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Sample records for aeruginosa forms biofilms

  1. Pseudomonas aeruginosa forms Biofilms in Acute InfectionIndependent of Cell-to-Cell Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Schaber, J. Andy; Triffo, W.J.; Suh, Sang J.; Oliver, Jeffrey W.; Hastert, Mary C.; Griswold, John A.; Auer, Manfred; Hamood, Abdul N.; Rumbaugh, Kendra P.

    2006-09-20

    Biofilms are bacterial communities residing within a polysaccharide matrix that are associated with persistence and antibiotic resistance in chronic infections. We show that the opportunistic pathogen Pseudomonas aeruginosa forms biofilms within 8 hours of infection in thermally-injured mice, demonstrating that biofilms contribute to bacterial colonization in acute infections. P. aeruginosa biofilms were visualized within burned tissue surrounding blood vessels and adipose cells. Although quorum sensing (QS), a bacterial signaling mechanism, coordinates differentiation of biofilms in vitro, wild type and QS-deficient P. aeruginosa formed similar biofilms in vivo. Our findings demonstrate that P. aeruginosa forms biofilms on specific host tissues independent of QS.

  2. Polysaccharides serve as scaffold of biofilms formed by mucoid Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Yang, Liang; Hengzhuang, Wang; Wu, Hong;

    2012-01-01

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

    OpenAIRE

    Schaber, J. Andy; Triffo, W.J.; Suh, Sang J.; Oliver, Jeffrey W.; Hastert, Mary C.; Griswold, John A.; Auer, Manfred; Hamood, Abdul N; Rumbaugh, Kendra P.

    2007-01-01

    Biofilms are bacterial communities residing within a polysaccharide matrix that are associated with persistence and antibiotic resistance in chronic infections. We show that the opportunistic pathogen Pseudomonas aeruginosa forms biofilms within 8 h of infection in thermally injured mice, demonstrating that biofilms contribute to bacterial colonization in acute infections as well. Using light, electron, and confocal scanning laser microscopy, P. aeruginosa biofilms were visualized within burn...

  4. 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...

  5. Pseudomonas aeruginosa biofilm infections

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim

    2014-01-01

    use of conventional antimicrobial compounds in many cases cannot eradicate biofilms, there is an urgent need to develop alternative measures to combat biofilm infections. The present review is focussed on the important opportunistic pathogen and biofilm model organism Pseudomonas aeruginosa. Initially...

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    important for understanding of biofilm physiology and the treatment of biofilm-related infectious diseases. Here, we have investigated interactions of two of the major bacterial species of cystic fibrosis lung microbial communities -Pseudomonas aeruginosa and Staphylococcus aureus- when grown in co......-culture biofilms. By growing co-culture biofilms of S. aureus with P. aeruginosa mutants in a flow-chamber system and observing them using confocal laser scanning microscopy, we show that wild-type P. aeruginosa PAO1 facilitates S. aureus microcolony formation. In contrast, P. aeruginosa mucA and rpoN mutants do...... not facilitate S. aureus microcolony formation and tend to outcompete S. aureus in co-culture biofilms. Further investigations reveal that extracellular DNA (eDNA) plays an important role in S. aureus microcolony formation and that P. aeruginosa type IV pili are required for this process, probably through...

  7. Biofilm-forming Pseudomonas aeruginosa bacteria undergo lipopolysaccharide structural modifications and induce enhanced inflammatory cytokine response in human monocytes.

    Science.gov (United States)

    Ciornei, Cristina D; Novikov, Alexey; Beloin, Christophe; Fitting, Catherine; Caroff, Martine; Ghigo, Jean-Marc; Cavaillon, Jean-Marc; Adib-Conquy, Minou

    2010-10-01

    To determine whether growth of bacteria in biofilms triggers a specific immune response, we compared cytokine induction in human monocytes and mouse macrophages by planktonic and biofilm bacteria. We compared Pseudomonas aeruginosa and Staphylococcus aureus, two bacteria often colonizing the airways of cystic fibrosis patients. Planktonic and biofilm S. aureus induced equivalent amounts of cytokine in human monocytes. In contrast, biofilm-forming P. aeruginosa induced a higher production of tumor necrosis factor and interleukin-6 than their planktonic counterpart, both for clinical isolates and laboratory strains. This increased cytokine production was partly dependent on phagocytosis. In contrast, no difference in cytokine induction was observed with mouse macrophages. We investigated the structures of the lipopolysaccharides (LPSs) of these Gram-negative bacteria in biofilm and planktonic cultures of P. aeruginosa. Switch between the two life-styles was shown to cause several reversible LPS structure modifications affecting the lipid A and polysaccharide moieties of both clinical isolates and laboratory strains. In addition, LPS isolated from biofilm-grown bacteria induced slightly more inflammatory cytokines than that extracted from its planktonic counterpart. Our results, therefore, show that P. aeruginosa biofilm LPS undergoes structural modifications that only partially contribute to an increased inflammatory response from human monocytes. PMID:19710099

  8. Silver against Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

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

    2007-01-01

    bacteria in both the planktonic and biofilm modes of growth. The action of silver on mature in vitro biofilms of Pseudomonas aeruginosa, a primary pathogen of chronic infected wounds, was investigated. The results show that silver is very effective against mature biofilms of P. aeruginosa......, but that the silver concentration is important. A concentration of 5-10 ig/mL silver sulfadiazine eradicated the biofilm whereas a lower concentration (1 ig/mL) had no effect. The bactericidal concentration of silver required to eradicate the bacterial biofilm was 10-100 times higher than that used to eradicate...... planktonic bacteria. These observations strongly indicate that the concentration of silver in currently available wound dressings is much too low for treatment of chronic biofilm wounds. It is suggested that clinicians and manufacturers of the said wound dressings consider whether they are treating wounds...

  9. Pseudomonas aeruginosa Biofilm Infections

    DEFF Research Database (Denmark)

    Rybtke, Morten; Hultqvist, Louise Dahl; Givskov, Michael;

    2015-01-01

    Studies of biopsies from infectious sites, explanted tissue and medical devises have provided evidence that biofilms are the underlying cause of a variety of tissue-associated and implant-associated recalcitrant human infections. With a need for novel anti-biofilm treatment strategies, research...... in biofilm infection microbiology, biofilm formation mechanisms and biofilm-associated antimicrobial tolerance has become an important area in microbiology. Substantial knowledge about biofilm formation mechanisms, biofilm-associated antimicrobial tolerance and immune evasion mechanisms has been obtained...... through work with biofilms grown in in vitro experimental setups, and the relevance of this information in the context of chronic infections is being investigated by the use of animal models of infection. Because our current in vitro experimental setups and animal models have limitations, new advanced...

  10. Photodynamic antibacterial and antibiofilm activity of RLP068/Cl against Staphylococcus aureus and Pseudomonas aeruginosa forming biofilms on prosthetic material.

    Science.gov (United States)

    Vassena, Christian; Fenu, Simone; Giuliani, Francesco; Fantetti, Lia; Roncucci, Gabrio; Simonutti, Giulio; Romanò, Carlo Luca; De Francesco, Raffaele; Drago, Lorenzo

    2014-07-01

    Prosthetic joint infections (PJIs) are becoming a growing public health concern in developed countries as more people undergo arthroplasty for bone fixation or joint replacement. Because a wide range of bacterial strains responsible for PJIs can produce biofilms on prosthetic implants and because the biofilm structure confers elevated bacterial resistance to antibiotic therapy, new drugs and therapies are needed to improve the clinical outcome of treatment of PJIs. Antimicrobial photodynamic therapy (APDT), a non-antibiotic broad-spectrum antimicrobial treatment, is also active against multidrug-resistant micro-organisms such as meticillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. APDT uses a photosensitiser that targets bacterial cells following exposure to visible light. APDT with RLP068/Cl, a novel photosensitiser, was studied by confocal laser scanning microscopy (CLSM) to evaluate the disruption of MRSA and P. aeruginosa biofilms on prosthetic material. Quantitative CLSM studies showed a reduction in biofilm biomass (biofilm disruption) and a decrease in viable cell numbers, as determined by standard plate counting, in the S. aureus and P. aeruginosa biofilms exposed to APDT with the photosensitiser RLP068/Cl. APDT with RLP068/Cl may be a useful approach to the treatment of PJI-associated biofilms.

  11. Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Maria; Bjarnsholt, Thomas; Givskov, Michael;

    2014-01-01

    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...... mechanism used to coordinate expression of virulence and protection of aggregated biofilm cells. Rhamnolipids are known for their ability to cause hemolysis and have been shown to cause lysis of several cellular components of the human immune system, for example, macrophages and polymorphonuclear leukocytes...

  12. 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.

  13. The chemical digestion of Ti6Al7Nb scaffolds produced by Selective Laser Melting reduces significantly ability of Pseudomonas aeruginosa to form biofilm.

    Science.gov (United States)

    Junka, Adam F; Szymczyk, Patrycja; Secewicz, Anna; Pawlak, Andrzej; Smutnicka, Danuta; Ziółkowski, Grzegorz; Bartoszewicz, Marzenna; Chlebus, Edward

    2016-01-01

    In our previous work we reported the impact of hydrofluoric and nitric acid used for chemical polishing of Ti-6Al-7Nb scaffolds on decrease of the number of Staphylococcus aureus biofilm forming cells. Herein, we tested impact of the aforementioned substances on biofilm of Gram-negative microorganism, Pseudomonas aeruginosa, dangerous pathogen responsible for plethora of implant-related infections. The Ti-6Al-7Nb scaffolds were manufactured using Selective Laser Melting method. Scaffolds were subjected to chemical polishing using a mixture of nitric acid and fluoride or left intact (control group). Pseudomonal biofilm was allowed to form on scaffolds for 24 hours and was removed by mechanical vortex shaking. The number of pseudomonal cells was estimated by means of quantitative culture and Scanning Electron Microscopy. The presence of nitric acid and fluoride on scaffold surfaces was assessed by means of IR and rentgen spetorscopy. Quantitative data were analysed using the Mann-Whitney test (P ≤ 0.05). Our results indicate that application of chemical polishing correlates with significant drop of biofilm-forming pseudomonal cells on the manufactured Ti-6Al-7Nb scaffolds ( p = 0.0133, Mann-Whitney test) compared to the number of biofilm-forming cells on non-polished scaffolds. As X-ray photoelectron spectroscopy revealed the presence of fluoride and nitrogen on the surface of scaffold, we speculate that drop of biofilm forming cells may be caused by biofilm-supressing activity of these two elements.

  14. The chemical digestion of Ti6Al7Nb scaffolds produced by Selective Laser Melting reduces significantly ability of Pseudomonas aeruginosa to form biofilm.

    Science.gov (United States)

    Junka, Adam F; Szymczyk, Patrycja; Secewicz, Anna; Pawlak, Andrzej; Smutnicka, Danuta; Ziółkowski, Grzegorz; Bartoszewicz, Marzenna; Chlebus, Edward

    2016-01-01

    In our previous work we reported the impact of hydrofluoric and nitric acid used for chemical polishing of Ti-6Al-7Nb scaffolds on decrease of the number of Staphylococcus aureus biofilm forming cells. Herein, we tested impact of the aforementioned substances on biofilm of Gram-negative microorganism, Pseudomonas aeruginosa, dangerous pathogen responsible for plethora of implant-related infections. The Ti-6Al-7Nb scaffolds were manufactured using Selective Laser Melting method. Scaffolds were subjected to chemical polishing using a mixture of nitric acid and fluoride or left intact (control group). Pseudomonal biofilm was allowed to form on scaffolds for 24 hours and was removed by mechanical vortex shaking. The number of pseudomonal cells was estimated by means of quantitative culture and Scanning Electron Microscopy. The presence of nitric acid and fluoride on scaffold surfaces was assessed by means of IR and rentgen spetorscopy. Quantitative data were analysed using the Mann-Whitney test (P ≤ 0.05). Our results indicate that application of chemical polishing correlates with significant drop of biofilm-forming pseudomonal cells on the manufactured Ti-6Al-7Nb scaffolds ( p = 0.0133, Mann-Whitney test) compared to the number of biofilm-forming cells on non-polished scaffolds. As X-ray photoelectron spectroscopy revealed the presence of fluoride and nitrogen on the surface of scaffold, we speculate that drop of biofilm forming cells may be caused by biofilm-supressing activity of these two elements. PMID:27150429

  15. Extracellular DNA Shields against Aminoglycosides in Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

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

    2013-01-01

    Within recent years, it has been established that extracellular DNA is a key constituent of the matrix of microbial biofilms. In addition, it has recently been demonstrated that DNA binds positively charged antimicrobials such as aminoglycosides and antimicrobial peptides. In the present study, we...... provide evidence that extracellular DNA shields against aminoglycosides in Pseudomonas aeruginosa biofilms. We show that exogenously supplemented DNA integrates into P. aeruginosa biofilms and increases their tolerance toward aminoglycosides. We provide evidence that biofilms formed by a DNA release......, which are thought to be a source of extracellular DNA at sites of infections, increases the tolerance of P. aeruginosa biofilms toward aminoglycosides. Although biofilm-associated aminoglycoside tolerance recently has been linked to extracellular DNA-mediated activation of the pmr genes, we demonstrate...

  16. Novel Targets for Treatment of Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Morten; Alhede, Maria; Bjarnsholt, Thomas

    2014-01-01

    Pseudomonas aeruginosa causes infection in all parts of the human body. The bacterium is naturally resistant to a wide range of antibiotics. In addition to resistance mechanisms such as efflux pumps, the ability to form aggregates, known as biofilm, further reduces Pseudomonas aeruginosa’s suscep......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 susceptibility to antibiotics. The presence of such biofilms is acknowledged to equal a persistent infection due to their inherent high tolerance to all antimicrobials and immune cells. In this chapter we discuss the mechanisms of biofilm tolerance. The latest biofilm research is reviewed and future treatment...... strategies such as quorum sensing inhibitors, silver, and antibodies are thoroughly evaluated....

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

    OpenAIRE

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

    2009-01-01

    Virtually all cells living in multicellular structures such as tissues and organs are encased in an extracellular matrix. One of the most important features of a biofilm is the extracellular polymeric substance that functions as a matrix, holding bacterial cells together. Yet very little is known about how the matrix forms or how matrix components encase bacteria during biofilm development. Pseudomonas aeruginosa forms environmentally and clinically relevant biofilms and is a paradigm organis...

  18. 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...

  19. 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.

  20. Stratified growth in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

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

    2004-01-01

    In this study, stratified patterns of protein synthesis and growth were demonstrated in Pseudomonas aeruginosa biofilms. Spatial patterns of protein synthetic activity inside biofilms were characterized by the use of two green fluorescent protein (GFP) reporter gene constructs. One construct...... synthesis was restricted to a narrow band in the part of the biofilm adjacent to the source of oxygen. The zone of active GFP expression was approximately 60 Am wide in colony biofilms and 30 Am wide in flow cell biofilms. The region of the biofilm in which cells were capable of elongation was mapped...... by treating colony biofilms with carbenicillin, which blocks cell division, and then measuring individual cell lengths by transmission electron microscopy. Cell elongation was localized at the air interface of the biofilm. The heterogeneous anabolic patterns measured inside these biofilms were likely a result...

  1. Pseudomonas aeruginosa facilitates Campylobacter jejuni growth in biofilms under oxic flow conditions.

    Science.gov (United States)

    Culotti, Alessandro; Packman, Aaron I

    2015-12-01

    We investigated the growth of Campylobacter jejuni in biofilms with Pseudomonas aeruginosa under oxic flow conditions. We observed the growth of C. jejuni in mono-culture, deposited on pre-established P. aeruginosa biofilms, and co-inoculated with P. aeruginosa. In mono-culture, C. jejuni was unable to form biofilms. However, deposited C. jejuni continuously grew on pre-established P. aeruginosa biofilms for a period of 3 days. The growth of scattered C. jejuni clusters was strictly limited to the P. aeruginosa biofilm surface, and no intergrowth was observed. Co-culturing of C. jejuni and P. aeruginosa also enabled the growth of both organisms in biofilms, with C. jejuni clusters developing on the surface of the P. aeruginosa biofilm. Dissolved oxygen (DO) measurements in the medium showed that P. aeruginosa biofilms depleted the effluent DO from 9.0 to 0.5 mg L(-1) 24 hours after inoculation. The localized microaerophilic environment generated by P. aeruginosa promoted the persistence and growth of C. jejuni. Our findings show that P. aeruginosa not only prolongs the survival of C. jejuni under oxic conditions, but also enables the growth of C. jejuni on the surface of P. aeruginosa biofilms.

  2. Pseudomonas aeruginosa biofilms in cystic fibrosis

    DEFF Research Database (Denmark)

    Høiby, Niels; Ciofu, Oana; Bjarnsholt, Thomas

    2010-01-01

    The persistence of chronic Pseudomonas aeruginosa lung infections in cystic fibrosis (CF) patients is due to biofilm-growing mucoid (alginate-producing) strains. A biofilm is a structured consortium of bacteria, embedded in a self-produced polymer matrix consisting of polysaccharide, protein...

  3. Glycopeptide dendrimers as Pseudomonas aeruginosa biofilm inhibitors.

    Science.gov (United States)

    Reymond, Jean-Louis; Bergmann, Myriam; Darbre, Tamis

    2013-06-01

    Synthetic glycopeptide dendrimers composed of a branched oligopeptide tree structure appended with glycosidic groups at its multiple N-termini were investigated for binding to the Pseudomonas aeruginosa lectins LecB and LecA. These lectins are partly responsible for the formation of antibiotic resistant biofilms in the human pathogenic bacterium P. aeruginosa, which causes lethal airway infections in immune-compromised and cystic fibrosis patients. Glycopeptide dendrimers with high affinity to the lectins were identified by screening of combinatorial libraries. Several of these dendrimers, in particular the LecB specific glycopeptide dendrimers FD2 and D-FD2 and the LecA specific glycopeptide dendrimers GalAG2 and GalBG2, also efficiently block P. aeruginosa biofilm formation and induce biofilm dispersal in vitro. Structure-activity relationship and structural studies are reviewed, in particular the observation that multivalency is essential to the anti-biofilm effect in these dendrimers.

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  5. Identification of peptides derived from the human antimicrobial peptide LL-37 active against biofilms formed by Pseudomonas aeruginosa using a library of truncated fragments

    NARCIS (Netherlands)

    C. Nagant; B. Pitts; K. Nazmi; M. Vandenbranden; J.G. Bolscher; P.S. Stewart; J-P. Dehaye

    2012-01-01

    Persistent Pseudomonas aeruginosa infections are a major cause of morbidity and mortality in cystic fibrosis (CF) patients and are linked to the formation of a biofilm. The development of new biofilm inhibition strategies is thus a major challenge. LL-37 is the only human antimicrobial peptide deriv

  6. Targeting quorum sensing in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

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

    2013-01-01

    Bacterial resistance to conventional antibiotics combined with an increasing acknowledgement of the role of biofilms in chronic infections has led to a growing interest in new antimicrobial strategies that target the biofilm mode of growth. In the aggregated biofilm mode, cell-to-cell communication...... alternative antibacterial strategies. Here, we review state of the art research of quorum sensing inhibitors against the opportunistic human pathogen Pseudomonas aeruginosa, which is found in a number of biofilm-associated infections and identified as the predominant organism infecting the lungs of cystic...

  7. 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...

  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. Ginger extract inhibits biofilm formation by Pseudomonas aeruginosa PA14.

    Directory of Open Access Journals (Sweden)

    Han-Shin Kim

    Full Text Available 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.

  10. 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.

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

    DEFF Research Database (Denmark)

    Pamp, Sünje Johanna; Tolker-Nielsen, Tim

    2007-01-01

    Recent studies have indicated that biosurfactants produced by Pseudomonas aeruginosa play a role both in maintaining channels between multicellular structures in biofilms and in dispersal of cells from biofilms. Through the use of flow cell technology and enhanced confocal laser scanning microscopy......, we have obtained results which suggest that the biosurfactants produced by P. aeruginosa play additional roles in structural biofilm development. We present genetic evidence that during biofilm development by P. aeruginosa, biosurfactants promote microcolony formation in the initial phase....... aeruginosa rhl4 mutants were defective in migration-dependent development of mushroom-shaped multicellular structures in the later phase of biofilm formation. Experiments involving three-color-coded mixed-strain P. aeruginosa biofilms demonstrated that the wild-type and rhl4 and pil4 mutant strains formed...

  12. Alginate production affects Pseudomonas aeruginosa biofilm development and architecture, but is not essential for biofilm formation

    DEFF Research Database (Denmark)

    Stapper, A.P.; Narasimhan, G.; Oman, D.E.;

    2004-01-01

    Extracellular polymers can facilitate the non-specific attachment of bacteria to surfaces and hold together developing biofilms. This study was undertaken to qualitatively and quantitatively compare the architecture of biofilms produced by Pseudomonas aeruginosa strain PAO1 and its alginate......-overproducing (mucA22) and alginate-defective (algD) variants in order to discern the role of alginate in biofilm formation. These strains, PAO1, Alg(+) PAOmucA22 and Alg(-) PAOalgD, tagged with green fluorescent protein, were grown in a continuous flow cell system to characterize the developmental cycles...... of their biofilm formation using confocal laser scanning microscopy. Biofilm Image Processing (BIP) and Community Statistics (COMSTAT) software programs were used to provide quantitative measurements of the two-dimensional biofilm images. All three strains formed distinguishable biofilm architectures, indicating...

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

    OpenAIRE

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

    2016-01-01

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

  14. Functionalized polyanilines disrupt Pseudomonas aeruginosa and Staphylococcus aureus biofilms.

    Science.gov (United States)

    Gizdavic-Nikolaidis, Marija R; Pagnon, Joanne C; Ali, Naseem; Sum, Reuben; Davies, Noel; Roddam, Louise F; Ambrose, Mark

    2015-12-01

    The purpose of the present study was to investigate the antimicrobial effects of functionalized polyanilines (fPANIs) against stationary phase cells and biofilms of Pseudomonas aeruginosa and Staphylococcus aureus using homopolymer of sulfanilic acid (poly-SO3H) as a model. The chemically synthesized poly-SO3H was characterized using Fourier Transform Infra-Red (FTIR) and Ultraviolet-Visible (UV-Vis) spectroscopies. The molecular weight (Mw) and elemental analysis of homopolymer poly-SO3H were also examined. We found that poly-SO3H was bactericidal against stationary phase cells of P. aeruginosa and S. aureus at a concentration of 20 mgml(-1). Surprisingly, we discovered that the same concentration (20 mgml(-1)) of poly-SO3H significantly disrupted and killed bacterial cells present in pre-established forty-eight hour static biofilms of these organisms, as shown by crystal violet and bacterial live/dead fluorescence staining assays. In support of these data, poly-SO3H extensively diminished the expression of bacterial genes related to biofilm formation in stationary phase cells of P. aeruginosa, and seemed to greatly reduce the amount of the quorum sensing molecule N-(3-oxododecanoyl)-l-homoserine lactone (3OC12-HSL) able to be recovered from biofilms of this organism. Furthermore, we found that poly-SO3H was able to effectively penetrate and kill cells in biofilms formed by the P. aeruginosa (AESIII) isolate derived from the sputum of a cystic fibrosis patient. Taken together, the results of the present study emphasise the broad antimicrobial activities of fPANI, and suggest that they could be developed further and used in some novel ways to construct medical devices and/or industrial equipment that are refractory to colonization by biofilm-forming bacteria.

  15. Functionalized polyanilines disrupt Pseudomonas aeruginosa and Staphylococcus aureus biofilms.

    Science.gov (United States)

    Gizdavic-Nikolaidis, Marija R; Pagnon, Joanne C; Ali, Naseem; Sum, Reuben; Davies, Noel; Roddam, Louise F; Ambrose, Mark

    2015-12-01

    The purpose of the present study was to investigate the antimicrobial effects of functionalized polyanilines (fPANIs) against stationary phase cells and biofilms of Pseudomonas aeruginosa and Staphylococcus aureus using homopolymer of sulfanilic acid (poly-SO3H) as a model. The chemically synthesized poly-SO3H was characterized using Fourier Transform Infra-Red (FTIR) and Ultraviolet-Visible (UV-Vis) spectroscopies. The molecular weight (Mw) and elemental analysis of homopolymer poly-SO3H were also examined. We found that poly-SO3H was bactericidal against stationary phase cells of P. aeruginosa and S. aureus at a concentration of 20 mgml(-1). Surprisingly, we discovered that the same concentration (20 mgml(-1)) of poly-SO3H significantly disrupted and killed bacterial cells present in pre-established forty-eight hour static biofilms of these organisms, as shown by crystal violet and bacterial live/dead fluorescence staining assays. In support of these data, poly-SO3H extensively diminished the expression of bacterial genes related to biofilm formation in stationary phase cells of P. aeruginosa, and seemed to greatly reduce the amount of the quorum sensing molecule N-(3-oxododecanoyl)-l-homoserine lactone (3OC12-HSL) able to be recovered from biofilms of this organism. Furthermore, we found that poly-SO3H was able to effectively penetrate and kill cells in biofilms formed by the P. aeruginosa (AESIII) isolate derived from the sputum of a cystic fibrosis patient. Taken together, the results of the present study emphasise the broad antimicrobial activities of fPANI, and suggest that they could be developed further and used in some novel ways to construct medical devices and/or industrial equipment that are refractory to colonization by biofilm-forming bacteria. PMID:26496473

  16. Involvement of bacterial migration in the development of complex multicellular structures in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Klausen, Mikkel; Aaes-Jorgensen, A.; Molin, Søren;

    2003-01-01

    Detailed knowledge of the developmental process from single cells scattered on a surface to complex multicellular biofilm structures is essential in order to create strategies to control biofilm development. In order to study bacterial migration patterns during Pseudomonas aeruginosa biofilm...... development, we have performed an investigation with time-lapse confocal laser scanning microscopy of biofilms formed by various combinations of colour-coded P. aeruginosa wild type and motility mutants. We show that mushroom-shaped multicellular structures in P. aeruginosa biofilms can form in a sequential...... process involving a non-motile bacterial subpopulation and a migrating bacterial subpopulation. The non-motile bacteria form the mushroom stalks by growth in certain foci of the biofilm. The migrating bacteria form the mushroom caps by climbing the stalks and aggregating on the tops in a process which...

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

    Science.gov (United States)

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

    2016-04-01

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

  18. 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 the production of an extracellular matrix that serves as a structural 'scaffolding' for the biofilm cells. Pattern formation in biofilms allows cells to position themselves favorably within nutrient gradients and enables buildup and maintenance of physiologically distinct subpopulations, which facilitates...... survival of one or more subpopulations upon environmental insult, and therefore plays an important role in the innate tolerance displayed by biofilms toward adverse conditions....

  19. Impact of Pseudomonas aeruginosa quorum sensing on biofilm persistence in an in vivo intraperitoneal foreign-body infection model

    DEFF Research Database (Denmark)

    Christensen, Louise Dahl; Moser, Claus; Jensen, Peter Ø;

    2007-01-01

    Pseudomonas aeruginosa is an opportunistic human pathogen that causes chronic biofilm-based infections in host organisms. P. aeruginosa employs quorum sensing (QS) to control expression of its virulence, and to establish and maintain chronic infections. Under such conditions, the biofilm mode...... that the efficiency of the mouse innate defence against biofilm-forming P. aeruginosa is improved when the bacteria are treated with QS drugs that induce QS deficiency....

  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. In vitro prevention of Pseudomonas aeruginosa early biofilm formation with antibiotics used in cystic fibrosis patients.

    Science.gov (United States)

    Fernández-Olmos, Ana; García-Castillo, María; Maiz, Luis; Lamas, Adelaida; Baquero, Fernando; Cantón, Rafael

    2012-08-01

    The ability of antibiotics used in bronchopulmonary infections in cystic fibrosis (CF) patients to prevent Pseudomonas aeruginosa early biofilm formation was studied using a biofilm microtitre assay with 57 non-mucoid P. aeruginosa isolates (44 first colonisers and 13 recovered during the initial intermittent colonisation stage) obtained from 35 CF patients. Minimum biofilm inhibitory concentrations (BICs) of levofloxacin, ciprofloxacin, imipenem, ceftazidime, tobramycin, colistin and azithromycin were determined by placing a peg lid with a formed biofilm onto microplates containing antibiotics. A modification of this protocol consisting of antibiotic challenge during biofilm formation was implemented in order to determine the biofilm prevention concentration (BPC), i.e. the minimum concentration able to prevent biofilm formation. The lowest BPCs were for fluoroquinolones, tobramycin and colistin and the highest for ceftazidime and imipenem. The former antibiotics had BPCs identical to or only slightly higher than their minimum inhibitory concentrations (MICs) determined by standard Clinical and Laboratory Standards Institute (CLSI) microdilution and were also active on formed biofilms as reflected by their low BIC values. In contrast, ceftazidime and imipenem were less effective for prevention of biofilm formation and on formed biofilms. In conclusion, the new BPC parameter determined in non-mucoid P. aeruginosa isolates recovered during early colonisation stages in CF patients supports early aggressive antimicrobial treatment guidelines in first P. aeruginosa-colonised CF patients. PMID:22727530

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

    OpenAIRE

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

    2008-01-01

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

  3. Drosophila melanogaster as an animal model for the study of Pseudomonas aeruginosa biofilm infections in vivo.

    Directory of Open Access Journals (Sweden)

    Heidi Mulcahy

    2011-10-01

    Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen capable of causing both acute and chronic infections in susceptible hosts. Chronic P. aeruginosa infections are thought to be caused by bacterial biofilms. Biofilms are highly structured, multicellular, microbial communities encased in an extracellular matrix that enable long-term survival in the host. The aim of this research was to develop an animal model that would allow an in vivo study of P. aeruginosa biofilm infections in a Drosophila melanogaster host. At 24 h post oral infection of Drosophila, P. aeruginosa biofilms localized to and were visualized in dissected Drosophila crops. These biofilms had a characteristic aggregate structure and an extracellular matrix composed of DNA and exopolysaccharide. P. aeruginosa cells recovered from in vivo grown biofilms had increased antibiotic resistance relative to planktonically grown cells. In vivo, biofilm formation was dependent on expression of the pel exopolysaccharide genes, as a pelB::lux mutant failed to form biofilms. The pelB::lux mutant was significantly more virulent than PAO1, while a hyperbiofilm strain (PAZHI3 demonstrated significantly less virulence than PAO1, as indicated by survival of infected flies at day 14 postinfection. Biofilm formation, by strains PAO1 and PAZHI3, in the crop was associated with induction of diptericin, cecropin A1 and drosomycin antimicrobial peptide gene expression 24 h postinfection. In contrast, infection with the non-biofilm forming strain pelB::lux resulted in decreased AMP gene expression in the fly. In summary, these results provide novel insights into host-pathogen interactions during P. aeruginosa oral infection of Drosophila and highlight the use of Drosophila as an infection model that permits the study of P. aeruginosa biofilms in vivo.

  4. Anthranilate deteriorates the structure of Pseudomonas aeruginosa biofilms and antagonizes the biofilm-enhancing indole effect.

    Science.gov (United States)

    Kim, Soo-Kyoung; Park, Ha-Young; Lee, Joon-Hee

    2015-04-01

    Anthranilate and indole are alternative degradation products of tryptophan, depending on the bacterial species. While indole enhances the biofilm formation of Pseudomonas aeruginosa, we found that anthranilate, the tryptophan degradation product of P. aeruginosa, had an opposite effect on P. aeruginosa biofilm formation, in which anthranilate deteriorated the mushroom structure of biofilm. The anthranilate effect on biofilm formation was differentially exerted depending on the developmental stage and the presence of shear force. Anthranilate slightly accelerated the initial attachment of P. aeruginosa at the early stage of biofilm development and appeared to build more biofilm without shear force. But anthranilate weakened the biofilm structure in the late stage, deteriorating the mushroom structure of biofilms with shear force to make a flat biofilm. To investigate the interplay of anthranilate with indole in biofilm formation, biofilms were cotreated with anthranilate and indole, and the results showed that anthranilate antagonized the biofilm-enhancing effect of indole. Anthranilate was able to deteriorate the preformed biofilm. The effect of anthranilate and indole on biofilm formation was quorum sensing independent. AntR, a regulator of anthranilate-degrading metabolism was synergistically activated by cotreatment with anthranilate and indole, suggesting that indole might enhance biofilm formation by facilitating the degradation of anthranilate. Anthranilate slightly but significantly affected the cyclic diguaniylate (c-di-GMP) level and transcription of major extracellular polysaccharide (Psl, Pel, and alginate) operons. These results suggest that anthranilate may be a promising antibiofilm agent and antagonize the effect of indole on P. aeruginosa biofilm formation.

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

    DEFF Research Database (Denmark)

    Tran, Cindy S; Rangel, Stephanie M; Almblad, Henrik;

    2014-01-01

    Clinical infections by Pseudomonas aeruginosa, a deadly Gram-negative, opportunistic pathogen of immunocompromised hosts, often involve the formation of antibiotic-resistant biofilms. Although biofilm formation has been extensively studied in vitro on glass or plastic surfaces, much less is known...... about biofilm formation at the epithelial barrier. We have previously shown that when added to the apical surface of polarized epithelial cells, P. aeruginosa rapidly forms cell-associated aggregates within 60 minutes of infection. By confocal microscopy we now show that cell-associated aggregates...... a previously unappreciated function for the type III translocon in the formation of P. aeruginosa biofilms at the epithelial barrier and demonstrate that biofilms may form at early time points of infection....

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

    DEFF Research Database (Denmark)

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

    1991-01-01

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

  7. Antipseudomonal agents exhibit differential pharmacodynamic interactions with human polymorphonuclear leukocytes against established biofilms of Pseudomonas aeruginosa.

    Science.gov (United States)

    Chatzimoschou, Athanasios; Simitsopoulou, Maria; Antachopoulos, Charalampos; Walsh, Thomas J; Roilides, Emmanuel

    2015-04-01

    Pseudomonas aeruginosa is the most common pathogen infecting the lower respiratory tract of cystic fibrosis (CF) patients, where it forms tracheobronchial biofilms. Pseudomonas biofilms are refractory to antibacterials and to phagocytic cells with innate immunity, leading to refractory infection. Little is known about the interaction between antipseudomonal agents and phagocytic cells in eradication of P. aeruginosa biofilms. Herein, we investigated the capacity of three antipseudomonal agents, amikacin (AMK), ceftazidime (CAZ), and ciprofloxacin (CIP), to interact with human polymorphonuclear leukocytes (PMNs) against biofilms and planktonic cells of P. aeruginosa isolates recovered from sputa of CF patients. Three of the isolates were resistant and three were susceptible to each of these antibiotics. The concentrations studied (2, 8, and 32 mg/liter) were subinhibitory for biofilms of resistant isolates, whereas for biofilms of susceptible isolates, they ranged between sub-MIC and 2 × MIC values. The activity of each antibiotic alone or in combination with human PMNs against 48-h mature biofilms or planktonic cells was determined by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] assay. All combinations of AMK with PMNs resulted in synergistic or additive effects against planktonic cells and biofilms of P. aeruginosa isolates compared to each component alone. More than 75% of CAZ combinations exhibited additive interactions against biofilms of P. aeruginosa isolates, whereas CIP had mostly antagonistic interaction or no interaction with PMNs against biofilms of P. aeruginosa. Our findings demonstrate a greater positive interaction between AMK with PMNs than that observed for CAZ and especially CIP against isolates of P. aeruginosa from the respiratory tract of CF patients.

  8. Biofilms

    OpenAIRE

    López, Daniel; Vlamakis, Hera; Kolter, Roberto

    2010-01-01

    The ability to form biofilms is a universal attribute of bacteria. Biofilms are multicellular communities held together by a self-produced extracellular matrix. The mechanisms that different bacteria employ to form biofilms vary, frequently depending on environmental conditions and specific strain attributes. In this review, we emphasize four well-studied model systems to give an overview of how several organisms form biofilms: Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and ...

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

    Science.gov (United States)

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

    2015-10-01

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

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

    DEFF Research Database (Denmark)

    Wu, Hong; Lee, Baoleri; Yang, Liang;

    2011-01-01

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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. PMID:27146505

  13. Effects of norspermidine on Pseudomonas aeruginosa biofilm formation and eradication.

    Science.gov (United States)

    Qu, Lin; She, Pengfei; Wang, Yangxia; Liu, Fengxia; Zhang, Di; Chen, Lihua; Luo, Zhen; Xu, Huan; Qi, Yong; Wu, Yong

    2016-06-01

    Biofilms are defined as aggregation of single cell microorganisms and associated with over 80% of all the microbial infections. Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen capable of leading to various infections in immunocompromised people. Recent studies showed that norspermidine, a kind of polyamine, prevented and disrupted biofilm formation by some Gram-negative bacterium. In this study, the effects of norspermidine on P. aeruginosa biofilm formation and eradication were tested. Microtiter plate combined with crystal violet staining was used to study the effects of norspermidine on P. aeruginosa initial attachment, then we employed SEM (scanning electron microscope), qRT-PCR, and QS-related virulence factor assays to investigate how norspermidine prevent biofilm formation by P. aeruginosa. We reported that high-dose norspermidine had bactericide effect on P. aeruginosa, and norspermidine began to inhibit biofilm formation and eradicate 24-h mature biofilm at concentration of 0.1 and 1 mmol/L, respectively, probably by preventing cell-surface attachment, inhibiting swimming motility, and downregulating QS-related genes expression. To investigate the potential utility of norspermidine in preventing device-related infections, we found that catheters immersed with norspermidine were effective in eradicating mature biofilm. These results suggest that norspermidine could be a potent antibiofilm agent for formulating strategies against P. aeruginosa biofilm. PMID:26817804

  14. [Research advances on regulation of Pseudomonas aeruginosa biofilm formation and its therapeutic strategies].

    Science.gov (United States)

    Wang, Wen-min; Xu, Zhi-hao

    2010-01-01

    Pseudomonas aeruginosa is an important pathogenic bacterium of nosocomial infections. The microbe easily produce biofilm which brings us much difficulties in clinical treatment. The formation processes of biofilm, including the stages of early bacteria planting, mushroom-like structure forming and extracellular matrix producing, are regulated by a series of molecules and genes. And quorum sensing system of the microbe is responsible for regulation of the whole process of biofilm formation. According to the process of biofilm formation and the mimitat associated regulation mechanism, several anti-biofilm therapeutic strategies have been applied in clinical medicine, and some novel drugs and methods are developed. PMID:20175245

  15. In vitro management of hospital Pseudomonas aeruginosa biofilm using indigenous T7-like lytic phage.

    Science.gov (United States)

    Ahiwale, Sangeeta; Tamboli, Nilofer; Thorat, Kiran; Kulkarni, Rajendra; Ackermann, Hans; Kapadnis, Balasaheb

    2011-02-01

    Pseudomonas aeruginosa, a human pathogen capable of forming biofilm and contaminating medical settings, is responsible for 65% mortality in the hospitals all over the world. This study was undertaken to isolate lytic phages against biofilm forming Ps. aeruginosa hospital isolates and to use them for in vitro management of biofilms in the microtiter plate. Multidrug resistant strains of Ps. aeruginosa were isolated from the hospital environment in and around Pimpri-Chinchwad, Maharashtra by standard microbiological methods. Lytic phages against these strains were isolated from the Pavana river water by double agar layer plaque assay method. A wide host range phage bacterial virus Ps. aeruginosa phage (BVPaP-3) was selected. Electron microscopy revealed that BVPaP-3 phage is a T7-like phage and is a relative of phage species gh-1. A phage at MOI-0.001 could prevent biofilm formation by Ps. aeruginosa hospital strain-6(HS6) on the pegs within 24 h. It could also disperse pre-formed biofilms of all hospital isolates (HS1-HS6) on the pegs within 24 h. Dispersion of biofilm was studied by monitoring log percent reduction in cfu and log percent increase in pfu of respective bacterium and phage on the peg as well as in the well. Scanning electron microscopy confirmed that phage BVPaP-3 indeed causes biofilm reduction and bacterial cell killing. Laboratory studies prove that BVPaP-3 is a highly efficient phage in preventing and dispersing biofilms of Ps. aeruginosa. Phage BVPaP-3 can be used as biological disinfectant to control biofilm problem in medical devices.

  16. The Formation of Biofilms by Pseudomonas aeruginosa: A Review of the Natural and Synthetic Compounds Interfering with Control Mechanisms

    Directory of Open Access Journals (Sweden)

    Tsiry Rasamiravaka

    2015-01-01

    Full Text Available P. aeruginosa is an opportunistic pathogenic bacterium responsible for both acute and chronic infections. Beyond its natural resistance to many drugs, its ability to form biofilm, a complex biological system, renders ineffective the clearance by immune defense systems and antibiotherapy. The objective of this report is to provide an overview (i on P. aeruginosa biofilm lifestyle cycle, (ii on the main key actors relevant in the regulation of biofilm formation by P. aeruginosa including QS systems, GacS/GacA and RetS/LadS two-component systems and C-di-GMP-dependent polysaccharides biosynthesis, and (iii finally on reported natural and synthetic products that interfere with control mechanisms of biofilm formation by P. aeruginosa without affecting directly bacterial viability. Concluding remarks focus on perspectives to consider biofilm lifestyle as a target for eradication of resistant infections caused by P. aeruginosa.

  17. The catabolite repression control protein Crc plays a role in the development of antimicrobial-tolerant subpopulations in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Zhang, Lianbo; Chiang, Wen-Chi; Gao, Qingguo;

    2012-01-01

    . In the present study, we show that the catabolite repression control protein Crc regulates the metabolic state of Pseudomonas aeruginosa cells in biofilms, and plays an important role in the development of antimicrobial-tolerant subpopulations in P. aeruginosa biofilms.......Bacteria form complex surface-attached biofilm communities in nature. Biofilm cells differentiate into subpopulations which display tolerance towards antimicrobial agents. However, the signal transduction pathways regulating subpopulation differentiation in biofilms are largely unelucidated...

  18. Differentiation and distribution of colistin- and sodium dodecyl sulfate-tolerant cells in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Klausen, M; Ernst, RK;

    2007-01-01

    During Pseudomonas aeruginosa flow cell biofilm development, the cell population differentiates into a nonmotile subpopulation which forms microcolonies and a migrating subpopulation which eventually colonizes the top of the microcolonies, resulting in the development of mushroom-shaped multicell......During Pseudomonas aeruginosa flow cell biofilm development, the cell population differentiates into a nonmotile subpopulation which forms microcolonies and a migrating subpopulation which eventually colonizes the top of the microcolonies, resulting in the development of mushroom......-targeting antibacterial agents. All biofilm-associated cells were sensitive to the antibacterial agents when tested in standard plate assays. A mutation eliminating the production of type IV pili, and hence surface-associated motility, prevented the formation of regular mushroom-shaped structures in the flow cell...... that only the cap-forming subpopulation in biofilms treated with colistin expresses the pmr operon. These results suggest that increased antibiotic tolerance in biofilms may be a consequence of differentiation into distinct subpopulations with different phenotypic properties....

  19. The effects of D-Tyrosine combined with amikacin on the biofilms of Pseudomonas aeruginosa.

    Science.gov (United States)

    She, Pengfei; Chen, Lihua; Liu, Hongbo; Zou, Yaru; Luo, Zhen; Koronfel, Asmaa; Wu, Yong

    2015-09-01

    The biofilm formation of microorganisms causes persistent tissue infections resistant to treatment with antimicrobial agents. Pseudomonas aeruginosa is commonly isolated from the airways of patients with chronic fibrosis (CF) and often forms biofilms, which are extremely hard to eradicate and a major cause of mortality and morbidity. Recent studies have shown that D-amino acids (D-AAs) inhibited and disrupted biofilm formation by causing the release of the protein component of the polymeric matrix. However, the effects of D-AAs combined with common antibiotics on biofilms have rarely been studied. The current study first determined whether D-AAs disrupted the biofilms of PAO1 and the clinical airway isolates of P. aeruginosa. It was then determined whether combinations of D-Tyr (the most effective one) and the antibiotic amikacin (AMK) enhanced the activity against these biofilms. The results of the current study showed that D-Tyr is the most effective among those that disassemble the D-amino acids (D-leucine, D-methionine, D-Tyrptophan, and D-tryptophan), and D-Tyr at concentrations higher than 5 mM significantly reduced the biofilm biomass of P. aeruginosa (p < 0.05) without influencing bacterial growth. It was also revealed that D-Tyr improved the efficacy of AMK to combat P. aeruginosa biofilms, as indicated by a reduction in the minimal biofilm-inhibiting concentration (MBIC50 and MBIC90) without a change in the minimal inhibitory concentration (MIC) of planktonic bacteria. Thus, the findings indicated that D-Tyr supplementation overcame the resistance of P. aeruginosa biofilms to AMK, which might be helpful for preventing AMK overuse when this specific D-Tyr is recommended for combatting these biofilms. Also, toxicity of the liver and kidney from AMK could be potentially mitigated by co-delivery with D-Tyr. PMID:26188263

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

    Background There is a growing interest in studying the relationship between intrinsic resistance and biofilms resistance to drugs. However, the relationship still remains unclear in the macroscopic bacterial growth. Our study is to illuminate the change of bacterial drug resistance of gyrA mutant and active efflux pump during the development of Pseudomonas aeruginosa (P. aeruginosa) biofilms. Methods The strains of type Ⅱ topoisomerase gene mutant (gyrA mutant) and multidrug resistance (MDR) efflux pump were clinical isolates and detected by polymerase chain reaction (PCR). The process of bacterial biofilms development was observed by scanning electron microscope. Triparental mating experiments were performed to transfer report gene of green fluorescent protein (GFP) into P. aeruginosa biofilms strains and followed by analysis of bacterial survival rate between intrinsic resistance and biofilms resistance.Results The fluorescent strains with pGFPuv could develop mature biofilms on Teflon surface. Before a period of 72 hours, the survival rate of biofilms bacteria and intrinsic resistance strains in ciprofloxacin solution was significantly different (P0.05). The carbonyl cyanide m-chlorophenylhydrazone and azithromycin could significantly reduce the drug resistance of biofilm strains and efflux pump strains.Conclusions In the development of P. aeruginosa biofilms, the strains of gyrA mutation and MDR efflux could be conferred with new level of drug resistance. When co-cultured mutated strains with biofilm strains, biofilms may play a major role in bacterial resistance. But after 72 hours incubation (a mature biofilms had been developed), there was no clearly difference between the number of mutant strains and biofilm strains.

  1. Improved Biofilm Antimicrobial Activity of Polyethylene Glycol Conjugated Tobramycin Compared to Tobramycin in Pseudomonas aeruginosa Biofilms.

    Science.gov (United States)

    Du, Ju; Bandara, H M H N; Du, Ping; Huang, Hui; Hoang, Khang; Nguyen, Dang; Mogarala, Sri Vasudha; Smyth, Hugh D C

    2015-05-01

    The objective of this study was to develop a functionally enhanced antibiotic that would improve the therapeutic activity against bacterial biofilms. Tobramycin was chemically conjugated with polyethylene glycol (PEG) via site-specific conjugation to form PEGylated-tobramycin (Tob-PEG). The antibacterial efficacy of Tob-PEG, as compared to tobramycin, was assessed on the planktonic phase and biofilms phase of Pseudomonas aeruginosa. The minimum inhibitory concentration (MIC80) of Tob-PEG was higher (13.9 μmol/L) than that of tobramycin (1.4 μmol/L) in the planktonic phases. In contrast, the Tob-PEG was approximately 3.2-fold more effective in eliminating bacterial biofilms than tobramycin. Specifically, Tob-PEG had a MIC80 lower than those exhibited by tobramycin (27.8 μmol/L vs 89.8 μmol/L). Both confocal laser scanning microscopy and scanning electron microscopy further confirmed these data. Thus, modification of antimicrobials by PEGylation appears to be a promising approach for overcoming the bacterial resistance in the established biofilms of Pseudomonas aeruginosa.

  2. Inhibition of Pseudomonas aeruginosa biofilm formation on wound dressings.

    Science.gov (United States)

    Brandenburg, Kenneth S; Calderon, Diego F; Kierski, Patricia R; Brown, Amanda L; Shah, Nihar M; Abbott, Nicholas L; Schurr, Michael J; Murphy, Christopher J; McAnulty, Jonathan F; Czuprynski, Charles J

    2015-01-01

    Chronic nonhealing skin wounds often contain bacterial biofilms that prevent normal wound healing and closure and present challenges to the use of conventional wound dressings. We investigated inhibition of Pseudomonas aeruginosa biofilm formation, a common pathogen of chronic skin wounds, on a commercially available biological wound dressing. Building on prior reports, we examined whether the amino acid tryptophan would inhibit P. aeruginosa biofilm formation on the three-dimensional surface of the biological dressing. Bacterial biomass and biofilm polysaccharides were quantified using crystal violet staining or an enzyme linked lectin, respectively. Bacterial cells and biofilm matrix adherent to the wound dressing were visualized through scanning electron microscopy. D-/L-tryptophan inhibited P. aeruginosa biofilm formation on the wound dressing in a dose dependent manner and was not directly cytotoxic to immortalized human keratinocytes although there was some reduction in cellular metabolism or enzymatic activity. More importantly, D-/L-tryptophan did not impair wound healing in a splinted skin wound murine model. Furthermore, wound closure was improved when D-/L-tryptophan treated wound dressing with P. aeruginosa biofilms were compared with untreated dressings. These findings indicate that tryptophan may prove useful for integration into wound dressings to inhibit biofilm formation and promote wound healing.

  3. Role of mutation in Pseudomonas aeruginosa biofilm development.

    Directory of Open Access Journals (Sweden)

    Tim C R Conibear

    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

  4. The effects of D-Tyrosine combined with amikacin on the biofilms of Pseudomonas aeruginosa.

    Science.gov (United States)

    She, Pengfei; Chen, Lihua; Liu, Hongbo; Zou, Yaru; Luo, Zhen; Koronfel, Asmaa; Wu, Yong

    2015-09-01

    The biofilm formation of microorganisms causes persistent tissue infections resistant to treatment with antimicrobial agents. Pseudomonas aeruginosa is commonly isolated from the airways of patients with chronic fibrosis (CF) and often forms biofilms, which are extremely hard to eradicate and a major cause of mortality and morbidity. Recent studies have shown that D-amino acids (D-AAs) inhibited and disrupted biofilm formation by causing the release of the protein component of the polymeric matrix. However, the effects of D-AAs combined with common antibiotics on biofilms have rarely been studied. The current study first determined whether D-AAs disrupted the biofilms of PAO1 and the clinical airway isolates of P. aeruginosa. It was then determined whether combinations of D-Tyr (the most effective one) and the antibiotic amikacin (AMK) enhanced the activity against these biofilms. The results of the current study showed that D-Tyr is the most effective among those that disassemble the D-amino acids (D-leucine, D-methionine, D-Tyrptophan, and D-tryptophan), and D-Tyr at concentrations higher than 5 mM significantly reduced the biofilm biomass of P. aeruginosa (p biofilms, as indicated by a reduction in the minimal biofilm-inhibiting concentration (MBIC50 and MBIC90) without a change in the minimal inhibitory concentration (MIC) of planktonic bacteria. Thus, the findings indicated that D-Tyr supplementation overcame the resistance of P. aeruginosa biofilms to AMK, which might be helpful for preventing AMK overuse when this specific D-Tyr is recommended for combatting these biofilms. Also, toxicity of the liver and kidney from AMK could be potentially mitigated by co-delivery with D-Tyr.

  5. A characterization of DNA release in Pseudomonas aeruginosa cultures and biofilms

    DEFF Research Database (Denmark)

    Allesen-Holm, Marie; Barken, Kim Bundvig; Yang, Liang;

    2006-01-01

    Pseudomonas aeruginosa produces extracellular DNA which functions as a cell-to-cell interconnecting matrix component in biofilms. Comparison of extracellular DNA and chromosomal DNA by the use of polymerase chain reaction and Southern analysis suggested that the extracellular DNA is similar......-type P. aeruginosa biofilms stained with different DNA stains suggested that the extracellular DNA is located primarily in the stalks of mushroom-shaped multicellular structures, with a high concentration especially in the outer part of the stalks forming a border between the stalk-forming bacteria...

  6. The impact of quorum sensing and swarming motility on Pseudomonas aeruginosa biofilm formation is nutritionally conditional

    DEFF Research Database (Denmark)

    Shrout, J.D.; Chopp, D.L.; Just, C.L.;

    2006-01-01

    The role of quorum sensing in Pseudomonas aeruginosa biofilm formation is unclear. Some researchers have shown that quorum sensing is important for biofilm development, while others have indicated it has little or no role. In this study, the contribution of quorum sensing to biofilm development...... was found to depend upon the nutritional environment. Depending upon the carbon source, quorum-sensing mutant strains (lasIrhlI and lasRrhlR) either exhibited a pronounced defect early in biofilm formation or formed biofilms identical to the wild-type strain. Quorum sensing was then shown to exert its...... nutritionally conditional control of biofilm development through regulation of swarming motility. Examination of pilA and fliM mutant strains further supported the role of swarming motility in biofilm formation. These data led to a model proposing that the prevailing nutritional conditions dictate...

  7. Pseudomonas aeruginosa biofilm growth inhibition on medical plastic materials by immobilized esterases and acylase.

    Science.gov (United States)

    Kisch, Johannes Martin; Utpatel, Christian; Hilterhaus, Lutz; Streit, Wolfgang R; Liese, Andreas

    2014-09-01

    Biofilms are matrix-encapsulated cell aggregates that cause problems in technical and health-related areas; for example, 65 % of all human infections are biofilm associated. This is mainly due to their ameliorated resistance against antimicrobials and immune systems. Pseudomonas aeruginosa, a biofilm-forming organism, is commonly responsible for nosocomial infections. Biofilm development is partly mediated by signal molecules, such as acyl-homoserine lactones (AHLs) in Gram-negative bacteria. We applied horse liver esterase, porcine kidney acylase, and porcine liver esterase; these can hydrolyze AHLs, thereby inhibiting biofilm formation. As biofilm infections are often related to foreign material introduced into the human body, we immobilized the enzymes on medical plastic materials. Biofilm formation was quantified by Crystal Violet staining and confocal laser scanning microscopy, revealing up to 97 % (on silicone), 54 % (on polyvinyl chloride), and 77 % (on polyurethane) reduced biomass after 68 h growth.

  8. Ambroxol inhibits mucoid conversion of Pseudomonas aeruginosa and contributes to the bactericidal activity of ciprofloxacin against mucoid P. aeruginosa biofilms.

    Science.gov (United States)

    Wang, Wenlei; Yu, Jialin; He, Yu; Wang, Zhengli; Li, Fang

    2016-07-01

    Pseudomonas aeruginosa is an opportunistic human pathogen that can cause severe infections in immunocompromised individuals. Because it forms biofilms, which protect against host immune attack and increase resistance to conventional antibiotics, mucoid P. aeruginosa is nearly impossible to eradicate. Moreover, mucoid conversion of P. aeruginosa in cystic fibrosis (CF) patients leads to poor outcomes. This conversion is mainly due to mucA gene mutation, which is thought to be induced by polymorphonuclear leukocytes (PMNs) and the reactive oxygen species they release. Ambroxol, a mucolytic agent with antioxidant characteristics, is used clinically, and this compound has recently been demonstrated to possess anti-biofilm properties. In this study, we found that ambroxol inhibits the H2 O2 -mediated conversion of P. aeruginosa from a non-mucoid to a mucoid phenotype, an effect that is due to its antioxidant property against H2 O2 . Furthermore, the bactericidal activity of ciprofloxacin against mucoid P. aeruginosa biofilms was increased in vitro when used in combination with ambroxol.

