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Sample records for pseudomonas fluorescens bacteremia

  1. Plant growth promotion by Pseudomonas fluorescens

    NARCIS (Netherlands)

    Cheng, X.

    2016-01-01

    Pseudomonas fluorescens is a Gram-negative rod shaped bacterium that has a versatile metabolism and is widely spread in soil and water. P. fluorescens strain SBW25 (Pf.SBW25) is a well-known model strain to study bacterial evolution, plant colonization and biocontrol of plant diseases. It produces

  2. Growth of Pseudomonas fluorescens on Cassava Starch ...

    African Journals Online (AJOL)

    This involved hydrolysis of starch extracted from freshly harvested cassava tubers using enzyme-enzyme method of hydrolysis, followed by aerobic fermentation of Pseudomonas fluorescens on a mixture of the hydrolysate and nutrient media in a fermentor in batch cultures. The reducing sugar hydrolysate served as the ...

  3. Pseudomonas fluorescens' view of the periodic table.

    Science.gov (United States)

    Workentine, Matthew L; Harrison, Joe J; Stenroos, Pernilla U; Ceri, Howard; Turner, Raymond J

    2008-01-01

    Growth in a biofilm modulates microbial metal susceptibility, sometimes increasing the ability of microorganisms to withstand toxic metal species by several orders of magnitude. In this study, a high-throughput metal toxicity screen was initiated with the aim of correlating biological toxicity data in planktonic and biofilm cells to the physiochemical properties of metal ions. To this end, Pseudomonas fluorescens ATCC 13525 was grown in the Calgary Biofilm Device (CBD) and biofilms and planktonic cells of this microorganism were exposed to gradient arrays of different metal ions. These arrays included 44 different metals with representative compounds that spanned every group of the periodic table (except for the halogens and noble gases). The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum biofilm eradication concentration (MBEC) values were obtained after exposing the biofilms to metal ions for 4 h. Using these values, metal ion toxicity was correlated to the following ion-specific physicochemical parameters: standard reduction-oxidation potential, electronegativity, the solubility product of the corresponding metal-sulfide complex, the Pearson softness index, electron density and the covalent index. When the ions were grouped according to outer shell electron structure, we found that heavy metal ions gave the strongest correlations to these parameters and were more toxic on average than the other classes of the ions. Correlations were different for biofilms than for planktonic cells, indicating that chemical mechanisms of metal ion toxicity differ between the two modes of growth. We suggest that biofilms can specifically counter the toxic effects of certain physicochemical parameters, which may contribute to the increased ability of biofilms to withstand metal toxicity.

  4. Detection of Pseudomonas fluorescens from broth, water and ...

    African Journals Online (AJOL)

    Loop mediated isothermal amplification is rapid, highly sensitive and specifically developed method for detection of bacterial infections. AprX gene for alkaline metalloprotease of Pseudomonas fluorescens was used to design four primers and loop mediated isothermal amplification (LAMP) conditions were standardized for ...

  5. Characterization and identification of Pseudomonas fluorescens ...

    African Journals Online (AJOL)

    user

    2011-01-24

    Jan 24, 2011 ... fluorescens can be used for bioremediation of textile effluents containing CV dye in sequential cycles. Key words: Crystal violet, ... extensively in textile dyeing and dye-stuff manufacturing industries, in human and ... nuclear magnetic resonance spectra of the test samples were run at Brukar AC 200 M Hz in ...

  6. The evolution of a pleiotropic fitness tradeoff in Pseudomonas fluorescens

    OpenAIRE

    MacLean, R. Craig; Bell, Graham; Rainey, Paul B.

    2004-01-01

    The evolution of ecological specialization is expected to carry a cost, due to either antagonistic pleiotropy or mutation accumulation. In general, it has been difficult to distinguish between these two possibilities. Here, we demonstrate that the experimental evolution of niche-specialist genotypes of the bacterium Pseudomonas fluorescens that colonize the air–broth interface of spatially structured microcosms is accompanied by pleiotropic fitness costs in terms of reduced carbon catabolism....

  7. Lethality and Developmental Delay of Drosophila melanogaster Following Ingestion of Selected Pseudomonas fluorescens Strains

    Science.gov (United States)

    Pseudomonas fluorescens secretes antimicrobial compounds that promote plant health and provide protection from pathogens. We used a non-invasive feeding assay to study the toxicity of P. fluorescens strains Pf0-1, SBW25, and Pf-5 to Drosophila melanogaster. The three strains of P. fluorescens varie...

  8. Pseudomonas fluorescens subsp. cellulosa: an alternative model for bacterial cellulase.

    Science.gov (United States)

    Hazlewood, G P; Laurie, J I; Ferreira, L M; Gilbert, H J

    1992-03-01

    Pseudomonas fluorescens subsp. cellulosa, a Gram-negative soil bacterium, can utilize crystalline cellulose or xylan as main sources of carbon and energy. Synthesis of endoglucanases and xylanases is induced by Avicel, filter paper, carboxymethylcellulose or xylan and is repressed by cellobiose, glucose or xylose. These enzymes are secreted into the culture supernatant fluid and do not form aggregates or associate with the cell surface. Cells of Ps. fluorescens subsp. cellulosa do not adhere to cellulose. In cultures containing Avicel or filter paper, a significant proportion of the secreted cellulase and xylanase activities becomes tightly bound to the insoluble cellulose. Western blotting has revealed that endoglucanase B, xylanase A and a cellodextrinase encoded by genes previously isolated from Ps. fluorescens subsp. cellulosa and expressed in Escherichia coli, are synthesized by the pseudomonad under a variety of conditions. These enzymes appear to be post-translationally modified, probably through glycosylation. Overall, it appears that the cellulase/hemicellulase system of Ps. fluorescens subsp. cellulosa differs from the model established for celluloytic anaerobes such as Clostridium thermocellum.

  9. MICROBIAL BIOFILMS PRODUCED BY PSEUDOMONAS FLUORESCENS ON SOLID SURFACES

    Directory of Open Access Journals (Sweden)

    Dagmar Kozelová

    2011-04-01

    Full Text Available Normal 0 21 false false false MicrosoftInternetExplorer4 Normal 0 21 false false false MicrosoftInternetExplorer4 A biofilm is a complex aggregation of microorganisms growing on a solid substrate. Biofilms are characterized by structural heterogeneity, genetic diversity, complex community interactions, and an extracellular matrix of polymeric substances. The experimental part was focused on the adhesion of bacterial cells under static conditions and testing the effectiveness of disinfectants on created biofilm. In laboratory conditions we prepared and formed the bacterial biofilms Pseudomonas fluorescens in the four test surfaces of stainless steel, glass and plastic materials - PE (polyethylene and EPDM (ethylene propylene diene monomer. Over the next 72 hours and 72 hours were observed numbers of adhesion bacterial cells of P. fluorescens on solid surfaces of tested materials. The highest values adhesion cells reached P. fluorescens cells after 72 hours of cultivation on plastic surfaces, where  was increased in adhesion bacterial cells for EPDM in the values of 105 CFU/cm2 and for PE up to 106 CFU/cm2. The subsequent repeated 72-hour cultivation P. fluorescens was an increase (growth in the number of adhesion bacterial cells to all tested surfaces.doi:10.5219/18  

  10. Combined inoculation of Pseudomonas fluorescens and Trichoderma harzianum for enhancing plant growth of vanilla (Vanilla planifolia).

    Science.gov (United States)

    Sandheep, A R; Asok, A K; Jisha, M S

    2013-06-15

    This study was conducted to evaluate the plant growth promoting efficiency of combined inoculation of rhizobacteria on Vanilla plants. Based on the in vitro performance of indigenous Trichoderma spp. and Pseudomonas spp., four effective antagonists were selected and screened under greenhouse experiment for their growth enhancement potential. The maximum percentage of growth enhancement were observed in the combination of Trichoderma harzianum with Pseudomonas fluorescens treatment followed by Pseudomonas fluorescens, Trichoderma harzianum, Pseudomonas putida and Trichoderma virens, respectively in decreasing order. Combined inoculation of Trichoderma harzianum and Pseudomonas fluorescens registered the maximum length of vine (82.88 cm), highest number of leaves (26.67/plant), recorded the highest fresh weight of shoots (61.54 g plant(-1)), fresh weight of roots (4.46 g plant(-1)) and dry weight of shoot (4.56 g plant(-1)) where as the highest dry weight of roots (2.0806 g plant(-1)) were achieved with treatments of Pseudomonas fluorescens. Among the inoculated strains, combined inoculation of Trichoderma harzianum and Pseudomonas fluorescens recorded the maximum nitrogen uptake (61.28 mg plant(-1)) followed by the combined inoculation of Trichoderma harzianum (std) and Pseudomonas fluorescens (std) (55.03 mg plant(-1)) and the highest phosphorus uptake (38.80 mg plant(-1)) was recorded in dual inoculation of Trichoderma harzianum and Pseudomonas fluorescens.

  11. Factors Affecting Zebra Mussel Kill by the Bacterium Pseudomonas fluorescens

    Energy Technology Data Exchange (ETDEWEB)

    Daniel P. Molloy

    2004-02-24

    The specific purpose of this research project was to identify factors that affect zebra mussel kill by the bacterium Pseudomonas fluorescens. Test results obtained during this three-year project identified the following key variables as affecting mussel kill: treatment concentration, treatment duration, mussel siphoning activity, dissolved oxygen concentration, water temperature, and naturally suspended particle load. Using this latter information, the project culminated in a series of pipe tests which achieved high mussel kill inside power plants under once-through conditions using service water in artificial pipes.

  12. Adaptive synonymous mutations in an experimentally evolved Pseudomonas fluorescens population

    DEFF Research Database (Denmark)

    Bailey, Susan; Hinz, Aaron; Kassen, Rees

    2014-01-01

    Conventional wisdom holds that synonymous mutations, nucleotide changes that do not alter the encoded amino acid, have no detectable effect on phenotype or fitness. However, a growing body of evidence from both comparative and experimental studies suggests otherwise. Synonymous mutations have been...... in an experimentally evolved population of Pseudomonas fluorescens. We show experimentally that these mutations increase fitness by an amount comparable to non-synonymous mutations and that the fitness increases stem from increased gene expression. These results provide unequivocal evidence that synonymous mutations...... can drive adaptive evolution and suggest that this class of mutation may be underappreciated as a cause of adaptation and evolutionary dynamics....

  13. Uji Lapangan Formula Cair Pseudomonas fluorescens P60 terhadap Layu Fusarium pada Tanaman Tomat

    Directory of Open Access Journals (Sweden)

    Loekas Soesanto

    2011-12-01

    Full Text Available A research aimed at knowing 1 the effect of Pseudomonas fluorescens P60 in liquid formula on Fusarium wilt of tomato, 2 the effect of P. fluorescens P60 in the formula on tomato growth and yield, and 3 P. fluorescens P60 mechanisms on tomata was carried out at tomato field of Selomoyo Village, Kaliangkrik Subdistrict, Magelang Regency at altitude of 826 m above sea level. Randomized block design was used with seven treatments and four replicates. The treatments were control, with P. fluorescens P60 soaked for 15 min and without fungicide, pathogen without P. fluorescens P60 with fungicide (PBG1, pathogen with P. fluorescens P60 without fungicide, pathogen with pouring P. fluorescens P60 1, 3, and 5 times. Result indicated that application of formulated P. fluorescens P60 for 5 times decreased the disease intensity as high as 26.77%, and late population of the pathogen but increased P. fluorescens P60 as high as 4.54×1010 cfu ml-1. P. fluorescens P60 affected growth and yield of tomato. P. Fluorescens P60 induced tomato resistance by increasing qualitatively its phenolic compound content (saponin, tannin, glycoside.   Penelitian dengan tujuan untuk mengetahui: 1 pengaruh Pseudomonas fluorescens P60 dalam formula cair terhadap penyakit layu fusarium pada tanaman tomat, 2 pengaruh P. fluorescens P60 dalam formula cair terhadap pertumbuhan dan produksi tanaman tomat, dan 3 mekanisme P. fluorescens P60 pada tanaman tomat dilakukan di lahan Desa Selomoyo, Kecamatan Kaliangkrik, Kabupaten Magelang dengan ketinggian 826 m di atas permukaan laut. Penelitian menggunakan Rancangan Acak Kelompok (RAK, dengan 7 perlakuan dan jumlah ulangan 4 kali, dan setiap unit terdiri atas 8 tanaman. Perlakuan tersebut meliputi kontrol; dengan P. fluorescens P60 rendam 15 menit dan tanpa fungisida; dengan patogen; tanpa P. fluorescens P60; dengan fungisida (PBG1; patogen, tanpa P. fluorescens P60, tanpa fungisida; patogen, dengan penyiraman P. fluorescens P60 1 kali

  14. Effect of Pseudomonas fluorescens on Buried Steel Pipeline Corrosion.

    Science.gov (United States)

    Spark, Amy J; Law, David W; Ward, Liam P; Cole, Ivan S; Best, Adam S

    2017-08-01

    Buried steel infrastructure can be a source of iron ions for bacterial species, leading to microbiologically influenced corrosion (MIC). Localized corrosion of pipelines due to MIC is one of the key failure mechanisms of buried steel pipelines. In order to better understand the mechanisms of localized corrosion in soil, semisolid agar has been developed as an analogue for soil. Here, Pseudomonas fluorescens has been introduced to the system to understand how bacteria interact with steel. Through electrochemical testing including open circuit potentials, potentiodynamic scans, anodic potential holds, and electrochemical impedance spectroscopy it has been shown that P. fluorescens increases the rate of corrosion. Time for oxide and biofilms to develop was shown to not impact on the rate of corrosion but did alter the consistency of biofilm present and the viability of P. fluorescens following electrochemical testing. The proposed mechanism for increased corrosion rates of carbon steel involves the interactions of pyoverdine with the steel, preventing the formation of a cohesive passive layer, after initial cell attachment, followed by the formation of a metal concentration gradient on the steel surface.

  15. Genomic and Genetic Diversity within the Pseudomonas fluorescens Complex.

    Directory of Open Access Journals (Sweden)

    Daniel Garrido-Sanz

    Full Text Available The Pseudomonas fluorescens complex includes Pseudomonas strains that have been taxonomically assigned to more than fifty different species, many of which have been described as plant growth-promoting rhizobacteria (PGPR with potential applications in biocontrol and biofertilization. So far the phylogeny of this complex has been analyzed according to phenotypic traits, 16S rDNA, MLSA and inferred by whole-genome analysis. However, since most of the type strains have not been fully sequenced and new species are frequently described, correlation between taxonomy and phylogenomic analysis is missing. In recent years, the genomes of a large number of strains have been sequenced, showing important genomic heterogeneity and providing information suitable for genomic studies that are important to understand the genomic and genetic diversity shown by strains of this complex. Based on MLSA and several whole-genome sequence-based analyses of 93 sequenced strains, we have divided the P. fluorescens complex into eight phylogenomic groups that agree with previous works based on type strains. Digital DDH (dDDH identified 69 species and 75 subspecies within the 93 genomes. The eight groups corresponded to clustering with a threshold of 31.8% dDDH, in full agreement with our MLSA. The Average Nucleotide Identity (ANI approach showed inconsistencies regarding the assignment to species and to the eight groups. The small core genome of 1,334 CDSs and the large pan-genome of 30,848 CDSs, show the large diversity and genetic heterogeneity of the P. fluorescens complex. However, a low number of strains were enough to explain most of the CDSs diversity at core and strain-specific genomic fractions. Finally, the identification and analysis of group-specific genome and the screening for distinctive characters revealed a phylogenomic distribution of traits among the groups that provided insights into biocontrol and bioremediation applications as well as their role as

  16. Isolation and characterization of a T7-like lytic phage for Pseudomonas fluorescens

    OpenAIRE

    Neubauer Peter; Sillankorva Sanna; Azeredo Joana

    2008-01-01

    Background: Despite the proven relevance of Pseudomonas fluorescens as a spoilage microorganism in milk, fresh meats and refrigerated food products and the recognized potential of bacteriophages as sanitation agents, so far no phages specific for P. fluorescens isolates from dairy industry have been closely characterized in view of their lytic efficiency. Here we describe the isolation and characterization of a lytic phage capable to infect a variety of P. fluorescens strains i...

  17. ANOMALOUS BLUE COLOURING OF MOZZARELLA CHEESE INTENTIONALLY CONTAMINATED WITH PIGMENT PRODUCING STRAINS OF PSEUDOMONAS FLUORESCENS

    Directory of Open Access Journals (Sweden)

    P. Sechi

    2011-04-01

    Full Text Available In summer 2010 a large outbreak of anomalous blue coloration of mozzarella cheese was recorded in Italy and some northern European countries. Official laboratory analysis and health authorities linked the outbreak to the contamination of processing water with strains of Pseudomonas fluorescens, although several expert raised the question of how to unequivocally link the blue coloring to the presence of the micro-organism. In an attempt to set-up a method to determine whether a given Pseudomonas spp. strain is responsible of the defect, an in vitro system for the evaluation of blue colouring of mozzarella cheese intentionally contaminated with strains of Pseudomonas fluorescens. was developed The system is aimed to ascertain whether P. fluorescens strains, isolated from mozzarella cheese with anomalous blue coloration, are able to reproduce the blue coloration under controlled experimental condition. 96 trials of experimental inoculation of mozzarella cheese in different preservation liquids, were conducted using various suspension of Pseudomonas spp. (P. fluorescens ATCC 13525, P. fluorescens CFBP 3150, one P. fluorescens field strain isolated from blue-colored mozzarella cheese and P. aeruginosa ATCC 10145 as positive control at different concentrations and incubated at different temperatures. Growth curve of all Pseudomonas spp. strains tested demonstrated that after three days of incubation the concentration was generally higher than 106 CFU/g of mozzarella cheese incubated in Tryptic Soy Broth (TSB, and higher than 105 CFU/g of mozzarella cheese incubated in preservation liquid. All mozzarella cheeses inoculated with the field strain of Pseudomonas fluorescens showed the characteristic anomalous blue coloration, which is often associated with Pseudomonas fluorescens contamination of water used during mozzarella cheesemaking. With the proposed system, which enabled a considerable amount of samples to be analysed under controlled experimental

  18. High pressure inactivation of Pseudomonas in black truffle - comparison with Pseudomonas fluorescens in tryptone soya broth

    Science.gov (United States)

    Ballestra, Patricia; Verret, Catherine; Cruz, Christian; Largeteau, Alain; Demazeau, Gerard; El Moueffak, Abdelhamid

    2010-03-01

    Pseudomonas is one of the most common genera in black Perigord truffle. Its inactivation by high pressure (100-500 MPa/10 min) applied on truffles at sub-zero or low temperatures was studied and compared with those of Pseudomonas fluorescens in tryptone soya broth. Pressurization of truffles at 300 MPa/4 °C reduced the bacterial count of Pseudomonas by 5.3 log cycles. Higher pressures of 400 or 500 MPa, at 4 °C or 20 °C, allowed us to slightly increase the level of destruction to the value of ca. 6.5 log cycles but did not permit us to completely inactivate Pseudomonas. The results showed a residual charge of about 10 CFU/g. Pressure-shift freezing of truffles, which consists in applying a pressure of 200 MPa/-18 °C for 10 min and then quickly releasing this pressure to induce freezing, reduced the population of Pseudomonas by 3.3 log cycles. The level of inactivation was higher than those obtained with conventional freezing. Endogenous Pseudomonas in truffle was shown to be more resistant to high pressure treatments than P. fluorescens used for inoculation of broths.

  19. Three Strains of Pseudomonas fluorescens Exhibit Differential Toxicity Against Drosophila melanogaster

    Science.gov (United States)

    Three strains of Pseudomonas fluorescens were tested for toxicity to Drosophila melanogaster in an insect feeding assay. Insect eggs were placed on the surface of a non-nutritive agar plate supplemented with a food source that was non-inoculated or inoculated with P. fluorescens Pf0-1, SBW25, or Pf-...

  20. Bacteriocins and the assembly of natural Pseudomonas fluorescens populations.

    Science.gov (United States)

    Bruce, J B; West, S A; Griffin, A S

    2017-02-01

    When competing for space and resources, bacteria produce toxins known as bacteriocins to gain an advantage over competitors. Recent studies in the laboratory have confirmed theoretical predictions that bacteriocin production can determine coexistence, by eradicating sensitive competitors or driving the emergence of resistant genotypes. However, there is currently limited evidence that bacteriocin-mediated competition influences the coexistence and distribution of genotypes in natural environments, and what factors drive interactions towards inhibition remain unclear. Using natural soil populations of Pseudomonas fluorescens, we assessed the ability of the isolates to inhibit one another with respect to spatial proximity in the field, genetic similarity and niche overlap. The majority of isolates were found to produce bacteriocins; however, widespread resistance between coexisting isolates meant relatively few interactions resulted in inhibition. When inhibition did occur, it occurred more frequently between ecologically similar isolates. However, in contrast with results from other natural populations, we found no relationship between the frequency of inhibition and the genetic similarity of competitors. Our results suggest that bacteriocin production plays an important role in mediating competition over resources in natural settings and, by selecting for isolates resistant to local bacteriocin production, can influence the assembly of natural populations of P. fluorescens. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  1. Boolean models of biosurfactants production in Pseudomonas fluorescens.

    Directory of Open Access Journals (Sweden)

    Adrien Richard

    Full Text Available Cyclolipopeptides (CLPs are biosurfactants produced by numerous Pseudomonas fluorescens strains. CLP production is known to be regulated at least by the GacA/GacS two-component pathway, but the full regulatory network is yet largely unknown. In the clinical strain MFN1032, CLP production is abolished by a mutation in the phospholipase C gene (plcC and not restored by plcC complementation. Their production is also subject to phenotypic variation. We used a modelling approach with Boolean networks, which takes into account all these observations concerning CLP production without any assumption on the topology of the considered network. Intensive computation yielded numerous models that satisfy these properties. All models minimizing the number of components point to a bistability in CLP production, which requires the presence of a yet unknown key self-inducible regulator. Furthermore, all suggest that a set of yet unexplained phenotypic variants might also be due to this epigenetic switch. The simplest of these Boolean networks was used to propose a biological regulatory network for CLP production. This modelling approach has allowed a possible regulation to be unravelled and an unusual behaviour of CLP production in P. fluorescens to be explained.

  2. Bioreporter pseudomonas fluorescens HK44 immobilized in a silica matrix

    Directory of Open Access Journals (Sweden)

    Trogl J.

    2003-01-01

    Full Text Available The bioluminescent bioreporter Pseudomonas fluorescens HK44, the whole cell bacterial biosensor that responds to naphthalene and its metabolites via the production of visible light, was immobilized into a silica matrix by the sol-gel technique. The bioluminescence intensities were measured in the maximum of the bioluminescence band at X = 500 nm. The immobilized cells (>105 cells per g silica matrix produced light after induction by salicylate (cone. > 10 g/l, naphthalene and aminobenzoic acid. The bioluminescence intensities induced by 2,3-dihydroxynaphthalene 3-hydroxybenzoic acid and 4-hydroxybenzoic acid were comparable to a negative control. The cells in the silica layers on glass slides produced light in response to the presence of an inductor at least 8 months after immobilization, and >50 induction cycles. The results showed that these test slides could be used as assays for the multiple determination of water pollution.

  3. The cellodextrinase from Pseudomonas fluorescens subsp. cellulosa consists of multiple functional domains

    National Research Council Canada - National Science Library

    Ferreira, L M; Hazlewood, G P; Barker, P J; Gilbert, H J

    1991-01-01

    A genomic library of Pseudomonas fluorescens subsp. cellulosa DNA was constructed in pUC18 and Escherichia coli recombinants expressing 4-methylumbelliferyl beta-D-cellobioside-hydrolysing activity (MUCase) were isolated...

  4. Promotion of plant growth by Pseudomonas fluorescens strain SS101 via novel volatile organic compounds

    NARCIS (Netherlands)

    Park, Yong-Soon; Dutta, Swarnalee; Ann, Mina; Raaijmakers, Jos M.; Park, Kyungseok

    2015-01-01

    Abstract Volatile organic compounds (VOCs) from plant growth-promoting rhizobacteria (PGPR) play key roles in modulating plant growth and induced systemic resistance (ISR) to pathogens. Despite their significance, the physiological functions of the specific VOCs produced by Pseudomonas fluorescens

  5. EXAFS Study of Uranyl Complexation at Pseudomonas fluorescens Cell Surfaces

    Science.gov (United States)

    Bencheikh, R.; Bargar, J. R.; Tebo, B. M.

    2002-12-01

    Little is known about the roles of microbial biomass as a sink and source for uranium in contaminated aquifers, nor of the impact of bacterial biochemistry on uranium speciation in the subsurface. A significant role is implied by the high affinities of both Gram positive and Gram negative cells for binding uranyl (UO2{ 2+}). In the present study, Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy was used to identify membrane functional groups involved in uranyl binding to the Gram negative bacterium Pseudomonas fluorescens from pH 3 to pH 8. Throughout this pH-range, EXAFS spectra can be described primarily in terms of coordination of carboxylic groups to uranyl. U-C distances characteristic of 4-, 5- and 8- membered rings were observed, as well as the possibility of phosphato groups. Both shell-by-shell fits and principle component analyses indicate that the functional groups involved in binding of uranyl to the cell surface do not vary systematically across the pH range investigated. This result contrasts with EXAFS results of uranyl sorbed to Gram positive bacteria, and suggests an important role for long-chain carboxylate-terminated membrane functional groups in binding uranyl.

  6. Diluent sensitivity in thermally stressed cells of pseudomonas fluorescens.

    Science.gov (United States)

    Gray, R J; Ordal, Z J; Witter, L D

    1977-01-01

    Thermally injured cells of Pseudomonas fluorescens were unable to produce colonies on Trypticase soy agar (TSA) after dilution with 0.1% peptone. Nutritional exigency could not be used as the criterion for this injury, since varying the composition of the plating medium had little effect on the number of colonies that developed. The injured cells had no requirement for compounds known to leak out during the heat treatment in order to recover. The cells did not exhibit injury if dilution preceded heat treatment on the plating medium, demonstrating that the heat treatment sensitized the cells to the trauma of dilution. Substitution of 0.1% peptone with growth medium as the diluent largely offset the previously observed drop in TSA count. Little difference in survival was observed when monosodium glutamate or the balance of the defined medium was used as the diluent. The diluent effect was ionic rather than osmotic. The presence of cations was important in maintaining the integrity of the injured cell, and divalent cations enhanced this protective effect. The role of these cations at the level of the cell envelope is discussed. PMID:406839

  7. Global control in Pseudomonas fluorescens mediating antibiotic synthesis and suppression of black root rot of tobacco.

    OpenAIRE

    Laville, J; Voisard, C; C. Keel; Maurhofer, M.; Défago, G; Haas, D

    1992-01-01

    Pseudomonas fluorescens CHA0 colonizes plant roots, produces several secondary metabolites in stationary growth phase, and suppresses a number of plant diseases, including Thielaviopsis basicola-induced black root rot of tobacco. We discovered that mutations in a P. fluorescens gene named gacA (for global antibiotic and cyanide control) pleiotropically block the production of the secondary metabolites 2,4-diacetylphloroglucinol (Phl), HCN, and pyoluteorin. The gacA mutants of strain CHA0 have...

  8. Bioremediation of crude oil contaminated soil by bioaugmentation of Pseudomonas fluorescens NS1.

    Science.gov (United States)

    Barathi, S; Vasudevan, N

    2003-09-01

    A feasibility study was conducted to evaluate the efficiency of Pseudomonas fluorescens NS1 bioaugmented to stimulate in situ bioremediation of crude oil-contaminated soil with different amendments in treatment units. Pure culture of P. fluorescens NS1 was isolated from a petroleum-contaminated soil. The rate of degradation of petroleum hydrocarbons by the indigenous soil microflora and in the presence of P. fluorescens NS1 was assessed with the addition of nutrients and bulking agents for a period of about 35 days. The study showed that addition of wheat bran as bulking agent rapidly enhanced bioremediation of crude oil-contaminated soil compared to amendments in other treatment units.

  9. The effect of phylogenetically different bacteria on the fitness of Pseudomonas fluorescens in sand microcosms.

    Directory of Open Access Journals (Sweden)

    Olaf Tyc

    Full Text Available In most environments many microorganisms live in close vicinity and can interact in various ways. Recent studies suggest that bacteria are able to sense and respond to the presence of neighbouring bacteria in the environment and alter their response accordingly. This ability might be an important strategy in complex habitats such as soils, with great implications for shaping the microbial community structure. Here, we used a sand microcosm approach to investigate how Pseudomonas fluorescens Pf0-1 responds to the presence of monocultures or mixtures of two phylogenetically different bacteria, a Gram-negative (Pedobacter sp. V48 and a Gram-positive (Bacillus sp. V102 under two nutrient conditions. Results revealed that under both nutrient poor and nutrient rich conditions confrontation with the Gram-positive Bacillus sp. V102 strain led to significant lower cell numbers of Pseudomonas fluorescens Pf0-1, whereas confrontation with the Gram-negative Pedobacter sp. V48 strain did not affect the growth of Pseudomonas fluorescens Pf0-1. However, when Pseudomonas fluorescens Pf0-1 was confronted with the mixture of both strains, no significant effect on the growth of Pseudomonas fluorescens Pf0-1 was observed. Quantitative real-time PCR data showed up-regulation of genes involved in the production of a broad-spectrum antibiotic in Pseudomonas fluorescens Pf0-1 when confronted with Pedobacter sp. V48, but not in the presence of Bacillus sp. V102. The results provide evidence that the performance of bacteria in soil depends strongly on the identity of neighbouring bacteria and that inter-specific interactions are an important factor in determining microbial community structure.

  10. Transposon Tn5 mutagenesis of pseudomonas fluorescens to isolate mutants deficient in antibacterial activity.

    Science.gov (United States)

    Rajendran, N; Jahn, D; Jayaraman, K; Marahiel, M A

    1994-01-15

    Pseudomonas fluorescens was subjected to insertion mutagenesis studies using the transposon Tn5-GM to generate mutants deficient in antibacterial activity minus mutants. The transposon located on the temperature-sensitive plasmid pCHR84 was conjugally transferred into the non-pathogenic pseudomonad using the triparental mating procedure. Random integration of Tn5-GM into the chromosome of P. fluorescens was achieved by heat treatment of the transformed cells at 42 degrees C. Approximately 2% of transconjugants revealed an auxotrophic phenotype indicating efficient integration of the employed transposon into the chromosome of P. fluorescens. One transposon insertion mutant was obtained showing an antibacterial activity minus phenotype. This mutant (MM-7) was found to be defective in the production of an unidentified antibacterial compound against B. subtilis. These results introduce Tn5 transposon mutagenesis as a new useful tool for the molecular analysis of P. fluorescens.

  11. Chromium phytoextraction from tannery effluent-contaminated soil by Crotalaria juncea infested with Pseudomonas fluorescens.

    Science.gov (United States)

    Agarwal, Anamika; Singh, Harminder Pal; Rai, J P N

    2014-01-01

    The aim of present study was to remediate chromium (Cr)-contaminated soil by Crotalaria juncea in the presence of Pseudomonas fluorescens. Inoculation of P. fluorescens in pot soil grown with C. juncea significantly increased (~2-fold) the water-soluble (Ws) and exchangeable (Ex) Cr contents in contaminated soil under greenhouse condition. It also enhanced the chlorophyll content by 92 % and plant biomass by 99 % as compared to the uninoculated C. juncea plant. The analysis showed that root and shoot uptake of Cr in C. juncea inoculated by P. fluorescens was 3.08- and 2.82-fold, respectively. This research showed that the association of C. juncea and P. fluorescens could be a promising technology for increasing the soil Cr bioavailability and plant growth for successful phytoextraction of Cr from the contaminated soil.

  12. Switching Catalysis from Hydrolysis to Perhydrolysis in Pseudomonas fluorescens Esterase

    Energy Technology Data Exchange (ETDEWEB)

    Yin, D.; Bernhardt, P; Morley, K; Jiang, Y; Cheeseman, J; Purpero, V; Schrag, J; Kazlauskas, R

    2010-01-01

    Many serine hydrolases catalyze perhydrolysis, the reversible formation of peracids from carboxylic acids and hydrogen peroxide. Recently, we showed that a single amino acid substitution in the alcohol binding pocket, L29P, in Pseudomonas fluorescens (SIK WI) aryl esterase (PFE) increased the specificity constant of PFE for peracetic acid formation >100-fold [Bernhardt et al. (2005) Angew. Chem., Int. Ed. 44, 2742]. In this paper, we extend this work to address the three following questions. First, what is the molecular basis of the increase in perhydrolysis activity? We previously proposed that the L29P substitution creates a hydrogen bond between the enzyme and hydrogen peroxide in the transition state. Here we report two X-ray structures of L29P PFE that support this proposal. Both structures show a main chain carbonyl oxygen closer to the active site serine as expected. One structure further shows acetate in the active site in an orientation consistent with reaction by an acyl-enzyme mechanism. We also detected an acyl-enzyme intermediate in the hydrolysis of {var_epsilon}-caprolactone by mass spectrometry. Second, can we further increase perhydrolysis activity? We discovered that the reverse reaction, hydrolysis of peracetic acid to acetic acid and hydrogen peroxide, occurs at nearly the diffusion limited rate. Since the reverse reaction cannot increase further, neither can the forward reaction. Consistent with this prediction, two variants with additional amino acid substitutions showed 2-fold higher k{sub cat}, but K{sub m} also increased so the specificity constant, k{sub cat}/K{sub m}, remained similar. Third, how does the L29P substitution change the esterase activity? Ester hydrolysis decreased for most esters (75-fold for ethyl acetate) but not for methyl esters. In contrast, L29P PFE catalyzed hydrolysis of {var_epsilon}-caprolactone five times more efficiently than wild-type PFE. Molecular modeling suggests that moving the carbonyl group closer to the

  13. Genome sequence of the mycorrhizal helper bacterium Pseudomonas fluorescens BBc6R8

    Energy Technology Data Exchange (ETDEWEB)

    Deveau, Aurelie [French National Insitute for Agricultural Research (INRA); Grob, Harald [University of Bonn, Germany; Morin, Emmanuelle [INRA, Nancy, France; Karpinets, Tatiana V [ORNL; Utturkar, Sagar M [ORNL; Mehnaz, Samina [University of the Punjab, Pakistan; Kurz, Sven [University of Bonn, Germany; Martin, Francis [INRA, Nancy, France; Frey-Klett, Pascale [INRA, Nancy, France; Labbe, Jessy L [ORNL

    2014-01-01

    We report the draft genome sequence of the mycorrhiza helper bacterium Pseudomonas fluorescens strain BBc6R8 . Several traits which could be involved in the mycorrhiza helper ability of the bacterial strain such as multiple secretion systems, auxin metabolism and phosphate mobilization were evidenced in the genome.

  14. Sensitivity of Pseudomonas fluorescens to gamma irradiation following surface inoculations on romaine lettuce and baby spinach

    Science.gov (United States)

    Irradiation of fresh fruits and vegetables is a post-harvest intervention measure often used to inactivate pathogenic food-borne microbes. We evaluated the sensitivity of Pseudomonas fluorescens strains (2-79, Q8R1, Q287) to gamma irradiation following surface inoculations on romaine lettuce and spi...

  15. Water flow induced transport of Pseudomonas fluorescens cells through soil columns as affected by inoculant treatment

    NARCIS (Netherlands)

    Hekman, W.E.; Heijnen, C.E.; Trevors, J.T.; Elsas, van J.D.

    1994-01-01

    Water flow induced transport of Pseudomonas fluorescens cells through soil columns was measured as affected by the inoculant treatment. Bacterial cells were introduced into the topsoil of columns, either encapsulated in alginate beads of different types or mixed with bentonite clay in concentrations

  16. Improved Performance of Pseudomonas fluorescens lipase by covalent immobilization onto Amberzyme

    NARCIS (Netherlands)

    Aslan, Yakup; Handayani, Nurrahmi; Stavila, Erythrina; Loos, Katja

    2013-01-01

    Objective: In this study, the conditions of covalent immobilization of Pseudomonas fluorescens lipase onto an oxirane-activated support (Amberzyme) were optimized to obtain a high activity yield. Furthermore, the operational and storage stabilities of immobilized lipase were tested. Methods: Optimum

  17. Evolutionary history of the phl gene cluster in the plant-associated bacterium Pseudomonas fluorescens

    NARCIS (Netherlands)

    Moynihan, J.A.; Morrissey, J.P.; Coppoolse, E.; Stiekema, W.J.; O'Gara, F.; Boyd, E.F.

    2009-01-01

    Pseudomonas fluorescens is of agricultural and economic importance as a biological control agent largely because of its plant-association and production of secondary metabolites, in particular 2, 4-diacetylphloroglucinol (2, 4-DAPG). This polyketide, which is encoded by the eight gene phl cluster,

  18. Iron-regulated metabolites of plant growth-promoting Pseudomonas fluorescens WCS374 : Their role in induced systemic resistance

    NARCIS (Netherlands)

    Djavaheri, M.

    2007-01-01

    The plant growth-promoting rhizobacterium Pseudomonas fluorescens WCS374r effectively suppresses fusarium wilt in radish by induced systemic resistance (ISR). In radish, WCS374r-mediated ISR depends partly on iron-regulated metabolites. Under iron-limiting conditions, P. fluorescens WCS374r produces

  19. The structure-function relationship of WspR, a Pseudomonas fluorescens response regulator with a GGDEF output domain

    National Research Council Canada - National Science Library

    Malone, J. G; Williams, R; Christen, M; Jenal, U; Spiers, A. J; Rainey, P. B

    2007-01-01

    ...{at}auckland.ac.nz The GGDEF response regulator WspR couples the chemosensory Wsp pathway to the overproduction of acetylated cellulose and cell attachment in the Pseudomonas fluorescens SBW25 wrinkly spreader (WS) genotype...

  20. HETEROLOGOUS EXPRESSION OF A CHITINASE GENE FROM AEROMONAS CAVIAEIN PSEUDOMONAS FLUORESCENS

    Directory of Open Access Journals (Sweden)

    ANTONIUS SUWANTO

    2003-01-01

    Full Text Available A transcriptional fusion for an Aeromonas caviae chitinase gene was constructed under the control of a constitutive promoter of the kanaraycin resistance gene (PKmR. The construct was inserted into a medium copy number broad host range plasmid vector to yield recombinant plasmid pAM340, which harbored transcriptional fusion PKmR- chi. Another transcriptional fusion, Ptac-chi, in a recombinant plasmid pAM630, was conducted as comparison. Triparental mating of E. coli carrying the recombinant plasmids with Pseudomotws fluorescens 5100, a phyllosphere bacterium, was performed. Pseudomonas fluorescens 5100 exconjugants were examined for constitutive expression of chitinase employing a spectrophotometric assay; they showed stronger chitin degradation activity than Escherichia coli transformants. Using a fungal antagonism plate assay, this chitinolytic P. fluorescens, however, could not inhibit selected phytopathogenic fungi.

  1. Lack of AHL-based quorum sensing in Pseudomonas fluorescens isolated from milk

    Science.gov (United States)

    Martins, Maurilio L.; Pinto, Uelinton M.; Riedel, Kathrin; Vanetti, Maria C.D.; Mantovani, Hilário C.; de Araújo, Elza F.

    2014-01-01

    Numerous bacteria coordinate gene expression in response to small signalling molecules in many cases known as acylhomoserine lactones (AHLs), which accumulate as a function of cell density in a process known as quorum sensing. This work aimed to determine if phenotypes that are important to define microbial activity in foods such as biofilm formation, swarming motility and proteolytic activity of two Pseudomonas fluorescens strains, isolated from refrigerated raw milk, are influenced by AHL molecules. The tested P. fluorescens strains did not produce AHL molecules in none of the evaluated media. We found that biofilm formation was dependent on the culture media, but it was not influenced by AHLs. Our results indicate that biofilm formation, swarming motility and proteolytic activity of the tested P. fluorescens strains are not regulated by acyl-homoserine lactones. It is likely that AHL-dependent quorum sensing system is absent from these strains. PMID:25477941

  2. Systematic investigations on the biodegradation and viscosity reduction of long chain hydrocarbons using Pseudomonas aeruginosa and Pseudomonas fluorescens.

    Science.gov (United States)

    Sakthipriya, N; Doble, Mukesh; Sangwai, Jitendra S

    2016-03-01

    The use of microorganisms has been researched extensively for possible applications related to hydrocarbon degradation in the petroleum industry. However, attempts to improve the effect of microorganisms on the viscosity of hydrocarbons, which find potential use in the development of robust models for biodegradation, have been rarely documented. This study investigates the degradation of long chain hydrocarbons, such as hexadecane and eicosane using Pseudomonas fluorescens PMMD3 (P. fluorescens) and Pseudomonas aeruginosa CPCL (P. aeruginosa). P. aeruginosa used here is isolated from petroleum contaminated sediments and the P. fluorescens is from the coastal area, and both have hydrocarbon degrading genes. The degradation of hydrocarbons is studied using carbon profiling and reduction in viscosity pre- and post-degradation of hydrocarbons. The carbon profiling has been obtained using gas chromatography-mass spectroscopy (GC-MS), and Fourier transform infrared spectrometer (FTIR) results. GC-MS results have indicated an improved biodegradation of hydrocarbons by 77-93% in one day. The yield coefficients of biomass (YX/S) for P. aeruginosa and P. fluorescens using hexadecane as a carbon source are 1.35 and 0.81 g g(-1), and the corresponding values with eicosane are 0.84 and 0.88 g g(-1). The viscosity of hexadecane is reduced by the order of 53 and 47%, while that of eicosane was reduced by 53 and 65%, using P. aeruginosa and P. fluorescens, respectively. This study also presents information on the activity of enzymes responsible for the hydrocarbon degradation. Pseudomonas species have shown their use in potential applications for bioremediation, oil-spill treatment, and flow assurance. We believe that this study will also provide stringent tests for possible model development for the bioremediation of long chain paraffins suitable for oilfield applications.

  3. Pseudomine, an isoxazolidone with siderophoric activity from Pseudomonas fluorescens AH2 isolated from Lake Victorian Nile Perch

    DEFF Research Database (Denmark)

    Anthoni, U.; Christophersen, C.; Nielsen, P.H.

    1995-01-01

    A siderophore, pseudomonine, and sodium salicylate were isolated from the culture broth of iron-deficient cultures of Pseudomonas fluorescens AH2 isolated from the surface of spoiled Nile Perch from Lake Victoria......A siderophore, pseudomonine, and sodium salicylate were isolated from the culture broth of iron-deficient cultures of Pseudomonas fluorescens AH2 isolated from the surface of spoiled Nile Perch from Lake Victoria...

  4. Getting the ecology into interactions between plants and the plant growth-promoting bacterium Pseudomonas fluorescens.

    Science.gov (United States)

    Hol, W H Gera; Bezemer, T Martijn; Biere, Arjen

    2013-01-01

    Plant growth-promoting rhizobacteria (PGPR) are increasingly appreciated for their contributions to primary productivity through promotion of growth and triggering of induced systemic resistance in plants. Here we focus on the beneficial effects of one particular species of PGPR (Pseudomonas fluorescens) on plants through induced plant defense. This model organism has provided much understanding of the underlying molecular mechanisms of PGPR-induced plant defense. However, this knowledge can only be appreciated at full value once we know to what extent these mechanisms also occur under more realistic, species-diverse conditions as are occurring in the plant rhizosphere. To provide the necessary ecological context, we review the literature to compare the effect of P. fluorescens on induced plant defense when it is present as a single species or in combination with other soil dwelling species. Specifically, we discuss combinations with other plant mutualists (bacterial or fungal), plant pathogens (bacterial or fungal), bacterivores (nematode or protozoa), and decomposers. Synergistic interactions between P. fluorescens and other plant mutualists are much more commonly reported than antagonistic interactions. Recent developments have enabled screenings of P. fluorescens genomes for defense traits and this could help with selection of strains with likely positive interactions on biocontrol. However, studies that examine the effects of multiple herbivores, pathogens, or herbivores and pathogens together on the effectiveness of PGPR to induce plant defenses are underrepresented and we are not aware of any study that has examined interactions between P. fluorescens and bacterivores or decomposers. As co-occurring soil organisms can enhance but also reduce the effectiveness of PGPR, a better understanding of the biotic factors modulating P. fluorescens-plant interactions will improve the effectiveness of introducing P. fluorescens to enhance plant production and defense.

  5. Inhibition of quorum sensing-controlled virulence factors and biofilm formation in Pseudomonas fluorescens by cinnamaldehyde.

    Science.gov (United States)

    Li, Tingting; Wang, Dangfeng; Liu, Nan; Ma, Yan; Ding, Ting; Mei, Yongchao; Li, Jianrong

    2018-02-01

    Pseudomonas fluorescens, an important food spoiling bacteria, uses quorum sensing to control biofilm formation and motility. To date, only a few compounds targeting the LuxR-based quorum sensing system of P. fluorescens have been identified. In the present study, the quorum sensing inhibitory effect of cinnamaldehyde at sublethal concentrations was investigated in terms of inhibition of the extracellular protease, biofilm formation, and swimming and swarming motility. The total volatile basic nitrogen value was also measured to evaluate the effect of cinnamaldehyde on quality preservation of turbot fillets stored at 4 ± 1 °C for 15 days. The results showed that cinnamaldehyde significantly inhibited quorum sensing-dependent factors in P. fluorescens and extended the storage life of turbot. Unexpectedly, cinnamaldehyde did not interfere with production of AHLs (N-acylhomoserine lactones) by P. fluorescens, as shown by measurement of AHL production using GC-MS. Molecular docking analysis revealed that cinnamaldehyde can interact with the LuxR-type protein of P. fluorescens, which could constitute the molecular basis of the quorum sensing inhibition observed. These findings strongly suggest that cinnamaldehyde is a quorum sensing inhibitor with great potential for the preservation of aquatic products to guarantee food safety. Copyright © 2018. Published by Elsevier B.V.

  6. Aplikasi Formula Cair Pseudomonas fluorescens P60 untuk Menekan Penyakit Virus Cabai Merah

    Directory of Open Access Journals (Sweden)

    Loekas Soesanto

    2014-08-01

    Full Text Available Viral diseases of chilli pepper are difficult to control, therefore the use of Pseudomonas fluorescens P60 should be evaluated. The aims of this research were to determine the influence of liquid formula of P. fluorescens P60 on virod disease and on growth and yield of chili pepper. Randomized block design (RBD experiment was composed of 7 treatments and 4 replicates, i.e., control, insecticide applicaton, P. fluorescens P60 application by seedling drenching and spraying for 1, 2, 3, 5, and 7 times. The result showed that 5 times application of P. fluorescens P60 by drenching and spraying was able to suppress viral disease and reduce disease intensity by to 73.37%, increasing density level of P. fluorescens P60 to 9.50 x 1011 and increase phenolic compounds (saponin, tannin and glycoside. The same treatment could increase plant height 23.7%, root lenght 6.44%, plant dry weight 66.68%, root dry weight 23.59%, and yield weight 53.16%.

  7. Extensively drug-resistant Pseudomonas aeruginosa bacteremia in solid organ transplant recipients.

    Science.gov (United States)

    Bodro, Marta; Sabé, Núria; Tubau, Fe; Lladó, Laura; Baliellas, Carme; González-Costello, José; Cruzado, Josep Maria; Carratalà, Jordi

    2015-03-01

    We sought to determine the risk factors, molecular epidemiology, antibiotic therapy, and outcomes of bacteremia because of extensively drug-resistant (XDR) Pseudomonas aeruginosa in solid organ transplant (SOT) recipients. All episodes of bacteremia occurring in SOT recipients were prospectively documented from 2007 to 2013. Of 318 episodes of bacteremia, 49 were caused by P. aeruginosa. Thirty-one strains (63%) were XDR defined by nonsusceptibility to at least one agent in all but two or fewer antipseudomonal antimicrobial categories. Time from transplantation to bacteremia was shorter in XDR P. aeruginosa group comparing to other etiologies (median days 66 vs. 278; P=0.03). Factors independently associated with XDR P. aeruginosa bacteremia were prior transplantation, nosocomial acquisition, and septic shock at onset. XDR P. aeruginosa isolates belonged to a single clone (ST-175). Comparing to other etiologies, patients with bacteremia because of XDR P. aeruginosa more often received inadequate empirical antibiotic therapy. Persistence of bacteremia, shock, respiratory failure and intensive care unit admission were more frequent in patients with XDR P. aeruginosa. The overall case-fatality rate was higher among patients with XDR P. aeruginosa bacteremia than in the others (38% vs. 16%; P=0.009). Bacteremia because of XDR P. aeruginosa should be carefully considered when selecting empirical antibiotic therapy for hospitalized SOT recipients with prior transplantation presenting with septic shock.

  8. SANITATION PROCESS OPTIMALIZATION IN RELATION TO THE MICROBIAL BIOFILM OF PSEUDOMONAS FLUORESCENS

    Directory of Open Access Journals (Sweden)

    Vladimír Vietoris

    2012-02-01

    Full Text Available Biofilms have been of considerable interest in the context of food hygiene. Extracellular polymeric substances play an important role in the attachment and colonization of microorganisms to food-contact surfaces. If the microorganisms from food-contact surfaces are not completely removed, they may lead to biofilm formation and also increase the biotransfer potential. The experimental part was focused on the adhesion of bacterial cells under static conditions and testing the effectiveness of disinfectants on created biofilm. In laboratory conditions we prepared and formed the bacterial biofilms Pseudomonas fluorescens in the test surfaces of stainless steel. Over the 72 hours and the next 72 hours were observed numbers of adhesion bacterial cells of Pseudomonas fluorescens on solid surfaces of tested materials.

  9. Biosynthesis and regulation of cyclic lipopeptides in Pseudomonas fluorescens

    NARCIS (Netherlands)

    Bruijn, de I.

    2009-01-01

    Cyclic lipopeptides (CLPs) are surfactant and antibiotic metabolites produced by a variety of bacterial genera. For the genus Pseudomonas, many structurally different CLPs have been identified. CLPs play an important role in surface motility of Pseudomonas strains, but also in virulence and

  10. The cellodextrinase from Pseudomonas fluorescens subsp. cellulosa consists of multiple functional domains.

    OpenAIRE

    Ferreira, L M; Hazlewood, G P; Barker, P J; Gilbert, H J

    1991-01-01

    A genomic library of Pseudomonas fluorescens subsp. cellulosa DNA was constructed in pUC18 and Escherichia coli recombinants expressing 4-methylumbelliferyl beta-D-cellobioside-hydrolysing activity (MUCase) were isolated. Enzyme produced by MUCase-positive clones did not hydrolyse either cellobiose or cellotriose but converted cellotetraose into cellobiose and cleaved cellopentaose and cellohexaose, producing a mixture of cellobiose and cellotriose. There was no activity against CM-cellulose,...

  11. Cyanase-mediated utilization of cyanate in Pseudomonas fluorescens NCIB 11764.

    OpenAIRE

    Kunz, D. A.; Nagappan, O

    1989-01-01

    Pseudomonas fluorescens NCIB 11764 was capable of utilizing cyanate (OCN-) as a sole nitrogen source for growth. Crude cell extracts from cells grown on cyanate, but not on ammonium sulfate, were induced for an enzyme catalyzing cyanate conversion to ammonia. Enzymatic activity was shown to be bicarbonate dependent and specific for cyanate as a substrate, suggesting that cyanate utilization in this organism is facilitated by an enzyme resembling cyanase (cyanate amidohydrolase; EC 3.5.5.3), a...

  12. Adhesion of Pseudomonas fluorescens biofilms to glass, stainless steel and cellulose

    OpenAIRE

    Wan Dagang, W.R.Z.; Bowen, J.; O'Keeffe, J.; Robbins, P.T.; Zhang, Z.

    2016-01-01

    Objectives: \\ud The adhesion of colloidal probes of stainless steel, glass and cellulose to Pseudomonas fluorescens biofilms was examined using atomic force microscopy (AFM) to allow comparisons between surfaces to which biofilms might adhere.\\ud \\ud Results: \\ud Biofilm was grown on a stainless steel substrate and covered most of the surface after 96 h. AFM approach and retraction curves were obtained when the biofilm was immersed in a tryptone/soy medium. On approach, all the colloidal prob...

  13. A genetically engineered Pseudomonas fluorescens strain possesses the dual activity against phytopathogenic fungi and insects.

    Science.gov (United States)

    Lu, Wenwei; Zhang, Weiqiong; Bai, Yan; Fu, Yingying; Chen, Jun; Geng, Xiaolu; Wang, Yujing; Xiao, Ming

    2010-02-01

    A Pseudomonas fluorescens strain was isolated and showed antagonistic activity against phytopathogenic fungi and found to possess a gene responsible for production of antibiotic 2, 4-diacetylphloroglucinol. For the extension of biocontrol range, a gene for an Androctonus australis Hector insect toxin 1 (AaHIT1), one of the most toxic known insect-selective peptides, was designed and synthesized according to the preferred codon usage of Pseudomonas fluorescens, cloned and transformed into the strain by pSUP106 vector, a broad-host-range plasmid. Bioassays indicated that the engineered strain was able to produce AaHIT1 with insecticidal activity, in the same time retained the activity against plant pathogen. The experiments for nonplanted soil and rhizosphere colonization showed that, similar to the population of the wild-type strain, that of the engineered strain remained relatively constant in the first 10 d, and the subsequent 50 d, suggesting that AaHIT expression in the bacterial cell does not substantially impair its long-term colonization. It is first reported that a Pseudomonas fluorescens strain expressing an active scorpion neurotoxin has dual activity against phytopathogenic fungi and insects, attractive for agronomic applications.

  14. Initial characterization of a bolA homologue from Pseudomonas fluorescens indicates different roles for BolA-like proteins in em>P. fluorescens and Escherichia coli

    DEFF Research Database (Denmark)

    Koch, Birgit; Nybroe, Ole

    2006-01-01

    The RpoS-regulated bolA gene in Escherichia coli is important for the decrease in cell size during stationary phase or sudden carbon starvation. A Pseudomonas fluorescens strain mutated in a gene with homology to bolA reduced its cell size upon carbon starvation, and RpoS had little effect on bol...

  15. Isolation and characterization of a T7-like lytic phage for Pseudomonas fluorescens

    Directory of Open Access Journals (Sweden)

    Neubauer Peter

    2008-10-01

    Full Text Available Abstract Background Despite the proven relevance of Pseudomonas fluorescens as a spoilage microorganism in milk, fresh meats and refrigerated food products and the recognized potential of bacteriophages as sanitation agents, so far no phages specific for P. fluorescens isolates from dairy industry have been closely characterized in view of their lytic efficiency. Here we describe the isolation and characterization of a lytic phage capable to infect a variety of P. fluorescens strains isolated from Portuguese and United States dairy industries. Results Several phages were isolated which showed a different host spectrum and efficiency of lysis. One of the phages, phage ϕIBB-PF7A, was studied in detail due to its efficient lysis of a wide spectrum of P. fluorescens strains and ribotypes. Phage ϕIBB-PF7A with a head diameter of about 63 nm and a tail size of about 13 × 8 nm belongs morphologically to the Podoviridae family and resembles a typical T7-like phage, as analyzed by transmission electron microscopy (TEM. The phage growth cycle with a detected latent period of 15 min, an eclipse period of 10 min, a burst size of 153 plaque forming units per infected cell, its genome size of approximately 42 kbp, and the size and N-terminal sequence of one of the protein bands, which gave similarity to the major capsid protein 10A, are consistent with this classification. Conclusion The isolated T7-like phage, phage ϕIBB-PF7A, is fast and efficient in lysing different P. fluorescens strains and may be a good candidate to be used as a sanitation agent to control the prevalence of spoilage causing P. fluorescens strains in dairy and food related environments.

  16. Genome-wide analysis of bacterial determinants of plant growth promotion and induced systemic resistance by Pseudomonas fluorescens

    NARCIS (Netherlands)

    Cheng, Xu; Etalo, Desalegn W.; van de Mortel, Judith E.; Dekkers, Ester; Nguyen, Linh; Medema, Marnix H; Raaijmakers, Jos M.

    2017-01-01

    Pseudomonas fluorescens strain SS101 (Pf.SS101) promotes growth of Arabidopsis thaliana, enhances greening and lateral root formation, and induces systemic resistance (ISR) against the bacterial pathogen Pseudomonas syringae pv. tomato (Pst). Here, targeted and untargeted approaches were adopted to

  17. Production and properties of biosurfactants from a newly isolated Pseudomonas fluorescens HW-6 growing on hexandecane

    Energy Technology Data Exchange (ETDEWEB)

    Vasileva-Tonkova, E.; Galabova, D. [Bulgarian Academy of Sciences, Dept. of Microbial Biochemistry, Sofia (Bulgaria); Stoimenova, E.; Lalchev, Z. [Dept. of Biochemistry, Sofia Univ. ' ' St. Kliment Ohridski' ' , Sofia (Bulgaria)

    2006-07-15

    The newly isolated from industrial wastewater Pseudomonas fluorescens strain HW-6 produced glycolipid biosurfactants at high concentrations (1.4-2.0 g 1{sup -1}) when grown on hexadecane as a sole carbon source. Biosurfactants decreased the surface tension of the air/water interface by 35 mN m{sup -1} and possessed a low critical micelle concentration value of 20 mg 1{sup -1}, which indicated high surface activity. They efficiently emulsified aromatic hydrocarbons, kerosene, n-paraffins and mineral oils. Biosurfactant production contributed to a significant increase in cell hydrophobicity correlated with an increased growth of the strain on hexadecane. The results suggested that the newly isolated strain of Ps. fluorescens and produced glycolipid biosurfactants with effective surface and emulsifying properties are very promising and could find application for bioremediation of hydrocarbon-polluted sites. (orig.)

  18. Analysis of Bacillus thuringiensis Population Dynamics and Its Interaction With Pseudomonas fluorescens in Soil

    Science.gov (United States)

    Rojas-Ruiz, Norma Elena; Sansinenea-Royano, Estibaliz; Cedillo-Ramirez, Maria Lilia; Marsch-Moreno, Rodolfo; Sanchez-Alonso, Patricia; Vazquez-Cruz, Candelario

    2015-01-01

    Background: Bacillus thuringiensis is the most successful biological control agent, however, studies so far have shown that B. thuringiensis is very sensitive to environmental factors such as soil moisture and pH. Ultraviolet light from the sun had been considered as the main limiting factor for its persistence in soil and it has recently been shown that the antagonism exerted by other native soil organisms, such as Pseudomonas fluorescens, is a determining factor in the persistence of this bacterium under in vitro culture conditions. Objectives: The aim of the present investigation was to analyze the population dynamics of B. thuringiensis and its interaction with P. fluorescens using microbiological and molecular methods in soil, under different conditions, and to determinate the effect of nutrients and moisture on its interaction. Materials and Methods: The monitoring was performed by microbiological methods, such as viable count of bacteria, and molecular methods such as Polymerase Chain Reaction (PCR) and hybridization, using the direct extraction of DNA from populations of inoculated soil. Results: The analysis of the interaction between B. thuringiensis and P. fluorescens in soil indicated that the disappearance of B. thuringiensis IPS82 is not dependent on the moisture but the composition of nutrients that may be affecting the secretion of toxic compounds in the environment of P. fluorescens. The results showed that the recovered cells were mostly spores and not vegetative cells in all proved treatments. The molecular methods were effective for monitoring bacterial population inoculated in soil. Conclusions: Bacillus thuringiensis is very sensitive to the interaction of P. fluorescens, however is capable to survive in soil due to its capacity of sporulate. Some of the cells in the form of spores germinated and folded slightly and remained in a constant cycle of sporulation and germination. This confirms that B. thuringiensis IPS82 can germinate, grow and

  19. Analysis of Bacillus thuringiensis Population Dynamics and Its Interaction With Pseudomonas fluorescens in Soil.

    Science.gov (United States)

    Rojas-Ruiz, Norma Elena; Sansinenea-Royano, Estibaliz; Cedillo-Ramirez, Maria Lilia; Marsch-Moreno, Rodolfo; Sanchez-Alonso, Patricia; Vazquez-Cruz, Candelario

    2015-09-01

    Bacillus thuringiensis is the most successful biological control agent, however, studies so far have shown that B. thuringiensis is very sensitive to environmental factors such as soil moisture and pH. Ultraviolet light from the sun had been considered as the main limiting factor for its persistence in soil and it has recently been shown that the antagonism exerted by other native soil organisms, such as Pseudomonas fluorescens, is a determining factor in the persistence of this bacterium under in vitro culture conditions. The aim of the present investigation was to analyze the population dynamics of B. thuringiensis and its interaction with P. fluorescens using microbiological and molecular methods in soil, under different conditions, and to determinate the effect of nutrients and moisture on its interaction. The monitoring was performed by microbiological methods, such as viable count of bacteria, and molecular methods such as Polymerase Chain Reaction (PCR) and hybridization, using the direct extraction of DNA from populations of inoculated soil. The analysis of the interaction between B. thuringiensis and P. fluorescens in soil indicated that the disappearance of B. thuringiensis IPS82 is not dependent on the moisture but the composition of nutrients that may be affecting the secretion of toxic compounds in the environment of P. fluorescens. The results showed that the recovered cells were mostly spores and not vegetative cells in all proved treatments. The molecular methods were effective for monitoring bacterial population inoculated in soil. Bacillus thuringiensis is very sensitive to the interaction of P. fluorescens, however is capable to survive in soil due to its capacity of sporulate. Some of the cells in the form of spores germinated and folded slightly and remained in a constant cycle of sporulation and germination. This confirms that B. thuringiensis IPS82 can germinate, grow and sporulate in soil.

  20. Genetic Control of Plant Root Colonization by the Biocontrol agent, Pseudomonas fluorescens

    Energy Technology Data Exchange (ETDEWEB)

    Cole, Benjamin J.; Fletcher, Meghan; Waters, Jordan; Wetmore, Kelly; Blow, Matthew J.; Deutschbauer, Adam M.; Dangl, Jeffry L.; Visel, Axel

    2015-03-19

    Plant growth promoting rhizobacteria (PGPR) are a critical component of plant root ecosystems. PGPR promote plant growth by solubilizing inaccessible minerals, suppressing pathogenic microorganisms in the soil, and directly stimulating growth through hormone synthesis. Pseudomonas fluorescens is a well-established PGPR isolated from wheat roots that can also colonize the root system of the model plant, Arabidopsis thaliana. We have created barcoded transposon insertion mutant libraries suitable for genome-wide transposon-mediated mutagenesis followed by sequencing (TnSeq). These libraries consist of over 105 independent insertions, collectively providing loss-of-function mutants for nearly all genes in the P.fluorescens genome. Each insertion mutant can be unambiguously identified by a randomized 20 nucleotide sequence (barcode) engineered into the transposon sequence. We used these libraries in a gnotobiotic assay to examine the colonization ability of P.fluorescens on A.thaliana roots. Taking advantage of the ability to distinguish individual colonization events using barcode sequences, we assessed the timing and microbial concentration dependence of colonization of the rhizoplane niche. These data provide direct insight into the dynamics of plant root colonization in an in vivo system and define baseline parameters for the systematic identification of the bacterial genes and molecular pathways using TnSeq assays. Having determined parameters that facilitate potential colonization of roots by thousands of independent insertion mutants in a single assay, we are currently establishing a genome-wide functional map of genes required for root colonization in P.fluorescens. Importantly, the approach developed and optimized here for P.fluorescens>A.thaliana colonization will be applicable to a wide range of plant-microbe interactions, including biofuel feedstock plants and microbes known or hypothesized to impact on biofuel-relevant traits including biomass productivity

  1. Supervivencia de Pseudomonas fluorescens en suelos con diferente contenido de materia orgánica Pseudomonas fluorescens survival in soils with different contents of organic matter

    Directory of Open Access Journals (Sweden)

    E.B.R. Perotti

    2005-06-01

    Full Text Available Pseudomonas fluorescens es una bacteria PGPR (plant growth promoting rhizobacteria, heterótrofa, capaz de combatir fitopatógenos edáficos. Su supervivencia podría estar favorecida por el elevado contenido de materia orgánica del suelo (MOS. Para probarlo, se inocularon, en condiciones de laboratorio, tres cepas de P. fluorescens: UP61, C7R12, y P190 (nativa de Balcarce, Buenos Aires en suelos rizosféricos de tomate representativos de diferentes zonas de Argentina: suelo Argiudol (Balcarce, y Zavalla, Santa Fe y suelo Torrifluvens (Cipolletti, Río Negro (MOS %: 7,2; 4,3 y 2,6 respectivamente. Los resultados indicaron que la supervivencia de P. fluorescens en los suelos Argiudoles fue similar; aunque las pendientes de las curvas de supervivencia en el suelo de Zavalla fueron menores que las observadas en el suelo de Balcarce. La producción de CO2 fue superior en el suelo de Balcarce que en el suelo de Zavalla (4,3 y 2,8 mmol.g-1suelo, esta diferencia podría ser explicada por la existencia de una mayor presión competitiva por parte de la microflora nativa. La supervivencia en el suelo Torrifluvens resultó mínima, lo que sería atribuible a su elevada conductividad eléctrica más que al menor contenido de MOS. La cepa UP61 presentó en todos los casos la mejor supervivencia.Pseudomonas fluorescens are plant growth promoting rhizobacteria (PGPR. The survival of this inoculated heterotrophic bacterium may be affected by soil organic matter content (SOM. To confirm this hypothesis, three strains of P. fluorescens: UP61, C7R12 y P190 (native of Balcarce, Buenos Aires were inoculated, in laboratory conditions, into three argentine rhizospheric soils: two Argiudolls (Balcarce, and Zavalla, Santa Fe and a Torrifluvens (Cipolletti, Río Negro with different SOM: 7,2; 4,3; and 2,6%, respectibily. The results indicated that the all three isolates survival in general was not different. The slopes of the regression curves in Zavalla soil were very

  2. Cyanase-mediated utilization of cyanate in Pseudomonas fluorescens NCIB 11764.

    Science.gov (United States)

    Kunz, D A; Nagappan, O

    1989-01-01

    Pseudomonas fluorescens NCIB 11764 was capable of utilizing cyanate (OCN-) as a sole nitrogen source for growth. Crude cell extracts from cells grown on cyanate, but not on ammonium sulfate, were induced for an enzyme catalyzing cyanate conversion to ammonia. Enzymatic activity was shown to be bicarbonate dependent and specific for cyanate as a substrate, suggesting that cyanate utilization in this organism is facilitated by an enzyme resembling cyanase (cyanate amidohydrolase; EC 3.5.5.3), as described previously in Escherichia coli and Flavobacterium sp.

  3. The Influence of Pseudomonas fluorescens on Corrosion Products of Archaeological Tin-Bronze Analogues

    Science.gov (United States)

    Ghiara, G.; Grande, C.; Ferrando, S.; Piccardo, P.

    2018-01-01

    In this study, tin-bronze analogues of archaeological objects were investigated in the presence of an aerobic Pseudomonas fluorescens strain in a solution, containing chlorides, sulfates, carbonates and nitrates according to a previous archaeological characterization. Classical fixation protocols were employed in order to verify the attachment capacity of such bacteria. In addition, classical metallurgical analytical techniques were used to detect the effect of bacteria on the formation of uncommon corrosion products in such an environment. Results indicate quite a good attachment capacity of the bacteria to the metallic surface and the formation of the uncommon corrosion products sulfates and sulfides is probably connected to the bacterial metabolism.

  4. Exposure-related effects of Pseudomonas fluorescens (Pf-CL145A) on juvenile unionid mussels

    Science.gov (United States)

    Weber, Kerry L.; Luoma, James A.; Mayer, Denise A.; Aloisi, Douglas B.; Eckert, Nathan L.

    2015-01-01

    The exposure-related effects of a commercially prepared spray-dried powder (SDP) or freeze-dried powder (FDP) formulation of Pseudomonas fluorescens (strain CL145A) on the survival of seven species of newly metamorphosed (randomly distributed to test chambers and each species independently exposed for 24 hours to a static dose of either SDP (four species: Lampsilis cardium, Lampsilis siliquoidea, Lampsilis higginsii, andLigumia recta) or FDP (three species: Obovaria olivaria, Actinonaias ligamentina, andMegalonaias nervosa).

  5. The combined effects of Pseudomonas fluorescens and Tuber melanosporum on the quality of Pinus halepensis seedlings.

    Science.gov (United States)

    Dominguez, J A; Martin, A; Anriquez, A; Albanesi, A

    2012-08-01

    The ecological, economic and social values of the ectomycorrhizal fungi of the black truffle found in the rural Mediterranean are well known. The inoculation of Pinus halepensis seedlings with mycorrhizal fungi and rhizobacteria can improve the morphology and physiology of the seedlings and benefit the regeneration of arid regions and the reintroduction of inocula of mycorrhizal fungi into these areas. Some rhizobacteria can improve the establishment and functioning of ectomycorrhizal symbiosis. In this study, seedlings of P. halepensis were inoculated with the mycorrhizal fungus Tuber melanosporum and the rhizobacteria Pseudomonas fluorescens CECT 844 under non-limiting greenhouse conditions. Five months after inoculation, we analysed the growth, water parameters (osmotic potential at saturation, osmotic potential at turgor loss and modulus of elasticity), concentrations of mycorrhizal colonies, nutrient concentration and nutrient contents (N, P, K, Ca, Mg and Fe) in roots and aerial parts of the seedlings. Subsequently, tests were performed to estimate the root growth potentials. None of the treatments changed the water parameters or growth potentials of the roots. The inoculations improved the growth and nutrient uptake of the seedlings, although the combination of P. fluorescens CECT 844 and T. melanosporum did not generally lead to a significant improvement over the positive effects of a simple inoculation of T. melanosporum; however, the addition of P. fluorescens CECT 844 did double the rate of the mycorrhization of T. melanosporum. These results may be promising for enhancing the cultivation of truffles.

  6. Growth of Amanita caesarea in the presence of Pseudomonas fluorescens and Bacillus cereus.

    Science.gov (United States)

    Cano, J M; Berrocal-Lobo, M; Domínguez-Núñez, J A

    2017-09-01

    The ectomycorrhizal (ECM) fungus Amanita caesarea CECT 20127 was tested in vitro with two potentially mycorrhizal-promoting bacterial strains, Pseudomonas fluorescens CECT 844 and Bacillus cereus CECT 148. Although P. fluorescens showed spatial and temporal compatibility with A. caesarea, it did not affect growth of the fungus. Conversely, B. cereus exhibited no such compatibility and also inhibited fungal growth. The expression pattern of the A. caesarea gene AcMST-1 was analysed using real-time quantitative polymerase chain reaction (qPCR) at three time points. This gene displays a high degree of homology with two genes, possible orthologues to AcMST-1, previously described in Amanita muscaria (AmMST-1) and Laccaria bicolor (LbMST-1) and encoding monosaccharide transporter proteins. The transcription levels of AcMST1 increased shortly after initial contact between A. caesarea and B. cereus, but expression of the gene was inhibited in the presence of P. fluorescens. Our results show that A. caesarea may possess orthologous genes of similar ECM fungal species that would allow it to adapt in nature to optimize sugar uptake from the environment depending on the presence of different microorganisms. Copyright © 2017 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  7. Impact of a Recombinant Biocontrol Bacterium, Pseudomonas fluorescens pc78, on Microbial Community in Tomato Rhizosphere.

    Science.gov (United States)

    Kong, Hyun Gi; Kim, Nam Hee; Lee, Seung Yeup; Lee, Seon-Woo

    2016-04-01

    Pseudomonas fluorescens pc78 is an effective biocontrol agent for soil-borne fungal diseases. We previously constructed a P43-gfp tagged biocontrol bacteria P. fluorescens pc78-48 to investigate bacterial traits in natural ecosystem and the environmental risk of genetically modified biocontrol bacteria in tomato rhizosphere. Fluctuation of culturable bacteria profile, microbial community structure, and potential horizontal gene transfer was investigated over time after the bacteria treatment to the tomato rhizosphere. Tagged gene transfer to other organisms such as tomato plants and bacteria cultured on various media was examined by polymerase chain reaction, using gene specific primers. Transfer of chromosomally integrated P43-gfp from pc78 to other organisms was not apparent. Population and colony types of culturable bacteria were not significantly affected by the introduction of P. fluorescens pc78 or pc78-48 into tomato rhizosphere. Additionally, terminal restriction fragment length polymorphism profiles were investigated to estimate the influence on the microbial community structure in tomato rhizosphere between non-treated and pc78-48-treated samples. Interestingly, rhizosphere soil treated with strain pc78-48 exhibited a significantly different bacterial community structure compared to that of non-treated rhizosphere soil. Our results suggest that biocontrol bacteria treatment influences microbial community in tomato rhizosphere, while the chromosomally modified biocontrol bacteria may not pose any specific environmental risk in terms of gene transfer.

  8. Metabolic functions of Pseudomonas fluorescens strains from Populus deltoides depend on rhizosphere or endosphere isolation compartment.

    Science.gov (United States)

    Timm, Collin M; Campbell, Alisha G; Utturkar, Sagar M; Jun, Se-Ran; Parales, Rebecca E; Tan, Watumesa A; Robeson, Michael S; Lu, Tse-Yuan S; Jawdy, Sara; Brown, Steven D; Ussery, David W; Schadt, Christopher W; Tuskan, Gerald A; Doktycz, Mitchel J; Weston, David J; Pelletier, Dale A

    2015-01-01

    The bacterial microbiota of plants is diverse, with 1000s of operational taxonomic units (OTUs) associated with any individual plant. In this work, we used phenotypic analysis, comparative genomics, and metabolic models to investigate the differences between 19 sequenced Pseudomonas fluorescens strains. These isolates represent a single OTU and were collected from the rhizosphere and endosphere of Populus deltoides. While no traits were exclusive to either endosphere or rhizosphere P. fluorescens isolates, multiple pathways relevant for plant-bacterial interactions are enriched in endosphere isolate genomes. Further, growth phenotypes such as phosphate solubilization, protease activity, denitrification and root growth promotion are biased toward endosphere isolates. Endosphere isolates have significantly more metabolic pathways for plant signaling compounds and an increased metabolic range that includes utilization of energy rich nucleotides and sugars, consistent with endosphere colonization. Rhizosphere P. fluorescens have fewer pathways representative of plant-bacterial interactions but show metabolic bias toward chemical substrates often found in root exudates. This work reveals the diverse functions that may contribute to colonization of the endosphere by bacteria and are enriched among closely related isolates.

  9. Metabolic functions of Pseudomonas fluorescens strains from Populus deltoides depend on rhizosphere or endosphere isolation compartment

    Directory of Open Access Journals (Sweden)

    Collin M Timm

    2015-10-01

    Full Text Available The bacterial microbiota of plants is diverse, with 1,000s of operational taxonomic units (OTUs associated with any individual plant. In this work we investigate the differences between 19 sequenced Pseudomonas fluorescens strains, isolated from Populus deltoides rhizosphere and endosphere and which represent a single OTU, using phenotypic analysis, comparative genomics, and metabolic models. While no traits were exclusive to either endosphere or rhizosphere P. fluorescens isolates, multiple pathways relevant for plant-bacterial interactions are enriched in endosphere isolate genomes. Further, growth phenotypes such as phosphate solubilization, protease activity, denitrification and root growth promotion are biased towards endosphere isolates. Endosphere isolates have significantly more metabolic pathways for plant signaling compounds and an increased metabolic range that includes utilization of energy rich nucleotides and sugars, consistent with endosphere colonization. Rhizosphere P. fluorescens have fewer pathways representative of plant-bacterial interactions but show metabolic bias towards chemical substrates often found in root exudates. This work reveals the diverse functions that may contribute to colonization of the endosphere by bacteria and are enriched among closely related isolates.

  10. Rhizobacteria Pseudomonas fluorescens and Azospirillum sp. association enhances growth of Lactuca sativa L. under tropical conditions

    Directory of Open Access Journals (Sweden)

    Amael APONTE

    2017-06-01

    Full Text Available The selection of microorganisms that enhance plant growth and confer biotic and abiotic tolerance to crops constitutes a biotechnology currently gaining importance on a global scale. The aim of this investigation was to evaluate the effects of inoculating rhizobacteria to lettuce (Lactuca sativa L. on seed germination and vegetative development in order to use isolates as potential biofertilizers under tropical conditions. Five isolates of Pseudomonas fluorescens (Pf and one of Azospirillum sp. (Az were inoculated to seeds using a bacterial suspension of 1.5*108 CFU*mL-1. In vitro, none of the isolates promoted germination. In vivo, isolates promoted growth and acted as stress alleviators by conferring tolerance to high temperatures (≥ 30 °C. The highest seedling emergence percentages were induced by the association of P.fluorescens with Azospirillum. This association also promoted the highest leaf-area in 25 d seedlings and exhibited a significantly higher dry-weight in 40 d plants compared to the control (P≤0.05 supporting the advantages of bio-consortiums over individual strains. The strains were able to produce dependent L-tryptophan indole-3-acetic acid (IAA, to solubilize phosphorous in vitro and tolerated at least 5%-salt stress. The results indicate that isolate Pf (26 and Az possess plant growth promoting rhizobacteria (PGPR traits and should be further assessed. This study suggests that P. fluorescens and Azospirillum act synergically and are able to trigger an induced-tolerance mechanism in lettuce under abiotic stress.

  11. Nonribosomal peptides, key biocontrol components for Pseudomonas fluorescens In5, isolated from a Greenlandic suppressive soil.

