involvement of a solid:liquid and a solid:air interface, shear forces and a complex artificial tear fluid. Bioburdens varied depending on the CL material and biofilm maturation occurred after 72 h incubation. Whilst a range of biofilm morphologies were visualised including dispersed and adherent bacterial cells, aggregates and colonies embedded in extracellular polymer substances (EPS, EPS fibres, mushroom-like formations, and crystalline structures, a compact and heterogeneous biofilm morphology predominated on all CL materials. Conclusions In order to better understand the process of biofilm formation on CLs and to test the efficacy of CL care solutions, representative in-vitro biofilm models are required. Here, we present a three-phase biofilm model that simulates the environment in the eye of a CL wearer and thus generates biofilms which resemble those commonly observed in-situ.

  9. Kinetics of cell lysis for Microcystis aeruginosa and Nitzschia palea in the exposure to β-cyclocitral

    International Nuclear Information System (INIS)

    The effect of an algal metabolite, β-cyclocitral, on the cell integrity of two cyanobacteria and one diatom was investigated. The cyanobacteria, Microcystis aeruginosa PCC 7005 and PCC 7820, and the diatom, Nitzschia palea, were exposed to various concentrations of β-cyclocitral. Scanning electron microscope (SEM) results indicate that the cells of tested species were greatly altered after being exposed to β-cyclocitral. A flow cytometer coupled with the SYTOX stain and chlorophyll-a auto-fluorescence was used to quantify the effect of β-cyclocitral on cell integrity for the tested cyanobacteria and diatom. Kinetic experiments show that about 5-10 mg L-1 of β-cyclocitral for the two M. aeruginosa strains and a much lower concentration, 0.1-0.5 mg L-1, for N. palea were needed to cause 15-20% of cells to rupture. When the β-cyclocitral concentration was increased to 200-1000 mg L-1 for M. aeruginosa and 5-10 mg L-1 for N. palea, almost all the cells ruptured between 8 and 24 h. A first-order kinetic model is able to describe the data of cell integrity over time. The extracted rate constant values well correlate with the applied β-cyclocitral dosages. The obtained kinetic parameters may be used to estimate β-cyclocitral dosage and contact time required for the control of cyanobacteria and diatoms in water bodies.

  10. Assessment of the Effects of Light Availability on Growth and Competition Between Strains of Planktothrix agardhii and Microcystis aeruginosa.

    Science.gov (United States)

    Torres, Camila de Araujo; Lürling, Miquel; Marinho, Marcelo Manzi

    2016-05-01

    In this study, we tested the hypothesis that Planktothrix agardhii strains isolated from a tropical water body were better competitors for light than Microcystis aeruginosa strains. These cyanobacteria are common in eutrophic systems, where light is one of the main drivers of phytoplankton, and Planktothrix is considered more shade-adapted and Microcystis more high-light tolerant. First, the effect of light intensities on growth was studied in batch cultures. Next, the minimum requirement of light (I*) and the effect of light limitation on the outcome of competition was investigated in chemostats. All strains showed similar growth at 10 μmol photons m(-2) s(-1), demonstrating the ability of the two species to grow in low light. The optimum light intensity was lower for P. agardhii, but at the highest light intensity, Microcystis strains reached higher biovolume, confirming that P. agardhii has higher sensitivity to high light. Nonetheless, P. agardhii grew in light intensities considered high (500 μmol photons m(-2) s(-1)) for this species. M. aeruginosa showed a higher carrying capacity in light-limited condition, but I* was similar between all the strains. Under light competition, Microcystis strains displaced P. agardhii and dominated. In two cases, there was competitive exclusion and in the other two P. agardhii managed to remain in the system with a low biovolume (≈15 %). Our findings not only show that strains of P. agardhii can grow under higher light intensities than generally assumed but also that strains of M. aeruginosa are better competitors for light than supposed. These results help to understand the co-occurrence of these species in tropical environments and the dominance of M. aeruginosa even in low-light conditions. PMID:26691315

  11. Pseudomonas aeruginosa Cystic Fibrosis isolates of similar RAPD genotype exhibit diversity in biofilm forming ability in vitro

    Directory of Open Access Journals (Sweden)

    Elborn Stuart J

    2010-02-01

    Full Text Available Abstract Background Pseudomonas aeruginosa is considered to grow in a biofilm in cystic fibrosis (CF chronic lung infections. Bacterial cell motility is one of the main factors that have been connected with P. aeruginosa adherence to both biotic and abiotic surfaces. In this investigation, we employed molecular and microscopic methods to determine the presence or absence of motility in P. aeruginosa CF isolates, and statistically correlated this with their biofilm forming ability in vitro. Results Our investigations revealed a wide diversity in the production, architecture and control of biofilm formation. Of 96 isolates, 49% possessed swimming motility, 27% twitching and 52% swarming motility, while 47% were non-motile. Microtitre plate assays for biofilm formation showed a range of biofilm formation ability from biofilm deficient phenotypes to those that formed very thick biofilms. A comparison of the motility and adherence properties of individual strains demonstrated that the presence of swimming and twitching motility positively affected biofilm biomass. Crucially, however, motility was not an absolute requirement for biofilm formation, as 30 non-motile isolates actually formed thick biofilms, and three motile isolates that had both flagella and type IV pili attached only weakly. In addition, CLSM analysis showed that biofilm-forming strains of P. aeruginosa were in fact capable of entrapping non-biofilm forming strains, such that these 'non-biofilm forming' cells could be observed as part of the mature biofilm architecture. Conclusions Clinical isolates that do not produce biofilms in the laboratory must have the ability to survive in the patient lung. We propose that a synergy exists between isolates in vivo, which allows "non biofilm-forming" isolates to be incorporated into the biofilm. Therefore, there is the potential for strains that are apparently non-biofilm forming in vitro to participate in biofilm-mediated pathogenesis in the CF

  12. 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.

  13. Dissection of the cis-2-decenoic acid signaling network in Pseudomonas aeruginosa using microarray technique

    Directory of Open Access Journals (Sweden)

    Azadeh eRahmani-Badi

    2015-04-01

    Full Text Available Many bacterial pathogens use quorum-sensing (QS signaling to regulate the expression of factors contributing to virulence and persistence. Bacteria produce signals of different chemical classes. The signal molecule, known as diffusible signal factor (DSF, is a cis-unsaturated fatty acid that was first described in the plant pathogen Xanthomonas campestris. Previous works have shown that human pathogen, Pseudomonas aeruginosa, also synthesizes a structurally related molecule, characterized as cis-2-decenoic acid (C10: Δ2, CDA that induces biofilm dispersal by multiple types of bacteria. Furthermore, CDA has been shown to be involved in inter-kingdom signaling that modulates fungal behavior. Therefore, an understanding of its signaling mechanism could suggest strategies for interference, with consequences for disease control. To identify the components of CDA signaling pathway in this pathogen, a comparative transcritpome analysis was conducted, in the presence and absence of CDA. A protein-protein interaction (PPI network for differentially expressed (DE genes with known function was then constructed by STRING and Cytoscape. In addition, the effects of CDA in combination with antimicrobial agents on the biofilm surface area and bacteria viability were evaluated using fluorescence microscopy and digital image analysis. Microarray analysis identified 666 differentially expressed genes in the presence of CDA and gene ontology (GO analysis revealed that in P. aeruginosa, CDA mediates dispersion of biofilms through signaling pathways, including enhanced motility, virulence as well as persistence at different temperatures. PPI data suggested that a cluster of five genes (PA4978, PA4979, PA4980, PA4982, PA4983 is involved in the CDA synthesis and perception. Combined treatments using both CDA and antimicrobial agents showed that following exposure of the biofilms to CDA, remaining cells on the surface were easily removed and killed by antimicrobials.

  14. 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...

  15. 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

  16. 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...

  17. 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.

  18. 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

  19. 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

  20. 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...

  1. 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...

  2. 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...

  3. 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 (...