  9. Ambroxol inhibits mucoid conversion of Pseudomonas aeruginosa and contributes to the bactericidal activity of ciprofloxacin against mucoid P. aeruginosa biofilms.

    Science.gov (United States)

    Wang, Wenlei; Yu, Jialin; He, Yu; Wang, Zhengli; Li, Fang

    2016-07-01

    Pseudomonas aeruginosa is an opportunistic human pathogen that can cause severe infections in immunocompromised individuals. Because it forms biofilms, which protect against host immune attack and increase resistance to conventional antibiotics, mucoid P. aeruginosa is nearly impossible to eradicate. Moreover, mucoid conversion of P. aeruginosa in cystic fibrosis (CF) patients leads to poor outcomes. This conversion is mainly due to mucA gene mutation, which is thought to be induced by polymorphonuclear leukocytes (PMNs) and the reactive oxygen species they release. Ambroxol, a mucolytic agent with antioxidant characteristics, is used clinically, and this compound has recently been demonstrated to possess anti-biofilm properties. In this study, we found that ambroxol inhibits the H2 O2 -mediated conversion of P. aeruginosa from a non-mucoid to a mucoid phenotype, an effect that is due to its antioxidant property against H2 O2 . Furthermore, the bactericidal activity of ciprofloxacin against mucoid P. aeruginosa biofilms was increased in vitro when used in combination with ambroxol. PMID:27102839

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

    OpenAIRE

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

    2005-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Mikuniya,Takeshi

    2005-10-01

    Full Text Available

    Ulifloxacin is the active form of the prodrug prulifloxacin and shows a highly potent antipseudomonal activity. In this study, we examined the combined effect of fosfomycin and ulifloxacin against Pseudomonas aeruginosa (P. aeruginosa growing in a biofilm using a modified Robbins device with artificial urine, and compared it to that of the combination of fosfomycin and ciprofloxacin or levofloxacin. An ATP bioluminescence assay was used to evaluate the antibacterial activity of the agents against sessile cells in a mature biofilm developed on a silicon disk. The total bioactivity of P. aeruginosa growing in a biofilm that had not been fully eradicated by fosfomycin or any of the fluoroquinolones alone at 10 times the MIC decreased after combination treatment with fosfomycin and fluoroquinolones. Morphological changes occurred in a time-dependent fashion; namely, swollen and/or rounding cells emerged within a couple of hours after combination treatment, marking the initial stage in the process leading to the destruction of the biofilms. We could not find any difference among the 3 fluoroquinolones with regard to their synergistic effects when administered with fosfomycin. The combination treatment of fosfomycin and fluoroquinolones with highly potent antipseudomonal activities was effective in eradicating sessile cells of P. aeruginosa in the biofilm and promises to be beneficial against biofilm-associated infectious diseases.

  12. Sputum containing zinc enhances carbapenem resistance, biofilm formation and virulence of Pseudomonas aeruginosa.

    Science.gov (United States)

    Marguerettaz, Mélanie; Dieppois, Guennaëlle; Que, Yok Ai; Ducret, Véréna; Zuchuat, Sandrine; Perron, Karl

    2014-12-01

    Pseudomonas aeruginosa chronic lung infections are the leading cause of mortality in cystic fibrosis patients, a serious problem which is notably due to the numerous P. aeruginosa virulence factors, to its ability to form biofilms and to resist the effects of most antibiotics. Production of virulence factors and biofilm formation by P. aeruginosa is highly coordinated through complex regulatory systems. We recently found that CzcRS, the zinc and cadmium-specific two-component system is not only involved in metal resistance, but also in virulence and carbapenem antibiotic resistance in P. aeruginosa. Interestingly, zinc has been shown to be enriched in the lung secretions of cystic fibrosis patients. In this study, we investigated whether zinc might favor P. aeruginosa pathogenicity using an artificial sputum medium to mimic the cystic fibrosis lung environment. Our results show that zinc supplementation triggers a dual P. aeruginosa response: (i) it exacerbates pathogenicity by a CzcRS two-component system-dependent mechanism and (ii) it stimulates biofilm formation by a CzcRS-independent mechanism. Furthermore, P. aeruginosa cells embedded in these biofilms exhibited increased resistance to carbapenems. We identified a novel Zn-sensitive regulatory circuit controlling the expression of the OprD porin and modifying the carbapenem resistance profile. Altogether our data demonstrated that zinc levels in the sputum of cystic fibrosis patients might aggravate P. aeruginosa infection. Targeting zinc levels in sputum would be a valuable strategy to curb the increasing burden of P. aeruginosa infections in cystic fibrosis patients. PMID:25448466

  13. 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.

  14. Influence of glyphosate in planktonic and biofilm growth of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Ilana Schneider Lima

    2014-09-01

    Full Text Available This study evaluated the impact of different concentrations of glyphosate (Rondup® on planktonic and biofilm growth of P. aeruginosa. Aerobic and anaerobic cultures of P. aeruginosa ATCC®15442 inoculated in MHB + glyphosate (0.845 ppm, 1.690 ppm, 8.45 ppm, 16.90 ppm, 84.50 ppm, 169 ppm, 845 ppm, and 1690 ppm and cultured in normoxia and anoxia, following their OD560nm every hour for 24 h. Biofilms of adapted cells were formed in the presence of glyphosate (0.845 to 1690 ppm in normoxia and anoxia for 36 h. Glyphosate at concentrations higher than 84.5 ppm reduces the cell density of planktonic aerobic cultures (p 0.05, and more pronounced over 169 ppm. Anaerobic biofilms have their growth more readily favored (p < 0.05, regardless of concentration. In a concentration-dependent manner, glyphosate interferes with the growth ability of P. aeruginosa ATCC®15442.

  15. 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

  16. Subinhibitory concentration of ciprofloxacin targets quorum sensing system of Pseudomonas aeruginosa causing inhibition of biofilm formation & reduction of virulence

    Directory of Open Access Journals (Sweden)

    Parul Gupta

    2016-01-01

    Results: Sub-minimum inhibitory concentration (sub-MIC of CIP significantly reduced the motility of P. aeruginosa stand and strain and clinical isolates and affected biofilm forming capacity. Production of protease, elastase, siderophore, alginate, and rhamnolipid was also significantly reduced by CIP. Interpretation & conclusions: Reduction in virulence factors and biofilm formation was due to inhibition of QS mechanism which was indicated by reduced production of QS signal molecules by P. aeruginosa in presence of subinhibitory concentration of CIP.

  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

    distinguishable stages are observed during bacterial biofilm development. Biofilm formation is shown to be coordinated by EPS production, cell migration, subpopulation differentiation and interactions. However, the ways these different factors affect each other and contribute to community structural......Bacteria form surface attached biofilm communities as one of the most important survival strategies in nature. Biofilms consist of water, bacterial cells and a wide range of self‐generated extracellular polymeric substances (EPS). Biofilm formation is a dynamic self‐assembly process and several...... 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...

  18. Impairment of Pseudomonas aeruginosa Biofilm Resistance to Antibiotics by Combining the Drugs with a New Quorum-Sensing Inhibitor

    Science.gov (United States)

    Lajoie, Barbora; El Hage, Salome; Baziard, Genevieve; Roques, Christine

    2015-01-01

    Pseudomonas aeruginosa plays an important role in chronic lung infections among patients with cystic fibrosis (CF) through its ability to form antibiotic-resistant biofilms. In P. aeruginosa, biofilm development and the production of several virulence factors are mainly regulated by the rhl and las quorum-sensing (QS) systems, which are controlled by two N-acyl-homoserine lactone signal molecules. In a previous study, we discovered an original QS inhibitor, N-(2-pyrimidyl)butanamide, called C11, based on the structure of C4-homoserine lactone, and found that it is able to significantly inhibit P. aeruginosa biofilm formation. However, recent data indicate that P. aeruginosa grows under anaerobic conditions and forms biofilms in the lungs of CF patients that are denser and more robust than those formed under aerobic conditions. Our confocal microscopy observations of P. aeruginosa biofilms developed under aerobic and anaerobic conditions confirmed that the biofilms formed under these two conditions have radically different architectures. C11 showed significant dose-dependent antibiofilm activity on biofilms grown under both aerobic and anaerobic conditions, with a greater inhibitory effect being seen under conditions of anaerobiosis. Gene expression analyses performed by quantitative reverse transcriptase PCR showed that C11 led to the significant downregulation of rhl QS regulatory genes but also to the downregulation of both las QS regulatory genes and QS system-regulated virulence genes, rhlA and lasB. Furthermore, the activity of C11 in combination with antibiotics against P. aeruginosa biofilms was tested, and synergistic antibiofilm activity between C11 and ciprofloxacin, tobramycin, and colistin was obtained under both aerobic and anaerobic conditions. This study demonstrates that C11 may increase the efficacy of treatments for P. aeruginosa infections by increasing the susceptibility of biofilms to antibiotics and by attenuating the pathogenicity of the

  19. Impairment of Pseudomonas aeruginosa Biofilm Resistance to Antibiotics by Combining the Drugs with a New Quorum-Sensing Inhibitor.

    Science.gov (United States)

    Furiga, Aurelie; Lajoie, Barbora; El Hage, Salome; Baziard, Genevieve; Roques, Christine

    2016-03-01

    Pseudomonas aeruginosa plays an important role in chronic lung infections among patients with cystic fibrosis (CF) through its ability to form antibiotic-resistant biofilms. In P. aeruginosa, biofilm development and the production of several virulence factors are mainly regulated by the rhl and las quorum-sensing (QS) systems, which are controlled by two N-acyl-homoserine lactone signal molecules. In a previous study, we discovered an original QS inhibitor, N-(2-pyrimidyl)butanamide, called C11, based on the structure of C4-homoserine lactone, and found that it is able to significantly inhibit P. aeruginosa biofilm formation. However, recent data indicate that P. aeruginosa grows under anaerobic conditions and forms biofilms in the lungs of CF patients that are denser and more robust than those formed under aerobic conditions. Our confocal microscopy observations of P. aeruginosa biofilms developed under aerobic and anaerobic conditions confirmed that the biofilms formed under these two conditions have radically different architectures. C11 showed significant dose-dependent antibiofilm activity on biofilms grown under both aerobic and anaerobic conditions, with a greater inhibitory effect being seen under conditions of anaerobiosis. Gene expression analyses performed by quantitative reverse transcriptase PCR showed that C11 led to the significant downregulation of rhl QS regulatory genes but also to the downregulation of both las QS regulatory genes and QS system-regulated virulence genes, rhlA and lasB. Furthermore, the activity of C11 in combination with antibiotics against P. aeruginosa biofilms was tested, and synergistic antibiofilm activity between C11 and ciprofloxacin, tobramycin, and colistin was obtained under both aerobic and anaerobic conditions. This study demonstrates that C11 may increase the efficacy of treatments for P. aeruginosa infections by increasing the susceptibility of biofilms to antibiotics and by attenuating the pathogenicity of the

  20. Potential of Ocimum basilicum L. and Salvia officinalis L. essential oils against biofilms of P. aeruginosa clinical isolates.

    Science.gov (United States)

    Stojanović-Radić, Z; Pejcić, M; Stojanović, N; Sharifi-Rad, J; Stanković, N

    2016-08-29

    Biofilms are complex communities of microorganisms, responsible for more than 60% of the chronic human infections and they represent one of the leading concerns in medicine. Pseudomonas aeruginosa is human pathogenic bacteria which causes numerous diseases and is known for its ability to produce biofilm. Ocimum basilicum L. (basil) and Salvia officinalis L. (sage) are widely used plants in traditional medicine for the treatment of different conditions. Therefore, the aim of this study was to investigate the potential of basil and sage essential oils against P. aeruginosa biofilm producing strains. The efficacy of two essential oils on P. aeruginosa biofilm forming ability was determined using crystal violet method. Out of 15 strains isolated from different clinical biological samples, two were strong, 11 moderate and one weak biofilm producer. Good efficacy of sage essential oil towards strong and weak biofilm producers, but not of basil essential oil, was observed. In the case of moderate biofilm producers, 81.8% showed lower biofilm production after incubation with the sage oil, while 63.6% showed the reduction of biofilm production after basil essential oil treatment. The obtained results showed high potential of both oils for the treatment of persistent infections caused by Pseudomonas aeruginosa biofilms.

  1. Potential of Ocimum basilicum L. and Salvia officinalis L. essential oils against biofilms of P. aeruginosa clinical isolates.

    Science.gov (United States)

    Stojanović-Radić, Z; Pejcić, M; Stojanović, N; Sharifi-Rad, J; Stanković, N

    2016-01-01

    Biofilms are complex communities of microorganisms, responsible for more than 60% of the chronic human infections and they represent one of the leading concerns in medicine. Pseudomonas aeruginosa is human pathogenic bacteria which causes numerous diseases and is known for its ability to produce biofilm. Ocimum basilicum L. (basil) and Salvia officinalis L. (sage) are widely used plants in traditional medicine for the treatment of different conditions. Therefore, the aim of this study was to investigate the potential of basil and sage essential oils against P. aeruginosa biofilm producing strains. The efficacy of two essential oils on P. aeruginosa biofilm forming ability was determined using crystal violet method. Out of 15 strains isolated from different clinical biological samples, two were strong, 11 moderate and one weak biofilm producer. Good efficacy of sage essential oil towards strong and weak biofilm producers, but not of basil essential oil, was observed. In the case of moderate biofilm producers, 81.8% showed lower biofilm production after incubation with the sage oil, while 63.6% showed the reduction of biofilm production after basil essential oil treatment. The obtained results showed high potential of both oils for the treatment of persistent infections caused by Pseudomonas aeruginosa biofilms. PMID:27585258

  2. In vitro activity of ceftolozane/tazobactam against clinical isolates of Pseudomonas aeruginosa in the planktonic and biofilm states.

    Science.gov (United States)

    Velez Perez, Antonio L; Schmidt-Malan, Suzannah M; Kohner, Peggy C; Karau, Melissa J; Greenwood-Quaintance, Kerryl E; Patel, Robin

    2016-07-01

    Pseudomonas aeruginosa causes a variety of life-threatening infections, some of which are associated with planktonic and others with biofilm states. Herein, we tested the combination of the novel cephalosporin, ceftolozane, with the β-lactamase inhibitor, tazobactam, against planktonic and biofilm forms of 54 clinical isolates of P. aeruginosa, using cefepime as a comparator. MIC values were determined following Clinical and Laboratory Standards Institute (CLSI) guidelines. Minimum biofilm inhibitory concentration (MBIC) values were determined using biofilm-laden pegged lids incubated in antimicrobial challenge plates containing varying concentrations of ceftolozane/tazobactam. Pegged lids were then incubated in growth recovery plates containing cation-adjusted Mueller-Hinton broth to determine the minimum biofilm bactericidal concentration (MBBC). Ceftolozane/tazobactam was highly active against planktonic P. aeruginosa, with all 54 isolates studied testing susceptible (MIC ≤4/4μg/mL). On the other hand, 51/54 biofilm P. aeruginosa had MBICs ≥16/4μg/mL, and all 54 isolates had MBBCs >32μg/mL. Of the 54 isolates, 45 (83.3%) tested susceptible to cefepime, with the MIC50/MIC90 being 4/16μg/mL, respectively, and the MBIC90 and MBBC90 both being >256μg/mL. Although ceftolozane/tazobactam is a promising antimicrobial agent for the treatment of P. aeruginosa infections, it is not highly active against P. aeruginosa biofilms. PMID:27130477

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

    DEFF Research Database (Denmark)

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

    2001-01-01

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

  4. 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.

  5. 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

    2016-01-01

    Microbial biofilm are communities of surface-adhered cells enclosed in a matrix of extracellular polymeric substances. Extensive use of antibiotics to treat biofilm associated infections has led to the emergence of multiple drug resistant strains. Pseudomonas aeruginosa is recognised as a model biofilm forming pathogenic bacterium. Vitexin, a polyphenolic group of phytochemical with antimicrobial property, has been studied for its antibiofilm potential against Pseudomonas aeruginosa in 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. PMID:27000525

  6. The immune system vs. Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

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

    2010-01-01

    in the planktonic state. Accordingly, much less is known about the immune responses to the presence of biofilm-based infections (which is probably also due to the relatively short period of time in which the immune response to biofilms has been studied). Nevertheless, more recent in vivo and in vitro studies have...... revealed both innate as well as adaptive immune responses to biofilms. On the other hand, measures launched by biofilm bacteria to achieve protection against the various immune responses have also been demonstrated. Whether particular immune responses to biofilm infections exist remains to be firmly...... established. However, because biofilm infections are often persistent (or chronic), an odd situation appears with the simultaneous activation of both arms of the host immune response, neither of which can eliminate the biofilm pathogen, but instead, in synergy, causes collateral tissue damage. Although...

  7. Flagellum-Mediated Biofilm Defense Mechanisms of Pseudomonas aeruginosa against Host-Derived Lactoferrin ▿

    Science.gov (United States)

    Leid, Jeff G.; Kerr, Mathias; Selgado, Candice; Johnson, Chelsa; Moreno, Gabriel; Smith, Alyssa; Shirtliff, Mark E.; O'Toole, George A.; Cope, Emily K.

    2009-01-01

    Chronic infection with the gram-negative organism Pseudomonas aeruginosa is a leading cause of morbidity and mortality in human patients, despite high doses of antibiotics used to treat the various diseases this organism causes. These infections are chronic because P. aeruginosa readily forms biofilms, which are inherently resistant to antibiotics as well as the host's immune system. Our laboratory has been investigating specific mutations in P. aeruginosa that regulate biofilm bacterial susceptibility to the host. To continue our investigation of the role of genetics in bacterial biofilm host resistance, we examined P. aeruginosa biofilms that lack the flgK gene. This mutant lacks flagella, which results in defects in early biofilm development (up to 36 h). For these experiments, the flgK-disrupted strain and the parental strain (PA14) were used in a modified version of the 96-well plate microtiter assay. Biofilms were challenged with freshly isolated human leukocytes for 4 to 6 h and viable bacteria enumerated by CFU. Subsequent to the challenge, both mononuclear cells (monocytes and lymphocytes) and neutrophils, along with tumor necrosis factor alpha (TNF-α), were required for optimal killing of the flgK biofilm bacteria. We identified a cytokine cross talk network between mononuclear cells and neutrophils that was essential to the production of lactoferrin and bacterial killing. Our data suggest that TNF-α is secreted from mononuclear cells, causing neutrophil activation, resulting in the secretion of bactericidal concentrations of lactoferrin. These results extend previous studies of the importance of lactoferrin in the innate immune defense against bacterial biofilms. PMID:19651866

  8. 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...

  9. Alginate overproduction affects Pseudomonas aeruginosa biofilm structure and function

    DEFF Research Database (Denmark)

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

    2001-01-01

    -resistant communities of microorganisms organized in biofilms. Although biofilm formation and the conversion to mucoidy are both important aspects of CF pathogenesis, the relationship between them is at the present unclear. In this study, we report that the overproduction of alginate affects biofilm development...... on an abiotic surface. Biofilms formed by an alginate- overproducing strain exhibit a highly structured architecture and are significantly more resistant to the antibiotic tobramycin than a biofilm formed by an isogenic nonmucoid strain. These results suggest that an important consequence of the conversion...... to mucoidy is an altered biofilm architecture that shows increasing resistance to antimicrobial treatments....

  10. Mannitol Does Not Enhance Tobramycin Killing of Pseudomonas aeruginosa in a Cystic Fibrosis Model System of Biofilm Formation.

    Directory of Open Access Journals (Sweden)

    Katherine E Price

    Full Text Available Cystic Fibrosis (CF is a human genetic disease that results in the accumulation of thick, sticky mucus in the airways, which results in chronic, life-long bacterial biofilm infections that are difficult to clear with antibiotics. Pseudomonas aeruginosa lung infection is correlated with worsening lung disease and P. aeruginosa transitions to an antibiotic tolerant state during chronic infections. Tobramycin is an aminoglycoside currently used to combat lung infections in individuals with CF. While tobramycin is effective at eradicating P. aeruginosa in the airways of young patients, it is unable to completely clear the chronic P. aeruginosa infections in older patients. A recent report showed that co-addition of tobramycin and mannitol enhanced killing of P. aeruginosa grown in vitro as a biofilm on an abiotic surface. Here we employed a model system of bacterial biofilms formed on the surface of CF-derived airway cells to determine if mannitol would enhance the antibacterial activity of tobramycin against P. aeruginosa grown on a more clinically relevant surface. Using this model system, which allows the growth of robust biofilms with high-level antibiotic tolerance analogous to in vivo biofilms, we were unable to find evidence for enhanced antibacterial activity of tobramycin with the addition of mannitol, supporting the observation that this type of co-treatment failed to reduce the P. aeruginosa bacterial load in a clinical setting.

  11. The implication of Pseudomonas aeruginosa biofilms in infections

    DEFF Research Database (Denmark)

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

    2011-01-01

    Biofilm formation by bacteria is recognized as a major problem in chronic infections due to their recalcitrance against the immune defense and available antibiotic treatment schemes. The opportunistic pathogen Pseudomonas aeruginosa has drawn special attention in this regard due to its severity...... of infection in the lungs of cystic fibrosis patients and in chronic wounds. In this review we address the molecular basis of biofilm development by P. aeruginosa as well as the mechanisms employed by this bacterium in the increased tolerance displayed against antimicrobials. The complex build......-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...

  12. 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 o...... treatment strategies where the underlying targets are less prone for resistance development as bacteria, in retrospect, have a unique ability to evade the actions of classic antibiotics.......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...

  13. Anti-Biofilm and Immunomodulatory Activities of Peptides That Inhibit Biofilms Formed by Pathogens Isolated from Cystic Fibrosis Patients.

    Science.gov (United States)

    de la Fuente-Núñez, César; Mansour, Sarah C; Wang, Zhejun; Jiang, Lucy; Breidenstein, Elena B M; Elliott, Melissa; Reffuveille, Fany; Speert, David P; Reckseidler-Zenteno, Shauna L; Shen, Ya; Haapasalo, Markus; Hancock, Robert E W

    2014-01-01

    Cystic fibrosis (CF) patients often acquire chronic respiratory tract infections due to Pseudomonas aeruginosa and Burkholderia cepacia complex (Bcc) species. In the CF lung, these bacteria grow as multicellular aggregates termed biofilms. Biofilms demonstrate increased (adaptive) resistance to conventional antibiotics, and there are currently no available biofilm-specific therapies. Using plastic adherent, hydroxyapatite and flow cell biofilm models coupled with confocal and scanning electron microscopy, it was demonstrated that an anti-biofilm peptide 1018 prevented biofilm formation, eradicated mature biofilms and killed biofilms formed by a wide range of P. aeruginosa and B. cenocepacia clinical isolates. New peptide derivatives were designed that, compared to their parent peptide 1018, showed similar or decreased anti-biofilm activity against P. aeruginosa biofilms, but increased activity against biofilms formed by the Gram-positive bacterium methicillin resistant Staphylococcus aureus. In addition, some of these new peptide derivatives retained the immunomodulatory activity of 1018 since they induced the production of the chemokine monocyte chemotactic protein-1 (MCP-1) and suppressed lipopolysaccharide-mediated tumor necrosis factor-α (TNF-α) production by human peripheral blood mononuclear cells (PBMC) and were non-toxic towards these cells. Peptide 1018 and its derivatives provide promising leads for the treatment of chronic biofilm infections and hyperinflammatory lung disease in CF patients.

  14. Anti-Biofilm and Immunomodulatory Activities of Peptides That Inhibit Biofilms Formed by Pathogens Isolated from Cystic Fibrosis Patients

    Directory of Open Access Journals (Sweden)

    César de la Fuente-Núñez

    2014-10-01

    Full Text Available Cystic fibrosis (CF patients often acquire chronic respiratory tract infections due to Pseudomonas aeruginosa and Burkholderia cepacia complex (Bcc species. In the CF lung, these bacteria grow as multicellular aggregates termed biofilms. Biofilms demonstrate increased (adaptive resistance to conventional antibiotics, and there are currently no available biofilm-specific therapies. Using plastic adherent, hydroxyapatite and flow cell biofilm models coupled with confocal and scanning electron microscopy, it was demonstrated that an anti-biofilm peptide 1018 prevented biofilm formation, eradicated mature biofilms and killed biofilms formed by a wide range of P. aeruginosa and B. cenocepacia clinical isolates. New peptide derivatives were designed that, compared to their parent peptide 1018, showed similar or decreased anti-biofilm activity against P. aeruginosa biofilms, but increased activity against biofilms formed by the Gram-positive bacterium methicillin resistant Staphylococcus aureus. In addition, some of these new peptide derivatives retained the immunomodulatory activity of 1018 since they induced the production of the chemokine monocyte chemotactic protein-1 (MCP-1 and suppressed lipopolysaccharide-mediated tumor necrosis factor-α (TNF-α production by human peripheral blood mononuclear cells (PBMC and were non-toxic towards these cells. Peptide 1018 and its derivatives provide promising leads for the treatment of chronic biofilm infections and hyperinflammatory lung disease in CF patients.

  15. Inactivation of Pseudomonas aeruginosa biofilm by dense phase carbon dioxide.

    Science.gov (United States)

    Mun, Sungmin; Jeong, Jin-Seong; Kim, Jaeeun; Lee, Youn-Woo; Yoon, Jeyong

    2009-01-01

    Dense phase carbon dioxide (DPCD) is one of the most promising techniques available to control microorganisms as a non-thermal disinfection method. However, no study on the efficiency of biofilm disinfection using DPCD has been reported. The efficiency of DPCD in inactivating Pseudomonas aeruginosa biofilm, which is known to have high antimicrobial resistance, was thus investigated. P. aeruginosa biofilm, which was not immersed in water but was completely wet, was found to be more effectively inactivated by DPCD treatment, achieving a 6-log reduction within 7 min. The inactivation efficiency increased modestly with increasing pressure and temperature. This study also reports that the water-unimmersed condition is one of the most important operating parameters in achieving efficient biofilm control by DPCD treatment. In addition, observations by confocal laser scanning microscopy revealed that DPCD treatment not only inactivated biofilm cells on the glass coupons but also caused detachment of the biofilm following weakening of its structure as a result of the DPCD treatment; this is an added benefit of DPCD treatment.

  16. Effect of plant phenolic compounds on biofilm formation by Pseudomonas aeruginosa.

    Science.gov (United States)

    Plyuta, Vladimir; Zaitseva, Julia; Lobakova, Elena; Zagoskina, Natalia; Kuznetsov, Alexander; Khmel, Inessa

    2013-11-01

    In the natural environment, bacteria predominantly exist in matrix-enclosed multicellular communities associated with various surfaces, referred to as biofilms. Bacteria in biofilms are extremely resistant to antibacterial agents thus causing serious problems for antimicrobial therapy. In this study, we showed that different plant phenolic compounds, at concentrations that did not or weakly suppressed bacterial growth, increased the capacity of Pseudomonas aeruginosa PAO1 to form biofilms. Biofilm formation of P. aeruginosa PAO1 was enhanced 3- to 7-fold under the action of vanillin and epicatechin, and 2- to 2.5-fold in the presence of 4-hydroxybenzoic, gallic, cinnamic, sinapic, ferulic, and chlorogenic acids. At higher concentrations, these compounds displayed an inhibiting effect. Similar experiments carried out for comparison with Agrobacterium tumefaciens C58 showed the same pattern. Vanillin, 4-hydroxybenzoic, and gallic acids at concentrations within the range of 40 to 400 μg/mL increased the production of N-3-oxo-dodecanoyl-homoserine lactone in P. aeruginosa PAO1 which suggests a possible relationship between stimulation of biofilm formation and Las Quorum Sensing system of this bacterium. Using biosensors to detect N-acyl-homoserine lactones (AHL), we demonstrated that the plant phenolics studied did not mimic AHLs. PMID:23594262

  17. An effective antibiofilm agent against Pseudomonas aeruginosa biofilm from traditional Thai herbal recipes used for wound treatments.

    Science.gov (United States)

    Chusri, Sasitorn; Jittanon, Wittaya; Maneenoon, Katesarin; Voravuthikunchai, Supayang Piyawan

    2013-10-01

    The presence of bacterial biofilm, particularly formed by Pseudomonas aeruginosa, has been considered an important factor responsible for wound chronicity. The objective of this study was to investigate the antibiofilm activity of water and ethanol extracts obtained from three traditional herbal recipes (THR-SK004, THR-SK010, and THR-SK011) on biofilm formation and on mature biofilm of a reference strain of P. aeruginosa. The effects of the extracts on the biofilm mass were evaluated by using crystal violet (CV) assay. The respiratory activity of preformed biofilm of P. aeruginosa after treatment with the extract was determined by MTT reduction assay. Scanning electron microscopy was used to furnish images of biofilm reduction after the recipe treatment. Tested ethanol extracts displayed antibiofilm activity, but the water extracts exhibited low biofilm inhibition activity at the tested concentrations. Remarkable reduction in biofilm formation of P. aeruginosa was found after treatment with the THR-SK010 ethanol extract (THR-SK010E). Treatments with this extract resulted in prevention of biofilm formation of P. aeruginosa on both polystyrene and glass surfaces. Almost 50% reduction in the bacterial metabolic activity in the preformed biofilm was seen after exposure to the extract-supplemented buffer for 12 hr. After a 24-hr treatment with THR-SK010E at 62.5 μg/ml, 97.3% of the preformed biofilms were destroyed. Promising antibiofilm activity was displayed by the THR-SK010 ethanol extract, suggesting further investigation to explore the possible utilization of the herbal recipe as an antibiofilm agent, especially for wound treatment. PMID:23600560

  18. Activity of ozonated water and ozone against Staphylococcus aureus and Pseudomonas aeruginosa biofilms

    Science.gov (United States)

    Bialoszewski, Dariusz; Pietruczuk-Padzik, Anna; Kalicinska, Agnieszka; Bocian, Ewa; Czajkowska, Magdalena; Bukowska, Bozena; Tyski, Stefan

    2011-01-01

    Summary Background The known bactericidal properties of ozone have not been checked in relation to its action on bacterial biofilms. This is especially true of ozonated fluids. The aim of this study was to investigate the bactericidal activity of ozonated water and that of a mixture of ozone and oxygen against biofilms. Material/Methods Eighteen clinical strains of Staphylococcus aureus and Pseudomonas aeruginosa exhibiting various levels of antibiotic sensitivity were investigated. Bacteria were cultured in biofilm form on polystyrene titration plates for periods of 2 to 72 hours. The biofilms formed in this way were exposed to in statu nascendi ozonated water produced in a prototype device that had been tested in clinical conditions, or to a mixture of oxygen and ozone generated in the same device. Live cells in the biofilm were stained with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) bromide solution. The degree of reduction of viable bacteria following ozone exposure was determined. Results Ozonated water was found to be an effective bactericidal agent against biofilms after as little as 30 seconds of exposure, while the bactericidal activity of the ozone-oxygen solution was much lower. Prolongation of the duration of biofilm exposure to the gaseous disinfectant to 40 minutes led to a reduction in the viable cell count, which nevertheless remained high. Conclusions Unlike the ozone-oxygen mixture, ozonated water effectively destroys bacterial biofilms in vitro. PMID:22037737

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

    OpenAIRE

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

    2013-01-01

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

  20. Antibiotic resistance in Pseudomonas aeruginosa biofilms: towards the development of novel anti-biofilm therapies.

    Science.gov (United States)

    Taylor, Patrick K; Yeung, Amy T Y; Hancock, Robert E W

    2014-12-10

    The growth of bacteria as structured aggregates termed biofilms leads to their protection from harsh environmental conditions such as physical and chemical stresses, shearing forces, and limited nutrient availability. Because of this highly adapted ability to survive adverse environmental conditions, bacterial biofilms are recalcitrant to antibiotic therapies and immune clearance. This is particularly problematic in hospital settings where biofilms are a frequent cause of chronic and device-related infections and constitute a significant burden on the health-care system. The major therapeutic strategy against infections is the use of antibiotics, which, due to adaptive resistance, are often insufficient to clear biofilm infections. Thus, novel biofilm-specific therapies are required. Specific features of biofilm development, such as surface adherence, extracellular matrix formation, quorum sensing, and highly regulated biofilm maturation and dispersal are currently being studied as targets to be exploited in the development of novel biofilm-specific treatments. Using Pseudomonas aeruginosa for illustrative purposes, this review highlights the antibiotic resistance mechanisms of biofilms, and discusses current research into novel biofilm-specific therapies.

  1. Pseudomonas aeruginosa and Saccharomyces cerevisiae Biofilm in Flow Cells

    DEFF Research Database (Denmark)

    Weiss Nielsen, Martin; Sternberg, Claus; Molin, Søren;

    2011-01-01

    Many microbial cells have the ability to form sessile microbial communities defined as biofilms that have altered physiological and pathological properties compared to free living microorganisms. Biofilms in nature are often difficult to investigate and reside under poorly defined conditions(1). ...

  2. Biofilm Filtrates of Pseudomonas aeruginosa Strains Isolated from Cystic Fibrosis Patients Inhibit Preformed Aspergillus fumigatus Biofilms via Apoptosis.

    Science.gov (United States)

    Shirazi, Fazal; Ferreira, Jose A G; Stevens, David A; Clemons, Karl V; Kontoyiannis, Dimitrios P

    2016-01-01

    Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) colonize cystic fibrosis (CF) patient airways. Pa culture filtrates inhibit Af biofilms, and Pa non-CF, mucoid (Muc-CF) and nonmucoid CF (NMuc-CF) isolates form an ascending inhibitory hierarchy. We hypothesized this activity is mediated through apoptosis induction. One Af and three Pa (non-CF, Muc-CF, NMuc-CF) reference isolates were studied. Af biofilm was formed in 96 well plates for 16 h ± Pa biofilm filtrates. After 24 h, apoptosis was characterized by viability dye DiBAc, reactive oxygen species (ROS) generation, mitochondrial membrane depolarization, DNA fragmentation and metacaspase activity. Muc-CF and NMuc-CF filtrates inhibited and damaged Af biofilm (pbiofilms (3.7- fold) compared to treatment with filtrates from Muc-CF- (2.5- fold) or non-CF Pa (1.7- fold). Depolarization of mitochondrial potential was greater upon exposure to NMuc-CF (2.4-fold) compared to Muc-CF (1.8-fold) or non-CF (1.25-fold) (pbiofilm, compared to control, mediated by metacaspase activation. In conclusion, filtrates from CF-Pa isolates were more inhibitory against Af biofilms than from non-CF. The apoptotic effect involves mitochondrial membrane damage associated with metacaspase activation.

  3. Effect of nitrofurans and NO generators on biofilm formation by Pseudomonas aeruginosa PAO1 and Burkholderia cenocepacia 370.

    Science.gov (United States)

    Zaitseva, Julia; Granik, Vladimir; Belik, Alexandr; Koksharova, Olga; Khmel, Inessa

    2009-06-01

    Antibacterial drugs in the nitrofuran series, such as nitrofurazone, furazidin, nitrofurantoin and nifuroxazide, as well as the nitric oxide generators sodium nitroprusside and isosorbide mononitrate in concentrations that do not suppress bacterial growth, were shown to increase the capacity of pathogenic bacteria Pseudomonas aeruginosa PAO1 and Burkholderia cenocepacia 370 to form biofilms. At 25-100microg/ml, nitrofurans 2-2.5-fold enhanced biofilm formation of P. aeruginosa PAO1, and NO donors 3-6-fold. For B. cenocepacia 370, the enhancement was 2-5-fold (nitrofurans) and 4.5-fold (sodium nitroprusside), respectively. PMID:19460431

  4. Interference of Pseudomonas aeruginosa signalling and biofilm formation for infection control

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Tolker-Nielsen, Tim; Høiby, Niels;

    2010-01-01

    Pseudomonas aeruginosa is the best described bacterium with regards to quorum sensing (QS), in vitro biofilm formation and the development of antibiotic tolerance. Biofilms composed of P. aeruginosa are thought to be the underlying cause of many chronic infections, including those in wounds...... and in the lungs of patients with cystic fibrosis. In this review, we provide an overview of the molecular mechanisms involved in QS, QS-enabled virulence, biofilm formation and biofilm-enabled antibiotic tolerance. We now have substantial knowledge of the multicellular behaviour of P. aeruginosa in vitro. A major...

  5. Phenotypes selected during chronic lung infection in cystic fibrosis patients: implications for the treatment of Pseudomonas aeruginosa biofilm infections.

    Science.gov (United States)

    Ciofu, Oana; Mandsberg, Lotte F; Wang, Hengzhuang; Høiby, Niels

    2012-07-01

    During chronic lung infection of patients with cystic fibrosis, Pseudomonas aeruginosa can survive for long periods of time under the challenging selective pressure imposed by the immune system and antibiotic treatment as a result of its biofilm mode of growth and adaptive evolution mediated by genetic variation. Mucoidy, hypermutability and acquirement of mutational antibiotic resistance are important adaptive phenotypes that are selected during chronic P. aeruginosa infection. This review dicsusses the role played by these phenotypes for the tolerance of biofilms to antibiotics and show that mucoidy and hypermutability change the architecture of in vitro formed biofilms and lead to increase tolerance to antibiotics. Production of high levels of beta-lactamase impairs penetration of beta-lactam antibiotics due to inactivation of the antibiotic. In conclusion, these data underline the importance of biofilm prevention strategies by early aggressive antibiotic prophylaxis or therapy before phenotypic diversification during chronic lung infection of patients with cystic fibrosis.

  6. The novel effect of cis-2-decenoic acid on biofilm producing Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Vahid Soheili

    2016-02-01

    Full Text Available Microbial biofilms are a main cause of many chronic infections and mortalities, such as dental caries, cystic fibrosis, osteoradionecrosis, urinary tract infections and native valve endocarditis. These polymeric matrices are sessile communities with different rules from those forms via known planktonic bacteria. One of the important biofilm-producing human pathogens is Pseudomonas aeruginosa, which causes death in the majority of people who suffer from cystic fibrosis, AIDS, burns and neutropenic cancer. To find a method for controlling the growth and resistance of P. aeruginosa biofilm, this study investigated the dispersion induction of this microorganism with a diffusible signal factor (DSF, cis-2-decenoic acid (CDA, in combination with Tobramycin as a useful antibiotic. Our findings confirmed that although CDA did not act as a dispersion inducer in this experiment, it did show an antimicrobial effect and decreased the MIC of Tobramycin. These results suggested that research on the probable new effects of DSF molecules will result in advances in the control of biofilm infections.

  7. STUDY OF ULTRASOUND RADIATION INFLUENCE ON ABILITY TO FORM BIOFILMS AND FORMED BIOFILMS OF KLEBSIELLA PNEUMONIAE

    OpenAIRE

    Mozgova Yu.A.

    2013-01-01

    With aim to detect ability to form biofilms in K.pneumoniae and to study effects of low-intensity ultrasound radiation on formed biofilms and their aggregation microbiological research of material frompatients with pyoinflammatory diseases was performed. It was found that low-intensity ultrasound radiation could destroy formed biofilms of K. pneumoniae and decrease ability of this pathogen to form secondary biofilms.

  8. Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa biofilm

    DEFF Research Database (Denmark)

    Argyraki, Aikaterini; Markvart, M.; Nielsen, Anne;

    2016-01-01

    , on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose...

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

    OpenAIRE

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Katarzyna Danis-Wlodarczyk

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

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

    Directory of Open Access Journals (Sweden)

    Adela M Luján

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

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

    Science.gov (United States)

    Luján, Adela M; Maciá, María D; Yang, Liang; Molin, Søren; Oliver, Antonio; Smania, Andrea M

    2011-01-01

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

  13. Effects of Iron on DNA Release and Biofilm Development by Pseudomonas Aeruginosa

    DEFF Research Database (Denmark)

    Yang, Liang; Barken, Kim Bundvig; Skindersø, Mette Elena;

    2007-01-01

    -sensing systems has been previously presented. This paper provides evidence that DNA release in P. aeruginosa PAO1 biofilms is also under iron regulation. Experiments involving cultivation of P. aeruginosa in microtitre trays suggested that pqs expression, DNA release and biofilm formation were favoured in media...... with low iron concentrations (5 mu M FeCIA and decreased with increasing iron concentrations. Experiments involving cultivation of P. aeruginosa in a flow-chamber system suggested that a high level of iron (1100 mu M FeCl3) in the medium suppressed DNA release, structural biofilm development...

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

    OpenAIRE

    Danila Soares Caixeta; Thiago Henrique Scarpa; Danilo Florisvaldo Brugnera; Dieyckson Osvani Freire; Eduardo Alves; Luiz Ronaldo de Abreu; Roberta Hilsdorf Piccoli

    2012-01-01

    The biofilm formation of Pseudomonas aeruginosa and Pseudomonas fluorescens on AISI 304 stainless steel in the presence of reconstituted skim milk under different temperatures was conducted, and the potential of three chemical sanitizers in removing the mono-species biofilms formed was compared. Pseudomonas aeruginosa cultivated in skim milk at 28 °C presented better growth rate (10.4 log CFU.mL-1) when compared with 3.7 and 4.2 log CFU.mL-1 for P. aeruginosa and P. fluorescens cultivated at ...

  15. 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.

  16. Presence of Pseudomonas aeruginosa influences biofilm formation and surface protein expression of Staphylococcus aureus.

    Science.gov (United States)

    Kumar, Amit; Ting, Yen Peng

    2015-11-01

    Although Staphylococcus aureus and Pseudomonas aeruginosa can individually colonize and infect their hosts, the commensalistic effect of the two is more tenacious and lethal. In this study, it was shown that in co-culture with P. aeruginosa, a sub-population of S. aureus exhibited improved resistance to kanamycin by selection of small colony variant (SCV) phenotype. Additionally, biofilm formation by the two bacteria was denser in the co-culture, compared with biofilm formed in individual pure cultures. Using Atomic Force Microscope (AFM) force spectroscopy for single cells, it was demonstrated that S. aureus cultured in the presence of P. aeruginosa bound more tenaciously to substrates. Surface-shaved peptides were isolated and identified using ultra-performance liquid chromatography-quadrupole-time of flight and a homology search program spider. Results indicated that serine-rich adhesin, extracellular matrix binding protein and other putative adhesion proteins could be responsible for the enhanced attachment of S. aureus in the co-culture. Besides, several other proteins were differentially expressed, indicating the occurrence of a range of other interactions. Of particular interest was a multidrug resistant protein named ABC transporter permease which is known to expel xenobiotics out of the cells. Positive regulation of this protein could be involved in the SCV selection of S. aureus in the co-culture. PMID:25925222

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    Multiple bacterial species often coexist as communities, and compete for environmental resources. Here, we describe how an opportunistic pathogen, Pseudomonas aeruginosa, uses extracellular products to interact with the nosocomial pathogen Staphylococcus epidermidis. S. epidermidis biofilms...... and planktonic cultures were challenged with P. aeruginosa supernatant cultures overnight. Results indicated that quorum-sensing-controlled factors from P. aeruginosa supernatant inhibited S. epidermidis growth in planktonic cultures. We also found that P. aeruginosa extracellular products, mainly...... polysaccharides, disrupted established S. epidermidis biofilms. Cellulase-treated P. aeruginosa supernatant, and supernatant from pelA, ps/F and pe/Aps/BCD mutants, which are deficient in polysaccharide biosynthesis, diminished the disruption of S. epidermidis biofilms. In contrast, S. epidermidis supernatant...

  18. Sound waves effectively assist tobramycin in elimination of Pseudomonas aeruginosa biofilms in vitro.

    Science.gov (United States)

    Bandara, H M H N; Harb, A; Kolacny, D; Martins, P; Smyth, H D C

    2014-12-01

    Microbial biofilms are highly refractory to antimicrobials. The aim of this study was to investigate the use of low-frequency vibration therapy (20-20 kHz) on antibiotic-mediated Pseudomonas aeruginosa biofilm eradication. In screening studies, low-frequency vibrations were applied on model biofilm compositions to identify conditions in which surface standing waves were observed. Alginate surface tension and viscosity were also measured. The effect of vibration on P. aeruginosa biofilms was studied using a standard biofilm assay. Subminimal inhibitory concentrations (sub-MIC) of tobramycin (5 μg/ml) were added to biofilms 3 h prior, during, and immediately after vibration and quantitatively assessed by (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) reduction assay (XTT) and, qualitatively, by confocal laser scanning microscopy (CLSM). The standing waves occurred at frequencies Biofilms vibrated without sub-MIC tobramycin showed a significantly reduced metabolism compared to untreated controls (p Biofilms treated with tobramycin and vibrated simultaneously (450, 530, 610, and 650 Hz), or vibrated (450 and 650 Hz) then treated with tobramycin subsequently, or vibrated (610 Hz, 650 Hz) after 3 h of tobramycin treatment showed significantly lower metabolism compared to P. aeruginosa biofilm treated with tobramycin alone (p biofilms at sub-MIC. Thus, sound waves together with antibiotics are a promising approach in eliminating pathogenic biofilms.

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

    OpenAIRE

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

    2013-01-01

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

  20. Effect of biosurfactants on Pseudomonas aeruginosa and Staphylococcus aureus biofilms in a BioFlux channel.

    Science.gov (United States)

    Diaz De Rienzo, M A; Stevenson, P S; Marchant, R; Banat, I M

    2016-07-01

    Recent studies have indicated that biosurfactants play a role both in maintaining channels between multicellular structures in biofilms and in dispersal of cells from biofilms. A combination of caprylic acid (0.01 % v/v) together with rhamnolipids (0.04 % v/v) was applied to biofilms of Pseudomonas aeruginosa ATCC 15442, Staphylococcus aureus ATCC 9144 and a mixed culture under BioFlux flowthrough conditions and caused disruption of the biofilms. The biofilms were also treated with a combination of rhamnolipids (0.04 % v/v) and sophorolipids (0.01 %). Control treatments with PBS 1× had no apparent effect on biofilm disruption. The Gram-positive bacterium (S. aureus ATCC 9144) was more sensitive than P. aeruginosa ATCC 15442 in terms of disruption and viability as shown by Live/Dead staining. Disruption of biofilms of P. aeruginosa ATCC 15442 was minimal. Oxygen consumption by biofilms, after different treatments with biosurfactants, confirms that sophorolipid on its own is unable to kill/inhibit cells of P. aeruginosa ATCC 15442, and even when used in combination with rhamnolipids, under static conditions, no decrease in the cell viability was observed. Cells in biofilms exposed to mono-rhamnolipids (0.04 % v/v) showed behaviour typical of exposure to bacteriostatic compounds, but when exposed to di-rhamnolipids (0.04 % v/v), they displayed a pattern characteristic of bactericidal compounds. PMID:26825819

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    CF airway mucus can be infected by opportunistic microorganisms, notably Pseudomonas aeruginosa. Once organisms are established as biofilms, even the most potent antibiotics have little effect on their viability, especially during late-stage chronic infections. Better understanding of the mechani...... of the mechanisms used by P. aeruginosa to circumvent host defenses and therapeutic intervention strategies is critical for advancing novel treatment strategies....

  2. Pseudomonas aeruginosa biofilms exposed to imipenem exhibit changes in global gene expression and beta-lactamase and alginate production

    DEFF Research Database (Denmark)

    Bagge, N.; Schuster, M.; Hentzer, Morten;

    2004-01-01

    The lungs of cystic fibrosis (CF) patients are commonly colonized with Pseudomonas aeruginosa biofilms. Chronic endobronchial P. aeruginosa infections are impossible to eradicate with antibiotics, but intensive suppressive antibiotic therapy is essential to maintain the lung function of CF patien...

  3. Pyoverdine and PQS Mediated Subpopulation Interactions Involved in Pseudomonas aeruginosa Biofilm Formation

    DEFF Research Database (Denmark)

    Yang, Liang; Nilsson, Martin; Gjermansen, Morten;

    2009-01-01

    Using flow chamber-grown Pseudomonas aeruginosa biofilms as model system, we show in the present study that formation of heterogeneous biofilms may occur through mechanisms that involve complex subpopulation interactions. One example of this phenomenon is expression of the iron...

  4. Increased bactericidal activity of colistin on Pseudomonas aeruginosa biofilms in anaerobic conditions

    DEFF Research Database (Denmark)

    Mette, Kolpen; Appeldorff, Cecilie F; Brandt, Sarah;

    2016-01-01

    that production of OH⋅ may not contribute significantly to the bactericidal activity of colistin on P. aeruginosa biofilm. Thus, we investigated the effect of colistin treatment on biofilm of wildtype PAO1, a catalase deficient mutant (ΔkatA) and a colistin resistant CF isolate cultured in microtiter plates...

  5. Biofilms: an emergent form of bacterial life.

    Science.gov (United States)

    Flemming, Hans-Curt; Wingender, Jost; Szewzyk, Ulrich; Steinberg, Peter; Rice, Scott A; Kjelleberg, Staffan

    2016-08-11

    Bacterial biofilms are formed by communities that are embedded in a self-produced matrix of extracellular polymeric substances (EPS). Importantly, bacteria in biofilms exhibit a set of 'emergent properties' that differ substantially from free-living bacterial cells. In this Review, we consider the fundamental role of the biofilm matrix in establishing the emergent properties of biofilms, describing how the characteristic features of biofilms - such as social cooperation, resource capture and enhanced survival of exposure to antimicrobials - all rely on the structural and functional properties of the matrix. Finally, we highlight the value of an ecological perspective in the study of the emergent properties of biofilms, which enables an appreciation of the ecological success of biofilms as habitat formers and, more generally, as a bacterial lifestyle. PMID:27510863

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

    Directory of Open Access Journals (Sweden)

    Danila Soares Caixeta

    2012-03-01

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

  7. Pseudomonas aeruginosa biofilm-associated homoserine lactone C12 rapidly activates apoptosis in airway epithelia.

    Science.gov (United States)

    Schwarzer, Christian; Fu, Zhu; Patanwala, Maria; Hum, Lauren; Lopez-Guzman, Mirielle; Illek, Beate; Kong, Weidong; Lynch, Susan V; Machen, Terry E

    2012-05-01

    Pseudomonas aeruginosa (PA) forms biofilms in lungs of cystic fibrosis (CF) patients, a process regulated by quorum-sensing molecules including N-(3-oxododecanoyl)-l-homoserine lactone (C12). C12 (10-100 µM) rapidly triggered events commonly associated with the intrinsic apoptotic pathway in JME (CF ΔF508CFTR, nasal surface) epithelial cells: depolarization of mitochondrial (mito) membrane potential (Δψ(mito)) and release of cytochrome C (cytoC) from mitos into cytosol and activation of caspases 3/7, 8 and 9. C12 also had novel effects on the endoplasmic reticulum (release of both Ca(2+) and ER-targeted GFP and oxidized contents into the cytosol). Effects began within 5 min and were complete in 1-2 h. C12 caused similar activation of caspases and release of cytoC from mitos in Calu-3 (wtCFTR, bronchial gland) cells, showing that C12-triggered responses occurred similarly in different airway epithelial types. C12 had nearly identical effects on three key aspects of the apoptosis response (caspase 3/7, depolarization of Δψ(mito) and reduction of redox potential in the ER) in JME and CFTR-corrected JME cells (adenoviral expression), showing that CFTR was likely not an important regulator of C12-triggered apoptosis in airway epithelia. Exposure of airway cultures to biofilms from PAO1wt caused depolarization of Δψ(mito) and increases in Ca(cyto) like 10-50 µM C12. In contrast, biofilms from PAO1ΔlasI (C12 deficient) had no effect, suggesting that C12 from P. aeruginosa biofilms may contribute to accumulation of apoptotic cells that cannot be cleared from CF lungs. A model to explain the effects of C12 is proposed.

  8. Flagellin FliC Phosphorylation Affects Type 2 Protease Secretion and Biofilm Dispersal in Pseudomonas aeruginosa PAO1

    Science.gov (United States)

    Suriyanarayanan, Tanujaa; Periasamy, Saravanan; Lin, Miao-Hsia; Ishihama, Yasushi; Swarup, Sanjay

    2016-01-01

    Protein phosphorylation has a major role in controlling the life-cycle and infection stages of bacteria. Proteome-wide occurrence of S/T/Y phosphorylation has been reported for many prokaryotic systems. Previously, we reported the phosphoproteome of Pseudomonas aeruginosa and Pseudomonas putida. In this study, we show the role of S/T phosphorylation of one motility protein, FliC, in regulating multiple surface-associated phenomena of P. aeruginosa PAO1. This is the first report of occurrence of phosphorylation in the flagellar protein, flagellin FliC in its highly conserved N-terminal NDO domain across several Gram negative bacteria. This phosphorylation is likely a well-regulated phenomenon as it is growth phase dependent in planktonic cells. The absence of phosphorylation in the conserved T27 and S28 residues of FliC, interestingly, did not affect swimming motility, but affected the secretome of type 2 secretion system (T2SS) and biofilm formation of PAO1. FliC phosphomutants had increased levels and activities of type 2 secretome proteins. The secretion efficiency of T2SS machinery is associated with flagellin phosphorylation. FliC phosphomutants also formed reduced biofilms at 24 h under static conditions and had delayed biofilm dispersal under dynamic flow conditions, respectively. The levels of type 2 secretome and biofilm formation under static conditions had an inverse correlation. Hence, increase in type 2 secretome levels was accompanied by reduced biofilm formation in the FliC phosphomutants. As T2SS is involved in nutrient acquisition and biofilm dispersal during survival and spread of P. aeruginosa, we propose that FliC phosphorylation has a role in ecological adaptation of this opportunistic environmental pathogen. Altogether, we found a system of phosphorylation that affects key surface related processes such as proteases secretion by T2SS, biofilm formation and dispersal. PMID:27701473

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

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

    Objective: To investigate the effects of plant-derived phenolic compounds (i.e. caffeic acid, cinnamic acid, ferulic acid and vanillic acid) on the production of quorum sensing regulated virulence factors such as pyocyanin, biofilm formation and swarming motility of Pseudomonas aeruginosa (P. aeruginosa) isolates. Methods: Fourteen clinical P. aeruginosa isolates obtained from urine samples and P. aeruginosa PA01 strain were included in the study. The antibacterial effects of phenolic compounds were screened by well diffusion assay. Pyocyanin and biofilm ac-tivity were measured from culture supernatants and the absorbance values were measured using a spectrophotometer. Swarming plates supplemented with phenolic acids were point inoculated with P. aeruginosa strains and the ability to swarm was determined by measuring the distance of swarming from the central inoculation site. Results: Tested phenolic compounds reduced the production of pyocyanin and biofilm formation without affecting growth compared to untreated cultures. Moreover, these compounds blocked about 50% of biofilm production and swarming motility in P. aeruginosa isolates. Conclusions: We may suggest that if swarming and consecutive biofilm formation could be inhibited by the natural products as shown in our study, the bacteria could not attach to the surfaces and produce chronic infections. Antimicrobials and natural products could be combined and the dosage of antimicrobials could be reduced to overcome antimicrobial resistance and drug side effects.

  10. Dynamics of development and dispersal in sessile microbial communities: examples from Pseudomonas aeruginosa and Pseudomonas putida model biofilms

    DEFF Research Database (Denmark)

    Klausen, M.; Gjermansen, Morten; Kreft, J.-U.;

    2006-01-01

    Surface-associated microbial communities in many cases display dynamic developmental patterns. Model biofilms formed by Pseudomonas aeruginosa and Pseudomonas putida in laboratory flow-chamber setups represent examples of such behaviour. Dependent on the experimental conditions the bacteria in...... organisms do not possess comprehensive genetic programs for biofilm development. Instead the bacteria appear to have evolved a number of different mechanisms to optimize surface colonization, of which they express a subset in response to the prevailing environmental conditions. These mechanisms include the...... ability to regulate cellular adhesiveness and migration in response to micro-environmental signals including those secreted by the bacteria themselves....