    Science.gov (United States)

    Michelsen, Charlotte F; Watrous, Jeramie; Glaring, Mikkel A; Kersten, Roland; Koyama, Nobuhiro; Dorrestein, Pieter C; Stougaard, Peter

    2015-03-17

    Potatoes are cultivated in southwest Greenland without the use of pesticides and with limited crop rotation. Despite the fact that plant-pathogenic fungi are present, no severe-disease outbreaks have yet been observed. In this report, we document that a potato soil at Inneruulalik in southern Greenland is suppressive against Rhizoctonia solani Ag3 and uncover the suppressive antifungal mechanism of a highly potent biocontrol bacterium, Pseudomonas fluorescens In5, isolated from the suppressive potato soil. A combination of molecular genetics, genomics, and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) imaging mass spectrometry (IMS) revealed an antifungal genomic island in P. fluorescens In5 encoding two nonribosomal peptides, nunamycin and nunapeptin, which are key components for the biocontrol activity by strain In5 in vitro and in soil microcosm experiments. Furthermore, complex microbial behaviors were highlighted. Whereas nunamycin was demonstrated to inhibit the mycelial growth of R. solani Ag3, but not that of Pythium aphanidermatum, nunapeptin instead inhibited P. aphanidermatum but not R. solani Ag3. Moreover, the synthesis of nunamycin by P. fluorescens In5 was inhibited in the presence of P. aphanidermatum. Further characterization of the two peptides revealed nunamycin to be a monochlorinated 9-amino-acid cyclic lipopeptide with similarity to members of the syringomycin group, whereas nunapeptin was a 22-amino-acid cyclic lipopeptide with similarity to corpeptin and syringopeptin. Crop rotation and systematic pest management are used to only a limited extent in Greenlandic potato farming. Nonetheless, although plant-pathogenic fungi are present in the soil, the farmers do not experience major plant disease outbreaks. Here, we show that a Greenlandic potato soil is suppressive against Rhizoctonia solani, and we unravel the key biocontrol components for Pseudomonas fluorescens In5, one of the potent biocontrol bacteria

  12. Lethality and developmental delay in Drosophila melanogaster larvae after ingestion of selected Pseudomonas fluorescens strains.

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    Marika H Olcott

    2010-09-01

    Full Text Available The fruit fly, Drosophila melanogaster, is a well-established model organism for probing the molecular and cellular basis of physiological and immune system responses of adults or late stage larvae to bacterial challenge. However, very little is known about the consequences of bacterial infections that occur in earlier stages of development. We have infected mid-second instar larvae with strains of Pseudomonas fluorescens to determine how infection alters the ability of larvae to survive and complete development.We mimicked natural routes of infection using a non-invasive feeding procedure to study the toxicity of the three sequenced P. fluorescens strains (Pf0-1, SBW25, and Pf-5 to Drosophila melanogaster. Larvae fed with the three strains of P. fluorescens showed distinct differences in developmental trajectory and survival. Treatment with SBW25 caused a subset of insects to die concomitant with a systemic melanization reaction at larval, pupal or adult stages. Larvae fed with Pf-5 died in a dose-dependent manner with adult survivors showing eye and wing morphological defects. In addition, larvae in the Pf-5 treatment groups showed a dose-dependent delay in the onset of metamorphosis relative to control-, Pf0-1-, and SBW25-treated larvae. A functional gacA gene is required for the toxic properties of wild-type Pf-5 bacteria.These experiments are the first to demonstrate that ingestion of P. fluorescens bacteria by D. melanogaster larvae causes both lethal and non-lethal phenotypes, including delay in the onset of metamorphosis and morphological defects in surviving adult flies, which can be decoupled.

  13. Pseudomonas fluorescens pirates both ferrioxamine and ferricoelichelin siderophores from Streptomyces ambofaciens.

    Science.gov (United States)

    Galet, Justine; Deveau, Aurélie; Hôtel, Laurence; Frey-Klett, Pascale; Leblond, Pierre; Aigle, Bertrand

    2015-05-01

    Iron is essential in many biological processes. However, its bioavailability is reduced in aerobic environments, such as soil. To overcome this limitation, microorganisms have developed different strategies, such as iron chelation by siderophores. Some bacteria have even gained the ability to detect and utilize xenosiderophores, i.e., siderophores produced by other organisms. We illustrate an example of such an interaction between two soil bacteria, Pseudomonas fluorescens strain BBc6R8 and Streptomyces ambofaciens ATCC 23877, which produce the siderophores pyoverdine and enantiopyochelin and the siderophores desferrioxamines B and E and coelichelin, respectively. During pairwise cultures on iron-limiting agar medium, no induction of siderophore synthesis by P. fluorescens BBc6R8 was observed in the presence of S. ambofaciens ATCC 23877. Cocultures with a Streptomyces mutant strain that produced either coelichelin or desferrioxamines, as well as culture in a medium supplemented with desferrioxamine B, resulted in the absence of pyoverdine production; however, culture with a double mutant deficient in desferrioxamines and coelichelin production did not. This strongly suggests that P. fluorescens BBbc6R8 utilizes the ferrioxamines and ferricoelichelin produced by S. ambofaciens as xenosiderophores and therefore no longer activates the production of its own siderophores. A screening of a library of P. fluorescens BBc6R8 mutants highlighted the involvement of the TonB-dependent receptor FoxA in this process: the expression of foxA and genes involved in the regulation of its biosynthesis was induced in the presence of S. ambofaciens. In a competitive environment, such as soil, siderophore piracy could well be one of the driving forces that determine the outcome of microbial competition. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  14. Characterization of the biocontrol activity of pseudomonas fluorescens strain X reveals novel genes regulated by glucose.

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    Gerasimos F Kremmydas

    Full Text Available Pseudomonas fluorescens strain X, a bacterial isolate from the rhizosphere of bean seedlings, has the ability to suppress damping-off caused by the oomycete Pythium ultimum. To determine the genes controlling the biocontrol activity of strain X, transposon mutagenesis, sequencing and complementation was performed. Results indicate that, biocontrol ability of this isolate is attributed to gcd gene encoding glucose dehydrogenase, genes encoding its co-enzyme pyrroloquinoline quinone (PQQ, and two genes (sup5 and sup6 which seem to be organized in a putative operon. This operon (named supX consists of five genes, one of which encodes a non-ribosomal peptide synthase. A unique binding site for a GntR-type transcriptional factor is localized upstream of the supX putative operon. Synteny comparison of the genes in supX revealed that they are common in the genus Pseudomonas, but with a low degree of similarity. supX shows high similarity only to the mangotoxin operon of Ps. syringae pv. syringae UMAF0158. Quantitative real-time PCR analysis indicated that transcription of supX is strongly reduced in the gcd and PQQ-minus mutants of Ps. fluorescens strain X. On the contrary, transcription of supX in the wild type is enhanced by glucose and transcription levels that appear to be higher during the stationary phase. Gcd, which uses PQQ as a cofactor, catalyses the oxidation of glucose to gluconic acid, which controls the activity of the GntR family of transcriptional factors. The genes in the supX putative operon have not been implicated before in the biocontrol of plant pathogens by pseudomonads. They are involved in the biosynthesis of an antimicrobial compound by Ps. fluorescens strain X and their transcription is controlled by glucose, possibly through the activity of a GntR-type transcriptional factor binding upstream of this putative operon.

  15. Predictive modeling of Pseudomonas fluorescens growth under different temperature and pH values

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    Letícia Dias dos Anjos Gonçalves

    Full Text Available Abstract Meat is one of the most perishable foods owing to its nutrient availability, high water activity, and pH around 5.6. These properties are highly conducive for microbial growth. Fresh meat, when exposed to oxygen, is subjected to the action of aerobic psychrotrophic, proteolytic, and lipolytic spoilage microorganisms, such as Pseudomonas spp. The spoilage results in the appearance of slime and off-flavor in food. In order to predict the growth of Pseudomonas fluorescens in fresh meat at different pH values, stored under refrigeration, and temperature abuse, microbial mathematical modeling was applied. The primary Baranyi and Roberts and the modified Gompertz models were fitted to the experimental data to obtain the growth parameters. The Ratkowsky extended model was used to determine the effect of pH and temperature on the growth parameter µmax. The program DMFit 3.0 was used for model adjustment and fitting. The experimental data showed good fit for both the models tested, and the primary and secondary models based on the Baranyi and Roberts models showed better validation. Thus, these models can be applied to predict the growth of P. fluorescens under the conditions tested.

  16. Survival of a Rifampicin-Resistant Pseudomonas fluorescens Strain in Nine Mollisols

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    Tami L. Stubbs

    2014-01-01

    Full Text Available Pseudomonas fluorescens strain D7 (P.f. D7 is a naturally occurring soil bacterium that shows promise as a biological herbicide to inhibit growth of annual grass weeds, including downy brome (Bromus tectorum L., in crop- and rangelands. Pseudomonas fluorescens strain D7rif (P.f. D7rif is a rifampicin-resistant strain of P.f. D7. One of the greatest obstacles to successful biological weed control is survival of the organism under field conditions. Nine soils in the taxonomic order of Mollisols, collected from downy brome-infested areas of the Western and Central United States, were inoculated with P.f. D7rif and incubated in the laboratory to determine the effects of soil type, soil properties, incubation temperature, and soil water potential on survival of P.f. D7rif over 63 days. Silt loam soils from Lind, Washington, and Moro, Oregon, sustained the highest P.f. D7rif populations, and recovery was the lowest from Pendleton, Oregon soil. Survival and recovery of P.f. D7rif varied with soil type and temperature but not with the two soil water potentials tested. After 63 days, P.f. D7rif was recovered at levels greater than log 5.5 colony forming units (CFU g−1 soil from five of the nine test soils, a level adequate to suppress downy brome under field or range conditions.

  17. Biocontrol of Rhizoctonia solani in native potato (Solanum phureja plants using native Pseudomonas fluorescens

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    Gloria Bautista

    2007-01-01

    Full Text Available Rhizoctonia solani is a soil borne phytopathogen associated with reduced plant vigor and tuber production in potato crops. There is a huge interest to search alternatives of biological control management of this disease, because the potato crops in Colombia are the highest consumers of chemical pesticides in Colombia. In order to obtain a fluorescent Pseudomonas strain with the capacity to reduce the disease symptoms produced by R. solani, determination and isolation of the predominant fluorescent Pseudomonas in several potato crops of the main Colombian producing region was done in a previous study. Six different P. fluorescens strains with none, moderate and high fungal growth inhibition capacity in vitro, were used in this study. Despite of the differences found in the dynamics of colonization and colonization capacity, all evaluated strains induced S. phureja growth and reduced disease symptoms produced by R. solani. Our results support the conclusion that association of P. fluorescens strains with S. phureja rhizosphere is a feasible alternative for the management of R. solani symptoms.

  18. Bioremediation of chromium contaminated soil by Pseudomonas fluorescens and indigenous microorganisms.

    Science.gov (United States)

    Jeyalakshmi, D; Kanmani, S

    2008-01-01

    Chromium is one of the toxic and hazardous pollutants in industrial wastewaters leading to soil contamination. In this study, the feasibility of remediating chromium contaminated soil using indigenous microorganisms and Pseudomonas fluorescens was evaluated. The contaminated soil sample was collected from Vellore and the pH, moisture content and chromium content were found to be 8.4, 22.5% and 5.1 mg/kg respectively. The effect of chromium on engineering properties showed decrease in permeability by 45.15%. For Pseudomonas fluorescens, the optimum pH, moisture content, biomass concentration and carbon source were found as 6.5, 20%, 10 mL and 10 mL/100 g respectively and for isolated mixed culture, the optimum parameters were found as 8.4, 25%, 15 mL and 15mL / 100 g respectively. Under optimum conditions, the reactor study showed 71.7% chromium reduction after 20 days. From the study, the bioremediation of chromium-contaminated soil by indigenous microorganisms was found to be a promising solution and after bioremediation, the engineering properties of the soil were found to be improved.

  19. Complete genome sequence of the lytic cold-active Pseudomonas fluorescens bacteriophage VSW-3 from Napahai plateau wetland.

    Science.gov (United States)

    Zhang, Chunjing; Zhang, Zhongyao; Li, Jiankai; Qin, Kunhao; Wei, Yunlin; Zhang, Qi; Lin, Lianbing; Ji, Xiuling

    2017-02-01

    The lytic cold-active bacteriophage VSW-3, belonging to the Podoviridae family and infecting the host Pseudomonas fluorescens SW-3, was isolated from the Napahai plateau wetland in China. With the development of sequencing technology, the study of Pseudomonas genomic diversity has increased; however, knowledge of cold-active phages infecting Pseudomonas is limited. The newly sequenced phage VSW-3 was classified based on virion morphology by transmission electron microscope. Sequence analysis revealed that the genome size was 40,556 bp with an overall GC content of 57.54 % and 46 open reading frames. The genome was organized into several modules containing genes for packaging, structural proteins, replication/transcription, and phage lysis. The sequence contained 45 potential promoters, 3 transcription terminators, and yet no tRNAs. This is the first report of cold-active Pseudomonas fluorescens bacteriophage genome sequencing.

  20. Draft Genome Sequence of the Polycyclic Aromatic Hydrocarbon-Degrading, Genetically Engineered Bioluminescent Bioreporter Pseudomonas fluorescens HK44

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Archana [ORNL; Layton, Alice [University of Tennessee, Knoxville (UTK); Williams, Daniel W [ORNL; Smart, Abby E. [University of Tennessee, Knoxville (UTK); Ripp, Steven Anthony [ORNL; Karpinets, Tatiana V [ORNL; Brown, Steven D [ORNL; Sayler, Gary Steven [ORNL

    2011-01-01

    Pseudomonas fluorescens strain HK44 (DSM 6700) is a genetically engineered lux-based bioluminescent bioreporter. Here we report the draft genome sequence of strain HK44. Annotation of {approx}6.1 Mb sequence indicates that 30% of the traits are unique and distributed over 5 genomic islands, a prophage and two plasmids.

  1. Wave-like distribution patterns of Gfp-marked Pseudomonas fluorescens along roots of wheat plants grown in two soils

    NARCIS (Netherlands)

    Bruggen, van A.H.C.; Semenov, A.M.; Zelenev, V.V.; Semenov, A.V.; Raaijmakers, J.M.; Sayler, R.J.; Vos, de O.J.

    2008-01-01

    Culturable rhizosphere bacterial communities had been shown to exhibit wave-like distribution patterns along wheat roots. In the current work we show, for the first time, significant wave-like oscillations of an individual bacterial strain, the biocontrol agent Pseudomonas fluorescens 32 marked with

  2. Draft Genome Sequence of the Polycyclic Aromatic Hydrocarbon-Degrading, Genetically Engineered Bioluminescent Bioreporter Pseudomonas fluorescens HK44 ▿

    Science.gov (United States)

    Chauhan, Archana; Layton, Alice C.; Williams, Daniel E.; Smartt, Abby E.; Ripp, Steven; Karpinets, Tatiana V.; Brown, Steven D.; Sayler, Gary S.

    2011-01-01

    Pseudomonas fluorescens strain HK44 (DSM 6700) is a genetically engineered lux-based bioluminescent bioreporter. Here we report the draft genome sequence of strain HK44. Annotation of ∼6.1 Mb of sequence indicates that 30% of the traits are unique and distributed over five genomic islands, a prophage, and two plasmids. PMID:21742869

  3. Assessment of DAPG-producing Pseudomonas fluorescens for management of Meloidogyne incognita and Fusarium oxysporum on watermelon

    Science.gov (United States)

    Pseudomonas fluorescens isolates Clinto 1R, Wayne 1R and Wood 1R, which produce the antibiotic 2,4-diacetylphloroglucinol (DAPG), can suppress soilborne diseases and promote plant growth. Consequently, these beneficial bacterial isolates were tested on watermelon plants for suppression of Meloidogy...

  4. Kinetic modelling of enzyme inactivation : kinetics of heat inactivation of the extracellular proteinase from Pseudomonas fluorescens 22F

    NARCIS (Netherlands)

    Schokker, E.P.

    1997-01-01

    The kinetics of heat inactivation of the extracellular proteinase from Pseudomonas fluorescens 22F was studied. It was established, by making use of kinetic modelling, that heat inactivation in the temperature range 35 - 70 °C was most likely caused

  5. Longitudinal nosocomial outbreak of Pseudomonas fluorescens bloodstream infection of 2 years' duration in a coronary care unit.

    Science.gov (United States)

    Oba, Yuichiro; Nakajima, Takahiro; Ogida, Chiyo; Kawanami, Miyuki; Fujiwara, Mamoru; Matsumura, Ikuko

    2017-08-01

    Outbreaks of bloodstream infections (BSI) of nonfermenting bacteria are a critical issue and often associated with hospital environments. We experienced a long-lasting outbreak of Pseudomonas fluorescens BSI limited to a coronary care unit (CCU). We conducted a retrospective epidemiologic investigation and a case-control study for Pseudomonas fluorescens BSI from April 2011-July 2014. Environmental sample culture was conducted to detect the specific environmental source of transmission. Hospital-wide microbiology data from the term identified 13 case patients with P fluorescens BSI and 32 control patients with BSI due to organisms other than P fluorescens in the CCU. The case-control study revealed that the case group had significantly higher odds of exposure to only cardiac output (CO) measurement with thermodilution method (odds ratio, 22.0; 95% confidence interval, 2.4-202.3). The organism was identified only from an ice bath used for CO measurement. The susceptibility patterns were identical among all strains derived from the cases and the environment. The nosocomial outbreak of P fluorescens BSI in our CCU over 2 years was associated with a contaminated ice bath used for CO measurement within the unit. Detection and elimination of the specific source was essential to stop the outbreak. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  6. Pseudomonas fluorescens SBW25 produces furanomycin, a non-proteinogenic amino acid with selective antimicrobial properties

    Science.gov (United States)

    2013-01-01

    Background Pseudomonas fluorescens SBW25 has been extensively studied because of its plant growth promoting properties and potential as a biocontrol agent. The genome of SBW25 has been sequenced, and among sequenced strains of pseudomonads, SBW25 appears to be most closely related to P. fluorescens WH6. In the authors’ laboratories, WH6 was previously shown to produce and secrete 4-formylaminooxyvinylglycine (FVG), a non-proteinogenic amino acid with selective herbicidal and antimicrobial activity. Although SBW25 does not have the genetic capacity to produce FVG, we were interested in determining whether this pseudomonad might produce some other type of non-proteinogenic amino acid. Results P. fluorescens SBW25 was found to produce and secrete a ninhydrin-reactive compound with selective antimicrobial properties. This compound was purified from SBW25 culture filtrate and identified as the non-proteinogenic amino acid L-furanomycin [2S,2′R,5′S)-2-amino-2-(5′methyl-2′,5′-dihydrofuran-2′-yl)acetic acid]. Conclusions The identification of furanomycin as a secondary metabolite of SBW25 is the first report of the production of furanomycin by a pseudomonad. This compound was known previously only as a natural product produced by a strain of Streptomyces. This report adds furanomycin to the small list of non-proteinogenic amino acids that have been identified as secondary products of pseudomonads. This study also extends the list of bacteria that are inhibited by furanomycin to include several plant pathogenic bacteria. PMID:23688329

  7. Mobile genetic elements in the genome of the beneficial rhizobacterium Pseudomonas fluorescens Pf-5.

    Science.gov (United States)

    Mavrodi, Dmitri V; Loper, Joyce E; Paulsen, Ian T; Thomashow, Linda S

    2009-01-13

    Pseudomonas fluorescens Pf-5 is a plant-associated bacterium that inhabits the rhizosphere of a wide variety of plant species and and produces secondary metabolites suppressive of fungal and oomycete plant pathogens. The Pf-5 genome is rich in features consistent with its commensal lifestyle, and its sequence has revealed attributes associated with the strain's ability to compete and survive in the dynamic and microbiologically complex rhizosphere habitat. In this study, we analyzed mobile genetic elements of the Pf-5 genome in an effort to identify determinants that might contribute to Pf-5's ability to adapt to changing environmental conditions and/or colonize new ecological niches. Sequence analyses revealed that the genome of Pf-5 is devoid of transposons and IS elements and that mobile genetic elements (MGEs) are represented by prophages and genomic islands that collectively span over 260 kb. The prophages include an F-pyocin-like prophage 01, a chimeric prophage 03, a lambdoid prophage 06, and decaying prophages 02, 04 and 05 with reduced size and/or complexity. The genomic islands are represented by a 115-kb integrative conjugative element (ICE) PFGI-1, which shares plasmid replication, recombination, and conjugative transfer genes with those from ICEs found in other Pseudomonas spp., and PFGI-2, which resembles a portion of pathogenicity islands in the genomes of the plant pathogens Pseudomonas syringae and P. viridiflava. Almost all of the MGEs in the Pf-5 genome are associated with phage-like integrase genes and are integrated into tRNA genes. Comparative analyses reveal that MGEs found in Pf-5 are subject to extensive recombination and have evolved in part via exchange of genetic material with other Pseudomonas spp. having commensal or pathogenic relationships with plants and animals. Although prophages and genomic islands from Pf-5 exhibit similarity to MGEs found in other Pseudomonas spp., they also carry a number of putative niche-specific genes that

  8. A modular esterase from Pseudomonas fluorescens subsp. cellulosa contains a non-catalytic cellulose-binding domain.

    OpenAIRE

    Ferreira, L M; Wood, T M; Williamson, G; Faulds, C; Hazlewood, G P; Black, G W; Gilbert, H J

    1993-01-01

    The 5' regions of genes xynB and xynC, coding for a xylanase and arabinofuranosidase respectively, are identical and are reiterated four times within the Pseudomonas fluorescens subsp. cellulosa genome. To isolate further copies of the reiterated xynB/C 5' region, a genomic library of Ps. fluorescens subsp. cellulosa DNA was screened with a probe constructed from the conserved region of xynB. DNA from one phage which hybridized to the probe, but not to sequences upstream or downstream of the ...

  9. Pseudomonas fluorescens

    African Journals Online (AJOL)

    Subhadfip Nandi

    2013-04-10

    Apr 10, 2013 ... Damping off caused by Sclerotium rolfsii on cowpea results in yield losses with serious socio- economic implication. Induction of defense responses by plant growth promoting rhizobacteria (PGPR) is largely associated with the production of defense enzyme phenyl ammonia lyase (PAL) and oxidative.

  10. Effect of a Pseudomonas fluorescens tailocin against phytopathogenic Xanthomonas observed by atomic force microscopy.

    Science.gov (United States)

    Fernandez, Maricruz; Godino, Agustina; Príncipe, Analía; Morales, Gustavo M; Fischer, Sonia

    2017-08-20

    Phage tail-like bacteriocins, called tailocins, represent a class of protein complexes produced by a multitude of bacteria. Pseudomonas fluorescens SF4c, a strain isolated from wheat rhizosphere, produces a bacteriocin similar to phage tail-like pyocins of Pseudomonas aeruginosa. This tailocin has antimicrobial activity against several phytopathogenic strains of the genus Xanthomonas and Pseudomonas. In this work, the effect of the SF4c tailocin on the phytopathogenic strain X. axonopodis pv vesicatoria Xcv Bv5-4a was analyzed through Atomic Force Microscopy (AFM). We demonstrated that tailocins adhere and cause damage to the cell envelope of strain Xcv Bv5-4a. This results in a rapid leakage of intracellular materials, with the subsequent decrease of cell volume. Finally, lysis of sensitive bacteria occurs. This study provides, to our knowledge, the first evidence about the effect of a tailocin analyzed by AFM. Further studies are in progress to evaluate the use of SF4c tailocin in the biocontrol of bacterial spot on tomato. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Evolution of fitness trade-offs in locally adapted populations of Pseudomonas fluorescens

    DEFF Research Database (Denmark)

    Schick, Alana; Bailey, Susan; Kassen, Rees

    2015-01-01

    characterize the genetic causes of trade-offs generating local adaptation in populations of Pseudomonas fluorescens that had previously been evolved for specialization on three different carbon resources. We measured the fitness effects of mutations that arose during selection in that environment...... and in alternative environments to quantify the degree of specialization. We find that all mutations are beneficial in the environment of selection and that those arising later during adaptation are associated with increasingly antagonistic effects in alternative environments compared with those arising earlier......, consistent with a multioptima version of Fisher’s geometric model of adaptation. We also find that fitness of pairs of beneficial mutations are consistently less than additive in selection environments, producing a pattern of diminishing returns, but are more variable in alternative environments, being...

  12. Alginate Biosynthesis Factories in Pseudomonas fluorescens: Localization and Correlation with Alginate Production Level

    Science.gov (United States)

    Maleki, Susan; Almaas, Eivind; Zotchev, Sergey; Valla, Svein

    2015-01-01

    Pseudomonas fluorescens is able to produce the medically and industrially important exopolysaccharide alginate. The proteins involved in alginate biosynthesis and secretion form a multiprotein complex spanning the inner and outer membranes. In the present study, we developed a method by which the porin AlgE was detected by immunogold labeling and transmission electron microscopy. Localization of the AlgE protein was found to depend on the presence of other proteins in the multiprotein complex. No correlation was found between the number of alginate factories and the alginate production level, nor were the numbers of these factories affected in an algC mutant that is unable to produce the precursor needed for alginate biosynthesis. Precursor availability and growth phase thus seem to be the main determinants for the alginate production rate in our strain. Clustering analysis demonstrated that the alginate multiprotein complexes were not distributed randomly over the entire outer cell membrane surface. PMID:26655760

  13. The impact of cellulose nanocrystals on the aggregation and initial adhesion of Pseudomonas fluorescens bacteria.

    Science.gov (United States)

    Sun, Xiaohui; Lu, Qingye; Boluk, Yaman; Liu, Yang

    2014-11-28

    Deposition on silica surfaces of two Pseudomonas fluorescens strains (CHA0 and CHA19-WS) having different extracellular polymeric substance (EPS) producing capacities was studied in the absence and presence of cellulose nanocrystals (CNCs). Batch (batch soaking) and continuous flow (quartz crystal microbalance with dissipation) methods were used to evaluate the impact of CNCs on bacterial initial adhesion. This study demonstrated that bacterial initial adhesion to solid surfaces can be significantly hindered by CNCs using both methods. In the presence of CNCs, it was observed that bacteria with more EPS aggregated more significantly compared to bacteria with less EPS, and that bacterial deposition under this condition decreased to a greater extent. The classic DLVO theory failed to predict bacterial adhesion behavior in this study. A detailed discussion is provided regarding potential antibacterial adhesion mechanisms of CNCs.

  14. Bistability in a Metabolic Network Underpins the De Novo Evolution of Colony Switching in Pseudomonas fluorescens

    DEFF Research Database (Denmark)

    Gallie, Jenna; Libby, Eric; Bertels, Frederic

    2015-01-01

    in central metabolism (carB) generates such a striking phenotype. We show that colony switching is underpinned by ON/OFF expression of capsules consisting of a colanic acid-like polymer. We use molecular genetics, biochemical analyses, and experimental evolution to establish that capsule switching results......Phenotype switching is commonly observed in nature. This prevalence has allowed the elucidation of a number of underlying molecular mechanisms. However, little is known about how phenotypic switches arise and function in their early evolutionary stages. The first opportunity to provide empirical...... insight was delivered by an experiment in which populations of the bacterium Pseudomonas fluorescens SBW25 evolved, de novo, the ability to switch between two colony phenotypes. Here we unravel the molecular mechanism behind colony switching, revealing how a single nucleotide change in a gene enmeshed...

  15. Upon impact: the fate of adhering Pseudomonas fluorescens cells during nanofiltration.

    Science.gov (United States)

    Habimana, Olivier; Semião, Andrea J C; Casey, Eoin

    2014-08-19

    Nanofiltration (NF) is a high-pressure membrane filtration process increasingly applied in drinking water treatment and water reuse processes. NF typically rejects divalent salts, organic matter, and micropollutants. However, the efficiency of NF is adversely affected by membrane biofouling, during which microorganisms adhere to the membrane and proliferate to create a biofilm. Here we show that adhered Pseudomonas fluorescens cells under high permeate flux conditions are met with high fluid shear and convective fluxes at the membrane-liquid interface, resulting in their structural damage and collapse. These results were confirmed by fluorescent staining, flow cytometry, and scanning electron microscopy. This present study offers a "first-glimpse" of cell damage and death during the initial phases of bacterial adhesion to NF membranes and raises a key question about the role of this observed phenomena during early-stage biofilm formation under permeate flux and cross-flow conditions.

  16. Utilization of Pseudomonas fluorescens as Antimicrobial agent on Lipolysis Inhibitition of Rice Bran

    Directory of Open Access Journals (Sweden)

    Titin Widiyastuti

    2002-01-01

    Full Text Available Feedstuff was limited by fat content, certainly, if the material feedstuff was storage on long time periods. Fat was oxidized or hydrolyzed, which was decreased nutritional quality. A Research on Inhibited of  Lypolysis Rice Bran with anti-microbial compound of Pseudomonas fluorescens was conducted during ten month. The research used experiment methods, with Randomized Completely Block Design, storage as block and concentration of anti-mikrobial compound as treatment. Fat and polyunsaturated fatty acids content during storage was observed. Result of experiment showed anti-microbial compound inhibited oxidize and hydrolyze process of fat rice bran during six month storage. (Animal Production 4(2: 89-93 (2002

  17. Semi-scale production of PHAs from waste frying oil by Pseudomonas fluorescens S48

    Science.gov (United States)

    Gamal, Rawia F.; Abdelhady, Hemmat M.; Khodair, Taha A.; El-Tayeb, Tarek S.; Hassan, Enas A.; Aboutaleb, Khadiga A.

    2013-01-01

    The present study aimed at developing a strategy to improve the volumetric production of PHAs by Pseudomonas fluorescens S48 using waste frying oil (WFO) as the sole carbon source. For this purpose, several cultivations were set up to steadily improve nutrients supply to attain high cell density and high biopolymer productivity. The production of PHAs was examined in a 14 L bioreactor as one-stage batch, two-stage batch, and high-cell-density fed-batch cultures. The highest value of polymer content in one-stage bioreactor was obtained after 60 h (33.7%). Whereas, the two-stage batch culture increased the polymer content to 50.1% after 54 h. High-cell-density (0.64 g/L) at continuous feeding rate 0.55 mL/l/h of WFO recorded the highest polymer content after 54 h (55.34%). Semi-scale application (10 L working volume) increased the polymer content in one-stage batch, two-stage batch and high cell density fed-batch cultures by about 12.3%, 5.8% and 11.3%, respectively, as compared with that obtained in 2 L fermentation culture. Six different methods for biopolymer extraction were done to investigate their efficiency for optimum polymer recovery. The maximum efficiency of solvent recovery of PHA was attained by chloroform–hypochlorite dispersion extraction. Gas chromatography (GC) analysis of biopolymer produced by Pseudomonas fluorescens S48 indicated that it solely composed of 3-hydrobutyric acid (98.7%). A bioplastic film was prepared from the obtained PHB. The isolate studied shares the same identical sequence, which is nearly the complete 16S rRNA gene. The identity of this sequence to the closest pseudomonads strains is about 98–99%. It was probably closely related to support another meaningful parsiomony analysis and construction of a phylogenetic tree. The isolate is so close to Egyptian strain named EG 639838. PMID:24294253

  18. BIOCONTROL OF Rhizoctonia solani IN NATIVE POTATO (Solanum phureja PLANTS USING NATIVE Pseudomonas fluorescens

    Directory of Open Access Journals (Sweden)

    GLORIA BAUTISTA

    2007-01-01

    Full Text Available Rhizoctonia solani es un hongo fitopatógeno del suelo, el cual produce una reducción significativa del vigor de las plantas y de la producción de tubérculos en cultivos de papa. Es de gran interés la búsqueda de alternativas de manejo de esta enfermedad, especialmente desde la perspectiva de control biológico ya que los cultivos de papa son los mayores consumidores de plaguicidas de origen químicos en Colombia. Con el objeto de obtener una cepa del grupo de las Pseudomonas fluorescentes con la capa- cidad para reducir los síntomas de la enfermedad producidos por R. solani, se realizó en un estudio previo el aislamiento y caracterización de una colección de aislamientos de Pseudomonas fluorescentes provenientes de diferentes cultivos de la región papera más productiva del país. Seis cepas nativas de P. fluorescens con buena, moderada o ninguna capacidad para inhibir el crecimiento fúngico in vitro fueron seleccionadas. A pesar de las diferencias encontradas en términos de la dinámica y capacidad de colonización, todas las cepas evaluadas indujeron el crecimiento en las plantas de S. phureja y redujeron los síntomas de la enfermedad producidos por R. solani a nivel de invernadero. Nuestros resultados sustentan la conclusión que la asociación de cepas de P. fluorescens con la rizosfera de S. phureja es una alternativa para el manejo de R. solani en papa.

  19. LapD Is a Bis-(3', 5')-Cyclic Dimeric GMP-Binding Protein That Regulates Surface Attachment by Pseudomonas fluorescens Pf0-1

    National Research Council Canada - National Science Library

    Peter D. Newell; Russell D. Monds; George A. O'Toole; Emil C. Gotschlich

    2009-01-01

    .... For Pseudomonas fluorescens Pf0-1, c-di-GMP impacts the secretion and localization of the adhesin LapA, which is absolutely required for stable surface attachment and biofilm formation by this bacterium...

  20. Exposure-related effects of formulated Pseudomonas fluorescens strain CL145A to glochidia from seven unionid mussel species

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Severson, Todd J.; Schreier, Theresa M.; Mayer, Denise A.; Aloisi, Douglas B.; Eckert, Nathan L.

    2015-01-01

    The study was completed to evaluate the exposure-related effects of a biopesticide for dreissenid mussel (Dreissena polymorpha, zebra mussel and Dreissena rostriformis bugensis, quagga mussel) control on glochidia from unionid mussels endemic to the Great Lakes and Upper Mississippi River Basins. The commercially prepared biopesticide was either a spray-dried powder (SDP) or freeze-dried powder (FDP) formulation of Pseudomonas fluorescens, strain CL145A. Glochidia of the unionid mussel species Lampsilis cardium, Lampsilis siliquoidea,Lampsilis higginsii, Ligumia recta, Obovaria olivaria, and Actinonaias ligamentina were exposed to SDP-formulated P. fluorescens andLampsilis cardium and Megalonaias nervosa were exposed to FDP-formulated P. fluorescens.

  1. KAJIAN MEKANISME ANTAGONIS PSEUDOMONAS FLUORESCENS P60 TERHADAP FUSARIUM OXYSPORUM F.SP. LYCOPERSICI PADA TANAMAN TOMAT IN VIVO

    Directory of Open Access Journals (Sweden)

    Loekas Soesanto, Endang Mugiastuti & Ruth Feti Rahayuniati .

    2011-11-01

    Full Text Available Antagonistic mechanisms study of Pseudomonas fluorescens P60 on Fusarium oxysporum f.sp. lycopersici of tomato in vivo.  This research was conducted to evaluate the effect of P. fluorescens P60 in controlling Fusarium wilt on tomato and its inhibition mechanisms. Randomized Block Design was used with four replicates and each consisted of 12 crops. The treatments tested were combination between supernatant or suspension of P. fluorescens P60 and application time, i.e., 5 days before planting, in the same time with planting, and 5 days after planting. Variables observed were phenolic compound (tannin, saponin, and glycoside, disease intensity, infection rate, late pathogen and antagonist population density, crop height, stem diameter, fresh and dry weight of roots, and fresh weight of fruit. The result showed that the application of P. fluorescens P60 either in supernatant or suspension form, could increase phenolic compound in the crop tissue, decrease the Fusarium wilt intensity on tomato as 66.00-77.88%, suppress infection rate as 73.18-79.09%, decrease late F. oxysporum f.sp. lycopersici density as 35.71%, increase the antagonist as 10 fold, increase crop height as 26.50%, improve root dry weight as 55.69%, and increase fruit weight crop-1 as 59.79%. Mechanisms of the antagonist P. fluorescens P60 in order to control the disease in the field were induced resistance, antibiosis, and plant growth promoting rhizobacteria.

  2. Effects of Pseudomonas fluorescens on the Water Parameters of Mycorrhizal and Non-Mycorrhizal Seedlings of Pinus halepensis

    Directory of Open Access Journals (Sweden)

    José A. Saiz de Omeñaca

    2013-08-01

    Full Text Available Inoculation of forest seedlings with mycorrhizal fungi and rhizobacteria can improve the morphological and physiological qualities of plants, especially those used for regeneration of arid areas. In this paper, under standard nursery conditions, Aleppo pine seedlings were inoculated with Pseudomonas fluorescens CECT 5281 rhizobacteria. Some of these seedlings were also inoculated with the ectomycorrhizal fungus Pisolithus tinctorius. Five months after the inoculations, we examined the growth, water parameters (osmotic potential at full turgor [Ψπfull], osmotic potential at zero turgor [Ψπ0], and the tissue modulus of elasticity near full turgor [Emax], mycorrhizal colonisation, and concentration of macronutrients (N, P, K, Ca and Mg in the seedlings. Subsequently, a trial was conducted to assess the root growth potential. P. fluorescens CECT 5281 decreased the cellular osmotic potential of P. halepensis seedlings but increased its elasticity. P. tinctorius + P. fluorescens caused osmotic adjustment at zero turgor and increased tissue elasticity, which improved tolerance to water stress. All inoculations improved the growth and nutrition of the seedlings but caused non-significant effects on root growth potential. The co-inoculation Pisolithus tinctorius + Pseudomonas fluorescens at the nursery may be a suitable technique for producing improved seedling material for restoration purposes.

  3. The nucleotide sequence of a carboxymethylcellulase gene from Pseudomonas fluorescens subsp. cellulosa.

    Science.gov (United States)

    Hall, J; Gilbert, H J

    1988-07-01

    The complete nucleotide sequence of the gene coding for one of the carboxymethylcellulases (CMCase), expressed by Pseudomonas fluorescens subsp. cellulosa, has been determined. The structural gene consists of an open reading frame, commencing with an ATG start codon, of 2886 base pairs followed by a TAA stop codon. The gene was shown to code for a signal peptide which closely resembles the signal peptides of other secreted proteins. Unlike most Pseudomonas genes, the CMCase sequence does not have a high G + C (51%) content and there is no marked preference for codons ending in G or C. Upstream of the structural gene there are no sequences which bear a strong resemblance to consensus Escherichia coli promoters. A sequence is present, however, which exhibits homology to the consensus DNA sequence that binds the catabolic activator protein (CAP). Bal31 deletions of the structural gene revealed the extent by which the gene could be modified and still encode a functional CMCase. Subclones of the cellulase gene have been constructed in pUC18 and pUC19. One of the resultant plasmids, pJHS1 directs a 20-fold increase in CMCase synthesis, when compared to the original construct, pJHH2. Analysis of cells harbouring pJHS1 showed the cellulase polypeptide to have a molecular weight of 106000. This is in close agreement with the predicted size of the enzyme deduced from the nucleotide sequence data.

  4. A phosphate-starvation-inducible outermembrane protein of Pseudomonas fluorescens Ag1 as an immunological phosphate-starvation marker

    DEFF Research Database (Denmark)

    Leopold, Kristine; Jacobsen, Susanne; Nybroe, Ole

    1997-01-01

    A phosphate-starvation-inducible outer-membrane protein of Pseudomonas fluorescens Ag1, expressed at phosphate concentrations below0.08-0.13 mM, was purified and characterized. The purification method involved separation of outer-membrane proteins by SDS-PAGE andextraction of the protein from...... nitrocellulose or PVDF membranes after electrotransfer of proteins to the membranes. The N-terminal amino acidsequence of the purified protein, called Psi1, did not show homology to any known proteins, and in contrast to the phosphate-specific porin OprP ofP. aeruginosa its mobility in SDS-PAGE was not affected...... by solubilization temperature. An antiserum against Psi1 recognized a protein of M,55,000 in four other P. fluorescens strains among 24 tested strains representing Pseudomonas rRNA homology group I, showing antigenicheterogeneity within this group. A method for immunofluorescence microscopy involving cell...

  5. Inhibition of Vibrio anguillarum by Pseudomonas fluorescens AH2, a possible probiotic treatment of fish

    DEFF Research Database (Denmark)

    Gram, Lone; Melchiorsen, Jette; Spanggaard, Bettina

    1999-01-01

    of P.fluorescens AH2 was studied under iron-rich and iron-limited conditions. Sterile-filtered culture supernatants from iron- limited P. fluorescens AH2 inhibited the growth of V. anguillarum, whereas sterile-filtered supernatants from iron- replete cultures of P. fluorescens AH2 did not. P...

  6. Optimization of worm-bed leachate for culturing of tomato (Lycopersicon esculentum Mill) inoculated with Glomus fasciculatum and Pseudomonas fluorescens

    OpenAIRE

    Oliva-Llaven,María Ángela; Rodríguez-Hernández,Ludwi; Mendoza-Nazar,Paula; Ruiz-Sesma, Benigno; Álvarez-Solís,José David; Dendooven, Luc; Federico A. Gutiérrez-Miceli

    2010-01-01

    A response surface technique was used to analyze the effect of Glomus fasciculatum, Pseudomonas fluorescens and worm-bed leachate (WBL) on growth, yield and characteristics of tomato (Lycopersicon esculentum Mill). The treatments combined inoculation with or without P. fluorescensor G. fasciculatum and the application of WBL at 20% (v/v) each day or every three days. Plant height, number of leaves and yield of tomato fruits was not affected by the factors studied. However, plants with foliar ...

  7. Draft genome sequence of the polycyclic aromatic hydrocarbon-degrading, genetically engineered bioluminescent bioreporter Pseudomonas fluorescens HK44.

    Science.gov (United States)

    Chauhan, Archana; Layton, Alice C; Williams, Daniel E; Smartt, Abby E; Ripp, Steven; Karpinets, Tatiana V; Brown, Steven D; Sayler, Gary S

    2011-09-01

    Pseudomonas fluorescens strain HK44 (DSM 6700) is a genetically engineered lux-based bioluminescent bioreporter. Here we report the draft genome sequence of strain HK44. Annotation of ∼6.1 Mb of sequence indicates that 30% of the traits are unique and distributed over five genomic islands, a prophage, and two plasmids. Copyright © 2011, American Society for Microbiology. All Rights Reserved.

  8. Efficacy of Pseudomonas fluorescens (Pf-CL145A) spray dried powder for controlling zebra mussels adhering to test substrates

    Science.gov (United States)

    Luoma, James A.; Severson, Todd J.; Weber, Kerry L.; Mayer, Denise A.

    2015-01-01

    A mobile bioassay trailer was used to assess the efficacy of Pseudomonas fluorescens (Pf-CL145A) spray dried powder (SDP) formulation for controlling zebra mussels (Dreissena polymorpha) from two midwestern lakes: Lake Carlos (Alexandria, Minnesota) and Shawano Lake (Shawano, Wisconsin). The effects of SDP exposure concentration and exposure duration on zebra mussel survival were evaluated along with the evaluation of a benthic injection application technique to reduce the amount of SDP required to induce zebra mortality.

  9. Application of Pseudomonas fluorescens to Blackberry under Field Conditions Improves Fruit Quality by Modifying Flavonoid Metabolism.

    Directory of Open Access Journals (Sweden)

    Daniel Garcia-Seco

    Full Text Available Application of a plant growth promoting rhizobacterium (PGPR, Pseudomonas fluorescens N21.4, to roots of blackberries (Rubus sp. is part of an optimised cultivation practice to improve yields and quality of fruit throughout the year in this important fruit crop. Blackberries are especially rich in flavonoids and therefore offer potential benefits for human health in prevention or amelioration of chronic diseases. However, the phenylpropanoid pathway and its regulation during ripening have not been studied in detail, in this species. PGPR may trigger flavonoid biosynthesis as part of an induced systemic response (ISR given the important role of this pathway in plant defence, to cause increased levels of flavonoids in the fruit. We have identified structural genes encoding enzymes of the phenylpropanoid and flavonoid biosynthetic pathways catalysing the conversion of phenylalanine to the final products including flavonols, anthocyanins and catechins from blackberry, and regulatory genes likely involved in controlling the activity of pathway branches. We have also measured the major flavonols, anthocyanins and catechins at three stages during ripening. Our results demonstrate the coordinated expression of flavonoid biosynthetic genes with the accumulation of anthocyanins, catechins, and flavonols in developing fruits of blackberry. Elicitation of blackberry plants by treatment of roots with P.fluorescens N21.4, caused increased expression of some flavonoid biosynthetic genes and an accompanying increase in the concentration of selected flavonoids in fruits. Our data demonstrate the physiological mechanisms involved in the improvement of fruit quality by PGPR under field conditions, and highlight some of the genetic targets of elicitation by beneficial bacteria.

  10. The cellodextrinase from Pseudomonas fluorescens subsp. cellulosa consists of multiple functional domains.

    Science.gov (United States)

    Ferreira, L M; Hazlewood, G P; Barker, P J; Gilbert, H J

    1991-11-01

    A genomic library of Pseudomonas fluorescens subsp. cellulosa DNA was constructed in pUC18 and Escherichia coli recombinants expressing 4-methylumbelliferyl beta-D-cellobioside-hydrolysing activity (MUCase) were isolated. Enzyme produced by MUCase-positive clones did not hydrolyse either cellobiose or cellotriose but converted cellotetraose into cellobiose and cleaved cellopentaose and cellohexaose, producing a mixture of cellobiose and cellotriose. There was no activity against CM-cellulose, insoluble cellulose or xylan. On this basis, the enzyme is identified as an endo-acting cellodextrinase and is designated cellodextrinase C (CELC). Nucleotide sequencing of the gene (celC) which directs the synthesis of CELC revealed an open reading frame of 2153 bp, encoding a protein of Mr 80,189. The deduced primary sequence of CELC was confirmed by the Mr of purified CELC (77,000) and by the experimentally determined N-terminus of the enzyme which was identical with residues 38-47 of the translated sequence. The N-terminal region of CELC showed strong homology with endoglucanase, xylanases and an arabinofuranosidase of Ps. fluorescens subsp. cellulosa; homologous sequences included highly conserved serine-rich regions. Full-length CELC bound tightly to crystalline cellulose. Truncated forms of celC from which the DNA sequence encoding the conserved domain had been deleted, directed the synthesis of a functional cellodextrinase that did not bind to crystalline cellulose. This is consistent with the N-terminal region of CELC comprising a non-catalytic cellulose-binding domain which is distinct from the catalytic domain. The role of the cellulose-binding region is discussed.

  11. Pseudomonas fluorescens F113 can produce a second flagellar apparatus, which is important for root colonization.

    Directory of Open Access Journals (Sweden)

    Emma Barahona

    2016-09-01

    Full Text Available The genomic sequence of Pseudomonas fluorescens F113 has shown the presence of a 41 kb cluster of genes that encode the production of a second flagellar apparatus. Among 2535 pseudomonads strains with sequenced genomes, these genes are only present in the genomes of F113 and other six strains, all but one belonging to the P. fluorescens cluster of species, in the form of a genetic island. The genes are homologous to the flagellar genes of the soil bacterium Azotobacter vinelandii. Regulation of these genes is mediated by the flhDC master operon, instead of the typical regulation in pseudomonads, which is through fleQ. Under laboratory conditions, F113 does not produce this flagellum and the flhDC operon is not expressed. However, ectopic expression of the flhDC operon is enough for its production, resulting in a hypermotile strain. This flagellum is also produced under laboratory conditions by the kinB and algU mutants. Genetic analysis has shown that kinB strongly represses the expression of the flhDC operon. This operon is activated by the Vfr protein probably in a c-AMP dependent way. The strains producing this second flagellum are all hypermotile and present a tuft of polar flagella instead of the single polar flagellum produced by the wild-type strain. Phenotypic variants isolated from the rhizosphere produce this flagellum and mutation of the genes encoding it, results in a defect in competitive colonization, showing its importance for root colonization.

  12. INFLUÊNCIA DA ATIVIDADE ENZIMÁTICA DE PSEUDOMONAS FLUORESCENS 041 EM LABNEH

    Directory of Open Access Journals (Sweden)

    Andreza Angélica Ferreira

    2012-04-01

    Full Text Available A refrigeração do leite proporciona a seleção de bactérias psicrotróficas deteriorantes produtoras de enzimas termoresistentes que podem comprometer a qualidade do leite e derivados. O objetivo deste trabalho foi avaliar as implicações causadas pela atividade enzimática de Pseudomonas fluorescens 041 na produção de Labneh. O leite pasteurizado foi inoculado intencionalmente com, aproximadamente, 106 UFC.mL-1 de P. fluorescens 041 e Labneh foi produzido imediatamente após inoculação no leite (tempo 0 e após 48, 72 e 96 horas de inoculação e armazenamento a 4 ºC. A qualidade físico-química do leite, do Labneh e do soro resultante da fabricação foi determinada. O rendimento prático, o rendimento técnico ajustado e o aproveitamento final de sólidos no Labneh em relação ao volume de leite (coeficiente GL também foram avaliados. Constatou-se alterações nas características físico-químicas do soro e do Labneh fabricado com leite armazenado a partir de 48 horas. Também, observou-se um aumento significativo em litros de leite destinado à produção de um quilo do produto ao longo do tempo de estocagem do leite inoculado com P. fluorescens 041, sendo os rendimentos prático, técnico ajustado e o coeficiente GL afetados pelo fator tempo. Portanto, a redução do tempo de estocagem do leite sob refrigeração e a prevenção da contaminação da matéria-prima por meio da adoção de boas práticas na cadeia do leite são medidas a serem adotadas para assegurar a qualidade e o rendimento do produto final.

  13. Impact du séchage sur la viabilité de Pseudomonas fluorescens (synthèse bibliographique

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    Mputu Kanyinda, JN.

    2014-01-01

    Full Text Available Impact of drying on Pseudomonas fluorescens viability. A review. Drying Pseudomonas fluorescens makes for more economical storage, transportation and marketing. The aim of the drying process is to stop and to stabilize all biological activity for optimal storage, compatible with the conservation of the maximum desired viability of the microorganisms. However, the viability rate of the bacteria after drying depends on the operating conditions of the drying process. One of the most important criteria to consider during the drying of biologically active products is the quality of the final dried product. Freeze-drying is the drying method most commonly used for Pseudomonas fluorescens. After their production, the bacteria are harvested by centrifugation and are freeze-dried, but the changes in temperature induced by freeze-drying are not without consequence for the cells. The freeze-drying process induces cell damage: peroxidation of fatty acids and proteins and DNA oxidation. However, use of protective compounds during freeze-drying and during storage increases significantly the rate of cell viability.

  14. Semi-scale production of PHAs from waste frying oil by Pseudomonas fluorescens S48

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    Rawia F. Gamal

    2013-01-01

    Full Text Available The present study aimed at developing a strategy to improve the volumetric production of PHAs by Pseudomonas fluorescens S48 using waste frying oil (WFO as the sole carbon source. For this purpose, several cultivations were set up to steadily improve nutrients supply to attain high cell density and high biopolymer productivity. The production of PHAs was examined in a 14 L bioreactor as one-stage batch, two-stage batch, and high-cell-density fed-batch cultures. The highest value of polymer content in one-stage bioreactor was obtained after 60 h (33.7%. Whereas, the two-stage batch culture increased the polymer content to 50.1% after 54 h. High-cell-density (0.64 g/L at continuous feeding rate 0.55 mL/l/h of WFO recorded the highest polymer content after 54 h (55.34%. Semi-scale application (10 L working volume increased the polymer content in one-stage batch, two-stage batch and high cell density fed-batch cultures by about 12.3%, 5.8% and 11.3%, respectively, as compared with that obtained in 2 L fermentation culture. Six different methods for biopolymer extraction were done to investigate their efficiency for optimum polymer recovery. The maximum efficiency of solvent recovery of PHA was attained by chloroform-hypochlorite dispersion extraction. Gas chromatography (GC analysis of biopolymer produced by Pseudomonas fluorescens S48 indicated that it solely composed of 3-hydrobutyric acid (98.7%. A bioplastic film was prepared from the obtained PHB. The isolate studied shares the same identical sequence, which is nearly the complete 16S rRNA gene. The identity of this sequence to the closest pseudomonads strains is about 98-99%. It was probably closely related to support another meaningful parsiomony analysis and construction of a phylogenetic tree. The isolate is so close to Egyptian strain named EG 639838.

  15. Cytokinin production by Pseudomonas fluorescens G20-18 determines biocontrol activity against Pseudomonas syringae in Arabidopsis.

    Science.gov (United States)

    Großkinsky, Dominik K; Tafner, Richard; Moreno, María V; Stenglein, Sebastian A; García de Salamone, Inés E; Nelson, Louise M; Novák, Ondřej; Strnad, Miroslav; van der Graaff, Eric; Roitsch, Thomas

    2016-03-17

    Plant beneficial microbes mediate biocontrol of diseases by interfering with pathogens or via strengthening the host. Although phytohormones, including cytokinins, are known to regulate plant development and physiology as well as plant immunity, their production by microorganisms has not been considered as a biocontrol mechanism. Here we identify the ability of Pseudomonas fluorescens G20-18 to efficiently control P. syringae infection in Arabidopsis, allowing maintenance of tissue integrity and ultimately biomass yield. Microbial cytokinin production was identified as a key determinant for this biocontrol effect on the hemibiotrophic bacterial pathogen. While cytokinin-deficient loss-of-function mutants of G20-18 exhibit impaired biocontrol, functional complementation with cytokinin biosynthetic genes restores cytokinin-mediated biocontrol, which is correlated with differential cytokinin levels in planta. Arabidopsis mutant analyses revealed the necessity of functional plant cytokinin perception and salicylic acid-dependent defence signalling for this biocontrol mechanism. These results demonstrate microbial cytokinin production as a novel microbe-based, hormone-mediated concept of biocontrol. This mechanism provides a basis to potentially develop novel, integrated plant protection strategies combining promotion of growth, a favourable physiological status and activation of fine-tuned direct defence and abiotic stress resilience.

  16. Antimicrobial activity of four essential oils against pigmenting Pseudomonas fluorescens and biofilmproducing Staphylococcus aureus of dairy origin

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    Francesca Pedonese

    2017-12-01

    Full Text Available Essential oils (EOs are mixtures of secondary metabolites of plant origin with many useful properties, among which the antimicrobial activity is also of interest for the food industry. EOs can exert their antimicrobial potential both directly, in food products and active packaging, and indirectly, as sanitizing and anti-biofilm agents of food facility surfaces. Aim of this research was to evaluate the antimicrobial activity of four EOs (bergamot, cinnamon, manuka and thyme against Pseudomonas fluorescens and Staphylococcus aureus isolated from milk and dairy products. The chemical composition of EOs was evaluated by Gas Chromatography-Mass Spectrometry analysis. Minimum Inhibitory Concentration values were determined by a microplate method against 9 Ps. fluorescens from marketed mozzarella with blue discoloration defect, and 3 biofilm-producing S. aureus from milk. Reference ATCC strains were included. Pigment production activity by Ps. fluorescens was assessed both in culture and in cheese. EOs of manuka (leptospermone 23% and thyme (carvacrol 30%, pcymene 20%, thymol 15% showed the highest antimicrobial activity against S. aureus, MIC values were 0.012%-0.024% and 0.024% v/v, respectively; meanwhile EOs from thyme and cinnamon (cinnamaldehyde 55% exhibited the best activity against Ps. fluorescens with MIC values of 0.098%-0.195% and 0.195%-0.391% v/v, respectively. The antimicrobial activity of these EOs is promising and they could be exploited in the dairy production chain.

  17. Understanding the molecular basis of plant growth promotional effect of Pseudomonas fluorescens on rice through protein profiling

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    Thiruvengadam Raguchander

    2009-12-01

    Full Text Available Abstract Background Plant Growth Promoting Rhizobacteria (PGPR, Pseudomonas fluorescens strain KH-1 was found to exhibit plant growth promotional activity in rice under both in-vitro and in-vivo conditions. But the mechanism underlying such promotional activity of P. fluorescens is not yet understood clearly. In this study, efforts were made to elucidate the molecular responses of rice plants to P. fluorescens treatment through protein profiling. Two-dimensional polyacrylamide gel electrophoresis strategy was adopted to identify the PGPR responsive proteins and the differentially expressed proteins were analyzed by mass spectrometry. Results Priming of P. fluorescens, 23 different proteins found to be differentially expressed in rice leaf sheaths and MS analysis revealed the differential expression of some important proteins namely putative p23 co-chaperone, Thioredoxin h- rice, Ribulose-bisphosphate carboxylase large chain precursor, Nucleotide diPhosphate kinase, Proteosome sub unit protein and putative glutathione S-transferase protein. Conclusion Functional analyses of the differential proteins were reported to be directly or indirectly involved in growth promotion in plants. Thus, this study confirms the primary role of PGPR strain KH-1 in rice plant growth promotion.

  18. Metabolic and transcriptomic changes induced in Arabidopsis by the rhizobacterium Pseudomonas fluorescens SS101.

    Science.gov (United States)

    van de Mortel, Judith E; de Vos, Ric C H; Dekkers, Ester; Pineda, Ana; Guillod, Leandre; Bouwmeester, Klaas; van Loon, Joop J A; Dicke, Marcel; Raaijmakers, Jos M

    2012-12-01

    Systemic resistance induced in plants by nonpathogenic rhizobacteria is typically effective against multiple pathogens. Here, we show that root-colonizing Pseudomonas fluorescens strain SS101 (Pf.SS101) enhanced resistance in Arabidopsis (Arabidopsis thaliana) against several bacterial pathogens, including Pseudomonas syringae pv tomato (Pst) and the insect pest Spodoptera exigua. Transcriptomic analysis and bioassays with specific Arabidopsis mutants revealed that, unlike many other rhizobacteria, the Pf.SS101-induced resistance response to Pst is dependent on salicylic acid signaling and not on jasmonic acid and ethylene signaling. Genome-wide transcriptomic and untargeted metabolomic analyses showed that in roots and leaves of Arabidopsis plants treated with Pf.SS101, approximately 1,910 genes and 50 metabolites were differentially regulated relative to untreated plants. Integration of both sets of "omics" data pointed to a prominent role of camalexin and glucosinolates in the Pf.SS101-induced resistance response. Subsequent bioassays with seven Arabidopsis mutants (myb51, cyp79B2cyp79B3, cyp81F2, pen2, cyp71A12, cyp71A13, and myb28myb29) disrupted in the biosynthesis pathways for these plant secondary metabolites showed that camalexin and glucosinolates are indeed required for the induction of Pst resistance by Pf.SS101. Also for the insect S. exigua, the indolic glucosinolates appeared to play a role in the Pf.SS101-induced resistance response. This study provides, to our knowledge for the first time, insight into the substantial biochemical and temporal transcriptional changes in Arabidopsis associated with the salicylic acid-dependent resistance response induced by specific rhizobacteria.

  19. Characterization and expression in Escherichia coli of an endoglucanase gene of Pseudomonas fluorescens subsp. cellulosa.

    Science.gov (United States)

    Lejeune, A; Dartois, V; Colson, C

    1988-07-13

    An endoglucanase gene of Pseudomonas fluorescens subsp. cellulosa present on plasmid pRUCL150 and expressed in Escherichia coli was subcloned in plasmid pBR322. Plasmid pRUCL153 contained the smallest DNA insert (2.9 kb) with endoglucanase activity. The plasmids directed the synthesis of a mostly periplasmic enzyme in E. coli and the level of enzyme activity was comparable in several strains. Analysis by non-denaturing polyacrylamide gel electrophoresis of the endoglucanase produced with various recombinant plasmids showed that it was unique. The endoglucanase gene on plasmid pRUCL153 was localized by physical mapping of independent transposon Tn5 insertions. Hence, its size was estimated to be approx. 1.3 kb. In vivo radioactive labelling of plasmid-encoded proteins using minicells, followed by denaturing polyacrylamide gel electrophoresis, allowed us to determine the size of the endoglucanase: Mr 40,000 for the precursor and Mr 38,000 for the mature enzyme. It was demonstrated that no cellulase operon, but a single gene, was cloned. The direction of transcription of the gene was determined by placing it under the control of the promoter of the lactose operon.

  20. Influence of mineral amendment on disease suppressive activity of Pseudomonas fluorescens to Fusarium wilt of chickpea.

    Science.gov (United States)

    Saikia, Ratul; Varghese, Saju; Singh, Bhim Pratap; Arora, Dilip K

    2009-01-01

    Fusarium wilt caused by Fusarium oxysporum f. sp. ciceri causes considerable yield loss of chickpea. Pseudomonas fluorescens4-92 (Pf4-92) strain can suppress the disease. Amendment of zinc EDTA and copper EDTA could not suppress the disease significantly when used alone; however, they significantly suppressed the disease in presence of Pf4-92. In vitro observation showed that at 40, 30 and 20microgml(-1) concentrations of these minerals, i.e. Zn, Cu and Zn plus Cu, respectively, completely repressed the production of the phytotoxin, fusaric acid (FA). FA concentration (0.5microgml(-1)) has been shown to suppress the production of 2,4-diacetylphloroglucinol (DAPG) by Pf4-92, and DAPG, salicylic acid, pyochelin and pyoluteorin production was enhanced by these mineral amendments. In rockwool bioassays, Zn, Cu and Zn plus Cu amendments reduced FA production and enhanced DAPG production. This study demonstrates that Zn and Cu enhance biocontrol activity by reducing FA produced by the pathogen, F. oxysporum f. sp. ciceri.

  1. Colonisation of Pinus halepensis roots by Pseudomonas fluorescens and interaction with the ectomycorrhizal fungus Suillus granulatus.

    Science.gov (United States)

    Rincón, Ana; Ruiz-Díez, Beatriz; García-Fraile, Sonia; García, José Antonio Lucas; Fernández-Pascual, Mercedes; Pueyo, José J; de Felipe, María R

    2005-02-01

    Colonisation of Pinus halepensis roots by GFP-tagged Pseudomonas fluorescens Aur6 was monitored by epifluorescence microscopy and dilution plating. Aur6-GFP was able to colonise and proliferate on P. halepensis roots. Co-inoculation with the ectomycorrhizal fungus Suillus granulatus did not affect the bacterial colonisation pattern whereas it had an effect on bacterial density. Bacterial counts increased during the first 20 days of seedling growth, irrespective of seedlings being mycorrhizal or not. After 40 days, bacterial density significantly decreased and bacteria concentrated on the upper two-thirds of the pine root. The presence of S. granulatus significantly stimulated survival of bacteria in the root elongation zone where fungal colonisation was higher. The number of mycorrhizas formed by S. granulatus was not affected by co-inoculation with Aur6-GFP. Neither Aur6-GFP nor S. granulatus stimulated P. halepensis development when inoculated alone, but a synergistic effect was observed on seedling growth when bacteria and fungus were co-inoculated.

  2. Extracellular enzyme production and cheating in Pseudomonas fluorescens depend on diffusion rates.

    Science.gov (United States)

    Allison, Steven D; Lu, Lucy; Kent, Alyssa G; Martiny, Adam C

    2014-01-01

    Bacteria produce extracellular enzymes to obtain resources from complex chemical substrates, but this strategy is vulnerable to cheating by cells that take up reaction products without paying the cost of enzyme production. We hypothesized that cheating would suppress enzyme production in co-cultures of cheater and producer bacteria, particularly under well-mixed conditions. To test this hypothesis, we monitored protease expression and frequencies of Pseudomonas fluorescens producer and cheater genotypes over time in mixed liquid cultures and on agar plates. In mixed culture inoculated with equal frequencies of cheaters and producers, enzyme concentration declined to zero after 20 days, consistent with our hypothesis. We observed a similar decline in cultures inoculated with producers only, suggesting that cheater mutants arose de novo and swept the population. DNA sequencing showed that genetic changes most likely occurred outside the protease operon. In one experimental replicate, the population regained the ability to produce protease, likely due to further genetic changes or population dynamics. Under spatially structured conditions on agar plates, cheaters did not sweep the population. Instead, we observed a significant increase in the variation of enzyme activity levels expressed by clones isolated from the population. Together these results suggest that restricted diffusion favors a diversity of enzyme production strategies. In contrast, well-mixed conditions favor population sweeps by cheater strains, consistent with theoretical predictions. Cheater and producer strategies likely coexist in natural environments with the frequency of cheating increasing with diffusion rate.

  3. Cheating and resistance to cheating in natural populations of the bacterium Pseudomonas fluorescens.

    Science.gov (United States)

    Bruce, John B; Cooper, Guy A; Chabas, Hélène; West, Stuart A; Griffin, Ashleigh S

    2017-10-01

    Bacteria perform cooperative behaviors that are exploitable by noncooperative cheats, and cheats frequently arise and coexist with cooperators in laboratory microcosms. However, evidence of competitive dynamics between cooperators and cheats in nature remains limited. Using the production of pyoverdine, an iron-scavenging molecule, and natural soil populations of Pseudomonas fluorescens, we found that (1) nonproducers are present in the population; (2) they co-occur (cheats in soil: utilizing the pyoverdine of others while producing little or none themselves. However, we found considerable variation in the extent to which nonproducers can exploit producers, as some isolates appear to produce exclusive forms of pyoverdine or kill nonproducers with toxins. We examined the consequences of this variation using theoretical modeling. We found variance in exploitability leads to some cheats gaining increased fitness benefits and others decreased benefits. However, the absolute gain in fitness from high exploitation is lower than the drop in fitness from low exploitation, decreasing the mean fitness of cheats and subsequently lowering the proportion of cheats maintained in the population. Our results suggest that although cooperator-cheat dynamics can occur in soil, a range of mechanisms can prevent nonproducers from exploiting producers. © 2017 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

  4. Pseudomonas fluorescens R68 assisted enhancement in growth and fertilizer utilization of Amaranthus tricolor (L.).

    Science.gov (United States)

    Jimtha John, C; Jishma, P; Karthika, N R; Nidheesh, K S; Ray, J G; Mathew, Jyothis; Radhakrishnan, E K

    2017-08-01

    Plant probiotic potential of rhizosphere microbiome and its role in phytofertilizer mobilization are largely unexplored. In the current study, the rhizobacterium Pseudomonas fluorescens R68 (PFR68) isolated from Western Ghat was analyzed for its growth enhancement effect on the leafy vegetable Amaranthus tricolor (L.). One month of field growth of PFR68 inoculated A. tricolor has found to have enhanced growth parameters such as leaf number (1.57 fold), root number (1.76 fold), shoot length (1.28 fold) and fresh weight (2.31 fold). The treatment also improved soil fertility in terms of Nitrogen, Phosphorus and Potassium content. Most remarkably, application of PFR68 alone and 50% of recommended NPK dose along with PFR68 has resulted in enhanced growth of A. tricolor comparable to plants treated with full dose of NPK. In addition to this, application of PFR68 along with 50% NPK augmented the available Nitrogen and Phosphorus content in soil. This indicates the potential of selected organism in enrichment of soil health and enhancement of crop productivity. In conclusion, field performance of PFR68 on growth of A. tricolor confirms its promises to develop into plant probiotic formulation.

  5. Milk-deteriorating exoenzymes from Pseudomonas fluorescens 041 isolated from refrigerated raw milk

    Science.gov (United States)

    Martins, Maurilio L.; Pinto, Uelinton M.; Riedel, Katharina; Vanetti, Maria C.D.

    2015-01-01

    The practice of refrigerating raw milk at the farm has provided a selective advantage for psychrotrophic bacteria that produce heat-stable proteases and lipases causing severe quality problems to the dairy industry. In this work, a protease (AprX) and a lipase (LipM) produced by Pseudomonas fluorescens 041, a highly proteolytic and lipolytic strain isolated from raw milk obtained from a Brazilian farm, have been purified and characterized. Both enzymes were purified as recombinant proteins from Escherichia coli . The AprX metalloprotease exhibited activity in a broad temperature range, including refrigeration, with a maximum activity at 37 °C. It was active in a pH range of 4.0 to 9.0. This protease had maximum activity with the substrates casein and gelatin in the presence of Ca +2 . The LipM lipase had a maximum activity at 25 °C and a broad pH optimum ranging from 7.0 to 10. It exhibited the highest activity, in the presence of Ca +2 , on substrates with long-chain fatty acid residues. These results confirm the spoilage potential of strain 041 in milk due to, at least in part, these two enzymes. The work highlights the importance of studies of this kind with strains isolated in Brazil, which has a recent history on the implementation of the cold chain at the dairy farm. PMID:26221110

  6. Pit formation on stainless steel surfaces pre-treated with biosurfactants produced by Pseudomonas fluorescens

    Energy Technology Data Exchange (ETDEWEB)

    Dagbert, Catherine [ECP-LGPM, Grande Voie des Vignes, 92295 Chatenay-Malabry (France)], E-mail: catherine.dagbert@ecp.fr; Meylheuc, Thierry; Bellon-Fontaine, Marie-Noelle [INRA, UMR 763 Bioadhesion et Hygiene des Materiaux, F-91300 Massy (France); AGROPARISTECH, UMR 763 Bioadhesion et Hygiene des Materiaux, F-91300 Massy (France)

    2008-12-01

    Today, it is widely established that the surface tension of water can be reduced by some microorganisms capable of synthesizing surface-active compounds called biosurfactants (BS). BS characteristics depend on the microorganism that produces them and therefore, on the microorganism culture conditions. Some studies on chemical surfactants have shown that the adsorption of surface-active compounds plays a major role in corrosion; indeed they are used as a good corrosion inhibition tool. The purpose of this study was first, to estimate the importance and behavior of the stainless steels passive film on the adsorption of BS, produced by the Gram negative bacteria Pseudomonas fluorescens, and secondly, to study the impact of these treatments on the pitting corrosion. In this paper, the galvanostatic polarization technique, used as accelerated method for determining the characteristic pit potentials on stainless steels, is examined. Pit growth, shape and cover formation were also observed. The surface topography of the corroded specimens was investigated using field emission scanning electron microscopy (FESEM)

  7. Correlation of Carbohydrate Catabolism and Synthesis of Macromolecules During Enzyme Synthesis in Pseudomonas fluorescens.

    Science.gov (United States)

    Kirkland, J J; Durham, N N

    1965-07-01

    Kirkland, Jerry J. (Oklahoma State University, Stillwater), and Norman N. Durham. Correlation of carbohydrate catabolism and synthesis of macromolecules during enzyme synthesis in Pseudomonas fluorescens. J. Bacteriol. 90: 23-28. 1965.-Glucose, ribose, and fructose shorten the lag period required for synthesis of protocatechuate oxygenase. Radioactivity from uracil-2-C(14) is incorporated into the hot trichloroacetic acid-soluble fraction after a lag period of approximately 20 min after addition of protocatechuic acid. Addition of glucose or ribose simultaneously with the inducer shortens the lag period to approximately 5 min and increases the rate of uracil incorporation. The inducer must be present to initiate incorporation of radioactivity, and the exogenous carbon source accelerates incorporation but is not sufficient to initiate synthesis by itself. The addition of protocatechuic acid increases the rate and total incorporation of radioactivity from uniformly labeled glucose or ribose-1-C(14) into the hot trichloroacetic acid-soluble fraction. Ribose decreases the incorporation of radioactivity from uniformly labeled glucose into the hot trichloroacetic acid-soluble fraction, and glucose shows a similar effect on incorporation of radioactivity from ribose-1-C(14), indicating the two sugars are serving in the same capacity to enhance enzyme synthesis. Radioactivity from glucose-1-C(14) is not incorporated into the hot trichloroacetic acid-soluble fraction. The results suggest that glucose and ribose shorten the lag period for inducible enzyme formation by serving as a "specific" carbon source for synthesis of macromolecules such as ribonucleic acid.

  8. Adhesion of Pseudomonas fluorescens biofilms to glass, stainless steel and cellulose.

    Science.gov (United States)

    Wan Dagang, W R Z; Bowen, J; O'Keeffe, J; Robbins, P T; Zhang, Z

    2016-05-01

    The adhesion of colloidal probes of stainless steel, glass and cellulose to Pseudomonas fluorescens biofilms was examined using atomic force microscopy (AFM) to allow comparisons between surfaces to which biofilms might adhere. Biofilm was grown on a stainless steel substrate and covered most of the surface after 96 h. AFM approach and retraction curves were obtained when the biofilm was immersed in a tryptone/soy medium. On approach, all the colloidal probes experienced a long non-contact phase more than 100 nm in length, possibly due to the steric repulsion by extracellular polymers from the biofilm and hydrophobic effects. Retraction data showed that the adhesion varied from position to position on the biofilm. The mean value of adhesion of glass to the biofilm (48 ± 7 nN) was the greatest, followed by stainless steel (30 ± 7 nN) and cellulose (7.8 ± 0.4 nN). The method allows understanding of adhesion between the three materials and biofilm, and development of a better strategy to remove the biofilm from these surfaces relevant to different industrial applications.

  9. Promotion of plant growth by Pseudomonas fluorescens strain SS101 via novel volatile organic compounds.

    Science.gov (United States)

    Park, Yong-Soon; Dutta, Swarnalee; Ann, Mina; Raaijmakers, Jos M; Park, Kyungseok

    2015-05-29

    Volatile organic compounds (VOCs) from plant growth-promoting rhizobacteria (PGPR) play key roles in modulating plant growth and induced systemic resistance (ISR) to pathogens. Despite their significance, the physiological functions of the specific VOCs produced by Pseudomonas fluorescens SS101 (Pf.SS101) have not been precisely elucidated. The effects of Pf.SS101 and its VOCs on augmentation of plant growth promotion were investigated in vitro and in planta. A significant growth promotion was observed in plants exposed Pf.SS101 under both conditions, suggesting that its VOCs play a key role in promoting plant growth. Solid-phase micro-extraction (SPME) and a gas chromatography-mass spectrophotometer (GC-MS) system were used to characterize the VOCs emitted by Pf.SS101 and 11 different compounds were detected in samples inoculated this bacterium, including 13-Tetradecadien-1-ol, 2-butanone and 2-Methyl-n-1-tridecene. Application of these compounds resulted in enhanced plant growth. This study suggests that Pf.SS101 promotes the growth of plants via the release of VOCs including 13-Tetradecadien-1-ol, 2-butanone and 2-Methyl-n-1-tridecene, thus increasing understanding of the role of VOCs in plant-bacterial inter-communication. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Small RNA-dependent expression of secondary metabolism is controlled by Krebs cycle function in Pseudomonas fluorescens.

    Science.gov (United States)

    Takeuchi, Kasumi; Kiefer, Patrick; Reimmann, Cornelia; Keel, Christoph; Dubuis, Christophe; Rolli, Joëlle; Vorholt, Julia A; Haas, Dieter

    2009-12-11

    Pseudomonas fluorescens CHA0, an antagonist of phytopathogenic fungi in the rhizosphere of crop plants, elaborates and excretes several secondary metabolites with antibiotic properties. Their synthesis depends on three small RNAs (RsmX, RsmY, and RsmZ), whose expression is positively controlled by the GacS-GacA two-component system at high cell population densities. To find regulatory links between primary and secondary metabolism in P. fluorescens and in the related species Pseudomonas aeruginosa, we searched for null mutations that affected central carbon metabolism as well as the expression of rsmY-gfp and rsmZ-gfp reporter constructs but without slowing down the growth rate in rich media. Mutation in the pycAB genes (for pyruvate carboxylase) led to down-regulation of rsmXYZ and secondary metabolism, whereas mutation in fumA (for a fumarase isoenzyme) resulted in up-regulation of the three small RNAs and secondary metabolism in the absence of detectable nutrient limitation. These effects required the GacS sensor kinase but not the accessory sensors RetS and LadS. An analysis of intracellular metabolites in P. fluorescens revealed a strong positive correlation between small RNA expression and the pools of 2-oxoglutarate, succinate, and fumarate. We conclude that Krebs cycle intermediates (already known to control GacA-dependent virulence factors in P. aeruginosa) exert a critical trigger function in secondary metabolism via the expression of GacA-dependent small RNAs.

  11. Characterization of a Pseudomonas fluorescens strain from tomato rhizosphere and its use for integrated management of tomato damping-off

    Energy Technology Data Exchange (ETDEWEB)

    Jayaraj, J; Parthasarathi, T.; Radhakrishnan, N.V. [Annamalai University, Annamalainagar (India). Faculty of Agriculture

    2007-10-15

    A highly antagonistic Pseudomonas fluorescens strain was isolated from tomato rhizosphere and characterized for its in vitro and in vivo biocontrol potential against Pythium aphanidermatum. The identified Pseudomonas fluorescens strain (PfT-8) was capable of producing high levels of chitinase, beta-1,3-glucanase, cellulase, fungitoxic metabolites and siderophores. Seven different carrier formulations including a talc-based powder, lignite-based powder, peat-based powder, lignite + fly ash-based powder, wettable powder, bentonite-paste and polyethylene glycol (PEG) paste were prepared utilizing PfT-8. Shelf life was evaluated for up to 6 months of storage at ambient room temperature (28{sup o}C). Biocontrol efficacy of formulations was studied under greenhouse and field conditions. Among the formulations, peat, lignite, lignite+fly-ash and bentonite paste based formulations maintained higher propagule number than others and also showed greater biocontrol potential. However, propagule number gradually decreased with time. Soil incorporation of organic amendments and specifically poultry manure and FYM, significantly reduced damping-off incidence and also augmented the rhizosphere population of the marked P. fluorescens strain that was resistant to streptomycin and rifampicin.

