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Sample records for pseudomonas aeruginosa bacteria

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

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    Ace Baehaki1

    2008-06-01

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

  2. 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 ...

  3. A bacteria-specific 2[4Fe-4S] ferredoxin is essential in Pseudomonas aeruginosa

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    Diallinas George

    2010-10-01

    Full Text Available Abstract Background Ferredoxins are small iron-sulfur proteins belonging to all domains of life. A sub-group binds two [4Fe-4S] clusters with unequal and extremely low values of the reduction potentials. These unusual properties are associated with two specific fragments of sequence. The functional importance of the very low potential ferredoxins is unknown. Results A bioinformatic screening of the sequence features defining very low potential 2[4Fe-4S] ferredoxins has revealed the almost exclusive presence of the corresponding fdx gene in the Proteobacteria phylum, without occurrence in Archaea and Eukaryota. The transcript was found to be monocistronic in Pseudomonas aeruginosa, and not part of an operon in most bacteria. Only fdx genes of bacteria which anaerobically degrade aromatic compounds belong to operons. As this pathway is not present in all bacteria having very low potential 2[4Fe-4S] ferredoxins, these proteins cannot exclusively be reductants of benzoyl CoA reductases. Expression of the ferredoxin gene did not change in response to varying growth conditions, including upon macrophage infection or aerobic growth with 4-hydroxy benzoate as carbon source. However, it increased along the growth curve in Pseudomonas aeruginosa and in Escherichia coli. The sequence immediately 5' upstream of the coding sequence contributed to the promotor activity. Deleting the fdx gene in Pseudomonas aeruginosa abolished growth, unless a plasmid copy of the gene was provided to the deleted strain. Conclusions The gene of the very low potential 2[4Fe-4S] ferredoxin displays characteristics of a housekeeping gene, and it belongs to the minority of genes that are essential in Pseudomonas aeruginosa. These data identify a new potential antimicrobial target in this and other pathogenic Proteobacteria.

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

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    Ke-chun Jiang

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

  5. 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...

  6. Silver against Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

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

    2007-01-01

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

  7. Surveillance of bacteria Pseudomonas aeruginosa and MRSA associated with chronic suppurative otitis media

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    Sibanarayan Rath

    Full Text Available Abstract Introduction: Suppurative otitis media is a critical disease causing perforation of the tympanic membrane associated with changes of the mucoperiosteum of the middle ear cleft. Objective: To isolate causative bacteria from chronic suppurative ear discharges and to ascertain their antibiotic profiles, of patients attending outpatients department in 3 years. Methods: For isolation of bacteria, samples of ear discharges were grown in suitable media and bacteria were subjected to antibiotic profiling by the Kirby-Bauer's method with presently used antibiotics. Results: A total of 1043 bacteria were isolated, including Pseudomonas aeruginosa and methicillin resistant Staphylococcus aureus, along with 121 fungal isolates. Among 371 P. aeruginosa isolates, tobramycin 30 had the highest susceptibility rate 93.2%, followed by ceftazidime 30, 91.5% and amikacin 10 µg/disk 64.4%. Of 359 S. aureus isolates, there were 236 coagulase negative S. aureus + methicillin sensitive S. aureus isolates, while 123 isolates were methicillin resistant Staphylococcus aureus with 95.2% isolates susceptible to cloxacillin 15, 83.3% isolates to erythromycin 15 and 78.5% isolates to gentamicin 30 µg/disk. Of 1164, 49 patients presented post aural abscess, 12 patients had intracranial complications, 9 patients had facial palsy and 3 patients had labyrinthitis. More than 90% P. aeruginosa and 90% S. aureus isolates were sensitive to tobramycin 30 and cloxacillin 30 µg/disk, respectively. Conclusion: Multidrug resistant strains of P. aeruginosa were more prevalent than those of S. aureus in ear discharges. Tobramycin and cloxacillin may be included in the formulatory antibiotic regimen to overcome bacterial infections in chronic suppurative otitis media.

  8. 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...

  9. RND efflux pump mediated antibiotic resistance in Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa: a major issue worldwide.

    Science.gov (United States)

    Puzari, Minakshi; Chetia, Pankaj

    2017-02-01

    Therapeutic failures against diseases due to resistant Gram-negative bacteria have become a major threat nowadays as confirmed by surveillance reports across the world. One of the methods of development of multidrug resistance in Escherichia coli and Pseudomonas aeruginosa is by means of RND efflux pumps. Inhibition of these pumps might help to combat the antibiotic resistance problem, for which the structure and regulation of the pumps have to be known. Moreover, judicious antibiotic use is needed to control the situation. This paper focuses on the issue of antibiotic resistance as well as the structure, regulation and inhibition of the efflux pumps present in Escherichia coli and Pseudomonas aeruginosa.

  10. The Survey of Withani somnifera Extraction against Resistant Strains of Pseudomonas aeruginosa Bacteria to Selective Antibiotics

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    Mohammad Bokaeian

    2015-11-01

    Full Text Available Introduction:  Due  to  more  resistance  of  pathogenic  bacteria  to  new  and  current antibiotics  researchers  are  looking  to  find  the  agents  of  herbal  with  antimicrobial activities in order to replace chemical drugs.Methods:   The herbal extract of Withani somnifera was done by using a rotary vacuum,20 strains of Pseudomons aeruginosa were isolated from urinary infections hospitalized patients  in  city of Zabol  hospital.  The  MIC  Withani  somnifera  were  determined  by dilution method in various concentrations. Sensitivity of strains to multiple antibiotics was evaluated by standard disk diffusion Kirby-Bauer.Results:    The  result  showed  that  P.  aeruginosa  were  resistance  to  4  of the  agents including ampicillin  (85%, nitrofurantoin  (65%, nalidixic acid  (65%, ciprofloxacin (15% and for 5 strains of Pseudomonas showed MIC with activity of 100 ppm.Conclusion:   This  study  has  suggested  the  effect  of  winter  cherry  extract  on  P. aeruginosa in the in vitro assay. It s effectiveness of on in vivo system can be examined in future.

  11. Anti-Biofilm Activities from Marine Cold Adapted Bacteria Against Staphylococci and Pseudomonas aeruginosa.

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    Papa, Rosanna; Selan, Laura; Parrilli, Ermenegilda; Tilotta, Marco; Sannino, Filomena; Feller, Georges; Tutino, Maria L; Artini, Marco

    2015-01-01

    Microbial biofilms have great negative impacts on the world's economy and pose serious problems to industry, public health and medicine. The interest in the development of new approaches for the prevention and treatment of bacterial adhesion and biofilm formation has increased. Since, bacterial pathogens living in biofilm induce persistent chronic infections due to the resistance to antibiotics and host immune system. A viable approach should target adhesive properties without affecting bacterial vitality in order to avoid the appearance of resistant mutants. Many bacteria secrete anti-biofilm molecules that function in regulating biofilm architecture or mediating the release of cells from it during the dispersal stage of biofilm life cycle. Cold-adapted marine bacteria represent an untapped reservoir of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules. The anti-biofilm activity of cell-free supernatants derived from sessile and planktonic cultures of cold-adapted bacteria belonging to Pseudoalteromonas, Psychrobacter, and Psychromonas species were tested against Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa strains. Reported results demonstrate that we have selected supernatants, from cold-adapted marine bacteria, containing non-biocidal agents able to destabilize biofilm matrix of all tested pathogens without killing cells. A preliminary physico-chemical characterization of supernatants was also performed, and these analyses highlighted the presence of molecules of different nature that act by inhibiting biofilm formation. Some of them are also able to impair the initial attachment of the bacterial cells to the surface, thus likely containing molecules acting as anti-biofilm surfactant molecules. The described ability of cold-adapted bacteria to produce effective anti-biofilm molecules paves the way to further characterization of the most promising molecules and to test their

  12. Anti-biofilm activities from marine cold adapted bacteria against staphylococci and Pseudomonas aeruginosa

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    Rosanna ePapa

    2015-12-01

    Full Text Available Microbial biofilms have great negative impacts on the world’s economy and pose serious problems to industry, public health and medicine. The interest in the development of new approaches for the prevention and treatment of bacterial adhesion and biofilm formation has increased. Since, bacterial pathogens living in biofilm induce persistent chronic infections due to the resistance to antibiotics and host immune system. A viable approach should target adhesive properties without affecting bacterial vitality in order to avoid the appearance of resistant mutants. Many bacteria secrete anti-biofilm molecules that function in regulating biofilm architecture or mediating the release of cells from it during the dispersal stage of biofilm life cycle. Cold-adapted marine bacteria represent an untapped reservoir of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules.The anti-biofilm activity of cell-free supernatants derived from sessile and planktonic cultures of cold-adapted bacteria belonging to Pseudoalteromonas, Psychrobacter and Psychromonas species were tested against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa strains. Reported results demonstrate that we have selected supernatants, from cold-adapted marine bacteria, containing non-biocidal agents able to destabilize biofilm matrix of all tested pathogens without killing cells. A preliminary physico-chemical characterization of supernatants was also performed, and these analyses highlighted the presence of molecules of different nature that act by inhibiting biofilm formation. Some of them are also able to impair the initial attachment of the bacterial cells to the surface, thus likely containing molecules acting as anti-biofilm surfactant molecules.The described ability of cold-adapted bacteria to produce effective anti-biofilm molecules paves the way to further characterization of the most promising molecules

  13. Inhibition of quorum sensing in Pseudomonas aeruginosa biofilm bacteria by a halogenated furanone compound

    DEFF Research Database (Denmark)

    Hentzer, Morten; Riedel, Kathrin; Rasmussen, Thomas B

    2002-01-01

    Novel molecular tools have been constructed which allow for in situ detection of N-acyl homoserine lactone (AHL)-mediated quorum sensing in Pseudomonas aeruginosa biofilms. The reporter responds to AHL activation of LasR by expression of an unstable version of the green-fluorescent protein (Gfp)....

  14. Identification and discrimination of Pseudomonas aeruginosa bacteria grown in blood and bile by laser-induced breakdown spectroscopy

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    Rehse, Steven J. [Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201 (United States)], E-mail: rehse@wayne.edu; Diedrich, Jonathan [Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201 (United States)], E-mail: jon.diedrich@gd-ais.com; Palchaudhuri, Sunil [Department of Immunology and Microbiology, Wayne State University, Detroit, MI 48201 (United States)], E-mail: spalchau@med.wayne.edu

    2007-10-15

    Pseudomonas aeruginosa bacteria colonies have been analyzed by laser-induced breakdown spectroscopy using nanosecond laser pulses. LIBS spectra were obtained after transferring the bacteria from a nutrient-rich culture medium to a nutrient-free agar plate for laser ablation. To study the dependence of the LIBS spectrum on growth and environmental conditions, colonies were cultured on three different nutrient media: a trypticase soy agar (TSA) plate, a blood agar plate, and a medium chosen deliberately to induce bacteria membrane changes, a MacConkey agar plate containing bile salts. Nineteen atomic and ionic emission lines in the LIBS spectrum, which was dominated by inorganic elements such as calcium, magnesium and sodium, were used to identify and classify the bacteria. A discriminant function analysis was used to discriminate between the P. aeruginosa bacteria and two strains of E. coli: a non-pathogenic environmental strain and the pathogenic strain enterohemorrhagic E. coli 0157:H7 (EHEC). Nearly identical spectra were obtained from P. aeruginosa grown on the TSA plate and the blood agar plate, while the bacteria grown on the MacConkey plate exhibited easily distinguishable differences from the other two. All P. aeruginosa samples, independent of initial growth conditions, were readily discriminated from the two E. coli strains.

  15. Initial Host Response to Bacteria in the Murine Lung Differs Between Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pneumoniae.

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    Preu, Liselotte; Bischoff, Markus; Veith, Nils T; Rosenbruch, Martin; Theegarten, Dirk; Laschke, Matthias W; Meier, Carola; Tschernig, Thomas

    2016-04-01

    Phagocytosis of bacteria is an important process during early host defence. It has been directly observed only ex vivo or in vitro. Here, we report on the observation of phagocytosis under in vivo conditions by using intravital microscopy in the murine lung. Suspensions of fluorescently labelled Streptococcus pneumoniae, Staphylococcus aureus and Pseudomonas aeruginosa cells were each instilled intratracheally to anaesthetized mice. After thoracotomy, the alveolar surface was observed for 30 min. Alveolar phagocytes exhibiting ingested bacteria could be detected and counted. The highest numbers were found after the infection with P. aeruginosa. By using intravital microscopy, cellular host defence could be observed in living mice lungs. The initial phagocytic reaction crucially depends on the species of applied bacteria invading the lung.

  16. Inhibition of quorum sensing in Pseudomonas aeruginosa biofilm bacteria by a halogenated furanone compound

    DEFF Research Database (Denmark)

    Hentzer, Morten; Riedel, K.; Rasmussen, Thomas Bovbjerg

    2002-01-01

    Novel molecular tools have been constructed which allow for in situ detection of N-acyl homoserine lactone (AHL)-mediated quorum sensing in Pseudomonas aeruginosa biofilms. The reporter responds to AHL activation of LasR lay expression of an unstable version of the green-fluorescent protein (Gfp......). Gfp-based reporter technology has been applied for non-destructive, single-cell-level detection of quorum sensing in laboratory-based P. aeruginosa biofilms. It is reported that a synthetic halogenated furanone compound, which is a derivative of the secondary metabolites produced by the Australian...... macroalga Delisea pulchra, is capable of interfering with AHL-mediated quorum sensing in P. aeruginosa. It is demonstrated that the furanone compound specifically represses expression of a PlasB-gfp reporter fusion without affecting growth or protein synthesis. In addition, it reduces the production...

  17. 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...

  18. Mannitol enhances antibiotic sensitivity of persister bacteria in Pseudomonas aeruginosa biofilms.

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    Nicolas Barraud

    Full Text Available The failure of antibiotic therapies to clear Pseudomonas aeruginosa lung infection, the key mortality factor for cystic fibrosis (CF patients, is partly attributed to the high tolerance of P. aeruginosa biofilms. Mannitol has previously been found to restore aminoglycoside sensitivity in Escherichia coli by generating a proton-motive force (PMF, suggesting a potential new strategy to improve antibiotic therapy and reduce disease progression in CF. Here, we used the commonly prescribed aminoglycoside tobramycin to select for P. aeruginosa persister cells during biofilm growth. Incubation with mannitol (10-40 mM increased tobramycin sensitivity of persister cells up to 1,000-fold. Addition of mannitol to pre-grown biofilms was able to revert the persister phenotype and improve the efficacy of tobramycin. This effect was blocked by the addition of a PMF inhibitor or in a P. aeruginosa mutant strain unable to metabolise mannitol. Addition of glucose and NaCl at high osmolarity also improved the efficacy of tobramycin although to a lesser extent compared to mannitol. Therefore, the primary effect of mannitol in reverting biofilm associated persister cells appears to be an active, physiological response, associated with a minor contribution of osmotic stress. Mannitol was tested against clinically relevant strains, showing that biofilms containing a subpopulation of persister cells are better killed in the presence of mannitol, but a clinical strain with a high resistance to tobramycin was not affected by mannitol. Overall, these results suggest that in addition to improvements in lung function by facilitating mucus clearance in CF, mannitol also affects antibiotic sensitivity in biofilms and does so through an active, physiological response.

  19. Mannitol Enhances Antibiotic Sensitivity of Persister Bacteria in Pseudomonas aeruginosa Biofilms

    Science.gov (United States)

    Barraud, Nicolas; Buson, Alberto; Jarolimek, Wolfgang; Rice, Scott A.

    2013-01-01

    The failure of antibiotic therapies to clear Pseudomonas aeruginosa lung infection, the key mortality factor for cystic fibrosis (CF) patients, is partly attributed to the high tolerance of P. aeruginosa biofilms. Mannitol has previously been found to restore aminoglycoside sensitivity in Escherichia coli by generating a proton-motive force (PMF), suggesting a potential new strategy to improve antibiotic therapy and reduce disease progression in CF. Here, we used the commonly prescribed aminoglycoside tobramycin to select for P. aeruginosa persister cells during biofilm growth. Incubation with mannitol (10–40 mM) increased tobramycin sensitivity of persister cells up to 1,000-fold. Addition of mannitol to pre-grown biofilms was able to revert the persister phenotype and improve the efficacy of tobramycin. This effect was blocked by the addition of a PMF inhibitor or in a P. aeruginosa mutant strain unable to metabolise mannitol. Addition of glucose and NaCl at high osmolarity also improved the efficacy of tobramycin although to a lesser extent compared to mannitol. Therefore, the primary effect of mannitol in reverting biofilm associated persister cells appears to be an active, physiological response, associated with a minor contribution of osmotic stress. Mannitol was tested against clinically relevant strains, showing that biofilms containing a subpopulation of persister cells are better killed in the presence of mannitol, but a clinical strain with a high resistance to tobramycin was not affected by mannitol. Overall, these results suggest that in addition to improvements in lung function by facilitating mucus clearance in CF, mannitol also affects antibiotic sensitivity in biofilms and does so through an active, physiological response. PMID:24349568

  20. Chronic Pseudomonas aeruginosa cervical osteomyelitis

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    Sujeet Kumar Meher

    2016-01-01

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

  1. Microcystis aeruginosa/Pseudomonas pseudoalcaligenes interaction effects on off-flavors in algae/bacteria co-culture system under different temperatures.

    Science.gov (United States)

    Yang, Xi; Xie, Ping; Yu, Yunzhen; Shen, Hong; Deng, Xuwei; Ma, Zhimei; Wang, Peili; Tao, Min; Niu, Yuan

    2015-05-01

    We conducted an experiment to study the interaction effects of Microcystis aeruginosa and Pseudomonas pseudoalcaligenes on off-flavors in an algae/bacteria co-culture system at three temperatures (24, 28 and 32°C). Gas chromatography-mass spectrometry was applied to measure off-flavor compounds dimethyl sulfide (DMS), dimethyl trisulfide (DMTS), 2-methylisoborneol, geosmin (GEO) and β-cyclocitral. During the lag phase of co-cultured M. aeruginosa (first 15days), P. pseudoalcaligenes significantly increased the production of DMS, DMTS and β-cyclocitral at all three temperatures. In the exponential phase of co-cultured M. aeruginosa (after 15days), M. aeruginosa became the main factor on off-flavors in the co-culture system, and β-cyclocitral turned to the highest off-flavor compound. These results also indicated that DMS, DMTS and β-cyclocitral were the main off-flavor compounds in our M. aeruginosa/P. pseudoalcaligenes co-culture system. Univariate analysis was applied to investigate the effects of M. aeruginosa and P. pseudoalcaligenes on the production of off-flavors. The results demonstrated that both M. aeruginosa and P. pseudoalcaligenes could increase the production of DMS and DMTS, while β-cyclocitral was mainly determined by M. aeruginosa. Our results also provide some insights into understanding the relationship between cyanobacteria and heterotrophic bacteria. Copyright © 2015. Published by Elsevier B.V.

  2. Biosynthesis of pyocyanin pigment by Pseudomonas aeruginosa

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    M.Z. El-Fouly

    2015-01-01

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

  3. Complement activation by Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

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

    1993-01-01

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

  4. Pseudomonas Aeruginosa Toxins

    Science.gov (United States)

    1982-09-01

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

  5. The immune system vs. Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  6. Nosocomial outbreak of Pseudomonas aeruginosa endophthalmitis.

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

    2006-11-01

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

  7. Pseudomonas aeruginosa septicemia

    OpenAIRE

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

    2014-01-01

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

  8. Pseudomonas aeruginosa biofilms in cystic fibrosis

    DEFF Research Database (Denmark)

    Høiby, Niels; Ciofu, Oana; Bjarnsholt, Thomas

    2010-01-01

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

  9. Colony to colorimetry in 6 h: ELISA detection of a surface-expressed Pseudomonas aeruginosa virulence factor using immobilized bacteria.

    Science.gov (United States)

    Adawi, Azmi; Neville, Lewis F

    2012-09-01

    A rapid ELISA employing intact Pseudomonas aeruginosa (PA) is described that allows discrimination between strains harboring flagellin type a or b. All 52 PA strains known to harbor flagellin type b were positive in this ELISA when screened with a fully human monoclonal antibody (LST-007) targeting flagellin type b. Completion of this assay in only 6 h, from picking a single bacterial colony to a colorimetric product, could easily be adapted to a clinical laboratory setting and permit the appropriate choice of therapeutic monoclonal antibody versus its homologous flagellin target in PA-infected patients. Copyright © 2012 Elsevier Inc. All rights reserved.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  11. Cell death in Pseudomonas aeruginosa biofilm development

    DEFF Research Database (Denmark)

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

    2003-01-01

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

  12. Results from a 13-Year Prospective Cohort Study Show Increased Mortality Associated with Bloodstream Infections Caused by Pseudomonas aeruginosa Compared to Other Bacteria.

    Science.gov (United States)

    Thaden, Joshua T; Park, Lawrence P; Maskarinec, Stacey A; Ruffin, Felicia; Fowler, Vance G; van Duin, David

    2017-06-01

    The impact of bacterial species on outcome in bloodstream infections (BSI) is incompletely understood. We evaluated the impact of bacterial species on BSI mortality, with adjustment for patient, bacterial, and treatment factors. From 2002 to 2015, all adult inpatients with monomicrobial BSI caused by Staphylococcus aureus or Gram-negative bacteria at Duke University Medical Center were prospectively enrolled. Kaplan-Meier curves and multivariable Cox regression with propensity score models were used to examine species-specific bacterial BSI mortality. Of the 2,659 enrolled patients, 999 (38%) were infected with S. aureus, and 1,660 (62%) were infected with Gram-negative bacteria. Among patients with Gram-negative BSI, Enterobacteriaceae (81% [1,343/1,660]) were most commonly isolated, followed by non-lactose-fermenting Gram-negative bacteria (16% [262/1,660]). Of the 999 S. aureus BSI isolates, 507 (51%) were methicillin resistant. Of the 1,660 Gram-negative BSI isolates, 500 (30%) were multidrug resistant. The unadjusted time-to-mortality among patients with Gram-negative BSI was shorter than that of patients with S. aureus BSI (P = 0.003), due to increased mortality in patients with non-lactose-fermenting Gram-negative BSI generally (P < 0.0001) and Pseudomonas aeruginosa BSI (n = 158) in particular (P < 0.0001). After adjustment for patient demographics, medical comorbidities, bacterial antibiotic resistance, timing of appropriate antibiotic therapy, and source control in patients with line-associated BSI, P. aeruginosa BSI remained significantly associated with increased mortality (hazard ratio = 1.435; 95% confidence interval = 1.043 to 1.933; P = 0.02). P. aeruginosa BSI was associated with increased mortality relative to S. aureus or other Gram-negative BSI. This effect persisted after adjustment for patient, bacterial, and treatment factors. Copyright © 2017 American Society for Microbiology.

  13. Pseudomonas aeruginosa outcompetes other bacteria in the manifestation and maintenance of a biofilm in polyvinylchloride tubing as used in dental devices.

    Science.gov (United States)

    Ammann, Christoph Gert; Nagl, Markus; Nogler, Michael; Coraça-Huber, Débora Cristina

    2016-05-01

    In a PVC tube as a model system for dental devices, Pseudomonas aeruginosa outcompetes Staphylococcus aureus and Klebsiella pneumoniae for the biofilm formation. P. aeruginosa has advantage over the other strains due to higher tolerance for low-nutrient situations or direct killing by the production of soluble factors like pyocyanin.

  14. Dynamics of Pseudomonas aeruginosa Genome Evolution

    National Research Council Canada - National Science Library

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

    2008-01-01

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

  15. Pseudomonas aeruginosa: resistance to the max

    National Research Council Canada - National Science Library

    Poole, Keith

    2011-01-01

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

  16. Antibiotic Conditioned Growth Medium of Pseudomonas Aeruginosa

    Science.gov (United States)

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

    2004-01-01

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

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

    African Journals Online (AJOL)

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

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

    DEFF Research Database (Denmark)

    Wu, Hong; Lee, Baoleri; Yang, Liang

    2011-01-01

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

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

    DEFF Research Database (Denmark)

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

    1993-01-01

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

  20. Antivirulence activity of azithromycin in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Francesco eImperi

    2014-04-01

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

  1. High Temperature Induced Antibiotic Sensitivity in Pseudomonas aeruginosa.

    Science.gov (United States)

    1984-08-01

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

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

    Science.gov (United States)

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

    2008-07-01

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

  3. Role of the lysozyme inhibitor Ivy in growth or survival of Escherichia coli and Pseudomonas aeruginosa bacteria in hen egg white and in human saliva and breast milk.

    Science.gov (United States)

    Deckers, Daphne; Vanlint, Dietrich; Callewaert, Lien; Aertsen, Abram; Michiels, Chris W

    2008-07-01

    Ivy is a lysozyme inhibitor that protects Escherichia coli against lysozyme-mediated cell wall hydrolysis when the outer membrane is permeabilized by mutation or by chemical or physical stress. In the current work, we have investigated whether Ivy is necessary for the survival or growth of E. coli MG1655 and Pseudomonas aeruginosa PAO1 in hen egg white and in human saliva and breast milk, which are naturally rich in lysozyme and in membrane-permeabilizing components. Wild-type E. coli was able to grow in saliva and breast milk but showed partial inactivation in egg white. The knockout of Ivy did not affect growth in breast milk but slightly increased sensitivity to egg white and caused hypersensitivity to saliva, resulting in the complete inactivation of 10(4) CFU ml(-1) of bacteria within less than 5 hours. The depletion of lysozyme from saliva completely restored the ability of the ivy mutant to grow like the parental strain. P. aeruginosa, in contrast, showed growth in all three substrates, which was not affected by the knockout of Ivy production. These results indicate that lysozyme inhibitors like Ivy promote bacterial survival or growth in particular lysozyme-rich secretions and suggest that they may promote the bacterial colonization of specific niches in the animal host.

  4. Risk assessment of Pseudomonas aeruginosa in water.

    Science.gov (United States)

    Mena, Kristina D; Gerba, Charles P

    2009-01-01

    P. aeruginosa is part of a large group of free-living bacteria that are ubiquitous in the environment. This organism is often found in natural waters such as lakes and rivers in concentrations of 10/100 mL to >1,000/100 mL. However, it is not often found in drinking water. Usually it is found in 2% of samples, or less, and at concentrations up to 2,300 mL(-1) (Allen and Geldreich 1975) or more often at 3-4 CFU/mL. Its occurrence in drinking water is probably related more to its ability to colonize biofilms in plumbing fixtures (i.e., faucets, showerheads, etc.) than its presence in the distribution system or treated drinking water. P. aeruginosa can survive in deionized or distilled water (van der Jooij et al. 1982; Warburton et al. 1994). Hence, it may be found in low nutrient or oligotrophic environments, as well as in high nutrient environments such as in sewage and in the human body. P. aeruginosa can cause a wide range of infections, and is a leading cause of illness in immunocompromised individuals. In particular, it can be a serious pathogen in hospitals (Dembry et al. 1998). It can cause endocarditis, osteomyelitis, pneumonia, urinary tract infections, gastrointestinal infections, and meningitis, and is a leading cause of septicemia. P. aeruginosa is also a major cause of folliculitis and ear infections acquired by exposure to recreational waters containing the bacterium. In addition, it has been recognized as a serious cause of keratitis, especially in patients wearing contact lenses. P. aeruginosa is also a major pathogen in burn and cystic fibrosis (CF) patients and causes a high mortality rate in both populations (MOlina et al. 1991; Pollack 1995). P. aeruginosa is frequently found in whirlpools and hot tubs, sometimes in 94-100% of those tested at concenrations of ozone, or iodine. One author, however, did find it to be slightly more resistant to UV disinfection than most other bacteria (Wolfe 1990). Although much has been written about biofilms in the

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

    Science.gov (United States)

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

    2013-02-01

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

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

    Science.gov (United States)

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

    2015-03-01

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

  7. Chromosomal organization and segregation in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Isabelle Vallet-Gely

    2013-05-01

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

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

    DEFF Research Database (Denmark)

    Johansen, Helle Krogh; Gøtzsche, Peter C

    2013-01-01

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

  9. Airway epithelial cell tolerance to Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Verghese Margrith W

    2005-04-01

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

  10. Interaction of protamine with gram-negative bacteria membranes: possible alternative mechanisms of internalization in Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa.

    Science.gov (United States)

    Pink, David A; Hasan, Fida M; Quinn, Bonnie E; Winterhalter, Mathias; Mohan, Mukund; Gill, Tom A

    2014-04-01

    This study was concerned with the interaction between the cationic antimicrobial peptide, protamine (Ptm) and the cytoplasmic membranes of the gram-negative bacteria Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa. The objective of the study was to explain the observed paradox of internalization without permanent disruption of the cell envelope. We carried out Monte Carlo computer simulation of Ptm in an aqueous environment in the presence of ~100 mM NaCl and model membranes consisting of either (65:35) or (75:25) PE:PG molar ratios. The (75:25) model, representative of the gram-negative cytoplasmic membrane, showed that the Ptm center of mass remained at least 7 nm from the membrane surface leading to the prediction that Ptm would not internalize via disruption of the inner membrane. By using immunoelectron microscopy of Ptm-treated cells, we showed that Ptm internalization to the cytoplasm took place rapidly in the presence or absence of the outer envelope. Ultrastructural examination revealed no obvious morphological changes to cells that were treated with subinhibitory or bactericidal levels of Ptm. Reconstituted phospholipid bilayers were constructed and were unperturbed by Ptm treatment over a wide range of concentrations and applied transmembrane voltages. We conclude that in the cases of the cell envelopes of E. coli, S. typhimurium and P. aeruginosa, Ptm internalized by means independent of the phospholipid bilayer, most likely mediated by one or more membrane proteins such as cation-selective barrel-like proteins. Work is currently underway to test this hypothesis. © 2014 The Authors. Journal of Peptide Science published by John Wiley & Sons, Ltd.

  11. Stratified growth in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

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

    2004-01-01

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

  12. Mechanisms of phagocytosis and host clearance of Pseudomonas aeruginosa

    Science.gov (United States)

    Lovewell, Rustin R.; Patankar, Yash R.

    2014-01-01

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

  13. Interspecies Interaction between Pseudomonas aeruginosa and Other Microorganisms

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2009-09-01

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

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

    Science.gov (United States)

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

    1992-06-01

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

  16. Antibiotics Susceptibility Pattern of Pseudomonas aeruginosa ...

    African Journals Online (AJOL)

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

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

    African Journals Online (AJOL)

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

  18. Pseudomonas aeruginosa PA14 pathogenesis in Caenorhabditis elegans.

    Science.gov (United States)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2014-07-18

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

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

    Directory of Open Access Journals (Sweden)

    Garry Laverty

    2014-07-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  2. Non-susceptibility trends among Pseudomonas aeruginosa and other non-fermentative Gram-negative bacteria from bacteraemias in the UK and Ireland, 2001-06.

    Science.gov (United States)

    Livermore, David M; Hope, Russell; Brick, Geraldine; Lillie, Mark; Reynolds, Rosy

    2008-11-01

    Pseudomonas and Acinetobacter spp. are important opportunists, notorious for resistance. Pseudomonas spp. are collected in the British Society for Antimicrobial Chemotherapy (BSAC) bacteraemia surveillance, with Acinetobacter spp. and Stenotrophomonas maltophilia well represented in the 'other Gram-negatives' group. Data for collected isolates were reviewed together with LabBase bacteraemia reports to the Health Protection Agency (HPA). Isolates with unusual resistances were subjected to molecular investigation. From 2001 to 2006, the BSAC surveillance collected 1226 Pseudomonas aeruginosa, 240 Acinetobacter spp.-125 of them Acinetobacter calcoaceticus/baumannii (Acb) complex-and 165 S. maltophilia. Among P. aeruginosa, non-susceptibility rates to beta-lactams and gentamicin fluctuated, without trend, below 10%; those to ciprofloxacin ranged from 16% to 22%. One P. aeruginosa isolate from 2001 had VIM-2 metallo-beta-lactamase. For Acb, the BSAC data indicated frequent non-susceptibility, except to imipenem, where only five non-susceptible isolates were collected, all after 2003, four of them belonging to the OXA-23 clone 1 lineage which is prevalent in Southeast England. Reports to the HPA indicated rising imipenem non-susceptibility in Acb (P /=16 mg/L for Acb OXA-23 clone 1. Ceftobiprole had higher MICs than ceftazidime for P. aeruginosa, but 81% of the isolates were inhibited at aeruginosa from bacteraemias in the UK and Ireland remain relatively susceptible by international standards; in contrast, multiresistance is widespread in Acb, with imipenem non-susceptibility emerging.

  3. Electrochemical reduction of oxygen catalyzed by Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  4. Pseudomonas aeruginosa in Musca domestica L.: temporospatial examination of bacteria population dynamics and house fly antimicrobial responses

    Science.gov (United States)

    House flies associate with microbes throughout their life history. Bacteria ingested by adult flies enter the alimentary canal and face a hostile environment including antimicrobial defenses. Because the outcome of this interaction impacts bacterial survival and dissemination, our primary objective ...

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

    Directory of Open Access Journals (Sweden)

    Kiran Chawla

    2015-01-01

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

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

    Science.gov (United States)

    Mukherjee, Munmun; De, Sirshendu

    2016-01-01

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

  7. Attenuation of Pseudomonas aeruginosa virulence by quorum sensing inhibitors

    DEFF Research Database (Denmark)

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

    2003-01-01

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

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

    DEFF Research Database (Denmark)

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

    2017-01-01

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

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

    Science.gov (United States)

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

    2017-11-15

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

  10. Penicillin V acylases from gram-negative bacteria degrade N-acylhomoserine lactones and attenuate virulence in Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Sunder, Avinash Vellore; Utari, Putri Dwi; Ramasamy, Sureshkumar; van Merkerk, Ronald; Quax, Wim J.; Pundle, Archana

    Virulence pathways in gram-negative pathogenic bacteria are regulated by quorum sensing mechanisms, through the production and sensing of N-acylhomoserine lactone (AHL) signal molecules. Enzymatic degradation of AHLs leading to attenuation of virulence (quorum quenching) could pave the way for the

  11. Cooperative production of siderophores by Pseudomonas aeruginosa.

    Science.gov (United States)

    Harrison, Freya; Buckling, Angus

    2009-01-01

    The production of iron-scavenging siderophores by the opportunistic animal pathogen Pseudomonas aeruginosa is a textbook example of public goods cooperation. This trait provides an excellent model system with which to study cooperation. Further, the links between siderophore production and P. aeruginosa virulence allow us to investigate how pathogen ecology, social behaviour and pathology might be connected. We present here the results of basic research on the evolution and ecology of siderophore cooperation in this species. In particular, we explore the effects of population and community structure, iron regime and genomic mutation rate on the relative success of siderophore cooperators and cheats. We also present preliminary data on the links between siderophore production and another clinically-relevant social trait, biofilm formation. It is our hope that more realistic laboratory studies of siderophore cooperation in P. aeruginosa will eventually cast light on the roles played by social traits in long-term microbial infections.

  12. Pseudomonas aeruginosa Dose-Response and Bathing Water Infection

    Science.gov (United States)

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

  13. Alginate overproduction affects Pseudomonas aeruginosa biofilm structure and function

    DEFF Research Database (Denmark)

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

    2001-01-01

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

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

    OpenAIRE

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

    2005-01-01

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

  15. The implication of Pseudomonas aeruginosa biofilms in infections

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  16. Flagellation of Pseudomonas aeruginosa in newly divided cells

    Science.gov (United States)

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

    2015-03-01

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

  17. The implication of Pseudomonas aeruginosa biofilms in infections

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  18. Standardized chemical synthesis of Pseudomonas aeruginosa pyocyanin

    Directory of Open Access Journals (Sweden)

    Rajkumar Cheluvappa

    2014-01-01

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

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

    Science.gov (United States)

    Yu, Shan; Ma, Luyan

    2017-09-25

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

  20. Mature Pseudomonas aeruginosa biofilms prevail compared to young biofilms in the presence of ceftazidime.

    Science.gov (United States)

    Bowler, Laura L; Zhanel, George G; Ball, T Blake; Saward, Laura L

    2012-09-01

    Phenotypic tolerances to antibiotics of mature and young Pseudomonas aeruginosa PAO1 biofilms and released planktonic bacteria were compared for four antibiotics. Resistance levels were similar for gentamicin and ciprofloxacin but differed for ceftazidime and meropenem. β-Lactamase mapping showed that, after 5 h of ceftazidime exposure, mature biofilms produced more β-lactamase than young biofilms, facilitating the growth of released planktonic bacteria. This shows the importance of early treatment and choice of antibiotics for P. aeruginosa biofilm infections.

  1. Quorum quenching activity in cell-free lysate of endophytic bacteria isolated from Pterocarpus santalinus Linn., and its effect on quorum sensing regulated biofilm in Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Rajesh, P S; Ravishankar Rai, V

    2014-01-01

    Quorum sensing mechanism allows the microorganisms to resist the antibiotic treatment by forming biofilms. Quorum quenching is one of the mechanisms to control the development of drug resistance in microbes. Endophyte bacteria are beneficial to plant growth as they support the immune system against the pathogen attack. The endophytic bacteria present in Pterocarpus santalinus were screened for the presence of N-acyl homoserine lactones (AHLs) degrading bacteria using biosensor strains and further confirmed by quantifying the violacein production. Cell-free lysate of endophytic bacteria, Bacillus firmus PT18 and Enterobacter asburiae PT39 exhibited potent AHL degrading ability by inhibiting about 80% violacein production in biosensor strain. Furthermore, when the cell-free lysate was applied to Pseudomonas aeruginosa PAO1 and PAO1-JP2 biofilm it resulted in significant (p<0.01) inhibition of biofilm formation. The biofilm inhibition was confirmed by visualization of biofilm slides under fluorescence microscopy, which showed decrease in total biomass formation in treated slides. Isolation and amplification of the gene (aiiA) indicated that the presence of AHL lactonase in cell-free lysate and sequence alignment indicated that AiiA contains a "HXHXDH" zinc-binding motif that is being conserved in several groups of metallohydrolases. Therefore, the study shows the potential of AHLs degradation by AHL lactonase present in cell-free lysate of isolated endophytic bacteria and inhibition of quorum sensing regulated biofilm formation in P. aeruginosa PAO1. Copyright © 2013 Elsevier GmbH. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Mary E. Peek

    2012-01-01

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

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

    Science.gov (United States)

    Priebe, Gregory P.; Goldberg, Joanna B.

    2015-01-01

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

  4. Pseudomonas aeruginosa endophthalmitis masquerading as chronic uveitis

    Directory of Open Access Journals (Sweden)

    Kalpana Badami Nagaraj

    2013-01-01

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

  5. 33 original article infections a pseudomonas aeruginosa dans un ...

    African Journals Online (AJOL)

    boaz

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

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

    DEFF Research Database (Denmark)

    Marvig, Rasmus Lykke

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

  7. Role of mutation in Pseudomonas aeruginosa biofilm development.

    Directory of Open Access Journals (Sweden)

    Tim C R Conibear

    2009-07-01

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

  8. Gene expression in Pseudomonas aeruginosa swarming motility

    Directory of Open Access Journals (Sweden)

    Déziel Eric

    2010-10-01

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

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

    Science.gov (United States)

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

    2016-03-01

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

  10. Biotransformation of myrcene by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Hashemi Elham

    2011-05-01

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

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

    DEFF Research Database (Denmark)

    Andersen, A S; Jørgensen, Bo; Bjarnsholt, T

    2010-01-01

    Maggot debridement therapy (MDT) is widely used for debridement of chronic infected wounds; however, for wounds harbouring specific bacteria limited effect or failure of the treatment has been described. Here we studied the survival of Lucilia sericata maggots encountering Pseudomonas aeruginosa...... for the presence of QS inhibitors; only high doses of ES showed inhibition of QS in P. aeruginosa. Thus P. aeruginosa was shown to be toxic to L. sericata maggots. This, coupled to the preferential feeding by the maggots and reduced ingestion of P. aeruginosa, could explain MDT failure in wounds colonized by P...

  12. Effect of Catechins, Green tea Extract and Methylxanthines in Combination with Gentamicin Against Staphylococcus aureus and Pseudomonas aeruginosa - Combination therapy against resistant bacteria -

    Directory of Open Access Journals (Sweden)

    Bibi Sedigheh Fazly Bazzaz

    2016-12-01

    Full Text Available Objectives: Bacterial resistant infections have become a global health challenge and threaten the society’s health. Thus, an urgent need exists to find ways to combat resistant pathogens. One promising approach to overcoming bacterial resistance is the use of herbal products. Green tea catechins, the major green tea polyphenols, show antimicrobial activity against resistant pathogens. The present study aimed to investigate the effect of catechins, green tea extract, and methylxanthines in combination with gentamicin against standard and clinical isolates of Staphylococcus aureus (S. aureus and the standard strain of Pseudomonas aeruginosa (P. aeruginosa. Methods: The minimum inhibitory concentration (MIC and the minimum bactericidal concentration (MBC values of different agents against bacterial strains were determined. The interactions of green tea extract, epigallate catechin, epigallocatechin gallate, two types of methylxanthine, caffeine, and theophylline with gentamicin were studied in vitro by using a checkerboard method and calculating the fraction inhibitory concentration index (FICI. Results: The MICs of gentamicin against bacterial strains were in the range of 0.312 - 320 μg/mL. The MIC values of both types of catechins were 62.5 - 250 μg/ mL. Green tea extract showed insufficient antibacterial activity when used alone. Methylxanthines had no intrinsic inhibitory activity against any of the bacterial strains tested. When green tea extract and catechins were combined with gentamicin, the MIC values of gentamicin against the standard strains and a clinical isolate were reduced, and synergistic activities were observed (FICI < 1. A combination of caffeine with gentamicin did not alter the MIC values of gentamicin. Conclusion: The results of the present study revealed that green tea extract and catechins potentiated the antimicrobial action of gentamicin against some clinical isolates of S. aureus and standard P. aeruginosa strains

  13. Multi-functional characteristics of the Pseudomonas aeruginosa type III needle-tip protein, PcrV; comparison to orthologs in other gram negative bacteria

    Directory of Open Access Journals (Sweden)

    Hiromi eSato

    2011-07-01

    Full Text Available Pseudomonas aeruginosa possesses a type III secretion system (T3SS to intoxicate host cells and evade innate immunity. This virulence-related machinery consists of a molecular syringe and needle assembled on the bacterial surface, which allows delivery of T3 effector proteins into infected cells. To accomplish a one-step effector translocation, a tip protein is required at the top end of the T3 needle structure. Strains lacking expression of the functional tip protein fail to intoxicate host cells.P. aeruginosa encodes a T3S that is highly homologous to the proteins encoded by Yersinia species. The needle tip proteins of Yersinia, LcrV, and P. aeruginosa, PcrV, share 37% identity and 65% similarity. Other known tip proteins are AcrV (Aeromonas, IpaD (Shigella, SipD (Salmonella, BipD (Burkholderia, EspA (EPEC, EHEC, Bsp22 (Bordetella, with additional proteins identified from various Gram negative species, such as Vibrio and Bordetella. The tip proteins can serve as a protective antigen or may be critical for sensing host cells and evading innate immune responses. Recognition of the host microenvironment transcriptionally activates synthesis of T3SS components. The machinery appears to be mechanically controlled by the assemblage of specific junctions within the apparatus. These junctions include the tip and base of the T3 apparatus, the needle proteins and components within the bacterial cytoplasm. The tip proteins likely have chaperone functions for translocon proteins, allowing the proper assembly of translocation channels in the host membrane and completing vectorial delivery of effector proteins into the host cytoplasm. Multifunctional features of the needle-tip proteins appear to be intricately controlled. In this review, we highlight the functional aspects and complex controls of T3 needle-tip proteins with particular emphasis on PcrV and LcrV.