  11. Beneficial biofilms in marine aquaculture? Linking points of biofilm formation mechanisms in Pseudomonas aeruginosa and Pseudoalteromonas species

    Directory of Open Access Journals (Sweden)

    Wiebke Wesseling

    2015-07-01

    Full Text Available For marine aquaculture it is suggested that a specific substrate coated with a beneficial biofilm could prevent fish egg clutches from pathogenic infestations and improve the water quality and health of adult fish while, at the same time, minimising the need for the application of antibiotics. In marine biotopes, the habitat of Pseudoalteromonas species (a strain with suggested beneficial properties, biofilms are mostly discussed in the context of fouling processes. Hence research focuses on unravelling the mechanisms of biofilm formation aiming to prevent formation or to destroy existing biofilms. Initially in this review, particular components of biofilm formation in Pseudomonas aeruginosa, a gram-negative model organism that is responsible for nosocomial infections and considered as a food spoiling agent, are described (extracellular appendages, role of matrix components, cell-cell signalling to get an advanced understanding of biofilm formation. The aim of this treatise is to seek linking points for biofilm formation of P. aeruginosa and Pseudoalteromonas sp., respectively. Furthermore, approaches are discussed for how biofilm formation can be realized to improve fish (larvae rearing by species of the genus Pseudoalteromonas.

  12. Evolution and Adaptation in Pseudomonas aeruginosa Biofilms Driven by Mismatch Repair System-Deficient Mutators

    DEFF Research Database (Denmark)

    Luján, Adela M.; Maciá, María D.; Yang, Liang;

    2011-01-01

    , which are rarely eradicated despite intensive antibiotic therapy. Current knowledge indicates that three major adaptive strategies, biofilm development, phenotypic diversification, and mutator phenotypes [driven by a defective mismatch repair system (MRS)], play important roles in P. aeruginosa chronic...... infections, but the relationship between these strategies is still poorly understood. We have used the flow-cell biofilm model system to investigate the impact of the mutS associated mutator phenotype on development, dynamics, diversification and adaptation of P. aeruginosa biofilms. Through competition...... diversification, evidenced by biofilm architecture features and by a wider range and proportion of morphotypic colony variants, respectively. Additionally, morphotypic variants generated in mutator biofilms showed increased competitiveness, providing further evidence for mutator-driven adaptive evolution...

  13. Selective labelling and eradication of antibiotic-tolerant bacterial populations in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Chua, Song Lin; Yam, Joey Kuok Hoong; Hao, Piliang;

    2016-01-01

    acids (pulsed-SILAC), to quantify newly expressed proteins in colistin-tolerant subpopulations of Pseudomonas aeruginosa biofilms (colistin is a 'last-resort' antibiotic against multidrug-resistant Gram-negative pathogens). Migration is essential for the formation of colistin-tolerant biofilm...... subpopulations, with colistin-tolerant cells using type IV pili to migrate onto the top of the colistin-killed biofilm. The colistin-tolerant cells employ quorum sensing (QS) to initiate the formation of new colistin-tolerant subpopulations, highlighting multicellular behaviour in antibiotic tolerance...... development. The macrolide erythromycin, which has been previously shown to inhibit the motility and QS of P. aeruginosa, boosts biofilm eradication by colistin. Our work provides insights on the mechanisms underlying the formation of antibiotic-tolerant populations in bacterial biofilms and indicates...

  14. Extracellular DNA Acidifies Biofilms and Induces Aminoglycoside Resistance in Pseudomonas aeruginosa.

    Science.gov (United States)

    Wilton, Mike; Charron-Mazenod, Laetitia; Moore, Richard; Lewenza, Shawn

    2015-11-09

    Biofilms consist of surface-adhered bacterial communities encased in an extracellular matrix composed of DNA, exopolysaccharides, and proteins. Extracellular DNA (eDNA) has a structural role in the formation of biofilms, can bind and shield biofilms from aminoglycosides, and induces antimicrobial peptide resistance mechanisms. Here, we provide evidence that eDNA is responsible for the acidification of Pseudomonas aeruginosa planktonic cultures and biofilms. Further, we show that acidic pH and acidification via eDNA constitute a signal that is perceived by P. aeruginosa to induce the expression of genes regulated by the PhoPQ and PmrAB two-component regulatory systems. Planktonic P. aeruginosa cultured in exogenous 0.2% DNA or under acidic conditions demonstrates a 2- to 8-fold increase in aminoglycoside resistance. This resistance phenotype requires the aminoarabinose modification of lipid A and the production of spermidine on the bacterial outer membrane, which likely reduce the entry of aminoglycosides. Interestingly, the additions of the basic amino acid L-arginine and sodium bicarbonate neutralize the pH and restore P. aeruginosa susceptibility to aminoglycosides, even in the presence of eDNA. These data illustrate that the accumulation of eDNA in biofilms and infection sites can acidify the local environment and that acidic pH promotes the P. aeruginosa antibiotic resistance phenotype.

  15. Extracellular DNA Acidifies Biofilms and Induces Aminoglycoside Resistance in Pseudomonas aeruginosa.

    Science.gov (United States)

    Wilton, Mike; Charron-Mazenod, Laetitia; Moore, Richard; Lewenza, Shawn

    2016-01-01

    Biofilms consist of surface-adhered bacterial communities encased in an extracellular matrix composed of DNA, exopolysaccharides, and proteins. Extracellular DNA (eDNA) has a structural role in the formation of biofilms, can bind and shield biofilms from aminoglycosides, and induces antimicrobial peptide resistance mechanisms. Here, we provide evidence that eDNA is responsible for the acidification of Pseudomonas aeruginosa planktonic cultures and biofilms. Further, we show that acidic pH and acidification via eDNA constitute a signal that is perceived by P. aeruginosa to induce the expression of genes regulated by the PhoPQ and PmrAB two-component regulatory systems. Planktonic P. aeruginosa cultured in exogenous 0.2% DNA or under acidic conditions demonstrates a 2- to 8-fold increase in aminoglycoside resistance. This resistance phenotype requires the aminoarabinose modification of lipid A and the production of spermidine on the bacterial outer membrane, which likely reduce the entry of aminoglycosides. Interestingly, the additions of the basic amino acid L-arginine and sodium bicarbonate neutralize the pH and restore P. aeruginosa susceptibility to aminoglycosides, even in the presence of eDNA. These data illustrate that the accumulation of eDNA in biofilms and infection sites can acidify the local environment and that acidic pH promotes the P. aeruginosa antibiotic resistance phenotype. PMID:26552982

  16. Incorporation of Farnesol Significantly Increases the Efficacy of Liposomal Ciprofloxacin against Pseudomonas aeruginosa Biofilms in Vitro.

    Science.gov (United States)

    Bandara, H M H N; Herpin, M J; Kolacny, D; Harb, A; Romanovicz, D; Smyth, H D C

    2016-08-01

    The challenge of eliminating Pseudomonas aeruginosa infections, such as in cystic fibrosis lungs, remains unchanged due to the rapid development of antibiotic resistance. Poor drug penetration into dense P. aeruginosa biofilms plays a vital role in ineffective clearance of the infection. Thus, the current antibiotic therapy against P. aeruginosa biofilms need to be revisited and alternative antibiofilm strategies need to be invented. Fungal quorum sensing molecule (QSM), farnesol, appears to have detrimental effects on P. aeruginosa. Thus, this study aimed to codeliver naturally occurring QSM farnesol, with the antibiotic ciprofloxacin as a liposomal formulation to eradicate P. aeruginosa biofilms. Four different liposomes (with ciprofloxacin and farnesol, Lcip+far; with ciprofloxacin, Lcip; with farnesol, Lfar; control, Lcon) were prepared using dehydration-rehydration method and characterized. Drug entrapment and release were evaluated by spectrometry and high performance liquid chromatography (HPLC). The efficacy of liposomes was assessed using standard biofilm assay. Liposome-treated 24 h P. aeruginosa biofilms were quantitatively assessed by XTT reduction assay and crystal violet assay, and qualitatively by confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). Ciprofloxacin release from liposomes was higher when encapsulated with farnesol (Lcip+far) compared to Lcip (3.06% vs 1.48%), whereas farnesol release was lower when encapsulated with ciprofloxacin (Lcip+far) compared to Lfar (1.81% vs 4.75%). The biofilm metabolism was significantly lower when treated with Lcip+far or Lcip compared to free ciprofloxacin (XTT, P < 0.05). When administered as Lcip+far, the ciprofloxacin concentration required to achieve similar biofilm inhibition was 125-fold or 10-fold lower compared to free ciprofloxacin or Lcip, respectively (P < 0.05). CLSM and TEM confirmed predominant biofilm disruption, greater dead cell ratio, and increased depth of

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

    Directory of Open Access Journals (Sweden)

    Saqi Mansoor

    2006-06-01

    Full Text Available Abstract Background Pseudomonas aeruginosa is a genetically complex bacterium which can adopt and switch between a free-living or biofilm lifestyle, a versatility that enables it to thrive in many different environments and contributes to its success as a human pathogen. Results Transcriptomes derived from growth states relevant to the lifestyle of P. aeruginosa were clustered using three different methods (K-means, K-means spectral and hierarchical clustering. The culture conditions used for this study were; biofilms incubated for 8, 14, 24 and 48 hrs, and planktonic culture (logarithmic and stationary phase. This cluster analysis revealed the existence and provided a clear illustration of distinct expression profiles present in the dataset. Moreover, it gave an insight into which genes are up-regulated in planktonic, developing biofilm and confluent biofilm states. In addition, this analysis confirmed the contribution of quorum sensing (QS and RpoS regulated genes to the biofilm mode of growth, and enabled the identification of a 60.69 Kbp region of the genome associated with stationary phase growth (stationary phase planktonic culture and confluent biofilms. Conclusion This is the first study to use clustering to separate a large P. aeruginosa microarray dataset consisting of transcriptomes obtained from diverse conditions relevant to its growth, into different expression profiles. These distinct expression profiles not only reveal novel aspects of P. aeruginosa gene expression but also provide a growth specific transcriptomic reference dataset for the research community.

  18. Integration of Pseudomonas aeruginosa and Legionella pneumophila in drinking water biofilms grown on domestic plumbing materials.

    Science.gov (United States)

    Moritz, Miriam M; Flemming, Hans-Curt; Wingender, Jost

    2010-06-01

    Drinking water biofilms were grown on coupons of plumbing materials, including ethylene-propylene-diene-monomer (EPDM) rubber, silane cross-linked polyethylene (PE-X b), electron-ray cross-linked PE (PE-X c) and copper under constant flow-through of cold tap water. After 14 days, the biofilms were spiked with Pseudomonas aeruginosa, Legionella pneumophila and Enterobacter nimipressuralis (10(6) cells/mL each). The test bacteria were environmental isolates from contamination events in drinking water systems. After static incubation for 24 h, water flow was resumed and continued for 4 weeks. Total cell count and heterotrophic plate count (HPC) of biofilms were monitored, and P. aeruginosa, L. pneumophila and E. nimipressuralis were quantified, using standard culture-based methods or culture-independent fluorescence in situ hybridization (FISH). After 14 days total cell counts and HPC values were highest on EPDM followed by the plastic materials and copper. P. aeruginosa and L. pneumophila became incorporated into drinking water biofilms and were capable to persist in biofilms on EPDM and PE-X materials for several weeks, while copper biofilms were colonized only by L. pneumophila in low culturable numbers. E. nimipressuralis was not detected in any of the biofilms. Application of the FISH method often yielded orders of magnitude higher levels of P. aeruginosa and L. pneumophila than culture methods. These observations indicate that drinking water biofilms grown under cold water conditions on domestic plumbing materials, especially EPDM and PE-X in the present study, can be a reservoir for P. aeruginosa and L. pneumophila that persist in these habitats mostly in a viable but non-culturable state. PMID:20556878

  19. Nitroxides as anti-biofilm compounds for the treatment of Pseudomonas aeruginosa and mixed-culture biofilms.

    Science.gov (United States)

    Alexander, Stefanie-Ann; Kyi, Caroline; Schiesser, Carl H

    2015-04-28

    A series of 23 nitroxides () was tested for biofilm modulatory activity using a crystal violet staining technique. 3-(Dodecane-1-thiyl)-4-(hydroxymethyl)-2,2,5,5-tetramethyl-1-pyrrolinoxyl () was found to significantly suppress biofilm formation and elicit dispersal events in both Pseudomonas aeruginosa and mixed-culture biofilms. Twitching and swarming motilities were enhanced by nitroxide , leaving the planktonic-specific swimming motility unaffected and suggesting that the mechanism of -mediated biofilm modulation is linked to the hyperactivation of surface-associated cell motilities. Preliminary structure-activity relationship studies identify the dodecanethiyl chain, hydroxymethyl substituent and the free radical moiety to be structural features pertinent to the anti-biofilm activity of .

  20. Glutathione-Disrupted Biofilms of Clinical Pseudomonas aeruginosa Strains Exhibit an Enhanced Antibiotic Effect and a Novel Biofilm Transcriptome.

    Science.gov (United States)

    Klare, William; Das, Theerthankar; Ibugo, Amaye; Buckle, Edwina; Manefield, Mike; Manos, Jim

    2016-08-01

    Pseudomonas aeruginosa infections result in high morbidity and mortality rates for individuals with cystic fibrosis (CF), with premature death often occurring. These infections are complicated by the formation of biofilms in the sputum. Antibiotic therapy is stymied by antibiotic resistance of the biofilm matrix, making novel antibiofilm strategies highly desirable. Within P. aeruginosa biofilms, the redox factor pyocyanin enhances biofilm integrity by intercalating with extracellular DNA. The antioxidant glutathione (GSH) reacts with pyocyanin, disrupting intercalation. This study investigated GSH disruption by assaying the physiological effects of GSH and DNase I on biofilms of clinical CF isolates grown in CF artificial sputum medium (ASMDM+). Confocal scanning laser microscopy showed that 2 mM GSH, alone or combined with DNase I, significantly disrupted immature (24-h) biofilms of Australian epidemic strain (AES) isogens AES-1R and AES-1M. GSH alone greatly disrupted mature (72-h) AES-1R biofilms, resulting in significant differential expression of 587 genes, as indicated by RNA-sequencing (RNA-seq) analysis. Upregulated systems included cyclic diguanylate and pyoverdine biosynthesis, the type VI secretion system, nitrate metabolism, and translational machinery. Biofilm disruption with GSH revealed a cellular physiology distinct from those of mature and dispersed biofilms. RNA-seq results were validated by biochemical and quantitative PCR assays. Biofilms of a range of CF isolates disrupted with GSH and DNase I were significantly more susceptible to ciprofloxacin, and increased antibiotic effectiveness was achieved by increasing the GSH concentration. This study demonstrated that GSH, alone or with DNase I, represents an effective antibiofilm treatment when combined with appropriate antibiotics, pending in vivo studies.

  1. Glutathione-Disrupted Biofilms of Clinical Pseudomonas aeruginosa Strains Exhibit an Enhanced Antibiotic Effect and a Novel Biofilm Transcriptome.

    Science.gov (United States)

    Klare, William; Das, Theerthankar; Ibugo, Amaye; Buckle, Edwina; Manefield, Mike; Manos, Jim

    2016-08-01

    Pseudomonas aeruginosa infections result in high morbidity and mortality rates for individuals with cystic fibrosis (CF), with premature death often occurring. These infections are complicated by the formation of biofilms in the sputum. Antibiotic therapy is stymied by antibiotic resistance of the biofilm matrix, making novel antibiofilm strategies highly desirable. Within P. aeruginosa biofilms, the redox factor pyocyanin enhances biofilm integrity by intercalating with extracellular DNA. The antioxidant glutathione (GSH) reacts with pyocyanin, disrupting intercalation. This study investigated GSH disruption by assaying the physiological effects of GSH and DNase I on biofilms of clinical CF isolates grown in CF artificial sputum medium (ASMDM+). Confocal scanning laser microscopy showed that 2 mM GSH, alone or combined with DNase I, significantly disrupted immature (24-h) biofilms of Australian epidemic strain (AES) isogens AES-1R and AES-1M. GSH alone greatly disrupted mature (72-h) AES-1R biofilms, resulting in significant differential expression of 587 genes, as indicated by RNA-sequencing (RNA-seq) analysis. Upregulated systems included cyclic diguanylate and pyoverdine biosynthesis, the type VI secretion system, nitrate metabolism, and translational machinery. Biofilm disruption with GSH revealed a cellular physiology distinct from those of mature and dispersed biofilms. RNA-seq results were validated by biochemical and quantitative PCR assays. Biofilms of a range of CF isolates disrupted with GSH and DNase I were significantly more susceptible to ciprofloxacin, and increased antibiotic effectiveness was achieved by increasing the GSH concentration. This study demonstrated that GSH, alone or with DNase I, represents an effective antibiofilm treatment when combined with appropriate antibiotics, pending in vivo studies. PMID:27161630

  2. Influence of clove oil on certain quorum-sensing-regulated functions and biofilm of Pseudomonas aeruginosa and Aeromonas hydrophila

    Indian Academy of Sciences (India)

    Fohad Mabood Husain; Iqbal Ahmad; Mohammad Asif; Qudsia Tahseen

    2013-12-01

    Quorum sensing (QS) plays an important role in virulence, biofilm formation and survival of many pathogenic bacteria including Pseudomonas aeruginosa. This signalling pathway is considered as novel and promising target for anti-infective agents. In the present investigation, effect of the Sub-MICs of clove oil on QS regulated virulence factors and biofilm formation was evaluated against P. aeruginosa PAO1 and Aeromonas hydrophila WAF-38 strain. Sub-inhibitory concentrations of the clove oil demonstrated statistically significant reduction of las- and rhl-regulated virulence factors such as LasB, total protease, chitinase and pyocyanin production, swimming motility and exopolysaccharide production. The biofilm forming capability of PAO1 and A. hydrophila WAF-38 was also reduced in a concentration-dependent manner at all tested sub-MIC values. Further, the PAO1-preinfected Caenorhabditis elegans displayed an enhanced survival when treated with 1.6% v/v of clove oil. The above findings highlight the promising anti-QS-dependent therapeutic function of clove oil against P. aeruginosa.

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

    OpenAIRE

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

    2006-01-01

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

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

    OpenAIRE

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

    2013-01-01

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

  5. Extracellular DNA chelates cations and induces antibiotic resistance in Pseudomonas aeruginosa biofilms.

    Directory of Open Access Journals (Sweden)

    Heidi Mulcahy

    2008-11-01

    Full Text Available Biofilms are surface-adhered bacterial communities encased in an extracellular matrix composed of DNA, bacterial polysaccharides and proteins, which are up to 1000-fold more antibiotic resistant than planktonic cultures. To date, extracellular DNA has been shown to function as a structural support to maintain Pseudomonas aeruginosa biofilm architecture. Here we show that DNA is a multifaceted component of P. aeruginosa biofilms. At physiologically relevant concentrations, extracellular DNA has antimicrobial activity, causing cell lysis by chelating cations that stabilize lipopolysaccharide (LPS and the outer membrane (OM. DNA-mediated killing occurred within minutes, as a result of perturbation of both the outer and inner membrane (IM and the release of cytoplasmic contents, including genomic DNA. Sub-inhibitory concentrations of DNA created a cation-limited environment that resulted in induction of the PhoPQ- and PmrAB-regulated cationic antimicrobial peptide resistance operon PA3552-PA3559 in P. aeruginosa. Furthermore, DNA-induced expression of this operon resulted in up to 2560-fold increased resistance to cationic antimicrobial peptides and 640-fold increased resistance to aminoglycosides, but had no effect on beta-lactam and fluoroquinolone resistance. Thus, the presence of extracellular DNA in the biofilm matrix contributes to cation gradients, genomic DNA release and inducible antibiotic resistance. DNA-rich environments, including biofilms and other infection sites like the CF lung, are likely the in vivo environments where extracellular pathogens such as P. aeruginosa encounter cation limitation.

  6. In vitro production of biofilm in a flow cell system in a strain of Pseudomonas aeruginosa and Staphylococcus aureus and determination of efficiency of ciprofloxacin against them

    Directory of Open Access Journals (Sweden)

    Soham Gupta

    2011-01-01

    Full Text Available Background: Microorganisms develop biofilm on various medical devices. The process is particularly relevant in public health since biofilm associated organisms are much more resistant to antibiotics and have a potential to cause infections in patients with indwelling medical devices. Materials and Methods: To determine the efficiency of an antibiotic against the biofilm it is inappropriate to use traditional technique of determining Minimum Inhibitory Concentration (MIC on the free floating laboratory phenotype. Thus we have induced formation of biofilm in two strains (Pseudomonas aeruginosa and Staphylococcus aureus, which showed heavy growth of biofilm in screening by Tube method in a flow cell system and determined their antibiotic susceptibility against ciprofloxacin by agar dilution method in the range (0.25 mg/ml to 8 mg/ml. The MIC value of ciprofloxacin for the biofilm produced organism was compared with its free form and a standard strain as control on the same plates. Observations: Both the biofilm produced strains showed a higher resistance (MIC > 8 mg/ml than its free form, which were 2 μg/ml for Pseudomonas aeruginosa and 4 mg/ml for Staphylococcus aureus. Thus biofilm can pose a threat in the patient treatment.

  7. 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...... and biofilms were produced during a 3 day period. Tubes in lengths of 10 ( Teflon, silicone) and 20 cm ( Teflon) were contaminated. Tubes for control and for UVC treatment were contaminated in parallel. Biofilms were sampled from the total inner surface of the tubes. Colony counts on the control samples were...

  8. Motility of Pseudomonas aeruginosa contributes to SOS-inducible biofilm formation.

    Science.gov (United States)

    Chellappa, Shakinah T; Maredia, Reshma; Phipps, Kara; Haskins, William E; Weitao, Tao

    2013-12-01

    DNA-damaging antibiotics such as ciprofloxacin induce biofilm formation and the SOS response through autocleavage of SOS-repressor LexA in Pseudomonas aeruginosa. However, the biofilm-SOS connection remains poorly understood. It was investigated with 96-well and lipid biofilm assays. The effects of ciprofloxacin were examined on biofilm stimulation of the SOS mutant and wild-type strains. The stimulation observed in the wild-type in which SOS was induced was reduced in the mutant in which LexA was made non-cleavable (LexAN) and thus SOS non-inducible. Therefore, the stimulation appeared to involve SOS. The possible mechanisms of inducible biofilm formation were explored by subproteomic analysis of outer membrane fractions extracted from biofilms. The data predicted an inhibitory role of LexA in flagellum function. This premise was tested first by functional and morphological analyses of flagellum-based motility. The flagellum swimming motility decreased in the LexAN strain treated with ciprofloxacin. Second, the motility-biofilm assay was performed, which tested cell migration and biofilm formation. The results showed that wild-type biofilm increased significantly over the LexAN. These results suggest that LexA repression of motility, which is the initial event in biofilm development, contributes to repression of SOS-inducible biofilm formation.

  9. Metabolomics-Based Screening of Biofilm-Inhibitory Compounds against Pseudomonas aeruginosa from Burdock Leaf

    OpenAIRE

    Zaixiang Lou; Yuxia Tang; Xinyi Song; Hongxin Wang

    2015-01-01

    Screening of anti-biofilm compounds from the burdock leaf based on metabolomics is reported here. The crystal violet assay indicated 34% ethanol elution fraction of burdock leaf could completely inhibit biofilm formation of Pseudomonas aeruginosa at 1 mg·mL−1. Then, the chemical composition of burdock leaf fraction was analyzed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and 11 active compounds (chlorogenic acid, caffeic acid, p-coumaric acid, quercetin, ursolic aci...

  10. Electrolytic Generation of Oxygen Partially Explains Electrical Enhancement of Tobramycin Efficacy against Pseudomonas aeruginosa Biofilm

    OpenAIRE

    Stewart, Philip S.; Wattanakaroon, Wanida; Goodrum, Lu; Fortun, Susana M.; McLeod, Bruce R.

    1999-01-01

    The role of electrolysis products, including protons, hydroxyl ions, reactive oxygen intermediates, oxygen, hydrogen, and heat, in mediating electrical enhancement of killing of Pseudomonas aeruginosa biofilms by tobramycin (the bioelectric effect) was investigated. The log reduction in biofilm viable cell numbers compared to the numbers for the untreated positive control effected by antibiotic increased from 2.88 in the absence of electric current to 5.58 in the presence of electric current....

  11. Ginger Extract Inhibits Biofilm Formation by Pseudomonas aeruginosa PA14

    OpenAIRE

    Han-Shin Kim; Hee-Deung Park

    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 ...

  12. Plasma-mediated inactivation of Pseudomonas aeruginosa biofilms grown on borosilicate surfaces under continuous culture system.

    Science.gov (United States)

    Vandervoort, Kurt G; Brelles-Mariño, Graciela

    2014-01-01

    Biofilms are microbial communities attached to a surface and embedded in a matrix composed of exopolysaccharides and excreted nucleic acids. Bacterial biofilms are responsible for undesirable effects such as disease, prostheses colonization, biofouling, equipment damage, and pipe plugging. Biofilms are also more resilient than free-living cells to regular sterilization methods and therefore it is indispensable to develop better ways to control and remove them. The use of gas discharge plasmas is a good alternative since plasmas contain a mixture of reactive agents well-known for their decontamination potential against free microorganisms. We have previously reported that Pseudomonas aeruginosa biofilms were inactivated after a 1-min plasma exposure. We determined that the adhesiveness and the thickness of Pseudomonas biofilms grown on borosilicate were reduced. We also reported sequential morphological changes and loss of viability upon plasma treatment. However, the studies were carried out in batch cultures. The use of a continuous culture results in a more homogenous environment ensuring reproducible biofilm growth. The aim of this work was to study plasma-mediated inactivation of P. aeruginosa biofilms grown on borosilicate in a continuous culture system. In this paper we show that biofilms grown on glass under continuous culture can be inactivated by using gas discharge plasma. Both biofilm architecture and cell culturability are impacted by the plasma treatment. The inactivation kinetics is similar to previously described ones and cells go through sequential changes ranging from minimal modification without loss of viability at short plasma exposure times, to major structure and viability loss at longer exposure times. We report that changes in biofilm structure leading to the loss of culturability and viability are related to a decrease of the biofilm matrix adhesiveness. To our knowledge, there has been no attempt to evaluate the inactivation

  13. Plasma-mediated inactivation of Pseudomonas aeruginosa biofilms grown on borosilicate surfaces under continuous culture system.

    Directory of Open Access Journals (Sweden)

    Kurt G Vandervoort

    Full Text Available Biofilms are microbial communities attached to a surface and embedded in a matrix composed of exopolysaccharides and excreted nucleic acids. Bacterial biofilms are responsible for undesirable effects such as disease, prostheses colonization, biofouling, equipment damage, and pipe plugging. Biofilms are also more resilient than free-living cells to regular sterilization methods and therefore it is indispensable to develop better ways to control and remove them. The use of gas discharge plasmas is a good alternative since plasmas contain a mixture of reactive agents well-known for their decontamination potential against free microorganisms. We have previously reported that Pseudomonas aeruginosa biofilms were inactivated after a 1-min plasma exposure. We determined that the adhesiveness and the thickness of Pseudomonas biofilms grown on borosilicate were reduced. We also reported sequential morphological changes and loss of viability upon plasma treatment. However, the studies were carried out in batch cultures. The use of a continuous culture results in a more homogenous environment ensuring reproducible biofilm growth. The aim of this work was to study plasma-mediated inactivation of P. aeruginosa biofilms grown on borosilicate in a continuous culture system. In this paper we show that biofilms grown on glass under continuous culture can be inactivated by using gas discharge plasma. Both biofilm architecture and cell culturability are impacted by the plasma treatment. The inactivation kinetics is similar to previously described ones and cells go through sequential changes ranging from minimal modification without loss of viability at short plasma exposure times, to major structure and viability loss at longer exposure times. We report that changes in biofilm structure leading to the loss of culturability and viability are related to a decrease of the biofilm matrix adhesiveness. To our knowledge, there has been no attempt to evaluate the

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

    Science.gov (United States)

    Mai-Prochnow, Anne; Bradbury, Mark; Ostrikov, Kostya; Murphy, Anthony B

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Anne Mai-Prochnow

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

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    should allow opportunistic pathogenic bacteria to utilize their eukaryote-targeting arsenal to attack and exploit protozoan host cells. Studying cocultures of the environmental pathogen Pseudomonas aeruginosa and the amoeba Acanthamoeba castellanii, we found that P. aeruginosa rapidly colonized...... and killed biofilm-associated amoebae by a quorum-sensing independent mechanism. Analysis of the amoeba-induced transcriptome indicated the involvement of the P. aeruginosa type III secretion system (T3SS) in this interaction. A comparison of mutants with specific defects in the T3SS demonstrated the use...

  17. Pseudomonas aeruginosa biofilm aggravates skin inflammatory response in BALB/c mice in a novel chronic wound model

    DEFF Research Database (Denmark)

    Trøstrup, Hannah; Thomsen, Kim; Christophersen, Lars J;

    2013-01-01

    Chronic wounds are presumed to persist in the inflammatory state, preventing healing. Emerging evidence indicates a clinical impact of bacterial biofilms in soft tissues, including Pseudomonas aeruginosa (PA) biofilms. To further investigate this, we developed a chronic PA biofilm wound infection...

  18. Decreased Pseudomonas aeruginosa biofilm formation on nanomodified endotracheal tubes: a dynamic lung model.

    Science.gov (United States)

    Machado, Mary C; Webster, Thomas J

    2016-01-01

    Ventilator-associated pneumonia (VAP) is a serious complication of mechanical ventilation that has been shown to be associated with increased mortality rates and medical costs in the pediatric intensive care unit. Currently, there is no cost-effective solution to the problems posed by VAP. Endotracheal tubes (ETTs) that are resistant to bacterial colonization and that inhibit biofilm formation could provide a novel solution to the problems posed by VAP. The objective of this in vitro study was to evaluate differences in the growth of Pseudomonas aeruginosa on unmodified polyvinyl chloride (PVC) ETTs and on ETTs etched with a fungal lipase, Rhizopus arrhizus, to create nanoscale surface features. These differences were evaluated using an in vitro model of the pediatric airway to simulate a ventilated patient in the pediatric intensive care unit. Each experiment was run for 24 hours and was supported by computational models of the ETT. Dynamic conditions within the ETT had an impact on the location of bacterial growth within the tube. These conditions also quantitatively affected bacterial growth especially within the areas of tube curvature. Most importantly, experiments in the in vitro model revealed a 2.7 log reduction in the number (colony forming units/mL) of P. aeruginosa on the nanoroughened ETTs compared to the untreated PVC ETTs after 24 hours. This reduction in total colony forming units/mL along the x-axis of the tube was similar to previous studies completed for Staphylococcus aureus. Thus, this dynamic study showed that lipase etching can create surface features of nanoscale roughness on PVC ETTs that decrease bacterial attachment of P. aeruginosa without the use of antibiotics and may provide clinicians with an effective and inexpensive tool to combat VAP. PMID:27563242

  19. Decreased Pseudomonas aeruginosa biofilm formation on nanomodified endotracheal tubes: a dynamic lung model

    Science.gov (United States)

    Machado, Mary C; Webster, Thomas J

    2016-01-01

    Ventilator-associated pneumonia (VAP) is a serious complication of mechanical ventilation that has been shown to be associated with increased mortality rates and medical costs in the pediatric intensive care unit. Currently, there is no cost-effective solution to the problems posed by VAP. Endotracheal tubes (ETTs) that are resistant to bacterial colonization and that inhibit biofilm formation could provide a novel solution to the problems posed by VAP. The objective of this in vitro study was to evaluate differences in the growth of Pseudomonas aeruginosa on unmodified polyvinyl chloride (PVC) ETTs and on ETTs etched with a fungal lipase, Rhizopus arrhizus, to create nanoscale surface features. These differences were evaluated using an in vitro model of the pediatric airway to simulate a ventilated patient in the pediatric intensive care unit. Each experiment was run for 24 hours and was supported by computational models of the ETT. Dynamic conditions within the ETT had an impact on the location of bacterial growth within the tube. These conditions also quantitatively affected bacterial growth especially within the areas of tube curvature. Most importantly, experiments in the in vitro model revealed a 2.7 log reduction in the number (colony forming units/mL) of P. aeruginosa on the nanoroughened ETTs compared to the untreated PVC ETTs after 24 hours. This reduction in total colony forming units/mL along the x-axis of the tube was similar to previous studies completed for Staphylococcus aureus. Thus, this dynamic study showed that lipase etching can create surface features of nanoscale roughness on PVC ETTs that decrease bacterial attachment of P. aeruginosa without the use of antibiotics and may provide clinicians with an effective and inexpensive tool to combat VAP. PMID:27563242

  20. Inoculation density and nutrient level determine the formation of mushroom-shaped structures in Pseudomonas aeruginosa biofilms

    Science.gov (United States)

    Ghanbari, Azadeh; Dehghany, Jaber; Schwebs, Timo; Müsken, Mathias; Häussler, Susanne; Meyer-Hermann, Michael

    2016-01-01

    Pseudomonas aeruginosa often colonises immunocompromised patients and the lungs of cystic fibrosis patients. It exhibits resistance to many antibiotics by forming biofilms, which makes it hard to eliminate. P. aeruginosa biofilms form mushroom-shaped structures under certain circumstances. Bacterial motility and the environment affect the eventual mushroom morphology. This study provides an agent-based model for the bacterial dynamics and interactions influencing bacterial biofilm shape. Cell motility in the model relies on recently published experimental data. Our simulations show colony formation by immotile cells. Motile cells escape from a single colony by nutrient chemotaxis and hence no mushroom shape develops. A high number density of non-motile colonies leads to migration of motile cells onto the top of the colonies and formation of mushroom-shaped structures. This model proposes that the formation of mushroom-shaped structures can be predicted by parameters at the time of bacteria inoculation. Depending on nutrient levels and the initial number density of stalks, mushroom-shaped structures only form in a restricted regime. This opens the possibility of early manipulation of spatial pattern formation in bacterial colonies, using environmental factors. PMID:27611778

  1. Inhibition of Pseudomonas aeruginosa biofilm formation by 2,2’-bipyridyl, lipoic, kojic and picolinic acids

    Directory of Open Access Journals (Sweden)

    Kübra Çevik

    2015-08-01

    Full Text Available Objective(s:The inhibitory effects of iron chelators, and FeCl3 chelation on biofilm formation and swarming motility were investigated against an opportunistic human pathogen Pseudomonas aeruginosa. Materials and Methods:The inhibitory activity of 2,2’-bipyridyl, lipoic acid, kojic acid and picolinic acidonbiofilm formation of P. aeruginosa strain PAO1 and three clinical isolates (P. aeruginosa  PAK01,P. aeruginosa PAK02 and P. aeruginosa PAK03 were investigated, based on crystal violet assay, and swarming motility test. Results:The kojic, lipoic and picolinic acid inhibited biofilm formation by 5-33% in all tested P. aeruginosa isolates. When chelated iron was added, biofilm inhibition rates were determined to be 39-57%. Among the tested chelators against P. aeruginosa, lipoic acid (84% and kojic acid (68% presented the highest inhibition of swarming motility. This is the first study to report the inhibitory effect of lipoic acid on biofilm formation and swarming motility of P. aeruginosa. Conclusion: It is considered that lipoic and picolinic acids can serve as alternatives for the treatment of the P. aeruginosa infections by inhibiting biofilm formation.

  2. Reinforcement of the bactericidal effect of ciprofloxacin on Pseudomonas aeruginosa biofilm by hyperbaric oxygen treatment

    DEFF Research Database (Denmark)

    Kolpen, Mette; Mousavi, Nabi; Sams, Thomas;

    2016-01-01

    Chronic Pseudomonas aeruginosa lung infection is the most severe complication in cystic fibrosis patients. It is characterised by antibiotic-tolerant biofilms in the endobronchial mucus with zones of oxygen (O2) depletion mainly due to polymorphonuclear leucocyte activity. Whilst the exact mechan...

  3. 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, but...

  4. 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...

  5. Microbiologically Influenced Corrosion of 2707 Hyper-Duplex Stainless Steel by Marine Pseudomonas aeruginosa Biofilm

    Science.gov (United States)

    Li, Huabing; Zhou, Enze; Zhang, Dawei; Xu, Dake; Xia, Jin; Yang, Chunguang; Feng, Hao; Jiang, Zhouhua; Li, Xiaogang; Gu, Tingyue; Yang, Ke

    2016-02-01

    Microbiologically Influenced Corrosion (MIC) is a serious problem in many industries because it causes huge economic losses. Due to its excellent resistance to chemical corrosion, 2707 hyper duplex stainless steel (2707 HDSS) has been used in the marine environment. However, its resistance to MIC was not experimentally proven. In this study, the MIC behavior of 2707 HDSS caused by the marine aerobe Pseudomonas aeruginosa was investigated. Electrochemical analyses demonstrated a positive shift in the corrosion potential and an increase in the corrosion current density in the presence of the P. aeruginosa biofilm in the 2216E medium. X-ray photoelectron spectroscopy (XPS) analysis results showed a decrease in Cr content on the coupon surface beneath the biofilm. The pit imaging analysis showed that the P. aeruginosa biofilm caused a largest pit depth of 0.69 μm in 14 days of incubation. Although this was quite small, it indicated that 2707 HDSS was not completely immune to MIC by the P. aeruginosa biofilm.

  6. Metabolomics-Based Screening of Biofilm-Inhibitory Compounds against Pseudomonas aeruginosa from Burdock Leaf

    Directory of Open Access Journals (Sweden)

    Zaixiang Lou

    2015-09-01

    Full Text Available Screening of anti-biofilm compounds from the burdock leaf based on metabolomics is reported here. The crystal violet assay indicated 34% ethanol elution fraction of burdock leaf could completely inhibit biofilm formation of Pseudomonas aeruginosa at 1 mg·mL−1. Then, the chemical composition of burdock leaf fraction was analyzed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS and 11 active compounds (chlorogenic acid, caffeic acid, p-coumaric acid, quercetin, ursolic acid, rutin, cynarin, luteolin, crocin, benzoic acid, and Tenacissoside I were identified. Lastly, UPLC-MS analysis was employed to obtain the metabolic fingerprints of burdock leaf fractions before and after inhibiting the biofilm of Pseudomonas aeruginosa. The metabolic fingerprints were transformed to data, analyzed with PLS-DA (partial least squares discriminant analysis and the peaks whose area was significantly changed were found out. Thus, 81 compounds were screened as potential anti-biofilm ingredients. Among them, rutin, ursolic acid, caffeic acid, p-coumaric acid and quercetin were identified and confirmed as the main anti-biofilm compounds in burdock leaf. The study provided basic anti-biofilm profile data for the compounds in burdock leaf, as well as provided a convenient method for fast screening of anti-biofilm compounds from natural plants.

  7. Metabolomics-Based Screening of Biofilm-Inhibitory Compounds against Pseudomonas aeruginosa from Burdock Leaf.

    Science.gov (United States)

    Lou, Zaixiang; Tang, Yuxia; Song, Xinyi; Wang, Hongxin

    2015-01-01

    Screening of anti-biofilm compounds from the burdock leaf based on metabolomics is reported here. The crystal violet assay indicated 34% ethanol elution fraction of burdock leaf could completely inhibit biofilm formation of Pseudomonas aeruginosa at 1 mg·mL(-1). Then, the chemical composition of burdock leaf fraction was analyzed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and 11 active compounds (chlorogenic acid, caffeic acid, p-coumaric acid, quercetin, ursolic acid, rutin, cynarin, luteolin, crocin, benzoic acid, and Tenacissoside I) were identified. Lastly, UPLC-MS analysis was employed to obtain the metabolic fingerprints of burdock leaf fractions before and after inhibiting the biofilm of Pseudomonas aeruginosa. The metabolic fingerprints were transformed to data, analyzed with PLS-DA (partial least squares discriminant analysis) and the peaks whose area was significantly changed were found out. Thus, 81 compounds were screened as potential anti-biofilm ingredients. Among them, rutin, ursolic acid, caffeic acid, p-coumaric acid and quercetin were identified and confirmed as the main anti-biofilm compounds in burdock leaf. The study provided basic anti-biofilm profile data for the compounds in burdock leaf, as well as provided a convenient method for fast screening of anti-biofilm compounds from natural plants. PMID:26370951

  8. Optimal dosing regimen of nitric oxide donor compounds for the reduction of Pseudomonas aeruginosa biofilm and isolates from wastewater membranes.

    Science.gov (United States)

    Barnes, Robert J; Bandi, Ratnaharika R; Wong, Wee Seng; Barraud, Nicolas; McDougald, Diane; Fane, Anthony; Kjelleberg, Staffan; Rice, Scott A

    2013-01-01

    Membrane fouling by bacterial biofilms remains a key challenge for membrane-based water purification systems. Here, the optimal biofilm dispersal potential of three nitric oxide (NO) donor compounds, viz. sodium nitroprusside, 6-(2-hydroxy-1-methyl-2-nitrosohydrazino)-N-methyl-1-hexanamine (MAHMA NONOate) and 1-(hydroxy-NNO-azoxy)-L-proline, disodium salt, was investigated using Pseudomonas aeruginosa PAO1 as a model organism. Dispersal was quantitatively assessed by confocal microscopy [bacterial cells and the components of the extracellular polymeric substances (EPS) (polysaccharides and extracellular DNA)] and colony-forming unit counts. The three NO donor compounds had different optimal exposure times and concentrations, with MAHMA NONOate being the optimal NO donor compound. Biofilm dispersal correlated with a reduction in both bacterial cells and EPS. MAHMA NONOate also reduced single species biofilms formed by bacteria isolated from industrial membrane bioreactor and reverse osmosis membranes, as well as in isolates combined to generate mixed species biofilms. The data present strong evidence for the application of these NO donor compounds for prevention of biofouling in an industrial setting.

  9. 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...... 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......). 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...

  10. Glucose starvation-induced dispersal of Pseudomonas aeruginosa biofilms is cAMP and energy dependent.

    Directory of Open Access Journals (Sweden)

    Tran T Huynh

    Full Text Available Carbon starvation has been shown to induce a massive dispersal event in biofilms of the opportunistic pathogen Pseudomonas aeruginosa; however, the molecular pathways controlling this dispersal response remain unknown. We quantified changes in the proteome of P. aeruginosa PAO1 biofilm and planktonic cells during glucose starvation by differential peptide-fingerprint mass-spectrometry (iTRAQ. In addition, we monitored dispersal photometrically, as a decrease in turbidity/opacity of biofilms pre-grown and starved in continuous flow-cells, in order to evaluate treatments (e.g. inhibitors CCCP, arsenate, chloramphenicol, L-serine hydroxamate and key mutants altered in biofilm development and dispersal (e.g. nirS, vfr, bdlA, rpoS, lasRrhlR, Pf4-bacteriophage and cyaA. In wild-type biofilms, dispersal started within five minutes of glucose starvation, was maximal after 2 h, and up to 60% of the original biomass had dispersed after 24 h of starvation. The changes in protein synthesis were generally not more than two fold and indicated that more than 100 proteins belonging to various classes, including carbon and energy metabolism, stress adaptation, and motility, were differentially expressed. For the different treatments, only the proton-ionophore CCCP or arsenate, an inhibitor of ATP synthesis, prevented dispersal of the biofilms. For the different mutants tested, only cyaA, the synthase of the intracellular second messenger cAMP, failed to disperse; complementation of the cyaA mutation restored the wild-type phenotype. Hence, the pathway for carbon starvation-induced biofilm dispersal in P. aeruginosa PAO1 involves ATP production via direct ATP synthesis and proton-motive force dependent step(s and is mediated through cAMP, which is likely to control the activity of proteins involved in remodeling biofilm cells in preparation for planktonic survival.

  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. Control of Candida albicans metabolism and biofilm formation by Pseudomonas aeruginosa phenazines.

    Science.gov (United States)

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

    2013-01-01

    Candida albicans has developmental programs that govern transitions between yeast and filamentous morphologies and between unattached and biofilm lifestyles. Here, we report that filamentation, intercellular adherence, and biofilm development were inhibited during interactions between Candida albicans and Pseudomonas aeruginosa through the action of P. aeruginosa-produced phenazines. While phenazines are toxic to C. albicans at millimolar concentrations, we found that lower concentrations of any of three different phenazines (pyocyanin, phenazine methosulfate, and phenazine-1-carboxylate) allowed growth but affected the development of C. albicans wrinkled colony biofilms and inhibited the fungal yeast-to-filament transition. Phenazines impaired C. albicans growth on nonfermentable carbon sources and led to increased production of fermentation products (ethanol, glycerol, and acetate) in glucose-containing medium, leading us to propose that phenazines specifically inhibited respiration. Methylene blue, another inhibitor of respiration, also prevented the formation of structured colony biofilms. The inhibition of filamentation and colony wrinkling was not solely due to lowered extracellular pH induced by fermentation. Compared to smooth, unstructured colonies, wrinkled colony biofilms had higher oxygen concentrations within the colony, and wrinkled regions of these colonies had higher levels of respiration. Together, our data suggest that the structure of the fungal biofilm promotes access to oxygen and enhances respiratory metabolism and that the perturbation of respiration by bacterial molecules such as phenazines or compounds with similar activities disrupts these pathways. These findings may suggest new ways to limit fungal biofilms in the context of disease. IMPORTANCE Many of the infections caused by Candida albicans, a major human opportunistic fungal pathogen, involve both morphological transitions and the formation of surface-associated biofilms. Through the

  13. 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.

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

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    Catherine R Stewart

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

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

    Science.gov (United States)

    Holguín, Angela V.; Rangel, Guillermo; Clavijo, Viviana; Prada, Catalina; Mantilla, Marcela; Gomez, María Catalina; Kutter, Elizabeth; Taylor, Corinda; Fineran, Peter C.; Barrios, Andrés Fernando González; Vives, Martha J.

    2015-01-01

    Pseudomonas aeruginosa is one of the Multi-Drug-Resistant organisms most frequently isolated worldwide and, because of a shortage of new antibiotics, bacteriophages are considered an alternative for its treatment. Previously, P. aeruginosa phages were isolated and best candidates were chosen based on their ability to form clear plaques and their host range. This work aimed to characterize one of those phages, ΦPan70, preliminarily identified as a good candidate for phage-therapy. We performed infection curves, biofilm removal assays, transmission-electron-microscopy, pulsed-field-gel-electrophoresis, and studied the in vivo ΦPan70 biological activity in the burned mouse model. ΦPan70 was classified as a member of the Myoviridae family and, in both planktonic cells and biofilms, was responsible for a significant reduction in the bacterial population. The burned mouse model showed an animal survival between 80% and 100%, significantly different from the control animals (0%). However, analysis of the ΦPan70 genome revealed that it was 64% identical to F10, a temperate P. aeruginosa phage. Gene annotation indicated ΦPan70 as a new, but possible temperate phage, therefore not ideal for phage-therapy. Based on this, we recommend genome sequence analysis as an early step to select candidate phages for potential application in phage-therapy, before entering into a more intensive characterization. PMID:26274971

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

    Directory of Open Access Journals (Sweden)

    Angela V. Holguín

    2015-08-01

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

  17. The LapG protein plays a role in Pseudomonas aeruginosa biofilm formation by controlling the presence of the CdrA adhesin on the cell surface

    DEFF Research Database (Denmark)

    Rybtke, Morten; Berthelsen, Jens; Yang, Liang;

    2015-01-01

    Pseudomonas aeruginosa is a clinically relevant species involved in biofilm-based chronic infections. We provide evidence that the P. aeruginosa LapG protein functions as a periplasmic protease that can cleave the protein adhesin CdrA off the cell surface, and thereby plays a role in biofilm...... formation and biofilm dispersal. The P. aeruginosa LapG protein is shown to be a functional homolog of the Pseudomonas putida LapG protein which has previously been shown to function as a periplasmic protease that targets the surface adhesin LapA. Transposon mutagenesis and characterization of defined...... knockout mutants provided evidence that the CdrA adhesin is a target of LapG in P. aeruginosa. A wspF lapG double mutant was hyper-aggregating and hyper biofilm forming, whereas a wspF lapG cdrA triple mutant lost these phenotypes. In addition, western blot detection of CdrA in culture supernatants...

  18. Pseudomonas aeruginosa lipopolysaccharide inhibits Candida albicans hyphae formation and alters gene expression during biofilm development.

    Science.gov (United States)

    Bandara, H M H N; K Cheung, B P; Watt, R M; Jin, L J; Samaranayake, L P

    2013-02-01

    Elucidation of bacterial and fungal interactions in multispecies biofilms will have major impacts on understanding the pathophysiology of infections. The objectives of this study were to (i) evaluate the effect of Pseudomonas aeruginosa lipopolysaccharide (LPS) on Candida albicans hyphal development and transcriptional regulation, (ii) investigate protein expression during biofilm formation, and (iii) propose likely molecular mechanisms for these interactions. The effect of LPS on C. albicans biofilms was assessed by XTT-reduction and growth curve assays, light microscopy, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Changes in candidal hypha-specific genes (HSGs) and transcription factor EFG1 expression were assessed by real-time polymerase chain reaction and two-dimensional gel electrophoresis, respectively. Proteome changes were examined by mass spectrometry. Both metabolic activities and growth rates of LPS-treated C. albicans biofilms were significantly lower (P yeasts in test biofilms compared with the controls. SEM and CLSM further confirmed these data. Significantly upregulated HSGs (at 48 h) and EFG1 (up to 48 h) were noted in the test biofilms (P < 0.05) but cAMP levels remained unaffected. Proteomic analysis showed suppression of candidal septicolysin-like protein, potential reductase-flavodoxin fragment, serine hydroxymethyltransferase, hypothetical proteins Cao19.10301(ATP7), CaO19.4716(GDH1), CaO19.11135(PGK1), CaO19.9877(HNT1) by P. aeruginosa LPS. Our data imply that bacterial LPS inhibit C. albicans biofilm formation and hyphal development. The P. aeruginosa LPS likely target glycolysis-associated mechanisms during candidal filamentation. PMID:23194472

  19. Magnesium limitation is an environmental trigger of the Pseudomonas aeruginosa biofilm lifestyle.

    Directory of Open Access Journals (Sweden)

    Heidi Mulcahy

    Full Text Available Biofilm formation is a conserved strategy for long-term bacterial survival in nature and during infections. Biofilms are multicellular aggregates of cells enmeshed in an extracellular matrix. The RetS, GacS and LadS sensors control the switch from a planktonic to a biofilm mode of growth in Pseudomonas aeruginosa. Here we detail our approach to identify environmental triggers of biofilm formation by investigating environmental conditions that repress expression of the biofilm repressor RetS. Mg(2+ limitation repressed the expression of retS leading to increased aggregation, exopolysaccharide (EPS production and biofilm formation. Repression of retS expression under Mg(2+ limitation corresponded with induced expression of the GacA-controlled small regulatory RNAs rsmZ and rsmY and the EPS biosynthesis operons pel and psl. We recently demonstrated that extracellular DNA sequesters Mg(2+ cations and activates the cation-sensing PhoPQ two-component system, which leads to increased antimicrobial peptide resistance in biofilms. Here we show that exogenous DNA and EDTA, through their ability to chelate Mg(2+, promoted biofilm formation. The repression of retS in low Mg(2+ was directly controlled by PhoPQ. PhoP also directly controlled expression of rsmZ but not rsmY suggesting that PhoPQ controls the equilibrium of the small regulatory RNAs and thus fine-tunes the expression of genes in the RetS pathway. In summary, Mg(2+ limitation is a biologically relevant environmental condition and the first bonafide environmental signal identified that results in transcriptional repression of retS and promotes P. aeruginosa biofilm formation.

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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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

  2. Physiology of Pseudomonas aeruginosa in biofilms as revealed by transcriptome analysis

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    Parker Albert

    2010-11-01

    Full Text Available Abstract Background Transcriptome analysis was applied to characterize the physiological activities of Pseudomonas aeruginosa grown for three days in drip-flow biofilm reactors. Conventional applications of transcriptional profiling often compare two paired data sets that differ in a single experimentally controlled variable. In contrast this study obtained the transcriptome of a single biofilm state, ranked transcript signals to make the priorities of the population manifest, and compared ranki ngs for a priori identified physiological marker genes between the biofilm and published data sets. Results Biofilms tolerated exposure to antibiotics, harbored steep oxygen concentration gradients, and exhibited stratified and heterogeneous spatial patterns of protein synthetic activity. Transcriptional profiling was performed and the signal intensity of each transcript was ranked to gain insight into the physiological state of the biofilm population. Similar rankings were obtained from data sets published in the GEO database http://www.ncbi.nlm.nih.gov/geo. By comparing the rank of genes selected as markers for particular physiological activities between the biofilm and comparator data sets, it was possible to infer qualitative features of the physiological state of the biofilm bacteria. These biofilms appeared, from their transcriptome, to be glucose nourished, iron replete, oxygen limited, and growing slowly or exhibiting stationary phase character. Genes associated with elaboration of type IV pili were strongly expressed in the biofilm. The biofilm population did not indicate oxidative stress, homoserine lactone mediated quorum sensing, or activation of efflux pumps. Using correlations with transcript ranks, the average specific growth rate of biofilm cells was estimated to be 0.08 h-1. Conclusions Collectively these data underscore the oxygen-limited, slow-growing nature of the biofilm population and are consistent with antimicrobial tolerance due

  3. Impact of Pseudomonas aeruginosa quorum sensing on biofilm persistence in an in vivo intraperitoneal foreign-body infection model

    DEFF Research Database (Denmark)

    Christensen, Louise D; Moser, Claus; Jensen, Peter Ø;

    2007-01-01

    of growth contributes significantly to P. aeruginosa tolerance to the action of the innate and adaptive defence system and numerous antibiotics. In the present study, an in vivo foreign-body infection model was established in the peritoneal cavity of mice. Experimental data showed that QS-deficient P...... to the placebo-treated group. These results were obtained with both an inbred (BALB/c) and an outbred (NMRI) mouse strain. The present results support a model by which functional QS systems play a pivotal role in the ability of bacteria to resist clearing by the innate immune system and strongly suggest...... that the efficiency of the mouse innate defence against biofilm-forming P. aeruginosa is improved when the bacteria are treated with QS drugs that induce QS deficiency....

  4. c-di-GMP and its Effects on Biofilm Formation and Dispersion: a Pseudomonas Aeruginosa Review.

    Science.gov (United States)

    Ha, Dae-Gon; O'Toole, George A

    2015-04-01

    Since its initial discovery as an allosteric factor regulating cellulose biosynthesis in Gluconacetobacter xylinus, the list of functional outputs regulated by c-di-GMP has grown. We have focused this article on one of these c-di-GMP-regulated processes, namely, biofilm formation in the organism Pseudomonas aeruginosa. The majority of diguanylate cyclases and phosphodiesterases encoded in the P. aeruginosa genome still remain uncharacterized; thus, there is still a great deal to be learned about the link between c-di-GMP and biofilm formation in this microbe. In particular, while a number of c-di-GMP metabolizing enzymes have been identified that participate in reversible and irreversible attachment and biofilm maturation, there is a still a significant knowledge gap regarding the c-di-GMP output systems in this organism. Even for the well-characterized Pel system, where c-di-GMP-mediated transcriptional regulation is now well documented, how binding of c-di-GMP by PelD stimulates Pel production is not understood in any detail. Similarly, c-di-GMP-mediated control of swimming, swarming and twitching also remains to be elucidated. Thus, despite terrific advances in our understanding of P. aeruginosa biofilm formation and the role of c-di-GMP in this process since the last version of this book (indeed there was no chapter on c-di-GMP!) there is still much to learn.

  5. c-di-GMP and its Effects on Biofilm Formation and Dispersion: a Pseudomonas Aeruginosa Review.