  4. 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...

  5. 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.

  6. [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

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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

  13. 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...

  14. 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...

  15. 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 ...

  16. 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...

  17. 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.

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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....

  3. 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...

  4. 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 ...

  5. 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...

  6. 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

  7. 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...

  8. 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

  9. 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...

  10. 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. ...

  11. 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...

  12. 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...

  13. 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

  14. 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.

  15. 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

  16. 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.

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

    LENUS (Irish Health Repository)

    Guyot, Nicolas

    2010-06-01

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

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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...

  3. 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...

  4. UVC fluencies for preventative treatment of Pseudomonas aeruginosa contaminated polymer tubes

    DEFF Research Database (Denmark)

    Bak, Jimmy; Ladefoged, Søren D; Begovic, Tanja;

    2010-01-01

    Exposing Pseudomonas aeruginosa biofilm grown on the inner surface of Teflon and silicone tubes to UVC light (265 nm) from light emitting diodes (LED) has previously been shown to substantially reduce biofilm growth. Smaller UVC fluencies were required to disinfect Teflon tubes compared to silicone...... tubes. Light propagation enhancement in tubes can be obtained if the refractive index of the intra-luminal saline solution is higher than that of the polymer. This condition is achieved by using Teflon tubes with a low refractive index (1.34) instead of the polymers with a high refractive index (1...... demonstrated to be a preventative disinfection treatment on tubes made of Teflon, which enhances the UVC light propagation, and on tubes made of a softer material, ethylene vinyl acetate (EVA), which is suitable for catheters but much less suitable for UVC light propagation. Simulating an aseptic breach (~10...

  5. The Pseudomonas aeruginosa autoinducer dodecanoyl-homoserine lactone inhibits the putrescine synthesis in human cells

    DEFF Research Database (Denmark)

    Kristiansen, S.; Bjarnsholt, Thomas; Adeltoft, D.;

    2008-01-01

    Pseudomonas aeruginosa uses acyl-homoserine lactones to coordinate gene transcription in a process called quorum sensing (QS). The QS molecules C-4-HSL and C-12-oxo-HSL are synthesized from the universal precursor S-adenosyl methionine, which is also a precursor of polyamines in human cells....... Polyamines are required for mitotic cell division and peak during this phase. The polyamine putrescine is synthesized by ornithine decarboxylase (ODC) as a rate-limiting step. The ODC enzyme concentration also peaks during the mitotic phase. This peak is mediated by translation of ODC mRNA by the ITAF45...... protein, which translocates from the nuclear compartment to the cytoplasm in a phosphorylation-dependent manner. We observed that C-12-HSL-treated human epidermal cells had a higher cytoplasm-to-nuclear ITAF45 protein concentration and this translocation was dependent on the dephosphorylation of ITAF45...

  6. 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...

  7. 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

  8. Pseudomonas aeruginosa Biofilm Response and Resistance to Cold Atmospheric Pressure Plasma Is Linked to the Redox-Active Molecule Phenazine.

    Directory of Open Access Journals (Sweden)

    Anne Mai-Prochnow

    Full Text Available Pseudomonas aeruginosa is an important opportunistic pathogen displaying high antibiotic resistance. Its resistance is in part due to its outstanding ability to form biofilms on a range of biotic and abiotic surfaces leading to difficult-to-treat, often long-term infections. Cold atmospheric plasma (CAP is a new, promising antibacterial treatment to combat antibiotic-resistant bacteria. Plasma is ionized gas that has antibacterial properties through the generation of a mix of reactive oxygen and nitrogen species (RONS, excited molecules, charged particles and UV photons. Our results show the efficient removal of P. aeruginosa biofilms using a plasma jet (kINPen med, with no viable cells detected after 5 min treatment and no attached biofilm cells visible with confocal microscopy after 10 min plasma treatment. Because of its multi-factorial action, it is widely presumed that the development of bacterial resistance to plasma is unlikely. However, our results indicate that a short plasma treatment (3 min may lead to the emergence of a small number of surviving cells exhibiting enhanced resistance to subsequent plasma exposure. Interestingly, these cells also exhibited a higher degree of resistance to hydrogen peroxide. Whole genome comparison between surviving cells and control cells revealed 10 distinct polymorphic regions, including four belonging to the redox active, antibiotic pigment phenazine. Subsequently, the interaction between phenazine production and CAP resistance was demonstrated in biofilms of transposon mutants disrupted in different phenazine pathway genes which exhibited significantly altered sensitivity to CAP.

  9. Capture of endogenously biotinylated proteins from Pseudomonas aeruginosa displays unexpected downregulation of LiuD upon iron nutrition.

    Science.gov (United States)

    Kaschani, Farnusch; Wei, Qing; Dingemans, Jozef; van der Hoorn, Renier A L; Cornelis, Pierre; Kaiser, Markus

    2016-08-01

    The uptake and storage but also removal of excess iron are of utmost importance to microorganisms since surplus levels of iron may lead to the formation of reactive oxygen species. Therefore, iron homeostasis is generally tightly regulated by the ferric uptake regulator (Fur), a global iron regulator acting as a transcriptional repressor. While detecting biotinylated proteins in labelling experiments, we discovered that the endogenously biotinylated protein LiuD differentially accumulated upon iron treatment. LiuD represents the α-subunit of the methylcrotonyl-CoA-carboxylase (MCCase), an enzyme from the leucine/isovalerate utilization pathway. Real-time PCR transcription analysis revealed that the observed lower levels of LiuD biotinylation could be traced back to lower LiuD protein levels via a transcriptional repression of liuABCDE expression that however does not seem to be mediated by Fur. In accordance with LiuD's role for the leucine/isovalerate utilization pathway and its protein level regulation by nutritional iron levels, we found that wild-type Pseudomonas aeruginosa did not grow in the presence of iron if the medium contained only leucine as a carbon source. Conversely, iron stimulated the growth when glucose was used as a carbon source. Our study thus demonstrates the complexities of iron-regulated bacterial growth in Pseudomonas aeruginosa. PMID:27160053

  10. Pseudomonas aeruginosa infection in embryonated hen's eggs. An alternative in vivo model for the screening of antibacterial substances.

    Science.gov (United States)

    Härtl, A; Möllmann, U; Schrinner, E; Stelzner, A

    1997-09-01

    Embryonated hens' eggs can be reliably infected by Pseudomonas aeruginosa in laboratory experiments. Therapy tests with the antibiotics azlocillin (CAS 37091-66-0) and gentamicin (CAS 13291-74-2) on this type of infected hens' eggs demonstrate that this test system offers a realistic alternative to septic experiments with small laboratory rodents. Chick embryos survive a lethal Pseudomonas infection when azlocillin or gentamicin in a relevant therapeutic dose are administered immediately after the infective agent. The use of Pseudomonas infected chick embryos in the screening for new antiinfectives allows, therefore, a considerable reduction of the number of laboratory rodents required. PMID:9342424

  11. Simple sequence repeats and mucoid conversion: biased mucA mutagenesis in mismatch repair-deficient Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Alejandro J Moyano