  14. Therapy of Pseudomonas aeruginosa infections with tobramycin.

    Science.gov (United States)

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

    1975-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Šarūnas Paškevičius

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

  16. The Mechanism of Killing by the Proline-Rich Peptide Bac7(1-35) against Clinical Strains of Pseudomonas aeruginosa Differs from That against Other Gram-Negative Bacteria.

    Science.gov (United States)

    Runti, Giulia; Benincasa, Monica; Giuffrida, Grazia; Devescovi, Giulia; Venturi, Vittorio; Gennaro, Renato; Scocchi, Marco

    2017-04-01

    Pseudomonas aeruginosa infections represent a serious threat to worldwide health. Proline-rich antimicrobial peptides (PR-AMPs), a particular group of peptide antibiotics, have demonstrated in vitro activity against P. aeruginosa strains. Here we show that the mammalian PR-AMP Bac7(1-35) is active against some multidrug-resistant cystic fibrosis isolates of P. aeruginosa By confocal microscopy and cytometric analyses, we investigated the mechanism of killing against P. aeruginosa strain PAO1 and three selected isolates, and we observed that the peptide inactivated the target cells by disrupting their cellular membranes. This effect is deeply different from that previously described for PR-AMPs in Escherichia coli and Salmonella enterica serovar Typhimurium, where these peptides act intracellularly after having been internalized by means of the transporter SbmA without membranolytic effects. The heterologous expression of SbmA in PAO1 cells enhanced the internalization of Bac7(1-35) into the cytoplasm, making the bacteria more susceptible to the peptide but at the same time more resistant to the membrane lysis, similarly to what occurs in E. coli The results evidenced a new mechanism of action for PR-AMPs and indicate that Bac7 has multiple and variable modes of action that depend on the characteristics of the different target species and the possibility to be internalized by bacterial transporters. This feature broadens the spectrum of activity of the peptide and makes the development of peptide-resistant bacteria a more difficult process. Copyright © 2017 American Society for Microbiology.

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Zainal Abidin Ali

    2014-01-01

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

  19. Targeting quorum sensing in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

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

    2013-01-01

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

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

    DEFF Research Database (Denmark)

    Johansen, Helle Krogh; Gøtzsche, Peter C

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Faiqah Umar

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Gómez Álvarez

    2005-01-01

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

  3. Bioalteration of synthetic Fe(III)-, Fe(II)-bearing basaltic glasses and Fe-free glass in the presence of the heterotrophic bacteria strain Pseudomonas aeruginosa: Impact of siderophores

    Science.gov (United States)

    Perez, Anne; Rossano, Stéphanie; Trcera, Nicolas; Huguenot, David; Fourdrin, Chloé; Verney-Carron, Aurélie; van Hullebusch, Eric D.; Guyot, François

    2016-09-01

    This study aims to evaluate the role of micro-organisms and their siderophores in the first steps of the alteration processes of basaltic glasses in aqueous media. In this regard, three different types of glasses - with or without iron, in the reduced Fe(II) or oxidized Fe(III) states - were prepared on the basis of a simplified basaltic glass composition. Control and Pseudomonas aeruginosa inoculated experiments were performed in a buffered (pH 6.5) nutrient depleted medium to stimulate the production of the pyoverdine siderophore. Results show that the presence of P. aeruginosa has an effect on the dissolution kinetics of all glasses as most of the calculated elemental release rates are increased compared to sterile conditions. Reciprocally, the composition of the glass in contact with P. aeruginosa has an impact on the bacterial growth and siderophore production. As an essential nutrient for this microbial strain, Fe notably appears to play a central role during biotic experiments. Its presence in the glass stimulates the bacterial growth and minimizes the synthesis of pyoverdine. Moreover the initial Fe2+/Fe3+ ratio in the glasses modulates this synthesis, as pyoverdine is not detected at all in the system in contact with Fe(III)-bearing glass. Finally, the dissolution rates appear to be correlated to siderophore concentrations as they increase with respect to sterile experiments in the order Fe(III)-bearing glass siderophores and Fe or Al for Fe(II)-bearing glass or Fe-free glass, respectively. The dissolution of an Fe-free glass is significantly improved in the presence of bacteria, as initial dissolution rates are increased by a factor of 3. This study attests to the essential role of siderophores in the P. aeruginosa-promoted dissolution processes of basaltic glasses as well as to the complex relationships between the nutritional potential of the glass and its dissolution rates.

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

    Science.gov (United States)

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

    2016-04-01

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

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

    African Journals Online (AJOL)

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

  6. The Enzymes of the Ammonia Assimilation in Pseudomonas aeruginosa

    NARCIS (Netherlands)

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

    1980-01-01

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

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

    African Journals Online (AJOL)

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

  8. Caenorhabditis elegans reveals novel Pseudomonas aeruginosa virulence mechanism

    NARCIS (Netherlands)

    Utari, Putri Dwi; Quax, Wim J.

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

  9. Sequencing and characterization of Pseudomonas aeruginosa phage JG004

    National Research Council Canada - National Science Library

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

    2011-01-01

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

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

    National Research Council Canada - National Science Library

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

    2013-01-01

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

  11. Characterization of Glutamine-Requiring Mutants of Pseudomonas aeruginosa

    NARCIS (Netherlands)

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

    1982-01-01

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

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

    OpenAIRE

    Nakahara, H; Kozukue, H

    1982-01-01

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

  13. Hyperbaric oxygen sensitizes anoxic Pseudomonas aeruginosa biofilm to ciprofloxacin

    DEFF Research Database (Denmark)

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

    2017-01-01

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

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

    DEFF Research Database (Denmark)

    Bagge, N.; Hentzer, Morten; Andersen, Jens Bo

    2004-01-01

    The development of resistance to beta-lactam antibiotics is a problem in the treatment of chronic Pseudomonas aeruginosa infection in the lungs of patients with cystic fibrosis. The main resistance mechanism is high-level expression of the chromosomally encoded AmpC beta-lactamase of P. aeruginosa...... of the ampC promoter to gfp(ASV) encoding an unstable version of the green fluorescent protein. In vitro biofilms of P. aeruginosa were exposed to the beta-lactam antibiotics imipenem and ceftazidime. Sub-MICs of imipenem significantly induced the monitor system of the biofilm bacteria in the peripheries...... distributions of beta-lactamase induction in P. aeruginosa cells growing in biofilms. Thus, our experiments show that P. aeruginosa cells growing in biofilms constitute a heterogeneous population unit which may create different antibiotic-selective environments for the bacteria in the biofilm....

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

    Directory of Open Access Journals (Sweden)

    Jennifer Soundy

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

  16. Pharmacokinetics/pharmacodynamics of colistin and imipenem on mucoid and nonmucoid Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Hengzhuang, Wang; Wu, Hong; Ciofu, Oana

    2011-01-01

    The time course of activity of colistin and imipenem against mucoid and nonmucoid Pseudomonas aeruginosa growing in a biofilm showed that compared with those for planktonic bacteria, the kinetics of colistin and imipenem retained the concentration- and time-dependent killing, respectively...

  17. N-acylhomoserine-lactone-mediated communication between Pseudomonas aeruginosa and Burkholderia cepacia in mixed biofilms

    DEFF Research Database (Denmark)

    Riedel, K.; Hentzer, Morten; Geisenberger, O.

    2001-01-01

    Pseudomonas aeruginosa and Burkholderia cepacia are capable of forming mixed biofilms in the lungs of cystic fibrosis patients. Both bacteria employ quorum-sensing systems, which rely on N-acylhomoserine lactone (AHL) signal molecules, to co- ordinate expression of virulence factors with the form...

  18. N-acylhomoserine-lactone-mediated communication between Pseudomonas aeruginosa and Burkholderia cepacia in mixed biofilms

    DEFF Research Database (Denmark)

    Riedel, K; Hentzer, Morten; Geisenberger, O

    2001-01-01

    Pseudomonas aeruginosa and Burkholderia cepacia are capable of forming mixed biofilms in the lungs of cystic fibrosis patients. Both bacteria employ quorum-sensing systems, which rely on N-acylhomoserine lactone (AHL) signal molecules, to co-ordinate expression of virulence factors with the forma...

  19. In-Vivo Expression Profiling of Pseudomonas aeruginosa Infections Reveals Niche-Specific and Strain-Independent Transcriptional Programs

    NARCIS (Netherlands)

    Bielecki, P.; Puchalka, J.; Wos-Oxley, M.L.; Martins Dos Santos, V.A.P.

    2011-01-01

    Pseudomonas aeruginosa is a threatening, opportunistic pathogen causing disease in immunocompromised individuals. The hallmark of P. aeruginosa virulence is its multi-factorial and combinatorial nature. It renders such bacteria infectious for many organisms and it is often resistant to antibiotics.

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

    OpenAIRE

    Faiqah Umar

    2015-01-01

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

  1. [Pseudomonas genus bacteria on weeds].

    Science.gov (United States)

    Gvozdiak, R I; Iakovleva, L M; Pasichnik, L A; Shcherbina, T N; Ogorodnik, L E

    2005-01-01

    It has been shown in the work that the weeds (couch-grass and ryegrass) may be affected by bacterial diseases in natural conditions, Pseudomonas genus bacteria being their agents. The isolated bacteria are highly-aggressive in respect of the host-plant and a wide range of cultivated plants: wheat, rye, oats, barley, apple-tree and pear-tree. In contrast to highly aggressive bacteria isolated from the affected weeds, bacteria-epi phytes isolated from formally healthy plants (common amaranth, orache, flat-leaved spurge, field sow thistle, matricary, common coltsfoot, narrow-leaved vetch) and identified as P. syringae pv. coronafaciens, were characterized by weak aggression. A wide range of ecological niches of bacteria evidently promote their revival and distribution everywhere in nature.

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

    African Journals Online (AJOL)

    DR. AMINU

    2009-05-30

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

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

    African Journals Online (AJOL)

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

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

    OpenAIRE

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

    2002-01-01

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

  5. Recent advances in understanding Pseudomonas aeruginosa as a pathogen

    Science.gov (United States)

    Klockgether, Jens; Tümmler, Burkhard

    2017-01-01

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

  6. A Novel Antimicrobial Endolysin, LysPA26, againstPseudomonas aeruginosa.

    Science.gov (United States)

    Guo, Mingquan; Feng, Chunyan; Ren, Jie; Zhuang, Xuran; Zhang, Yan; Zhu, Yongzhang; Dong, Ke; He, Ping; Guo, Xiaokui; Qin, Jinhong

    2017-01-01

    The global increase in multidrug resistant (MDR) bacteria has led to phage therapy being refocused upon. A novel endolysin, LysPA26, containing a lysozyme-like domain, was screened against Pseudomonas aeruginosa in this study. It had activity against MDR P. aeruginosa without pretreatment with an outer-membrane permeabilizer. LysPA26 could kill up to 4 log units P. aeruginosa in 30 min. In addition, temperature and pH effect assays revealed that LysPA26 had good stability over a broad range of pH and temperatures. Moreover, LysPA26 could kill other Gram-negative bacteria, such as Klebsiella pneumonia, Acinetobacter baumannii and Escherichia coli , but not Gram-positive bacteria. Furthermore, LysPA26 could eliminate P. aeruginosa in biofilm formation. Our current results show that LysPA26 is a new and promising antimicrobial agent for the combat of Gram-negative pathogens.

  7. Pseudomonas aeruginosa promotes Escherichia coli biofilm formation in nutrient-limited medium.

    Directory of Open Access Journals (Sweden)

    Alessandro Culotti

    Full Text Available Biofilms have been implicated as an important reservoir for pathogens and commensal enteric bacteria such as Escherichia coli in natural and engineered water systems. However, the processes that regulate the survival of E. coli in aquatic biofilms have not been thoroughly studied. We examined the effects of hydrodynamic shear and nutrient concentrations on E. coli colonization of pre-established Pseudomonas aeruginosa biofilms, co-inoculation of E. coli and P. aeruginosa biofilms, and P. aeruginosa colonization of pre-established E. coli biofilms. In nutritionally-limited R2A medium, E. coli dominated biofilms when co-inoculated with P. aeruginosa, and successfully colonized and overgrew pre-established P. aeruginosa biofilms. In more enriched media, P. aeruginosa formed larger clusters, but E. coli still extensively overgrew and colonized the interior of P. aeruginosa clusters. In mono-culture, E. coli formed sparse and discontinuous biofilms. After P. aeruginosa was introduced to these biofilms, E. coli growth increased substantially, resulting in patterns of biofilm colonization similar to those observed under other sequences of organism introduction, i.e., E. coli overgrew P. aeruginosa and colonized the interior of P. aeruginosa clusters. These results demonstrate that E. coli not only persists in aquatic biofilms under depleted nutritional conditions, but interactions with P. aeruginosa can greatly increase E. coli growth in biofilms under these experimental conditions.

  8. Surface Sensing for Biofilm Formation in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Chien-Yi Chang

    2018-01-01

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

  9. Effect of methylglyoxal on multidrug-resistant Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Katsuhiko eHayashi

    2014-04-01

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

  10. Whole genome sequence of Pseudomonas aeruginosa F9676, an antagonistic bacterium isolated from rice seed.

    Science.gov (United States)

    Shi, Zhenyuan; Ren, Deyong; Hu, Shikai; Hu, Xingming; Wu, Liwen; Lin, Haiyan; Hu, Jiang; Zhang, Guangheng; Guo, Longbiao

    2015-10-10

    Pseudomonas aeruginosa is a group of bacteria, which can be isolated from diverse ecological niches. P. aeruginosa strain F9676 was first isolated from a rice seed sample in 2003. It showed strong antagonism against several plant pathogens. In this study, whole genome sequencing was carried out. The total genome size of F9676 is 6368,008bp with 5586 coding genes (CDS), 67 tRNAs and 3 rRNAs. The genome sequence of F9676 may shed a light on antagonism P. aeruginosa. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Garlic blocks quorum sensing and promotes rapid clearing of pulmonary Pseudomonas aeruginosa infections

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, Peter Østrup; Rasmussen, Thomas B

    2005-01-01

    The opportunistic human pathogen Pseudomonas aeruginosa is the predominant micro-organism of chronic lung infections in cystic fibrosis patients. P. aeruginosa colonizes the lungs by forming biofilm microcolonies throughout the lung. Quorum sensing (QS) renders the biofilm bacteria highly tolerant......-treated biofilm. Garlic extract was administered as treatment for a mouse pulmonary infection model. Mice were treated with garlic extract or placebo for 7 days, with the initial 2 days being prophylactic before P. aeruginosa was instilled in the left lung of the mice. Bacteriology, mortality, histopathology...... and phagocytosis by PMNs, as well as leading to an improved outcome of pulmonary infections....

  12. Ambroxol interferes with Pseudomonas aeruginosa quorum sensing.

    Science.gov (United States)

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

    2010-09-01

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

  13. Novel Targets for Treatment of Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Morten; Alhede, Maria; Bjarnsholt, Thomas

    2014-01-01

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

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

    NARCIS (Netherlands)

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

    2003-01-01

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

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

    DEFF Research Database (Denmark)

    Fluge, G; Ojeniyi, B; Høiby, N

    2001-01-01

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

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

    African Journals Online (AJOL)

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

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

    African Journals Online (AJOL)

    Jane

    2010-12-20

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

  18. Type VI Secretion System in Pseudomonas aeruginosa

    Science.gov (United States)

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

    2011-01-01

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

  19. Study on Antibiotic compounds from Pseudomonas aeruginosa NO4 Strain

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-05-15

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

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

    Science.gov (United States)

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

    2005-10-05

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

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

    Science.gov (United States)

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

    2000-01-01

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

  2. Bioadsorption characteristics of Pseudomonas aeruginosa PAOI

    Directory of Open Access Journals (Sweden)

    Kőnig-Péter Anikó

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Luyan Ma

    2009-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Susanne Häussler

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

  5. Toxicogenomic response of Pseudomonas aeruginosa to ortho-phenylphenol

    Directory of Open Access Journals (Sweden)

    Toghrol Freshteh

    2008-10-01

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

  6. Mechanical destruction of pseudomonas aeruginosa biofilms by ultrasound exposure

    Science.gov (United States)

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

    2012-10-01

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

  7. Experimental Pseudomonas aeruginosa mediated rhino sinusitis in mink

    DEFF Research Database (Denmark)

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

    2017-01-01

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

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

    NARCIS (Netherlands)

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

    2000-01-01

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

  9. N-acetylcysteine inhibit biofilms produced by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Liu Youning

    2010-05-01

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

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

    OpenAIRE

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

    2005-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  12. Detection of Tox A Gene in Pseudomonas aeruginosa Strains Isolated from Dairy Products Using PCR and Determining the Antibiotic Resistance Pattern

    Directory of Open Access Journals (Sweden)

    Faeze Zadsafar

    2017-08-01

    Conclusion: Due to high presence of Pseudomonas aeruginosa in raw milk and existence of antibiotic resistance genes in this bacterium, applying appropriate strategies for hygiene control in animal husbandries, is necessary to prevent the spread of bacteria.

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

    Science.gov (United States)

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

    2015-02-12

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

  14. Pseudomonas aeruginosa Diversification during Infection Development in Cystic Fibrosis Lungs—A Review

    Science.gov (United States)

    Sousa, Ana Margarida; Pereira, Maria Olívia

    2014-01-01

    Pseudomonas aeruginosa is the most prevalent pathogen of cystic fibrosis (CF) lung disease. Its long persistence in CF airways is associated with sophisticated mechanisms of adaptation, including biofilm formation, resistance to antibiotics, hypermutability and customized pathogenicity in which virulence factors are expressed according the infection stage. CF adaptation is triggered by high selective pressure of inflamed CF lungs and by antibiotic treatments. Bacteria undergo genetic, phenotypic, and physiological variations that are fastened by the repeating interplay of mutation and selection. During CF infection development, P. aeruginosa gradually shifts from an acute virulent pathogen of early infection to a host-adapted pathogen of chronic infection. This paper reviews the most common changes undergone by P. aeruginosa at each stage of infection development in CF lungs. The comprehensive understanding of the adaptation process of P. aeruginosa may help to design more effective antimicrobial treatments and to identify new targets for future drugs to prevent the progression of infection to chronic stages. PMID:25438018

  15. A commensal streptococcus hijacks a Pseudomonas aeruginosa exopolysaccharide to promote biofilm formation.

    Directory of Open Access Journals (Sweden)

    Jessica A Scoffield

    2017-04-01

    Full Text Available Pseudomonas aeruginosa causes devastating chronic pulmonary infections in cystic fibrosis (CF patients. Although the CF airway is inhabited by diverse species of microorganisms interlaced within a biofilm, many studies focus on the sole contribution of P. aeruginosa pathogenesis in CF morbidity. More recently, oral commensal streptococci have been identified as cohabitants of the CF lung, but few studies have explored the role these bacteria play within the CF biofilm. We examined the interaction between P. aeruginosa and oral commensal streptococci within a dual species biofilm. Here we report that the CF P. aeruginosa isolate, FRD1, enhances biofilm formation and colonization of Drosophila melanogaster by the oral commensal Streptococcus parasanguinis. Moreover, production of the P. aeruginosa exopolysaccharide, alginate, is required for the promotion of S. parasanguinis biofilm formation and colonization. However, P. aeruginosa is not promoted in the dual species biofilm. Furthermore, we show that the streptococcal adhesin, BapA1, mediates alginate-dependent enhancement of the S. parasanguinis biofilm in vitro, and BapA1 along with another adhesin, Fap1, are required for the in vivo colonization of S. parasanguinis in the presence of FRD1. Taken together, our study highlights a new association between streptococcal adhesins and P. aeruginosa alginate, and reveals a mechanism by which S. parasanguinis potentially colonizes the CF lung and interferes with the pathogenesis of P. aeruginosa.

  16. Autoinducer-2 Facilitates Pseudomonas aeruginosa PAO1 Pathogenicity in Vitro and in Vivo

    Directory of Open Access Journals (Sweden)

    Hongdong Li

    2017-10-01

    Full Text Available Bacterial communication systems, such as quorum sensing (QS, have provided new insights of alternative approaches in antimicrobial treatment. We recently reported that one QS signal, named as autoinducer-2 (AI-2, can affect the behaviors of Pseudomonas aeruginosa PAO1 in a dose-dependent manner. In this study, we aimed to investigate the effects of AI-2 on P. aeruginosa PAO1 biofilm formation and virulence factors production in vitro, and in vivo using a pulmonary infection mouse model. Exogenous AI-2 resulted in increased biofilms architecture, the number of viable cells, and the yield of pyocyanin and elastase virulence factors in wild type P. aeruginosa PAO1. However, no such effect was observed in P. aeruginosa lasR rhlR mutant strain. In vivo, the use of AI-2 significantly increased the mortality, lung bacterial count and histological lung damage of mice with acute P. aeruginosa PAO1 infection. Our data suggest that AI-2 promotes the formation of P. aeruginosa PAO1 biofilms and the production of virulence factors by interfering with P. aeruginosa QS systems, resulting in decreased host survival. AI-2 may be a therapeutic target for the clinical treatment of a co-infection of P. aeruginosa and AI-2 producing bacteria.

  17. A commensal streptococcus hijacks a Pseudomonas aeruginosa exopolysaccharide to promote biofilm formation.

    Science.gov (United States)

    Scoffield, Jessica A; Duan, Dingyu; Zhu, Fan; Wu, Hui

    2017-04-01

    Pseudomonas aeruginosa causes devastating chronic pulmonary infections in cystic fibrosis (CF) patients. Although the CF airway is inhabited by diverse species of microorganisms interlaced within a biofilm, many studies focus on the sole contribution of P. aeruginosa pathogenesis in CF morbidity. More recently, oral commensal streptococci have been identified as cohabitants of the CF lung, but few studies have explored the role these bacteria play within the CF biofilm. We examined the interaction between P. aeruginosa and oral commensal streptococci within a dual species biofilm. Here we report that the CF P. aeruginosa isolate, FRD1, enhances biofilm formation and colonization of Drosophila melanogaster by the oral commensal Streptococcus parasanguinis. Moreover, production of the P. aeruginosa exopolysaccharide, alginate, is required for the promotion of S. parasanguinis biofilm formation and colonization. However, P. aeruginosa is not promoted in the dual species biofilm. Furthermore, we show that the streptococcal adhesin, BapA1, mediates alginate-dependent enhancement of the S. parasanguinis biofilm in vitro, and BapA1 along with another adhesin, Fap1, are required for the in vivo colonization of S. parasanguinis in the presence of FRD1. Taken together, our study highlights a new association between streptococcal adhesins and P. aeruginosa alginate, and reveals a mechanism by which S. parasanguinis potentially colonizes the CF lung and interferes with the pathogenesis of P. aeruginosa.

  18. Pseudomonas aeruginosa d-Arabinofuranose Biosynthetic Pathway and Its Role in Type IV Pilus Assembly*

    OpenAIRE

    Harvey, Hanjeong; Kus, Julianne V.; Tessier, Luc; Kelly, John; Burrows, Lori L.

    2011-01-01

    Pseudomonas aeruginosa strains PA7 and Pa5196 glycosylate their type IVa pilins with α1,5-linked d-arabinofuranose (d-Araf), a rare sugar configuration identical to that found in cell wall polymers of the Corynebacterineae. Despite this chemical identity, the pathway for biosynthesis of α1,5-d-Araf in Gram-negative bacteria is unknown. Bioinformatics analyses pointed to a cluster of seven P. aeruginosa genes, including homologues of the Mycobacterium tuberculosis genes Rv3806c, Rv3790, and Rv...

  19. Aspergillus triggers phenazine production in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

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

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

  20. Suppression of Aspergillus by Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

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

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

  1. Extended-spectrum beta-lactamase-producing Pseudomonas aeruginosa in camel in Egypt: potential human hazard.

    Science.gov (United States)

    Elhariri, Mahmoud; Hamza, Dalia; Elhelw, Rehab; Dorgham, Sohad M

    2017-03-31

    The rapid increase of extended-spectrum beta-lactamase (ESBL) producing bacteria are a potential health hazard. Development of antimicrobial resistance in animal pathogens has serious implications for human health, especially when such strains could be transmitted to human. In this study, the antimicrobial resistance due to ESBL producing Pseudomonas aeruginosa in the camel meat was investigated. In this study meat samples from 200 healthy camels at two major abattoirs in Egypt (Cairo and Giza) were collected. Following culture on cetrimide agar, suspected P. aeruginosa colonies were confirmed with a Vitek 2 system (bioMe´rieux). P. aeruginosa isolates were phenotypically identified as ESBL by double disk synergy test. Additionally antimicrobial susceptibility testing of ESBL producing P. aeruginosa isolates were done against 11 antimicrobial drugs and carried out by disk diffusion method. The ESBL genotypes were determined by polymerase chain reaction according to the presence of the bla PER-1, bla CTX-M, bla SHV, and bla TEM. Pseudomonas aeruginosa was isolated from 45 camel meat sample (22.5%). The total percentage of ESBL producing P. aeruginosa was 45% (21/45) from camel meat isolates. Antibiogram results revealed the highest resistance was for c, ceftriaxone and rifampicin followed by cefepime and aztreonam. The prevalence rates of β-lactamase genes were recorded (bla PER-1 28.5%, bla CTX-M 38%, bla SHV 33.3% and bla TEM 23.8%). This study illustrates the presence of high rates of ESBL-P. aeruginosa in camels that represents an increasing alarming for the risk of transmission to human and opens the door for current and future antibiotics therapy failure. Livestock associated ESBL-P. aeruginosa is a growing disaster, therefore, attention has to be fully given to livestock associated ESBL-bacteria which try to find its way to human beings.

  2. Pseudomonas aeruginosa Diversification during Infection Development in Cystic Fibrosis Lungs—A Review

    OpenAIRE

    Ana Margarida Sousa; Maria Olívia Pereira

    2014-01-01

    Pseudomonas aeruginosa is the most prevalent pathogen of cystic fibrosis (CF) lung disease. Its long persistence in CF airways is associated with sophisticated mechanisms of adaptation, including biofilm formation, resistance to antibiotics, hypermutability and customized pathogenicity in which virulence factors are expressed according the infection stage. CF adaptation is triggered by high selective pressure of inflamed CF lungs and by antibiotic treatments. Bacteria undergo genetic, phenoty...

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

    Directory of Open Access Journals (Sweden)

    Zeynab Golshani

    2012-11-01

    Full Text Available Please cite this article as: Golshani Z, Ahadi AM, Sharifzadeh A. Antimicrobial Susceptibility Pattern of Pseudomonas aeruginosa Isolated from Patients Referring to Hospitals. Arch Hyg Sci 2012;1(2:48-53. Abstract: Background & Aims of the Study: The aim of this study was to detect and survey the antibiotic resistance pattern of Pseudomonas (P. aeruginosa isolated from patients in Isfahan (located in central Iran hospitals. Materials & Methods : A Total of 50 clinical isolates of P. aeruginosa were collected from urine, wound, trachea, ear swab, and pus, and then were confirmed by standard tests. Antibiotic susceptibility was determined by the Kirby-Bauer disc diffusion method. Susceptibility data were compared by chi-square test using SPSS version 15. Results: Among the isolated strains, resistance to oxacillin was seen in 100%, ceftriaxone in 76%, amikacin in 70%, ceftazidime in 68%, cefepime in 68%, tobramycin in 62%, gentamicin in 60%, ciprofloxacin in 58%, and imipenem in 58% of the isolates. Conclusions: Comparison of the results showed that, patterns of antibiotic resistance are different from one hospital to another in various areas. Therefore, it is suggested that such studies should be performed in different hospitals. Also, prescribing correct medications is essential to prevent further increases in resistant bacteria. References: 1. Pagani L, Mantengoli E, Migliavacca R, Nucleo E, Pollini S, Spalla M, et al. Multifocal Detection of Multidrug-Resistant Pseudomonas aeruginosa Producing the PER-1 Extended- Spectrum β-Lactamase in Northern Italy. J Clin Microbiol 2004;42(6:2523–9. 2. Ling TKW, Xiong J, Yu Y, Lee CC, Ye H, Hawkey PM, et al. Multicenter Antimicrobial Susceptibility Survey of Gram-Negative Bacteria Isolated from Patients with Community-Acquired Infections in the People's Republic of China. Antimicrob Agents Chemother 2006;50(1:374–8. 3. Gupta V, Datta P, Agnihotri N, Chander J. Comparative in vitro Activities of Seven

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

    OpenAIRE

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

    2001-01-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

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

    African Journals Online (AJOL)

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

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

    NARCIS (Netherlands)

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

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

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

    DEFF Research Database (Denmark)

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

    1991-01-01

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

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

    NARCIS (Netherlands)

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

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

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

    African Journals Online (AJOL)

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

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

    African Journals Online (AJOL)

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

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

    African Journals Online (AJOL)

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

  13. Rhamnolipid stimulates uptake of hydrophobic compounds by Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Noordman, WH; Janssen, DB

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

  14. Isolation and characterization of gallium resistant Pseudomonas aeruginosa mutants

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    Czech Academy of Sciences Publication Activity Database

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

    2016-01-01

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

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

    African Journals Online (AJOL)

    Administrator

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

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

    NARCIS (Netherlands)

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

    2001-01-01

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

  18. Mitophagy confers resistance to siderophore-mediated killing by Pseudomonas aeruginosa.

    Science.gov (United States)

    Kirienko, Natalia V; Ausubel, Frederick M; Ruvkun, Gary

    2015-02-10

    In the arms race of bacterial pathogenesis, bacteria produce an array of toxins and virulence factors that disrupt core host processes. Hosts mitigate the ensuing damage by responding with immune countermeasures. The iron-binding siderophore pyoverdin is a key virulence mediator of the human pathogen Pseudomonas aeruginosa, but its pathogenic mechanism has not been established. Here we demonstrate that pyoverdin enters Caenorhabditis elegans and that it is sufficient to mediate host killing. Moreover, we show that iron chelation disrupts mitochondrial homeostasis and triggers mitophagy both in C. elegans and mammalian cells. Finally, we show that mitophagy provides protection both against the extracellular pathogen P. aeruginosa and to treatment with a xenobiotic chelator, phenanthroline, in C. elegans. Although autophagic machinery has been shown to target intracellular bacteria for degradation (a process known as xenophagy), our report establishes a role for authentic mitochondrial autophagy in the innate immune defense against P. aeruginosa.

  19. Gallium-Protoporphyrin IX Inhibits Pseudomonas aeruginosa Growth by Targeting Cytochromes.

    Science.gov (United States)

    Hijazi, Sarah; Visca, Paolo; Frangipani, Emanuela

    2017-01-01

    Pseudomonas aeruginosa is a challenging pathogen due to both innate and acquired resistance to antibiotics. It is capable of causing a variety of infections, including chronic lung infection in cystic fibrosis (CF) patients. Given the importance of iron in bacterial physiology and pathogenicity, iron-uptake and metabolism have become attractive targets for the development of new antibacterial compounds. P. aeruginosa can acquire iron from a variety of sources to fulfill its nutritional requirements both in the environment and in the infected host. The adaptation of P. aeruginosa to heme iron acquisition in the CF lung makes heme utilization pathways a promising target for the development of new anti-Pseudomonas drugs. Gallium [Ga(III)] is an iron mimetic metal which inhibits P. aeruginosa growth by interfering with iron-dependent metabolism. The Ga(III) complex of the heme precursor protoporphyrin IX (GaPPIX) showed enhanced antibacterial activity against several bacterial species, although no inhibitory effect has been reported on P. aeruginosa. Here, we demonstrate that GaPPIX is indeed capable of inhibiting the growth of clinical P. aeruginosa strains under iron-deplete conditions, as those encountered by bacteria during infection, and that GaPPIX inhibition is reversed by iron. Using P. aeruginosa PAO1 as model organism, we show that GaPPIX enters cells through both the heme-uptake systems has and phu, primarily via the PhuR receptor which plays a crucial role in P. aeruginosa adaptation to the CF lung. We also demonstrate that intracellular GaPPIX inhibits the aerobic growth of P. aeruginosa by targeting cytochromes, thus interfering with cellular respiration.

  20. Pseudomonas aeruginosa Microcolonies in Coronary Thrombi from Patients with ST-Segment Elevation Myocardial Infarction.

    Directory of Open Access Journals (Sweden)

    Gorm Mørk Hansen

    Full Text Available Chronic infection is associated with an increased risk of atherothrombotic disease and direct bacterial infection of arteries has been suggested to contribute to the development of unstable atherosclerotic plaques. In this study, we examined coronary thrombi obtained in vivo from patients with ST-segment elevation myocardial infarction (STEMI for the presence of bacterial DNA and bacteria. Aspirated coronary thrombi from 22 patients with STEMI were collected during primary percutaneous coronary intervention and arterial blood control samples were drawn from radial or femoral artery sheaths. Analyses were performed using 16S polymerase chain reaction and with next-generation sequencing to determine bacterial taxonomic classification. In selected thrombi with the highest relative abundance of Pseudomonas aeruginosa DNA, peptide nucleic acid fluorescence in situ hybridization (PNA-FISH with universal and species specific probes was performed to visualize bacteria within thrombi. From the taxonomic analysis we identified a total of 55 different bacterial species. DNA from Pseudomonas aeruginosa represented the only species that was significantly associated with either thrombi or blood and was >30 times more abundant in thrombi than in arterial blood (p<0.0001. Whole and intact bacteria present as biofilm microcolonies were detected in selected thrombi using universal and P. aeruginosa-specific PNA-FISH probes. P. aeruginosa and vascular biofilm infection in culprit lesions may play a role in STEMI, but causal relationships remain to be determined.

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

    Science.gov (United States)

    Adegboye, Temitope Azeezat

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

  2. Pseudomonas aeruginosa multiresistente em unidade de cuidados intensivos: desafios que procedem? Pseudomonas aeruginosa multiresistente en una unidad de cuidados intensivos: desafíos que proceden? Multi-resistant pseudomonas aeruginosa among patients from an intensive care unit: persistent challenge?

    Directory of Open Access Journals (Sweden)

    Maria Verônica Guilherme Ferrareze

    2007-03-01

    Full Text Available OBJETIVOS: Avaliar a ocorrência de infecção hospitalar por Pseudomonas aeruginosa multiresistente em pacientes hospitalizados em uma unidade de cuidados intensivos. MÉTODO: estudo retrospectivo realizado de outubro de 2003 a setembro de 2004 em um hospital de emergências. RESULTADOS: Totalizou-se 68 portadores de bactérias multiresistentes sendo 10 (14,7% de P. aeruginosa. Destes, 8 pacientes eram do sexo masculino, as médias de idade e de internação foram respectivamente de 57 anos a média de idade, 43,7 a média de dias de internação e 7 pacientes morreram. Isolaram-se 8 cepas no sangue, cinco na urina, duas em cateteres venosos e uma no líquor, das quais sete sensíveis somente a polimixina e três ao imipenem. CONCLUSÃO: O perfil microbiológico deve ser avaliado periodicamente visto que é específico de uma unidade ou instituição, e demanda ações correlatas.OBJETIVOS: Evaluar la ocurrencia de infección hospitalaria por Pseudomonas aeruginosa multiresistente en pacientes hospitalizados en una unidad de cuidados intensivos. MÉTODO: estudio retrospectivo realizado de octubre del 2003 a setiembre del 2004 en un hospital de emergencias. RESULTADOS: Se tuvo un total de 68 portadores de bacterias multiresistentes de las cuales 10 (14,7% de P. aeruginosa. De éstos, 8 pacientes eran del sexo masculino, los promedios de edad y de internamiento fueron respectivamente de 57 años y 43,7 de días de internamiento y 7 pacientes murieron. Se aislaron 8 cepas en la sangre, cinco en la orina, dos en catéteres venosos y una en el licor, de ellas siete eran sensibles sólo a la polimixina y tres al imipenem. CONCLUSIÓN: El perfil microbiológico debe ser evaluado periódicamente dado que es específico de una unidad o institución, y demanda acciones correlatas.OBJECTIVES: To evaluate the occurrence of multi-resistant Pseudomonas Aeruginosa infection among patients from an Intensive Care Unit. METHODS: This retrospective study was

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

    DEFF Research Database (Denmark)

    Farver, Ole; Brunori, Maurizio; Cutruzzolà, Francesca

    2009-01-01

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

  4. Pseudomonas aeruginosa-associated Diarrheal Diseases in Children.

    Science.gov (United States)

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

    2017-12-01

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

  5. The Multiple Signaling Systems Regulating Virulence in Pseudomonas aeruginosa

    Science.gov (United States)

    Nadal Jimenez, Pol; Koch, Gudrun; Thompson, Jessica A.; Xavier, Karina B.; Cool, Robbert H.

    2012-01-01

    Summary: Cell-to-cell communication is a major process that allows bacteria to sense and coordinately react to the fluctuating conditions of the surrounding environment. In several pathogens, this process triggers the production of virulence factors and/or a switch in bacterial lifestyle that is a major determining factor in the outcome and severity of the infection. Understanding how bacteria control these signaling systems is crucial to the development of novel antimicrobial agents capable of reducing virulence while allowing the immune system of the host to clear bacterial infection, an approach likely to reduce the selective pressures for development of resistance. We provide here an up-to-date overview of the molecular basis and physiological implications of cell-to-cell signaling systems in Gram-negative bacteria, focusing on the well-studied bacterium Pseudomonas aeruginosa. All of the known cell-to-cell signaling systems in this bacterium are described, from the most-studied systems, i.e., N-acyl homoserine lactones (AHLs), the 4-quinolones, the global activator of antibiotic and cyanide synthesis (GAC), the cyclic di-GMP (c-di-GMP) and cyclic AMP (cAMP) systems, and the alarmones guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp), to less-well-studied signaling molecules, including diketopiperazines, fatty acids (diffusible signal factor [DSF]-like factors), pyoverdine, and pyocyanin. This overview clearly illustrates that bacterial communication is far more complex than initially thought and delivers a clear distinction between signals that are quorum sensing dependent and those relying on alternative factors for their production. PMID:22390972

  6. Acquisition and Role of Molybdate in Pseudomonas aeruginosa

    Science.gov (United States)

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

    2014-01-01

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

  7. [Cervical lymphoadenopathy due to Pseudomonas aeruginosa following mesotherapy].

    Science.gov (United States)

    Shaladi, Ali Muftah; Crestani, Francesco; Bocchi, Anna; Saltari, Maria Rita; Piva, Bruno; Tartari, Stefano

    2009-09-01

    Mesotherapy is a treatment method devised for controlling several diseases by means of subcutaneous microinjections given at or around the affected areas at short time intervals. It is used to treat a variety of medical conditions, amongst which all orthopaedic diseases and rheumatic pain. Mesotherapy is especially indicated for neck pain. The mechanism of action is twofold: a pharmacological effect due to the drug administered, and a reflexogenic effect, the skin containing many nerve endings that are sensitive to the mechanical action of the needle. Although this therapy is safe, like any other medical intervention it cannot be considered free of complications that may occur, such as allergies, haematomas, bruising, wheals, granulomas and telangiectasias. Infective complications are also possible, due to pathogenic bacteria that are inoculated through contamination of products, of the materials used for the procedure or even from germs on the skin. We present the case of a patient who had cervical lymphadenopathy due to Pseudomonas aeruginosa after mesotherapy treatment for neck pain.