    Science.gov (United States)

    Ha, Dae-Gon; O'Toole, George A

    2015-04-01

    Since its initial discovery as an allosteric factor regulating cellulose biosynthesis in Gluconacetobacter xylinus, the list of functional outputs regulated by c-di-GMP has grown. We have focused this article on one of these c-di-GMP-regulated processes, namely, biofilm formation in the organism Pseudomonas aeruginosa. The majority of diguanylate cyclases and phosphodiesterases encoded in the P. aeruginosa genome still remain uncharacterized; thus, there is still a great deal to be learned about the link between c-di-GMP and biofilm formation in this microbe. In particular, while a number of c-di-GMP metabolizing enzymes have been identified that participate in reversible and irreversible attachment and biofilm maturation, there is a still a significant knowledge gap regarding the c-di-GMP output systems in this organism. Even for the well-characterized Pel system, where c-di-GMP-mediated transcriptional regulation is now well documented, how binding of c-di-GMP by PelD stimulates Pel production is not understood in any detail. Similarly, c-di-GMP-mediated control of swimming, swarming and twitching also remains to be elucidated. Thus, despite terrific advances in our understanding of P. aeruginosa biofilm formation and the role of c-di-GMP in this process since the last version of this book (indeed there was no chapter on c-di-GMP!) there is still much to learn. PMID:26104694

  6. Characterising novel anti-biofilm targets for the treatment of chronic Pseudomonas aeruginosa infection in the cystic fibrosis lung

    OpenAIRE

    McCarthy, Ronan

    2014-01-01

    The global rise in antibiotic resistance is a significant problem facing healthcare professionals. In particular within the cystic fibrosis (CF) lung, bacteria can establish chronic infection and resistance to a wide array of antibiotic therapies. One of the principle pathogens associated with chronic infection in the CF lung is Pseudomonas aeruginosa. P. aeruginosa can establish chronic infection in the CF lung partly through the use of the biofilm mode of growth. This biofilm mode of growth...

  7. 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

    of age, both aggregates and flow-cell biofilm had the same slow growth rate as a stationary phase shaking cultures. Internal structures of the aggregates matrix components and their capacity to survive otherwise lethal treatments with antibiotics (referred to as tolerance) and resistance to phagocytes......, 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...... were also found to be strikingly similar to flow-cell biofilms. Our data indicate that the tolerance of both biofilms and non-attached aggregates towards antibiotics is reversible by physical disruption. We provide evidence that the antibiotic tolerance is likely to be dependent on both...

  8. Effect of bacteriophage infection in combination with tobramycin on the emergence of resistance in Escherichia coli and Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Coulter, Lindsey B; McLean, Robert J C; Rohde, Rodney E; Aron, Gary M

    2014-10-03

    Bacteriophage infection and antibiotics used individually to reduce biofilm mass often result in the emergence of significant levels of phage and antibiotic resistant cells. In contrast, combination therapy in Escherichia coli biofilms employing T4 phage and tobramycin resulted in greater than 99% and 39% reduction in antibiotic and phage resistant cells, respectively. In P. aeruginosa biofilms, combination therapy resulted in a 60% and 99% reduction in antibiotic and PB-1 phage resistant cells, respectively. Although the combined treatment resulted in greater reduction of E. coli CFUs compared to the use of antibiotic alone, infection of P. aeruginosa biofilms with PB-1 in the presence of tobramycin was only as effective in the reduction of CFUs as the use of antibiotic alone. The study demonstrated phage infection in combination with tobramycin can significantly reduce the emergence of antibiotic and phage resistant cells in both E. coli and P. aeruginosa biofilms, however, a reduction in biomass was dependent on the phage-host system.

  9. Dynamics of Mutator and Antibiotic-Resistant Populations in a Pharmacokinetic/Pharmacodynamic Model of Pseudomonas aeruginosa Biofilm Treatment

    DEFF Research Database (Denmark)

    Macià, María D.; Pérez, José L.; Molin, Søren;

    2011-01-01

    Biofilm growth, antibiotic resistance, and mutator phenotypes are key components of chronic respiratory infections by Pseudomonas aeruginosa in cystic fibrosis patients. We examined the dynamics of mutator and antibiotic-resistant populations in P. aeruginosa flow-cell biofilms, using fluorescently...... monitored by confocal laser scanning microscopy (CLSM), and the numbers of viable cells and resistant mutants (4- and 16-fold MICs) were determined. Despite optimized pharmacokinetic/pharmacodynamic (PK/PD) parameters, CIP treatment did not suppress resistance development in P. aeruginosa biofilms. One.......01 proportion, took over the whole biofilm after only 2 days of CIP treatment outnumbering PAO1 by 3 log at t4. Our results show that mutational mechanisms play a major role in biofilm antibiotic resistance and that theoretically optimized PK/PD parameters fail to suppress resistance development, suggesting...

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

    Science.gov (United States)

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

    2015-09-01

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

  11. Antimicrobial and anti-biofilm effect of a novel BODIPY photosensitizer against Pseudomonas aeruginosa PAO1

    DEFF Research Database (Denmark)

    Orlandi, Viviana Teresa; Rybtke, Morten; Caruso, Enrico;

    2014-01-01

    Photodynamic therapy (PDT) combines the use of organic dyes (photosensitizers, PSs) and visible light in order to elicit a photo-oxidative stress which causes bacterial death. GD11, a recently synthesized PS belonging to the boron-dipyrromethene (BODIPY) class, was demonstrated to be efficient...... against planktonic cultures of Pseudomonas aeruginosa, causing a 7 log unit reduction of viable cells when administered at 2.5 μM. The effectiveness of GD11 against P. aeruginosa biofilms grown in flow-cells and microtiter trays was also demonstrated. Confocal laser scanning microscopy of flow...

  12. Influence of O polysaccharides on biofilm development and outer membrane vesicle biogenesis in Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Murphy, Kathleen; Park, Amber J; Hao, Youai; Brewer, Dyanne; Lam, Joseph S; Khursigara, Cezar M

    2014-04-01

    Pseudomonas aeruginosa is a common opportunistic human pathogen known for its ability to adapt to changes in its environment during the course of infection. These adaptations include changes in the expression of cell surface lipopolysaccharide (LPS), biofilm development, and the production of a protective extracellular exopolysaccharide matrix. Outer membrane vesicles (OMVs) have been identified as an important component of the extracellular matrix of P. aeruginosa biofilms and are thought to contribute to the development and fitness of these bacterial communities. The goal of this study was to examine the relationships between changes in the cell surface expression of LPS O polysaccharides, biofilm development, and OMV biogenesis in P. aeruginosa. We compared wild-type P. aeruginosa PAO1 with three chromosomal knockouts. These knockouts have deletions in the rmd, wbpM, and wbpL genes that produce changes in the expression of common polysaccharide antigen (CPA), O-specific antigen (OSA), or both. Our results demonstrate that changes in O polysaccharide expression do not significantly influence OMV production but do affect the size and protein content of OMVs derived from both CPA(-) and OSA(-) cells; these mutant cells also exhibited different physical properties from wild-type cells. We further examined biofilm growth of the mutants and determined that CPA(-) cells could not develop into robust biofilms and exhibit changes in cell morphology and biofilm matrix production. Together these results demonstrate the importance of O polysaccharide expression on P. aeruginosa OMV composition and highlight the significance of CPA expression in biofilm development. PMID:24464462

  13. Alginate is not a significant component of the extracellular polysaccharide matrix of PA14 and PAO1 Pseudomonas aeruginosa biofilms

    OpenAIRE

    Wozniak, Daniel J.; Wyckoff, Timna J. O.; Starkey, Melissa; Keyser, Rebecca; Azadi, Parastoo; O'Toole, George A.; Parsek, Matthew R.

    2003-01-01

    The bacterium Pseudomonas aeruginosa causes chronic respiratory infections in cystic fibrosis (CF) patients. Such infections are extremely difficult to control because the bacteria exhibit a biofilm-mode of growth, rendering P. aeruginosa resistant to antibiotics and phagocytic cells. During the course of infection, P. aeruginosa usually undergoes a phenotypic switch to a mucoid colony, which is characterized by the overproduction of the exopolysaccharide alginate. Alginate overproducti...

  14. Predictive Computer Models for Biofilm Detachment Properties in Pseudomonas aeruginosa.

    Science.gov (United States)

    Cogan, Nick G; Harro, Janette M; Stoodley, Paul; Shirtliff, Mark E

    2016-01-01

    Microbial biofilm communities are protected against environmental extremes or clearance by antimicrobial agents or the host immune response. They also serve as a site from which microbial populations search for new niches by dispersion via single planktonic cells or by detachment by protected biofilm aggregates that, until recently, were thought to become single cells ready for attachment. Mathematically modeling these events has provided investigators with testable hypotheses for further study. Such was the case in the recent article by Kragh et al. (K. N. Kragh, J. B. Hutchison, G. Melaugh, C. Rodesney, A. E. Roberts, Y. Irie, P. Ø. Jensen, S. P. Diggle, R. J. Allen, V. Gordon, and T. Bjarnsholt, mBio 7:e00237-16, 2016, http://dx.doi.org/10.1128/mBio.00237-16), in which investigators were able to identify the differential competitive advantage of biofilm aggregates to directly attach to surfaces compared to the single-celled planktonic populations. Therefore, as we delve deeper into the properties of the biofilm mode of growth, not only do we need to understand the complexity of biofilms, but we must also account for the properties of the dispersed and detached populations and their effect on reseeding. PMID:27302761

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

    Directory of Open Access Journals (Sweden)

    Kohlmann Thomas

    2010-11-01

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

  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. Characterization of membrane lipidome changes in Pseudomonas aeruginosa during biofilm growth on glass wool.

    Directory of Open Access Journals (Sweden)

    Hayette Benamara

    Full Text Available Bacteria cells within biofilms are physiologically distinct from their planktonic counterparts. In particular they are more resistant to detrimental environmental conditions. In this study, we monitored the evolution of the phospholipid composition of the inner and outer membranes of P. aeruginosa during the biofilm formation (i.e., from 1-, 2-, to 6-day-old biofilm. Lipidome analyses were performed by electrospray ionization mass spectrometry. In addition to the lipidomic analysis, the fatty acid composition was analysed by gas chromatography/mass spectrometry. We found that the lipidome alterations of the inner and the outer membranes varied with the biofilm age. These alterations in phospholipid compositions reflect a higher diversity in sessile organisms than in planktonic counterparts. The diversity is characterized by the presence of PE 30∶1, PE 31∶0 and PG 31∶0 for the lower masses as well as PE 38∶1, 38∶2, 39∶1, 39∶2 and PG 38∶0, 38∶1, 38∶2, 39∶1, 39∶2 for the higher masses. However, this lipidomic feature tends to disappear with the biofilm age, in particular the high mass phospholipids tend to disappear. The amount of branched chains phospholipids mainly located in the outer membrane decreased with the biofilm age, whereas the proportion of cyclopropylated phospholipids increased in both membranes. In bacteria present in oldest biofilms, i.e., 6-day-old, the phospholipid distribution moved closer to that of planktonic bacteria.

  18. Characterization of membrane lipidome changes in Pseudomonas aeruginosa during biofilm growth on glass wool.

    Science.gov (United States)

    Benamara, Hayette; Rihouey, Christophe; Abbes, Imen; Ben Mlouka, Mohamed Amine; Hardouin, Julie; Jouenne, Thierry; Alexandre, Stéphane

    2014-01-01

    Bacteria cells within biofilms are physiologically distinct from their planktonic counterparts. In particular they are more resistant to detrimental environmental conditions. In this study, we monitored the evolution of the phospholipid composition of the inner and outer membranes of P. aeruginosa during the biofilm formation (i.e., from 1-, 2-, to 6-day-old biofilm). Lipidome analyses were performed by electrospray ionization mass spectrometry. In addition to the lipidomic analysis, the fatty acid composition was analysed by gas chromatography/mass spectrometry. We found that the lipidome alterations of the inner and the outer membranes varied with the biofilm age. These alterations in phospholipid compositions reflect a higher diversity in sessile organisms than in planktonic counterparts. The diversity is characterized by the presence of PE 30∶1, PE 31∶0 and PG 31∶0 for the lower masses as well as PE 38∶1, 38∶2, 39∶1, 39∶2 and PG 38∶0, 38∶1, 38∶2, 39∶1, 39∶2 for the higher masses. However, this lipidomic feature tends to disappear with the biofilm age, in particular the high mass phospholipids tend to disappear. The amount of branched chains phospholipids mainly located in the outer membrane decreased with the biofilm age, whereas the proportion of cyclopropylated phospholipids increased in both membranes. In bacteria present in oldest biofilms, i.e., 6-day-old, the phospholipid distribution moved closer to that of planktonic bacteria. PMID:25265483

  19. Association of biofilm production with multidrug resistance among clinical isolates of Acinetobacter baumannii and Pseudomonas aeruginosa from intensive care unit

    Directory of Open Access Journals (Sweden)

    Jeetendra Gurung

    2013-01-01

    Full Text Available Background and Aims: Given choice, bacteria prefer a community-based, surface-bound colony to an individual existence. The inclination for bacteria to become surface bound is so ubiquitous in diverse ecosystems that it suggests a strong survival strategy and selective advantage for surface dwellers over their free-ranging counterparts. Virtually any surface, biotic or abiotic (animal, mineral, or vegetable is suitable for bacterial colonization and biofilm formation. Thus, a biofilm is "a functional consortium of microorganisms organized within an extensive exopolymeric matrix." Materials and Methods: The present study was undertaken to detect biofilm production from the repertoire stocks of Acinetobacter baumannii (A. baumannii and Pseudomonas aeruginosa (P. aeruginosa obtained from clinical specimens. The tube method was performed to qualitatively detect biofilm production. Results: A total of 109 isolates of both organisms were included in the study, out of which 42% (46/109 isolates showed biofilm detection. Among the biofilm producers, 57% of P. aeruginosa and 73% of A. baumannii showed multidrug resistance (MDR pattern which was statistically significant in comparison to nonbiofilm producers (P < 0.001. Conclusion: To the best of our knowledge, this is the only study to have tested the biofilm production in both P. aeruginosa and A. baumannii in a single study. Biofilm production and MDR pattern were found to be significantly higher in A. baumannii than P. aeruginosa. Antibiotic resistance was significantly higher among biofilm producing P. aeruginosa than non producers. Similarly, antibiotic resistance was significantly higher among biofilm producing A. baumannii than non producers.

  20. Effects of houttuyfonate sodium on eliminating adhesion of Psedomonas aeruginosa and forming biofilms%鱼腥草素钠对铜绿假单胞菌黏附的清除作用及对生物被膜形成的影响

    Institute of Scientific and Technical Information of China (English)

    程惠娟; 汪长中; 卢文波; 胡跃龙; 高磊; 朱玲玲

    2012-01-01

    Objective: To investigate the effect of houttuyfonate sodium (HS) on eliminating adhesion of Psedomonas aeruginosa ( Pa) and forming biofilms. Method: Pa biofilms were established in 96-hold plates. MTT assay was used to evaluate the changes in metabolism of biofilms am! assess the minimum eliminating concentration and minimum bsofilm inhibitory concentration for adherent Pa. The colony counting method was used to observe the effect of HS on Pa adhesion and biomass in biofilms. SEM was employed to examine the effect of HS on adhesion of tested Pa and morphology of biofilms. Result: MECg80 and MEC50 of HS for adherent Pa was 500 mg · L-1 and 125 mg · L-1 , respectively. Meanwhile, its SMIC80 for either early or mature biofilras of Pa was 500 mg · L-1 , and SMIC50 for early and mature biofilms of Pa were 31. 25 , 1. 95 mg · L-1 , respectively. At the concentration of 250 mg · L-1 , the number of viable bacteria in the state of adhesion and in initial and mature biofilms decreased significantly, compared with the control group (P<0. 05). The number of bacteria on adherent carriers notably reduced under SEM. Following the continuous administration, there were no visible biofilms on carriers in the mature biofilm phase, with the biomass remarkably shrinking and the bacterial morphology changing from bacillus into coccobacillus. Conclusion: HS displayed powerful effect on eliminating adherent Pa, and can inhibit Pa biofilm from being formed through continuous administration.%目的:研究鱼腥草素钠( houttuyfonate sodium,SH)对铜绿假单胞菌(Pseudomonas aeruginosa,Pa)黏附的清除作用及对生物被膜( biofilm,BF)形成的影响.方法:用96孔板孔建立铜绿假单胞菌黏附生物被膜,MTT法检测膜内菌的代谢变化、评价药物对黏附菌的最小清除浓度( minimum eliminateing concentration,MEC)及最小抑膜浓度(sessile minimal inhibitory concentration,SMIC);菌落计数法观察药物对黏附、膜内菌量影响;扫描电

  1. The inhibition of Pseudomonas aeruginosa biofilm formation by micafungin and the enhancement of antimicrobial agent effectiveness in BALB/c mice.

    Science.gov (United States)

    Kissoyan, Kohar Annie B; Bazzi, Wael; Hadi, Usamah; Matar, Ghassan M

    2016-08-01

    Micafungin inhibits biofilm formation by impeding 1,3-β-D-glucan synthesis in Candida albicans. Since Pseudomonas aeruginosa also has 1,3-β-D-glucan in its cell wall, this study assessed the effects of antibacterial agents in vitro and in vivo on micafungin-treated biofilm-forming P. aeruginosa isolates. After treatment with micafungin as well as with a panel of four antibacterial agents, biofilm production was significantly reduced as measured by spectrophotometry. The relative mRNA transcription levels for the genes encoding pellicles (pelC) and cell wall 1,3-β-D-glucan (ndvB), which were measured by quantitative reverse transcription PCR (qRT-PCR), significantly decreased with micafungin treatment. In vivo, the survival rates of P. aeruginosa-infected BALB/c mice significantly increased after combined treatment with micafungin and each of the antibacterial agents. Of these treatments, the combination of micafungin with levofloxacin had the highest survival rate; this combination was the most effective treatment against P. aeruginosa-induced infection. PMID:27347641

  2. Inhibition of Acinetobacter baumannii, Staphylococcus aureus and Pseudomonas aeruginosa biofilm formation with a class of TAGE-triazole conjugates.

    Science.gov (United States)

    Huigens, Robert W; Rogers, Steven A; Steinhauer, Andrew T; Melander, Christian

    2009-02-21

    A chemically diverse library of TAGE-triazole conjugates was synthesized utilizing click chemistry on the TAGE scaffold. This library of small molecules was screened for anti-biofilm activity and found to possess the ability of inhibiting biofilm formation against Acinetobacter baumannii, Staphylococcus aureus and Pseudomonas aeruginosa. One such compound in this library demonstrated the most potent inhibitory effect against Staphylococcus aureus biofilm formation that has been displayed by any 2-aminoimidazole derivative. PMID:19194596

  3. The metabolically active subpopulation in Pseudomonas aeruginosa biofilms survives exposure to membrane-targeting antimicrobials via distinct molecular mechanisms

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Pamp, Sünje Johanna; Nilsson, Martin;

    2012-01-01

    have found that membrane-targeting antimicrobials such as colistin, EDTA, SDS, and chlorhexidine specifically kill the inactive subpopulation in P. aeruginosa biofilms, whereas the active subpopulation survives exposure to these compounds. Because treatment of P. aeruginosa biofilms with the membrane......-targeting compounds colistin, EDTA, SDS, and chlorhexidine resulted in the same spatial distribution of live and dead bacteria, we investigated whether tolerance to these compounds originated from the same molecular mechanisms. Development of colistin-tolerant subpopulations was found to depend on the pmr genes......, but does not depend on the pmr, mexAB-oprM, mexPQ-opmE, or muxABC-opmB genes. Tolerance to SDS and EDTA in P. aeruginosa biofilms is linked to metabolically active cells, but does not depend on the pmr, mexAB, mexCD, mexPQ, or muxABC genes. Our data suggest that the active subpopulation in P. aeruginosa...

  4. Anti-Biofilm and Immunomodulatory Activities of Peptides That Inhibit Biofilms Formed by Pathogens Isolated from Cystic Fibrosis Patients

    OpenAIRE

    César de la Fuente-Núñez; Sarah C. Mansour; Zhejun Wang; Lucy Jiang; Breidenstein, Elena B. M.; Melissa Elliott; Fany Reffuveille; Speert, David P.; Reckseidler-Zenteno, Shauna L.; Ya Shen; Markus Haapasalo; Robert E W Hancock

    2014-01-01

    Cystic fibrosis (CF) patients often acquire chronic respiratory tract infections due to Pseudomonas aeruginosa and Burkholderia cepacia complex (Bcc) species. In the CF lung, these bacteria grow as multicellular aggregates termed biofilms. Biofilms demonstrate increased (adaptive) resistance to conventional antibiotics, and there are currently no available biofilm-specific therapies. Using plastic adherent, hydroxyapatite and flow cell biofilm models coupled with confocal and scanning electro...

  5. Pseudomonas aeruginosa biofilms exposed to imipenem exhibit changes in global gene expression and beta-lactamase and alginate production

    DEFF Research Database (Denmark)

    Bagge, Niels; Schuster, Martin; Hentzer, Morten;

    2004-01-01

    expression in biofilm populations. Many genes showed small but statistically significant differential expression in response to imipenem. We identified 34 genes that were induced or repressed in biofilms exposed to imipenem more than fivefold compared to the levels of induction or repression for the controls......The lungs of cystic fibrosis (CF) patients are commonly colonized with Pseudomonas aeruginosa biofilms. Chronic endobronchial P. aeruginosa infections are impossible to eradicate with antibiotics, but intensive suppressive antibiotic therapy is essential to maintain the lung function of CF patients....... The treatment often includes beta-lactam antibiotics. How these antibiotics influence gene expression in the surviving biofilm population of P. aeruginosa is not clear. Thus, we used the microarray technology to study the effects of subinhibitory concentrations of a beta-lactam antibiotic, imipenem, on gene...

  6. A peptide from human β thymosin as a platform for the development of new anti-biofilm agents for Staphylococcus spp. and Pseudomonas aeruginosa.

    Science.gov (United States)

    Schillaci, Domenico; Spinello, Angelo; Cusimano, Maria Grazia; Cascioferro, Stella; Barone, Giampaolo; Vitale, Maria; Arizza, Vincenzo

    2016-08-01

    Conventional antibiotics might fail in the treatment of biofilm-associated infections causing infection recurrence and chronicity. The search for antimicrobial peptides has been performed with the aim to discover novel anti-infective agents active on pathogens in both planktonic and biofilm associated forms. The fragment 9-19 of human thymosin β4 was studied through 1 μs MD simulation. Two main conformations of the peptide were detected, both constituted by a central hydrophobic core and by the presence of peripheral charged residues suggesting a possible mechanism of interaction with two models of biological membranes, related to eukaryotic or bacterial membrane respectively. In addition, the peptide was chemically synthesized and its antimicrobial activity was tested in vitro against planktonic and biofilm form of a group of reference strains of Staphylococcus spp. and one P. aeruginosa strain. The human thymosin β4 fragment EIEKFDKSKLK showed antibacterial activity against staphylococcal strains and Pseudomonas aeruginosa ATCC 15442 at concentrations from 12.5 to 6.2 mg/ml and inhibited biofilm formation at sub-inhibitory concentrations (3.1-0.75 mg/ml). The activity of the fragment in inhibiting biofilm formation, could be due to the conformations highlighted by the MD simulations, suggesting its interaction with the bacterial membrane. Human thymosin β4 fragment can be considered a promising lead compound to develop novel synthetic or recombinant derivatives with improved pharmaceutical potential. PMID:27339305

  7. Effects of Combined Treatment with Sansanmycin and Macrolides on Pseudomonas aeruginosa and Formation of Biofilm

    Institute of Scientific and Technical Information of China (English)

    YUE LI; YUN-YING XIE; RU-XIAN CHEN; HONG-ZHANG XU; GUO-JI ZHANG; JIN-ZHE LI; XIAO-MIAN LI

    2009-01-01

    Objective To observe the effects of combined treatment with sansanmycin and macrolides on Pseudomonas aeruginosa and formation of biofilm. Methods Micro-dilution method was used to determine the minimal inhibitory concentrations (MICs) of sansanmycin, gentamycin, carbenicillin, polymyxin B, roxithromycin, piperacillin, and tazobactam. PA1 and PA27853 biofilms were observed under optical microscope after staining and under SEM after treatment with sansanmycin at different dosages and combined treatment with sansanmycin and roxithromycin. Viable bacteria in PA1 and PA27853 biofilms were counted after treatment with sansanmycin at different dosages or combined treatment with sansanmycin and roxithromycin. Results The MIC of sansanmycin was lower than that of gentamycin and polymyxin B, but was higher than that of carbenicillin. Roxithromycin enhanced the penetration of sansanmycin to PA1 and PA27853 strains through biofilms. PA1 and PA27853 biofilms were gradually cleared with the increased dosages of sansanmycin or with the combined sansanmycin and roxithromycin. Conclusion Sub-MIC levels of roxithromycin and sansanmycin substantially inhibit the generation of biofilms and proliferation of bacteria. Therefore, combined antibiotics can be used in treatment of intractable bacterial infection.

  8. Prevalence of Pseudomonas aeruginosa and Acinetobacter spp. in subgingival biofilm and saliva of subjects with chronic periodontal infection

    Directory of Open Access Journals (Sweden)

    Renata Souto

    2014-06-01

    Full Text Available P. aeruginosa and Acinetobacter spp. are important pathogens associated with late nosocomial pneumonia in hospitalized and institutionalized individuals. The oral cavity may be a major source of these respiratory pathogens, particularly in the presence of poor oral hygiene and periodontal infection. This study investigated the prevalence of P. aeruginosa and Acinetobacter spp. in subgingival biofilm and saliva of subjects with periodontal disease or health. Samples were obtained from 55 periodontally healthy (PH and 169 chronic periodontitis (CP patients. DNA was obtained from the samples and detection of P. aeruginosa and Acinetobacter spp. was carried out by multiplex and nested PCR. P. aeruginosa and Acinetobacter spp. were detected in 40% and 45% of all samples, respectively. No significant differences in the distribution of these microorganisms between men and women, subgingival biofilm and saliva samples, patients 35 years of age, and smokers and non-smokers were observed regardless periodontal status (p > 0.05. In contrast, the frequencies of P. aeruginosa and Acinetobacter spp. in saliva and biofilm samples were significantly greater in CP than PH patients (p < 0.01. Smokers presenting P. aeruginosa and high frequencies of supragingival plaque were more likely to present CP than PH. P. aeruginosa and Acinetobacter spp. are frequently detected in the oral microbiota of CP. Poor oral hygiene, smoking and the presence of P. aeruginosa are strongly associated with periodontitis.

  9. In vivo pharmacokinetics/pharmacodynamics of colistin and imipenem in Pseudomonas aeruginosa biofilm infection

    DEFF Research Database (Denmark)

    Hengzhuang, Wang; Wu, Hong; Ciofu, Oana;

    2012-01-01

    Many Pseudomonas aeruginosa isolates from the airways of patients with cystic fibrosis (CF) are sensitive to antibiotics in susceptibility testing, but eradication of the infection is difficult. The main reason is the biofilm formation in the airways of patients with CF. The pharmacokinetics (PKs......) and pharmacodynamics (PDs) of antimicrobials can reliably be used to predict whether antimicrobial regimens will achieve the maximum bactericidal effect against infections. Unfortunately, however, most PK/PD studies of antimicrobials have been done on planktonic cells and very few PK/PD studies have been done...... on biofilms, partly due to the lack of suitable models in vivo. In the present study, a biofilm lung infection model was developed to provide an objective and quantitative evaluation of the PK/PD profile of antimicrobials. Killing curves were set up to detect the antimicrobial kinetics on planktonic...

  10. An investigation of Pseudomonas aeruginosa biofilm growth on novel nanocellulose fibre dressings.

    Science.gov (United States)

    Powell, Lydia C; Khan, Saira; Chinga-Carrasco, Gary; Wright, Chris J; Hill, Katja E; Thomas, David W

    2016-02-10

    Nanocellulose from wood is a novel biomaterial, which is highly fibrillated at the nanoscale. This affords the material a number of advantages, including self-assembly, biodegradability and the ability to absorb and retain moisture, which highlights its potential usefulness in clinical wound-dressing applications. In these in vitro studies, the wound pathogen Pseudomonas aeruginosa PAO1 was used to assess the ability of two nanocellulose materials to impair bacterial growth (nanocelluloses had a relatively small fraction of residual fibres (nanocellulose films and increased cell death when compared to a commercial control wound dressing, Aquacel(®). Nanocellulose suspensions inhibited bacterial growth, whilst UV-vis spectrophotometry and laser profilometry also revealed the ability of nanocellulose to form smooth, translucent films. Atomic force microscopy studies of the surface properties of nanocellulose demonstrated that PAO1 exhibited markedly contrasting morphology when grown on the nanocellulose film surfaces compared to an Aquacel(®) control dressing (p<0.05). This study highlights the potential utility of these biodegradable materials, from a renewable source, for wound dressing applications in the prevention and treatment of biofilm development. PMID:26686120

  11. Antibacterial activity of Espand (Peganum harmala alcoholic extracts against six pathogenic bacteria in planktonic and biofilm forms

    Directory of Open Access Journals (Sweden)

    Zinab Mohsenipour

    2016-03-01

    Full Text Available Introduction: Microbial biofilms have attracted interest in recent years because they have become the most important cause of nosocomial infections. This study was aimed to examine the antibacterial activities of Peganum harmala extracts on the development of microbial biofilms and planktonic form of six pathogenic bacteria which include Staphylococcus aureus, Bacillus cereus, Streptococcus pneumoniae, Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae. Materials and methods: Antimicrobial activities of the crude extracts against the planktonic form of bacteria were evaluated by using disc diffusion method, minimum inhibitory concentration (MIC and the minimum bactericidal concentration (MBC values were determined by a macrobroth dilution technique. Anti- biofilm effects of the extracts were assessed by microtiter plate method. Results: According to the results, P. harmala extracts could inhibit test bacteria in planktonic form. To inhibit biofilm formation, biofilm metabolic activity and eradication of established biofilms, efficiency of the extracts depended on concentration. The highest inhibitory effects of P. harmala extracts were observed on biofilm formation of S. aureus (90.28% also, the greatest demolish were observed on S. pneumonia biofilm (77.76%. These extracts cause dramatically decrease the metabolic activity of bacteria in biofilm structures, in this case the decrement of B. cereus were highest (69.98% compared to other tested bacteria. Discussion and conclusion: Therefore, it can be suggested that P.harmala extracts applied as antimicrobial agents against testing bacteria particularly in biofilm forms

  12. In vitro antimicrobial activity of Pseudomonas aeruginosa by-products against single and mixed biofilms : the role of Gram- bacteria in the biofilm consortium

    OpenAIRE

    Pereira, Maria Olívia; Machado, Idalina; Lopes, Susana Patrícia

    2010-01-01

    Since bacteria are permanently acquiring resistance to chemicals, the development of novel strategies for biofilm control is needed. Certain microorganisms represent an important source of novel bioactive compounds with marked antibacterial activity, as the secondary metabolites. This work aimed to investigate the antimicrobial effect of P.aeruginosa by-products on planktonic and sessile growth of several pathogenic bacteria. Supernatants from P.aeruginosa planktonic cultures (iso...

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

    Science.gov (United States)

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

    2013-10-29

    Quorum sensing is a chemical communication process that bacteria use to regulate collective behaviors. Disabling quorum-sensing circuits with small molecules has been proposed as a potential strategy to prevent bacterial pathogenicity. The human pathogen Pseudomonas aeruginosa uses quorum sensing to control virulence and biofilm formation. Here, we analyze synthetic molecules for inhibition of the two P. aeruginosa quorum-sensing receptors, LasR and RhlR. Our most effective compound, meta-bromo-thiolactone (mBTL), inhibits both the production of the virulence factor pyocyanin and biofilm formation. mBTL also protects Caenorhabditis elegans and human lung epithelial cells from killing by P. aeruginosa. Both LasR and RhlR are partially inhibited by mBTL in vivo and in vitro; however, RhlR, not LasR, is the relevant in vivo target. More potent antagonists do not exhibit superior function in impeding virulence. Because LasR and RhlR reciprocally control crucial virulence factors, appropriately tuning rather than completely inhibiting their activities appears to hold the key to blocking pathogenesis in vivo.

  14. Adsorption to metal oxides of the Pseudomonas aeruginosa siderophore pyoverdine and implications for bacterial biofilm formation on metals.

    Science.gov (United States)

    Upritchard, Hamish G; Yang, Jing; Bremer, Philip J; Lamont, Iain L; McQuillan, A James

    2007-06-19

    The initiation of biofilm formation is poorly understood, and in particular, the contribution of chemical bond formation between bacterial cells and metal surfaces has received little attention. We have previously used in situ infrared spectroscopy to show, during the initial stages of Pseudomonas aeruginosa biofilm formation, the formation of coordinate covalent bonds between titanium dioxide particle films and pyoverdine, a mixed catecholate and hydroxamate siderophore. Here we show using infrared spectroscopy that pyoverdine can also form covalent bonds with particle films of Fe2O3, CrOOH, and AlOOH. Adsorption to the metal oxides through the catechol-like 2,3-diamino-6,7-dihydroxyquinoline part of pyoverdine was most evident in the infrared spectrum of the adsorbed pyoverdine molecule. Weaker infrared absorption bands that are consistent with the hydroxamic acids of pyoverdine binding covalently to TiO2, Fe2O3, and AlOOH surfaces were also observed. The adsorption of pyoverdine to TiO2 and Fe2O3 surfaces showed a pH dependence that is indicative of the dominance of the catechol-like ligand of pyoverdine. Infrared absorption bands were also evident for pyoverdine associated with the cells of P. aeruginosa on TiO2 and Fe2O3 surfaces and were notably absent for genetically modified cells unable to synthesize or bind pyoverdine at the cell surface. These studies confirm the generality of pyoverdine-metal bond formation and suggest a wider involvement of siderophores in bacterial biofilm initiation on metals.

  15. Rapid development in vitro and in vivo of resistance to ceftazidime in biofilm-growing Pseudomonas aeruginosa due to chromosomal beta-lactamase

    DEFF Research Database (Denmark)

    Bagge, N; Ciofu, O; Skovgaard, L T;

    2000-01-01

    The aim of this study was to examine the development of resistance of biofilm-growing P. aeruginosa during treatment with ceftazidime. Biofilms were established in vitro using a modified Robbins device (MRD) and in vivo in the rat model of chronic lung infection. Three P. aeruginosa strains...

  16. Effects of quorum sensing autoinducer degradation gene on virulence and biofilm formation of Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The aiiA gene from Bacillus thuringiensis was cloned into the Pseudomonas/E. coli shuttle vector and transformed into Pseudomonas aeruginosa strain PAO1. Western blotting showed that the AiiA protein was expressed in PAO1. After induction by IPTG for 6 h and 18 h, expression of the aiiA gene in PAO1 completely degraded the quorum sensing autoinducers N-acylhomoserine lactones (AHLs): N-oxododecanoyl-L-homoserine lactone (OdDHL) and N-butyryl-L-homoserine lactone (BHL). The re- duced amount of AHLs in PAO1 was also correlated with decreased expression and production of several virulence factors such as elastase and pyocyanin. AiiA expression also influenced bacterial swarming motility. Most importantly, our studies indicated that aiiA played significant roles in P. aeruginosa biofilm formation and dispersion, as observed by the differences of the biofilm formation on liquid and solid surfaces, and biofilm structures under a scanning electron microscope.

  17. Effects of quorum sensing autoinducer degradation gene on virulence and biofilm formation of Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    WANG Yao; DAI Yue; ZHANG Yong; HU YangBo; YANG BaoYu; CHEN ShiYun

    2007-01-01

    The aiiA gene from Bacillus thuringiensis was cloned into the Pseudomonas/E. coli shuttle vector and transformed into Pseudomonas aeruginosa strain PAO1. Western blotting showed that the AiiA protein was expressed in PAO1. After induction by IPTG for 6 h and 18 h, expression of the aiiA gene in PAO1completely degraded the quorum sensing autoinducers N-acylhomoserine lactones (AHLs):N-oxododecanoyI-L-homoserine lactone (OdDHL) and N-butyryI-L-homoserine lactone (BHL). The reduced amount of AHLs in PAO1 was also correlated with decreased expression and production of several virulence factors such as elastase and pyocyanin. AiiA expression also influenced bacterial swarming motility. Most importantly, our studies indicated that aiiA played significant roles in P.aeruginosa biofilm formation and dispersion, as observed by the differences of the biofilm formation on liquid and solid surfaces, and biofilm structures under a scanning electron microscope.

  18. Pathogenic effects of biofilm with chronic pseudomonas aeruginosa lung infection in rats

    Institute of Scientific and Technical Information of China (English)

    Ping Yan; Yiqiang Chen; Zhijun Song; Hong Wu; Jinliang Kong; Xuejun Qin

    2008-01-01

    Objective: To establish an animal model of P.aeruginosa biofilm associated with chronic pulmonary infection and investigate the pathogenic effects of biofilm. Methods: Experiments in vitro, measuring the MICS, MBCS of ievofloxacin(LFX), ceftazidime(CAZ) in PAO579 in alginate beads and planktonic PAO579. Rats were challenged with 0.1 ml of PAO579(109CFU/ml) in alginate beads or 0.1 ml of planktonic PAO579(109CFU/ml), 3,7,14 days after challenging, bacteriological, pathological features were observed. Results: The MICS, MBCS of LFX, CAZ in PAO579 in alginate beads were higher than those in planktonic PAO579 in vitro. CFU/lung in alginate beads group was significantly higher than that in planktonic bacteria group(P = 0.002, P =0.004, P = 0.002, respectively); macroscopic lung pathology and the inflammation in alginate beads group were significantly more severe compared to those in planktonic bacteria group in vivo. Conclusion: P.aeruginosa biofilm protected bacterium from killing of antibiotics and might mediate the host immune damage in the lung tissue and made bacterium evade the host immune defense.

  19. The In Vitro Susceptibility of Biofilm Forming Medical Device Related Pathogens to Conventional Antibiotics

    Directory of Open Access Journals (Sweden)

    Garry Laverty

    2014-01-01

    Full Text Available Minimum inhibitory concentration (MIC, minimum bactericidal concentration (MBC, and minimum biofilm eradication concentration (MBEC and kill kinetics were established for vancomycin, rifampicin, trimethoprim, gentamicin, and ciprofloxacin against the biofilm forming bacteria Staphylococcus epidermidis (ATCC 35984, Staphylococcus aureus (ATCC 29213, Methicillin Resistant Staphylococcus aureus (MRSA (ATCC 43300, Pseudomonas aeruginosa (PAO1, and Escherichia coli (NCTC 8196. MICs and MBCs were determined via broth microdilution in 96-well plates. MBECs were studied using the Calgary Biofilm Device. Values obtained were used to investigate the kill kinetics of conventional antimicrobials against a range of planktonic and biofilm microorganisms over a period of 24 hours. Planktonic kill kinetics were determined at 4xMIC and biofilm kill kinetics at relative MBECs. Susceptibility of microorganisms varied depending on antibiotic selected and phenotypic form of bacteria. Gram-positive planktonic isolates were extremely susceptible to vancomycin (highest MBC: 7.81 mg L−1: methicillin sensitive and resistant S. aureus but no MBEC value was obtained against all biofilm pathogens tested (up to 1000 mg L−1. Both gentamicin and ciprofloxacin displayed the broadest spectrum of activity with MIC and MBCs in the mg L−1 range against all planktonic isolates tested and MBEC values obtained against all but S. epidermidis (ATCC 35984 and MRSA (ATCC 43300.

  20. Presence of exoY, exoS, exoU and exoT genes, antibiotic resistance and biofilm production among Pseudomonas aeruginosa isolates in Northwest Iran

    OpenAIRE

    Azimi, Somayeh; Kafil, Hossein Samadi; Baghi, Hossein Bannazadeh; Shokrian, Saeed; Najaf, Khadijeh; ASGHARZADEH, Mohammad; Yousefi, Mehdi; Shahrivar, Firooz; Aghazadeh, Mohammad

    2016-01-01

    Background: Pseudomonas aeruginosa, as Gram-negative rod bacilli, has an important role in human infection. In the present study we aimed to investigate the presence of exo genes and biofilm production among Pseudomonas aeruginosa isolates in Northwest Iran. Material and methods: 160 isolates of P. aeruginosa were collected and identified by biochemical tests and were characterized for antibiotic resistance. Biofilm production was evaluated by microtiter plate assay and the presence of exo ge...

  1. 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

    were used to visualize AHL-mediated communication in mixed biofilms, which were cultivated either in artificial flow chambers or in alginate beads in mouse lung tissue. In both model systems B. cepacia was capable of perceiving the AHL signals produced by A aeruginosa, while the latter strain did...... not respond to the molecules produced by B. cepacia. Measurements of extracellular proteolytic activities of defined quorum-sensing mutants grown in media complemented with AHL extracts prepared from culture supernatants of various wild-type and mutant strains supported the view of unidirectional signalling...

  2. 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

    were used to visualize AHL-mediated communication in mixed biofilms, which were cultivated either in artificial flow chambers or in alginate beads in mouse lung tissue. In both model systems B. cepacia was capable of perceiving the AHL signals produced by P. aeruginosa, while the latter strain did...... not respond to the molecules produced by B. cepacia. Measurements of extracellular proteolytic activities of defined quorum-sensing mutants grown in media complemented with AHL extracts prepared from culture supernatants of various wild-type and mutant strains supported the view of unidirectional signalling...

  3. Effect of ceftazidime of formation of biofilm of Pseudomonas aeruginosa and mechanism%头孢他啶对铜绿假单胞菌生物膜形成的影响与机制的探讨

    Institute of Scientific and Technical Information of China (English)

    李琬琛; 宋林; 李立艳; 孙续国; 魏爱琳; 魏殿军

    2016-01-01

    目的 探讨头孢他啶在铜绿假单胞菌(PAE)生物膜形成过程中的抑制 、清除作用与机制,更好的指导临床用药.方法 通过96孔板结晶紫染色方法,定量分析头孢他啶对PAE标准菌株生物膜的抑制 、清除作用,通过real time-PCR方法对生物膜形成相关基因的表达进行相对定量分析,探讨头孢他啶对PAE生物膜的作用机制.结果 未形成成熟生物膜时,头孢他啶对PAE生长的抑制效果较好,而在有成熟生物膜形成时,头孢他啶不能有效抑制PAE的生长;头孢他啶与PAE生物膜形成相关基因的增多表达相关.结论 头孢他啶能够促进PAE生物膜形成相关基因的表达,临床对慢性PAE感染患者的治疗应避免使用头孢他啶.%OBJECTIVE To observe the effect of ceftazidime on inhibition of formation and clearance of Pseudomonas aeruginosa biofilm and analyze the mechanisms so as to provide guidance for clinical use of antibiotics .METHODS The 96 well plate crystal violet staining method was used to quantitatively analyze the effect of ceftazidime on inhi-bition and clearance of the P .aeruginosa biofilm ,and the real-time PCR method was employed to perform the rela-tive quantitative analysis of the expression of biofilm formation-related genes so as to observe the effect of ceftazi-dime on the formation of P .aeruginosa biofilm .RESULTS Ceftazidime had better effect on inhibition of growth of P .aeruginosa when the mature biofilms were not formed ,however ,ceftazidime could not effectively inhibit the growth of P .aeruginosa when the mature biofilms were formed .Ceftazidime was associated with the increased ex-pression of the biofilm formation-related genes of P .aeruginosa .CONCLUSION Ceftazidime can promote the ex-pression of the biofilm formation-related genes of P .aeruginosa .It is necessary for the hospital to avoid the use of ceftazidime for the treatment of the patients with chronic P .aeruginosa infection .

  4. Phenotypes of non-attached Pseudomonas aeruginosa aggregates resemble surface attached biofilm.

    Directory of Open Access Journals (Sweden)

    Morten Alhede

    Full Text Available For a chronic infection to be established, bacteria must be able to cope with hostile conditions such as low iron levels, oxidative stress, and clearance by the host defense, as well as antibiotic treatment. It is generally accepted that biofilm formation facilitates tolerance to these adverse 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 of age, both aggregates and flow-cell biofilm had the same slow growth rate as a stationary phase shaking cultures. Internal structures of the aggregates matrix components and their capacity to survive otherwise lethal treatments with antibiotics (referred to as tolerance and resistance to phagocytes were also found to be strikingly similar to flow-cell biofilms. Our data indicate that the tolerance of both biofilms and non-attached aggregates towards antibiotics is reversible by physical disruption. We provide evidence that the antibiotic tolerance is likely to be dependent on both 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 media; soft tissue fillers and non-healing wounds, and we propose that aggregated cells exhibit enhanced survival in the hostile host environment, compared with non

  5. Evolution of Ecological Diversity in Biofilms of Pseudomonas aeruginosa by Altered Cyclic Diguanylate Signaling

    Science.gov (United States)

    Flynn, Kenneth M.; Dowell, Gabrielle; Johnson, Thomas M.; Koestler, Benjamin J.; Waters, Christopher M.

    2016-01-01

    ABSTRACT The ecological and evolutionary forces that promote and maintain diversity in biofilms are not well understood. To quantify these forces, three Pseudomonas aeruginosa populations were experimentally evolved from strain PA14 in a daily cycle of attachment, assembly, and dispersal for 600 generations. Each biofilm population evolved diverse colony morphologies and mutator genotypes defective in DNA mismatch repair. This diversity enhanced population fitness and biofilm output, owing partly to rare, early colonizing mutants that enhanced attachment of others. Evolved mutants exhibited various levels of the intracellular signal cyclic-di-GMP, which associated with their timing of adherence. Manipulating cyclic-di-GMP levels within individual mutants revealed a network of interactions in the population that depended on various attachment strategies related to this signal. Diversification in biofilms may therefore arise and be reinforced by initial colonists that enable community assembly. IMPORTANCE How biofilm diversity assembles, evolves, and contributes to community function is largely unknown. This presents a major challenge for understanding evolution during chronic infections and during the growth of all surface-associated microbes. We used experimental evolution to probe these dynamics and found that diversity, partly related to altered cyclic-di-GMP levels, arose and persisted due to the emergence of ecological interdependencies related to attachment patterns. Clonal isolates failed to capture population attributes, which points to the need to account for diversity in infections. More broadly, this study offers an experimental framework for linking phenotypic variation to distinct ecological strategies in biofilms and for studying eco-evolutionary interactions. PMID:27021563

  6. Facultative control of matrix production optimizes competitive fitness in Pseudomonas aeruginosa PA14 biofilm models.

    Science.gov (United States)

    Madsen, Jonas S; Lin, Yu-Cheng; Squyres, Georgia R; Price-Whelan, Alexa; de Santiago Torio, Ana; Song, Angela; Cornell, William C; Sørensen, Søren J; Xavier, Joao B; Dietrich, Lars E P

    2015-12-01

    As biofilms grow, resident cells inevitably face the challenge of resource limitation. In the opportunistic pathogen Pseudomonas aeruginosa PA14, electron acceptor availability affects matrix production and, as a result, biofilm morphogenesis. The secreted matrix polysaccharide Pel is required for pellicle formation and for colony wrinkling, two activities that promote access to O2. We examined the exploitability and evolvability of Pel production at the air-liquid interface (during pellicle formation) and on solid surfaces (during colony formation). Although Pel contributes to the developmental response to electron acceptor limitation in both biofilm formation regimes, we found variation in the exploitability of its production and necessity for competitive fitness between the two systems. The wild type showed a competitive advantage against a non-Pel-producing mutant in pellicles but no advantage in colonies. Adaptation to the pellicle environment selected for mutants with a competitive advantage against the wild type in pellicles but also caused a severe disadvantage in colonies, even in wrinkled colony centers. Evolution in the colony center produced divergent phenotypes, while adaptation to the colony edge produced mutants with clear competitive advantages against the wild type in this O2-replete niche. In general, the structurally heterogeneous colony environment promoted more diversification than the more homogeneous pellicle. These results suggest that the role of Pel in community structure formation in response to electron acceptor limitation is unique to specific biofilm models and that the facultative control of Pel production is required for PA14 to maintain optimum benefit in different types of communities.

  7. Multivalency effects on Pseudomonas aeruginosa biofilm inhibition and dispersal by glycopeptide dendrimers targeting lectin LecA.

    Science.gov (United States)

    Bergmann, Myriam; Michaud, Gaëlle; Visini, Ricardo; Jin, Xian; Gillon, Emilie; Stocker, Achim; Imberty, Anne; Darbre, Tamis; Reymond, Jean-Louis

    2016-01-01

    The galactose specific lectin LecA partly mediates the formation of antibiotic resistant biofilms by Pseudomonas aeruginosa, an opportunistic pathogen causing lethal airways infections in immunocompromised and cystic fibrosis patients, suggesting that preventing LecA binding to natural saccharides might provide new opportunities for treatment. Here 8-fold (G3) and 16-fold (G4) galactosylated analogs of GalAG2, a tetravalent G2 glycopeptide dendrimer LecA ligand and P. aeruginosa biofilm inhibitor, were obtained by convergent chloroacetyl thioether (ClAc) ligation between 4-fold or 8-fold chloroacetylated dendrimer cores and digalactosylated dendritic arms. Hemagglutination inhibition, isothermal titration calorimetry and biofilm inhibition assays showed that G3 dendrimers bind LecA slightly better than their parent G2 dendrimers and induce complete biofilm inhibition and dispersal of P. aeruginosa biofilms, while G4 dendrimers show reduced binding and no biofilm inhibition. A binding model accounting for the observed saturation of glycopeptide dendrimer galactosyl groups and LecA binding sites is proposed based on the crystal structure of a G3 dendrimer LecA complex.

  8. A phytoanticipin derivative, sodium houttuyfonate, induces in vitro synergistic effects with levofloxacin against biofilm formation by Pseudomonas aeruginosa.

    Science.gov (United States)

    Shao, Jing; Cheng, Huijuan; Wang, Changzhong; Wang, Yan

    2012-01-01

    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. PMID:22996347

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

    Directory of Open Access Journals (Sweden)

    Jing Shao

    2012-09-01

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

  10. Detection of bacteria bearing resistant biofilm forms, by using the universal and specific PCR is still unhelpful in the diagnosis of periprosthetic joint infections(PJI.

    Directory of Open Access Journals (Sweden)

    Batool eZegaer

    2014-09-01

    Full Text Available Intraoperative conventional bacteriological cultures were compared with different polymerase chain reaction (PCR methods in patients with total joint arthroplasties. The isolated bacteria were investigated for biofilm formation, and the biofilm forming strains, in their planktonic and biofilm forms, were further tested for their antimicrobial resistance against several clinically important antimicrobials. Forty four bone and joint samples were included and classified as infected or non-infected according to standard criteria for periprosthetic hip and knee infections. For the bacteriological diagnosis, conventional culture, two types of universal PCR and species specific PCR for three selected pathogens (S. aureus, S. epidermidis, P. aeruginosa were applied. Biofilm formation determination was performed by the tissue culture plate method. Antimicrobial susceptibility of the planktonic bacteria was performed by the minimal inhibitory concentration determination and, of the biofilm forms, by the minimal inhibitory concentration for bacterial regrowth from the biofilm. Twenty samples were culture positive, with S. epidermidis, S. aureus or P. aeruginosa. All PCR methods were very ineffective in detecting only one pathogen. All isolates were biofilm positive and their biofilm forms, were highly resistant. In this study, compared to PCR, culture remains the gold standard. The biofilm formation by the causative bacteria and the concomitant manifold increased antimicrobial resistance may explain the clinical failure of treatment in some cases and should be considered in the future for therapeutic planning.

  11. The MerR-like regulator BrlR confers biofilm tolerance by activating multidrug efflux pumps in Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Liao, Julie; Schurr, Michael J; Sauer, Karin

    2013-08-01

    A defining characteristic of biofilms is antibiotic tolerance that can be up to 1,000-fold greater than that of planktonic cells. In Pseudomonas aeruginosa, biofilm tolerance to antimicrobial agents requires the biofilm-specific MerR-type transcriptional regulator BrlR. However, the mechanism by which BrlR mediates biofilm tolerance has not been elucidated. Genome-wide transcriptional profiling indicated that brlR was required for maximal expression of genes associated with antibiotic resistance, in particular those encoding the multidrug efflux pumps MexAB-OprM and MexEF-OprN. Chromatin immunoprecipitation (ChIP) analysis revealed a direct regulation of these genes by BrlR, with DNA binding assays confirming BrlR binding to the promoter regions of the mexAB-oprM and mexEF-oprN operons. Quantitative reverse transcriptase PCR (qRT-PCR) analysis further indicated BrlR to be an activator of mexAB-oprM and mexEF-oprN gene expression. Moreover, immunoblot analysis confirmed increased MexA abundance in cells overexpressing brlR. Inactivation of both efflux pumps rendered biofilms significantly more susceptible to five different classes of antibiotics by affecting MIC but not the recalcitrance of biofilms to killing by bactericidal agents. Overexpression of either efflux pump in a ΔbrlR strain partly restored tolerance of ΔbrlR biofilms to antibiotics. Expression of brlR in mutant biofilms lacking both efflux pumps partly restored antimicrobial tolerance of biofilms to wild-type levels. Our results indicate that BrlR acts as an activator of multidrug efflux pumps to confer tolerance to P. aeruginosa biofilms and to resist the action of antimicrobial agents.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  14. Synergistic Activities of an Efflux Pump Inhibitor and Iron Chelators against Pseudomonas aeruginosa Growth and Biofilm Formation

    DEFF Research Database (Denmark)

    Liu, Yang; Yang, Liang; Molin, Søren

    2010-01-01

    The efflux pump inhibitor phenyl-arginine-beta-naphthylamide (PA beta N) was paired with iron chelators 2,2'-dipyridyl, acetohydroxamic acid, and EDTA to assess synergistic activities against Pseudomonas aeruginosa growth and biofilm formation. All of the tested iron chelators synergistically...

  15. Formation of hydroxyl radicals contributes to the bactericidal activity of ciprofloxacin against Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Jensen, Peter Ø.; Briales, Alejandra; Brochmann, Rikke Prejh;

    2014-01-01

    induction of cytotoxic hydroxyl radicals (OH˙) during antibiotic treatment of planktonically grown cells may contribute to action of the commonly used antibiotic ciprofloxacin on P. aeruginosa biofilms. For this purpose, WT PAO1, a catalase deficient ΔkatA and a ciprofloxacin resistant mutant of PAO1 (gyr...

  16. The biofilm-specific antibiotic resistance gene ndvB is important for expression of ethanol oxidation genes in Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Beaudoin, Trevor; Zhang, Li; Hinz, Aaron J; Parr, Christopher J; Mah, Thien-Fah

    2012-06-01

    Bacteria growing in biofilms are responsible for a large number of persistent infections and are often more resistant to antibiotics than are free-floating bacteria. In a previous study, we identified a Pseudomonas aeruginosa gene, ndvB, which is important for the formation of periplasmic glucans. We established that these glucans function in biofilm-specific antibiotic resistance by sequestering antibiotic molecules away from their cellular targets. In this study, we investigate another function of ndvB in biofilm-specific antibiotic resistance. DNA microarray analysis identified 24 genes that were responsive to the presence of ndvB. A subset of 20 genes, including 8 ethanol oxidation genes (ercS', erbR, exaA, exaB, eraR, pqqB, pqqC, and pqqE), was highly expressed in wild-type biofilm cells but not in ΔndvB biofilms, while 4 genes displayed the reciprocal expression pattern. Using quantitative real-time PCR, we confirmed the ndvB-dependent expression of the ethanol oxidation genes and additionally demonstrated that these genes were more highly expressed in biofilms than in planktonic cultures. Expression of erbR in ΔndvB biofilms was restored after the treatment of the biofilm with periplasmic extracts derived from wild-type biofilm cells. Inactivation of ethanol oxidation genes increased the sensitivity of biofilms to tobramycin. Together, these results reveal that ndvB affects the expression of multiple genes in biofilms and that ethanol oxidation genes are linked to biofilm-specific antibiotic resistance.