  12. Combinatorial efficacy of Trichoderma spp. and Pseudomonas fluorescens to enhance suppression of cell wall degrading enzymes produced by Fusarium wilt of Arachis hypogaea.L

    Directory of Open Access Journals (Sweden)

    P Rajeswari

    2017-12-01

    Full Text Available Fusarium oxysporum, the soil borne pathogen causes vascular wilt, on majority of crop plants. It has been demonstrated that two different species of Trichoderma and Pseudomonas fluorescens suppress disease by different mechanisms. Therefore, application of a mixture of these biocontrol agents, and thus of several suppressive mechanisms, may represent a viable control strategy. A necessity for biocontrol by combinations of biocontrol agents can be the compatibility of the co-inoculated micro-organisms. Hence, compatibility between Trichoderma spp. and Pseudomonas fluorescens that have the ability to suppress Fusarium oxysporum in vitro on the activity of pectinolytic enzymes of Fusarium oxysporum. The activity of pectinolytic enzymes, i.e. pectin methyl esterase, endo and exo polymethylgalacturonases and exo and endo pectin trans eliminases produced by Fusarium oxysporum (Control was higher. Maximum inhibition of pectin methylesterase, exo and endo polymethylgalacturonase and exo and endopectin trans eliminase was shown by culture filtrate of Trichoderma viride + Pseudomonas fluorescens (Tv+Pf (1+2%, followed by Trichoderma harzianum + Pseudomonas fluorescens, (Th +Pf (1.5+2% and Trichoderma viride + Trichoderma harzianum (Tv+Th (1+1.5%. However, pathogenecity suppression of Fusarium oxysporum, a causative of Arachis hypogaea. L by the compatible combination of Trichodema viride + Pseudomonas fluorescens (1+2% was significantly better as compared to the single bio-agent. This indicates that specific interactions between biocontrol agents influence suppression of pathogenicity factors directly by combinations of these compatible bio-agents.

  13. Pseudomonas fluorescens HK44: lessons learned from a model whole-cell bioreporter with a broad application history.

    Science.gov (United States)

    Trögl, Josef; Chauhan, Archana; Ripp, Steven; Layton, Alice C; Kuncová, Gabriela; Sayler, Gary S

    2012-01-01

    Initially described in 1990, Pseudomonas fluorescens HK44 served as the first whole-cell bioreporter genetically endowed with a bioluminescent (luxCDABE) phenotype directly linked to a catabolic (naphthalene degradative) pathway. HK44 was the first genetically engineered microorganism to be released in the field to monitor bioremediation potential. Subsequent to that release, strain HK44 had been introduced into other solids (soils, sands), liquid (water, wastewater), and volatile environments. In these matrices, it has functioned as one of the best characterized chemically-responsive environmental bioreporters and as a model organism for understanding bacterial colonization and transport, cell immobilization strategies, and the kinetics of cellular bioluminescent emission. This review summarizes the characteristics of P. fluorescens HK44 and the extensive range of its applications with special focus on the monitoring of bioremediation processes and biosensing of environmental pollution.

  14. Pseudomonas fluorescens HK44: Lessons Learned from a Model Whole-Cell Bioreporter with a Broad Application History

    Directory of Open Access Journals (Sweden)

    Gary S. Sayler

    2012-02-01

    Full Text Available Initially described in 1990, Pseudomonas fluorescens HK44 served as the first whole-cell bioreporter genetically endowed with a bioluminescent (luxCDABE phenotype directly linked to a catabolic (naphthalene degradative pathway. HK44 was the first genetically engineered microorganism to be released in the field to monitor bioremediation potential. Subsequent to that release, strain HK44 had been introduced into other solids (soils, sands, liquid (water, wastewater, and volatile environments. In these matrices, it has functioned as one of the best characterized chemically-responsive environmental bioreporters and as a model organism for understanding bacterial colonization and transport, cell immobilization strategies, and the kinetics of cellular bioluminescent emission. This review summarizes the characteristics of P. fluorescens HK44 and the extensive range of its applications with special focus on the monitoring of bioremediation processes and biosensing of environmental pollution.

  15. Control biológico de Rhizoctonia solani en plantas de papa criollaSolanum phureja usando cepas nativas de Pseudomonas fluorescens BIOCONTROL OF Rhizoctonia solani IN NATIVE POTATO (Solanum phureja PLANTS USING NATIVE Pseudomonas fluorescens

    Directory of Open Access Journals (Sweden)

    GLORIA BAUTISTA

    2007-06-01

    Full Text Available Rhizoctonia solani es un hongo fitopatógeno del suelo, el cual produce una reducción significativa del vigor de las plantas y de la producción de tubérculos en cultivos de papa. Es de gran interés la búsqueda de alternativas de manejo de esta enfermedad, especialmente desde la perspectiva de control biológico ya que los cultivos de papa son los mayores consumidores de plaguicidas de origen químicos en Colombia. Con el objeto de obtener una cepa del grupo de las Pseudomonas fluorescentes con la capacidad para reducir los síntomas de la enfermedad producidos por R. solani, se realizó en un estudio previo el aislamiento y caracterización de una colección de aislamientos de Pseudomonas fluorescentes provenientes de diferentes cultivos de la región papera más productiva del país. Seis cepas nativas de P. fluorescens con buena, moderada o ninguna capacidad para inhibir el crecimiento fúngico in vitro fueron seleccionadas. A pesar de las diferencias encontradas en términos de la dinámica y capacidad de colonización, todas las cepas evaluadas indujeron el crecimiento en las plantas de S. phureja y redujeron los síntomas de la enfermedad producidos por R. solani a nivel de invernadero. Nuestros resultados sustentan la conclusión que la asociación de cepas de P. fluorescens con la rizosfera de S. phureja es una alternativa para el manejo de R. solani en papa.Rhizoctonia solani is a soil borne phytopathogen associated with reduced plant vigor and tuber production in potato crops. There is a huge interest to search alternatives of biological control management of this disease, because the potato crops in Colombia are the highest consumers of chemical pesticides in Colombia. In order to obtain a fluorescent Pseudomonas strain with the capacity to reduce the disease symptoms produced by R. solani, determination and isolation of the predominant fluorescent Pseudomonas in several potato crops of the main Colombian producing region was done

  16. Pemanfaatan Beberapa Kaldu Hewan sebagai Bahan Formula Cair Pseudomonas fluorescens P60 untuk Mengendalikan Sclerotium rolfsii pada Tanaman Mentimun

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    Endang Mugiastuti

    2011-07-01

    Full Text Available A research aiming at knowing the potency of several animal broths as organic liquid formula of Pseudomonas fluorescens P60, soaking period of Sclerotium rolfsii sclerotia, and its application method on cucumber stem-end rot was done. Completely randomized design and randomized block design both arranged by factorial were used for in vitro and in planta tests, respectively. The first factor was six kinds of animal broth, i.e., golden snail, local chicken,broiler chicken, catfish, cow bone, and rat. The second one for in vitro test was the soaking period in the Pseudomonas fluorescens P60 formula, i.e., 0, 1, 10, and 100 hours and for in planta one was application methods, i.e., seed soaking or crop spraying. Result of the research showed that the best animal broth as liquid formula for Pseudomonas fluorescens P60 was golden snail broth indicated by suppression of sclerotial germination up to 97.4% after soaking for 100 hours. The best application method to suppress the disease was spraying method showed by suppressed of sclerotial germination, longer incubation period, and suppressed disease incidence and sclerotial late population of 55.79, 147.35, 66.67, and 59.68%, repectively. Spraying the formula could also increase crop height difference, fresh and dry weight of crop, fresh and dry weight of root, and root length to 146.83, 86.62, 112.5, 87.88, 140, and 159.68%, respectively. Penelitian dengan tujuan untuk mengetahui potensi beberapa kaldu hewan sebagai formula cair organik Pseudomonas fluorescens P60, lama perendaman sklerotium Sclerotium rolfsii, dan cara aplikasinya terhadap penyakit busuk pangkal batang mentimun dilakukan. Rancangan acak lengkap faktorial dan rancangan acak kelompok faktorial digunakan dalam penelitian in vitro dan in planta. Faktor pertama yang diuji adalah enam jenis kaldu yang terdiri atas kaldu keong mas, ayam kampung, ayam potong, ikan lele, tulang sapi, dan tikus. Faktor kedua pada penelitian in vitro adalah lama

  17. Biocontrol of collar rot disease of betelvine (Piper betle L.) caused by Sclerotium rolfsii by using rhizosphere-competent Pseudomonas fluorescens NBRI-N6 and P. fluorescens NBRI-N.

    Science.gov (United States)

    Singh, Anand; Mehta, Sangeeta; Singh, Harikesh Bahadur; Nautiyal, Chandra Shekhar

    2003-08-01

    Collar rot disease of betelvine (Piper betle L.) caused by Sclerotium rolfsii is difficult to control by conventional means by use of chemicals; therefore, use of biocontrol agents is desirable. In the present study, 186 bacterial strains of different morphological types were screened for their biocontrol activity against S. rolfsii under in vitro conditions. Two strains, Pseudomonas fluorescens NBRI-N6 and P. fluorescens NBRI-N, were selected for further studies because of their ability to inhibit the mycelial growth of the pathogen significantly. Spontaneous rifampicin-resistant (Rif) derivatives of P. fluorescens NBRI-N6 and P. fluorescens NBRI-N showing growth rate and membrane protein composition comparable to the wild type were selected to facilitate their monitoring in the rhizosphere. Field trials demonstrated that strain P. fluorescens NBRI-N6 was better than P. fluorescens NBRI-N in increasing the yield of betelvine significantly, whereas a consortium of the two strains controlled the disease more than either of the strains. The screening method should prove useful in identifying rhizosphere bacteria with the greatest potential for controlling diseases caused by phytopathogenic fungi.

  18. Pyrroloquinoline Quinone Is a Plant Growth Promotion Factor Produced by Pseudomonas fluorescens B161

    Science.gov (United States)

    Choi, Okhee; Kim, Jinwoo; Kim, Jung-Gun; Jeong, Yeonhwa; Moon, Jae Sun; Park, Chang Seuk; Hwang, Ingyu

    2008-01-01

    Pseudomonas fluorescens B16 is a plant growth-promoting rhizobacterium. To determine the factors involved in plant growth promotion by this organism, we mutagenized wild-type strain B16 using ΩKm elements and isolated one mutant, K818, which is defective in plant growth promotion, in a rockwool culture system. A cosmid clone, pOK40, which complements the mutant K818, was isolated from a genomic library of the parent strain. Tn3-gusA mutagenesis of pOK40 revealed that the genes responsible for plant growth promotion reside in a 13.3-kb BamHI fragment. Analysis of the DNA sequence of the fragment identified 11 putative open reading frames, consisting of seven known and four previously unidentified pyrroloquinoline quinone (PQQ) biosynthetic genes. All of the pqq genes showed expression only in nutrient-limiting conditions in a PqqH-dependent manner. Electrospray ionization-mass spectrometry analysis of culture filtrates confirmed that wild-type B16 produces PQQ, whereas mutants defective in plant growth promotion do not. Application of wild-type B16 on tomato (Solanum lycopersicum) plants cultivated in a hydroponic culture system significantly increased the height, flower number, fruit number, and total fruit weight, whereas none of the strains that did not produce PQQ promoted tomato growth. Furthermore, 5 to 1,000 nm of synthetic PQQ conferred a significant increase in the fresh weight of cucumber (Cucumis sativus) seedlings, confirming that PQQ is a plant growth promotion factor. Treatment of cucumber leaf discs with PQQ and wild-type B16 resulted in the scavenging of reactive oxygen species and hydrogen peroxide, suggesting that PQQ acts as an antioxidant in plants. PMID:18055583

  19. Pyrroloquinoline quinone is a plant growth promotion factor produced by Pseudomonas fluorescens B16.

    Science.gov (United States)

    Choi, Okhee; Kim, Jinwoo; Kim, Jung-Gun; Jeong, Yeonhwa; Moon, Jae Sun; Park, Chang Seuk; Hwang, Ingyu

    2008-02-01

    Pseudomonas fluorescens B16 is a plant growth-promoting rhizobacterium. To determine the factors involved in plant growth promotion by this organism, we mutagenized wild-type strain B16 using OmegaKm elements and isolated one mutant, K818, which is defective in plant growth promotion, in a rockwool culture system. A cosmid clone, pOK40, which complements the mutant K818, was isolated from a genomic library of the parent strain. Tn3-gusA mutagenesis of pOK40 revealed that the genes responsible for plant growth promotion reside in a 13.3-kb BamHI fragment. Analysis of the DNA sequence of the fragment identified 11 putative open reading frames, consisting of seven known and four previously unidentified pyrroloquinoline quinone (PQQ) biosynthetic genes. All of the pqq genes showed expression only in nutrient-limiting conditions in a PqqH-dependent manner. Electrospray ionization-mass spectrometry analysis of culture filtrates confirmed that wild-type B16 produces PQQ, whereas mutants defective in plant growth promotion do not. Application of wild-type B16 on tomato (Solanum lycopersicum) plants cultivated in a hydroponic culture system significantly increased the height, flower number, fruit number, and total fruit weight, whereas none of the strains that did not produce PQQ promoted tomato growth. Furthermore, 5 to 1,000 nm of synthetic PQQ conferred a significant increase in the fresh weight of cucumber (Cucumis sativus) seedlings, confirming that PQQ is a plant growth promotion factor. Treatment of cucumber leaf discs with PQQ and wild-type B16 resulted in the scavenging of reactive oxygen species and hydrogen peroxide, suggesting that PQQ acts as an antioxidant in plants.

  20. Effect of exogenous ectoines on some antifungal activity of Pseudomonas fluorescens UTPF5 under salt conditions

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    Arghavan Kamaly

    2016-06-01

    Full Text Available Introduction: Plant probiotic bacteria like fluorescent pseudomonads are worldly used against soil-borne pathogens through mechanisms such as production of bacterial metabolites and enzymes. These bacteria can also help plants to tolerate environmental stresses. Ectoine is a compatible solution which plays an important role in environmental osmotic stresses. Materials and methods: Tolerance of 24 bacterial strains to salt and heat was tested and 6 tolerant strains were chosen. Then dual culture of Fusarium solani and bacteria grown in presence of ectoine and hydroxy ectoine with 3 NaCl concentrations (0, 150 and 300 mM was done and Pseudomonas fluorescens UTPF5 was selected. Finally the effect of ectoine, hydroxyectoine and NaCl on bacterial population, lipase, protease, siderophore and hydrogen-cyanide production and biofilm formation was investigated. Results: In 300 mM NaCl, the bacterium grown in presence of ectoines, increased the inhibition percentage 5- times more than control. NaCl had a positive effect on bacterial population in water and ectoine, hydrogen-cyanide production in all treatment and biofilm formation in ectoine and hydroxyectoine and negative effect on bacterial population in hydroxyectoine, protease and siderophore production in all treatments and biofilm formation in water. On the other hand, ectoine increased lipase and hydrogen-cyanide production and biofilm formation in 300 mM NaCl and siderophore production in 150 mM. Hydroxyectoine had similar effects with little differences. Discussion and conclusion: Ectoine and hydroxyectoine moderate the biocontrol reduction in presence of NaCl through positive effect on lipase and hydrogen-cyanide production and biofilm formation.

  1. Cost of Adaptation and Fitness Effects of Beneficial Mutations in Pseudomonas fluorescens

    Science.gov (United States)

    Bataillon, Thomas; Zhang, Tianyi; Kassen, Rees

    2011-01-01

    Adaptations are constructed through the sequential substitution of beneficial mutations by natural selection. However, the rarity of beneficial mutations has precluded efforts to describe even their most basic properties. Do beneficial mutations typically confer small or large fitness gains? Are their fitness effects environment specific, or are they broadly beneficial across a range of environments? To answer these questions, we used two subsets (n = 18 and n = 63) of a large library of mutants carrying antibiotic resistance mutations in the bacterium Pseudomonas fluorescens whose fitness, along with the antibiotic sensitive ancestor, was assayed across 95 novel environments differing in the carbon source available for growth. We explore patterns of genotype-by-environment (G×E) interactions and ecological specialization among the 18 mutants initially found superior to the sensitive ancestor in one environment. We find that G×E is remarkably similar between the two sets of mutants and that beneficial mutants are not typically associated with large costs of adaptation. Fitness effects among beneficial mutants depart from a strict exponential distribution: they assume a variety of shapes that are often roughly L shaped but always right truncated. Distributions of (beneficial) fitness effects predicted by a landscape model assuming multiple traits underlying fitness and a single optimum often provide a good description of the empirical distributions in our data. Simulations of data sets containing a mixture of single and double mutants under this landscape show that inferences about the distribution of fitness effects of beneficial mutants is quite robust to contamination by second-site mutations. PMID:21868607

  2. Biosurfactant production by Pseudomonas fluorescens growing on molasses and its application in phenol degradation

    Science.gov (United States)

    Suryantia, Venty; Marliyana, Soerya Dewi; Wulandari, Astri

    2015-12-01

    A molasses based medium for the biosurfactant production by Pseudomonas fluorescens was developed, where the effect of pre-treated of molasses and medium composition were evaluated. Biosurfactant production was followed by measuring optical density (OD), surface tension and emulsifying index (E24) over 12 days of fermentation. The optimum condition for the biosurfactant production was obtained when a medium containing of 8 g/L nutrient broth, 5 g/L NaCl, 1 g/L NH4NO3 and 5% v/v pre-treated molasses with centrifugation was used as media with 3 days of fermentation. The biosurfactant was identified as a rhamnolipid type biosurfactant which had critical micelle concentration (CMC) value of 801 mg/L and was able to reduce the surface tension of the water from 80 mN/m to 51 mN/m. The biosurfactants had water in oil (w/o) emulsion type. Biosurfactant was able to emulsify various hydrocarbons, which were able to decrase the interfacial tension about 50-75% when benzyl chloride, anisaldehyde and palm oil were used as immiscible compounds. The biosurfactant exhibited the E24 value of about 50% and the stable emulsion was reached up to 30 days when lubricant was used as an immiscible compound. Up to 68% of phenol was degraded in the presence of biosurfactant within 15 days, whereas only 56% of phenol was degraded in the absence of biosurfactant. Overall, the results exhibited that molasses are recommended for the rhamnolipids production which possessed good surface-active properties and had potential application in the enhancement of phenol degradation.

  3. Chemotactic Motility of Pseudomonas fluorescens F113 under Aerobic and Denitrification Conditions.

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    Candela Muriel

    Full Text Available The sequence of the genome of Pseudomonas fluorescens F113 has shown the presence of multiple traits relevant for rhizosphere colonization and plant growth promotion. Among these traits are denitrification and chemotactic motility. Besides aerobic growth, F113 is able to grow anaerobically using nitrate and nitrite as final electron acceptors. F113 is able to perform swimming motility under aerobic conditions and under anaerobic conditions when nitrate is used as the electron acceptor. However, nitrite can not support swimming motility. Regulation of swimming motility is similar under aerobic and anaerobic conditions, since mutants that are hypermotile under aerobic conditions, such as gacS, sadB, kinB, algU and wspR, are also hypermotile under anaerobic conditions. However, chemotactic behavior is different under aerobic and denitrification conditions. Unlike most pseudomonads, the F113 genome encode three complete chemotaxis systems, Che1, Che2 and Che3. Mutations in each of the cheA genes of the three Che systems has shown that the three systems are functional and independent. Mutation of the cheA1 gene completely abolished swimming motility both under aerobic and denitrification conditions. Mutation of the cheA2 gene, showed only a decrease in swimming motility under both conditions, indicating that this system is not essential for chemotactic motility but is necessary for optimal motility. Mutation of the cheA3 gene abolished motility under denitrification conditions but only produced a decrease in motility under aerobic conditions. The three Che systems proved to be implicated in competitive rhizosphere colonization, being the cheA1 mutant the most affected.

  4. Extracellular Protease of Pseudomonas fluorescens CHA0, a Biocontrol Factor with Activity against the Root-Knot Nematode Meloidogyne incognita

    OpenAIRE

    Siddiqui, Imran Ali; Haas, Dieter; Heeb, Stephan

    2005-01-01

    In Pseudomonas fluorescens CHA0, mutation of the GacA-controlled aprA gene (encoding the major extracellular protease) or the gacA regulatory gene resulted in reduced biocontrol activity against the root-knot nematode Meloidogyne incognita during tomato and soybean infection. Culture supernatants of strain CHA0 inhibited egg hatching and induced mortality of M. incognita juveniles more strongly than did supernatants of aprA and gacA mutants, suggesting that AprA protease contributes to biocon...

  5. Estrategias de identificación de genes de proteasas en una cepa de pseudomonas fluorescens alterante de leche

    OpenAIRE

    Rodrigo Torres, Lidia

    2013-01-01

    La leche es un alimento muy completo nutricionalmente y por ello fácilmente alterable por microorganismos si no se adoptan unas medidas de higiene adecuadas. El análisis de un lote de leche esterilizada comercial alterada reveló la presencia de una cepa de Pseudomonas fluorescens con actividad proteolítica y lipolítica. El objetivo de este trabajo fue diseñar oligonucleótidos y utilizar la técnica de amplificación por PCR (Polymerase Chain Reaction), seguida de secuenciación o de clonación...

  6. Isolation and characterization of antimicrobial cyclic dipeptides from Pseudomonas fluorescens and their efficacy on sorghum grain mold fungi.

    Science.gov (United States)

    Sajeli Begum, Ahil; Basha, Shaik Ameer; Raghavendra, Govardhanam; Kumar, Mallela Venkata Nagesh; Singh, Yukthi; Patil, Jagannath V; Tanemura, Yuhei; Fujimoto, Yoshinori

    2014-01-01

    This study was aimed at isolation and characterization of natural antifungal compounds for grain mold, a key parasitic fungal disease of sorghum. Pseudomonas fluorescens strain isolated from rhizosphere of groundnut crop was selected as a source. Its biocontrolling ability was assessed by testing some biochemical attributes such as phosphate-solubilization, and HCN, NH3 , indole-3-acetic acid, and siderophore production. The strain showed positive result for all except indole-3-acetic acid, revealing its suitability for a further study. The antibiotic-sensitivity pattern of the strain against 43 antibiotics was also established, which showed resistance to 15 antibiotics. The efficacy of P. fluorescens strain against grain mold was identified by dual culture technique. Hundred percent inhibition was found against Fusarium moniliforme, an important causative agent of this disease. The strain was fermented for secondary metabolites and extracted with AcOEt. Chromatographic separation of the extract yielded four known compounds, cyclo(L-Pro-L-Phe) (1), cyclo(trans-4-hydroxy-L-Pro-L-Leu) (2), cyclo(trans-4-hydroxy-L-Pro-L-Phe) (3), and cyclo(Gly-L-Pro) (4), which were characterized by spectral analysis and optical rotation. The crude extract, a mixture of 2 and 3, and isolated 1 were proved to be significantly effective against grain mold fungi. This is the first report on production of these cyclic dipeptides by P. fluorescens and their antagonistic properties. Copyright © 2014 Verlag Helvetica Chimica Acta AG, Zürich.

  7. Pseudomonas fluorescens induces strain-dependent and strain-independent host plant responses in defense networks, primary metabolism and photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Pelletier, Dale A [ORNL; Morrell-Falvey, Jennifer L [ORNL; Karve, Abhijit A [ORNL; Lu, Tse-Yuan S [ORNL; Tschaplinski, Timothy J [ORNL; Tuskan, Gerald A [ORNL; Chen, Jay [ORNL; Martin, Madhavi Z [ORNL; Jawdy, Sara [ORNL; Weston, David [ORNL; Doktycz, Mitchel John [ORNL; Schadt, Christopher Warren [ORNL

    2012-01-01

    Colonization of plants by nonpathogenic Pseudomonas fluorescens strains can confer enhanced defense capacity against a broad spectrum of pathogens. Few studies, however, have linked defense pathway regulation to primary metabolism and physiology. In this study, physiological data, metabolites, and transcript profiles are integrated to elucidate how molecular networks initiated at the root-microbe interface influence shoot metabolism and whole-plant performance. Experiments with Arabidopsis thaliana were performed using the newly identified P. fluorescens GM30 or P. fluorescens Pf-5 strains. Co-expression networks indicated that Pf-5 and GM30 induced a subnetwork specific to roots enriched for genes participating in RNA regulation, protein degradation, and hormonal metabolism. In contrast, only GM30 induced a subnetwork enriched for calcium signaling, sugar and nutrient signaling, and auxin metabolism, suggesting strain dependence in network architecture. In addition, one subnetwork present in shoots was enriched for genes in secondary metabolism, photosynthetic light reactions, and hormone metabolism. Metabolite analysis indicated that this network initiated changes in carbohydrate and amino acid metabolism. Consistent with this, we observed strain-specific responses in tryptophan and phenylalanine abundance. Both strains reduced host plant carbon gain and fitness, yet provided a clear fitness benefit when plants were challenged with the pathogen P. syringae DC3000.

  8. Pseudomonas fluorescens filamentous hemagglutinin, an iron-regulated protein, is an important virulence factor that modulates bacterial pathogenicity

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    Yuan-yuan Sun

    2016-08-01

    Full Text Available Pseudomonas fluorescens is a common bacterial pathogen to a wide range of aquaculture animals including various species of fish. In this study, we employed proteomic analysis and identified filamentous hemagglutinin (FHA as an iron-responsive protein secreted by TSS, a pathogenic P. fluorescens isolate. In vitro study showed that compared to the wild type, the fha mutant TSSfha (i exhibited a largely similar vegetative growth profile but significantly retarded in the ability of biofilm growth and producing extracellular matrix, (ii displayed no apparent flagella and motility, (iii was defective in the attachment to host cells and unable to form self-aggregation, (iv displayed markedly reduced capacity of hemagglutination and surviving in host serum. In vivo infection analysis revealed that TSSfha was significantly attenuated in the ability of dissemination in fish tissues and inducing host mortality, and that antibody blocking of the natural FHA produced by the wild type TSS impaired the infectivity of the pathogen. Furthermore, when introduced into turbot as a subunit vaccine, recombinant FHA elicited a significant protection against lethal TSS challenge. Taken together, these results indicate for the first time that P. fluorescens FHA is a key virulence factor essential to multiple biological processes associated with pathogenicity.

  9. Listeria monocytogenes Impact on Mature or Old Pseudomonas fluorescens Biofilms During Growth at 4 and 20°C.

    Science.gov (United States)

    Puga, Carmen H; Orgaz, Belen; SanJose, Carmen

    2016-01-01

    Changes in spatial organization, as observed by confocal laser scanning microscopy (CLSM), viable cell content, biovolume, and substratum surface coverage of the biofilms formed on glass by Pseudomonas fluorescens resulting from co-culture with Listeria monocytogenes, were examined. Two strains of L. monocytogenes, two culture temperatures and two biofilm developmental stages were investigated. Both L. monocytogenes strains, a persistently sampled isolate (collected repeatedly along 3 years from a meat factory) and Scott A, induced shrinkage in matrix volume, both at 20°C and 4°C, in mature or old biofilms, without loss of P. fluorescens cell count per surface unit. The nearly homogeneous pattern of surface coverage shown by mono-species P. fluorescens biofilms, turned into more irregular layouts in co-culture with L. monocytogenes. The upper layer of both mono and dual-species biofilms turned to predominantly consist of matrix, with plenty of viable cells underneath, in old biofilms cultured at 20°C, but not in those grown at 4°C. Between 15 and 56% of the substratum area was covered by biofilm, the extent depending on temperature, time and L. monocytogenes strain. Real biofilms in food-related surfaces may thus be very heterogeneous regarding their superficial components, i.e., those more accessible to disinfectants. It is therefore a hygienic challenge to choose an adequate agent to disrupt them.

  10. Phytohormone production and colonization of canola (Brassica napus L.) roots by Pseudomonas fluorescens 6-8 under gnotobiotic conditions.

    Science.gov (United States)

    Pallai, Rajash; Hynes, Russell K; Verma, Brij; Nelson, Louise M

    2012-02-01

    Pseudomonas fluorescens 6-8, a rhizosphere isolate previously shown to enhance root elongation of canola ( Brassica napus L.), was characterized for its ability to produce indole-3-acetic acid and cytokinins in pure culture and in the rhizosphere of canola under gnotobiotic conditions in comparison with the cytokinin-producing strain P. fluorescens G20-18 and its mutant CNT2. Strain 6-8 produced isopentenyl adenosine, zeatin riboside, and dihydroxyzeatin riboside at levels similar to those of G20-18, but only very low concentrations of indole-3-acetic acid. In a gnotobiotic assay canola inoculated with 6-8 and G20-18 had higher concentrations of isopentenyl adenosine and zeatin riboside in the rhizosphere and greater root length than the noninoculated control. The ability of strain 6-8 to colonize canola roots was assessed following transformation with the green fluorescent protein and inoculation onto canola seed in a gnotobiotic assay. Higher populations of strain 6-8 were observed on the proximal region of the root closest to the seed than on the mid and distal portions 9 days after seed inoculation. The ability of P. fluorescens 6-8 to produce cytokinins, colonize the roots of canola seedlings, and enhance root elongation may contribute to its ability to survive in the rhizosphere and may benefit seedling growth.

  11. On the role of metabolic activity on the transport und deposition of Pseudomonas fluorescens in saturated porous media.

    Science.gov (United States)

    Jansen, Sandra; Vereecken, Harry; Klumpp, Erwin

    2010-02-01

    A study was conducted to understand the role of cell concentration and metabolic state in the transport and deposition behaviour of Pseudomonas fluorescens with and without substrate addition. Column experiments using the short-pulse technique (pulse was equivalent to 0.028 pore volume) were performed in quartz sand operating under saturated conditions. For comparison, experiments with microspheres and inactive (killed) bacteria were also conducted. The effluent concentrations, the retained particle concentrations and the cell shape were determined by fluorescent microscopy. For the transport of metabolically-active P. fluorescens without substrate addition a bimodal breakthrough curve was observed, which could be explained by the different breakthrough behaviour of the rod-shaped and coccoidal cells of P. fluorescens. The 70:30 rod/coccoid ratio in the influent drastically changed during the transport and it was about 20:80 in the effluent and in the quartz sand packing. It was assumed that the active rod-shaped cells were subjected to shrinkage into coccoidal cells. The change from active rod-shaped cells to coccoidal cells could be explained by oxygen deficiency which occurs in column experiments under saturated conditions. Also the substrate addition led to two consecutive breakthrough peaks and to more bacteria being retained in the column. In general, the presence of substrate made the assumed stress effects more pronounced. In comparison to microspheres and inactive (killed) bacteria, the transport of metabolically-active bacteria with and without substrate addition is affected by differences in physiological state between rod-shaped and the formed stress-resistant coccoidal cells of P. fluorescens. Copyright 2010 Elsevier Ltd. All rights reserved.

  12. Cloning and expression of Pseudomonas fluorescens 26-2 lipase gene in Pichia pastoris and characterizing for transesterification.

    Science.gov (United States)

    Yang, Jiangke; Zhang, Bo; Yan, Yunjun

    2009-11-01

    Pseudomonas lipases are important biocatalysts widely used in a variety of industrial fields. An extracellular lipase gene lipA with 1,854-bp open reading frame was cloned from Pseudomonas fluorescens 26-2. The multialignment assay of the putative amino acid and the secondary structure prediction revealed this enzyme could be classified into the lipolytic subfamily I.3 and secreted via adenosine-triphosphate-binding cassette pathway. The lipA gene was integrated into Pichia pastoris GS115, and the methanol-inducible recombinants with Mut(S) and Mut(+) phenotypes were acquired. The characteristics and the transesterification capacity shown by this enzyme suggested it is a useful biocatalyst for biodiesel preparation.

  13. Identification of anthranilate and benzoate metabolic operons of Pseudomonas fluorescens and functional characterization of their promoter regions

    Directory of Open Access Journals (Sweden)

    Lee Vincent D

    2006-01-01

    Full Text Available Abstract Background In an effort to identify alternate recombinant gene expression systems in Pseudomonas fluorescens, we identified genes encoding two native metabolic pathways that were inducible with inexpensive compounds: the anthranilate operon (antABC and the benzoate operon (benABCD. Results The antABC and benABCD operons were identified by homology to the Acinetobacter sp. anthranilate operon and Pseudomonas putida benzoate operon, and were confirmed to be regulated by anthranilate or benzoate, respectively. Fusions of the putative promoter regions to the E. coli lacZ gene were constructed to confirm inducible gene expression. Each operon was found to be controlled by an AraC family transcriptional activator, located immediately upstream of the first structural gene in each respective operon (antR or benR. Conclusion We have found the anthranilate and benzoate promoters to be useful for tightly controlling recombinant gene expression at both small (

  14. Legionella pneumophila persists within biofilms formed by Klebsiella pneumoniae, Flavobacterium sp., and Pseudomonas fluorescens under dynamic flow conditions.

    Directory of Open Access Journals (Sweden)

    Catherine R Stewart

    Full Text Available Legionella pneumophila, the agent of Legionnaires' disease pneumonia, is transmitted to humans following the inhalation of contaminated water droplets. In aquatic systems, L. pneumophila survives much of time within multi-organismal biofilms. Therefore, we examined the ability of L. pneumophila (clinical isolate 130 b to persist within biofilms formed by various types of aquatic bacteria, using a bioreactor with flow, steel surfaces, and low-nutrient conditions. L. pneumophila was able to intercalate into and persist within a biofilm formed by Klebsiella pneumoniae, Flavobacterium sp. or Pseudomonas fluorescens. The levels of L. pneumophila within these biofilms were as much as 4 × 10(4 CFU per cm(2 of steel coupon and lasted for at least 12 days. These data document that K. pneumoniae, Flavobacterium sp., and P. fluorescens can promote the presence of L. pneumophila in dynamic biofilms. In contrast to these results, L. pneumophila 130 b did not persist within a biofilm formed by Pseudomonas aeruginosa, confirming that some bacteria are permissive for Legionella colonization whereas others are antagonistic. In addition to colonizing certain mono-species biofilms, L. pneumophila 130 b persisted within a two-species biofilm formed by K. pneumoniae and Flavobacterium sp. Interestingly, the legionellae were also able to colonize a two-species biofilm formed by K. pneumoniae and P. aeruginosa, demonstrating that a species that is permissive for L. pneumophila can override the inhibitory effect(s of a non-permissive species.

  15. Mutation rate, spectrum, topology, and context-dependency in the DNA mismatch repair-deficient Pseudomonas fluorescens ATCC948.

    Science.gov (United States)

    Long, Hongan; Sung, Way; Miller, Samuel F; Ackerman, Matthew S; Doak, Thomas G; Lynch, Michael

    2014-12-23

    High levels of genetic diversity exist among natural isolates of the bacterium Pseudomonas fluorescens, and are especially elevated around the replication terminus of the genome, where strain-specific genes are found. In an effort to understand the role of genetic variation in the evolution of Pseudomonas, we analyzed 31,106 base substitutions from 45 mutation accumulation lines of P. fluorescens ATCC948, naturally deficient for mismatch repair, yielding a base-substitution mutation rate of 2.34 × 10(-8) per site per generation (SE: 0.01 × 10(-8)) and a small-insertion-deletion mutation rate of 1.65 × 10(-9) per site per generation (SE: 0.03 × 10(-9)). We find that the spectrum of mutations in prophage regions, which often contain virulence factors and antibiotic resistance, is highly similar to that in the intergenic regions of the host genome. Our results show that the mutation rate varies around the chromosome, with the lowest mutation rate found near the origin of replication. Consistent with observations from other studies, we find that site-specific mutation rates are heavily influenced by the immediately flanking nucleotides, indicating that mutations are context dependent. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  16. Synthesis of silver nanoparticles by endosymbiont Pseudomonas fluorescens CA 417 and their bactericidal activity.

    Science.gov (United States)

    Syed, Baker; M N, Nagendra Prasad; B L, Dhananjaya; K, Mohan Kumar; S, Yallappa; S, Satish

    2016-12-01

    The present study emphasizes on biogenic synthesis of silver nanoparticles and their bactericidal activity against human and phytopathogens. Nanoparticle synthesis was performed using endosymbiont Pseudomonas fluorescens CA 417 inhabiting Coffea arabica L. Synthesized nanoparticles were characterized using hyphenated spectroscopic techniques such as UV-vis spectroscopy which revealed maximum absorption 425nm. Fourier transform infrared spectroscopy (FTIR) analysis revealed the possible functional groups mediating and stabilizing silver nanoparticles with predominant peaks occurring at 3346 corresponding to hydroxyl group, 1635 corresponding carbonyl group and 680 to aromatic group. X-ray diffraction (XRD) analysis revealed the Bragg's diffraction pattern with distinct peaks at 38° 44°, 64° and 78° revealing the face-centered cubic (fcc) metallic crystal corresponding to the (111), (200), (220) and (311) facets of the crystal planes at 2θ angle. The energy dispersive X-ray spectroscopy (EDS) analysis revealed presence of high intense absorption peak at 3keV is a typical characteristic of nano-crystalline silver which confirmed the presence of elemental silver. TEM analysis revealed the size of the nanoparticles to be in the range 5-50nm with polydisperse nature of synthesized nanoparticles bearing myriad shapes. The particle size determined by Dynamic light scattering (DLS) method revealed average size to be 20.66nm. The synthesized silver nanoparticles exhibited significant antibacterial activity against panel of test pathogens. The results showed Klebsiella pneumoniae (MTCC 7407) and Xanthomonas campestris to be more sensitive among the test human pathogen and phyto-pathogen respectively. The study also reports synergistic effect of silver nanoparticles in combination with kanamycin which displayed increased fold activity up to 58.3% against Klebsiella pneumoniae (MTCC 7407). The results of the present investigation are promising enough and attribute towards

  17. Structure Revision of N-Mercapto-4-formylcarbostyril Produced by Pseudomonas fluorescens G308 to 2-(2-Hydroxyphenyl)thiazole-4-carbaldehyde [aeruginaldehyde

    DEFF Research Database (Denmark)

    Guillemyn, Karel; Ballet, Steven; Ye, Lumeng

    2014-01-01

    An antibiotic substance isolated from Pseudomonas fluorescens strain G308 was earlier assigned the structure of N-mercapto-4-formylcarbostyril, but computational predictions of the H-1 and C-13 NMR magnetic shielding tensors show this structure to be incompatible with the published spectroscopic...

  18. Draft Genome Sequences of Pseudomonas fluorescens BS2 and Pusillimonas noertemannii BS8, Soil Bacteria That Cooperate To Degrade the Poly- -D-Glutamic Acid Anthrax Capsule

    KAUST Repository

    Stabler, R. A.

    2013-01-24

    A mixed culture of Pseudomonas fluorescens BS2 and Pusillimonas noertemannii BS8 degraded poly-γ-d-glutamic acid; when the 2 strains were cultured separately, no hydrolytic activity was apparent. Here we report the draft genome sequences of both soil isolates.

  19. Expression of Fap amyloids in Pseudomonas aeruginosa, P. fluorescens, and P. putida results in aggregation and increased biofilm formation

    DEFF Research Database (Denmark)

    Dueholm, Morten S; Søndergaard, Mads; Nilsson, Martin

    2013-01-01

    The fap operon, encoding functional amyloids in Pseudomonas (Fap), is present in most pseudomonads, but so far the expression and importance for biofilm formation has only been investigated for P. fluorescens strain UK4. In this study, we demonstrate the capacity of P. aeruginosa PAO1, P. fluores...

  20. Saccharomyces cerevisiae genome-wide mutant screen for sensitivity to 2,4-diacetylphloroglucinol, a biocontrol antibiotic produced by Pseudomonas fluorescens

    Science.gov (United States)

    2,4-diacetylphloroglucinol (2,4-DAPG) is an antibiotic produced by Pseudomonas fluorescens that plays a key role in the ability of the bacterium to suppress phytopathogenic fungi. 2,4-DAPG has broad antibiotic activity, affecting organisms ranging from bacteria to higher plants. The biosynthesis and...

  1. Elucidation of the Vibrio anguillarum genetic response to the potential fish probiont Pseudomonas fluorescens AH2, using RNA-arbitrarily primed PCR

    DEFF Research Database (Denmark)

    Holmstrøm, Kim; Gram, Lone

    2003-01-01

    The antagonistic interaction between a potential fish probiont, Pseudomonas fluorescens strain AH2, and its target organism, Vibrio anguillarum, was investigated by studying the genetic response of the target organism when it was exposed to the antagonist. We compared the differential display of ......, which results in instant iron deprivation of the pathogen V. anguillarum and complete growth arrest....

  2. The Rsm regulon of plant growth-promoting Pseudomonas fluorescens SS101: role of small RNAs in regulation of lipopeptide biosynthesis

    NARCIS (Netherlands)

    Song, C.; Voort, van der M.; Mortel, van de J.; Hassan, K.A.; Elbourne, L.D.H.; Paulsen, I.T.; Loper, J.E.; Raaijmakers, J.M.

    2015-01-01

    The rhizobacterium Pseudomonas fluorescens SS101 inhibits growth of oomycete and fungal pathogens, and induces resistance in plants against pathogens and insects. To unravel regulatory pathways of secondary metabolite production in SS101, we conducted a genome-wide search for sRNAs and performed

  3. New insights into Pseudomonas fluorescens alginate biosynthesis relevant for the establishment of an efficient production process for microbial alginates.

    Science.gov (United States)

    Maleki, Susan; Mærk, Mali; Hrudikova, Radka; Valla, Svein; Ertesvåg, Helga

    2017-07-25

    Alginate denotes a family of linear polysaccharides with a wide range of industrial and pharmaceutical applications. Presently, all commercially available alginates are manufactured from brown algae. However, bacterial alginates have advantages with regard to compositional homogeneity and reproducibility. In order to be able to design bacterial strains that are better suited for industrial alginate production, defining limiting factors for alginate biosynthesis is of vital importance. Our group has been studying alginate biosynthesis in Pseudomonas fluorescens using several complementary approaches. Alginate is synthesised and transported out of the cell by a multiprotein complex spanning from the inner to the outer membrane. We have developed an immunogold labelling procedure in which the porin AlgE, as a part of this alginate factory, could be detected by transmission electron microscopy. No time-dependent correlation between the number of such factories on the cell surface and alginate production level was found in alginate-producing strains. Alginate biosynthesis competes with the central carbon metabolism for the key metabolite fructose 6-phosphate. In P. fluorescens, glucose, fructose and glycerol, are metabolised via the Entner-Doudoroff and pentose phosphate pathways. Mutational analysis revealed that disruption of the glucose 6-phosphate dehydrogenase gene zwf-1 resulted in increased alginate production when glycerol was used as carbon source. Furthermore, alginate-producing P. fluorescens strains cultivated on glucose experience acid stress due to the simultaneous production of alginate and gluconate. The combined results from our studies strongly indicate that the availability of fructose 6-phosphate and energy requires more attention in further research aimed at the development of an optimised alginate production process. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Susceptibility of Mycobacterium immunogenum and Pseudomonas fluorescens to formaldehyde and non-formaldehyde biocides in semi-synthetic metalworking fluids.

    Science.gov (United States)

    Selvaraju, Suresh B; Khan, Izhar U H; Yadav, Jagjit S

    2011-01-20

    Mycobacterium immunogenum, a newly identified member of the Mycobacterium chelonae_M. abscessus complex is considered a potential etiological agent for hypersensitivity pneumonitis (HP) in machine workers exposed to contaminated metalworking fluid (MWF). This study investigated the biocidal efficacy of the frequently applied commercial formaldehyde-releasing (HCHO) biocides Grotan and Bioban CS 1135 and non-HCHO type biocides Kathon 886 MW (isothiazolone) and Preventol CMK 40 (phenolic) toward this emerging mycobacterial species (M. immunogenum) in HP-linked MWFs, alone and in presence of a representative of the Gram-negative bacterial contaminants, Pseudomonas fluorescens, using two semi-synthetic MWF matrices (designated Fluid A and Fluid B). Relative biocide susceptibility analysis indicated M immunogenum to be comparatively more resistant (2-1600 fold) than P. fluorescens to the tested biocides under the varied test conditions. In terms of minimum inhibitory concentration, Kathon was the most effective biocide against M. immunogenum. Fluid factors had a major effect on the biocide susceptibility. Fluid A formulation provided greater protective advantage to the test organisms than Fluid B. Fluid dialysis (Fluid A) led to an increased biocidal efficacy of Grotan, Kathon and Preventol against M. immunogenum further implying the role of native fluid components. Used fluid matrix, in general, increased the resistance of the two test organisms against the biocides, with certain exceptions. M. immunogenum resistance increased in presence of the co-contaminant P. fluorescens. Collectively, the results show a multifactorial nature of the biocide susceptibility of MWF-colonizing mycobacteria and highlight the importance of more rigorous efficacy testing and validation of biocides prior to and during their application in metalworking fluid operations.

  5. Susceptibility of Mycobacterium immunogenum and Pseudomonas fluorescens to Formaldehyde and Non-Formaldehyde Biocides in Semi-Synthetic Metalworking Fluids

    Directory of Open Access Journals (Sweden)

    Suresh B. Selvaraju

    2011-01-01

    Full Text Available Mycobacterium immunogenum, a newly identified member of the Mycobacterium chelonae_M. abscessus complex is considered a potential etiological agent for hypersensitivity pneumonitis (HP in machine workers exposed to contaminated metalworking fluid (MWF. This study investigated the biocidal efficacy of the frequently applied commercial formaldehyde-releasing (HCHO biocides Grotan and Bioban CS 1135 and non-HCHO type biocides Kathon 886 MW (isothiazolone and Preventol CMK 40 (phenolic toward this emerging mycobacterial species (M. immunogenum in HP-linked MWFs, alone and in presence of a representative of the Gram-negative bacterial contaminants, Pseudomonas fluorescens, using two semi-synthetic MWF matrices (designated Fluid A and Fluid B. Relative biocide susceptibility analysis indicated M immunogenum to be comparatively more resistant (2–1600 fold than P. fluorescens to the tested biocides under the varied test conditions. In terms of minimum inhibitory concentration, Kathon was the most effective biocide against M. immunogenum. Fluid factors had a major effect on the biocide susceptibility. Fluid A formulation provided greater protective advantage to the test organisms than Fluid B. Fluid dialysis (Fluid A led to an increased biocidal efficacy of Grotan, Kathon and Preventol against M. immunogenum further implying the role of native fluid components. Used fluid matrix, in general, increased the resistance of the two test organisms against the biocides, with certain exceptions. M. immunogenum resistance increased in presence of the co-contaminant P. fluorescens. Collectively, the results show a multifactorial nature of the biocide susceptibility of MWF-colonizing mycobacteria and highlight the importance of more rigorous efficacy testing and validation of biocides prior to and during their application in metalworking fluid operations.

  6. Enhanced citric acid biosynthesis in Pseudomonas fluorescens ATCC 13525 by overexpression of the Escherichia coli citrate synthase gene.

    Science.gov (United States)

    Buch, Aditi D; Archana, G; Kumar, G Naresh

    2009-08-01

    Citric acid secretion by fluorescent pseudomonads has a distinct significance in microbial phosphate solubilization. The role of citrate synthase in citric acid biosynthesis and glucose catabolism in pseudomonads was investigated by overexpressing the Escherichia coli citrate synthase (gltA) gene in Pseudomonas fluorescens ATCC 13525. The resultant approximately 2-fold increase in citrate synthase activity in the gltA-overexpressing strain Pf(pAB7) enhanced the intracellular and extracellular citric acid yields during the stationary phase, by about 2- and 26-fold, respectively, as compared to the control, without affecting the growth rate, glucose depletion rate or biomass yield. Decreased glucose consumption was paralleled by increased gluconic acid production due to an increase in glucose dehydrogenase activity. While the extracellular acetic acid yield increased in Pf(pAB7), pyruvic acid secretion decreased, correlating with an increase in pyruvate carboxylase activity and suggesting an increased demand for the anabolic precursor oxaloacetate. Activities of two other key enzymes, glucose-6-phosphate dehydrogenase and isocitrate dehydrogenase, remained unaltered, and the contribution of phosphoenolpyruvate carboxylase and isocitrate lyase to glucose catabolism was negligible. Strain Pf(pAB7) demonstrated an enhanced phosphate-solubilizing ability compared to the control. Co-expression of the Synechococcus elongatus PCC 6301 phosphoenolpyruvate carboxylase and E. coli gltA genes in P. fluorescens ATCC 13525, so as to supplement oxaloacetate for citrate biosynthesis, neither significantly affected citrate biosynthesis nor caused any change in the other physiological and biochemical parameters measured, despite approximately 1.3- and 5-fold increases in citrate synthase and phosphoenolpyruvate carboxylase activities, respectively. Thus, our results demonstrate that citrate synthase is rate-limiting in enhancing citrate biosynthesis in P. fluorescens ATCC 13525

  7. Photocatalytic disinfection of spoilage bacteria Pseudomonas fluorescens and Macrococcus caseolyticus by nano-TiO2

    Science.gov (United States)

    Photocatalytic disinfection of spoilage bacteria gram-negative (G-) P. fluorescens and gram-positive (G+) M. caseolyticus by nano-TiO2 under different experimental conditions and the disinfection mechanism were investigated. The experimental conditions included the initial bacterial populations, nan...

  8. Whole-genome sequence of Pseudomonas fluorescens EK007-RG4, a promising biocontrol agent against a broad range of bacteria, including the fire blight bacterium Erwinia amylovora

    DEFF Research Database (Denmark)

    Habibi, Roghayeh; Tarighi, Saeed; Behravan, Javad

    2017-01-01

    Here, we report the first draft whole-genome sequence of Pseudomonas fluorescens strain EK007-RG4, which was isolated from the phylloplane of a pear tree. P. fluorescens EK007-RG4 displays strong antagonism against Erwinia amylovora, the causal agent for fire blight disease, in addition to several...

  9. Mycorrhization between Cistus ladanifer L. and Boletus edulis Bull is enhanced by the mycorrhiza helper bacteria Pseudomonas fluorescens Migula.

    Science.gov (United States)

    Mediavilla, Olaya; Olaizola, Jaime; Santos-del-Blanco, Luis; Oria-de-Rueda, Juan Andrés; Martín-Pinto, Pablo

    2016-02-01

    Boletus edulis Bull. is one of the most economically and gastronomically valuable fungi worldwide. Sporocarp production normally occurs when symbiotically associated with a number of tree species in stands over 40 years old, but it has also been reported in 3-year-old Cistus ladanifer L. shrubs. Efforts toward the domestication of B. edulis have thus focused on successfully generating C. ladanifer seedlings associated with B. edulis under controlled conditions. Microorganisms have an important role mediating mycorrhizal symbiosis, such as some bacteria species which enhance mycorrhiza formation (mycorrhiza helper bacteria). Thus, in this study, we explored the effect that mycorrhiza helper bacteria have on the efficiency and intensity of the ectomycorrhizal symbiosis between C. ladanifer and B. edulis. The aim of this work was to optimize an in vitro protocol for the mycorrhizal synthesis of B. edulis with C. ladanifer by testing the effects of fungal culture time and coinoculation with the helper bacteria Pseudomonas fluorescens Migula. The results confirmed successful mycorrhizal synthesis between C. ladanifer and B. edulis. Coinoculation of B. edulis with P. fluorescens doubled within-plant mycorrhization levels although it did not result in an increased number of seedlings colonized with B. edulis mycorrhizae. B. edulis mycelium culture time also increased mycorrhization levels but not the presence of mycorrhizae. These findings bring us closer to controlled B. edulis sporocarp production in plantations.

  10. The use of Pseudomonas fluorescens P13 to control sclerotinia stem rot (Sclerotinia sclerotiorum) of oilseed rape.

    Science.gov (United States)

    Li, Hui; Li, Huaibo; Bai, Yan; Wang, Jing; Nie, Ming; Li, Bo; Xiao, Ming

    2011-12-01

    Sclerotinia stem rot (SSR) caused by the fungus Sclerotinia sclerotiorum has been an increasing threat to oilseed rape (Brassica napus L.) cultivation. Efficient and environment-friendly treatments are much needed. Here we focus on microbial control. The Pseudomonas fluorescens P13 that was isolated from oilseed rape cultivation soil, proved to be a useful biocontrol strain for application. Morphology, physiological and biochemical tests and 16S rDNA analysis demonstrated that it was P. fluorescens P13 and that it had a broad antagonistic spectrum, significantly lessening the mycelial growth of S. sclerotiorum by 84.4% and suppressing sclerotial formation by 95-100%. Scanning electron microscopy studies attested that P13 deformed S. sclerotiorum mycelia when they were cultured together. P13 did not produce chitinase but did produce hydrogen cyanide (HCN) which was likely one of the antagonistic mechanisms. The density of P13 remained at a high level (≥10(6) CFU/ml) during 5 weeks in the rhizosphere soil and roots. P13 reduced SSR severity at least by 59% in field studies and also promoted seedling growth (psclerotiorum.

  11. 1-aminocyclopropane-1-carboxylate deaminase from Pseudomonas fluorescens promoting the growth of Chinese cabbage and its polyclonal antibody.

    Science.gov (United States)

    Soh, Byoung Yul; Lee, Gun Woong; Go, Eun Byeul; Kim, Byeo-Ri; Lee, Kui-Jae; Chae, Jong-Chan

    2014-05-01

    Bacterial 1-aminocyclopropane-1-carboxlyate (ACC) deaminase (AcdS) is an enzyme that cleaves ACC, a precursor of the plant hormone ethylene, into α-ketobutyrate and ammonia. The acdS gene was cloned from Pseudomonas fluorescens, which was capable of improving the seedling of Chinese cabbage under salinity condition. The recombinant AcdS (rAcdS) exhibited optimal activity at pH 8.5 and 30°C. Strong activity was sustained at up to 100 mM NaCl. The polyclonal anti-P. fluorescens AcdS antibody was produced in a rabbit that had been immunized with the purified rAcdS. This antibody successfully recognized the homologous antigens derived from the total proteins of isolated plant growth-promoting microorganisms. A statistically significant correlation was observed between the intensity of hybridization signal and AcdS activity measured by a biochemical method, suggesting its application as a useful indicator for active deaminases.

  12. Exposure-related effects of Pseudomonas fluorescens, strain CL145A, on coldwater, coolwater, and warmwater fish

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Denise A. Mayer,

    2015-01-01

    The exposure-related effects of a commercially prepared spray-dried powder (SDP) formulation of Pseudomonas fluorescens, strain CL145A, were evaluated on coldwater, coolwater, and warmwater fish endemic to the Great Lakes and Upper Mississippi River Basins. Nine species of young-of-the-year fish were exposed to SDP for 24 hours by using continuous-flow, serial-dilution exposure systems at temperatures of 12 degrees Celsius (°C; 2 species; Oncorhynchus mykiss [rainbow trout] and Salvelinus fontinalis [brook trout]), 17 °C (3 species; Perca flavescens [yellow perch], Sander vitreus [walleye], and Acipenser fulvescens [lake sturgeon]), or 22 °C (4 species; Micropterus salmoides [largemouth bass], Micropterus dolomieu [smallmouth bass], Lepomis macrochirus [bluegill sunfish], and Ictalurus punctatus [channel catfish]).

  13. Influence of phenolic acids on indole acetic acid production and on the type III secretion system gene transcription in food-associated Pseudomonas fluorescens KM05.

    Science.gov (United States)

    Myszka, Kamila; Schmidt, Marcin T; Olejnik-Schmidt, Agnieszka K; Leja, Katarzyna; Czaczyk, Katarzyna

    2014-12-01

    The purpose of these investigations was to evaluate the reduction capability of phenolic acids (ferulic, chlorogenic, gallic, and p-coumaric acids) on indole acetic acid synthesis by food-associated Pseudomonas fluorescens KM05. Specific genetic primer for the type III secretion system (TTSS) in P. fluorescens KM05 was designed and the influence of phenolic acids on its expression was investigated. In the work the ferulic and chlorogenic acids at the concentration of 0.02 and 0.04 μg/ml affected on bacterial growth pattern and the signal molecules production. The phenolic acids, that were appreciable effective against P. fluorescens KM05 indole acetic acid production, significantly suppressed TTSS gene. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  14. Effect of Pseudomonas fluorescens RB4 and Bacillus subtilis 189 on the phytoremediation potential of Catharanthus roseus (L.) in Cu and Pb-contaminated soils.

    Science.gov (United States)

    Khan, Waheed Ullah; Ahmad, Sajid Rashid; Yasin, Nasim Ahmad; Ali, Aamir; Ahmad, Aqeel

    2017-06-03

    The remediation of heavy metal-contaminated soils has become a critical issue due to toxic effects of these metals on living organisms. The current research was conducted to study the effect of Pseudomonas fluorescens RB4 and Bacillus subtilis 189 on the growth and phytoremediation potential of Catharanthus roseus in Cu- and Pb-contaminated soils. The bacterial strains exhibited significantly higher level of water-extractable Pb and Cu in Pb, Cu, and Cu+Pb-contaminated. The P. fluorescens RB4 inoculated plants, produced 102%, 48%, and 45% higher fresh weight (FW) in soils contaminated with Cu, Pb, and both elements, respectively, as compared to un-inoculated control plants. Similarly, B. subtilis 189 inoculated plants produced 108%, 43%, and 114% more FW in the presence of Cu, Pb, and both elements. The plants co-cultivated with both bacteria exhibited 121%, 102%, and 177% higher FW, in Cu, Pb, and both elements contaminated soils, as compared to respective un-inoculated control. Co-cultivation of P. fluorescens RB4, B. subtilis 189, and P. fluorescens RB4 + B. subtilis 189 resulted in higher accumulation of Cu and Pb in shoots of the C. roseus grown in contaminated soils as compared to un-inoculated control. Bacterial treatments also improved the translocation and metal bioconcentration factors. The growth and phytoextraction capability of C. roseus was improved by inoculation of P. fluorescens RB4 and B. subtilis 189.

  15. Biocontrol strain Pseudomonas fluorescens WCS365 inhibits germination of Fusarium oxysporum spores in tomato root exudate as well as subsequent formation of new spores.

    Science.gov (United States)

    Kamilova, Faina; Lamers, Gerda; Lugtenberg, Ben

    2008-09-01

    Fusarium oxysporum f.sp.radicis-licopersici (Forl) is a soilborne pathogenic fungus which can cause tomato foot and root rot (TFRR). Tomato root exudate is a good source of nutrients for both Forl and the TFRR-suppressing biocontrol bacterium Pseudomonas fluorescens strain WCS365. Incubation of Forl microconidia in tomato root exudate stimulates their germination. This phenomenon is observed, to a lesser extent, upon incubation in plant nutrient solution supplemented with citrate or glucose, the major organic acid and sugar components, respectively, of tomato root exudate. Here we show that induction of germination of microconidia is significantly reduced in the presence of P. fluorescens WCS365 in all tested media. Scanning electron microscopy revealed that P. fluorescens WCS365 colonizes developing hyphae. Efficient colonization correlates with low nutrient availability. Eventually, new microconidia are formed. The presence of P. fluorescens WCS365 reduces the number of newly formed microconidia. This reduction does not depend on physical contact between bacteria and hyphae. We discuss that the ability of P. fluorescens WCS365 to slow down the processes of microconidia germination and development of new microconidia of the phytopathogen, and therefore the ability to reduce fungal dissemination, is likely to contribute to the biocontrol efficacy of this strain.

  16. Effects of phosphorus fertilizer rate and Pseudomonas fluorescens strain on field pea (Pisum sativum subsp. arvense (L. Asch. growth and yield

    Directory of Open Access Journals (Sweden)

    Bahram SALEHI

    2015-11-01

    Full Text Available A field experiment was conducted at Rezvanshahr, Guilan province, Iran, to evaluate the effects of phosphorus fertilizer rate and Pseudomonas fluorescens strains on growth and yield of field pea (Pisum sativum L.. The experimental design was a randomized complete block in a factorial arrangement with three replicates. Factors were phosphorus fertilizer rates (0, 25, 50, 75, and 100 kg P2O5 ha-1 as triple superphosphate, and seed inoculation with P. florescens strains [control (non-inoculated, inoculated with strain R41, and strain R187. Analysis of variance showed that plant height, seed yield, pod number per m2, 100-seed weight, biological yield, harvest index, and leaf P concentration were significantly influenced by phosphorus fertilizer rate and P. florescens strain. At the same time, phosphorus fertilizer rate × P. fluorescens strain interaction was significant only for 100-seed weight. On the other hand, seed number per pod was significantly affected neither by phosphorus fertilizer rate nor by pseudomonas strains. Result showed that seed yield was significantly increased from 1099 ± 67 to 1898 ± 118 kg ha-1 as P2O5 application rate increased from 0 to 75 kg ha-1, and thereafter relatively remained constant. There was no significant difference in seed yield between plants raised from inoculated seeds with P. fluorescens, strain R187 (1664 ± 97 kg ha-1 and those raised from inoculated seeds with P. fluorescens, strain R41 (1669 ± 104 kg ha-1. At the same time, plants raised from inoculated seeds with P. fluorescens (both strains produced greater grain yield compared to those raised from uninoculated seeds (1370 ± 80 kg ha-1. Based on the results of this study, P2O5 application at the rate of 75 kg ha-1 and inoculation with pseudomonas bacteria are recommended for obtaining the greatest seed yield in field pea.

  17. Combined inoculation of Pseudomonas fluorescens and Trichoderma harzianum for enhancing plant growth of vanilla (Vanilla planifolia)

    National Research Council Canada - National Science Library

    Sandheep, A R; Asok, A K; Jisha, M S

    2013-01-01

    .... Based on the in vitro performance of indigenous Trichoderma spp. and Pseudomonas spp., four effective antagonists were selected and screened under greenhouse experiment for their growth enhancement potential...

  18. Proteomic Detection of Non-Annotated Protein-Coding Genes in Pseudomonas fluorescens Pf0-1

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Wook; Silby, Mark W.; Purvine, Samuel O.; Nicoll, Julie S.; Hixson, Kim K.; Monroe, Matthew E.; Nicora, Carrie D.; Lipton, Mary S.; Levy, Stuart B.

    2009-12-24

    Genome sequences are annotated by computational prediction of coding sequences, followed by similarity searches such as BLAST, which provide a layer of (possible) functional information. While the existence of processes such as alternative splicing complicates matters for eukaryote genomes, the view of bacterial genomes as a linear series of closely spaced genes leads to the assumption that computational annotations which predict such arrangements completely describe the coding capacity of bacterial genomes. We undertook a proteomic study to identify proteins expressed by Pseudomonas fluorescens Pf0-1 from genes which were not predicted during the genome annotation. Mapping peptides to the Pf0-1 genome sequence identified sixteen non-annotated protein-coding regions, of which nine were antisense to predicted genes, six were intergenic, and one read in the same direction as an annotated gene but in a different frame. The expression of all but one of the newly discovered genes was verified by RT-PCR. Few clues as to the function of the new genes were gleaned from informatic analyses, but potential orthologues in other Pseudomonas genomes were identified for eight of the new genes. The 16 newly identified genes improve the quality of the Pf0-1 genome annotation, and the detection of antisense protein-coding genes indicates the under-appreciated complexity of bacterial genome organization.

  19. Genetic responses induced in olive roots upon colonization by the biocontrol endophytic bacterium Pseudomonas fluorescens PICF7.

    Directory of Open Access Journals (Sweden)

    Elisabetta Schilirò

    Full Text Available Knowledge on the genetic basis underlying interactions between beneficial bacteria and woody plants is still very limited, and totally absent in the case of olive. We aimed to elucidate genetic responses taking place during the colonization of olive roots by the native endophyte Pseudomonas fluorescens PICF7, an effective biocontrol agent against Verticillium wilt of olive. Roots of olive plants grown under non-gnotobiotic conditions were collected at different time points after PICF7 inoculation. A Suppression Subtractive Hybridization cDNA library enriched in induced genes was generated. Quantitative real time PCR (qRT-PCR analysis validated the induction of selected olive genes. Computational analysis of 445 olive ESTs showed that plant defence and response to different stresses represented nearly 45% of genes induced in PICF7-colonized olive roots. Moreover, quantitative real-time PCR (qRT-PCR analysis confirmed induction of lipoxygenase, phenylpropanoid, terpenoids and plant hormones biosynthesis transcripts. Different classes of transcription factors (i.e., bHLH, WRKYs, GRAS1 were also induced. This work highlights for the first time the ability of an endophytic Pseudomonas spp. strain to mount a wide array of defence responses in an economically-relevant woody crop such as olive, helping to explain its biocontrol activity.

  20. Genetic Responses Induced in Olive Roots upon Colonization by the Biocontrol Endophytic Bacterium Pseudomonas fluorescens PICF7

    Science.gov (United States)

    Schilirò, Elisabetta; Ferrara, Massimo; Nigro, Franco; Mercado-Blanco, Jesús

    2012-01-01

    Knowledge on the genetic basis underlying interactions between beneficial bacteria and woody plants is still very limited, and totally absent in the case of olive. We aimed to elucidate genetic responses taking place during the colonization of olive roots by the native endophyte Pseudomonas fluorescens PICF7, an effective biocontrol agent against Verticillium wilt of olive. Roots of olive plants grown under non-gnotobiotic conditions were collected at different time points after PICF7 inoculation. A Suppression Subtractive Hybridization cDNA library enriched in induced genes was generated. Quantitative real time PCR (qRT-PCR) analysis validated the induction of selected olive genes. Computational analysis of 445 olive ESTs showed that plant defence and response to different stresses represented nearly 45% of genes induced in PICF7-colonized olive roots. Moreover, quantitative real-time PCR (qRT-PCR) analysis confirmed induction of lipoxygenase, phenylpropanoid, terpenoids and plant hormones biosynthesis transcripts. Different classes of transcription factors (i.e., bHLH, WRKYs, GRAS1) were also induced. This work highlights for the first time the ability of an endophytic Pseudomonas spp. strain to mount a wide array of defence responses in an economically-relevant woody crop such as olive, helping to explain its biocontrol activity. PMID:23144916

  1. Di-Adenosine Tetraphosphate (Ap4A) Metabolism Impacts Biofilm Formation by Pseudomonas fluorescens via Modulation of c-di-GMP-Dependent Pathways▿

    OpenAIRE

    Monds, Russell D.; Newell, Peter D.; Wagner, Jeffrey C.; Schwartzman, Julia A.; Lu, Wenyun; Rabinowitz, Joshua D.; O'Toole, George A.

    2010-01-01

    Dinucleoside tetraphosphates are common constituents of the cell and are thought to play diverse biological roles in organisms ranging from bacteria to humans. In this study we characterized two independent mechanisms by which di-adenosine tetraphosphate (Ap4A) metabolism impacts biofilm formation by Pseudomonas fluorescens. Null mutations in apaH, the gene encoding nucleoside tetraphosphate hydrolase, resulted in a marked increase in the cellular level of Ap4A. Concomitant with this increase...

  2. Biosynthesis of the antimicrobial cyclic lipopeptides nunamycin and nunapeptin by Pseudomonas fluorescens strain In5 is regulated by the LuxR-type transcriptional regulator NunF

    DEFF Research Database (Denmark)

    Hennessy, Rosanna Catherine; Phippen, Christopher; Nielsen, Kristian Fog

    2017-01-01

    Nunamycin and nunapeptin are two antimicrobial cyclic lipopeptides (CLPs) produced by Pseudomonas fluorescens In5 and synthesized by nonribosomal synthetases (NRPS) located on two gene clusters designated the nun-nup regulon. Organization of the regulon is similar to clusters found in other CLP-p...... that environmental elicitors may also influence nunF expression which upon activation regulates nunamycin and nunapeptin production required for the growth inhibition of phytopathogens....

  3. Stabilitäten der Benzaldehydlyase aus Pseudomonas fluorescens und der Carbonylreduktase aus Candida parapsilosis in wässrig-organischen Zweiphasensystemen

    OpenAIRE

    Van Den Wittenboer, Anne

    2009-01-01

    Benzaldehyde lyase from Pseudomonas fluorescens (BAL) and carbonylreductase from Candida parapsilosis (CPCR) are versatile catalysts for the production of various chiral intermediates, which are of interest for the pharmaceutical industry. Due to the mostly hydrophobic reactants only low productivities can be achieved in aqueous reaction systems and thus the use of alternative reaction media is desirable. Especially the use of aqueous-organic biphasic systems is promising, since the extractio...

  4. A modular esterase from Pseudomonas fluorescens subsp. cellulosa contains a non-catalytic cellulose-binding domain.

    Science.gov (United States)

    Ferreira, L M; Wood, T M; Williamson, G; Faulds, C; Hazlewood, G P; Black, G W; Gilbert, H J

    1993-09-01

    The 5' regions of genes xynB and xynC, coding for a xylanase and arabinofuranosidase respectively, are identical and are reiterated four times within the Pseudomonas fluorescens subsp. cellulosa genome. To isolate further copies of the reiterated xynB/C 5' region, a genomic library of Ps. fluorescens subsp. cellulosa DNA was screened with a probe constructed from the conserved region of xynB. DNA from one phage which hybridized to the probe, but not to sequences upstream or downstream of the reiterated xynB/C locus, was subcloned into pMTL22p to construct pFG1. The recombinant plasmid expressed a protein in Escherichia coli, designated esterase XYLD, of M(r) 58,500 which bound to cellulose but not to xylan. XYLD hydrolysed aryl esters, released acetate groups from acetylxylan and liberated 4-hydroxy-3-methoxycinnamic acid from destarched wheat bran. The nucleotide sequence of the XYLD-encoding gene, xynD, revealed an open reading frame of 1752 bp which directed the synthesis of a protein of M(r) 60,589. The 5' 817 bp of xynD and the amino acid sequence between residues 37 and 311 of XYLD were almost identical with the corresponding regions of xynB and xynC and their encoded proteins XYLB and XYLC. Truncated derivatives of XYLD lacking the N-terminal conserved sequence retained the capacity to hydrolyse ester linkages, but did not bind cellulose. Expression of truncated derivatives of xynD, comprising the 5' 817 bp sequence, encoded a non-catalytic polypeptide that bound cellulose. These data indicate that XYLD has a modular structure comprising of a N-terminal cellulose-binding domain and a C-terminal catalytic domain.

  5. Biological control of wheat root diseases by the CLP-producing strain Pseudomonas fluorescens HC1-07.

    Science.gov (United States)

    Yang, Ming-Ming; Wen, Shan-Shan; Mavrodi, Dmitri V; Mavrodi, Olga V; von Wettstein, Diter; Thomashow, Linda S; Guo, Jian-Hua; Weller, David M

    2014-03-01

    Pseudomonas fluorescens HC1-07, previously isolated from the phyllosphere of wheat grown in Hebei province, China, suppresses the soilborne disease of wheat take-all, caused by Gaeumannomyces graminis var. tritici. We report here that strain HC1-07 also suppresses Rhizoctonia root rot of wheat caused by Rhizoctonia solani AG-8. Strain HC1-07 produced a cyclic lipopeptide (CLP) with a molecular weight of 1,126.42 based on analysis by electrospray ionization mass spectrometry. Extracted CLP inhibited the growth of G. graminis var. tritici and R. solani in vitro. To determine the role of this CLP in biological control, plasposon mutagenesis was used to generate two nonproducing mutants, HC1-07viscB and HC1-07prtR2. Analysis of regions flanking plasposon insertions in HC1-07prtR2 and HC1-07viscB revealed that the inactivated genes were similar to prtR and viscB, respectively, of the well-described biocontrol strain P. fluorescens SBW25 that produces the CLP viscosin. Both genes in HC1-07 were required for the production of the viscosin-like CLP. The two mutants were less inhibitory to G. graminis var. tritici and R. solani in vitro and reduced in ability to suppress take-all. HC1-07viscB but not HC-07prtR2 was reduced in ability to suppress Rhizoctonia root rot. In addition to CLP production, prtR also played a role in protease production.

  6. Interaction between Medicago truncatula and Pseudomonas fluorescens: evaluation of costs and benefits across an elevated atmospheric CO(2.

    Directory of Open Access Journals (Sweden)

    Clémentine Lepinay

    Full Text Available Soil microorganisms play a key role in both plants nutrition and health. Their relation with plant varies from mutualism to parasitism, according to the balance of costs and benefits for the two partners of the interaction. These interactions involved the liberation of plant organic compounds via rhizodeposition. Modification of atmospheric CO(2 concentration may affect rhizodeposition and as a consequence trophic interactions that bind plants and microorganisms. Positive effect of elevated CO(2 on plants are rather well known but consequences for micoorganisms and their interactions with plants are still poorly understood. A gnotobiotic system has been developed to study the interaction between Medicago truncatula Jemalong J5 and the mutualistic bacteria Pseudomonas fluorescens strain C7R12 under two atmospheric CO(2 concentrations: ambient (365 ppm versus enriched (750 ppm. Costs and benefits for each partner have been determined over time by measuring plant development and growth, the C and N contents of the various plant parts and the density of the bacteria in rhizosphere compartments. Following the increase in CO(2, there was a beneficial effect of P. fluorescens C7R12 on development, vegetative growth, and C/N content of M. truncatula. Concerning plant reproduction, an early seed production was noticed in presence of the bacterial strain combined with increased atmospheric CO(2 conditions. Paradoxically, this transient increase in seed production was correlated with a decrease in bacterial density in the rhizosphere soil, revealing a cost of increased CO(2 for the bacterial strain. This shift of costs-benefits ratio disappeared later during the plant growth. In conclusion, the increase in CO(2 concentration modifies transiently the cost-benefit balance in favor of the plant. These results may be explained either by a competition between the two partners or a change in bacterial physiology. The ecosystem functioning depends on the

  7. PENGARUH APLIKASI PSEUDOMONAS FLUORESCENS P60 TERHADAP MUTU PATOLOGIS, MUTU FISIOLOGIS, DAN PERTUMBUHAN BIBIT PADI IR 64

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    Lisa Navitasari

    2014-08-01

    Full Text Available Effect of Pseudomonas fluorescens P60 on pathological and physiological quality and growth of rice IR 64  seedlings. The research objectives were (1 detection and identification of seed-borne pathogens of IR 64 rice, (2 testing Pseudomonas fluorescents P60 in inhibiting the in vitro growth of seed-borne pathogens colonies, (3 testing P. fluorescents P60 for pathological and physiological seed quality, and (4 testing P. fluorescents P60 on the growth of seedlings in the greenhouse. The results showed that some seed-borne pathogens can be found both on farmers’ IR 64 rice and factory’s; they were Aspergillus flavus, Alternaria padwickii, Pseudomonas glumae, and P. syringae. Application of P. flourescens P60 was able to inhibit the in vitrogrowth of colonies of all seed-borne pathogens, except P. syringae.  Related to pathological quality, the effect of P. flourescens P60 on percentage of seed-borne pathogens attack did not significantly different from that of benomil but smaller than distilled water. On the physiological quality of seeds, treatment of P. flourescens P60 has the same effect with benomil and distilled water, with  germination rate was more than 80%. In the greenhouse study,treatment of seed immersion time  in P. flourescens P60 suspension showed that the effect of immersion time as long as15 minutes and 25 minutes on  seedling height, root length, and seedling dry weightdid not significantly different. were. However, 25 minutes immersion time resulted in fresh seedling weight and root dry weight higher than that of 15 minutes immersion time.

  8. Functional Characterization of the Mannitol Promoter of Pseudomonas fluorescens DSM 50106 and Its Application for a Mannitol-Inducible Expression System for Pseudomonas putida KT2440.

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    Jana Hoffmann

    Full Text Available A new pBBR1MCS-2-derived vector containing the Pseudomonas fluorescens DSM10506 mannitol promoter PmtlE and mtlR encoding its AraC/XylS type transcriptional activator was constructed and optimized for low basal expression. Mannitol, arabitol, and glucitol-inducible gene expression was demonstrated with Pseudomonas putida and eGFP as reporter gene. The new vector was applied for functional characterization of PmtlE. Identification of the DNA binding site of MtlR was achieved by in vivo eGFP measurement with PmtlE wild type and mutants thereof. Moreover, purified MtlR was applied for detailed in vitro investigations using electrophoretic mobility shift assays and DNaseI footprinting experiments. The obtained data suggest that MtlR binds to PmtlE as a dimer. The proposed DNA binding site of MtlR is AGTGC-N5-AGTAT-N7-AGTGC-N5-AGGAT. The transcription activation mechanism includes two binding sites with different binding affinities, a strong upstream binding site and a weaker downstream binding site. The presence of the weak downstream binding site was shown to be necessary to sustain mannitol-inducibility of PmtlE. Two possible functions of mannitol are discussed; the effector might stabilize binding of the second monomer to the downstream half site or promote transcription activation by inducing a conformational change of the regulator that influences the contact to the RNA polymerase.

  9. Functional Characterization of the Mannitol Promoter of Pseudomonas fluorescens DSM 50106 and Its Application for a Mannitol-Inducible Expression System for Pseudomonas putida KT2440

    Science.gov (United States)

    Hoffmann, Jana; Altenbuchner, Josef

    2015-01-01

    A new pBBR1MCS-2-derived vector containing the Pseudomonas fluorescens DSM10506 mannitol promoter PmtlE and mtlR encoding its AraC/XylS type transcriptional activator was constructed and optimized for low basal expression. Mannitol, arabitol, and glucitol-inducible gene expression was demonstrated with Pseudomonas putida and eGFP as reporter gene. The new vector was applied for functional characterization of PmtlE. Identification of the DNA binding site of MtlR was achieved by in vivo eGFP measurement with PmtlE wild type and mutants thereof. Moreover, purified MtlR was applied for detailed in vitro investigations using electrophoretic mobility shift assays and DNaseI footprinting experiments. The obtained data suggest that MtlR binds to PmtlE as a dimer. The proposed DNA binding site of MtlR is AGTGC-N5-AGTAT-N7-AGTGC-N5-AGGAT. The transcription activation mechanism includes two binding sites with different binding affinities, a strong upstream binding site and a weaker downstream binding site. The presence of the weak downstream binding site was shown to be necessary to sustain mannitol-inducibility of PmtlE. Two possible functions of mannitol are discussed; the effector might stabilize binding of the second monomer to the downstream half site or promote transcription activation by inducing a conformational change of the regulator that influences the contact to the RNA polymerase. PMID:26207762

  10. In vitro effects of Laccaria bicolor S238 N and Pseudomonas fluorescens strain BBc6 on rooting of de-rooted shoot hypocotyls of Norway spruce.