    Full Text Available In Pseudomonas aeruginosa, conversion to the mucoid phenotype marks the onset of an irreversible state of the infection in Cystic Fibrosis (CF patients. The main pathway for mucoid conversion is mutagenesis of the mucA gene, frequently due to -1 bp deletions in a simple sequence repeat (SSR of 5 Gs (G(5-SSR(426. We have recently observed that this mucA mutation is particularly accentuated in Mismatch Repair System (MRS-deficient cells grown in vitro. Interestingly, previous reports have shown a high prevalence of hypermutable MRS-deficient strains occurring naturally in CF chronic lung infections. Here, we used mucA as a forward mutation model to systematically evaluate the role of G(5-SSR(426 in conversion to mucoidy in a MRS-deficient background, with this being the first analysis combining SSR-dependent localized hypermutability and the acquisition of a particular virulence/persistence trait in P. aeruginosa. In this study, mucA alleles were engineered with different contents of G:C SSRs, and tested for their effect on the mucoid conversion frequency and mucA mutational spectra in a mutS-deficient strain of P. aeruginosa. Importantly, deletion of G(5-SSR(426 severely reduced the emergence frequency of mucoid variants, with no preferential site of mutagenesis within mucA. Moreover, although mutagenesis in mucA was not totally removed, this was no longer the main pathway for mucoid conversion, suggesting that G(5-SSR(426 biased mutations towards mucA. Mutagenesis in mucA was restored by the addition of a new SSR (C(6-SSR(431, and even synergistically increased when G(5-SSR(426 and C(6-SSR(431 were present simultaneously, with the mucA mutations being restricted to -1 bp deletions within any of both G:C SSRs. These results confirm a critical role for G(5-SSR(426 enhancing the mutagenic process of mucA in MRS-deficient cells, and shed light on another mechanism, the SSR- localized hypermutability, contributing to mucoid conversion in P

  12. Pharmacodynamics of the Antibacterial Effect of and Emergence of Resistance to Doripenem in Pseudomonas aeruginosa and Acinetobacter baumannii in an In Vitro Pharmacokinetic Model

    OpenAIRE

    Bowker, Karen E.; Noel, Alan R.; Tomaselli, Sharon G.; Elliott, Heather; MacGowan, Alasdair P.

    2012-01-01

    An in vitro dilutional pharmacokinetic model of infection was used to study the pharmacodynamics of doripenem in terms of the ability to kill Pseudomonas aeruginosa or Acinetobacter baumannii and also changes in their population profiles. In dose-ranging studies, the cumulative percentages of a 24-h period that the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions (TMICs) required for doripenem to produce a 24-h bacteriostatic effect and a −2-log-unit reduction ...

  13. An usual approach to treatment of a case of multidrug resistance Pseudomonas aeruginosa peritonitis: parenteral and intraperitoneal aminoglycosides and parenteral colistin

    OpenAIRE

    Ian May; Maha Abu-Khdeir; Roland Alexander Blackwood

    2012-01-01

    Infections caused by Pseudomonas aeruginosa are becoming more common and increasingly more difficult to treat due to the continued development of drug resistance. While sensitivity to colistin (polymyxin E) is well known, it is frequently avoided due to concerns of nephrotoxicity. Reported here is a case of a multi-drug resistance pseudomonal typhlitis, bacteremia and pleural cavity infection that required significant intensive care, and serial abdominal washouts. Intra-peritoneal tobramycin ...

  14. 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...

  15. Removing Hair Safely

    Science.gov (United States)

    ... For Consumers Home For Consumers Consumer Updates Removing Hair Safely Share Tweet Linkedin Pin it More sharing ... methods of hair removal. back to top Laser Hair Removal In this method, a laser destroys hair ...

  16. Superfund TIO videos. Set A. Removal process: Planning and initiating removals, managing removals, non-CERCLA funded removals. Part 3 Audio-Visual

    International Nuclear Information System (INIS)

    The videotape is divided into three sections. Section 1 outlines the major components of planning and initiating a removal, such as identifying appropriate response actions, preparing an Action Memorandum (AM), projecting the cost of the removal, obtaining site access, setting up a command post, and overseeing the development of the required plans. The resources available to the OSC to conduct a removal also are discussed. Section 2 discusses the OSC's role in managing the removal and describes how to obtain resources and how to manage site activities and monitor costs. The statutory limits of a removal and the importance of documenting site activities accurately and completely also are outlined. Section 3 outlines the OSC's role in removal actions conducted by parties other than EPA OSCs. Discussed are CERCLA removals conducted by PRPs, States, Federal facilities and Indian tribes. Underground Storage Tank (UST) assessment and removal under Resource Conservation and Recovery Act (RCRA) authority is also discussed

  17. 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 ...

  18. 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...

  19. 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...

  20. Removal of root filling materials.

    LENUS (Irish Health Repository)

    Duncan, H.F. Chong, B.S.

    2011-05-01

    Safe, successful and effective removal of root filling materials is an integral component of non-surgical root canal re-treatment. Access to the root canal system must be achieved in order to negotiate to the canal terminus so that deficiencies in the original treatment can be rectified. Since a range of materials have been advocated for filling root canals, different techniques are required for their removal. The management of commonly encountered root filling materials during non-surgical re-treatment, including the clinical procedures necessary for removal and the associated risks, are reviewed. As gutta-percha is the most widely used and accepted root filling material, there is a greater emphasis on its removal in this review.

  1. Pseudomonas aeruginosa KUCd1, a possible candidate for cadmium bioremediation Pseudomonas aeruginosa KUCd1, um possível candidato para biorremediação de cádmio

    Directory of Open Access Journals (Sweden)

    Sangram Sinha

    2009-09-01

    Full Text Available A cadmium (8 mM resistant Pseudomonas aeruginosa strain KUCd1 exhibiting high Cd accumulation under in vitro aerobic condition has been reported. The isolate showed a significant ability to remove more than 75% and 89% of the soluble cadmium during the active growth phase from the growth medium and from Cd-amended industrial wastewater under growth supportive condition. Transmission electron microscopy (TEM and energy dispersive X-ray spectroscopy (EDXS suggest the presence of Cd in the cells from mid-stationary phase. The cell fractionation study revealed membrane and periplasm to be the major accumulating site in this strain. The chemical nature of the accumulated Cd was studied by X-ray powder diffraction analysis.Descreve-se a cepa Pseudomonas aeruginosa KUCd1 resistente a cádmio (8mM que apresenta elevado acumulo de cádmio em condições de aerobiose in vitro. Durante a fase ativa de multiplicação, a cepa apresentou capacidade de remover mais de 75% e 89% de cádmio solúvel do meio de cultura e da água residual industrial contendo Cd. A microscopia eletrônica de transmissão (TEM e espectroscopia de raio X energia dispersiva indicaram a presença de Cd nas células na fase estacionária intermediária. O fracionamento celular indicou serem a membrana e o periplasma os pontos de maior acúmulo. A natureza química do Cd acumulado foi avaliada através de análise de difração de Raios X.

  2. 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...

  3. 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...

  4. 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...

  5. 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...

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  7. 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...

  8. 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.

  9. 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...

  10. 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....

  11. 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.

  12. 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

  13. 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...

  14. 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...

  15. 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.

  16. 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...

  17. 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.

  18. 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.

  19. 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...

  20. 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.

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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

  6. 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.

  7. 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...

  8. 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

  9. 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

  10. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-01

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

  12. FimL regulates cAMP synthesis in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Yuki F Inclan

    Full Text Available Pseudomonas aeruginosa, a ubiquitous bacteria found in diverse ecological niches, is an important cause of acute infections in immunocompromised individuals and chronic infections in patients with Cystic Fibrosis. One signaling molecule required for the coordinate regulation of virulence factors associated with acute infections is 3', 5'-cyclic adenosine monophosphate, (cAMP, which binds to and activates a catabolite repressor homolog, Vfr. Vfr controls the transcription of many virulence factors, including those associated with Type IV pili (TFP, the Type III secretion system (T3SS, the Type II secretion system, flagellar-mediated motility, and quorum sensing systems. We previously identified FimL, a protein with histidine phosphotransfer-like domains, as a regulator of Vfr-dependent processes, including TFP-dependent motility and T3SS function. In this study, we carried out genetic and physiologic studies to further define the mechanism of action of FimL. Through a genetic screen designed to identify suppressors of FimL, we found a putative cAMP-specific phosphodiesterase (CpdA, suggesting that FimL regulates cAMP levels. Inactivation of CpdA increases cAMP levels and restores TFP-dependent motility and T3SS function to fimL mutants, consistent with in vivo phosphodiesterase activity. By constructing combinations of double and triple mutants in the two adenylate cyclase genes (cyaA and cyaB, fimL, and cpdA, we show that ΔfimL mutants resemble ΔcyaB mutants in TM defects, decreased T3SS transcription, and decreased cAMP levels. Similar to some of the virulence factors that they regulate, we demonstrate that CyaB and FimL are polarly localized. These results reveal new complexities in the regulation of diverse virulence pathways associated with acute P. aeruginosa infections.