  17. Effects of crude plant extracts of Senecio calvus on biofilm formation of Pseudomonas aeruginosa and Escherichia coli

    Directory of Open Access Journals (Sweden)

    Christian FLORIAN-CARRILLO

    2015-06-01

    Full Text Available Senecio calvus, a traditional medicinal plant native of Peruvian Andes was used to evaluate its activity against biofilm formation. Crude extracts were tested against cultures of Pseudomonas aeruginosa and Escherichia coli, two bacteria that use different signals of QS. Briefly, cultures in growth phase were mixed with crude extracts of aerial parts of S. calvus to determine the degree of inhibition of biofilms, subinhibitory concentrations were used where corresponded as previously established by a minimum inhibitory concentration test (MIC by microtitration method. Results indicate a mean inhibition of 92.9% and 76.4% in two of the extracts for Pseudomonas aeruginosa and 55.5% as maximum mean inhibition percentage for Escherichia coli which indicates that Senecio calvus is a candidate for isolation of inhibitory molecules of biofilms.

  18. Rhamnolipid but not motility is associated with the initiation of biofilm seeding dispersal of Pseudomonas aeruginosa strain PA17

    Indian Academy of Sciences (India)

    Jingjing Wang; Bing Yu; Deying Tian; Ming Ni

    2013-03-01

    Seeding dispersal is an active detachment exhibit in aging Pseudomonas aeruginosa biofilm. Yet, effect factors of this process in the biofilm of clinical isolated mucoid P. aeruginosa strain remain to be better characterized. In our previous work, one mucoid P. earuginosa strain PA17 was isolated from a patient with recurrent pulmonary infection. In this study, confocal scanning laser microscope combined with LIVE/DEAD viability staining revealed that PA17 biofilm exhibited earlier seeding dispersal than non-mucoid PAO1. We further compared the motility and the expression of motility-associated gene during biofilm development between PA17 and PAO1. PA17 was found to be impaired in all three kinds of motility compared to PAO1. Moreover, we investigated the expression of rhamnolipid-associated genes in PA17 and PAO1 biofilm. The expression of these genes was in accordance with the process of seeding dispersal. Our results indicated that rhamnolipid but not motility is associated with the initiation of seeding dispersal of PA17 biofilm.

  19. A Microfluidic Approach to Investigating a Synergistic Effect of Tobramycin and Sodium Dodecyl Sulfate on Pseudomonas aeruginosa Biofilms.

    Science.gov (United States)

    Shin, Soojeong; Ahmed, Ishtiaq; Hwang, Jangsun; Seo, Youngmin; Lee, Eunwon; Choi, Jonghoon; Moon, Sangjun; Hong, Jong Wook

    2016-01-01

    In recent years, a microfluidic technology has contributed a significant role in biological research, specifically for the study of biofilms. Bacterial biofilms are a source of infections and contamination in the environment due to an extra polymeric matrix. Inadequate uses of antibiotics make the bacterial biofilms antibiotic resistant. Therefore, it is important to determine the effective concentration of antibiotics in order to eliminate bacterial biofilms. The present microfluidic study was carried out to analyze the activities of tobramycin and sodium dodecyl sulfate (SDS) against Pseudomonas aeruginosa biofilms with a continuous flow in order to achieve a greater delivery of the agents. The results show that a co-treatment of tobramycin and SDS significantly reduced the biomass of biofilms (by more than 99%) after 24 h. Tobramycin and SDS killed and detached bacteria in the cores of biofilms. Evidently, our data suggest that a microchannel would be effective for both quantitative and qualitative evaluations in order to test combinatorial effect of drugs and chemicals on a complexed biological system including biofilm.

  20. C-di-GMP regulates Pseudomonas aeruginosa stress response to tellurite during both planktonic and biofilm modes of growth.

    Science.gov (United States)

    Chua, Song Lin; Sivakumar, Krishnakumar; Rybtke, Morten; Yuan, Mingjun; Andersen, Jens Bo; Nielsen, Thomas E; Givskov, Michael; Tolker-Nielsen, Tim; Cao, Bin; Kjelleberg, Staffan; Yang, Liang

    2015-01-01

    Stress response plays an important role on microbial adaptation under hostile environmental conditions. It is generally unclear how the signaling transduction pathway mediates a stress response in planktonic and biofilm modes of microbial communities simultaneously. Here, we showed that metalloid tellurite (TeO3(2-)) exposure induced the intracellular content of the secondary messenger cyclic di-GMP (c-di-GMP) of Pseudomonas aeruginosa. Two diguanylate cyclases (DGCs), SadC and SiaD, were responsible for the increased intracellular content of c-di-GMP. Enhanced c-di-GMP levels by TeO3(2-) further increased P. aeruginosa biofilm formation and resistance to TeO3(2-). P. aeruginosa ΔsadCΔsiaD and PAO1/p(lac)-yhjH mutants with low intracellular c-di-GMP content were more sensitive to TeO3(2-) exposure and had low relative fitness compared to the wild-type PAO1 planktonic and biofilm cultures exposed to TeO3(2-). Our study provided evidence that c-di-GMP level can play an important role in mediating stress response in microbial communities during both planktonic and biofilm modes of growth.

  1. Biofilm formation by Staphylococcus epidermidis on peritoneal dialysis catheters and the effects of extracellular products from Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Pihl, Maria; Arvidsson, Anna; Skepö, Marie;

    2013-01-01

    Biofilm formation by Staphylococcus epidermidis is a cause of infections related to peritoneal dialysis (PD). We have used a PD catheter flow-cell model in combination with confocal scanning laser microscopy and atomic force microscopy to study biofilm formation by S. epidermidis. Adherence...... to serum-coated catheters was four times greater than to uncoated ones, suggesting that S. epidermidis binds to serum proteins on the catheter surface. Pseudomonas aeruginosa biofilm supernatant interfered with the formation of a serum protein coat thereby reducing the capacity for biofilm formation in S. epidermidis....... Supernatants from ΔpelA, ΔpslBCD and ΔrhlAB strains of P. aeruginosa showed no differences from the wild-type supernatant indicating that the effect on serum coat formation was not due to rhamnolipids or the PelA and PslBCD polysaccharides. Supernatant from P. aeruginosa also dispersed established S. epidermidis...

  2. Biofilms and Cyclic di-GMP (c-di-GMP) Signaling: Lessons from Pseudomonas aeruginosa and Other Bacteria.

    Science.gov (United States)

    Valentini, Martina; Filloux, Alain

    2016-06-10

    The cyclic di-GMP (c-di-GMP) second messenger represents a signaling system that regulates many bacterial behaviors and is of key importance for driving the lifestyle switch between motile loner cells and biofilm formers. This review provides an up-to-date compendium of c-di-GMP pathways connected to biofilm formation, biofilm-associated motilities, and other functionalities in the ubiquitous and opportunistic human pathogen Pseudomonas aeruginosa This bacterium is frequently adopted as a model organism to study bacterial biofilm formation. Importantly, its versatility and adaptation capabilities are linked with a broad range of complex regulatory networks, including a large set of genes involved in c-di-GMP biosynthesis, degradation, and transmission.

  3. High beta-Lactamase Levels Change the Pharmacodynamics of beta-Lactam Antibiotics in Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Wang, Hengzhuang; Ciofu, Oana; Yang, Liang;

    2013-01-01

    Resistance to beta-lactam antibiotics is a frequent problem in Pseudomonas aeruginosa lung infection of cystic fibrosis (CF) patients. This resistance is mainly due to the hyperproduction of chromosomally encoded beta-lactamase and biofilm formation. The purpose of this study was to investigate......, microtiter plates, and on alginate beads were treated with different concentrations of ceftazidime and imipenem. The kinetics of antibiotics on the biofilms was investigated in vitro by time-kill methods. Time-dependent killing of ceftazidime was observed in PAO1 biofilms, but concentration-dependent killing......-lactamase, which can hydrolyze the beta-lactam antibiotics. The PK/PD indices of the AUC/MBIC and C-max/MBIC (AUC is the area under concentration-time curve, MBIC is the minimal biofilm-inhibitory concentration, and C-max is the maximum concentration of drug in serum) are probably the best parameters to describe...

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

    Science.gov (United States)

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

    2013-01-01

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

  5. 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.

  6. Macrolides decrease the minimal inhibitory concentration of anti-pseudomonal agents against Pseudomonas aeruginosa from cystic fibrosis patients in biofilm

    Directory of Open Access Journals (Sweden)

    Lutz Larissa

    2012-09-01

    Full Text Available Abstract Background Biofilm production is an important mechanism for bacterial survival and its association with antimicrobial resistance represents a challenge for the patient treatment. In this study we evaluated the in vitro action of macrolides in combination with anti-pseudomonal agents on biofilm-grown Pseudomonas aeruginosa recovered from cystic fibrosis (CF patients. Results A total of 64 isolates were analysed. The biofilm inhibitory concentration (BIC results were consistently higher than those obtained by the conventional method, minimal inhibitory concentration, (MIC for most anti-pseudomonal agents tested (ceftazidime: P = 0.001, tobramycin: P = 0.001, imipenem: P P = 0.005. When macrolides were associated with the anti-pseudomonal agents, the BIC values were reduced significantly for ceftazidime (P  0.001 and tobramycin (P  0.001, regardless the concentration of macrolides. Strong inhibitory quotient was observed when azithromycin at 8 mg/L was associated with all anti-pseudomonal agents tested in biofilm conditions. Conclusions P. aeruginosa from CF patients within biofilms are highly resistant to antibiotics but macrolides proved to augment the in vitro activity of anti-pseudomonal agents.

  7. Synergistic antibiofilm efficacy of various commercial antiseptics, enzymes and EDTA: a study of Pseudomonas aeruginosa and Staphylococcus aureus biofilms.

    Science.gov (United States)

    Lefebvre, Elodie; Vighetto, Christophe; Di Martino, Patrick; Larreta Garde, Véronique; Seyer, Damien

    2016-08-01

    A multistep strategy was used to generate a combined antibiofilm treatment that could efficiently decrease the biomass of dense biofilms (≥6 × 10(7) CFU/cm(2)). Several compounds that exhibited activity against various targets were tested individually and in combination to search for possible synergistic effects. First, the antibiofilm activity of various commercially available antiseptics was tested on Pseudomonas aeruginosa and Staphylococcus aureus. Second, antiseptics were mixed with ethylene diamine tetra-acetic acid (EDTA), which is an ion chelator that can disturb biofilm organisation, and additive effects on biofilm biomass degradation were found for both strains. Then, enzymes with the ability to destabilise the biofilm matrix by hydrolysing either its proteins or its polysaccharides were used; as expected, they did not decrease bacterial viability but were revealed as efficient biomass reducers. The combination of antiseptics, EDTA and proteases, all at low concentrations, revealed a synergistic effect leading to total eradication of dense biofilms both of P. aeruginosa and S. aureus. PMID:27424598

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

    OpenAIRE

    Danila Soares Caixeta; Thiago Henrique Scarpa; Danilo Florisvaldo Brugnera; Dieyckson Osvani Freire; Eduardo Alves; Luiz Ronaldo de Abreu; Roberta Hilsdorf Piccoli

    2012-01-01

    The biofilm formation of Pseudomonas aeruginosa and Pseudomonas fluorescens on AISI 304 stainless steel in the presence of reconstituted skim milk under different temperatures was conducted, and the potential of three chemical sanitizers in removing the mono-species biofilms formed was compared. Pseudomonas aeruginosa cultivated in skim milk at 28 °C presented better growth rate (10.4 log CFU.mL-1) when compared with 3.7 and 4.2 log CFU.mL-1 for P. aeruginosa and P. fluorescens cultivated at ...

  9. D-amino acids enhance the activity of antimicrobials against biofilms of clinical wound isolates of Staphylococcus aureus and Pseudomonas aeruginosa.

    Science.gov (United States)

    Sanchez, Carlos J; Akers, Kevin S; Romano, Desiree R; Woodbury, Ronald L; Hardy, Sharanda K; Murray, Clinton K; Wenke, Joseph C

    2014-08-01

    Within wounds, microorganisms predominantly exist as biofilms. Biofilms are associated with chronic infections and represent a tremendous clinical challenge. As antibiotics are often ineffective against biofilms, use of dispersal agents as adjunctive, topical therapies for the treatment of wound infections involving biofilms has gained interest. We evaluated in vitro the dispersive activity of D-amino acids (D-AAs) on biofilms from clinical wound isolates of Staphylococcus aureus and Pseudomonas aeruginosa; moreover, we determined whether combinations of D-AAs and antibiotics (clindamycin, cefazolin, oxacillin, rifampin, and vancomycin for S. aureus and amikacin, colistin, ciprofloxacin, imipenem, and ceftazidime for P. aeruginosa) enhance activity against biofilms. D-Met, D-Phe, and D-Trp at concentrations of ≥ 5 mM effectively dispersed preformed biofilms of S. aureus and P. aeruginosa clinical isolates, an effect that was enhanced when they were combined as an equimolar mixture (D-Met/D-Phe/D-Trp). When combined with D-AAs, the activity of rifampin was significantly enhanced against biofilms of clinical isolates of S. aureus, as indicated by a reduction in the minimum biofilm inhibitory concentration (MBIC) (from 32 to 8 μg/ml) and a >2-log reduction of viable biofilm bacteria compared to treatment with antibiotic alone. The addition of D-AAs was also observed to enhance the activity of colistin and ciprofloxacin against biofilms of P. aeruginosa, reducing the observed MBIC and the number of viable bacteria by >2 logs and 1 log at 64 and 32 μg/ml in contrast to antibiotics alone. These findings indicate that the biofilm dispersal activity of D-AAs may represent an effective strategy, in combination with antimicrobials, to release bacteria from biofilms, subsequently enhancing antimicrobial activity.

  10. 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. PMID:24268182

  11. Assessment of the working range and effect of sodium dichloroisocyanurate on Pseudomonas aeruginosa biofilms and planktonic cells.

    Science.gov (United States)

    Morgenthau, Ari; Nicolae, Alexandru M; Laursen, Andrew E; Foucher, Daniel A; Wolfaardt, Gideon M; Hausner, Martina

    2012-01-01

    Sodium dichloroisocyanurate (NaDCC) is a chemical agent that acts against microorganisms in a manner similar to that of sodium hypochlorite by releasing free available chlorine. NaDCC has been approved by the WHO for the emergency treatment of water and by the US EPA for routine treatment of water. Previous studies assessing the effectiveness of NaDCC for the treatment of water implied that NaDCC should have a wide array of disinfecting effects beyond the treatment of planktonic cells in potable water. In this study the biocidal effects of NaDCC against Pseudomonas aeruginosa cells in different growth modes including planktonic cells and biofilms were explored. The data showed that a 60% dilution of the standard NaDCC solution was effective in the treatment of both P. aeruginosa planktonic cells and biofilms.

  12. Assessment of the working range and effect of sodium dichloroisocyanurate on Pseudomonas aeruginosa biofilms and planktonic cells.

    Science.gov (United States)

    Morgenthau, Ari; Nicolae, Alexandru M; Laursen, Andrew E; Foucher, Daniel A; Wolfaardt, Gideon M; Hausner, Martina

    2012-01-01

    Sodium dichloroisocyanurate (NaDCC) is a chemical agent that acts against microorganisms in a manner similar to that of sodium hypochlorite by releasing free available chlorine. NaDCC has been approved by the WHO for the emergency treatment of water and by the US EPA for routine treatment of water. Previous studies assessing the effectiveness of NaDCC for the treatment of water implied that NaDCC should have a wide array of disinfecting effects beyond the treatment of planktonic cells in potable water. In this study the biocidal effects of NaDCC against Pseudomonas aeruginosa cells in different growth modes including planktonic cells and biofilms were explored. The data showed that a 60% dilution of the standard NaDCC solution was effective in the treatment of both P. aeruginosa planktonic cells and biofilms. PMID:22263660

  13. A novel technique using potassium permanganate and reflectance confocal microscopy to image biofilm extracellular polymeric matrix reveals non-eDNA networks in Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Swearingen, Matthew C; Mehta, Ajeet; Mehta, Amar; Nistico, Laura; Hill, Preston J; Falzarano, Anthony R; Wozniak, Daniel J; Hall-Stoodley, Luanne; Stoodley, Paul

    2016-02-01

    Biofilms are etiologically important in the development of chronic medical and dental infections. The biofilm extracellular polymeric substance (EPS) determines biofilm structure and allows bacteria in biofilms to adapt to changes in mechanical loads such as fluid shear. However, EPS components are difficult to visualize microscopically because of their low density and molecular complexity. Here, we tested potassium permanganate, KMnO4, for use as a non-specific EPS contrast-enhancing stain using confocal laser scanning microscopy in reflectance mode. We demonstrate that KMnO4 reacted with EPS components of various strains of Pseudomonas, Staphylococcus and Streptococcus, yielding brown MnO2 precipitate deposition on the EPS, which was quantifiable using data from the laser reflection detector. Furthermore, the MnO2 signal could be quantified in combination with fluorescent nucleic acid staining. COMSTAT image analysis indicated that KMnO4 staining increased the estimated biovolume over that determined by nucleic acid staining alone for all strains tested, and revealed non-eDNA EPS networks in Pseudomonas aeruginosa biofilm. In vitro and in vivo testing indicated that KMnO4 reacted with poly-N-acetylglucosamine and Pseudomonas Pel polysaccharide, but did not react strongly with DNA or alginate. KMnO4 staining may have application as a research tool and for diagnostic potential for biofilms in clinical samples.

  14. A novel technique using potassium permanganate and reflectance confocal microscopy to image biofilm extracellular polymeric matrix reveals non-eDNA networks in Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Swearingen, Matthew C; Mehta, Ajeet; Mehta, Amar; Nistico, Laura; Hill, Preston J; Falzarano, Anthony R; Wozniak, Daniel J; Hall-Stoodley, Luanne; Stoodley, Paul

    2016-02-01

    Biofilms are etiologically important in the development of chronic medical and dental infections. The biofilm extracellular polymeric substance (EPS) determines biofilm structure and allows bacteria in biofilms to adapt to changes in mechanical loads such as fluid shear. However, EPS components are difficult to visualize microscopically because of their low density and molecular complexity. Here, we tested potassium permanganate, KMnO4, for use as a non-specific EPS contrast-enhancing stain using confocal laser scanning microscopy in reflectance mode. We demonstrate that KMnO4 reacted with EPS components of various strains of Pseudomonas, Staphylococcus and Streptococcus, yielding brown MnO2 precipitate deposition on the EPS, which was quantifiable using data from the laser reflection detector. Furthermore, the MnO2 signal could be quantified in combination with fluorescent nucleic acid staining. COMSTAT image analysis indicated that KMnO4 staining increased the estimated biovolume over that determined by nucleic acid staining alone for all strains tested, and revealed non-eDNA EPS networks in Pseudomonas aeruginosa biofilm. In vitro and in vivo testing indicated that KMnO4 reacted with poly-N-acetylglucosamine and Pseudomonas Pel polysaccharide, but did not react strongly with DNA or alginate. KMnO4 staining may have application as a research tool and for diagnostic potential for biofilms in clinical samples. PMID:26536894

  15. C-di-GMP regulates Pseudomonas aeruginosa stress response to tellurite during both planktonic and biofilm modes of growth

    DEFF Research Database (Denmark)

    Chua, Song Lin; Sivakumar, Krishnakumar; Rybtke, Morten Levin;

    2015-01-01

    tellurite (TeO3(2-)) exposure induced the intracellular content of the secondary messenger cyclic di-GMP (c-di-GMP) of Pseudomonas aeruginosa. Two diguanylate cyclases (DGCs), SadC and SiaD, were responsible for the increased intracellular content of c-di-GMP. Enhanced c-di-GMP levels by TeO3(2-) further...... increased P. aeruginosa biofilm formation and resistance to TeO3(2-). P. aeruginosa ΔsadCΔsiaD and PAO1/p(lac)-yhjH mutants with low intracellular c-di-GMP content were more sensitive to TeO3(2-) exposure and had low relative fitness compared to the wild-type PAO1 planktonic and biofilm cultures exposed...... to TeO3(2-). Our study provided evidence that c-di-GMP level can play an important role in mediating stress response in microbial communities during both planktonic and biofilm modes of growth....

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

    Science.gov (United States)

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

    2014-03-01

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

  17. Structural and Biochemical Analysis of Tyrosine Phosphatase Related to Biofilm Formation A (TpbA) from the Opportunistic Pathogen Pseudomonas aeruginosa PAO1

    OpenAIRE

    Kun Xu; Shanshan Li; Wen Yang; Kan Li; Yuwei Bai; Yueyang Xu; Jin Jin; Yingying Wang; Mark Bartlam

    2015-01-01

    Biofilms are important for cell communication and growth in most bacteria, and are responsible for a number of human clinical infections and diseases. TpbA (PA3885) is a dual specific tyrosine phosphatase (DUSP) that negatively regulates biofilm formation in the opportunistic pathogen Pseudomonas aeruginosa PAO1 by converting extracellular quorum sensing signals into internal gene cascade reactions that result in reduced biofilm formation. We have determined the three-dimensional crystal stru...

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

    Directory of Open Access Journals (Sweden)

    Annie I Chen

    2014-10-01

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

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

    Directory of Open Access Journals (Sweden)

    Danila Soares Caixeta

    2012-03-01

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

  20. EFFECT OF ULTRASOUND RADIATION ON FORMED BIOFILMS AND ABILITY TO THEIR FORMATION IN S.AUREUS

    OpenAIRE

    Mishina M.M.

    2013-01-01

    Microbiological research of the clinical material receivedfrom with inflammatory processes was carried on that todetect ability to form biofilms and to study effect of low-intensity ultrasound radiation on formed biofilms and theiraggregation ability. Performed research showed that ultrasound radiation of low intensity could destroy biofilms and inhibit ability of microorganisms to form secondary biofilms.

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

    Directory of Open Access Journals (Sweden)

    ahya abdi ali

    2015-02-01

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

  2. Facultative control of matrix production optimizes competitive fitness in Pseudomonas aeruginosa PA14 biofilm models

    DEFF Research Database (Denmark)

    Madsen, Jonas Stenløkke; Lin, Yu Cheng; Squyres, Georgia R.;

    2015-01-01

    to the colony edge produced mutants with clear competitive advantages against the wild type in this O2-replete niche. In general, the structurally heterogeneous colony environment promoted more diversification than the more homogeneous pellicle. These results suggest that the role of Pel in community structure......As biofilms grow, resident cells inevitably face the challenge of resource limitation. In the opportunistic pathogen Pseudomonas aeruginosa PA14, electron acceptor availability affects matrix production and, as a result, biofilm morphogenesis. The secreted matrix polysaccharide Pel is required...... response to electron acceptor limitation in both biofilm formation regimes, we found variation in the exploitability of its production and necessity for competitive fitness between the two systems. The wild type showed a competitive advantage against a non-Pel-producing mutant in pellicles but no advantage...

  3. Synergistic antibacterial efficacy of early combination treatment with tobramycin and quorum-sensing inhibitors against Pseudomonas aeruginosa in an intraperitoneal foreign-body infection mouse model

    DEFF Research Database (Denmark)

    Christensen, Louise; van Gennip, Maria; Jakobsen, Tim H;

    2012-01-01

    Quorum sensing (QS)-deficient Pseudomonas aeruginosa biofilms formed in vitro are more susceptible to tobramycin than QS-proficient P. aeruginosa biofilms, and combination treatment with a QS inhibitor (QSI) and tobramycin shows synergistic effects on the killing of in vitro biofilms. We extended...

  4. The lipopeptide 6-2 produced by Bacillus amyloliquefaciens anti-CA has potent activity against the biofilm-forming organisms.

    Science.gov (United States)

    Song, Bo; Wang, Yu-Zhen; Wang, Guang-Yuan; Liu, Guang-Lei; Li, Wan-Zhong; Yan, Fang

    2016-07-15

    Both the whole cells and protoplasts of Pseudomonas aeruginosa PAO1 and Bacillus cereus, two biofilm-forming bacteria, were disrupted by the lipopeptide 6-2 produced by Bacillus amyloliquefaciens anti-CA. The lipopeptide 6-2 could also effectively inhibit the formation of biofilms and disperse pre-formed biofilms. Live/dead staining of the biofilms grown in the absence or presence of the lipopeptide 6-2 showed that more dead bacterial cells in the presence of the lipopeptide than those in the absence of the lipopeptide and biofilm formation was greatly reduced by the lipopeptide 6-2. Expression of the PslC gene related to exopolysaccharides in P. aeruginosa PAO1 was also inhibited. All these results demonstrated that the lipopeptide 6-2 produced by B. amyloliquefaciens anti-CA had a high activity against biofilm-forming bacteria. The lipopeptide 6-2 also killed the larvae of Balanus amphitrite and inhibit the germination of Laminaria japonica spore and growth of protozoa, all of which were the fouling organisms in marine environments. PMID:27184127

  5. Effect of Cinnamomum burmannii Nees ex Bl. and Massoia aromatica Becc. Essential Oils on Planktonic Growth and Biofilm formation of Pseudomonas aeruginosa and Staphylococcus aureus In Vitro

    Directory of Open Access Journals (Sweden)

    Sylvia Utami Tunjung Pratiwi

    2015-03-01

    Full Text Available Summary. Biofilms are communities of microorganisms that can be found in almost every habitat. They can be attached to a surface and protected by an extracellular matrix of biomolecules that substantially protect microorganisms from environmental effects. The aim of this research is to explore the potency of essential oils from Cinnamomum burmannii Nees ex Bl. and Massoia aromatica Becc. against planktonic growth and biofilm formation of, two opportunistic pathogens, Pseudomonas aeruginosa PAO1 and Staphylococcus aureus Cowan I. Essential oil from C. burmannii  and M. aromatica showed a 50% inhibition of  P. aeruginosa and S. aureus planktonic growth (PMIC50 at concentration of 0.12 % v/v. Essential oil from C. burmannii and M.  aromatica showed capability to inhibit 50% (MBIC50 of P. aeruginosa and S. aureus biofilm formation at concentration of 0.03 % v/v, whereas higher concentration (0.12 % v/v was needed by C. burmannii and M. aromatica oil to disrupt 50% of P. aeruginosa and S. aureus established biofilm. The analysis by GC-MS showed cinnamic aldehyde (92.02 % to be the major component of C. burmannii essential oil, whereas Massoialactone (92.05 % was the main constituent of M. aromatica essential oil. The results obtained in this study have made the oil of C. burmannii and M. aromatica oil as an interesting source for antibiofilm agents in the development of new strategies to treat infections caused by P. aeruginosa and  S. aureus biofilm.Industrial Relevance. Instead of freely swimming in solution (planktonic, in nature microbial tends to adhere to surfaces, and develop microbial biofilms. Microbial biofilms are exhibits resistance to both antimicrobial drugs and the host defence systems, which often results in persistent and difficult-to-treat infections. This makes the discovery of anti-infective agents which are active against planktonic and biofilm microbial represents an important goal. Plant is an interesting source for finding

  6. In vitro and in vivo generation and characterization of Pseudomonas aeruginosa biofilm-dispersed cells via c-di-GMP manipulation.

    Science.gov (United States)

    Chua, Song Lin; Hultqvist, Louise D; Yuan, Mingjun; Rybtke, Morten; Nielsen, Thomas E; Givskov, Michael; Tolker-Nielsen, Tim; Yang, Liang

    2015-08-01

    Bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a global secondary bacterial messenger that controls the formation of drug-resistant multicellular biofilms. Lowering the intracellular c-di-GMP content can disperse biofilms, and it is proposed as a biofilm eradication strategy. However, freshly dispersed biofilm cells exhibit a physiology distinct from biofilm and planktonic cells, and they might have a clinically relevant role in infections. Here we present in vitro and in vivo protocols for the generation and characterization of dispersed cells from Pseudomonas aeruginosa biofilms by reducing the intracellular c-di-GMP content through modulation of phosphodiesterases (PDEs). Unlike conventional protocols that demonstrate biofilm dispersal by biomass quantification, our protocols enable physiological characterization of the dispersed cells. Biomarkers of dispersed cells are identified and quantified, serving as potential targets for treating the dispersed cells. The in vitro protocol can be completed within 4 d, whereas the in vivo protocol requires 7 d.

  7. 黄芩苷对铜绿假单胞菌生物膜的影响%Effect of Baicalin on Pseudomonas Aeruginosa Biofilms

    Institute of Scientific and Technical Information of China (English)

    王贵年; 范莹; 王龙梓; 吴娟

    2011-01-01

    Objective To investigate the effect of baicalin on Pseudomonas aeruginosa biofilms in vitro. Methods Clinical isolates of Pseudomonas aeruginosa were cuhured in Luria - Bertani medium - aspirate sputum pipe system to establish biofilm formation. Biofilm was observed in AgNO3 staining. Viable bacterial counts were determined by serial dilution. MICs were measured by doubling dilution.Results The biofilm was inhibited and destructed by 15. 65mg/L of baicalin. Conclusion Baicalin displayed potent activity against Pseudomonas aeruginosa biofilms.%目的 研究黄芩苷对体外铜绿假单胞菌(pseudomonas aeruginosa,Pa)生物膜(biofilm,BF)的影响.方法 选取临床分离呼吸道Pa,采用LB肉汤-吸痰管系统培养BF,建立体外BF模型,银染法观察BF变化.将黄芩苷作用于BF,连续稀释法进行活菌计数,微量稀释法测定最低抑菌浓度(MIC).结果 15.65mg/L的黄芩苷即可抑制和破坏BF.结论 黄芩苷对体外铜绿假单胞菌生物膜有较强的抑制作用.

  8. Evaluation of antibiotic efficacy against infections caused by planktonic or biofilm cultures of Pseudomonas aeruginosa and Klebsiella pneumoniae in Galleria mellonella.

    Science.gov (United States)

    Benthall, Gabriel; Touzel, Rebecca E; Hind, Charlotte K; Titball, Richard W; Sutton, J Mark; Thomas, Rachael J; Wand, Matthew E

    2015-11-01

    The lack of novel antibiotics for more than a decade has placed increased pressure on existing therapies to combat the emergence of multidrug-resistant (MDR) bacterial pathogens. This study evaluated the Galleria mellonella insect model in determining the efficacy of available antibiotics against planktonic and biofilm infections of MDR Pseudomonas aeruginosa and Klebsiella pneumoniae strains in comparison with in vitro minimum inhibitory concentration (MIC) determination. In general, in vitro analysis agreed with the G. mellonella studies, and susceptibility in Galleria identified different drug resistance mechanisms. However, the carbapenems tested appeared to perform better in vivo than in vitro, with meropenem and imipenem able to clear K. pneumoniae and P. aeruginosa infections with strains that had bla(NDM-1) and bla(VIM) carbapenemases. This study also established an implant model in G. mellonella to allow testing of antibiotic efficacy against biofilm-derived infections. A reduction in antibiotic efficacy of amikacin against K. pneumoniae and P. aeruginosa biofilms was observed compared with a planktonic infection. Ciprofloxacin was found to be less effective at clearing a P. aeruginosa biofilm infection compared with a planktonic infection, but no statistical difference was seen between K. pneumoniae biofilm and planktonic infections treated with this antibiotic (P>0.05). This study provides important information regarding the suitability of Galleria as a model for antibiotic efficacy testing both against planktonic and biofilm-derived MDR infections.

  9. Evaluation of antibiotic efficacy against infections caused by planktonic or biofilm cultures of Pseudomonas aeruginosa and Klebsiella pneumoniae in Galleria mellonella.

    Science.gov (United States)

    Benthall, Gabriel; Touzel, Rebecca E; Hind, Charlotte K; Titball, Richard W; Sutton, J Mark; Thomas, Rachael J; Wand, Matthew E

    2015-11-01

    The lack of novel antibiotics for more than a decade has placed increased pressure on existing therapies to combat the emergence of multidrug-resistant (MDR) bacterial pathogens. This study evaluated the Galleria mellonella insect model in determining the efficacy of available antibiotics against planktonic and biofilm infections of MDR Pseudomonas aeruginosa and Klebsiella pneumoniae strains in comparison with in vitro minimum inhibitory concentration (MIC) determination. In general, in vitro analysis agreed with the G. mellonella studies, and susceptibility in Galleria identified different drug resistance mechanisms. However, the carbapenems tested appeared to perform better in vivo than in vitro, with meropenem and imipenem able to clear K. pneumoniae and P. aeruginosa infections with strains that had bla(NDM-1) and bla(VIM) carbapenemases. This study also established an implant model in G. mellonella to allow testing of antibiotic efficacy against biofilm-derived infections. A reduction in antibiotic efficacy of amikacin against K. pneumoniae and P. aeruginosa biofilms was observed compared with a planktonic infection. Ciprofloxacin was found to be less effective at clearing a P. aeruginosa biofilm infection compared with a planktonic infection, but no statistical difference was seen between K. pneumoniae biofilm and planktonic infections treated with this antibiotic (P>0.05). This study provides important information regarding the suitability of Galleria as a model for antibiotic efficacy testing both against planktonic and biofilm-derived MDR infections. PMID:26364845

  10. Confocal laser scanning microscopy for assessment of pseudomonas aeruginosa biofilm formation%激光共聚焦显微镜观察铜绿假单胞菌生物膜的形成

    Institute of Scientific and Technical Information of China (English)

    王忠; 季文; 张瑞琴

    2013-01-01

    Objective To investigate the Pseudomonas aeruginosa biofilm by using confocal laser scanning microscopy (CLSM), thus revealing the formation of biofilm. Methods The cover slide biofilm culture approach was employed for induction of Pseudomonas aeruginosa biofilm formation. Following the culture for 2, 4, 8, 12, 16, 24, 48 and 72 hours, the cover slide was removed for subsequent staining with the fluoreseein isothiocyanate-labeled con-eanavalin A (FTTC-ConA) and iodidepyrtdine (PI)- This was followed by determination of the formation and characteristics of Pseudomonas aeruginosa biofilm by using CXSM. Results The CLSM images of biofilm formation at different time points were captured, suggesting that the biofilm formed at hour 24 and grew robustly at hour 72. Conclusion The double immunofluorescence staining and CLSM are effective means for assessment of Pseudomonas aeruginosa biofilm formation.%目的 采用激光共聚焦显微镜技术观察铜绿假单胞菌形成生物膜,进一步揭示了铜绿假单胞菌生物膜形成过程.方法 使用盖玻片生物膜培养法,培养铜绿假单胞菌的生物膜,在培养2、4、8、12、16、24、48和72 h后取出盖玻片,用异硫氰酸荧光素(FTTC)标记的刀豆蛋白A(FTTC-ConA)和碘化吡啶(PI)双重免疫荧光技术染色,用激光共聚焦显微镜(CLSM)观察铜绿假单胞菌生物膜形成过程与特点.结果 获得生物膜形成过程不同时间点的CLSM图像,观察到铜绿假单胞菌一般在24h后开始逐渐形成生物膜,在72 h形成稳定的生物膜.结论 双重免疫荧光染色技术和CLSM是观察细菌生物膜形成过程的有效手段.

  11. Mechanistic insights into c-di-GMP–dependent control of the biofilm regulator FleQ from Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Matsuyama, Bruno Y.; Krasteva, Petya V.; Baraquet, Claudine; Harwood, Caroline S.; Sondermann, Holger; Navarro, Marcos V.A. S. (UWASH); (U. Sao Paulo); (Cornell); (CNRS-UMR)

    2016-07-05

    Pseudomonas aeruginosa, an opportunistic pathogen that can cause fatal chronic infections, relies on the intracellular second-messenger c-di-GMP to form robust multicellular biofilms during host tissue colonization. c-di-GMP is sensed directly by the transcription regulator FleQ, which inversely regulates flagellar motility and exopolysaccharide secretion to secure a planktonic to sessile life-form transition. FleQ belongs to the diverse family of AAA+ ATPase enhancer-binding proteins, but how its noncanonical function on transcriptional regulation is controlled by c-di-GMP remains enigmatic. Here, we report structural and functional data that identify an unusual mode of c-di-GMP recognition accompanied by a major quaternary structure reorganization. Our analyses offer a consensus to previous studies and unique insights into the mechanism of action of FleQ and FleQ-like proteins.

  12. Unsaturated fatty acid, cis-2-decenoic acid, in combination with disinfectants or antibiotics removes pre-established biofilms formed by food-related bacteria.

    Science.gov (United States)

    Sepehr, Shayesteh; Rahmani-Badi, Azadeh; Babaie-Naiej, Hamta; Soudi, Mohammad Reza

    2014-01-01

    Biofilm formation by food-related bacteria and food-related pathogenesis are significant problems in the food industry. Even though much disinfection and mechanical procedure exist for removal of biofilms, they may fail to eliminate pre-established biofilms. cis-2 decenoic acid (CDA), an unsaturated fatty acid messenger produced by Pseudomonas aeruginosa, is reportedly capable of inducing the dispersion of established biofilms by multiple types of microorganisms. However, whether CDA has potential to boost the actions of certain antimicrobials is unknown. Here, the activity of CDA as an inducer of pre-established biofilms dispersal, formed by four main food pathogens; Staphylococcus aureus, Bacillus cereus, Salmonella enterica and E. coli, was measured using both semi-batch and continuous cultures bioassays. To assess the ability of CDA combined biocides treatments to remove pre-established biofilms formed on stainless steel discs, CFU counts were performed for both treated and untreated cultures. Eradication of the biofilms by CDA combined antibiotics was evaluated using crystal violet staining. The effect of CDA combined treatments (antibiotics and disinfectants) on biofilm surface area and bacteria viability was evaluated using fluorescence microscopy, digital image analysis and LIVE/DEAD staining. MICs were also determined to assess the probable inhibitory effects of CDA combined treatments on the growth of tested microorganisms' planktonic cells. Treatment of pre-established biofilms with only 310 nM CDA resulted in at least two-fold increase in the number of planktonic cells in all cultures. While antibiotics or disinfectants alone exerted a trivial effect on CFU counts and percentage of surface area covered by the biofilms, combinational treatments with both 310 nM CDA and antibiotics or disinfectants led to approximate 80% reduction in biofilm biomass. These data suggests that combined treatments with CDA would pave the way toward developing new strategies

  13. Unsaturated fatty acid, cis-2-decenoic acid, in combination with disinfectants or antibiotics removes pre-established biofilms formed by food-related bacteria.

    Directory of Open Access Journals (Sweden)

    Shayesteh Sepehr

    Full Text Available Biofilm formation by food-related bacteria and food-related pathogenesis are significant problems in the food industry. Even though much disinfection and mechanical procedure exist for removal of biofilms, they may fail to eliminate pre-established biofilms. cis-2 decenoic acid (CDA, an unsaturated fatty acid messenger produced by Pseudomonas aeruginosa, is reportedly capable of inducing the dispersion of established biofilms by multiple types of microorganisms. However, whether CDA has potential to boost the actions of certain antimicrobials is unknown. Here, the activity of CDA as an inducer of pre-established biofilms dispersal, formed by four main food pathogens; Staphylococcus aureus, Bacillus cereus, Salmonella enterica and E. coli, was measured using both semi-batch and continuous cultures bioassays. To assess the ability of CDA combined biocides treatments to remove pre-established biofilms formed on stainless steel discs, CFU counts were performed for both treated and untreated cultures. Eradication of the biofilms by CDA combined antibiotics was evaluated using crystal violet staining. The effect of CDA combined treatments (antibiotics and disinfectants on biofilm surface area and bacteria viability was evaluated using fluorescence microscopy, digital image analysis and LIVE/DEAD staining. MICs were also determined to assess the probable inhibitory effects of CDA combined treatments on the growth of tested microorganisms' planktonic cells. Treatment of pre-established biofilms with only 310 nM CDA resulted in at least two-fold increase in the number of planktonic cells in all cultures. While antibiotics or disinfectants alone exerted a trivial effect on CFU counts and percentage of surface area covered by the biofilms, combinational treatments with both 310 nM CDA and antibiotics or disinfectants led to approximate 80% reduction in biofilm biomass. These data suggests that combined treatments with CDA would pave the way toward

  14. Investigation of natural biofilms formed during the production of drinking water from surface water embankment filtration.

    Science.gov (United States)

    Emtiazi, Farahnaz; Schwartz, Thomas; Marten, Silke Mareike; Krolla-Sidenstein, Peter; Obst, Ursula

    2004-03-01

    Populations of bacteria in biofilms from different sites of a drinking water production system were analysed. Polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) analyses revealed changing DNA band patterns, suggesting a population shift during bank filtration and processing at the waterworks. In addition, common DNA bands that were attributed to ubiquitous bacteria were found. Biofilms even developed directly after UV disinfection (1-2m distance). Their DNA band patterns only partly agreed with those of the biofilms from the downstream distribution system. Opportunistic pathogenic bacteria in biofilms were analysed using PCR and Southern blot hybridisation (SBH). Surface water appeared to have a direct influence on the composition of biofilms in the drinking water distribution system. In spite of preceding filtration and UV disinfection, opportunistic pathogens such as atypical mycobacteria and Legionella spp. were found in biofilms of drinking water, and Pseudomonas aeruginosa was detected sporadically. Enterococci were not found in any biofilm. Bacterial cell counts in the biofilms from surface water to drinking water dropped significantly, and esterase and alanine-aminopeptidase activity decreased. beta-glucosidase activity was not found in the biofilms. Contrary to the results for planktonic bacteria, inhibitory effects were not observed in biofilms. This suggested an increased tolerance of biofilm bacteria against toxic compounds.

  15. Roles of type IV pili, flagellum-mediated motility and extracellular DNA in the formation of mature multicellular structures in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Barken, Kim B; Pamp, Sünje J; Yang, Liang;

    2008-01-01

    When grown as a biofilm in laboratory flow chambers Pseudomonas aeruginosa can develop mushroom-shaped multicellular structures consisting of distinct subpopulations in the cap and stalk portions. We have previously presented evidence that formation of the cap portion of the mushroom......-shaped structures in P. aeruginosa biofilms occurs via bacterial migration and depends on type IV pili (Mol Microbiol 50: 61-68). In the present study we examine additional factors involved in the formation of this multicellular substructure. While pilA mutants, lacking type IV pili, are deficient in mushroom cap...

  16. Validation of PqsD as an anti-biofilm target in Pseudomonas aeruginosa by development of small-molecule inhibitors.

    Science.gov (United States)

    Storz, Michael P; Maurer, Christine K; Zimmer, Christina; Wagner, Nathalie; Brengel, Christian; de Jong, Johannes C; Lucas, Simon; Müsken, Mathias; Häussler, Susanne; Steinbach, Anke; Hartmann, Rolf W

    2012-10-01

    2-Heptyl-4-hydroxyquinoline (HHQ) and Pseudomonas quinolone signal (PQS) are involved in the regulation of virulence factor production and biofilm formation in Pseudomonas aeruginosa. PqsD is a key enzyme in the biosynthesis of these signal molecules. Using a ligand-based approach, we have identified the first class of PqsD inhibitors. Simplification and rigidization led to fragments with high ligand efficiencies. These small molecules repress HHQ and PQS production and biofilm formation in P. aeruginosa. This validates PqsD as a target for the development of anti-infectives. PMID:22992202

  17. Sequential Treatment of Biofilms with Aztreonam and Tobramycin Is a Novel Strategy for Combating Pseudomonas aeruginosa Chronic Respiratory Infections.

    Science.gov (United States)

    Rojo-Molinero, Estrella; Macià, María D; Rubio, Rosa; Moyà, Bartolomé; Cabot, Gabriel; López-Causapé, Carla; Pérez, José L; Cantón, Rafael; Oliver, Antonio

    2016-05-01

    Traditional therapeutic strategies to control chronic colonization in cystic fibrosis (CF) patients are based on the use of a single nebulized antibiotic. In this study, we evaluated the therapeutic efficacy and dynamics of antibiotic resistance in Pseudomonas aeruginosa biofilms under sequential therapy with inhaled aztreonam (ATM) and tobramycin (TOB). Laboratory strains PAO1, PAOMS (hypermutable), PAOMA (mucoid), and PAOMSA (mucoid and hypermutable) and two hypermutable CF strains, 146-HSE (Liverpool epidemic strain [LES-1]) and 1089-HSE (ST1089), were used. Biofilms were developed using the flow cell system. Mature biofilms were challenged with peak and 1/10-peak concentrations of ATM (700 mg/liter and 70 mg/liter), TOB (1,000 mg/liter and 100 mg/liter), and their alternations (ATM/TOB/ATM and TOB/ATM/TOB) for 2 (t = 2), 4 (t = 4), and 6 days (t = 6). The numbers of viable cells (CFU) and resistant mutants were determined. Biofilm structural dynamics were monitored by confocal laser scanning microscopy and processed with COMSTAT and IMARIS software programs. TOB monotherapy produced an intense decrease in CFU that was not always correlated with a reduction in biomass and/or a bactericidal effect on biofilms, particularly for the CF strains. The ATM monotherapy bactericidal effect was lower, but effects on biofilm biomass and/or structure, including intense filamentation, were documented. The alternation of TOB and ATM led to an enhancement of the antibiofilm activity against laboratory and CF strains compared to that with the individual regimens, potentiating the bactericidal effect and/or the reduction in biomass, particularly at peak concentrations. Resistant mutants were not documented in any of the regimens at the peak concentrations and only anecdotally at the 1/10-peak concentrations. These results support the clinical evaluation of sequential regimens with inhaled antibiotics in CF, as opposed to the current maintenance treatments with just one

  18. Serratia Secondary Metabolite Prodigiosin Inhibits Pseudomonas aeruginosa Biofilm Development by Producing Reactive Oxygen Species that Damage Biological Molecules

    Science.gov (United States)

    Kimyon, Önder; Das, Theerthankar; Ibugo, Amaye I.; Kutty, Samuel K.; Ho, Kitty K.; Tebben, Jan; Kumar, Naresh; Manefield, Mike

    2016-01-01

    Prodigiosin is a heterocyclic bacterial secondary metabolite belonging to the class of tripyrrole compounds, synthesized by various types of bacteria including Serratia species. Prodigiosin has been the subject of intense research over the last decade for its ability to induce apoptosis in several cancer cell lines. Reports suggest that prodigiosin promotes oxidative damage to double-stranded DNA (dsDNA) in the presence of copper ions and consequently leads to inhibition of cell-cycle progression and cell death. However, prodigiosin has not been previously implicated in biofilm inhibition. In this study, the link between prodigiosin and biofilm inhibition through the production of redox active metabolites is presented. Our study showed that prodigiosin (500 μM) (extracted from Serratia marcescens culture) and a prodigiosin/copper(II) (100 μM each) complex have strong RNA and dsDNA cleaving properties while they have no pronounced effect on protein. Results support a role for oxidative damage to biomolecules by H2O2 and hydroxyl radical generation. Further, it was demonstrated that reactive oxygen species scavengers significantly reduced the DNA and RNA cleaving property of prodigiosin. P. aeruginosa cell surface hydrophobicity and biofilm integrity were significantly altered due to the cleavage of nucleic acids by prodigiosin or the prodigiosin/copper(II) complex. In addition, prodigiosin also facilitated the bactericidal activity. The ability of prodigiosinto cause nucleic acid degradation offers novel opportunities to interfere with extracellular DNA dependent bacterial biofilms. PMID:27446013

  19. Serratia secondary metabolite prodigiosin inhibit Pseudomonas aeruginosa biofilm development by producing reactive oxygen species that damage biological molecules.

    Directory of Open Access Journals (Sweden)

    Onder eKimyon

    2016-06-01

    Full Text Available Prodigiosin is a heterocyclic bacterial secondary metabolite belonging to the class of tripyrrole compounds, synthesized by various types of bacteria including Serratia species. Prodigiosin has been the subject of intense research over the last decade for its ability to induce apoptosis in several cancer cell lines. Reports suggest that prodigiosin promotes oxidative damage to double-stranded DNA (dsDNA in the presence of copper ions and consequently leads to inhibition of cell-cycle progression and cell death. However, prodigiosin has not been previously implicated in biofilm inhibition. In this study, the link between prodigiosin and biofilm inhibition through the production of redox active metabolites is presented. Our study showed that prodigiosin (500 µM (extracted from Serratia marcescens culture and a prodigiosin/copper(II (100 µM each complex have strong RNA and dsDNA cleaving properties while they have no pronounced effect on protein. Results support a role for oxidative damage to biomolecules by H2O2 and hydroxyl radical generation. Further, it was demonstrated that reactive oxygen species scavengers significantly reduced the DNA and RNA cleaving property of prodigiosin. P. aeruginosa cell surface hydrophobicity and biofilm integrity were significantly altered due to the cleavage of nucleic acids by prodigiosin or the prodigiosin/copper(II complex. In addition, prodigiosin also facilitated the bactericidal activity. The ability of prodigiosin to cause nucleic acid degradation offers novel opportunities to interfere with extracellular DNA dependent bacterial biofilms.

  20. Pharmacokinetics and pharmacodynamics of antibiotics in biofilm infections of Pseudomonas aeruginosa in vitro and in vivo

    DEFF Research Database (Denmark)

    Hengzhuang, Wang; Høiby, Niels; Ciofu, Oana

    2014-01-01

    Although progress on biofilm research has been obtained during the past decades, the treatment of biofilm infections with antibiotics remains a riddle. The pharmacokinetic (PK) and pharmacodynamic (PD) profiles of an antimicrobial agent provide important information helping to establish an effici......Although progress on biofilm research has been obtained during the past decades, the treatment of biofilm infections with antibiotics remains a riddle. The pharmacokinetic (PK) and pharmacodynamic (PD) profiles of an antimicrobial agent provide important information helping to establish...

  1. Bioguided Fractionation Shows Cassia alata Extract to Inhibit Staphylococcus epidermidis and Pseudomonas aeruginosa Growth and Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Samuel Takashi Saito

    2012-01-01

    Full Text Available Plant extracts have a long history to be used in folk medicine. Cassia alata extracts are known to exert antibacterial activity but details on compounds and mechanism of action remain poorly explored. We purified and concentrated the aqueous leaf extract of C. alata by reverse phase-solid phase extraction and screened the resulting CaRP extract for antimicrobial activity. CaRP extract exhibited antimicrobial activity for Pseudomonas aeruginosa, Staphylococcus epidermidis, S. aureus, and Bacillus subtilis. CaRP also inhibited biofilm formation of S. epidermidis and P. aeruginosa. Several bacterial growth-inhibiting compounds were detected when CaRP extract was fractionated by TLC chromatography coupled to bioautography agar overlay technique. HPLC chromatography of CaRP extract yielded 20 subfractions that were tested by bioautography for antimicrobial activity against S. aureus and S. epidermidis. Five bioactive fractions were detected and chemically characterized, using high-resolution mass spectrometry (qTOF-MS/MS. Six compounds from four fractions could be characterized as kaempferol, kaempferol-O-diglucoside, kaempferol-O-glucoside, quercetin-O-glucoside, rhein, and danthron. In the Salmonella/microsome assay CaRP showed weak mutagenicity (MI<3 only in strain TA98, pointing to a frameshift mutation activity. These results indicate that C. alata leaf extract contains a minimum of 7 compounds with antimicrobial activity and that these together or as single substance are active in preventing formation of bacterial biofilm, indicating potential for therapeutic applications.

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

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, Peter Østrup; Fiandaca, Mark J;

    2009-01-01

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

  3. 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

    be used for biofilm control in vivo. We constructed a Pseudomonas aeruginosa strain in which a reduction in the c-di-GMP level can be achieved via induction of the Escherichia coli YhjH c-di-GMP phosphodiesterase. Initial experiments showed that induction of yhjH expression led to dispersal...

  4. Backbone and sidechain 1H, 15N and 13C assignments of Tyrosine Phosphatase related to Biofilm formation A (TpbA) of Pseudomonas aeruginosa

    OpenAIRE

    Koveal, Dorothy; Jayasundera, Thusitha B.; Wood, Thomas K.; Peti, Wolfgang; Page, Rebecca

    2012-01-01

    The backbone and side chain resonance assignments of the Tyrosine Phosphatase related to Biofilm formation A (TpbA) of Pseudomonas aeruginosa have been determined based on triple-resonance experiments using uniformly [13C,15N]-labeled protein. This assignment is the first step towards the determination of the 3-dimensional structure of TpbA.

  5. The effects of hyperosmosis or high pH on a dual-species biofilm of Enterococcus faecalis and Pseudomonas aeruginosa : an in vitro study

    NARCIS (Netherlands)

    van der Waal, S. V.; van der Sluis, L. W. M.; Ozok, A. R.; Exterkate, R. A. M.; van Marle, J.; Wesselink, P. R.; de Soet, J. J.

    2011-01-01

    van der Waal SV, van der Sluis LWM, Ozok AR, Exterkate RAM, van Marle J, Wesselink PR, de Soet JJ. The effects of hyperosmosis or high pH on a dual-species biofilm of Enterococcus faecalis and Pseudomonas aeruginosa: an in vitro study. International Endodontic Journal, 44, 11101117, 2011. Aim To inv

  6. [The biological kinetics of biofilms of clinical strains of Staphylococcus aureus and Pseudomonas aeruginosa separated from patients with bronchopulmonary complications under traumatic disease of spinal cord].

    Science.gov (United States)

    Ul'ianov, V Iu; Opredelentseva, S V; Shvidenko, I G; Norkin, I A; Korshunov, G V; Gladkova, E V

    2014-08-01

    The capacity and intensity of formation of microbial biofilms was analyzed in 24 strains of Staphylococcus aureus and Pseudomonas aeruginosa in static conditions of cultivation during 24, 48, 72 and 96 yours. The microorganisms were separated from patients with bronchopulmonary infectious complications in acute and early periods of traumatic disease of spinal cord.

  7. Statistical Analysis of Pseudomonas aeruginosa Biofilm Development: Impact of Mutations in Genes Involved in Twitching Motility, Cell-to-Cell Signaling, and Stationary-Phase Sigma Factor Expression

    DEFF Research Database (Denmark)

    Heydorn, Arne; Ersbøll, Bjarne Kjær; Kato, Junichi;

    2002-01-01

    Four strains of Pseudomonas aeruginosa (wild type, DeltapilHIJK mutant, lasI mutant, and rpoS mutant) were genetically tagged with the green fluorescent protein, and the development of flow chamber-grown biofilms by each of them was investigated by confocal laser scanning microscopy. The structural...

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

    OpenAIRE

    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 bacte...

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

    OpenAIRE

    Rosanna ePapa; Laura eSelan; Ermenegilda eParrilli; Marco eTilotta; Filomena eSannino; Georges eFeller; Maria Luisa eTutino; Marco eArtini

    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 bacte...

  10. Trigonella foenum-graceum (Seed) Extract Interferes with Quorum Sensing Regulated Traits and Biofilm Formation in the Strains of Pseudomonas aeruginosa and Aeromonas hydrophila.