    Science.gov (United States)

    Karabaghli, C.; Frey-Klett, P.; Sotta, B.; Bonnet, M.; Le Tacon, F.

    1998-02-01

    The ectomycorrhizal fungus Laccaria bicolor S238 N and the bacterium Pseudomonas fluorescens BBc6 were used separately and in combination to induce in vitro rooting of de-rooted shoot hypocotyls of Norway spruce (Picea abies (L.) Karst.). When the culture medium was supplemented with tryptophan, a precursor of indole-3-acetic acid (IAA) synthesis, the presence of the ectomycorrhizal fungus increased the percentage of hypocotyls forming roots; furthermore, both the fungal and bacterial inoculations enhanced the number of roots formed per rooted hypocotyl. Similar results were obtained by adding exogenous IAA (5 and 10 &mgr;M) to the rooting medium. After the rooting phase, the fungal inoculation enhanced adventitious root elongation and branching as well as the aerial growth of the cuttings. Pseudomonas fluorescens BBc6 had no effect on these parameters. The production of IAA by pure cultures of L. bicolor S238 N and P. fluorescens BBc6 was estimated by immunochemical analysis using specific anti-IAA antibodies. Both L. bicolor S238 N and P. fluorescens BBc6 synthesized IAA in pure culture and synthesis was stimulated in the presence of tryptophan. Thus, the effect of the fungus in stimulating adventitious root formation and subsequent elongation and branching can be attributed, at least partially, to the synthesis of IAA by the fungus. The finding that P. fluorescens BBc6 had no effect on root elongation and branching although it produced IAA suggests that either IAA was not the only parameter involved in the stimulation of these processes by L. bicolor S238 N or the bacterium produced other compounds that counteracted the stimulatory effects of IAA on root elongation and branching.

  11. The Effect of Bacteria Colony Pseudomonas fluorescens (UB_Pf1 and Bacillus subtilis (UB_Bs1 on the Mortality of Pratylenchus coffeae (Tylenchida: Pratylenchidae

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    Presti Mardiyani Purwaningtyas

    2016-11-01

    Full Text Available Parasitic Root-Lession nematode of Pratylenchus coffeae can reduce the Indonesian coffee plants productivity. Several studies reported that Pseudomonas fluorescens and Bacillus subtilis endophytic bacteria were antagonistic bacteria to nematode. The objective of this research was to reveal the effectiveness of bacterial colonies density of P. fluorescens (UB_Pf1, B.subtilis (UB BS1, and a combination of both bacteria on nematode mortality using median lethal concentration (LC50 and median lethal time 50 (LT50. The densities of bacteria used in this study were 107, 109, 1011 and 1013 cfu/ml. 35 testing nematodes were used and the mortality was counted at 6, 12, 24, 36, and 48 hours after treatments. The results showed that LC50 values of P. fluorescens was (UB_Pf1 was 4,3x108 cfu/ml, LC50 B. subtilis (UB_Bs1 was 1,9x109cfu/ ml, and LC50 combination of both bacteria was, 8x107 cfu/ml. It implies that the application of the combination of both bacteria are more pathogenic than single bacterial treatment. The results also showed that the highest LT50 value was 13.21  hours combination of bacterial colonies with a density of 1013 cfu/ml and the lowest LT50 value was 52.00 hours on P. fluorescens (UB_Pf1 treatment with colonies density of 107 cfu/ml.How to CitePurwaningtyas, P. M., Rahardjo, B. T., & Tarno, H. (2016. The Effect of Bacteria Colony Pseudomonas fluorescens (UB_Pf1 and Bacillus subtilis (UB_Bs1 on the Mortality of Pratylenchus coffeae (Tylenchida: Pratylenchidae. Biosaintifika: Journal of Biology & Biology Education, 8(3, 286-293. 

  12. Interaction of the psychrotroph Pseudomonas fluorescens In5 with phytopathogens in cold soils

    DEFF Research Database (Denmark)

    Hennessy, Rosanna Catherine; Olsson, Stefan; Stougaard, Peter

    sequencing was conducted to investigate the response of the bacterium to different plant pathogens in dual-culture. Results/Discussion: Key biocontrol components of P. fluorescens In5 identified to date include the two secondary metabolites nunamycin and nunapeptin that form part of a complex interaction...... for combatting plant pathogenic fungi. Current studies are aimed at unravelling further the complex mode of action underpinning the antagonistic activity of In5 in order to develop effective microbial biocontrol agents (mBCAs) for the management of soil-borne plant diseases.......Aim: Potato cultivation in southwest Greenland, at Inneruulalik, omits the use of pesticides while relying on limited crop rotations and despite the presence of plant pathogens in the soil does not suffer from major disease outbreaks. Previously, we have shown that the soil at Inneruulalik...

  13. Effect of biocontrol agent Pseudomonas fluorescens 2P24 on soil fungal community in cucumber rhizosphere using T-RFLP and DGGE.

    Science.gov (United States)

    Gao, Guanpeng; Yin, Danhan; Chen, Shengju; Xia, Fei; Yang, Jie; Li, Qing; Wang, Wei

    2012-01-01

    Fungi and fungal community play important roles in the soil ecosystem, and the diversity of fungal community could act as natural antagonists of various plant pathogens. Biological control is a promising method to protect plants as chemical pesticides may cause environment pollution. Pseudomonas fluorescens 2P24 had strong inhibitory on Rastonia solanacearum, Fusarium oxysporum and Rhizoctonia solani, etc., and was isolated from the wheat rhizosphere take-all decline soils in Shandong province, China. However, its potential effect on soil fungal community was still unknown. In this study, the gfp-labeled P. fluorescens 2P24 was inoculated into cucumber rhizosphere, and the survival of 2P24 was monitored weekly. The amount decreased from 10(8) to 10(5) CFU/g dry soils. The effect of 2P24 on soil fungal community in cucumber rhizosphere was investigated using T-RFLP and DGGE. In T-RFLP analysis, principle component analysis showed that the soil fungal community was greatly influenced at first, digested with restriction enzyme Hinf I and Taq I. However, there was little difference as digested by different enzymes. DGGE results demonstrated that the soil fungal community was greatly shocked at the beginning, but it recovered slowly with the decline of P. fluorescens 2P24. Four weeks later, there was little difference between the treatment and control. Generally speaking, the effect of P. fluorescens 2P24 on soil fungal community in cucumber rhizosphere was just transient.

  14. Effect of biocontrol agent Pseudomonas fluorescens 2P24 on soil fungal community in cucumber rhizosphere using T-RFLP and DGGE.

    Directory of Open Access Journals (Sweden)

    Guanpeng Gao

    Full Text Available Fungi and fungal community play important roles in the soil ecosystem, and the diversity of fungal community could act as natural antagonists of various plant pathogens. Biological control is a promising method to protect plants as chemical pesticides may cause environment pollution. Pseudomonas fluorescens 2P24 had strong inhibitory on Rastonia solanacearum, Fusarium oxysporum and Rhizoctonia solani, etc., and was isolated from the wheat rhizosphere take-all decline soils in Shandong province, China. However, its potential effect on soil fungal community was still unknown. In this study, the gfp-labeled P. fluorescens 2P24 was inoculated into cucumber rhizosphere, and the survival of 2P24 was monitored weekly. The amount decreased from 10(8 to 10(5 CFU/g dry soils. The effect of 2P24 on soil fungal community in cucumber rhizosphere was investigated using T-RFLP and DGGE. In T-RFLP analysis, principle component analysis showed that the soil fungal community was greatly influenced at first, digested with restriction enzyme Hinf I and Taq I. However, there was little difference as digested by different enzymes. DGGE results demonstrated that the soil fungal community was greatly shocked at the beginning, but it recovered slowly with the decline of P. fluorescens 2P24. Four weeks later, there was little difference between the treatment and control. Generally speaking, the effect of P. fluorescens 2P24 on soil fungal community in cucumber rhizosphere was just transient.

  15. Effect of Two Biological Formulations Based on Bacillus subtilis and Pseudomonas fluorescens on Control of Didymella applanata, the Causal Agent of Red Raspberry Cane Spur Blight

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    Margarita Shternshis

    2016-01-01

    Full Text Available In vitro and in vivo studies were conducted to estimate the efficacy of the two microbial formulations based on Bacillus subtilis Cohn. and Pseudomonas fluorescens Mig. on the fungus Didymella applanata (Niessl. Sacc., the causal agent of red raspberry (Rubus idaeus L. spur blight. In vitro, both bacteria reduced the growth of D. applanata. In inoculation experiments with raspberry canes in two cultivars with different susceptibility to D. applanata, these antagonistic bacteria suppressed fungal development by reducing the lesions area and the number of D. applanata fruiting bodies. Field trials of two biological formulations under natural conditions showed a significant suppression of the disease. B. subtilis and P. fluorescens included in the formulations revealed antagonistic activity towards D. applanata that depended on the red raspberry cultivar and weather conditions. In all cases, B. subtilis showed better results than P. fluorescens in biocontrol of the raspberry spur blight. This study demonstrated for the first time the ability of the biocontrol agents B. subtilis and P. fluorescens to suppress red raspberry cane spur blight, a serious worldwide disease.

  16. Virulence of the Pseudomonas fluorescens clinical strain MFN1032 towards Dictyostelium discoideum and macrophages in relation with type III secretion system

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    Sperandio Daniel

    2012-09-01

    Full Text Available Abstract Background Pseudomonas fluorescens biovar I MFN1032 is a clinical isolate able to grow at 37°C. This strain displays secretion-mediated hemolytic activity involving phospholipase C and cyclolipopeptides, and a cell-associated hemolytic activity distinct from the secreted hemolytic activity. Cell-associated hemolysis is independent of biosurfactant production and remains in a gacA mutant. Disruption of the hrpU-like operon (the basal part of type III secretion system from rhizospheric strains suppresses this activity. We hypothesized that this phenotype could reflect evolution of an ancestral mechanism involved in the survival of this species in its natural niche. In this study, we evaluated the hrpU-like operon’s contribution to other virulence mechanisms using a panel of Pseudomonas strains from various sources. Results We found that MFN1032 inhibited the growth of the amoebae Dictyostelium discoideum and that this inhibition involved the hrpU-like operon and was absent in a gacA mutant. MFN1032 was capable of causing macrophage lysis, if the hrpU-like operon was intact, and this cytotoxicity remained in a gacA mutant. Cell-associated hemolytic activity and macrophage necrosis were found in other P. fluorescens clinical isolates, but not in biocontrol P. fluorescens strains harbouring hrpU-like operon. The growth of Dictyostelium discoideum was inhibited to a different extent by P. fluorescens strains without correlation between this inhibition and hrpU-like operon sequences. Conclusions In P. fluorescens MFN1032, the basal part of type III secretion system plays a role in D. discoideum growth inhibition and macrophage necrosis. The inhibition of D. discoideum growth is dependent on the GacS/GacA system, while cell-associated hemolytic activity and macrophage lysis are not. Virulence against eukaryotic cells based on the hrpU-like operon may be more than just a stochastic evolution of a conserved system dedicated to survival in

  17. Ability of the marine bacterium Pseudomonas fluorescens BA3SM1 to counteract the toxicity of CdSe nanoparticles.

    Science.gov (United States)

    Poirier, Isabelle; Kuhn, Lauriane; Demortière, Arnaud; Mirvaux, Boris; Hammann, Philippe; Chicher, Johana; Caplat, Christelle; Pallud, Marie; Bertrand, Martine

    2016-10-04

    In the marine environment, bacteria from estuarine and coastal sediments are among the first targets of nanoparticle pollution; it is therefore relevant to improve the knowledge of interactions between bacteria and nanoparticles. In this work, the response of the marine bacterium Pseudomonas fluorescens BA3SM1 to CdSe nanocrystals (CdSe NPs) of 3nm (NP3) and 8nm (NP8) in diameter was evaluated through microscopic, physiological, biochemical and proteomic approaches. Transmission electron microscopy images showed that NP3 were able to penetrate the bacteria, while NP8 were highly concentrated around the cells, embedded in large exopolysaccharides. In our experimental conditions, both CdSe NP sizes induced a decrease in respiration during the stationary growth phase, while only NP8 caused growth retardation and a decrease in pyoverdine production. Proteomic analyses highlighted that the strain responded to CdSe NP toxicity by inducing various defence mechanisms such as cell aggregation, extracellular CdSe NP sequestration, effective protection against oxidative stress, modifications of envelope organization and properties, and cadmium export. In addition, BA3SM1 presented a biosorption capacity of 1.6×10(16)NP3/g dry weight and 1.7×10(15)NP8/g dry weight. This strain therefore appears as a promising agent for NP bioremediation processes. Proteomic data are available via ProteomeXchange with identifier PXD004012. To the best of our knowledge, this is the first report focussing on the effects of CdSe colloidal nanocrystals (CdSe NPs) on a marine strain of Pseudomonas fluorescens. CdSe NPs are extensively used in the industry of renewable energies and it is regrettably expected that these pollutants will sometime soon appear in the marine environment through surface runoff, urban effluents and rivers. Bacteria living in estuarine and coastal sediments will be among the first targets of these new pollutants. The pseudomonads are frequently found in these ecosystems

  18. Metabolic and Transcriptomic Changes Induced in Arabidopsis by the Rhizobacterium Pseudomonas fluorescens SS1011[W][OA

    Science.gov (United States)

    van de Mortel, Judith E.; de Vos, Ric C.H.; Dekkers, Ester; Pineda, Ana; Guillod, Leandre; Bouwmeester, Klaas; van Loon, Joop J.A.; Dicke, Marcel; Raaijmakers, Jos M.

    2012-01-01

    Systemic resistance induced in plants by nonpathogenic rhizobacteria is typically effective against multiple pathogens. Here, we show that root-colonizing Pseudomonas fluorescens strain SS101 (Pf.SS101) enhanced resistance in Arabidopsis (Arabidopsis thaliana) against several bacterial pathogens, including Pseudomonas syringae pv tomato (Pst) and the insect pest Spodoptera exigua. Transcriptomic analysis and bioassays with specific Arabidopsis mutants revealed that, unlike many other rhizobacteria, the Pf.SS101-induced resistance response to Pst is dependent on salicylic acid signaling and not on jasmonic acid and ethylene signaling. Genome-wide transcriptomic and untargeted metabolomic analyses showed that in roots and leaves of Arabidopsis plants treated with Pf.SS101, approximately 1,910 genes and 50 metabolites were differentially regulated relative to untreated plants. Integration of both sets of “omics” data pointed to a prominent role of camalexin and glucosinolates in the Pf.SS101-induced resistance response. Subsequent bioassays with seven Arabidopsis mutants (myb51, cyp79B2cyp79B3, cyp81F2, pen2, cyp71A12, cyp71A13, and myb28myb29) disrupted in the biosynthesis pathways for these plant secondary metabolites showed that camalexin and glucosinolates are indeed required for the induction of Pst resistance by Pf.SS101. Also for the insect S. exigua, the indolic glucosinolates appeared to play a role in the Pf.SS101-induced resistance response. This study provides, to our knowledge for the first time, insight into the substantial biochemical and temporal transcriptional changes in Arabidopsis associated with the salicylic acid-dependent resistance response induced by specific rhizobacteria. PMID:23073694

  19. Phenazine-1-Carboxylic Acid Production by Pseudomonas fluorescens LBUM636 Alters Phytophthora infestans Growth and Late Blight Development.

    Science.gov (United States)

    Morrison, Christopher K; Arseneault, Tanya; Novinscak, Amy; Filion, Martin

    2017-03-01

    Phytophthora infestans causes late blight of potato, one of the most devastating diseases affecting potato production. Alternative approaches for controlling late blight are being increasingly sought due to increasing environmental concerns over the use of chemical pesticides and the increasing resistance of P. infestans to fungicides. Our research group has isolated a new strain of Pseudomonas fluorescens (LBUM636) of biocontrol interest producing the antibiotic phenazine-1-carboxylic acid (PCA). Wild-type LBUM636 was shown to significantly inhibit the growth of Phytophthora infestans in in vitro confrontational assays whereas its isogenic mutant (phzC-; not producing PCA) only slightly altered the pathogen's growth. Wild-type LBUM636 but not the phzC- mutant also completely repressed disease symptom development on tubers. A pot experiment revealed that wild-type LBUM636 can significantly reduce P. infestans populations in the rhizosphere and in the roots of potato plants, as well as reduce in planta disease symptoms due to PCA production. The expression of eight common plant defense-related genes (ChtA, PR-1b, PR-2, PR-5, LOX, PIN2, PAL-2, and ERF3) was quantified in tubers, roots, and leaves by reverse-transcription quantitative polymerase chain reaction and revealed that the biocontrol observed was not associated with the induction of a plant defense response by LBUM636. Instead, a direct interaction between P. infestans and LBUM636 is required and PCA production appears to be a key factor for LBUM636's biocontrol ability.

  20. A novel psychrophilic lipase from Pseudomonas fluorescens with unique property in chiral resolution and biodiesel production via transesterification.

    Science.gov (United States)

    Luo, Yu; Zheng, Yitao; Jiang, Zhengbing; Ma, Yushu; Wei, Dongzhi

    2006-11-01

    A lipase-producing bacterium strain B68 screened from soil samples of China was identified as Pseudomonas fluorescens. With GenomeWalker, the open reading frame of lipase gene lipB68, encoding 476 amino acids, was cloned and expressed in Escherichia coli BL21 (DE3). By affinity chromatography, the recombinant LipB68 protein was purified to the purity of 95%. As a member of lipase subfamily I.3, LipB68 has a unique optimum temperature of 20 degrees C, which was the lowest in this subfamily. In chiral resolution, LipB68 effectively catalyzed the transesterification of both alpha-phenylethanol and alpha-phenylpropanol at 20 degrees C, achieving E values greater than 100 and 60 after 120 h, respectively. Among all the known catalysts in biodiesel production, LipB68 produced biodiesel with a yield of 92% after 12 h, at the lowest temperature of 20 degrees C, and is the first one of the I.3 lipase subfamily reported to be capable of catalyzing the transesterification reaction of biodiesel production. Since lipase-mediated biodiesel production is normally carried out at 35-50 degrees C, the availability of a highly active lipase with a low optimal temperature can provide substantial savings in energy consumption. Thus, this novel psychrophilic lipase (LipB68) may represent a highly competitive energy-saving biocatalyst.

  1. A novel psychrophilic lipase from Pseudomonas fluorescens with unique property in chiral resolution and biodiesel production via transesterification

    Energy Technology Data Exchange (ETDEWEB)

    Luo Yu; Zheng Yitao; Jiang Zhengbing; Ma Yushu; Wei Dongzhi [East China Univ. of Science and Tech., Shanghai (China). State Key Lab. of Bioreactor Engineering

    2006-11-15

    A lipase-producing bacterium strain B68 screened from soil samples of China was identified as Pseudomonas fluorescens. With GenomeWalker, the open reading frame of lipase gene lipB68, encoding 476 amino acids, was cloned and expressed in Escherichia coli BL21 (DE3). By affinity chromatography, the recombinant LipB68 protein was purified to the purity of 95%. As a member of lipase subfamily I.3, LipB68 has a unique optimum temperature of 20 C, which was the lowest in this subfamily. In chiral resolution, LipB68 effectively catalyzed the transesterification of both a-phenylethanol and a-phenylpropanol at 20 C, achieving E values greater than 100 and 60 after 120 h, respectively. Among all the known catalysts in biodiesel production, LipB68 produced biodiesel with a yield of 92% after 12 h, at the lowest temperature of 20 C, and is the first one of the I.3 lipase subfamily reported to be capable of catalyzing the transesterification reaction of biodiesel production. Since lipasemediated biodiesel production is normally carried out at 35-50 C, the availability of a highly active lipase with a low optimal temperature can provide substantial savings in energy consumption. Thus, this novel psychrophilic lipase (LipB68) may represent a highly competitive energy-saving biocatalyst. (orig.)

  2. A ptsP deficiency in PGPR Pseudomonas fluorescens SF39a affects bacteriocin production and bacterial fitness in the wheat rhizosphere.

    Science.gov (United States)

    Godino, Agustina; Príncipe, Analía; Fischer, Sonia

    2016-04-01

    Pseudomonas fluorescens SF39a is a plant-growth-promoting bacterium isolated from wheat rhizosphere. In this report, we demonstrate that this native strain secretes bacteriocins that inhibit growth of phytopathogenic strains of the genera Pseudomonas and Xanthomonas. An S-type pyocin gene was detected in the genome of strain SF39a and named pys. A non-polar pys::Km mutant was constructed. The bacteriocin production was impaired in this mutant. To identify genes involved in bacteriocin regulation, random transposon mutagenesis was carried out. A miniTn5Km1 mutant, called P. fluorescens SF39a-451, showed strongly reduced bacteriocin production. This phenotype was caused by inactivation of the ptsP gene which encodes a phosphoenolpyruvate phosphotransferase (EI(Ntr)) of the nitrogen-related phosphotransferase system (PTS(Ntr)). In addition, this mutant showed a decrease in biofilm formation and protease production, and an increase in surface motility and pyoverdine production compared with the wild-type strain. Moreover, we investigated the ability of strain SF39a-451 to colonize the wheat rhizosphere under greenhouse conditions. Interestingly, the mutant was less competitive than the wild-type strain in the rhizosphere. To our knowledge, this study provides the first evidence of both the relevance of the ptsP gene in bacteriocin production and functional characterization of a pyocin S in P. fluorescens. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  3. Draft genome sequences of seven 4-Formylaminooxyvinylglycine producers belonging to the Pseudomonas fluorescens species complex

    Science.gov (United States)

    Vinylglycines are non-proteinogenic amino acids that inhibit amino acid metabolism and ethylene production. In this report, we describe the draft genome sequences of seven isolates of Pseudomonas that produce 4-formylaminooxyvinylglycine, a compound known to inhibit the germination of grasses and t...

  4. Biosynthesis of the antimicrobial cyclic lipopeptides nunamycin and nunapeptin by Pseudomonas fluorescens strain In5 is regulated by the LuxR-type transcriptional regulator NunF

    DEFF Research Database (Denmark)

    Hennessy, Rosanna Catherine; Phippen, Christopher; Nielsen, Kristian Fog

    2017-01-01

    Nunamycin and nunapeptin are two antimicrobial cyclic lipopeptides (CLPs) produced by Pseudomonas fluorescens In5 and synthesized by nonribosomal synthetases (NRPS) located on two gene clusters designated the nun-nup regulon. Organization of the regulon is similar to clusters found in other CLP......-producing pseudomonads except for the border regions where putative LuxR-type regulators are located. This study focuses on understanding the regulatory role of the LuxR-type-encoding gene nunF in CLP production of P. fluorescens In5. Functional analysis of nunF coupled with liquid chromatography-high-resolution mass...... spectrometry (LC-HRMS) showed that CLP biosynthesis is regulated by nunF. Quantitative real-time PCR analysis indicated that transcription of the NRPS genes catalyzing CLP production is strongly reduced when nunF is mutated indicating that nunF is part of the nun-nup regulon. Swarming and biofilm formation...

  5. Biocidal Activity of Formaldehyde and Nonformaldehyde Biocides toward Mycobacterium immunogenum and Pseudomonas fluorescens in Pure and Mixed Suspensions in Synthetic Metalworking Fluid and Saline

    Science.gov (United States)

    Selvaraju, Suresh B.; Khan, Izhar U. H.; Yadav, Jagjit S.

    2005-01-01

    The microbicidal activity of four different biocides was studied in synthetic metalworking fluid (MWF) against Mycobacterium immunogenum, a suspected causative agent for hypersensitivity pneumonitis, and Pseudomonas fluorescens, a representative for the predominant gram-negative bacterial contaminants of MWF. The results indicated that M. immunogenum is more resistant than P. fluorescens to the tested formaldehyde-releasing biocides (Grotan and Bioban), isothiazolone (Kathon), and phenolic biocide (Preventol). Kathon was effective against mycobacteria at lower concentrations than the other three test biocides in MWF. In general, there was a marked increase in biocidal resistance of both the test organisms when present in MWF matrix compared to saline. Increased resistance of the two test organisms to biocides was observed when they were in a mixed suspension (1:1 ratio). The results indicate the protective effect of the MWF matrix against the action of commonly used biocides on the MWF-colonizing microbial species of occupational health significance, including mycobacteria. PMID:15640232

  6. Survival of Escherichia coli o157:h7 co-cultured with different levels of pseudomonas fluorescens and lactobacillus plantarum on fresh beef

    Science.gov (United States)

    Tshabalala, P. A.; de Kock, H. L.; Buys, E. M.

    2012-01-01

    The purpose of this study was to investigate the effect of different levels of Pseudomonas fluorescens (102 and 106 log10 cfu/ml) and Lactobacillus plantarum (102 and 104 log10 cfu/ml) on the growth of Escherichia coli O157:H7 on beef loins. Beef loins inoculated with E. coli O157:H7 and P. fluorescens were aerobically stored for 7 days at 4 ºC, while those inoculated with E. coli O157:H7 and L. plantarum were vacuum packaged and stored for 8 weeks at 4 ºC. Aerobic Plate Counts (APC), E. coli O157:H7 and either P. fluorescens or L. plantarum counts were determined at different storage intervals. For the aerobically packaged beef loins, E. coli O157:H7 was detected throughout the 7 day storage period regardless of the P. fluorescens level in the inoculum. For the vacuum packaged beef loins, similar inoculum levels of E. coli O157:H7 and L. plantarum allowed E. coli O157:H7 to survive until week 5 of storage, while a higher inoculum level of L. plantarum inhibited E. coli O157:H7 from week 3. Once fresh beef has been contaminated with E. coli O157:H7, the level of P. fluorescens in the background flora does not inhibit its survival and growth. However, under vacuum storage, the application of L. plantarum as a biopreservative inhibits the survival of E. coli O157:H7 on beef. The higher the level of L. plantarum in the system, the earlier the onset of the inhibition. Farmers and abattoirs have to strengthen preventive strategies to eliminate contamination of beef carcasses with E. coli O157:H7. PMID:24031970

  7. Reduction of Fusarium wilt in watermelon by Pseudomonas chlororaphis PCL1391 and P. fluorescens WCS365

    Directory of Open Access Journals (Sweden)

    G.T. Tziros

    2007-12-01

    Full Text Available Fusarium wilt of watermelon (Citrullus lanatus caused by Fusarium oxysporum f. sp. niveum is a devastatine soil-borne disease that causes extensive losses throughout the world. Two known Pseudomonas biocontrol strains were used separately and in combination to assess their antagonistic effectiveness against F. oxysporum f. sp. niveum in pot experiments. P. chlororaphis PCL1391 signifi cantly reduced disease severity. P. fl uorescens WCS365 was less effective in disease suppression, while a combination of the two bacteria had intermediate effects. The biological control of Fusarium wilt with P. chlororaphis offers a potentially useful tool in an integrated pest management program to control Fusarium wilt of watermelon.

  8. Investigation for zoonotic disease pathogens (Aeromonas hydrophila, Pseudomonas fluorescens, Streptococcus iniae) seen in carp farms in Duhok region of Northern Iraq by molecular methods

    Science.gov (United States)

    Mohammed, Kamiran Abdulrahman; Arabacı, Muhammed; Önalan, Şükrü

    2017-04-01

    The aim of this study was to determine the zoonotic bacteria in carp farms in Duhok region of the Northern Iraq. Carp is the main fish species cultured in the Duhok region. The most common zoonotic bacteria generally seen in carp farms are Aeromonas hydrophila, Pseudomonas fluorescens and Streptococcus iniae. Samples were collected from 20 carp farms in the Duhok Region of the Northern Iraq. Six carp samples were collected from each carp farm. Head kidney tissue samples and intestine tissue samples were collected from each carp sample. Than head kidney and intestine tissue samples were pooled. The total bacterial DNA extraction from the pooled each 20 head kidney tissue samples and pooled each 20 intestinal tissue samples. Primers for pathogens were originally designed from 16S Ribosomal gene region. Zoonotic bacteria were scanned in all tissue samples by absent / present analysis in the RT-PCR. After RT-PCR, Capillary gel electrophoresis bands were used for the confirmation of the size of amplicon which was planned during primer designing stage. As a result, one sample was positive in respect to Aeromonas hydrophila, from intestine and one carp farm was positive in respect to Pseudomonas fluorescens from intestine and two carp farms were positive in respect to Streptococcus iniae. Totally 17 of 20 carp farms were negative in respect to the zoonotic bacteria. In conclusion the zoonotic bacteria were very low (15 %) in carp farms from the Duhok Region in the Northern Iraq. Only in one Carp farms, both Aeromonas hydrophila and Pseudomonas fluorescens were positive. Also Streptococcus inia were positive in two carp farms.

  9. Toluene promotes lid 2 interfacial activation of cold active solvent tolerant lipase from Pseudomonas fluorescens strain AMS8.

    Science.gov (United States)

    Yaacob, Norhayati; Mohamad Ali, Mohd Shukuri; Salleh, Abu Bakar; Rahman, Raja Noor Zaliha Raja Abdul; Leow, Adam Thean Chor

    2016-07-01

    The utilization of cold active lipases in organic solvents proves an excellent approach for chiral synthesis and modification of fats and oil due to the inherent flexibility of lipases under low water conditions. In order to verify whether this lipase can function as a valuable synthetic catalyst, the mechanism concerning activation of the lid and interacting solvent residues in the presence of organic solvent must be well understood. A new alkaline cold-adapted lipase, AMS8, from Pseudomonas fluorescens was studied for its structural adaptation and flexibility prior to its exposure to non-polar, polar aprotic and protic solvents. Solvents such as ethanol, toluene, DMSO and 2-propanol showed to have good interactions with active sites. Asparagine (Asn) and tyrosine (Tyr) were key residues attracted to solvents because they could form hydrogen bonds. Unlike in other solvents, Phe-18, Tyr-236 and Tyr-318 were predicted to have aromatic-aromatic side-chain interactions with toluene. Non-polar solvent also was found to possess highest energy binding compared to polar solvents. Due to this circumstance, the interaction of toluene and AMS8 lipase was primarily based on hydrophobicity and molecular recognition. The molecular dynamic simulation showed that lid 2 (residues 148-167) was very flexible in toluene and Ca(2+). As a result, lid 2 moves away from the catalytic areas, leaving an opening for better substrate accessibility which promotes protein activation. Only a single lid (lid 2) showed the movement following interactions with toluene, although AMS8 lipase displayed double lids. The secondary conformation of AMS8 lipase that was affected by toluene observed a reduction of helical strands and increased coil structure. Overall, this work shows that cold active lipase, AMS8 exhibits distinguish interfacial activation and stability in the presence of polar and non-polar solvents. Copyright © 2016. Published by Elsevier Inc.

  10. Pseudomonas fluorescens F113 Mutant with Enhanced Competitive Colonization Ability and Improved Biocontrol Activity against Fungal Root Pathogens ▿

    Science.gov (United States)

    Barahona, Emma; Navazo, Ana; Martínez-Granero, Francisco; Zea-Bonilla, Teresa; Pérez-Jiménez, Rosa María; Martín, Marta; Rivilla, Rafael

    2011-01-01

    Motility is one of the most important traits for efficient rhizosphere colonization by Pseudomonas fluorescens F113rif (F113). In this bacterium, motility is a polygenic trait that is repressed by at least three independent pathways, including the Gac posttranscriptional system, the Wsp chemotaxis-like pathway, and the SadB pathway. Here we show that the kinB gene, which encodes a signal transduction protein that together with AlgB has been implicated in alginate production, participates in swimming motility repression through the Gac pathway, acting downstream of the GacAS two-component system. Gac mutants are impaired in secondary metabolite production and are unsuitable as biocontrol agents. However, the kinB mutant and a triple mutant affected in kinB, sadB, and wspR (KSW) possess a wild-type phenotype for secondary metabolism. The KSW strain is hypermotile and more competitive for rhizosphere colonization than the wild-type strain. We have compared the biocontrol activity of KSW with those of the wild-type strain and a phenotypic variant (F113v35 [V35]) which is hypermotile and hypercompetitive but is affected in secondary metabolism since it harbors a gacS mutation. Biocontrol experiments in the Fusarium oxysporum f. sp. radicis-lycopersici/Lycopersicum esculentum (tomato) and Phytophthora cactorum/Fragaria vesca (strawberry) pathosystems have shown that the three strains possess biocontrol activity. Biocontrol activity was consistently lower for V35, indicating that the production of secondary metabolites was the most important trait for biocontrol. Strain KSW showed improved biocontrol compared with the wild-type strain, indicating that an increase in competitive colonization ability resulted in improved biocontrol and that the rational design of biocontrol agents by mutation is feasible. PMID:21685161

  11. Pseudomonas fluorescens F113 mutant with enhanced competitive colonization ability and improved biocontrol activity against fungal root pathogens.

    Science.gov (United States)

    Barahona, Emma; Navazo, Ana; Martínez-Granero, Francisco; Zea-Bonilla, Teresa; Pérez-Jiménez, Rosa María; Martín, Marta; Rivilla, Rafael

    2011-08-01

    Motility is one of the most important traits for efficient rhizosphere colonization by Pseudomonas fluorescens F113rif (F113). In this bacterium, motility is a polygenic trait that is repressed by at least three independent pathways, including the Gac posttranscriptional system, the Wsp chemotaxis-like pathway, and the SadB pathway. Here we show that the kinB gene, which encodes a signal transduction protein that together with AlgB has been implicated in alginate production, participates in swimming motility repression through the Gac pathway, acting downstream of the GacAS two-component system. Gac mutants are impaired in secondary metabolite production and are unsuitable as biocontrol agents. However, the kinB mutant and a triple mutant affected in kinB, sadB, and wspR (KSW) possess a wild-type phenotype for secondary metabolism. The KSW strain is hypermotile and more competitive for rhizosphere colonization than the wild-type strain. We have compared the biocontrol activity of KSW with those of the wild-type strain and a phenotypic variant (F113v35 [V35]) which is hypermotile and hypercompetitive but is affected in secondary metabolism since it harbors a gacS mutation. Biocontrol experiments in the Fusarium oxysporum f. sp. radicis-lycopersici/Lycopersicum esculentum (tomato) and Phytophthora cactorum/Fragaria vesca (strawberry) pathosystems have shown that the three strains possess biocontrol activity. Biocontrol activity was consistently lower for V35, indicating that the production of secondary metabolites was the most important trait for biocontrol. Strain KSW showed improved biocontrol compared with the wild-type strain, indicating that an increase in competitive colonization ability resulted in improved biocontrol and that the rational design of biocontrol agents by mutation is feasible.

  12. The biocontrol endophytic bacterium Pseudomonas fluorescens PICF7 induces systemic defense responses in aerial tissues upon colonization of olive roots

    Directory of Open Access Journals (Sweden)

    Carmen eGómez-Lama Cabanás

    2014-09-01

    Full Text Available Pseudomonas fluorescens PICF7, a native olive root endophyte and effective biocontrol agent (BCA against Verticillium wilt of olive, is able to trigger a broad range of defense responses in root tissues of this woody plant. In order to elucidate whether strain PICF7 also induces systemic defense responses in above-ground organs, aerial tissues of olive plants grown under non-gnotobiotic conditions were collected at different time points after root bacterization with this endophytic BCA. A suppression subtractive hybridization (SSH cDNA library, enriched in up-regulated genes, was generated. This strategy enabled the identification of 376 ESTs (99 contigs and 277 singlets, many of them related to response to different stresses. Five ESTs, involved in defense responses, were selected to carry out time-course quantitative real-time PCR (qRT-PCR experiments aiming to: (i validate the induction of these genes, and (ii shed light on their expression pattern along time (from 1 to 15 days. Induction of olive genes potentially coding for lypoxigenase 2, catalase, 1-aminocyclopropane-1-carboxylate oxidase and phenylananine ammonia-lyase was thus confirmed at some time points. Computational analysis also revealed that different transcription factors were up-regulated in olive aerial tissues (i.e. jerf, bHLH, WRKYs, as previously reported for roots. Results confirmed that root colonization by this endophytic bacterium does not only trigger defense responses in this organ but also mount a wide array of systemic defense responses in distant tissues (stems, leaves. This sheds light on how olive plants respond to the ‘non-hostile’ colonization by a bacterial endophyte and how induced defense response can contribute to the biocontrol activity of strain PICF7.

  13. Xylanase B and an arabinofuranosidase from Pseudomonas fluorescens subsp. cellulosa contain identical cellulose-binding domains and are encoded by adjacent genes.

    OpenAIRE

    Kellett, L E; Poole, D M; Ferreira, L M; Durrant, A J; Hazlewood, G P; Gilbert, H J

    1990-01-01

    The complete nucleotide sequence of the Pseudomonas fluorescens subsp. cellulosa xynB gene, encoding an endo-beta-1,4-xylanase (xylanase B; XYLB) has been determined. The structural gene consists of an open reading frame (ORF) of 1775 bp coding for a protein of Mr 61,000. A second ORF (xynC) of 1712 bp, which starts 148 bp downstream of xynB, encodes a protein, designated xylanase C (XYLC), of Mr 59,000. XYLB hydrolyses oat spelt xylan to xylobiose and xylose, whereas XYLC releases only arabi...

  14. Characterization of an Endoglucanase from Pseudomonas fluorescens subsp. cellulosa Produced in Escherichia coli and Regulation of the Expression of Its Cloned Gene.

    OpenAIRE

    Lejeune, André; Courtois, Stéphane; Colson, Charles

    1988-01-01

    Several enzymatic properties of an endoglucanase produced in Escherichia coli by a gene from Pseudomonas fluorescens subsp. cellulosa were investigated. Gel filtration revealed a single peak of M(r) 36,000 with endoglucanase activity. The pH optimum of the enzyme was 7.0. Carboxymethyl cellulose and barley beta-glucan (mixed beta-1,3 and 1,4 linkages) were good substrates, but not laminarin (beta-1,3 linkages), amylose, filter paper, microcrystalline cellulose (Avicel), or cellotriose. The mo...

  15. Safety of spray-dried powder formulated Pseudomonas fluorescens strain CL145A exposure to subadult/adult unionid mussels during simulated open-water treatments

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Waller, Diane L.; Wise, Jeremy K.; Mayer, Denise A.; Aloisi, Douglas B.

    2015-01-01

    The exposure effects of a commercially prepared spray dried powder (SDP) formulation ofPseudomonas fluorescens (strain CL145A) on the survival of seven species of unionid mussels endemic to the Great Lakes and Mississippi River basins was evaluated in this study. The study exposures were completed within replicated 350-liter test tanks contained within a mobile bioassay laboratory sited on the shores of the Black River near La Crosse, Wisconsin. The test tanks were supplied with flowing, filtered river water which was interrupted during the exposure period.

  16. Quantitative and qualitative variability of the caseinolytic potential of different strains of Pseudomonas fluorescens: implications for the stability of casein micelles of UHT milks during their storage.

    Science.gov (United States)

    Baglinière, François; Tanguy, Gaëlle; Jardin, Julien; Matéos, Aurélie; Briard, Valérie; Rousseau, Florence; Robert, Benoît; Beaucher, Eric; Humbert, Gérard; Dary, Annie; Gaillard, Jean Luc; Amiel, Caroline; Gaucheron, Frédéric

    2012-12-15

    Pseudomonas fluorescens grows at low temperature and produces thermo-resistant protease(s) that can destabilize UHT (Ultra High Temperature) milk during its storage. The consequences of contamination of microfiltered milk with 9 strains of P. fluorescens on the stability of the corresponding UHT milk during storage had been investigated in this study. The strains were classified in two groups according to their ability to destabilize UHT milk. For the group of highly destabilizing strains, sedimentations of UHT milks, low values to phosphate test and the presence of aggregates were observed. Zeta potential and hydration of casein micelles decreased, whereas non casein nitrogen (NCN) and non protein nitrogen (NPN) contents increased. The analyses of NCN fraction by liquid chromatography coupled to mass spectrometry indicated that the different casein molecules were hydrolyzed in a similar way for the destabilizing strains suggesting that the same enzyme was implicated. For the group of slightly or not destabilizing strains no visual and biochemical alteration were found. This study showed that destabilization of UHT milk by P. fluorescens was highly variable and strain-dependent. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Investigating the ability of Pseudomonas fluorescens UW4 to reduce cadmium stress in Lactuca sativa via an intervention in the ethylene biosynthetic pathway.

    Science.gov (United States)

    Albano, Lucas J; Macfie, Sheila M

    2016-12-01

    A typical plant response to any biotic or abiotic stress, including cadmium (Cd), involves increased ethylene synthesis, which causes senescence of the affected plant part. Stressed plants can experience reduced ethylene and improved growth if they are inoculated with bacteria that have the enzyme ACC deaminase, which metabolizes the ethylene precursor ACC (1-aminocyclopropane-1-carboxylate). We investigated whether one such bacterium, Pseudomonas fluorescens UW4, reduces the production of ethylene and improves the growth of lettuce (Lactuca sativa) sown in Cd-contaminated potting material (PRO-MIX® BX). Plants were inoculated with the wild-type P. fluorescens UW4 or a mutant strain that cannot produce ACC deaminase. Cadmium-treated plants contained up to 50 times more Cd than did control plants. In noninoculated plants, Cd induced a 5-fold increase in ethylene concentration. The wild-type bacterium prevented Cd-induced reductions in root biomass but there was no relationship between Cd treatment and ethylene production in inoculated plants. In contrast, when the concentration of ethylene was plotted against the extent of bacterial colonization of the roots, increased colonization with wild-type P. fluorescens UW4 was associated with 20% less ethylene production. Ours is the first study to show that the protective effect of this bacterium is proportional to the quantity of bacteria on the root surface.

  18. Colonization process of olive tissues by Verticillium dahliae and its in planta interaction with the biocontrol root endophyte Pseudomonas fluorescens PICF7

    Science.gov (United States)

    Prieto, Pilar; Navarro‐Raya, Carmen; Valverde‐Corredor, Antonio; Amyotte, Stefan G.; Dobinson, Katherine F.; Mercado‐Blanco, Jesús

    2009-01-01

    Summary The colonization process of Olea europaea by the defoliating pathotype of Verticillium dahliae, and the in planta interaction with the endophytic, biocontrol strain Pseudomonas fluorescens PICF7 were determined. Differential fluorescent protein tagging was used for the simultaneous visualization of P. fluorescens PICF7 and V. dahliae in olive tissues. Olive plants were bacterized with PICF7 and then transferred to V. dahliae‐infested soil. Monitoring olive colonization events by V. dahliae and its interaction with PICF7 was conducted using a non‐gnotobiotic system, confocal laser scanner microscopy and tissue vibratoming sections. A yellow fluorescently tagged V. dahliae derivative (VDAT‐36I) was obtained by Agrobacterium tumefaciens‐mediated transformation. Isolate VDAT‐36I quickly colonized olive root surface, successfully invaded root cortex and vascular tissues via macro‐ and micro‐breakages, and progressed to the aerial parts of the plant through xylem vessel cells. Strain PICF7 used root hairs as preferred penetration site, and once established on/in root tissues, hindered pathogen colonization. For the first time using this approach, the entire colonization process of a woody plant by V. dahliae is reported. Early and localized root surface and root endophytic colonization by P. fluorescens PICF7 is needed to impair full progress of verticillium wilt epidemics in olive. PMID:21255281

  19. PRODUCTION AND CHARACTERIZATION OF BIOSURFACTANT BY Pseudomonas fluorescens USING CASSAVA FLOUR WASTEWATER AS MEDIA

    Directory of Open Access Journals (Sweden)

    Venty Suryanti

    2013-12-01

    Full Text Available Biosurfactant with efficient emulsification properties could be produced by Pseudomonas flourescens using cassava flour wastewater (manipueira as media. The ability of P. flourescens to produce biosurfactant could suggest potential use in industrial and environmental applications. Media containing a mixture of natural manipueira and nutrient broth with 48 h fermentation was the optimum condition for the biosurfactant production. Based on UV-Vis and FT-IR spectra, the biosurfactant was indicated as rhamnolipids containing hydroxyl, ester, carboxylic and aliphatic carbon chain functional groups. Biosurfactant exhibited critical micelle concentration (CMC value of 715 mg/L and reduced the surface tension of the water from 80 mN/m to 59 mN/m. The biosurfactant was able to decrease the interfacial tension about 51-70% when benzyl chloride, palm oil and kerosene were used as water-immiscible compounds. The biosurfactant was able to form stable emulsion until 30 days when paraffin, soybean oil, lubricant oil and kerosene were used as water-immiscible compounds.

  20. Factors screening to statistical experimental design of racemic atenolol kinetic resolution via transesterification reaction in organic solvent using free Pseudomonas fluorescens lipase.

    Science.gov (United States)

    Agustian, Joni; Kamaruddin, Azlina Harun; Aboul-Enein, Hassan Y

    2017-07-01

    As the (R)-enantiomer of racemic atenolol has no β-blocking activity and no lack of side effects, switching from the racemate to the (S)-atenolol is more favorable. Transesterification of racemic atenolol using free enzymes investigated as a resource to resolve the racemate via this method is limited. Screenings of enzyme, medium, and acetyl donor were conducted first to give Pseudomonas fluorescens lipase, tetrahydrofuran, and vinyl acetate. A statistical design of the experiment was then developed using Central Composite Design on some operational factors, which resulted in the conversions of 11.70-61.91% and substrate enantiomeric excess (ee) of 7.31-100%. The quadratic models are acceptable with R 2 of 95.13% (conversion) and 89.63% (ee). The predicted values match the observed values reasonably well. Temperature, agitation speed, and substrate molar ratio factor have low effects on conversion and ee, but enzyme loading affects the responses highly. The interaction of temperature-agitation speed and temperature-substrate molar ratio show significant effects on conversion, while temperature-agitation speed, temperature-substrate molar ratio, and agitation speed-substrate molar ratio affect ee highly. Optimum conditions for the use of Pseudomonas fluorescens lipase, tetrahydrofuran, and vinyl acetate were found at 45°C, 175 rpm, 2000 U, and 1:3.6 substrate molar ratio. © 2017 Wiley Periodicals, Inc.

  1. Molecular epidemiological survey of bacteremia by multidrug resistant Pseudomonas aeruginosa: the relevance of intrinsic resistance mechanisms.

    Directory of Open Access Journals (Sweden)

    Raquel Cristina Cavalcanti Dantas

    Full Text Available The bacterial factors associated with bacteremia by multidrug-resistant and extensively drug-resistant P. aeruginosa, including overexpression of efflux pumps, AmpC overproduction, and loss/alteration of the OprD porin in isolates that are non-Metallo-β-Lactamase producing were analyzed in a retrospective study. Molecular analyses included strain typing by Pulsed Field Gel Electrophoresis and identification of key genes via qualitative and quantitative PCR-based assays. Previous use of carbapenems and tracheostomy was independently associated with the development of bacteremia by extensively drug-resistant and multidrug-resistant strains of P. aeruginosa. A high consumption of antimicrobials was observed, and 75.0% of the isolates contained amplicons with the blaSPM-1 and blaVIM genes. Of the 47 non-Metallo-β-Lactamase isolates, none had another type of carbapenemase. However, the isolates exhibited high rates of hyperproduction of AmpC, loss of the OprD porin (71.4% and the presence of MexABOprM (57.1% and MexXY (64.3%. This study suggests that in non-Metallo-β-Lactamase isolates, the association of intrinsic resistance mechanisms could contributes to the expression of multidrug-resistant/extensively drug-resistant phenotypes.

  2. A full-length Plasmodium falciparum recombinant circumsporozoite protein expressed by Pseudomonas fluorescens platform as a malaria vaccine candidate.

    Directory of Open Access Journals (Sweden)

    Amy R Noe

    Full Text Available The circumsporozoite protein (CSP of Plasmodium falciparum is a major surface protein, which forms a dense coat on the sporozoite's surface. Preclinical research on CSP and clinical evaluation of a CSP fragment-based RTS, S/AS01 vaccine have demonstrated a modest degree of protection against P. falciparum, mediated in part by humoral immunity and in part by cell-mediated immunity. Given the partial protective efficacy of the RTS, S/AS01 vaccine in a recent Phase 3 trial, further improvement of CSP-based vaccines is crucial. In this report, we describe the preclinical development of a full-length, recombinant CSP (rCSP-based vaccine candidate against P. falciparum malaria suitable for current Good Manufacturing Practice (cGMP production. Utilizing a novel high-throughput Pseudomonas fluorescens expression platform, we demonstrated greater efficacy of full-length rCSP as compared to N-terminally truncated versions, rapidly down-selected a promising lead vaccine candidate, and developed a high-yield purification process to express immunologically active, intact antigen for clinical trial material production. The rCSP, when formulated with various adjuvants, induced antigen-specific antibody responses as measured by enzyme-linked immunosorbent assay (ELISA and immunofluorescence assay (IFA, as well as CD4+ T-cell responses as determined by ELISpot. The adjuvanted rCSP vaccine conferred protection in mice when challenged with transgenic P. berghei sporozoites containing the P. falciparum repeat region of CSP. Furthermore, heterologous prime/boost regimens with adjuvanted rCSP and an adenovirus type 35-vectored CSP (Ad35CS showed modest improvements in eliciting CSP-specific T-cell responses and anti-malarial protection, depending on the order of vaccine delivery. Collectively, these data support the importance of further clinical development of adjuvanted rCSP, either as a stand-alone product or as one of the components in a heterologous prime

  3. Removal of aldrin, dieldrin, heptachlor, and heptachlor epoxide using activated carbon and/or Pseudomonas fluorescens free cell cultures.

    Science.gov (United States)

    Bandala, Erick R; Andres-Octaviano, Juan; Pastrana, Paulino; Torres, Luis G

    2006-01-01

    Degradation of aldrin (1,2,3,4,10,10-Hexachloro-1,4,4a,5,8,8a-hexahydro-1,4:5-8-dimethanonaphthalene), heptachlor (1H-1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-methano indene), dieldrin (1aalpha,2beta,2aalpha,3beta,6beta,6aalpha,7beta,7aalpha)-3,4,5,6,9,9-Hexachloro-1a,2,2a,3,6,6a,7,7a-octahydro-2,7:3,6-d-methanonaphtha[2,3-b]oxirene, and heptachlor epoxide (1aalpha, 1bbeta,2alpha,5alpha,5alphabeta,6beta,6aalpha-2,3,4,5,6,7,7-Heptachloro-1a,1b,5,5a,6,6a-hexahydro-2,5-methano-2H-inden[1,2-b]-oxirene) was tested using free cultures of Pseudomonas fluorescens under controlled conditions. Pesticide concentrations were monitored by gas chromatography during 120 h. Percentages of degradation and biodegradation rates (BDR) were calculated. Data showed a trend suggesting a relation between chemical structure and degradability. Degradation kinetics for each pesticide tested showed that the highest degradation rates were found in the first 24 h. Kinetics data were adjusted to an empirical equation in order to predict their behavior, and the correlation coefficients obtained were satisfactory. Gas chromatography/mass spectrometry (GC/MS) analysis of the final extracts allowed the identification of chlordene and monodechlorodieldrin, which have been reported as final metabolite produced in the biodegradation of this kind of compounds. Regarding adsorption of pesticides on activated vegetal carbon, we concluded that removal efficiencies between 95.45 and 97.18% can be reached, depending on the pesticide and the carbon dose applied. The values for K from the Freundlich equation were quite similar for the four pesticides (between 1.0001 and 1.04), whereas the n values were quite different for each pesticide in the following order of affinity: dieldrin > aldrin > heptachlor epoxide > heptachlor. Equilibrium times, very important for scaling up the process, were between 43 min and 1 h, for the heptachlor epoxide and the heptachlor, respectively.

  4. A comparison between Pseudomonas aureofaciens (chlororaphis and P. fluorescens in biological control of cotton seedling damping-off disease

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    Samaneh Samavat

    2014-07-01

    Full Text Available Due to the importance of the biological control of plant diseases, testing and introducing new biocontrol-active microorganisms is a major concern among plant pathologists. The causal agent of cotton seedling damping-off disease is Rhizoctonia solani. In this regard, we tried to investigate the antagonistic activities of Pseudomonas aureofaciens (chlororaphis 30–84 (phenazine producing wild type and non-phenazine producing mutant strains on R. solani, in comparison with some isolates of P. fluorescent under both in vitro (laboratory and in vivo (greenhouse conditions. In the laboratory experiment, the inhibitory effects of all the bacteria, on the growth of R. solani, were evaluated using the dual culture procedure. Results showed that five isolates of P. fluorescent along with both strains of P. aureofaciens significantly inhibited the growth of R. solani. Effective bacterial antagonists were then evaluated in a greenhouse experiment where cotton seeds were coated with their suspensions and were sown in pasteurised field-soil. The soil had been pre-inoculated with a virulent isolate of R. solani. The efficacy of the bacterial antagonists was evaluated by counting the number of surviving seedlings in different treatments, at 15 and 60 days after sowing, for determining pre- and post-emergence damping-off incidence. According to the results of the greenhouse experiment, at both intervals, two isolates of P. fluorescens along with both strains of P. aureofaciens caused significant increases in the number of healthy seedlings, in comparison with the untreated control, and a commonly used fungicide (carboxin-thiram. The efficacy of phenazine producing a wild type strain of P. aureofaciens was higher than its non-phenazine producing mutant, indicating that phenazine plays an important role in the antagonistic activity of P. aureofaciens. Effective bacterial antagonists were then studied for their antagonistic mechanisms. The results showed that all

  5. Genome Analysis of Pseudomonas fluorescens PCL1751: A Rhizobacterium that Controls Root Diseases and Alleviates Salt Stress for Its Plant Host.

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    Shu-Ting Cho

    Full Text Available Pseudomonas fluorescens PCL1751 is a rod-shaped Gram-negative bacterium isolated from the rhizosphere of a greenhouse-grown tomato plant in Uzbekistan. It controls several plant root diseases caused by Fusarium fungi through the mechanism of competition for nutrients and niches (CNN. This mechanism does not rely on the production of antibiotics, so it avoids the concerns of resistance development and is environmentally safe. Additionally, this bacterium promotes plant growth by alleviating salt stress for its plant host. To investigate the genetic mechanisms that may explain these observations, we determined the complete genome sequence of this bacterium, examined its gene content, and performed comparative genomics analysis with other Pseudomonas strains. The genome of P. fluorescens PCL1751 consisted of one circular chromosome that is 6,143,950 base-pairs (bp in size; no plasmid was found. The annotation included 19 rRNA, 70 tRNA, and 5,534 protein-coding genes. The gene content analysis identified a large number of genes involved in chemotaxis and motility, colonization of the rhizosphere, siderophore biosynthesis, and osmoprotectant production. In contrast, the pathways involved in the biosynthesis of phytohormones or antibiotics were not found. Comparison with other Pseudomonas genomes revealed extensive variations in their genome size and gene content. The presence and absence of secretion system genes were highly variable. As expected, the synteny conservation among strains decreased as a function of phylogenetic divergence. The integration of prophages appeared to be an important driver for genome rearrangements. The whole-genome gene content analysis of this plant growth-promoting rhizobacterium (PGPR provided some genetic explanations to its phenotypic characteristics. The extensive and versatile substrate utilization pathways, together with the presence of many genes involved in competitive root colonization, provided further support

  6. Kynureninase-Type enzymes of Penicillum roqueforti, Aspergillus niger, Rhizopus stolonifer, and Pseudomonas fluorescens: further evidence for distinct kynureninase and hydroxykynureninase activities.

    Science.gov (United States)

    Shetty, A S; Gaertner, F H

    1975-04-01

    The kynureninase-type enzymes of three fungi and one bacterium were isolated and examined kinetically for their ability to catalyze the hydrolysis of L-kynurenine and L-3-hydroxykynurenine. The phycomycete Rhizopus stolonifer was found to contain a single, constitutive enzyme with Km for L-3-hydroxykynurenine and L-kynurenine of 6.67 times 10-minus 6 and 2.5 times 10-minus 4 M, respectively. The ascomycetes Aspergillus niger and Penicillium roqueforti each contain an enzyme, induced by L-tryptophan, with similar Km for L-3-hydroxykynurenine and L-kynurenine ranging from 5.9 times 10-minus 5 to 14.3 times 10-minus 5 M, as well as a constitutive enzyme with Km for the two substrates of similar to 4 times 10-minus 6 M and 10-minus 4 M. The bacterium Pseudomonas fluorescens has a single, inducible enzyme with Km for L-3-hydroxykynurenine and L-kynurenine of 5 times 10-minus 4 and 7 times 10-minus 5 M. In addition, significant differences in maximal velocities (Vmax) were observed in two cases. The Vmax of the inducible activity from P. fluorescens was 4.5 times greater for L-kynurenine than L-3-hydroxykynurenine, whereas the Vmax of the constitutive activity from R. stolonifer was 2.5 times greater for L-3-hydroxykynurenine. It is concluded (i) that the constitutive activities are hydroxykynureninases involved in the biosynthesis of nicotinamide adenine dinucleotide from L-tryptophan, (ii) that the inducible activities are kynureninases involved in the catabolism of L-tryptophan to anthranilate, and (iii) that R. stolonifer and P. fluorescens, respectively, carry the most specific examples of each type of enzyme.

  7. Expression of the translocator protein (TSPO from Pseudomonas fluorescens Pfo-1 requires the stress regulatory sigma factors AlgU and RpoH

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    Charlène eLeneveu-Jenvrin

    2015-09-01

    Full Text Available The translocator protein (TSPO, previously designated as peripheral-type benzodiazepine receptor, is an evolutionary conserved protein that is found in many Eukarya, Archae and Bacteria, in which it plays several important functions including for example membrane biogenesis, signaling and stress response. A tspo homologue gene has been identified in several members of the Pseudomonas genus, among which the soil bacterium P. fluorescens Pf0-1. In this bacterium, the tspo gene is located in the vicinity of a putative hybrid histidine kinase-encoding gene. Since tspo has been involved in water stress related response in plants, we explored the effects of hyperosmolarity and temperature on P. fluorescens Pf0-1 tspo expression using a strategy based on lux-reporter fusions. We show that the two genes Pfl01_2810 and tspo are co-transcribed forming a transcription unit. The expression of this operon is growth phase-dependent and is increased in response to high concentrations of NaCl, sucrose and to a D-cycloserine treatment, which are conditions leading to activity of the major cell wall stress responsive extracytoplasmic sigma factor AlgU. Interestingly, the promoter region activity is strongly lowered in a P. aeruginosa algU mutant, suggesting that AlgU may be involved at least partly in the molecular mechanism leading to Pfl01_2810-tspo expression. In silico analysis of this promoter region failed to detect an AlgU consensus binding site; however, we detect a putative binding site for the heat shock response RpoH sigma factor. Accordingly, the promoter activity of the region containing this sequence is increased in response to high growth temperature and slightly lowered in a P. aeruginosa rpoH mutant strain. Taken together, our data suggest that P. fluorescens tspo gene may belong at least partly to the cell wall stress response.

  8. Pseudomonas fluorescens ATCC 13525 containing an artificial oxalate operon and Vitreoscilla hemoglobin secretes oxalic acid and solubilizes rock phosphate in acidic alfisols.

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    Kavita Yadav

    Full Text Available Oxalate secretion was achieved in Pseudomonas fluorescens ATCC 13525 by incorporation of genes encoding Aspergillus niger oxaloacetate acetyl hydrolase (oah, Fomitopsis plaustris oxalate transporter (FpOAR and Vitreoscilla hemoglobin (vgb in various combinations. Pf (pKCN2 transformant containing oah alone accumulated 19 mM oxalic acid intracellularly but secreted 1.2 mM. However, in the presence of an artificial oxalate operon containing oah and FpOAR genes in plasmid pKCN4, Pf (pKCN4 secreted 13.6 mM oxalate in the medium while 3.6 mM remained inside. This transformant solubilized 509 μM of phosphorus from rock phosphate in alfisol which is 4.5 fold higher than the Pf (pKCN2 transformant. Genomic integrants of P. fluorescens (Pf int1 and Pf int2 containing artificial oxalate operon (plac-FpOAR-oah and artificial oxalate gene cluster (plac-FpOAR-oah, vgb, egfp secreted 4.8 mM and 5.4 mM oxalic acid, released 329 μM and 351 μM P, respectively, in alfisol. The integrants showed enhanced root colonization, improved growth and increased P content of Vigna radiata plants. This study demonstrates oxalic acid secretion in P. fluorescens by incorporation of an artificial operon constituted of genes for oxalate synthesis and transport, which imparts mineral phosphate solubilizing ability to the organism leading to enhanced growth and P content of V. radiata in alfisol soil.

  9. Xylanase B and an arabinofuranosidase from Pseudomonas fluorescens subsp. cellulosa contain identical cellulose-binding domains and are encoded by adjacent genes.

    Science.gov (United States)

    Kellett, L E; Poole, D M; Ferreira, L M; Durrant, A J; Hazlewood, G P; Gilbert, H J

    1990-12-01

    The complete nucleotide sequence of the Pseudomonas fluorescens subsp. cellulosa xynB gene, encoding an endo-beta-1,4-xylanase (xylanase B; XYLB) has been determined. The structural gene consists of an open reading frame (ORF) of 1775 bp coding for a protein of Mr 61,000. A second ORF (xynC) of 1712 bp, which starts 148 bp downstream of xynB, encodes a protein, designated xylanase C (XYLC), of Mr 59,000. XYLB hydrolyses oat spelt xylan to xylobiose and xylose, whereas XYLC releases only arabinose from the same substrate. Thus XYLB is a typical xylanase and XYLC is an arabinofuranosidase. Both enzymes bind to crystalline cellulose (Avicel), but not to xylan. The nucleotide sequences between residues 114 and 931 of xynB and xynC were identical, as were amino acid residues 39-311 of XYLB and XYLC. This conserved sequence is reiterated elsewhere in the P. fluorescens subsp. cellulosa genome. Truncated derivatives of XYLB and XYLC, in which the conserved sequence had been deleted, retained catalytic activity, but did not exhibit cellulose binding. A hybrid gene in which the 5' end of xynC, encoding residues 1-110 of XYLC, was fused to the Escherichia coli pho A' gene (encodes mature alkaline phosphatase) directed the synthesis of a fusion protein which exhibited alkaline phosphatase activity and bound to cellulose.

  10. Characterization of an Endoglucanase from Pseudomonas fluorescens subsp. cellulosa Produced in Escherichia coli and Regulation of the Expression of Its Cloned Gene.

    Science.gov (United States)

    Lejeune, A; Courtois, S; Colson, C

    1988-02-01

    Several enzymatic properties of an endoglucanase produced in Escherichia coli by a gene from Pseudomonas fluorescens subsp. cellulosa were investigated. Gel filtration revealed a single peak of M(r) 36,000 with endoglucanase activity. The pH optimum of the enzyme was 7.0. Carboxymethyl cellulose and barley beta-glucan (mixed beta-1,3 and 1,4 linkages) were good substrates, but not laminarin (beta-1,3 linkages), amylose, filter paper, microcrystalline cellulose (Avicel), or cellotriose. The mode of action was typical of an "endo"-acting enzyme. Taken together, these properties do not correspond to those of any of the endoglucanases described in P. fluorescens subsp. cellulosa. Consequently, the gene was designated egIX. The enzyme was sensitive to end-product inhibition by cellobiose but was only moderately inhibited by glucose. The enzyme was formed constitutively in E. coli throughout the growth phase. Urea had no effect on endoglucanase synthesis, but glucose acted as a catabolite repressor. The formation of the enzyme in E. coli was partially dependent on cyclic AMP.

  11. The N-terminal region of an endoglucanase from Pseudomonas fluorescens subspecies cellulosa constitutes a cellulose-binding domain that is distinct from the catalytic centre.

    Science.gov (United States)

    Gilbert, H J; Hall, J; Hazlewood, G P; Ferreira, L M

    1990-05-01

    The substrate specificity of an endoglucanase (EGB) from Pseudomonas fluorescens subspecies cellulosa was determined. The enzyme was most active against barley beta-glucan, but showed significant activity against amorphous and crystalline cellulose. EGB was purified to homogeneity by affinity chromatography with crystalline cellulose (Avicel). The Mr of the purified enzyme was 50,000, which is in good agreement with the size of EGB deduced from the nucleotide sequence of the celB gene, coding for EGB. The N-terminal region of the mature form of EGB showed strong homology to another endoglucanase and to a xylanase expressed by the same organism; homologous sequences included highly conserved serine-rich regions. Truncated forms of celB, in which the gene sequence encoding the conserved domain had been deleted, directed the synthesis of a functional endoglucanase that did not bind to crystalline cellulose. This indicates that the conserved region of endoglucanases and xylanases expressed by P. fluorescens subsp. cellulosa constitutes a cellulose-binding domain, which is distinct from the active centre. The possible role of this substrate-binding region is discussed.

  12. Methylobacterium sp. resides in unculturable state in potato tissues in vitro and becomes culturable after induction by Pseudomonas fluorescens IMGB163.

    Science.gov (United States)

    Podolich, O; Laschevskyy, V; Ovcharenko, L; Kozyrovska, N; Pirttilä, A M

    2009-03-01

    To induce growth of endophytic bacteria residing in an unculturable state in tissues of in vitro-grown potato plantlets. To isolate and identify the induced bacteria and to localize the strains in tissues of in vitro-grown potato plantlets. The inoculation of in vitro-grown potato plants with Pseudomonas fluorescens IMBG163 led to induction of another bacterium, a pink-pigmented facultative methylotroph that was identified as Methylobacterium sp. using phylogenetic 16S rDNA approach. Two molecular methods were used for localizing methylobacteria in potato plantlets: PCR and in situ hybridization (ISH/FISH). A PCR product specific for the Methylobacterium genus was found in DNA isolated from the surface-sterilized plantlet leaves. Presence of Methylobacterium rRNA was detected by ISH/FISH in leaves and stems of inoculated as well as axenic potato plantlets although the bacterium cannot be isolated from the axenic plants. Methylobacterium sp. resides in unculturable state within tissues of in vitro-grown potato plants and becomes culturable after inoculation with P. fluorescens IMBG163. In order to develop endophytic biofertilizers and biocontrol agents, a detailed knowledge of the life-style of endophytes is essential. To our knowledge, this is the first report on increase of the culturability of endophytes in response to inoculation by nonpathogenic bacteria.

  13. Arabidopsis thaliana as a tool to identify traits involved in Verticillium dahliae biocontrol by the olive root endophyte Pseudomonas fluorescens PICF7

    Science.gov (United States)

    Maldonado-González, M. Mercedes; Bakker, Peter A. H. M.; Prieto, Pilar; Mercado-Blanco, Jesús

    2015-01-01

    The effective management of Verticillium wilts (VW), diseases affecting many crops and caused by some species of the soil-borne fungus Verticillium, is problematic. The use of microbial antagonists to control these pathologies fits modern sustainable agriculture criteria. Pseudomonas fluorescens PICF7 is an endophytic bacterium isolated from olive roots with demonstrated ability to control VW of olive caused by the highly virulent, defoliating (D) pathotype of Verticillium dahliae Kleb. However, the study of the PICF7-V. dahliae-olive tripartite interaction poses difficulties because of the inherent characteristics of woody, long-living plants. To overcome these problems we explored the use of the model plant Arabidopsis thaliana. Results obtained in this study showed that: (i) olive D and non-defoliating V. dahliae pathotypes produce differential disease severity in A. thaliana plants; (ii) strain PICF7 is able to colonize and persist in the A. thaliana rhizosphere but is not endophytic in Arabidopsis; and (iii) strain PICF7 controls VW in Arabidopsis. Additionally, as previously observed in olive, neither swimming motility nor siderophore production by PICF7 are required for VW control in A. thaliana, whilst cysteine auxotrophy decreased the effectiveness of PICF7. Moreover, when applied to the roots PICF7 controlled Botrytis cinerea infection in the leaves of Arabidopsis, suggesting that this strain is able to induce systemic resistance. A. thaliana is therefore a suitable alternative to olive bioassays to unravel biocontrol traits involved in biological control of V. dahliae by P. fluorescens PICF7. PMID:25904904

  14. Characterisation of the thermostable protease AprX in strains of Pseudomonas fluorescens and impact on the shelf-life of dairy products: preliminary results

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    Nadia Andrea Andreani

    2016-12-01

    Full Text Available Bacterial proteases are involved in food spoilage and shelf-life reduction. Among the bacterial proteases, a predominant role in spoilage of dairy products seems to be played by the thermostable metallo-protease AprX, which is produced by various strains of Pseudomonas fluorescens. Differences in AprX enzyme activity among different strains were highlighted, but the most proteolytic strains were not identified. In this study, the presence of the aprX gene was evaluated in 69 strains isolated from food matrices and 18 reference strains belonging to the P. fluorescens group, which had been previously typed by the multi locus sequence typing method. Subsequently, a subset of reference strains was inoculated in ultra-high temperature milk, and the expression of the aprX gene was evaluated at 22 and 6°C. On the same milk samples, the proteolytic activity was then evaluated through Azocasein and trinitrobenzenesulfonic acid solution assays. Finally, to assess the applicability of the former assay directly on dairy products the proteolityc activity was tested on industrial ricotta samples using the Azocasein assay. These results demonstrate the spread of aprX gene in most strains tested and the applicability of Azocasein assay to monitor the proteolytic activity in dairy products.

  15. Non-target trials with Pseudomonas fluorescens strain CL145A, a lethal control agent of dreissenid mussels (Bivalvia: Dreissenidae

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    Daniel P. Molloy

    2013-01-01

    Full Text Available In an effort to develop an efficacious and environmentally safe method for managing zebra mussels (Dreissena polymorpha and quaggamussels (Dreissena rostriformis bugensis, we initiated a research project investigating the potential use of bacteria and their naturalmetabolic products as biocontrol agents. This project resulted in the discovery of an environmental isolate lethal to dreissenid mussels,Pseudomonas fluorescens strain CL145A (Pf-CL145A. In previous published reports we have demonstrated that: 1 Pf-CL145A’s mode ofaction is intoxication (not infection; 2 natural product within ingested bacterial cells lyse digestive tract epithelial cells leading to dreisseniddeath; and 3 high dreissenid kill rates (>90% are achievable following treatment with Pf-CL145A cells, irrespective of whether thebacterial cells are dead or alive. Investigating the environmental safety of Pf-CL145A was also a key element in our research efforts, andherein, we report the results of non-target trials demonstrating Pf-CL145A’s high specificity to dreissenids. These acute toxicity trials weretypically single-dose, short-term (24-72 h exposures to Pf-CL145A cells under aerated conditions at concentrations highly lethal todreissenids (100 or 200 mg/L. These trials produced no evidence of mortality among the ciliate Colpidium colpoda, the cladoceran Daphniamagna, three fish species (Pimephales promelas, Salmo trutta, and Lepomis macrochirus, and seven bivalve species (Mytilus edulis,Pyganodon grandis, Pyganodon cataracta, Lasmigona compressa, Strophitus undulatus, Lampsilis radiata, and Elliptio complanata. Lowmortality (3-27% was recorded in the amphipod Hyalella azteca, but additional trials suggested that most, if not all, of the mortality couldbe attributed to some other unidentified factor (e.g., possibly particle load or a water quality issue rather than Pf-CL145A’s dreissenidkillingnatural product. In terms of potential environmental safety, the results of

  16. Non-target effects of the microbial control agents Pseudomonas fluorescens DR54 and Clonostachys rosea IK726 in soils cropped with barley followed by sugar beet

    DEFF Research Database (Denmark)

    Johansen, Anders; Knudsen, Inge M.B.; Binnerup, Svend J.

    2005-01-01

    Non-target effects of a bacterial (Pseudomonas fluorescens DR54) and a fungal (Clonostachys rosea IK726) microbial control agent (MCA), on the indigenous microbiota in bulk soil and rhizosphere of barley, and subsequent a sugar beet crop, were studied in a greenhouse experiment. MCAs were...... by a factor of 106 and 20, respectively, and DR54 showed a short-lasting growth increase in the sugar beet rhizosphere. In general, the non-target effects were small and transient. IK726 seemed to have general stimulating effects on soil enzyme activity and the soil microbiota, and resulted in a significant...... introduced by seed and soil inoculation. Bulk and rhizosphere soils were sampled regularly during the growth of barley and sugar beet. The soils were assayed for the fate of MCAs and various features of the indigenous soil microbiota. At the end of the experiment (193 d), DR54 and IK726 had declined...

  17. Investigation of zoonotic disease pathogens (Aeromonas hydrophila, Pseudomonas fluorescens, Streptococcus iniae) seen in carp farms in the Northern Iraq-Erbil region by molecular methods

    Science.gov (United States)

    Ibraheem, Azad Saber; Önalan, Şükrü; Arabacı, Muhammed

    2017-04-01

    The aim of this study was to determine the zoonotic bacteria in carp farms in the Northern Iraq-Erbil region. Carp is the main fish species cultured in Erbil region. The most common zoonotic bacteria generally seen in carp farms are Aeromonas hydrophila, Pseudomonas fluorescens and Streptococcus iniae. Samples were collected from 25 carp farms in the Northern Iraq-Erbil region. Six carp samples were collected from each carp farm. Head kidney and intestine tissue samples were collected from each carp sample. Then head kidney and intestine tissue samples were pooled separately from each carp farm. Total bacterial DNA had been extracted from the 25 pooled head kidney and 25 intestinal tissue samples. The pathogen Primers were originally designed from 16S RNA gene region. Zoonotic bacteria were scanned in all tissue samples with absent/present analysis by RT-PCR. Furthermore, the capillary gel electrophoresis bands were used for confirmation of amplicon size which was planned during primer designing stage. As a result, thirteen carp farms were positive in the respect to Aeromonas hydrophila, eight carp farms were positive from head kidney and six carp farms were positive from the intestine, only one carp farm was positive from both head kidney and the intestine tissue samples. In the respect to Streptococcus iniae, four carp farms were positive from head kidney and two carp farms were positive from the intestine. Only one carp farm was positive in the respect to Pseudomonas fluorescens from the intestine. Totally, 9 of 25 carp farms were cleared (negative) the zoonotic bacteria. In conclusion, the zoonotic bacteria were high (64 %) in carp farms in the Northern Iraq-Erbil region.

  18. Persistent Bacteremia from Pseudomonas aeruginosa with In Vitro Resistance to the Novel Antibiotics Ceftolozane-Tazobactam and Ceftazidime-Avibactam

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    Louie Mar Gangcuangco

    2016-01-01

    Full Text Available Ceftazidime-avibactam and ceftolozane-tazobactam are new antimicrobials with activity against multidrug-resistant Pseudomonas aeruginosa. We present the first case of persistent P. aeruginosa bacteremia with in vitro resistance to these novel antimicrobials. A 68-year-old man with newly diagnosed follicular lymphoma was admitted to the medical intensive care unit for sepsis and right lower extremity cellulitis. The patient was placed empirically on vancomycin and piperacillin-tazobactam. Blood cultures from Day 1 of hospitalization grew P. aeruginosa susceptible to piperacillin-tazobactam and cefepime identified using VITEK 2 (Biomerieux, Lenexa, KS. Repeat blood cultures from Day 5 grew P. aeruginosa resistant to all cephalosporins, as well as to meropenem by Day 10. Susceptibility testing performed by measuring minimum inhibitory concentration by E-test (Biomerieux, Lenexa, KS revealed that blood cultures from Day 10 were resistant to ceftazidime-avibactam and ceftolozane-tazobactam. The Verigene Blood Culture-Gram-Negative (BC-GN microarray-based assay (Nanosphere, Inc., Northbrook, IL was used to investigate underlying resistance mechanism in the P. aeruginosa isolate but CTX-M, KPC, NDM, VIM, IMP, and OXA gene were not detected. This case report highlights the well-documented phenomenon of antimicrobial resistance development in P. aeruginosa even during the course of appropriate antibiotic therapy. In the era of increasing multidrug-resistant organisms, routine susceptibility testing of P. aeruginosa to ceftazidime-avibactam and ceftolozane-tazobactam is warranted. Emerging resistance mechanisms to these novel antibiotics need to be further investigated.

  19. Clinical characteristics and outcomes of Pseudomonas aeruginosa bacteremia in febrile neutropenic children and adolescents with the impact of antibiotic resistance: a retrospective study.