  8. Ginger Extract Inhibits Biofilm Formation by Pseudomonas aeruginosa PA14

    Science.gov (United States)

    Kim, Han-Shin; Park, Hee-Deung

    2013-01-01

    Bacterial biofilm formation can cause serious problems in clinical and industrial settings, which drives the development or screening of biofilm inhibitors. Some biofilm inhibitors have been screened from natural products or modified from natural compounds. Ginger has been used as a medicinal herb to treat infectious diseases for thousands of years, which leads to the hypothesis that it may contain chemicals inhibiting biofilm formation. To test this hypothesis, we evaluated ginger’s ability to inhibit Pseudomonas aeruginosa PA14 biofilm formation. A static biofilm assay demonstrated that biofilm development was reduced by 39–56% when ginger extract was added to the culture. In addition, various phenotypes were altered after ginger addition of PA14. Ginger extract decreased production of extracellular polymeric substances. This finding was confirmed by chemical analysis and confocal laser scanning microscopy. Furthermore, ginger extract formed noticeably less rugose colonies on agar plates containing Congo red and facilitated swarming motility on soft agar plates. The inhibition of biofilm formation and the altered phenotypes appear to be linked to a reduced level of a second messenger, bis-(3′-5′)-cyclic dimeric guanosine monophosphate. Importantly, ginger extract inhibited biofilm formation in both Gram-positive and Gram-negative bacteria. Also, surface biofilm cells formed with ginger extract detached more easily with surfactant than did those without ginger extract. Taken together, these findings provide a foundation for the possible discovery of a broad spectrum biofilm inhibitor. PMID:24086697

  9. Novel polymeric nanoparticles targeting the lipopolysaccharides of Pseudomonas aeruginosa.

    Science.gov (United States)

    Long, Y; Li, Z; Bi, Q; Deng, C; Chen, Z; Bhattachayya, S; Li, C

    2016-04-11

    Considering outburst of various infectious diseases globally, nanoparticle assisted targeted drug delivery has emerged as a promising strategy that can enhance the therapeutic efficacy and minimize the undesirable side effects of an antimicrobial agents. Molecular imprinting is a newly developed strategy that can synthesize a drug carrier with highly stable ligand-like 'cavity', may serve as a new platform of ligand-free targeted drug delivery systems. In this study, we use the amphiphilic lipopolysaccharides, derived from Pseudomonas aeruginosa as imprinting template and obtained an evenly distributed sub-40 nm polymeric nanoparticles by using inverse emulsion method. These molecularly imprinted nanoparticles (MIPNPs) showed specific binding to the lipopolysaccharide as determined by fluorescence polarization and microscale thermophoresis. MIPNPs showed selective recognition of target bacteria as detected by flow cytometry. Additionally, MIPNPs exhibited the in vivo targeting capabilities in both the keratitis model and meningitis model. Moreover, the photosensitizer methylene blue-loaded MIPNPs presented significantly strong inhibition of bacterial Growth, compared to non-imprinted controls for in vitro model of the photodynamic therapy. Our study shows an attempt to design a magic bullet by molecular imprinting that may provide a novel approach to generate synthetic carrier for targeting pathogen and treatment for a variety of infectious human diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2016-03-01

    Microbial biofilm are communities of surface-adhered cells enclosed in a matrix of extracellular polymeric substances. Extensive use of antibiotics to treat biofilm associated infections has led to the emergence of multiple drug resistant strains. Pseudomonas aeruginosa is recognised as a model biofilm forming pathogenic bacterium. Vitexin, a polyphenolic group of phytochemical with antimicrobial property, has been studied for its antibiofilm potential against Pseudomonas aeruginosa in combination with azithromycin and gentamicin. Vitexin shows minimum inhibitory concentration (MIC) at 260 μg/ml. It’s antibiofilm activity was evaluated by safranin staining, protein extraction, microscopy methods, quantification of EPS and in vivo models using several sub-MIC doses. Various quorum sensing (QS) mediated phenomenon such as swarming motility, azocasein degrading protease activity, pyoverdin and pyocyanin production, LasA and LasB activity of the bacteria were also evaluated. Results showed marked attenuation in biofilm formation and QS mediated phenotype of Pseudomonas aeruginosa in presence of 110 μg/ml vitexin in combination with azithromycin and gentamicin separately. Molecular docking of vitexin with QS associated LuxR, LasA, LasI and motility related proteins showed high and reasonable binding affinity respectively. The study explores the antibiofilm potential of vitexin against P. aeruginosa which can be used as a new antibiofilm agent against microbial biofilm associated pathogenesis.

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

    Directory of Open Access Journals (Sweden)

    Pierre eCornelis

    2013-11-01

    Full Text Available Pseudomonas aeruginosa is a Gram-negative -Proteobacterium which is known for its capacity to colonize various niches, including some invertebrate and vertebrate hosts, making it one of the most frequent bacteria causing opportunistic infections. P. aeruginosa is able to cause acute as well as chronic infections and it uses different colonization and virulence factors to do so. Infections range from septicemia, urinary infections, burn wound colonization, and chronic colonization of the lungs of cystic fibrosis patients. Like the vast majority of organisms, P. aeruginosa needs iron to sustain growth. P. aeruginosa utilizes different strategies to take up iron, depending on the type of infection it causes. Two siderophores are produced by this bacterium, pyoverdine and pyochelin, characterized by high and low affinities for iron respectively. P. aeruginosa is also able to utilize different siderophores from other microorganisms (siderophore piracy. It can also take up heme from hemoproteins via two different systems. Under microaerobic or anaerobic conditions, P. aeruginosa is also able to take up ferrous iron via its Feo system using redox-cycling phenazines. Depending on the type of infection, P. aeruginosa can therefore adapt by switching from one iron uptake system to another as we will describe in this short review.

  12. Pseudomonas aeruginosa disrupts Caenorhabditis elegans iron homeostasis, causing a hypoxic response and death.

    Science.gov (United States)

    Kirienko, Natalia V; Kirienko, Daniel R; Larkins-Ford, Jonah; Wählby, Carolina; Ruvkun, Gary; Ausubel, Frederick M

    2013-04-17

    The opportunistic pathogen Pseudomonas aeruginosa causes serious human infections, but effective treatments and the mechanisms mediating pathogenesis remain elusive. Caenorhabditis elegans shares innate immune pathways with humans, making it invaluable to investigate infection. To determine how P. aeruginosa disrupts host biology, we studied how P. aeruginosa kills C. elegans in a liquid-based pathogenesis model. We found that P. aeruginosa-mediated killing does not require quorum-sensing pathways or host colonization. A chemical genetic screen revealed that iron chelators alleviate P. aeruginosa-mediated killing. Consistent with a role for iron in P. aeruginosa pathogenesis, the bacterial siderophore pyoverdin was required for virulence and was sufficient to induce a hypoxic response and death in the absence of bacteria. Loss of the C. elegans hypoxia-inducing factor HIF-1, which regulates iron homeostasis, exacerbated P. aeruginosa pathogenesis, further linking hypoxia and killing. As pyoverdin is indispensable for virulence in mice, pyoverdin-mediated hypoxia is likely to be relevant in human pathogenesis. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Diverse effects of Galleria mellonella infection with entomopathogenic and clinical strains of Pseudomonas aeruginosa.

    Science.gov (United States)

    Andrejko, Mariola; Zdybicka-Barabas, Agnieszka; Cytryńska, Małgorzata

    2014-01-01

    In numerous studies, the greater wax moth Galleria mellonella has been exploited as an alternative model host for investigating virulence factors of different pathogenic bacteria. In the present paper, we provide evidence that G. mellonella constitutes a useful and convenient model for analysis of the pathogenicity of Pseudomonas aeruginosa clinical strains. In this in vivo study on the G. mellonella–P. aeruginosa interaction, a bidirectional analysis comprising evaluation of humoral immune response of the bacteria-infected larvae and determination of P. aeruginosa proteinases synthesized during the infection was performed. The effects of G. mellonella infection by two clinical strains (PA C124/9 and PA 02/18) and one entomopathogenic strain (ATCC 27853) cultured in a rich LB and minimal M9 medium, known to induce synthesis of different sets of extracellular proteinases, were evaluated. Both clinical isolates were able to establish infection in G. mellonella caterpillars after intrahemocelic injection. However, although the final effect of the larvae infection by each P. aeruginosa strain was their death within ca. 48 h, considerable strain and medium-dependent differences in the immune response of the insects were detected. The results indicated that G. mellonella larvae distinguished between the three P. aeruginosa strains, which was well reflected by the diverse humoral immune response. The significant differences concerned, among others, the level of phenoloxidase, lysozyme, and antibacterial activity in the hemolymph of the infected insects. An analysis of proteinases performed using specific activity tests, zymography and immunoblotting, revealed that elastase B and alkaline protease were synthesized by each P. aeruginosa strain during the infection. In contrast, a high level of elastase A activity was detected only in the larvae infected by the P. aeruginosa ATCC 27853 strain. It can be postulated that the three P. aeruginosa strains exploit different

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

    Science.gov (United States)

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

    2014-08-01

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

  15. Pseudomonas aeruginosa in premise plumbing of large buildings.

    Science.gov (United States)

    Bédard, Emilie; Prévost, Michèle; Déziel, Eric

    2016-12-01

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

  16. Interactions between Neutrophils and Pseudomonas aeruginosa in Cystic Fibrosis

    Science.gov (United States)

    Rada, Balázs

    2017-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Olga Zaborina

    2007-03-01

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

  18. The role of 2,4-dihydroxyquinoline (DHQ in Pseudomonas aeruginosa pathogenicity

    Directory of Open Access Journals (Sweden)

    Jordon D. Gruber

    2016-01-01

    Full Text Available Bacteria synchronize group behaviors using quorum sensing, which is advantageous during an infection to thwart immune cell attack and resist deleterious changes in the environment. In Pseudomonas aeruginosa, the Pseudomonas quinolone signal (Pqs quorum-sensing system is an important component of an interconnected intercellular communication network. Two alkylquinolones, 2-heptyl-4-quinolone (HHQ and 2-heptyl-3-hydroxy-4-quinolone (PQS, activate transcriptional regulator PqsR to promote the production of quinolone signals and virulence factors. Our work focused on the most abundant quinolone produced from the Pqs system, 2,4-dihydroxyquinoline (DHQ, which was shown previously to sustain pyocyanin production and antifungal activity of P. aeruginosa. However, little is known about how DHQ affects P. aeruginosa pathogenicity. Using C. elegans as a model for P. aeruginosa infection, we found pqs mutants only able to produce DHQ maintained virulence towards the nematodes similar to wild-type. In addition, DHQ-only producing mutants displayed increased colonization of C. elegans and virulence factor production compared to a quinolone-null strain. DHQ also bound to PqsR and activated the transcription of pqs operon. More importantly, high extracellular concentration of DHQ was maintained in both aerobic and anaerobic growth. High levels of DHQ were also detected in the sputum samples of cystic fibrosis patients. Taken together, our findings suggest DHQ may play an important role in sustaining P. aeruginosa pathogenicity under oxygen-limiting conditions.

  19. Impact of alginate-producing Pseudomonas aeruginosa on alveolar macrophage apoptotic cell clearance

    Science.gov (United States)

    Poirier, Christophe; Serban, Karina A.

    2014-01-01

    Pseudomonas aeruginosa infection is a hallmark of lung disease in cystic fibrosis. Acute infection with P. aeruginosa profoundly inhibits alveolar macrophage clearance of apoptotic cells (efferocytosis) via direct effect of virulence factors. During chronic infection, P. aeruginosa evades host defense by decreased virulence, which includes the production or, in the case of mucoidy, overproduction of alginate. The impact of alginate on innate immunity, in particular on macrophage clearance of apoptotic cells is not known. We hypothesized that P. aeruginosa strains that exhibit reduced virulence impair macrophage clearance of apoptotic cells and we investigated if the polysaccharide alginate produced by mucoid P. aeruginosa is sufficient to inhibit alveolar macrophage efferocytosis. Rat alveolar or human peripheral blood monocyte (THP-1)-derived macrophages cell lines were exposed in vitro to exogenous alginate or to wild type or alginate-overproducing mucoid P. aeruginosa prior to challenge with apoptotic human Jurkat T-lymphocytes. The importance of LPS contamination and that of structural integrity of alginate polymers was tested using alginate of different purities and alginate lyase, respectively. Alginate inhibited alveolar macrophage efferocytosis in a dose- and time-dependent manner. This effect was augmented but not exclusively attributed to lipopolysaccharide (LPS) present in alginates. Alginate-producing P. aeruginosa inhibited macrophage efferocytosis by more than 50%. Although alginate lyase did not significantly restore efferocytosis in the presence of exogenous alginate, it had a marked beneficial effect on efferocytosis of alveolar macrophages exposed to mucoid P. aeruginosa. Despite decreased virulence, mucoid P. aeruginosa may contribute to ongoing airway inflammation through significant inhibition of alveolar clearance of apoptotic cells and debris. The mechanism by which mucoid bacteria inhibit efferocytosis may involve alginate production and

  20. Silver Nanocomposite Biosynthesis: Antibacterial Activity against Multidrug-Resistant Strains of Pseudomonas aeruginosa and Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Klebson Silva Santos

    2016-09-01

    Full Text Available Bacterial resistance is an emerging public health issue that is disseminated worldwide. Silver nanocomposite can be an alternative strategy to avoid Gram-positive and Gram-negative bacteria growth, including multidrug-resistant strains. In the present study a silver nanocomposite was synthesized, using a new green chemistry process, by the addition of silver nitrate (1.10−3 mol·L−1 into a fermentative medium of Xanthomonas spp. to produce a xanthan gum polymer. Transmission electron microscopy (TEM was used to evaluate the shape and size of the silver nanoparticles obtained. The silver ions in the nanocomposite were quantified by flame atomic absorption spectrometry (FAAS. The antibacterial activity of the nanomaterial against Escherichia coli (ATCC 22652, Enterococcus faecalis (ATCC 29282, Pseudomonas aeruginosa (ATCC 27853 and Staphylococcus aureus (ATCC 25923 was carried out using 500 mg of silver nanocomposite. Pseudomonas aeruginosa and Acinetobacter baumannii multidrug-resistant strains, isolated from hospitalized patients were also included in the study. The biosynthesized silver nanocomposite showed spherical nanoparticles with sizes smaller than 10 nm; 1 g of nanocomposite contained 49.24 µg of silver. Multidrug-resistant strains of Pseudomonas aeruginosa and Acinetobacter baumannii, and the other Gram-positive and Gram-negative bacteria tested, were sensitive to the silver nanocomposite (10–12.9 mm of inhibition zone. The biosynthesized silver nanocomposite seems to be a promising antibacterial agent for different applications, namely biomedical devices or topical wound coatings.

  1. Antibacterial photodynamic therapy on Staphylococcus aureus and Pseudomonas aeruginosa in-vitro.

    Science.gov (United States)

    Thakuri, P S; Joshi, R; Basnet, S; Pandey, S; Taujale, S D; Mishra, N

    2011-12-01

    Photodynamic therapy (PDT) involves the use of drugs or dyes known as photosensitizers, and light source which induces cell death by the production of cytotoxic reactive oxygen species (ROS). This principle of cell death can be utilized to kill bacteria in vitro. We propose the use of blue light emitting diodes (LEDs) and Riboflavin as the light source and photosensitizer for in vitro killing of Staphylococcus aureus and Pseudomonas aeruginosa. Circularly arranged 65-blue LED array was designed as the light source to fit exactly over 7cm culture plate. Riboflavin having non-toxic properties and nucleic acid specificity was used as a photosensitizer. Clinical isolates of Staphylococcus aureus and Pseudomonas aeruginosa were used in our study. Effect of PDT on viability on these species of bacteria was compared with control samples that included: control untreated, control treated with light only and control treated with riboflavin only. Statistical analysis was done using one-way ANOVA test. PDT against Pseudomonas aeruginosa and Staphylococcus aureus was significantly (p blue LEDs and Riboflavin in PDT against these bacterial species has been successfully demonstrated in-vitro. Therefore, PDT has promising applications in the process of treating superficial wound infections.

  2. Quorum Sensing Protects Pseudomonas aeruginosa against Cheating by Other Species in a Laboratory Coculture Model.

    Science.gov (United States)

    Smalley, Nicole E; An, Dingding; Parsek, Matthew R; Chandler, Josephine R; Dandekar, Ajai A

    2015-10-01

    Many species of bacteria use a cell-cell communication system called quorum sensing (QS) to coordinate group activities. QS systems frequently regulate the production of exoproducts. Some of these products, such as proteases, are "public goods" that are shared among the population and vulnerable to cheating by nonproducing members of the population. Because the QS system of the opportunistic pathogen Pseudomonas aeruginosa regulates several public goods, it can serve as a model for studying cooperation. Bacteria also commonly regulate antimicrobial production through QS. In this study, we focused on the hypothesis that QS-regulated antimicrobials may be important for P. aeruginosa to protect against cheating by another bacterial species, Burkholderia multivorans. We assessed laboratory cocultures of P. aeruginosa and B. multivorans and investigated the importance of three P. aeruginosa QS-regulated antimicrobials, hydrogen cyanide, rhamnolipids, and phenazines, for competition. We found that P. aeruginosa dominates cocultures with B. multivorans and that the three antimicrobials together promote P. aeruginosa competitiveness, with hydrogen cyanide contributing the greatest effect. We show that these QS-regulated antimicrobials are also critical for P. aeruginosa to prevent B. multivorans from cheating under nutrient conditions where both species require a P. aeruginosa quorum-regulated protease for growth. Together our results highlight the importance of antimicrobials in protecting cooperating populations from exploitation by other species that can act as cheaters. Cooperative behaviors are threatened by social cheating, wherein individuals do not produce but nonetheless benefit from shared public goods. Bacteria have been shown to use several genetic mechanisms to restrain the emergence of cheaters from within the population, but public goods might also be used by other bacterial species in the vicinity. We demonstrate that a public good produced by Pseudomonas

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

    Science.gov (United States)

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

    2016-09-01

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

  4. Pseudomonas aeruginosa Microcolonies in Coronary Thrombi from Patients with ST-Segment Elevation Myocardial Infarction.

    Science.gov (United States)

    Hansen, Gorm Mørk; Belstrøm, Daniel; Nilsson, Martin; Helqvist, Steffen; Nielsen, Claus Henrik; Holmstrup, Palle; Tolker-Nielsen, Tim; Givskov, Michael; Hansen, Peter Riis

    2016-01-01

    Chronic infection is associated with an increased risk of atherothrombotic disease and direct bacterial infection of arteries has been suggested to contribute to the development of unstable atherosclerotic plaques. In this study, we examined coronary thrombi obtained in vivo from patients with ST-segment elevation myocardial infarction (STEMI) for the presence of bacterial DNA and bacteria. Aspirated coronary thrombi from 22 patients with STEMI were collected during primary percutaneous coronary intervention and arterial blood control samples were drawn from radial or femoral artery sheaths. Analyses were performed using 16S polymerase chain reaction and with next-generation sequencing to determine bacterial taxonomic classification. In selected thrombi with the highest relative abundance of Pseudomonas aeruginosa DNA, peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) with universal and species specific probes was performed to visualize bacteria within thrombi. From the taxonomic analysis we identified a total of 55 different bacterial species. DNA from Pseudomonas aeruginosa represented the only species that was significantly associated with either thrombi or blood and was >30 times more abundant in thrombi than in arterial blood (pthrombi using universal and P. aeruginosa-specific PNA-FISH probes. P. aeruginosa and vascular biofilm infection in culprit lesions may play a role in STEMI, but causal relationships remain to be determined.

  5. Clearance of Pseudomonas aeruginosa Foreign-Body Biofilm Infections through Reduction of the Cyclic Di-GMP Level in the Bacteria

    DEFF Research Database (Denmark)

    Christensen, Louise D.; van Gennip, Maria; Rybtke, Morten Theil

    2013-01-01

    Opportunistic pathogenic bacteria can engage in biofilm-based infections that evade immune responses and develop into chronic conditions. Because conventional antimicrobials cannot efficiently eradicate biofilms, there is an urgent need to develop alternative measures to combat biofilm infections...

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

    Science.gov (United States)

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

    1992-01-01

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

  7. Ciprofloxacin susceptibility of Pseudomonas aeruginosa isolates from keratitis

    DEFF Research Database (Denmark)

    Lomholt, JA; Kilian, Mogens

    2003-01-01

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

  8. Development of New Therapeutics Targeting Biofilm Formation by the Opportunistic Pulmonary Pathogens Pseudomonas aeruginosa and Aspergillus Fumigatus

    Science.gov (United States)

    2017-10-01

    aeurginosa (PA) and fungus Aspergillus fumigatus (AF) are common causes of pulmonary disease in immunocompromised patients. During infection, both...The bacteria Pseudomonas aeruginosa (PA) and fungus Aspergillus fumigatus (AF) are common causes of pulmonary disease in immunocompromised patients...to Project: Ms. Smith has performed work in the area of combined error -control and constrained coding. Funding Support: The Ford

  9. Synergistic effect of 14-alpha-lipoyl andrographolide and various antibiotics on the formation of biofilms and production of exopolysaccharide and pyocyanin by Pseudomonas aeruginosa.

    Science.gov (United States)

    Zeng, Xiangping; Liu, Xiangyang; Bian, Jiang; Pei, Gang; Dai, Huanqin; Polyak, Steven W; Song, Fuhang; Ma, Li; Wang, Yuqiang; Zhang, Lixin

    2011-06-01

    Pseudomonas aeruginosa produces a biofilm that provides the bacteria with an effective barrier against antibiotics. Here, we investigated the synergy of various antibiotics with 14-alpha-lipoyl andrographolide (AL-1), focusing upon synthesis of the biofilm. AL-1 also inhibited the production of the exopolysaccharide and pyocyanin components. We propose that AL-1 may potentially serve as a cotherapy to combat P. aeruginosa.

  10. Mucoid Pseudomonas aeruginosa isolates maintain the biofilm formation capacity and the gene expression profiles during the chronic lung infection of CF patients

    DEFF Research Database (Denmark)

    Lee, Bao le ri; Schjerling, Charlotte K.; Kirkby, Nikolai

    2011-01-01

    Phenotypic and genotypic diversifications of Pseudomonas aeruginosa in the airways of patients with cystic fibrosis (CF) promote long-term survival of bacteria during chronic lung infection. Twelve clonally related, sequential mucoid and non-mucoid paired P. aeruginosa isolates obtained from three...

  11. The Pseudomonas aeruginosa opportunistic pathogen and human infections.

    Science.gov (United States)

    de Bentzmann, Sophie; Plésiat, Patrick

    2011-07-01

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

  12. Effect of dietary monosaccharides on Pseudomonas aeruginosa virulence.

    Science.gov (United States)

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

    2013-02-01

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

  13. In situ growth rates and biofilm development of Pseudomonas aeruginosa populations in chronic lung infections

    DEFF Research Database (Denmark)

    Yang, L.; Haagensen, J.A.; Jelsbak, L.

    2008-01-01

    infections in cystic fibrosis (CF) patients for more than 20 years. We used fluorescence in situ hybridization (FISH) directly on sputum specimens to examine the spatial distribution of the infecting P. aeruginosa cells. Mucoid variants were present in sputum as cell clusters surrounded by an extracellular......The growth dynamics of bacterial pathogens within infected hosts are a fundamental but poorly understood feature of most infections. We have focused on the in situ distribution and growth characteristics of two prevailing and transmissible Pseudomonas aeruginosa clones that have caused chronic lung...... matrix, whereas nonmucoid variants were present mainly as dispersed cells. To obtain estimates of the growth rates of P. aeruginosa in CF lungs, we used quantitative FISH to indirectly measure growth rates of bacteria in sputum samples (reflecting the in vivo lung conditions). The concentration of r...

  14. Molecular epidemiology and dynamics of Pseudomonas aeruginosa populations in lungs of cystic fibrosis patients

    DEFF Research Database (Denmark)

    Jelsbak, Lars; Johansen, Helle Krogh; Frost, Anne Louise Viborg

    2007-01-01

    The ability to establish lifelong persistent infections is a fundamental aspect of the interactions between many pathogenic microorganisms and their mammalian hosts. One example is chronic lung infections by the opportunistic pathogen Pseudomonas aeruginosa in cystic fibrosis (CF) patients....... This infection process is associated with extensive genetic adaptation and microevolution of the infecting bacteria. Through investigations of P. aeruginosa populations and infection dynamics in a group of CF patients followed at the Danish CF Clinic in Copenhagen, we have identified two distinct and dominant...... success. In contrast, we show that adaptive traits commonly associated with establishment of chronic P. aeruginosa infections of CF patients, such as transition to the mucoid phenotype and production of virulence factors, play minor roles in the ability of the two dominant clones to spread among patients...

  15. In situ growth rates and biofilm development of Pseudomonas aeruginosa populations in chronic lung infections

    DEFF Research Database (Denmark)

    Yang, Lei; Haagensen, Janus Anders Juul; Jelsbak, Lars

    2008-01-01

    The growth dynamics of bacterial pathogens within infected hosts are a fundamental but poorly understood feature of most infections. We have focused on the in situ distribution and growth characteristics of two prevailing and transmissible Pseudomonas aeruginosa clones that have caused chronic lung...... infections in cystic fibrosis (CF) patients for more than 20 years. We used fluorescence in situ hybridization (FISH) directly on sputum specimens to examine the spatial distribution of the infecting P. aeruginosa cells. Mucoid variants were present in sputum as cell clusters surrounded by an extracellular...... matrix, whereas nonmucoid variants were present mainly as dispersed cells. To obtain estimates of the growth rates of P. aeruginosa in CF lungs, we used quantitative FISH to indirectly measure growth rates of bacteria in sputum samples (reflecting the in vivo lung conditions). The concentration of r...

  16. Biofilm formation by Pseudomonas aeruginosa wild type, flagella and type IV pili mutants

    DEFF Research Database (Denmark)

    Klausen, M.; Heydorn, Arne; Ragas, Paula Cornelia

    2003-01-01

    Biofilm formation by Gfp-tagged Pseudomonas aeruginosa PAO1 wild type, flagella and type IV pili mutants in flow chambers irrigated with citrate minimal medium was characterized by the use of confocal laser scanning microscopy and comstat image analysis. Flagella and type IV pili were not necessary...... for P. aeruginosa initial attachment or biofilm formation, but the cell appendages had roles in biofilm development, as wild type, flagella and type IV pili mutants formed biofilms with different structures. Dynamics and selection during biofilm formation were investigated by tagging the wild type...... and flagella/type IV mutants with Yfp and Cfp and performing time-lapse confocal laser scanning microscopy in mixed colour biofilms. The initial microcolony formation occurred by clonal growth, after which wild-type P. aeruginosa bacteria spread over the substratum by means of twitching motility. The wild-type...

  17. Up-regulating pyocyanin production by amino acid addition for early electrochemical identification of Pseudomonas aeruginosa.

    Science.gov (United States)

    Sismaet, Hunter J; Webster, Thaddaeus A; Goluch, Edgar D

    2014-09-07

    This work focuses on developing a faster method for electrochemically detecting a Pseudomonas aeruginosa infection through the addition of amino acids to cell culture samples. We performed square-wave voltammetry measurements of pyocyanin produced by P. aeruginosa using commercially available carbon-based electrodes connected to a Ag/AgCl reference. The electrochemical response resulting from the production of pyocyanin by bacteria was measured in the presence of various amino acids while varying three different culturing parameters: liquid media type (trypticase soy broth vs. M63 minimal media); concentration of amino acids in the solution; and initial concentration of the P. aeruginosa in the solution. Our results demonstrate a faster and stronger electrochemical response in media containing tyrosine and valine at elevated concentrations, lending promise to using amino acids as up-regulatory molecules for faster bacterial detection.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2017-10-01

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

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

    Science.gov (United States)

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

    2014-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Anoop M

    2017-05-01

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

  2. Neonatal Orbital Abscess Secondary to Pseudomonas Aeruginosa Conjunctivitis.

    Science.gov (United States)

    Yazici, Bulent; Orucov, Nesimi; Ibrahimzade, Gunay

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

  3. Pseudomonas aeruginosa identified as a key pathogen in hospitalised children with aspiration pneumonia and a high aspiration risk.

    Science.gov (United States)

    Ashkenazi-Hoffnung, Liat; Ari, Anne; Bilavsky, Efraim; Scheuerman, Oded; Amir, Jacob; Prais, Dario

    2016-12-01

    Data on the causative pathogens and optimal empirical therapy of aspiration pneumonia in children are limited. This study sought to describe the bacteriology of aspiration pneumonia in hospitalised children with a high aspiration risk. Respiratory tract specimens were prospectively collected using the induced sputum technique from children with a high aspiration risk who were hospitalised for aspiration pneumonia in a tertiary paediatric medical centre from 2009 to 2014. Clinical, microbiological and treatment data were recorded and analysed for each admission. The cohort comprised 50 children with 235 hospital admissions. Of the 183 respiratory tract cultures performed, 110 were positive for bacteria, with 169 isolates, mostly Gram-negative. The most common Gram-negative pathogen was Pseudomonas aeruginosa. If patients had Pseudomonas aeruginosa isolation, the risk of them having the pathogen again was 81%. The multivariate analysis showed that the use of antibiotic prophylaxis and number of hospitalisations were significantly associated with Pseudomonas aeruginosa isolation. Gram-negative bacilli, especially Pseudomonas aeruginosa, were the major causative agents of paediatric aspiration pneumonia in our study. Empiric antipseudomonas treatment should be considered, particularly in patients who are receiving antibiotic prophylaxis, have experienced recurrent hospitalisations or with previous respiratory cultures that showed Pseudomonas aeruginosa isolation. ©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

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

    OpenAIRE

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

    1989-01-01

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

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

    OpenAIRE

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

    2017-01-01

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

  6. Extracellular DNA Shields against Aminoglycosides in Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  7. Hyperbaric oxygen sensitizes anoxic Pseudomonas aeruginosa biofilm to ciprofloxacin

    DEFF Research Database (Denmark)

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

    2017-01-01

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

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

    Science.gov (United States)

    Lee, Keehoon; Yoon, Sang Sun

    2017-06-28

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

  9. Outbreak of Pseudomonas aeruginosa bacteraemia in a haematology department

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  10. Clinical implications of Pseudomonas aeruginosa location in the lungs of patients with cystic fibrosis.

    Science.gov (United States)

    Moore, J E; Mastoridis, P

    2017-06-01

    Pseudomonas aeruginosa is the leading cause of lung infection in patients with cystic fibrosis (CF) and is associated with significant morbidity and mortality. Antibiotics are regarded as the foundational pharmacological treatment for the suppressive management of chronic P. aeruginosa infections and to eradicate the first infection by P. aeruginosa. Inhalation remains a preferred route for drug administration, providing direct access to the site of infection while minimizing systemic side effects. Effective suppressive management of P. aeruginosa infections, however, requires an understanding of the location of the bacteria in the lungs and consideration of the factors that could limit access of the inhaled antibiotic to the infected area. This review provides a systematic assessment of the scientific literature to gain insight into the location of P. aeruginosa in the lungs of patients with CF and its clinical implications. The characteristics of antibiotic inhalation systems are also discussed in this context. We reviewed evidence-based literature from both human and animal studies in which P. aeruginosa lung location was reported. Relevant publications were identified through a screening strategy and summarized by reported P. aeruginosa location. Most areas of the conductive and respiratory zones of the lungs are susceptible to P. aeruginosa colonization. Deposition of an inhaled antibiotic is dependent on the device and formulation characteristics, as well as the ability of the patient to generate sufficient inhaled volume. As patients with CF often experience a decline in lung function, the challenge is to ensure that the inhaled antibiotic can be delivered throughout the bronchial tree. An effective drug delivery system that can target P. aeruginosa in both the respiratory and conductive zones is required. The chosen inhalation device should also offer a drug formulation that can be quickly and effectively delivered to specific lung locations, with

  11. Experimental Pseudomonas aeruginosa mediated rhino sinusitis in mink.

    Science.gov (United States)

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

    2017-05-01

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

  12. Elimination of Pseudomonas aeruginosa through Efferocytosis upon Binding to Apoptotic Cells

    Science.gov (United States)

    Arias, Paula; Kierbel, Arlinet

    2016-01-01

    For opportunistic pathogens such as Pseudomonas aeruginosa, the mucosal barrier represents a formidable challenge. Infections develop only in patients with altered epithelial barriers. Here, we showed that P. aeruginosa interacts with a polarized epithelium, adhering almost exclusively at sites of multi-cellular junctions. In these sites, numerous bacteria attach to an extruded apoptotic cell or apoptotic body. This dead cell tropism is independent of the type of cell death, as P. aeruginosa also binds to necrotic cells. We further showed that P. aeruginosa is internalized through efferocytosis, a process in which surrounding epithelial cells engulf and dispose of extruded apoptotic cells. Intracellularly, along with apoptotic cell debris, P. aeruginosa inhabits an efferocytic phagosome that acquires lysosomal features, and is finally killed. We propose that elimination of P. aeruginosa through efferocytosis is part of a host defense mechanism. Our findings could be relevant for the study of cystic fibrosis, which is characterized by an exacerbated number of apoptotic cells and ineffective efferocytosis. PMID:27977793

  13. Exopolysaccharide-Repressing Small Molecules with Antibiofilm and Antivirulence Activity against Pseudomonas aeruginosa.

    Science.gov (United States)

    van Tilburg Bernardes, Erik; Charron-Mazenod, Laetitia; Reading, David J; Reckseidler-Zenteno, Shauna L; Lewenza, Shawn

    2017-05-01

    Biofilm formation is a universal virulence strategy in which bacteria grow in dense microbial communities enmeshed within a polymeric extracellular matrix that protects them from antibiotic exposure and the immune system. Pseudomonas aeruginosa is an archetypal biofilm-forming organism that utilizes a biofilm growth strategy to cause chronic lung infections in cystic fibrosis (CF) patients. The extracellular matrix of P. aeruginosa biofilms is comprised mainly of exopolysaccharides (EPS) and DNA. Both mucoid and nonmucoid isolates of P. aeruginosa produce the Pel and Psl EPS, each of which have important roles in antibiotic resistance, biofilm formation, and immune evasion. Given the central importance of the EPS for biofilms, they are attractive targets for novel anti-infective compounds. In this study, we used a high-throughput gene expression screen to identify compounds that repress expression of the pel genes. The pel repressors demonstrated antibiofilm activity against microplate and flow chamber biofilms formed by wild-type and hyperbiofilm-forming strains. To determine the potential role of EPS in virulence, pel/psl mutants were shown to have reduced virulence in feeding behavior and slow killing virulence assays in Caenorhabditis elegans The antibiofilm molecules also reduced P. aeruginosa PAO1 virulence in the nematode slow killing model. Importantly, the combination of antibiotics and antibiofilm compounds increased killing of P. aeruginosa biofilms. These small molecules represent a novel anti-infective strategy for the possible treatment of chronic P. aeruginosa infections. Copyright © 2017 American Society for Microbiology.

  14. Honey as an antimicrobial agent against Pseudomonas aeruginosa isolated from infected wounds

    Directory of Open Access Journals (Sweden)

    Vishnu Prasad Shenoy

    2012-01-01

    Full Text Available Background: As natural products garner attention in the medical field due to emergence of antibiotic resistant strains of bacteria, honey is valued for its antibacterial activity. Objective: Fifty strains of Pseudomonas aeruginosa isolated from infected wounds were evaluated for their antibacterial action using honey in comparison with different antibiotics and Dettol. Methodology and Results: All the strains were found to be sensitive to honey at a minimum inhibitory concentration of 20% in comparison with Dettol at 10% using agar dilution method. In the second step, the time kill assay was performed on five isolates of P. aeruginosa to demonstrate the bactericidal activity of honey at different dilutions of honey ranging from 20% to 100% at regular time intervals. All the isolates of P. aeruginosa tested were killed in 12-24 h depending on the dilutions of the honey tested. Thus, honey could prevent the growth of P. aeruginosa even if it was diluted by deionized water by fivefolds in vitro. Honey had almost uniform bactericidal activity against P. aeruginosa irrespective of their susceptibility to different classes of antibiotics. Conclusion: Honey which is a natural, non-toxic, and an inexpensive product has activity against the P. aeruginosa isolated from infected wounds may make it an alternative topical choice in the treatment of wound infections.

  15. Honey as an antimicrobial agent against pseudomonas aeruginosa isolated from infected wounds.

    Science.gov (United States)

    Shenoy, Vishnu Prasad; Ballal, Mamatha; Shivananda, Pg; Bairy, Indira

    2012-04-01

    As natural products garner attention in the medical field due to emergence of antibiotic resistant strains of bacteria, honey is valued for its antibacterial activity. Fifty strains of Pseudomonas aeruginosa isolated from infected wounds were evaluated for their antibacterial action using honey in comparison with different antibiotics and Dettol. All the strains were found to be sensitive to honey at a minimum inhibitory concentration of 20% in comparison with Dettol at 10% using agar dilution method. In the second step, the time kill assay was performed on five isolates of P. aeruginosa to demonstrate the bactericidal activity of honey at different dilutions of honey ranging from 20% to 100% at regular time intervals. All the isolates of P. aeruginosa tested were killed in 12-24 h depending on the dilutions of the honey tested. Thus, honey could prevent the growth of P. aeruginosa even if it was diluted by deionized water by fivefolds in vitro. Honey had almost uniform bactericidal activity against P. aeruginosa irrespective of their susceptibility to different classes of antibiotics. Honey which is a natural, non-toxic, and an inexpensive product has activity against the P. aeruginosa isolated from infected wounds may make it an alternative topical choice in the treatment of wound infections.

  16. Inhibition of Biofilm Formation by Esomeprazole in Pseudomonas aeruginosa and Staphylococcus aureus

    Science.gov (United States)

    Singh, Vandana; Arora, Vaneet; Alam, M. Jahangir

    2012-01-01

    Staphylococcus aureus and Pseudomonas aeruginosa are common nosocomial pathogens responsible for biofilm-associated infections. Proton pump inhibitors (PPI), such as esomeprazole, may have novel antimicrobial properties. The objective of this study was to assess whether esomeprazole prevents sessile bacterial growth and biofilm formation and whether it may have synergistic killing effects with standard antibiotics. The antibiofilm activity of esomeprazole at 0.25 mM was tested against two strains each of S. aureus and P. aeruginosa. Bacterial biofilms were prepared using a commercially available 96-peg-plate Calgary biofilm device. Sessile bacterial CFU counts and biomass were assessed during 72 hours of esomeprazole exposure. The killing activities after an additional 24 hours of vancomycin (against S. aureus) and meropenem (against P. aeruginosa) treatment with or without preexposure to esomeprazole were also assessed by CFU and biomass analyses. P. aeruginosa and S. aureus strains exposed to esomeprazole displayed decreased sessile bacterial growth and biomass (P esomeprazole-exposed P. aeruginosa and S. aureus strains compared to controls (P esomeprazole-exposed strains (P esomeprazole-treated bacteria compared to untreated controls exposed to conventional antibiotics (P esomeprazole compared to untreated controls. In conclusion, esomeprazole demonstrated an antibiofilm effect against biofilm-producing S. aureus and P. aeruginosa. PMID:22664967

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

    Science.gov (United States)

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

    2016-07-01

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

  18. Reduction of PCN biosynthesis by NO in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Lei Gao

    2016-08-01

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

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

    LENUS (Irish Health Repository)

    Keating, Deirdre

    2013-03-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  2. Swimming Motility Mediates the Formation of Neutrophil Extracellular Traps Induced by Flagellated Pseudomonas aeruginosa

    Science.gov (United States)

    Sil, Payel; Chassaing, Benoit; Yoo, Dae-goon; Gewirtz, Andrew T.; Goldberg, Joanna B.; McCarter, Linda L.; Rada, Balázs

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen causing severe infections often characterized by robust neutrophilic infiltration. Neutrophils provide the first line of defense against P. aeruginosa. Aside from their defense conferred by phagocytic activity, neutrophils also release neutrophil extracellular traps (NETs) to immobilize bacteria. Although NET formation is an important antimicrobial process, the details of its mechanism are largely unknown. The identity of the main components of P. aeruginosa responsible for triggering NET formation is unclear. In this study, our focus was to identify the main bacterial factors mediating NET formation and to gain insight into the underlying mechanism. We found that P. aeruginosa in its exponential growth phase promoted strong NET formation in human neutrophils while its NET-inducing ability dramatically decreased at later stages of bacterial growth. We identified the flagellum as the primary component of P. aeruginosa responsible for inducing NET extrusion as flagellum-deficient bacteria remained seriously impaired in triggering NET formation. Purified P. aeruginosa flagellin, the monomeric component of the flagellum, does not stimulate NET formation in human neutrophils. P. aeruginosa-induced NET formation is independent of the flagellum-sensing receptors TLR5 and NLRC4 in both human and mouse neutrophils. Interestingly, we found that flagellar motility, not flagellum binding to neutrophils per se, mediates NET release induced by flagellated bacteria. Immotile, flagellar motor-deficient bacterial strains producing paralyzed flagella did not induce NET formation. Forced contact between immotile P. aeruginosa and neutrophils restored their NET-inducing ability. Both the motAB and motCD genetic loci encoding flagellar motor genes contribute to maximal NET release; however the motCD genes play a more important role. Phagocytosis of P. aeruginosa and superoxide production by neutrophils were also largely dependent upon

  3. Carbon Sources Tune Antibiotic Susceptibility in Pseudomonas aeruginosa via Tricarboxylic Acid Cycle Control.

    Science.gov (United States)

    Meylan, Sylvain; Porter, Caroline B M; Yang, Jason H; Belenky, Peter; Gutierrez, Arnaud; Lobritz, Michael A; Park, Jihye; Kim, Sun H; Moskowitz, Samuel M; Collins, James J

    2017-02-16

    Metabolically dormant bacteria present a critical challenge to effective antimicrobial therapy because these bacteria are genetically susceptible to antibiotic treatment but phenotypically tolerant. Such tolerance has been attributed to impaired drug uptake, which can be reversed by metabolic stimulation. Here, we evaluate the effects of central carbon metabolite stimulations on aminoglycoside sensitivity in the pathogen Pseudomonas aeruginosa. We identify fumarate as a tobramycin potentiator that activates cellular respiration and generates a proton motive force by stimulating the tricarboxylic acid (TCA) cycle. In contrast, we find that glyoxylate induces phenotypic tolerance by inhibiting cellular respiration with acetyl-coenzyme A diversion through the glyoxylate shunt, despite drug import. Collectively, this work demonstrates that TCA cycle activity is important for both aminoglycoside uptake and downstream lethality and identifies a potential strategy for potentiating aminoglycoside treatment of P. aeruginosa infections. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Effects of physical factors on the swarming motility of text itPseudomonas aeruginosa

    Science.gov (United States)

    Si, Tieyan; Ma, Zidong; Tang, Wai Shing; Yang, Alexander; Tang, Jay

    Many species of bacteria can spread over a semi-solid surface via a particular form of collective motion known as surface swarming. Using Pseudomonas aeruginosa as a model organism, we investigate physical factors that either facilitate or restrict the swarming motility. The semi-solid surface is typically formed by 0.5-1% agar containing essential nutrients for the bacterial growth and proliferation. Most bacterial species, including P. aeruginosa, synthesize bio-surfactants to aid in swarming. We found addition of exogenous surfactants such as triton into the agar matrix enhances the swarming. In contrast, increasing agar percentage, infusing osmolites, and adding viscous agents all decrease swarming. We propose that the swarming speed is restricted by the rate of water supply from within the agar gel and by the line tension at the swarm front involving three materials in contact: the air, the bacteria propelled liquid film, and the agar substrate.