    Science.gov (United States)

    Husain, Fohad Mabood; Ahmad, Iqbal; Khan, Mohd Shahnawaz; Al-Shabib, Nasser Abdulatif

    2015-01-01

    Trigonella foenum-graecum L. (Fenugreek) is an important plant of the Leguminosae family known to have medicinal properties. However, fraction based antiquorum sensing and antibiofilm activities have not been reported from this plant. In the present study T. foenum-graecum seed extract was sequentially fractionated and sub-MICs were tested for above activities. The methanol fraction of the extract demonstrated significant inhibition of AHL regulated virulence factors: protease, LasB elastase, pyocyanin production, chitinase, EPS, and swarming motility in Pseudomonas aeruginosa PAO1 and PAF79. Further, QS dependent virulence factor in the aquatic pathogen Aeromonas hydrophila WAF38 was also reduced. Application of T. foenum-graecum seed extract to PAO1, PAF79, and WAF38 decreased the biofilm forming abilities of the pathogens by significant levels. The extract also exhibited reduced AHL levels and subsequent downregulation of lasB gene. In vivo study showed an enhanced survival of PAO1-preinfected C. elegans after treatment with extract at 1 mg/mL. Further, the major compound detected by GC-MS, caffeine, reduced the production of QS regulated virulence factors and biofilm at 200 µg/mL concentration indicating its role in the activity of the methanol extract. The results of the present study reveal the potential anti-QS and antibiofilm property of T. foenum-graceum extract and caffeine. PMID:26000026

  11. Trigonella foenum-graceum (Seed Extract Interferes with Quorum Sensing Regulated Traits and Biofilm Formation in the Strains of Pseudomonas aeruginosa and Aeromonas hydrophila

    Directory of Open Access Journals (Sweden)

    Fohad Mabood Husain

    2015-01-01

    Full Text Available Trigonella foenum-graecum L. (Fenugreek is an important plant of the Leguminosae family known to have medicinal properties. However, fraction based antiquorum sensing and antibiofilm activities have not been reported from this plant. In the present study T. foenum-graecum seed extract was sequentially fractionated and sub-MICs were tested for above activities. The methanol fraction of the extract demonstrated significant inhibition of AHL regulated virulence factors: protease, LasB elastase, pyocyanin production, chitinase, EPS, and swarming motility in Pseudomonas aeruginosa PAO1 and PAF79. Further, QS dependent virulence factor in the aquatic pathogen Aeromonas hydrophila WAF38 was also reduced. Application of T. foenum-graecum seed extract to PAO1, PAF79, and WAF38 decreased the biofilm forming abilities of the pathogens by significant levels. The extract also exhibited reduced AHL levels and subsequent downregulation of lasB gene. In vivo study showed an enhanced survival of PAO1-preinfected C. elegans after treatment with extract at 1 mg/mL. Further, the major compound detected by GC-MS, caffeine, reduced the production of QS regulated virulence factors and biofilm at 200 µg/mL concentration indicating its role in the activity of the methanol extract. The results of the present study reveal the potential anti-QS and antibiofilm property of T. foenum-graceum extract and caffeine.

  12. Pseudomonas aeruginosa Exhibits Deficient Biofilm Formation in the Absence of Class II and III Ribonucleotide Reductases Due to Hindered Anaerobic Growth.

    Science.gov (United States)

    Crespo, Anna; Pedraz, Lucas; Astola, Josep; Torrents, Eduard

    2016-01-01

    Chronic lung infections by the ubiquitous and extremely adaptable opportunistic pathogen Pseudomonas aeruginosa correlate with the formation of a biofilm, where bacteria grow in association with an extracellular matrix and display a wide range of changes in gene expression and metabolism. This leads to increased resistance to physical stress and antibiotic therapies, while enhancing cell-to-cell communication. Oxygen diffusion through the complex biofilm structure generates an oxygen concentration gradient, leading to the appearance of anaerobic microenvironments. Ribonucleotide reductases (RNRs) are a family of highly sophisticated enzymes responsible for the synthesis of the deoxyribonucleotides, and they constitute the only de novo pathway for the formation of the building blocks needed for DNA synthesis and repair. P. aeruginosa is one of the few bacteria encoding all three known RNR classes (Ia, II, and III). Class Ia RNRs are oxygen dependent, class II are oxygen independent, and class III are oxygen sensitive. A tight control of RNR activity is essential for anaerobic growth and therefore for biofilm development. In this work we explored the role of the different RNR classes in biofilm formation under aerobic and anaerobic initial conditions and using static and continuous-flow biofilm models. We demonstrated the importance of class II and III RNR for proper cell division in biofilm development and maturation. We also determined that these classes are transcriptionally induced during biofilm formation and under anaerobic conditions. The molecular mechanism of their anaerobic regulation was also studied, finding that the Anr/Dnr system is responsible for class II RNR induction. These data can be integrated with previous knowledge about biofilms in a model where these structures are understood as a set of layers determined by oxygen concentration and contain cells with different RNR expression profiles, bringing us a step closer to the understanding of this

  13. Pseudomonas aeruginosa exhibits deficient biofilm formation in the absence of class II and III ribonucleotide reductases due to hindered anaerobic growth.

    Directory of Open Access Journals (Sweden)

    Anna eCrespo

    2016-05-01

    Full Text Available Chronic lung infections by the ubiquitous and extremely adaptable opportunistic pathogen Pseudomonas aeruginosa correlate with the formation of a biofilm, where bacteria grow in association with an extracellular matrix and display a wide range of changes in gene expression and metabolism. This leads to increased resistance to physical stress and antibiotic therapies, while enhancing cell-to-cell communication. Oxygen diffusion through the complex biofilm structure generates an oxygen concentration gradient, leading to the appearance of anaerobic microenvironments.Ribonucleotide reductases (RNRs are a family of highly sophisticated enzymes responsible for the synthesis of the deoxyribonucleotides, and they constitute the only de novo pathway for the formation of the building blocks needed for DNA synthesis and repair. P. aeruginosa is one of the few bacteria encoding all three known RNR classes (Ia, II and III. Class Ia RNRs are oxygen dependent, class II are oxygen independent, and class III are oxygen sensitive. A tight control of RNR activity is essential for anaerobic growth and therefore for biofilm development.In this work we explored the role of the different RNR classes in biofilm formation under aerobic and anaerobic initial conditions and using static and continuous-flow biofilm models. We demonstrated the importance of class II and III RNR for proper cell division in biofilm development and maturation. We also determined that these classes are transcriptionally induced during biofilm formation and under anaerobic conditions. The molecular mechanism of their anaerobic regulation was also studied, finding that the Anr/Dnr system is responsible for class II RNR induction. These data can be integrated with previous knowledge about biofilms in a model where these structures are understood as a set of layers determined by oxygen concentration and contain cells with different RNR expression profiles, bringing us a step closer to the

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    and fast growth. Conversely, chronic infections are often associated with the biofilm mode of growth, low virulence and slow growth that resembles that of planktonic cells in stationary phase. Biofilm formation and type III secretion have been shown to be reciprocally regulated, and it has been suggested...

  15. HD-GYP domain proteins regulate biofilm formation and virulence in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Ryan, Robert P.; Lucey, Jean; O'Donovan, Karen;

    2009-01-01

    HD-GYP is a protein domain involved in the hydrolysis of the bacterial second messenger cyclic-di-GMP. The genome of the human pathogen Pseudomonas aeruginosa PAO1 encodes two proteins (PA4108, PA4781) with an HD-GYP domain and a third protein, PA2572, which contains a domain with variant key res....... aeruginosa to larvae of the Greater Wax moth Galleria mellonella....

  16. Characterisation of biofilms formed by Lactobacillus plantarum WCFS1 and food spoilage isolates

    NARCIS (Netherlands)

    Fernández Ramírez, M.D.; Smid, E.J.; Abee, T.; Nierop Groot, M.N.

    2015-01-01

    Lactobacillus plantarum has been associated with food spoilage in a wide range of products and the biofilm growth mode has been implicated as a possible source of contamination. In this study we analysed the biofilm forming capacity of L. plantarum WCFS1 and six food spoilage isolates. Biofilm forma

  17. Biofilm-forming activity of bacteria isolated from toilet bowl biofilms and the bactericidal activity of disinfectants against the isolates.

    Science.gov (United States)

    Mori, Miho; Gomi, Mitsuhiro; Matsumune, Norihiko; Niizeki, Kazuma; Sakagami, Yoshikazu

    2013-01-01

    To evaluate the sanitary conditions of toilets, the bacterial counts of the toilet bowl biofilms in 5 Kansai area and 11 Kansai and Kanto area homes in Japan were measured in winter and summer seasons, respectively. Isolates (128 strains) were identified by analyzing 16S ribosomal RNA sequences. The number of colonies and bacterial species from biofilms sampled in winter tended to be higher and lower, respectively, than those in summer. Moreover, the composition of bacterial communities in summer and winter samples differed considerably. In summer samples, biofilms in Kansai and Kanto areas were dominated by Blastomonas sp. and Mycobacterium sp., respectively. Methylobacterium sp. was detected in all toilet bowl biofilms except for one sample. Methylobacterium sp. constituted the major presence in biofilms along with Brevundimonas sp., Sphingomonas sp., and/or Pseudomonas sp. The composition ratio of the sum of their genera was 88.0 from 42.9% of the total bacterial flora. The biofilm formation abilities of 128 isolates were investigated, and results suggested that Methylobacterium sp. and Sphingomonas sp. were involved in biofilm formation in toilet bowls. The biofilm formation of a mixed bacteria system that included bacteria with the highest biofilm-forming ability in a winter sample was greater than mixture without such bacteria. This result suggests that isolates possessing a high biofilm-forming activity are involved in the biofilm formation in the actual toilet bowl. A bactericidal test against 25 strains indicated that the bactericidal activities of didecyldimethylammonium chloride (DDAC) tended to be higher than those of polyhexamethylene biguanide (PHMB) and N-benzyl-N,N-dimethyldodecylammonium chloride (ADBAC). In particular, DDAC showed high bactericidal activity against approximately 90% of tested strains under the 5 h treatment.

  18. Next Generation Biofilm Inhibitors for Pseudomonas aeruginosa: Synthesis and Rational Design Approaches

    Digital Repository Service at National Institute of Oceanography (India)

    Majik, M.S.; Parvatkar, P.T.

    The bacterial biofilms and the emergence of multiple drug resistance have become a major threat for current medical treatment of nosocomial infections. It has been estimated that about 65-80% of microbial infections in the developed countries...

  19. Visualization of Microbiological Processes Underlying Stress Relaxation in Pseudomonas aeruginosa Biofilms

    NARCIS (Netherlands)

    Peterson, Brandon W.; Busscher, Henk J.; Sharma, Prashant K.; van der Mei, Henny C.

    2014-01-01

    Bacterial biofilms relieve themselves from external stresses through internal rearrangement, as mathematically modeled in many studies, but never microscopically visualized for their underlying microbiological processes. The aim of this study was to visualize rearrangement processes occurring in mec

  20. Efflux as a Glutaraldehyde Resistance Mechanism in Pseudomonas fluorescens and Pseudomonas aeruginosa Biofilms

    OpenAIRE

    Vikram, Amit; Jennifer M Bomberger; Kyle J Bibby

    2015-01-01

    A major challenge in microbial biofilm control is biocide resistance. Phenotypic adaptations and physical protective effects have been historically thought to be the primary mechanisms for glutaraldehyde resistance in bacterial biofilms. Recent studies indicate the presence of genetic mechanisms for glutaraldehyde resistance, but very little is known about the contributory genetic factors. Here, we demonstrate that efflux pumps contribute to glutaraldehyde resistance in Pseudomonas fluorescen...

  1. 铜绿假单胞菌细菌生物膜形成及耐药性分析%Formation of pseudomonas aeruginosa biofilm and antibiotic resistance

    Institute of Scientific and Technical Information of China (English)

    袁晨燕; 韩勍; 陈建明; 芦慧霞

    2011-01-01

    目的 建立铜绿假单胞菌细菌生物膜模型,比较浮游状态和生物膜中铜绿假单胞菌对临床常用抗菌药物的耐药性.方法 用临床分离的铜绿假单胞菌孵育医用硅胶材料(硅胶导尿管)建立细菌生物膜,经银染法和扫描电镜观察生物膜的形成情况,测定 6种抗菌药物对分离菌在浮游状态的最低抑菌浓度(MIC)、最小杀菌浓度(MBC)及生物膜形成以后最小生物膜清除浓度(MBEc).结果 经银染法和扫描电镜观察,导尿管表面形成了细菌生物膜;抗菌药物对生物膜的MBEC为浮游状态下MIC和MBC的100~1000倍.结论 体外建立细菌生物膜,并经银染法观察生物膜的形成是方便可行的;铜绿假单胞菌形成细菌生物膜以后对常用抗菌药物的耐药性远远高于浮游菌.%OBJECTIVE To establish the models of Pseudomonas aeruginosa, to compare the antibiotic susceptibility of P. aeruginosa in biofilms versus its counterparts in planctonic culture. METHODS Incubated isolates from clinic with the silicon catheters and observed the formation of biofilm on catheters by silver staining and scanning electron microscopy (SEM). Assay of determination the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the planctonic cells and the minimal biofilm eradication concentration (MBEC) of the cells in biofilm were undertaken. RESULTS P. aeruginosa biofilms were observed on the surface of catheters. The MBEC was 100 - 1000 times than MIC and MBC. CONCLUSION The assay of establishing P. aeruginosa biofilm and observed by silver staining is convenient and feasible. P. aeruginosa in biofilm exhibits far more resistance to antimicrobial than its planctonic counterparts does.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    The fap operon, encoding functional amyloids in Pseudomonas (Fap), is present in most pseudomonads, but so far the expression and importance for biofilm formation has only been investigated for P. fluorescens strain UK4. In this study, we demonstrate the capacity of P. aeruginosa PAO1, P. fluorescens...... Pf-5, and P. putida F1 to express Fap fibrils, and investigated the effect of Fap expression on aggregation and biofilm formation. The fap operon in all three Pseudomonas species conferred the ability to express Fap fibrils as shown using a recombinant approach. This Fap overexpression consistently...

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

    NARCIS (Netherlands)

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

    2005-01-01

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

  4. 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

    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...

  5. Cell surface physico chemistry alters biofilm development of Pseudomonas aeruginosa lipopolysaccharide mutants

    NARCIS (Netherlands)

    Flemming, CA; Palmer, RJ; Arrage, AA; Van der Mei, HC; White, DC

    1999-01-01

    The hydrophobic and electrostatic characteristics of bacterial cell surfaces were compared with attachment proclivity and biomass accumulation over time between wildtype Pseudomonas aeruginosa serotype O6 (possesses A and B band LPS), and three LPS-deficient mutants, vi;. A28 (A(+)B(-)), R5 (A(+)B(-

  6. Inhibition of Aspergillus fumigatus and Its Biofilm by Pseudomonas aeruginosa Is Dependent on the Source, Phenotype and Growth Conditions of the Bacterium.

    Science.gov (United States)

    Ferreira, Jose A G; Penner, John C; Moss, Richard B; Haagensen, Janus A J; Clemons, Karl V; Spormann, Alfred M; Nazik, Hasan; Cohen, Kevin; Banaei, Niaz; Carolino, Elisabete; Stevens, David A

    2015-01-01

    Aspergillus fumigatus (Af) and Pseudomonas aeruginosa (Pa) are leading fungal and bacterial pathogens, respectively, in many clinical situations. Relevant to this, their interface and co-existence has been studied. In some experiments in vitro, Pa products have been defined that are inhibitory to Af. In some clinical situations, both can be biofilm producers, and biofilm could alter their physiology and affect their interaction. That may be most relevant to airways in cystic fibrosis (CF), where both are often prominent residents. We have studied clinical Pa isolates from several sources for their effects on Af, including testing involving their biofilms. We show that the described inhibition of Af is related to the source and phenotype of the Pa isolate. Pa cells inhibited the growth and formation of Af biofilm from conidia, with CF isolates more inhibitory than non-CF isolates, and non-mucoid CF isolates most inhibitory. Inhibition did not require live Pa contact, as culture filtrates were also inhibitory, and again non-mucoid>mucoid CF>non-CF. Preformed Af biofilm was more resistant to Pa, and inhibition that occurred could be reproduced with filtrates. Inhibition of Af biofilm appears also dependent on bacterial growth conditions; filtrates from Pa grown as biofilm were more inhibitory than from Pa grown planktonically. The differences in Pa shown from these different sources are consistent with the extensive evolutionary Pa changes that have been described in association with chronic residence in CF airways, and may reflect adaptive changes to life in a polymicrobial environment.

  7. Biofilm-Forming Staphylococcus epidermidis Expressing Vancomycin Resistance Early after Adhesion to a Metal Surface

    Directory of Open Access Journals (Sweden)

    Toshiyuki Sakimura

    2015-01-01

    Full Text Available We investigated biofilm formation and time of vancomycin (VCM resistance expression after adhesion to a metal surface in Staphylococcus epidermidis. Biofilm-forming Staphylococcus epidermidis with a VCM MIC of 1 μg/mL was used. The bacteria were made to adhere to a stainless steel washer and treated with VCM at different times and concentrations. VCM was administered 0, 2, 4, and 8 hours after adhesion. The amount of biofilm formed was evaluated based on the biofilm coverage rates (BCRs before and after VCM administration, bacterial viability in biofilm was visually observed using the fluorescence staining method, and the viable bacterial count in biofilm was measured. The VCM concentration required to decrease BCR significantly compared with that of VCM-untreated bacteria was 4 μg/mL, even in the 0 hr group. In the 4 and 8 hr groups, VCM could not inhibit biofilm growth even at 1,024 μg/mL. In the 8 hr group, viable bacteria remained in biofilm at a count of 104 CFU even at a high VCM concentration (1,024 μg/mL. It was suggested that biofilm-forming Staphylococcus epidermidis expresses resistance to VCM early after adhesion to a metal surface. Resistance increased over time after adhesion as the biofilm formed, and strong resistance was expressed 4–8 hours after adhesion.

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

    DEFF Research Database (Denmark)

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

    2005-01-01

    The opportunistic human pathogen Pseudomonas aeruginosa is the predominant micro-organism of chronic lung infections in cystic fibrosis patients. P. aeruginosa colonizes the lungs by forming biofilm microcolonies throughout the lung. Quorum sensing (QS) renders the biofilm bacteria highly tolerant......-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....

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

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

  10. Ligand Binding Reduces Conformational Flexibility in the Active Site of Tyrosine Phosphatase Related to Biofilm Formation A (TpbA) from Pseudomonas aeruginosa

    OpenAIRE

    Koveal, Dorothy; Clarkson, Michael W.; Wood, Thomas K.; Page, Rebecca; Peti, Wolfgang

    2013-01-01

    TpbA is a periplasmic dual specificity phosphatase (DUSP) that controls biofilm formation in the pathogenic bacterium, Pseudomonas aeruginosa. While DUSPs are known to regulate important cellular functions in both prokaryotes and eukaryotes, very few structures of bacterial DUSPs are available. Here, we present the solution structure of TpbA in the ligand-free open conformation, along with an analysis of the structural and dynamic changes that accompany ligand/phosphate binding. While TpbA ad...

  11. D-amino acids trigger biofilm disassembly.

    Science.gov (United States)

    Kolodkin-Gal, Ilana; Romero, Diego; Cao, Shugeng; Clardy, Jon; Kolter, Roberto; Losick, Richard

    2010-04-30

    Bacteria form communities known as biofilms, which disassemble over time. In our studies outlined here, we found that, before biofilm disassembly, Bacillus subtilis produced a factor that prevented biofilm formation and could break down existing biofilms. The factor was shown to be a mixture of D-leucine, D-methionine, D-tyrosine, and D-tryptophan that could act at nanomolar concentrations. D-amino acid treatment caused the release of amyloid fibers that linked cells in the biofilm together. Mutants able to form biofilms in the presence of D-amino acids contained alterations in a protein (YqxM) required for the formation and anchoring of the fibers to the cell. D-amino acids also prevented biofilm formation by Staphylococcus aureus and Pseudomonas aeruginosa. D-amino acids are produced by many bacteria and, thus, may be a widespread signal for biofilm disassembly. PMID:20431016

  12. Effects of Photoactivated Titanium Dioxide Nanopowders and Coating on Planktonic and Biofilm Growth of Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Polo, Andrea; Diamanti, Maria Vittoria; Bjarnsholt, Thomas;

    2011-01-01

    We exploited the ability of photocatalytic titanium dioxide (TiO(2) ) as an agent for the biofilm control. Two photocatalytic systems were investigated: a 3g/l suspension of TiO(2) nanopowder in demineralised water and glass slides coated with a TiO(2) thin film, achieved by sol-gel deposition...

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

    Directory of Open Access Journals (Sweden)

    Aylin Ugurlu

    2016-08-01

    Conclusions: We may suggest that if swarming and consecutive biofilm formation could be inhibited by the natural products as shown in our study, the bacteria could not attach to the surfaces and produce chronic infections. Antimicrobials and natural products could be combined and the dosage of antimicrobials could be reduced to overcome antimicrobial resistance and drug side effects.

  14. 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

    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, howe...

  15. The antimicrobial action of Pseudomonas aeruginosa byproducts in the control of single and mixed biofilms

    OpenAIRE

    Lopes, Susana Patrícia; Machado, Idalina; Pereira, Maria Olívia

    2010-01-01

    Since bacteria are continuously acquiring resistance to conventional chemical agents, it is urgently needed the development of new strategies for biofilm control. It is well recognised that certain microorganisms represent an important source of novel biologically active compounds, with pronounced antibacterial activity, as secondary metabolites. Such substances are accepted to be essential for their producers, inhibiting other bacteria that compete for common resource...

  16. Microbiologically Influenced Corrosion of 2707 Hyper-Duplex Stainless Steel by Marine Pseudomonas aeruginosa Biofilm

    OpenAIRE

    Huabing Li; Enze Zhou; Dawei Zhang; Dake Xu; Jin Xia; Chunguang Yang; Hao Feng; Zhouhua Jiang; Xiaogang Li; Tingyue Gu; Ke Yang

    2016-01-01

    Microbiologically Influenced Corrosion (MIC) is a serious problem in many industries because it causes huge economic losses. Due to its excellent resistance to chemical corrosion, 2707 hyper duplex stainless steel (2707 HDSS) has been used in the marine environment. However, its resistance to MIC was not experimentally proven. In this study, the MIC behavior of 2707 HDSS caused by the marine aerobe Pseudomonas aeruginosa was investigated. Electrochemical analyses demonstrated a positive shift...

  17. Antimicrobial activities against biofilm formed by Proteus mirabilis isolates from wound and urinary tract infections

    Directory of Open Access Journals (Sweden)

    R Wasfi

    2012-01-01

    Full Text Available Background: Bacterial species are capable of living as biofilm and/or planktonic forms. There is increasing evidence for the role of bacterial biofilm in various wound and urinary tract infections (UTIs. The aim of the present study was to evaluate the ability of the bacteria, isolated from urinary tract infections (UTIs and wound infections, to form biofilm and correlate the role of biofilm with their antimicrobial resistance. Materials and Methods: All the isolated bacteria were screened for their ability to form biofilm using the microtitre plate method. Results: Wound isolates of Staphylococcus aureus and Enterobacter sp. had more biofilm forming capacity than the UTI isolates. Proteus mirabilis isolates were among the strongest biofilm forming bacteria and were chosen for antimicrobial study. In sub-MIC concentrations of antimicrobial agents used, ciprofloxacin was found to be the most effective in decreasing biofilm formation. On the other hand, ceftriaxone and ciprofloxacin were effective in partial removal of preformed biofilm biomass. Conclusion: Ciprofloxacin was more effective in killing bacterial cells especially at high antimicrobial concentrations that could be reached in urine levels and can be used in impregenating catheters.

  18. Manuka-type honeys can eradicate biofilms produced by Staphylococcus aureus strains with different biofilm-forming abilities

    Directory of Open Access Journals (Sweden)

    Jing Lu

    2014-03-01

    Full Text Available Chronic wounds are a major global health problem. Their management is difficult and costly, and the development of antibiotic resistance by both planktonic and biofilm-associated bacteria necessitates the use of alternative wound treatments. Honey is now being revisited as an alternative treatment due to its broad-spectrum antibacterial activity and the inability of bacteria to develop resistance to it. Many previous antibacterial studies have used honeys that are not well characterized, even in terms of quantifying the levels of the major antibacterial components present, making it difficult to build an evidence base for the efficacy of honey as an antibiofilm agent in chronic wound treatment. Here we show that a range of well-characterized New Zealand manuka-type honeys, in which two principle antibacterial components, methylglyoxal and hydrogen peroxide, were quantified, can eradicate biofilms of a range of Staphylococcus aureus strains that differ widely in their biofilm-forming abilities. Using crystal violet and viability assays, along with confocal laser scanning imaging, we demonstrate that in all S. aureus strains, including methicillin-resistant strains, the manuka-type honeys showed significantly higher anti-biofilm activity than clover honey and an isotonic sugar solution. We observed higher anti-biofilm activity as the proportion of manuka-derived honey, and thus methylglyoxal, in a honey blend increased. However, methylglyoxal on its own, or with sugar, was not able to effectively eradicate S. aureus biofilms. We also demonstrate that honey was able to penetrate through the biofilm matrix and kill the embedded cells in some cases. As has been reported for antibiotics, sub-inhibitory concentrations of honey improved biofilm formation by some S. aureus strains, however, biofilm cell suspensions recovered after honey treatment did not develop resistance towards manuka-type honeys. New Zealand manuka-type honeys, at the concentrations

  19. Manuka-type honeys can eradicate biofilms produced by Staphylococcus aureus strains with different biofilm-forming abilities.

    Science.gov (United States)

    Lu, Jing; Turnbull, Lynne; Burke, Catherine M; Liu, Michael; Carter, Dee A; Schlothauer, Ralf C; Whitchurch, Cynthia B; Harry, Elizabeth J

    2014-01-01

    Chronic wounds are a major global health problem. Their management is difficult and costly, and the development of antibiotic resistance by both planktonic and biofilm-associated bacteria necessitates the use of alternative wound treatments. Honey is now being revisited as an alternative treatment due to its broad-spectrum antibacterial activity and the inability of bacteria to develop resistance to it. Many previous antibacterial studies have used honeys that are not well characterized, even in terms of quantifying the levels of the major antibacterial components present, making it difficult to build an evidence base for the efficacy of honey as an antibiofilm agent in chronic wound treatment. Here we show that a range of well-characterized New Zealand manuka-type honeys, in which two principle antibacterial components, methylglyoxal and hydrogen peroxide, were quantified, can eradicate biofilms of a range of Staphylococcus aureus strains that differ widely in their biofilm-forming abilities. Using crystal violet and viability assays, along with confocal laser scanning imaging, we demonstrate that in all S. aureus strains, including methicillin-resistant strains, the manuka-type honeys showed significantly higher anti-biofilm activity than clover honey and an isotonic sugar solution. We observed higher anti-biofilm activity as the proportion of manuka-derived honey, and thus methylglyoxal, in a honey blend increased. However, methylglyoxal on its own, or with sugar, was not able to effectively eradicate S. aureus biofilms. We also demonstrate that honey was able to penetrate through the biofilm matrix and kill the embedded cells in some cases. As has been reported for antibiotics, sub-inhibitory concentrations of honey improved biofilm formation by some S. aureus strains, however, biofilm cell suspensions recovered after honey treatment did not develop resistance towards manuka-type honeys. New Zealand manuka-type honeys, at the concentrations they can be applied

  20. Biofilm initiation and growth of Pseudomonas aeruginosa on 316L stainless steel in low gravity in orbital space flight

    Science.gov (United States)

    Todd, Paul; Pierson, Duane L.; Allen, Britt; Silverstein, JoAnn

    The formation of biofilms by water microorganisms such as Pseudomonas aeruginosa in spacecraft water systems has been a matter of concern for long-duration space flight. Crewed spacecraft plumbing includes internal surfaces made of 316L stainless steel. Experiments were therefore undertaken to compare the ability of P. aeruginosa to grow in suspension, attach to stainless steel and to grow on stainless steel in low gravity on the space shuttle. Four categories of cultures were studied during two space shuttle flights (STS-69 and STS-77). Cultures on the ground were held in static horizontal or vertical cylindrical containers or were tumbled on a clinostat and activated under conditions identical to those for the flown cultures. The containers used on the ground and in flight were BioServe Space Technologies’ Fluid Processing Apparatus (FPA), an open-ended test tube with rubber septa that allows robotic addition of bacteria to culture media to initiate experiments and the addition of fixative to conclude experiments. Planktonic growth was monitored by spectrophotometry, and biofilms were characterized quantitatively by epifluorescence and scanning electron microscopy. In these experiments it was found that: (1) Planktonic growth in flown cultures was more extensive than in static cultures, as seen repeatedly in the history of space microbiology, and closely resembled the growth of tumbled cultures. (2) Conversely, the attachment of cells in flown cultures was as much as 8 times that in tumbled cultures but not significantly different from that in static horizontal and vertical cultures, consistent with the notion that flowing fluid reduces microbial attachment. (3) The final surface coverage in 8 days was the same for flown and static cultures but less by a factor of 15 in tumbled cultures, where coverage declined during the preceding 4 days. It is concluded that cell attachment to 316L stainless steel in the low gravity of orbital space flight is similar to that

  1. Rifampicin fails to eradicate mature biofilm formed by methicillin-resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Keli Cristine Reiter

    2012-08-01

    Full Text Available INTRODUCTION: Antimicrobial activity on biofilms depends on their molecular size, positive charges, permeability coefficient, and bactericidal activity. Vancomycin is the primary choice for methicillin-resistant Staphylococcus aureus (MRSA infection treatment; rifampicin has interesting antibiofilm properties, but its effectivity remains poorly defined. METHODS: Rifampicin activity alone and in combination with vancomycin against biofilm-forming MRSA was investigated, using a twofold serial broth microtiter method, biofilm challenge, and bacterial count recovery. RESULTS: Minimal inhibitory concentration (MIC and minimal bactericidal concentration for vancomycin and rifampicin ranged from 0.5 to 1mg/l and 0.008 to 4mg/l, and from 1 to 4mg/l and 0.06 to 32mg/l, respectively. Mature biofilms were submitted to rifampicin and vancomycin exposure, and minimum biofilm eradication concentration ranged from 64 to 32,000 folds and from 32 to 512 folds higher than those for planktonic cells, respectively. Vancomycin (15mg/l in combination with rifampicin at 6 dilutions higher each isolate MIC did not reach in vitro biofilm eradication but showed biofilm inhibitory capacity (1.43 and 0.56log10 CFU/ml reduction for weak and strong biofilm producers, respectively; p<0.05. CONCLUSIONS: In our setting, rifampicin alone failed to effectively kill biofilm-forming MRSA, demonstrating stronger inability to eradicate mature biofilm compared with vancomycin.

  2. Characterisation of biofilms formed by Lactobacillus plantarum WCFS1 and food spoilage isolates.

    Science.gov (United States)

    Fernández Ramírez, Mónica D; Smid, Eddy J; Abee, Tjakko; Nierop Groot, Masja N

    2015-08-17

    Lactobacillus plantarum has been associated with food spoilage in a wide range of products and the biofilm growth mode has been implicated as a possible source of contamination. In this study we analysed the biofilm forming capacity of L. plantarum WCFS1 and six food spoilage isolates. Biofilm formation as quantified by crystal violet staining and colony forming units was largely affected by the medium composition, growth temperature and maturation time and by strain specific features. All strains showed highest biofilm formation in Brain Heart Infusion medium supplemented with manganese and glucose. For L. plantarum biofilms the crystal violet (CV) assay, that is routinely used to quantify total biofilm formation, correlates poorly with the number of culturable cells in the biofilm. This can in part be explained by cell death and lysis resulting in CV stainable material, conceivably extracellular DNA (eDNA), contributing to the extracellular matrix. The strain to strain variation may in part be explained by differences in levels of eDNA, likely as result of differences in lysis behaviour. In line with this, biofilms of all strains tested, except for one spoilage isolate, were sensitive to DNase treatment. In addition, biofilms were highly sensitive to treatment with Proteinase K suggesting a role for proteins and/or proteinaceous material in surface colonisation. This study shows the impact of a range of environmental factors and enzyme treatments on biofilm formation capacity for selected L. plantarum isolates associated with food spoilage, and may provide clues for disinfection strategies in food industry.

  3. Mechanistic insights into c-di-GMP-dependent control of the biofilm regulator FleQ from Pseudomonas aeruginosa.

    Science.gov (United States)

    Matsuyama, Bruno Y; Krasteva, Petya V; Baraquet, Claudine; Harwood, Caroline S; Sondermann, Holger; Navarro, Marcos V A S

    2016-01-12

    Bacterial biofilm formation during chronic infections confers increased fitness, antibiotic tolerance, and cytotoxicity. In many pathogens, the transition from a planktonic lifestyle to collaborative, sessile biofilms represents a regulated process orchestrated by the intracellular second-messenger c-di-GMP. A main effector for c-di-GMP signaling in the opportunistic pathogen Pseudomonas aeruginosa is the transcription regulator FleQ. FleQ is a bacterial enhancer-binding protein (bEBP) with a central AAA+ ATPase σ(54)-interaction domain, flanked by a C-terminal helix-turn-helix DNA-binding motif and a divergent N-terminal receiver domain. Together with a second ATPase, FleN, FleQ regulates the expression of flagellar and exopolysaccharide biosynthesis genes in response to cellular c-di-GMP. Here we report structural and functional data that reveal an unexpected mode of c-di-GMP recognition that is associated with major conformational rearrangements in FleQ. Crystal structures of FleQ's AAA+ ATPase domain in its apo-state or bound to ADP or ATP-γ-S show conformations reminiscent of the activated ring-shaped assemblies of other bEBPs. As revealed by the structure of c-di-GMP-complexed FleQ, the second messenger interacts with the AAA+ ATPase domain at a site distinct from the ATP binding pocket. c-di-GMP interaction leads to active site obstruction, hexameric ring destabilization, and discrete quaternary structure transitions. Solution and cell-based studies confirm coupling of the ATPase active site and c-di-GMP binding, as well as the functional significance of crystallographic interprotomer interfaces. Taken together, our data offer unprecedented insight into conserved regulatory mechanisms of gene expression under direct c-di-GMP control via FleQ and FleQ-like bEBPs.

  4. Regulation of biofilm formation in Pseudomonas aeruginosa by quorum sensing%群体感应对铜绿假单胞菌生物被膜形成的调控

    Institute of Scientific and Technical Information of China (English)

    黄媛媛; 宋水山

    2011-01-01

    生物被膜是一种与浮游细胞相对应的生长方式,由细菌和自身分泌的包外基质组成.铜绿假单胞菌是研究这一生长方式的模式生物.在过去十年,对铜绿假单胞菌生物被膜的研究已取得显著进展.群体感应(QS)的细胞沟通机制在铜绿假单胞菌生物被膜形成中发挥着重要作用.介绍生物被膜的特点,并重点讨论了QS和生物被膜之间的关系.%Compared with planktonic cells, bacterial biofilm is a kind of particular colonial life style which consists of bacteria and their extracellular matrix. Pseudomonas aeruginosa has become a model organism for studying biofilm formation. Over the past decade, significant strides have been made towards understanding biofilm development in Pseudomonas aeruginosa. Quorum sensing (QS)has been found to play a role in Pseudomonas aeruginosa biofilm formation. This paper introduced the biofilm characteristics,focusing on the relationship between QS and biofilm formation in Pseudomonas aeruginosa biofilm.

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

    OpenAIRE

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

    2013-01-01

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

  6. 铜绿假单胞菌群体感应lasI/rhlI基因对其生物被膜形成的影响%Effects of lasI/rhlI genes of Pseudomonas aeruginosa quorum-sensing system on biofilm formation

    Institute of Scientific and Technical Information of China (English)

    胡昌俊; 李德辉; 朱艮苗

    2013-01-01

    目的 分析铜绿假单胞菌群体感应系统lasI/rhlI基因对生物被膜形成的影响,探讨群体感应系统对生物被膜形成的调控机制.方法 采用结晶紫染色法分析铜绿假单胞菌标准株PAO1及其群体感应系统lasI/rhlI基因缺陷株PA210(△rhlI)、PA214(△lasI)及PA216(△lasI/rhlI)生物被膜的形成能力.结果 铜绿假单胞菌标准株PAO1能形成成熟的生物被膜,基因缺陷株PA214(△lasI)可形成较薄的生物被膜,而PA210(△rhlI)及PA216(△lasI/rhlI)则不能形成生物被膜.结论 lasI/rhlI基因缺陷可影响铜绿假单胞菌生物被膜形成,但rhlI基因对生物被膜形成的影响更为显著.%Objective To analyze the influence of Pseudomonas aeruginosa quorum-sensing system genes lasI/rhlI on bacterial biofilm formation,in order to explore the control mechanism of quorum-sensing system on the biofilm formation.Methods The formation ability of Pseudomonas aeruginosa standard strains PAO1 and quorum-sensing system lasI/rhlI genetic defect strains PA210(ΔrhlI),PA214(/lasI) and PA216(/lasI/rhlI) biofilm was analyzed by using crystal violet dyeing method.Results Pseudomonas aeruginosa standard strains PAO1 formed the mature biofilm,genetic defect strains PA214(/lasl) formed the thin biofilm,and PA210(/rhlI) and PA216(/lasI/rhlI) could not form biofilm.Conclusion lasI/rhlI genetic defects can affect the formation of Pseudomonas aeruginosa biofilm,but rhll gene influence more significant on the formation of biofilm.

  7. Behaviour of biofilms formed by Pseudomonas fluorescens under different flow regimes when exposed to surfactants : role of the biofilm mechanical stability

    OpenAIRE

    Simões, M; Pereira, M. O.; Vieira, M. J.

    2005-01-01

    The effectiveness of cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) to control biofilms formed by Pseudomonas fluorescens on stainless steel slides under laminar and turbulent conditions, using a flow cell reactor, is compared in this study. The antimicrobial action of the surfactants was evaluated in terms of the activity of the biofilm, the biofilm mass that remained on the surface after treatment and the biofilm morphological characteristics. The mec...

  8. Mixed biofilms formed by C. albicans and non-albicans species: a study of microbial interactions.

    Science.gov (United States)

    Santos, Jéssica Diane dos; Piva, Elisabete; Vilela, Simone Furgeri Godinho; Jorge, Antonio Olavo Cardoso; Junqueira, Juliana Campos

    2016-01-01

    Most Candida infections are related to microbial biofilms often formed by the association of different species. The objective of this study was to evaluate the interactions between Candida albicans and non-albicans species in biofilms formed in vitro. The non-albicans species studied were:Candida tropicalis, Candida glabrata and Candida krusei. Single and mixed biofilms (formed by clinical isolates of C. albicans and non-albicans species) were developed from standardized suspensions of each strain (10(7) cells/mL), on flat-bottom 96-well microtiter plates for 48 hour. These biofilms were analyzed by counting colony-forming units (CFU/mL) in Candida HiChrome agar and by determining cell viability, using the XTT 2,3-bis (2-methoxy-4-nitro-5-sulphophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide colorimetric assay. The results for both the CFU/mL count and the XTT colorimetric assay showed that all the species studied were capable of forming high levels of in vitro biofilm. The number of CFU/mL and the metabolic activity of C. albicans were reduced in mixed biofilms with non-albicans species, as compared with a single C. albicans biofilm. Among the species tested, C. krusei exerted the highest inhibitory action against C. albicans. In conclusion, C. albicans established antagonistic interactions with non-albicans Candida species in mixed biofilms.

  9. Antibiotic penetration and bacterial killing in a Pseudomonas aeruginosa biofilm model

    DEFF Research Database (Denmark)

    Cao, Bao; Christophersen, Lars; Thomsen, Kim;

    2015-01-01

    in the solution of homogenized beads was measured. Finally, beads were examined for live cells by Syto9 staining and for dead cells by propidium iodide staining using a confocal laser scanning microscope. RESULTS: The antibiotic level in each bead was relatively stable (range 30-42 mg/L; MIC = 1.5 mg...... by confocal laser scanning microscopy. More dead cells (measured by propidium iodide staining) were observed in the treated group of beads, which supports the results obtained by culture. CONCLUSIONS: The present study, simulating the clinical pharmacokinetics of tobramycin, demonstrates fast absorption...... model. METHODS: Seaweed alginate beads containing Pseudomonas aeruginosa were cultured in LB medium, sampled at day 1, 3, 5 or 7 and examined for the effect of treatment with tobramycin for 30 min. Treated beads were homogenized and the number of cfu was determined. The antibiotic concentration...

  10. The clinical impact of bacterial biofilms

    DEFF Research Database (Denmark)

    Høiby, Niels; Ciofu, Oana; Johansen, Helle Krogh;

    2011-01-01

    Bacteria survive in nature by forming biofilms on surfaces and probably most, if not all, bacteria (and fungi) are capable of forming biofilms. A biofilm is a structured consortium of bacteria embedded in a self-produced polymer matrix consisting of polysaccharide, protein and extracellular DNA....... Bacterial biofilms are resistant to antibiotics, disinfectant chemicals and to phagocytosis and other components of the innate and adaptive inflammatory defense system of the body. It is known, for example, that persistence of staphylococcal infections related to foreign bodies is due to biofilm formation....... Likewise, chronic Pseudomonas aeruginosa lung infections in cystic fibrosis patients are caused by biofilm growing mucoid strains. Gradients of nutrients and oxygen exist from the top to the bottom of biofilms and the bacterial cells located in nutrient poor areas have decreased metabolic activity...

  11. Helicobacter pylori-coccoid forms and biofilm formation

    DEFF Research Database (Denmark)

    Andersen, Leif Percival; Rasmussen, Lone

    2009-01-01

    be detected by PCR in water supplies. There is no substantial evidence for viable H. pylori persisting in water supplies. Epidemiological studies suggest that environmental water is a risk factor for H. pylori infection when compared with tap water, and formation of H. pylori biofilm cannot be excluded....... Helicobacter pylori does not seem to take part in biofilm formation in the oral cavity even though the bacterium may be detected....

  12. 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....... P. aeruginosa was grown in vitro in continuous-culture once-through flow chambers with and without garlic extract. The garlic-treated biofilms were susceptible to both tobramycin and PMN grazing. Furthermore, the PMNs showed an increase in respiratory burst activation, when incubated with the garlic...

  13. Inhibition of Aspergillus fumigatus and Its Biofilm by Pseudomonas aeruginosa Is Dependent on the Source, Phenotype and Growth Conditions of the Bacterium.

    Directory of Open Access Journals (Sweden)

    Jose A G Ferreira

    Full Text Available Aspergillus fumigatus (Af and Pseudomonas aeruginosa (Pa are leading fungal and bacterial pathogens, respectively, in many clinical situations. Relevant to this, their interface and co-existence has been studied. In some experiments in vitro, Pa products have been defined that are inhibitory to Af. In some clinical situations, both can be biofilm producers, and biofilm could alter their physiology and affect their interaction. That may be most relevant to airways in cystic fibrosis (CF, where both are often prominent residents. We have studied clinical Pa isolates from several sources for their effects on Af, including testing involving their biofilms. We show that the described inhibition of Af is related to the source and phenotype of the Pa isolate. Pa cells inhibited the growth and formation of Af biofilm from conidia, with CF isolates more inhibitory than non-CF isolates, and non-mucoid CF isolates most inhibitory. Inhibition did not require live Pa contact, as culture filtrates were also inhibitory, and again non-mucoid>mucoid CF>non-CF. Preformed Af biofilm was more resistant to Pa, and inhibition that occurred could be reproduced with filtrates. Inhibition of Af biofilm appears also dependent on bacterial growth conditions; filtrates from Pa grown as biofilm were more inhibitory than from Pa grown planktonically. The differences in Pa shown from these different sources are consistent with the extensive evolutionary Pa changes that have been described in association with chronic residence in CF airways, and may reflect adaptive changes to life in a polymicrobial environment.

  14. Biofilm-Forming Abilities of Listeria monocytogenes Serotypes Isolated from Different Sources.

    Directory of Open Access Journals (Sweden)

    Swapnil P Doijad

    Full Text Available A total of 98 previously characterized and serotyped L. monocytogenes strains, comprising 32 of 1/2a; 20 of 1/2b and 46 of 4b serotype, from clinical and food sources were studied for their capability to form a biofilm. The microtiter plate assay revealed 62 (63.26% strains as weak, 27 (27.55% strains as moderate, and 9 (9.18% strains as strong biofilm formers. Among the strong biofilm formers, 6 strains were of serotype 1/2a and 3 strains were of serotype 1/2b. None of the strain from 4b serotype exhibited strong biofilm formation. No firm correlation (p = 0.015 was noticed between any serotype and respective biofilm formation ability. Electron microscopic studies showed that strong biofilm forming isolates could synthesize a biofilm within 24 h on surfaces important in food industries such as stainless steel, ceramic tiles, high-density polyethylene plastics, polyvinyl chloride pipes, and glass. Cell enumeration of strong, moderate, and weak biofilm was performed to determine if the number of cells correlated with the biofilm-forming capabilities of the isolates. Strong, moderate, and weak biofilm showed 570±127× 103 cells/cm2, 33±26× 103 cells/cm2, 5±3× 103 cells/cm2, respectively, indicating that the number of cells was directly proportional to the strength of the biofilm. The hydrophobicity index (HI analysis revealed higher hydrophobicity with an increased biofilm formation. Fatty acid methyl esterase analysis revealed the amount of certain fatty acids such as iso-C15:0, anteiso-C15:0, and anteiso-C17:0 fatty acids correlated with the biofilm-forming capability of L. monocytogenes. This study showed that different strains of L. monocytogenes form biofilm of different intensities which did not completely correlate with their serotype; however, it correlated with the number of cells, hydrophobicity, and amount of certain fatty acids.

  15. Medicinal Plants Used by a Mbyá-Guarani Tribe Against Infections: Activity on KPC-Producing Isolates and Biofilm-Forming Bacteria.

    Science.gov (United States)

    Brandelli, Clara Lia Costa; Ribeiro, Vanessa Bley; Zimmer, Karine Rigon; Barth, Afonso Luís; Tasca, Tiana; Macedo, Alexandre José

    2015-11-01

    The traditional use of medicinal plants for treatment of infectious diseases by an indigenous Mbyá-Guarani tribe from South Brazil was assessed by evaluating the antibiotic and antibiofilm activities against relevant bacterial pathogens. Aqueous extracts from 10 medicinal plants were prepared according to indigenous Mbyá-Guarani traditional uses. To evaluate antibiotic (OD600) and antibiofilm (crystal violet method) activities, Pseudomonas aeruginosa ATCC 27853, Staphylococcus epidermidis ATCC 35984 and seven multi-drug resistant Klebsiella pneumoniae carbapenemase (KPC)-producing bacterial clinical isolates were challenged with the extracts. Furthermore, the susceptibility profile of KPC-producing bacteria and the ability of these isolates to form biofilm were evaluated. The plants Campomanesia xanthocarpa, Maytenus ilicifolia, Bidens pilosa and Verbena sp. showed the best activity against bacterial growth and biofilm formation. The majority of KPC-producing isolates, which showed strong ability to form biofilm and a multidrug resistance profile, was inhibited by more than 50% by some extracts. The Enterobacter cloacae (KPC 05) clinical isolate was the only one resistant to all extracts. This study confirms the importance of indigenous traditional medicinal knowledge and describes for the first time the ability of these plants to inhibit biofilm formation and/or bacterial growth of multi-drug resistant KPC-producing isolates. PMID:26749812

  16. 铜绿假单胞菌生物膜抑制药研究进展%Research progress on Pseudomonas aeruginosa biofilm inhibitor

    Institute of Scientific and Technical Information of China (English)

    王龙梓

    2011-01-01

    @@ 铜绿假单胞菌(Pseudomonas aeruginosa,PA)是常见的医院感染致病菌,其严重的耐药性与产生细菌生物膜(bacterial biofilm,BF)密切相关.藻酸盐是PA生物膜的主要组成成分.研究发现,抗菌药物等可对BF及其主要成分藻酸盐产生抑制作用.本文综述了近年来PA生物膜及其抑制药物的研究进展.

  17. In vitro biofilm forming capacity on abiotic contact surfaces by outbreak-associated Vibrio harveyi strains

    Institute of Scientific and Technical Information of China (English)

    Pallaval Veera Bramha Chari; Kuchipudi Viswadeepika; Bottu Anand Kumar

    2014-01-01

    Objective:To evaluate the in vitro biofilm forming capacity on abiotic food contact surfaces by Vibrio harveyi (V. harveyi) strains. Methods:Thirty six Gram-negative V. harveyi strains were isolated from various street vended seafood outlets in a food processing line and evaluated for their ability to produce mucoid biofilms on food contact surfaces using a microplate assay. Phenotypic characterization of mucoid biofilm producing V. harveyi strains were screened on Congo red agar, thiosulfate-citrate-bile salts-sucrose agar and tryptic soy agar, respectively. Results: Only five V. harveyi strains (14%) were mucoid biofilm producers characterized by formation of black colonies, whereas the remaining 31 strains (86%) were not capable of producing biofilm characterized by formation of red colonies or pinkish-red colonies with darkening at the centre. The morphological, physiological and biochemical characteristics of these isolates were studied using standard protocols. Strain identification was confirmed by polymerase chain reaction targeted to species-specific polymerase chain reaction primers VH-1 and VH-2 corresponding to variable regions of V. harveyi 16S rRNA sequence. All the biofilm-forming strains showed resistance to at least three antimicrobial compounds tested. V. harveyi strains isolated from various seafood were able to form biofilms of different capacity, and the strains VB267, VB238 and VB166 isolated from cat fish, shrimp and eel fish exhibited significantly greater biofilm forming ability compared to other isolates. Conclusions: It can be concluded from the present study that the strain VB166 was able to better attach and form subsequent biofilms on glass and stainless steel compared to high density polyethylene. These properties allow these bacteria to survive, proliferate and persist in street vended seafood outlets.

  18. In vitro biofilm forming capacity on abiotic contact surfaces by outbreak-associated Vibrio harveyi strains

    Directory of Open Access Journals (Sweden)

    Pallaval Veera Bramha Chari

    2014-02-01

    Full Text Available Objective: To evaluate the in vitro biofilm forming capacity on abiotic food contact surfaces by Vibrio harveyi (V. harveyi strains. Methods: Thirty six Gram-negative V. harveyi strains were isolated from various street vended seafood outlets in a food processing line and evaluated for their ability to produce mucoid biofilms on food contact surfaces using a microplate assay. Phenotypic characterization of mucoid biofilm producing V. harveyi strains were screened on Congo red agar, thiosulfate-citrate-bile salts-sucrose agar and tryptic soy agar, respectively. Results: Only five V. harveyi strains (14% were mucoid biofilm producers characterized by formation of black colonies, whereas the remaining 31 strains (86% were not capable of producing biofilm characterized by formation of red colonies or pinkish-red colonies with darkening at the centre. The morphological, physiological and biochemical characteristics of these isolates were studied using standard protocols. Strain identification was confirmed by polymerase chain reaction targeted to species-specific polymerase chain reaction primers VH-1 and VH-2 corresponding to variable regions of V. harveyi 16S rRNA sequence. All the biofilm-forming strains showed resistance to at least three antimicrobial compounds tested. V. harveyi strains isolated from various seafood were able to form biofilms of different capacity, and the strains VB267, VB238 and VB166 isolated from cat fish, shrimp and eel fish exhibited significantly greater biofilm forming ability compared to other isolates. Conclusions: It can be concluded from the present study that the strain VB166 was able to better attach and form subsequent biofilms on glass and stainless steel compared to high density polyethylene. These properties allow these bacteria to survive, proliferate and persist in street vended seafood outlets.

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

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, Peter Østrup; Burmølle, Mette;

    2005-01-01

    The opportunistic human pathogen Pseudomonas aeruginosa is the predominant micro-organism of chronic lung infections in cystic fibrosis (CF) patients. P. aeruginosa colonizes the CF lungs by forming biofilm structures in the alveoli. In the biofilm mode of growth the bacteria are highly tolerant to...... that biofilm bacteria in which QS is blocked either by mutation or by administration of QS inhibitory drugs are sensitive to treatment with tobramycin and H2O2, and are readily phagocytosed by PMNs, in contrast to bacteria with functional QS systems. In contrast to the wild-type, QS-deficient biofilms...

  20. The influence of oral Veillonella species on biofilms formed by Streptococcus species.

    Science.gov (United States)

    Mashima, Izumi; Nakazawa, Futoshi

    2014-08-01

    Oral Veillonella, Veillonella atypica, Veillonella denticariosi, Veillonella dispar, Veillonella parvula, Veillonella rogosae, and Veillonella tobetsuensis are known as early colonizers in oral biofilm formation. To investigate the role of oral Veillonella, biofilms formed by the co-culture of Streptococcus gordonii, Streptococcus mutans, Streptococcus salivarius, or Streptococcus sanguinis, with oral Veillonella were examined at the species level. The amount of biofilm formed by S. mutans, S. gordonii, and S. salivarius in the presence of the six Veillonella species was greater than that formed in the control experiments, with the exception of S. mutans with V. dispar. In contrast, in the case of biofilm formation by S. sanguinis, the presence of Veillonella species reduced the amount of the biofilm, with the exception of V. parvula and V. dispar. The time-dependent changes in the amount of biofilm and the number of planktonic cells were grouped into four patterns over the 24 combinations. Only that of S. gordonii with V. tobetsuensis showed a unique pattern. These results indicate that the mode of action of this combination differed from that of the other combinations with respect to biofilm formation. It is possible that there may be several factors involved in the interaction between Streptococcus and Veillonella species.

  1. Efficacy of a marine bacterial nuclease against biofilm forming microorganisms isolated from chronic rhinosinusitis.

    Directory of Open Access Journals (Sweden)

    Robert C Shields

    Full Text Available BACKGROUND: The persistent colonization of paranasal sinus mucosa by microbial biofilms is a major factor in the pathogenesis of chronic rhinosinusitis (CRS. Control of microorganisms within biofilms is hampered by the presence of viscous extracellular polymers of host or microbial origin, including nucleic acids. The aim of this study was to investigate the role of extracellular DNA in biofilm formation by bacteria associated with CRS. METHODS/PRINCIPAL FINDINGS: Obstructive mucin was collected from patients during functional endoscopic sinus surgery. Examination of the mucous by transmission electron microscopy revealed an acellular matrix punctuated occasionally with host cells in varying states of degradation. Bacteria were observed in biofilms on mucosal biopsies, and between two and six different species were isolated from each of 20 different patient samples. In total, 16 different bacterial genera were isolated, of which the most commonly identified organisms were coagulase-negative staphylococci, Staphylococcus aureus and α-haemolytic streptococci. Twenty-four fresh clinical isolates were selected for investigation of biofilm formation in vitro using a microplate model system. Biofilms formed by 14 strains, including all 9 extracellular nuclease-producing bacteria, were significantly disrupted by treatment with a novel bacterial deoxyribonuclease, NucB, isolated from a marine strain of Bacillus licheniformis. Extracellular biofilm matrix was observed in untreated samples but not in those treated with NucB and extracellular DNA was purified from in vitro biofilms. CONCLUSION/SIGNIFICANCE: Our data demonstrate that bacteria associated with CRS form robust biofilms which can be reduced by treatment with matrix-degrading enzymes such as NucB. The dispersal of bacterial biofilms with NucB may offer an additional therapeutic target for CRS sufferers.