  13. Pseudomonas aeruginosa C5-mannuronan epimerase: steady-state kinetics and characterization of the product.

    Science.gov (United States)

    Jerga, Agoston; Raychaudhuri, Aniruddha; Tipton, Peter A

    2006-01-17

    Alginate is a major constituent of mature biofilms produced by Pseudomonas aeruginosa. The penultimate step in the biosynthesis of alginate is the conversion of some beta-D-mannuronate residues in the polymeric substrate polymannuronan to alpha-L-guluronate residues in a reaction catalyzed by C5-mannuronan epimerase. Specificity studies conducted with size-fractionated oligomannuronates revealed that the minimal substrate contained nine monosaccharide residues. The maximum velocity of the reaction increased from 0.0018 to 0.0218 s(-1) as the substrate size increased from 10 to 20 residues, and no additional increase in kcat was observed for substrates up to 100 residues in length. The Km decreased from 80 microM for a substrate containing fewer than 15 residues to 4 microM for a substrate containing more than 100 residues. In contrast to C5-mannuronan epimerases that have been characterized in other bacterial species, P. aeruginosa C5-mannuronan epimerase does not require Ca2+ for activity, and the Ca2+-alginate complex is not a substrate for the enzyme. Analysis of the purified, active enzyme by inductively coupled plasma-emission spectroscopy revealed that no metals were present in the protein. The pH dependence of the kinetic parameters revealed that three residues on the enzyme which all have a pKa of approximately 7.6 must be protonated for catalysis to occur. The composition of the polymeric product of the epimerase reaction was analyzed by 1H NMR spectroscopy, which revealed that tracts of adjacent guluronate residues were readily formed. The reaction reached an apparent equilibrium when the guluronate composition of the polymer was 75%. PMID:16401084

  14. Pseudomonas aeruginosa C5-Mannuronan Epimerase: Steady-State Kinetics and Characterization of the Product†

    Science.gov (United States)

    Jerga, Agoston; Raychaudhuri, Aniruddha; Tipton, Peter A.

    2008-01-01

    Alginate is a major constituent of mature biofilms produced by Pseudomonas aeruginosa. The penultimate step in the biosynthesis of alginate is the conversion of some β-D-mannuronate residues in the polymeric substrate polymannuronan to α-L-guluronate residues in a reaction catalyzed by C5-mannuronan epimerase. Specificity studies conducted with size-fractionated oligomannuronates revealed that the minimal substrate contained 9 monosaccharide residues. The maximum velocity of the reaction increased from 0.0018 s−1 to 0.0218 s−1 as the substrate size increased from 10 to 20 residues, and no additional increase in kcat was observed for substrates up to 100 residues in length. The Km decreased from 80 μM for substrate containing fewer than 15 residues to 4 μM for substrate containing over 100 residues. In contrast to C5-mannuronan epimerases that have been characterized in other bacterial species, P. aeruginosa C5-mannuronan epimerase does not require Ca2+ for activity, and the Ca2+-alginate complex is not a substrate for the enzyme. Analysis of purified, active enzyme by inductively coupled plasma-emission spectroscopy revealed that no metals were present in the protein. The pH dependence of the kinetic parameters revealed that 3 residues on the enzyme which all have a pKa of about 7.6 must be protonated for catalysis to occur. The composition of the polymeric product of the epimerase reaction was analyzed by 1H-NMR spectroscopy, which revealed that tracts of adjacent guluronate residues were readily formed. The reaction reached an apparent equilibrium when the guluronate composition of the polymer was 75%. PMID:16401084

  15. In vitro assessment of antibacterial effect of garlic (allium sativum) extracts on pseudomonas aeruginosa.

    Science.gov (United States)

    Saha, S K; Saha, S; Hossain, M A; Paul, S K

    2015-04-01

    The study was aimed to determine the antibacterial effect of crude and aqueous extract of garlic (Allium stivum) against standard strain of Pseudomonas aeruginosa ATCC 27853. An interventional study was conducted in Department of Pharmacology and Therapeutics in collaboration with Department of Microbiology, Mymensingh Medical College, Mymensingh. The minimum inhibitory concentration (MIC) of aqueous garlic extract (AGE) and antibiotic Imipenem were also determined with the help of broth dilution method. Inhibitory effect of crude garlic extract (CGE) was determined by inoculation of bacteria in CGE incorporated nutrient agar (NA) media and for AGE antibacterial effect was determined by disc diffusion method. All experiments except disc diffusion procedure were reconfirmed by subculture in pure NA media. In case of CGE the growth inhibition of test organism was observed in 30% CGE incorporated NA media. On the other hand sensitivity of AGE also determined in disc diffusion and the zone of inhibition (ZOI) was 7 mm, 12 mm and 20 mm at 25 μg/10 μl, 50 μg/10 μl and 100 μg/10 μl concentrations respectively. The MICs of AGE and Imipenem were 600 μg/ml and 1μg/ml. The MIC of imipenen was far less in comparison with the MIC of AGE. From the findings it is clearly determined that both the extracts have definite antibacterial effect upon Pseudomonas aeruginosa. Further studies are required to detect and isolate the active ingredients present in the Garlic extract responsible for antibacterial effect. Then their effects against the studied organism should be studied in vivo separately and its toxicity profile should also be taken into account. Only then the Garlic extracts fulfilled the criteria for its therapeutic use. Still then external application advised for burn and superficial skin infections and may be used in food poisoning, and respiratory tract infection along with conventional antibiotics which are used in those conditions. PMID:26007246

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

    International Nuclear Information System (INIS)

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

  17. 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.

  18. 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.

  19. 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.

  20. 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...

  1. 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...

  2. 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.

  3. [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

  4. 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

  5. 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...

  6. 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.

  7. 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...

  8. 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...

  9. 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...

  10. 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)

  11. 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...

  12. 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...

  13. Uranium biomineralization by a metal resistant Pseudomonas aeruginosa strain isolated from contaminated mine waste

    International Nuclear Information System (INIS)

    Uranium biomineralization by a metal-resistant Pseudomonas aeruginosa strain isolated from uranium mine waste was characterized for its potential in bioremediation. Uranium resistance, its cellular localization and chemical nature of uranium-bacteria interaction were elucidated. Survival and uranium biomineralization from mine water were investigated using microcosm experiments. The selected bacterium showed U resistance and accumulation (maximum of 275 mg U g-1 cell dry wt.) following incubation in 100 mg U L-1, pH 4.0, for 6 h. Transmission electron microscopy and X-ray diffraction analyses revealed that bioaccumulated uranium was deposited within the cell envelope as needle shaped U-phosphate compounds that attain crystallinity only at pH 4.0. A synergistic involvement of deprotonated phosphate and carboxyl moieties in facilitating bioprecipitation of uranium was evident from FTIR analysis. Based on these findings we attribute the localized U sequestration by this bacterium as innocuous complex to its possible mechanism of uranium resistance. Microcosm data confirmed that the strain can remove soluble uranium (99%) and sequester it as U oxide and phosphate minerals while maintaining its viability. The study showed that indigenous bacteria from contaminated site that can survive uranium and other heavy metal toxicity and sequester soluble uranium as biominerals could play important role in uranium bioremediation.

  14. 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.

  15. 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....