  5. Antibiofilm and anti-infection of a marine bacterial exopolysaccharide against Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Shimei eWu

    2016-02-01

    Full Text Available Pseudomonas aeruginosa is a well-known pathogenic bacterium that forms biofilms and produces virulence factors, thus leading to major problems in many fields, such as clinical infection, food contamination and marine biofouling. In this study, we report the purification and characterization of an exopolysaccharide EPS273 from the culture supernatant of marine bacterium Pseudomonas stutzeri 273. The exopolysaccharide EPS273 not only effectively inhibits biofilm formation but also disperses preformed biofilm of Pseudomonas aeruginosa PAO1. High performance liquid chromatography traces of the hydrolyzed polysaccharides shows that EPS273 primarily consists of glucosamine, rhamnose, glucose and mannose. Further investigation demonstrates that EPS273 reduces the production of the virulence factors pyocyanin, exoprotease and rhamnolipid, and the virulence of P. aeruginosa PAO1 to human lung cells A549 and zebrafish embryos is also obviously attenuated by EPS273. In addition, EPS273 also greatly reduces the production of hydrogen peroxide (H2O2 and extracellular DNA (eDNA, which are important factors for biofilm formation. Furthermore, EPS273 exhibits strong antioxidant potential by quenching hydroxyl and superoxide anion radicals. Notably, the antibiofouling activity of EPS273 is observed in the marine environment up to two weeks according to the amounts of bacteria and diatoms in the glass slides submerged in the ocean. Taken together, the properties of EPS273 indicate that it has a promising prospect in combating bacterial biofilm-associated infection, food-processing contamination and marine biofouling.

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

    Science.gov (United States)

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

    1997-12-18

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    National Research Council Canada - National Science Library

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

    2015-01-01

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

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

    National Research Council Canada - National Science Library

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

    2003-01-01

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

  10. Reexamining intra and extracellular metabolites produced by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Maria Shuja

    2016-02-01

    Full Text Available Objective: To isolate, screen and analyze bacteria from different areas of Pakistan for the production of antimicrobial compounds, zinc solubilization and bioplastic production. Methods: Isolation and purification was proceeding with streak plate method. Antagonistic assay was completed with well diffusion and thin-layer chromatography. In vivo analysis of bioplastic was analyzed with Nile blue fluorescence under UV and Sudan staining. Results: A total of 18 bacterial strains purified from soil samples while 148 strains form stock cultures were used. Out of 166 only 94 showed antimicrobial activity against each of Grampositive and Gram-negative; cocci and rods. In case of heavy metal (ZnO and Zn3(PO42.4H2O solubilization, 54 strains solubilized ZnO and 23 strains solubilized Zn3(PO42.4H2O, while 127 strains grown on polyhydroxyalkanoate detection meedia supplemented with Nile blue medium showed bioplastic production by producing fluorescence under UV light. Four bacterial strains (coded as 100, 101, 104 and 111 were selected for further characterization. Induction time assay showed that strains 101, 104, and 111 showed inhibitory activity after 4 h of incubation while strain 100 showed after 8 h. All four strains were tolerable to the maximum concentration of ZnO. Amplified products of both 16S rRNA and PhaC gene fragments of strain 111 were sequenced and submitted to GenBank as accession numbers EU781525 and EU781526. Conclusions: Bacterial strain Pseudomonas aeruginosa-111 has potential to utilize as biofertilize and bioplastic producer.

  11. Genetic and Functional Diversity of Pseudomonas aeruginosa Lipopolysaccharide

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    1979-01-01

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

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

    Science.gov (United States)

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

    2002-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Seda Arat

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

  15. Pyocyanin promotes extracellular DNA release in Pseudomonas aeruginosa.

    Science.gov (United States)

    Das, Theerthankar; Manefield, Mike

    2012-01-01

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

  16. Pyocyanin promotes extracellular DNA release in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Theerthankar Das

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

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

    Science.gov (United States)

    Juan, Carlos; Peña, Carmen; Oliver, Antonio

    2017-02-15

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

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

    Science.gov (United States)

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

    2017-01-01

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

  19. Specific IgA against Pseudomonas aeruginosa in severe COPD

    Science.gov (United States)

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

    2017-01-01

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

  20. Ocorrência de Pseudomonas aeruginosa em água potável = Occurrence of Pseudomonas aeruginosa in drinking water

    Directory of Open Access Journals (Sweden)

    Tânia Ueda-Nakamura

    2006-01-01

    Full Text Available Foram analisadas 413 amostras de água potável do sistema principal e do sistema secundário em Bandeirantes, Estado do Paraná, através de membrana filtrante para P. aeruginosa e bactérias heterotróficas em ágar Plate Count. Coliformes totais e fecais foram determinados pelo método dos tubos múltiplos. A qualidade físico-química da água foideterminada em termos de turbidez, pH, cloro, flúor, alcalinidade, cor, oxigênio dissolvido, dureza e matéria orgânica. Das amostras examinadas, 10,41% estavam contaminadas por P. aeruginosa, incluindo 23,53% das amostras do sistema de água secundário, e 8,56% das amostras do sistema de água principal. Somente uma amostra apresentou contagem de bactérias heterotróficas acima do nível máximo recomendado. P. aeruginosa isoladas foram testadas para sensibilidade ao cloro livre e sobreviveram a uma concentração de cloro trêsvezes acima da concentração mínima usada. É recomendada a determinação periódica de Pseudomonas em adição aos dados rotineiramente coletados na maioria dos sistemas de abastecimento.A total of 413 samples of drinking water, taken from principal and secondary water systems in the municipality of Bandeirantes, state of Paraná, southern Brazil, were analyzed through membrane filtration for P. aeruginosa and on Plate Count agar for heterotrophic bacteria.Total and fecal coliforms were determined by multiple dilution tube methods. Turbidity, pH, chlorine, fluoride, alkalinity, color, dissolved oxygen, hardness and organic matter were also measured. Of the 413 samples examined, 10.41% were contaminated by P. aeruginosa,including 23,53% of the water from secondary water system, 8,56% of the water from principal water system. No coliform was found in any of the samples. One sample counted above the maximum heterotrophic bacteria level permitted. P. aeruginosa isolated from the water samples were tested for chlorine sensitivity and survived up to three times the

  1. Effect of novel antibacterial gallium-carboxymethyl cellulose on Pseudomonas aeruginosa.

    Science.gov (United States)

    Valappil, Sabeel P; Yiu, Humphrey H P; Bouffier, Laurent; Hope, Christopher K; Evans, Gary; Claridge, John B; Higham, Susan M; Rosseinsky, Matthew J

    2013-02-07

    Gallium has emerged as a new therapeutic agent due partly to the scarcity in development of new antibiotics. In this study, a novel antibacterial gallium exchanged carboxymethyl cellulose (Ga-CMC) has been developed and tested for the susceptibility on a common bacteria, Pseudomonas aeruginosa. The results show that an increase in average molecular weight (MW) from 90 k, 250 k to 700 k of Ga-CMC caused a decrease in antimicrobial activity against planktonic P. aeruginosa. Gallium loading of the Ga-CMC (250 k) samples was altered by varying the amount of functionality (0.7, 0.9 and 1.2 acid groups per mole of carbohydrate) which affected also its antimicrobial activity against planktonic P. aeruginosa. Further, the ability to prevent the growth of biofilms of P. aeruginosa was tested on MW = 250 k samples with 0.9 acid groups per mole of carbohydrate as this sample showed the most promising activity against planktonic P. aeruginosa. Gallium was found to reduce biofilm growth of P. aeruginosa with a maximum effect (0.85 log(10) CFU reduction compared to sodium-carboxymethyl cellulose, Na-CMC) after 24 h. Results of the solubility and ion exchange studies show that this compound is suitable for the controlled release of Ga(3+) upon their breakdown in the presence of bacteria. SEM EDX analysis confirmed that Ga(3+) ions are evenly exchanged on the cellulose surface and systematic controls were carried out to ensure that antibacterial activity is solely due to the presence of gallium as samples intrinsic acidity or nature of counterion did not affect the activity. The results presented here highlight that Ga-CMC may be useful in controlled drug delivery applications, to deliver gallium ions in order to prevent infections due to P. aeruginosa biofilms.

  2. Novel drug targets in cell wall biosynthesis exploited by gene disruption in Pseudomonas aeruginosa.

    Science.gov (United States)

    Elamin, Ayssar A; Steinicke, Susanne; Oehlmann, Wulf; Braun, Yvonne; Wanas, Hanaa; Shuralev, Eduard A; Huck, Carmen; Maringer, Marko; Rohde, Manfred; Singh, Mahavir

    2017-01-01

    For clinicians, Pseudomonas aeruginosa is a nightmare pathogen that is one of the top three causes of opportunistic human infections. Therapy of P. aeruginosa infections is complicated due to its natural high intrinsic resistance to antibiotics. Active efflux and decreased uptake of drugs due to cell wall/membrane permeability appear to be important issues in the acquired antibiotic tolerance mechanisms. Bacterial cell wall biosynthesis enzymes have been shown to be essential for pathogenicity of Gram-negative bacteria. However, the role of these targets in virulence has not been identified in P. aeruginosa. Here, we report knockout (k.o) mutants of six cell wall biosynthesis targets (murA, PA4450; murD, PA4414; murF, PA4416; ppiB, PA1793; rmlA, PA5163; waaA, PA4988) in P. aeruginosa PAO1, and characterized these in order to find out whether these genes and their products contribute to pathogenicity and virulence of P. aeruginosa. Except waaA k.o, deletion of cell wall biosynthesis targets significantly reduced growth rate in minimal medium compared to the parent strain. The k.o mutants showed exciting changes in cell morphology and colonial architectures. Remarkably, ΔmurF cells became grossly enlarged. Moreover, the mutants were also attenuated in vivo in a mouse infection model except ΔmurF and ΔwaaA and proved to be more sensitive to macrophage-mediated killing than the wild-type strain. Interestingly, the deletion of the murA gene resulted in loss of virulence activity in mice, and the virulence was restored in a plant model by unknown mechanism. This study demonstrates that cell wall targets contribute significantly to intracellular survival, in vivo growth, and pathogenesis of P. aeruginosa. In conclusion, these findings establish a link between cell wall targets and virulence of P. aeruginosa and thus may lead to development of novel drugs for the treatment of P. aeruginosa infection.

  3. Pattern formation in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Parsek, Matthew R.; Tolker-Nielsen, Tim

    2008-01-01

    Bacteria are capable of forming elaborate multicellular communities called biofilms. Pattern formation in biofilms depends on cell proliferation and cellular migration in response to the available nutrients and other external cues, as well as on self-generated intercellular signal molecules and t...

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

    Science.gov (United States)

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

    2013-12-01

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

  5. Functional study of elafin cleaved by Pseudomonas aeruginosa metalloproteinases

    Science.gov (United States)

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

    2012-01-01

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

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

    LENUS (Irish Health Repository)

    Guyot, Nicolas

    2010-06-01

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

  7. PEMERIKSAAN DAYA HAMBAT EKTRAK METANOL DAUN TRISTANIA SUBAURICULATA KING TERHADAP PERTUMBUHAN KUMAN PSEUDOMONAS AERUGINOSA DAN STAPHYLOCOCCUS AUREUS

    Directory of Open Access Journals (Sweden)

    Yustini Alioes

    2011-05-01

    Full Text Available AbstrakTristania subauriculata King dikenal oleh penduduk sekitar Kelok Sembilan, Payakumbuh sebagai obat untuk mengobati penyakit kulit. Diduga Tristania subauriculata King mengandung suatu senyawa bioaktif yang bersifat sebagai anti bakteri.Untuk melihat efektifitas ekstrak metanol daun Tristania subauriculata King dalam menghambat pertumbuhan kuman Pseudomonas aeruginosa dan Staphylococcus aureus, telah dilakukan penelitian secara invitro dengan menggunakan metode difusi agar, pengamatan dilakukan dengan mengukur diameter daerah hambat yang terbentuk pada agar.Dari penelitian didapatkan adanya daya hambat ekstrak metanol daun Tristania subauriculata King 15% b/v dalam menghambat pertumbuhan kuman Pseudomonas aeruginosa dan Staphylococcus aureus. Daya hambat ini meningkat pada konsentrasi 30% b/v, 45% b/v, dan daya hambat terbesar pada konsentrasi 60% b/v yang terlihat dengan semakin besarnya diameter daerah bebas kuman yang dihasilkan.Kata kunci : Ekstrak Metanol daun Tristania subauriculata King, Diameterhambat, Pseudomonas aeruginosa dan Staphylococcus aureusAbstractTristania subauriculata King has been known by the people of Kelok Sembilan, Payakumbuh as the medicine to cure dermatopathy. It is thought that Tristania subauriculata King contains a bioactive constituent which acts as anti bacteria.To figure the effects of methanol extract of Tristania subauriculata King in holding the growth of Pseudomonas aeruginosa and Staphylococcus aureus,an invitro observation has been done using difusion agar method. The observation was done by measuring the diameter of inhibition area that has been formed.From the observation, it is found that there is inhibition capacity of methanol extract of Tristania subauriculata King 15% b/v in holding the growth ofARTIKEL PENELITIAN38Pseudomonas aeruginosa and Staphylococcus aureus. This inhibition capacity increase on the concentration of 30% b/v, 45% b/v, and the biggest inhibition capacity is on the

  8. 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

  9. Characterization and interstrain transfer of prophage pp3 of Pseudomonas aeruginosa.

    Science.gov (United States)

    Li, Gang; Lu, Shuguang; Shen, Mengyu; Le, Shuai; Shen, Wei; Tan, Yinling; Wang, Jing; Zhao, Xia; Zhao, Yan; Gong, Yali; Yang, Yuhui; Zhu, Hongbin; Hu, Fuquan; Li, Ming

    2017-01-01

    Prophages are major contributors to horizontal gene transfer and drive the evolution and diversification of bacteria. Here, we describe the characterization of a prophage element designated pp3 in the clinical Pseudomonas aeruginosa isolate PA1. pp3 spontaneously excises from the PA1 genome and circularizes at a very high frequency of 25%. pp3 is likely to be a defective prophage due to its inability to form plaques on P. aeruginosa indicator strains, and no phage particles could be detected in PA1 supernatants. The pp3-encoded integrase is essential for excision by mediating site-specific recombination at the 26-bp attachment sequence. Using a filter mating experiment, we demonstrated that pp3 can transfer into P. aeruginosa recipient strains that do not possess this element naturally. Upon transfer, pp3 integrates into the same attachment site as in PA1 and maintains the ability to excise and circularize. Furthermore, pp3 significantly promotes biofilm formation in the recipient. Sequence alignment reveals that the 26-bp attachment site recognized by pp3 is conserved in all P. aeruginosa strains sequenced to date, making it possible that pp3 could be extensively disseminated in P. aeruginosa. This work improves our understanding of the ways in which prophages influence bacterial behavior and evolution.

  10. Electrochemical detection of Pseudomonas aeruginosa in human fluid samples via pyocyanin.

    Science.gov (United States)

    Webster, Thaddaeus A; Sismaet, Hunter J; Conte, Jared L; Chan, I-ping J; Goluch, Edgar D

    2014-10-15

    The ability to quickly detect the presence of pathogenic bacteria in patient samples is of the outmost importance to expedient patient care. Here we report the direct, selective, and sensitive detection of the opportunistic pathogen Pseudomonas aeruginosa, spiked in human whole blood with sodium heparin, urine, sputum, and bronchial lavage samples using unmodified, disposable carbon electrode sensors that detect the presence of pyocyanin, a virulence factor that is unique to this species. Square wave voltammetry scans of biological fluids from healthy individuals spiked with P. aeruginosa showed a clear pyocyanin response within one day of culturing at 37°C. Scans of supernatants taken from cultures of P. aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermis, and Bacillus cereus taken over a span of three days in the potential range from -0.5 to 0 V vs. an Ag/AgCl reference showed no electrochemically detectable molecules with the exception of P. aeruginosa. The results indicate the potential to sensitively and selectively determine the presence of P. aeruginosa in human samples via the electrochemical detection of pyocyanin in less than 5 min, without any sample preparation or separation steps. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Raloxifene attenuates Pseudomonas aeruginosa pyocyanin production and virulence.

    Science.gov (United States)

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

    2012-09-01

    There has been growing interest in disrupting bacterial virulence mechanisms as a form of infectious disease control through the use of 'anti-infective' drugs. Pseudomonas aeruginosa is an opportunistic pathogen noted for its intrinsic antibiotic resistance that causes serious infections requiring new therapeutic options. In this study, an analysis of the P. aeruginosa PAO1 deduced proteome was performed to identify pathogen-associated proteins. A computational screening approach was then used to discover drug repurposing opportunities, i.e. identifying approved drugs that bind and potentially disrupt the pathogen-associated protein targets. The selective oestrogen receptor modulator raloxifene, a drug currently used in the prevention of osteoporosis and/or invasive breast cancer in post-menopausal women, was predicted from this screen to bind P. aeruginosa PhzB2. PhzB2 is involved in production of the blue pigment pyocyanin produced via the phenazine biosynthesis pathway. Pyocyanin is toxic to eukaryotic cells and has been shown to play a role in infection in a mouse model, making it an attractive target for anti-infective drug discovery. Raloxifene was found to strongly attenuate P. aeruginosa virulence in a Caenorhabditis elegans model of infection. Treatment of P. aeruginosa wild-type strains PAO1 and PA14 with raloxifene resulted in a dose-dependent reduction in pyocyanin production in vitro; pyocyanin production and virulence were also reduced for a phzB2 insertion mutant. These results suggest that raloxifene may be suitable for further development as a therapeutic for P. aeruginosa infection and that such already approved drugs may be computationally screened and potentially repurposed as novel anti-infective/anti-virulence agents. Copyright © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  12. Prevalence and analysis of Pseudomonas aeruginosa in chinchillas

    Directory of Open Access Journals (Sweden)

    Aoyama Naoki

    2010-11-01

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

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

    Science.gov (United States)

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

    2017-08-01

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

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

    NARCIS (Netherlands)

    Schijven JF; Havelaar AH

    1989-01-01

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

  15. Revamping the role of biofilm regulating operons in device-associated Staphylococci and Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Pradeep P Halebeedu

    2014-01-01

    Full Text Available Extensive use of indwelling devices in modern medicine has revoked higher incidence of device associated infections and most of these devices provide an ideal surface for microbial attachment to form strong biofilms. These obnoxious biofilms are responsible for persistent infections, longer hospitalization and high mortality rate. Gene regulations in bacteria play a significant role in survival, colonization and pathogenesis. Operons being a part of gene regulatory network favour cell colonization and biofilm formation in various pathogens. This review explains the functional role of various operons in biofilm expression and regulation observed in device-associated pathogens such as Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa.

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  17. Two Isoforms of Clp Peptidase in Pseudomonas aeruginosa Control Distinct Aspects of Cellular Physiology

    OpenAIRE

    Hall, Branwen M.; Breidenstein, Elena B. M.; de la Fuente-Núñez, César; Reffuveille, Fany; Mawla, Gina D.; Hancock, Robert E. W.; Baker, Tania A.

    2017-01-01

    Caseinolytic peptidases (ClpPs) regulate diverse aspects of cellular physiology in bacteria. Some species have multiple ClpPs, including the opportunistic pathogen Pseudomonas aeruginosa, in which there is an archetypical isoform, ClpP1, and a second isoform, ClpP2, about which little is known. Here, we use phenotypic assays to investigate the biological roles of ClpP1 and ClpP2 and biochemical assays to characterize purified ClpP1, ClpP2, ClpX, and ClpA. Interestingly, ClpP1 and ClpP2 have d...

  18. Dynamic laser speckle to detect motile bacterial response of Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Sendra, H [Laboratorio de Laser. Facultad de Ingenieria. Universidad Nacional de Mar del Plata, Juan B. Justo 4302. (7600) Mar del Plata (Argentina); Murialdo, S [Grupo de Ingenieria BioquImica. Departamento de Quimica. Facultad de Ingenieria. Universidad Nacional de Mar del Plata, Juan B. Justo 4302. (7600) Mar del Plata (Argentina); Passoni, L [Laboratorio de BioingenierIa. Facultad de Ingenieria. Universidad Nacional de Mar del Plata, Juan B. Justo 4302. (7600) Mar del Plata (Argentina)

    2007-11-15

    This proposal deals with the technique for detection of motile response of Pseudomonas aeruginosa using dynamic laser speckle or biospeckle as an alternative method. The study of bacterial displacement plays an essential role in biocatalysts processes and biodegradation. Hence, some biodegrading enzymes are benign catalytic that could be used for the production of industrially useful compounds as well as in wastewater treatments. This work presents an experimental set up and a computational process using frame sequences of dynamic laser speckle as a novel application. The objective was the detection of different levels of motility in bacteria. The encouraging results were achieved through a direct and non invasive observation method of the phenomenon.

  19. Novel mouse model of chronic Pseudomonas aeruginosa lung infection mimicking cystic fibrosis

    DEFF Research Database (Denmark)

    Hoffmann, Nadine; Rasmussen, Thomas Bovbjerg; Jensen, Peter Østrup

    2005-01-01

    Pseudomonas aeruginosa causes a chronic infection in the lungs of cystic fibrosis (CF) patients by establishing an alginate-containing biofilm. The infection has been studied in several animal models; however, most of the models required artificial embedding of the bacteria. We present here a new...... pulmonary mouse model without artificial embedding. The model is based on a stable mucoid CF sputum isolate (NH57388A) with hyperproduction of alginate due to a deletion in mucA and functional N-acylhomoserine lactone (AHL)-based quorum-sensing systems. Chronic lung infection could be established in both CF...

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

    Science.gov (United States)

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

    2016-05-24

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

  1. Mass Spectrometry Analysis of Pseudomonas aeruginosa Treated with Azithromycin

    Science.gov (United States)

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

    2015-06-01

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

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

    Science.gov (United States)

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

    2017-01-13

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

  3. Hemorrhagic pneumonia in mink caused by Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Salomonsen, Charlotte Mark

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

  4. Plasmid profile as fingerprinting of typing Pseudomonas aeruginosa

    OpenAIRE

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Shabana Bharathi

    2014-01-01

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

  6. Comparative genomics and biological characterization of sequential Pseudomonas aeruginosa isolates from persistent airways infection.

    Science.gov (United States)

    Bianconi, Irene; Jeukens, Julie; Freschi, Luca; Alcalá-Franco, Beatriz; Facchini, Marcella; Boyle, Brian; Molinaro, Antonio; Kukavica-Ibrulj, Irena; Tümmler, Burkhard; Levesque, Roger C; Bragonzi, Alessandra

    2015-12-29

    Pseudomonas aeruginosa establishes life-long chronic airway infections in cystic fibrosis (CF) patients. As the disease progresses, P. aeruginosa pathoadaptive variants are distinguished from the initially acquired strain. However, the genetic basis and the biology of host-bacteria interactions leading to a persistent lifestyle of P. aeruginosa are not understood. As a model system to study long term and persistent CF infections, the P. aeruginosa RP73, isolated 16.9 years after the onset of airways colonization from a CF patient, was investigated. Comparisons with strains RP1, isolated at the onset of the colonization, and clonal RP45, isolated 7 years before RP73 were carried out to better characterize genomic evolution of P. aeruginosa in the context of CF pathogenicity. Virulence assessments in disease animal model, genome sequencing and comparative genomics analysis were performed for clinical RP73, RP45, RP1 and prototype strains. In murine model, RP73 showed lower lethality and a remarkable capability of long-term persistence in chronic airways infection when compared to other strains. Pathological analysis of murine lungs confirmed advanced chronic pulmonary disease, inflammation and mucus secretory cells hyperplasia. Genomic analysis predicted twelve genomic islands in the RP73 genome, some of which distinguished RP73 from other prototype strains and corresponded to regions of genome plasticity. Further, comparative genomic analyses with sequential RP isolates showed signatures of pathoadaptive mutations in virulence factors potentially linked to the development of chronic infections in CF. The genome plasticity of P. aeruginosa particularly in the RP73 strain strongly indicated that these alterations may form the genetic basis defining host-bacteria interactions leading to a persistent lifestyle in human lungs.

  7. Activity of Bacteriophages in Removing Biofilms of Pseudomonas aeruginosa Isolates from Chronic Rhinosinusitis Patients

    Directory of Open Access Journals (Sweden)

    Stephanie A. Fong

    2017-09-01

    Full Text Available Introduction:Pseudomonas aeruginosa infections are prevalent amongst chronic rhinosinusitis (CRS sufferers. Many P. aeruginosa strains form biofilms, leading to treatment failure. Lytic bacteriophages (phages are viruses that infect, replicate within, and lyse bacteria, causing bacterial death.Aim: To assess the activity of a phage cocktail in eradicating biofilms of ex vivo P.aeruginosa isolates from CRS patients.Methods: P. aeruginosa isolates from CRS patients with and without cystic fibrosis (CF across three continents were multi-locus sequence typed and tested for antibiotic resistance. Biofilms grown in vitro were treated with a cocktail of four phages (CT-PA. Biofilm biomass was measured after 24 and 48 h, using a crystal violet assay. Phage titrations were performed to confirm replication of the phages. A linear mixed effects model was applied to assess the effects of treatment, time, CF status, and multidrug resistance on the biomass of the biofilm.Results: The isolates included 44 strain types. CT-PA treatment significantly reduced biofilm biomass at both 24 and 48 h post-treatment (p < 0.0001, regardless of CF status or antibiotic resistance. Biomass was decreased by a median of 76% at 48 h. Decrease in biofilm was accompanied by a rise in phage titres for all except one strain.Conclusion: A single dose of phages is able to significantly reduce biofilms formed in vitro by a range of P.aeruginosa isolates from CRS patients. This represents an exciting potential and novel targeted treatment for P. aeruginosa biofilm infections and multidrug resistant bacteria.

  8. The anti-cancerous drug doxorubicin decreases the c-di-GMP content in Pseudomonas aeruginosa but promotes biofilm formation

    DEFF Research Database (Denmark)

    Groizeleau, Julie; Rybtke, Morten; Andersen, Jens Bo

    2016-01-01

    for their potential c-di-GMP-lowering effect using a recently developed c-di-GMP biosensor strain. Our screen identified the anti-cancerous drug doxorubicin as a potent c-di-GMP inhibitor. In addition, the drug decreased the transcription of many biofilm-related genes. However, despite its effect on the c...... formation in many clinically relevant bacteria. It is hypothesized that drugs lowering the intracellular level of c-di-GMP will force biofilm bacteria into a more treatable planktonic lifestyle. To identify compounds capable of lowering c-di-GMP levels in Pseudomonas aeruginosa, we screened 5000 compounds......-di-GMP content in P. aeruginosa, doxorubicin was unable to inhibit biofilm formation or disperse established biofilms. On the contrary, the drug was found to promote P. aeruginosa biofilm formation, possibly through release of extracellular DNA from a subpopulation of killed bacteria. Our findings emphasize...

  9. Toxicity of Phenol and Salt on the Phenol-Degrading Pseudomonas aeruginosa Bacterium

    Directory of Open Access Journals (Sweden)

    Samaei

    2016-08-01

    Full Text Available Background Phenolic compounds, phenol and phenol derivatives are environmental contaminants in some industrial effluents. Entrance of such substances into the environment causes severe environmental pollution, especially pollution of water resources. Biological treatment is a method that uses the potential of microorganisms to clean up contaminated environments. Among microorganisms, bacteria play an important role in treating wastewater contaminated with phenol. Objectives This study aimed to examine the effects of Pseudomonas aeruginosa on degradation of phenol in wastewater contaminated with this pollutant. Methods In this method, the growth rate of P. aeruginosa bacteria was investigated using different concentrations of salt and phenol. This is an experimental study conducted as a pilot in a batch reactor with different concentrations of phenol (25, 50, 100, 150, 300 and 600 mg L-1 and salt (0%, 0.5%, 1%, 2.5% and 5% during 9, 12 and 15 hours. During three days, from 5 experimental and 3 control samples, 18 samples were taken a day forming a sample size of 54 samples for each phenol concentration. Given the number of phenol concentrations (n = 6, a total of 324 samples were analyzed using a spectrophotometer at a wavelength of 600 nm. Results The phenol concentration of 600 mg L-1 was toxic for P. aeruginosa. However, at a certain concentration, it acts as a carbon source for P. aeruginosa. During investigations, it was found that increasing the concentration of phenol increases the rate of bacteria growth. The highest bacteria growth rate occurred was at the salt concentration of zero and phenol concentration of 600 mg L-1. Conclusions The findings of the current study indicate that at high concentrations of salt, the growth of bacteria reduces so that it stops at a concentration of 50 mg L-1 (5%. Thus, the bacterium is halotolerant or halophilic. With an increase in phenol concentration, the growth rate increased. Phenol toxicity appears

  10. Pseudomonas aeruginosa mastitis in two goats associated with an essential oil-based teat dip.

    Science.gov (United States)

    Kelly, E Jane; Wilson, David J

    2016-11-01

    Pseudomonas aeruginosa is an opportunistic pathogen that has been associated with mastitis in dairy animals, including goats. Often, the environmental sources of the bacteria are water-related (such as hoses and muddy pastures). Mastitis attributable to P. aeruginosa was identified in 2 goats in a small herd. Efforts were made to identify environmental sources of the pathogen. Multiple samples from the goats' environment were cultured, including water from the trough, bedding, the hose used to wash udders, and the teat dip and teat dip containers. The bacterium was isolated from the teat dip and the teat dip container. The teat dip consisted of water, liquid soap, and several drops of essential oils (including tea tree, lavender, and peppermint). This case illustrates a potential problem that may arise as a result of the use of unconventional ingredients in teat dips. The use of alternative products by goat producers is likely to increase in the future. © 2016 The Author(s).

  11. Sugar administration is an effective adjunctive therapy in the treatment of Pseudomonas aeruginosa pneumonia

    Science.gov (United States)

    Bucior, Iwona; Abbott, Jason; Song, Yuanlin; Matthay, Michael A.

    2013-01-01

    Treatment of acute and chronic pulmonary infections caused by opportunistic pathogen Pseudomonas aeruginosa is limited by the increasing frequency of multidrug bacterial resistance. Here, we describe a novel adjunctive therapy in which administration of a mix of simple sugars—mannose, fucose, and galactose—inhibits bacterial attachment, limits lung damage, and potentiates conventional antibiotic therapy. The sugar mixture inhibits adhesion of nonmucoid and mucoid P. aeruginosa strains to bronchial epithelial cells in vitro. In a murine model of acute pneumonia, treatment with the sugar mixture alone diminishes lung damage, bacterial dissemination to the subpleural alveoli, and neutrophil- and IL-8-driven inflammatory responses. Remarkably, the sugars act synergistically with anti-Pseudomonas antibiotics, including β-lactams and quinolones, to further reduce bacterial lung colonization and damage. To probe the mechanism, we examined the effects of sugars in the presence or absence of antibiotics during growth in liquid culture and in an ex vivo infection model utilizing freshly dissected mouse tracheas and lungs. We demonstrate that the sugar mixture induces rapid but reversible formation of bacterial clusters that exhibited enhanced susceptibility to antibiotics compared with individual bacteria. Our findings reveal that sugar inhalation, an inexpensive and safe therapeutic, could be used in combination with conventional antibiotic therapy to more effectively treat P. aeruginosa lung infections. PMID:23792737

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

    NARCIS (Netherlands)

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

    2012-01-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

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

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    LENUS (Irish Health Repository)

    Linnane, Barry

    2015-10-01

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

  18. Pseudomonas aeruginosa induces pigment production and enhances virulence in a white phenotypic variant of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Antonic V

    2013-11-01

    Full Text Available Vlado Antonic,1–3 Alexander Stojadinovic,3–5 Binxue Zhang,1–3 Mina J Izadjoo,1–3,5 Mohammad Alavi1–3 1Henry M Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA; 2Diagnostic and Translational Research Center, Gaithersburg, MD, USA; 3Combat Wound Initiative Program, Bethesda, MD, USA; 4Walter Reed National Military Medical Center, Bethesda, MD, USA; 5Uniformed Services University of the Health Sciences, Bethesda, MD, USA Abstract: Staphyloxanthin is a virulence factor which protects Staphylococcus aureus in stress conditions. We isolated two pigment variants of S. aureus and one strain of Pseudomonas aeruginosa from a single wound infection. S. aureus variants displayed white and yellow colony phenotypes. The sequence of the operons for staphyloxanthin synthesis indicated that coding and promoter regions were identical between the two pigment variants. Quorum sensing controls pigment synthesis in some bacteria. It is also shown that P. aeruginosa quorum-sensing molecules affect S. aureus transcription. We explored whether the co-infecting P. aeruginosa can affect pigment production in the white S. aureus variant. In co-culture experiments between the white variants and a selected number of Gram-positive and Gram-negative bacteria, only P. aeruginosa induced pigment production in the white variant. Gene expression analysis of the white variant did not indicate upregulation of the crtM and other genes known to be involved in pigment production (sigB, sarA, farnesyl pyrophosphate synthase gene [FPP-synthase], hfq. In contrast, transcription of the catalase gene was significantly upregulated after co-culture. P. aeruginosa-induced pigment synthesis and catalase upregulation correlated with increased resistance to polymyxin B, hydrogen peroxide, and the intracellular environment of macrophages. Our data indicate the presence of silent but functional staphyloxanthin synthesis machinery in a white phenotypic variant

  19. A Mig-14-like protein (PA5003) affects antimicrobial peptide recognition in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Jochumsen, Nicholas; Liu, Yang; Molin, Søren

    2011-01-01

    The evolution of antibiotic resistance in pathogenic bacteria is a growing global health problem which is gradually making the treatment of infectious diseases less efficient. Antimicrobial peptides are small charged molecules found in organisms from the complete phylogenetic spectrum. The peptides...... are attractive candidates for novel drug development due to their activity against bacteria that are resistant to conventional antibiotics, and reports of peptide resistance are rare in the clinical setting. Paradoxically, many clinically relevant bacteria have mechanisms that can recognize and respond...... to the presence of cationic antimicrobial peptides (CAMPs) in the environment by changing the properties of the microbial surface thereby increasing the tolerance of the microbes towards the peptides. In Pseudomonas aeruginosa an essential component of this inducible tolerance mechanism is the lipopolysaccharide...

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

    Directory of Open Access Journals (Sweden)

    R. Satheeskumar

    2013-10-01

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

  1. Evaluation of biofilm production by Pseudomonas aeruginosa from canine ears and the impact of biofilm on antimicrobial susceptibility in vitro.

    Science.gov (United States)

    Pye, Charlotte C; Yu, Anthony A; Weese, J Scott

    2013-08-01

    Pseudomonas aeruginosa is a common cause of canine otitis; P. aeruginosa biofilm formation has been documented in human medicine, but the role of biofilms in canine disease is not well documented. Bacteria within biofilms can be more resistant to antibiotics compared with their planktonic form; therefore, understanding the biofilm-forming capacity of isolates and their susceptibility to antimicrobials is important when developing treatment regimens. To evaluate the biofilm-forming capacity of canine otic isolates of P. aeruginosa and to compare the minimal inhibitory concentration (MIC) of the planktonic versus biofilm-embedded bacteria. Biofilm-forming ability was assessed using a microtitre plate assay. Broth microdilution was used to assess the MICs of neomycin, polymyxin B, enrofloxacin and gentamicin for the planktonic and biofilm-embedded bacteria. Eighty-three isolates from dogs with otitis were tested; 33 (40%) were classified as biofilm producers. Biofilm MICs for polymyxin B, neomycin, gentamicin and enrofloxacin were significantly higher than for the planktonic form (P otitis isolates of P. aeruginosa is common and may play a role in the pathogenesis of disease. The MICs for biofilm-embedded bacteria differ from their planktonic counterparts, potentially leading to a lack of response to treatment. If polymyxin B, gentamicin, neomycin or enrofloxacin is to be used for topical treatment of a Pseudomonas otitis, the concentration of the medication should be increased, in particular if addressing chronic otitis, because biofilms may have developed. © 2013 The Authors. Veterinary Dermatology © 2013 ESVD and ACVD.

  2. Combination antimicrobial susceptibility testing for acute exacerbations in chronic infection of Pseudomonas aeruginosa in cystic fibrosis.

    Science.gov (United States)

    Waters, Valerie; Ratjen, Felix

    2017-06-19

    eligible for inclusion in the review. This study prospectively assessed whether the use of multiple combination bactericidal antibiotic testing improved clinical outcomes in participants with acute pulmonary exacerbations of cystic fibrosis who were infected with multiresistant bacteria. A total of 132 participants were randomised in the study. The study investigators provided data specific to the 82 participants who were only infected with Pseudomonas aeruginosa for their primary outcome of time until next pulmonary exacerbation. For participants specifically infected with only Pseudomonas aeruginosa, the hazard ratio of a subsequent exacerbation was 0.82, favouring the control group (95% confidence interval 0.44 to 1.51) (P = 0.52). No further data for any of this review's outcomes specific to participants infected with Pseudomonas aeruginosa were available. The risk of bias for the included study was deemed to be low. The quality of the evidence was moderate for the only outcome providing data solely for individuals with infection due to Pseudomonas aeruginosa. For other outcomes, we were unable to judge the quality of the evidence as no data were available for the relevant subset of participants. The current evidence, limited to one study, shows that there is insufficient evidence to determine effect of choosing antibiotics based on combination antimicrobial susceptibility testing compared to choosing antibiotics based on conventional antimicrobial susceptibility testing in the treatment of acute pulmonary exacerbations in people with cystic fibrosis with chronic Pseudomonas aeruginosa infection. A large international and multicentre study is needed to further investigate this issue.The only study included in the review was published in 2005, and we have not identified any further relevant studies up to March 2017. We therefore do not plan to update this review until new studies are published.

  3. PA3297 Counteracts Antimicrobial Effects of Azithromycin in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Hao eTan

    2016-03-01

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

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

    Science.gov (United States)

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

    2017-10-01

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

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

    Science.gov (United States)

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

    2014-02-01

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

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

    Science.gov (United States)

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

    2016-02-24

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

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

    Science.gov (United States)

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

    2017-03-01

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

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

    Science.gov (United States)

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

    2017-12-21

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

  9. Identification of novel members of the bacterial azoreductase family in Pseudomonas aeruginosa.

    Science.gov (United States)

    Crescente, Vincenzo; Holland, Sinead M; Kashyap, Sapna; Polycarpou, Elena; Sim, Edith; Ryan, Ali

    2016-03-01

    Azoreductases are a family of diverse enzymes found in many pathogenic bacteria as well as distant homologues being present in eukarya. In addition to having azoreductase activity, these enzymes are also suggested to have NAD(P)H quinone oxidoreductase (NQO) activity which leads to a proposed role in plant pathogenesis. Azoreductases have also been suggested to play a role in the mammalian pathogenesis of Pseudomonas aeruginosa. In view of the importance of P. aeruginosa as a pathogen, we therefore characterized recombinant enzymes following expression of a group of putative azoreductase genes from P. aeruginosa expressed in Escherichia coli. The enzymes include members of the arsenic-resistance protein H (ArsH), tryptophan repressor-binding protein A (WrbA), modulator of drug activity B (MdaB) and YieF families. The ArsH, MdaB and YieF family members all show azoreductase and NQO activities. In contrast, WrbA is the first enzyme to show NQO activity but does not reduce any of the 11 azo compounds tested under a wide range of conditions. These studies will allow further investigation of the possible role of these enzymes in the pathogenesis of P. aeruginosa. © 2016 Authors; published by Portland Press Limited.

  10. Pseudomonas aeruginosa contamination of mouth swabs during production causing a major outbreak

    Directory of Open Access Journals (Sweden)

    Lassen Jørgen

    2007-03-01

    Full Text Available Abstract Background In 2002 we investigated an outbreak comprising 231 patients in Norway, caused by Pseudomonas aeruginosa and linked to the use of contaminated mouth swabs called Dent-O-Sept. Here we describe the extent of contamination of the swabs, and identify critical points in the production process that made the contamination possible, in order to prevent future outbreaks. Methods Environmental investigation with microbiological examination of production, ingredients and product, molecular typing of bacteria and a system audit of production. Results Of the 1565 swabs examined from 149 different production batches the outbreak strain of P. aeruginosa was detected in 76 swabs from 12 batches produced in 2001 and 2002. In total more than 250 swabs were contaminated with one or more microbial species. P. aeruginosa was detected from different spots along the production line. The audit revealed serious breeches of production regulations. Health care institutions reported non-proper use of the swabs and weaknesses in their purchasing systems. Conclusion Biofilm formation in the wet part of the production is the most plausible explanation for the continuous contamination of the swabs with P. aeruginosa over a period of at least 30 weeks. When not abiding to production regulations fatal consequences for the users may ensue. For the most vulnerable patient groups only documented quality-controlled, high-level disinfected products and items should be used in the oropharynx.