  2. DKP对3株病原菌生物膜的抑制作用研究%Study on the Inhibition Effect of DKP on the Biofilms Formed by Three Pathogens

    Institute of Scientific and Technical Information of China (English)

    王建华; 权春善; 赵朋超; 范圣第

    2011-01-01

    The biofilms make it more difficult to treat the diseases caused by pathogens with antibiotics. A kind of diketopiperazine ( DKP )-cyclo ( Pro-Phe ) were found can inhibit the biofilms formation of Staphylococcus aureus,Pseudomonas aeruginosa and Candida albicans. The results of crystal violet staining,CFU (colony forming unit) analysis, and the structure analysis by optical microscope and atomic force microscope indicated that the biofilms of S. aureus and P. aeruginosa were almost disappeared with 10 mg/ml DKP,and the biofilms of C. albicans was significantly inhibited by 12 mg/ml DKP. This brings hope to the research work of novel biofilm inhibitors and cure of the biofilms-associated infections.%生物膜的存在使一些由病原菌引发的疾病变得更加难以治疗.经研究发现一种环二肽物质DKP-cyclo(Pro-Phe)能够抑制这3株病原菌(Staphylococcus aureus,Pseudomonas aeruginosa,Candida albicans)生物膜的形成.通过对不同浓度DKP作用下所形成的生物膜进行结晶紫定量、菌落计数分析和结构显微分析表明:在DKP的浓度达到10 mg/ml时,S.aureus和P.aeruginosa的生物膜几乎消失;在DKP的浓度达到12 mg/ml时,C.albicans的生物膜被显著抑制.这一发现为寻找新型的生物膜抑制剂治愈顽固疾病带来了新的希望.

  3. Effect of Mono and Di-rhamnolipids on Biofilms Pre-formed by Bacillus subtilis BBK006.

    Science.gov (United States)

    De Rienzo, Mayri A Díaz; Martin, Peter J

    2016-08-01

    Different microbial inhibition strategies based on the planktonic bacterial physiology have been known to have limited efficacy on the growth of biofilms communities. This problem can be exacerbated by the emergence of increasingly resistant clinical strains. Biosurfactants have merited renewed interest in both clinical and hygienic sectors due to their potential to disperse microbial biofilms. In this work, we explore the aspects of Bacillus subtilis BBK006 biofilms and examine the contribution of biologically derived surface-active agents (rhamnolipids) to the disruption or inhibition of microbial biofilms produced by Bacillus subtilis BBK006. The ability of mono-rhamnolipids (Rha-C10-C10) produced by Pseudomonas aeruginosa ATCC 9027 and the di-rhamnolipids (Rha-Rha-C14-C14) produced by Burkholderia thailandensis E264, and phosphate-buffered saline to disrupt biofilm of Bacillus subtilis BBK006 was evaluated. The biofilm produced by Bacillus subtilis BBK006 was more sensitive to the di-rhamnolipids (0.4 g/L) produced by Burkholderia thailandensis than the mono-rhamnolipids (0.4 g/L) produced by Pseudomonas aeruginosa ATCC 9027. Rhamnolipids are biologically produced compounds safe for human use. This makes them ideal candidates for use in new generations of bacterial dispersal agents and useful for use as adjuvants for existing microbial suppression or eradication strategies. PMID:27113589

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

    Science.gov (United States)

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

    2016-04-01

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

  5. Functional analysis of stress protein data in a flor yeast subjected to a biofilm forming condition

    OpenAIRE

    Moreno-García, Jaime; Mauricio, Juan Carlos; Moreno, Juan; García-Martínez, Teresa

    2016-01-01

    In this data article, an OFFGEL fractionator coupled to LTQ Orbitrap XL MS equipment and a SGD filtering were used to detect in a biofilm-forming flor yeast strain, the maximum possible number of stress proteins under the first stage of a biofilm formation conditions (BFC) and under an initial stage of fermentation used as reference, so-called non-biofilm formation condition (NBFC). Protein functional analysis – based on cellular components and biological process GO terms – was performed for ...

  6. Extracellular electron transfer mechanism in Shewanella loihica PV-4 biofilms formed at indium tin oxide and graphite electrodes

    Digital Repository Service at National Institute of Oceanography (India)

    Jain, A.; Connolly, J.O.; Woolley, R.; Krishnamurthy, S.; Marsili, E.

    at the biofilm/ITO interface, while biofilms formed at graphite electrode reduced the electrode also via secreted redox mediators, such as flavins and quinones. The biofilm age does not affect the prevalent transfer mechanism at ITO electrodes. On the other hand...

  7. Characterizing Pilus-Mediated Adhesion of Biofilm-Forming E. coli to Chemically Diverse Surfaces Using Atomic Force Microscopy

    OpenAIRE

    Xu, He; Murdaugh, Anne E.; Chen, Wei; Aidala, Katherine E.; Ferguson, Megan A.; Spain, Eileen M.; Núñez, Megan E.

    2013-01-01

    Biofilms are complex communities of microorganisms living together at an interface. Because biofilms are often associated with contamination and infection, it is critical to understand how bacterial cells adhere to surfaces in the early stages of biofilm formation. Even harmless commensal Escherichia coli naturally forms biofilms in the human digestive tract by adhering to epithelial cells, a trait that presents major concerns in the case of pathogenic E. coli strains. The laboratory strain E...

  8. Acquisition and role of molybdate in Pseudomonas aeruginosa.

    Science.gov (United States)

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

    2014-11-01

    In microaerophilic or anaerobic environments, Pseudomonas aeruginosa utilizes nitrate reduction for energy production, a process dependent on the availability of the oxyanionic form of molybdenum, molybdate (MoO4 (2-)). Here, we show that molybdate acquisition in P. aeruginosa occurs via a high-affinity ATP-binding cassette permease (ModABC). ModA is a cluster D-III solute binding protein capable of interacting with molybdate or tungstate oxyanions. Deletion of the modA gene reduces cellular molybdate concentrations and results in inhibition of anaerobic growth and nitrate reduction. Further, we show that conditions that permit nitrate reduction also cause inhibition of biofilm formation and an alteration in fatty acid composition of P. aeruginosa. Collectively, these data highlight the importance of molybdate for anaerobic growth of P. aeruginosa and reveal novel consequences of nitrate reduction on biofilm formation and cell membrane composition. PMID:25172858

  9. Acquisition and role of molybdate in Pseudomonas aeruginosa.

    Science.gov (United States)

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

    2014-11-01

    In microaerophilic or anaerobic environments, Pseudomonas aeruginosa utilizes nitrate reduction for energy production, a process dependent on the availability of the oxyanionic form of molybdenum, molybdate (MoO4 (2-)). Here, we show that molybdate acquisition in P. aeruginosa occurs via a high-affinity ATP-binding cassette permease (ModABC). ModA is a cluster D-III solute binding protein capable of interacting with molybdate or tungstate oxyanions. Deletion of the modA gene reduces cellular molybdate concentrations and results in inhibition of anaerobic growth and nitrate reduction. Further, we show that conditions that permit nitrate reduction also cause inhibition of biofilm formation and an alteration in fatty acid composition of P. aeruginosa. Collectively, these data highlight the importance of molybdate for anaerobic growth of P. aeruginosa and reveal novel consequences of nitrate reduction on biofilm formation and cell membrane composition.

  10. The Hybrid Histidine Kinase LadS Forms a Multicomponent Signal Transduction System with the GacS/GacA Two-Component System in Pseudomonas aeruginosa

    Science.gov (United States)

    Redelberger, David; Fadel, Firas; Filloux, Alain; Sivaneson, Melissa; de Bentzmann, Sophie; Bordi, Christophe

    2016-01-01

    In response to environmental changes, Pseudomonas aeruginosa is able to switch from a planktonic (free swimming) to a sessile (biofilm) lifestyle. The two-component system (TCS) GacS/GacA activates the production of two small non-coding RNAs, RsmY and RsmZ, but four histidine kinases (HKs), RetS, GacS, LadS and PA1611, are instrumental in this process. RetS hybrid HK blocks GacS unorthodox HK autophosphorylation through the formation of a heterodimer. PA1611 hybrid HK, which is structurally related to GacS, interacts with RetS in P. aeruginosa in a very similar manner to GacS. LadS hybrid HK phenotypically antagonizes the function of RetS by a mechanism that has never been investigated. The four sensors are found in most Pseudomonas species but their characteristics and mode of signaling may differ from one species to another. Here, we demonstrated in P. aeruginosa that LadS controls both rsmY and rsmZ gene expression and that this regulation occurs through the GacS/GacA TCS. We additionally evidenced that in contrast to RetS, LadS signals through GacS/GacA without forming heterodimers, either with GacS or with RetS. Instead, we demonstrated that LadS is involved in a genuine phosphorelay, which requires both transmitter and receiver LadS domains. LadS signaling ultimately requires the alternative histidine-phosphotransfer domain of GacS, which is here used as an Hpt relay by the hybrid kinase. LadS HK thus forms, with the GacS/GacA TCS, a multicomponent signal transduction system with an original phosphorelay cascade, i.e. H1LadS→D1LadS→H2GacS→D2GacA. This highlights an original strategy in which a unique output, i.e. the modulation of sRNA levels, is controlled by a complex multi-sensing network to fine-tune an adapted biofilm and virulence response. PMID:27176226

  11. The Role of Biofilms in the Sedimentology of Actively Forming Gypsum Deposits at Guerrero Negro, Mexico

    Science.gov (United States)

    Vogel, Marilyn B.; Des Marais, David J.; Turk, Kendra A.; Parenteau, Mary N.; Jahnke, Linda L.; Kubo, Michael D. Y.

    2009-11-01

    Actively forming gypsum deposits at the Guerrero Negro sabkha and saltern system provided habitats for stratified, pigmented microbial communities that exhibited significant morphological and phylogenetic diversity. These deposits ranged from meter-thick gypsum crusts forming in saltern seawater concentration ponds to columnar microbial mats with internally crystallized gypsum granules developing in natural anchialine pools. Gypsum-depositing environments were categorized as forming precipitation surfaces, biofilm-supported surfaces, and clastic surfaces. Each surface type was described in terms of depositional environment, microbial diversity, mineralogy, and sedimentary fabrics. Precipitation surfaces developed in high-salinity subaqueous environments where rates of precipitation outpaced the accumulation of clastic, organic, and/or biofilm layers. These surfaces hosted endolithic biofilms comprised predominantly of oxygenic and anoxygenic phototrophs, sulfate-reducing bacteria, and bacteria from the phylum Bacteroidetes. Biofilm-supported deposits developed in lower-salinity subaqueous environments where light and low water-column turbulence supported dense benthic microbial communities comprised mainly of oxygenic phototrophs. In these settings, gypsum granules precipitated in the extracellular polymeric substance (EPS) matrix as individual granules exhibiting distinctive morphologies. Clastic surfaces developed in sabkha mudflats that included gypsum, carbonate, and siliclastic particles with thin gypsum/biofilm components. Clastic surfaces were influenced by subsurface brine sheets and capillary evaporation and precipitated subsedimentary gypsum discs in deeper regions. Biofilms appeared to influence both chemical and physical sedimentary processes in the various subaqueous and subaerially exposed environments studied. Biofilm interaction with chemical sedimentary processes included dissolution and granularization of precipitation surfaces, formation of

  12. Biofilm forming and leaching mechanism during bioleaching chalcopyrite by Thiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    傅建华; 胡岳华; 邱冠周; 柳建设; 徐竞

    2004-01-01

    The mechanism of attachment and leaching of thiobacillus ferrooxcidans (T. f. ) on chalcopyrite were studied. The shaking flasks with bacteria were observed by SEM. The process of T. f attached to the surface of the mineral sample and the biofilm forming were described. The promoting role of the biofilm for bioleaching was discussed. The existence of Fe2+ in the exopolysaccharide layer of T. f was demonstrated by EM(electronic microscope)cell-chemistry analysis. These results show that under the proper growth condition of bacteria, bioleaching of chalcopyrite results in the formation of complete biofilm after 2 - 3 weeks. There are iron ions in the outer layer polymer of T. f. , which provides the micro-environment for themselves, and can guaruntee the energy needed for the bacteria growth in the biofilm. At the same time, Fe3+ ions produced oxidize sulfide which brings about the increase of both growth rate of the bacterial and leaching rate of sulfide minerals.

  13. Functional analysis of stress protein data in a flor yeast subjected to a biofilm forming condition.

    Science.gov (United States)

    Moreno-García, Jaime; Mauricio, Juan Carlos; Moreno, Juan; García-Martínez, Teresa

    2016-06-01

    In this data article, an OFFGEL fractionator coupled to LTQ Orbitrap XL MS equipment and a SGD filtering were used to detect in a biofilm-forming flor yeast strain, the maximum possible number of stress proteins under the first stage of a biofilm formation conditions (BFC) and under an initial stage of fermentation used as reference, so-called non-biofilm formation condition (NBFC). Protein functional analysis - based on cellular components and biological process GO terms - was performed for these proteins through the SGD Gene Ontology Slim Mapper tool. A detailed analysis and interpretation of the data can be found in "Stress responsive proteins of a flor yeast strain during the early stages of biofilm formation" [1]. PMID:27104213

  14. Functional analysis of stress protein data in a flor yeast subjected to a biofilm forming condition

    Directory of Open Access Journals (Sweden)

    Jaime Moreno-García

    2016-06-01

    Full Text Available In this data article, an OFFGEL fractionator coupled to LTQ Orbitrap XL MS equipment and a SGD filtering were used to detect in a biofilm-forming flor yeast strain, the maximum possible number of stress proteins under the first stage of a biofilm formation conditions (BFC and under an initial stage of fermentation used as reference, so-called non-biofilm formation condition (NBFC. Protein functional analysis – based on cellular components and biological process GO terms – was performed for these proteins through the SGD Gene Ontology Slim Mapper tool. A detailed analysis and interpretation of the data can be found in “Stress responsive proteins of a flor yeast strain during the early stages of biofilm formation” [1].

  15. Functional analysis of stress protein data in a flor yeast subjected to a biofilm forming condition

    Science.gov (United States)

    Moreno-García, Jaime; Mauricio, Juan Carlos; Moreno, Juan; García-Martínez, Teresa

    2016-01-01

    In this data article, an OFFGEL fractionator coupled to LTQ Orbitrap XL MS equipment and a SGD filtering were used to detect in a biofilm-forming flor yeast strain, the maximum possible number of stress proteins under the first stage of a biofilm formation conditions (BFC) and under an initial stage of fermentation used as reference, so-called non-biofilm formation condition (NBFC). Protein functional analysis – based on cellular components and biological process GO terms – was performed for these proteins through the SGD Gene Ontology Slim Mapper tool. A detailed analysis and interpretation of the data can be found in “Stress responsive proteins of a flor yeast strain during the early stages of biofilm formation” [1]. PMID:27104213

  16. Biofilm-Forming Capacity in Biogenic Amine-Producing Bacteria Isolated from Dairy Products

    Science.gov (United States)

    Diaz, Maria; Ladero, Victor; del Rio, Beatriz; Redruello, Begoña; Fernández, María; Martin, M. Cruz; Alvarez, Miguel A.

    2016-01-01

    Biofilms on the surface of food industry equipment are reservoirs of potentially food-contaminating bacteria—both spoilage and pathogenic. However, the capacity of biogenic amine (BA)-producers to form biofilms has remained largely unexamined. BAs are low molecular weight, biologically active compounds that in food can reach concentrations high enough to be a toxicological hazard. Fermented foods, especially some types of cheese, accumulate the highest BA concentrations of all. The present work examines the biofilm-forming capacity of 56 BA-producing strains belonging to three genera and 10 species (12 Enterococcus faecalis, 6 Enterococcus faecium, 6 Enterococcus durans, 1 Enterococcus hirae, 12 Lactococcus lactis, 7 Lactobacillus vaginalis, 2 Lactobacillus curvatus, 2 Lactobacillus brevis, 1 Lactobacillus reuteri, and 7 Lactobacillus parabuchneri), all isolated from dairy products. Strains of all the tested species - except for L. vaginalis—were able to produce biofilms on polystyrene and adhered to stainless steel. However, the biomass produced in biofilms was strain-dependent. These results suggest that biofilms may provide a route via which fermented foods can become contaminated by BA-producing microorganisms. PMID:27242675

  17. Biofilm-forming capacity in biogenic amine-producing bacteria isolated from dairy products.

    Directory of Open Access Journals (Sweden)

    Maria eDiaz

    2016-05-01

    Full Text Available Biofilms on the surface of food industry equipment are reservoirs of potentially food-contaminating bacteria - both spoilage and pathogenic. However, the capacity of biogenic amine (BA-producers to form biofilms has remained largely unexamined. BAs are low molecular weight, biologically active compounds that in food can reach concentrations high enough to be a toxicological hazard. Fermented foods, especially some types of cheese, accumulate the highest BA concentrations of all. The present work examines the biofilm-forming capacity of 56 BA-producing strains belonging to three genera and 10 species (12 Enterococcus faecalis, 6 Enterococcus faecium, 6 Enterococcus durans, 1 Enterococcus hirae, 12 Lactococcus lactis, 7 Lactobacillus vaginalis, 2 Lactobacillus curvatus, 2 Lactobacillus brevis, 1 Lactobacillus reuteri and 7 Lactobacillus parabuchneri, all isolated from dairy products. Strains of all the tested species - except for L. vaginalis - were able to produce biofilms on polystyrene and adhered to stainless steel. However, the biomass produced in biofilms was strain-dependent. These results suggest that biofilms may provide a route via which fermented foods can become contaminated by BA-producing microorganisms.

  18. Anti-biofilm activities from marine cold adapted bacteria against Staphylococci and Pseudomonas aeruginosa

    OpenAIRE

    Papa, R.; Selan, L.; Parrilli, E.; Tilotta, M.; Sannino, F.; Feller, G.; Tutino, M; Artini, M

    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 bacte...

  19. Potential novel therapeutic strategies in cystic fibrosis: antimicrobial and anti-biofilm activity of natural and designed α-helical peptides against Staphylococcus aureus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia

    Directory of Open Access Journals (Sweden)

    Pompilio Arianna

    2012-07-01

    Full Text Available Abstract Background Treatment of cystic fibrosis-associated lung infections is hampered by the presence of multi-drug resistant pathogens, many of which are also strong biofilm producers. Antimicrobial peptides, essential components of innate immunity in humans and animals, exhibit relevant in vitro antimicrobial activity although they tend not to select for resistant strains. Results Three α-helical antimicrobial peptides, BMAP-27 and BMAP-28 of bovine origin, and the artificial P19(9/B peptide were tested, comparatively to Tobramycin, for their in vitro antibacterial and anti-biofilm activity against 15 Staphylococcus aureus, 25 Pseudomonas aeruginosa, and 27 Stenotrophomonas maltophilia strains from cystic fibrosis patients. All assays were carried out in physical-chemical experimental conditions simulating a cystic fibrosis lung. All peptides showed a potent and rapid bactericidal activity against most P. aeruginosa, S. maltophilia and S. aureus strains tested, at levels generally higher than those exhibited by Tobramycin and significantly reduced biofilm formation of all the bacterial species tested, although less effectively than Tobramycin did. On the contrary, the viability-reducing activity of antimicrobial peptides against preformed P. aeruginosa biofilms was comparable to and, in some cases, higher than that showed by Tobramycin. Conclusions The activity shown by α-helical peptides against planktonic and biofilm cells makes them promising “lead compounds” for future development of novel drugs for therapeutic treatment of cystic fibrosis lung disease.

  20. The effect of biyuanshu oral liquid on the formation of pseudomonas aeruginosa biofilms in vitro%鼻渊舒口服液对铜绿假单胞菌生物膜体外形成的抑制作用

    Institute of Scientific and Technical Information of China (English)

    刘向; 陈海红; 汪审清

    2012-01-01

    目的:观察鼻渊舒口服液对铜绿假单胞菌生物膜体外形成的抑制作用.方法:平板法建立铜绿假单胞菌细菌生物膜体外模型,银染法及扫描电子显微镜鉴定.不同浓度的鼻渊舒口服液及红霉素作用于成熟前阶段的及已形成的铜绿假单胞菌生物膜,银染法及连续稀释法菌落计数观察其对生物膜的抑制作用.结果:扫描电镜观察铜绿假单胞菌在硅胶片上7d形成生物膜,与银染结果一致.红霉素及鼻渊舒体外能抑制铜绿假单胞菌生物膜的形成,且抑制作用随药物浓度的增加而加强,但对已形成的细菌生物膜清除作用不明显.连续稀释法菌落计数结果表明,不同浓度红霉素及鼻渊舒能抑制成熟前的生物膜膜内细菌生长,与对照组比较差异有统计学意义(P<0.05).结论:鼻渊舒口服液及红霉素体外对铜绿假单胞菌生物膜的形成有抑制作用.%Objective:To observe the effect of biyuanshu oral liquid on the formation of pseudomonas aeruginosa biofilms in vitro. Method: Pseudomonas aeruginosa biofilm was established by plate culture and detected by Scanning electron microscopy and AgNO3 stainning . After treated with different dosages of biyuanshu oral liquid and erythromycin, the pseudomonas aeruginosa biofilms were observed by AgNO3 stainning and the number of viable bacteria were measured by serial dilution. Result; The pseudomonas aeruginosa biofilms could be detected by SEM at the seventh culture day and it was consistent with the detetion of AgNO3 stainning. The biyuanshu oral liquid and erythromycin have the effect on inhibiting the formation of pseudomonas aeruginosa biofilms. But with the already formed pseudomonas aeruginosa biofilms the inhibition was not significant. The serial dilution method showed that the viable counts of bacteria of biyuanshu oral liquid and erythromycin treated groups were significantly lower than those untreated groups(P<0. 05). Conclusion

  1. Influence of Amphibian Antimicrobial Peptides and Short Lipopeptides on Bacterial Biofilms Formed on Contact Lenses

    Directory of Open Access Journals (Sweden)

    Magdalena Maciejewska

    2016-10-01

    Full Text Available The widespread use of contact lenses is associated with several complications, including ocular biofilm-related infections. They are very difficult to manage with standard antimicrobial therapies, because bacterial growth in a biofilm is associated with an increased antibiotic resistance. The principal aim of this study was to evaluate the efficacy of antimicrobial peptides (AMPs in eradication of bacterial biofilms formed on commercially available contact lenses. AMPs were synthesized according to Fmoc/tBu chemistry using the solid-phase method. Minimum inhibitory concentration (MIC and minimum biofilm eradication concentration (MBEC of the compounds were determined. Anti-biofilm activity of the antimicrobial peptides determined at different temperatures (25 °C and 37 °C were compared with the effectiveness of commercially available contact lens solutions. All of the tested compounds exhibited stronger anti-biofilm properties as compared to those of the tested lens solutions. The strongest activity of AMPs was noticed against Gram-positive strains at a temperature of 25 °C. Conclusions: The results of our experiments encourage us toward further studies on AMPs and their potential application in the prophylaxis of contact lens-related eye infections.

  2. Macroscale versus microscale methods for physiological analysis of biofilms formed in 96-well microtiter plates.

    Science.gov (United States)

    Gomes, L C; Moreira, J M R; Miranda, J M; Simões, M; Melo, L F; Mergulhão, F J

    2013-12-01

    Microtiter plates with 96 wells have become one of the preferred platforms for biofilm studies mainly because they enable high-throughput assays. In this work, macroscale and microscale methods were used to study the impact of hydrodynamic conditions on the physiology and location of Escherichia coli JM109(DE3) biofilms formed in microtiter plates. Biofilms were formed in shaking and static conditions, and two macroscale parameters were assayed: the total amount of biofilm was measured by the crystal violet assay and the metabolic activity was determined by the resazurin assay. From the macroscale point of view, there were no statistically significant differences between the biofilms formed in static and shaking conditions. However, at a microscale level, the differences between both conditions were revealed using scanning electron microscopy (SEM). It was observed that biofilm morphology and spatial distribution along the wall were different in these conditions. Simulation of the hydrodynamic conditions inside the wells at a microscale was performed by computational fluid dynamics (CFD). These simulations showed that the shear strain rate was unevenly distributed on the walls during shaking conditions and that regions of higher shear strain rate were obtained closer to the air/liquid interface. Additionally, it was shown that wall regions subjected to higher shear strain rates were associated with the formation of biofilms containing cells of smaller size. Conversely, regions with lower shear strain rate were prone to have a more uniform spatial distribution of adhered cells of larger size. The results presented on this work highlight the wealth of information that may be gathered by complementing macroscale approaches with a microscale analysis of the experiments. PMID:24140575

  3. The efficacy of immediate versus delayed antibiotic administration on bacterial growth and biofilm production of selected strains of uropathogenic Escherichia coli and Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Leah Gandee

    2015-02-01

    Full Text Available Purpose The treatment of urinary tract infections (UTI with antibiotics is commonly used, but recurrence and antibiotic resistance have been growing and concerning clinicians. We studied whether the rapid onset of a protective biofilm may be responsible for the lack of effectiveness of antibiotics against selected bacteria. Materials and Methods Two established uropathogenic Escherichia coli strains, UTI89 and CFT073, and two Pseudomonas aeruginosa strains, PA01 and Boston-41501, were studied to establish a reliable biofilm formation process. Bacterial growth (BG was determined by optical density at 600 nm (OD 600 using a spectrophotometer, while biofilm formation (BF using crystal violet staining was measured at OD 550. Next, these bacterial strains were treated with clinically relevant antibiotics, ciprofloxacin HCl (200 ng/mL and 2 μg/mL, nitrofurantoin (20 μg/mL and 40 μg/mL and ampicillin (50 μg/mL at time points of 0 (T0 or after 6 hours of culture (T6. All measurements, including controls (bacteria -1% DMSO, were done in triplicates and repeated three times for consistency. Results The tested antibiotics effectively inhibited both BG and BF when administered at T0 for UPEC strains, but not when the antibiotic administration started 6 hours later. For Pseudomonas strains, only Ciprofloxacin was able to significantly inhibit bacterial growth at T0 but only at the higher concentration of 2 μg/mL for T6. Conclusion When established UPEC and Pseudomonas bacteria were allowed to culture for 6 hours before initialization of treatment, the therapeutic effect of selected antibiotics was greatly suppressed when compared to immediate treatment, probably as a result of the protective nature of the biofilm.

  4. Comparative genomics reveals diversified CRISPR-Cas systems of globally distributed Microcystis aeruginosa, a freshwater bloom-forming cyanobacterium

    Directory of Open Access Journals (Sweden)

    Chen eYang

    2015-05-01

    Full Text Available Microcystis aeruginosa is one of the most common and dominant bloom-forming cyanobacteria in freshwater lakes around the world. Microcystis cells can produce toxic secondary metabolites, such as microcystins, which are harmful to human health. Two M. aeruginosa strains were isolated from two highly eutrophic lakes in China and their genomes were sequenced. Comparative genomic analysis was performed with the 12 other available M. aeruginosa genomes and closely related unicellular cyanobacterium. Each genome of M. aeruginosa containing at least one clustered regularly interspaced short palindromic repeat (CRISPR locus and total 71 loci were identified, suggesting it is ubiquitous in M. aeruginosa genomes. In addition to the previously reported subtype I-D cas gene sets, three CAS subtypes I-A, III-A and III-B were identified and characterized in this study. Seven types of CRISPR direct repeat have close association with CAS subtype, confirming that different and specific secondary structures of CRISPR repeats are important for the recognition, binding and process of corresponding cas gene sets. Homology search of the CRISPR spacer sequences provides a history of not only resistance to bacteriophages and plasmids known to be associated with M. aeruginosa, but also the ability to target much more exogenous genetic material in the natural environment. These adaptive and heritable defense mechanisms play a vital role in keeping genomic stability and self-maintenance by restriction of horizontal gene transfer. Maintaining genomic stability and modulating genomic plasticity are both important evolutionary strategies for M. aeruginosa in adaptation and survival in various habitats.

  5. The absence of the Pseudomonas aeruginosa OprF protein leads to increased biofilm formation through variation in c-di-GMP level.

    Science.gov (United States)

    Bouffartigues, Emeline; Moscoso, Joana A; Duchesne, Rachel; Rosay, Thibaut; Fito-Boncompte, Laurène; Gicquel, Gwendoline; Maillot, Olivier; Bénard, Magalie; Bazire, Alexis; Brenner-Weiss, Gerald; Lesouhaitier, Olivier; Lerouge, Patrice; Dufour, Alain; Orange, Nicole; Feuilloley, Marc G J; Overhage, Joerg; Filloux, Alain; Chevalier, Sylvie

    2015-01-01

    OprF is the major outer membrane porin in bacteria belonging to the Pseudomonas genus. In previous studies, we have shown that OprF is required for full virulence expression of the opportunistic pathogen Pseudomonas aeruginosa. Here, we describe molecular insights on the nature of this relationship and report that the absence of OprF leads to increased biofilm formation and production of the Pel exopolysaccharide. Accordingly, the level of c-di-GMP, a key second messenger in biofilm control, is elevated in an oprF mutant. By decreasing c-di-GMP levels in this mutant, both biofilm formation and pel gene expression phenotypes were restored to wild-type levels. We further investigated the impact on two small RNAs, which are associated with the biofilm lifestyle, and found that expression of rsmZ but not of rsmY was increased in the oprF mutant and this occurs in a c-di-GMP-dependent manner. Finally, the extracytoplasmic function (ECF) sigma factors AlgU and SigX displayed higher activity levels in the oprF mutant. Two genes of the SigX regulon involved in c-di-GMP metabolism, PA1181 and adcA (PA4843), were up-regulated in the oprF mutant, partly explaining the increased c-di-GMP level. We hypothesized that the absence of OprF leads to a cell envelope stress that activates SigX and results in a c-di-GMP elevated level due to higher expression of adcA and PA1181. The c-di-GMP level can in turn stimulate Pel synthesis via increased rsmZ sRNA levels and pel mRNA, thus affecting Pel-dependent phenotypes such as cell aggregation and biofilm formation. This work highlights the connection between OprF and c-di-GMP regulatory networks, likely via SigX (ECF), on the regulation of biofilm phenotypes.

  6. The absence of the Pseudomonas aeruginosa OprF protein leads to increased biofilm formation through variation in c-di-GMP level

    Directory of Open Access Journals (Sweden)

    Emeline eBouffartigues

    2015-06-01

    Full Text Available OprF is the major outer membrane porin in bacteria belonging to the Pseudomonas genus. In previous studies, we have shown that OprF is required for full virulence expression of the opportunistic pathogen Pseudomonas aeruginosa. Here, we describe molecular insights on the nature of this relationship and report that the absence of OprF leads to increased biofilm formation and production of the Pel exopolysaccharide. Accordingly, the level of c-di-GMP, a key second messenger in biofilm control, is elevated in an oprF mutant. By decreasing c-di-GMP levels in this mutant, both biofilm formation and pel gene expression phenotypes were restored to wild-type levels. We further investigated the impact on two small RNAs, which are associated with the biofilm lifestyle, and found that expression of rsmZ but not of rsmY was increased in the oprF mutant and this occurs in a c-di-GMP-dependent manner. Finally, the extracytoplasmic function (ECF sigma factors AlgU and SigX displayed higher activity levels in the oprF mutant. Two genes of the SigX regulon involved in c-di-GMP metabolism, PA1181 and adcA (PA4843, were up-regulated in the oprF mutant, partly explaining the increased c-di-GMP level. We hypothesized that the absence of OprF leads to a cell envelope stress that activates SigX and results in a c-di-GMP elevated level due to higher expression of adcA and PA1181. The c-di-GMP level can in turn stimulate Pel synthesis via increased rsmZ sRNA levels and pel mRNA, thus affecting Pel-dependent phenotypes such as cell aggregation and biofilm formation. This work highlights the connection between OprF and c-di-GMP regulatory networks, likely via SigX (ECF, on the regulation of biofilm phenotypes.

  7. Frequency of biofilm formation in toothbrushes and wash basin junks

    Directory of Open Access Journals (Sweden)

    Abdulazeez A Abubakar

    2013-01-01

    Full Text Available Background: Biofilms are known to be resistant to several antibiotics once they are allowed to form on any surface. Aim: To investigate the biofilm forming ability of some bacterial isolates in toothbrushes and wash basin junks. Materials and Methods: A total of 606 students of Federal University of Technology, Yola were provided with new toothbrushes, which were collected after 1 month of usage and screened for biofilm formation. Another 620 swabs were collected from the wash basins of Federal Medical Centre, Specialist Hospital, Federal University of Technology, and students′ hostels in Yola and from some residence in Jimeta, Yola Metropolis; they were all screened for biofilm formation. Results: A total of 38.3% biofilm formation rate was recorded. Three types of bacterial isolates were identified in the biofilms of toothbrushes and wash basin junks, namely Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa at the prevalence rate of 48.0%, 29.1%, and 22.6%, respectively. Overall, 83.3% of the toothbrush biofilm were identified from female students, while 16.7% were from their male counterparts. Statistically, the frequency of biofilm formation showed a significant difference by gender (X 2 = 10.242, P 0.05. Conclusion: This study identified three microorganisms namely S. aureus, E. coli, and P. aeruginosa that were involved in wash basin junk biofilm formation. The findings also showed that occurrence of biofilm in females′ toothbrushes were significantly higher than in males′ (X 2 = 10.242, P < 0.05.

  8. Dynamic remodeling of microbial biofilms by functionally distinct exopolysaccharides.

    Science.gov (United States)

    Chew, Su Chuen; Kundukad, Binu; Seviour, Thomas; van der Maarel, Johan R C; Yang, Liang; Rice, Scott A; Doyle, Patrick; Kjelleberg, Staffan

    2014-08-05

    Biofilms are densely populated communities of microbial cells protected and held together by a matrix of extracellular polymeric substances. The structure and rheological properties of the matrix at the microscale influence the retention and transport of molecules and cells in the biofilm, thereby dictating population and community behavior. Despite its importance, quantitative descriptions of the matrix microstructure and microrheology are limited. Here, particle-tracking microrheology in combination with genetic approaches was used to spatially and temporally study the rheological contributions of the major exopolysaccharides Pel and Psl in Pseudomonas aeruginosa biofilms. Psl increased the elasticity and effective cross-linking within the matrix, which strengthened its scaffold and appeared to facilitate the formation of microcolonies. Conversely, Pel reduced effective cross-linking within the matrix. Without Psl, the matrix becomes more viscous, which facilitates biofilm spreading. The wild-type biofilm decreased in effective cross-linking over time, which would be advantageous for the spreading and colonization of new surfaces. This suggests that there are regulatory mechanisms to control production of the exopolysaccharides that serve to remodel the matrix of developing biofilms. The exopolysaccharides were also found to have profound effects on the spatial organization and integration of P. aeruginosa in a mixed-species biofilm model of P. aeruginosa-Staphylococcus aureus. Pel was required for close association of the two species in mixed-species microcolonies. In contrast, Psl was important for P. aeruginosa to form single-species biofilms on top of S. aureus biofilms. Our results demonstrate that Pel and Psl have distinct physical properties and functional roles during biofilm formation. Importance: Most bacteria grow as biofilms in the environment or in association with eukaryotic hosts. Removal of biofilms that form on surfaces is a challenge in clinical

  9. Silver colloidal nanoparticle stability: influence on Candida biofilms formed on denture acrylic.

    Science.gov (United States)

    Monteiro, Douglas Roberto; Takamiya, Aline Satie; Feresin, Leonardo Perina; Gorup, Luiz Fernando; de Camargo, Emerson Rodrigues; Delbem, Alberto Carlos Botazzo; Henriques, Mariana; Barbosa, Debora Barros

    2014-08-01

    Our aim in this study was to evaluate how the chemical stability of silver nanoparticles (SNs) influences their efficacy against Candida albicans and C. glabrata biofilms. Several parameters of SN stability were tested, namely, temperature (50ºC, 70ºC, and 100ºC), pH (5.0 and 9.0), and time of contact (5 h and 24 h) with biofilms. The control was defined as SNs without temperature treatment, pH 7, and 24 h of contact. These colloidal suspensions at 54 mg/L were used to treat mature Candida biofilms (48 h) formed on acrylic. Their efficacy was determined by total biomass and colony-forming unit quantification. Data were analyzed using analysis of variance and the Bonferroni post hoc test (α = 0.05). The temperature and pH variations of SNs did not affect their efficacy against the viable cells of Candida biofilms (P > 0.05). Moreover, the treatment periods were not decisive in terms of the susceptibility of Candida biofilms to SNs. These findings provide an important advantage of SNs that may be useful in the treatment of Candida-associated denture stomatitis.

  10. Antibiofilm activity of α-amylase from Bacillus subtilis S8-18 against biofilm forming human bacterial pathogens.

    Science.gov (United States)

    Kalpana, Balu Jancy; Aarthy, Subramonian; Pandian, Shunmugiah Karutha

    2012-07-01

    The extracellular α-amylase enzyme from Bacillus subtilis S8-18 of marine origin was proved as an antibiofilm agent against methicillin-resistant Staphylococcus aureus (MRSA), a clinical strain isolated from pharyngitis patient, Vibrio cholerae also a clinical isolate from cholera patient and Pseudomonas aeruginosa ATCC10145. The spectrophotometric and microscopic investigations revealed the potential of α-amylase to inhibit biofilm formation in these pathogens. At its BIC level, the crude enzyme caused 51.81-73.07% of biofilm inhibition. Beyond the inhibition, the enzyme was also effective in degradation of preformed mature biofilm by disrupting the exopolysaccharide (EPS), an essential component in biofilm architecture. Furthermore, the enzyme purified to its homogeneity by chromatographic techniques was also effective in biofilm inhibition (43.83-61.68%) as well as in degradation of EPS. A commercial α-amylase enzyme from B. subtilis was also used for comparative purpose. Besides, the effect of various enzymes and temperature on the antibiofilm activity of amylase enzymes was also investigated. This study, for the first time, proved that α-amylase enzyme alone can be used to inhibit/disrupt the biofilms of V. cholerae and MRSA strains and beholds much promise in clinical applications.

  11. The Pseudomonas aeruginosa CreBC two-component system plays a major role in the response to β-lactams, fitness, biofilm growth, and global regulation.

    Science.gov (United States)

    Zamorano, Laura; Moyà, Bartolomé; Juan, Carlos; Mulet, Xavier; Blázquez, Jesús; Oliver, Antonio

    2014-09-01

    Pseudomonas aeruginosa is a ubiquitous versatile environmental microorganism with a remarkable ability to grow under diverse environmental conditions. Moreover, P. aeruginosa is responsible for life-threatening infections in immunocompromised and cystic fibrosis patients, as the extraordinary capacity of this pathogen to develop antimicrobial resistance dramatically limits our therapeutic arsenal. Its large genome carries an outstanding number of genes belonging to regulatory systems, including multiple two-component sensor-regulator systems that modulate the response to the different environmental stimuli. Here, we show that one of two systems, designated CreBC (carbon source responsive) and BlrAB (β-lactam resistance), might be of particular relevance. We first identified the stimuli triggering the activation of the CreBC system, which specifically responds to penicillin-binding protein 4 (PBP4) inhibition by certain β-lactam antibiotics. Second, through an analysis of a large comprehensive collection of mutants, we demonstrate an intricate interconnection between the CreBC system, the peptidoglycan recycling pathway, and the expression of the concerning chromosomal β-lactamase AmpC. Third, we show that the CreBC system, and particularly its effector inner membrane protein CreD, plays a major role in bacterial fitness and biofilm development, especially in the presence of subinhibitory concentrations of β-lactams. Finally, global transcriptomics reveals broad regulatory functions of CreBC in basic physiological aspects, particularly anaerobic respiration, in both the presence and absence of antibiotics. Therefore, the CreBC system is envisaged as a potentially interesting target for improving the efficacy of β-lactams against P. aeruginosa infections. PMID:24936599

  12. Effect of Cinnamon Oil on Quorum Sensing-Controlled Virulence Factors and Biofilm Formation in Pseudomonas aeruginosa

    OpenAIRE

    Manmohit Kalia; Vivek Kumar Yadav; Pradeep Kumar Singh; Deepmala Sharma; Himanshu Pandey; Shahid Suhail Narvi; Vishnu Agarwal

    2015-01-01

    Quorum sensing (QS) is a system of stimuli and responses in bacterial cells governed by their population density, through which they regulate genes that control virulence factors and biofilm formation. Despite considerable research on QS and the discovery of new antibiotics, QS-controlled biofilm formation by microorganisms in clinical settings has remained a problem because of nascent drug resistance, which requires screening of diverse compounds for anti-QS activities. Cinnamon is a dietary...

  13. Pseudomonas aeruginosa in Swimming Pool Water: Evidences and Perspectives for a New Control Strategy

    Directory of Open Access Journals (Sweden)

    Marco Guida

    2016-09-01

    Full Text Available Pseudomonas aeruginosa is frequently isolated in swimming pool settings. Nine recreational and rehabilitative swimming pools were monitored according to the local legislation. The presence of P. aeruginosa was correlated to chlorine concentration. The ability of the isolates to form a biofilm on plastic materials was also investigated. In 59.5% of the samples, microbial contamination exceeded the threshold values. P. aeruginosa was isolated in 50.8% of these samples. The presence of P. aeruginosa was not correlated with free or total chlorine amount (R2 < 0.1. All the isolates were moderate- to strong-forming biofilm (Optical Density O.D.570 range 0.7–1.2. To control biofilm formation and P. aeruginosa colonization, Quantum FreeBioEnergy© (QFBE, FreeBioEnergy, Brisighella, Italy, has been applied with encouraging preliminary results. It is a new, promising control strategy based on the change of an electromagnetic field which is responsible for the proliferation of some microorganisms involved in biofilm formation, such as P. aeruginosa.

  14. Pseudomonas aeruginosa in Swimming Pool Water: Evidences and Perspectives for a New Control Strategy.

    Science.gov (United States)

    Guida, Marco; Di Onofrio, Valeria; Gallè, Francesca; Gesuele, Renato; Valeriani, Federica; Liguori, Renato; Romano Spica, Vincenzo; Liguori, Giorgio

    2016-01-01

    Pseudomonas aeruginosa is frequently isolated in swimming pool settings. Nine recreational and rehabilitative swimming pools were monitored according to the local legislation. The presence of P. aeruginosa was correlated to chlorine concentration. The ability of the isolates to form a biofilm on plastic materials was also investigated. In 59.5% of the samples, microbial contamination exceeded the threshold values. P. aeruginosa was isolated in 50.8% of these samples. The presence of P. aeruginosa was not correlated with free or total chlorine amount (R² < 0.1). All the isolates were moderate- to strong-forming biofilm (Optical Density O.D.570 range 0.7-1.2). To control biofilm formation and P. aeruginosa colonization, Quantum FreeBioEnergy© (QFBE, FreeBioEnergy, Brisighella, Italy), has been applied with encouraging preliminary results. It is a new, promising control strategy based on the change of an electromagnetic field which is responsible for the proliferation of some microorganisms involved in biofilm formation, such as P. aeruginosa. PMID:27649225

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

    DEFF Research Database (Denmark)

    Ryan, R.P.; Fouhy, Y.; Garcia, B.F.;

    2008-01-01

    Interspecies signalling through the action of diffusible signal molecules can influence the behaviour of organisms growing in polymicrobial communities. Stenotrophomonas maltophilia and Pseudomonas aeruginosa occur ubiquitously in the environment and can be found together in diverse niches...... or addition of DSF to P. aeruginosa led to increased levels of a number of proteins with roles in bacterial stress tolerance, including those implicated in resistance to cationic antimicrobial peptides. This effect was associated with increased tolerance to polymyxins. Homologues of PA1396 occur in a number...

  16. Role of biofilm in protection of the replicative form of Legionella pneumophila.

    Science.gov (United States)

    Andreozzi, Elisa; Di Cesare, Andrea; Sabatini, Luigia; Chessa, Elisa; Sisti, Davide; Rocchi, Marco; Citterio, Barbara

    2014-12-01

    The dual nature of Legionella pneumophila enables its survival in free and intracellular environments and underpins its infection and spread mechanisms. Experiments using bacterial cultures and improved RTqPCR protocols were devised to gain fresh insights into the role of biofilm in protecting the replicative form of L. pneumophila. mip gene expression was used as a marker of virulence in sessile (biofilm-bound) and planktonic (free-floating) cells of L. pneumophila serotype 1 ATCC 33152. The ratio of mip gene expression to transcriptionally active Legionella cells increased both in sessile and free-floating cells demonstrating an up-regulation of mip gene under nutrient depletion. However, a different trend was observed between the two forms, in planktonic cells the mip gene expression/transcriptionally active Legionella cells increased until the end of the experiment, while in the biofilm such increase was observed at the end of the experiment. These findings suggest a possible association between the switch to the transmissive phase of Legionella and a mip up-regulation and a role for biofilm in preserving Legionella cells in replicative form. Moreover, it has been shown that improved RTqPCR protocols are valuable tools to explore bacterial virulence. PMID:25023637

  17. Antibacterial Activity of Euphorbia hebecarpa Alcoholic Extracts Against Six Human Pathogenic Bacteria in Planktonic and Biofilm Forms

    Science.gov (United States)

    Mohsenipour, Zeinab; Hassanshahian, Mehdi

    2016-01-01

    Background Biofilm formation is a primary cause of considerable bacterial destruction. Objectives In an effort to combat these industrial and medical bacterial biofilm problems, our study aims to determine the antimicrobial effect of Euphorbia hebecarpa. Materials and Methods The inhibition efficiency of alcoholic extracts on the planktonic form of six pathogenic bacteria was evaluated using a disk diffusion technique. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values were determined by means of a macrobroth dilution method. The effects of the extracts on biofilms were calculated using a microtiter plate method. Results The results of the disk diffusion assay (MBC and MIC) confirmed that E. hebecarpa ethanolic extracts were more efficient than methanolic extracts in the inhibition of planktonic forms of bacteria. Also, the inhibitory effect of the extracts in a broth medium was greater than in a solid medium. Extracts of E. hebecarpa were found to inhibit biofilm formation better than demolish of biofilm and preventing metabolic activity of bacteria in biofilm structures. The greatest inhibitory effects of E. hebecarpa extracts were observed for the biofilm formation of B. cereus (92.81%). In addition, the greatest demolition was observed for the S. aureus biofilm (74.49%), and the metabolic activity decrement of this bacteria was highest (78.21%) of all the tested bacteria. Conclusions The results of this study suggest that E. hebecarpa extracts can be used to inhibit the planktonic and biofilm forms of these selected bacteria.

  18. Studies of protein adsorption on implant materials in relation to biofilm formation I. Activity of Pseudomonas aeruginosa on Polypropylene and High density Polyethylene in presence of serum albumin

    CERN Document Server

    Sinha, S Dutta; Maity, P K; Tarafdar, S; Moulik, S P

    2014-01-01

    The surface of biomaterials used as implants are highly susceptible to bacterial colonization and subsequent infection. The amount of protein adsorption on biomaterials, among other factors, can affect the nature and quality of biofilms formed on them. The variation in the adsorption time of the protein on the biomaterial surface produces a phenotypic change in the bacteria by alteration of the production of EPS (exoplysaccharide) matrix. Knowledge of the effects of protein adsorption on implant infection will be very useful in understanding the chemistry of the biomaterial surfaces, which can deter the formation of biofilms. It is observed that the adsorption of BSA on the biomaterial surfaces increases with time and concentration, irrespective of their type and the nature of the EPS matrix of the bacterial biofilm is dependent on the amount of protein adsorbed on the biomaterial surface. The adsorption of protein (BSA) on the biomaterials, polypropylene (PP) and high density polyethylene (HDPE) has been stu...

  19. Application of alkaliphilic biofilm-forming bacteria to improve compressive strength of cement-sand mortar.

    Science.gov (United States)

    Park, Sung-Jin; Chun, Woo-Young; Kim, Wha-Jung; Ghim, Sa-Youl

    2012-03-01

    The application of microorganisms in the field of construction material is rapidly increasing worldwide; however, almost all studies that were investigated were bacterial sources with mineral-producing activity and not with organic substances. The difference in the efficiency of using bacteria as an organic agent is that it could improve the durability of cement material. This study aimed to assess the use of biofilm-forming microorganisms as binding agents to increase the compressive strength of cement-sand material. We isolated 13 alkaliphilic biofilmforming bacteria (ABB) from a cement tetrapod block in the West Sea, Korea. Using 16S RNA sequence analysis, the ABB were partially identified as Bacillus algicola KNUC501 and Exiguobacterium marinum KNUC513. KNUC513 was selected for further study following analysis of pH and biofilm formation. Cement-sand mortar cubes containing KNUC513 exhibited greater compressive strength than mineral-forming bacteria (Sporosarcina pasteurii and Arthrobacter crystallopoietes KNUC403). To determine the biofilm effect, Dnase I was used to suppress the biofilm formation of KNUC513. Field emission scanning electron microscopy image revealed the direct involvement of organic-inorganic substance in cement-sand mortar.

  20. Bisphosphocins: novel antimicrobials for enhanced killing of drug-resistant and biofilm-forming bacteria.

    Science.gov (United States)

    Wong, Jonathan P; DiTullio, Paul; Parkinson, Steve

    2015-01-01

    The global prevalence of antibiotic resistance and the threat posed by drug-resistant superbugs are a leading challenge confronting modern medicine in the 21st century. However, the progress on the development of novel antibiotics to combat this problem is severely lagging. A more concerted effort to develop novel therapeutic agents with robust activity and unique mechanisms of action will be needed to overcome the problem of drug resistance. Furthermore, biofilm forming bacteria are known to be increasingly resistant to the actions of antibiotics and are a leading cause of mortality or morbidity in nosocomial infections. Bisphosphocins (also scientifically known as nubiotics) are novel small protonated deoxynucleotide molecules, and exert their antibacterial activity by depolarization of the bacterial cell membrane, causing bacterial cell death. Bisphosphocins may represent an effective weapon against antibiotic-resistant and biofilm-forming pathogenic bacteria. Preclinical efficacy studies in animals have shown that the compounds are safe and, efficacious against various bacterial infections, including drug-resistant pathogens. In vitro biochemical analysis confirmed that the bactericidal activity of bisphosphocins is mediated by depolarization of the bacterial cell membrane, and these compounds are better able to penetrate through bacterial biofilm and kill the biofilm encased bacteria. This article will cover the structure, mode of action, safety, efficacy and the current state of development of bisphosphocins. Together, the information presented here will present a strong case for bisphosphocins to be considered for use as new weapons to complement the existing arsenal of antimicrobial drugs and as a first line defence against drug-resistant and biofilm-forming bacteria. PMID:26597426

  1. Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA isolates of swine origin form robust biofilms.

    Directory of Open Access Journals (Sweden)

    Tracy L Nicholson

    Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA colonization of livestock animals is common and prevalence rates for pigs have been reported to be as high as 49%. Mechanisms contributing to the persistent carriage and high prevalence rates of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA strains in swine herds and production facilities have not been investigated. One explanation for the high prevalence of MRSA in swine herds is the ability of these organisms to exist as biofilms. In this report, the ability of swine LA-MRSA strains, including ST398, ST9, and ST5, to form biofilms was quantified and compared to several swine and human isolates. The contribution of known biofilm matrix components, polysaccharides, proteins and extracellular DNA (eDNA, was tested in all strains as well. All MRSA swine isolates formed robust biofilms similar to human clinical isolates. The addition of Dispersin B had no inhibitory effect on swine MRSA isolates when added at the initiation of biofilm growth or after pre-established mature biofilms formed. In contrast, the addition of proteinase K inhibited biofilm formation in all strains when added at the initiation of biofilm growth and was able to disperse pre-established mature biofilms. Of the LA-MRSA strains tested, we found ST398 strains to be the most sensitive to both inhibition of biofilm formation and dispersal of pre-formed biofilms by DNaseI. Collectively, these findings provide a critical first step in designing strategies to control or eliminate MRSA in swine herds.

  2. Laboratory investigation of the microbiologically influenced corrosion (MIC) resistance of a novel Cu-bearing 2205 duplex stainless steel in the presence of an aerobic marine Pseudomonas aeruginosa biofilm.

    Science.gov (United States)

    Xia, Jin; Yang, Chunguang; Xu, Dake; Sun, Da; Nan, Li; Sun, Ziqing; Li, Qi; Gu, Tingyue; Yang, Ke

    2015-01-01

    The microbiologically influenced corrosion (MIC) resistance of a novel Cu-bearing 2205 duplex stainless steel (2205 Cu-DSS) against an aerobic marine Pseudomonas aeruginosa biofilm was investigated. The electrochemical test results showed that Rp increased and icorr decreased sharply after long-term immersion in the inoculation medium, suggesting that 2205 Cu-DSS possessed excellent MIC resistance to the P. aeruginosa biofilm. Fluorescence microscope images showed that 2205 Cu-DSS possessed a strong antibacterial ability, and its antibacterial efficiency after one and seven days was 7.75% and 96.92%, respectively. The pit morphology comparison after 14 days between 2205 DSS and 2205 Cu-DSS demonstrated that the latter showed a considerably reduced maximum MIC pit depth compared with the former (1.44 μm vs 9.50 μm). The experimental results suggest that inhibition of the biofilm was caused by the copper ions released from the 2205 Cu-DSS, leading to its effective mitigation of MIC by P. aeruginosa. PMID:26194639

  3. Growth and virulence properties of biofilm-forming Salmonella enterica serovar typhimurium under different acidic conditions.

    Science.gov (United States)

    Xu, Hua; Lee, Hyeon-Yong; Ahn, Juhee

    2010-12-01

    This study was designed to characterize the viability and potential virulence of bofilm-forming Salmonella enterica serovar Typhimurium under different pH levels, ranging from 5 to 7. The plate count method and real-time reverse transcription-PCR (RT-PCR) were used to evaluate the survival of S. Typhimurium grown in Trypticase soy broth (TSB) adjusted to pH 5, 6, and 7 (TSB-5, TSB-6, and TSB-7, respectively) at 37°C for 10 days. In TSB-5 and TSB-6, the numbers of viable cells estimated by using the real-time RT-PCR were greater than the culturable counts enumerated by the plate count method. Reflectance micro-Fourier transform infrared (micro-FTIR) spectroscopy was used to evaluate the biochemical changes in biofilm cells. Considerable changes in chemical components were observed in the biofilm cells grown in TSB-5 and TSB-6 when compared to the cells grown in TSB-7. The enterotoxin production and invasive ability of planktonic and biofilm S. Typhimurium cells were inferred by the relative levels of expression of stn and invA. The levels of expression of stn and invA were significantly increased in biofilm S. Typhimurium cells grown in TSB-5 (1.9-fold and 3.2-fold) and TSB-6 (2.1-fold and 22.3-fold) after 10 days of incubation. These results suggest that the biofilm-forming S. Typhimurium under different pH levels might change the virulence production and stress response mechanisms.

  4. [Investigation of the correlation between biofilm forming ability of urinary Candida isolates with the use of urinary catheters and change of antifungal susceptibility in the presence of biofilm].

    Science.gov (United States)

    Aslan, Hacer; Gülmez, Dolunay

    2016-04-01

    Frequency of Candida species causing urinary tract infections is increasing, and this increase is outstanding in nosocomial urinary tract infections especially in intensive care units. The ability of biofilm formation that is contributed to the virulence of the yeast, plays a role in the pathogenesis of biomaterial-related infections and also constitutes a risk for treatment failure. The aims of this study were to compare biofilm forming abilities of Candida strains isolated from urine cultures of patients with and without urinary catheters, and to investigate the change of antifungal susceptibility in the presence of biofilm. A total of 50 Candida strains isolated from urine cultures of 25 patients with urinary catheters (10 C.tropicalis, 6 C.glabrata, 4 C.albicans, 4 C.parapsilosis, 1 C.krusei) and 25 without urinary catheters (8 C.tropicalis, 6 C.albicans, 4 C.krusei, 3 C.parapsilosis, 2 C.kefyr, 1 C.glabrata, 1 C.lusitaniae) were included in the study. Biofilm forming ability was tested by Congo red agar (CRA) and microplate XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction methods. Fluconazole (FLU) and amphotericin B (AMP-B) susceptibilities of the isolates were determined by reference microdilution method recommended by Clinical and Laboratory Standards Institute for planktonic cells and by XTT reduction assay in case of biofilm presence. Biofilm formation was detected in 12 (24%) by CRA and 50 (100%) of the isolates by XTT reduction method. None of the C.albicans (n= 10) and C.tropicalis (n= 18) strains were detected as biofilm positive by CRA, however, these strains were strongly positive by XTT reduction method. No statistically significant correlation was detected between the presence of urinary catheter and biofilm forming ability of the isolate (p> 0.05). This might be caused by the advantage of biofilm forming strains in adhesion to bladder mucosa at the initial stages of infection. For all of the isolates in

  5. [Investigation of the correlation between biofilm forming ability of urinary Candida isolates with the use of urinary catheters and change of antifungal susceptibility in the presence of biofilm].