  16. Scale up production of Protease using Pseudomonas aeruginosa MCM B-327 and its Detergent Compatibility

    Directory of Open Access Journals (Sweden)

    Vasudeo P Zambare

    2014-01-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 The maximum protease activity was obtained from P. aeruginosa MCM B-327 with soybean meal 1%, tryptone 1%, initial medium pH 7, agitation rate 250 rpm, aeration rate 0.75 vvm and fermentation temperature 30 °C, under submerged fermentation conditions (SmF. The protease productivity at 10 and 120L fermenters was found to be 16,021 and 9,975 UL-1h-1 respectively. Kinetics of cell growth revealed that specific cell growth rate was 0.025 h-1. Protease was active and stable at different pH, temperatures, in anionic, cationic and non-ionic detergent additives, as well as in commercial detergents. The protease exhibited blood stains removing performance indicating its potential in detergent industry. The dried ammonium sulphate precipitated protease was stable at room temperature for a period of one year. The Protease has shown properties suitable for its application in detergents. The results contribute to basic knowledge and application of protease from P.aeruginosa to detergent industry. The studies will help to optimize the production of this protease for biotechnological applications. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  17. 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.

  18. 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).

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. Extracellular DNA-induced antimicrobial peptide resistance mechanisms in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    ShawnLewenza

    2013-02-01

    Full Text Available Extracellular DNA (eDNA is in the environment, bodily fluids, in the matrix of biofilms, and accumulates at infection sites. Extracellular DNA can function as a nutrient source, a universal biofilm matrix component and an innate immune effector in extracellular DNA traps. In biofilms, eDNA is required for attachment, aggregation and stabilization of microcolonies. We have recently shown that eDNA can sequester divalent metal cations, which has interesting implications on antibiotic resistance. Extracellular DNA binds metal cations and thus activates the Mg2+-responsive PhoPQ and PmrAB two-component systems. In Pseudomonas aeruginosa and many other Gram-negative bacteria, the PhoPQ/PmrAB systems control various genes required for virulence and resisting killing by antimicrobial peptides, including the pmr genes (PA3552-PA3559 that are responsible for the addition of aminoarabinose to lipid A. The PA4773-PA4775 genes are a second DNA-induced cluster and are required for the production of spermidine on the outer surface, which protects the outer membrane from antimicrobial peptide treatment. Both modifications mask the negative surface charges and limit membrane damage by antimicrobial peptides. DNA-enriched biofilms or planktonic cultures have increased antibiotic resistance phenotypes to antimicrobial peptides and aminoglycosides. These dual antibiotic resistance and immune evasion strategies may be expressed in DNA-rich environments and contribute to long-term survival.

  5. 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.

  6. SENSITIVITY TO ANTIBIOTICS, ANTISEPTICAL NOSOCOMIAL PSEUDOMONAS AERUGINOSA, ISOLATED IN UROLOGICAL PATIENTS

    Directory of Open Access Journals (Sweden)

    Rymsha E.V.

    2015-05-01

    Full Text Available Introduction. Given the active introduction into clinical practice of new groups of antibiotics and antiseptics, the problem of treatment of purulent-inflammatory complications after prostatectomy and today is relevant. Of particular concern belated cases of diagnosis and treatment of postoperative complications in urological practice patients receiving antibiotic therapy The use of traditional antibiotics is not prevents the development of infection, because the problem of resistance of microorganisms to antibiotics and antiseptics remains relevant. The solution to the problem of development of infectious complications and prevent the formation of resistant clinical strains largely depends on the isolated pathogen, susceptibility to antimicrobial agents based on its bioavailability , ability to spread and penetrate into cells and tissues, selection of dose, interval, and route of administration to maintain minimum bactericidal concentration Material and methods. The study involved 145 patients who were treated in the urology Department of the Vinnytsia regional clinical hospital named of M. I. Pirogov. Patients underwent the surgical treatment of benign hypertrophic prostate. Material for bacteriological studies of purulent-inflammatory diseases were urine, pieces of the prostate, remote operationally, urinary catheters, through which conducted irrigation of the bladder. Specimen collection, transportation was carried out in accordance with modern requirements. Identification was done by morphological, cultural and biochemical properties. The definition of antibiotic resistance were performed according to "guidelines for the definition of sensitivity of microorganisms to antibiotics by the method of diffusion in agar using discs" (No. 2675-83, Kiev, 2007 12 .]. Evaluation of the results of determining the sensitivity of microorganisms to antibiotics was carried out on the basis of the determination of the zone of growth (mm of the studied

  7. 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

  8. 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

  9. 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.

  10. 8 CFR 216.2 - Notification requirements.

    Science.gov (United States)

    2010-01-01

    ... requirement that the alien and the petitioning spouse or alien entrepreneur must file a petition to remove the... petitioning spouse, or alien entrepreneur of the requirement to file a petition to remove conditions...

  11. Oral biofilm models for mechanical plaque removal

    NARCIS (Netherlands)

    Verkaik, Martinus J.; Busscher, Henk J.; Rustema-Abbing, Minie; Slomp, Anje M.; Abbas, Frank; van der Mei, Henny C.

    2010-01-01

    In vitro plaque removal studies require biofilm models that resemble in vivo dental plaque. Here, we compare contact and non-contact removal of single and dual-species biofilms as well as of biofilms grown from human whole saliva in vitro using different biofilm models. Bacteria were adhered to a sa

  12. 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 ...

  13. 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) ...

  14. 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

  15. 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

  16. Assessment of Pseudomonas aeruginosa N5,N10-methylenetetrahydrofolate dehydrogenase-cyclohydrolase as a potential antibacterial drug target.

    Directory of Open Access Journals (Sweden)

    Thomas C Eadsforth

    Full Text Available The bifunctional enzyme methylenetetrahydrofolate dehydrogenase - cyclohydrolase (FolD is identified as a potential drug target in Gram-negative bacteria, in particular the troublesome Pseudomonas aeruginosa. In order to provide a comprehensive and realistic assessment of the potential of this target for drug discovery we generated a highly efficient recombinant protein production system and purification protocol, characterized the enzyme, carried out screening of two commercial compound libraries by differential scanning fluorimetry, developed a high-throughput enzyme assay and prosecuted a screening campaign against almost 80,000 compounds. The crystal structure of P. aeruginosa FolD was determined at 2.2 Å resolution and provided a template for an assessment of druggability and for modelling of ligand complexes as well as for comparisons with the human enzyme. New FolD inhibitors were identified and characterized but the weak levels of enzyme inhibition suggest that these compounds are not optimal starting points for future development. Furthermore, the close similarity of the bacterial and human enzyme structures suggest that selective inhibition might be difficult to attain. In conclusion, although the preliminary biological data indicates that FolD represents a valuable target for the development of new antibacterial drugs, indeed spurred us to investigate it, our screening results and structural data suggest that this would be a difficult enzyme to target with respect to developing the appropriate lead molecules required to underpin a serious drug discovery effort.

  17. Mobilization and co-transport of pyrene in the presence of Pseudomonas aeruginosa UG2 biosurfactants in sandy soil columns

    Energy Technology Data Exchange (ETDEWEB)

    Lafrance, P.; Lapointe, M.

    1998-12-31

    Washing technologies are currently applied for the remediation of contaminated soils. The efficiency of biosurfactants produced by Pseudomonas aeruginosa strains to mobilize some hydrocarbons sorbed on soils has already been demonstrated. However, few studies have been made to define optimal procedures for the injection of these rhamnolipids in soil. This study examines (1) the efficiency of the biosurfactants produced by P. aeruginosa UG2 to mobilize pyrene from a contaminated sandy loam as compared to that of sodium dodecyl sulfate (SDS); (2) the injection procedures that might affect the efficiency of pyrene mobilization using UG2 biosurfactants; and (3) the co-transport of UG2 biosurfactants and pyrene. Based on the experimental results, it would be advantageous to use a high UG2 biosurfactant concentration, a high pore water velocity, and possibly a flow interruption of more than 15 h in order to reduce the injected volume and the duration of the treatment required. The 0.25% UG2 biosurfactant concentration greatly enhanced pyrene transport and could facilitate contaminant recovery.

  18. Laser Hair Removal

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Hair Removal, Laser A A A AFTER: Two laser hair removal treatments were performed. This picture is ... Procedure Overview With just the right type of laser or Intense Pulsed Light (IPL) technology, suitable hairs ...