  11. POTENSI PSEUDOMONAS AERUGINOSA SEBAGAI AGENS BIOKONTROL TERHADAP SCLEROTIUM ROLFSII SACC. DAN BIOSTIMULAN PADA TANAMAN KEDELAI

    Directory of Open Access Journals (Sweden)

    KHAMDAN KHALIMI

    2012-11-01

    Full Text Available Potential of Pseudomonas aeruginosa as Biological Control Agents against Sclerotium rolfsii Sacc. and Biological Stimulants on Soybean Plant. The objectives of this experiment were conducted to evaluate the effectiveness ofP. aeruginosa as an agent of biological control and biological stimulants. P. aeruginosawere tested for antagonistic activity against Sclerotium rolfsii Sacc. The test for antagonistic activity by bacteria was done through side by side culture. Soybean seeds that will be used in the rhizobacteria treatment were soaked in rhizobacteria suspension for 15 minutes. For wihout the treatment, seeds soaked with sterile water instead of rhizobacteria suspension. Results of this experiment,P. aeruginosa showed strong inhibitory activity againstS. rolfsii Sacc. on PDA medium. Percentage of inhibitory activity was 94,4%. Application of P. aeruginosa significantly increased the plant growth. The maximum plant hight, the maximum number of leaves, fresh and dry weights of root, fresh and dry weights of shoot, and chlorophyll content on treated plants significantly higher than those of un-treated control plants according to the Duncan’s multiple range test (P<0.05%. These results suggested that application of rhizobacteria could promote the plant growth and increase the yield.

  12. Pyocyanin alters redox homeostasis and carbon flux through central metabolic pathways in Pseudomonas aeruginosa PA14.

    Science.gov (United States)

    Price-Whelan, Alexa; Dietrich, Lars E P; Newman, Dianne K

    2007-09-01

    The opportunistic pathogen Pseudomonas aeruginosa produces colorful, redox-active antibiotics called phenazines. Excretion of pyocyanin, the best-studied natural phenazine, is responsible for the bluish tint of sputum and pus associated with P. aeruginosa infections in humans. Although the toxicity of pyocyanin for other bacteria, as well as its role in eukaryotic infection, has been studied extensively, the physiological relevance of pyocyanin metabolism for the producing organism is not well understood. Pyocyanin reduction by P. aeruginosa PA14 is readily observed in standing liquid cultures that have consumed all of the oxygen in the medium. We investigated the physiological consequences of pyocyanin reduction by assaying intracellular concentrations of NADH and NAD+ in the wild-type strain and a mutant defective in phenazine production. We found that the mutant accumulated more NADH in stationary phase than the wild type. This increased accumulation correlated with a decrease in oxygen availability and was relieved by the addition of nitrate. Pyocyanin addition to a phenazine-null mutant also decreased intracellular NADH levels, suggesting that pyocyanin reduction facilitates redox balancing in the absence of other electron acceptors. Analysis of extracellular organic acids revealed that pyocyanin stimulated stationary-phase pyruvate excretion in P. aeruginosa PA14, indicating that pyocyanin may also influence the intracellular redox state by decreasing carbon flux through central metabolic pathways.

  13. Pseudomonas aeruginosa alkaline protease blocks complement activation via the classical and lectin pathways.

    Science.gov (United States)

    Laarman, Alexander J; Bardoel, Bart W; Ruyken, Maartje; Fernie, Job; Milder, Fin J; van Strijp, Jos A G; Rooijakkers, Suzan H M

    2012-01-01

    The complement system rapidly detects and kills Gram-negative bacteria and supports bacterial killing by phagocytes. However, bacterial pathogens exploit several strategies to evade detection by the complement system. The alkaline protease (AprA) of Pseudomonas aeruginosa has been associated with bacterial virulence and is known to interfere with complement-mediated lysis of erythrocytes, but its exact role in bacterial complement escape is unknown. In this study, we analyzed how AprA interferes with complement activation and whether it could block complement-dependent neutrophil functions. We found that AprA potently blocked phagocytosis and killing of Pseudomonas by human neutrophils. Furthermore, AprA inhibited opsonization of bacteria with C3b and the formation of the chemotactic agent C5a. AprA specifically blocked C3b deposition via the classical and lectin pathways, whereas the alternative pathway was not affected. Serum degradation assays revealed that AprA degrades both human C1s and C2. However, repletion assays demonstrated that the mechanism of action for complement inhibition is cleavage of C2. In summary, we showed that P. aeruginosa AprA interferes with classical and lectin pathway-mediated complement activation via cleavage of C2.

  14. Chlorine disinfection of Pseudomonas aeruginosa, total coliforms, Escherichia coli and Enterococcus faecalis: revisiting reclaimed water regulations.

    Science.gov (United States)

    Coronel-Olivares, Claudia; Reyes-Gómez, Lidia María; Hernández-Muñoz, Aurelio; Martínez-Falcón, Ana Paola; Vázquez-Rodríguez, Gabriela A; Iturbe, Ulises

    2011-01-01

    Pathogenic organisms can be transmitted orally through drinking water or through skin and mucosae by both direct and indirect contact, and their presence in water thus has a negative impact on public health. In wastewater treatment plants (WWTP), water is disinfected to inactivate pathogens. The quantification of several microbial indicators in aquatic systems is required to estimate the biological quality of such systems. So far, coliform bacteria have been used as traditional indicators world-wide. This study has assessed the resistance of total coliforms, Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis to three dosages of sodium hypochlorite (NaClO) at two exposure times. The bacteria were isolated from secondary effluents of a WWTP located in Hidalgo, Mexico. The results show that the number of colony-forming units of all studied bacterial types decreased when both the NaClO concentration and exposure times increased. However, they were not eliminated. The inclusion of the species Pseudomonas aeruginosa in regulations for treated wastewater quality as a new indicator is highly recommended due to its importance as an opportunistic pathogen. The detection of this species along with the traditional organisms could be particulary significant for reclaimed water to be used with direct human contact.

  15. The synergistic effect of visible light and gentamycin on Pseudomona aeruginosa microorganisms.

    Science.gov (United States)

    Reznick, Yana; Banin, Ehud; Lipovsky, Anat; Lubart, Rachel; Polak, Pazit; Zalevsky, Zeev

    2013-07-02

    Recently there were several publications on the bactericidal effect of visible light, most of them claiming that blue part of the spectrum (400 nm-500 nm) is responsible for killing various pathogens(1-5). The phototoxic effect of blue light was suggested to be a result of light-induced reactive oxygen species (ROS) formation by endogenous bacterial photosensitizers which mostly absorb light in the blue region(4,6,7). There are also reports of biocidal effect of red and near infra red(8) as well as green light(9). In the present study, we developed a method that allowed us to characterize the effect of high power green (wavelength of 532 nm) continuous (CW) and pulsed Q-switched (Q-S) light on Pseudomonas aeruginosa. Using this method we also studied the effect of green light combined with antibiotic treatment (gentamycin) on the bacteria viability. P. aeruginosa is a common noscomial opportunistic pathogen causing various diseases. The strain is fairly resistant to various antibiotics and contains many predicted AcrB/Mex-type RND multidrug efflux systems(10). The method utilized free-living stationary phase Gram-negative bacteria (P. aeruginosa strain PAO1), grown in Luria Broth (LB) medium exposed to Q-switched and/or CW lasers with and without the addition of the antibiotic gentamycin. Cell viability was determined at different time points. The obtained results showed that laser treatment alone did not reduce cell viability compared to untreated control and that gentamycin treatment alone only resulted in a 0.5 log reduction in the viable count for P. aeruginosa. The combined laser and gentamycin treatment, however, resulted in a synergistic effect and the viability of P. aeruginosa was reduced by 8 log's. The proposed method can further be implemented via the development of catheter like device capable of injecting an antibiotic solution into the infected organ while simultaneously illuminating the area with light.

  16. Spontaneous Nosocomial Pseudomonas aeruginosa Meningitis Presenting as Trismus

    Directory of Open Access Journals (Sweden)

    C. J. Parr

    2017-01-01

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

  17. Detection of Chloramphenicol Resistance Genes (cat in Clinical Isolates of Pseudomonas aeruginosa with Polymerase Chain Reaction Method

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    Tiana Milanda

    2014-12-01

    Full Text Available Pseudomonas aeruginosa is an opportunistic Gram negative bacteria, which may cause infection in eyes, ears, skin, bones, central nervous system, gastrointestinal tract, circulatory system, heart, respiratory system, and urinary tract. Recently, chloramphenicol is no longer used as the main option of the therapy due of its resistance case. The aim of this research was to detect the presence of gene which is responsible to chloramphenicol resistance in clinical isolates of P.aeruginosa. These bacteria isolated from pus of external otitis patients in Hasan Sadikin Hospital in Bandung City. Polymerase Chain Reaction (PCR method (colony-PCR and DNA-PCR were performed to detect this resistance gene. Electropherogram from PCR products showed that the chloramphenicol resistance in clinical isolates of P. aeruginosa was caused by cat gene (317 bp. Based on this research, cat gene may be used to detect the chloramphenicol resistance in patients with external ostitis.

  18. Effects of Chlorine Stress on Pseudomonas aeruginosa Biofilm and Analysis of Related Gene Expressions.

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    Kekeç, Özge; Gökalsın, Barış; Karaltı, İskender; Kayhan, Figen Esin; Sesal, Nüzhet Cenk

    2016-08-01

    Chlorine is deployed worldwide to clean waters and prevent water-originated illnesses. However, chlorine has a limited disinfection capacity against biofilms. Microorganisms form biofilms to protect themselves from biological threats such as disinfectant chemicals. Pseudomonas aeruginosa is an opportunistic pathogen and its biofilm form attaches to surfaces, living buried into exopolysaccharides, can be present in all watery environments including tap water and drinking water. This research aimed to study the biofilm trigger mechanism of the opportunistic pathogen P. aeruginosa PAO1 strain, which is known to form biofilm in water supply systems and human body, under chlorine stress levels. In addition to biofilm staining, certain genes that are relevant to the stress condition were selected for gene expression analysis. The bacteria cultures were grown under chlorine stress with concentrations of 0.5, 0.7 and 1 mg/l. Six gene regions were determined related to biofilm and stress response: rpoS, bifA, migA, katB, soxR, and algC. Biofilm formation was analyzed by basic fuchsin staining, and gene expressions were quantified by quantitative real-time PCR. According to the results, highest biofilm production was observed in P. aeruginosa PAO1 wild strain under no stress conditions. Higher biofilm amounts were observed for bacteria under 0.5 and 0.7 mg/l chlorine stress compared to 1 mg/l chlorine stress.

  19. A functional type I topoisomerase from Pseudomonas aeruginosa

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    Roper Benjamin J

    2009-03-01

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

  20. Comparison of Neutrophil Apoptosis by the Pseudomonas Aeruginosa Exotoxins between Healthy Individuals and Term Infants

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    Soheila Khazaei

    2013-04-01

    Full Text Available Background: Pseudomonas aeruginosa may be colonized in different human tissues and result in some infections potentially. Thus, considering that these bacteria are resistance to most of the current antibiotics, an examination on pathogenesis mechanisms of such bacteria can be effective in controlling the infections developed by it.Materials and Methods: In this project, among 40 blood samples (20 healthy persons, 20 infants, an amount of 5 ml (2 ml in the infants heparinized blood was collected form each and then neutrophils were isolated by a standard method and were counted by neubauer lam. After culturing Pseudomonas bacteria in broth medium, some tubes with densities of 1, 2, 3 and 4 McFarland were prepared and the bacteria were isolated by centrifuge method with 3000rpm for 10 minutes and then its exotoxin were exposed to neutrophils of the groups under study. The effect of time and the bacteria count on the amount of the secreted toxin and in adjacency to neutrophils was measured.Results: There were 11 men and 9 women in the health group and the infants group consisted of 12 boys and 8 girls. Death cell percentage of neutrophils was 100% in the health group and 8.90% in the infants group. Percentage of bacterial growth in the medium 1 and 2 McFarland was zero; in the medium 3 McFarland, it was 12.5% in the healthy group and 1% in the infants group (p<0.10. The average rate of cell death in the minute 15th was different in two groups (68.5% in health group vs. 92.5% in the infants (p<0.0005. Conclusion: This study showed the effect of Pseudomonas bacteria on the development of early cell death in the infants very well. As it was shown, this effect is time-dependent and this cell death (apoptosis is occurred in the infants earlier than health people.

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

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

    2018-03-01

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

  2. Proteomic Response of Pseudomonas aeruginosa PAO1 Adhering to Solid Surfaces

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    Morgan Guilbaud

    2017-08-01

    Full Text Available Pseudomonas aeruginosa is a pathogenic micro-organism responsible for many hospital-acquired infections. It is able to adhere to solid surfaces and develop an immobilized community or so-called biofilm. Many studies have been focusing on the use of specific materials to prevent the formation of these biofilms, but the reactivity of the bacteria in contact to surfaces remains unknown. The aim of this study was to evaluate the impact of the abiotic surface on the physiology of adherent bacteria. Three different materials, stainless steel (SS, glass (G, and polystyrene (PS that were relevant to industrial or medical environments were characterized at the physicochemical level in terms of their hydrophobicity and roughness. We showed that SS was moderately hydrophilic and rough, potentially containing crevices, G was hydrophilic and smooth while PS was hydrophobic and smooth. We further showed that P. aeruginosa cells were more likely able to adhere to SS and G rather than PS surfaces under our experimental conditions. The physiological response of P. aeruginosa when adhering to each of these materials was then evaluated by global proteomic analysis. The abundance of 70 proteins was shown to differ between the materials suggesting that their abundance was modified as a function of the material to which bacteria adhered. Our data lead to enabling the identification of abundance patterns that appeared to be specific to a given surface. Taken together, our data showed that P. aeruginosa is capable of sensing and responding to a surface probably via specific programmes to adapt its physiological response accordingly.

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

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    Jing Shao

    2012-09-01

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

  4. High-Sensitivity Monoclonal Antibodies Specific for Homoserine Lactones Protect Mice from Lethal Pseudomonas aeruginosa Infections

    Science.gov (United States)

    Downham, Christina; Broadbent, Ian; Charlton, Keith; Porter, Andrew J.

    2014-01-01

    A number of bacteria, including pathogens like Pseudomonas aeruginosa, utilize homoserine lactones (HSLs) as quorum sensing (QS) signaling compounds and engage in cell-to-cell communication to coordinate their behavior. Blocking this bacterial communication may be an attractive strategy for infection control as QS takes a central role in P. aeruginosa biology. In this study, immunomodulation of HSL molecules by monoclonal antibodies (MAbs) was used as a novel approach to prevent P. aeruginosa infections and as tools to detect HSLs in bodily fluids as a possible first clue to an undiagnosed Gram-negative infection. Using sheep immunization and recombinant antibody technology, a panel of sheep-mouse chimeric MAbs were generated which recognized HSL compounds with high sensitivity (nanomolar range) and cross-reactivity. These MAbs retained their nanomolar sensitivity in complex matrices and were able to recognize HSLs in P. aeruginosa cultures grown in the presence of urine. In a nematode slow-killing assay, HSL MAbs significantly increased the survival of worms fed on the antibiotic-resistant strain PA058. The therapeutic benefit of these MAbs was further studied using a mouse model of Pseudomonas infection in which groups of mice treated with HSL-2 and HSL-4 MAbs survived, 7 days after pathogen challenge, in significantly greater numbers (83 and 67%, respectively) compared with the control groups. This body of work has provided early proof-of-concept data to demonstrate the potential of HSL-specific, monoclonal antibodies as theranostic clinical leads suitable for the diagnosis, prevention, and treatment of life-threatening bacterial infections. PMID:24185854

  5. Real-Time Monitoring of Pseudomonas Aeruginosa Concentration Using a Novel Electromagnetic Sensors Microfluidic Cell Structure.

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    Blakey, Richard; Nakouti, Ismini; Korostynska, Olga; Mason, Alex; Al-Shamma'a, Ahmed

    2013-12-01

    This study demonstrates an electromagnetic wave-based sensor embedded within a fluidic cell for the purposes of quantifying Pseudomonas aeruginosa in real time, which implies it could be applied for provision of point-of-care diagnostics. The sensors operates through the interaction of the electromagnetic field with the analyte flowing through the fluidic system, and via the sensor head which has a specifically designed planar pattern to maximize the sensor sensitivity for the given bacteria type. The sensor is demonstrated to respond linearly (R(2) = 0.9942) to OD(550) 25 × 10(-3) - 1.0 bacteria concentration through changing resonant frequency and peak quality factor. This innovative approach is expected to contribute to better provision of healthcare services, minimizing the need for hospital visits through real-time point-of-care diagnostics as opposed to lengthy laboratory assays.

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

    Science.gov (United States)

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

    2017-01-13

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

  7. Isolation of the Autoinducer-Quenching Strain that Inhibits LasR in Pseudomonas aeruginosa

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    Lixing Weng

    2014-04-01

    Full Text Available Quorum sensing (QS has been recognized as a general phenomenon in microorganisms and plays an important role in many pathogenic bacteria. In this report, we used the Agrobacterium tumefaciens biosensor strain NT1 to rapidly screen for autoinducer-quenching inhibitors from bacteria. After initial screening 5389 isolates obtained from land and beach soil, 53 putative positive strains were identified. A confirmatory bioassay was carried out after concentrating the putative positive culture supernatant, and 22 strains were confirmed to have anti-LasR activity. Finally, we determined the strain JM2, which could completely inhibit biofilm formation of Pseudomonas aeruginosa PAO1, belonged to the genus Pseudomonas by analysis of 16S rDNA. Partially purified inhibitor factor(s F5 derived from culture supernatants specifically inhibited LasR-controlled elastase and protease in wild type P. aeruginosa PAO1 by 68% and 73%, respectively, without significantly affecting growth; the rhl-controlled pyocyanin and rhamnolipids were inhibited by 54% and 52% in the presence of 100 µg/mL of F5. The swarming motility and biofilm of PAO1 were also inhibited by F5. Real time RT-PCR on samples from 100 µg/mL F5-treated P. aeruginosa showed downregulation of autoinducer synthase (LasRI and rhlI and cognate receptor (lasR and rhlR genes by 50%, 28%, 48%, and 29%, respectively. These results provide compelling evidence that the F5 inhibitor(s interferes with the las system and significantly inhibits biofilm formation.

  8. Nitrite Formation from Hydroxylamine and Oximes by Pseudomonas aeruginosa

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    Amarger, Noelle; Alexander, M.

    1968-01-01

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

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

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    Matthew B Biggs

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

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

    Science.gov (United States)

    Biggs, Matthew B; Papin, Jason A

    2013-01-01

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

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

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    Nazia Jamil

    2008-06-01

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

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

    Science.gov (United States)

    Amarger, N; Alexander, M

    1968-05-01

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

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

    Science.gov (United States)

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

    2017-09-01

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

  14. Porphyromonas gingivalis modulates Pseudomonas aeruginosa-induced apoptosis of respiratory epithelial cells through the STAT3 signaling pathway.

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    Li, Qian; Pan, Chunling; Teng, Di; Lin, Li; Kou, Yurong; Haase, Elaine M; Scannapieco, Frank A; Pan, Yaping

    2014-01-01

    Pseudomonas aeruginosa is an important opportunistic bacterial pathogen, causing infections of respiratory and other organ systems in immunocompromised hosts that may invade and proliferate in mucosal epithelial cells to induce apoptosis. Previous studies suggest that oral bacteria, especially gram-negative periodontal pathogens, may enhance P. aeruginosa invasion into respiratory epithelial cells to augment tissue destruction. In this study, we investigated the effect of the periodontopathogen Porphyromonas gingivalis on P. aeruginosa-induced epithelial cell apoptosis. P. gingivalis invasion transiently inhibited P. aeruginosa-induced apoptosis in respiratory epithelial cells via the signal transducer and activator of transcription 3 (STAT3) signaling pathway. The activated STAT3 up-regulated the downstream anti-apoptotic moleculars survivin and B-cell leukemia-2 (bcl-2). This process was accompanied by down-regulation of pro-apoptosis molecular Bcl-2-associated death promoter (bad) and caspase-3 activity inhibition. In addition, the activation of the STAT3 pathway was affected by P. gingivalis in a dose-dependent manner. Finally, co-invasion of P. aeruginosa and P. gingivalis led to greater cell death compared with P. aeruginosa challenge alone. These results suggest that regulation of P. aeruginosa-induced apoptosis by P. gingivalis contributes to the pathogenesis of respiratory disease. Interference with this process may provide a potential therapeutic strategy for the treatment and prevention of respiratory disease. Copyright © 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

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

    Science.gov (United States)

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

    2013-01-01

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

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

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    Brent Cezairliyan

    2013-01-01

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

  17. Identification of Pseudomonas aeruginosa Phenazines that Kill Caenorhabditis elegans

    Science.gov (United States)

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

    2013-01-01

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

  18. Reactions of Pseudomonas aeruginosa pyocyanin with reduced glutathione.

    Science.gov (United States)

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

    2008-01-01

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

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

    Science.gov (United States)

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

    2009-12-01

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

  20. Resistance of Animal Strains of Pseudomonas aeruginosa to Carbapenems

    Directory of Open Access Journals (Sweden)

    Marisa Haenni

    2017-09-01

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

  1. Effects of growth temperature on polystyrene adhesion of Pseudomonas aeruginosa ATCC 27853 Interferência da temperatura de cultivo na adesão de Pseudomonas aeruginosa ATCC 27853 ao poliestireno

    Directory of Open Access Journals (Sweden)

    Simone Cappello

    2006-09-01

    Full Text Available The importance of avoiding bacterial adhesion to plastic medical devices is recognized. To better understand the interaction between bacteria and surface, we studied the influence of different growth temperatures (15, 30 and 47ºC on the polystyrene adhesion capacity of Pseudomonas aeruginosa ATCC 27853.A importância de evitar a adesão bacteriana aos dispositivos médicos plásticos é reconhecida. Para melhor comprender a interaçao entre bactérias e superfices, este estudo avaliou a influência de diferentes temperaturas de cultivo (15, 30 e 47ºC na adesão da Pseudomonas aeruginosa ATCC 27853 ao poliestireno.

  2. ExoU-induced procoagulant activity in Pseudomonas aeruginosa-infected airway cells.

    Science.gov (United States)

    Plotkowski, M C; Feliciano, L F P; Machado, G B S; Cunha, L G; Freitas, C; Saliba, A M; de Assis, M C

    2008-12-01

    The present study addressed the question whether ExoU, a Pseudomonas aeruginosa toxin with phospholipase A2 (PLA2) activity, may induce airway epithelial cells to overexpress tissue factor (TF) and exhibit a procoagulant phenotype. Cells from the human bronchial epithelial BEAS-2B line were infected with an ExoU-producing P. aeruginosa strain, pre-treated or not with the cytosolic PLA2 inhibitor methylarachidonyl fluorophosphate (MAFP), or with two ExoU-deficient mutants. Control noninfected and infected cells were assessed for the expression of: 1) TF mRNA by RT-PCR; 2) cell-associated TF by enzyme immunoassay and flow cytometry; 3) procoagulant activity by a colorimetric assay; and 4) microparticle-associated TF by flow cytometry. An enzyme immunoassay was also used to assess cell-associated TF in lung extracts from mice infected intratracheally with ExoU-producing and -deficient bacteria. Cells infected with the wild-type bacteria had higher levels of TF mRNA, cell-associated TF expression, procoagulant activity and released microparticle-associated TF than cells infected with the mutants. Bacterial treatment with MAFP significantly reduced the expression of TF by infected cells. Lung samples from mice infected with the wild-type bacteria exhibited higher levels of cell-associated TF and procoagulant activity. The present results demonstrate that ExoU may contribute to the pathogenesis of lung injury by inducing a tissue factor-dependent procoagulant activity in airway epithelial cells.

  3. Prevalence of extended spectrum beta lactamases among strains of Pseudomonas aeruginosa isolated from burn patients

    Directory of Open Access Journals (Sweden)

    Mirsalehian

    2008-08-01

    Full Text Available Background: The resistance of Pseudomonas aeruginosa strains to broad spectrum cephalosporins may be mediated by extended spectrum b-lactamases (ESBLs. These enzymes are encoded by different genes located either on chromosome or plasmids. In this study, we determined the antimicrobial resistance patterns of P. aeruginosa isolates and screened for ESBL production. Methods: After isolation from burn patients in Tehran Hospital, identification of P. aeruginosa isolates were assessed using biochemical tests. We then performed disk agar diffusion (DAD according to CLSI guidelines to determine the pattern of antimicrobial resistance. The frequency of ESBLs and prevalence of the OXA-10 and PER-1 genes were determined with combined disk and polymerase chain reaction (PCR methods, respectively. Results: One hundred strains of P. aeruginosa were isolated. The resistance of these strains to cephpodoxime, aztreonam, ciprofloxacin, ofloxacin, ceftazidime, cefepime, imipenem, meropenem, cefotaxime, levofloxacin, piperacilin- tazobactam and ceftriaxon was 100%, 90%, 83%, 92%, 85%, 88%, 63%, 66%, 98%, 89%, 70% and 91%, respectively. Of these, 40 strains (40% were ESBL positive, 29 strains (29% were OXA-10 positive and 18 strains (18% were PER-1 positive. Conclusion: Our results confirm the need for proper antimicrobial therapy in burn hospitals, considering the resistance pattern and frequency of strains producing ESBLs and the presence of the OXA-10 and PER-1 genes. Since an increase in the prevalence of ESBL in P. aeruginosa strains might lead to the transfer of these ESBL genes to other gram-negative bacteria, we recommend the use of appropriate drugs, especially cephalosporins, in burn hospitals.

  4. Molecular confirmation of shampoo as the putative source of Pseudomonas aeruginosa-induced postgrooming furunculosis in a dog.

    Science.gov (United States)

    Tham, Heng L; Jacob, Megan E; Bizikova, Petra

    2016-08-01

    An acute onset furunculosis due to Pseudomonas aeruginosa following grooming is a well recognized entity. Although contaminated shampoos have been suspected to be the source of the infection, a molecular confirmation of this association has been missing. This case report describes a dog with postgrooming furunculosis in which Pseudomonas aeruginosa with an identical genetic fingerprint was isolated from the skin lesions as well as from the shampoo used prior to the disease onset. The dog presented for lethargy, anorexia, pain and rapidly progressing skin lesions consistent with haemorrhagic papules, pustules, coalescing ulcers and crusts localized to the dorsal and lateral aspects of the thorax and gluteal region, which developed within 24 h after a bath. Cytology demonstrated suppurative inflammation with occasional intracellular rod-shaped bacteria. Bacterial culture from skin lesions and the shampoo bottle yielded Pseudomonas aeruginosa with an identical pulsed-field gel electrophoresis pattern. Treatment with oral ciprofloxacin and topical antimicrobial shampoo resulted in a complete resolution of skin lesions within eight weeks. Our clinical investigation suggests a link between Pseudomonas-contaminated shampoo and development of postgrooming furunculosis, and underscores the need for hygienic management of shampoos to help limit this disease. © 2016 ESVD and ACVD.

  5. Minimizing Pseudomonas aeruginosa adhesion to titanium surfaces by a plasma nitriding process

    Directory of Open Access Journals (Sweden)

    Michelle de Medeiros Aires

    2016-12-01

    Full Text Available The research of the interaction between bacteria-surface has great importance for titanium biomedical applications once microorganisms offer risks because promoting implant loss. Therefore, study bacterial adhesion and colonization on titanium is interesting because are principal factors infections pathogeny on biomaterials. In this study, commercial grade II titanium was submitted to nitriding treatment to plasma at 2.2 mbar, using gas mixtures of 80% hydrogen (H2 and 20% nitrogen (N2 during 1 hour and 3 hour. The surfaces were physically and chemically characterized. In order to evaluate bacterial response, the surfaces were exposed to Pseudomonas aeruginosa. The titanium surface modified in nitriding plasma, although exposes a higher roughness as compared with untreated samples, exhibited lower bacterial growth. The nitrided sample for 3 hour exhibited the higher amount of TiN phase and the higher concentration of atomic nitrogen on surface and lower bacterial adhered count. These results were confirmed by scanning electron microscopy. Based on these results can be said to the thermochemical treatment of plasma nitriding on titanium samples results a significant reduction of adherence of Pseudomonas aeruginosa. It was found that the Ti surface nitrided offers significant reduction of bacterial adherence which prevent biofilm formation and offersing lower risk of infection and implant remotion.

  6. Antibacterial properties of Chinese herbal medicines against nosocomial antibiotic resistant strains of Pseudomonas aeruginosa in Taiwan.

    Science.gov (United States)

    Liu, Ching-Shen; Cham, Thau-Ming; Yang, Cheng-Hong; Chang, Hsueh-Wei; Chen, Chia-Hong; Chuang, Li-Yeh

    2007-01-01

    Pseudomonas aeruginosa is well-recognized as a nosocomial pathogen, which exhibits inherent drug resistance. In this study, the antibacterial activity of ethanol extracts of 58 Chinese herbal medicines used in Taiwan were tested against 89 nosocomial antibiotic resistant strains of Pseudomonas aeruginosa. The results gathered by the disc diffusion method showed that 26 out of the 58 herbal extracts exhibited antibacterial activity. Among the 26 herbal extracts, 10 extracts showed broad-spectrum antibacterial activities and were selected for further antibacterial property assay. The minimum inhibitory concentrations (MIC) of the active partition fractions ranged from 0.25 to 11.0 mg/L. The presence of flavonoid compounds in the active fractions of test herbal extracts was observed by the TLC-bioautography. The results from the time-kill assay revealed that most of the herbal extracts completely killed the test organisms within 4 hours. Exposure of the test strains to a sub-MIC level of the herbal extracts for 10 consecutive subcultures did not induce resistance to the active components. A combination of the active herbal fractions with antibiotics showed that one of the herbal medicines, the hexane fraction of Ramulus Cinnamomi, possessed a synergistic effect with tetracycline, gentamycin, and streptomycin. In conclusion, the tested Chinese medical herbs have the potential to be developed into natural antibiotics. This is the first evaluation for screening large amounts of medical plants against nosocomial antibiotic resistant bacteria in Taiwan.

  7. Pseudomonas aeruginosa Aggregate Formation in an Alginate Bead Model System Exhibits In Vivo-Like Characteristics.

    Science.gov (United States)

    Sønderholm, Majken; Kragh, Kasper Nørskov; Koren, Klaus; Jakobsen, Tim Holm; Darch, Sophie E; Alhede, Maria; Jensen, Peter Østrup; Whiteley, Marvin; Kühl, Michael; Bjarnsholt, Thomas

    2017-05-01

    Alginate beads represent a simple and highly reproducible in vitro model system for diffusion-limited bacterial growth. In this study, alginate beads were inoculated with Pseudomonas aeruginosa and followed for up to 72 h. Confocal microscopy revealed that P. aeruginosa formed dense clusters similar in size to in vivo aggregates observed ex vivo in cystic fibrosis lungs and chronic wounds. Bacterial aggregates primarily grew in the bead periphery and decreased in size and abundance toward the center of the bead. Microsensor measurements showed that the O2 concentration decreased rapidly and reached anoxia ∼100 μm below the alginate bead surface. This gradient was relieved in beads supplemented with NO3- as an alternative electron acceptor allowing for deeper growth into the beads. A comparison of gene expression profiles between planktonic and alginate-encapsulated P. aeruginosa confirmed that the bacteria experienced hypoxic and anoxic growth conditions. Furthermore, alginate-encapsulated P. aeruginosa exhibited a lower respiration rate than the planktonic counterpart and showed a high tolerance toward antibiotics. The inoculation and growth of P. aeruginosa in alginate beads represent a simple and flexible in vivo-like biofilm model system, wherein bacterial growth exhibits central features of in vivo biofilms. This was observed by the formation of small cell aggregates in a secondary matrix with O2-limited growth, which was alleviated by the addition of NO3- as an alternative electron acceptor, and by reduced respiration rates, as well as an enhanced tolerance to antibiotic treatment.IMPORTANCEPseudomonas aeruginosa has been studied intensively for decades due to its involvement in chronic infections, such as cystic fibrosis and chronic wounds, where it forms biofilms. Much research has been dedicated to biofilm formation on surfaces; however, in chronic infections, most biofilms form small aggregates of cells not attached to a surface, but embedded in host

  8. Skin-Derived C-Terminal Filaggrin-2 Fragments Are Pseudomonas aeruginosa-Directed Antimicrobials Targeting Bacterial Replication.

    Directory of Open Access Journals (Sweden)

    Britta Hansmann

    2015-09-01

    Full Text Available Soil- and waterborne bacteria such as Pseudomonas aeruginosa are constantly challenging body surfaces. Since infections of healthy skin are unexpectedly rare, we hypothesized that the outermost epidermis, the stratum corneum, and sweat glands directly control the growth of P. aeruginosa by surface-provided antimicrobials. Due to its high abundance in the upper epidermis and eccrine sweat glands, filaggrin-2 (FLG2, a water-insoluble 248 kDa S100 fused-type protein, might possess these innate effector functions. Indeed, recombinant FLG2 C-terminal protein fragments display potent antimicrobial activity against P. aeruginosa and other Pseudomonads. Moreover, upon cultivation on stratum corneum, P. aeruginosa release FLG2 C-terminus-containing FLG2 fragments from insoluble material, indicating liberation of antimicrobially active FLG2 fragments by the bacteria themselves. Analyses of the underlying antimicrobial mechanism reveal that FLG2 C-terminal fragments do not induce pore formation, as known for many other antimicrobial peptides, but membrane blebbing, suggesting an alternative mode of action. The association of the FLG2 fragment with the inner membrane of treated bacteria and its DNA-binding implicated an interference with the bacterial replication that was confirmed by in vitro and in vivo replication assays. Probably through in situ-activation by soil- and waterborne bacteria such as Pseudomonads, FLG2 interferes with the bacterial replication, terminates their growth on skin surface and thus may contributes to the skin's antimicrobial defense shield. The apparent absence of FLG2 at certain body surfaces, as in the lung or of burned skin, would explain their higher susceptibility towards Pseudomonas infections and make FLG2 C-terminal fragments and their derivatives candidates for new Pseudomonas-targeting antimicrobials.

  9. Coexistence and Within-Host Evolution of Diversified Lineages of Hypermutable Pseudomonas aeruginosa in Long-term Cystic Fibrosis Infections

    DEFF Research Database (Denmark)

    Feliziani, Sofia; Marvig, Rasmus Lykke; Lujan, Adela M.

    2014-01-01

    history, respectively. We sequenced 11 isolates from a single sample from each patient to allow in-depth analysis of population diversity. Each patient was infected by clonal populations of bacteria that were dominated by mutators. The in vivo mutation rate of the populations was similar to 100 SNPs......The advent of high-throughput sequencing techniques has made it possible to follow the genomic evolution of pathogenic bacteria by comparing longitudinally collected bacteria sampled from human hosts. Such studies in the context of chronic airway infections by Pseudomonas aeruginosa in cystic...... to investigate within-host population diversity or long-term evolution of mutators in CF airways. We sequenced the genomes of 13 and 14 isolates of P. aeruginosa mutator populations from an Argentinian and a Danish CF patient, respectively. Our collection of isolates spanned 6 and 20 years of patient infection...

  10. Specific IgA against Pseudomonas aeruginosa in severe COPD

    Directory of Open Access Journals (Sweden)

    Millares L

    2017-09-01

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

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

    NARCIS (Netherlands)

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

    2016-01-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

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

    NARCIS (Netherlands)

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

    2000-01-01

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

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

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

    National Research Council Canada - National Science Library

    Kumar, Ravi; Chhibber, Sanjay; Harjai, Kusum

    2009-01-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

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

    NARCIS (Netherlands)

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

    2016-01-01

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

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

    National Research Council Canada - National Science Library

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

    1999-01-01

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

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

    DEFF Research Database (Denmark)

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

    2017-01-01

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

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

    Science.gov (United States)

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

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

    National Research Council Canada - National Science Library

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

    2011-01-01

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

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

    NARCIS (Netherlands)

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

    1982-01-01

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

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

    DEFF Research Database (Denmark)

    Kharazmi, A; Nielsen, H

    1991-01-01

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

  4. Pathogenic factors of Pseudomonas aeruginosa – the role of biofilm in pathogenicity and as a target for phage therapy

    Directory of Open Access Journals (Sweden)

    Fairoz Al-Wrafy

    2017-02-01

    Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen that can cause several acute and chronic infections in humans, and it has become an important cause of nosocomial infections and antibiotic resistance. Biofilm represents an important virulence factor for these bacteria, plays a role in P. aeruginosa infections and avoidance of immune defence mechanisms, and has the ability to protect the bacteria from antibiotics. Alginate, Psl and Pel, three exopolysaccharides, are the main components in biofilm matrix, with many biological functions attributed to them, especially with respect to the protection of the bacterial cell from antibiotics and the immune system. Pseudomonas infections, biofilm formation and development of resistance to antibiotics all require better understanding to achieve the best results using alternative treatment with phage therapy. This review describes the P. aeruginosa pathogenicity and virulence factors with a special focus on the biofilm and its role in infection and resistance to antibiotics and summarizes phage therapy as an alternative approach in treatment of P. aeruginosa infections.

  5. Novel experimental Pseudomonas aeruginosa lung infection model mimicking long-term host-pathogen interactions in cystic fibrosis

    DEFF Research Database (Denmark)

    Moser, Claus; van Gennip, Maria; Bjarnsholt, Thomas

    2009-01-01

    Moser C, van Gennip M, Bjarnsholt T, Jensen PO, Lee B, Hougen HP, Calum H, Ciofu O, Givskov M, Molin S, Hoiby N. Novel experimental Pseudomonas aeruginosa lung infection model mimicking long-term host-pathogen interactions in cystic fibrosis. APMIS 2009; 117: 95-107. The dominant cause of premature...... death in patients suffering from cystic fibrosis (CF) is chronic lung infection with Pseudomonas aeruginosa. The chronic lung infection often lasts for decades with just one clone. However, as a result of inflammation, antibiotic treatment and different niches in the lungs, the clone undergoes...... and 2003) of the chronic lung infection of one CF patient using the seaweed alginate embedment model. The results showed that the non-mucoid clones reduced their virulence over time, resulting in faster clearing of the bacteria from the lungs, improved pathology and reduced pulmonary production...

  6. Increased susceptibility to Pseudomonas aeruginosa infection under hindlimb-unloading conditions

    Science.gov (United States)

    Aviles, Hernan; Belay, Tesfaye; Fountain, Kimberly; Vance, Monique; Sonnenfeld, Gerald

    2003-01-01

    It has been reported that spaceflight conditions alter the immune system and resistance to infection [Belay T, Aviles H, Vance M, Fountain K, and Sonnenfeld G. J Allergy Clin Immunol 170: 262-268, 2002; Hankins WR and Ziegelschmid JF. In: Biomedical Results of Apollo. Washington, DC: NASA, 1975, p. 43-81. (NASA Spec. Rep. SP-368)]. Ground-based models, including the hindlimb-unloading model, have become important tools for increasing understanding of how spaceflight conditions can influence physiology. The objective of the present study was to determine the effect of hindlimb unloading on the susceptibility of mice to Pseudomonas aeruginosa infection. Hindlimb-unloaded and control mice were subcutaneously infected with 1 LD50 of P. aeruginosa. Survival, bacterial organ load, and antibody and corticosterone levels were compared among the groups. Hindlimb unloading had detrimental effects for infected mice. Animals in the hindlimb-unloaded group, compared with controls, 1). showed significantly increased mortality and reduced time to death, 2). had increased levels of corticosterone, and 3). were much less able to clear bacteria from the organs. These results suggest that hindlimb unloading may induce the production of corticosterone, which may play a critical role in the modulation of the immune system leading to increased susceptibility to P. aeruginosa infection.

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

    Science.gov (United States)

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

    2015-10-07

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

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

    Science.gov (United States)

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

    2011-01-18

    Pseudomonas aeruginosa, a gram-negative bacterium of clinical importance, forms more robust biofilm during anaerobic respiration, a mode of growth presumed to occur in abnormally thickened mucus layer lining the cystic fibrosis (CF) patient airway. However, molecular basis behind this anaerobiosis-triggered robust biofilm formation is not clearly defined yet. Here, we identified a morphological change naturally accompanied by anaerobic respiration in P. aeruginosa and investigated its effect on the biofilm formation in vitro. A standard laboratory strain, PAO1 was highly elongated during anaerobic respiration compared with bacteria grown aerobically. Microscopic analysis demonstrated that cell elongation likely occurred as a consequence of defective cell division. Cell elongation was dependent on the presence of nitrite reductase (NIR) that reduces nitrite (NO(2) (-)) to nitric oxide (NO) and was repressed in PAO1 in the presence of carboxy-PTIO, a NO antagonist, demonstrating that cell elongation involves a process to respond to NO, a spontaneous byproduct of the anaerobic respiration. Importantly, the non-elongated NIR-deficient mutant failed to form biofilm, while a mutant of nitrate reductase (NAR) and wild type PAO1, both of which were highly elongated, formed robust biofilm. Taken together, our data reveal a role of previously undescribed cell biological event in P. aeruginosa biofilm formation and suggest NIR as a key player involved in such process.

  9. Biophysicochemical characterization of Pyocin SA189 produced by Pseudomonas aeruginosa SA189.

    Science.gov (United States)

    Naz, Sehar Afshan; Jabeen, Nusrat; Sohail, Muhammad; Rasool, Sheikh Ajaz

    2015-01-01

    Pseudomonas aeruginosa, in spite of being a ubiquitous organism (as it is found in soil, water, and humans), is also an opportunistic pathogen. In order to maintain its diversity in the community, it produces various toxic proteins, known as, bacteriocins. In the present study, pyocin SA189, which is a bacteriocin produced by P. aeruginosa SA189 (isolated from a clinical sample) was characterized. P. aeruginosa SA189, as identified by the conventional and 16S rRNA gene amplification, produced pyocin SA189 of molecular weight of 66 k Da. The pyocin showed antimicrobial activity against several clinically relevant Gram-positive and Gram-negative bacteria and was substantially stable for wide ranges of temperature and pH. Furthermore, the pyocin also retained its biological activity upon treatment with metal ions, organic solvents, and various proteolytic and lipolytic enzymes. The data from the growth kinetics indicated that the maximum bacteriocin production occurred in the late log phase. Overall, our results signify the potential of pyocin SA189 as a bio-control agent.