    Science.gov (United States)

    Kim, Hyo Sup; Park, Bo Kyoung; Kim, Seong Koo; Han, Seung Beom; Lee, Jae Wook; Lee, Dong-Gun; Chung, Nack-Gyun; Cho, Bin; Jeong, Dae Chul; Kang, Jin Han

    2017-07-17

    Although the proportion of Pseudomonas aeruginosa infections has reduced after the introduction of antibiotics with anti-pseudomonal effects, P. aeruginosa bacteremia still causes high mortality in immunocompromised patients. This study determined the clinical characteristics and outcomes of P. aeruginosa bacteremia and the antibiotic susceptibilities of strains isolated from febrile neutropenic patients. Thirty-one febrile neutropenic children and adolescents with underlying hematologic/oncologic disorders diagnosed with P. aeruginosa bacteremia between 2011 and 2016 were enrolled in the study. Their medical records were retrospectively reviewed to evaluate the demographic and clinical characteristics. Antibiotic susceptibility rates of the isolated P. aeruginosa to eight antibiotic categories (anti-pseudomonal penicillin, anti-pseudomonal penicillin and β-lactamase inhibitor combination, anti-pseudomonal cephalosporin, monobactam, carbapenem, aminoglycoside, fluoroquinolone, and colistin) were also determined. Among the investigated factors, risk factors for mortality and infections by a multidrug-resistance (MDR) strain were determined. Thirty-six episodes of P. aeruginosa bacteremia were identified. The mean age of the enrolled patients was 9.5 ± 5.4 years, and 26 (72.2%) episodes occurred in boys. Acute myeloid leukemia (41.7%) and acute lymphoblastic leukemia (33.3%) were the most common underlying disorders. The 30-day mortality was 38.9%, and 36.1% of the episodes were caused by MDR strains. The deceased patients were more likely to experience breakthrough infection (P = 0.036) and bacteremia (P = 0.005) due to MDR strains when compared with the patients who survived. The survived patients more likely received appropriate empirical antibiotic therapy (P = 0.024) and anti-pseudomonal β-lactam and aminoglycoside combination therapy (P = 0.039) compared with the deceased patients. The antibiotic susceptibility rates of the isolated P. aeruginosa

  20. Influencia de la concentración salina y la temperatura en la composición de ácidos grasos de membrana de Pseudomonas fluorescens GNP-OHP-3 Influence of salinity and temperature on fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane

    Directory of Open Access Journals (Sweden)

    G. N. Pucci

    2004-03-01

    Full Text Available Las bacterias responden a los cambios ambientales modificando su composición, para evitar el daño que dichos cambios podrían ejercer. Una de las modificaciones más importantes es la variación de la composición de los ácidos grasos de las membranas celulares, que le permite mantener la homeoviscosidad ante situaciones de estrés. Trabajos previos han estudiado la acción de la temperatura, presión hidrostática y diferentes solventes sobre cepas de Pseudomonas putida. En este trabajo se estudió la acción conjunta de la temperatura y la salinidad sobre la composición de ácidos grasos de membranas celulares de Pseudomonas fluorescens GNP-OHP-3, una cepa bacteriana aislada de un hábitat contaminado con petróleo. Pseudomonas fluorescens GNP-OHP-3 respondió a las variaciones de temperatura modificando los ácidos grasos de sus membranas de manera similar a lo descripto en otros integrantes de su género: ante el aumento de temperatura se observó un incremento de ácidos grasos saturados y una disminución de los ácidos grasos insaturados. En el rango de concentraciones salinas ensayadas las variaciones de los ácidos grasos mayoritarios fueron en general erráticas. La respuesta de los ácidos grasos ciclo propano pudo expresarse con ecuaciones matemáticas que permitieron predecir el porcentaje de estos ácidos en relación a la concentración de cloruro de sodio.The bacteria respond to environmental changes modifying their composition. One of the most important modifications is the variation on fatty acid composition of cellular membranes to maintain the homeoviscosity. The action of temperature, hydrostatic pressure and solvents on Pseudomonas putida has been thoroughly studied. In this paper, the combined action of the temperature and salinity on fatty acid composition of cellular membranes of Pseudomonas fluorescens GNP-OHP-3, a bacterial strain isolated from a petroleum contaminated habitat, was studied. The modifications in the

  1. Development and validation of a real-time TaqMan assay for the detection and enumeration of Pseudomonas fluorescens ATCC 13525 used as a challenge organism in testing of food equipments.

    Science.gov (United States)

    Saha, Ratul; Bestervelt, Lorelle L; Donofrio, Robert S

    2012-02-01

    Pseudomonas fluorescens ATCC 13525 is used as the challenge organism to evaluate the efficacy of the clean-in-place (CIP) process of food equipment (automatic ice-maker) as per NSF/ANSI Standard 12. Traditional culturing methodology is presently used to determine the concentration of the challenge organism, which takes 48 h to confirm the cell density. Storage of the challenge preparation in the refrigerator might alter the cell density as P. fluorescens is capable of growing at 4 °C. Also, background organism can grow on the Pseudomonas F agar (PFA) used for the recovery of P. fluorescens thus affecting the results of the test. Real-time TaqMan assay targeting the cpn60 gene was developed for the enumeration and the identification of P. fluorescens because of its specificity, accuracy, and shorter turnaround time. The TaqMan primer-probe pair developed using the Allele ID® 7.0 probe design software was highly specific and sensitive for the target organism. The sensitivity of the assay was 10 colony forming units (CFU)/mL. The assay was also successful in determining the concentration of the challenge preparation within 2 h. Based on these observations, TaqMan assay targeting the cpn60 gene can be efficiently used for strain level identification and enumeration of bacteria. Pseudomonas fluorescens ATCC 13525 is used as a challenge organism in the efficacy testing of clean-in-place process of food equipments. Currently, culturing technique is used for its identification and estimation, which is not only time-consuming but also prone to error. Real-time TaqMan assay is more specific, sensitive, and accurate along with a shorter turnaround time compared to culturing techniques, thereby increasing the overall quality of the testing methodology to evaluate the clean-in-place process critical for the food industry to protect public health and safety. © 2012 Institute of Food Technologists®

  2. Proteinase production in Pseudomonas fluorescens ON2 is affected by carbon sources and allows surface-attached but not planktonic cells to utilize protein for growth in lake water

    DEFF Research Database (Denmark)

    Nicolaisen, Mette Haubjerg; Worm, Jakob; Jørgensen, Niels O. G.

    2012-01-01

    Proteins may be an important carbon and nitrogen source to bacteria in aquatic habitats, yet knowledge on the actual utilization of this substrate by proteolytic bacteria is scarce. In the present study, Pseudomonas fluorescens ON2 produced an alkaline proteinase (AprX) during growth and there wa......Proteins may be an important carbon and nitrogen source to bacteria in aquatic habitats, yet knowledge on the actual utilization of this substrate by proteolytic bacteria is scarce. In the present study, Pseudomonas fluorescens ON2 produced an alkaline proteinase (AprX) during growth...... the proteinase during growth unless a preferred carbon source like citrate is present. Lake water model systems were subsequently used to investigate the ability of proteolytic versus non-proteolytic ON2 strains to utilize protein for growth at moderate cell densities. Only cells forming surface-attached micro...

  3. Sequencing and Analysis of the Pseudomonas fluorescens GcM5-1A Genome: A Pathogen Living in the Surface Coat of Bursaphelenchus xylophilus.

    Directory of Open Access Journals (Sweden)

    Kai Feng

    Full Text Available It is known that several bacteria are adherent to the surface coat of pine wood nematode (Bursaphelenchus xylophilus, but their function and role in the pathogenesis of pine wilt disease remains debatable. The Pseudomonas fluorescens GcM5-1A is a bacterium isolated from the surface coat of pine wood nematodes. In previous studies, GcM5-1A was evident in connection with the pathogenicity of pine wilt disease. In this study, we report the de novo sequencing of the GcM5-1A genome. A 600-Mb collection of high-quality reads was obtained and assembled into sequence contigs spanning a 6.01-Mb length. Sequence annotation predicted 5,413 open reading frames, of which 2,988 were homologous to genes in the other four sequenced P. fluorescens isolates (SBW25, WH6, Pf0-1 and Pf-5 and 1,137 were unique to GcM5-1A. Phylogenetic studies and genome comparison revealed that GcM5-1A is more closely related to SBW25 and WH6 isolates than to Pf0-1 and Pf-5 isolates. Towards study of pathogenesis, we identified 79 candidate virulence factors in the genome of GcM5-1A, including the Alg, Fl, Waa gene families, and genes coding the major pathogenic protein fliC. In addition, genes for a complete T3SS system were identified in the genome of GcM5-1A. Such systems have proved to play a critical role in subverting and colonizing the host organisms of many gram-negative pathogenic bacteria. Although the functions of the candidate virulence factors need yet to be deciphered experimentally, the availability of this genome provides a basic platform to obtain informative clues to be addressed in future studies by the pine wilt disease research community.

  4. Application of Endophytic Pseudomonas fluorescens and a Bacterial Consortium to Brassica napus Can Increase Plant Height and Biomass under Greenhouse and Field Conditions

    Directory of Open Access Journals (Sweden)

    Richard D. Lally

    2017-12-01

    Full Text Available Plant associated bacteria with plant growth promotion (PGP properties have been proposed for use as environmentally friendly biofertilizers for sustainable agriculture; however, analysis of their efficacy in the field is often limited. In this study, greenhouse and field trials were carried out using individual endophytic Pseudomonas fluorescens strains, the well characterized rhizospheric P. fluorescens F113 and an endophytic microbial consortium of 10 different strains. These bacteria had been previously characterized with respect to their PGP properties in vitro and had been shown to harbor a range of traits associated with PGP including siderophore production, 1-aminocyclopropane-1-carboxylic acid (ACC deaminase activity, and inorganic phosphate solubilization. In greenhouse experiments individual strains tagged with gfp and Kmr were applied to Brassica napus as a seed coat and were shown to effectively colonize the rhizosphere and root of B. napus and in addition they demonstrated a significant increase in plant biomass compared with the non-inoculated control. In the field experiment, the bacteria (individual and consortium were spray inoculated to winter oilseed rape B. napus var. Compass which was grown under standard North Western European agronomic conditions. Analysis of the data provides evidence that the application of the live bacterial biofertilizers can enhance aspects of crop development in B. napus at field scale. The field data demonstrated statistically significant increases in crop height, stem/leaf, and pod biomass, particularly, in the case of the consortium inoculated treatment. However, although seed and oil yield were increased in the field in response to inoculation, these data were not statistically significant under the experimental conditions tested. Future field trials will investigate the effectiveness of the inoculants under different agronomic conditions.

  5. Arabidopsis thaliana as a tool to identify traits involved in Verticillium dahliae biocontrol by the olive root endophyte Pseudomonas fluorescens PICF7

    Directory of Open Access Journals (Sweden)

    M. Mercedes eMaldonado-González

    2015-04-01

    Full Text Available The effective management of Verticillium wilts, diseases affecting many crops and caused by some species of the soil-borne fungus Verticillium, is problematic. The use of microbial antagonists to control these pathologies fits modern sustainable agriculture criteria. Pseudomonas fluorescens PICF7 is an endophytic bacterium isolated from olive roots with demonstrated ability to control Verticillium wilt of olive caused by the highly-virulent, defoliating (D pathotype of Verticillium dahliae Kleb. However, the study of the PICF7-V.dahliae-olive tripartite interaction poses difficulties because of the inherent characteristics of woody, long-living plants. To overcome these problems we explored the use of the model plant Arabidopsis thaliana. Results obtained in this study showed that: (i olive D and non-defoliating (ND V. dahliae pathotypes produce differential disease severity in A. thaliana plants; (ii strain PICF7 is able to colonize and persist in the A. thaliana rhizosphere but is not endophytic in Arabidopsis; and (iii strain PICF7 controls Verticillium wilt (VW in Arabidopsis. Additionally, as previously observed in olive, neither swimming motility nor siderophore production by PICF7 are required for VW control in A. thaliana, whilst cysteine auxotrophy decreased the effectiveness of PICF7. Moreover, when applied to the roots PICF7 controlled Botrytis cinerea infection in the leaves of Arabidopsis, suggesting that this strain is able to induce systemic resistance. Arabidopsis thaliana is therefore a suitable alternative to olive bioassays to unravel biocontrol traits involved in biological control of V. dahliae by P. fluorescens PICF7.

  6. Influence of Arbuscular Mycorrhizal Fungi and Pseudomonas fluorescens at Different Superphosphate Levels on Linseed (Linum usitatissimum L. Growth Response Influencia de Hongos Micorriza Arbusculares y Pseudomonas fluorescens con Diferentes Niveles de Superfosfato sobre la Respuesta al Crecimiento de Lino (Linum usitatissimum L.

    Directory of Open Access Journals (Sweden)

    Neetu Neetu

    2012-06-01

    Full Text Available The aim of this study was to investigate the influence of arbuscular mycorrhizal fungi (AMF Glomus mosseae (T.H. Nicolson & Gerd. Gerd. & Trappe and Acaulospora laevis (Gerd. & Trappe on linseed (Linum usitatissimum L. growth response with phosphate solubilizing bacteria Pseudomonas fluorescens; different doses of superphosphate were used: 20 kg ha4 (half recommended dose, 40 kg ha4 (recommended dose, and 80 kg ha4 (double recommended dose in earthen pots filled with sterilized soil under greenhouse conditions. Among all the growth parameters, the following were the highest in the G. mosseae + P. fluorescens combination at the medium concentration (recommended superphosphate dose: plant height (78.74 ± 1.8 cm, fresh shoot weight (3.45 ± 0.294 g, dry shoot weight (0.57 ± 0.007 g, fresh root weight (0.223 ± 0.023 g, dry root weight (0.036 ± 0.004 g, root length (17.67 ± 0.48 cm, AM spore number (94.4 ± 9.86, shoot (1.14 ± 0.115% and root (1.29 ± 0.110% P content, and acidic (0.447 ± 0.012 IU g-1 FW and alkaline phosphatase activity (0.119 ± 0.008 IU g-1 FW. The percentage mycorrhizal root colonization with the A. laevis + P. fluorescens (86.86 ± 2.17% combination and chlorophyll content with the G. mosseae + A. laevis + P. fluorescens (0.474 ± 0.009 mg g-1 FW combination recorded the highest values at the low concentration (half recommended superphosphate dose as compared with non-mycorrhizal plants (control. The high superphosphate dose clearly reduced or decreased all the growth parameters. Therefore, vigorous growth and maximum flax yield can be achieved by inoculating plants with AM fungi and P. fluorescens with the recommended dose or less than the recommended dose of superphosphate.La presente investigation tuvo como objetivo estudiar la influencia de hongos micorrícicos arbusculares (AMF, i.e., Glomus mosseae (T.H. Nicolson & Gerd. Gerd. & Trappey Acaulospora laevis (Gerd. & Trappe, en la respuesta de crecimiento de lino

  7. Proteolytic activity of protease produced by Pseudomonas fluorescens IB 2312 in skimmed milk subject to the process of high pressure homogenization

    Directory of Open Access Journals (Sweden)

    Claudia Regina Gonçalves Pinho

    2014-08-01

    Full Text Available The presence of thermoresistant proteases produced by psychrotrophic microorganisms have been identified as a limiting factor of the UHT milk shelflife, causing undesirable changes in milk products. High pressure homogenization (HPH processing is a non-thermal method of food preservation, able to promotes the microbiological safety and inactivation of some enzymes. Thus, this work assessed the proteolytic activity of protease produced by Pseudomonas fluorescens in skim milk subjected to high pressure homogenization process. The milk samples were added by the protease enzymatic extract (10% v/v and subjected to pressures up to 300 MPa. The assays showed that pressures on the order of 300 MPa caused a 72.5% reduction in proteolytic activity. Therefore, the process at high pressures resulted in significant inactivation of this thermoresistent enzyme, which possibly favors the shelf-life extension of the UHT milk and also limits the yield and quality loss of cheeses due to undesirable sensory changes in flavor and texture caused by this enzyme.

  8. Immobilization of Pseudomonas fluorescens lipase on hydrophobic supports and application in biodiesel synthesis by transesterification of vegetable oils in solvent-free systems.

    Science.gov (United States)

    Lima, Lionete N; Oliveira, Gladson C; Rojas, Mayerlenis J; Castro, Heizir F; Da Rós, Patrícia C M; Mendes, Adriano A; Giordano, Raquel L C; Tardioli, Paulo W

    2015-04-01

    This work describes the preparation of biocatalysts for ethanolysis of soybean and babassu oils in solvent-free systems. Polystyrene, Amberlite (XAD-7HP), and octyl-silica were tested as supports for the immobilization of Pseudomonas fluorescens lipase (PFL). The use of octyl-silica resulted in a biocatalyst with high values of hydrolytic activity (650.0 ± 15.5 IU/g), immobilization yield (91.3 ± 0.3 %), and recovered activity (82.1 ± 1.5 %). PFL immobilized on octyl-silica was around 12-fold more stable than soluble PFL, at 45 °C and pH 8.0, in the presence of ethanol at 36 % (v/v). The biocatalyst provided high vegetable oil transesterification yields of around 97.5 % after 24 h of reaction using babassu oil and around 80 % after 48 h of reaction using soybean oil. The PFL-octyl-silica biocatalyst retained around 90 % of its initial activity after five cycles of transesterification of soybean oil. Octyl-silica is a promising support that can be used to immobilize PFL for subsequent application in biodiesel synthesis.

  9. Synthesis of amino-silane modified superparamagnetic Fe{sub 3}O{sub 4} nanoparticles and its application in immobilization of lipase from Pseudomonas fluorescens Lp1

    Energy Technology Data Exchange (ETDEWEB)

    Kanimozhi, S., E-mail: skanimo@gmail.com [Department of Biotechnology, Sathyabama University, Jeppiaar Nagar, Rajivgandhi Salai, Chennai 600119, Tamil Nadu (India); Perinbam, K. [Department of Plant Biology and Biotechnology, Nandanam Arts College (Men), Chennai 600035, Tamil Nadu (India)

    2013-05-15

    Highlights: ► Magnetic nanoparticles were synthesized by chemical co-precipitation method. ► Surface was functionalized with amino-silane and used for lipase immobilization. ► Characterized through TEM, SEM, XRD, FT-IR and VSM analysis. ► The functionalization and immobilization did not affect the magnetite properties. ► The immobilized lipase showed greater functional property than free lipase. - Abstract: Superparamagnetic nanoparticles (Fe{sub 3}O{sub 4}–magnetite) were prepared by chemical co-precipitation method and their surface was functionalized with 3-aminopropyltriethoxysilane via silanization reaction to obtain amino functionalized magnetic nanoparticles. The purified lipase from Pseudomonas fluorescens Lp1 was immobilized onto functionalized magnetite using glutaraldehyde as the coupling agent. The characterization of the nanoparticles was done by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, vibrating sample magnetometry and Fourier transformed infrared spectroscopy. The size of the magnetite was measured about 10–30 nm. The results of characterization study revealed the successful immobilization of lipase on to functionalized magnetite. The saturation magnetization of magnetic nanoparticles was found to be 28.34 emu/g whereas the immobilized magnetic nanoparticle was 17.074 emu/g. The immobilized lipase had greater activity at 50 °C and thermal stability upto 70 °C. It exhibited excellent reusability for 4 cycles and storage stability upto 15 days by retaining 75% of its initial activity.

  10. Efficacy of Pseudomonas fluorescens strain CL145A spray dried powder for controlling zebra mussels adhering to native unionid mussels within field enclosures

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Severson, Todd J.; Mayer, Denise A.

    2015-01-01

    The efficacy of a commercially prepared spray dried powder (SDP) formulation of Pseudomonas fluorescens (strain CL145A) was evaluated for removing zebra mussels (Dreissena polymorpha) adhering to a population of unionid mussels in Lake Darling (Alexandria, Minnesota). Two groups of unionid mussels were used in the study. Unionid mussels were collected near the test area, weighed, photographed, individually tagged, and randomly allocated to one of nine test enclosures in equal proportions and then divided into two groups. The first group of unionid mussels (Group 1, n = 5 per test enclosure) were indiscriminately selected from each test enclosure and used to estimate the number of zebra mussels adhering to unionid mussels prior to exposure. The second group of unionid mussels (Group 2, n = 22 per test enclosure) were used to evaluate the efficacy of SDP for removal of adhering zebra mussels. Both Group 1 and Group 2 mussels were used to evaluate the effects of SDP exposure on unionid mussel survival.

  11. Diversity and functional analysis of LuxR-type transcriptional regulators of cyclic lipopeptide biosynthesis in Pseudomonas fluorescens

    NARCIS (Netherlands)

    Bruijn, de I.; Raaijmakers, J.M.

    2009-01-01

    Cyclic lipopeptides (CLPs) are produced by many Pseudomonas species and have several biological functions, including a role in surface motility, biofilm formation, virulence, and antimicrobial activity. This study focused on the diversity and role of LuxR-type transcriptional regulators in CLP

  12. Opening Study on the Development of a New Biosensor for Metal Toxicity Based on Pseudomonas fluorescens Pyoverdine

    Directory of Open Access Journals (Sweden)

    Alessandro Chiadò

    2013-12-01

    Full Text Available To date, different kinds of biosensing elements have been used effectively for environmental monitoring. Microbial cells seem to be well-suited for this task: they are cheap, adaptable to variable field conditions and give a measurable response to a broad number of chemicals. Among different pollutants, heavy metals are still a major problem for the environment. A reasonable starting point for the selection of a biorecognition element to develop a biosensor for metals could be that of a microorganism that exhibits good mechanisms to cope with metals. Pseudomonads are characterized by the secretion of siderophores (e.g., pyoverdine, low-molecular weight compounds that chelate Fe3+ during iron starvation. Pyoverdine is easily detected by colorimetric assay, and it is suitable for simple online measurements. In this work, in order to evaluate pyoverdine as a biorecognition element for metal detection, the influence of metal ions (Fe3+, Cu2+, Zn2+, but also of temperature, pH and nutrients, on microbial growth and pyoverdine regulation has been studied in P. fluorescens. Each of these variables has been shown to influence the synthesis of siderophore: for instance, the lower the temperature, the higher the production of pyoverdine. Moreover, the concentration of pyoverdine produced in the presence of metals has been compared with the maximum allowable concentrations indicated in international regulations (e.g., 98/83/EC, and a correlation that could be useful to build a colorimetric biosensor has been observed.

  13. The oxyanion hole of Pseudomonas fluorescens mannitol 2-dehydrogenase: a novel structural motif for electrostatic stabilization in alcohol dehydrogenase active sites.

    Science.gov (United States)

    Klimacek, Mario; Nidetzky, Bernd

    2009-12-23

    The side chains of Asn191 and Asn300 constitute a characteristic structural motif of the active site of Pseudomonas fluorescens mannitol 2-dehydrogenase that lacks precedent in known alcohol dehydrogenases and resembles the canonical oxyanion binding pocket of serine proteases. We have used steady-state and transient kinetic studies of the effects of varied pH and deuterium isotopic substitutions in substrates and solvent on the enzymatic rates to delineate catalytic consequences resulting from individual and combined replacements of the two asparagine residues by alanine. The rate constants for the overall hydride transfer to and from C-2 of mannitol, which were estimated as approximately 5 x 102 s-1 and approximately 1.5 x 103 s-1 in the wild-type enzyme respectively, were selectively slowed, between 540- and 2700-fold, in single-site mannitol 2-dehydrogenase mutants. These effects were additive in the corresponding doubly mutated enzyme, suggesting independent functioning of the two asparagine residues in catalysis. Partial disruption of the oxyanion hole in single-site mutants caused an upshift, by >or=1.2 pH units, in the kinetic pK of the catalytic acid-base Lys295 in the enzyme-NAD+-mannitol complex. The oxyanion hole of mannitol 2-dehydrogenase is suggested to drive a precatalytic conformational equilibrium at the ternary complex level in which the reactive group of the substrate is 'activated' for chemical conversion through its precise alignment with the unprotonated side chain of Lys295 (mannitol oxidation) and C=O bond polarization by the carboxamide moieties of Asn191 and Asn300 (fructose reduction). In the subsequent hydride transfer step, the two asparagine residues provide approximately 40 kJ/mol of electrostatic stabilization.

  14. Improvement of a dry formulation of Pseudomonas fluorescens EPS62e for fire blight disease biocontrol by combination of culture osmoadaptation with a freeze-drying lyoprotectant.

    Science.gov (United States)

    Cabrefiga, J; Francés, J; Montesinos, E; Bonaterra, A

    2014-10-01

    To study the effect of lyoprotectants and osmoadaptation on viability of Pseudomonas fluorescens EPS62e during freeze-drying and storage and to evaluate the formulation in terms of efficacy in biocontrol and fitness on pear flowers. A wettable powder formulation of a biocontrol agent of fire blight was optimized by means of lyoprotectants and culture osmoadaptation. Freeze-drying was used to obtain dehydrated cells, and the best viability (70% of survival) was obtained using lactose as lyoprotectant. Survival during lyophilization was additionally improved using physiological adaptation of cells during cultivation under salt-amended medium (osmoadaptation). The procedure increased the survival of cells after freeze-drying attaining viability values close to a 100% in the lactose-formulated product (3 × 10(11) CFU g(-1) ), and through the storage period of 1 year at 4°C. The dry formulation showed also an improved biocontrol efficacy and survival of EPS62e on pear flowers under low relative humidity conditions. Cell viability after freeze-drying was improved using lactose as lyoprotectant combined with a procedure of osmoadaptation during cultivation. The powder-formulated product remained active for 12 months and retained biocontrol levels similar to that of fresh cells. The formulation showed an improved survival of EPS62e on flowers and an increase of the efficacy of biocontrol of fire blight at low relative humidity. The results have a potential value for commercial application in biocontrol agents not only of fire blight but also of other plant diseases. © 2014 The Society for Applied Microbiology.

  15. Control biológico del marchitamiento vascular causado por fusarium oxysporum f. sp. phaseoli en fríjol phaseolus vulgaris l., mediante la acción combinada de entrophospora colombiana, trichoderma sp. y pseudomonas fluorescens

    OpenAIRE

    Avendaño, Camila; Arbeláez, Germán; Rondón, Guillermo

    2010-01-01

    Entrophospora colombiana, Trichoderma sp., Pseudomonas fluorescens y una combinación de estos antagonistas fueron evaluados como biocontroladores de Fusarium oxysporumf. sp. Phaseoli en plantas de fríjol de la variedad ‘ICA Tundama’. El ensayo se estableció en una casa de malla del Programa nacional de manejo integrado de plagas (MIP) de la Corporación Colombiana de Investigación Agropecuaria (Corpoica), en el Centro de Investigación Tibaitatá, Mosquera (Cundinamarca), utilizando un diseño co...

  16. Nitrogen availability to Pseudomonas fluorescens DF57 is limited during decomposition of barley straw in bulk soil and in the barley rhizosphere.

    Science.gov (United States)

    Jensen, L E; Nybroe, O

    1999-10-01

    The availability of nitrogen to Pseudomonas fluorescens DF57 during straw degradation in bulk soil and in barley rhizosphere was studied by introducing a bioluminescent reporter strain (DF57-N3), responding to nitrogen limitation, to model systems of varying complexity. DF57-N3 was apparently not nitrogen limited in the natural and sterilized bulk soil used for these experiments. The soil was subsequently amended with barley straw, representing a plant residue with a high carbon-to-nitrogen ratio (between 60 and 100). In these systems the DF57-N3 population gradually developed a nitrogen limitation response during the first week of straw decomposition, but exclusively in the presence of the indigenous microbial population. This probably reflects the restricted ability of DF57 to degrade plant polymers by hydrolytic enzymes. The impact of the indigenous population on nitrogen availability to DF57-N3 was mimicked by the cellulolytic organism Trichoderma harzianum Rifai strain T3 when coinoculated with DF57-N3 in sterilized, straw-amended soil. Limitation occurred concomitantly with fungal cellulase production, pointing to the significance of hydrolytic activity for the mobilization of straw carbon sources, thereby increasing the nitrogen demand. Enhanced survival of DF57-N3 in natural soil after straw amendment further indicated that DF57 was cross-fed with carbon/energy sources. The natural barley rhizosphere was experienced by DF57-N3 as an environment with restricted nitrogen availability regardless of straw amendment. In the rhizosphere of plants grown in sterilized soil, nitrogen limitation was less severe, pointing to competition with indigenous microorganisms as an important determinant of the nitrogen status for DF57-N3 in this environment. Hence, these studies have demonstrated that nitrogen availability and gene expression in Pseudomonas is intimately linked to the structure and function of the microbial community. Further, it was demonstrated that the

  17. Salicylic acid degradation from aqueous solutions using Pseudomonas fluorescens HK44: parameters studies and application tools Degradação de ácido salicílico presente em soluções sintéticas utilizando Pseudomonas fluorescens HK44

    Directory of Open Access Journals (Sweden)

    Tatyane R. Silva

    2007-03-01

    Full Text Available The optimal conditions for salicylic acid biodegradation by Pseudomonas fluorescens HK44 were determined in this study with the intention to create a microbial sensor. Kinetic experiments permitted a definition of 60 and 30min the time needed to achieve the maximum degradation of salicylic acid presented in a medium with and without yeast extract, respectively. The degradation in medium without yeast extract and the quantification by spectrophotometry 230 nm were selected to be used in further tests. The use of preactivated cells or on the exponential growth phase showed better salicylic acid degradation percentages when compared to nonactivated cells or on the stationary growth state. Finally, the best cellular concentration used on the salicylic acid degradation was 0,1 g.L-1. Strain HK44 shows to be capable of degrade salicylic acid presented in simple aqueous systems, making this strain a promising tool for the application on a luminescent microbial sensor.Com a intenção de criar um sensor microbiano, as condições ótimas para a biodegradação de ácido salicílico por Pseudomonas fluorescens HK44 foram determinadas neste estudo. Os experimentos cinéticos permitiram a definição dos tempos de 60 e 30 minutos como necessários para atingir a máxima degradação de ácido salicílico presente em meio com ou sem extrato de lêvedo, respectivamente. A degradação no meio sem extrato de lêvedo e a quantificação através de espectrofotometria 230 nm foram selecionadas para serem utilizadas em testes posteriores. O uso de células pré-ativadas ou na fase exponencial de crescimento apresentou melhores porcentagens de degradação de ácido salicílico quando comparadas a células não-ativadas ou no estado estacionário de crescimento. Além disso, a melhor concentração celular utilizada nessa degradação foi 0,1 g.L¹. A cepa HK44 parece ser capaz de degradar o ácido salicílico presente em sistemas aquosos simples, tornando este

  18. A propensity score-matched analysis of the impact of minimum inhibitory concentration on mortality in patients with Pseudomonas aeruginosa bacteremia treated with cefepime or ceftazidime.

    Science.gov (United States)

    Ratliff, Angharad R; Gentry, Chris A; Williams, Riley J

    2017-04-01

    The United States Clinical and Laboratory Standards Institute recently elected not to revise ceftazidime and cefepime Pseudomonas aeruginosa minimum inhibitory concentration (MIC) susceptibility breakpoints but rather recommended specific dosage regimens to correspond to breakpoints. This study's objective was to examine mortality of low and high MIC P. aeruginosa isolates in bacteremic patients treated with cefepime or ceftazidime. Data were gathered through a Veterans Health Administration national administrative database for veterans with P. aeruginosa blood cultures who received cefepime or ceftazidime. Seventy-four patients in the low MIC (≤2 μg/mL) group and 29 patients in the high (4-8 μg/mL) MIC group were included. Independent baseline variables associated with 30-day all-cause mortality were determined through multivariate analysis to calculate propensity scores and perform matching. All-cause 30-day mortality was not statistically significant between the 2 resultant propensity score-matched groups (17.2% mortality in the low MIC group versus 27.6% in the high MIC group; P=0.34). Data suggested that P. aeruginosa bacteremia episodes where the cephalosporin MIC = 8 μg/mL may have higher mortality, however this may be reflective of higher propensity scores. Our study suggests that it is reasonable to designate a cefepime or ceftazidime MIC ≤8 μg/mL as susceptible for P. aeruginosa bacteremia infections, but potential suboptimal outcomes in episodes for which the P. aeruginosa MIC is 8 μg/mL may need further investigation. Published by Elsevier Inc.

  19. Annual changes in bioactive contents and production in field-grown blackberry after inoculation with Pseudomonas fluorescens.

    Science.gov (United States)

    Ramos-Solano, B; Garcia-Villaraco, A; Gutierrez-Mañero, F J; Lucas, J A; Bonilla, A; Garcia-Seco, D

    2014-01-01

    The aim of this study was two-fold: first, to characterize blackberry fruits from Rubus sp. var. Lochness along the year, and secondly, to evaluate the ability of a Pseudomonas strain (N21.4) to improve fruit yield and quality under field conditions in production greenhouses throughout the year. The strain was root or leaf inoculated to blackberry plants and fruits were harvested in each season. Nutritional parameters, antioxidant potential and bioactive contents were determined; total fruit yield was recorded. Blackberries grown under short day conditions (autumn and winter) showed significantly lower °Brix values than fruits grown under long day conditions. Interestingly, an increase in fruit °Brix, relevant for quality, was detected after bacterial challenge, together with significant and sustained increases in total phenolics and flavonoids. Improvements in inoculated fruits were more evident from October through early March, when environmental conditions are worse. In summary, N21.4 is an effective agent to increase fruit quality and production along the year in blackberry; this is an environmentally friendly approach to increase fruit quality. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  20. INFLUENCIA DE LA BACTERIA Pseudomonas fluorescens EN LA LECHE, SOBRE LAS CARACTERÍSTICAS SENSORIALES DEL QUESO DOBLE CREMA

    Directory of Open Access Journals (Sweden)

    SJ González

    2007-01-01

    Full Text Available El objetivo de este trabajo fue observar el efecto de la presencia de microorganismos psicro-tróÀcos en la leche, sobre las características sensoriales del queso doble crema. Para esto, se inoculó la leche con un cultivo de Pseudomonas Áuorescens, a un nivel de 108 unidades formadoras de colonia por mililitro (ufc/ml. La leche se refrigeró a 4 ºC por seis días, se pasteurizó y posteriormente se preparó el queso. Se elaboraron lotes de queso cada 10 días, con el Àn de obtener siete tiempos experimentales. A cada uno se le determinó la vida útil sensorial. Los resultados de las pruebas sensoriales se analizaron con el programa S-PLUS de estadísti-ca de supervivencia aplicada a la vida útil sensorial de alimentos. Se determinó que el tiempo de vida útil sensorial del queso doble crema elaborado con leche en estas condiciones, y alma-cenado a 4 °C, está alrededor de 30 días, disminuyendo en un 50% con relación al patrón.

  1. Zinc Improves Biocontrol of Fusarium Crown and Root Rot of Tomato by Pseudomonas fluorescens and Represses the Production of Pathogen Metabolites Inhibitory to Bacterial Antibiotic Biosynthesis.

    Science.gov (United States)

    Duffy, B K; Défago, G

    1997-12-01

    ABSTRACT Crown and root rot of tomato caused by Fusarium oxysporum f. sp. radicis-lycopersici is an increasing problem in Europe, Israel, Japan, and North America. The biocontrol agent Pseudomonas fluorescens strain CHA0 provides only moderate control of this disease. A one-time amendment of zinc EDTA at 33 mug of Zn(2+)/ml to hydroponic nutrient solution in soilless rockwool culture did not reduce disease when used alone, but did reduce disease by 25% in the presence of CHA0. In in vitro studies with the pathogen, zinc at concentrations as low as 10 mug/ml abolished production of the phytotoxin fusaric acid, a Fusarium pathogenicity factor, and increased production of microconidia over 100-fold, but reduced total biomass. Copper EDTA at 33 mug of Cu(2+)/ml had a similar effect as zinc on the pathogen in vitro; it reduced disease when used alone, and increased the biocontrol activity of CHA0 in soilless culture. Ammonium-molybdate neither improved the biocontrol activity of CHA0 nor affected production of fusaric acid or microconidia. Strain CHA0 did not degrade fusaric acid. Fusaric acid at concentrations as low as 0.12 mug/ml repressed production by CHA0 of the antibiotic 2,4-diacetylphloroglucinol, a key factor in the biocontrol activity of this strain. Production of pyoluteorin by CHA0 was also reduced, but production of hydrogen cyanide and protease was not affected, suggesting that fusaric acid affects biosynthesis at a regulatory level downstream of gacA and apdA genes. Fusaric acid did not affect the recovery of preformed antibiotics nor did it affect bacterial growth even at concentrations as high as 200 mug/ml. When microbial meta-bolite production was measured in the rockwool bioassay, zinc amendments reduced fusaric acid production and enhanced 2,4-diacetylphloro-glucinol production. We suggest that zinc, which did not alleviate the repression of antibiotic biosynthesis by fusaric acid, improved biocontrol activity by reducing fusaric acid production by

  2. Efficacy of spray –Dried Pseudomonas fluorescens, strain CL145A (Zequanox®), for controlling Zebra Mussels (Dreissena polymorpha) within Lake Minnetonka, MN enclosures

    Science.gov (United States)

    Luoma, James A.; Severson, Todd J.

    2016-01-01

    The efficacy of whole water column and subsurface applications of the biopesticide Zequanox®, a commercially prepared spray-dried powder formulation of Pseudomonas fluorescens (strain CL145A), were evaluated for controlling zebra mussels (Dreissena polymorpha) within 27-m2 enclosures in Lake Minnetonka (Deephaven, Minnesota). Five treatments consisting of (1) two whole water column Zequanox applications, (2) two subsurface Zequanox applications, and (3) an untreated control were completed on each of three independent treatment days during September 2014. The two types of samplers used in the study were (1) type 1 samplers, which were custom built multi-plate samplers (wood, perforated aluminum, and tile substrates) that were placed into Robinson’s Bay in June of 2013 to allow for natural colonization by zebra mussels, and (2) type 2 samplers, which consisted of zebra mussels adhering to perforated aluminum trays that were placed into mesh containment bags. One day prior to treatment, three individual samplers of each type were distributed to test enclosures and exposed to a randomly assigned treatment. Sampling to determine the zebra mussel biomass adhering to type 1 samplers and the survival assessments for zebra mussels contained in type 2 samplers were completed ~40 days after exposure. The zebra mussel biomass adhering to type 1 samplers and the survival of zebra mussels contained in type 2 samplers were significantly less in groups treated with the highest Zequanox concentrations and in groups that received whole water column applications than comparable groups treated with lower Zequanox concentrations and subsurface applications. However, standardization of biomass and survival results to the amount of Zequanox applied showed that the lower concentrations and subsurface applications were more cost efficient, with respect to product used, at reducing zebra mussel biomass and for inducing zebra mussel mortality. Although the subsurface application methods

  3. The interplay of StyR and IHF regulates substrate-dependent induction and carbon catabolite repression of styrene catabolism genes in Pseudomonas fluorescens ST

    Directory of Open Access Journals (Sweden)

    Leoni Livia

    2008-06-01

    Full Text Available Abstract Background In Pseudomonas fluorescens ST, the promoter of the styrene catabolic operon, PstyA, is induced by styrene and is subject to catabolite repression. PstyA regulation relies on the StyS/StyR two-component system and on the IHF global regulator. The phosphorylated response regulator StyR (StyR-P activates PstyA in inducing conditions when it binds to the high-affinity site STY2, located about -40 bp from the transcription start point. A cis-acting element upstream of STY2, named URE, contains a low-affinity StyR-P binding site (STY1, overlapping the IHF binding site. Deletion of the URE led to a decrease of promoter activity in inducing conditions and to a partial release of catabolite repression. This study was undertaken to assess the relative role played by IHF and StyR-P on the URE, and to clarify if PstyA catabolite repression could rely on the interplay of these regulators. Results StyR-P and IHF compete for binding to the URE region. PstyA full activity in inducing conditions is achieved when StyR-P and IHF bind to site STY2 and to the URE, respectively. Under catabolite repression conditions, StyR-P binds the STY1 site, replacing IHF at the URE region. StyR-P bound to both STY1 and STY2 sites oligomerizes, likely promoting the formation of a DNA loop that closes the promoter in a repressed conformation. We found that StyR and IHF protein levels did not change in catabolite repression conditions, implying that PstyA repression is achieved through an increase in the StyR-P/StyR ratio. Conclusion We propose a model according to which the activity of the PstyA promoter is determined by conformational changes. An open conformation is operative in inducing conditions when StyR-P is bound to STY2 site and IHF to the URE. Under catabolite repression conditions StyR-P cellular levels would increase, displacing IHF from the URE and closing the promoter in a repressed conformation. The balance between the open and the closed

  4. Effects of the tomato pathogen Fusarium oxysporum f. sp. radicis-lycopersici and of the biocontrol bacterium Pseudomonas fluorescens WCS365 on the composition of organic acids and sugars in tomato root exudate.

    Science.gov (United States)

    Kamilova, Faina; Kravchenko, Lev V; Shaposhnikov, Alexander I; Makarova, Nataliya; Lugtenberg, Ben

    2006-10-01

    The effects of the pathogenic fungus Fusarium oxysporum f. sp. radicis-lycopersici and of the bacterial biocontrol strain Pseudomonas fluorescens WCS365, and of both microbes, on the amounts and composition of root exudate components of tomato plants grown in a gnotobiotic stonewool substrate system were studied. Conditions were selected under which introduction of F. oxysporum f. sp. radicis-lycopersici caused severe foot and root rot, whereas inoculation of the seed with P. fluorescens WCS365 decreased the percentage of diseased plants from 96 to 7%. This is a much better disease control level than was observed in potting soil. Analysis of root exudate revealed that the presence of F. oxysporum f. sp. radicis-lycopersici did not alter the total amount of organic acids, but that the amount of citric acid decreased and that of succinic acid increased compared with the nontreated control. In contrast, in the presence of the P. fluorescens biocontrol strain WCS365, the total amount of organic acid increased, mainly due to a strong increase of the amount of citric acid, whereas the amount of succinic acid decreased dramatically. Under biocontrol conditions, when both microbes are present, the content of succinic acid decreased and the level of citric acid was similar to that in the nontreated control. The amount of sugar was approximately half that of the control sample when either one of the microbes was present alone or when both were present. Analysis of the interactions between the two microbes grown together in sterile tomato root exudate showed that WCS365 inhibited multiplication of F. oxysporum f. sp. radicis-lycopersici, whereas the fungus did not affect the number of CFU of the bacterium.

  5. Nunamycin and Nunapeptin: Two novel cyclic peptides are key components of the antimicrobial activity of the Greenlandic isolate Pseudomonas fluorescens In5

    DEFF Research Database (Denmark)

    Hennessy, Rosanna Catherine; Phippen, Christopher; Nielsen, Kristian F.

    suppressive soil, P. fluorescens In5 is therefore a promising potential biocontrol agent with potent activity against plant pathogens. Studies to date have shown nunamycin and nunapeptin as key compounds underpinning this antimicrobial activity. A combination of molecular genetic strain manipulations and omic...

  6. Characterization of the CrbS/R Two-Component System in Pseudomonas fluorescens Reveals a New Set of Genes under Its Control and a DNA Motif Required for CrbR-Mediated Transcriptional Activation

    Directory of Open Access Journals (Sweden)

    Edgardo Sepulveda

    2017-11-01

    Full Text Available The CrbS/R system is a two-component signal transduction system that regulates acetate utilization in Vibrio cholerae, P. aeruginosa, and P. entomophila. CrbS is a hybrid histidine kinase that belongs to a recently identified family, in which the signaling domain is fused to an SLC5 solute symporter domain through aSTAC domain. Upon activation by CrbS, CrbR activates transcription of the acs gene, which encodes an acetyl-CoA synthase (ACS, and the actP gene, which encodes an acetate/solute symporter. In this work, we characterized the CrbS/R system in Pseudomonas fluorescens SBW25. Through the quantitative proteome analysis of different mutants, we were able to identify a new set of genes under its control, which play an important role during growth on acetate. These results led us to the identification of a conserved DNA motif in the putative promoter region of acetate-utilization genes in the Gammaproteobacteria that is essential for the CrbR-mediated transcriptional activation of genes under acetate-utilizing conditions. Finally, we took advantage of the existence of a second SLC5-containing two-component signal transduction system in P. fluorescens, CbrA/B, to demonstrate that the activation of the response regulator by the histidine kinase is not dependent on substrate transport through the SLC5 domain.

  7. Carvacrol and 1,8-cineole alone or in combination at sublethal concentrations induce changes in the cell morphology and membrane permeability of Pseudomonas fluorescens in a vegetable-based broth.

    Science.gov (United States)

    de Sousa, Jossana Pereira; Torres, Rayanne de Araújo; de Azerêdo, Geíza Alves; Figueiredo, Regina Célia Bressan Queiroz; Vasconcelos, Margarida Angélica da Silva; de Souza, Evandro Leite

    2012-08-01

    This study aimed to investigate the effects of sublethal concentrations of carvacrol (CAR) and 1,8-cineole (CIN) alone and in combination on the morphology, cell viability and membrane permeability of Pseudomonas fluorescens ATCC 11253 cultivated in a vegetable-based broth. Transmission and scanning electron microscopy images of bacterial cells exposed to CAR and CIN alone or in combination showed marked ultrastructural changes after 1h of exposure. These changes included shrunken protoplasm, discontinuity of the outer and cytoplasmic membranes and leakage of the intracellular material. Confocal scanning laser microscopy images corroborated the electron microscopy data, showing a decrease in the number of SYTO-9 cells (intact cells) with a concomitant increase in the number of PI-positive cells (dead cells). All of these morphological changes are indicative of increased membrane permeability and the loss of bacterial envelope integrity, which ultimately lead to cell death. The combination of sublethal concentrations of CAR and CIN could be applied to inhibit the growth of P. fluorescens on vegetables. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Kinetics of biofilm formation and desiccation survival of Listeria monocytogenes in single and dual species biofilms with Pseudomonas fluorescens, Serratia proteamaculans or Shewanella baltica on food-grade stainless steel surfaces.

    Science.gov (United States)

    Daneshvar Alavi, Hessam Edin; Truelstrup Hansen, Lisbeth

    2013-01-01

    This study investigated the dynamics of static biofilm formation (100% RH, 15 °C, 48-72 h) and desiccation survival (43% RH, 15 °C, 21 days) of Listeria monocytogenes, in dual species biofilms with the common spoilage bacteria, Pseudomonas fluorescens, Serratia proteamaculans and Shewanella baltica, on the surface of food grade stainless steel. The Gram-negative bacteria reduced the maximum biofilm population of L. monocytogenes in dual species biofilms and increased its inactivation during desiccation. However, due to the higher desiccation resistance of Listeria relative to P. fluorescens and S. baltica, the pathogen survived in greater final numbers. In contrast, S. proteamaculans outcompeted the pathogen during the biofilm formation and exhibited similar desiccation survival, causing the N21 days of Serratia to be ca 3 Log10(CFU cm(-2)) greater than that of Listeria in the dual species biofilm. Microscopy revealed biofilm morphologies with variable amounts of exopolymeric substance and the presence of separate microcolonies. Under these simulated food plant conditions, the fate of L. monocytogenes during formation of mixed biofilms and desiccation depended on the implicit characteristics of the co-cultured bacterium.

  9. INOCULACIÓN AL SUELO CON Pseudomonas fluorescens, Azospirillum oryzae, Bacillus subtilis Y MICROORGANISMOS DE MONTAÑA (MM Y SU EFECTO SOBRE UN SISTEMA DE ROTACIÓN SOYA-TOMATE BAJO CONDICIONES DE INVERNADERO

    Directory of Open Access Journals (Sweden)

    Leida Castro Barquero

    2015-01-01

    Full Text Available Se evaluó un sistema de rotación soya- tomate, con incorporación de biomasa verde y aplicación de inóculos microbianos individuales y en mezcla sobre el crecimiento de las plantas y propiedades edáficas; para ello se evaluaron en invernadero por 24 meses los siguientes 9 trata - mientos: solo tomate (T; rotación tomate-soya (TS; rotación tomate-soya con inoculaciones individuales de Azospirillum oryzae (A; de Pseudomonas fluorescens (P; de Bacillus sub - tilis (B; de microorganismos de montaña (MM; y las inoculaciones en mezcla de B. subtilis y P. fluorescens (BP; de B. subtilis, P. fluorescens y A. oryzae ( BPA; d e B. subtilis , P. fluorescens , Azospirillum sp. y MM (BPAMM. Se evalua - ron las variables físicas: densidad aparente y de partículas; conductividad hidráulica; poros totales; estabilidad de agregados; resistencia a la penetración (RP; las variables químicas: pH; conductividad eléctrica; contenido de N y C; relación C/N; contenido de nutrientes en suelos y foliares; las variables biológicas: respiración de suelos, unidades formadoras de colonias de hongos, bacterias y actinomicetos y el peso fres - co y seco foliar. Las variables físicas no fueron afectadas por los tratamientos, con excepción de RP, que fue mayor en el tratamiento T. Las varia - bles biológicas y químicas fueron sensibles a los tratamientos, con valores significativamente más altos en presencia de MM. Destaca el incremento del P en solución de suelo en tratamientos a los que se adicionó MM: pasó de 6 a 20 mg.l -1 ; esta condición se reflejó además en la cantidad de P en el tejido foliar al final del ensayo. Se determi - nó que el pH, CE y la respiración del suelo fueron afectados por la interacción entre los tratamientos aplicados y el tiempo transcurrido; los mayores valores se obtuvieron al final del ensayo y en los tratamientos con MM.

  10. Inoculación al suelo con Pseudomonas fluorescens, Azospirillum oryzae, Bacillus subtilis y microorganismos de montaña (mm y su efecto sobre un sistema de rotación soya-tomate bajo condiciones de invernadero

    Directory of Open Access Journals (Sweden)

    Leida Castro Barquero

    2015-11-01

    Full Text Available Se evaluó un sistema de rotación soyatomate, con incorporación de biomasa verde y aplicación de inóculos microbianos individuales y en mezcla sobre el crecimiento de las plantas y propiedades edáficas; para ello se evaluaron en invernadero por 24 meses los siguientes 9 tratamientos: solo tomate (T; rotación tomate-soya (TS; rotación tomate-soya con inoculaciones individuales de Azospirillum oryzae (A; de Pseudomonas fluorescens (P; de Bacillus subtilis (B; de microorganismos de montaña (MM; y las inoculaciones en mezcla de B. subtilis y P. fluorescens (BP; de B. subtilis, P. fluorescens y A. oryzae (BPA; de B. subtilis, P. fluorescens, Azospirillum sp. y MM (BPAMM. Se evaluaron las variables físicas: densidad aparente y de partículas; conductividad hidráulica; poros totales; estabilidad de agregados; resistencia a la penetración (RP; las variables químicas: pH; conductividad eléctrica; contenido de N y C; relación C/N; contenido de nutrientes en suelos y foliares; las variables biológicas: respiración de suelos, unidades formadoras de colonias de hongos, bacterias y actinomicetos y el peso fresco y seco foliar. Las variables físicas no fueron afectadas por los tratamientos, con excepción de RP, que fue mayor en el tratamiento T. Las variables biológicas y químicas fueron sensibles a los tratamientos, con valores significativamente más altos en presencia de MM. Destaca el incremento del P en solución de suelo en tratamientos a los que se adicionó MM: pasó de 6 a 20 mg.l-1; esta condición se reflejó además en la cantidad de P en el tejido foliar al final del ensayo. Se determinó que el pH, CE y la respiración del suelo fueron afectados por la interacción entre los tratamientos aplicados y el tiempo transcurrido; los mayores valores se obtuvieron al final del ensayo y en los tratamientos con MM.

  11. Control of Fusarium verticillioides, cause of ear rot of maize, by Pseudomonas fluorescens

    DEFF Research Database (Denmark)

    Nayaka, Siddaiah Chandra; Shankar, Akarere C. Udaya; Reddy, Munagala S.

    2009-01-01

    Abstract BACKGROUND: Maize is one of the staple food crops grown in India. Fusarium verticillioides (Sacc.) Nirenberg is the most important fungal pathogen of maize, associated with diseases such as ear rot and kernel rot. Apart from the disease, it is capable of producing fumonisins, which have...... and the formulations, in comparison with the control, increased plant growth and vigour as measured by seed germination, seedling vigour, plant height, 1000 seed weight and yield. P. fluorescens pure culture used as seed treatment and as spray treatment enhanced the growth parameters and reduced the incidence of F....... verticillioides and the level of fumonisins to a maximum extent compared with the other treatments. CONCLUSION: The study demonstrates the potential role of P. fluorescens and its formulations in ear rot disease management. The biocontrol potential of this isolate is more suited for fumonisin reduction in maize...

  12. In vitro inoculation of Aeromonas hydrophila and Pseudomonas fluorescens in cryopreserved silver barb (Barbodes gonionotus) milt: Effect on fertilization capacity and transmission potential to embryos.

    Science.gov (United States)

    Boonthai, Traimat; Khaopong, Weerasith; Sangsong, Jumlong; Vuthiphandchai, Verapong; Nimrat, Subuntith

    2017-11-16

    Purposive use of cryopreserved sperm contaminated with pathogenic agents has increased the risk of spreading of fish diseases. The objective of this study was to investigate the effects of A. hydrophila subsp. hydrophila and P. fluorescens inoculations into cryostored milt on fertilization capacity and transmission potential to embryos of silver barb (Barbodes gonionotus) with or without 0.25% penicillin-streptomycin (PS) administration. The experiment comprised six treatments: addition of milt into T1) extender only, T2) extender with 0.25% PS, T3) extender with A. hydrophila subsp. hydrophila (BG19), T4) extender with A. hydrophila subsp. hydrophila (BG19) and 0.25% PS, T5) extender with P. fluorescens (BG20) and T6) extender with P. fluorescens (BG20) and 0.25% PS. Milt were loaded into 0.25-mL straws and cryostored in the controlled-rate programmable freezer. After a cryostorage for 28 d, post-thawed sperm were evaluated for the fertilization capacity and risk of pathogen transmission to embryos. Inoculation of A. hydrophila subsp. hydrophila and P. fluorescens into extended milt (T3 and T5) caused a reduction (P fertilization capacity of cryopreserved sperm. Cryopreserved sperm inoculated with the two pathogenic bacteria and 0.25% PS (T4 and T6) did not fertilize the eggs. The two pathogenic bacteria could be transmitted into embryos after artificial insemination of eggs with bacterial-inoculated cryopreserved sperm, suggesting that the risks of disease transmission via cryopreserved fish sperm would exist. This is the first study reporting pathogenic bacterial transmission on in vitro fish embryos through artificial insemination of cryopreserved sperm. Copyright © 2017. Published by Elsevier Inc.

  13. Evaluation of gamma irradiation effect and Pseudomonas ...

    African Journals Online (AJOL)

    Antagonistic effect of Pseudomonas fluorescens and influence of gamma irradiation on the development of Penicillium expansum, the causal agent of postharvest disease on apple fruit was studied. P. fluorescens was originally isolated from rhizosphere of the apple trees. Suspension of P. fluorescens and P. expansum ...

  14. Efficiency of the formulated plant-growth promoting Pseudomonas fluorescens MC46 inoculant on triclocarban treatment in soil and its effect on Vigna radiata growth and soil enzyme activities.

    Science.gov (United States)

    Sipahutar, Merry Krisdawati; Piapukiew, Jittra; Vangnai, Alisa S

    2018-02-15

    For bioaugmentation-based treatment of triclocarban (TCC), an emerging soil pollutant that is recalcitrant to biodegradation and phytotransformation, efficient TCC-degrading bacteria with an effective soil-delivering means are required. This work developed the formulated bacterial inoculant, and successfully demonstrated its TCC removal and detoxification performance in pot soil experiment with Vigna radiata plants. The soil bacterium Pseudomonas fluorescens MC46 was isolated as TCC-degrading, plant-growth promoting bacterium. The characterizations were conducted in vitro revealing that it could utilize TCC as a sole carbon source, and at a wide and higher concentration range from 1.6-31.6mgkg -1 than those previously reported, while the detoxification was assessed by cytogenotoxicity and phytotoxicity tests. The developed sawdust-based inoculant formula combined with molasses (5% w/w), and either PEG or CMC-starch blend (1% w/w) could maintain a 20-week shelf-life inoculant stability in terms of cell viability, and TCC-degrading activity. Bioaugmentation of the formulated inoculants into TCC-contaminated soil efficiently removed TCC up to 74-76% of the initial concentration, mitigated toxicity, restored plant growth and health, and enhanced soil enzyme activities. This work is the first to demonstrate potential application of the formulated plant-growth promoting bacterial inoculant for the treatment and detoxification of a persistent TCC contaminated in soil. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Alkaline lipase from Pseudomonas fluorescens non-covalently immobilised on pristine versus oxidised multi-wall carbon nanotubes as efficient and recyclable catalytic systems in the synthesis of Solketal esters.

    Science.gov (United States)

    Boncel, Sławomir; Zniszczoł, Aurelia; Szymańska, Katarzyna; Mrowiec-Białoń, Julita; Jarzębski, Andrzej; Walczak, Krzysztof Z

    2013-09-10

    In order to produce effective and recyclable catalysts for enantioselective transesterification in the industrial applications, alkaline lipase from Pseudomonas fluorescens was non-covalently immobilised (ca. 6 wt%) on pristine multi-wall carbon nanotubes (MWCNTs) and oxidised MWCNTs (O-MWCNTs) using an adsorption technique. Mesoporous silica modified with n-octyl groups was used as a reference support. Irreversible transesterifications of three vinyl esters (acyl donors) by racemic Solketal with a chromatographically (GC) traced kinetics were selected as model reactions. The undertaken comparative studies revealed that different morphology and chemical functionalisation of the supports led to various enzyme loadings, catalytic activities and enantioselectivities. MWCNT-lipase emerged as the exceptionally active (yield up to 98%, t=1h, 1320 Ug(-1), i.e. 9 times more active than native enzyme) whereas lipase immobilised on O-MWCNTs as the most enantioselective system, particularly for longer acyl chain esters (e.e. up to 72% after 30 min at yield of 20%, 340 Ug(-1)). Moreover, the activity of all nanotube-based catalysts after 10 cycles of transesterification remained practically unchanged. The differences in performance of MWCNTs and O-MWCNTs as solid supports were found to be based on geometry of pores, dominating hydrophobic interactions and absence/presence of the surface polar groups. Due to an excellent activity and reusability of the nanotube-lipase catalysts one can propose (O-)MWCNT as supports of a prospective industrial relevance. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. The incidence and prognosis of patients with bacteremia

    DEFF Research Database (Denmark)

    Nielsen, Stig Lønberg

    2015-01-01

    of community-acquired bacteremia (3.7% per year, p Staphylococcus...... aureus, co-agulasenegative staphylococci and Streptococcus pneumoniae, and increased for Pseudomonas aeruginosa and enterococci species (p

  17. Complex regulation of AprA metalloprotease in Pseudomonas fluorescens M114: evidence for the involvement of iron, the ECF sigma factor, PbrA and pseudobactin M114 siderophore.

    Science.gov (United States)

    Maunsell, Bláithín; Adams, Claire; O'Gara, Fergal

    2006-01-01

    In the soil bacterium Pseudomonas fluorescens M114, extracellular proteolytic activity and fluorescent siderophore (pseudobactin M114) production were previously shown to be co-ordinately negatively regulated in response to environmental iron levels. An iron-starvation extracytoplasmic function sigma factor, PbrA, required for the transcription of siderophore biosynthetic genes, was also implicated in M114 protease regulation. The current study centred on the characterization and genetic regulation of the gene(s) responsible for protease production in M114. A serralysin-type metalloprotease gene, aprA, was identified and found to encode the major, if not only, extracellular protease produced by this strain. The expression of aprA and its protein product were found to be subject to complex regulation. Transcription analysis confirmed that PbrA was required for full aprA transcription under low iron conditions, while the ferric uptake regulator, Fur, was implicated in aprA repression under high iron conditions. Interestingly, the iron regulation of AprA was dependent on culture conditions, with PbrA-independent AprA-mediated proteolytic activity observed on skim milk agar supplemented with yeast extract, when supplied with iron or purified pseudobactin M114. These effects were not observed on skim milk agar without yeast extract. PbrA-independent aprA expression was also observed from a truncated transcriptional fusion when grown in sucrose asparagine tryptone broth supplied with iron or purified pseudobactin M114. Thus, experimental evidence suggested that iron mediated its effects via transcriptional activation by PbrA under low iron conditions, while an as-yet-unidentified sigma factor(s) may be required for the PbrA-independent aprA expression and AprA proteolytic activity induced by siderophore and iron.

  18. High mannose-binding antiviral lectin PFL from Pseudomonas fluorescens Pf0-1 promotes cell death of gastric cancer cell MKN28 via interaction with α2-integrin.

    Directory of Open Access Journals (Sweden)

    Yuichiro Sato

    Full Text Available Novel anti-HIV lectin family which shows a strict binding specificity for high mannose glycans has been found in lower organisms. The bacterial orthologue has been identified in the genome of Pseudomonas fluorescens Pf0-1 and the gene coding a putative lectin was cloned, expressed in Escherichia coli and purified by one step gel filtration. Glycan array screening of the recombinant lectin, termed PFL, has revealed that PFL preferentially recognizes high mannose glycans with α1-3 Man that was highly exposed at the D2 position. In contrast, masking of this α1-3 Man with α1-2 Man dramatically impaired lectin-carbohydrate interactions. Reducing terminal disaccharide, GlcNAc-GlcNAc of high mannose glycans was also essential for PFL-binding. PFL showed a potent anti-influenza virus activity by inhibiting the virus entry into cells at doses of low nanomolar concentration. At micromolar concentration or higher, PFL showed a cytotoxicity accompanying loss of the cell adhesion against human gastric cancer MKN28 cells. The cell surface molecule to which PFL bound was co-precipitated with biotin-labeled PFL and identified as integrin α2 by peptide mass fingerprinting using MALDI-TOF mass spectrometry. Intriguingly, upon treatment with exogenous PFL, integrin α2 on the cell surface underwent rapid internalization to the cytoplasm and accumulated to perinuclear region, together with the bound PFL. The resulting loss of cell adherence would trigger a signaling pathway that induced anoikis-like cell death. These events were effectively inhibited by pretreatment of PFL with mannnan, indicating the involvement of high mannose glycans on PFL-induced cell death that was triggered by PFL-integrin α2 interactions.

  19. Evaluation of economically feasible, natural plant extract-based microbiological media for producing biomass of the dry rot biocontrol strain Pseudomonas fluorescens P22Y05 in liquid culture.

    Science.gov (United States)

    Khalil, Sadia; Ali, Tasneem Adam; Skory, Chris; Slininger, Patricia J; Schisler, David A

    2016-02-01

    The production of microbial biomass in liquid media often represents an indispensable step in the research and development of bacterial and fungal strains. Costs of commercially prepared nutrient media or purified media components, however, can represent a significant hurdle to conducting research in locations where obtaining these products is difficult. A less expensive option for providing components essential to microbial growth in liquid culture is the use of extracts of fresh or dried plant products obtained by using hot water extraction techniques. A total of 13 plant extract-based media were prepared from a variety of plant fruits, pods or seeds of plant species including Allium cepa (red onion bulb), Phaseolus vulgaris (green bean pods), and Lens culinaris (lentil seeds). In shake flask tests, cell production by potato dry rot antagonist Pseudomonas fluorescens P22Y05 in plant extract-based media was generally statistically indistinguishable from that in commercially produced tryptic soy broth and nutrient broth as measured by optical density and colony forming units/ml produced (P ≤ 0.05, Fisher's protected LSD). The efficacy of biomass produced in the best plant extract-based media or commercial media was equivalent in reducing Fusarium dry rot by 50-96% compared to controls. In studies using a high-throughput microbioreactor, logarithmic growth of P22Y05 in plant extract-based media initiated in 3-5 h in most cases but specific growth rate and the time of maximum OD varied as did the maximum pH obtained in media. Nutrient analysis of selected media before and after cell growth indicated that nitrogen in the form of NH4 accumulated in culture supernatants, possibly due to unbalanced growth conditions brought on by a scarcity of simple sugars in the media tested. The potential of plant extract-based media to economically produce biomass of microbes active in reducing plant disease is considerable and deserves further research.

  20. Effectiveness of cleaning and sanitizing procedures in controlling the adherence of Pseudomonas fluorescens, Salmonella Enteritidis, and Staphylococcus aureus to domestic kitchen surfaces Eficiência dos procedimentos de limpeza e de sanitização no controle da adesão de Pseudomonas fluorescens, Salmonella Enteritidis e Staphylococcus aureus em superfícies usadas em cozinhas domésticas

    Directory of Open Access Journals (Sweden)

    Iara Dias Silva

    2010-03-01

    Full Text Available The effectiveness of cleaning and sanitizing procedures in controlling Staphylococcus aureus, Salmonella Enteritidis, and Pseudomonasfluorescens adhered to granite and stainless steel was evaluated. There was no significant difference (p > 0.05 in the adherence of pure cultures of these microorganisms to stainless steel. The numbers of P. fluorescens and S. Enteritidis adhered to granite were greater (p 0.05 between the surfaces. However, a significant difference was observed (p A eficiência dos procedimentos de limpeza e sanitização no controle de Staphylococcus aureus, Salmonella Enteritidis e Pseudomonasfluorescens aderidas em granito e aço inoxidável foi avaliada. Não houve diferença significativa (p > 0,05 na adesão destes microrganismos quando em cultura pura, em aço inoxidável. O número de células aderidas de P. fluorescens e S. Enteritidis foi maior (p 0,05 entre as superfícies. Entretanto, observou-se uma diferença (p < 0,05 entre as soluções sanitizantes utilizadas. Hipoclorito de sódio e ácido peracético apresentaram maior ação bactericida (p < 0,05 que o composto de amônia quaternária. Observou-se que S. aureus apresentou menor resistência à ação desses sanitizantes. Os resultados mostram a importância da adequada realização dos procedimentos de limpeza e sanitização para evitar a adesão bacteriana e formação de biofilme.

  1. Transesterification of Jatropha oil using immobilized Pseudomonas ...

    African Journals Online (AJOL)

    mild transesterification has become of much current interest for alternative fuel production. In the present study the ability of a commercial immobilized Pseudomonas fluorescens MTCC 103 to catalyze the transesterification of Jatropha oil and methanol was investigated. The cell of P. fluorescens was easily immobilized ...

  2. Carbazole-degradative IncP-7 plasmid pCAR1.2 is structurally unstable in Pseudomonas fluorescens Pf0-1, which accumulates catechol, the intermediate of the carbazole degradation pathway.

    Science.gov (United States)

    Takahashi, Yurika; Shintani, Masaki; Li, Li; Yamane, Hisakazu; Nojiri, Hideaki

    2009-06-01

    We determined the effect of the host on the function and structure of the nearly identical IncP-7 carbazole-degradative plasmids pCAR1.1 and pCAR1.2. We constructed Pseudomonas aeruginosa PAO1(pCAR1.2) and P. fluorescens Pf0-1Km(pCAR1.2) and compared their growth on carbazole- and succinate-containing media with that of P. putida KT2440(pCAR1.1). We also assessed the stability of the genetic structures of the plasmids in each of the three hosts. Pf0-1Km(pCAR1.2) showed dramatically delayed growth when carbazole was supplied as the sole carbon source, while the three strains grew at nearly the same rate on succinate. Among the carbazole-grown Pf0-1Km(pCAR1.2) cells, two types of deficient strains appeared and dominated the population; such dominance was not observed in the other two strains or for succinate-grown Pf0-1Km(pCAR1.2). Genetic analysis showed that the two deficient strains possessed pCAR1.2 derivatives in which the carbazole-degradative car operon was deleted or its regulatory gene, antR, was deleted by homologous recombination between insertion sequences. From genomic information and quantitative reverse transcription-PCR analyses of the genes involved in carbazole mineralization by Pf0-1Km(pCAR1.2), we found that the cat genes on the chromosome of Pf0-1Km, which are necessary for the degradation of catechol (a toxic intermediate in the carbazole catabolic pathway), were not induced in the presence of carbazole. The resulting accumulation of catechol may have enabled the strain that lost its carbazole-degrading ability to have overall higher fitness than the wild-type strain. These results suggest that the functions of the chromosomal genes contributed to the selection of plasmid derivatives with altered structures.

  3. Interacción sinérgica entre hongos formadores de micorrizas arbusculares - Pseudomonas fluorescens y su relación en la nutrición vegetal de fósforo / Synergic interaction between arbuscular mycorrhizal fungi and Pseudomonas fluorescens and its effect on plant phosphorus uptake

    OpenAIRE

    Ordoñez Castañeda, Yuli Marcela

    2009-01-01

    Ciertos microorganismos (género Pseudomonas) y Hongos Formadores de Micorrizas Arbusculares (HFMA) tienen la habilidad de incrementar el fósforo disponible para la planta y mejorar la productividad de los cultivos agícolas. El uso coordinado de especies seleccionadas, tanto de bacterias como de HFMA, se convierte en una alternativa interesante, donde las bacterias liberan fosfatos y el micelio extraradical (MER) de este tipo de hongos puede movilizarlo hacia las raíces de la planta a la cual ...

  4. Growth of Pseudomonas fluorescens on Cassava Starch ...

    African Journals Online (AJOL)

    Michael Horsfall

    (Potassium sodium tartarate) and 1% (w/v) sodium hydroxide. To prepare 1 – litre of solution, 10 g of sodium hydroxide pellet was dissolved in 1- litre of distilled water. To this was added 10 g of powdered. 3,5 – Di-nitrosalicylic acid, 0.5 g of sodium bisulphite, 2.52 ml of 80% Phenol and stirred to complete dissolution.

  5. Characterization and identification of Pseudomonas fluorescens ...

    African Journals Online (AJOL)

    If you would like more information about how to print, save, and work with PDFs, Highwire Press provides a helpful Frequently Asked Questions about PDFs. Alternatively, you can download the PDF file directly to your computer, from where it can be opened using a PDF reader. To download the PDF, click the Download link ...

  6. Peudomonas fluorescens diversity and abundance in the rhizosphere

    Science.gov (United States)

    Amina, Melinai; Ahmed, Bensoltane; Khaladi, Mederbel

    2010-05-01

    It is now over 30 years since that a several plant associated strains of fluorescent Pseudomonas spp. are known to produce antimicrobial metabolites, playing a significant role in the biological control of a lot of plant diseases. For that, the interest in the use of these bacteria for biocontrol of plant pathogenic agents has increased. However, few comprehensive studies have described the abundance of this soil borne bacteria in the region of Mascara (Northern-Algerian West). In the connection of this problem, this work was done by monitoring the number of indigenous Pseudomonas fluorescens organisms in three stations characterizing different ecosystems, to document their abundance, diversity and investigate the relationship between P. fluorescens abundance and soil properties. Our quantitative plate counting results hence the conception of their ecology in the rhizosphere. Thus, quantitative results has confirmed that P. fluorescens are successful root colonizers with strong predominance and competed for many ecological niche, where their distribution were correlated significantly (P<0.05) with the majority of soil properties. Keywords: P. Fluorescens, Ecosystems, Abundance, Diversity, Correlated, Soil Properties.

  7. Bacteremia with Streptococcus pneumoniae

    DEFF Research Database (Denmark)

    Christensen, J S; Jensen, T G; Kolmos, H J

    2012-01-01

    We conducted a hospital-based cohort study among adult patients with first-time Streptococcus pneumoniae bacteremia (SPB) from 2000 through 2008. Patients were identified in a population-based bacteremia database and followed up for mortality through the Danish Civil Registration System (CRS...

  8. Optimization of alkaline protease production from Pseudomonas ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-15

    Dec 15, 2009 ... A protease producing bacteria was isolated from meat waste contaminated soil and identified as. Pseudomonas ... Key words: Alkaline protease, casein agar, meat waste contaminated soil, Pseudomonas fluorescens. INTRODUCTION ... advent of new frontiers in biotechnology, the spectrum of protease ...

  9. Dental bacteremia in children.

    Science.gov (United States)

    Roberts, G J; Holzel, H S; Sury, M R; Simmons, N A; Gardner, P; Longhurst, P

    1997-01-01

    Bacteremia resulting from dental extraction is regarded as an important cause of bacterial endocarditis, and it is therefore recommended that patients undergoing tooth extraction be given prophylactic antibiotics. As dental procedures other than extractions may also cause bacteremias, we studied a variety of dental procedures routinely used in pediatric dentistry. Blood samples for cultures were obtained 30 s after each of 13 dental operative procedures in 735 anesthetized children aged 2-16 years. Four procedures used for conservative dentistry caused bacteremias significantly more often than the baseline value of 9.4%: polishing teeth 24.5%, intraligamental injection 96.6%, rubber dam placement 29.4%, and matrix band with wedge placement 32.1%. In comparison, toothbrushing alone caused a bacteremia on 38.5% of occasions. The organisms isolated were typical of odontogenic bacteremias in that 50% of the isolates were identified as varieties of viridans streptococci. These data show that a wider variety of dental procedures than was previously documented cause bacteremia.

  10. Bacteremia in burned patients admitted to Sina Hospital, Tabriz, Iran

    Directory of Open Access Journals (Sweden)

    Parviz Saleh

    2014-11-01

    Full Text Available Introduction: One of the most important causes of mortality and morbidity in burn wards is infection, and it is the major reason of death in burn injuries. There are several reasons that make burn victims predisposed to infection. The current study aimed to investigate the role of different factors that have an effect on bacteremia occurrence in burn patients and factors which are relevant to mortality in these patients. Methods: This descriptive-analytic study conducted in a 1 year period in Sina Hospital, Tabriz University of Medical Sciences, Iran, and 81 burn were included. We collected patients’ data about their age, body weight, cause of burn, lesion color, place and percentage of burn by getting history and studying of their files. Then we documented all interventions. Blood tests and cultures and colonies criteria were recorded. Results: In this study, 39 patients were male (48.1%, and 42 was female (51.9%. Mean age was 32.06 ± 17.46 years. In patients without bacteremia, 57 patients did not need catheterization (89.1%, however in patients with bacteremia 9 patients demanded catheter insertion (52.9%. In patients with bacteremia 12 patients survived (70.9%, however in the without bacteremia group 56 patients survived (92.2%. Then, the relationship between type of burn, wound infection and bacterial species investigated, (P = 0.650, P = 0.210 and P = 0.110 respectively. Conclusion: We concluded, invasive interventions increased bacteremia susceptibility in our studied burned patients. Mortality rate is directly related to bacteremia prevalence and increased by extent of burn area in these patients. The three most frequent microbial agents responsible for bacteremia were Pseudomona aeruginosa, Klebsiella and Staphylococcus aureus.

  11. Control biológico del marchitamiento vascular causado por Fusarium oxysporum f. sp. phaseoli en fríjol Phaseolus vulgaris L., mediante la acción combinada de Entrophospora colombiana, Trichoderma sp. Y Pseudomonas fluorescens

    Directory of Open Access Journals (Sweden)

    Avendaño Camila

    2006-06-01

    Hidden="false" UnhideWhenUsed="false" QFormat="true" Name="Intense Emphasis" /> Entrophospora colombiana, Trichoderma sp., Pseudomonas fluorescens y una combinación de estos antagonistas fueron evaluados como biocontroladores de Fusarium oxysporumf. sp. Phaseoli en plantas de fríjol de la variedad ‘ICA Tundama’. El ensayo se estableció en una casa de malla del Programa nacional de manejo integrado de plagas (MIP de la Corporación Colombiana de Investigación Agropecuaria (Corpoica, en el Centro de Investigación Tibaitat

  12. A Direct Quantitative Agar-Plate Based Assay for Analysis of Pseudomonas protegens PF-5 Degradation of Polyurethane Films (Postprint)

    Science.gov (United States)

    2014-10-02

    activity in Pseudomonas fluorescens CHA0. Mol. Plant - Microbe . Interact . 25, 1440e1449. Yang, X., Wang, S., Zhou, L., 2012. Effect of carbon source, C... Interactions between the Pf-5 colonies and thin polyurethane (PU) coatings on ZnSe coupons were evaluated for degradation using infrared spectroscopy...Small (1 mm diameter) colonies of Pseudomonas protegens Pf-5 (formerly Pseudomonas fluorescens Pf-5) were used for this work. Interactions between

  13. Optimization of alkaline protease production from Pseudomonas ...

    African Journals Online (AJOL)

    A protease producing bacteria was isolated from meat waste contaminated soil and identified as Pseudomonas fluorescens. Optimization of the fermentation medium for maximum protease production was carried out. The culture conditions like inoculum concentration, incubation time, pH, temperature, carbon sources, ...

  14. Decreasing incidence rates of bacteremia

    DEFF Research Database (Denmark)

    Nielsen, Stig Lønberg; Pedersen, C; Jensen, T G

    2014-01-01

    ) and the incidence rate of nosocomial bacteremia decreased by 28.9% from 82.2 to 56.0 (4.2% annually, p Staphylococcus aureus (12.3%), coagulase-negative staphylococci (10.......0%) and Streptococcus pneumoniae (9.1%). Regardless of place of acquisition, the proportion of bacteremias caused by enterococci increased (p

  15. IMPORTANCE OF HEMOCULTURE IN DIAGNOSIS OF BACTEREMIA AND SEPSIS

    Directory of Open Access Journals (Sweden)

    Marina Dinic

    2006-01-01

    Full Text Available Almost all kinds of microorganisms from blood can be isolated by hemoculture. The isolate consists of 75–85% Gram negative and Gram positive bacteria, until the other part of the isolate consists of fungi or other microorganisms.During the three-year period (1998–2001 we analyzed microbiological characteristics of all positive hemocultures inspected in microbiological laboratory in the Public Health Institute in Nis as well as clinical parameters of patients with the aim of determining the cause of bacteremia. We applied standard microbiologic methods for inspection of 1995 hemocultures taken from 759 patients whereupon we registered positive medical findings in 18,75%. In the majority of cases only one kind of microorganisms was isolated, while in 1.06% of positive hemocultures we isoleted two kinds of microorganisms.Isolation of Streptococcus b heamolyticus gr. A, Streptococcus pneumoniae, E.coli, Proteus mirabilisa, Salmonellae enteritidis, Pseudomonas aeruginose i Candide spp confirms bacteremia. Difteroids and Bacillus spp. were isolated only from contaminated hemocultures. Staphylococcus epidermidis is the most frequent contminant and causes bacteremia in the patients with intravascular catheter and patients on intravenous and peritoneal dialysis. A similar finding of α hemolitic streptococcus of viridans group was registered in the patients with subacute and acute endocarditis who had had an intravenous catheter implanted.On the basis of the results obtained, we can conclude that microorganisms from groups of Streptococcus, Staphylococcus, Candida and Enterobacteriaceace family are the most frequent causes of bacteremia. Beside its limiting factors (time of sampling, duration of incubation, possible contamination of samples, number of hemocultures, hemoculture is the only method by which the causes of bacteremia and sepsis can be isolated.