  19. A novel Pseudomonas aeruginosa bacteriophage, Ab31, a chimera formed from temperate phage PAJU2 and P. putida lytic phage AF: characteristics and mechanism of bacterial resistance.

    Directory of Open Access Journals (Sweden)

    Libera Latino

    Full Text Available A novel temperate bacteriophage of Pseudomonas aeruginosa, phage vB_PaeP_Tr60_Ab31 (alias Ab31 is described. Its genome is composed of structural genes related to those of lytic P. putida phage AF, and regulatory genes similar to those of temperate phage PAJU2. The virion structure resembles that of phage AF and other lytic Podoviridae (S. enterica Epsilon 15 and E. coli phiv10 with similar tail spikes. Ab31 was able to infect P. aeruginosa strain PA14 and two genetically related strains called Tr60 and Tr162, out of 35 diverse strains from cystic fibrosis patients. Analysis of resistant host variants revealed different phenotypes, including induction of pigment and alginate overproduction. Whole genome sequencing of resistant variants highlighted the existence of a large deletion of 234 kbp in two strains, encompassing a cluster of genes required for the production of CupA fimbriae. Stable lysogens formed by Ab31 in strain Tr60, permitted the identification of the insertion site. During colonization of the lung in cystic fibrosis patients, P. aeruginosa adapts by modifying its genome. We suggest that bacteriophages such as Ab31 may play an important role in this adaptation by selecting for bacterial characteristics that favor persistence of bacteria in the lung.

  20. Co-Carriage of blaKPC-2 and blaNDM-1 in Clinical Isolates of Pseudomonas aeruginosa Associated with Hospital Infections from India.

    Directory of Open Access Journals (Sweden)

    Deepjyoti Paul

    Full Text Available Global spread of KPC poses to be a serious threat complicating treatment options in hospital settings. The present study investigates the genetic environment of blaKPC-2 among clinical isolates of Pseudomonas aeruginosa from a tertiary referral hospital of India. The study isolates were collected from different wards and clinics of Silchar Medical College and Hospital, India, from 2012-2013. The presence of blaKPC was confirmed by genotypic characterization followed by sequencing. Cloning of the blaKPC-2 gene was performed and the genetic environment of this gene was characterized as well. Transferability of the resistance gene was determined by transformation assay and Southern hybridization. Additionally, restriction mapping was also carried out. Two isolates of P. aeruginosa were found to harbor blaKPC-2, were resistant towards aminoglycosides, quinolone and β-lactam-β-lactamase inhibitor combination. In both the isolates, the resistance determinant was associated with class 1 integron and horizontally transferable. Both the isolates were co-harboring blaNDM-1. The first detection of this integron mediated blaKPC-2 coexisting with blaNDM-1 in P. aeruginosa from India is worrisome, and further investigation is required to track the gene cassette mediated blaKPC-2 in terms of infection control and to prevent the spread of this gene in hospitals as well as in the community.

  1. Platform Removal Observer Program Databases from 1987-present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Platform Removal Observer Program Data Underwater explosives are frequently used in the removal of oil and gas platforms. Since 1987, federal regulations required...

  2. Precision-engineering the Pseudomonas aeruginosa genome with two-step allelic exchange

    Science.gov (United States)

    Hmelo, Laura R.; Borlee, Bradley R.; Almblad, Henrik; Love, Michelle E.; Randall, Trevor E.; Tseng, Boo Shan; Lin, Chuyang; Irie, Yasuhiko; Storek, Kelly M.; Yang, Jaeun Jane; Siehnel, Richard J.; Howell, P. Lynne; Singh, Pradeep K.; Tolker-Nielsen, Tim; Parsek, Matthew R.; Schweizer, Herbert P.; Harrison, Joe J.

    2016-01-01

    Allelic exchange is an efficient method of bacterial genome engineering. This protocol describes the use of this technique to make gene knockouts and knockins, as well as single nucleotide insertions, deletions and substitutions in Pseudomonas aeruginosa. Unlike other approaches to allelic exchange, this protocol does not require heterologous recombinases to insert or excise selective markers from the target chromosome. Rather, positive and negative selection are enabled solely by suicide vector-encoded functions and host cell proteins. Here, mutant alleles, which are flanked by regions of homology to the recipient chromosome, are synthesized in vitro and then cloned into allelic exchange vectors using standard procedures. These suicide vectors are then introduced into recipient cells by conjugation. Homologous recombination then results in antibiotic resistant single-crossover mutants in which the plasmid has integrated site-specifically into the chromosome. Subsequently, unmarked double-crossover mutants are isolated directly using sucrose-mediated counter-selection. This two-step process yields seamless mutations that are precise to a single base pair of DNA. The entire procedure requires ~2 weeks. PMID:26492139

  3. Medium factors on anaerobic production of rhamnolipids by Pseudomonas aeruginosa SG and a simplifying medium for in situ microbial enhanced oil recovery applications.

    Science.gov (United States)

    Zhao, Feng; Zhou, Jidong; Han, Siqin; Ma, Fang; Zhang, Ying; Zhang, Jie

    2016-04-01

    Aerobic production of rhamnolipid by Pseudomonas aeruginosa was extensively studied. But effect of medium composition on anaerobic production of rhamnolipid by P. aeruginosa was unknown. A simplifying medium facilitating anaerobic production of rhamnolipid is urgently needed for in situ microbial enhanced oil recovery (MEOR). Medium factors affecting anaerobic production of rhamnolipid were investigated using P. aeruginosa SG (Genbank accession number KJ995745). Medium composition for anaerobic production of rhamnolipid by P. aeruginosa is different from that for aerobic production of rhamnolipid. Both hydrophobic substrate and organic nitrogen inhibited rhamnolipid production under anaerobic conditions. Glycerol and nitrate were the best carbon and nitrogen source. The commonly used N limitation under aerobic conditions was not conducive to rhamnolipid production under anaerobic conditions because the initial cell growth demanded enough nitrate for anaerobic respiration. But rhamnolipid was also fast accumulated under nitrogen starvation conditions. Sufficient phosphate was needed for anaerobic production of rhamnolipid. SO4(2-) and Mg(2+) are required for anaerobic production of rhamnolipid. Results will contribute to isolation bacteria strains which can anaerobically produce rhamnolipid and medium optimization for anaerobic production of rhamnolipid. Based on medium optimization by response surface methodology and ions composition of reservoir formation water, a simplifying medium containing 70.3 g/l glycerol, 5.25 g/l NaNO3, 5.49 g/l KH2PO4, 6.9 g/l K2HPO4·3H2O and 0.40 g/l MgSO4 was designed. Using the simplifying medium, 630 mg/l of rhamnolipid was produced by SG, and the anaerobic culture emulsified crude oil to EI24 = 82.5 %. The simplifying medium was promising for in situ MEOR applications. PMID:26925616

  4. Effect of pH on biologic degradation of Microcystis aeruginosa by alga-lysing bacteria in sequencing batch biofilm reactors

    Institute of Scientific and Technical Information of China (English)

    Hongjing LI; Mengli HAO; Jingxian LIU; Chen CHEN1; Zhengqiu FAN; Xiangrong WANG

    2012-01-01

    In this paper, the effect of pH on biological degradation of Microcystis aeruginosa by alga-lysing bacteria in laboratory-scale sequencing batch biofilm reactors (SBBRs) was investigated. After 10 d filming with waste activated sludge, the biological film could be formed, and the bioreactors in which laid polyolefin resin filler were used to treat algal culture. By comparing the removal efficiency of chlorophyll a at different aerobic time, the optimum time was determined as 5 h. Under pH 6.5, 7.5, and 8.5 conditions, the removal rates of Microcystis aeruginosa were respectively 75.9%, 83.6%, and 78.3% (in term of chlorophyll a), and that of Chemical Oxygen Demand (CODMn) were 30.6%, 35.8%, and 33.5%. While the removal efficiencies of ammonia nitrogen (NH+ -N) were all 100%. It was observed that the sequence of the removal efficiencies of algae, NH+ -N and organic matter were pH 7.5 〉 pH 8.5 〉 pH 6.5. The results showed that the dominant alga-lysing bacteria in the SBBRs was strain HM-01, which was identified as Bacillus sp. by Polymerase Chain Reaction (PCR) amplification of the 16S rRNA gene, Basic Local Alignment Search Tool (BLAST) analysis, and compar- ison with sequences in the GenBank nucleotide database. The algicidal activated substance which HM-01 strain excreted could withstand high temperature and pressure, also had better hydrophily and stronger polarity.