  10. The roles of biofilm matrix polysaccharide Psl in mucoid Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Ma, Luyan; Wang, Shiwei; Wang, Di; Parsek, Matthew R; Wozniak, Daniel J

    2012-07-01

    The opportunistic pathogen Pseudomonas aeruginosa causes life-threatening, persistent infections in patients with cystic fibrosis (CF). Persistence is attributed to the ability of these bacteria to form structured communities (biofilms). Biofilms rely on an extracellular polymeric substances matrix to maintain structure. Psl exopolysaccharide is a key matrix component of nonmucoid biofilms, yet the role of Psl in mucoid biofilms is unknown. In this report, using a variety of mutants in a mucoid P. aeruginosa background, we found that deletion of Psl-encoding genes dramatically decreased their biofilm formation ability, indicating that Psl is also a critical matrix component of mucoid biofilms. Our data also suggest that the overproduction of alginate leads to mucoid biofilms, which occupy more space, whereas Psl-dependent biofilms are densely packed. These data suggest that Psl polysaccharide may have significant contributions in biofilm persistence in patients with CF and may be helpful for designing therapies for P. aeruginosa CF infection. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  11. Pseudomonas aeruginosa Enolase Influences Bacterial Tolerance to Oxidative Stresses and Virulence.

    Science.gov (United States)

    Weng, Yuding; Chen, Fei; Liu, Yiwei; Zhao, Qiang; Chen, Ronghao; Pan, Xiaolei; Liu, Chang; Cheng, Zhihui; Jin, Shouguang; Jin, Yongxin; Wu, Weihui

    2016-01-01

    Pseudomonas aeruginosa is a Gram negative opportunistic pathogenic bacterium, which causes acute and chronic infections. Upon entering the host, bacteria alter global gene expression to adapt to host environment and avoid clearance by the host. Enolase is a glycolytic enzyme involved in carbon metabolism. It is also a component of RNA degradosome, which is involved in RNA processing and gene regulation. Here, we report that enolase is required for the virulence of P. aeruginosa in a murine acute pneumonia model. Mutation of enolase coding gene (eno) increased bacterial susceptibility to neutrophil mediated killing, which is due to reduced tolerance to oxidative stress. Catalases and alkyl hydroperoxide reductases play a major role in protecting the cell from oxidative damages. In the eno mutant, the expression levels of catalases (KatA and KatB) were similar as those in the wild type strain in the presence of H2O2, however, the expression levels of alkyl hydroperoxide reductases (AhpB and AhpC) were significantly reduced. Overexpression of ahpB but not ahpC in the eno mutant fully restored the bacterial resistance to H2O2 as well as neutrophil mediated killing, and partially restored bacterial virulence in the murine acute pneumonia model. Therefore, we have identified a novel role of enolase in the virulence of P. aeruginosa.

  12. Penicillin-Binding Protein 3 Is Essential for Growth of Pseudomonas aeruginosa.

    Science.gov (United States)

    Chen, Wei; Zhang, Yong-Mei; Davies, Christopher

    2017-01-01

    Penicillin-binding proteins (PBPs) function as transpeptidases, carboxypeptidases, or endopeptidases during peptidoglycan synthesis in bacteria. As the well-known drug targets for β-lactam antibiotics, the physiological functions of PBPs and whether they are essential for growth are of significant interest. The pathogen Pseudomonas aeruginosa poses a particular risk to immunocompromised and cystic fibrosis patients, and infections caused by this pathogen are difficult to treat due to antibiotic resistance. To identify potential drug targets among the PBPs in P. aeruginosa, we performed gene knockouts of all the high-molecular-mass (HMM) PBPs and determined the impacts on cell growth and morphology, susceptibility to β-lactams, peptidoglycan structure, virulence, and pathogenicity. Disruptions of the transpeptidase domains of most HMM PBPs, including double disruptions, had only minimal effects on cell growth. The exception was PBP3, where cell growth occurred only when the protein was conditionally expressed on an integrated plasmid. Conditional deletion of PBP3 also caused a defect in cell division and increased susceptibility to β-lactams. Knockout of PBP1a led to impaired motility, and this observation, together with its localization at the cell poles, suggests its involvement in flagellar function. Overall, these findings reveal that PBP3 represents the most promising target for drug discovery against P. aeruginosa, whereas other HMM PBPs have less potential. Copyright © 2016 American Society for Microbiology.

  13. Antibacterial activity of a newly developed peptide-modified lysin against Acinetobacter baumannii and Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Hang eYang

    2015-12-01

    Full Text Available The global emergence of multidrug-resistant (MDR bacteria is a growing threat to public health worldwide. Natural bacteriophage lysins are promising alternatives in the treatment of infections caused by Gram-positive pathogens, but not Gram-negative ones, like Acinetobacter baumannii and Pseudomonas aeruginosa, due to the barriers posed by their outer membranes. Recently, modifying a natural lysin with an antimicrobial peptide was found able to break the barriers, and to kill Gram-negative pathogens. Herein, a new peptide-modified lysin (PlyA was constructed by fusing the cecropin A peptide residues 1–8 (KWKLFKKI with the OBPgp279 lysin and its antibacterial activity was studied. PlyA showed good and broad antibacterial activities against logarithmic phase A. baumannii and P. aeruginosa, but much reduced activities against the cells in stationary phase. Addition of outer membrane permeabilizers (EDTA and citric acid could enhance the antibacterial activity of PlyA against stationary phase cells. Finally, no antibacterial activity of PlyA could be observed in some bio-matrices, such as culture media, milk, and sera. In conclusion, we reported here a novel peptide-modified lysin with significant antibacterial activity against both logarithmic (without OMPs and stationary phase (with OMPs A. baumannii and P. aeruginosa cells in buffer, but further optimization is needed to achieve broad activity in diverse bio-matrices.

  14. Trehalose biosynthesis promotes Pseudomonas aeruginosa pathogenicity in plants.

    Science.gov (United States)

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

    2013-03-01

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

  15. Trehalose biosynthesis promotes Pseudomonas aeruginosa pathogenicity in plants.

    Directory of Open Access Journals (Sweden)

    Slavica Djonović

    2013-03-01

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

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

    Science.gov (United States)

    2016-03-15

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

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

    OpenAIRE

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

    2008-01-01

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

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

    OpenAIRE

    Zeynab Golshani; Ali Mohammad Ahadi; Ali Sharifzadeh

    2012-01-01

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

  19. Eradication of Pseudomonas aeruginosa biofilms by atmospheric pressure non-thermal plasma.

    Directory of Open Access Journals (Sweden)

    Mahmoud Y Alkawareek

    Full Text Available Bacteria exist, in most environments, as complex, organised communities of sessile cells embedded within a matrix of self-produced, hydrated extracellular polymeric substances known as biofilms. Bacterial biofilms represent a ubiquitous and predominant cause of both chronic infections and infections associated with the use of indwelling medical devices such as catheters and prostheses. Such infections typically exhibit significantly enhanced tolerance to antimicrobial, biocidal and immunological challenge. This renders them difficult, sometimes impossible, to treat using conventional chemotherapeutic agents. Effective alternative approaches for prevention and eradication of biofilm associated chronic and device-associated infections are therefore urgently required. Atmospheric pressure non-thermal plasmas are gaining increasing attention as a potential approach for the eradication and control of bacterial infection and contamination. To date, however, the majority of studies have been conducted with reference to planktonic bacteria and rather less attention has been directed towards bacteria in the biofilm mode of growth. In this study, the activity of a kilohertz-driven atmospheric pressure non-thermal plasma jet, operated in a helium oxygen mixture, against Pseudomonas aeruginosa in vitro biofilms was evaluated. Pseudomonas aeruginosa biofilms exhibit marked susceptibility to exposure of the plasma jet effluent, following even relatively short (≈ 10's s exposure times. Manipulation of plasma operating conditions, for example, plasma operating frequency, had a significant effect on the bacterial inactivation rate. Survival curves exhibit a rapid decline in the number of surviving cells in the first 60 seconds followed by slower rate of cell number reduction. Excellent anti-biofilm activity of the plasma jet was also demonstrated by both confocal scanning laser microscopy and metabolism of the tetrazolium salt, XTT, a measure of bactericidal

  20. Pseudomonas aeruginosa Microcolonies in Coronary Thrombi from Patients with ST-Segment Elevation Myocardial Infarction

    DEFF Research Database (Denmark)

    Hansen, Gorm Mørk; Belstrøm, Daniel; Nilsson, Carl Martin Peter

    2016-01-01

    Chronic infection is associated with an increased risk of atherothrombotic disease and direct bacterial infection of arteries has been suggested to contribute to the development of unstable atherosclerotic plaques. In this study, we examined coronary thrombi obtained in vivo from patients with ST...... and species specific probes was performed to visualize bacteria within thrombi. From the taxonomic analysis we identified a total of 55 different bacterial species. DNA from Pseudomonas aeruginosa represented the only species that was significantly associated with either thrombi or blood and was >30 times...... more abundant in thrombi than in arterial blood (pbiofilm microcolonies were detected in selected thrombi using universal and P. aeruginosa-specific PNA-FISH probes. P. aeruginosa and vascular biofilm infection in culprit lesions may play a role in STEMI...

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

    Directory of Open Access Journals (Sweden)

    Mohammad Hassani Sangani

    2015-04-01

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

  2. Phosphate limitation induces the intergeneric inhibition of Pseudomonas aeruginosa by Serratia marcescens isolated from paper machines.

    Science.gov (United States)

    Kuo, Pei-An; Kuo, Chih-Horng; Lai, Yiu-Kay; Graumann, Peter L; Tu, Jenn

    2013-06-01

    Phosphate is an essential nutrient for heterotrophic bacteria, affecting bacterioplankton in aquatic ecosystems and bacteria in biofilms. However, the influence of phosphate limitation on bacterial competition and biofilm development in multispecies populations has received limited attention in existing studies. To address this issue, we isolated 13 adhesive bacteria from paper machine aggregates. Intergeneric inhibition of Pseudomonas aeruginosa WW5 by Serratia marcescens WW4 was identified under phosphate-limited conditions, but not in Luria-Bertani medium or M9 minimal medium. The viable numbers of the pure S. marcescens WW4 culture decreased over 3 days in the phosphate-limited medium; however, the mortality of S. marcescens WW4 was significantly reduced when it was co-cultured with P. aeruginosa WW5, which appeared to sustain the S. marcescens WW4 biofilm. In contrast, viable P. aeruginosa WW5 cells immediately declined in the phosphate-limited co-culture. To identify the genetic/inhibitory element(s) involved in this process, we inserted a mini-Tn5 mutant of S. marcescens WW4 that lacked inhibitory effect. The results showed that an endonuclease bacteriocin was involved in this intergeneric inhibition by S. marcescens WW4 under phosphate limitation. In conclusion, this study highlights the importance of nutrient limitation in bacterial interactions and provides a strong candidate gene for future functional characterisation. © 2013 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

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

    Science.gov (United States)

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

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

    NARCIS (Netherlands)

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

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

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

    DEFF Research Database (Denmark)

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

    2009-01-01

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

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

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2007-01-01

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

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

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

    NARCIS (Netherlands)

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

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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

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

    DEFF Research Database (Denmark)

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

    2017-01-01

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

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

    NARCIS (Netherlands)

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

    2015-01-01

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

  13. Contamination of Tap Water with Pseudomonas aeruginosa, Legionella pneumophila, and Escherichia coli in Guilan, Iran

    Directory of Open Access Journals (Sweden)

    Masoumeh Ahmadi Jalali Moghadam

    2016-12-01

    Full Text Available Background: River and underground waters are main sources of tap water in Guilan, Iran. Overlandwastes move into rivers during periods of heavy or extended rain that is very common in the area.Pseudomonas aeruginosa, Legionella pneumophila, and Escherichia coli are main human pathogenswith water source. This study is designed to determine the load of these bacteria in main water suppliesof the area.Methods: Samples were collected directly into sterile containers, concentrated by centrifuge,inoculated in enrichment medium and incubated for 3-4 days. DNA was extracted by using commercialkit. Several rounds of PCR was performed to search P. aeroginosa, integron I, Metallo-β-lactamasesgene, L. pneumophila, mip gene, and E. coli.Results: About 92.0% of the samples showed bacterial contamination as revealed by PCR with primersof 16S rRNAgene, 9.5% of the samples had L. pneumophila, and 11,1% had Pseudomonas aeruginosa,but Escherichia coli was not detected. We found the mip gene in 66.6% of the samples with L.pneumophila. Metallo-β-lactamasesgene was found in 11.1% of all samples. We also found Integrin 1in 28.5% of the samples with P. aeruginosa.Conclusion: This study indicates that in spite of chlorination, total bacterial contamination of potwaters in the area is high and contamination with L. pneumophila and P. aeroginosa is considerable. Itmight be related to the biofilm formation and the growth of water microflora. It seems that free residualchlorine is ineffective. We suggest a more effective decontamination procedure based on moderntechnology.

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  15. Bioactive proteins from Solanaceae as quorum sensing inhibitors against virulence in Pseudomonas aeruginosa.

    Science.gov (United States)

    Singh, Gurpreet; Tamboli, Ekant; Acharya, Aurovind; Kumarasamy, Chellan; Mala, Kanchana; Raman, Pachaiappan

    2015-06-01

    Cell-to-cell communication or quorum sensing (QS) is a generic event in bacteria that is used to coordinate gene expression among local populations. The phenomenon of QS depends on the fact that presence of sufficient bacteria ascertains a threshold level of autoinducer concentration that allows bacteria to sense a critical cell mass and to activate or repress target genes. Thus, QS has been an attractive target for the development of anti-infective strategies that are not based on the use of antibiotics. Several anti-QS approaches have been demonstrated including natural products from plant-based secondary metabolites. However, the role of plant bioactive proteins as an anti-QS peptide is yet to be deciphered. Against a backdrop of ever-increasing antibiotic resistant pathogens, there is a strong need for development of alternative therapeutic strategies. Thus, our hypothesis is that bioactive proteins from the plant family Solanaceae are quorum quenching molecules that can be exploited to develop a therapeutic strategy against virulence. We presume that bioactive proteins will inactivate or inhibit or degrade QS signals from bacteria to prevent cell-to-cell communication and thus inhibit development of virulence in Pseudomonas aeruginosa. Further, the use of proteins as quorum quenchers will delay the bacteria to develop resistance against these quenching molecules. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Copper homeostasis networks in the bacterium Pseudomonas aeruginosa.

    Science.gov (United States)

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

    2017-09-22

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

  17. Phosphorylcholine Phosphatase: A Peculiar Enzyme of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Domenech

    2011-01-01

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

  18. Structural Characterization of Novel Pseudomonas aeruginosa Type IV Pilins

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-01

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

  19. Genome diversity of Pseudomonas aeruginosa PAO1 laboratory strains.

    Science.gov (United States)

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

    2010-02-01

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

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

    Science.gov (United States)

    Muller, Michael; Merrett, Neil D

    2014-09-01

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

  1. Crystal structure of the flavoenzyme PA4991 from Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-22

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

  2. Horizontal transfer of the blaNDM-1 gene to Pseudomonas aeruginosa and Acinetobacter baumannii in biofilms.

    Science.gov (United States)

    Tanner, Windy D; Atkinson, Robyn M; Goel, Ramesh K; Toleman, Mark A; Benson, Lowell Scott; Porucznik, Christina A; VanDerslice, James A

    2017-04-01

    Horizontal gene transfer has contributed to the global spread of the blaNDM-1 gene. Multiple studies have demonstrated plasmid transfer of blaNDM-1 between Gram-negative bacteria, primarily Enterobacteriaceae species, but conjugational transfer of natural blaNDM-1 plasmids from Enterobacteriaceae into Pseudomonas aeruginosa and Acinetobacter baumannii has not previously been shown. As P. aeruginosa and A. baumannii are both typically strong biofilm formers, transfer of natural blaNDM-1 plasmids could potentially occur more readily in this environment. To determine whether natural blaNDM-1 plasmids could transfer to P. aeruginosa or A. baumannii in biofilms, three clinical and environmental Enterobacteriaceae strains carrying NDM-1-encoding plasmids of different incompatibility types were mated with E. coli J53, producing E. coli J53- blaNDM-1 transconjugants. Subsequently, dual-species biofilms were created using the E. coli J53 transconjugants as plasmid donors and either P. aeruginosa or A. baumannii as recipients. Biofilm transfer of NDM-encoding plasmids to P. aeruginosa and A. baumannii was successful from one and two E. coli J53- blaNDM-1 transconjugants, respectively. This demonstrates the potential for the spread of blaNDM-1, genes to P. aeruginosa and A. baumannii in clinical and environmental settings. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Pseudomonas aeruginosa RhlR is required to neutralize the cellular immune response in a Drosophila melanogaster oral infection model

    Science.gov (United States)

    Limmer, Stefanie; Haller, Samantha; Drenkard, Eliana; Lee, Janice; Yu, Shen; Kocks, Christine; Ausubel, Frederick M.; Ferrandon, Dominique

    2011-01-01

    An in-depth mechanistic understanding of microbial infection necessitates a molecular dissection of host–pathogen relationships. Both Drosophila melanogaster and Pseudomonas aeruginosa have been intensively studied. Here, we analyze the infection of D. melanogaster by P. aeruginosa by using mutants in both host and pathogen. We show that orally ingested P. aeruginosa crosses the intestinal barrier and then proliferates in the hemolymph, thereby causing the infected flies to die of bacteremia. Host defenses against ingested P. aeruginosa included an immune deficiency (IMD) response in the intestinal epithelium, systemic Toll and IMD pathway responses, and a cellular immune response controlling bacteria in the hemocoel. Although the observed cellular and intestinal immune responses appeared to act throughout the course of the infection, there was a late onset of the systemic IMD and Toll responses. In this oral infection model, P. aeruginosa PA14 did not require its type III secretion system or other well-studied virulence factors such as the two-component response regulator GacA or the protease AprA for virulence. In contrast, the quorum-sensing transcription factor RhlR, but surprisingly not LasR, played a key role in counteracting the cellular immune response against PA14, possibly at an early stage when only a few bacteria are present in the hemocoel. These results illustrate the power of studying infection from the dual perspective of host and pathogen by revealing that RhlR plays a more complex role during pathogenesis than previously appreciated. PMID:21987808

  4. Epidemiology and Drug Susceptibility of Pseudomonas aeruginosa Strains isolated from Patients admitted to Zabol hospitals: Short Communication

    Directory of Open Access Journals (Sweden)

    Forough Heydari

    2015-12-01

    Full Text Available Background and Aim: Pseudomonas aeruginosa is one of the most important causative agents of nosocomial infections that threatens many lives .. Regarding the innate and adaptive ability of the bacteria species to become resistant to many antimicrobial agents, recognition of different antibiotic resistance patterns is extremely significant in assessing the validity of the monitoring programs. Also, the pattern of genetic isolates is essential in the management of infections caused by these bacteria. The purpose of this study was to determine genetic diversity and patterns of antimicrobial resistance of P. aeruginosa isolates using RAPD-PCR. Materials and Methods: The present study aimed at assessing the genetic diversity and antibiotic resistant pattern of P. aeruginosa isolates in the educational Zabol hospitals. Thus, antibiotic susceptibility of 100 isolates was determined applying Kirby-Bauer disk diffusion method. Results: RAPD-PCR data revealed  a high level of polymorphism among the isolates of P. aeruginosa in Sistan. But, no association was observed between antibiotic susceptibility and genetic diversity pattern. Conclusion: In the present study, we RAPD-PCR technique was found to be a useful means for the investigation of the genetic variation and epidemiological study among P. aeruginosa isolates collected from Sistan region.

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

    Directory of Open Access Journals (Sweden)

    Popov М. М.

    2017-06-01

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

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

    NARCIS (Netherlands)

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

    2001-01-01

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

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

    DEFF Research Database (Denmark)

    Zhang, Lianbo; Gao, Qingguo; Chen, Wanying

    2013-01-01

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

  8. CdiGMP signaling at early stages of biofilm formation in Pseudomonas Aeruginosa

    Science.gov (United States)

    Zhao, Kun; Gibiansky, Maxsim; Xian, Wujing; Utada, Andrew; Wong, Gerard

    2014-03-01

    Biofilm communities on surfaces constitute an important physiological state of bacteria. CdiGMP is a secondary messenger that has recently emerged as a master regulator of biofilm behavior. It has been shown that cdiGMP can affect bacterial adhesion, motility and exopolysaccharides production, which are important in regulating biofilm formation. However, at a single cell level, the details of how cdiGMP regulate bacterial behavior are largely unknown. Here we examine the dynamics of intracellular cdiGMP levels at early stages of biofilm in Pseudomonas Aeruginosa, by using cell tracking techniques. We show that cells with different cdiGMP levels play different roles in the microcolony development at early stages of biofilm. The correlation between Psl and cdiGMP levels is also investigated.

  9. Effect of heavy-metal on synthesis of siderophores by Pseudomonas aeruginosa ZGKD3

    Science.gov (United States)

    Shi, Peili; Xing, Zhukang; Zhang, Yuxiu; Chai, Tuanyao

    2017-01-01

    Most siderophore-producing bacteria could improve the plant growth. Here, the effect of heavy-metal on the growth, total siderophore and pyoverdine production of the Cd tolerance Pseudomonas aeruginosa ZGKD3 were investigated. The results showed that ZGKD3 exhibited tolerance to heavy metals, and the metal tolerance decreased in the order Mn2+>Pb2+>Ni2+>Cu2+>Zn2+>Cd2+. The total siderophore and pyoverdine production of ZGKD3 induced by metals of Cd2+, Cu2+, Zn2+, Ni2+, Pb2+ and Mn2+ were different, the total siderophore and pyoverdine production reduced in the order Cd2+>Pb2+>Mn2+>Ni2+>Zn2+ >Cu2+ and Zn2+>Cd2+>Mn2+>Pb2+>Ni2+>Cu2+, respectively. These results suggested that ZGKD3 could grow in heavy-metal contaminated soil and had the potential of improving phytoremediation efficiency in Cd and Zn contaminated soils.

  10. Phenotypes of Non-Attached Pseudomonas aeruginosa Aggregates Resemble Surface Attached Biofilm

    DEFF Research Database (Denmark)

    Alhede, Morten; Kragh, Kasper Nørskov; Qvortrup, Klaus

    2011-01-01

    conditions. However, microscopic investigations of samples isolated from sites of chronic infections seem to suggest that some bacteria do not need to be attached to surfaces in order to establish chronic infections. In this study we employed scanning electron microscopy, confocal laser scanning microscopy......, RT-PCR as well as traditional culturing techniques to study the properties of Pseudomonas aeruginosa aggregates. We found that non-attached aggregates from stationary-phase cultures have comparable growth rates to surface attached biofilms. The growth rate estimations indicated that, independently...... the physiological states of the aggregates and particular matrix components. Bacterial surface-attachment and subsequent biofilm formation are considered hallmarks of the capacity of microbes to cause persistent infections. We have observed non-attached aggregates in the lungs of cystic fibrosis patients; otitis...

  11. Disinfection of Pseudomonas aeruginosa biofilm contaminated tube lumens with ultraviolet C light emitting diodes

    DEFF Research Database (Denmark)

    Bak, Jimmy; Ladefoged, S.D.; Tvede, M.

    2010-01-01

    , however, be applied to obtain 99.9% disinfection rates. The major reason was that besides cells the mature biofilm contained absorbing and scattering particulates, which made the biofilm opaque. The potential of UVC light emitting diodes ( LED) for disinfection purposes in catheter-like tubes contaminated...... with biofilm was investigated. It was shown that UVC light propagation was possible through both Teflon and catheter tubes ( silicone). The disinfection efficiency of the diodes was demonstrated on tubes contaminated artificially with a Pseudomonas aeruginosa biofilm. The tubes were connected to a flow system......Bacterial biofilms on long-term catheters are a major source of infection. Exposure to ultraviolet C (UVC - 265 nm) light was shown in an earlier study to reduce the number of bacteria substantially on ex vivo treated urinary patient catheters. Very large doses ( long treatment times) should...

  12. Disinfection of Pseudomonas aeruginosa biofilm contaminated tube lumens with ultraviolet C light emitting diodes

    DEFF Research Database (Denmark)

    Bak, Jimmy; Ladefoged, Søren D; Tvede, Michael

    2010-01-01

    , however, be applied to obtain 99.9% disinfection rates. The major reason was that besides cells the mature biofilm contained absorbing and scattering particulates, which made the biofilm opaque. The potential of UVC light emitting diodes (LED) for disinfection purposes in catheter-like tubes contaminated...... with biofilm was investigated. It was shown that UVC light propagation was possible through both Teflon and catheter tubes (silicone). The disinfection efficiency of the diodes was demonstrated on tubes contaminated artificially with a Pseudomonas aeruginosa biofilm. The tubes were connected to a flow system......Bacterial biofilms on long-term catheters are a major source of infection. Exposure to ultraviolet C (UVC - 265 nm) light was shown in an earlier study to reduce the number of bacteria substantially on ex vivo treated urinary patient catheters. Very large doses (long treatment times) should...

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    BACKGROUND: Pseudomonas aeruginosa is a pathogen that frequently colonizes patients with cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD). Several pathogens are known to bind vitronectin to increase their virulence. Vitronectin has been shown to enhance P. aeruginosa adhesion...

  14. Identification of Fitness Determinants during Energy-Limited Growth Arrest in Pseudomonas aeruginosa.

    Science.gov (United States)

    Basta, David W; Bergkessel, Megan; Newman, Dianne K

    2017-11-28

    Microbial growth arrest can be triggered by diverse factors, one of which is energy limitation due to scarcity of electron donors or acceptors. Genes that govern fitness during energy-limited growth arrest and the extent to which they overlap between different types of energy limitation are poorly defined. In this study, we exploited the fact that Pseudomonas aeruginosa can remain viable over several weeks when limited for organic carbon (pyruvate) as an electron donor or oxygen as an electron acceptor. ATP values were reduced under both types of limitation, yet more severely in the absence of oxygen. Using transposon-insertion sequencing (Tn-seq), we identified fitness determinants in these two energy-limited states. Multiple genes encoding general functions like transcriptional regulation and energy generation were required for fitness during carbon or oxygen limitation, yet many specific genes, and thus specific activities, differed in their relevance between these states. For instance, the global regulator RpoS was required during both types of energy limitation, while other global regulators such as DksA and LasR were required only during carbon or oxygen limitation, respectively. Similarly, certain ribosomal and tRNA modifications were specifically required during oxygen limitation. We validated fitness defects during energy limitation using independently generated mutants of genes detected in our screen. Mutants in distinct functional categories exhibited different fitness dynamics: regulatory genes generally manifested a phenotype early, whereas genes involved in cell wall metabolism were required later. Together, these results provide a new window into how P. aeruginosa survives growth arrest.IMPORTANCE Growth-arrested bacteria are ubiquitous in nature and disease yet understudied at the molecular level. For example, growth-arrested cells constitute a major subpopulation of mature biofilms, serving as an antibiotic-tolerant reservoir in chronic infections

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

    Science.gov (United States)

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

    2014-05-27

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

  16. 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.

  17. Dermal Wound Transcriptomic Responses to Infection with Pseudomonas aeruginosa versus Klebsiella pneumoniae in a Rabbit Ear Wound Model

    Science.gov (United States)

    2014-05-02

    Dermal wound transcriptomic responses to Infection with Pseudomonas aeruginosa versus Klebsiella pneumoniae in a rabbit ear wound model Kai P Leung Pt...with Klebsiella pneumoniae (Kp.) or Pseudomonas aeruginosa (P.o.) would indicate host responses associated with the worse healing of P.o. than Kp...responses to injection with Pseudomonas aeruginosa versus Klebsiella pneumoniae in a rabbit ear wound model 5a. CONTRACT NUMBER 5b. GRANT NUMBER

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

    Directory of Open Access Journals (Sweden)

    Zhizhou Kuang

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

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

    Science.gov (United States)

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

    2013-03-01

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

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

    Science.gov (United States)

    Damlund, Dina Silke Malling; Christophersen, Lars; Jensen, Peter Østrup; Alhede, Morten; Høiby, Niels; Moser, Claus

    2016-06-01

    The majority of cystic fibrosis (CF) patients acquire chronic Pseudomonas aeruginosa lung infection, resulting in increased mortality and morbidity. The chronic P. aeruginosa lung infection is characterized by bacteria growing in biofilm surrounded by polymorphonuclear neutrophils (PMNs). However, the infection is not eradicated and the inflammatory response leads to gradual degradation of the lung tissue. In CF patients, a Th2-dominated adaptive immune response with a pronounced antibody response is correlated with poorer outcome. Dendritic cells (DCs) are crucial in bridging the innate immune system with the adaptive immune response. Once activated, the DCs deliver a set of signals to uncommitted T cells that induce development, such as expansion of regulatory T cells and polarization of Th1, Th2 or Th17 subsets. In this study, we characterized DCs in lungs and regional lymph nodes in BALB/c mice infected using intratracheal installation of P. aeruginosa embedded in seaweed alginate in the lungs. A significantly elevated concentration of DCs was detected earlier in the lungs than in the regional lymph nodes. To evaluate whether the chronic P. aeruginosa lung infection leads to activation of DCs, costimulatory molecules CD80 and CD86 were analyzed. During infection, the DCs showed significant elevation of CD80 and CD86 expression in both the lungs and the regional lymph nodes. Interestingly, the percentage of CD86-positive cells was significantly higher than the percentage of CD80-positive cells in the lymph nodes. In addition, cytokine production from Lipopolysaccharides (LPS)-stimulated DCs was analyzed demonstrating elevated production of IL-6, IL-10 and IL-12. However, production of IL-12 was suppressed earlier than IL-6 and IL-10. These results support that DCs are involved in skewing of the Th1/Th2 balance in CF and may be a possible treatment target. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  1. Study on Hydro-Alcoholic Extract Effect of Pomegranate Peel on Pseudomonas aeruginosa Biofilm Formation

    Directory of Open Access Journals (Sweden)

    R. Habibipour

    2015-10-01

    Full Text Available Introduction & Objective: Microorganisms form biomass as biofilm in response to many factors, in order to adapt to hostile extracellular environments and biocides. Using different herbal compounds are of those strategies to deal with biofilm. It has been proved that plants extracts such as pomegranate, raspberry and chamomile essential oils have anti-biofilm effects. This study aimed to evaluate the effect of different concentrations of black peel pomegranate ex-tract on Pseudomonas aeruginosa biofilm formation. Materials & Methods: In this experimental research the anti-biofilm effect, reducing the amount of biofilm formation and growth kinetics of Pseudomonas aeruginosa in different treatments was measured by microtiter and plate colorimetric crystal violet method. Biofilm formation was also examined using a microscope. Statistical analysis of data obtained from the reading of the ELISA was performed using SPSS software, P value 0.05. Results: Findings of this study showed that bacteria cannot form any biofilm in first 6 hours of incubation, in all treatments. The amount of biofilm formation after 12 hours in 0.01 and 0.05 g/ mL treatments were medium. Among treatments, after 18 and 24 hours of incubation 0.001 g/ mL concentration of pomegranate peel extract had medium and strong inhibitory effect on biofilm formation, respectively. Conclusion: Results of this study showed that biofilm formation and biofilm reduction percent-age is directly related to the duration of exposure of bacteria that could be due to the different phases of growth. Growth kinetics study also revealed that in the majority of treatments the growth was incremental up to about 15 hours and decrement afterwards due to the effective-ness of different treatments. After 18 hours, treatments have greatest influence on biofilm formation. The foregoing has been fully confirmed by the results of microscopic slides. (Sci J Hamadan Univ Med Sci 2015; 22 (3: 195-202

  2. Polysaccharides serve as scaffold of biofilms formed by mucoid Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Yang, Liang; Hengzhuang, Wang; Wu, Hong

    2012-01-01

    Chronic lung infection by mucoid Pseudomonas aeruginosa is one of the major pathologic features in patients with cystic fibrosis. Mucoid P. aeruginosa is notorious for its biofilm forming capability and resistance to immune attacks. In this study, the roles of extracellular polymeric substances...... from biofilms formed by mucoid P. aeruginosa were investigated. Alginate is not an essential structure component for mucoid P. aeruginosa biofilms. Genetic studies revealed that Pel and Psl polysaccharides serve as essential scaffold and mediate macrocolony formation in mucoid P. aeruginosa biofilms....... The Psl polysaccharide is more important than Pel polysaccharide in mucoid P. aeruginosa biofilm structure maintenance and phagocytosis resistance. The polysaccharides were further found to protect mucoid P. aeruginosa strain from host immune clearance in a mouse model of acute lung infection....

  3. [The antibacterial activity of oregano essential oil (Origanum heracleoticum L.) against clinical strains of Escherichia coli and Pseudomonas aeruginosa].

    Science.gov (United States)

    Sienkiewicz, Monika; Wasiela, Małgorzata; Głowacka, Anna

    2012-01-01

    The aim of this study was to investigate the antibacterial properties of oregano (Origanum heracleoticum L.) essential oil against clinical strains of Escherichia coli and Pseudomonas aeruginosa. The antibacterial activity of oregano essential oil was investigate against 2 tested and 20 clinical bacterial strains of Escherichia coli and 20 clinical strains o Pseudomonas aeruginosa come from patients with different clinical conditions. The agar dilution method was used for microbial growth inhibition at various concentrations ofoil. Susceptibility testing to antibiotics was carried out using disc-diffusion method. The results of experiments showed that the tested oil was active against all of the clinical strains from both genus of bacteria, but strains of Escherichia coli were more sensitive to tested oil. Essential oil from Origanum heracleoticum L. inhibited the growth of Escherichia coli and Pseudomonas aeruginosa clinical strains with different patters of resistance. The obtained outcomes will enable further investigations using oregano essential oil obtained from Origanum heracleoticum L. as alternative antibacterial remedies enhancing healing process in bacterial infections and as an effective means for the prevention of antibiotic-resistant strain development.

  4. Biofilm assembly becomes crystal clear – filamentous bacteriophage organize the Pseudomonas aeruginosa biofilm matrix into a liquid crystal

    Directory of Open Access Journals (Sweden)

    Patrick R. Secor

    2015-12-01

    Full Text Available Pseudomonas aeruginosa is an opportunistic bacterial pathogen associated with many types of chronic infection. At sites of chronic infection, such as the airways of people with cystic fibrosis (CF, P. aeruginosa forms biofilm-like aggregates. These are clusters of bacterial cells encased in a polymer-rich matrix that shields bacteria from environmental stresses and antibiotic treatment. When P. aeruginosa forms a biofilm, large amounts of filamentous Pf bacteriophage (phage are produced. Unlike most phage that typically lyse and kill their bacterial hosts, filamentous phage of the genus Inovirus, which includes Pf phage, often do not, and instead are continuously extruded from the bacteria. Here, we discuss the implications of the accumulation of filamentous Pf phage in the biofilm matrix, where they interact with matrix polymers to organize the biofilm into a highly ordered liquid crystal. This structural configuration promotes bacterial adhesion, desiccation survival, and antibiotic tolerance – all features typically associated with biofilms. We propose that Pf phage make structural contributions to P. aeruginosa biofilms and that this constitutes a novel form of symbiosis between bacteria and bacteriophage.

  5. Biosurfactant Production by Pseudomonas aeruginosa from Renewable Resources.

    Science.gov (United States)

    Thavasi, R; Subramanyam Nambaru, V R M; Jayalakshmi, S; Balasubramanian, T; Banat, Ibrahim M

    2011-01-01

    This study deals with production and characterization of biosurfactant from renewable resources by Pseudomonas aeruginosa. Biosurfactant production was carried out in 3L fermentor using waste motor lubricant oil and peanut oil cake. Maximum biomass (11.6 mg/ml) and biosurfactant production (8.6 mg/ml) occurred with peanut oil cake at 120 and 132 h respectively. Characterization of the biosurfactant revealed that, it is a lipopeptide with chemical composition of protein (50.2%) and lipid (49.8%). The biosurfactant (1 mg/ml) was able to emulsify waste motor lubricant oil, crude oil, peanut oil, kerosene, diesel, xylene, naphthalene and anthracene, comparatively the emulsification activity was higher than the activity found with Triton X-100 (1 mg/ml). Results obtained in the present study showed the possibility of biosurfactant production using renewable, relatively inexpensive and easily available resources. Emulsification activity found with the biosurfactant against different hydrocarbons showed its possible application in bioremediation of environments polluted with various hydrocarbons.

  6. Pa0148 from Pseudomonas aeruginosa Catalyzes the Deamination of Adenine

    Energy Technology Data Exchange (ETDEWEB)

    A Goble; Z Zhang; J Sauder; S Burley; S Swaminathan; F Raushel

    2011-12-31

    Four proteins from NCBI cog1816, previously annotated as adenosine deaminases, have been subjected to structural and functional characterization. Pa0148 (Pseudomonas aeruginosa PAO1), AAur1117 (Arthrobacter aurescens TC1), Sgx9403e, and Sgx9403g have been purified and their substrate profiles determined. Adenosine is not a substrate for any of these enzymes. All of these proteins will deaminate adenine to produce hypoxanthine with k{sub cat}/K{sub m} values that exceed 10{sup 5} M{sup -1} s{sup -1}. These enzymes will also accept 6-chloropurine, 6-methoxypurine, N-6-methyladenine, and 2,6-diaminopurine as alternate substrates. X-ray structures of Pa0148 and AAur1117 have been determined and reveal nearly identical distorted ({beta}/{alpha}){sub 8} barrels with a single zinc ion that is characteristic of members of the amidohydrolase superfamily. Structures of Pa0148 with adenine, 6-chloropurine, and hypoxanthine were also determined, thereby permitting identification of the residues responsible for coordinating the substrate and product.

  7. Production and characterization of rhamnolipids from Pseudomonas aeruginosa san ai

    Directory of Open Access Journals (Sweden)

    Rikalovic Milena G.

    2012-01-01

    Full Text Available Production and characterization of rhamnolipid biosurfactant obtained by strain Pseudomonas aeruginosa san ai was investigated. With regard to carbon and nitrogen source several media were tested to enhance production of rhamnolipids. Phosphate-limited proteose peptone-ammonium salt (PPAS medium supplemented with sun flower oil as a source of carbon and mineral ammonium chloride and peptone as a nitrogen source greatly improved rhamnolipid production, from 0.15 on basic PPAS (C/N ratio 4.0, to 3 g L-1, on optimized PPAS medium (C/N ratio 7.7. Response surface methodology analysis was used for testing effect of three factors: temperature, concentration of carbon and nitrogen source (w/w, in optimized PPAS medium on rhamnolipid production. Isolated rhamnolipids were characterized by IR and ESI-MS. IR spectra confirmed that isolated compound corresponds to rhamnolipid structure, whereas MS indicated that isolated preparation is a mixture of mono-rhamno-mono-lipidic, mono-rhamno-di-lipidic- and dirhamno- di-lipidic congeners.

  8. PA0148 from Pseudomonas aeruginosa Catalyzes the Deamination of Adenine

    Energy Technology Data Exchange (ETDEWEB)

    Goble, A.M.; Swaminathan, S.; Zhang, Z.; Sauder, J. M.; Burley, S. K.; Raushel, F. M.

    2011-08-02

    Four proteins from NCBI cog1816, previously annotated as adenosine deaminases, have been subjected to structural and functional characterization. Pa0148 (Pseudomonas aeruginosa PAO1), AAur1117 (Arthrobacter aurescens TC1), Sgx9403e, and Sgx9403g have been purified and their substrate profiles determined. Adenosine is not a substrate for any of these enzymes. All of these proteins will deaminate adenine to produce hypoxanthine with k{sub cat}/K{sub m} values that exceed 10{sup 5} M{sup -1} s{sup -1}. These enzymes will also accept 6-chloropurine, 6-methoxypurine, N-6-methyladenine, and 2,6-diaminopurine as alternate substrates. X-ray structures of Pa0148 and AAur1117 have been determined and reveal nearly identical distorted ({beta}/{alpha}){sub 8} barrels with a single zinc ion that is characteristic of members of the amidohydrolase superfamily. Structures of Pa0148 with adenine, 6-chloropurine, and hypoxanthine were also determined, thereby permitting identification of the residues responsible for coordinating the substrate and product.

  9. Alkaline protease contributes to pyocyanin production in Pseudomonas aeruginosa.

    Science.gov (United States)

    Iiyama, Kazuhiro; Takahashi, Eigo; Lee, Jae Man; Mon, Hiroaki; Morishita, Mai; Kusakabe, Takahiro; Yasunaga-Aoki, Chisa

    2017-04-01

    The role of the alkaline protease (AprA) in pyocyanin production in Pseudomonas aeruginosa was investigated. AprA was overproduced when a plasmid carrying the aprA gene was introduced to an aprA-deletion mutant strain, EG03; thus, aprA-complemented EG03 was used as an overproducing strain. The complemented strain produced higher pyocyanin than the mutant strain in all commercially available media evaluated. Particularly, pyocyanin production was higher in the complemented than in the parental strain in brain-heart infusion and tryptic soy broths. These results suggested that protein degradation products by AprA were utilized for pyocyanin production. Protein-rich media were used in subsequent validation studies. Similar results were obtained when the basal medium was supplemented with casein or skim milk as the sole organic nitrogen source. However, gelatin failed to induce abundant pyocyanin production in the complemented strain, despite the presence of protein degradation products by AprA as assessed by SDS-PAGE. Thus, gelatin degradation products may not be suitable for pyocyanin synthesis. In conclusion, AprA could contribute to pyocyanin production in the presence of several proteins or peptides. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Subversion of mucosal barrier polarity by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Joanne eEngel

    2011-05-01

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

  11. The cost of multiple drug resistance in Pseudomonas aeruginosa.

    Science.gov (United States)

    Ward, H; Perron, G G; Maclean, R C

    2009-05-01

    The spread of bacterial antibiotic resistance mutations is thought to be constrained by their pleiotropic fitness costs. Here we investigate the fitness costs of resistance in the context of the evolution of multiple drug resistance (MDR), by measuring the cost of acquiring streptomycin resistance mutations (StrepR) in independent strains of the bacterium Pseudomonas aeruginosa carrying different rifampicin resistance (RifR) mutations. In the absence of antibiotics, StrepR mutations are associated with similar fitness costs in different RifR genetic backgrounds. The cost of StrepR mutations is greater in a rifampicin-sensitive (RifS) background, directly demonstrating antagonistic epistasis between resistance mutations. In the presence of rifampicin, StrepR mutations have contrasting effects in different RifR backgrounds: StrepR mutations have no detectable costs in some RifR backgrounds and massive fitness costs in others. Our results clearly demonstrate the importance of epistasis and genotype-by-environment interactions for the evolution of MDR.