  16. Bacteremia in Children Hospitalized with Respiratory Syncytial Virus Infection

    Science.gov (United States)

    Pardo-Seco, Jacobo; Gómez-Carballa, Alberto; Martinón-Torres, Nazareth; Martinón-Sánchez, José María; Justicia-Grande, Antonio; Rivero-Calle, Irene; Pinnock, Elli; Salas, Antonio; Fink, Colin

    2016-01-01

    Background The risk of bacteremia is considered low in children with acute bronchiolitis. However the rate of occult bacteremia in infants with RSV infection is not well established. The aim was to determine the actual rate and predictive factors of bacteremia in children admitted to hospital due to confirmed RSV acute respiratory illness (ARI), using both conventional culture and molecular techniques. Methods A prospective multicenter study (GENDRES-network) was conducted between 2011–2013 in children under the age of two admitted to hospital because of an ARI. Among those RSV-positive, bacterial presence in blood was assessed using PCR for Meningococcus, Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus pyogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, in addition to conventional cultures. Results 66 children with positive RSV respiratory illness were included. In 10.6% patients, bacterial presence was detected: H. influenzae (n = 4) and S. pneumoniae (n = 2). In those patients with bacteremia, there was a previous suspicion of bacterial superinfection and had received empirical antibiotic treatment 6 out of 7 (85.7%) patients. There were significant differences in terms of severity between children with positive bacterial PCR and those with negative results: PICU admission (100% vs. 50%, P-value = 0.015); respiratory support necessity (100% vs. 18.6%, P-value < 0.001); Wood-Downes score (mean = 8.7 vs. 4.8 points, P-value < 0.001); GENVIP scale (mean = 17 vs. 10.1, P-value < 0.001); and length of hospitalization (mean = 12.1 vs. 7.5 days, P-value = 0.007). Conclusion Bacteremia is not frequent in infants hospitalized with RSV respiratory infection, however, it should be considered in the most severe cases. PMID:26872131

  17. Risk factors for mortality in patients with nosocomial Gram-negative rod bacteremia.

    Science.gov (United States)

    Karakoc, C; Tekin, R; Yeşilbağ, Z; Cagatay, A

    2013-04-01

    The percentage of hospital-acquired bloodstream infections associated with Gram-negative bacilles has decreased during last decade but it is still a major cause of morbidity and mortality. The aim of this study was to determine the outcome of Gram-negative rod (GNR) bacteremia, which is an important clinical problem with high mortality rates, and the risk factors for GNR related mortality in our Clinic. During the study period, 520 episodes of bacteremia were detected in 411 patients. Only patients with GNR bacteremia in blood cultures were included in the study (n = 197). Among 197 patients fulfilling study criteria, GNR were grown in 239 samples. Escherichia coli (n = 97, 40.5%), Klebsiella pneumoniae (n = 54, 22.5%), Pseudomonas aeruginosa (n= 24, 10%), Acinetobacter baumannii (n = 24, 10%) were the most commonly isolated bacteria. The most frequently identified infection sources of bacteremia were pneumonia (n = 35, 17.7%), catheter-related infections (n = 24, 12.2%), urinary tract infections (n = 20, 10%). In multivariate analysis, it was found that the GNR bacteremia mortality risk increased in patients treated in intensive care units (ICU) (OR: 0.2, p = 0.03) and patients with ventilatory support (OR: 20.8, p = 0.05). In clinical practice of the hospital settings, efforts should concentrate on preventive measures for nosocomial infections since pneumonia, catheter-related infections, and urinary infections appear to be the most frequent causes of secondary bacteremia.    

  18. Bacteremias por bacilos gram-negativos

    Directory of Open Access Journals (Sweden)

    Adrelírio J. R. Gonçalves

    1969-01-01

    Full Text Available São apresentados 31 casos de bacteremia por gram-negativos, assunto que vem merecendo muita atenção dos pesquisadores nos últimos anos. Os organismos etiológicos mais importantes que apareceram em igualdade de freqüência foram Escherichia coli e Klebsiella-Aerobacter, sendo responsáveis por 58% do total das infecções, seguidos por Pseudomonas. A porta de entrada mais freqüente foi o trato urinário em 61,3% dos casos. A infecção foi mais comum no sexo masculino e a faixa etária de 50 a 60 anos predominou. O uso prévio de antibióticos foi um fator predisponente muito importante, seguido pelo uso de esteróides e citostáticos. As principais doenças predisponentes foram diabetes mellitus e neoplasias malignas. Os principais fatores precipitantes foram a manipulação do aparelho urinário, com infecção prévia ou desencadeada, cirurgia do aparelho digestivo, uronatia obstrutiva e obstrução biliar. As principais manifestações clínicas foram a presença de febre, calafrios e hipotensão arterial. A complicação mais freqüente foi o choque bacteriano que incidiu em 58% dos casos, aproximadamente três vêzes aquela relatada na literatura. As outras foram a insuficiência renal aguda, superinfecção e infecção pulmonar metastática. Considerações terapêuticas gerais e esquemas de antibióticos são propostos para estes casos. A mortalidade da bacteremia simples foi de 30,7% e quando associada ao choque elevou-se para 72,2% . As infecções por Pseudomonas foram 100% fatais.

  19. Novel Pseudomonas fluorescens Septic Sacroiliitis in a Healthy Soldier

    Science.gov (United States)

    2013-08-01

    pain and intermittent non-bloody diarrhea . Laboratory studies were unremarkable, concurrent abdominal computed tomography (CT) and lumbar MRI showed no...Microbiol 2008; 8: 189–202. 4. Dubey L, Krasinski K, Hernanz-Schulman M: Osteomyelitis secondary to trauma or infected contiguous soft tissue. Pediatr ...51. 17. Wu M-S, Chang S-S, Lee S-H, Lee C-C: Pyogenic sacroiliitis—a com- parison between pediatric and adult patients. Rheumatology 2007; 46: 1684–7

  20. Bacteremias in liver transplant recipients: shift toward gram-negative bacteria as predominant pathogens.

    Science.gov (United States)

    Singh, Nina; Wagener, Marilyn M; Obman, Asia; Cacciarelli, Thomas V; de Vera, Michael E; Gayowski, Timothy

    2004-07-01

    During the 1990s, gram-positive bacteria emerged as major pathogens after liver transplantation. We sought to determine whether the pathogens associated with bacteremias in liver transplant recipients have changed. Patients included 233 liver transplant recipients transplanted between 1989 and 2003. The proportion of all infections due to bacteremias increased significantly over time (P gram-negatives increased from 25% in the period of 1989-1993 to 51.8% in 1998-03, that of gram-positive bacteria decreased from 75% in the period of 1989-93 to 48.2% in the period of 1998-2003. Methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae, and Pseudomonas aeruginosa were the most frequent pathogens in bacteremic patients. The incidence of bacteremias due to MRSA and Pseudomonas aeruginosa has remained unchanged (P gram-negative bacteria, particularly Klebsiella pneumoniae has increased (P =.02). Klebsiella pneumoniae isolates in the current quartile were not clonally related. In conclusion, bacteremias as a proportion of all infections in liver transplant recipients have increased significantly over time, due in part to a decline in infections due to other major pathogens, e.g., fungi, primarily Candida species, and CMV. Gram-negative bacteria have emerged as predominant pathogens in bacteremic liver transplant recipients.

  1. Disruption of transporters affiliated with enantio-pyochelin biosynthesis gene cluster of Pseudomonas protegens Pf-5 has pleiotropic effects

    Science.gov (United States)

    Pseudomonas protegens Pf-5 (formerly Pseudomonas fluorescens) is a biocontrol bacterium that produces the siderophore enantio-pyochelin under conditions of iron starvation in a process that is often accompanied by the secretion of its biosynthesis intermediates, salicylic acid and dihydroaeruginoic ...

  2. Implementation of global antimicrobial resistance surveillance system (GLASS in patients with bacteremia.

    Directory of Open Access Journals (Sweden)

    Rujipas Sirijatuphat

    Full Text Available The global antimicrobial resistance surveillance system (GLASS was launched by the World Health Organization (WHO in 2015. GLASS is a surveillance system for clinical specimens that are sent to microbiology laboratory for clinical purposes. The unique feature of GLASS is that clinical data is combined with microbiological data, and deduplication of the microbiological results is performed. The objective of the study was to determine feasibility and benefit of GLASS for surveillance of blood culture specimens. GLASS was implemented at Siriraj Hospital in Bangkok, Thailand using a locally developed web application program (app to transfer blood culture specimen data, and to enter clinical data of patients with positive blood culture by infection control nurses and physicians via the app installed in their smart phones. The rate of positive blood culture specimens with true infection was 15.2%. Escherichia coli was the most common cause of bacteremia. Secondary bacteremia, primary bacteremia, and central line-associated blood stream infection was observed in 61.8%, 30.6%, and 12.6% of cases, respectively. Sepsis was observed in 56.9% of patients. E.coli was significantly more common in community-acquired bacteremia, whereas Klebsiella pneumoniae, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Acinetobacter baumannii were significantly more common in hospital-acquired bacteremia. Hospital-acquired isolates of E.coli, K.pneumoniae, A.baumannii, P.aeruginosa, S.aureus and Enterococcus faecium were more resistant to antibiotics than community-acquired isolates. In-hospital mortality was significantly higher in patients with antibiotic-resistant bacteremia than in patients with antibiotic non-resistant bacteremia (40.5% vs. 28.5%, p<0.001. The patients with antibiotic-resistant bacteremia consumed more resources than those with antibiotic non-resistant bacteremia. Blood culture results combined with patient clinical data were

  3. [Incidence and risk factors for bacteremia on pediatric patients with burns in a specialized care center in Mexico].

    Science.gov (United States)

    Chávez-Velarde, Teresa de J; Lona-Reyes, Juan C; Riebeling-Dueñas, Alejandra; Orozco-Alatorre, Luis G

    2017-06-01

    Bacteremia events are frequent cause of mortality in burn patients and may originate from infected wounds, by bacterial translocation of endogenous microorganisms, from invasive devices or contaminated intravenous solutions. To quantify the incidence of bacteremia in pediatric patients with burns and to identify risk factors. A prospective cohort study was performed in pediatric patients with burns of Hospital Civil de Guadalajara "Dr. Juan I. Menchaca". Bacteremia was diagnosed by blood cultures in patients with clinical manifestations of sepsis. Risk factors were investigated by multivariate analysis with Cox regression. Were included in the cohort 260 patients, median age 3 years. The incidence of bacteremia was 9.6 events per 1,000 days patient. The most frequently isolated bacteria were Enterobacteriaceae (41.9%), Staphylococcus aureus (22.6%) and Pseudomonas aeruginosa (22.6%). Factors associated with bacteremia were: bums ≥ 20% TBSA (HR 11.06; 95% CI 4.8-25.4), deep second degree bums or higher (HR 6.9; 95% CI 2.0-23.3) and have had two or less debridement (HR 26.4; 95% CI 8.0-87.7). Patients with more extensive and deep burns with fewer debridement are at increased risk of bacteremia.

  4. Cost Attributable to Nosocomial Bacteremia. Analysis According to Microorganism and Antimicrobial Sensitivity in a University Hospital in Barcelona.

    Directory of Open Access Journals (Sweden)

    Marta Riu

    Full Text Available To calculate the incremental cost of nosocomial bacteremia caused by the most common organisms, classified by their antimicrobial susceptibility.We selected patients who developed nosocomial bacteremia caused by Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, or Pseudomonas aeruginosa. These microorganisms were analyzed because of their high prevalence and they frequently present multidrug resistance. A control group consisted of patients classified within the same all-patient refined-diagnosis related group without bacteremia. Our hospital has an established cost accounting system (full-costing that uses activity-based criteria to analyze cost distribution. A logistic regression model was fitted to estimate the probability of developing bacteremia for each admission (propensity score and was used for propensity score matching adjustment. Subsequently, the propensity score was included in an econometric model to adjust the incremental cost of patients who developed bacteremia, as well as differences in this cost, depending on whether the microorganism was multidrug-resistant or multidrug-sensitive.A total of 571 admissions with bacteremia matched the inclusion criteria and 82,022 were included in the control group. The mean cost was € 25,891 for admissions with bacteremia and € 6,750 for those without bacteremia. The mean incremental cost was estimated at € 15,151 (CI, € 11,570 to € 18,733. Multidrug-resistant P. aeruginosa bacteremia had the highest mean incremental cost, € 44,709 (CI, € 34,559 to € 54,859. Antimicrobial-susceptible E. coli nosocomial bacteremia had the lowest mean incremental cost, € 10,481 (CI, € 8,752 to € 12,210. Despite their lower cost, episodes of antimicrobial-susceptible E. coli nosocomial bacteremia had a major impact due to their high frequency.Adjustment of hospital cost according to the organism causing bacteremia and antibiotic sensitivity could improve prevention strategies

  5. Bacteremia and candidemia in hematological malignancies

    DEFF Research Database (Denmark)

    Hovgaard, D; Skinhøj, P; Bangsborg, Jette Marie

    1988-01-01

    171 episodes of bacteremia and candidemia in 142 patients were recorded during the period 1981-1985 in patients with hematological malignancies. Overall mortality, within 1 week of onset of bacteremia, was 20%. Increased mortality was found in patients with poor disease-prognosis (39%), with gran...

  6. Risk factors and outcomes of bacteremia caused by drug-resistant ESKAPE pathogens in solid-organ transplant recipients.

    Science.gov (United States)

    Bodro, Marta; Sabé, Núria; Tubau, Fe; Lladó, Laura; Baliellas, Carme; Roca, Josep; Cruzado, Josep Maria; Carratalà, Jordi

    2013-11-15

    Although infections due to the six ESKAPE pathogens have recently been identified as a serious emerging problem, information regarding bacteremia caused by these organisms in solid-organ transplant (SOT) recipients is lacking. We sought to determine the frequency, risk factors, and outcomes of bacteremia due to drug-resistant ESKAPE (rESKAPE) organisms in liver, kidney, and heart adult transplant recipients. All episodes of bacteremia prospectively documented in hospitalized SOT recipients from 2007 to 2012 were analyzed. Of 276 episodes of bacteremia, 54 (19.6%) were due to rESKAPE strains (vancomycin-resistant Enterococcus faecium [0], methicillin-resistant Staphylococcus aureus [5], extended-spectrum β-lactamase-producing Klebsiella pneumoniae [10], carbapenem-resistant Acinetobacter baumannii [8], carbapenem- and quinolone-resistant Pseudomonas aeruginosa [26], and derepressed chromosomal β-lactam and extended-spectrum β-lactamase-producing Enterobacter species [5]). Factors independently associated with rESKAPE bacteremia were prior transplantation, septic shock, and prior antibiotic therapy. Patients with rESKAPE bacteremia more often received inappropriate empirical antibiotic therapy than the others (41% vs. 21.6%; P=0.01). Overall case-fatality rate (30 days) was higher in patients with rESKAPE bacteremia (35.2% vs. 14.4%; P=0.001). Bacteremia due to rESKAPE pathogens is frequent in SOT recipients and causes significant morbidity and mortality. rESKAPE organisms should be considered when selecting empirical antibiotic therapy for hospitalized SOT recipients presenting with septic shock, particularly those with prior transplantation and antibiotic use.

  7. Actinomyces turicensis Bacteremia Secondary to Pyometra.

    Science.gov (United States)

    Hagiya, Hideharu; Ogawa, Hiroko; Takahashi, Yusuke; Kimura, Kosuke; Hasegawa, Kan; Otsuka, Fumio

    2015-01-01

    We herein present a rare case of Actinomyces turicensis bacteremia that was caused by pyometra. The patient was successfully treated with transvaginal drainage and antibiotic therapy. A literature review in MEDLINE showed that there have been only 8 previously reported cases of A. turicensis bacteremia. This infection frequently occurs in patients with visceral abscesses, and blood culture examinations usually reveal a polymicrobial pattern. However, the prognosis of such patients has been reported to generally be benign. Due to difficulties in performing bacterial identification and the wide-spectrum clinical pictures associated with this bacteremia, no comprehensive understanding of the clinical features of each Actinomyces species has yet been established.

  8. Bacteremia

    Science.gov (United States)

    ... Summer Camp Tips for Kids With Asthma, Allergies Antioxidants: The Good Health Helpers As Stroke 'Liquefies' Brain ... Mouth and Dental Disorders Older People’s Health Issues Skin Disorders Special Subjects Women's Health Issues Symptoms ALL ...

  9. Phenazine-producing fluorescent Pseudomonas spp.: Diversity and biogeography in central Washington state

    Science.gov (United States)

    Strains of the rhizosphere bacterium Pseudomonas fluorescens produce redox-active phenazine antibiotics that suppress a wide variety of soilborne plant pathogens. Our laboratory recently detected these bacteria a population levels up to 106 colony-forming units (cfu) per gram of root (fresh weight)...

  10. Chemical sanitizers to control biofilms formed by two Pseudomonas species on stainless steel surface

    Directory of Open Access Journals (Sweden)

    Danila Soares Caixeta

    2012-03-01

    Full Text Available The biofilm formation of Pseudomonas aeruginosa and Pseudomonas fluorescens on AISI 304 stainless steel in the presence of reconstituted skim milk under different temperatures was conducted, and the potential of three chemical sanitizers in removing the mono-species biofilms formed was compared. Pseudomonas aeruginosa cultivated in skim milk at 28 °C presented better growth rate (10.4 log CFU.mL-1 when compared with 3.7 and 4.2 log CFU.mL-1 for P. aeruginosa and P. fluorescens cultivated at 7 °C, respectively. Pseudomonas aeruginosa formed biofilm when cultivated at 28 °C. However, only the adhesion of P. aeruginosa and P. fluorescens was observed when incubated at 7 °C. The sodium dichloroisocyanurate was the most efficient sanitizer in the reduction of the adhered P. aeruginosa cells at 7 and 28 °C and those on the biofilm, respectively. The hydrogen peroxide was more effective in the reduction of adhered cells of P. fluorescens at 7 °C.

  11. 40 CFR 180.1107 - Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Delta endotoxin of Bacillus... From Tolerances § 180.1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta endotoxin of...

  12. Polymicrobial Bacteremia Involving Comamonas testosteroni

    Directory of Open Access Journals (Sweden)

    Jose Orsini

    2014-01-01

    Full Text Available Comamonas spp. are uncommon isolates in microbiology laboratories and have been rarely observed as an infectious agent in clinical practice. They have widespread environmental distribution and have been isolated from water, soil, and plants as well as from some hospital devices such as intravenous catheters and water contained in humidifier reservoirs used in respiratory treatment. The genus Comamonas originally contained the following species: acidovorans, testosteroni, kerstersii, terrigena, denitrificans, and nitrativorans. It now contains 17 species, while acidovorans spp. have been reclassified as Delftia acidovorans. In spite of its uncommon human pathogenesis, there are few reports on the aggressive manner of it as an opportunistic pathogen, mostly related to testosteroni spp. We present a case of polymicrobial bacteremia involving Comamonas testosteroni. The aim of this case report is to alert clinicians to the potential diagnosis of bloodstream infections caused by uncommon pathogens.

  13. Bacteremia during quinsy and elective tonsillectomy

    DEFF Research Database (Denmark)

    Klug, Tejs Ehlers; Henriksen, Jens-Jacob; Rusan, Maria

    2012-01-01

    Abstract Aims: Bacteremia during elective tonsillectomy is well recognized, whereas bacteremia during quinsy tonsillectomy has never been studied. The aim of the present study was to explore the incidence of bacteremia during elective and quinsy tonsillectomy in order to evaluate the antibiotic...... prophylaxis recommendations to patients at high risk of infective endocarditis who are undergoing tonsillectomy. Methods: A prospective study was conducted on 80 patients undergoing elective tonsillectomy and 36 patients undergoing acute tonsillectomy due to peritonsillar abscess. Blood cultures, tonsillar...... swabs, core tissue, and pus aspirates were analyzed by standard microbiological techniques. Results: Bacteremia was detected in 73% of patients during elective tonsillectomy compared to 56% during quinsy tonsillectomy (P ¼ .089, Fishers exact test). Significantly more blood culture bottles were positive...

  14. Bacteremia and fungemia in patients with the acquired immunodeficiency syndrome.

    Science.gov (United States)

    Whimbey, E; Gold, J W; Polsky, B; Dryjanski, J; Hawkins, C; Blevins, A; Brannon, P; Kiehn, T E; Brown, A E; Armstrong, D

    1986-04-01

    Forty-nine episodes of bacteremia and fungemia occurred in 38 of 336 patients with the acquired immunodeficiency syndrome seen at our institution since 1980. There were five types of infections. Infections commonly associated with a T-cell immunodeficiency disorder comprised 16 episodes and included those with Salmonella species, Listeria monocytogenes, Cryptococcus neoformans, and Histoplasma capsulatum. Infections commonly associated with a B-cell immunodeficiency disorder included those with Streptococcus pneumoniae and Haemophilus influenzae. Infections occurring with neutropenia were caused by Pseudomonas aeruginosa, Staphylococcus epidermidis, and Streptococcus faecalis. Other infections occurring in the hospital were caused by Candida albicans, Staphylococcus epidermidis, enteric gram-negative rods, Staphylococcus aureus, and mixed S. aureus and group G streptococcus. Other infections occurring out of the hospital included those with S. aureus, Clostridium perfringens, Shigella sonnei, Pseudomonas aeruginosa, and group B streptococcus. Because two thirds of the septicemias were caused by organisms other than T-cell opportunists, these pathogens should be anticipated during diagnostic evaluation and when formulating empiric therapy.

  15. The Pseudomonas aeruginosa oxyvinylglycine L-2-amino-4-methoxy-trans-3-butenoic acid inhibits growth of Erwinia amylovora and acts as a weak seed germination-arrest factor

    Science.gov (United States)

    The Pseudomonas aeruginosa antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid (AMB) is demonstrated to share biological activities with 4-formylaminooxyvinylglycine, a related molecule produced by Pseudomonas fluorescens WH6. We found that culture filtrates of a P. aeruginosa strain overproduc...

  16. Two cases of Ruminococcus gnavus bacteremia associated with diverticulitis

    DEFF Research Database (Denmark)

    Hansen, Sanne Grønvall Kjær; Skov, Marianne N; Justesen, Ulrik S

    2013-01-01

    We report two cases of bacteremia with the anaerobic bacterium Ruminococcus gnavus. In both cases, the bacteremia was associated with diverticular disease. Preliminary conventional identification suggested peptostreptococci, and matrix-assisted laser desorption ionization-time of flight mass spec...

  17. Protozoan growth rates on secondary-metabolite-producing Pseudomonas spp. correlate with high-level protozoan taxonomy

    DEFF Research Database (Denmark)

    Pedersen, Annette L.; Winding, Anne; Altenburger, Andreas

    2011-01-01

    Different features can protect bacteria against protozoan grazing, for example large size, rapid movement, and production of secondary metabolites. Most papers dealing with these matters focus on bacteria. Here, we describe protozoan features that affect their ability to grow on secondary......-metabolite-producing bacteria, and examine whether different bacterial secondary metabolites affect protozoa similarly. We investigated the growth of nine different soil protozoa on six different Pseudomonas strains, including the four secondary-metabolite-producing Pseudomonas fluorescens DR54 and CHA0, Pseudomonas...... chlororaphis MA342 and Pseudomonas sp. DSS73, as well as the two nonproducers P. fluorescens DSM50090T and P. chlororaphis ATCC43928. Secondary metabolite producers affected protozoan growth differently. In particular, bacteria with extracellular secondary metabolites seemed more inhibiting than bacteria...

  18. Diversity of Pseudomonas Genomes, Including Populus-Associated Isolates, as Revealed by Comparative Genome Analysis

    Science.gov (United States)

    Jun, Se-Ran; Wassenaar, Trudy M.; Nookaew, Intawat; Hauser, Loren; Wanchai, Visanu; Land, Miriam; Timm, Collin M.; Lu, Tse-Yuan S.; Schadt, Christopher W.; Doktycz, Mitchel J.; Pelletier, Dale A.

    2015-01-01

    The Pseudomonas genus contains a metabolically versatile group of organisms that are known to occupy numerous ecological niches, including the rhizosphere and endosphere of many plants. Their diversity influences the phylogenetic diversity and heterogeneity of these communities. On the basis of average amino acid identity, comparative genome analysis of >1,000 Pseudomonas genomes, including 21 Pseudomonas strains isolated from the roots of native Populus deltoides (eastern cottonwood) trees resulted in consistent and robust genomic clusters with phylogenetic homogeneity. All Pseudomonas aeruginosa genomes clustered together, and these were clearly distinct from other Pseudomonas species groups on the basis of pangenome and core genome analyses. In contrast, the genomes of Pseudomonas fluorescens were organized into 20 distinct genomic clusters, representing enormous diversity and heterogeneity. Most of our 21 Populus-associated isolates formed three distinct subgroups within the major P. fluorescens group, supported by pathway profile analysis, while two isolates were more closely related to Pseudomonas chlororaphis and Pseudomonas putida. Genes specific to Populus-associated subgroups were identified. Genes specific to subgroup 1 include several sensory systems that act in two-component signal transduction, a TonB-dependent receptor, and a phosphorelay sensor. Genes specific to subgroup 2 contain hypothetical genes, and genes specific to subgroup 3 were annotated with hydrolase activity. This study justifies the need to sequence multiple isolates, especially from P. fluorescens, which displays the most genetic variation, in order to study functional capabilities from a pangenomic perspective. This information will prove useful when choosing Pseudomonas strains for use to promote growth and increase disease resistance in plants. PMID:26519390

  19. 40 CFR 180.1108 - Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas...

    Science.gov (United States)

    2010-07-01

    ... From Tolerances § 180.1108 Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated... of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas fluorescens is... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Delta endotoxin of Bacillus...

  20. Effect of Genetically Modified Pseudomonas putida WCS358r on the Fungal Rhizosphere Microflora of Field-Grown Wheat

    NARCIS (Netherlands)

    Glandorf, D.C.M.; Verheggen, Patrick; Jansen, Timo; Jorritsma, J.-W.; Smit, Eric; Leeflang, Paula; Wernars, Karel; Thomashow, L.S.; Laureijs, Eric; Thomas-Oates, J.E.; Bakker, P.A.H.M.; Loon, L.C. van

    2001-01-01

    We released genetically modified Pseudomonas putida WCS358r into the rhizospheres of wheat plants. The two genetically modified derivatives, genetically modified microorganism (GMM) 2 and GMM 8, carried the phz biosynthetic gene locus of strain P. fluorescens 2-79 and constitutively produced the

  1. Chemical sanitizers to control biofilms formed by two Pseudomonas species on stainless steel surface Sanificantes químicos no controle de biofilmes formados por duas espécies de Pseudomonas em superfície de aço inoxidável

    Directory of Open Access Journals (Sweden)

    Danila Soares Caixeta

    2012-03-01

    Full Text Available The biofilm formation of Pseudomonas aeruginosa and Pseudomonas fluorescens on AISI 304 stainless steel in the presence of reconstituted skim milk under different temperatures was conducted, and the potential of three chemical sanitizers in removing the mono-species biofilms formed was compared. Pseudomonas aeruginosa cultivated in skim milk at 28 °C presented better growth rate (10.4 log CFU.mL-1 when compared with 3.7 and 4.2 log CFU.mL-1 for P. aeruginosa and P. fluorescens cultivated at 7 °C, respectively. Pseudomonas aeruginosa formed biofilm when cultivated at 28 °C. However, only the adhesion of P. aeruginosa and P. fluorescens was observed when incubated at 7 °C. The sodium dichloroisocyanurate was the most efficient sanitizer in the reduction of the adhered P. aeruginosa cells at 7 and 28 °C and those on the biofilm, respectively. The hydrogen peroxide was more effective in the reduction of adhered cells of P. fluorescens at 7 °C.A capacidade de adesão e formação de biofilme por Pseudomonas aeruginosa e Pseudomonas fluorescens em aço inoxidável AISI 304, na presença de leite desnatado resconstituído sobre diferentes temperaturas foi conduzido e o potencial de três sanificantes químicos na remoção de biofilmes monoespécies foi comparado. Pseudomonas aeruginosa cultivada em leite desnatado a 28 °C apresentou melhor crescimento (10,4 log UFC.mL-1 quando comparado com 3,7 and 4,2 log UFC.mL-1 para P. aeruginosa e P. fluorescens cultivadas a 7 °C, respectivamente. Pseudomonas aeruginosa formou biofilme quando cultivada a 28 °C. Contudo foi observado somente adesão de P. aeruginosa e P. fluorescens quando incubada a 7 °C. O dicloroisocianurato de sódio foi o sanificante mais eficiente na redução de células aderidas e em biofilme de P. aeruginosa a 7 e 28 °C, respectivamente. O peróxido de hidrogênio foi o mais eficiente na redução de células aderidas de P. fluorescens a 7 °C.

  2. [Trends for bacteremia and risk factors for death in a tertiary hospital in Mexico City. 1981-1992].

    Science.gov (United States)

    Sifuentes-Osornio, J; Guerrero-Almeida, M C; Ponce de León-Garduño, L A; Guerrero-Almeida, M L

    2001-01-01

    To describe the trends and risk factors of death for bacteremia in adult from a tertiary-care center from 1981 to 1992. We randomly included 20% of bacteremic episodes per year. 47,618 blood-cultures from 19,530 patients, 3428 patients (17.6%) had bacteremia (285/y). From 600 episodes (50/y), 307 were from men, 368 were hospital-acquired (HA), and 88% were monomicrobial. Diabetes mellitus was seen in 103 cases, cirrhosis of the liver in 98, and AIDS in 33, among others. The main microorganisms were: Escherichia coli (177), Klebsiella pneumoniae (53), Enterobacter (50), Salmonella (45) and Pseudomonas aeruginosa (35); coagulase-negative staphylococci (CNS) (116), Staphylococcus aureus (56), and enterococci (22), and Candida (20). CNS decreased during the study (p mortality of the HA bacteremia was 70.8%, and 29.2% in the case of community-acquired, the mortality attributable to HA bacteremia was 41.6%. The main risk factors were: cardiac valvular disease (p mortality during the study period that has not change despite opportune therapy, Enterococci and candida have emerged as significant pathogens.

  3. Fatal Case of Listeria innocua Bacteremia

    OpenAIRE

    Perrin, Monique; Bemer, Michel; Delamare, Catherine

    2003-01-01

    Listeria innocua is widespread in the environment and in food. This species has to date never been described in association with human disease. We report a case of fatal bacteremia caused by L. innocua in a 62-year-old patient.

  4. Fatal case of Listeria innocua bacteremia.

    Science.gov (United States)

    Perrin, Monique; Bemer, Michel; Delamare, Catherine

    2003-11-01

    Listeria innocua is widespread in the environment and in food. This species has to date never been described in association with human disease. We report a case of fatal bacteremia caused by L. innocua in a 62-year-old patient.

  5. Molecular Epidemiology of Enterococcal Bacteremia in Australia

    Science.gov (United States)

    Pearson, Julie C.; Daley, Denise A.; Le, Tam; Robinson, Owen J.; Gottlieb, Thomas; Howden, Benjamin P.; Johnson, Paul D. R.; Bennett, Catherine M.; Stinear, Timothy P.; Turnidge, John D.

    2014-01-01

    Enterococci are a major cause of health care-associated infections and account for approximately 10% of all bacteremias globally. The aim of this study was to determine the proportion of enterococcal bacteremia isolates in Australia that are antimicrobial resistant, with particular emphasis on susceptibility to ampicillin and the glycopeptides, and to characterize the molecular epidemiology of the Enterococcus faecalis and Enterococcus faecium isolates. From 1 January to 31 December 2011, 1,079 unique episodes of bacteremia were investigated, of which 95.8% were caused by either E. faecalis (61.0%) or E. faecium (34.8%). The majority of bacteremias were health care associated, and approximately one-third were polymicrobial. Ampicillin resistance was detected in 90.4% of E. faecium isolates but was not detected in E. faecalis isolates. Vancomycin nonsusceptibility was reported in 0.6% and 36.5% of E. faecalis and E. faecium isolates, respectively. Unlike Europe and the United States, where vancomycin resistance in E. faecium is predominately due to the acquisition of the vanA operon, 98.4% of E. faecium isolates harboring van genes carried the vanB operon, and 16.1% of the vanB E. faecium isolates had vancomycin MICs at or below the susceptible breakpoint of the CLSI. Although molecular typing identified 126 E. faecalis pulsed-field gel electrophoresis pulsotypes, >50% belonged to two pulsotypes that were isolated across Australia. E. faecium consisted of 73 pulsotypes from which 43 multilocus sequence types were identified. Almost 90% of the E. faecium isolates were identified as CC17 clones, of which approximately half were characterized as ST203, which was isolated Australia-wide. In conclusion, the Australian Enterococcal Sepsis Outcome Programme (AESOP) study has shown that although they are polyclonal, enterococcal bacteremias in Australia are frequently caused by ampicillin-resistant vanB E. faecium. PMID:24391201

  6. Generation and initial characterization of Pseudomonas stutzeri KC mutants with impaired ability to degrade carbon tetrachloride.

    Science.gov (United States)

    Sepúlveda-Torres, L C; Rajendran, N; Dybas, M J; Criddle, C S

    1999-01-01

    Under iron-limiting conditions, Pseudomonas stutzeri KC secretes a small but as yet unidentified factor that transforms carbon tetrachloride (CT) to CO2 and nonvolatile products when activated by reduction at cell membranes. Pseudomonas fluorescens and other cell types activate the factor. Triparental mating was used to generate kanamycin-resistant lux::Tn5 recombinants of strain KC. Recombinants were streaked onto the surface of agar medium plugs in microtiter plates and were then screened for carbon tetrachloride degradation by exposing the plates to gaseous 14C-carbon tetrachloride. CT+ recombinants generated nonvolatile 14C-labeled products, but four CT- recombinants did not generate significant nonvolatile 14C-labeled products and had lost the ability to degrade carbon tetrachloride. When colonies of P. fluorescens were grown next to colonies of CT+ recombinants and were exposed to gaseous 14C-carbon tetrachloride, 14C-labeled products accumulated around the P. fluorescens colonies, indicating that the factor secreted by CT+ colonies had diffused through the agar and become activated. When P. fluorescens was grown next to CT- colonies, little carbon tetrachloride transformation was observed, indicating a lack of active factor. Expression of lux reporter genes in three of the CT- mutants was regulated by added iron and was induced under the same iron-limiting conditions that induce carbon tetrachloride transformation in the wild-type.

  7. Chromosomal insertion of the entire Escherichia coli lactose operon, into two strains of Pseudomonas, using a modified mini-Tn5 delivery system

    DEFF Research Database (Denmark)

    Hansen, L. H.; Sørensen, S. J.; Jensen, Lars Bogø

    1997-01-01

    A 12-kb PstI fragment including the entire E. coli lactose operon (lacIPOZYA) was inserted in one copy into the chromosome of Pseudomonas putida, Pseudomonas fluorescens and an E. coli strain with lac(-) phenotype. This was made possible by improvements of an already existing mini-Tn5 transposon...... flanked by NotI sites needed in the mini-Tn5 delivery system; (b) the generation of E. coli nonlysogenic strains expressing the pi protein thus being capable of maintaining and delivering R6K-based mini-Tn5 vectors to other E. coli strains; (c) the successful insertion of the E. coli lactose operon...... into the P. fluorescens chromosome giving P. fluorescens the ability to grow on lactose; (d) evidence from Southern blotting that contradicts the assumption that the mini-Tn5 delivery system always creates one-copy inserts. These improvements allow insertion of large DNA fragments encoding highly expressed...

  8. [Mycoplasma hominis bacteremia. An underestimated etiological agent].

    Science.gov (United States)

    Posse, Tamara; Prieto, Monica; Cipolla, Lucia; Kaufman, Sara

    2017-10-17

    Mycoplasma hominis is a fastidious bacterium, which usually colonizes the lower urogenital tract and may cause systemic infections in neonates and genital infections in adults. It can also be the cause of serious extra-genital infections, mainly in immunosuppressed or predisposed subjects. We describe a case of bacteremia caused by M. hominis in a previously healthy woman after uterine curettage due to incomplete abortion. M. hominis could be an underestimated cause of bacteremia in immunocompetent patients. Mycoplasma organisms have fastidious growth requirements, are often difficult to culture on a cell-free medium and have no cell wall. The conventional method for detection may fail. This is the first report of M. hominis isolation from a positive automated blood culture (BD BACTEC, USA). Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. Pasteurella multocida Bacteremia in an Immunocompromised Patient

    Directory of Open Access Journals (Sweden)

    Shweta Kukrety

    2016-01-01

    Full Text Available We present the case of a 61-year-old Caucasian gentleman who presented with a one-day history of fever, chills, and altered mental status. His symptoms were initially thought to be secondary to cellulitis. Blood cultures grew Pasteurella multocida, a rare pathogen to cause bacteremia. Our patient was treated with ciprofloxacin for two weeks and made a complete and uneventful recovery. Our patient’s uncontrolled diabetes mellitus and chronic kidney disease put him at a higher risk for developing serious P. multocida infection. The patient’s dog licking the wounds on his legs was considered as the possible source of infection. As P. multicoda bacteremia is rare, but severe with a high mortality rate, it is imperative to have a high index of suspicion for this infection especially in the vulnerable immunocompromised population.

  10. Macrophage serum markers in pneumococcal bacteremia

    DEFF Research Database (Denmark)

    Møller, Holger Jon; Moestrup, Søren K; Weis, Nina

    2006-01-01

    with pneumococcal bacteremia. DESIGN: Observational cohort study. SETTING: Five university hospitals in Denmark. PATIENTS: A total of 133 patients with Streptococcus pneumoniae bacteremia (positive blood culture) and 133 age- and gender-matched controls. INTERVENTIONS: Samples were collected for biochemical...... analyses at the time of first positive blood culture. MEASUREMENTS AND MAIN RESULTS: sCD163 was highly correlated with other macrophage markers and was significantly elevated (median [25-75 percentiles], 4.6 mg/L [2.8-8.9]) compared with healthy controls (2.7 mg/L [2.1-3.3], p ... were observed in patients who needed intensive care (hemodialysis, p = .0011; hypotension, p = .0014; mechanical ventilation, p = .0019). Significantly lower levels of sCD163, ferritin, transcobalamin, and suPAR (but not C-reactive protein) were measured in patients > or =75 yrs. In patients

  11. Microbiology of odontogenic bacteremia: beyond endocarditis.

    Science.gov (United States)

    Parahitiyawa, N B; Jin, L J; Leung, W K; Yam, W C; Samaranayake, L P

    2009-01-01

    The human gingival niche is a unique microbial habitat. In this habitat, biofilm organisms exist in harmony, attached to either enamel or cemental surfaces of the tooth as well as to the crevicular epithelium, subjacent to a rich vascular plexus underneath. Due to this extraordinary anatomical juxtaposition, plaque biofilm bacteria have a ready portal of ingress into the systemic circulation in both health and disease. Yet the frequency, magnitude, and etiology of bacteremias due to oral origin and the consequent end organ infections are not clear and have not recently been evaluated. In this comprehensive review, we address the available literature on triggering events, incidence, and diversity of odontogenic bacteremias. The nature of the infective agents and end organ infections (other than endocarditis) is also described, with an emphasis on the challenge of establishing the link between odontogenic infections and related systemic, focal infections.

  12. Incidence of bacteremia after chewing, tooth brushing and scaling in individuals with periodontal inflammation

    DEFF Research Database (Denmark)

    Forner, Lone; Larsen, Tove; Kilian, Mogens

    2006-01-01

    SCIENTIFIC RATIONALE FOR STUDY: Bacteremia occurs with various frequency after oral procedures. Periodontal disease may affect the incidence, magnitude, duration and bacterial spectrum of bacteremia. PRINCIPLE FINDINGS: The incidence and magnitude of bacteremia after scaling was significantly hig...

  13. Bacillus cereus Bacteremia in a Preterm Neonate

    OpenAIRE

    Hilliard, Nicholaus J; Schelonka, Robert L.; Waites, Ken B.

    2003-01-01

    Bacillus cereus is an uncommon but potentially serious bacterial pathogen causing infections of the bloodstream, lungs, and central nervous system of preterm neonates. A case of bacteremia caused by B. cereus in a 19-day-old preterm neonate who was successfully treated with vancomycin, tobramycin, meropenem, and clindamycin is described. Implications for the diagnostic laboratory and clinicians when Bacillus species are detected in normally sterile sites are discussed, and the small numbers o...

  14. Bacteremia following dental implant surgery: Preliminary results

    OpenAIRE

    Bölükbas, Nilüfer; Özdemi, Tayfun; Öksüz, Lütfiye; Gürler, Nezahat

    2011-01-01

    Objectives: The aims of this study were to investigate the incidence of bacteremia, bacteriology and antibiotic susceptibility against to causative bacteria associated with dental implant installation. Study Design: 30 generally healthy patients were enrolled in this study. Blood samples were collected at baseline and at 30 minutes after dental implant installation and 24 hours after dental implant surgery. Blood samples were cultured in a BACTEC system. The isolated bacteria were identified ...

  15. [Isolation of Bordetella trematum from bacteremia].

    Science.gov (United States)

    Halim, Ilham; Ihbibane, Fatima; Belabbes, Houria; Zerouali, Khalid; El Mdaghri, Naima

    2014-01-01

    The species Bordetella trematum was first described in 1996. Currently only eleven cases were published. We describe the first case of Bordetella trematum issued from bacteremia with a patient who has severe burns in Morocco. The identification was not possible by conventional microbiological methods where the resort to 16S ARNr sequencing. The use of molecular methods, including sequencing of the 16S ARNr, is currently an essential complementary tool to identify microbiological pathogens.

  16. Update on detection of bacteremia and fungemia.

    OpenAIRE

    Reimer, L G; M. L. Wilson; Weinstein, M P

    1997-01-01

    The presence of microorganisms in a patient's blood is a critical determinant of the severity of the patient's illness. Equally important, the laboratory isolation and identification of a microorganism present in blood determine the etiologic agent of infection, especially when the site of infection is localized and difficult to access. This review addresses the pathophysiology and clinical characteristics of bacteremia, fungemia, and sepsis; diagnostic strategies and critical factors in the ...

  17. Variation of the Pseudomonas community structure on oak leaf lettuce during storage detected by culture-dependent and -independent methods.

    Science.gov (United States)

    Nübling, Simone; Schmidt, Herbert; Weiss, Agnes

    2016-01-04

    The genus Pseudomonas plays an important role in the lettuce leaf microbiota and certain species can induce spoilage. The aim of this study was to investigate the occurrence and diversity of Pseudomonas spp. on oak leaf lettuce and to follow their community shift during a six day cold storage with culture-dependent and culture-independent methods. In total, 21 analysed partial Pseudomonas 16S rRNA gene sequences matched closely (> 98.3%) to the different reference strain sequences, which were distributed among 13 different phylogenetic groups or subgroups within the genus Pseudomonas. It could be shown that all detected Pseudomonas species belonged to the P. fluorescens lineage. In the culture-dependent analysis, 73% of the isolates at day 0 and 79% of the isolates at day 6 belonged to the P. fluorescens subgroup. The second most frequent group, with 12% of the isolates, was the P. koreensis subgroup. This subgroup was only detected at day 0. In the culture-independent analysis the P. fluorescens subgroup and P. extremaustralis could not be differentiated by RFLP. Both groups were most abundant and amounted to approximately 46% at day 0 and 79% at day 6. The phytopathogenic species P. salmonii, P. viridiflava and P. marginalis increased during storage. Both approaches identified the P. fluorescens group as the main phylogenetic group. The results of the present study suggest that pseudomonads found by plating methods indeed represent the most abundant part of the Pseudomonas community on oak leaf lettuce. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Investigation of bacteremia after separator placement

    Directory of Open Access Journals (Sweden)

    Anjuman Preet Kaur Dua

    2016-01-01

    Full Text Available Background: Simple orthodontic procedure such as separator placement can be associated with the occurrence of transient bacteraemia. Use of clorhexidine before separator placement has been recommended as a measure to decrease the bacteraemia. Aim: The purpose of this study was to detect the presence of transient bacteremia after separator placement following use of 0.2% chlorhexidine gluconate mouthwash. Methodology: The study group consisted of 27 adult patients who reported for orthodontic treatment (18 males and 9 females. The patients were asked to rinse their mouth for 60 sec with 15 mL of 0.2% chlorhexidine gluconate mouthwash before the separator placement. An aseptic technique was used to draw out 5 ml of blood was from either the left or right antecubital fossa immediately before orthodontic separator placement (as control group, and the second 5 ml sample was taken 1–2 min after the placement of separators mesial and distal to all the first molars. All the blood samples were inoculated into culture bottles containing Brain Heart Infusion and incubated aerobically for 7 days. Media used for bacterial growth is chocolate agar and MacConkey agar. Results: From a total of 27 patients and 54 samples, none of the sample was found positive for bacteremia. Conclusion: This study demonstrated that there is no bacteremia after the placement of separators following the use of chlorhexidine mouthwash.

  19. Two strains of Pseudomonas fluorscens bacteria differentially affect survivorship of waxworm (Galleria mellonella) larvae exposed to an arthropod fungal pathogen, Beauveria bassiana

    Science.gov (United States)

    Two strains of Pseudomonas fluorescens were found contaminating a biopesticide used in a previous study against Varroa destructor infestations in honey bee hives. In the aforementioned study the biopesticide, a formulation of the arthropod pathogen Beauveria bassiana, failed to have any impact on t...

  20. Bacterial Feeders, the Nematode Caenorhabditis elegans and the Flagellate Cercomonas longicauda, have different Effects on Outcome of Competition among the Pseudomonas Biocontrol Strains CHA0 and DSS73

    DEFF Research Database (Denmark)

    Pedersen, Annette; Nybroe, Ole; Winding, Anne

    2009-01-01

    selective feeding flagellate Cercomonas longicauda versus the non-selective feeding nematode Caenorhabditis elegans) influence the abundance of two bacteria that compete for resources in simple model communities. Microcosms consisted of either one gfp-tagged bacterial strain (Pseudomonas fluorescens DSM...

  1. E. coli bacteremia in comparison to K. pneumoniae bacteremia: influence of pathogen species and ESBL production on 7-day mortality

    Directory of Open Access Journals (Sweden)

    R. Leistner

    2016-10-01

    Full Text Available Abstract In a previous study, we demonstrated prolonged length of hospital stay in cases of extended-spectrum beta-lactamase (ESBL-positive K. pneumoniae bacteremia compared to bacteremia cases due to E. coli (ESBL-positive and –negative and ESBL-negative K. pneumoniae. The overall mortality was significantly higher in bacteremia cases resulting from ESBL-positive pathogens but also in K. pneumoniae cases disregarding ESBL-production. In order to examine whether pathogen species rather than multidrug resistance might affect mortality risk, we reanalyzed our dataset that includes 1.851 cases of bacteremia.

  2. Kinetics of Enantiomerically Enriched Synthesis of Solketal Esters Using Native and SBA-15 supported P. Fluorescens Lipase

    Directory of Open Access Journals (Sweden)

    Zniszczoł Aurelia

    2017-06-01

    Full Text Available The studies showed that alkaline lipase from Pseudomonas fluorescens enables an irreversible transesterification of vinyl esters to give enantiomeric excess (eeR of about 80% using vinyl butyrate as acyl donor and diisopropyl ether as a solvent, at partially optimized conditions. For the native lipase the process was adequately described by a five-parameter Ping-Pong Bi Bi model for both enantiomers plus expression accounting for the formation of enzyme-acyl donor complex, but for the same lipase supported on mesoporous materials of SBA-15-Oc type, R-product inhibition also had to be taken into account. The use of hydrophobic support increased by more than two-fold the rate of the S-solketal conversion but even more that of R-solketal. Thus the immobilization of lipase had very positive effect on the process kinetics but decreased its enantioselectivity.

  3. Campylobacter bacteremia: a rare and under-reported event?

    Science.gov (United States)

    Louwen, R.; van Baarlen, P.; van Vliet, A. H. M.; van Belkum, A.; Hays, J. P.; Endtz, H. P.

    2012-01-01

    Bacteria belonging to the species Campylobacter are the most common cause of bacterial diarrhoea in humans. The clinical phenotype associated with Campylobacter infections ranges from asymptomatic conditions to severe colitis and bacteremia. In susceptible patients, Campylobacter infections are associated with significant morbidity and mortality, with both host factors and bacterial factors being involved in the pathogenesis of bacteremia. In the host, age, gender and immune-compromising conditions may predispose for Campylobacter infections, whilst the most important bacterial determinants mentioned in the literature are cytotoxin production and flagellar motility. The role of sialylated lipo-oligosaccharide (LOS) and serum resistance in bacteremia is inconclusive at this time, and the clinical significance of Campylobacter bacteremia is not yet fully understood. More emphasis on the detection of Campylobacter species from blood cultures in susceptible patients at risk for Campylobacter infections will increase our understanding of the pathogenesis and the relevance of Campylobacter bacteremia. PMID:24611124

  4. Gardnerella vaginalis bacteremia in a premature neonate.

    Science.gov (United States)

    Amaya, Rene A; Al-Dossary, Fahad; Demmler, Gail J

    2002-01-01

    Gardnerella vaginalis is a normal component of the human vaginal flora and commonly associated with bacterial vaginosis. Invasive infection in obstetrical patients due to G. vaginalis has also been reported. In the pediatric age range, infection due to G. vaginalis is extremely rare and limited to neonates. We describe a 23-week premature infant with G. vaginalis bacteremia and review the characteristics of neonatal G. vaginalis infection reported in the literature. Antibiotic susceptibility testing of G. vaginalis isolates has shown that penicillin, ampicillin, erthromycin, clindamycin, and vancomycin are effective in vitro.

  5. Bacteremia with an Unusual Pathogen: Mycobacterium neoaurum

    Directory of Open Access Journals (Sweden)

    Hesham Awadh

    2016-01-01

    Full Text Available Mycobacterium neoaurum (M. neoaurum is an infrequently encountered cause of infection in humans. It is a member of the rapidly growing mycobacteria family. It predominately afflicts those with a compromised immune status and a chronically indwelling vascular access. Isolation of this organism is challenging yet the advent of 16s ribosomal sequencing paved the way for more sensitive detection. No treatment guidelines are available and treatment largely depends on the experience of the treating physician and nature of the isolate. We report a case of M. neoaurum bacteremia in an immune competent host, with a chronically placed peripherally inserted central catheter (PICC line.

  6. Bacteremia in connection with transurethral resection of the prostate

    DEFF Research Database (Denmark)

    Nielsen, P B; Hansen, R I; Madsen, O G

    1987-01-01

    A bacteriological survey of 50 consecutive patients undergoing transurethral resection of the prostate was performed. Preoperatively, 28% of the patients had asymptomatic bacteriuria. In the postoperative period, 46% of all the patients developed transient bacteremia. A significantly higher rate...... of bacteremia was found in patients with hypertrophy of the prostate than in those with cancer of the prostate and in patients undergoing long-lasting surgical intervention. Patients who developed bacteremia due to pathogenic bacteria were hospitalized for a significantly longer period of time....

  7. Effects of atmospheric conditions on ice nucleation activity of Pseudomonas

    Directory of Open Access Journals (Sweden)

    C. Glaux

    2012-11-01

    Full Text Available Although ice nuclei from bacterial origin are known to be efficient at the highest temperatures known for ice catalysts, quantitative data are still needed to assess their role in cloud processes. Here we studied the effects of three typical cloud conditions (i acidic pH (ii NO2 and O3 exposure and (iii UV-A exposure on the ice nucleation activity (INA of four Pseudomonas strains. Three of the Pseudomonas syringae strains were isolated from cloud water and the phyllosphere and Pseudomonas fluorescens strain CGina-01 was isolated from Antarctic glacier ice melt. Among the three conditions tested, acidic pH caused the most significant effects on INA likely due to denaturation of the ice nucleation protein complex. Exposure to NO2 and O3 gases had no significant or only weak effects on the INA of two P. syringae strains whereas the INA of P. fluorescens CGina-01 was significantly affected. The INA of the third P. syringae strain showed variable responses to NO2 and O3 exposure. These differences in the INA of different Pseudomonas suggest that the response to atmospheric conditions could be strain-specific. After UV-A exposure, a substantial loss of viability of all four strains was observed whereas their INA decreased only slightly. This corroborates the notion that under certain conditions dead bacterial cells can maintain their INA. Overall, the negative effects of the three environmental factors on INA were more significant at the warmer temperatures. Our results suggest that in clouds where temperatures are near 0 °C, the importance of bacterial ice nucleation in precipitation processes could be reduced by some environmental factors.

  8. Raoultella Planticola Bacteremia Following Consumption of Seafood

    Directory of Open Access Journals (Sweden)

    Philip W Lam

    2014-01-01

    Full Text Available Raoultella planticola is a Gram-negative bacillus commonly found in water, soil and aquatic environments. There have only been 16 cases of R planticola infection documented in the literature to date. R planticola possesses the ability to convert histidine to histamine and can produce symptoms of scombroid poisoning when poorly prepared seafood is consumed in large amounts. The present report describes a case involving a 56-year-old woman who presented with R planticola bacteremia and symptoms consistent with cholangitis four days after consuming a seafood salad containing squid and octopus. She was successfully treated with intravenous ceftriaxone followed by oral ciprofloxacin. Recent chemotherapy, proton pump inhibitor use and altered biliary flow secondary to hepatic metastases may have been contributing factors to the pathogenesis of disease.

  9. Cellulitis and Bacteremia Caused by Bergeyella zoohelcum

    Directory of Open Access Journals (Sweden)

    Wei-Ru Lin

    2007-01-01

    Full Text Available Bergeyella zoohelcum is a rod-shaped, aerobic, Gram-negative, non-motile and non-saccharolytic bacterium. It is frequently isolated from the upper respiratory tract of dogs, cats and other mammals. Clinically, B. zoohelcum has been known to cause cellulitis, leg abscess, tenosynovitis, septicemia, pneumonia and meningitis, and is associated with animal bites. In addition, food-borne transmission was considered in a recent case report. We report a 73-year-old man with liver cirrhosis who had no history of dog bite but had dog exposure, who developed cellulitis of the left lower leg and B. zoohelcum was isolated from blood culture. This patient, without evidence of polymicrobial infection, was treated with cefazolin and gentamicin with a good outcome. B. zoohelcum is a zoonotic pathogen that may cause bacteremia in patients with underlying disease such as liver cirrhosis; it can be treated with a beta-lactam or quinolone.

  10. Cytokinin production by Pseudomonas fluorescens G20-18 determines biocontrol activity against Pseudomonas syringae in Arabidopsis

    Czech Academy of Sciences Publication Activity Database

    Grosskinsky, D. K.; Tafner, R.; Moreno, M. V.; Stenglein, S. A.; Garcia de Salamone, I. E.; Nelson, L. M.; Novák, Ondřej; Strnad, Miroslav; van der Graaff, E.; Roitsch, Thomas

    2016-01-01

    Roč. 6, MAR 17 (2016), s. 23310 ISSN 2045-2322 R&D Projects: GA MŠk(CZ) LO1204; GA ČR GA15-22322S; GA MŠk(CZ) LO1415 Institutional support: RVO:61389030 ; RVO:67179843 Keywords : GROWTH-PROMOTING RHIZOBACTERIA * PLANT -GROWTH * SALICYLIC-ACID Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.259, year: 2016

  11. Anti-pseudomona and Anti-bacilli Activity of Some Medicinal Plants of Iran

    Directory of Open Access Journals (Sweden)

    Gholam Hosein Shahidi Bonjar

    2003-10-01

    Full Text Available The use of plants in treatment of burns, dermatophytes, and infectious diseases is common in traditional medicine of Iran. Based on ethno pharmacological and taxonomic information, antibacterial activities of methanol extracts of some medicinal plants of Iran were determined by In Vitro bioassays using agar diffusion-method against standard strains of Pseudomonas aeruginosa, P. fluorescens, Bacillus subtilis, B. cereus and B. pumilis at 20 mg/ml. From 180 plant species of 72 families, 78 species (43.3% in 42 families (58.3% showed antibacterial activities against B. cereus (88.4%, B. subtilis (39.7%, B. pumilis (37.1%, P. fluorescens (37.1% and P. aeruginos (10.2%. The most active plant families were Apiaceae, Compositae and Labiatae with 9, 8 and 7 active plant species respectively. Minimum inhibitory concentrations (MIC of the active plants were determined using two fold serial dilutions. Most active plant against Bacilli was Myrtus communis L. with MIC of 1.87 mg/ml. For Pseudomonas species, Dianthus caryophyllus L. and Terminalia chebula (Gaertner Retz. were more active with the MIC of 0.46 mg/ml for P. fluorescens and of 1.87 mg/ml for P. aeruginosa respectively.

  12. OXA-48-Producing Enterobacteriaceae Causing Bacteremia, United Arab Emirates

    Directory of Open Access Journals (Sweden)

    Chulsoo Ahn

    2015-01-01

    Full Text Available OXA-48-producing isolates were identified in approximately 4% and less than 1% of ESBL-producing and non-ESBL-producing E. coli and K. pneumoniae causing bacteremia at the largest tertiary hospital in Abu Dhabi.

  13. Bacteremia causes hippocampal apoptosis in experimental pneumococcal meningitis

    DEFF Research Database (Denmark)

    Andersen, Christian Østergaard; Leib, S.L.; Rowland, Ian J

    2010-01-01

    by antibody treatment resulted in significantly reduced apoptosis (0.08 (0.02-0.20), P=0.01) as compared to meningitis. CONCLUSIONS: Our results demonstrate that bacteremia accompanying meningitis plays an important role in the development of hippocampal injury in pneumococcal meningitis.......ABSTRACT: BACKGROUND: Bacteremia and systemic complications both play important roles in brain pathophysiological alterations and the outcome of pneumococcal meningitis. Their individual contributions to the development of brain damage, however, still remain to be defined. METHODS: Using an adult...... rat pneumococcal meningitis model, the impact of bacteremia accompanying meningitis on the development of hippocampal injury was studied. The study comprised of the three groups: I. Meningitis (n=11), II. meningitis with attenuated bacteremia resulting from iv injection of serotype...

  14. Impact of bacteremia on the pathogenesis of experimental pneumococcal meningitis

    DEFF Research Database (Denmark)

    Brandt, Christian; Peters, David Alberg; Liptrot, Matthew George

    2008-01-01

    Background. Bacteremia plays a major role in the outcome of pneumococcal meningitis. This experimental study investigated how bacteremia influences the pathophysiologic profile of the brain. Methods. Rats with Streptococcus pneumoniae meningitis were randomized to 1 of 3 groups of infected study...... rats: (1) rats with attenuated bacteremia resulting from intravenous injection of serotype-specific pneumococcal antibody, (2) rats with early-onset bacteremia resulting from concomitant intravenous infection, or (3) a meningitis control group. The blood-brain barrier (BBB) breakdown, ventricle size......, brain water distribution, and brain pathologic findings were analyzed using magnetic resonance morphological and functional imaging. Laboratory data and clinical disease scores were obtained. Results. Attenuation of the bacteremic component of pneumococcal meningitis improved clinical disease symptoms...

  15. Bacteremia due to Acinetobacter ursingii in infants: Reports of two ...

    African Journals Online (AJOL)

    Bacteremia due to Acinetobacter ursingii in infants: Reports of two cases. Nurhayat Yakut, Eda Kadayifci Kepenekli, Ayse Karaaslan, Serkan Atici, Gulsen Akkoc, Sevliya Ocal Demir, Ahmet Soysal, Mustafa Bakir ...

  16. Campylobacter bacteremia: A rare and under-reported event?

    NARCIS (Netherlands)

    Louwen, R.; Baarlen, van P.; Vliet, van A.H.M.; Belkum, van A.; Hays, J.P.; Endtz, H.P.

    2012-01-01

    Bacteria belonging to the species Campylobacter are the most common cause of bacterial diarrhoea in humans. The clinical phenotype associated with Campylobacter infections ranges from asymptomatic conditions to severe colitis and bacteremia. In susceptible patients, Campylobacter infections are

  17. Risk factors for mortality in patients with Serratia marcescens bacteremia.

    Science.gov (United States)

    Kim, Sun Bean; Jeon, Yong Duk; Kim, Jung Ho; Kim, Jae Kyoung; Ann, Hea Won; Choi, Heun; Kim, Min Hyung; Song, Je Eun; Ahn, Jin Young; Jeong, Su Jin; Ku, Nam Su; Han, Sang Hoon; Choi, Jun Yong; Song, Young Goo; Kim, June Myung

    2015-03-01

    Over the last 30 years, Serratia marcescens (S. marcescens) has emerged as an important pathogen, and a common cause of nosocomial infections. The aim of this study was to identify risk factors associated with mortality in patients with S. marcescens bacteremia. We performed a retrospective cohort study of 98 patients who had one or more blood cultures positive for S. marcescens between January 2006 and December 2012 in a tertiary care hospital in Seoul, South Korea. Multiple risk factors were compared with association with 28-day all-cause mortality. The 28-day mortality was 22.4% (22/98 episodes). In a univariate analysis, the onset of bacteremia during the intensive care unit stay (p=0.020), serum albumin level (p=0.011), serum C-reactive protein level (p=0.041), presence of indwelling urinary catheter (p=0.023), and Sequential Oran Failure Assessment (SOFA) score at the onset of bacteremia (pmarcescens bacteremia.

  18. Group B Streptococcal Colonization and Bacteremia in Rabbits

    Directory of Open Access Journals (Sweden)

    Arda Lembet

    1997-01-01

    Full Text Available Objective: We evaluated the effect of maternal administration of ampicillin/sulbactam on colonization and bacteremia in newborn rabbits after intracervical inoculation of mothers with group B streptococci (GBS.

  19. Evaluation of the incidence of bacteremia following middle ear operations

    OpenAIRE

    Mohammad Naeimi; Kiarash Ghazvini K; Mohammad Taghi Shakeri MT; Merangiz Kaboli; Mahmood Bagheri

    2009-01-01

    Introduction: Bacteremia following middle ear surgeries occurs in a significant number of patients. The aim of this study is to investigate the incidence of bacteremia following middle ear surgeries. Materials and Methods: Sixty two patients who where candidates for middle ear operation were enrolled in this study. Blood samples were obtained from each patient immediately before and after operation for bacteriologic analysis. Demographic and middle ear disease characteristics were also record...

  20. Pulmonary infiltrates during community acquired Gram-negative bacteremia

    DEFF Research Database (Denmark)

    Fjeldsøe-Nielsen, Hans; Gjeraa, Kirsten; Berthelsen, Birgitte G

    2013-01-01

    The primary aim of this study was to describe the frequency of pulmonary infiltrates on chest X-ray (CXR) during community acquired Gram-negative bacteremia at a single centre in Denmark.......The primary aim of this study was to describe the frequency of pulmonary infiltrates on chest X-ray (CXR) during community acquired Gram-negative bacteremia at a single centre in Denmark....

  1. Comparison between bacteremia caused by Acinetobacter pittii and Acinetobacter nosocomialis.

    Science.gov (United States)

    Liu, Yuag-Meng; Lee, Yi-Tzu; Kuo, Shu-Chen; Chen, Te-Li; Liu, Chang-Pan; Liu, Chun-Eng

    2017-02-01

    Patients with Acinetobacter pittii and Acinetobacter nosocomialis bacteremia have lower mortality rates than those with Acinetobacter baumannii bacteremia. However, it is unknown whether these organisms differ in outcomes of bacteremic patients. We conducted this study to answer this question. In this retrospective study conducted at a teaching hospital in Taiwan, we enrolled all 86 patients who had developed A. pittii bacteremia and those with A. nosocomialis bacteremia from 2000 to 2008 while matching for age, sex, Acute Physiology and Chronic Health Evaluation II score, and appropriate antimicrobial therapy. After adjustment, we accessed the clinical characteristics and 14- and 28-day mortalities. We found that the patients with A. pittii bacteremia had multiple comorbidities less often and received invasive procedures less frequently. The 14-day mortality rate of patients with A. pittii or A. nosocomialis bacteremia was 14% and 7%, respectively, whereas their 28-day mortality rate was 17% and 9%, respectively. Using the mortality rate in patients with A. nosocomialis bacteremia as a reference, the odds ratios for the 14- and 28-day crude morality in those with A. pittii were 2.16 [95% confidence interval (CI), 0.77-6.05] and 2.06 (95% CI, 0.82-5.15), respectively, whereas the adjusted odds ratios for 14- and 28-day mortality were 1.89 (95% CI, 0.56-6.14) and 1.67 (95% CI, 0.59-4.78) respectively. Our 8-year study showed that the mortality rate of A. pittii bacteremia was higher but the difference was not statistically significant. Copyright © 2015. Published by Elsevier B.V.

  2. Enterobacteriaceae bacteremias among cancer patients: an observational cohort study

    Science.gov (United States)

    Henao-Martínez, Andrés F.; González-Fontal, Guido R.; Castillo-Mancilla, José R.; Yang, Ivana V.

    2013-01-01

    Summary Background Enterobacteriaceae bacteremia is a common complication in patients with neoplasm. The cancer itself, chemotherapy-induced immunosuppression, and other cancer-related procedures play a role as predisposing factors for this condition. However, despite the clear association between cancer and Enterobacteriaceae bacteremia, the distinctive clinical characteristics of patients with cancer presenting with Enterobacteriaceae bacteremia have not been well established. Methods The population studied was a prospective cohort of adult hospitalized patients with Enterobacteriaceae bacteremia in a tertiary care hospital. We compared the clinical variables and microbiological features between patients with an underlying neoplasm (n = 203) and those without (n = 259). STATA software was used for statistical association analysis. Results In a bivariate analysis, older age, prior exposure to aminopenicillins, fewer days of symptoms, biliary source of bacteremia, greater severity of APACHE II score, lower white blood cell and platelet counts, and the presence of Klebsiella pneumoniae were more common in the neoplasm group. In a multivariable analysis, K. pneumoniae bacteremia (odds ratio (OR) 6.13, 95% confidence interval (CI) 1.65–22.71; p = 0.007), APACHE II score (OR 1.18, 95% CI 1.05–1.34; p = 0.007), and exposure to aminopenicillins (OR 28.84, 95% CI 1.94–429.3; p = 0.015) were associated with neoplasm. K. pneumoniae bacteremia was more commonly present in patients with lung and gastrointestinal cancers. Conclusions We have confirmed the association of K. pneumoniae bacteremia with underlying neoplastic disease, especially with gastrointestinal malignancies, which may allow stratification for initial empiric antibiotic therapy in this subset of patients. Prior exposure to aminopenicillins in the neoplasm group might contribute to this finding. PMID:23313157

  3. Bacteremia with Bacteroides pyogenes after a cat bite

    DEFF Research Database (Denmark)

    Madsen, Ida Ringsborg; Justesen, Ulrik Stenz

    2011-01-01

    Animal bite wounds are often infected with bacteria from the animal's oral flora. We report what we believe to be the first case of bacteremia with Bacteroides pyogenes resulting from an infected cat bite.......Animal bite wounds are often infected with bacteria from the animal's oral flora. We report what we believe to be the first case of bacteremia with Bacteroides pyogenes resulting from an infected cat bite....

  4. Community-Acquired urinary tract infection by pseudomonas oryzihabitans

    Directory of Open Access Journals (Sweden)

    Sunita M Bhatawadekar

    2013-01-01

    Full Text Available Pseudomonas oryzihabitans and Chrysomonas luteola has been placed in CDC group Ve2 and Ve1 respectively. These bacteria appear to be emerging pathogens. P. oryzihabitans was isolated from cases of bacteremia, CNS infections, wound infections, peritonitis, sinusitis, catheter associated infections in AIDS patient, and pneumonia. Most of the reports of P. oryzihabitans infection were of nosocomial origin in individuals with some predisposing factors. We report here a case of community acquired UTI by P. oryzihabitans in an immune-competent patient with stricture of urethra.

  5. Impact of Medium on the Development and Physiology of Pseudomonas fluorescens Biofilms on Polyurethane Paint

    Science.gov (United States)

    2012-02-01

    contribute to the degradation of those coatings. Specifically, we characterized how medium conditions and substrate composition contribute to growth of...interfaces (Brown et al. 2010; Branda et al. 2005). Pseudomonad bacteria have been shown to be common constituents of aviation fuel microbiota in...These results demonstrate that medium composition impacts both the biofilm and cell populations, but not in the same way. In addition, carbon is

  6. 76 FR 52871 - Pseudomonas fluorescens Strain CL145A; Exemption From the Requirement of a Tolerance

    Science.gov (United States)

    2011-08-24

    ... with plants, including those food plants consumed raw. The Manual of Clinical Microbiology (8th edition... a joint U.N. Food and Agriculture Organization/World Health Organization food standards program, and...

  7. Heterologous Expression of a Chitinase Gene From Aeromonas Caviaein Pseudomonas Fluorescens

    OpenAIRE

    Suwanto, Antonius; Malik, Amarila; TJAHJONO, BUDI; Harling, Rob

    2003-01-01

    A transcriptional fusion for an Aeromonas caviae chitinase gene was constructed under the control of a constitutive promoter of the kanaraycin resistance gene (PKmR). The construct was inserted into a medium copy number broad host range plasmid vector to yield recombinant plasmid pAM340, which harbored transcriptional fusion PKmR- chi. Another transcriptional fusion, Ptac-chi, in a recombinant plasmid pAM630, was conducted as comparison. Triparental mating of E. coli carrying the recombinant...

  8. HETEROLOGOUS EXPRESSION OF A CHITINASE GENE FROM AEROMONAS CAVIAEIN PSEUDOMONAS FLUORESCENS

    OpenAIRE

    ANTONIUS SUWANTO; AMARILA MAHK; BUDI TJAHJONO

    2003-01-01

    A transcriptional fusion for an Aeromonas caviae chitinase gene was constructed under the control of a constitutive promoter of the kanaraycin resistance gene (PKmR). The construct was inserted into a medium copy number broad host range plasmid vector to yield recombinant plasmid pAM340, which harbored transcriptional fusion PKmR- chi. Another transcriptional fusion, Ptac-chi, in a recombinant plasmid pAM630, was conducted as comparison. Triparental mating of E. coli carrying the recom...

  9. Lipopeptide biosurfactant viscosin enhances dispersal of Pseudomonas fluorescens SBW25 biofilms

    DEFF Research Database (Denmark)

    Bonnichsen, Lise; Svenningsen, Nanna Bygvraa; Rybtke, Morten Levin

    2015-01-01

    Pseudomonads produce several lipopeptide biosurfactants that have antimicrobial properties but that also facilitate surface motility and influence biofilm formation. Detailed studies addressing the significance of lipopeptides for biofilm formation and architecture are rare. Hence, the present st...

  10. The effect of phylogenetically different bacteria on the fitness of Pseudomonas fluorescens in sand microcosms

    NARCIS (Netherlands)

    Tyc, Olaf; Wolf, Alexandra; Garbeva, Paolina

    2015-01-01

    n most environments many microorganisms live in close vicinity and can interact in various ways. Recent studies suggest that bacteria are able to sense and respond to the presence of neighbouring bacteria in the environment and alter their response accordingly. This ability might be an important

  11. Pseudomonas spp. ISOLATED FROM THE ORAL CAVITY OF HEALTHCARE WORKERS FROM AN ONCOLOGY HOSPITAL IN MIDWESTERN BRAZIL

    Science.gov (United States)

    LIMA, Ana Beatriz Mori; LEÃO-VASCONCELOS, Lara Stefânia Netto de Oliveira; COSTA, Dayane de Melo; VILEFORT, Larissa Oliveira Rocha; ANDRÉ, Maria Cláudia Dantas Porfírio Borges; BARBOSA, Maria Alves; PRADO-PALOS, Marinésia Aparecida

    2015-01-01

    This cross-sectional study, performed in an oncology hospital in Goiania, aimed to characterize the prevalence of oral colonization and antimicrobial susceptibility of Pseudomonas spp. isolated from the saliva of healthcare workers. Microorganisms were subjected to biochemical tests, susceptibility profile, and phenotypic detection. Of 76 participants colonized with Gram negative bacilli, 12 (15.8%) harbored Pseudomonas spp. Of all isolates, P. aeruginosa (75.0%), P. stutzeri (16.7%), and P. fluorescens (8.3%), were resistant to cefoxitin, and therefore likely to be AmpC producers. The results are clinically relevant and emphasize the importance of surveillance to minimize bacterial dissemination and multiresistance. PMID:27049706

  12. Acinetobacter spp. are associated with a higher mortality in intensive care patients with bacteremia: a survival analysis.

    Science.gov (United States)

    Leão, Aline C Q; Menezes, Paulo R; Oliveira, Maura S; Levin, Anna S

    2016-08-09

    It has been challenging to determine the true clinical impact of Acinetobacter spp., due to the predilection of this pathogen to colonize and infect critically ill patients, who often have a poor prognosis. The aim of this study was to assess whether Acinetobacter spp. bacteremia is associated with lower survival compared with bacteremia caused by other pathogens in critically ill patients. This study was performed at Hospital das Clínicas, University of São Paulo, Brazil. There are 12 intensive care units (ICUs) in the hospital: five Internal Medicine ICUs (emergency, nephrology, infectious diseases and respiratory critical care), three surgical ICU (for general surgery and liver transplantion), an Emergency Department ICU for trauma patients, an ICU for burned patients, a neurosurgical ICU and a post-operative ICU. A retrospective review of medical records was conducted for all patients admitted to any of the ICUs, who developed bacteremia from January 2010 through December 2011. Patients with Acinetobacter spp. were compared with those with other pathogens (Klebsiella pneumoniae, Staphylococcus aureus, Enterobacter spp., Enterococcus spp., Pseudomonas aeruginosa). We did a 30-day survival analysis. The Kaplan-Meier method and log-rank test were used to determine the overall survival. Potential prognostic factors were identified by bivariate and multivariate Cox regression analysis. One hundred forty-one patients were evaluated. No differences between patients with Acinetobacter spp. and other pathogens were observed with regard to age, sex, APACHE II score, Charlson Comorbidity Score and type of infection. Initial inappropriate antimicrobial treatment was more frequent in Acinetobacter bacteremia (88 % vs 51 %). Bivariate analysis showed that age > 60 years, diabetes mellitus, and Acinetobacter spp. infection were significantly associated with a poor prognosis. Multivariate model showed that Acinetobacter spp. infection (HR = 1.93, 95 % CI: 1

  13. Prevalence of bacteremia in dairy cattle with acute puerperal metritis.

    Science.gov (United States)

    Credille, B C; Woolums, A R; Giguère, S; Robertson, T; Overton, M W; Hurley, D J

    2014-01-01

    Acute puerperal metritis (APM) affects 30% of postpartum dairy cattle. Bacteremia negatively impacts survival in cattle with coliform mastitis. However, the prevalence of bacteremia in dairy cattle with APM is unknown. Bacteremia is detectable in a large proportion of cattle with APM. Seventeen dairy cows with APM and 17 healthy dairy cattle. Prospective case-control study. Cases were identified by daily monitoring of cattle in the first 10 days after calving. Controls were matched to cases by parity and days in milk. Cows were examined at the time of identification of APM. A complete blood count, serum biochemical analysis, and bacteriologic culture of blood and lochial fluid were performed on each animal at the time of diagnosis. The same samples were collected from healthy herdmates of a similar parity and days in milk. Blood culture results and clinicopathologic variables were compared between groups. Conditional logistic regression was used to evaluate factors associated with APM, whereas multivariate logistic regression was used to evaluate factors associated with bacteremia. Bacteremia occurred in 53% (9/17) of cattle with APM and 53% (8/15) controls. Bacillus spp. was the organism most commonly isolated from the bloodstream in cattle of both groups. Bacteremic cattle in both groups were significantly less likely to have basophils in the peripheral circulation (P = .02) and more likely to have higher serum globulin concentrations (P = .02). Bacteremia is a common occurrence in postpartum dairy cattle. Further study is warranted to investigate the modes by which bacteria colonize the bloodstream in this population of animals and the importance of bacteremia on health and productivity of affected animals. Copyright © 2014 by the American College of Veterinary Internal Medicine.

  14. Pseudomonas aeruginosa in Healthcare Settings

    Science.gov (United States)

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

  15. Predictors of Mortality in Staphylococcus aureus Bacteremia

    Science.gov (United States)

    Jensen, Slade O.; Vaska, Vikram L.; Espedido, Björn A.; Paterson, David L.; Gosbell, Iain B.