  5. Surgical Removal of the Thyroid Gland

    Medline Plus

    Full Text Available ... effective, more effective than perhaps laparoscopic or even robotic surgery for thyroid removal. Well I think the ... plastic closure. The patients recover very nicely. The robotic surgeries are requiring up to three surgeons. Oh, ...

  6. 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 ...

  7. 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...

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. Electrochemical treatment of water containing Microcystis aeruginosa in a fixed bed reactor with three-dimensional conductive diamond anodes.

    Science.gov (United States)

    Mascia, Michele; Monasterio, Sara; Vacca, Annalisa; Palmas, Simonetta

    2016-12-01

    An electrochemical treatment was investigated to remove Microcystis aeruginosa from water. A fixed bed reactor in flow was tested, which was equipped with electrodes constituted by stacks of grids electrically connected in parallel, with the electric field parallel to the fluid flow. Conductive diamond were used as anodes, platinised Ti as cathode. Electrolyses were performed in continuous and in batch recirculated mode with flow rates corresponding to Re from 10 to 160, current densities in the range 10-60Am(-2) and Cl(-) concentrations up to 600gm(-3). The absorbance of chlorophyll-a pigment and the concentration of products and by-products of electrolysis were measured. In continuous experiments without algae in the inlet stream, total oxidants concentrations as equivalent Cl2, of about 0.7gCl2m(-3) were measured; the maximum values were obtained at Re=10 and i=25Am(-2), with values strongly dependent on the concentration of Cl(-). The highest algae inactivation was obtained under the operative conditions of maximum generation of oxidants; in the presence of microalgae the oxidants concentrations were generally below the detection limit. Results indicated that most of the bulk oxidants electrogenerated is constituted by active chlorine. The prevailing mechanism of M. aeruginosa inactivation is the disinfection by bulk oxidants. The experimental data were quantitatively interpreted through a simple plug flow model, in which the axial dispersion accounts for the non-ideal flow behaviour of the system; the model was successfully used to simulate the performances of the reactor in the single-stack configuration used for the experiments and in multi-stack configurations. PMID:26988900

  19. 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.

  20. 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...

  1. 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...

  2. 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.

  3. 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 ...

  4. 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.

  5. 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....

  6. 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...

  7. 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...

  8. 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.

  9. 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...

  10. 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...

  11. 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.

  12. Asbestos removal in Shippingport Decommissioning Project

    International Nuclear Information System (INIS)

    The Shippingport Station Decommissioning Project (SSDP) is being performed under contract to the DOE by the General Electric Company and its integrated subcontractor, MK-Ferguson Company, as the Decommissioning Operations Contractor (DOC). During the planning of this project, it was found that asbestos was the primary insulating material which was used on the nuclear steam supply system and the plant heating system. The original decommissioning plan required that each subcontractor remove the asbestos from the particular component(s) they had to remove. However, since removal of the radioactivity-contaminated asbestos would require special procedures and worker training, the original decommissioning plan was modified so that a single subcontractor removed all of the asbestos prior to other decommissioning tasks. IT Corporation was selected as the asbestos removal subcontractor. Their approach to the project is described

  13. 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...

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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 ...

  20. 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...

  1. 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.

  2. 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 ...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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 ...

  9. 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 ...

  10. 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...

  11. 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

  12. 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...

  13. 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...

  14. [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

  15. 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...

  16. 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.

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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.

  10. 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.

  11. 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

  12. 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 ...

  13. 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...

  14. 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...

  15. 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....

  16. Hot Spot Removal System: System description

    International Nuclear Information System (INIS)

    Hazardous wastes contaminated with radionuclides, chemicals, and explosives exist across the Department of Energy complex and need to be remediated due to environmental concerns. Currently, an opportunity is being developed to dramatically reduce remediation costs and to assist in the acceleration of schedules associated with these wastes by deploying a Hot Spot Removal System. Removing the hot spot from the waste site will remove risk driver(s) and enable another, more cost effective process/option/remedial alternative (i.e., capping) to be applied to the remainder of the site. The Hot Spot Removal System consists of a suite of technologies that will be utilized to locate and remove source terms. Components of the system can also be used in a variety of other cleanup activities. This Hot Spot Removal System Description document presents technologies that were considered for possible inclusion in the Hot Spot Removal System, technologies made available to the Hot Spot Removal System, industrial interest in the Hot Spot Removal System''s subsystems, the schedule required for the Hot Spot Removal System, the evaluation of the relevant technologies, and the recommendations for equipment and technologies as stated in the Plan section

  17. Hot Spot Removal System: System description

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-09-01

    Hazardous wastes contaminated with radionuclides, chemicals, and explosives exist across the Department of Energy complex and need to be remediated due to environmental concerns. Currently, an opportunity is being developed to dramatically reduce remediation costs and to assist in the acceleration of schedules associated with these wastes by deploying a Hot Spot Removal System. Removing the hot spot from the waste site will remove risk driver(s) and enable another, more cost effective process/option/remedial alternative (i.e., capping) to be applied to the remainder of the site. The Hot Spot Removal System consists of a suite of technologies that will be utilized to locate and remove source terms. Components of the system can also be used in a variety of other cleanup activities. This Hot Spot Removal System Description document presents technologies that were considered for possible inclusion in the Hot Spot Removal System, technologies made available to the Hot Spot Removal System, industrial interest in the Hot Spot Removal System`s subsystems, the schedule required for the Hot Spot Removal System, the evaluation of the relevant technologies, and the recommendations for equipment and technologies as stated in the Plan section.

  18. 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

  19. 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.

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

    Science.gov (United States)

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

    2016-03-01

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

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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

  10. 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...

  11. Anaerobic survival of Pseudomonas aeruginosa by pyruvate fermentation requires an Usp-type stress protein

    DEFF Research Database (Denmark)

    Schreiber, K; Boes, N; Escbach, M; Jaensch, L; Wehland, J; Bjarnsholt, Thomas; Givskov, Michael Christian; Hentzer, M; Schobert, M

    2006-01-01

    induced synthesis of three enzymes involved in arginine fermentation, ArcA, ArcB, and ArcC, and the outer membrane protein OprL. Moreover, formation of two proteins of unknown function, PA3309 and PA4352, increased by factors of 72- and 22-fold, respectively. Both belong to the group of universal stress...... proteins (Usp). Long-term survival of a PA3309 knockout mutant by pyruvate fermentation was found drastically reduced. The oxygen-sensing regulator Anr controls expression of the PPA3309-lacZ reporter gene fusion after a shift to anaerobic conditions and further pyruvate fermentation. PA3309 expression was...... also found induced during the anaerobic and aerobic stationary phases. This aerobic stationary-phase induction is independent of the regulatory proteins Anr, RpoS, RelA, GacA, RhlR, and LasR, indicating a currently unknown mechanism of stationary-phase-dependent gene activation. PA3309 promoter...