  12. Contribution of Stress Responses to Antibiotic Tolerance in Pseudomonas aeruginosa Biofilms

    Science.gov (United States)

    Franklin, Michael J.; Williamson, Kerry S.; Folsom, James P.; Boegli, Laura; James, Garth A.

    2015-01-01

    Enhanced tolerance of biofilm-associated bacteria to antibiotic treatments is likely due to a combination of factors, including changes in cell physiology as bacteria adapt to biofilm growth and the inherent physiological heterogeneity of biofilm bacteria. In this study, a transcriptomics approach was used to identify genes differentially expressed during biofilm growth of Pseudomonas aeruginosa. These genes were tested for statistically significant overlap, with independently compiled gene lists corresponding to stress responses and other putative antibiotic-protective mechanisms. Among the gene groups tested were those associated with biofilm response to tobramycin or ciprofloxacin, drug efflux pumps, acyl homoserine lactone quorum sensing, osmotic shock, heat shock, hypoxia stress, and stationary-phase growth. Regulons associated with Anr-mediated hypoxia stress, RpoS-regulated stationary-phase growth, and osmotic stress were significantly enriched in the set of genes induced in the biofilm. Mutant strains deficient in rpoS, relA and spoT, or anr were cultured in biofilms and challenged with ciprofloxacin and tobramycin. When challenged with ciprofloxacin, the mutant strain biofilms had 2.4- to 2.9-log reductions in viable cells compared to a 0.9-log reduction of the wild-type strain. Interestingly, none of the mutants exhibited a statistically significant alteration in tobramycin susceptibility compared to that with the wild-type biofilm. These results are consistent with a model in which multiple genes controlled by overlapping starvation or stress responses contribute to the protection of a P. aeruginosa biofilm from ciprofloxacin. A distinct and as yet undiscovered mechanism protects the biofilm bacteria from tobramycin. PMID:25870065

  13. Biosorpsi Logam Zn Pada Limbah Sintetik Menggunakan Biomassa Campuran Pseudomonas aeruginosa dan Pseudomonas sp

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    Hidayati Hidayati

    2013-12-01

    Full Text Available Zinc is one of the heavy metals that could be harmful for environment. This metal usually arises from industrial activities. Biosorption of zinc in synthetic waste was conducted using biomass mixture of Pseudomonas aeruginosa and Pseudomonas sp. This research aims to determine the zinc adsorption capacity of the biomass in synthetic waste water. Zinc biosorption was performed at pH 4, room temperature and stirring 800 rpm. Variation of contact time used was 30, 60 and 120 min; and the amount of biomass used was 0.01 g, 0.02 g, 0.03 g, 0.04 g and 0.05 g. The highest zinc biosorption capacity was obtained 25.43% at the time of 120 minutes and the amount of biomass used 0.01 g. The optimum condition for biomass biosorption and removal capacity based on the correlation between experimental data and mathematical models was obtained with the addition of 0.04 g of biomass with correlation coefficient (R 1 and 0,965 respectively.ABSTRAK Salah satu logam berat yang berbahaya dari hasil kegiatan industri adalah logam Zn (seng. Biosorpsi logam Zn pada limbah sintetik dilakukan dengan menggunakan biomassa campuran Pseudomonas aeruginosa dan Pseudomonas sp. Penelitian ini bertujuan untuk mengetahui kapasitas biomassa dalam mengadsorpsi logam Zn pada limbah sintetik. Biosorpsi logam Zn dilakukan pada kondisi pH 4, temperatur ruang dan pengadukan 800 rpm. Variasi waktu kontak dilakukan pada 30, 60 dan 120 menit  dan menggunakan jumlah biomassa 0,01 g, 0,02 g, 0,03 g, 0,04 g  dan 0,05 g. Kapasitas biosorpsi logam Zn tertinggi diperoleh sebesar 25,43% pada waktu 120 menit dengan jumlah biomassa 0,01 g. Kondisi optimum biosorpsi logam Zn berdasarkan korelasi antara data eksperimen dan model matematika diperoleh pada penambahan jumlah biomassa sebesar 0,04 g baik untuk kapasitas biosorpsi logam Zn maupun efisiensi removal logam Zn dengan nilai koefisien korelasi (R2 masing-masing adalah 1 dan 0,965.

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

    Directory of Open Access Journals (Sweden)

    Eduardo José Valença Cordeiro Pires

    2009-12-01

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

  15. Pseudomonas aeruginosa forms Biofilms in Acute InfectionIndependent of Cell-to-Cell Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Schaber, J. Andy; Triffo, W.J.; Suh, Sang J.; Oliver, Jeffrey W.; Hastert, Mary C.; Griswold, John A.; Auer, Manfred; Hamood, Abdul N.; Rumbaugh, Kendra P.

    2006-09-20

    Biofilms are bacterial communities residing within a polysaccharide matrix that are associated with persistence and antibiotic resistance in chronic infections. We show that the opportunistic pathogen Pseudomonas aeruginosa forms biofilms within 8 hours of infection in thermally-injured mice, demonstrating that biofilms contribute to bacterial colonization in acute infections. P. aeruginosa biofilms were visualized within burned tissue surrounding blood vessels and adipose cells. Although quorum sensing (QS), a bacterial signaling mechanism, coordinates differentiation of biofilms in vitro, wild type and QS-deficient P. aeruginosa formed similar biofilms in vivo. Our findings demonstrate that P. aeruginosa forms biofilms on specific host tissues independent of QS.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    James P Garnett

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

  18. Nitrogen Source Stabilization of Quorum Sensing in the Pseudomonas aeruginosa Bioaugmentation Strain SD-1.

    Science.gov (United States)

    Wang, Mei-Zhen; Lai, Bai-Min; Dandekar, Ajai A; Yang, Yu-Sheng; Li, Na; Yin, Jun; Shen, Dong-Sheng

    2017-08-15

    Pseudomonas aeruginosa SD-1 is efficient at degrading aromatic compounds and can therefore contribute to the bioremediation of wastewater. P. aeruginosa uses quorum sensing (QS) to regulate the production of numerous secreted "public goods." In wastewater bioaugmentation applications, there are myriad nitrogen sources, and we queried whether various nitrogen sources impact the stabilities of both QS and the bacterial populations. In a laboratory strain of P. aeruginosa, PAO1, the absence of a nitrogen source has been shown to destabilize these populations through the emergence of QS mutant "cheaters." We tested the ability of SD-1 to grow in casein broth, a condition that requires QS for growth, when the nitrogen source with either NH4Cl, NaNO3, or NaNO2 or with no added nitrogen source. There was great variability in susceptibility to invasion by QS mutant cheaters and, by extension, the stability of the SD-1 population. When grown with NH4Cl as an extra nitrogen source, no population collapse was observed; by contrast, two-thirds of cultures grown in the presence of NaNO2 collapsed. In the populations that collapsed, the frequency of social cheaters exceeded 40%. NaNO3 and NaNO2 directly favor QS mutants of P. aeruginosa SD-1. Although the mechanism by which these nitrogen sources act is not clear, these data indicate that the metabolism of nitrogen can affect the stability of bacterial populations, an important observation for continuing industrial applications with this species.IMPORTANCE Bioaugmentation as a method to help remediate wastewater pollutant streams holds significant potential to enhance traditional methods of treatment. Addition of microbes that can catabolize organic pollutants can be an effective method to remove several toxic compounds. Such bioaugmented strains of bacteria have been shown to be susceptible to competition from the microbiota that are present in wastewater streams, limiting their potential effectiveness. Here, we show that

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

    NARCIS (Netherlands)

    Braun, P; Bitter, W; Tommassen, J

    2000-01-01

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

  20. Intensive care unit-acquired pneumonia due to Pseudomonas aeruginosa with and without multidrug resistance.

    Science.gov (United States)

    Fernández-Barat, Laia; Ferrer, Miquel; De Rosa, Francesca; Gabarrús, Albert; Esperatti, Mariano; Terraneo, Silvia; Rinaudo, Mariano; Li Bassi, Gianluigi; Torres, Antoni

    2017-02-01

    Pseudomonas aeruginosa often presents multi-drug resistance (MDR) in intensive care unit (ICU)-acquired pneumonia (ICUAP), possibly resulting in inappropriate empiric treatment and worse outcomes. We aimed to identify patients with ICUAP at risk for these pathogens in order to improve treatment selection and outcomes. We prospectively assessed 222 consecutive immunocompetent ICUAP patients confirmed microbiologically. We determined the characteristics, risk factors, systemic inflammatory response and outcomes of P. aeruginosa pneumonia (Pa-ICUAP), compared to other aetiologies. We also compared patients with MDR vs. non-MDR Pa-ICUAP. Pseudomonas aeruginosa was the most frequent aetiology (64, 29%); 22 (34%) cases had MDR. Independent predictors for Pa-ICUAP were prior airway colonization by P. aeruginosa, previous antibiotic treatment, solid cancer and shock; alcohol abuse and pleural effusion were independently associated to lower risk for Pa-ICUAP. Chronic liver disease independently predicted MDR among Pa-ICUAP. The inflammatory biomarkers were similar between all groups. Patients with Pa-ICUAP had lower unadjusted 90-day survival (p = 0.049). However, the 90-day survival adjusted for confounding factors using a propensity score did not differ between all groups. Pseudomonas aeruginosa remains the most frequent aetiology of ICUAP, with high prevalence of MDR. These risk factors should be taken into account to avoid inappropriate empiric antibiotics for Pa-ICUAP. Pseudomonas aeruginosa, regardless multidrug resistance, was not associated with different propensity-adjusted survival. Copyright © 2016 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  1. Adaptation-based resistance to siderophore-conjugated antibacterial agents by Pseudomonas aeruginosa.

    Science.gov (United States)

    Tomaras, Andrew P; Crandon, Jared L; McPherson, Craig J; Banevicius, Mary Anne; Finegan, Steven M; Irvine, Rebecca L; Brown, Matthew F; O'Donnell, John P; Nicolau, David P

    2013-09-01

    Multidrug resistance in Gram-negative bacteria has become so threatening to human health that new antibacterial platforms are desperately needed to combat these deadly infections. The concept of siderophore conjugation, which facilitates compound uptake across the outer membrane by hijacking bacterial iron acquisition systems, has received significant attention in recent years. While standard in vitro MIC and resistance frequency methods demonstrate that these compounds are potent, broad-spectrum antibacterial agents whose activity should not be threatened by unacceptably high spontaneous resistance rates, recapitulation of these results in animal models can prove unreliable, partially because of the differences in iron availability in these different methods. Here, we describe the characterization of MB-1, a novel siderophore-conjugated monobactam that demonstrates excellent in vitro activity against Pseudomonas aeruginosa when tested using standard assay conditions. Unfortunately, the in vitro findings did not correlate with the in vivo results we obtained, as multiple strains were not effectively treated by MB-1 despite having low MICs. To address this, we also describe the development of new in vitro assays that were predictive of efficacy in mouse models, and we provide evidence that competition with native siderophores could contribute to the recalcitrance of some P. aeruginosa isolates in vivo.

  2. An orphan chemotaxis sensor regulates virulence and antibiotic tolerance in the human pathogen Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Heather Pearl McLaughlin

    Full Text Available The synthesis of virulence factors by pathogenic bacteria is highly regulated and occurs in response to diverse environmental cues. An array of two component systems (TCSs serves to link perception of different cues to specific changes in gene expression and/or bacterial behaviour. Those TCSs that regulate functions associated with virulence represent attractive targets for interference in anti-infective strategies for disease control. We have previously identified PA2572 as a putative response regulator required for full virulence of Pseudomonas aeruginosa, the opportunistic human pathogen, to Galleria mellonella (Wax moth larvae. Here we have investigated the involvement of candidate sensors for signal transduction involving PA2572. Mutation of PA2573, encoding a probable methyl-accepting chemotaxis protein, gave rise to alterations in motility, virulence, and antibiotic resistance, functions which are also controlled by PA2572. Comparative transcriptome profiling of mutants revealed that PA2572 and PA2573 regulate expression of a common set of 49 genes that are involved in a range of biological functions including virulence and antibiotic resistance. Bacterial two-hybrid analysis indicated a REC-dependent interaction between PA2572 and PA2573 proteins. Finally expression of PA2572 in the PA2573 mutant background restored virulence to G. mellonella towards wild-type levels. The findings indicate a role for the orphan chemotaxis sensor PA2573 in the regulation of virulence and antibiotic tolerance in P. aeruginosa and indicate that these effects are exerted in part through signal transduction involving PA2572.

  3. Azithromycin Modulates 3',5'-cyclic Diguanylic Acid Signaling in Pseudomonas aeruginosa.

    Science.gov (United States)

    Kimura, Soichiro; Mori, Nobuaki; Kai, Toshihiro; Ishii, Yoshikazu; Yamaguchi, Keizo; Tateda, Kazuhiro

    2017-08-01

    Macrolides have been reported to exert a variety of effects on both host immunomodulation and repression of bacterial pathogenicity. In this study, we report that the 3',5'-cyclic diguanylic acid (c-di-GMP) signaling system, which regulates virulence in Pseudomonas aeruginosa, is affected by the macrolide azithromycin. Using DNA microarray analysis, we selected a gene encoding PA2567 related to c-di-GMP metabolism that was significantly affected by azithromycin treatment. Expression of the PA2567 gene was significantly repressed by azithromycin in a time- and dose-dependent manner, whereas no difference in PA2567 gene expression was observed in the absence of azithromycin. In-frame deletion of the PA2567 gene affected both virulence factors and the quorum-sensing system, and significantly decreased total bacteria in a mouse pneumonia model compared to the wild-type strain (P < 0.05). These results suggest that macrolides possess the ability to modulate c-di-GMP intracellular signaling in P. aeruginosa. Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  4. Effect of SPLUNC1 protein on the Pseudomonas aeruginosa and Epstein-Barr virus.

    Science.gov (United States)

    Zhou, Hou-De; Li, Xiao-Ling; Li, Gui-Yuan; Zhou, Ming; Liu, Hua-Ying; Yang, Yi-Xing; Deng, Tan; Ma, Jian; Sheng, Shou-Rong

    2008-02-01

    Short palate, lung and nasal epithelium clone 1 (SPLUNC1) gene coded a secreted protein found at the surface of nasopharyngeal epithelium, which may be an innate immunity defensive molecular and a risk factor for nasopharyngeal carcinoma (NPC). Here, we observed the effects of SPLUNC1 on the Gram negative bacteria Pseudomonas aeruginosa, evaluated the ability of SPLUNC1 protein binding to lipopolysaccharide. To observe the effect of SPLUNC1 protein on Epstein-Barr virus (EBV), we raised three EBV-transformed B-lymphocyte lines and treated the cells by SPLUNC1 protein; cellular disruption, apoptosis, EBV DNA content, and viral oncogene expression were analyzed. We found that SPLUNC1 protein can bind to bacterial lipopolysaccharide, inhibit the growth of P. aeruginosa, enhance the disruption and apoptosis of EBV-infected B-lymphocytes, downregulate protein expression of EBV latent membrane protein 1, while upregulate protein expression of EBV envelope glycoprotein gp350/220. The total EBV DNA in the culture medium was decreased significantly after 7 days of treatment by SPLUNC1. This study shows that SPLUNC1 not only has the role of antibacteria and antivirus, but also inhibits the potential oncogenicity of EBV in respiratory epithelium.

  5. Synthesis of multiple Pseudomonas aeruginosa biofilm matrix exopolysaccharides is post-transcriptionally regulated.

    Science.gov (United States)

    Ma, Luyan; Wang, Juan; Wang, Shiwei; Anderson, Erin M; Lam, Joseph S; Parsek, Matthew R; Wozniak, Daniel J

    2012-08-01

    Exopolysaccharide is a critical biofilm matrix component, yet little is known about how the synthesis of multiple exopolysaccharides is regulated. Pseudomonas aeruginosa can produce several biofilm matrix exopolysaccharides that include alginate, Psl and Pel. Here we demonstrated that AlgC, a key enzyme that provides sugar precursors for the synthesis of alginate and lipopolysaccharides (LPS) is also required for both Psl and Pel production. We showed that forced-synthesis of Psl in alginate-producing mucoid bacteria reduced alginate production but this was not due to transcription of the alginate biosynthesis-operon. Likewise, when either alginate or Psl were overproduced, levels of B-band LPS decreased. Induction of Pel resulted in a reduction of Psl levels. Because the effects of reduced exopolysaccharide synthesis when another is overproduced didn't appear to be regulated at the transcriptional level, this suggests that the biosynthesis pathways of Psl, Pel, alginate, and LPS compete for common sugar precursors. As AlgC is the only enzyme that provides precursors for each of these exopolysaccharides, we propose that AlgC is a key checkpoint enzyme that coordinates the total amount of exopolysaccharide biosynthesis by controlling sugar precursor pool. Our data also provide a plausible strategy that P.aeruginosa utilizes to modulate its biofilm matrix exopolysaccharides. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  6. Influence of aptamer-targeted antibiofilm agents for treatment of Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Wang, Sheng; Mao, Biyao; Wu, Mingxi; Liang, Jingjing; Deng, Le

    2018-02-01

    Biofilms are bacterial communities consisting of numerous extracellular polymeric substances. Infections caused by biofilm-forming bacteria are considered to be a major threat to health security and so novel approaches to control biofilm are of importance. Aptamers are single-strand nucleic acid molecules that have high selectivity to their targets. Single-walled carbon nanotubes (SWNTs) are common nanomaterials and have been shown to be toxic to bacterial biofilms. The aim of this study was to test whether an aptamer could play a role as targeting agents to enhance the efficiency of anti-biofilm agents. Hence, two complexes (aptamer-SWNTs and aptamer-ciprofloxacin-SWNTs) based on an aptamer which targets Pseudomonas aeruginosa and SWNTs were constructed. Both complexes were assessed against P. aeruginosa biofilms. In vitro tests demonstrated that the aptamer-SWNTs could inhibit ~36% more biofilm formation than SWNTs alone. Similarly, the aptamer-ciprofloxacin-SWNTs had a higher anti-biofilm efficiency than either component or simple mixtures of two components. Our study underscores the potential of aptamers as targeting agents for anti-biofilm compounds, as well as providing a new strategy to control biofilms.

  7. Transcriptome analysis of Pseudomonas aeruginosa PAO1 grown at both body and elevated temperatures

    Directory of Open Access Journals (Sweden)

    Kok-Gan Chan

    2016-07-01

    Full Text Available Functional genomics research can give us valuable insights into bacterial gene function. RNA Sequencing (RNA-seq can generate information on transcript abundance in bacteria following abiotic stress treatments. In this study, we used the RNA-seq technique to study the transcriptomes of the opportunistic nosocomial pathogen Pseudomonas aeruginosa PAO1 following heat shock. Samples were grown at both the human body temperature (37 °C and an arbitrarily-selected temperature of 46 °C. In this work using RNA-seq, we identified 133 genes that are differentially expressed at 46 °C compared to the human body temperature. Our work identifies some key P. aeruginosa PAO1 genes whose products have importance in both environmental adaptation as well as in vivo infection in febrile hosts. More importantly, our transcriptomic results show that many genes are only expressed when subjected to heat shock. Because the RNA-seq can generate high throughput gene expression profiles, our work reveals many unanticipated genes with further work to be done exploring such genes products.

  8. Selection of Functional Quorum Sensing Systems by Lysogenic Bacteriophages in Pseudomonas aeruginosa.

    Science.gov (United States)

    Saucedo-Mora, Miguel A; Castañeda-Tamez, Paulina; Cazares, Adrián; Pérez-Velázquez, Judith; Hense, Burkhard A; Cazares, Daniel; Figueroa, Wendy; Carballo, Marco; Guarneros, Gabriel; Pérez-Eretza, Berenice; Cruz, Nelby; Nishiyama, Yoshito; Maeda, Toshinari; Belmont-Díaz, Javier A; Wood, Thomas K; García-Contreras, Rodolfo

    2017-01-01

    Quorum sensing (QS) in Pseudomonas aeruginosa coordinates the expression of virulence factors, some of which are used as public goods. Since their production is a cooperative behavior, it is susceptible to social cheating in which non-cooperative QS deficient mutants use the resources without investing in their production. Nevertheless, functional QS systems are abundant; hence, mechanisms regulating the amount of cheating should exist. Evidence that demonstrates a tight relationship between QS and the susceptibility of bacteria against the attack of lytic phages is increasing; nevertheless, the relationship between temperate phages and QS has been much less explored. Therefore, in this work, we studied the effects of having a functional QS system on the susceptibility to temperate bacteriophages and how this affects the bacterial and phage dynamics. We find that both experimentally and using mathematical models, that the lysogenic bacteriophages D3112 and JBD30 select QS-proficient P. aeruginosa phenotypes as compared to the QS-deficient mutants during competition experiments with mixed strain populations in vitro and in vivo in Galleria mellonella, in spite of the fact that both phages replicate better in the wild-type background. We show that this phenomenon restricts social cheating, and we propose that temperate phages may constitute an important selective pressure toward the conservation of bacterial QS.

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

    Science.gov (United States)

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

    2014-05-14

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

  10. Selection of Functional Quorum Sensing Systems by Lysogenic Bacteriophages in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Miguel A. Saucedo-Mora

    2017-08-01

    Full Text Available Quorum sensing (QS in Pseudomonas aeruginosa coordinates the expression of virulence factors, some of which are used as public goods. Since their production is a cooperative behavior, it is susceptible to social cheating in which non-cooperative QS deficient mutants use the resources without investing in their production. Nevertheless, functional QS systems are abundant; hence, mechanisms regulating the amount of cheating should exist. Evidence that demonstrates a tight relationship between QS and the susceptibility of bacteria against the attack of lytic phages is increasing; nevertheless, the relationship between temperate phages and QS has been much less explored. Therefore, in this work, we studied the effects of having a functional QS system on the susceptibility to temperate bacteriophages and how this affects the bacterial and phage dynamics. We find that both experimentally and using mathematical models, that the lysogenic bacteriophages D3112 and JBD30 select QS-proficient P. aeruginosa phenotypes as compared to the QS-deficient mutants during competition experiments with mixed strain populations in vitro and in vivo in Galleria mellonella, in spite of the fact that both phages replicate better in the wild-type background. We show that this phenomenon restricts social cheating, and we propose that temperate phages may constitute an important selective pressure toward the conservation of bacterial QS.

  11. Head-out spirometry accurately monitors the course of Pseudomonas aeruginosa lung infection in mice.

    Science.gov (United States)

    Wölbeling, Florian; Munder, Antje; Stanke, Frauke; Tümmler, Burkhard; Baumann, Ulrich

    2010-01-01

    Classic infection models in rodents use lethal doses of bacteria as inocula, thus creating models which are rarely comparable to the clinical situation. Moreover, single time-point evaluation requires killing of the animals, necessitating large numbers of animals. Longitudinal parameters such as temperature appear to have a relatively low accuracy. Spirometry might be an accurate method to assess the course of a bacterial lung infection without the necessity to sacrifice the animals. We measured lung function in C57BL/6JZtm mice following intratracheal infection with Pseudomonas aeruginosa and compared it to physiological parameters and lung histology. Head-out spirometry measuring 14 parameters was performed on C57BL6/J mice for eight days following a P. aeruginosa lung infection. Additionally rectal temperature, body weight and condition were assessed together with histological data and bacteriological clearance. Several spirometric parameters were significantly altered for more than 72 h after inoculation, which was four times longer than observed alterations in physiological parameters such as temperature. Volume (amount of air inspired) decreased more than seven-fold within 6 h after inoculation and required 72 h to recover, rendering it the most sensitive spirometric parameter investigated. Spirometric and histological data correlated well. Our findings suggest that non-invasive head-out spirometry is a reliable and highly sensitive method to longitudinally assess the course of bacterial lung infections. Copyright © 2010 S. Karger AG, Basel.

  12. Gene PA2449 is essential for glycine metabolism and pyocyanin biosynthesis in Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Lundgren, Benjamin R; Thornton, William; Dornan, Mark H; Villegas-Peñaranda, Luis Roberto; Boddy, Christopher N; Nomura, Christopher T

    2013-05-01

    Many pseudomonads produce redox active compounds called phenazines that function in a variety of biological processes. Phenazines are well known for their toxicity against non-phenazine-producing organisms, which allows them to serve as crucial biocontrol agents and virulence factors during infection. As for other secondary metabolites, conditions of nutritional stress or limitation stimulate the production of phenazines, but little is known of the molecular details underlying this phenomenon. Using a combination of microarray and metabolite analyses, we demonstrate that the assimilation of glycine as a carbon source and the biosynthesis of pyocyanin in Pseudomonas aeruginosa PAO1 are both dependent on the PA2449 gene. The inactivation of the PA2449 gene was found to influence the transcription of a core set of genes encoding a glycine cleavage system, serine hydroxymethyltransferase, and serine dehydratase. PA2449 also affected the transcription of several genes that are integral in cell signaling and pyocyanin biosynthesis in P. aeruginosa PAO1. This study sheds light on the unexpected relationship between the utilization of an unfavorable carbon source and the production of pyocyanin. PA2449 is conserved among pseudomonads and might be universally involved in the assimilation of glycine among this metabolically diverse group of bacteria.

  13. Steady-state hydrogen peroxide induces glycolysis in Staphylococcus aureus and Pseudomonas aeruginosa.

    Science.gov (United States)

    Deng, Xin; Liang, Haihua; Ulanovskaya, Olesya A; Ji, Quanjiang; Zhou, Tianhong; Sun, Fei; Lu, Zhike; Hutchison, Alan L; Lan, Lefu; Wu, Min; Cravatt, Benjamin F; He, Chuan

    2014-07-01

    Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from human pathogens Staphylococcus aureus and Pseudomonas aeruginosa can be readily inhibited by reactive oxygen species (ROS)-mediated direct oxidation of their catalytic active cysteines. Because of the rapid degradation of H2O2 by bacterial catalase, only steady-state but not one-dose treatment with H2O2 rapidly induces glycolysis and the pentose phosphate pathway (PPP). We conducted transcriptome sequencing (RNA-seq) analyses to globally profile the bacterial transcriptomes in response to a steady level of H2O2, which revealed profound transcriptional changes, including the induced expression of glycolytic genes in both bacteria. Our results revealed that the inactivation of GAPDH by H2O2 induces metabolic levels of glycolysis and the PPP; the elevated levels of fructose 1,6-biphosphate (FBP) and 2-keto-3-deoxy-6-phosphogluconate (KDPG) lead to dissociation of their corresponding glycolytic repressors (GapR and HexR, respectively) from their cognate promoters, thus resulting in derepression of the glycolytic genes to overcome H2O2-stalled glycolysis in S. aureus and P. aeruginosa, respectively. Both GapR and HexR may directly sense oxidative stresses, such as menadione. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  14. Effects of combined treatment with ambroxol and ciprofloxacin on catheter-associated Pseudomonas aeruginosa biofilms in a rat model.

    Science.gov (United States)

    Lu, Qi; Yu, JiaLin; Bao, Lei; Ran, Tao; Zhong, Haiying

    2013-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that causes potentially devastating infections in immunocompromised patients. These infections are particularly difficult to treat if a biofilm forms, which is likely if foreign bodies are present. This study aimed to investigate the effect of ambroxol combined with ciprofloxacin on P. aeruginosa biofilm in a rat model. A rat model of acute lung infection was created by endotracheal (ET) intubation with a tube covered with a P. aeruginosa biofilm. The rats were treated with ciprofloxacin alone, ambroxol alone, or a combination of both for 7 days. The microstructure of the biofilm on the tube was assessed by scanning electron microscopy (SEM). The numbers of bacterial colonies in the lungs and on the ET tube were measured on agar plates. Pathological changes in the lungs were observed with hematoxylin and eosin staining. Changes in the microstructure of the biofilm after combined treatment were demonstrated by SEM. Ambroxol combined with ciprofloxacin significantly reduced the number of bacteria in the lungs and ET tube compared to the single treatments (p ambroxol with ciprofloxacin has a high ability to eradicate P. aeruginosa biofilms in vivo. These initial results provide the basis of a new strategy for the treatment of P. aeruginosa infections. Copyright © 2013 S. Karger AG, Basel.

  15. Agaricus Blazei Hot Water Extract Shows Anti Quorum Sensing Activity in the Nosocomial Human Pathogen Pseudomonas Aeruginosa

    Directory of Open Access Journals (Sweden)

    Marina Soković

    2014-04-01

    Full Text Available The edible mushroom Agaricus blazei Murill is known to induce protective immunomodulatory action against a variety of infectious diseases. In the present study we report potential anti-quorum sensing properties of A. blazei hot water extract. Quorum sensing (QS plays an important role in virulence, biofilm formation and survival of many pathogenic bacteria, including the Gram negative Pseudomonas aeruginosa, and is considered as a novel and promising target for anti-infectious agents. In this study, the effect of the sub-MICs of Agaricus blazei water extract on QS regulated virulence factors and biofilm formation was evaluated against P. aeruginosa PAO1. Sub-MIC concentrations of the extract which did not kill P. aeruginosa nor inhibited its growth, demonstrated a statistically significant reduction of virulence factors of P. aeruginosa, such as pyocyanin production, twitching and swimming motility. The biofilm forming capability of P. aeruginosa was also reduced in a concentration-dependent manner at sub-MIC values. Water extract of A. blazei is a promising source of antiquorum sensing and antibacterial compounds.

  16. Community-acquired Pseudomonas aeruginosa-pneumonia in a previously healthy man occupationally exposed to metalworking fluids

    Directory of Open Access Journals (Sweden)

    Fernando Peixoto Ferraz de Campos

    2014-09-01

    Full Text Available Although the Pseudomonas aeruginosa infection is well known and frequently found in hospitals and nursing care facilities, many cases are also reported outside these boundaries. In general, this pathogen infects debilitated patients either by comorbidities or by any form of immunodeficiency. In cases of respiratory infection, tobacco abuse seems to play an important role as a risk factor. In previously healthy patients, community-acquired pneumonia (CAP with P. aeruginosa as the etiological agent is extremely rare, and unlike the cases involving immunocompromised or hospitalized patients, the outcome is severe, and is fatal in up to 61.1% of cases. Aerosolized contaminated water or solutions are closely linked to the development of respiratory tract infection. In this setting, metalworking fluids used in factories may be implicated in CAP involving previously healthy people. The authors report the case of a middle-aged man who worked in a metalworking factory and presented a right upper lobar pneumonia with a rapid fatal outcome. P. aeruginosa was cultured from blood and tracheal aspirates. The autopsy findings confirmed a hemorrhagic necrotizing pneumonia with bacteria-invading vasculitis and thrombosis. A culture of the metalworking fluid of the factory was also positive for P. aeruginosa. The pulsed-field gel electrophoresis showed that both strains (blood culture and metalworking fluid were genetically indistinguishable. The authors highlight the occupational risk for the development of this P. aeruginosa-infection in healthy people.

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

    Directory of Open Access Journals (Sweden)

    Azadeh eRahmani-Badi

    2015-04-01

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

  18. Antibiotic resistance profile of Pseudomonas aeruginosa isolated from aquaculture and abattoir environments in urban communities

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    Isoken Henrietta Igbinosa

    2017-01-01

    Full Text Available Objective: To characterize multiple antibiotic resistance profile of Pseudomonas aeruginosa from aquaculture and abattoir environments. Methods: Wastewater samples were obtained from the abattoir and aquaculture environments between May 2016 and July 2016 and analysed using standard phenotypic, biochemical and PCR-based methods. Results: The mean pseudomonads count ranged from (4 × 102 ± 1.01 to (2 × 104 ± 0.10 colony-forming unit/mL in the aquaculture environment and (3 × 103 ± 0.00 to (1 × 105 ± 1.00 colony-forming unit/mL in the abattoir environment. A total of 96 isolates of Pseudomonas aeruginosa confirmed by PCR were thereafter selected from both aquaculture and abattoir environments and further characterized for their antimicrobial susceptibility profile by adopting the disc diffusion method. High level of resistance was observed against the aminoglycosides [gentamycin 64/96 (66.67% and kanamycin 52/96 (54.17%], monobactams [aztreonam 76/96 (79.17%], carbapenems [meropenem 52/96 (54.17%], tetracyclines [tetracycline 72/96 (75.00%] and cephems [ceftazidime 72/96 (75.00% and cefuroxime 48/96 (50.00%]. Multiple antibiotic resistant index of the respective isolates ranged from 0.4 to 0.8 while multidrug resistant profile of the isolates revealed that 28 of the respective isolates were resistant to ceftazidime, cefuroxime, gentamycin, kanamycin, aztreonam which belongs to cephems, aminoglycosides and monobactam class of antimicrobials. Conclusions: Findings from the present study therefore underscores the need for effective monitoring of the abattoir and aquaculture environments as they could be the significant source for spreading antibiotic resistant bacteria within the environment.

  19. Endoftalmitis posvitrectomía por Pseudomona aeruginosa

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    Violeta Rodríguez Rodríguez

    Full Text Available Se describe el caso de un paciente varón de 22 años, miope, sometido a vitrectomía pars plana 23 G en ojo único (valioso, por desprendimiento de retina regmatógeno. A las 24 horas presentó pérdida de visión, dolor, signos inflamatorios en globo y anejos oculares. Acudió al Servicio de Emergencias, donde se decidió su ingreso hospitalario para la toma de muestra y la aplicación de inyección intravítrea de vancomicina (1 mg/0,1 mL y ceftazidima (2 mg/0,1 mL, con lo que mostró mejoría clínica. El estudio microbiológico reportó Pseudomona aeruginosa sensible a la ceftazidima y a la ciprofloxacina. La mejor visualización fundoscópica al quinto día posintravítrea permitió observar depósitos blanquecinos en la interfaz aceite de silicona-retina, y se decidió la extracción de aceite por incisiones mixtas 23 g y 20 g (infusión, endoiluminación y extracción respectivamente, lavado de cámara anterior, cámara vítrea, reposición de aceite de silicón y segunda dosis de ceftazidima, con evolución posoperatoria favorable. Se dio el alta una semana después, con la retina aplicada y una mejor visión corregida de 0,1.

  20. Isolation and characterization of gallium resistant Pseudomonas aeruginosa mutants.

    Science.gov (United States)

    García-Contreras, Rodolfo; Lira-Silva, Elizabeth; Jasso-Chávez, Ricardo; Hernández-González, Ismael L; Maeda, Toshinari; Hashimoto, Takahiro; Boogerd, Fred C; Sheng, Lili; Wood, Thomas K; Moreno-Sánchez, Rafael

    2013-12-01

    Pseudomonas aeruginosa PA14 cells resistant to the novel antimicrobial gallium nitrate (Ga) were developed using transposon mutagenesis and by selecting spontaneous mutants. The mutants showing the highest growth in the presence of Ga were selected for further characterization. These mutants showed 4- to 12-fold higher Ga minimal inhibitory growth concentrations and a greater than 8-fold increase in the minimum biofilm eliminating Ga concentration. Both types of mutants produced Ga resistant biofilms whereas the formation of wild-type biofilms was strongly inhibited by Ga. The gene interrupted in the transposon mutant was hitA, which encodes a periplasmic iron binding protein that delivers Fe³⁺ to the HitB iron permease; complementation of the mutant with the hitA gene restored the Ga sensitivity. This hitA mutant showed a 14-fold decrease in Ga internalization versus the wild-type strain, indicating that the HitAB system is also involved in the Ga uptake. Ga uptake in the spontaneous mutant was also lower, although no mutations were found in the hitAB genes. Instead, this mutant harbored 64 non-silent mutations in several genes including those of the phenazine pyocyanin biosynthesis. The spontaneous mutant produced 2-fold higher pyocyanin basal levels than the wild-type; the addition of this phenazine to wild-type cultures protected them from the Ga bacteriostatic effect. The present data indicate that mutations affecting Ga transport and probably pyocyanin biosynthesis enable cells to develop resistance to Ga. Copyright © 2013 Elsevier GmbH. All rights reserved.

  1. Molecular Determinants of the Thickened Matrix in a Dual-Species Pseudomonas aeruginosa and Enterococcus faecalis Biofilm.

    Science.gov (United States)

    Lee, Keehoon; Lee, Kang-Mu; Kim, Donggeun; Yoon, Sang Sun

    2017-11-01

    reported that microbes in polymicrobial biofilms interact with each other and that the bacterial interactions result in elevated virulence, in terms of factors, such as infectivity and antibiotic resistance. Pseudomonas aeruginosa and Enterococcus faecalis are frequently isolated pathogens in chronic biofilm infections. Nevertheless, while both bacteria are known to be agents of numerous nosocomial infections and can cause serious diseases, interactions between the bacteria in biofilms have rarely been examined. In this investigation, we aimed to characterize P. aeruginosa and E. faecalis dual-species biofilms and to determine the molecular factors that cause synergistic effects, especially on the matrix thickening of the biofilm. We suspect that our findings will contribute to the development of more efficient methods for eradicating polymicrobial biofilm infections. Copyright © 2017 American Society for Microbiology.

  2. Improved outcome of chronic Pseudomonas aeruginosa lung infection is associated with induction of a Th1-dominated cytokine response

    DEFF Research Database (Denmark)

    Moser, C; Jensen, P O; Kobayashi, O

    2002-01-01

    Repeated challenge with antigen is involved in the pathogenesis of a variety of pulmonary diseases. Patients with cystic fibrosis (CF) experience recurrent pulmonary colonization with Pseudomonas aeruginosa before establishment of chronic lung infection. To mimic recurrent lung infections in CF...... for improved clearance of bacteria, was observed when compared with singly-infected mice. The improved outcome in re-infected mice correlated with changes in CD4 cell numbers. Surface expression of LFA-1 on pulmonary CD4 cells was increased in re-infected compared with singly-infected mice. Moreover...

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

    Science.gov (United States)

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

    2016-09-01

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

  4. Assessing phage therapy against Pseudomonas aeruginosa using a Galleria mellonella infection model.

    Science.gov (United States)

    Beeton, M L; Alves, D R; Enright, M C; Jenkins, A T A

    2015-08-01

    The Galleria mellonella infection model was used to assess the in vivo efficacy of phage therapy against laboratory and clinical strains of Pseudomonas aeruginosa. In a first series of experiments, Galleria were infected with the laboratory strain P. aeruginosa PAO1 and were treated with varying multiplicity of infection (MOI) of phages either 2h post-infection (treatment) or 2h pre-infection (prevention) via injection into the haemolymph. To address the kinetics of infection, larvae were bled over a period of 24h for quantification of bacteria and phages. Survival rates at 24h when infected with 10 cells/larvae were greater in the prevention versus treatment model (47% vs. 40%, MOI=10; 47% vs. 20%, MOI=1; and 33% vs. 7%, MOI=0.1). This pattern held true when 100 cells/larvae were used (87% vs. 20%, MOI=10; 53% vs. 13%, MOI=1; 67% vs. 7%, MOI=0.1). By 24h post-infection, phages kept bacterial cell numbers in the haemolymph 1000-fold lower than in the non-treated group. In a second series of experiments using clinical strains to further validate the prevention model, phages protected Galleria when infected with both a bacteraemia (0% vs. 85%) and a cystic fibrosis (80% vs. 100%) isolate. Therefore, this study validates the use of G. mellonella as a simple, robust and cost-effective model for initial in vivo examination of P. aeruginosa-targeted phage therapy, which may be applied to other pathogens with similarly low infective doses. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  5. Prevention of bloodstream infections by photodynamic inactivation of multiresistant Pseudomonas aeruginosa in burn wounds

    Science.gov (United States)

    Hashimoto, M. C. E.; Prates, R. A.; Toffoli, D. J.; Courrol, L. C.; Ribeiro, M. S.

    2010-02-01

    Bloodstream infections are potentially life-threatening diseases. They can cause serious secondary infections, and may result in endocarditis, severe sepsis or toxic-shock syndrome. Pseudomonas aeruginosa is an opportunistic pathogen and one of the most important etiological factors responsible for nosocomial infections, mainly in immuno-compromissed hosts, characteristic of patients with severe burns. Its multiresistance to antibiotics produces many therapeutic problems, and for this reason, the development of an alternative method to antibiotic therapy is needed. Photodynamic inactivation (PDI) may be an effective and alternative therapeutic option to prevent bloodstream infections in patients with severe burns. In this study we report the use of PDI to prevent bloodstream infections in mice with third-degree burns. Burns were produced on the back of the animals and they were infected with 109 cfu/mL of multi-resistant (MR) P. aeruginosa. Fifteen animals were divided into 3 groups: control, PDT blue and PDT red. PDT was performed thirty minutes after bacterial inoculation using 10μM HB:La+3 and a light-emitting diode (LED) emitting at λ=460nm+/-20nm and a LED emitting at λ=645 nm+/-10nm for 120s. Blood of mice were colected at 7h, 10h, 15h, 18h and 22h pos-infection (p.i.) for bacterial counting. Control group presented 1×104 cfu/mL in bloodstream at 7h p.i. increasing to 1×106 at 22h, while mice PDT-treated did not present any bacteria at 7h; only at 22h p.i. they presented 1×104cfu/mL. These results suggest that HB:La+3 associated to blue LED or red LED is effective to delay and diminish MR P.aeruginosa bloodstream invasion in third-degree-burned mice.