    2012-01-01

    Summary: Staphylococcus aureus bacteremia (SAB) is an important infection with an incidence rate ranging from 20 to 50 cases/100,000 population per year. Between 10% and 30% of these patients will die from SAB. Comparatively, this accounts for a greater number of deaths than for AIDS, tuberculosis, and viral hepatitis combined. Multiple factors influence outcomes for SAB patients. The most consistent predictor of mortality is age, with older patients being twice as likely to die. Except for the presence of comorbidities, the impacts of other host factors, including gender, ethnicity, socioeconomic status, and immune status, are unclear. Pathogen-host interactions, especially the presence of shock and the source of SAB, are strong predictors of outcomes. Although antibiotic resistance may be associated with increased mortality, questions remain as to whether this reflects pathogen-specific factors or poorer responses to antibiotic therapy, namely, vancomycin. Optimal management relies on starting appropriate antibiotics in a timely fashion, resulting in improved outcomes for certain patient subgroups. The roles of surgery and infectious disease consultations require further study. Although the rate of mortality from SAB is declining, it remains high. Future international collaborative studies are required to tease out the relative contributions of various factors to mortality, which would enable the optimization of SAB management and patient outcomes. PMID:22491776

  16. Staphylococcus epidermidis as a cause of bacteremia.

    Science.gov (United States)

    Kleinschmidt, Sharon; Huygens, Flavia; Faoagali, Joan; Rathnayake, Irani U; Hafner, Louise M

    2015-01-01

    Staphylococcus epidermidis is a biofilm-producing commensal organism found ubiquitously on human skin and mucous membranes, as well as on animals and in the environment. Biofilm formation enables this organism to evade the host immune system. Colonization of percutaneous devices or implanted medical devices allows bacteria access to the bloodstream. Isolation of this organism from blood cultures may represent either contamination during the blood collection procedure or true bacteremia. S. epidermidis bloodstream infections may be indolent compared with other bacteria. Isolation of S. epidermidis from a blood culture may present a management quandary for clinicians. Over-treatment may lead to patient harm and increases in healthcare costs. There are numerous reports indicating the difficulty of predicting clinical infection in patients with positive blood cultures with this organism. No reliable phenotypic or genotypic algorithms currently exist to predict the pathogenicity of a S. epidermidis bloodstream infection. This review will discuss the latest advances in identification methods, global population structure, pathogenicity, biofilm formation, antimicrobial resistance and clinical significance of the detection of S. epidermidis in blood cultures. Previous studies that have attempted to discriminate between invasive and contaminating strains of S. epidermidis in blood cultures will be analyzed.

  17. Diabetes does not affect outcome in patients with Enterobacteriaceae bacteremia

    Directory of Open Access Journals (Sweden)

    Peralta Galo

    2009-06-01

    Full Text Available Abstract Background There is limited information about the effect of diabetes on the prognosis of patients with bacterial infections. We performed a retrospective cohort study to investigate possible correlations between diabetes and prognosis in patients with Enterobacteriaceae bacteremia. Methods We reviewed the medical charts of 1112 patients who were treated at a community teaching hospital for Enterobacteriaceae bacteremia from January 1997 through June 2007. Factors associated with in-hospital mortality were analyzed by logistic regression analysis. Results Among the 1112 patients with Enterobacteriaceae bacteremia, 181 (16.3% were diabetic patients; 90 patients (8.1% died while in the hospital. Compared to non-diabetic patients, diabetic patients were older (75.4 ± 11.9 years vs. 70 ± 16.6 years, p p = 0.39]. In a multivariate analysis, the variables associated with in-hospital mortality were age, the origin of the bacteremia, and the presence of immunosuppression. Diabetes was not associated with outcome. Conclusion In this cohort of patients with Enterobacteriaceae bacteremia, diabetes was not associated with a poorer prognosis.

  18. Bacteremia during adenoidectomy: a comparison of suction diathermy adenoid ablation and adenoid curettage.

    LENUS (Irish Health Repository)

    Casserly, Paula

    2010-08-01

    Transient bacteremia is induced by adenoidectomy when the integrity of the nasopharyngeal membrane is broken. The aim of this study was to determine the incidence of bacteremia in patients undergoing adenoidectomy, to identify the causative organisms, and to compare the incidences of bacteremia between the two techniques suction diathermy and curettage.

  19. Predominant association of Raoultella bacteremia with diseases of the biliary tract

    NARCIS (Netherlands)

    Jong, Eefje de; Erkens-Hulshof, S.; Velden, L.B. van der; Voss, A.; Bosboom, R.; Hodiamont, C.J.; Wever, P.C.; Rentenaar, R.J.; Sturm, P.D.J.

    2014-01-01

    A case series of 14 patients with Raoultella bacteremia was compared with 28 Klebsiella oxytoca and 28 Klebsiella pneumoniae bacteremia cases. Forty-three percent of Raoultella bacteremia cases were associated with biliary tract disease, compared to 32% and 22% of patients with K. oxytoca and K.

  20. Predominant association of Raoultella bacteremia with diseases of the biliary tract

    NARCIS (Netherlands)

    de Jong, Eefje; Erkens-Hulshof, Sandra; van der Velden, Lieven B. J.; Voss, Andreas; Bosboom, Ron; Hodiamont, Caspar J.; Wever, Peter C.; Rentenaar, Rob J.; Sturm, Patrick D.

    2014-01-01

    Abstract A case series of 14 patients with Raoultella bacteremia was compared with 28 Klebsiella oxytoca and 28 Klebsiella pneumoniae bacteremia cases. Forty-three percent of Raoultella bacteremia cases were associated with biliary tract disease, compared to 32% and 22% of patients with K. oxytoca

  1. Bacteremia is associated with excess long-term mortality

    DEFF Research Database (Denmark)

    Nielsen, Stig Lønberg; Lassen, Annmarie Touborg; Gradel, Kim Oren

    2015-01-01

    of birth, residency and calendar time, in Denmark during 2000-2008. We calculated absolute mortality and adjusted mortality rate ratios (MRRs) in predefined follow-up periods. RESULTS: The absolute mortality for bacteremia patients (n = 7783) and population controls (n = 38,906) was 22.0% vs. 0.2% (30 days......), 41.4% vs. 2.6% (1 year) and 75.8% vs. 36.6% (10 years). For bacteremia patients, the MRR was 115.3 (95% CI, 88.2-150.9) 0-30 days after bacteremia and 2.1 (95% CI, 1.8-2.3) from 5 years to end of follow-up. The most common causes of death were cancer and cardiovascular diseases. Within one year...

  2. Incidence of bacteremia in cirrhotic patients undergoing upper endoscopic ultrasonography.

    Science.gov (United States)

    Fernández-Esparrach, Gloria; Sendino, Oriol; Araujo, Isis; Pellisé, Maria; Almela, Manel; González-Suárez, Begoña; López-Cerón, María; Córdova, Henry; Sanabria, Erwin; Uchima, Hugo; Llach, Josep; Ginès, Àngels

    2014-01-01

    The incidence of bacteremia after endoscopic ultrasonography (EUS) or EUS-guided fine-needle aspiration (EUS-FNA) is between 0% and 4%, but there are no data on this topic in cirrhotic patients. To prospectively assess the incidence of bacteremia in cirrhotic patients undergoing EUS and EUS-FNA. We enrolled 41 cirrhotic patients. Of these, 16 (39%) also underwent EUS-FNA. Blood cultures were obtained before and at 5 and 30 min after the procedure. When EUS-FNA was used, an extra blood culture was obtained after the conclusion of radial EUS and before the introduction of the sectorial echoendoscope. All patients were clinically followed up for 7 days for signs of infection. Blood cultures were positive in 16 patients. In 10 patients, blood cultures grew coagulase-negative Staphylococcus, Corynebacterium species, Propionibacterium species or Acinetobacterium Lwoffii, which were considered contaminants (contamination rate 9.8%, 95% CI: 5.7-16%). The remaining 6 patients had true positive blood cultures and were considered to have had true bacteremia (15%, 95% CI: 4-26%). Blood cultures were positive after diagnostic EUS in five patients but were positive after EUS-FNA in only one patient. Thus, the frequency of bacteremia after EUS and EUS-FNA was 12% and 6%, respectively (95% CI: 2-22% and 0.2-30%, respectively). Only one of the patients who developed bacteremia after EUS had a self-limiting fever with no other signs of infection. Asymptomatic Gram-positive bacteremia developed in cirrhotic patients after EUS and EUS-FNA at a rate higher than in non-cirrhotic patients. However, this finding was not associated with any clinically significant infections. Copyright © 2013 Elsevier España, S.L. and AEEH y AEG. All rights reserved.

  3. Peripartum bacteremia in the era of group B streptococcus prophylaxis.

    Science.gov (United States)

    Cape, Alison; Tuomala, Ruth E; Taylor, Chirisse; Puopolo, Karen M

    2013-04-01

    To define the microbial epidemiology and clinical risk factors associated with peripartum bacteremia in the era of group B streptococcus prophylaxis. We identified all cases of maternal bacteremia occurring during the peripartum time period (defined as from 7 days before delivery until 30 days after delivery) in a large maternity center from 2000 to 2008. Chart review was performed to determine the clinical factors associated with bacteremia. During the study period, blood cultures were obtained from 1,295 febrile peripartum women (1.6% of all parturients); 172 of 1,295 febrile peripartum women (13.3%) had bacteremia (2.2 cases per 1,000 deliveries) with 194 microbial isolates and 1 yeast. The most frequent bacterial isolates were Escherichia coli (35.9%), enterococci (23.6%), and anaerobic species (9.2%); group B streptococcus was isolated in only eight cases (4.1%). Clinical diagnoses among infected women included endometritis (56%), chorioamnionitis (21%), and urosepsis (8%). Among women with endometritis, 77% underwent cesarean delivery (compared with vaginal delivery; relative risk [RR] 10.85, 95% confidence interval [CI] 6.75-17.45) and 39% delivered at less than 37 weeks of gestation (compared with 37 weeks or more; RR 3.21, 95% CI 2.42-4.25). Severe maternal complications of bacteremia were noted; six women required intensive care unit admission, five women had development of ileus, and one death occurred because of urosepsis. In the era of group B streptococcus prophylaxis, E coli and enterococci are the most frequent bacteria isolated in peripartum bacteremia. Group B streptococcus accounted for only 4% of cases. III.

  4. Clinical and microbiological features of bacteremia caused by Enterococcus faecalis.

    Science.gov (United States)

    Ceci, Mónica; Delpech, Gastón; Sparo, Mónica; Mezzina, Vito; Sánchez Bruni, Sergio; Baldaccini, Beatriz

    2015-11-30

    Enterococcus faecalis is a frequent etiologic agent of invasive infections in hospitalized patients. The aim of this study was to analyze clinical and microbiological features of bacteremia caused by E. faecalis. Between 2011 and 2013, significant bacteremia caused by E. faecalis in hospitalized patients was studied. Patient characteristics, comorbid conditions, and 14-day mortality were recorded. Virulence genes esp, gelE, and cylA; opsonophagocytosis resistance; resistance to bactericidal effect of normal serum; beta lactamase production; and susceptibility to ampicillin, vancomycin, teicoplanin, gentamicin, and streptomycin were investigated. E. faecalis strains were recovered from 33 bacteremic patients. Polymicrobial bacteremia was diagnosed in 2 patients; 10 patients died. Virulence genes were found in strains from both deceased patients and survivors. Sources of bacteremia included urinary tract infections (36.4%), vascular catheters (15.1%), abscesses (9.1%), and unknown (48.5%). Underlying diseases included cancer (30.3%), diabetes (36.4%), cirrhosis (6.1%), renal (36.4%), and chronic obstructive pulmonary disease (2.0%). Co-morbidities included alcohol use (26.1%); glucocorticoid therapy (19.0%); prior antibiotic therapy (60.6%); and central venous (21.2%), arterial (12.1%), and urinary (63.6%) catheters. Also, 57.6% of patients came from the intensive care unit (ICU); 33.3% had mechanical ventilation. Significant mortality-associated conditions included polymicrobial bacteremia, oncological disease, APACHE II score ≤ 20, ICU stay, renal disease, central venous catheter, and mechanical ventilation. Outcome of patients was associated with their status and not with the presence of virulence genes in E. faecalis strains. A significant percentage of bacteremia had undetermined origin. An alternate origin may be the gastrointestinal tract, through translocation.

  5. Shewanella alga bacteremia in two patients with lower leg ulcers

    DEFF Research Database (Denmark)

    Domínguez, H.; Vogel, Birte Fonnesbech; Gram, Lone

    1996-01-01

    The first Danish cases of Shewanella alga bacteremia in two patients with chronic lower leg ulcers are reported. Both patients were admitted to the hospital during the same month of a very warm summer and had been exposed to the same marine environment, thereby suggesting the same source of infec......The first Danish cases of Shewanella alga bacteremia in two patients with chronic lower leg ulcers are reported. Both patients were admitted to the hospital during the same month of a very warm summer and had been exposed to the same marine environment, thereby suggesting the same source...

  6. Risk Factors of Endocarditis in Patients with Enterococcus faecalis Bacteremia

    DEFF Research Database (Denmark)

    Dahl, Anders; Lauridsen, Trine K; Arpi, Magnus

    2016-01-01

    BACKGROUND:  The NOVA score is a recently developed diagnostic tool to identify patients with increased risk of infective endocarditis (IE) among patients with Enterococcus faecalis (EF) bacteremia. We aim to validate an adapted version of the NOVA score and to identify risk factors for IE...... in a sensitivity of 97%, specificity of 23%, a negative predictive value of 95% and a positive predictive value of 38%. CONCLUSION:  Monomicrobial EF bacteremia, community acquisition, prosthetic heart valve and male sex are associated with increased risk of IE. In our retrospective cohort, the adapted NOVA score...

  7. Comparative Study of Plasma Endotoxin with Procalcitonin Levels in Diagnosis of Bacteremia in Intensive Care Unit Patients

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2016-01-01

    Conclusions: Plasma endotoxin was more related to GN than to Gram-positive bacteremia, and that endotoxin level was species dependent, but PCT level remained relatively more stable within the GN bacteria caused bacteremia. Both GN and positive bacteria caused bacteremia in the ICU patients in different regions of China. And PCT is a more valuable biomarker than endotoxin in the diagnosis of bacteremia.

  8. Incidence of bacteremia after chewing, tooth brushing and scaling in individuals with periodontal inflammation

    DEFF Research Database (Denmark)

    Larsen, F.L.; Kilian, Mogens; Holmstrup, P.

    2006-01-01

    Scientific rationale for study: Bacteremia occurs with various frequency after oral procedures. Periodontal disease may affect the incidence, magnitude, duration and bacterial spectrum of bacteremia. Principle findings: The incidence and magnitude of bacteremia after scaling was significantly......: The prevention and treatment of periodontal diseases appear to be crucial for the prevention of bacteremia associated with oral procedures....... higher in periodontitis than in gingivitis patients and healthy control individuals. In periodontitis patients, the magnitude of bacteremia was associated with gingival index, plaque index and number of sites with bleeding on probing, but not with probing pocket depth measurements. Practical implications...

  9. Carbapenem-resistant Pseudomonas aeruginosa: association with virulence genes and biofilm formation.

    Science.gov (United States)

    Rossi Gonçalves, Iara; Dantas, Raquel Cristina Cavalcanti; Ferreira, Melina Lorraine; Batistão, Deivid William da Fonseca; Gontijo-Filho, Paulo Pinto; Ribas, Rosineide Marques

    Pseudomonas aeruginosa is an opportunistic pathogen that causes frequently nosocomial infections, currently becoming more difficult to treat due to the various resistance mechanisms and different virulence factors. The purpose of this study was to determine the risk factors independently associated with the development of bacteremia by carbapenem-resistant P. aeruginosa, the frequency of virulence genes in metallo-β-lactamases producers and to evaluate their ability to produce biofilm. We conducted a case-control study in the Uberlândia Federal University - Hospital Clinic, Brazil. Polymerase Chain Reaction was performed for metallo-β-lactamases and virulence genes. Adhesion and biofilm assays were done by quantitative tests. Among the 157 strains analyzed, 73.9% were multidrug-resistant, 43.9% were resistant to carbapenems, 16.1% were phenotypically positive for metallo-β-lactamases, and of these, 10.7% were positive for blaSPM gene and 5.3% positive for blaVIM. The multivariable analysis showed that mechanical ventilation, enteral/nasogastric tubes, primary bacteremia with unknown focus, and inappropriate therapy were independent risk factors associated with bacteremia. All tested strains were characterized as strongly biofilm producers. A higher mortality was found among patients with bacteremia by carbapenem-resistant P. aeruginosa strains, associated independently with extrinsic risk factors, however it was not evident the association with the presence of virulence and metallo-β-lactamases genes. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  10. Carbapenem-resistant Pseudomonas aeruginosa: association with virulence genes and biofilm formation

    Directory of Open Access Journals (Sweden)

    Iara Rossi Gonçalves

    Full Text Available Abstract Pseudomonas aeruginosa is an opportunistic pathogen that causes frequently nosocomial infections, currently becoming more difficult to treat due to the various resistance mechanisms and different virulence factors. The purpose of this study was to determine the risk factors independently associated with the development of bacteremia by carbapenem-resistant P. aeruginosa, the frequency of virulence genes in metallo-β-lactamases producers and to evaluate their ability to produce biofilm. We conducted a case–control study in the Uberlândia Federal University – Hospital Clinic, Brazil. Polymerase Chain Reaction was performed for metallo-β-lactamases and virulence genes. Adhesion and biofilm assays were done by quantitative tests. Among the 157 strains analyzed, 73.9% were multidrug-resistant, 43.9% were resistant to carbapenems, 16.1% were phenotypically positive for metallo-β-lactamases, and of these, 10.7% were positive for blaSPM gene and 5.3% positive for blaVIM. The multivariable analysis showed that mechanical ventilation, enteral/nasogastric tubes, primary bacteremia with unknown focus, and inappropriate therapy were independent risk factors associated with bacteremia. All tested strains were characterized as strongly biofilm producers. A higher mortality was found among patients with bacteremia by carbapenem-resistant P. aeruginosa strains, associated independently with extrinsic risk factors, however it was not evident the association with the presence of virulence and metallo-β-lactamases genes.

  11. Neurocognitive Outcomes at 10 Years of Age in Extremely Preterm Newborns with Late-Onset Bacteremia.

    Science.gov (United States)

    Bright, H Reeve; Babata, Kikelomo; Allred, Elizabeth N; Erdei, Carmina; Kuban, Karl C K; Joseph, Robert M; O'Shea, T Michael; Leviton, Alan; Dammann, Olaf

    2017-08-01

    To evaluate the difference in 10-year neurocognitive outcomes between extremely low gestational age newborns without bacteremia and those with suspected or confirmed late-onset bacteremia. Neurocognitive function was evaluated at 10 years of age in 889 children born at <28 weeks of gestation and followed from birth. Definite (culture-positive) late-onset bacteremia during postnatal weeks 2-4 was identified in 223 children, and 129 children had suspected bacteremia. Infants with the lowest gestational age and birth weight z-score had the highest prevalence of definite and suspected late-onset bacteremia. Compared with peers with no or suspected bacteremia, infants with definite bacteremia performed worse on tests of general cognitive ability, language, academic achievement, and executive function, even after adjustment for potential confounders. Adjustment for low IQ attenuated the associations between bacteremia and all dysfunctions at age 10 years. Children with suspected bacteremia did not differ appreciably from those with no evidence of bacteremia. The motor domain was unaffected. Extremely low gestational age newborns who had definite late bacteremia during postnatal weeks 2-4 are at heightened risk of neurocognitive limitations at age 10 years. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Evaluation of the incidence of bacteremia following middle ear operations

    Directory of Open Access Journals (Sweden)

    Mohammad Naeimi

    2009-01-01

    Full Text Available Introduction: Bacteremia following middle ear surgeries occurs in a significant number of patients. The aim of this study is to investigate the incidence of bacteremia following middle ear surgeries. Materials and Methods: Sixty two patients who where candidates for middle ear operation were enrolled in this study. Blood samples were obtained from each patient immediately before and after operation for bacteriologic analysis. Demographic and middle ear disease characteristics were also recorded for each patient. Results: In 2 culture samples obtained before the operation and in 15 culture samples obtained after the operation, blood cultures were positive. One postoperative sample was excluded from the study due to probability of contamination. Of 14 postoperative cultures, staphylococcus epidermidis and streptococcus pyogenes were positive in 8 and 4 cases, respectively. There were no significant correlations between positive culture and age, otorrhea (duration and odor, surgical approach, type of surgery and pathological condition of patients. Conclusion: Risk of bacteremia following middle ear operations should be considered especially in patients who are high risk for postoperative endocarditis. Considering the serious complications of bacteremia, prophylactic measures are necessary in middle ear operations in this group of patients.    

  13. Agrobacterium radiobacter bacteremia in pediatric patients: case report and review.

    Science.gov (United States)

    Amaya, Rene A; Edwards, Morven S

    2003-02-01

    Agrobacterium radiobacter is an opportunistic pathogen often associated with indwelling catheters. We report five children with central venous catheter-associated A. radiobacter bacteremia and review the characteristics of pediatric Agrobacterium infections. Cure was achieved with appropriate antibiotics, often ticarcillin-clavulanate and gentamicin, and removal of the catheter.

  14. Heterogeneity of the humoral immune response following Staphylococcus aureus bacteremia

    NARCIS (Netherlands)

    N.J. Verkaik (Nelianne); H.A.M. Boelens (Hélène); C.P. de Vogel (Corné); M. Tavakol (Mehri); L.G.M. Bode (Lonneke); H.A. Verbrugh (Henri); A.F. van Belkum (Alex); W.J.B. van Wamel (Willem)

    2010-01-01

    textabstractExpanding knowledge on the humoral immune response in Staphylococcus aureus-infected patients is a mandatory step in the development of vaccines and immunotherapies. Here, we present novel insights into the antibody responses following S. aureus bacteremia. Fifteen bacteremic patients

  15. Increased risk of arterial thromboembolic events after Staphylococcus aureus bacteremia

    DEFF Research Database (Denmark)

    Mejer, N; Gotland, N; Uhre, M L

    2015-01-01

    OBJECTIVES: An association between infection and arterial thromboembolic events (ATE) has been suggested. Here we examined the risk of myocardial infarction (MI), stroke and other ATE after Staphylococcus aureus bacteremia (SAB). METHODS: Danish register-based nation-wide observational cohort study...

  16. A rabbit model of non-typhoidal Salmonella bacteremia.

    Science.gov (United States)

    Panda, Aruna; Tatarov, Ivan; Masek, Billie Jo; Hardick, Justin; Crusan, Annabelle; Wakefield, Teresa; Carroll, Karen; Yang, Samuel; Hsieh, Yu-Hsiang; Lipsky, Michael M; McLeod, Charles G; Levine, Myron M; Rothman, Richard E; Gaydos, Charlotte A; DeTolla, Louis J

    2014-09-01

    Bacteremia is an important cause of morbidity and mortality in humans. In this study, we focused on the development of an animal model of bacteremia induced by non-typhoidal Salmonella. New Zealand White rabbits were inoculated with a human isolate of non-typhoidal Salmonella strain CVD J73 via the intra-peritoneal route. Blood samples were collected at specific time points and at euthanasia from infected rabbits. Additionally, tissue samples from the heart, lungs, spleen, gastrointestinal tract, liver and kidneys were obtained at euthanasia. All experimentally infected rabbits displayed clinical signs of disease (fever, dehydration, weight loss and lethargy). Tissues collected at necropsy from the animals exhibited histopathological changes indicative of bacteremia. Non-typhoidal Salmonella bacteria were detected in the blood and tissue samples of infected rabbits by microbiological culture and real-time PCR assays. The development of this animal model of bacteremia could prove to be a useful tool for studying how non-typhoidal Salmonella infections disseminate and spread in humans. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Brucella bacteremia in patients with acute leukemia: a case series

    Directory of Open Access Journals (Sweden)

    Al-Anazi Khalid

    2007-11-01

    Full Text Available Abstract Background Brucellosis may cause serious infections in healthy individuals living in countries that are endemic for the infection. However, reports of brucella infections in immunocompromised hosts are relatively rare. Case Presentations Reported here are two patients with acute leukemia who developed Brucella melitensis bacteremia during their follow up at the Armed Forces Hospital in Riyadh. The first patient developed B. melitensis bacteremia during the transformation of his myelodysplasia into acute myeloid leukemia. The second patient developed B. melitensis bacteremia while his acute lymphoblastic leukemia was under control. Interestingly, he presented with acute cholecystitis during the brucella sepsis. Both brucella infections were associated with a marked reduction in the hematological parameters in addition to other complications. The bacteremic episodes were successfully treated with netilmicin, doxycycline and ciprofloxacin. Conclusion Brucellosis can cause systemic infections, complicated bacteremia and serious morbidity in patients with acute leukemia living in endemic areas. These infections may occur at the presentation of the leukemia or even when the leukemia is in remission. Nevertheless, the early diagnosis of brucellosis and the administration of appropriate antimicrobial therapy for sufficient duration usually improves the outcome in these immunocompromised patients.

  18. Predictors of bacteremia in emergency department patients with suspected infection.

    Science.gov (United States)

    Chase, Maureen; Klasco, Richard S; Joyce, Nina R; Donnino, Michael W; Wolfe, Richard E; Shapiro, Nathan I

    2012-11-01

    The goal of this study is to identify clinical variables associated with bacteremia. Such data could provide a rational basis for blood culture testing in emergency department (ED) patients with suspected infection. This is a secondary analysis of a prospective cohort of ED patients with suspected infection. Data collected included demographics, vital signs, medical history, suspected source of infection, laboratory and blood culture results and outcomes. Bacteremia was defined as a positive blood culture by Centers for Disease Control criteria. Clinical variables associated with bacteremia on univariate logistic regression were entered into a multivariable model. There were 5630 patients enrolled with an average age of 59.9 ± 19.9 years, and 54% were female. Blood cultures were obtained on 3310 (58.8%). There were 409 (12.4%) positive blood cultures, of which 68 (16.6%) were methicillin-resistant Staphylococcus aureus (MRSA) and 161 (39.4%) were Gram negatives. Ten covariates (respiratory failure, vasopressor use, neutrophilia, bandemia, thrombocytopenia, indwelling venous catheter, abnormal temperature, suspected line or urinary infection, or endocarditis) were associated with all-cause bacteremia in the final model (c-statistic area under the curve [AUC], 0.71). Additional factors associated with MRSA bacteremia included end-stage renal disease (odds ratio [OR], 3.9; 95% confidence interval [CI], 1.9-7.8) and diabetes (OR, 2.0; 95% CI, 1.1-3.6) (AUC, 0.73). Factors strongly associated with Gram-negative bacteremia included vasopressor use in the ED (OR, 2.8; 95% CI, 1.7-4.6), bandemia (OR, 3.5; 95% CI, 2.3-5.3), and suspected urinary infection (OR, 4.0; 95% CI, 2.8-5.8) (AUC, 0.75). This study identified several clinical factors associated with bacteremia as well as MRSA and Gram-negative subtypes, but the magnitude of their associations is limited. Combining these covariates into a multivariable model moderately increases their predictive value. Copyright

  19. Survey of Enteric Pathogens Causing Bacteremia in Cancer Patients

    Directory of Open Access Journals (Sweden)

    Enayatollah Kalantar

    2014-05-01

    Full Text Available Background: Symptomatic bacteraemia, is a frequent condition among cancer patients with a significant morbidity and mortality all over the world. Objectives: The aim of this study was to determine the burden of enteric pathogens causing bacteremia among cancer patients. Patients and Methods: Ten ml blood samples were withdrawn from the cancer patients under aseptic conditions. The blood specimens were added to the blood culture bottles and incubated at 37°C. The bacterial isolates from these samples were identified by routine biochemical reactions. Results: During the study period, 68 blood samples from cancer patients were analyzed for bacteremia. Of these patients, six were female (08/82% and 62 were male (91.18%; with age ranging from under 40 years to 85 years old (mean, 63 years. Gastro-intestinal cancer and cancers of head and neck were the most frequent cancer types in the studied group, accounting for 51 (75% and 15 (22.1% cases, respectively. The mean weight of patients was 69.18 Kg (range: 49-100 Kg. Similarly, the mean length of hospital stay was 8 days (range: 4-12 days. Positive blood cultures were detected in only 12 (17.65% and 11 (91.7% blood specimens from the Cancer Institute, Tehran, compared with one (08.33% from Shahid Kamali hospital, Karaj. From these patients, 15 bacteria were isolated; E. coli alone outnumbered other species and accounted for 33.33% of the episodes of bacteremia. Conclusions: In conclusion, our investigation revealed that cancers of GI tract are the most common cancer types causing bacteremia and also we identified that most common bacteria causing bacteremia in Cancer Institute, Tehran and Shahid Kamali Hospital, Karaj, are E. coli and S. aureus

  20. Experimental gingivitis, bacteremia and systemic biomarkers: a randomized clinical trial.

    Science.gov (United States)

    Kinane, D F; Zhang, P; Benakanakere, M; Singleton, J; Biesbrock, A; Nonnenmacher, C; He, T

    2015-12-01

    Bacteremia and systemic inflammatory markers are associated with periodontal and systemic diseases and may be linking mechanisms between these conditions. We hypothesized that in the development of gingival inflammation, systemic markers of inflammation and bacteremia would increase. To study the effect of bacteremia on systemic inflammatory markers, we recruited 80 subjects to participate in an experimental gingivitis study. Subjects were stratified based on gender, smoking and the number of bleeding sites and then randomized to one of two groups: control group (n = 40) or experimental gingivitis group (n = 40). Subjects in the control group conducted an oral hygiene regimen: brushing twice daily with a regular sodium fluoride cavity protection dentifrice and a standard manual toothbrush, flossing twice daily, and mouth rinsing with an anti-cavity fluoride rinse once daily. The experimental group stopped brushing and flossing, and used only the fluoride anti-cavity mouth rinse for 21 d. Seventy-nine of 80 subjects were evaluable. One subject in the control group was excluded from the results due to antibiotic use during the study. Our data showed the experimental gingivitis group exhibited a significant (p gingival inflammatory indices relative to baseline and the control group but a decrease in bacteremia and soluble intercellular adhesion molecule-1 levels vs. baseline. Bacteremia was negatively correlated with gingival inflammatory indices and soluble intercellular adhesion molecule-1 levels in the experimental gingivitis group, thus negating our hypothesis. We conclude that there are marked differences in systemic cytokine levels over the course of short-term experimentally induced gingivitis and further conclude that a long-term periodontitis study must be considered to address mechanisms whereby oral diseases may affect systemic diseases. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Bacteremia and "Endotipsitis" following transjugular intrahepatic portosystemic shunting

    Science.gov (United States)

    Mizrahi, Meir; Roemi, Lilach; Shouval, Daniel; Adar, Tomer; Korem, Maya; Moses, Alon; Bloom, Alan; Shibolet, Oren

    2011-01-01

    AIM: To identify all cases of bacteremia and suspected endotipsitis after Transjugular intrahepatic portosystemic shunting (TIPS) at our institution and to determine risk factors for their occurrence. METHODS: We retrospectively reviewed records of all patients who underwent TIPS in our institution between 1996 and 2009. Data included: indications for TIPS, underlying liver disease, demographics, positive blood cultures after TIPS, microbiological characteristics, treatment and outcome. RESULTS: 49 men and 47 women were included with a mean age of 55.8 years (range 15-84). Indications for TIPS included variceal bleeding, refractory ascites, hydrothorax and hepatorenal syndrome. Positive blood cultures after TIPS were found in 39/96 (40%) patients at various time intervals following the procedure. Seven patients had persistent bacteremia fitting the definition of endotipsitis. Staphylococcus species grew in 66% of the positive cultures, Candida and enterococci species in 15% each of the isolates, and 3% cultures grew other species. Multi-variate regression analysis identified 4 variables: hypothyroidism, HCV, prophylactic use of antibiotics and the procedure duration as independent risk factors for positive blood cultures following TIPS (P < 0.0006, 0.005, 0.001, 0.0003, respectively). Prophylactic use of antibiotics before the procedure was associated with a decreased risk for bacteremia, preventing mainly early infections, occurring within 120 d of the procedure. CONCLUSION: Bacteremia is common following TIPS. Risk factors associated with bacteremia include failure to use prophylactic antibiotics, hypothyroidism, HCV and a long procedure. Our results strongly support the use of prophylaxis as a means to decrease early post TIPS infections. PMID:21731907

  2. The daily risk of bacteremia during hospitalization and associated 30-day mortality evaluated in relation to the traditional classification of bacteremia

    DEFF Research Database (Denmark)

    Nielsen, Stig Lønberg; Lassen, Annmarie Touborg; Kolmos, Hans Jørn

    2016-01-01

    BACKGROUND: We investigated the overall and daily incidence of bacteremia among hospitalized patients and evaluated the traditional classification of bacteremia (community-onset vs nosocomial based on a 48-hour time window) by means of the daily incidence and associated 30-day mortality. METHODS...

  3. Antibiotic resistance patterns of Pseudomonas spp. isolated from the River Danube

    Directory of Open Access Journals (Sweden)

    Clemens eKittinger

    2016-05-01

    Full Text Available Spread and persistence of antibiotic resistance pose a severe threat to human health, yet there is still lack of knowledge about reservoirs of antibiotic resistant bacteria in the environment. We took the opportunity of the Joint Danube Survey 3 (JDS3, the world's biggest river research expedition of its kind in 2013, to analyse samples originating from different sampling points along the whole length of the river. Due to its high clinical relevance, we concentrated on the characterization of Pseudomonas spp. and evaluated the resistance profiles of Pseudomonas spp. which were isolated from eight sampling points. In total, 520 Pseudomonas isolates were found, 344 (66.0% isolates were identified as Pseudomonas putida, and 141 (27.1% as Pseudomonas fluorescens, all other Pseudomonas species were represented by less than five isolates, among those two P. aeruginosa isolates. Thirty seven percent (37% of all isolated Pseudomonas species showed resistance to at least one out of eleven tested antibiotics. The most common resistance was against meropenem (30.4% / 158 isolates piperacillin/tazobactam (10.6% / 55 isolates and ceftazidime (4.2% / 22 isolates. 16 isolates (3.1% / 16 isolates were multi-resistant. For each tested antibiotic at least one resistant isolate could be detected. Sampling points from the upper stretch of the River Danube showed more resistant isolates than downriver. Our results suggest that antibiotic resistance can be acquired by and persists even in Pseudomonas species that are normally not in direct contact with humans. A possible scenario is that these bacteria provide a reservoir of antibiotic resistance genes that can spread to related human pathogens by horizontal gene transfer.

  4. Antifungal Activity of Selected Indigenous Pseudomonas and Bacillus from the Soybean Rhizosphere

    Science.gov (United States)

    León, M.; Yaryura, P. M.; Montecchia, M. S.; Hernández, A. I.; Correa, O. S.; Pucheu, N. L.; Kerber, N. L.; García, A. F.

    2009-01-01

    The purpose of this study was to isolate and select indigenous soil Pseudomonas and Bacillus bacteria capable of developing multiple mechanisms of action related to the biocontrol of phytopathogenic fungi affecting soybean crops. The screening procedure consisted of antagonism tests against a panel of phytopathogenic fungi, taxonomic identification, detection by PCR of several genes related to antifungal activity, in vitro detection of the antifungal products, and root colonization assays. Two isolates, identified and designated as Pseudomonas fluorescens BNM296 and Bacillus amyloliquefaciens BNM340, were selected for further studies. These isolates protected plants against the damping-off caused by Pythium ultimum and were able to increase the seedling emergence rate after inoculation of soybean seeds with each bacterium. Also, the shoot nitrogen content was higher in plants when seeds were inoculated with BNM296. The polyphasic approach of this work allowed us to select two indigenous bacterial strains that promoted the early development of soybean plants. PMID:20016811

  5. Rhodococcus bacteremia in cancer patients is mostly catheter related and associated with biofilm formation.

    Directory of Open Access Journals (Sweden)

    Fadi Al Akhrass

    Full Text Available Rhodococcus is an emerging cause of opportunistic infection in immunocompromised patients, most commonly causing cavitary pneumonia. It has rarely been reported as a cause of isolated bacteremia. However, the relationship between bacteremia and central venous catheter is unknown. Between 2002 and 2010, the characteristics and outcomes of seventeen cancer patients with Rhodococcus bacteremia and indwelling central venous catheters were evaluated. Rhodococcus bacteremias were for the most part (94% central line-associated bloodstream infection (CLABSI. Most of the bacteremia isolates were Rhodococcus equi (82%. Rhodococcus isolates formed heavy microbial biofilm on the surface of polyurethane catheters, which was reduced completely or partially by antimicrobial lock solution. All CLABSI patients had successful response to catheter removal and antimicrobial therapy. Rhodococcus species should be added to the list of biofilm forming organisms in immunocompromised hosts and most of the Rhodococcus bacteremias in cancer patients are central line associated.

  6. Fatal bacteremia due to Anaerobiospirillum succiniciproducens: first description in Brazil

    Directory of Open Access Journals (Sweden)

    Carina Secchi

    Full Text Available Anaerobiospirillum succiniciproducens is an anaerobic, Gram-negative, spiral shaped bacteria, which is motile by means of bipolar tuffs of flagella. This organism appears to be a rare cause of bacteremia in humans, and it usually affects patients submitted to immunosuppressive therapy. Anaerobiospirillum succiniciproducens resembles Campylobacter spp. in Gram-stained preparations, however, it is considered resistant to most antimicrobial drugs that are used to treat Campylobacter infections. We observed Gram-negative, spiral shaped bacteria in Gram-stained preparations from blood culture flasks. Growth occurred only under anaerobic incubation, and identification to the species level was achieved by PCR amplification of the 16S rRNA gene, followed by direct sequencing and a GenBank homology search. To the best of our knowledge, this is the first reported Brazilian case of Anaerobiospirillum succiniciproducens bacteremia.

  7. Streptococcus bovis Bacteremia in Neonates in a Predominantly Hispanic Population

    Directory of Open Access Journals (Sweden)

    YI eJIA

    2015-10-01

    Full Text Available Background: Streptococcus bovis bacteremia has been associated with gastrointestinal diseases, especially colon cancer, neoplastic colon polyps and other malignancies of the GI tract in adults. Sporadic cases of S. bovis disease have also been reported in neonates and young infants. Although uncommon, S. bovis infection can cause fulminant neonatal sepsis and meningitis. Objectives: We report a series of pediatric patients with S. bovis bacteremia in a county hospital in a United States - Mexico border city in order to examine the demographic and clinical associations. Methods: We characterized the demographic and clinical features in all pediatric patients with blood cultures positive for S. bovis at University Medical Center in El Paso, Texas between January 2000 and December 2010. Hospital records were systematically reviewed by using a standardized protocol.Results: A total of 7 episodes of S. bovis bacteremia were documented in 7 pediatric patients (4 female and 3 male. Mean age was 1.2 days (range 1-3 days, all were Hispanic, average birth weight (3.25 kg. Mode of delivery was spontaneous vaginal delivery (5 and Caesarian section (2. All of our patients developed early (< 1 week onset disease and presented with signs of respiratory distress. Five out of 7 babies presented with abdominal distention and diarrhea. Six had clinical evidence of sepsis at presentation. Respiratory distress was the most common manifestation of sepsis (7. Aspiration pneumonia was diagnosed in 2 of them. Most patients were treated with a combination of antibiotics (6, either ampicillin and gentamicin or ampicillin and cefotaxime, and one with ampicillin alone. None of the pediatric patients had endoscopy and none of them died.Conclusions: S. bovis is considered an uncommon pathogen in the newborn, but can be associated with substantial morbidity and mortality if not identified and treated early. Physicians should be alert to the less common presentation of neonatal

  8. Nosocomial bacteremia due to Kluyvera cryocrescens: Case report and literature review

    OpenAIRE

    Yoshino, Yusuke; Nakazawa, Susumu; Otani, Sumire; Sekizuka, Eiichi; Ota, Yasuo

    2016-01-01

    Kluyvera cryocrescens infection has been considered rare; clinical features of K. cryocrescens bacteremia remain unclear because few reports have been published. We report a case of K. cryocrescens bacteremia in an adult male patient and review the literature. Our case was one with nosocomial bacteremia in a patient with interstitial lung disease. The primary infection site was undetermined, although he had an indwelling peripheral intravenous catheter and a urinary catheter. Piperacilin/tazo...

  9. [Predictive ability of clinical parameters of bacteremia in hemodialysed patients].

    Science.gov (United States)

    Egea, Ana L; Vilaró, Mario; De la Fuente, Jorge; Cuestas, Eduardo; Bongiovanni, María E

    2012-01-01

    No clinical events to differentiate bacteteremia from other pathologies in hemodialysis patients therefore the physicians makes diagnosis and treatment decisions based on clinical evidence an local epidemiology. the aim of this work was to study the frequency of microorganism isolated from blood culture of hemodialysis patients with suspected bacteraemia and evaluate Sensitivity (S) and Specificity (E) of medical diagnostic orientation in this cases of suspected Materials and methods: we performed an observational and prospective study for one year in hemodialysis patient with suspected bacteremia. We evaluated blood pressure, temperature (Tº), altered conscious state (AEC), respiratory frequency (FR), chills (ESC),diarrhea (DIARR), blood culture results and microbiological identification. We work with the mean ± standar desviation for continuous variables and frequencies for categorical variables We analyzed S, E, negative predictive value (VPN), positive predictive value (VPP) RESULTADOS: a total of 87 events with suspected bacteremia 34 (39%) were confirmed with positive blood culture the most common microorganisms were cocci Gram positive (CGP) 65%, Most relevant clinical variables were PCP ≥ 2 (VPN 81%), Tº ≥ 38 (VPN 76%) and AEC (E 98% y VPP 80%). CGP were the most prevalent microorganisms None of the clinical variables shows high S and E indicating low usefulness as a predictive tool of bacteremia Excepting AEC with E98% and VPP 80% but it would be necessary to evaluate this variable with a more number patient. Results justify to routine HC use like diagnostic tool.

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

    Science.gov (United States)

    2017-02-02

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

  11. Invasive behaviour and depolarization effect of Pseudomonas ...

    African Journals Online (AJOL)

    ... reveals that P. fluorescens induces the sequential activation of a constitutive calcium dependent NOS and that of an inducible NOS activated by LPS. Ours results also suggest that P. fluorescens cytotoxicity and invasion are not mutually exclusive events. Key Words: Cytotoxicity, Lipopolysaccharide, Patch-clamp, Invasion ...

  12. Comparative evaluation of organic formulations of Pseudomonas ...

    African Journals Online (AJOL)

    Jane

    2011-07-20

    Jul 20, 2011 ... ment of the potential biocontrol agent P. fluorescens and explore the efficacy of P. fluorescens based bioformu- lations in suppressing bacterial wilt of brinjal in pot experiment and field conditions. MATERIALS AND METHODS. Source of the pathogen. Brinjal plants showing typical symptoms of bacterial wilt ...

  13. Pseudomonas granadensis sp. nov., a new bacterial species isolated from the Tejeda, Almijara and Alhama Natural Park, Granada, Spain.

    Science.gov (United States)

    Pascual, Javier; García-López, Marina; Bills, Gerald F; Genilloud, Olga

    2015-02-01

    During the course of screening bacterial isolates as sources of as-yet unknown bioactive compounds with pharmaceutical applications, a chemo-organotrophic, Gram-negative bacterium was isolated from a soil sample taken from the Tejeda, Almijara and Alhama Natural Park, Granada, Spain. Strain F-278,770(T) was oxidase- and catalase-positive, aerobic, with a respiratory type of metabolism with oxygen as the terminal electron acceptor, non-spore-forming and motile by one polar flagellum, although some cells had two polar flagella. Phylogenetic analysis of the 16S rRNA, gyrB, rpoB and rpoD genes revealed that strain F-278,770(T) belongs to the Pseudomonas koreensis subgroup (Pseudomonas fluorescens lineage), with Pseudomonas moraviensis, P. koreensis, P. baetica and P. helmanticensis as its closest relatives. Chemotaxonomic traits such as polar lipid and fatty acid compositions and G+C content of genomic DNA corroborated the placement of strain F-278,770(T) in the genus Pseudomonas. DNA-DNA hybridization assays and phenotypic traits confirmed that this strain represents a novel species of the genus Pseudomonas, for which the name Pseudomonas granadensis sp. nov. is proposed. The type strain is F-278,770(T) ( = DSM 28040(T) = LMG 27940(T)). © 2015 Fundacion MEDINA, Centro de Excelencia en Investigacion de Medicamentos Innovadores en Andalucia.

  14. Bacteremia and resistant gram-negative pathogens among under-fives in Tanzania.

    Science.gov (United States)

    Christopher, Alexandra; Mshana, Stephen E; Kidenya, Benson R; Hokororo, Aldofineh; Morona, Domenica

    2013-05-08

    Antibiotic resistance is one of the most serious public health concerns worldwide and is increasing at an alarming rate, making daily treatment decisions more challenging. This study is aimed at identifying local bacterial isolates and their antimicrobial susceptibility patterns to avoid irrational antibiotic use, especially in settings where unguided management occurs and febrile illnesses are predominant. A hospital-based prospective cross-sectional study was conducted from September 2011 to February 2012. Febrile children were serially recruited and demographic and clinical data were collected using a standardized data collection tool. A blood culture was performed and identification of the isolates was undertaken using in-house biochemical tests. Susceptibility to common antibiotics was investigated using the disc diffusion methods. Of the 1081 children admitted during the study period, 317 (29.3%) met the inclusion criteria and were recruited, of whom 195 (61.5%) and 122 (38.5%) were male and female respectively. The median age was 18 months with an interquartile range of 9 to 36 months. Of the 317 children, 251 (79.2%) were below or equal to 36 months of age. The prevalence of bacteremia was 6.6%. A higher prevalence of bacteraemia was observed in children below 36 months than in those ≥ 36 months (7.5% vs. 3.0%, p = 0.001). Predictors of bacteraemia were an axillary temperature of >38.5 °C (OR =7, 95% CI = 2.2 - 14.8, p-value = 0.0001), a positive malaria slide (OR =5, 95% CI = 3.0 - 21.2, p-value = 0.0001) and a high neutrophils' count (OR =21 95% CI = 5.6 - 84, p-value = 0.0001). Escherichia coli and Klebsiella pneumoniae accounted for 7 (33.3%) and 6 (28.6%) of all the isolates respectively. Others gram-negatives bacteria were Citrobacter spp 2 (9.5%), Enterobacter spp 1 (4.25%), Pseudomonas spp 2 (9.5%), Proteus spp 1 (4.25%) and Salmonella spp 1 (4.25%). These isolates were highly resistant to ampicillin (95%), co

  15. Pseudomonas Lipopeptide Biosurfactants

    DEFF Research Database (Denmark)

    Bonnichsen, Lise

    Pseudomonas lipopetide biosurfactants are amphiphilic molecules with a broad range of natural functions. Due to their surface active properties, it has been suggested that Pseudomonas lipopetides potentially play a role in biodegradation of hydrophobic compounds and have essential functions...... in biofilm formation, however, detailed studies of these roles have not yet been carried out. The overall aim of this PhD project was therefore to elucidate in more depth the roles played by Pseudomonas lipopetides in pollutant biodegradation and biofilm formation. This study investigated the effect...... of the Pseudomonas lipopeptides belonging to different structural groups on important biodegradation parameters, mainly; solubilization and emulsification of hydrophobic pollutants (alkanes and PAHs) and increase of cell surface hydrophobicity of bacterial degraders. Ultimately, it was tested if these parameters led...

  16. Chronic Liver Disease Impairs Bacterial Clearance in a Human Model of Induced Bacteremia

    OpenAIRE

    Ashare, Alix; Stanford, Clark; Hancock, Patricia; Stark, Donna; Lilli, Kathleen; Birrer, Emily; Nymon, Amanda; Doerschug, Kevin C.; Hunninghake, Gary W

    2009-01-01

    Sepsis often causes impaired hepatic function. Patients with liver disease have an increased risk of bacteremia. This is thought to be secondary to impaired reticuloendothelial system function. However, this has not been demonstrated clinically. Since transient bacteremia occurs following toothbrushing, we hypothesized that subjects with cirrhosis would have impaired bacterial clearance following toothbrushing compared with subjects with pulmonary disease and healthy controls. After baseline ...

  17. Antimicrobial Activity of Various Plant Extracts on Pseudomonas Species Associated with Spoilage of Chilled Fish

    Directory of Open Access Journals (Sweden)

    Osan Bahurmiz

    2016-11-01

    Full Text Available The antimicrobial activity of various plant extracts on Pseudomonas bacteria isolated from spoiled chilled tilapia (Oreochromis sp. was evaluated in this study. In the first stage of this study, red tilapia was subjected to chilled storage (4°C for 3 weeks, and spoilage bacteria were isolated and identified from the spoiled fish. Pseudomonas was the dominant bacteria isolated from the spoiled fish and further identification revealed that P. putida, P. fluorescens and Pseudomonas spp. were the main species of this group. In the second stage, methanolic extracts of 15 selected plant species were screened for their antimicrobial activity, by agar disc diffusion method, against the Pseudomonas isolates. Results indicated that most of the extracts had different degrees of activity against the bacterial isolates. The strongest activity was exhibited by bottlebrush flower (Callistemon viminalis extract. This was followed by extracts from guava bark (Psidium guajava and henna leaf (Lawsonia inermis. Moderate antimicrobial activities were observed in extracts of clove (Syzygium aromaticum, leaf and peel of tamarind (Tamarindus indica, cinnamon bark (Cinnamomum zeylanicum, wild betel leaf (Piper sarmentosum and fresh thyme (Thymus spp.. Weak or no antimicrobial activity was observed from the remaining extracts. The potential antimicrobial activity shown by some plant extracts in this study could significantly contribute to the fish preservation.

  18. Influence of volatile organic compounds emitted by Pseudomonas and Serratia strains on Agrobacterium tumefaciens biofilms.

    Science.gov (United States)

    Plyuta, Vladimir; Lipasova, Valentina; Popova, Alexandra; Koksharova, Olga; Kuznetsov, Alexander; Szegedi, Erno; Chernin, Leonid; Khmel, Inessa

    2016-07-01

    The ability to form biofilms plays an important role in bacteria-host interactions, including plant pathogenicity. In this work, we investigated the action of volatile organic compounds (VOCs) produced by rhizospheric strains of Pseudomonas chlororaphis 449, Pseudomonas fluorescens B-4117, Serratia plymuthica IC1270, as well as Serratia proteamaculans strain 94, isolated from spoiled meat, on biofilms formation by three strains of Agrobacterium tumefaciens which are causative agents of crown-gall disease in a wide range of plants. In dual culture assays, the pool of volatiles emitted by the tested Pseudomonas and Serratia strains suppressed the formation of biofilms of A. tumefaciens strains grown on polycarbonate membrane filters and killed Agrobacterium cells in mature biofilms. The individual VOCs produced by the tested Pseudomonas strains, that is, ketones (2-nonanone, 2-heptanone, 2-undecanone), and dimethyl disulfide (DMDS) produced by Serratia strains, were shown to kill A. tumefaciens cells in mature biofilms and suppress their formation. The data obtained in this study suggest an additional potential of some ketones and DMDS as protectors of plants against A. tumefaciens strains, whose virulence is associated with the formation of biofilms on the infected plants. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  19. Dissemination and persistence of Pseudomonas spp. in small-scale dairy farms

    Directory of Open Access Journals (Sweden)

    Daniele Michele Nucera

    2016-05-01

    Full Text Available This study was aimed at collecting data on presence, dissemination and persistence of Pseudomonas in small-scale dairy farms. Six farms (located in Piedmont were visited three times over 2014: 116 waters (wells and different faucets/pipes and 117 environmental samples (milking equipments and drains were collected. Enumeration of Pseudomonadaceae was performed, 3-5 colonies/samples were selected for identification via 16SrDNA/oprI polymerase chain reaction (PCR, and typed by enterobacterial-repetitive- intergenic-consensus (ERIC-PCR. Pseudomonadaceae were detected in 77% of samples. No statistical differences were found among proportions of positives across farms, sample typologies and seasons. Most isolates were Pseudomonas fluorescens (45%, and ERIC-PCR showed 32 persistent types diffused across farms. All in all, Pseudomonas spp. represents a challenge, considering its presence over time in water as well as in teat cups, indicating a continuous source of contamination. Moreover, persistency of strains may indicate biofilm-formation and/or sanitisers resistance, therefore emphasising the role of primary production for preventing milk contamination by Pseudomonas spp.

  20. Nosocomial bacteremia due to Kluyvera cryocrescens: Case report and literature review.

    Science.gov (United States)

    Yoshino, Yusuke; Nakazawa, Susumu; Otani, Sumire; Sekizuka, Eiichi; Ota, Yasuo

    2016-01-01

    Kluyvera cryocrescens infection has been considered rare; clinical features of K. cryocrescens bacteremia remain unclear because few reports have been published. We report a case of K. cryocrescens bacteremia in an adult male patient and review the literature. Our case was one with nosocomial bacteremia in a patient with interstitial lung disease. The primary infection site was undetermined, although he had an indwelling peripheral intravenous catheter and a urinary catheter. Piperacilin/tazobactam was administered for 2 weeks and the bacteremia resolved. Unfortunately, there was acute exacerbation of the interstitial lung disease, which was fatal. According to our review, including our case, K. cryocrescens bacteremia tends to occur in immunocompromised hosts, and indwelling catheters might be risk factors. Extended spectrum cephalosporins, carbapenems, fluoroquinolones and tetracyclines are generally adequate agents for empiric therapy based on susceptibilities of K. cryocrescens clinical isolates.

  1. Clostridium difficile bacteremia: Report of two cases in French hospitals and comprehensive review of the literature

    Directory of Open Access Journals (Sweden)

    Mouna Doufair

    2017-01-01

    Full Text Available We report two cases of bacteremia due to Clostridium difficile from two French hospitals. The first patient with previously diagnosed rectal carcinoma underwent courses of chemotherapy, and antimicrobial treatment, and survived the C. difficile bacteremia. The second patient with colon perforation and newly diagnosed lung cancer underwent antimicrobial treatment in an ICU but died shortly after the episode of C. difficile bacteremia. A review of the literature allowed the identification of 137 cases of bacteremia between July 1962 and November 2016. Advanced age, gastro-intestinal disruption, severe underlying diseases and antimicrobial exposure were the major risk factors for C. difficile bacteremia. Antimicrobial therapy was primarily based on metronidazole and/or vancomycin. The crude mortality rate was 35% (21/60.

  2. Streptomyces bacteremia in a patient with actinomycotic mycetoma.

    Science.gov (United States)

    Joseph, Noyal Mariya; Harish, Belgode Narasimha; Sistla, Sujatha; Thappa, Devinder Mohan; Parija, Subhash Chandra

    2010-05-01

    A 29-year-old woman presented with multiple painful swelling with discharging sinuses over the scalp. Histopathological examination of the biopsy tissue was suggestive of actinomycotic mycetoma. Streptomyces spp. was isolated from blood culture. The patient was successfully treated with trimethoprim-sulfamethoxazole and crystalline penicillin. This case is reported because of the rare occurrence of bacteremia by Streptomyces spp. secondary to subcutaneous actinomycotic mycetoma. Moreover, an interesting association between successive two pregnancies and occurrence of mycetoma of the scalp was observed in this case.

  3. Both host and pathogen factors predispose to Escherichia coli urinary-source bacteremia in hospitalized patients.

    Science.gov (United States)

    Marschall, Jonas; Zhang, Lixin; Foxman, Betsy; Warren, David K; Henderson, Jeffrey P

    2012-06-01

    The urinary tract is the most common source for Escherichia coli bacteremia. Mortality from E. coli urinary-source bacteremia is higher than that from urinary tract infection. Predisposing factors for urinary-source E. coli bacteremia are poorly characterized. In order to identify urinary-source bacteremia risk factors, we conducted a 12-month prospective cohort study of adult inpatients with E. coli bacteriuria that were tested for bacteremia within ±1 day of the bacteriuria. Patients with bacteremia were compared with those without bacteremia. Bacterial isolates from urine were screened for 16 putative virulence genes using high-throughput dot-blot hybridization. Twenty-four of 156 subjects (15%) had E. coli bacteremia. Bacteremic patients were more likely to have benign prostatic hyperplasia (56% vs 19%; P = .04), a history of urogenital surgery (63% vs 28%; P = .001), and presentation with hesitancy/retention (21% vs 4%; P = .002), fever (63% vs 38%; P = .02), and pyelonephritis (67% vs 41%; P = .02). The genes kpsMT (group II capsule) (17 [71%] vs 62 [47%]; P = .03) and prf (P-fimbriae family) (13 [54%] vs 40 [30%]; P = .02) were more frequent in the urinary strains from bacteremic patients. Symptoms of hesitancy/retention (odds ratio [OR], 7.8; 95% confidence interval [CI], 1.6-37), history of a urogenital procedure (OR, 5.4; 95% CI, 2-14.7), and presence of kpsMT (OR, 2.9; 95% CI, 1-8.2) independently predicted bacteremia. Bacteremia secondary to E. coli bacteriuria was frequent (15%) in those tested for it. Urinary stasis, surgical disruption of urogenital tissues, and a bacterial capsule characteristic contribute to systemic invasion by uropathogenic E. coli.

  4. Spa type distribution in MRSA and MSSA bacteremias and association of spa clonal complexes with the clinical characteristics of bacteremia.

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    Jokinen, Elina; Lindholm, Laura; Huttunen, Reetta; Huhtala, Heini; Vuento, Risto; Vuopio, Jaana; Syrjänen, Jaana

    2018-02-10

    The genetic distribution of invasive methicillin-susceptible (MSSA) and resistant S. aureus (MRSA) strains has to be addressed in order to target infection control strategies. A large MRSA epidemic caused by a certain MRSA strain (spa type 067) broke out in 2001 in our health district. We wanted to investigate the current spa type distribution in MRSA and MSSA bacteremias and assess the potential association of spa clonal complexes (spaCC) with the clinical characteristics of S. aureus bacteremia. One hundred nine invasive MRSA isolates and 353 invasive MSSA isolates were spa typed and grouped into clonal complexes (spaCC). Spa type distribution was compared to that of colonizing MRSA strains. Spa type and spaCC data linked to clinical information on the course of bacteremic cases was used to search for differences in virulence between strains. Spa type distribution in MRSA is less heterogenic than in MSSA. t067 dominates both in MRSA colonisations and in invasive findings. Among MSSA, no such dominating strains were found. Of spaCCs, mortality was the highest in spaCC 067 (25.6%). SpaCC 008 was more often associated with endocarditis than other CCs (22.7 vs 5.8%, p = 0.013), spaCC 2133 with skin infections (68.4 vs 36.4%, p = 0.007), and spaCC 012 with foreign body infections (25.0 vs 9.3%, p = 0.029) than other clonal complexes. A single successful strain can explain the major proportion of MRSA among S. aureus bacteremias. Certain spaCCs showed association with certain clinical characteristics. These findings suggest that S. aureus strains differ in their virulence and invasiveness.

  5. Prevalência e fatores associados à bacteremia nos portadores de colecistite aguda litiásica Bacteremia - prevalence and associated factors in patients with acute calculous cholecystitis

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    André Luciano Baitello

    2004-12-01

    Full Text Available OBJETIVO: Determinar a prevalência de bacteremia e os fatores associados no período pré-operatório em portadores de colecistite aguda litiásica e analisar comparativamente as complicações e mortalidade nos pacientes com e sem bacteremia, que foram submetidos a colecistectomia de urgência. MÉTDODOS: Foram estudados, prospectivamente, 51 pacientes com diagnóstico histopatológico de colecistite aguda litiásica. O sistema Bactec foi o método utilizado para a detecção de bacteremia. As médias dos grupos foram analisadas quanto às variáveis clínicas e laboratoriais, relacionando-as com a bacteremia. RESULTADOS: A prevalência de bacteremia no pré-operatório foi de 15,68%, e a idade (p=0,024, a freqüência cardíaca (p=0,026, a freqüência respiratória (p=0,028, a creatinina (p=0,028 e a presença da SIRS (Síndrome da Resposta Inflamatória Sistêmica, p=0,016 associaram-se positivamente com a bacteremia. Nos portadores de bacteremia verificou-se um óbito, maior número de complicações gerais (p=0,045 e infecciosas (p=0,039 e maior tempo de internação (pBACKGROUND: Bacteremia seems to increase the morbidity and mortality in clinical and surgical conditions, however the importance and factors associated with it during acute calculous cholecystitis are not well established. The purpose of this study was to determine pre-operative prevalence, associated factors and prognosis of bacteremia in patients with acute calculous cholecystitis submitted to an emergency cholecystectomy. METHODS: A prospective study of 51 patients with histological diagnosis of acute calculous cholecystitis was designed. The Bactec System was used to detect bacteremia. Mean results of clinical and laboratory analyses were related to the presence of bacteremia. RESULTS: The pre-operative prevalence of bacteremia was of 15.68%. Age (P=0.024, heart rate (P=0.026, respiratory rate (P=0.028, serum creatinine (P=0.028 and presence of systemic inflammatory

  6. Bacteremia caused by Salmonella enterica serotype Choleraesuis in Taiwan.

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    Jean, Shio-Shin; Wang, Jen-Yu; Hsueh, Po-Ren

    2006-10-01

    Since 1995, there has been a steady increase in the number of reported cases of Salmonella enterica serotype Choleraesuis (S. Choleraesuis) sepsis in Taiwan. Representative Taiwanese survey data from 1996 to 2004 revealed that these adult patients with S. Choleraesuis bacteremia presented with primary bacteremia (57%, especially immunocompromised hosts), mycotic aneurysm (16%), and fever (86%) predominantly. S. Choleraesuis septicemia demonstrated a higher invasion index (with secondary involved sites) than other Salmonella spp. In swine experiments, the inoculation dose of 10(3) colony forming units S. Choleraesuis was cleared without apparent sequelae. Transmission of specific strains (with mutations of GyrA and parC, subsequently resistance to fluoroquinolones) from swine, and the acquisition of genes (CMY-2, AmpC complex) encoding beta-lactamases (with resistance to extended-spectrum cephalosporins) have been implicated in the evolution of multiresistant phenotypes of S. Choleraesuis. The virulence plasmid of S. Choleraesuis (pSCV), and other genes mediating adhesion to the epithelial cell membrane of the gastrointestinal tract, were considered important pathogenic factors for S. Choleraesuis. Vaccines for domestic animals combined with effective controls on antibiotic use offer the greatest potential to control the increasing impact of S. Choleraesuis on humans.

  7. Determination Pattern of Antimicrobial Resistance of Pseudomonas Isolated from Patients in a University Tertiary Hospital

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    Alka Hasani

    2017-07-01

    Full Text Available Introduction: Pseudomonas are ubiquitous bacteria widely present in nature. However, they have emerged as an opportunistic pathogen for humans. This bacterium is accountable for many localized and disseminated diseases, especially wounds in burn patients, respiratory infections, septicemia and bacteremia. Among all Pseudomonas species, P. aeruginosa is one of the important and most virulent species in hospital settings, while other pathogenic species include stutzeri, putida and fluorescence. The aim of this study was to assess pattern of antibiotic resistance in these bacteria isolated from a University teaching and treatment center. This cross-sectional study was conducted on 99 Pseudomonas strains (68 strains P. aeruginosa and 31 other Pseudomonas species isolated from various clinical specimens. Antimicrobial drug susceptibility test was performed using the disc agar diffusion method according to CLSI recommendations. In this study, among various clinical specimens sent to microbiology laboratory, wound (59.59% was found as a major source of Pseudomonas spp. Among various wards, Pseudomonas spp. was isolated more from patients admitted to burns ward (48.48%. Antibiotic susceptibility assay results revealed non susceptibility pattern towards most of the antibiotics; however, among all antibiotics tested, most common resistance was observed towards ceftazidime (76.76%. The results of this study shows the presence of Pseudomonas infection in the hospital setting and their developed resistance towards many conventional antibiotics, which is a concern at this treatment center. Thus, there exist a need for evaluation of careful and accurate measurement of resistance and assessment of exact drug administration policies. Therefore, to control the infection and prevent from increased prevalence of resistant strains appropriate resolution should be followed.

  8. Functional Analysis of Genes for Biosynthesis of Pyocyanin and Phenazine-1-Carboxamide from Pseudomonas aeruginosa PAO1

    Science.gov (United States)

    Mavrodi, Dmitri V.; Bonsall, Robert F.; Delaney, Shannon M.; Soule, Marilyn J.; Phillips, Greg; Thomashow, Linda S.

    2001-01-01

    Two seven-gene phenazine biosynthetic loci were cloned from Pseudomonas aeruginosa PAO1. The operons, designated phzA1B1C1D1E1F1G1 and phzA2B2C2D2E2F2G2, are homologous to previously studied phenazine biosynthetic operons from Pseudomonas fluorescens and Pseudomonas aureofaciens. Functional studies of phenazine-nonproducing strains of fluorescent pseudomonads indicated that each of the biosynthetic operons from P. aeruginosa is sufficient for production of a single compound, phenazine-1-carboxylic acid (PCA). Subsequent conversion of PCA to pyocyanin is mediated in P. aeruginosa by two novel phenazine-modifying genes, phzM and phzS, which encode putative phenazine-specific methyltransferase and flavin-containing monooxygenase, respectively. Expression of phzS alone in Escherichia coli or in enzymes, pyocyanin-nonproducing P. fluorescens resulted in conversion of PCA to 1-hydroxyphenazine. P. aeruginosa with insertionally inactivated phzM or phzS developed pyocyanin-deficient phenotypes. A third phenazine-modifying gene, phzH, which has a homologue in Pseudomonas chlororaphis, also was identified and was shown to control synthesis of phenazine-1-carboxamide from PCA in P. aeruginosa PAO1. Our results suggest that there is a complex pyocyanin biosynthetic pathway in P. aeruginosa consisting of two core loci responsible for synthesis of PCA and three additional genes encoding unique enzymes involved in the conversion of PCA to pyocyanin, 1-hydroxyphenazine, and phenazine-1-carboxamide. PMID:11591691

  9. Glyphosate-Induced Specific and Widespread Perturbations in the Metabolome of Soil Pseudomonas Species

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    Ludmilla Aristilde

    2017-06-01

    Full Text Available Previous studies have reported adverse effects of glyphosate on crop-beneficial soil bacterial species, including several soil Pseudomonas species. Of particular interest is the elucidation of the metabolic consequences of glyphosate toxicity in these species. Here we investigated the growth and metabolic responses of soil Pseudomonas species grown on succinate, a common root exudate, and glyphosate at different concentrations. We conducted our experiments with one agricultural soil isolate, P. fluorescens RA12, and three model species, P. putida KT2440, P. putida S12, and P. protegens Pf-5. Our results demonstrated both species- and strain-dependent growth responses to glyphosate. Following exposure to a range of glyphosate concentrations (up to 5 mM, the growth rate of both P. protegens Pf-5 and P. fluorescens RA12 remained unchanged whereas the two P. putida strains exhibited from 0 to 100% growth inhibition. We employed a 13C-assisted metabolomics approach using liquid chromatography-mass spectrometry to monitor disruptions in metabolic homeostasis and fluxes. Profiling of the whole-cell metabolome captured deviations in metabolite levels involved in the tricarboxylic acid cycle, ribonucleotide biosynthesis, and protein biosynthesis. Altered metabolite levels specifically in the biosynthetic pathway of aromatic amino acids (AAs, the target of toxicity for glyphosate in plants, implied the same toxicity target in the soil bacterium. Kinetic flux experiments with 13C-labeled succinate revealed that biosynthetic fluxes of the aromatic AAs were not inhibited in P. fluorescens Pf-5 in the presence of low and high glyphosate doses but these fluxes were inhibited by up to 60% in P. putida KT2440, even at sub-lethal glyphosate exposure. Notably, the greatest inhibition was found for the aromatic AA tryptophan, an important precursor to secondary metabolites. When the growth medium was supplemented with aromatic AAs, P. putida S12 exposed to a lethal

  10. Changing epidemiology of bacteremia in infants aged 1 week to 3 months.

    Science.gov (United States)

    Greenhow, Tara L; Hung, Yun-Yi; Herz, Arnd M

    2012-03-01

    Bacteremia in young infants has remained an important ongoing concern for decades. Despite changes in prenatal screening and infant immunizations, the current epidemiology of this problem has received little attention. We conducted a retrospective analysis of all blood cultures collected at Kaiser Permanente Northern California on full-term, previously healthy infants presenting for care between 1 week to 3 months of age for whom a blood culture was drawn from January 1, 2005, through December 31, 2009. During the study period, 4255 blood cultures were collected from 160 818 full-term infants. Only 2% of all blood cultures were positive for pathogens (93/4255), whereas 247 positive cultures were due to contaminants. The incidence rate of true bacteremia was 0.57 in 1000 full-term births. The most common pathogen was Escherichia coli (56%). Ninety-eight percent of infants with E coli bacteremia had a urinary tract infection. Group B Streptococcus and Staphylococcus aureus were the second and third most common pathogens, respectively. There were no cases of Listeria monocytogenes bacteremia or meningococcemia and only 1 case of enterococcal bacteremia. Ampicillin resistant pathogens accounted for 36% of organisms. Our study indicates bacteremia in young infants occurs infrequently and in only 2.2% of those who had a blood culture drawn. On the basis of the epidemiology of pathogens found in this large cohort, these data suggest a change in currently recommended presumptive antibiotic coverage in 1-week to 3-month-old infants with suspected bacteremia.

  11. Use of rifampin in persistent coagulase negative staphylococcal bacteremia in neonates

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    Walther Frans J

    2010-11-01

    Full Text Available Abstract Background Coagulase negative staphylococci (CoNS are the most common cause of neonatal sepsis in the Neonatal Intensive Care Unit (NICU. A minority of neonates does not respond to vancomycin therapy and develops persistent bacteremia, which may be treated with rifampin. We evaluated the use of rifampin in persistent CoNS bacteremia. Methods Retrospective study of 137 neonates with CoNS bacteremia during admission to a tertiary NICU between July 2006 and July 2009. Main outcome measures were total duration of bacteremia and the adequacy of vancomycin and rifampin therapy. Results 137/1696 (8.0% neonates developed a CoNS bacteremia. Eighteen were treated with rifampin because of persistent bacteremia (3 positive blood cultures at least 48 hours apart with clinical symptoms or (a serious suspicion of an intravascular thrombus. Duration of bacteremia prior to rifampin therapy (8.0 ± 3.6 days was positively correlated (p Conclusion Rifampin may be effective in the treatment of persistent CoNS infections in neonates. Outcome may be improved by adequate monitoring of vancomycin trough levels.

  12. Structure-function relationship of flavoproteins : with special reference to p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens

    NARCIS (Netherlands)

    Berkel, van W.J.H.

    1989-01-01

    In this thesis different studies probing the structurefunction relationship of some flavoproteins are dealt with. The attention has been focused on two central themes:
    The first part of the thesis deals with studies concerning the application of affinity

  13. Protozoan-induced regulation of cyclic lipopeptide biosynthesis Is an effective predation defense mechanism for Pseudomonas fluorescens

    NARCIS (Netherlands)

    Mazzola, M.; Bruijn, de I.; Cohen, M.F.; Raaijmakers, J.M.

    2009-01-01

    Environmental bacteria are exposed to a myriad of biotic interactions that influence their function and survival. The grazing activity of protozoan predators significantly impacts the dynamics, diversification, and evolution of bacterial communities in soil ecosystems. To evade protozoan predation,

  14. Remote transient Lactobacillus animalis bacteremia causing prosthetic hip joint infection: a case report

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    R. Somayaji

    2016-11-01

    Full Text Available Abstract Background Lactobacillus spp. are uncommon pathogens in immunocompetent hosts, and even rarer causes of prosthetic device infections. Case presentation A case of chronic hip prosthetic joint infection (PJI caused by L. animalis is described. This occurred 5 years after a transient bacteremia with the same organism. Whole genome sequencing of both isolates proved this PJI infection resulted from this remote bacteremia. Conclusions We document that prosthetic joint infections may be a consequence of bacteremia as much as 3 years before the onset of symptoms.

  15. Multidrug-resistant Gram-negative bacteria in solid organ transplant recipients with bacteremias.

    Science.gov (United States)

    Wan, Q Q; Ye, Q F; Yuan, H

    2015-03-01

    Bloodstream infections (BSIs) remain as life-threatening complications and are associated with significant morbidity and mortality among solid organ transplant (SOT) recipients. Multidrug-resistant (MDR) Gram-negative bacteria can cause serious bacteremias in these recipients. Reviews have aimed to investigate MDR Gram-negative bacteremias; however, they were lacking in SOT recipients in the past. To better understand the characteristics of bacteremias due to MDR Gram-negative bacteria, optimize preventive and therapeutic strategies, and improve the outcomes of SOT recipients, this review summarize the epidemiology, clinical and laboratory characteristics, and explores the mechanisms, prevention, and treatment of MDR Gram-negative bacteria.

  16. Highly drug-resistant pathogens implicated in burn-associated bacteremia in an Iraqi burn care unit.

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    Jean-Baptiste Ronat

    Full Text Available OBJECTIVE: In low- and middle-income countries, bloodstream infections are an important cause of mortality in patients with burns. Increasingly implicated in burn-associated infections are highly drug-resistant pathogens with limited treatment options. We describe the epidemiology of bloodstream infections in patients with burns in a humanitarian surgery project in Iraq. METHODS: We performed a retrospective, descriptive study of blood culture isolates identified between July 2008 and September 2009 among patients with burns in a single hospital in Iraq who developed sepsis. RESULTS: In 1169 inpatients admitted to the burn unit during the study period, 212 (18% had suspected sepsis, and 65 (6% had confirmed bacteremia. Sepsis was considered the primary cause of death in 198 patients (65%; 95% CI 65-70 of the 304 patients that died. The most commonly isolated organisms were Pseudomonas aeruginosa (22 isolates [34%], Staphylococcus aureus (17 [26%], Klebsiella pneumoniae (8 [12%], Staphylococcus epidermidis (7 [11%], Acinetobacter baumannii (6 [9%], and Enterobacter cloacae (5 [8%]. A high proportion of Enterobacteriaceae strains produced extended-spectrum beta-lactamase and S. aureus isolates were uniformly methicillin-resistant. For gram-negative bacteria, the most reliably active antibiotics were imipenen and amikacin. CONCLUSIONS: Burn patients with sepsis in Iraq were commonly found to have bloodstream pathogens resistant to most antibiotics available locally. Effective empirical therapy of burn sepsis in this region of Iraq would consist of vancomycin or teicoplanin and a carbapenem-class antibiotic with antipseudomonal activity.

  17. Bacteremias em pacientes internados em hospital universitário Bacteremias at a teaching hospital: etiology, antimicrobial susceptibiliy pattern and risk factors for mortality

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    Adriana Oliveira Guilarde

    2007-02-01

    Full Text Available OBJETIVO: Avaliar a incidência de bacteremias, seu perfil de suscetibilidade antimicrobiana, e fatores associados ao óbito, em hospital universitário, no período de 1º de janeiro de 2000 a 31 de dezembro de 2001. MÉTODOS: Coorte retrospectiva. Pacientes maiores de 1 ano de idade, com bacteremia laboratorialmente confirmada e clinicamente significativa foram incluídos no estudo. Realizada análise de sobrevida multivariada, seguindo o modelo de riscos proporcionais de Cox. RESULTADOS: Foram detectados 295 episódios de bacteremia. O patógeno mais freqüente foi o Staphylococcus aureus: 118 (40%, com 55,9% de MRSA. A letalidade pela bacteremia foi de 34,5%. Os fatores de risco independentes para o óbito foram terapia inicial inadequada (HR ajustado 2,05 IC 95%: 1,25-3,36 e gravidade da apresentação clínica (HR ajustado 5,52 IC 95%: 3,15-9,69. CONCLUSÃO: Nosso estudo mostrou elevada letalidade associada a bacteremia, com alta freqüência de MRSA. A terapia inicial inadequada e a gravidade da apresentação clínica foram fatores de risco independentes para o óbito pela bacteremia.OBJECTIVE: To evaluate the frequency and profile of bacteremia, its antimicrobial susceptibility and to analyze predictors of mortality in bloodstream infections (BSI at this Teaching Hospital from January 1, 2000 to December 31, 2001. METHODS: Design: retrospective cohort. Patients over one year old with clinically significant episodes of BSI which were microbiologically documented were included in the study. The Cox proportional hazards risk model was applied to identify prognostic factors related to death by bacteremia. RESULTS: A total of 295 episodes of BSI were detected. The most common pathogen was S. aureus: 118 (40.0%, with 55.9% of MRSA. Mortality associated with bacteremia was 34.5%. Independent predictors of mortality were: inadequate initial therapy (HR adjusted 2.05 IC95%: 1.25-3.36 and severity of the clinical manifestations (HR adjusted 5

  18. Bartonella spp. bacteremia in blood donors from Campinas, Brazil.

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    Luiza Helena Urso Pitassi

    2015-01-01

    Full Text Available Bartonella species are blood-borne, re-emerging organisms, capable of causing prolonged infection with diverse disease manifestations, from asymptomatic bacteremia to chronic debilitating disease and death. This pathogen can survive for over a month in stored blood. However, its prevalence among blood donors is unknown, and screening of blood supplies for this pathogen is not routinely performed. We investigated Bartonella spp. prevalence in 500 blood donors from Campinas, Brazil, based on a cross-sectional design. Blood samples were inoculated into an enrichment liquid growth medium and sub-inoculated onto blood agar. Liquid culture samples and Gram-negative isolates were tested using a genus specific ITS PCR with amplicons sequenced for species identification. Bartonella henselae and Bartonella quintana antibodies were assayed by indirect immunofluorescence. B. henselae was isolated from six donors (1.2%. Sixteen donors (3.2% were Bartonella-PCR positive after culture in liquid or on solid media, with 15 donors infected with B. henselae and one donor infected with Bartonella clarridgeiae. Antibodies against B. henselae or B. quintana were found in 16% and 32% of 500 blood donors, respectively. Serology was not associated with infection, with only three of 16 Bartonella-infected subjects seropositive for B. henselae or B. quintana. Bartonella DNA was present in the bloodstream of approximately one out of 30 donors from a major blood bank in South America. Negative serology does not rule out Bartonella spp. infection in healthy subjects. Using a combination of liquid and solid cultures, PCR, and DNA sequencing, this study documents for the first time that Bartonella spp. bacteremia occurs in asymptomatic blood donors. Our findings support further evaluation of Bartonella spp. transmission which can occur through blood transfusions.