  12. Different roles for anti-sigma factors in siderophore signalling pathways of Pseudomonas aeruginosa.

    Science.gov (United States)

    Mettrick, Karla A; Lamont, Iain L

    2009-12-01

    Group IV (extracytoplasmic function) sigma factors direct the expression of a large number of regulons in bacteria. The activities of many Group IV sigma factors are inhibited by members of a family of anti-sigma factor proteins, with appropriate environmental signals causing the sigma factor to be released for interaction with core RNA polymerase and consequent transcription of target genes. One subgroup of Group IV sigmas directs expression of genes for uptake of siderophores (iron-chelating compounds) by Gram-negative bacteria. The activities of these sigma factors are controlled by anti-sigma factors that span the cytoplasmic membrane. Binding of siderophore by a receptor protein in the outer membrane results in signal transduction from the periplasmic portion to the cytoplasmic portion of the appropriate anti-sigma factor, with consequent activity of the cognate sigma factor and upregulation of the gene encoding the receptor protein. We have investigated receptor/anti-sigma/sigma factor signalling pathways for uptake of the siderophores ferrichrome and desferrioxamine by Pseudomonas aeruginosa. In these pathways the 'anti-sigma' proteins are normally required for sigma factor activity and the cytoplasmic parts of the 'anti-sigmas' have 'pro-sigma' activity. We suggest that the family of anti-sigma factor proteins may be better considered as 'sigma regulators'. PMID:19889096

  13. Membrane localization and topology of the DnpA protein control fluoroquinolone tolerance in Pseudomonas aeruginosa.

    Science.gov (United States)

    Liebens, Veerle; Frangipani, Emanuela; Van der Leyden, Annelies; Fauvart, Maarten; Visca, Paolo; Michiels, Jan

    2016-09-01

    DnpA, a putative de-N-acetylase of the PIG-L superfamily, is required for antibiotic tolerance in Pseudomonas aeruginosa Exactly how dnpA (gene locus PA5002) directs the formation of antibiotic-tolerant persister cells is currently unknown. Previous research provided evidence for a role in surface-associated process(es), possibly in lipopolysaccharide biosynthesis. In silico sequence analysis of DnpA predicts a single transmembrane domain and Nin/Cout orientation of DnpA. In contrast, we here show that DnpA is an integral inner membrane protein containing two transmembrane domains, with the major C-terminal part located at the cytoplasmic face. Correct insertion into the inner membrane is necessary for DnpA to promote fluoroquinolone tolerance. The membrane localization of DnpA further supports its role in cell envelope-associated process(es). In addition to shedding light on the biological role of DnpA, this study highlights the risks of overreliance on the predictive value of bioinformatics tools and the importance of rigorous experimental validation of in silico predictions. PMID:27481702

  14. Multi-drug resistant Pseudomonas aeruginosa keratitis and its effective treatment with topical colistimethate

    Directory of Open Access Journals (Sweden)

    Samrat Chatterjee

    2016-01-01

    Full Text Available The purpose was to evaluate the clinical outcome in multi-drug resistant Pseudomonas aeruginosa (MDR-PA bacterial keratitis and report the successful use of an alternative antibiotic, topical colistimethate in some of them. The medical records of 12 culture-proven MDR-PA keratitis patients, all exhibiting in vitro resistance by Kirby–Bauer disc diffusion method to ≥ three classes of routinely used topical antibiotics were reviewed. Eight patients were treated with 0.3% ciprofloxacin or ofloxacin, 1 patient with 5% imipenem/cilastatin and 3 patients with 1.6% colistimethate. The outcomes in 8 eyes treated with only fluoroquinolones were evisceration in 4 eyes, therapeutic corneal graft in 1 eye, phthisis bulbi in 1 eye, and no improvement in 2 eyes. The eye treated with imipenem/cilastin required a therapeutic corneal graft. All the three eyes treated with 1.6% colistimethate healed. Colistimethate may prove to be an effective alternative antibiotic in the treatment of MDR-PA keratitis.

  15. Crystal structure and catalytic mechanism of pyridoxal kinase from Pseudomonas aeruginosa.

    Science.gov (United States)

    Kim, Meong Il; Hong, Minsun

    2016-09-01

    Pyridoxal kinase is a ubiquitous enzyme essential for pyridoxal 5'-phosphate (PLP) homeostasis since PLP is required for the catalytic activity of a variety of PLP-dependent enzymes involved in amino acid, lipid, and sugar metabolism as well as neurotransmitter biosynthesis. Previously, two catalytic mechanisms were proposed with regard to Pdx kinases, in which either the aspartate or the cysteine residue is involved as a catalytic residue. Because the Pdx kinase of Pseudomonas aeruginosa (PaPdxK) contains both residues, the catalytic mechanism of PaPdxK remains elusive. To elucidate the substrate-recognition and catalytic mechanisms of PaPdxK, the crystal structure of PaPdxK was determined at a 2.0 Å resolution. The PaPdxK structure possesses a channel that can accommodate substrates and a metallic cofactor. Our structure-based biochemical and mutational analyses in combination with modeling studies suggest that PaPdxK catalysis is mediated by an acid-base mechanism through the catalytic acid Asp225 and a helical dipole moment. PMID:27425248

  16. Crystal structures of the UDP-diacylglucosamine pyrophosphohydrase LpxH from Pseudomonas aeruginosa.

    Science.gov (United States)

    Okada, Chiaki; Wakabayashi, Hiroko; Kobayashi, Momoko; Shinoda, Akira; Tanaka, Isao; Yao, Min

    2016-01-01

    Lipid A (also known as endotoxin) is the hydrophobic portion of lipopolysaccharides. It is an essential membrane component required for the viability of gram-negative bacteria. The enzymes involved in its biosynthesis are attractive targets for the development of novel antibiotics. LpxH catalyzes the fourth step of the lipid A biosynthesis pathway and cleaves the pyrophosphate bond of UDP-2,3-diacylglucosamine to yield 2,3-diacylglucosamine 1-phosphate (lipid X) and UMP. Here we present the structures of LpxH from Pseudomonas aeruginosa (PaLpxH). PaLpxH consists of two domains: a catalytic domain that is homologous to the metallophosphoesterases and a helical insertion domain. Lipid X was captured in the crevice between these two domains, with its phosphate group facing the dinuclear metal (Mn(2+)) center and two acyl chains buried in the hydrophobic cavity. The structures reveal that a large conformational change occurs at the lipid X binding site surface upon the binding/release of the product molecule. Based on these observations, we propose a novel model for lipid X embedding, which involves the scissor-like movement of helix α6, resulting in the release of lipid X into the lipid bilayer. PMID:27609419

  17. Removal of radionuclides from household water

    International Nuclear Information System (INIS)

    Research upon methods for removing radionuclides from household water was initiated in Finland in 1995. Three research projects, of which two were carried out with National Technology Agency of Finland and one with CEC, have been completed by the end of 2002. One of the main objectives of the research was to compose a guidebook for consumers and water treatment companies. Radon can be removed from household water by aeration and by activated carbon filtration. Aerators that are well designed and set up can remove over 90% of waterborne radon. The best aerators have achieved removal efficiencies that are nearly 100%. However, setting up an aeration system requires thorough planning. Also, activated carbon filtration removes radon efficiently. The removal efficiencies have been over 90%, often nearly 100%. Depending on the water quality and usage, the carbon batch inside the filter needs to be changed every 2-3 years. Since activated carbon filters emit gamma radiation while in use, they should not be installed inside the dwelling but in a separate building or by the well. It is recommended that uranium be removed from drinking water by anion exchange, which is the most efficient removal method for this purpose. Typically, the removal efficiencies are nearly 100%. The one exception is the so called tap filter, the removal efficiency of which depends on uranium concentration in raw water and the rate of water flow. High saline concentration in water may extricate uranium from ion exchange resin. Changes in plumbing pressure or pH-value do not have any significant influence in uranium retention. Removal efficiencies of lead and polonium vary a lot depending on the chemical form in which they occur in water. They can be reliably removed from water by reverse osmosis only. Other treatment methods, such as ion exchange and activated carbon filtration, remove lead and polonium partly. Lead and polonium are removed more efficiently when they are bound onto smaller particles

  18. 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...

  19. 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...

  20. 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...