  6. Detection of NDM-2-producing Acinetobacter baumannii and VIM-producing Pseudomonas aeruginosa in Palestine.

    Science.gov (United States)

    Sjölander, Isabella; Hansen, Frank; Elmanama, Abdelraouf; Khayyat, Rasha; Abu-Zant, Alaeddin; Hussein, Ayman; Taha, Adham Abu; Hammerum, Anette M; Ciofu, Oana

    2014-06-01

    The aim of this study was to screen for carbapenem-resistant Gram-negative bacteria in Palestine and subsequently to identify and investigate the mechanisms of resistance. For a period of 6 weeks, all Gram-negative isolates were collected from six Palestinian hospital laboratories and were tested for susceptibility using 10μg meropenem disks. Isolates showing resistance to meropenem were further investigated. The presence of carbapenemases was assessed by PCR. In addition, antimicrobial susceptibility testing, an efflux pump inhibitor assay and pulsed-field gel electrophoresis (PFGE) were performed. Isolates producing carbapenemases were further investigated by multilocus sequence typing (MLST). In total, 248 Gram-negative isolates were collected from the six laboratories. Among the 248 tested isolates, 15 Acinetobacter baumannii and 6 Pseudomonas aeruginosa were resistant to meropenem. One A. baumannii from Gaza produced NDM-2 and belonged to ST103. Thirteen of the carbapenem-resistant A. baumannii isolates possessed the intrinsic upregulated blaOXA-66 gene and one isolate carried blaOXA-51. All but one of the OXA-66-producing A. baumannii belonged to ST2; the remaining isolate belonged to ST183. One of the carbapenem-resistant P. aeruginosa was classified as VIM-4-producing and three were VIM-2-producing isolates. The three VIM-2-producing isolates belonged to three new sequences types (ST1562, ST1563 and ST1564). All of the carbapenemase-producing isolates were multiresistant non-fermenters. To the best of our knowledge, this is the first report on NDM-producing A. baumannii and VIM-producing P. aeruginosa from Palestine. Copyright © 2013 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

  7. Molecular characterization of metallo β-lactamase producing multidrug resistant Pseudomonas aeruginosa from various clinical samples.

    Science.gov (United States)

    Ramakrishnan, Kalaivani; Rajagopalan, Saranathan; Nair, Shashikala; Kenchappa, Prashanth; Chandrakesan, Sheela Devi

    2014-01-01

    Pseudomonas aeruginosa is a potent opportunistic nosocomial human pathogen among Gram-negative bacteria causing various life-threatening infections in patients from Intensive Care Units. This bacterium has become resistant to almost all commonly available antibiotics with limited treatment options. Multi drug resistant P. aeruginosa (MDRPA) is a major cause of concern among hospital acquired infections. It uses distinctive resistant mechanisms virtually to all the available antibiotics such as Metallo β-lactamases (MBL) production, extended spectrum β-lactamase production (ESBL), up regulation of efflux systems related genes and decreased outer membrane permeability. This study was carried out to find one the predominant resistance mechanisms among MDRPA and the prevalence of corresponding resistance genes. MDRPA isolates collected from various clinical samples for a period of 1-year (November 2009-Octo ber 2010) were included to detect the predominant mechanism of resistance using phenotypic and molecular methods. Molecular characterization of all these isolates was done by polymerase chain reaction (PCR) for the presence of blaVIM-₂, blaIMP-₁, blaOXA-₂₃, and blaNDM-₁ genes with specific primers. Among 75 MDRPA isolates 84% (63) were MBL producers. Molecular characterization studied by PCR showed the presence of blaVIM-₂ gene in 13% of MBL producers. The prevalence of MBLs has been increasing worldwide, particularly among P. aeruginosa, leading to severe limitations in the therapeutic options for the management. Thus, proper resistance screening measures and appropriate antibiotic policy can be strictly adopted by all the healthcare facility providers to overcome these superbugs.

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

    Science.gov (United States)

    Kazemian, Hossein; Ghafourian, Sobhan; Heidari, Hamid; Amiri, Pouya; Yamchi, Jalil Kardan; Shavalipour, Aref; Houri, Hamidreza; Maleki, Abbas; Sadeghifard, Nourkhoda

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Hossein Kazemian

    2015-08-01

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

  10. Evaluation of antibiotic effects on Pseudomonas aeruginosa biofilm using Raman spectroscopy and multivariate analysis.

    Science.gov (United States)

    Jung, Gyeong Bok; Nam, Seong Won; Choi, Samjin; Lee, Gi-Ja; Park, Hun-Kuk

    2014-09-01

    We investigate the mode of action and classification of antibiotic agents (ceftazidime, patulin, and epigallocatechin gallate; EGCG) on Pseudomonas aeruginosa (P. aeruginosa) biofilm using Raman spectroscopy with multivariate analysis, including support vector machine (SVM) and principal component analysis (PCA). This method allows for quantitative, label-free, non-invasive and rapid monitoring of biochemical changes in complex biofilm matrices with high sensitivity and specificity. In this study, the biofilms were grown and treated with various agents in the microfluidic device, and then transferred onto gold-coated substrates for Raman measurement. Here, we show changes in biochemical properties, and this technology can be used to distinguish between changes induced in P. aeruginosa biofilms using three antibiotic agents. The Raman band intensities associated with DNA and proteins were decreased, compared to control biofilms, when the biofilms were treated with antibiotics. Unlike with exposure to ceftazidime and patulin, the Raman spectrum of biofilms exposed to EGCG showed a shift in the spectral position of the CH deformation stretch band from 1313 cm(-1) to 1333 cm(-1), and there was no difference in the band intensity at 1530 cm(-1) (C = C stretching, carotenoids). The PCA-SVM analysis results show that antibiotic-treated biofilms can be detected with high sensitivity of 93.33%, a specificity of 100% and an accuracy of 98.33%. This method also discriminated the three antibiotic agents based on the cellular biochemical and structural changes induced by antibiotics with high sensitivity and specificity of 100%. This study suggests that Raman spectroscopy with PCA-SVM is potentially useful for the rapid identification and classification of clinically-relevant antibiotics of bacteria biofilm. Furthermore, this method could be a powerful approach for the development and screening of new antibiotics.

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

    Directory of Open Access Journals (Sweden)

    Mansouri, S.

    2013-01-01

    Full Text Available Aims: Pseudomonas aeruginosa is a drug resistance opportunistic bacterium. Biofilm formation is key factor for survivalof P. aeruginosa in various environments. Polysaccharides may be involved in biofilm formation. The purpose of thisstudy was to evaluate antimicrobial and anti-biofilm activities of seven plant extracts with known alpha-glucosidaseinhibitory activities on different strains of P. aeruginosa.Methodology and results: Plants were extracted with methanol by the maceration method. Antimicrobial activities weredetermined by agar dilution and by growth yield as measured by OD560nm of the Luria Bertani broth (LB culture with orwithout extracts. In agar dilution method, extracts of Quercus infectoria inhibited the growth of all, while Myrtuscommunis extract inhibited the growth of 3 out of 8 bacterial strains with minimum inhibitory concentration (MIC of 1000μg/mL. All extracts significantly (p≤0.003 reduced growth rate of the bacteria in comparison with the control withoutextracts in LB broth at sub-MIC concentrations (500 μg/mL. All plant extracts significantly (p≤0.003 reduced biofilmformation compared to the controls. Glycyrrhiza glabra and Q. infectoria had the highest anti-biofilm activities. Nocorrelation between the alpha-glucosidase inhibitory activity with growth or the intensity of biofilm formation was found.Conclusion, significance and impact of study: Extracts of Q. infectoria and M. communis had the most antimicrobial,while Q. infectoria and G. glabra had the highest anti-biofilm activities. All plant extracts had anti-biofilm activities withmarginal effect on growth, suggesting that the mechanisms of these activities are unrelated to static or cidal effects.Further work to understand the relation between antimicrobial and biofilm formation is needed for development of newmeans to fight the infectious caused by this bacterium in future.

  12. A Microfluidic Channel Method for Rapid Drug-Susceptibility Testing of Pseudomonas aeruginosa

    Science.gov (United States)

    Matsumoto, Yoshimi; Grushnikov, Andrey; Kikuchi, Kazuma; Noji, Hiroyuki; Yamaguchi, Akihito; Yagi, Yasushi

    2016-01-01

    The recent global increase in the prevalence of antibiotic-resistant bacteria and lack of development of new therapeutic agents emphasize the importance of selecting appropriate antimicrobials for the treatment of infections. However, to date, the development of completely accelerated drug susceptibility testing methods has not been achieved despite the availability of a rapid identification method. We proposed an innovative rapid method for drug susceptibility testing for Pseudomonas aeruginosa that provides results within 3 h. The drug susceptibility testing microfluidic (DSTM) device was prepared using soft lithography. It consisted of five sets of four microfluidic channels sharing one inlet slot, and the four channels are gathered in a small area, permitting simultaneous microscopic observation. Antimicrobials were pre-introduced into each channel and dried before use. Bacterial suspensions in cation-adjusted Mueller–Hinton broth were introduced from the inlet slot and incubated for 3 h. Susceptibilities were microscopically evaluated on the basis of differences in cell numbers and shapes between drug-treated and control cells, using dedicated software. The results of 101 clinically isolated strains of P. aeruginosa obtained using the DSTM method strongly correlated with results obtained using the ordinary microbroth dilution method. Ciprofloxacin, meropenem, ceftazidime, and piperacillin caused elongation in susceptible cells, while meropenem also induced spheroplast and bulge formation. Morphological observation could alternatively be used to determine the susceptibility of P. aeruginosa to these drugs, although amikacin had little effect on cell shape. The rapid determination of bacterial drug susceptibility using the DSTM method could also be applicable to other pathogenic species, and it could easily be introduced into clinical laboratories without the need for expensive instrumentation. PMID:26872134

  13. A Microfluidic Channel Method for Rapid Drug-Susceptibility Testing of Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Yoshimi Matsumoto

    Full Text Available The recent global increase in the prevalence of antibiotic-resistant bacteria and lack of development of new therapeutic agents emphasize the importance of selecting appropriate antimicrobials for the treatment of infections. However, to date, the development of completely accelerated drug susceptibility testing methods has not been achieved despite the availability of a rapid identification method. We proposed an innovative rapid method for drug susceptibility testing for Pseudomonas aeruginosa that provides results within 3 h. The drug susceptibility testing microfluidic (DSTM device was prepared using soft lithography. It consisted of five sets of four microfluidic channels sharing one inlet slot, and the four channels are gathered in a small area, permitting simultaneous microscopic observation. Antimicrobials were pre-introduced into each channel and dried before use. Bacterial suspensions in cation-adjusted Mueller-Hinton broth were introduced from the inlet slot and incubated for 3 h. Susceptibilities were microscopically evaluated on the basis of differences in cell numbers and shapes between drug-treated and control cells, using dedicated software. The results of 101 clinically isolated strains of P. aeruginosa obtained using the DSTM method strongly correlated with results obtained using the ordinary microbroth dilution method. Ciprofloxacin, meropenem, ceftazidime, and piperacillin caused elongation in susceptible cells, while meropenem also induced spheroplast and bulge formation. Morphological observation could alternatively be used to determine the susceptibility of P. aeruginosa to these drugs, although amikacin had little effect on cell shape. The rapid determination of bacterial drug susceptibility using the DSTM method could also be applicable to other pathogenic species, and it could easily be introduced into clinical laboratories without the need for expensive instrumentation.

  14. Transcriptomic and Metabolomic Analysis Revealed Multifaceted Effects of Phage Protein Gp70.1 on Pseudomonas aeruginosa

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    Xia Zhao

    2016-09-01

    Full Text Available The impact of phage infection on the host cell is severe. In order to take over the cellular machinery, some phage proteins were produced to shut off the host biosynthesis early in the phage infection. The discovery and identification of these phage-derived inhibitors have a significant prospect of application in antibacterial treatment. This work presented a phage protein, gp70.1, with nonspecific inhibitory effects on Pseudomonas aeruginosa (P. aeruginosa and Escherichia coli (E. coli. Gp70.1 was encoded by early gene – orf 70.1 from P. aeruginosa phage PaP3. The P. aeruginosa with a plasmid encoding gp70.1 showed with delayed growth and had the appearance of a small colony. The combination of multifaceted analysis including microarray-based transcriptomic analysis, RT-qPCR, nuclear magnetic resonance (NMR spectroscopy-based metabolomics and phenotype experiments were performed to investigate the effects of gp70.1 on P. aeruginosa. A total of 178 genes of P. aeruginosa mainly involved in extracellular function and metabolism were differentially expressed in the presence of gp70.1 at 3 examined time points. Furthermore, our results indicated that gp70.1 had an extensive impact on the extracellular phenotype of P. aeruginosa, such as motility, pyocyanin, extracellular protease, polysaccharide, and cellulase. For the metabolism of P. aeruginosa, the main effect of gp70.1 was the reduction of amino acid consumption. Finally, the RNA polymerase sigma factor RpoS was identified as a potential cellular target of gp70.1. Gp70.1 was the first bacterial inhibitor identified from Pseudomonas aeruginosa phage PaP3. It was also the first phage protein that interacted with the global regulator RpoS of bacteria. Our results indicated the potential value of gp70.1 in antibacterial applications. This study preliminarily revealed the biological function of gp70.1 and provided a reference for the study of other phage genes sharing similarities with orf70.1.

  15. A case of orbital apex syndrome due to Pseudomonas aeruginosa infection

    Directory of Open Access Journals (Sweden)

    Takeshi Kusunoki

    2011-11-01

    Full Text Available Orbital apex syndrome is commonly been thought to have a poor prognosis. Many cases of this syndrome have been reported to be caused by paranasal sinus mycosis. We encountered a very rare case (60-year-old woman of sinusitis with orbital apex syndrome due to Pseudomonas aeruginosa infection. She had received insulin and dialysis for diabtes and diabetic nephropathy, moreover anticoagulants after heart by-pass surgery. She underwent endoscopic sinus operation and was treated with antibiotics, but her loss of left vision did not improve. Recently, sinusitis cases due to Pseudomonas aeruginosa were reported to be a increasing. Therefore, we should consider the possibility of Pseudomonas aeruginosa as well as mycosis as infections of the sinus, especially inpatients who are immunocompromised body.

  16. A case of orbital apex syndrome due to Pseudomonas aeruginosa infection.

    Science.gov (United States)

    Kusunoki, Takeshi; Kase, Kaori; Ikeda, Katsuhisa

    2011-09-28

    Orbital apex syndrome is commonly been thought to have a poor prognosis. Many cases of this syndrome have been reported to be caused by paranasal sinus mycosis. We encountered a very rare case (60-year-old woman) of sinusitis with orbital apex syndrome due to Pseudomonas aeruginosa infection. She had received insulin and dialysis for diabtes and diabetic nephropathy, moreover anticoagulants after heart by-pass surgery. She underwent endoscopic sinus operation and was treated with antibiotics, but her loss of left vision did not improve. Recently, sinusitis cases due to Pseudomonas aeruginosa were reported to be a increasing. Therefore, we should consider the possibility of Pseudomonas aeruginosa as well as mycosis as infections of the sinus, especially inpatients who are immunocompromised body.

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

    DEFF Research Database (Denmark)

    Yang, Liang; Hu, Yifan; Liu, Yang

    2011-01-01

    differentiation remain largely unknown. The distinct roles of different EPS have been addressed in the present report. Both Pel and Psl polysaccharides are required for type IV pilus‐independent microcolony formation in the initial stages of biofilm formation by Pseudomonas aeruginosa PAO1. Both Pel and Psl...... polysaccharides are also essential for subpopulation interactions and macrocolony formation in the later stages of P. aeruginosa PAO1 biofilm formation. Pel and Psl polysaccharides have different impacts on Pseudomonas quinolone signal‐mediated extracellular DNA release in P. aeruginosa PAO1 biofilms. Psl...... polysaccharide is more important than Pel polysaccharide in P. aeruginosa PAO1 biofilm formation and antibiotic resistance. Our study thus suggests that different EPS materials play distinct roles during bacterial biofilm formation....

  18. An Evolving Perspective on the Pseudomonas aeruginosa Orphan Quorum Sensing Regulator QscR

    Directory of Open Access Journals (Sweden)

    Everett Peter Greenberg

    2014-10-01

    Full Text Available Many Proteobacteria govern responses to changes in cell density by using acyl-homoserine lactone (AHL quorum-sensing (QS signaling. Similar to the LuxI-LuxR system described in Vibrio fischeri, a minimal AHL QS circuit comprises a pair of genes, a luxI-type synthase gene encoding an enzyme that synthesizes an AHL and a luxR-type AHL-responsive transcription regulator gene. In most bacteria that utilize AHL QS, cognate luxI and luxR homologs are found in proximity to each other on the chromosome. However, a number of recent reports have identified luxR homologs that are not linked to luxI homologs; in some cases luxR homologs have been identified in bacteria that have no luxI homologs. A luxR homolog without a linked luxI homologs is termed an orphan or solo. One of the first reports of an orphan was on QscR in Pseudomonas aeruginosa. The qscR gene was revealed by whole genome sequencing and has been studied in some detail. P. aeruginosa encodes two AHL synthases and three AHL responsive receptors, LasI-LasR form a cognate synthase-receptor pair as do RhlI-RhlR. QscR lacks a linked synthase and responds to the LasI-generated AHL. QS regulation gene regulation in P. aeruginosa employs multiple signals and occurs in the context of other interconnected regulatory circuits that control diverse physiological functions. QscR affects virulence of P. aeruginosa, and although it shows sensitivity to the LasI-generated AHL, 3-oxo-dodecanoylhomoserine lactone, it’s specificity is relaxed compared to LasR and can respond equally well to several AHLs. QscR controls a set of genes that overlaps the set regulated by LasR. QscR is comparatively easy to purify and study in vitro, and has become a model for understanding the biochemistry of LuxR homologs. In fact there is a crystal structure of QscR bound to the LasI-generated AHL. Here, we review the current state of research concerning QscR and highlight recent advances in our understanding of its structure

  19. Strong incidence of Pseudomonas aeruginosa on bacterial rrs and ITS genetic structures of cystic fibrosis sputa.

    Science.gov (United States)

    Pages-Monteiro, Laurence; Marti, Romain; Commun, Carine; Alliot, Nolwenn; Bardel, Claire; Meugnier, Helene; Perouse-de-Montclos, Michele; Reix, Philippe; Durieu, Isabelle; Durupt, Stephane; Vandenesch, Francois; Freney, Jean; Cournoyer, Benoit; Doleans-Jordheim, Anne

    2017-01-01

    Cystic fibrosis (CF) lungs harbor a complex community of interacting microbes, including pathogens like Pseudomonas aeruginosa. Meta-taxogenomic analysis based on V5-V6 rrs PCR products of 52 P. aeruginosa-positive (Pp) and 52 P. aeruginosa-negative (Pn) pooled DNA extracts from CF sputa suggested positive associations between P. aeruginosa and Stenotrophomonas and Prevotella, but negative ones with Haemophilus, Neisseria and Burkholderia. Internal Transcribed Spacer analyses (RISA) from individual DNA extracts identified three significant genetic structures within the CF cohorts, and indicated an impact of P. aeruginosa. RISA clusters Ip and IIIp contained CF sputa with a P. aeruginosa prevalence above 93%, and of 24.2% in cluster IIp. Clusters Ip and IIIp showed lower RISA genetic diversity and richness than IIp. Highly similar cluster IIp RISA profiles were obtained from two patients harboring isolates of a same P. aeruginosa clone, suggesting convergent evolution in the structure of their microbiota. CF patients of cluster IIp had received significantly less antibiotics than patients of clusters Ip and IIIp but harbored the most resistant P. aeruginosa strains. Patients of cluster IIIp were older than those of Ip. The effects of P. aeruginosa on the RISA structures could not be fully dissociated from the above two confounding factors but several trends in these datasets support the conclusion of a strong incidence of P. aeruginosa on the genetic structure of CF lung microbiota.

  20. DdaR (PA1196) Regulates Expression of Dimethylarginine Dimethylaminohydrolase for the Metabolism of Methylarginines in Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Lundgren, Benjamin R; Bailey, Frank J; Moley, Gabriella; Nomura, Christopher T

    2017-04-15

    Dimethylarginine dimethylaminohydrolases (DDAHs) catalyze the hydrolysis of methylarginines to yield l-citrulline and methylamines as products. DDAHs and their central roles in methylarginine metabolism have been characterized for eukaryotic cells. While DDAHs are known to exist in some bacteria, including Streptomyces coelicolor and Pseudomonas aeruginosa, the physiological importance and genetic regulation of bacterial DDAHs remain poorly understood. To provide some insight into bacterial methylarginine metabolism, this study focused on identifying the key elements or factors regulating DDAH expression in P. aeruginosa PAO1. First, results revealed that P. aeruginosa can utilize NG ,NG -dimethyl-l-arginine (ADMA) as a sole source of nitrogen but not carbon. Second, expression of the ddaH gene was observed to be induced in the presence of methylarginines, including NG -monomethyl-l-arginine (l-NMMA) and ADMA. Third, induction of the ddaH gene was shown to be achieved through a mechanism consisting of the putative enhancer-binding protein PA1196 and the alternative sigma factor RpoN. Both PA1196 and RpoN were essential for the expression of the ddaH gene in response to methylarginines. On the basis of the results of this study, PA1196 was given the name DdaR, for dimethylarginine dimethylaminohydrolase regulator. Interestingly, DdaR and its target ddaH gene are conserved only among P. aeruginosa strains, suggesting that this particular Pseudomonas species has evolved to utilize methylarginines from its environment.IMPORTANCE Methylated arginine residues are common constituents of eukaryotic proteins. During proteolysis, methylarginines are released in their free forms and become accessible nutrients for bacteria to utilize as growth substrates. In order to have a clearer and better understanding of this process, we explored methylarginine utilization in the metabolically versatile bacterium Pseudomonas aeruginosa PAO1. Our results show that the transcriptional

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

    OpenAIRE

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

    2016-01-01

    The increased reliance on colistin for treating multidrug-resistant Gram-negative bacterial infections has resulted in the emergence of colistin-resistant Pseudomonas aeruginosa. We attempted to identify genetic contributors to colistin resistance in vitro evolved isogenic colistin-resistant and -susceptible strains of two P. aeruginosa lineages (P5 and P155). Their evolutionary paths to acquisition and loss of colistin resistance were also tracked. Comparative genomic analysis revealed 13 an...

  2. Evaluation of antibiotic effects on Pseudomonas aeruginosa biofilm using Raman spectroscopy and multivariate analysis

    OpenAIRE

    Jung, Gyeong Bok; Nam, Seong Won; Choi, Samjin; Lee, Gi-Ja; Park, Hun-Kuk

    2014-01-01

    We investigate the mode of action and classification of antibiotic agents (ceftazidime, patulin, and epigallocatechin gallate; EGCG) on Pseudomonas aeruginosa (P. aeruginosa) biofilm using Raman spectroscopy with multivariate analysis, including support vector machine (SVM) and principal component analysis (PCA). This method allows for quantitative, label-free, non-invasive and rapid monitoring of biochemical changes in complex biofilm matrices with high sensitivity and specificity. In this s...

  3. Genetic diversity of clinical Pseudomonas aeruginosa isolates in a public hospital in Spain

    OpenAIRE

    Gomila, Margarita; del Carmen Gallegos, Maria; Fernández-Baca, Victoria; Pareja, Antonio; Pascual, Margalida; Díaz-Antolín, Paz; García-Valdés, Elena; Lalucat, Jorge

    2013-01-01

    Abstract Background Pseudomonas aeruginosa is an important nosocomial pathogen that exhibits multiple resistances to antibiotics with increasing frequency, making patient treatment more difficult. The aim of the study is to ascertain the population structure of this clinical pathogen in the Hospital Son Llàtzer, Spain. Results A significant set (56) of randomly selected clinical P. aeruginosa isolates, including multidrug and non-multidrug resistant isolates, were assigned to sequence types (...

  4. Identification of Genes Involved in Pseudomonas aeruginosa Biofilm-Specific Resistance to Antibiotics

    OpenAIRE

    Zhang, Li; Fritsch, Meredith; Hammond, Lisa; Landreville, Ryan; Slatculescu, Cristina; Colavita, Antonio; Mah, Thien-Fah

    2013-01-01

    Pseudomonas aeruginosa is a key opportunistic pathogen characterized by its biofilm formation ability and high-level multiple antibiotic resistance. By screening a library of random transposon insertion mutants with an increased biofilm-specifc antibiotic susceptibility, we previously identified 3 genes or operons of P. aeruginosa UCBPP-PA14 (ndvB, PA1875-1877 and tssC1) that do not affect biofilm formation but are involved in biofilm-specific antibiotic resistance. In this study, we demonstr...

  5. Outbreak of infection in a burns unit due to Pseudomonas aeruginosa originating from contaminated tubing used for irrigation of patients

    DEFF Research Database (Denmark)

    Kolmos, H J; Thuesen, B; Nielsen, S V

    1993-01-01

    Five patients with extensive deep burns developed septicaemia due to Pseudomonas aeruginosa serogroup O-7.8 and phage type 21 or 21/188 shortly after they had been admitted to hospital. Four other burned patients became colonized with the same strain. The source of infection was contaminated tap...... water used for irrigation of the burns, as part of the first-aid treatment which the patients received when entering the hospital. Contamination was restricted to showers and tubing that were permanently connected to the taps, and the outbreak stopped after they had been disinfected. Tubing and showers...... bacteria. Routine typing of P. aeruginosa isolates from burned patients is indicated in order to detect and eliminate hidden sources of infection....

  6. Microbial-Influenced Corrosion of Corten Steel Compared with Carbon Steel and Stainless Steel in Oily Wastewater by Pseudomonas aeruginosa

    Science.gov (United States)

    Mansouri, Hamidreza; Alavi, Seyed Abolhasan; Fotovat, Meysam

    2015-07-01

    The microbial corrosion behavior of three important steels (carbon steel, stainless steel, and Corten steel) was investigated in semi petroleum medium. This work was done in modified nutrient broth (2 g nutrient broth in 1 L oily wastewater) in the presence of Pseudomonas aeruginosa and mixed culture (as a biotic media) and an abiotic medium for 2 weeks. The behavior of corrosion was analyzed by spectrophotometric and electrochemical methods and at the end was confirmed by scanning electron microscopy. The results show that the degree of corrosion of Corten steel in mixed culture, unlike carbon steel and stainless steel, is less than P. aeruginosa inoculated medium because some bacteria affect Corten steel less than other steels. According to the experiments, carbon steel had less resistance than Corten steel and stainless steel. Furthermore, biofilm inhibits separated particles of those steels to spread to the medium; in other words, particles get trapped between biofilm and steel.

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

    Directory of Open Access Journals (Sweden)

    Davide Vecchietti

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

  8. Successful use of intravitreal and systemic colistin in treating multidrug resistant Pseudomonas aeruginosa post-operative endophthalmitis

    Directory of Open Access Journals (Sweden)

    Preetam Samant

    2014-01-01

    Full Text Available We report a case series of post-operative endophthalmitis due to Pseudomonas aeruginosa. A total of 8 patients operated for cataract, were referred to our facility with acute onset of decreased vision 1-2 days following surgery. All patients had clinical evidence of acute exogenous endophthalmitis with severe anterior chamber exudative reaction. Ocular samples (aqueous aspirate and vitreous tap for microbiology were taken from all eyes. Microbiology from all revealed P. aeruginosa which was resistant to all antibiotics except colistin. With prompt and accurate microbiological support it was possible to control the infection in all the eyes with the use of colistin intravitreally and intravenously which to the best of our knowledge, has been never reported. Intravitreal injection of colistin could be an option effective in the management of multi-drug-resistant endophthalmitis caused by Gram-negative bacteria.

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

    Directory of Open Access Journals (Sweden)

    Guillaume Golovkine

    2016-01-01

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

  10. Potent Antibacterial Antisense Peptide-Peptide Nucleic Acid Conjugates Against Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Ghosal, Anubrata; Nielsen, Peter E

    2012-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen causing severe infections in hospital settings, especially with immune compromised patients, and the increasing prevalence of multidrug resistant strains urges search for new drugs with novel mechanisms of action. In this study we introduce...... antisense peptide-peptide nucleic acid (PNA) conjugates as antibacterial agents against P. aeruginosa. We have designed and optimized antisense peptide-PNA conjugates targeting the translation initiation region of the ftsZ gene (an essential bacterial gene involved in cell division) or the acpP gene (an...... significantly reduced bacterial survival. These results open the possibility of development of antisense antibacterials for treatment of Pseudomonas infections....

  11. Clinical utilization of genomics data produced by the international Pseudomonas aeruginosa consortium

    DEFF Research Database (Denmark)

    Freschi, Luca; Jeukens, Julie; Kukavica-Ibrulj, Irena

    2015-01-01

    major groups that are further divided into subgroups, some not previously reported in the literature. We also provide the first snapshot of P. aeruginosa strain diversity with respect to antibiotic resistance. Our approach will allow us to draw potential links between environmental strains and those......The International Pseudomonas aeruginosa Consortium is sequencing over 1000 genomes and building an analysis pipeline for the study of Pseudomonas genome evolution, antibiotic resistance and virulence genes. Metadata, including genomic and phenotypic data for each isolate of the collection...

  12. ECTHYMA GANGRENOSUM AND SEPTIC SHOCK CAUSED BY PSEUDOMONAS AERUGINOSA IN A CYTOTOXIC NEUTROPENIC PATIENT

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    I. A. Kurmukov

    2017-01-01

    Full Text Available Pseudomonas aeruginosa is an extremely dangerous cause of sepsis in patients with antitumor chemotherapyassociated neutropenia. Sometimes, the source of infection may be localized lesions of the skin (e.g. folliculitis or its derivatives, which are not of particular concern in the absence of neutropenia. The appearance of Ecthyma gangrenosum in a patient with neutropenia, even in the absence of any signs or symptoms of sepsis, requires emergency care and the appointment of antibiotics with high antipseudomonal activity. We are report the case of the complications of chemotherapy with the sequential development of Ecthyma gangrenosum and Pseudomonas aeruginosa septicemia in a patient with concomitant skin infection (folliculitis.

  13. Isolation and characterization of a bacteriophage and its utilization against multi-drug resistant Pseudomonas aeruginosa-2995.

    Science.gov (United States)

    Jamal, Muhsin; Andleeb, Saadia; Jalil, Fazal; Imran, Muhammad; Nawaz, Muhammad Asif; Hussain, Tahir; Ali, Muhammad; Das, Chythanya Rajanna

    2017-12-01

    To identify, isolate, and characterize a lytic bacteriophage against the multiple-drug resistant clinical strain of Pseudomonas aeruginosa-2995 and to determine the phage efficacy against the bacterial planktonic cells and the biofilm. Wastewater was used to isolate a bacteriophage. The phage was characterized with Transmission electron microscopy (TEM). Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE) was used to identify the expressed proteins. Bacteria were cultured in both suspension and biofilm to check and compare their susceptibility to phage lytic action. The activity of the phage (determined as AZ1) was determined against P. aeruginosa-2995 in both planktonic cells and the biofilm. A bacteriophage, designated as AZ1, was isolated from waste water showing a narrow host range. AZ1 was characterized by TEM and could be identified as an isolate in the family Siphoviridae [order Caudovirals]. Seventeen structural proteins ranging from about 12 to 110kDa were found through SDS-PAGE analysis. Its genome was confirmed as dsDNA with a length of approx. 50kb. The log-phase growth of P. aeruginosa-2995 was significantly reduced after treatment with AZ1 (4.50×108 to 2.1×103CFU/ml) as compared to control. Furthermore, phage AZ1 significantly reduced 48h old biofilm biomass about 3-fold as compared to control. Pseudomonas aeruginosa is a ubiquitous free-living opportunistic human pathogen characterized by high antibiotic tolerance and tendency for biofilm formation. The phage, identified in this study, AZ1, showed promising activity in the destruction of both planktonic cells and biofilm of P. aeruginosa-2995. However, complete eradication may require a combination of phages. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Antimicrobial Resistance and Molecular Typing of Pseudomonas Aeruginosa Isolated from Surgical Wounds in Lagos, Nigeria

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    Kehinde Akinsinde

    2012-06-01

    Full Text Available The aim of the study was to determine the resistance patterns of Pseudomonas aeruginosa isolates recovered from patients with surgical wounds in hospitals and also to investigate their epidemiological relatedness using molecular typing techniques. Twenty Pseudomonas sp. isolated from surgical wounds were subjected to antibiotic susceptibility testing by disk diffusion, plasmid profile, SDS-PAGE and PCR using the parC, gyr A gene and RAPD using the 1254 primer. The isolates showed resistance to 12 different antibiotics with six being 100% resistant. Plasmids were detected in 16 (80% of the isolates. The RAPD-PCR using the primer 1254, SDS-PAGE classified the 20 Pseudomonas spp. into 5 and 6 types respectively. Pseudomona aeruginosa strains isolated from surgical wounds were generally resistant to a broad range of antibiotics and this is rather worrisome. The typing techniques classified the 20 isolates into 5 and 6 groups.

  15. Antimicrobial resistance and molecular typing of pseudomonas aeruginosa isolated from surgical wounds in Lagos, Nigeria.

    Science.gov (United States)

    Smith, Stella; Ganiyu, Olaniyi; John, Rachael; Fowora, Muinah; Akinsinde, Kehinde; Odeigah, Peter

    2012-01-01

    The aim of the study was to determine the resistance patterns of Pseudomonas aeruginosa isolates recovered from patients with surgical wounds in hospitals and also to investigate their epidemiological relatedness using molecular typing techniques. Twenty Pseudomonas sp. isolated from surgical wounds were subjected to antibiotic susceptibility testing by disk diffusion, plasmid profile, SDS-PAGE and PCR using the parC, gyr A gene and RAPD using the 1254 primer. The isolates showed resistance to 12 different antibiotics with six being 100% resistant. Plasmids were detected in 16 (80%) of the isolates. The RAPD-PCR using the primer 1254, SDS-PAGE classified the 20 Pseudomonas spp. into 5 and 6 types respectively. Pseudomona aeruginosa strains isolated from surgical wounds were generally resistant to a broad range of antibiotics and this is rather worrisome. The typing techniques classified the 20 isolates into 5 and 6 groups.

  16. Effects of environmental conditions on the morphologic change of Pseudomonas aeruginosa and its association with antibiotic resistance in burn patients

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    Mohsen Moghoofei

    2015-12-01

    Full Text Available Introduction: Pseudomonas aeruginosa is an aerobic gram-negative bacteria, which causes hospital infections. Bacteria under stress, such as lack of food, pH and osmotic pressure change and antibiotic stress transforms its morphology to coccoid form. In the bacill form due to changes in the peptidoglycan cell wall, membrane lipids and decreased metabolic activity, bacteria resistant to antibiotics. Due to an increase in mortality in burn patients and important problem of antibiotic resistance in P.aeruginosa the researcher decided to study the factors affecting on morphologic change to coccoid form. Materials and methods: In this study P.aeruginosa strains obtained from clinical samples of burned patients (8 samples were taken from the wound by Infectious Disease Specialist and standard strain ATCC 27853 were used. Samples were confirmed by biochemical tests and PCR by 16srDNA primer. Then bacteria were put under lack of food and antibiotic stress invitro. After that bacterial morphology was examined on different days by digital DP 72-BX 51 microscope to 60 days. After induction coccoid forms, bacterial viability was confirmed by flow cytometry. Results: Bacteria begin to change morphology from 5 days for antibiotic stress and 10 days for other stress. Changing morphology was initially elongate bacilli, U shape and finally the coccoid form was seen. Discussion and conclusion: Changing morphology of bacilli to coccoid bacteria that are the result of stress on the bacteria which enter the body can lead to bacterial resistance to antibiotics and have grave consequences for the patient.

  17. A shotgun antisense approach to the identification of novel essential genes in Pseudomonas aeruginosa.

    Science.gov (United States)

    Rusmini, Ruggero; Vecchietti, Davide; Macchi, Raffaella; Vidal-Aroca, Faustino; Bertoni, Giovanni

    2014-02-05

    Antibiotics in current use target a surprisingly small number of cellular functions: cell wall, DNA, RNA, and protein biosynthesis. Targeting of novel essential pathways is expected to play an important role in the discovery of new antibacterial agents against bacterial pathogens, such as Pseudomonas aeruginosa, that are difficult to control because of their ability to develop resistance, often multiple, to all current classes of clinical antibiotics. We aimed to identify novel essential genes in P. aeruginosa by shotgun antisense screening. This technique was developed in Staphylococcus aureus and, following a period of limited success in Gram-negative bacteria, has recently been used effectively in Escherichia coli. To also target low expressed essential genes, we included some variant steps that were expected to overcome the non-stringent regulation of the promoter carried by the expression vector used for the shotgun antisense libraries. Our antisense screenings identified 33 growth-impairing single-locus genomic inserts that allowed us to generate a list of 28 "essential-for-growth" genes: five were "classical" essential genes involved in DNA replication, transcription, translation, and cell division; seven were already reported as essential in other bacteria; and 16 were "novel" essential genes with no homologs reported to have an essential role in other bacterial species. Interestingly, the essential genes in our panel were suggested to take part in a broader range of cellular functions than those currently targeted by extant antibiotics, namely protein secretion, biosynthesis of cofactors, prosthetic groups and carriers, energy metabolism, central intermediary metabolism, transport of small molecules, translation, post-translational modification, non-ribosomal peptide synthesis, lipopolysaccharide synthesis/modification, and transcription regulation. This study also identified 43 growth-impairing inserts carrying multiple loci targeting 105 genes, of which

  18. Molecular analysis of volatile metabolites released specifically by staphylococcus aureus and pseudomonas aeruginosa

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    Filipiak Wojciech

    2012-06-01

    Full Text Available Abstract Background The routinely used microbiological diagnosis of ventilator associated pneumonia (VAP is time consuming and often requires invasive methods for collection of human specimens (e.g. bronchoscopy. Therefore, it is of utmost interest to develop a non-invasive method for the early detection of bacterial infection in ventilated patients, preferably allowing the identification of the specific pathogens. The present work is an attempt to identify pathogen-derived volatile biomarkers in breath that can be used for early and non- invasive diagnosis of ventilator associated pneumonia (VAP. For this purpose, in vitro experiments with bacteria most frequently found in VAP patients, i.e. Staphylococcus aureus and Pseudomonas aeruginosa, were performed to investigate the release or consumption of volatile organic compounds (VOCs. Results Headspace samples were collected and preconcentrated on multibed sorption tubes at different time points and subsequently analyzed with gas chromatography mass spectrometry (GC-MS. As many as 32 and 37 volatile metabolites were released by S. aureus and P. aeruginosa, respectively. Distinct differences in the bacteria-specific VOC profiles were found, especially with regard to aldehydes (e.g. acetaldehyde, 3-methylbutanal, which were taken up only by P. aeruginosa but released by S. aureus. Differences in concentration profiles were also found for acids (e.g. isovaleric acid, ketones (e.g. acetoin, 2-nonanone, hydrocarbons (e.g. 2-butene, 1,10-undecadiene, alcohols (e.g. 2-methyl-1-propanol, 2-butanol, esters (e.g. ethyl formate, methyl 2-methylbutyrate, volatile sulfur compounds (VSCs, e.g. dimethylsulfide and volatile nitrogen compounds (VNCs, e.g. 3-methylpyrrole. Importantly, a significant VOC release was found already 1.5 hours after culture start, corresponding to cell numbers of ~8*106 [CFUs/ml]. Conclusions The results obtained provide strong evidence that the detection and perhaps even

  19. Post-transcriptional regulation of gene PA5507 controls PQS concentration in Pseudomonas aeruginosa

    OpenAIRE

    Tipton, Kyle A.; Coleman, James P.; Pesci, Everett C.

    2015-01-01

    Pseudomonas aeruginosa can sense and respond to a myriad of environmental signals and utilizes a system of small molecules to communicate through intercellular signaling. The small molecule 2-heptyl-3-hydroxy-4-quinolone (Pseudomonas Quinolone Signal [PQS]) is one of these signals and its synthesis is important for virulence. Previously, we identified an RpiR-type transcriptional regulator, QapR, that positively affects PQS production by repressing the qapR operon. An in-frame deletion of thi...

  20. Two isoforms of Clp peptidase in Pseudomonas aeruginosa control distinct aspects of cellular physiology.

    Science.gov (United States)

    Hall, Branwen M; Breidenstein, Elena B M; de la Fuente-Núñez, César; Reffuveille, Fany; Mawla, Gina D; Hancock, Robert E W; Baker, Tania A

    2016-11-14

    Caseinolytic peptidases (ClpPs) regulate diverse aspects of cellular physiology in bacteria. Some species have multiple ClpPs including opportunistic pathogen Pseudomonas aeruginosa in which there is an archetypical isoform, ClpP1, and a second isoform, ClpP2, about which little is known. Here we use phenotypic assays to investigate biological roles of ClpP1 and ClpP2 and biochemical assays to characterize purified ClpP1, ClpP2, ClpX and ClpA. Interestingly ClpP1 and ClpP2 have distinct intracellular roles for motility, pigment production, iron scavenging and biofilm formation. Of particular interest ClpP2, but not ClpP1, is required for microcolony organization, where multicellular, organized structures first form on the pathway to biofilm production. We found that purified ClpP1, with ClpX or ClpA was enzymatically active, yet to our surprise ClpP2 was inactive and not fully assembled in vitro; attempts to assist ClpP2 assembly and activation by mixing with the other Clp components failed to turn on ClpP2, as did solution conditions that have helped activate other ClpPs in vitro We postulate that the active form of ClpP2 has yet to be discovered and present several potential models to explain its activation as well as the unique role ClpP2 plays in development of the clinically important biofilms in P. aeruginosa IMPORTANCE: Pseudomonas aeruginosa is responsible for severe infections of immunocompromised patients. Our work demonstrates that two different isoforms of Clp peptidase, ClpP1 and ClpP2, control distinct aspects of cellular physiology for this organism. In particular, we identify ClpP2 as necessary for microcolony organization. Pure, active forms of ClpP1 and either ClpX, or ClpA were characterized as assembled and active, ClpP2 was incompletely assembled and inactive. By establishing both the unique biological roles of ClpP1 and ClpP2 and their initial biochemical assemblies, we set the stage for important future work on the structure, function and