  19. [Significant bacteremias by Corynebacterium amycolatum: an emergent pathogen].

    Science.gov (United States)

    Oteo, J; Aracil, B; Ignacio Alós, J; Luis Gómez-Garcés, J

    2001-03-01

    Corynebacterium sp. is an extremely varied genus which includes little known species and of which only Corynebacterium diphteriae, Corynebacterium urealyticum and Corynebacterium jeikeium are considered indisputable pathogens. Other species, such as C. amycolatum are at present being reconsidered as causative agents in infectious pathologies, partly on account of our greater aquaintance and improved identification techniques for these microorganisms and partly on account of the growing number of immunocompromised patients in whom all their pathogenic capacity is usually able to develope. We present 3 cases of significant bacteremia by C. amycolatum. Bacterial isoliations from blood culture were obtained using the Vital Systems. Identification was performed by means of Gran stain, colony morphology, the results of numerous biochemical tests (including the Api Coryne systems), the behaviour of the strains against the vibriostatic agent O/129 and the antibiotic susceptibility pattern obtained with the E-test. The three isolates of C. amycolatum were obtained from patients after a lenghtly hospitalization, multi-instrumentation and who had severe underlying disease. All three presented with concomitant isolates of C. amycolatum from other sites: sputum, wound and catheter respectively, which could explain the origin of the bacteremia. Colony morphology, antibiotic susceptibility patterns, resistance to the vibriostatic agent O/129 and the results of the biochemical test carried out were similar to those previously describe in the literature. C. amycolatum should be born in mind as a agent responsable for significant and severe pathology in this type of patient. In addition, it as certain specific characteristics which assits in its identification in the normal micr

  20. Polytrauma Increases Susceptibility to Pseudomonas Pneumonia in Mature Mice.

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    Turnbull, Isaiah R; Ghosh, Sarbani; Fuchs, Anja; Hilliard, Julia; Davis, Christopher G; Bochicchio, Grant V; Southard, Robert E

    2016-05-01

    Pneumonia is the most common complication observed in patients with severe injuries. Although the average age of injured patients is 47 years, existing studies of the effect of injury on the susceptibility to infectious complications have focused on young animals, equivalent to a late adolescent human. We hypothesized that mature adult animals are more susceptible to infection after injury than younger counterparts. To test this hypothesis, we challenged 6 to 8-month-old mature mice to a polytrauma injury followed by Pseudomonas aeruginosa pneumonia and compared them to young (8-10-week-old) animals. We demonstrate that polytrauma injury increases mortality from pneumonia in mature animals (sham-pneumonia 21% vs. polytrauma-pneumonia 62%) but not younger counterparts. After polytrauma, pneumonia in mature mice is associated with higher bacterial burden in lung, increased incidence of bacteremia, and elevated levels of bacteria in the blood, demonstrating that injury decreases the ability to control the infectious challenge. We further find that polytrauma did not induce elevations in circulating cytokine levels (TNF-alpha, IL-6, KC, and IL-10) 24  h after injury. However, mature mice subjected to polytrauma demonstrated an exaggerated circulating inflammatory cytokine response to subsequent Pseudomonas pneumonia. Additionally, whereas prior injury increases LPS-stimulated IL-6 production by peripheral blood leukocytes from young (8-10-week-old) mice, injury does not prime IL-6 production by cell from mature adult mice. We conclude that in mature mice polytrauma results in increased susceptibility to Pseudomonas pneumonia while priming an exaggerated but ineffective inflammatory response.

  1. Pseudomonas cichorii as the causal agent of midrib rot, an emerging disease of greenhouse-grown butterhead lettuce in Flanders.

    Science.gov (United States)

    Cottyn, Bart; Heylen, Kim; Heyrman, Jeroen; Vanhouteghem, Katrien; Pauwelyn, Ellen; Bleyaert, Peter; Van Vaerenbergh, Johan; Höfte, Monica; De Vos, Paul; Maes, Martine

    2009-05-01

    Bacterial midrib rot of greenhouse-grown butterhead lettuce (Lactuca sativa L. var. capitata) is an emerging disease in Flanders (Belgium) and fluorescent pseudomonads are suspected to play an important role in the disease. Isolations from infected lettuces, collected from 14 commercial greenhouses in Flanders, yielded 149 isolates that were characterized polyphasically, which included morphological characteristics, pigmentation, pathogenicity tests by both injection and spraying of lettuce, LOPAT characteristics, FAME analysis, BOX-PCR fingerprinting, 16S rRNA and rpoB gene sequencing, as well as DNA-DNA hybridization. Ninety-eight isolates (66%) exhibited a fluorescent pigmentation and were associated with the genus Pseudomonas. Fifty-five of them induced an HR+ (hypersensitive reaction in tobacco leaves) response. The other 43 fluorescent isolates were most probably saprophytic bacteria and about half of them were able to cause rot on potato tuber slices. BOX-PCR genomic fingerprinting was used to assess the genetic diversity of the Pseudomonas midrib rot isolates. The delineated BOX-PCR patterns matched quite well with Pseudomonas morphotypes defined on the basis of colony appearance and variation in fluorescent pigmentation. 16S rRNA and rpoB gene sequence analyses allowed most of the fluorescent isolates to be allocated to Pseudomonas, and they belonged to either the Pseudomonas fluorescens group, Pseudomonas putida group, or the Pseudomonas cichorii/syringae group. In particular, the isolates allocated to this latter group constituted the vast majority of HR+ isolates and were identified as P. cichorii by DNA-DNA hybridization. They were demonstrated by spray-inoculation tests on greenhouse-grown lettuce to induce the midrib rot disease and could be re-isolated from lesions of inoculated plants. Four HR+ non-fluorescent isolates associated with one sample that showed an atypical midrib rot were identified as Dickeya sp.

  2. Organic acid production in vitro and plant growth promotion in maize under controlled environment by phosphate-solubilizing fluorescent Pseudomonas

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    Vyas Pratibha

    2009-08-01

    Full Text Available Abstract Background Phosphorus deficiency is a major constraint to crop production due to rapid binding of the applied phosphorus into fixed forms not available to the plants. Microbial solubilization of inorganic phosphates has been attributed mainly to the production of organic acids. Phosphate-solubilizing microorganisms enhance plant growth under conditions of poor phosphorus availability by solubilizing insoluble phosphates in the soil. This paper describes the production of organic acids during inorganic phosphate solubilization and influence on plant growth as a function of phosphate solubilization by fluorescent Pseudomonas. Results Nineteen phosphate-solubilizing fluorescent Pseudomonas strains of P. fluorescens, P. poae, P. trivialis, and Pseudomonas spp. produced gluconic acid, oxalic acid, 2-ketogluconic acid, lactic acid, succinic acid, formic acid, citric acid and malic acid in the culture filtrates during the solubilization of tricalcium phosphate, Mussoorie rock phosphate, Udaipur rock phosphate and North Carolina rock phosphate. The strains differed quantitatively and qualitatively in the production of organic acids during solubilization of phosphate substrates. Cluster analysis based on organic acid profiling revealed inter-species and intra-species variation in organic acids produced by Pseudomonas strains. The phosphate-solubilizing bacterial treatments P. trivialis BIHB 745, P. trivialis BIHB 747, Pseudomonas sp. BIHB 756 and P. poae BIHB 808 resulted in significantly higher or statistically at par growth and total N, P and K content over single super phosphate treatment in maize. These treatments also significantly affected pH, organic matter, and N, P, and K content of the soil. Conclusion The results implied that organic acid production by Pseudomonas strains is independent of their genetic relatedness and each strain has its own ability of producing organic acids during the solubilization of inorganic phosphates

  3. Organic acid production in vitro and plant growth promotion in maize under controlled environment by phosphate-solubilizing fluorescent Pseudomonas.

    Science.gov (United States)

    Vyas, Pratibha; Gulati, Arvind

    2009-08-22

    Phosphorus deficiency is a major constraint to crop production due to rapid binding of the applied phosphorus into fixed forms not available to the plants. Microbial solubilization of inorganic phosphates has been attributed mainly to the production of organic acids. Phosphate-solubilizing microorganisms enhance plant growth under conditions of poor phosphorus availability by solubilizing insoluble phosphates in the soil. This paper describes the production of organic acids during inorganic phosphate solubilization and influence on plant growth as a function of phosphate solubilization by fluorescent Pseudomonas. Nineteen phosphate-solubilizing fluorescent Pseudomonas strains of P. fluorescens, P. poae, P. trivialis, and Pseudomonas spp. produced gluconic acid, oxalic acid, 2-ketogluconic acid, lactic acid, succinic acid, formic acid, citric acid and malic acid in the culture filtrates during the solubilization of tricalcium phosphate, Mussoorie rock phosphate, Udaipur rock phosphate and North Carolina rock phosphate. The strains differed quantitatively and qualitatively in the production of organic acids during solubilization of phosphate substrates. Cluster analysis based on organic acid profiling revealed inter-species and intra-species variation in organic acids produced by Pseudomonas strains. The phosphate-solubilizing bacterial treatments P. trivialis BIHB 745, P. trivialis BIHB 747, Pseudomonas sp. BIHB 756 and P. poae BIHB 808 resulted in significantly higher or statistically at par growth and total N, P and K content over single super phosphate treatment in maize. These treatments also significantly affected pH, organic matter, and N, P, and K content of the soil. The results implied that organic acid production by Pseudomonas strains is independent of their genetic relatedness and each strain has its own ability of producing organic acids during the solubilization of inorganic phosphates. Significant difference in plant growth promotion by efficient

  4. Arsenic-contaminated soils. Genetically modified Pseudomonas spp. and their arsenic-phytoremediation potential

    Energy Technology Data Exchange (ETDEWEB)

    Sizova, O.I.; Kochetkov, V.V.; Validov, S.Z.; Boronin, A.M. [Inst. of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Moscow (Russian Federation); Kosterin, P.V.; Lyubun, Y.V. [Inst. of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Saratov (Russian Federation)

    2002-07-01

    Sorghum was inoculated with Pseudomonas bacteria, including strains harboring an As-resistance plasmid, pBS3031, to enhance As-extraction by the plants. Pseudomonas strains (P. fluorescens 38a, P. putida 53a, and P. aureofaciens BS1393) were chosen because they are antagonistic to a wide range of phytopathogenic fungi and bacteria, and they can stimulate plant growth. The resistance of natural rhizospheric pseudomonads to sodium arsenite was assessed. Genetically modified Pseudomonas strains resistant to As(III)/As(V) were obtained via conjugation or transformation. The effects of the strains on the growth of sorghum on sodium-arsenite-containing soils were assessed. The conclusions from this study are: (1) It is possible to increase the survivability of sorghum growing in sodium-arsenite-containing soil by using rhizosphere pseudomonads. (2) The presence of pBS3031 offers the strains a certain selective advantage in arsenite-contaminated soil. (3) The presence of pBS3031 impairs plant growth, due to the As-resistance mechanism determined by this plasmid: the transformation of the less toxic arsenate into the more toxic, plant-root-available arsenite by arsenate reductase and the active removal of arsenite from bacterial cells. (4) Such a mechanism makes it possible to develop a bacteria-assisted phytoremediation technology for the cleanup of As-contaminated soils and is the only possible way of removing the soil-sorbed arsenates from the environment. (orig.)

  5. Virulence Attributes and Host Response Assays for Determining Pathogenic Potential of Pseudomonas Strains Used in Biotechnology.

    Directory of Open Access Journals (Sweden)

    Azam F Tayabali

    Full Text Available Pseudomonas species are opportunistically pathogenic to humans, yet closely related species are used in biotechnology applications. In order to screen for the pathogenic potential of strains considered for biotechnology applications, several Pseudomonas strains (P.aeruginosa (Pa, P.fluorescens (Pf, P.putida (Pp, P.stutzeri (Ps were compared using functional virulence and toxicity assays. Most Pa strains and Ps grew at temperatures between 28°C and 42°C. However, Pf and Pp strains were the most antibiotic resistant, with ciprofloxacin and colistin being the most effective of those tested. No strain was haemolytic on sheep blood agar. Almost all Pa, but not other test strains, produced a pyocyanin-like chromophore, and caused cytotoxicity towards cultured human HT29 cells. Murine endotracheal exposures indicated that the laboratory reference strain, PAO1, was most persistent in the lungs. Only Pa strains induced pro-inflammatory and inflammatory responses, as measured by elevated cytokines and pulmonary Gr-1 -positive cells. Serum amyloid A was elevated at ≥ 48 h post-exposure by only some Pa strains. No relationship was observed between strains and levels of peripheral leukocytes. The species designation or isolation source may not accurately reflect pathogenic potential, since the clinical strain Pa10752 was relatively nonvirulent, but the industrial strain Pa31480 showed comparable virulence to PAO1. Functional assays involving microbial growth, cytotoxicity and murine immunological responses may be most useful for identifying problematic Pseudomonas strains being considered for biotechnology applications.

  6. The complete genome sequence of the plant growth-promoting bacterium Pseudomonas sp. UW4.

    Directory of Open Access Journals (Sweden)

    Jin Duan

    Full Text Available The plant growth-promoting bacterium (PGPB Pseudomonas sp. UW4, previously isolated from the rhizosphere of common reeds growing on the campus of the University of Waterloo, promotes plant growth in the presence of different environmental stresses, such as flooding, high concentrations of salt, cold, heavy metals, drought and phytopathogens. In this work, the genome sequence of UW4 was obtained by pyrosequencing and the gaps between the contigs were closed by directed PCR. The P. sp. UW4 genome contains a single circular chromosome that is 6,183,388 bp with a 60.05% G+C content. The bacterial genome contains 5,423 predicted protein-coding sequences that occupy 87.2% of the genome. Nineteen genomic islands (GIs were predicted and thirty one complete putative insertion sequences were identified. Genes potentially involved in plant growth promotion such as indole-3-acetic acid (IAA biosynthesis, trehalose production, siderophore production, acetoin synthesis, and phosphate solubilization were determined. Moreover, genes that contribute to the environmental fitness of UW4 were also observed including genes responsible for heavy metal resistance such as nickel, copper, cadmium, zinc, molybdate, cobalt, arsenate, and chromate. Whole-genome comparison with other completely sequenced Pseudomonas strains and phylogeny of four concatenated "housekeeping" genes (16S rRNA, gyrB, rpoB and rpoD of 128 Pseudomonas strains revealed that UW4 belongs to the fluorescens group, jessenii subgroup.

  7. C-reactive protein level as a predictor of mortality in liver disease patients with bacteremia

    DEFF Research Database (Denmark)

    Janum, Sine H; Søvsø, Morten; Gradel, Kim O

    2011-01-01

    Abstract Background and objective. C-reactive protein (CRP) is synthesized in the liver in response to inflammation, and CRP is a widely used marker of sepsis. In bacteremia the initial CRP level is an independent predictor of mortality. Since the CRP response in patients with chronic liver disease...... is lower than in patients without liver disease the objective was to assess whether CRP levels in chronic liver disease and bacteremia was associated with case fatality. Patients. The study enrolled 105 patients with chronic liver disease and bacteremia as well as 202 patients with bacteremia...... was significantly higher in patients with chronic liver disease (mortality rate ratio 2.2; 95% confidence interval 1.2-3.9) and it was correlated to Child-Turcotte-Pugh scores. CRP levels were not different between the three Child-Turcotte-Pugh classes (p = 0.33), and no linear correlation with 30-day mortality...

  8. Gram-negative rod bacteremia after cardiovascular surgery: Clinical features and prognostic factors

    Directory of Open Access Journals (Sweden)

    Sayaka Tago

    2017-06-01

    Conclusion: Graft replacement was the most common surgical procedure in patients with GNRB after CVS. Empirical antibiotics covering Gram-negative rods including P. aeruginosa should be considered if bacteremia is suspected in unstable patients after CVS.

  9. Gastrointestinal stromal tumor complicated by Streptococcus milleri bacteremia and liver abscess.

    Science.gov (United States)

    Kwon, Yong; Dang, Ngoc-Duyen T; Elmunzer, Badih Joseph

    2009-07-01

    Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. Often discovered incidentally, GISTs can present with nonspecific abdominal symptoms or more overt symptoms of bleeding, obstruction, or perforation. Despite a myriad of clinical presentations, bacteremia associated with a GIST has not been described. In this report, we present an unusual clinical case that illustrates how GISTs can become infected, and demonstrate the importance of Streptococcus milleri bacteremia as an indicator of possible underlying gastrointestinal neoplasm.

  10. Nosocomial bacteremia due to Kluyvera cryocrescens: Case report and literature review

    Directory of Open Access Journals (Sweden)

    Yusuke Yoshino

    2016-01-01

    Piperacilin/tazobactam was administered for 2 weeks and the bacteremia resolved. Unfortunately, there was acute exacerbation of the interstitial lung disease, which was fatal. According to our review, including our case, K. cryocrescens bacteremia tends to occur in immunocompromised hosts, and indwelling catheters might be risk factors. Extended spectrum cephalosporins, carbapenems, fluoroquinolones and tetracyclines are generally adequate agents for empiric therapy based on susceptibilities of K. cryocrescens clinical isolates.

  11. Molecular epidemiological characteristics of Klebsiella pneumoniae associated with bacteremia among patients with pneumonia.

    Science.gov (United States)

    Ito, Ryota; Shindo, Yuichiro; Kobayashi, Daisuke; Ando, Masahiko; Jin, Wanchun; Wachino, Jun-ichi; Yamada, Keiko; Kimura, Kouji; Yagi, Tetsuya; Hasegawa, Yoshinori; Arakawa, Yoshichika

    2015-03-01

    Some important virulence factors have been elucidated in Klebsiella pneumoniae infections. We investigated the relationship between virulence factors and multilocus sequence types (STs) and assessed the risk factors for bacteremia in patients with pneumonia due to K. pneumoniae. From April 2004 through April 2012, a total of 120 K. pneumoniae isolates from patients with pneumonia (23 with bacteremia and 97 without bacteremia) were collected from 10 medical institutions in Japan. Additionally, 10 strains of K. pneumoniae serotype K2 that were isolated >30 years ago were included in this study. These isolates were characterized using multilocus sequence typing (MLST), and the characteristics of their virulence factors, such as hypermucoviscosity phenotype and RmpA and aerobactin production between patients with and without bacteremia, were examined. MLST analysis was performed on the 120 isolates from patients with pneumonia, and some sequence type groups were defined as genetic lineages (GLs). GL65 was more prevalent among patients with bacteremia (21.7%) than in those without bacteremia (7.2%). The majority of the strains with serotype K2 were classified into GL14 or GL65, and rmpA and the gene for aerobactin were present in all GL65-K2 strains but absent in all GL14-K2 strains. In a multivariate analysis, the independent risk factors for bacteremia included GL65 (adjusted odds ratio [AOR], 9.46; 95% confidence interval [CI], 1.81 to 49.31), as well as neoplastic disease (AOR, 9.94; 95% CI, 2.61 to 37.92), immunosuppression (AOR, 17.85; 95% CI, 1.49 to 214.17), and hypoalbuminemia (AOR, 4.76; 95% CI, 1.29 to 17.61). GL65 was more prevalent among patients with bacteremia and was associated with the virulence factors of K. pneumoniae. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  12. Actinomyces urogenitalis bacteremia and tubo-ovarian abscess after an in vitro fertilization (IVF) procedure.

    Science.gov (United States)

    Van Hoecke, Frederik; Beuckelaers, Ellen; Lissens, Peter; Boudewijns, Michael

    2013-12-01

    We describe the first case of bacteremia due to Actinomyces urogenitalis. Bacteremia was secondary to a tubo-ovarian abscess following transvaginal oocyte retrieval. Identification was established by matrix-assisted desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and confirmed by 16S rRNA gene sequencing. A. urogenitalis should be considered as a potential causative agent of infection after gynecological procedures.

  13. Recurrent bacteremia with different strains of Streptococcus pyogenes in an immunocompromised child.

    Science.gov (United States)

    Hattori, Takuya; Minami, Masaaki; Narita, Kotaro; Nakata, Tomohiko; Itomi, Seiko; Kubota, Kinya; Oya, Teruaki; Nishiyama, Hideki; Kato, Hideki; Yuasa, Norihiro

    2016-06-01

    We report an immunocompromised child who experienced two episodes of bacteremia due to Streptococcus pyogenes. Random amplification of polymorphic DNA profiles, emm genotypes, superantigen profiles, antimicrobial susceptibility, and resistance-related genes were investigated, and the results showed different profiles between the two isolates. This is the first report describing recurrent bacteremia caused by different strains of S. pyogenes. Copyright © 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  14. Commensal Pseudomonas Species Isolated from Wastewater and Freshwater Milieus in the Eastern Cape Province, South Africa, as Reservoir of Antibiotic Resistant Determinants

    Directory of Open Access Journals (Sweden)

    Anthony I. Okoh

    2012-07-01

    Full Text Available Pseudomonas species are opportunistic pathogens with implications in a wide range of diseases including cystic fibrosis and sickle cell anaemia. Because of their status as multidrug resistant (MDR and extremely drug resistant (XDR bacteria Pseudomonas species represent a threat to public health. Prevalence, antibiogram and associated antibiotic resistant genes of Pseudomonas species isolated from freshwater and mixed liquor environments in the Eastern Cape Province of South Africa were assessed. Polymerase chain reaction (PCR based technique was used to identify the isolates and screen for antibiotic resistant genes. The result shows occurrence of Pseudomonas spp. in freshwater and mixed liquor as follows: 71.42% and 37.5% (P. putida, 14.28% and 31.25% (P. flourescens, 7.14% and 6.25% (P. aeruginosa and 7.14% and 25% for other Pseudomonas species respectively. Disk diffusion antibiogram of the Pseudomonas isolates from the two locations showed 100% resistance to penicillin, oxacillin, clindamycin, rifampicin and 100% susceptibility to ciprofloxacin and gentamicin with varied percentage resistances to cephalothin, nalidixic acid, tetracycline, and ampicillin. The blaTEM antibiotic resistant gene was detected in 12.5% of P. putida, 57.14% of P. fluorescens, 100% P. aeruginosa and 40% in other Pseudomonas species. Similarly, Integrons conserved segment were detected in 12.5% of P. putida, 57.14% of P. fluorescens, 100% of P. aeruginosa and 40% of other Pseudomonas species. The presence of blaTEM gene and integrons conserved segment in some of the isolates is worrisome and suggest Pseudomonas species as important reservoirs of multidrug resistance genes in the Eastern Cape Province environment.

  15. Evaluation of the incidence of occult bacteremia among children with fever of unknown origin

    Directory of Open Access Journals (Sweden)

    Eitan Naaman Berezin

    Full Text Available We reviewed the incidence of occult bacteremia, to identify the most frequent etiological agents of bacteremias in otherwise healthy children from one month to 10 years old, who had fever of unknown origin attended at the emergency ward of an urban, university-affiliated pediatric referral center. This was a retrospective medical record review, evaluating children with fever. Data were collected from the initial visit, when blood cultures, hematological properties and hemosedimentation rates were examined. Fever was considered as the highest temperature assessed in the hospital or reported by the responsible adult. Occult bacteremia was discovered in 1.4% of the 1,051 children evaluated, and the most common etiologic agent was Streptococcus pneumoniae. Total leukocyte count and blood sedimentation rates greater than 30 mm³ were not predictive factors for occult bacteremia. Fever greater than 39ºC was the most important factor for predicting occult bacteremia (P<0.001. The presence of occult bacteremia was significantly correlated with patient hospitalization.

  16. Computer-assisted flapless implant placement reduces the incidence of surgery-related bacteremia.

    Science.gov (United States)

    Arısan, Volkan; Bölükbaşı, Nilüfer; Öksüz, Lütfiye

    2013-12-01

    Bacteremia--the access of bacterium to the bloodstream--may yield life-threatening complications. The aim of this study was to compare the incidence, duration, and type of bacterium leading to bacteremia with relation to conventional and computer-assisted flapless implant surgery. A total of 377 implants were placed in 68 edentulous jaws using the conventional (conventional group) or a computer-assisted stereolithographic (SLA) template-guided surgery technique (flapless group). Bacteremia was monitored from pre- and postoperative blood samples. The duration of the surgical intervention was significantly shorter in the flapless group (p = 0.3510). Baseline samples were sterile. Following the 15th minute after the placement of the last implant, bacteria were present in 62 and 12 % of the patients in the conventional and flapless groups, respectively (p flapless group. Staphylocccus epidermidis, Bifidobacterium spp., Streptococcus viridans, Corynebacterium spp., and Streptococcus sanguinis were the isolated bacterium. Irrespective of the utilized technique, bacteremia may occur upon the placement of four to eight implants to an edentulous jaw. The probability of bacteremia for the patients operated with the conventional technique is, however, 3.05 greater than those operated with the flapless technique. Flapless implant placement reduces the incidence of surgery-related bacteremia and, therefore, may be beneficial to patients at risk.

  17. Incidence of oral indigenous bacteria in causative strains isolated from blood cultures in 759 laboratory-confirmed cases of bacteremia

    OpenAIRE

    Shinya Yura; Sadaya Matano

    2012-01-01

    Background: The incidence of oral indigenous bacteria in cases of bacteremia has been reported in only a few studies. We investigated the annual incidence of oral indigenous bacteria isolated in blood cultures from patients with bacteremia and call into consideration the impact of oral health measures implemented at our facility. Methods: In the period from 2001 to 2006, 759 laboratory-confirmed cases of bacteremia were reported and subsequently analyzed in this study. The incidences of the c...

  18. Population Structure of Pseudomonas aeruginosa

    National Research Council Canada - National Science Library

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

    2007-01-01

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

  19. Bacteremia and other body site infection caused by hypervirulent and classic Klebsiella pneumoniae.

    Science.gov (United States)

    Wu, Hua; Li, Dongdong; Zhou, Haijian; Sun, Yunfang; Guo, Ling; Shen, Dingxia

    2017-03-01

    To investigate bacteremia and other body site infection caused by hypervirulent Klebsiella pneumoniae (hvKP), a recently recognized pathogen of invasive infection, and classic Klebsiella pneumoniae (cKP), a very common organism associated with many kinds of nosocomial infection. Clinical information obtained from patients with both bacteremia and other body site infections caused by hvKP and/or cKP was retrospectively reviewed. Homo-hvKP (or homo-cKP) was defined as homologous hvKP (or cKP) strains from different body sites in each individual patient according to string test, virulence gene amplification and PFGE pattern. MLST was carried on to understand the correlation of sequence type with capsular polysaccharide type for Klebsiella pneumoniae from blood. Sixty-four hvKP and 101 cKP strains were isolated from blood and other body sites of 76 patients who had bacteremia accompanied by other site infection. Among these patients, 27 were infected with homo-hvKP, 32 were with homo-cKP, 12 were with heterogeneous cKP, and five were with both hvKP and cKP. Patients with bacteremia and liver abscesses caused by homo-hvKP accounted for 51.9%, and 92.6% of homo-hvKP infected patients did not receive any invasive procedures before bacteremia. However, patients with bacteremia and biliary tract infection caused by homo-cKP accounted for 34.4%, and 78.1% of homo-cKP infected patients had history of invasive procedures before bacteremia. More homo-hvKP strains (59.3%) than homo-cKP strains (34.4%) were isolated from blood earlier than other sites. HvKP strains were statistically more susceptible to the tested antimicrobials than cKP strains. An outbreak of carbapenem-resistant cKP infection and possible gene transfer of KPC-2 from cKP to hvKP were brought to notice. Both hvKP and cKP could cause bacteremia and other body site infection. But patients with hvKP bacteremia usually suffered from liver abscess without previous invasive procedures, most patients with c

  20. Risk factors and microbiology of meningitis and/or bacteremia after transsphenoidal surgery for pituitary adenoma.

    Science.gov (United States)

    Jin, Yu; Liu, Xiaohai; Gao, Lu; Guo, Xiaopeng; Wang, Qiang; Bao, Xinjie; Deng, Kan; Yao, Yong; Feng, Ming; Lian, Wei; Wang, Renzhi; Yang, Qiwen; Wang, Yao; Xing, Bing

    2017-11-27

    To investigate the incidence, bacteriological features, and risk factors of post- transsphenoidal surgery (TSS) meningitis and/or bacteremia. This retrospective study included 3242 patients who underwent TSS for pituitary adenoma at the Dept. of Neurosurgery of Peking Union Medical College Hospital between January 2012 and December 2016. Clinical data for patients with and without post-TSS meningitis and/or bacteremia were compared and analyzed. Meningitis and bacteremia developed after 27 (0.8%) and 26 (0.8%) procedures, respectively, and six patients (0.2%) developed both. Gram-positive organisms (coagulase-negative staphylococci, Streptococcus (S.) pneumonia, and S. viridans) predominated in meningitis, whereas gram-negative organisms (K. pneumonia, E. aerogenes, and E. coli) predominated in bacteremia. All identified species were sensitive to amikacin, imipenem and meropenem. Antibiotic treatment cured 52 patients (seven died). In a multivariate analysis, the risk of meningitis and/or bacteremia was independently associated with diabetes (p < 0.001, OR 6.06), previous surgery at the same location (p < 0.001, OR 4.23), intraoperative CSF (Cerebrospinal Fluid) leakage (p < 0.001, OR 4.63), and an endoscopic approach (p = 0.001, OR 2.50). Meningitis and/or bacteremia remain critical postoperative complications of TSS for pituitary adenoma. The pathogens with drug-sensitivity to antibiotics differed between meningitis and bacteremia. Early blood and CSF bacterial cultures, drug susceptibility analyses, and appropriate antibiotic treatment can help control the rate of infection. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Antimicrobial activity of gallic acid against food-related Pseudomonas strains and its use as biocontrol tool to improve the shelf life of fresh black truffles.

    Science.gov (United States)

    Sorrentino, Elena; Succi, Mariantonietta; Tipaldi, Luca; Pannella, Gianfranco; Maiuro, Lucia; Sturchio, Marina; Coppola, Raffaele; Tremonte, Patrizio

    2018-02-02

    Refrigeration alone or in combination with other technologies represents the main tool used in the last decades to preserve the freshness of black truffles. This is principally due to the delicateness and vulnerability of this edible hypogeous fungus, so that other invasive preservation practices cannot be adopted. However, the proliferation of some microbial species during the cold storage still represents an unsolved problem. Pseudomonads are among the main spoiler bacteria responsible for the deterioration of refrigerated black truffles. Their growth ability at low temperatures requires the use of additional hurdles to prolong the shelf-life of truffles without altering their major features. The use of natural compounds may represent an alternative system for the biocontrol of this kind of product. Specifically, gallic acid (GA) is a phenolic acid naturally present in different foods, whose effectiveness was in vitro demonstrated against Pseudomonas spp. In our study, we reported the antimicrobial activity expressed by GA not only in vitro, using as target bacteria Pseudomonas putida DSMZ 291 T , P. fluorescens DSMZ 50090 T , P. fragi DSMZ 3456 T and Pseudomonas spp. P30-4, previously isolated from black truffles, but also in situ on fresh black truffles stored at 4°C for 28days. Our results showed Minimum Inhibitory Concentrations (MIC) of 2.5mg/mL GA for all tested strains, except for P. fluorescens DSMZ 50090 T , having a MIC corresponding to 5mg/mL GA. The Minimum Bactericidal Concentration (MBC) was 10mg/mL for all strains. The analysis of kinetic parameters showed that the survival declined passing from 2.5 to 10mg/mL GA concentrations, with P. fluorescens confirmed to be the most resistant strain. Moreover, images obtained from Scanning Electron Microscopy revealed that Pseudomonas cells were strongly injured by the treatment with GA at 2.5mg/mL concentration, displaying visible pores on the cellular surfaces, absence of flagella and lysis with loss of

  2. Francisella tularensis Bacteremia: A Case Report from Sudan

    Directory of Open Access Journals (Sweden)

    Salma E. R. Mohamed

    2012-01-01

    Full Text Available Francisella tularensis is a highly virulent intracellular gram-negative bacterium. The organism is usually isolated from wild and domestic animals and invertebrate. Man gets infection by direct contact with those animals or their products but the most common mode of transmission is via arthropod vectors. The disease is endemic in North America, parts of Europe, and Asia but has never been reported in Africa. A 29-year old male living in a rural area of Southern Sudan has been maintained on continuous ambulatory peritoneal dialysis for two years. He presented to our center in May 2010 complaining of fever, dry cough, shortness of breath, and abdominal discomfort for four days. He was very ill, pale, and dehydrated. There were enlarged tender submandibular lymph nodes, but no mouth ulcers or other palpable lymph nodes. Peritonitis was excluded by effluent white blood cell count and culture. Empiric antibiotic treatment with ceftriaxon, and ciprofloxacin was started. Gram-negative coccobacilli were isolated by blood culture. The organism was identified as Francisella tularensis. We started him on a ten-day course of gentamicin after which he improved. This is, to the best of our knowledge, the first reported case of bacteremia caused by Francisella tularensis in Sudan.

  3. Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Maria; Bjarnsholt, Thomas; Givskov, Michael

    2014-01-01

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

  4. The importance of timely introduction of vancomycin therapy against methicillin-resistant Staphylococcus aureus (MRSA bacteremia and severity of MRSA bacteremia at Teaching Hospital, Anuradhapura, Sri Lanka

    Directory of Open Access Journals (Sweden)

    Jayaweera Arachchige Asela Sampath Jayaweera

    2017-04-01

    Full Text Available Aim: Worldwide, an estimated 2 billion healthy people carry Staphylococcus aureus (SA and of these, up to 53 million are thought to carry methicillin-resistant SA (MRSA. MRSA bacteremia patients are more critical to manage and timely introduction of antibiotics is life-saving. The aim of the study was to elucidate the prevalence of MRSA bacteremia in different units of Teaching Hospital, Anuradhapura (THA, Sri Lanka and assess the clinical characteristics and associated mortality related to timely introduction of vancomycin therapy. Materials and Methods: The data on MRSA bacteremia which were obtained from THA, for the period of March 2012 to December 2013 were statically analyzed emphasizing the unit-wise prevalence, severity, and comorbidity and timely introduction of vancomycin therapy. Results: The laboratory records of total 13,260 blood cultures were analyzed. Of those, MRSA bacteremia was detected in 61 cultures (9.3%. The highest prevalence of MRSA bacteremia was observed in the nephrology unit. The survival rate of the patients when the vancomycin therapy started before 24 h of receiving the blood culture report was 94.9% and in the instances of the treatment started after 24 h of blood culture report, the survival rate decreased down to 50%. High Pitt Bacteraemia score (PBS (p<0.05 and initiation of vancomycin therapy after 24 h following the receipt of blood culture report (p<0.05 independently affected the MRSA bacteremic patient’s 7th day mortality. Having comorbidities have not shown significant impact on 7th day mortality. Conclusion: The start of vancomycin therapy as earlier as possible following arrival of antibacterial susceptibility test reduces the likelihood of mortality.

  5. Modeling carbon dioxide effect in a controlled atmosphere and its interactions with temperature and pH on the growth of L. monocytogenes and P. fluorescens.

    Science.gov (United States)

    Couvert, Olivier; Guégan, Stéphanie; Hézard, Bernard; Huchet, Véronique; Lintz, Adrienne; Thuault, Dominique; Stahl, Valérie

    2017-12-01

    The effect of carbon dioxide, temperature, and pH on growth of Listeria monocytogenes and Pseudomonas fluorescens was studied, following a protocol to monitor microbial growth under a constant gas composition. In this way, the CO2 dissolution didn't modify the partial pressures in the gas phase. Growth curves were acquired at different temperatures (8, 12, 22 and 37 °C), pH (5.5 and 7) and CO2 concentration in the gas phase (0, 20, 40, 60, 80, 100% of the atmospheric pressure, and over 1 bar). These three factors greatly influenced the growth rate of L. monocytogenes and P. fluorescens, and significant interactions have been observed between the carbon dioxide and the temperature effects. Results showed no significant effect of the CO2 concentration at 37 °C, which may be attributed to low CO2 solubility at high temperature. An inhibitory effect of CO2 appeared at lower temperatures (8 and 12 °C). Regardless of the temperature, the gaseous CO2 is sparingly soluble at acid pH. However, the CO2 inhibition was not significantly different between pH 5.5 and pH 7. Considering the pKa of the carbonic acid, these results showed the dissolved carbon under HCO3- form didn't affect the bacterial inhibition. Finally, a global model was proposed to estimate the growth rate vs. CO2 concentration in the aqueous phase. This dissolved concentration is calculated according to the physical equations related to the CO2 equilibriums, involving temperature and pH interactions. This developed model is a new tool available to manage the food safety of MAP. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Enhanced inactivation of Salmonella and Pseudomonas biofilms on stainless steel by use of T-128, a fresh-produce washing aid, in chlorinated wash solutions.

    Science.gov (United States)

    Shen, Cangliang; Luo, Yaguang; Nou, Xiangwu; Bauchan, Gary; Zhou, Bin; Wang, Qin; Millner, Patricia

    2012-10-01

    The effect of the washing aid T-128 (generally recognized as safe [GRAS] formulation, composed mainly of phosphoric acid and propylene glycol) on inactivation of Salmonella and Pseudomonas populations in biofilms on stainless steel was evaluated under conditions of increasing organic matter loads in chlorinated wash solutions dominated by hypochlorous acid. Biofilms were formed statically on stainless steel coupons suspended in 2% lettuce extract after inoculation with Salmonella enterica serovar Thompson or Newport or with Pseudomonas fluorescens. Coupons with biofilms were washed in chlorine solutions (0, 0.5, 1, 2, 5, 10, or 20 mg/liter at pH 6.5, 5.0 and 2.9), with or without T-128, and with increasing loads of organic matter (0, 0.25, 0.5, 0.75, or 1.0% lettuce extract). Cell populations on coupons were dispersed using intermittent, pulsed ultrasonication and vortexing and enumerated by colony counts on XLT-4 or Pseudomonas agars. Cell responses to fluorescent viability staining of biofilm treatment washing solutions were examined using confocal laser scanning microscopy. Results showed that 0.1% T-128 (without chlorine) reduced P. fluorescens biofilm populations by 2.5 log(10) units but did not reduce Salmonella populations. For both Salmonella and Pseudomonas, the sanitizing effect of free chlorine (1.0 to 5.0 mg/liter) was enhanced (P biofilms compared to treatments without T-128. Image analysis of surfaces stained with SYTO and propidium iodide corroborate the cultural assay results showing that T-128 can aid in reducing pathogen viability in biofilms and thus can aid in sanitizing stainless steel contact surfaces during processing of fresh-cut produce.

  7. Clinical and microbiological characteristics of bacteremia caused by Streptococcus viridans in children with hematologic malignancies

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    M. V. Panina

    2014-01-01

    Full Text Available Bacteremia caused by Streptococcus viridans may be fulminant in neutropenic patients. The clinical signs of streptococcal bacteremiain neutropenic patients are obvious, but non-specific, and are characterized by fever, pulmonary symptoms (pneumonia, respiratory distress syndrome in 20–25 % of cases, hemodynamic instability (about 30 % of cases, rash and followed desquamation, in rare cases – neurological disorders (encephalopathy. Perhaps the main difference from other bacteremia in immunocompromised patients is approximately 10 times higher risk of rapid (during the first two days development of acute lung injury with hypoxemia often requiring oxygen subsidies and respiratory support. Frequency, clinical characteristics and outcomes of streptococcal bacteremia, as well as the spectrum of antibiotics sensitivity was retrospective analyzed in this study. From 2003 to 2009 in children with various oncological and hematological diseases and febrile neutropenia 265 microorganisms were isolated from blood cultures, including Gram-positive in 113 (42 % patients. Strains of Streptococcus viridans, isolated at least once from blood (central venous catheter and / or peripheral veins, are included in analysis. Streptococcus viridans were isolated from the blood of 20 patients, accounting for 7.5 % of the total number of bacteremia and 17.7 % of gram-ositive bacteremia. Patients with acute myeloid leukemia (AML accounted for 45 % of all patients with streptococcal bacteremia, but the incidence of streptococcal bacteremia in AML patients was 8.7 % and did not differ from patients with other diagnoses. 11 (55 % from 20 patients have mucositis at diagnosis of bacteremia, in 14 patients (70 % prior chemotherapy included high dose of cytosine arabinoside. All patients with streptococcal bacteremia have severe neutropenia (median 70 cells / mkl and characterized by fever (100 %, septic shock (8 patients, 40 % and RDS (7 patients, 35 % required high

  8. Predicting bacteremia based on nurse-assessed food consumption at the time of blood culture.

    Science.gov (United States)

    Komatsu, Takayuki; Onda, Toshihito; Murayama, Go; Yamanouchi, Masashi; Inukai, Minori; Sakai, Ai; Kikuta, Masumi; Branch, Joel; Aoki, Makoto; Tierney, Lawrence M; Inoue, Kenji

    2012-01-01

    Bacteremia and its complications are important causes of morbidity and mortality in hospitalized patients. However, the yield of blood cultures is relatively low, with many false-positive results from bacterial contamination. We investigated the relationship between patient food consumption and the presence of bacteremia. This was an observational analysis of a cohort of 1179 patients who underwent blood culture analysis between January 2005 and December 2009. Patients with anorexia-inducing conditions, such as gastrointestinal illness and malignant disease treated with chemotherapy, were excluded. Food consumption was rated by nurses as the percentage of food consumed during the meal preceding the blood culture. Groupings were as follows: low consumption (50% to 80%). Low consumption was observed in 39.8% of patients, moderate in 17.8%, and high in 41.6%. The average body temperature was 38.1 ± 1.1°C. Bacteremia was present in 18.5%, 3.9%, and 1.4% of patients in the low, moderate, and high food consumption groups, respectively. The negative predictive value was 98.3%, suggesting that bacteremia is very unlikely in the setting of good food intake. Bacteremia is an unlikely occurrence in hospitalized patients who maintain adequate food consumption at the time of blood culture. Copyright © 2012 Society of Hospital Medicine.

  9. Comparative genomics of plant-associated Pseudomonas spp.: insights into diversity and inheritance of traits involved in multitrophic interactions.

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    Joyce E Loper

    2012-07-01

    Full Text Available We provide here a comparative genome analysis of ten strains within the Pseudomonas fluorescens group including seven new genomic sequences. These strains exhibit a diverse spectrum of traits involved in biological control and other multitrophic interactions with plants, microbes, and insects. Multilocus sequence analysis placed the strains in three sub-clades, which was reinforced by high levels of synteny, size of core genomes, and relatedness of orthologous genes between strains within a sub-clade. The heterogeneity of the P. fluorescens group was reflected in the large size of its pan-genome, which makes up approximately 54% of the pan-genome of the genus as a whole, and a core genome representing only 45-52% of the genome of any individual strain. We discovered genes for traits that were not known previously in the strains, including genes for the biosynthesis of the siderophores achromobactin and pseudomonine and the antibiotic 2-hexyl-5-propyl-alkylresorcinol; novel bacteriocins; type II, III, and VI secretion systems; and insect toxins. Certain gene clusters, such as those for two type III secretion systems, are present only in specific sub-clades, suggesting vertical inheritance. Almost all of the genes associated with multitrophic interactions map to genomic regions present in only a subset of the strains or unique to a specific strain. To explore the evolutionary origin of these genes, we mapped their distributions relative to the locations of mobile genetic elements and repetitive extragenic palindromic (REP elements in each genome. The mobile genetic elements and many strain-specific genes fall into regions devoid of REP elements (i.e., REP deserts and regions displaying atypical tri-nucleotide composition, possibly indicating relatively recent acquisition of these loci. Collectively, the results of this study highlight the enormous heterogeneity of the P. fluorescens group and the importance of the variable genome in tailoring

  10. Population-based study of the epidemiology and the risk factors for Pseudomonas aeruginosa bloodstream infection.

    Science.gov (United States)

    Parkins, M D; Gregson, D B; Pitout, J D D; Ross, T; Laupland, K B

    2010-02-01

    Detailed population-based data on the epidemiology of Pseudomonas aeruginosa bloodstream infections are sparse. We sought to describe the incidence rate, risk factors, and outcomes associated with P. aeruginosa bacteremia in a large Canadian health region. A retrospective population-based surveillance for P. aeruginosa bacteremia was conducted in the Calgary Health Region (CHR, population:approx. 1.2 million) during the period from 2000 to 2006. A total of 284 incident cases of P. aeruginosa bacteremia were identified in CHR residents, corresponding to an annual incidence rate of 3.6/100,000.Nosocomial acquisition accounted for 45% of cases,healthcare-associated community onset for 34% of cases,and community-acquired (CA) cases for 21%. Relative to the general population, risk factors for blood stream infection included male sex, increasing age, hemodialysis,solid organ transplant, diagnosis of cancer, heart disease, HIV infection, diabetes mellitus, and/or chronic obstructive airway disease (COPD). Overall mortality was 29%. Factors associated with mortality in univariate analysis included pulmonary focus of infection and co-morbidities, including chronic liver disease, substance abuse, heart disease, COPD, and cancer, and increased with the burden of co-morbidities. Despite those patients with CA disease having fewer co-morbidities,they had a significantly higher mortality rate than either healthcare-associated cases or nosocomial cases(RR 1.88, p = 0.05). This study documents that P. aeruginosa bacteremic disease is responsible for a significant burden of illness in general populations and identifies those groups at increased risk of infection and subsequent mortality. This information can be used to identify those individuals likely to benefit from empiric anti-pseudomonal therapies.

  11. Distinguishing Complicated from Uncomplicated Bacteremia Caused by Staphylococcus aureus: The Value of "New" and "Old" Serological Tests

    NARCIS (Netherlands)

    H.A. Verbrugh (Henri); W.H.F. Goessens (Wil); M.F. Michel; R. Peters (Roel)

    1986-01-01

    textabstractAntibody responses to staphylococcal α-toxin, cell wall teichoic acid, and cell wall peptodoglycan were measured in 259 serum samples from 74 consecutive patients with Staphylococcus aureus bacteremia. All patients with complicated bacteremia were seropositive in at least one of three

  12. GENTAMICIN REDUCES BACTEREMIA AND MORTALITY-RATES ASSOCIATED WITH THE TREATMENT OF EXPERIMENTAL PERITONITIS WITH RECOMBINANT TISSUE-PLASMINOGEN ACTIVATOR

    NARCIS (Netherlands)

    van Goor, Harry; de Graaf, JS; KOOI, K; BLEICHRODT, RP

    BACKGROUND: Recombinant tissue plasminogen activator (rtPA), administered intraperitoneally, reduces intra-abdominal abscess formation in rats with fecal peritonitis at the costs of increased mortality and early Escherichia coli bacteremia. It was determined whether or not mortality and bacteremia

  13. [Epidemiology and clinical features of Streptococcus pyogenes bacteremia in Cartagena (Murcia, Spain)].

    Science.gov (United States)

    Jimeno-Almazán, Amaya; Viqueira-Gonzalez, Montserrat; Alcalde, María Del Mar; Alcaraz-Vidal, Begoña; Vera-Méndez, Francisco

    2013-01-01

    A gradual increase in severe cases due to Streptococcus pyogenes or Streptococcus beta-hemolytic group A (SGA), has been detected in the last few decades. Retrospective study of bacteremia due to S.pyogenes detected between January 2009 and January 2013 in Cartagena. The annual incidence for severe bacteremia has been estimated. Thirteen cases of SGA bacteremia were recorded. The incidence increased from 0.37 in 2009 to 2.5 cases/100,000 inhabitants in 2012. The predominant focus was skin and soft tissue infections (53%). Early mortality was 20%. Severe streptococcal disease is rare, but affects individuals with good functional status, and is associated with a high mortality. Copyright © 2012 Elsevier España, S.L. All rights reserved.

  14. Increase in hippocampal water diffusion and volume during experimental pneumococcal meningitis is aggravated by bacteremia

    DEFF Research Database (Denmark)

    Holler, Jon G; Brandt, Christian T; Leib, Stephen L

    2014-01-01

    pneumococci. The study comprised of four experimental groups. I. Uninfected controls (n = 8); II. Meningitis (n = 11); III. Meningitis with early onset bacteremia by additional i.v. injection of live pneumococci (n = 10); IV. Meningitis with attenuated bacteremia by treatment with serotype-specific anti......BACKGROUND: The hippocampus undergoes apoptosis in experimental pneumococcal meningitis leading to neurofunctional deficits in learning and memory function. The aim of the present study was 1) to investigate hippocampal apparent diffusion coefficient (ADC) and volume with MRI during the course...... of experimental pneumococcal meningitis, 2) to explore the influence of accompanying bacteremia on hippocampal water distribution and volume, 3) and to correlate these findings to the extent of apoptosis in the hippocampus. METHODS: Experimental meningitis in rats was induced by intracisternal injection of live...

  15. Nosocomial bacteremia in neonates related to poor standards of care.

    Science.gov (United States)

    Macias, Alejandro E; Munoz, Juan M; Galvan, Amparo; Gonzalez, Juan A; Medina, Humberto; Alpuche, Celia; Cortes, Gabriel; Ponce-de-Leon, Samuel

    2005-08-01

    In developing countries, intravenous liquids are mixed and administered by nurses, sometimes under suboptimal infection control conditions. We hypothesized that outbreaks of infusate-associated neonatal bacteremias are common, and we evaluated whether they can be detected by vigilant microbiologic surveillance of infusates. We studied intravenous infusates administered to neonates in a Mexican hospital where mixtures of infusates were prepared in hospital wards. The study was performed in 3 stages: stage 1, initial culturing of in-use infusates under basal conditions; stage 2, prospective culturing during a cluster of clinical sepsis; and stage 3, final culturing once the outbreak was controlled. In stage 1, 68 infusates were sterile, and 1 was contaminated with Staphylococcus aureus (1.45%), from 23 patients. In stage 2, of 182 infusates from 39 patients, 51 infusates (28%) were contaminated with Gram-negative rods. On the first day of stage 2, 11 of 15 infusates were contaminated with the same strain of Klebsiella pneumoniae, which continued to appear for 26 days. Another 4 strains of Gram-negative rods were also isolated during stage 2. The association between contaminated infusate and death was significant (odds ratio, 9.4; 95% confidence interval, 2-44.3; P < 0.001). Mixtures made by nurses were more likely contaminated than commercial preparations (odds ratio, 3.1; 95% confidence interval, 1.1-8.5; P = 0.037). In stage 3, there were 42 sterile infusates from 22 patients. Our study suggests that poor standards of care common in hospitals from developing countries sometimes result in outbreaks of sepsis and death for newborn patients.

  16. Postoperative bacteremia in periodontal flap surgery, with and without prophylactic antibiotic administration: A comparative study

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    Asi Kanwarjit

    2010-01-01

    Full Text Available Objectives: Many a times in clinical periodontology, the decision whether to prescribe prophylactic antibiotics or not , is perplexing.The present study was conducted to compare the bacteremias induced after periodontal flap surgeries with and without prophylactic antibiotics. Materials and Methods: The occurrence of postoperative bacteremia following periodontal flap surgery was studied in 30 patients. On these patients, 30 quadrant wise flap surgeries were carried out without any preoperative prophylactic antibiotics and 30 surgeries carried out after prophylactic administration of amoxycillin preoperatively. A blood sample was taken from each patient at the time of maximum surgical trauma and was cultured for micro-organisms and antibiotic sensitivity. Results: 18 out of 60 blood samples were positive for micro-organisms. There was a significant reduction in post operative bacteremia after amoxycillin prophylaxis (x - 7.96 with P< 0.01 as post operative bacteremia was found in 14 of the non medicated patients as compared to only 4 of the pre medicated patients. The micro-organisms encountered in the study are as follows:- 1 Staphylococcus albus coagulase negative, 2 Klebsiella, 3 Psedomonas aerugenosa, 4 Streptococcus viridans, 5 Alpha hemolytic streptococcus, 6 Neisseria catarrhalis Conclusion: On the basis of the study, it is concluded that the incidence of postoperative bacteremia following periodontal flap surgery is not as high as previously reported. The clinical results show that Amoxicillin is highly effective in reducing postoperative bacteremia in periodontal flap surgery and thus in preventing the possible sequelae (Infective Endocarditis and other systemic maladies in susceptible patients. However, cefotaxime and cephalexin may prove to be more effective in preventing the same.

  17. Clinical Pharmacist Management of Bacteremia in a Community Hospital Emergency Department.

    Science.gov (United States)

    Waters, C Dustin; Bitton, Bryce J; Torosyan, Annie; Myers, Kevin P

    2017-06-01

    Bacteremia is a serious condition that leads to high morbidity and mortality. Data describing pharmacist involvement in the management of bacteremia in the emergency department are lacking. To determine if pharmacist involvement in the management of bacteremia in the emergency department (ED) led to an increase in appropriate treatment of bacteremia as well as improvements in patient outcomes. The primary outcome of this retrospective cohort study was the rate of appropriate treatment of bacteremia. Secondary outcomes included the rate of unplanned, infectious disease-related 90-day admission or readmission to the ED or hospital as well as infectious disease-related 90-day mortality. All patients seen in the ED and subsequently discharged who had a positive blood culture determined not to be a contaminant were included in the study. Patients were analyzed in 2 cohorts: those that were physician managed (107 patients) and those that were pharmacist managed (138 patients). In the physician-managed cohort, 50 of 107 (47%) patients were treated appropriately compared with 131 of 138 (95%) patients in the pharmacist-managed cohort ( P managed patients, which occurred in 4 of 138 patients (2.9%) versus the physician-managed patient cohort in which 13 of 107 patients (12.1%) were readmitted ( P = 0.01). There was no difference in mortality between the groups ( P = 0.8337). Pharmacist involvement in the management of bacteremia in the ED was associated with higher rates of appropriate treatment and a corresponding decrease in the rates of attributable 90-day admission or readmission to the hospital or ED.

  18. Clinical features of children with nontyphoidal Salmonella bacteremia: A single institution survey in rural Japan.

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    Yoshihiro Aoki

    Full Text Available Nontyphoidal Salmonella (NTS can cause bacterial enterocolitis. Although some children with NTS infection develop bacteremia, its clinical manifestations have not been discussed adequately. Therefore, we examined children with NTS bacteremia. We retrospectively examined the medical records of 15 patients aged less than 15 years. Salmonella spp. were detected in the blood cultures of these patients between 1991 and 2014. We divided an additional sample group of 34 patients diagnosed with an NTS infection between 2005 and 2014, into 2 groups. Group bacteremia (B included patients in whose blood cultures Salmonella spp. were detected, and group non-bacteremia (NB included patients in whom Salmonella infection was not detected. We compared each group using Wilcoxon test and Fisher's exact test. The number of patients with fever, diarrhea, or abdominal pain was 15 (100%, 13 (87%, and 9 (60%, respectively, in the first sample of patients. However, vomiting and bloody stool were observed in only 5 patients (33%. More than 70% of patients exhibited a reduced white blood cell count, while C-reactive protein levels were variable in the patients. Salmonella spp. were detected via stool culture in 10 patients (67%. Diarrhea persisted for more than 4 days more frequently in group B than group NB (p = 0.004. The number of patients whose fever persisted for more than 4 days was significantly higher in group B than group NB (p = 0.030. Therefore, if NTS bacteremia is suspected, blood cultures should be collected and antibiotics should be initiated in cases with diarrhea or fever for more than 4 days. Furthermore, a negative stool culture result does not preclude the possibility of NTS bacteremia.

  19. Bacteremia caused by antimicrobial resistant Campylobacter species at a medical center in Taiwan, 1998-2008.

    Science.gov (United States)

    Liao, Chun-Hsing; Chuang, Chia-Yunn; Huang, Yu-Tsung; Lee, Ping-Ing; Hsueh, Po-Ren

    2012-11-01

    This study was intended to delineate the clinical and microbiological characteristics of patients with bacteremia caused by Campylobacter species. Twenty-four patients with Campylobacter bacteremia were treated at the National Taiwan University Hospital from 1998 to 2008. All isolates from the 24 patients were confirmed to the species level by multiplex PCR (cadF, hipO and asp gene) and 16S RNA gene sequencing. Bacteremia was caused by Campylobacter coli in 15 (62.5%) patients, Campylobacter fetus in 6 (25%), and Campylobacter jejuni in 3 (12.5%). Of the 24 patients, 16 were male. The major underlying conditions included chronic renal insufficiency (41.7%), liver cirrhosis (37.5%), malignancy (33.3%), and previous abdominal surgery (33.3%). The most common infections were intra-abdominal infection (54.2%), followed by primary bacteremia (41.7%), and cellulitis (4.2%). The mean Pittsburgh bacteremia score was 2.5 (range, 0-9). During the bacteremic episodes, six (25%) patients developed septic shock. Third-generation cephalosporins were administered to 12 (50%) patients as empirical therapy. All-cause mortality was 4.2% at 14 days and 12.5% at 30 days. The majority of the isolates were resistant to third-generation cephalosporins and quinolones, with minimum inhibitory concentration (MIC(90)) values of 32 mg/L for cefotaxime, 128 mg/L for ceftriaxone, and 32 mg/L for both ciprofloxacin and levofloxacin. All isolates possessed a parC mutation (Arg-139-Gln) and 15 exhibited an additional gyrA mutation (Thr-86-Ile). Among these isolates, 20.8% were susceptible to erythromycin (MIC≤0.5 mg/L). Bacteremia caused by antimicrobial resistant Campylobacter species is alarming although the mortality rate is low. Copyright © 2012 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  20. Clinical manifestations of bacteremia caused by Aeromonas species in southern Taiwan.

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    Hung-Jen Tang

    Full Text Available This study is conducted to investigate the clinical characteristics of patients with bacteremia caused by Aeromonas species.Patients with bacteremia caused by Aeromonas species during the period 2009 to 2013 were identified from a computerized database of a regional hospital in southern Taiwan. The medical records of these patients were retrospectively reviewed.A total of 91 patients with bacteremia due to Aeromonas species were identified. In addition to 16 (17.6% primary bacteremia, the most common source of secondary infection is peritonitis (n = 27, 29.7%, followed by biliary tract infection (n = 18, 19.8%, and SSTI (n = 12, 13.2%, pneumonia (n = 9, 9.9%, catheter-related bloodstream infection (n =  5, 5.5%, and genitourinary tract infection (n = 4, 4.4%. A. hydrophila (n = 35, 38.5% was the most common pathogen, followed by A. veronii biovar sobria (n = 31, 34.1%, A. caviae (n = 14, 15.4%, and A. veronii biovar veronii (n = 9, 9.9%. Forty-three (47.3% patients were classified as healthcare-associated infections (HCAI causes by Aeromonas species, and patients with HCAI were more likely to have cancer, and receive immunosuppressant than patients with community-acquired bacteremia. The overall outcomes, including rate of ICU admission, acute respiratory failure, and mortality were 33.3%, 28.6%, and 23.1%, respectively. Multivariate analysis showed that the in-hospital day mortality was significantly associated only with underlying cancer (P <.001, and initial shock (P <.001.Aeromonas species should be considered one of the causative pathogens of healthcare-associated bacteremia, especially in immunocompromised patients. In addition, it can be associated with high fatality. Cancer and initial shock were the poor prognostic factors.

  1. [Meningoencephalitis caused by Pseudomonas cepacia].

    Science.gov (United States)

    Pérez Monrás, Miriam Fina; Batlle Almodóvar, María del Carmen; González, Cernero; Tamargo Martínez, Isis; Meneses, Félix Dickinson

    2006-01-01

    A case of meningoencephalitis of bacterial etiology caused by Pseudomonas cepacia was described. The strain was received at the Reference Laboratory of Bacterial Acute Respiratory Infections of "Pedro Kouri" Institute of Tropical Medicine, where its microbiological identification was confirmed. This isolation was a finding in an adult immunocompetent patient. The evolution was favourable with no sequelae for his future life. Pseudomona cepacia has been associated with respiratory infections in patients with cystic fibrosis. Patients with Pseudomonas cepacia may be asymptomatic or present fatal acute and fulminant infection.

  2. 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...

  3. Successful treatment of refractory listeria meningitis and bacteremia with trimethoprim-sulfamethoxazole in an immunocompetent child.

    Science.gov (United States)

    Polat, Meltem; Kara, Soner Sertan; Tapısız, Anıl; Derinöz, Okşan; Çağlar, Kayhan; Tezer, Hasan

    2016-01-01

    Listeria monocytogenes is an important cause of life-threatening bacteremia and meningoencephalitis in neonates, pregnant women, the elderly, and immunocompromised individuals. However, it is an uncommon cause of illness in immunocompetent children beyond the neonatal period. Ampicillin with or without an aminoglycoside remains the best treatment for listeriosis. Here, we report a rare case of Listeria meningitis and bacteremia in a 7-month-old immunocompetent girl, which was refractory to ampicillin plus gentamicin treatment and successfully treated by the addition of TMP/SMX.

  4. Successful Treatment of Bacillus cereus Bacteremia in a Patient with Propionic Acidemia

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    Fatma Deniz Aygun

    2016-01-01

    Full Text Available Bacillus cereus can cause serious, life-threatening, systemic infections in immunocompromised patients. The ability of microorganism to form biofilm on biomedical devices can be responsible for catheter-related bloodstream infections. Other manifestations of severe disease are meningitis, endocarditis, osteomyelitis, and surgical and traumatic wound infections. The most common feature in true bacteremia caused by Bacillus is the presence of an intravascular catheter. Herein, we report a case of catheter-related bacteremia caused by B. cereus in a patient with propionic acidemia.

  5. Successful Treatment of Bacillus cereus Bacteremia in a Patient with Propionic Acidemia.

    Science.gov (United States)

    Aygun, Fatma Deniz; Aygun, Fatih; Cam, Halit

    2016-01-01

    Bacillus cereus can cause serious, life-threatening, systemic infections in immunocompromised patients. The ability of microorganism to form biofilm on biomedical devices can be responsible for catheter-related bloodstream infections. Other manifestations of severe disease are meningitis, endocarditis, osteomyelitis, and surgical and traumatic wound infections. The most common feature in true bacteremia caused by Bacillus is the presence of an intravascular catheter. Herein, we report a case of catheter-related bacteremia caused by B. cereus in a patient with propionic acidemia.

  6. The effect of S. pneumoniae bacteremia on cerebral blood flow autoregulation in rats

    DEFF Research Database (Denmark)

    Pedersen, Michael; Brandt, Christian T.; Knudsen, Gitte Moos

    2008-01-01

    In the present study, we studied the effect of bacteremia on cerebral blood flow (CBF) autoregulation in a rat model of pneumococcal bacteremia and meningitis. Anesthetized rats were divided into five groups (A to E) and inoculated with pneumococci intravenously and normal saline intracisternally......); or saline intravenously and saline intracisternally (group E, N=10), respectively. Positive cultures occurred in the blood for all rats in groups A, B, and C, and in the cerebrospinal fluid for all rats in groups D and E. Twenty-four hours after inoculation, CBF was measured with laser-Doppler ultrasound...

  7. A case of disseminated intravascular coagulation secondary to Acinetobacter lwoffii and Acinetobacter baumannii bacteremia

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    Candice Baldeo

    2015-01-01

    Full Text Available Bacteremia is currently one of the infections with the highest mortality in hospitals [1]. Acinetobacter lwoffii and Acinetobacter baumannii are gram-negative bacteria and both represent opportunistic pathogens. In certain cases, the management can be challenging since these organisms can be highly resistant to antimicrobial agents. Clinical illnesses associated with Acinetobacter include pneumonia, meningitis, peritonitis, endocarditis and infections of the urinary tract and skin [1]. Acinetobacter bacteremia represents a serious and ever increasing problem because of the high associated morbidity and mortality.

  8. Can Levofloxacin Be a Useful Alternative to Trimethoprim-Sulfamethoxazole for Treating Stenotrophomonas maltophilia Bacteremia?

    Science.gov (United States)

    Cho, Sun Young; Kim, Jungok; Ha, Young Eun; Chung, Doo Ryeon; Lee, Nam Yong; Peck, Kyong Ran; Song, Jae-Hoon

    2014-01-01

    A retrospective study was conducted to evaluate the efficacy of levofloxacin in the treatment of Stenotrophomonas maltophilia bacteremia. The 30-day mortality rates were similar between the trimerthoprim-sulfamethoxazole (TMP-SMX) and levofloxacin treatment groups. Adverse events related to antibiotics occurred more frequently in patients receiving TMP-SMX, and recurrent bacteremia due to levofloxacin-resistant S. maltophilia strains developed in patients treated with levofloxacin. Our data suggest that levofloxacin can be a useful alternative option for treating S. maltophilia infections. PMID:24126583

  9. Brevundimonas vesicularis bacteremia: A rare case report in a female infant

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    S M Bhatawadekar

    2011-01-01

    Full Text Available Brevundimonas vesicularis has rarely been isolated from clinical specimens. We report here a case of B. vesicularis bacteremia in a female infant who presented with fever, vomiting and altered sensorium. USG abdomen showed mild hepatomegaly, moderate ascitis with bilateral mild basal pleural effusion. Blood culture was processed by BACTEC BD. Isolate was identified as B. vesicularis, by API ID 32 GN automated system. We have come across only one report of neonatal sepsis caused by B. vesicularis from India. To the best of our knowledge, this is one of the rare case reports of B. vesicularis bacteremia in a female infant.

  10. Comparative genome analysis of the vineyard weed endophyte Pseudomonas viridiflava CDRTc14 showing selective herbicidal activity.

    Science.gov (United States)

    Samad, Abdul; Antonielli, Livio; Sessitsch, Angela; Compant, Stéphane; Trognitz, Friederike

    2017-12-11

    Microbes produce a variety of secondary metabolites to be explored for herbicidal activities. We investigated an endophyte Pseudomonas viridiflava CDRTc14, which impacted growth of its host Lepidium draba L., to better understand the possible genetic determinants for herbicidal and host-interaction traits. Inoculation tests with a variety of target plants revealed that CDRTc14 shows plant-specific effects ranging from beneficial to negative. Its herbicidal effect appeared to be dose-dependent and resembled phenotypically the germination arrest factor of Pseudomonas fluorescens WH6. CDRTc14 shares 183 genes with the herbicidal strain WH6 but the formylaminooxyvinylglycine (FVG) biosynthetic genes responsible for germination arrest of WH6 was not detected. CDRTc14 showed phosphate solubilizing ability, indole acetic acid and siderophores production in vitro and harbors genes for these functions. Moreover, genes for quorum sensing, hydrogen cyanide and ACC deaminase production were also found in this strain. Although, CDRTc14 is related to plant pathogens, we neither found a complete pathogenicity island in the genome, nor pathogenicity symptoms on susceptible plant species upon CDRTc14 inoculation. Comparison with other related genomes showed several unique genes involved in abiotic stress tolerance in CDRTc14 like genes responsible for heavy metal and herbicide resistance indicating recent adaptation to plant protection measures applied in vineyards.

  11. Escherichia coli BdcA controls biofilm dispersal in Pseudomonas aeruginosa and Rhizobium meliloti

    Directory of Open Access Journals (Sweden)

    Wood Thomas K

    2011-10-01

    Full Text Available Abstract Background Previously we showed that BdcA controls Escherichia coli biofilm dispersal by binding the ubiquitous bacterial signal cyclic diguanylate (c-di-GMP; upon reducing the concentration of c-di-GMP, the cell shifts to the planktonic state by increasing motility, decreasing aggregation, and decreasing production of biofilm adhesins. Findings Here we report that BdcA also increases biofilm dispersal in other Gram-negative bacteria including Pseudomonas aeruginosa, Pseudomonas fluorescens, and Rhizobium meliloti. BdcA binds c-di-GMP in these strains and thereby reduces the effective c-di-GMP concentrations as demonstrated by increases in swimming motility and swarming motility as well as by a reduction in extracellular polysaccharide production. We also develop a method to displace existing biofilms by adding BdcA via conjugation from E. coli in mixed-species biofilms. Conclusion Since BdcA shows the ability to control biofilm dispersal in diverse bacteria, BdcA has the potential to be used as a tool to disperse biofilms for engineering and medical applications.

  12. Comparison of outcome and clinical characteristics of bacteremia caused by methicillin-resistant, penicillin-resistant and penicillin-susceptible Staphylococcus aureus strains.

    Science.gov (United States)

    Jokinen, Elina; Laine, Janne; Huttunen, Reetta; Rahikka, Pekka; Huhtala, Heini; Vuento, Risto; Vuopio, Jaana; Syrjänen, Jaana

    2017-07-01

    The aim of this study was to assess the association of methicillin resistance and penicillinase production with clinical characteristics and outcome of Staphylococcus aureus bacteremia. For 126 patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, 378 age- and gender-matched controls with methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia were selected. Of controls, 126 had bacteremia caused by penicillin-susceptible strains (PSSA) and 252 by penicillinase-producing strains (PRSA). Underlying diseases, clinical course and mortality were retrospectively assessed. Patients with MRSA bacteremia were more often smokers than patients with MSSA bacteremia (OR 2.34, 95% CI 1.27-4.32). MRSA bacteremia was more often healthcare-associated (OR 4.23, 95% CI 2.47-7.24), associated with central venous catheters (OR 2.09, 95% CI 1.27-3.47), glucocorticoid therapy (OR 1.82, 95% CI 1.12-2.93) and prior surgery (OR 2.32, 95% CI 1.43-3.76). Patients with MRSA bacteremia received appropriate empiric antibiotic (31%) less often than controls (98%). Mortality within 28 days was higher in MRSA bacteremia (26.8%) than in MSSA bacteremia (15.5%) (OR 2.00, 95% CI 1.20-3.34), PRSA bacteremia (17.0%) (OR 1.79 95% CI 1.04-3.09) or PSSA bacteremia (12.5%) (OR 2.56 95% CI 1.27-5.15). The difference remained after adjusting for underlying diseases and foci. There was no significant difference in clinical course between PRSA and PSSA bacteremias. MRSA bacteremia was associated with poorer outcome than either PRSA or PSSA bacteremia. We corroborated several risk factors found in previous studies.

  13. Pseudomonas folliculitis in Arabian baths.

    Science.gov (United States)

    Molina-Leyva, Alejandro; Ruiz-Ruigomez, Maria

    2013-07-14

    A 35-year-old man presented with a painful cutaneous skin eruption that was localized on the upper trunk. He stated that the previous weekend he had attended an Arabian bath. The physical examination revealed multiple hair follicle-centered papulopustules surrounded by an erythematous halo. A clinical diagnosis of pseudomonas folliculitis was made and treatment was prescribed. Afterwards Pseudomonas aeruginosa was isolated from a pustule culture. Pseudomonas folliculitis is a bacterial infection of the hair follicles. The most common reservoirs include facilities with hot water and complex piping systems that are difficult to clean, such as hot tubs and bathtubs. Despite adequate or high chlorine levels, Pseudomonas aeruginosa can grow within a biofilm.

  14. Final screening assessment for Pseudomonas putida ATCC 12633, Pseudomonas putida ATCC 31483, Pseudomonas putida ATCC 31800, Pseudomonas putida ATCC 700369

    National Research Council Canada - National Science Library

    2017-01-01

    "Pursuant to paragraph 74(b) of the Canadian Environmental Protection Act, 1999 (CEPA), the Minister of the Environment and the Minister of Health have conducted a screening assessment on four strains of Pseudomonas putida...

  15. Chronic Pseudomonas aeruginosa cervical osteomyelitis

    Directory of Open Access Journals (Sweden)

    Sujeet Kumar Meher

    2016-01-01

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

  16. Clinical features, risk factors and outcomes of bacteremia due to enterococci with high-level gentamicin resistance: comparison with bacteremia due to enterococci without high-level gentamicin resistance.

    Science.gov (United States)

    Jang, Hee-Chang; Lee, Shinwon; Song, Kyoung-Ho; Jeon, Jae Hyun; Park, Wan Beom; Park, Sang-Won; Kim, Hong Bin; Kim, Nam Joong; Kim, Eui-Chong; Oh, Myoung-Don; Choe, Kang Won

    2010-01-01

    High-level gentamicin resistance (HLGR) in enterococci has increased since the 1980s, but the clinical significance of the resistance and its impact on outcome have not been established. One hundred and thirty-six patients with bacteremia caused by enterococci with HLGR (HLGR group) were compared with 79 patients with bacteremia caused by enterococci without HLGR (non-HLGR group). Hematologic malignancy, neutropenia, Enterococcus faecium infection, nosocomial infection and monomicrobial bacteremia were more common in the HLGR group than the non-HLGR group, and APACHE II scores were also higher (P<0.05, in each case). Neutropenia, monomicrobial infection, stay in intensive care at culture, and use of 3rd generation cephalosporin, were independent risk factors for acquisition of HLGR enterococcal bacteremia. Fourteen-day and 30-day mortalities were higher in the HLGR group than the non-HLGR group in univariate analysis (37% vs. 15%, P=0.001; 50% vs. 22%, P<0.001). However, HLGR was not an independent risk factor for mortality due to enterococcal bacteremia in multivariate analysis. Therefore, HLGR enterococcal bacteremia is associated with more severe comorbid conditions and higher mortality than non-HLGR enterococcal bacteremia but the HLGR itself does not contribute significantly to mortality.

  17. Comparative evaluation of organic formulations of Pseudomonas ...

    African Journals Online (AJOL)

    CVPf formulation and seed + root + soil method of application performed significantly better than others with 83.33% control of bacterial wilt of brinjal in field experiment conducted by completely randomized block design. Effective management of bacterial wilt of brinjal by P. fluorescens under local conditions signifies its ...

  18. An analysis of Pseudomonas genomic diversity in take-all infected wheat fields reveals the lasting impact of wheat cultivars on the soil microbiota.

    Science.gov (United States)

    Mauchline, T H; Chedom-Fotso, D; Chandra, G; Samuels, T; Greenaway, N; Backhaus, A; McMillan, V; Canning, G; Powers, S J; Hammond-Kosack, K E; Hirsch, P R; Clark, I M; Mehrabi, Z; Roworth, J; Burnell, J; Malone, J G

    2015-11-01

    Manipulation of the soil microbiota associated with crop plants has huge promise for the control of crop pathogens. However, to fully realize this potential we need a better understanding of the relationship between the soil environment and the genes and phenotypes that enable microbes to colonize plants and contribute to biocontrol. A recent 2 years of investigation into the effect of wheat variety on second year crop yield in the context of take-all fungal infection presented the opportunity to examine soil microbiomes under closely defined field conditions. Amplicon sequencing of second year soil samples showed that Pseudomonas spp. were particularly affected by the wheat cultivar grown in year one. Consequently, 318 rhizosphere-associated Pseudomonas fluorescens strains were isolated and characterized across a variety of genetic and phenotypic traits. Again, the wheat variety grown in the first year of the study was shown to exert considerable selective pressure on both the extent and nature of Pseudomonas genomic diversity. Furthermore, multiple significant correlations were identified within the phenotypic/genetic structure of the Pseudomonas population, and between individual genotypes and the external wheat field environment. The approach outlined here has considerable future potential for our understanding of plant-microbe interactions, and for the broader analysis of complex microbial communities. © 2015 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  19. Magnitude of enterococcal bacteremia in trauma patients admitted for intensive trauma care: A tertiary care experience from South Asian country

    Directory of Open Access Journals (Sweden)

    Nonika Rajkumari

    2015-01-01

    Full Text Available Background: Bloodstream infection (BSI and bacteremias due to Enterococcus spp. are increasing worldwide with the current need to understand its causes among hospitalized trauma patients. Hence, the study was conducted. Methodology: A 3-year retrospective laboratory cum clinical based study was performed at a level I trauma center in India. Patients with health care associated enterococcal bacteremia were identified using the hospital database, their episodes of BSI/bacteremia calculated and their clinical records and treatment were noted. Results: A total of 104 nonrepetitive Enterococcus spp. was isolated of which Enterococcus faecium was the most common (52%. High-level resistance to gentamicin high-level aminoglycoside resistance was seen in all the Enterococcus spp. causing bacteremia, whereas a low resistance to vancomycin and teichoplanin was observed. Overall mortality was more in patients infected with vancomycin-resistant Enterococcus (5/11, 46% compared to those with vancomycin sensitive Enterococcus (9/93, 10%; though no significant association of mortality with Enterococcus spp. bacteremia ( P > 0.05 was seen. The rate of bacteremia due to Enterococcus spp. was 25.4 episodes/1,000 admissions (104/4,094 during the study period. Conclusion: Enterococcal bacteremia is much prevalent in trauma care facilities. Here, a microbiologist can act as a sentinel and help in preventing such infections.

  20. Does the empiric use of vancomycin in pediatrics increase the risk for Gram-negative bacteremia?

    NARCIS (Netherlands)

    Cuno, SPMU; Heesen, GJM; Arends, JP; Kimpen, JLL; van Houten, M.A.

    Background, Gram-negative bacteremia in children, a major cause of morbidity and mortality, may in part be induced by intensive treatment procedures and nonspecific use of antibiotics. Our primary objective was to study the causal relationship between the use of vancomycin and Gram-negative