    Science.gov (United States)

    Aslan, Hacer; Gülmez, Dolunay

    2016-04-01

    Frequency of Candida species causing urinary tract infections is increasing, and this increase is outstanding in nosocomial urinary tract infections especially in intensive care units. The ability of biofilm formation that is contributed to the virulence of the yeast, plays a role in the pathogenesis of biomaterial-related infections and also constitutes a risk for treatment failure. The aims of this study were to compare biofilm forming abilities of Candida strains isolated from urine cultures of patients with and without urinary catheters, and to investigate the change of antifungal susceptibility in the presence of biofilm. A total of 50 Candida strains isolated from urine cultures of 25 patients with urinary catheters (10 C.tropicalis, 6 C.glabrata, 4 C.albicans, 4 C.parapsilosis, 1 C.krusei) and 25 without urinary catheters (8 C.tropicalis, 6 C.albicans, 4 C.krusei, 3 C.parapsilosis, 2 C.kefyr, 1 C.glabrata, 1 C.lusitaniae) were included in the study. Biofilm forming ability was tested by Congo red agar (CRA) and microplate XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction methods. Fluconazole (FLU) and amphotericin B (AMP-B) susceptibilities of the isolates were determined by reference microdilution method recommended by Clinical and Laboratory Standards Institute for planktonic cells and by XTT reduction assay in case of biofilm presence. Biofilm formation was detected in 12 (24%) by CRA and 50 (100%) of the isolates by XTT reduction method. None of the C.albicans (n= 10) and C.tropicalis (n= 18) strains were detected as biofilm positive by CRA, however, these strains were strongly positive by XTT reduction method. No statistically significant correlation was detected between the presence of urinary catheter and biofilm forming ability of the isolate (p> 0.05). This might be caused by the advantage of biofilm forming strains in adhesion to bladder mucosa at the initial stages of infection. For all of the isolates in

  6. Pore-forming pyocin S5 utilizes the FptA ferripyochelin receptor to kill Pseudomonas aeruginosa.

    Science.gov (United States)

    Elfarash, Ameer; Dingemans, Jozef; Ye, Lumeng; Hassan, Ahmed Amir; Craggs, Michael; Reimmann, Cornelia; Thomas, Mark S; Cornelis, Pierre

    2014-02-01

    Pyocins are toxic proteins produced by some strains of Pseudomonas aeruginosa that are lethal for related strains of the same species. Some soluble pyocins (S2, S3 and S4) were previously shown to use the pyoverdine siderophore receptors to enter the cell. The P. aeruginosa PAO1 pore-forming pyocin S5 encoding gene (PAO985) was cloned into the expression vector pET15b, and the affinity-purified protein product tested for its killing activity against different P. aeruginosa strains. The results, however, did not show any correlation with a specific ferripyoverdine receptor. To further identify the S5 receptor, transposon mutants were generated. Pooled mutants were exposed to pyocin S5 and the resistant colonies growing in the killing zone were selected. The majority of S5-resistant mutants had an insertion in the fptA gene encoding the receptor for the siderophore pyochelin. Complementation of an fptA transposon mutant with the P. aeruginosa fptA gene in trans restored the sensitivity to S5. In order to define the receptor-binding domain of pyocin S5, two hybrid pyocins were constructed containing different regions from pyocin S5 fused to the C-terminal translocation and DNase killing domains of pyocin S2. Only the protein containing amino acid residues 151 to 300 from S5 showed toxicity, indicating that the pyocin S5 receptor-binding domain is not at the N-terminus of the protein as in other S-type pyocins. Pyocin S5 was, however, unable to kill Burkholderia cenocepacia strains producing a ferripyochelin FptA receptor, nor was the B. cenocepacia fptA gene able to restore the sensitivity of the resistant fptA mutant P. aeruginosa strain.

  7. Efficiency of different sanitation methods on Listeria monocytogenes biofilms formed under various environmental conditions.

    Science.gov (United States)

    Belessi, Charalambia-Eirini A; Gounadaki, Antonia S; Psomas, Antonios N; Skandamis, Panagiotis N

    2011-03-01

    The resistance of Listeria monocytogenes biofilms formed under food processing conditions, against various sanitizing agents and disinfection procedures was evaluated in the present study. The first sanitation procedure included biofilm formation on stainless steel coupons (SS) placed in tryptic soy broth supplemented with 0.6% yeast extract (TSBYE) of various concentrations of NaCl (0.5, 7.5 and 9.5%) at different temperatures (5 and 20 °C). The biofilms formed were exposed to warm (60 °C) water for 20 min, or to peroxyacetic acid (2% PAA) for 1, 2, 3 and 6 min. Treatment with warm water caused no significant (P ≥ 0.05) reductions in the attached populations. Conversely, surviving bacteria on SS coupons decreased as the exposure time to 2% PAA increased and could not be detected by culture after 6 min of exposure. Biofilms formed at 20°C were more resistant to PAA than biofilms formed at 5 °C. Salt concentration in the growth medium had no marked impact on the resistance to PAA. The second sanitation procedure included biofilm formation of nonadapted (NA) and acid-adapted (AA) cells in TSBYE of pH 5.0 and 7.0 (i.e., NA-5.0, NA-7.0 and AA-5.0, AA-7.0) at 4 °C. Coupons bearing attached cells of L. monocytogenes were periodically exposed to chlorine (0.465% Cl(-)), quaternary ammonium compound (1% QAC) and 2% PAA. The resistance of attached cells to QAC, PAA and Cl(-) followed the order: AA-5.0>NA-7.0 ≥ AA-7.0>NA-5.0. The most effective sanitizer was QAC followed by PAA and Cl(-). The results can lead to the development of efficient sanitation strategies in order to eliminate L. monocytogenes from the processing environment. Furthermore, such results may explain the presence of L. monocytogenes after sanitation as a result of cell attachment history. PMID:21093085

  8. The inhibitory effect of Thymus vulgaris extracts on the planktonic form and biofilm structures of six human pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Zinab Mohsenipour

    2015-06-01

    Full Text Available Objective: Microorganisms are responsible for many problems in industry and medicine because of biofilm formation. Therefore, this study was aimed to examine the effect of Thymus vulgaris (T. vulgaris extracts on the planktonic form and biofilm structures of six pathogenic bacteria. Materials and methods: Antimicrobial activities of the plant extracts against the planktonic form of the bacteria were determined using the disc diffusion method. MIC and MBC values were evaluated using macrobroth dilution technique. Anti-biofilm effects were assessed by microtiter plate method. Results: According to disc diffusion test (MIC and MBC, the ability of Thymus vulgaris (T. vulgaris extracts for inhibition of bacteria in planktonic form was confirmed. In dealing with biofilm structures, the inhibitory effect of the extracts was directly correlated to their concentration. Except for the inhibition of biofilm formation, efficacy of each extract was independent from type of solvent. Conclusion: According to the potential of Thymus vulgaris (T. vulgaris extracts to inhibit the test bacteria in planktonic and biofilm form, it can be suggested that Thymus vulgaris(T. vulgaris extracts can be applied as antimicrobial agents against the pathogenic bacteria particularly in biofilm forms.

  9. The inhibitory effect of Thymus vulgaris extracts on the planktonic form and biofilm structures of six human pathogenic bacteria

    Science.gov (United States)

    Mohsenipour, Zeinab; Hassanshahian, Mehdi

    2015-01-01

    Objective: Microorganisms are responsible for many problems in industry and medicine because of biofilm formation. Therefore, this study was aimed to examine the effect of Thymus vulgaris (T. vulgaris) extracts on the planktonic form and biofilm structures of six pathogenic bacteria. Materials and methods: Antimicrobial activities of the plant extracts against the planktonic form of the bacteria were determined using the disc diffusion method. MIC and MBC values were evaluated using macrobroth dilution technique. Anti-biofilm effects were assessed by microtiter plate method. Results: According to disc diffusion test (MIC and MBC), the ability of Thymus vulgaris (T. vulgaris ) extracts for inhibition of bacteria in planktonic form was confirmed. In dealing with biofilm structures, the inhibitory effect of the extracts was directly correlated to their concentration. Except for the inhibition of biofilm formation, efficacy of each extract was independent from type of solvent. Conclusion: According to the potential of Thymus vulgaris (T. vulgaris) extracts to inhibit the test bacteria in planktonic and biofilm form, it can be suggested that Thymus vulgaris (T. vulgaris) extracts can be applied as antimicrobial agents against the pathogenic bacteria particularly in biofilm forms. PMID:26442753

  10. Application of bacteriophages to reduce biofilms formed by hydrogen sulfide producing bacteria on surfaces in a rendering plant.

    Science.gov (United States)

    Gong, Chao; Jiang, Xiuping

    2015-08-01

    Hydrogen sulfide producing bacteria (SPB) in raw animal by-products are likely to grow and form biofilms in the rendering processing environments, resulting in the release of harmful hydrogen sulfide (H2S) gas. The objective of this study was to reduce SPB biofilms formed on different surfaces typically found in rendering plants by applying a bacteriophage cocktail. Using a 96-well microplate method, we determined that 3 SPB strains of Citrobacter freundii and Hafnia alvei are strong biofilm formers. Application of 9 bacteriophages (10(7) PFU/mL) from families of Siphoviridae and Myoviridae resulted in a 33%-70% reduction of biofilm formation by each SPB strain. On stainless steel and plastic templates, phage treatment (10(8) PFU/mL) reduced the attached cells of a mixed SPB culture (no biofilm) by 2.3 and 2.7 log CFU/cm(2) within 6 h at 30 °C, respectively, as compared with 2 and 1.5 log CFU/cm(2) reductions of SPB biofilms within 6 h at 30 °C. Phage treatment was also applied to indigenous SPB biofilms formed on the environmental surface, stainless steel, high-density polyethylene plastic, and rubber templates in a rendering plant. With phage treatment (10(9) PFU/mL), SPB biofilms were reduced by 0.7-1.4, 0.3-0.6, and 0.2-0.6 log CFU/cm(2) in spring, summer, and fall trials, respectively. Our study demonstrated that bacteriophages could effectively reduce the selected SPB strains either attached to or in formed biofilms on various surfaces and could to some extent reduce the indigenous SPB biofilms on the surfaces in the rendering environment.

  11. Effects of environmental parameters on the dual-species biofilms formed by Escherichia coli O157:H7 and Ralstonia insidiosa, a strong biofilm producer isolated from a fresh-cut processing plant

    Science.gov (United States)

    Biofilm forming bacteria resident to food processing facilities are a food safety concern due to the potential of biofilms to harbor foodborne bacterial pathogens. When cultured together, Ralstonia insidiosa, a strong biofilm former frequently isolated from produce processing environments, has been ...

  12. Antibiofilm and Anti-Infection of a Marine Bacterial Exopolysaccharide Against Pseudomonas aeruginosa

    OpenAIRE

    Wu, Shimei; Liu, Ge; Jin, Weihua; Xiu, Pengyuan; Sun, Chaomin

    2016-01-01

    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 P. stutzeri 273. The exopolysaccharide EPS273 not only effectively inhibits biofilm formation but also disperses preformed b...

  13. Genotypic and phenotypic analysis of S. mutans isolated from dental biofilms formed in vivo under high cariogenic conditions.

    Science.gov (United States)

    Arthur, Rodrigo Alex; Cury, Altair Antoninha Del Bel; Graner, Renata Oliveira Mattos; Rosalen, Pedro Luiz; Vale, Gláuber Campos; Paes Leme, Adriana Franco; Cury, Jaime Aparecido; Tabchoury, Cínthia Pereira Machado

    2011-01-01

    The oral cavity harbors several Streptococcus mutans genotypes, which could present distinct virulence properties. However, little is known about the diversity and virulence traits of S. mutans genotypes isolated in vivo under controlled conditions of high cariogenic challenge. This study evaluated the genotypic diversity of S. mutans isolated from dental biofilms formed in vivo under sucrose exposure, as well as their acidogenicity and aciduricity. To form biofilms, subjects rinsed their mouths with distilled water or sucrose solution 8 times/day for 3 days. S. mutans collected from saliva and biofilms were genotyped by arbitrarily-primed PCR. Genotypes identified in the biofilms were evaluated regarding their ability to lower the suspension pH through glycolysis and their acid susceptibility and F-ATPase activity. Most subjects harbored only one genotype in saliva, which was detected in almost all biofilm samples at high proportions. Genotypes isolated only in the presence of sucrose had higher acidogenicity than those isolated only in the presence of water. Genotypes from biofilms formed with sucrose were more aciduric after 30 and 60 min of incubation at pH 2.8 and 5.0, respectively. The present results suggest that biofilms formed under high cariogenic conditions may harbor more aciduric and acidogenic S. mutans genotypes.

  14. Comparative pyrosequencing analysis of bacterial community change in biofilm formed on seawater reverse osmosis membrane.

    Science.gov (United States)

    Kim, In S; Lee, Jinwook; Kima, Sung-Jo; Yu, Hye-Weon; Jang, Am

    2014-01-01

    The change in bacterial community structure induced by bacterial competition and succession was investigated during seawater reverse osmosis (SWRO) in order to elucidate a possible link between the bacterial consortium on SWRO membranes and biofouling. To date, there has been no definitive characterization of the microbial diversity in SWRO in terms of distinguishing time-dependent changes in the richness or abundance of bacterial species. For bacterial succession within biofilms on the membrane surface, SWRO using a cross-flow filtration membrane test unit was operated for 5 and 100h, respectively. As results of the pyrosequencing analysis, bacterial communities differed considerably among seawater and the 5 and 100 h samples. From a total of 33,876 pyrosequences (using a 95% sequence similarity), there were less than 1% of shared species, confirming the influence of the operational time factor and lack of similarity of these communities. During SWRO operation, the abundance of Pseudomonas stutzeri BBSPN3 (GU594474) belonging to gamma-Proteobacteria suggest that biofouling of SWRO membrane might be driven by the dominant influence of a specific species. In addition, among the bacterial competition of five bacterial species (Pseudomonas aeruginosa, Bacillus sp., Rhodobacter sp., Flavobacterium sp., and Mycobacterium sp.) competing for bacterial colonization on the SWRO membrane surfaces, it was exhibited that Bacillus sp. was the most dominant. The dominant influences ofPseudomonas sp. and Bacillus sp. on biofouling during actual SWRO is decisive depending on higher removal efficiency of the seawater pretreatment. PMID:24600849

  15. Comparative pyrosequencing analysis of bacterial community change in biofilm formed on seawater reverse osmosis membrane.

    Science.gov (United States)

    Kim, In S; Lee, Jinwook; Kima, Sung-Jo; Yu, Hye-Weon; Jang, Am

    2014-01-01

    The change in bacterial community structure induced by bacterial competition and succession was investigated during seawater reverse osmosis (SWRO) in order to elucidate a possible link between the bacterial consortium on SWRO membranes and biofouling. To date, there has been no definitive characterization of the microbial diversity in SWRO in terms of distinguishing time-dependent changes in the richness or abundance of bacterial species. For bacterial succession within biofilms on the membrane surface, SWRO using a cross-flow filtration membrane test unit was operated for 5 and 100h, respectively. As results of the pyrosequencing analysis, bacterial communities differed considerably among seawater and the 5 and 100 h samples. From a total of 33,876 pyrosequences (using a 95% sequence similarity), there were less than 1% of shared species, confirming the influence of the operational time factor and lack of similarity of these communities. During SWRO operation, the abundance of Pseudomonas stutzeri BBSPN3 (GU594474) belonging to gamma-Proteobacteria suggest that biofouling of SWRO membrane might be driven by the dominant influence of a specific species. In addition, among the bacterial competition of five bacterial species (Pseudomonas aeruginosa, Bacillus sp., Rhodobacter sp., Flavobacterium sp., and Mycobacterium sp.) competing for bacterial colonization on the SWRO membrane surfaces, it was exhibited that Bacillus sp. was the most dominant. The dominant influences ofPseudomonas sp. and Bacillus sp. on biofouling during actual SWRO is decisive depending on higher removal efficiency of the seawater pretreatment.

  16. Studies of protein adsorption on implant materials in relation to biofilm formation I. Activity of Pseudomonas aeruginosa on Polypropylene and High density Polyethylene in presence of serum albumin

    OpenAIRE

    Sinha, S Dutta; Chatterjee, Susmita; Maity, P. K.; Tarafdar, S; Moulik, S. P.

    2014-01-01

    The surface of biomaterials used as implants are highly susceptible to bacterial colonization and subsequent infection. The amount of protein adsorption on biomaterials, among other factors, can affect the nature and quality of biofilms formed on them. The variation in the adsorption time of the protein on the biomaterial surface produces a phenotypic change in the bacteria by alteration of the production of EPS (exoplysaccharide) matrix. Knowledge of the effects of protein adsorption on impl...

  17. Development and maturation of Escherichia coli K-12 biofilms

    DEFF Research Database (Denmark)

    Reisner, A.; Haagensen, J.A.J.; Schembri, Mark;

    2003-01-01

    The development and maturation of E. coli biofilms in flow-chambers was investigated. We found that the presence of transfer constitutive IncF plasmids induced biofilm development forming structures resembling those reported for Pseudomonas aeruginosa . The development occurred in a step-wise pro......The development and maturation of E. coli biofilms in flow-chambers was investigated. We found that the presence of transfer constitutive IncF plasmids induced biofilm development forming structures resembling those reported for Pseudomonas aeruginosa . The development occurred in a step....... We further provide evidence that flagella, type 1 fimbriae, curli and Ag43 are all dispensable for the observed biofilm maturation. In addition, our results indicate that cell-to-cell signalling mediated by autoinducer 2 (AI-2) is not required for differentiation of E. coli within a biofilm community....... We suggest on the basis of these results that E. coli K-12 biofilm development and maturation is dependent on cell-cell adhesion factors, which may act as inducers of self-assembly processes that result in differently structured biofilms depending on the adhesive properties on the cell surface....

  18. The inhibitory effect of Thymus vulgaris extracts on the planktonic form and biofilm structures of six human pathogenic bacteria

    OpenAIRE

    Zinab Mohsenipour; Mehdi Hassanshahian

    2015-01-01

    Objective: Microorganisms are responsible for many problems in industry and medicine because of biofilm formation. Therefore, this study was aimed to examine the effect of Thymus vulgaris (T. vulgaris) extracts on the planktonic form and biofilm structures of six pathogenic bacteria. Materials and methods: Antimicrobial activities of the plant extracts against the planktonic form of the bacteria were determined using the disc diffusion method. MIC and MBC values were evaluated using macrobrot...

  19. Antimicrobial flavonoids isolated from Indian medicinal plant Scutellaria oblonga inhibit biofilms formed by common food pathogens.

    Science.gov (United States)

    Rajendran, Narendran; Subramaniam, Shankar; Christena, Lowrence Rene; Muthuraman, Meenakshi Sundaram; Subramanian, Nagarajan Sai; Pemiah, Brindha; Sivasubramanian, Aravind

    2016-09-01

    Scutellaria oblonga Benth., a hitherto phytochemically unexplored Indian medicinal folklore plant was extracted with acetone and subjected to chromatography to yield nine flavonoids, for the first time from this plant. Antimicrobial assays were performed against 11 foodborne pathogens, and three molecules (Techtochrysin, Negletein and Quercitin-3-glucoside) depicted significant activity. These molecules were assessed for their rate of antibacterial action using time-kill curves which depicted complete inhibition of most of the bacteria within 12-16 h. The significant biofilm-reducing capability exhibited by these three molecules formed a significant finding of the current study. In most of the experiments, a 90-95% reduction in biofilms was observed. Thus, flavonoids as natural molecules from S. oblonga could be further researched to be used as potent antimicrobial and antibiofilm agents. PMID:26508034

  20. Enhanced protease production in a polymethylmethacrylate conico-cylindrical flask by two biofilm-forming bacteria.

    Science.gov (United States)

    Sarkar, Sreyashi; Roy, Debashis; Mukherjee, Joydeep

    2011-01-01

    A polymethylmethacrylate (PMMA) conico-cylindrical flask (CCF) with an inner arrangement consisting of eight equidistantly spaced rectangular strips mounted radially on a circular disk to provide additional surface area for microbial attachment was employed for protease production by two biofilm-forming bacteria, an intertidal gamma-Proteobacterium (DGII) and a chicken meat isolate, Virgibacillus pantothenticus. The flask design allowed comparison of protease production during cultivation with a hydrophilic (glass) or hydrophobic (PMMA) surface. Compared to the Erlenmeyer flask, the CCF allowed protease production that was 30% and 35% higher and growth that was 20% and 345% higher for DGII and V. pantothenticus, respectively. Protease production increased by 202% and 22% and growth by 19,275% and 940% for DGII and V. pantothenticus, respectively, in the presence of a hydrophobic as compared to a hydrophilic surface. This investigation pioneers the application of a vessel beyond the traditional shake-flask for enhancing protease production by biofilm-formers. PMID:20947343

  1. Experimental study on effect of mesna on Pseudomonas aeruginosa biofilm%巯乙磺酸钠对铜绿假单胞菌生物被膜作用的实验研究

    Institute of Scientific and Technical Information of China (English)

    陈盛; 余加林; 罗则佳; 何念海; 孙凤军

    2013-01-01

    OBJECTIVE To investigate the effect of mesna on the formation of Pseudomonas aeruginosa biofilm, and study the effect of mesna on P. aeruginosa biofilm. METHODS The broth microdilution method was performed to determine the minimal inhibitory concentration of mesna to PAO1, then a biofilm model of Pseudo-monas aeruginosa in vitro was established , the appearance of biofilm was detected by scanning electron microscope (SEM ) to assess the effect of mesna on the formation of P. aeruginosa biofilm; the bacteria colony counts in biofilm was measured by agar plate after the biofilm was treated by mesna, biofilm structure was observed under confocal laser scanning microscope (CLSM), and the parameters of biofilm structure were analyzed through pictures from CLSM with image structure analyzer (ISA) software. RESULTS The MIC value against PAO1 was 10mg/mL for mesna. In the process of Pseudomonas aeruginosa biofilm formation, scanning electron microscope showed that the mucoid materials among bacteria was significantly reduced and the thickness of biofilm was decreased in mesna group. In comparison with normal saline group, viable counts in biofilms in the mesna treatment group were less than those in the saline group, and the high-dose group (4. 06 ± 0. 12) had less positive effect than did the low-dose group(5. 84 ± 0. 24)(P<0. 05). Confocal laser scanning microscope showed that the biofilm was thinner and more scattered than the saline control group. The results of ISA showed that with the treatment of mesna, biofilm was decreased in thickness, average diffusion distance (ADD) and textual entropy (TE) in comparison with the saline control group(P<0. 05),however areal porosity(AP) was increased (P< 0. 05) , and the high-doses group was more significant than the low-doses group (P<0. 05). CONCLUSION Mesna can inhibit the formation of P. aeruginosa biofilm and disrupt the structure of P. aeruginosa biofilm.%目的 研究巯乙磺酸钠(Mesna)对铜绿假单胞菌生物被

  2. Quantitative Evaluation of Bacteria Adherent and in Biofilm on Single-Wall Carbon Nanotube-Coated Surfaces

    Directory of Open Access Journals (Sweden)

    Fabrizio Pantanella

    2011-01-01

    Full Text Available Biofilm is a common bacterial lifestyle, and it plays a crucial role in human health, causing biofilm-mediated infections. Recently, to counteract biofilm development, new nano-structured biomaterials have been proposed. However, data about the antibacterial properties of nano-structured surfaces are fragmentary and controversial, and, in particular, the susceptibility of nano-structured materials to colonization and biofilm formation by bacterial pathogens has not been yet thoroughly considered. Here, the ability of the pathogenic Streptococcus mutans and Pseudomonas aeruginosa to adhere and form biofilm on surfaces coated with single-wall carbon nanotubes (SWCNTs was analyzed. Our results showed that the surfaces of SWCNTs-coated glass beads (SWCNTs-GBs were colonized at the same extent of uncoated GBs both by S. mutans and P. aeruginosa. In conclusion, our results demonstrate that single wall SWCNTs-coated surfaces are not suitable to counteract bacterial adhesion and biofilm development.

  3. Biofilm-Forming Methicillin-Resistant Staphylococcus aureus Survive in Kupffer Cells and Exhibit High Virulence in Mice

    Directory of Open Access Journals (Sweden)

    Takuto Oyama

    2016-06-01

    Full Text Available Although Staphylococcus aureus is part of the normal body flora, heavy usage of antibiotics has resulted in the emergence of methicillin-resistant strains (MRSA. MRSA can form biofilms and cause indwelling foreign body infections, bacteremia, soft tissue infections, endocarditis, and osteomyelitis. Using an in vitro assay, we screened 173 clinical blood isolates of MRSA and selected 20 high-biofilm formers (H-BF and low-biofilm formers (L-BF. These were intravenously administered to mice and the general condition of mice, the distribution of bacteria, and biofilm in the liver, lung, spleen, and kidney were investigated. MRSA count was the highest in the liver, especially within Kupffer cells, which were positive for acid polysaccharides that are associated with intracellular biofilm. After 24 h, the general condition of the mice worsened significantly in the H-BF group. In the liver, bacterial deposition and aggregation and the biofilm-forming spot number were all significantly greater for H-BF group than for L-BF. CFU analysis revealed that bacteria in the H-BF group survived for long periods in the liver. These results indicate that the biofilm-forming ability of MRSA is a crucial factor for intracellular persistence, which could lead to chronic infections.

  4. The Activity of Cotinus coggygria Scop. Leaves on Staphylococcus aureus Strains in Planktonic and Biofilm Growth Forms

    Directory of Open Access Journals (Sweden)

    Katarína Rendeková

    2015-12-01

    Full Text Available The purpose of this study was to detect the effectiveness of Cotinus coggygria Scop. leaves methanol extract against planktonic and biofilm growth forms of Staphylococcus aureus. The antimicrobial activity was determined by the broth microdilution test. Minimal inhibitory concentrations and minimal bactericidal concentrations were detected against two collection and ten clinical S. aureus strains. Anti-biofilm activity of the tested extract was detected using 24 h bacterial biofilm on the surface of microtiter plate wells. The biofilm inhibitory activity was evaluated visually after 24 h interaction of extract with biofilm, and the eradicating activity by a regrowth method. The tested extract showed bactericidal activity against all S. aureus strains (methicillin susceptible or methicillin resistant in concentrations ranging from 0.313 to 0.625 mg·mL−1. Biofilm inhibitory concentrations were 10-times higher and biofilm eradicating concentrations 100-times higher (8 and 32 mg·mL−1, respectively. The phytochemical analysis of C. coggygria leaves 60% methanol extract performed by LC-DAD-MS/MS revealed quercetin rhamnoside, methyl gallate, and methyl trigallate as main constituents. Results of our study indicate that C. coggygria, rich in tannins and flavonoids, seems to be a prospective topical antibacterial agent with anti-biofilm activity.

  5. The Activity of Cotinus coggygria Scop. Leaves on Staphylococcus aureus Strains in Planktonic and Biofilm Growth Forms.

    Science.gov (United States)

    Rendeková, Katarína; Fialová, Silvia; Jánošová, Lucia; Mučaji, Pavel; Slobodníková, Lívia

    2015-01-01

    The purpose of this study was to detect the effectiveness of Cotinus coggygria Scop. leaves methanol extract against planktonic and biofilm growth forms of Staphylococcus aureus. The antimicrobial activity was determined by the broth microdilution test. Minimal inhibitory concentrations and minimal bactericidal concentrations were detected against two collection and ten clinical S. aureus strains. Anti-biofilm activity of the tested extract was detected using 24 h bacterial biofilm on the surface of microtiter plate wells. The biofilm inhibitory activity was evaluated visually after 24 h interaction of extract with biofilm, and the eradicating activity by a regrowth method. The tested extract showed bactericidal activity against all S. aureus strains (methicillin susceptible or methicillin resistant) in concentrations ranging from 0.313 to 0.625 mg·mL(-1). Biofilm inhibitory concentrations were 10-times higher and biofilm eradicating concentrations 100-times higher (8 and 32 mg·mL(-1), respectively). The phytochemical analysis of C. coggygria leaves 60% methanol extract performed by LC-DAD-MS/MS revealed quercetin rhamnoside, methyl gallate, and methyl trigallate as main constituents. Results of our study indicate that C. coggygria, rich in tannins and flavonoids, seems to be a prospective topical antibacterial agent with anti-biofilm activity. PMID:26729086

  6. Characterization of Newly-Formed Manganese (Hydr)oxides in Biofilms in Pinal Creek, Arizona

    Science.gov (United States)

    Gilbert, H.; Conklin, M.; O'Day, P.

    2003-12-01

    Active, biologically mediated precipitation of manganese (hydr)oxides (Mn-oxides) in Pinal Creek, Arizona, a stream with a history of high manganese levels due to historic mining practices, was studied to determine the identity of newly formed phases and their ability to sequester other metals. Packages of crushed grains of eight clean mineral substrates, quartz, ilmenite, microcline, rutile, magnetite, hematite and labradorite, were placed in Pinal Creek for one to three months. Glass slides were set out as well in order to characterize biofilm formation. After retrieval and drying, the coating distributions were characterized using scanning electron microscopy (SEM), energy dispersive analysis, and X-ray absorption spectroscopy. Morphologically, coating material developed on the different substrates after one month appeared similar to those developed after two and three months. Overall, the SEM images indicate poorly crystalline, aggregated particles that are small (less than a few microns in general) and lack geometric regularity, although size estimates are somewhat hindered by particle aggregation. The coatings that formed on the microscope slides are characterized as biofilms, as numerous microorganisms were observed using microscopy, both confocal and SEM. Samples were further characterized using extended x-ray absorption fine structure spectroscopy (EXAFS) on coatings that had been separated from mineral substrates. EXAFS spectra of material from rutile and quartz substrates and the biofilm were analyzed and fit, using a natural and synthetic birnessite compounds as reference spectra. This analysis suggests that the rutile, quartz, and biofilm samples are composed of a disordered Mn-oxide that is similar in local structure to a natural birnessite of low symmetry. The formation of disordered, poorly crystalline birnessite is important, as it is an extremely efficient metal scavenger and the interlayer vacancies in the birnessite structure aids in metal

  7. Characterizing pilus-mediated adhesion of biofilm-forming E. coli to chemically diverse surfaces using atomic force microscopy.

    Science.gov (United States)

    Xu, He; Murdaugh, Anne E; Chen, Wei; Aidala, Katherine E; Ferguson, Megan A; Spain, Eileen M; Núñez, Megan E

    2013-03-01

    Biofilms are complex communities of microorganisms living together at an interface. Because biofilms are often associated with contamination and infection, it is critical to understand how bacterial cells adhere to surfaces in the early stages of biofilm formation. Even harmless commensal Escherichia coli naturally forms biofilms in the human digestive tract by adhering to epithelial cells, a trait that presents major concerns in the case of pathogenic E. coli strains. The laboratory strain E. coli ZK1056 provides an intriguing model system for pathogenic E. coli strains because it forms biofilms robustly on a wide range of surfaces.E. coli ZK1056 cells spontaneously form living biofilms on polylysine-coated AFM cantilevers, allowing us to measure quantitatively by AFM the adhesion between native biofilm cells and substrates of our choice. We use these biofilm-covered cantilevers to probe E. coli ZK1056 adhesion to five substrates with distinct and well-characterized surface chemistries, including fluorinated, amine-terminated, and PEG-like monolayers, as well as unmodified silicon wafer and mica. Notably, after only 0-10 s of contact time, the biofilms adhere strongly to fluorinated and amine-terminated monolayers as well as to mica and weakly to "antifouling" PEG monolayers, despite the wide variation in hydrophobicity and charge of these substrates. In each case the AFM retraction curves display distinct adhesion profiles in terms of both force and distance, highlighting the cells' ability to adapt their adhesive properties to disparate surfaces. Specific inhibition of the pilus protein FimH by a nonhydrolyzable mannose analogue leads to diminished adhesion in all cases, demonstrating the critical role of type I pili in adhesion by this strain to surfaces bearing widely different functional groups. The strong and adaptable binding of FimH to diverse surfaces has unexpected implications for the design of antifouling surfaces and antiadhesion therapies. PMID

  8. Characterization of a biofilm-forming Shigella flexneri phenotype due to deficiency in Hep biosynthesis.

    Science.gov (United States)

    Xu, Dan; Zhang, Wei; Zhang, Bing; Liao, Chongbing; Shao, Yongping

    2016-01-01

    Deficiency in biosynthesis of inner core of lipopolysaccharide (LPS) rendered a characteristic biofilm-forming phenotype in E. coli. The pathological implications of this new phenotype in Shigella flexneri, a highly contagious enteric Gram-negative bacteria that is closely related to E. coli, were investigated in this study. The ΔrfaC (also referred as waaC) mutant, with incomplete inner core of LPS due to deficiency in Hep biosynthesis, was characteristic of strong biofilm formation ability and exhibited much more pronounced adhesiveness and invasiveness to human epithelial cells than the parental strain and other LPS mutants, which also showed distinct pattern of F-actin recruitment. Failure to cause keratoconjunctivitis and colonize in the intestine in guinea pigs revealed that the fitness gain on host adhesion resulted from biofilm formation is not sufficient to offset the loss of fitness on survivability caused by LPS deletion. Our study suggests a clear positive relationship between increased surface hydrophobicity and adhesiveness of Shigella flexneri, which should be put into consideration of virulence of Shigella, especially when therapeutic strategy targeting the core oligosaccharide (OS) is considered an alternative to deal with bacterial antibiotics-resistance. PMID:27478696

  9. Characterization of a biofilm-forming Shigella flexneri phenotype due to deficiency in Hep biosynthesis.

    Science.gov (United States)

    Xu, Dan; Zhang, Wei; Zhang, Bing; Liao, Chongbing; Shao, Yongping

    2016-01-01

    Deficiency in biosynthesis of inner core of lipopolysaccharide (LPS) rendered a characteristic biofilm-forming phenotype in E. coli. The pathological implications of this new phenotype in Shigella flexneri, a highly contagious enteric Gram-negative bacteria that is closely related to E. coli, were investigated in this study. The ΔrfaC (also referred as waaC) mutant, with incomplete inner core of LPS due to deficiency in Hep biosynthesis, was characteristic of strong biofilm formation ability and exhibited much more pronounced adhesiveness and invasiveness to human epithelial cells than the parental strain and other LPS mutants, which also showed distinct pattern of F-actin recruitment. Failure to cause keratoconjunctivitis and colonize in the intestine in guinea pigs revealed that the fitness gain on host adhesion resulted from biofilm formation is not sufficient to offset the loss of fitness on survivability caused by LPS deletion. Our study suggests a clear positive relationship between increased surface hydrophobicity and adhesiveness of Shigella flexneri, which should be put into consideration of virulence of Shigella, especially when therapeutic strategy targeting the core oligosaccharide (OS) is considered an alternative to deal with bacterial antibiotics-resistance.

  10. Formação de biofilme por Pseudomonas aeruginosa sobre aço inoxidável em contato com leite e seu controle por óleos essenciais

    Directory of Open Access Journals (Sweden)

    Nádia Nara BATISTA

    2014-01-01

    Full Text Available Objetivo: Avaliar a ação bacteriostática e bactericida de diferentes óleos essenciais sobre células planctônicas de Pseudomonas aeruginosa ATCC 27853, bem como verificar a ação sanitizante, dos óleos essenciais que apresentarem a menor Concentração Mínima Inibitória (CMI, sobre o biofilme formado por esta espécie, Material e Métodos: A ação bacteriostática foi realizada por meio da determinação das CMIs dos óleos de Zingiber officinale, Eugenia caryophyllus, Elettaria cardamomum, Citrus limon e Citrus reticulata v, tangerine, O tempo de morte bacteriana foi determinado utilizando-se as CMIs de cada óleo essencial submetidos a diferentes tempos de contato, O biofilme de P, aeruginosa foi desenvolvido em cupons de aço inoxidável AISI 304 dispostos em placa de Petri contendo leite tratado por Ultra Alta Temperatura (UAT, sendo incubado sob agitação de 70 rpm, a 37 °C/96 horas, Células aderidas foram removidas através de swabs e enumeradas por contagem em placas após submissão a diferentes tratamentos, Resultados: Todos os óleos essenciais apresentaram efeito bacteriostático, se destacando Z, officinale, E, caryophyllus e E, cardamomum, por apresentarem menor CMI, O tempo de morte de P, aeruginosa foi de 10 minutos quando utilizadas soluções a base de E, cardamomum e E, caryophyllus, No entanto, quando testados em biofilme, apenas E, caryophyllus eliminou as células bacterianas viáveis de P, aeruginosa, Conclusão: E, caryophyllus é uma nova alternativa para o controle do biofilme de P, aeruginosa na indústria de alimentos, pois, além de sua alta atividade antimicrobiana, é um composto natural, o que atende as exigências do mercado consumidor.

  11. Long-Term Succession of Structure and Diversity of a Biofilm Formed in a Model Drinking Water Distribution System

    OpenAIRE

    A. C. Martiny; T. M. Jorgensen; Albrechtsen, H.-J.; Arvin, E; Molin, S.

    2003-01-01

    In this study, we examined the long-term development of the overall structural morphology and community composition of a biofilm formed in a model drinking water distribution system with biofilms from 1 day to 3 years old. Visualization and subsequent quantification showed how the biofilm developed from an initial attachment of single cells through the formation of independent microcolonies reaching 30 μm in thickness to a final looser structure with an average thickness of 14.1 μm and coveri...

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

    Science.gov (United States)

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

    2015-04-01

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

  13. A simple and low-cost biofilm quantification method using LED and CMOS image sensor.

    Science.gov (United States)

    Kwak, Yeon Hwa; Lee, Junhee; Lee, Junghoon; Kwak, Soo Hwan; Oh, Sangwoo; Paek, Se-Hwan; Ha, Un-Hwan; Seo, Sungkyu

    2014-12-01

    A novel biofilm detection platform, which consists of a cost-effective red, green, and blue light-emitting diode (RGB LED) as a light source and a lens-free CMOS image sensor as a detector, is designed. This system can measure the diffraction patterns of cells from their shadow images, and gather light absorbance information according to the concentration of biofilms through a simple image processing procedure. Compared to a bulky and expensive commercial spectrophotometer, this platform can provide accurate and reproducible biofilm concentration detection and is simple, compact, and inexpensive. Biofilms originating from various bacterial strains, including Pseudomonas aeruginosa (P. aeruginosa), were tested to demonstrate the efficacy of this new biofilm detection approach. The results were compared with the results obtained from a commercial spectrophotometer. To utilize a cost-effective light source (i.e., an LED) for biofilm detection, the illumination conditions were optimized. For accurate and reproducible biofilm detection, a simple, custom-coded image processing algorithm was developed and applied to a five-megapixel CMOS image sensor, which is a cost-effective detector. The concentration of biofilms formed by P. aeruginosa was detected and quantified by varying the indole concentration, and the results were compared with the results obtained from a commercial spectrophotometer. The correlation value of the results from those two systems was 0.981 (N = 9, P CMOS image-sensor platform. PMID:25455019

  14. A simple and low-cost biofilm quantification method using LED and CMOS image sensor.

    Science.gov (United States)

    Kwak, Yeon Hwa; Lee, Junhee; Lee, Junghoon; Kwak, Soo Hwan; Oh, Sangwoo; Paek, Se-Hwan; Ha, Un-Hwan; Seo, Sungkyu

    2014-12-01

    A novel biofilm detection platform, which consists of a cost-effective red, green, and blue light-emitting diode (RGB LED) as a light source and a lens-free CMOS image sensor as a detector, is designed. This system can measure the diffraction patterns of cells from their shadow images, and gather light absorbance information according to the concentration of biofilms through a simple image processing procedure. Compared to a bulky and expensive commercial spectrophotometer, this platform can provide accurate and reproducible biofilm concentration detection and is simple, compact, and inexpensive. Biofilms originating from various bacterial strains, including Pseudomonas aeruginosa (P. aeruginosa), were tested to demonstrate the efficacy of this new biofilm detection approach. The results were compared with the results obtained from a commercial spectrophotometer. To utilize a cost-effective light source (i.e., an LED) for biofilm detection, the illumination conditions were optimized. For accurate and reproducible biofilm detection, a simple, custom-coded image processing algorithm was developed and applied to a five-megapixel CMOS image sensor, which is a cost-effective detector. The concentration of biofilms formed by P. aeruginosa was detected and quantified by varying the indole concentration, and the results were compared with the results obtained from a commercial spectrophotometer. The correlation value of the results from those two systems was 0.981 (N = 9, P < 0.01) and the coefficients of variation (CVs) were approximately threefold lower at the CMOS image-sensor platform.

  15. Retention capacity of bio-films formed on the surface of nuclear and basaltic glasses

    International Nuclear Information System (INIS)

    Available in abstract form only. Full text of publication follows: The role of the bacteria in the various compartments of a repository site was still not extensively studied. It is likely that most known bacteria cannot develop on the surface of radioactive materials but one must consider that 10% only of the bacteria species are known. As an example, a research group has recently discovered an isolated community of bacteria nearly two miles underground that derives all of its energy from the decay of radioactive rocks (LIN et al., 2006). It is generally accepted that alterations of rocks and anthropogenic products are not exclusively driven by the interaction with water or mineral aqueous solutions. Organic compounds as well as microorganisms are important in mineral degradation processes, and secondary mineralization. However, the exact role of bio-films in these processes remains unclear. The study of (AOUAD, 2006) will be presented as an example. Two materials were tested: the reference French nuclear glass SON68 17 LIDC2A2Z1 and a tholeiitic basaltic glass (natural analogue). Experiments were carried out for 19 weeks at 25 deg. C. A specific growth medium were developed which allows both the growth of Pseudomonas bacterium and a precise measurement, using ICP-MS, of trace elements solubilized from both glasses (AOUAD et al., 2005) The thickness of bio-films, analyzed by confocal laser microscopy was 40 μm for both materials. These bio-films are able to efficiently trap most of the glass constituents. They also form a protective barrier at the solid/solution interface. (authors)

  16. Diarrhea-associated biofilm formed by enteroaggregative Escherichia coli and aggregative Citrobacter freundii: a consortium mediated by putative F pili

    Directory of Open Access Journals (Sweden)

    Araújo Ana CG

    2010-02-01

    Full Text Available Abstract Background Enteroaggregative Escherichia coli (EAEC are enteropathogenic strains identified by the aggregative adhesion (AA pattern that share the capability to form biofilms. Citrobacter freundii is classically considered as an indigenous intestinal species that is sporadically associated with diarrhea. Results During an epidemiologic study focusing on infantile diarrhea, aggregative C. freundii (EACF and EAEC strains were concomitantly recovered from a severe case of mucous diarrhea. Thereby, the occurrence of synergic events involving these strains was investigated. Coinfection of HeLa cells with EACF and EAEC strains showed an 8-fold increase in the overall bacterial adhesion compared with single infections (P traA were capable of forming bacterial aggregates only in the presence of EACF. Scanning electronic microscopy analyses revealed that bacterial aggregates as well as enhanced biofilms formed by EACF and traA-positive EAEC were mediated by non-bundle forming, flexible pili. Moreover, mixed biofilms formed by EACF and traA-positive EAEC strains were significantly reduced using nonlethal concentration of zinc, a specific inhibitor of F pili. In addition, EAEC strains isolated from diarrheic children frequently produced single biofilms sensitive to zinc. Conclusions Putative F pili expressed by EAEC strains boosted mixed biofilm formation when in the presence of aggregative C. freundii.

  17. Paradoxical antifungal activity and structural observations in biofilms formed by echinocandin-resistant Candida albicans clinical isolates.

    Science.gov (United States)

    Walraven, Carla J; Bernardo, Stella M; Wiederhold, Nathan P; Lee, Samuel A

    2014-02-01

    Echinocandin-resistant clinical isolates of Candida albicans have been reported, and key-hot spot mutations in the FKS1 gene, which encodes a major glucan synthase subunit, have been identified in these (caspofungin-resistant [CAS-R]) strains. Although these mutations result in phenotypic resistance to echinocandins in planktonic cells, there is little data on antifungal susceptibilities of CAS-R C. albicans strains within biofilms. Thus, we analyzed biofilms formed by 12 C. albicans CAS-R clinical strains in which we previously identified FKS1 hot-spot mutations and compared the sessile antifungal and paradoxical activity of anidulafungin (ANID), caspofungin (CAS), and micafungin (MICA). Biofilms were formed in a 96-well static microplate model and assayed using both tetrazolium-salt reduction and crystal violet assays, as well as examination by scanning electron microscopy. We first sought to assess biofilm formation and structure in these fks1 mutants and found that the biofilm mass and metabolic activities were reduced in most of the fks1 mutants as compared with reference strain SC5314. Structural analyses revealed that the fks1 mutant biofilms were generally less dense and had a clear predominance of yeast and pseudohyphae, with unusual "pit"-like cell surface structures. We also noted that sessile minimum inhibitory concentrations (MICs) to ANID, CAS, and MICA were higher than planktonic MICs of all but one strain. The majority of strains demonstrated a paradoxical effect (PE) to particular echinocandins, in either planktonic or sessile forms. Overall, biofilms formed by echinocandin-resistant clinical isolates demonstrated varied PEs to echinocandins and were structurally characterized by a preponderance of yeast, pseudohyphae, and pit-like structures.

  18. Paradoxical antifungal activity and structural observations in biofilms formed by echinocandin-resistant Candida albicans clinical isolates.

    Science.gov (United States)

    Walraven, Carla J; Bernardo, Stella M; Wiederhold, Nathan P; Lee, Samuel A

    2014-02-01

    Echinocandin-resistant clinical isolates of Candida albicans have been reported, and key-hot spot mutations in the FKS1 gene, which encodes a major glucan synthase subunit, have been identified in these (caspofungin-resistant [CAS-R]) strains. Although these mutations result in phenotypic resistance to echinocandins in planktonic cells, there is little data on antifungal susceptibilities of CAS-R C. albicans strains within biofilms. Thus, we analyzed biofilms formed by 12 C. albicans CAS-R clinical strains in which we previously identified FKS1 hot-spot mutations and compared the sessile antifungal and paradoxical activity of anidulafungin (ANID), caspofungin (CAS), and micafungin (MICA). Biofilms were formed in a 96-well static microplate model and assayed using both tetrazolium-salt reduction and crystal violet assays, as well as examination by scanning electron microscopy. We first sought to assess biofilm formation and structure in these fks1 mutants and found that the biofilm mass and metabolic activities were reduced in most of the fks1 mutants as compared with reference strain SC5314. Structural analyses revealed that the fks1 mutant biofilms were generally less dense and had a clear predominance of yeast and pseudohyphae, with unusual "pit"-like cell surface structures. We also noted that sessile minimum inhibitory concentrations (MICs) to ANID, CAS, and MICA were higher than planktonic MICs of all but one strain. The majority of strains demonstrated a paradoxical effect (PE) to particular echinocandins, in either planktonic or sessile forms. Overall, biofilms formed by echinocandin-resistant clinical isolates demonstrated varied PEs to echinocandins and were structurally characterized by a preponderance of yeast, pseudohyphae, and pit-like structures. PMID:24576999

  19. The effect of Streptococcus mutans and Candida glabrata on Candida albicans biofilms formed on different surfaces

    NARCIS (Netherlands)

    T. Pereira-Cenci; D.M. Deng; E.A. Kraneveld; E.M.M. Manders; A.A. Del Bel Cury; J.M. ten Cate; W. Crielaard

    2008-01-01

    Although Candida containing biofilms contribute to the development of oral candidosis, the characteristics of multi-species Candida biofilms and how oral bacteria modulate these biofilms is poorly understood. The aim of this study was to investigate interactions between Candida albicans and either C

  20. Control of the Biofilms Formed by Curli- and Cellulose-Expressing Shiga Toxin-Producing Escherichia coli Using Treatments with Organic Acids and Commercial Sanitizers.

    Science.gov (United States)

    Park, Yoen Ju; Chen, Jinru

    2015-05-01

    Biofilms are a mixture of bacteria and extracellular products secreted by bacterial cells and are of great concern to the food industry because they offer physical, mechanical, and biological protection to bacterial cells. This study was conducted to quantify biofilms formed by different Shiga toxin-producing Escherichia coli (STEC) strains on polystyrene and stainless steel surfaces and to determine the effectiveness of sanitizing treatments in control of these biofilms. STEC producing various amounts of cellulose (n = 6) or curli (n = 6) were allowed to develop biofilms on polystyrene and stainless steel surfaces at 28°C for 7 days. The biofilms were treated with 2% acetic or lactic acid and manufacturer-recommended concentrations of acidic or alkaline sanitizers, and residual biofilms were quantified. Treatments with the acidic and alkaline sanitizers were more effective than those with the organic acids for removing the biofilms. Compared with their counterparts, cells expressing a greater amount of cellulose or curli formed more biofilm mass and had greater residual mass after sanitizing treatments on polystyrene than on stainless steel. Research suggests that the organic acids and sanitizers used in the present study differed in their ability to control biofilms. Bacterial surface components and cell contact surfaces can influence both biofilm formation and the efficacy of sanitizing treatments. These results provide additional information on control of biofilms formed by STEC.

  1. Controlling Biofilm Formation by Inhibiting the Quorum-Sensing Activity of Pseudomonas aeruginosa using the Ethanolic Extracts of Piper nigrum (Piperaceae Fruit, Punica granatum (Lythraceae Pericarp, and Pisum sativum (Fabaceae Seed

    Directory of Open Access Journals (Sweden)

    M.V. Dazal

    2015-07-01

    Full Text Available Bacterial biofilm formation can cause serious problems in clinical and industrial settings, which drives the development or screening of biofilm inhibitors. Pseudomonas aeruginosa is a well-known pathogen that exhibit biofilm formation through quorum-sensing, which is a bacterial cell-to-cell communication that regulates the production of many virulence factors. The inhibition of biofilm formation is a viable option for bacterial eradication. The antibacterial effect of Piper nigrum is related to the presence of phenolic and flavonoid components. Punica granatum has been reported to possess a wide range of biological actions, with tannins and alkaloids stated to be the reason of its antibacterial property. Pisum sativum, on the other hand, contains various constituents, but the tannins and phenolic compounds stated as responsible for its antibacterial property. The minimum inhibitory concentration using the susceptibility testing of P. nigrum, P. granatum, P. sativum ethanolic extracts were 6.67×10-4 g/mL, 2.1978×10-5 g/mL, and 6.25×10-4 g/mL, respectively. On the swarming assay, P. granatum and P. sativum inhibits swarming motility at concentrations of 2.1978×10-2 up to 2.1978×10-4 g/mL, and 6.25×10-2 to 6.25×10-3 g/mL, respectively. The P. nigrum extract did not inhibit the motility.

  2. Intricate interactions between the bloom-forming cyanobacterium Microcystis aeruginosa and foreign genetic elements, revealed by diversified clustered regularly interspaced short palindromic repeat (CRISPR) signatures.

    Science.gov (United States)

    Kuno, Sotaro; Yoshida, Takashi; Kaneko, Takakazu; Sako, Yoshihiko

    2012-08-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) confer sequence-dependent, adaptive resistance in prokaryotes against viruses and plasmids via incorporation of short sequences, called spacers, derived from foreign genetic elements. CRISPR loci are thus considered to provide records of past infections. To describe the host-parasite (i.e., cyanophages and plasmids) interactions involving the bloom-forming freshwater cyanobacterium Microcystis aeruginosa, we investigated CRISPR in four M. aeruginosa strains and in two previously sequenced genomes. The number of spacers in each locus was larger than the average among prokaryotes. All spacers were strain specific, except for a string of 11 spacers shared in two closely related strains, suggesting diversification of the loci. Using CRISPR repeat-based PCR, 24 CRISPR genotypes were identified in a natural cyanobacterial community. Among 995 unique spacers obtained, only 10 sequences showed similarity to M. aeruginosa phage Ma-LMM01. Of these, six spacers showed only silent or conservative nucleotide mutations compared to Ma-LMM01 sequences, suggesting a strategy by the cyanophage to avert CRISPR immunity dependent on nucleotide identity. These results imply that host-phage interactions can be divided into M. aeruginosa-cyanophage combinations rather than pandemics of population-wide infectious cyanophages. Spacer similarity also showed frequent exposure of M. aeruginosa to small cryptic plasmids that were observed only in a few strains. Thus, the diversification of CRISPR implies that M. aeruginosa has been challenged by diverse communities (almost entirely uncharacterized) of cyanophages and plasmids.

  3. Evaluation of Various Metallic Coatings on Steel to Mitigate Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Hajime Ikigai

    2009-02-01

    Full Text Available In marine environments and water systems, it is easy for many structures to form biofilms on their surfaces and to be deteriorated due to the corrosion caused by biofilm formation by bacteria. The authors have investigated the antibacterial effects of metallic elements in practical steels so far to solve food-related problems, using Escherichia coli and Staphylococcus aureus. However, from the viewpoint of material deterioration caused by bacteria and their antifouling measures, we should consider the biofilm behavior as aggregate rather than individual bacterium. Therefore, we picked up Pseudomonas aeruginosa and Pseudoalteromonas carageenovara in this study, since they easily form biofilms in estuarine and marine environments. We investigated what kind of metallic elements could inhibit the biofilm formation at first and then discussed how the thin films of those inhibitory elements on steels could affect biofilm formation. The information would lead to the establishment of effective antifouling measures against corrosion in estuarine and marine environments.

  4. Atypical Enteropathogenic Escherichia coli Strains form Biofilm on Abiotic Surfaces Regardless of Their Adherence Pattern on Cultured Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Hebert F. Culler

    2014-01-01

    Full Text Available The aim of this study was to determine the capacity of biofilm formation of atypical enteropathogenic Escherichia coli (aEPEC strains on abiotic and biotic surfaces. Ninety-one aEPEC strains, isolated from feces of children with diarrhea, were analyzed by the crystal violet (CV assay on an abiotic surface after 24 h of incubation. aEPEC strains representing each HEp-2 cell type of adherence were analyzed after 24 h and 6, 12, and 18 days of incubation at 37°C on abiotic and cell surfaces by CFU/cm2 counting and confocal laser scanning microscopy (CLSM. Biofilm formation on abiotic surfaces occurred in 55 (60.4% of the aEPEC strains. There was no significant difference in biofilm biomass formation on an abiotic versus prefixed cell surface. The biofilms could be visualized by CLSM at various developmental stages. aEPEC strains are able to form biofilm on an abiotic surface with no association with their adherence pattern on HEp-2 cells with the exception of the strains expressing UND (undetermined adherence. This study revealed the capacity of adhesion and biofilm formation by aEPEC strains on abiotic and biotic surfaces, possibly playing a role in pathogenesis, mainly in cases of persistent diarrhea.

  5. Targeted changes of the cell wall proteome influence Candida albicans ability to form single- and multi-strain biofilms.

    Directory of Open Access Journals (Sweden)

    Vitor Cabral

    2014-12-01

    Full Text Available Biofilm formation is an important virulence trait of the pathogenic yeast Candida albicans. We have combined gene overexpression, strain barcoding and microarray profiling to screen a library of 531 C. albicans conditional overexpression strains (∼10% of the genome for genes affecting biofilm development in mixed-population experiments. The overexpression of 16 genes increased strain occupancy within a multi-strain biofilm, whereas overexpression of 4 genes decreased it. The set of 16 genes was significantly enriched for those encoding predicted glycosylphosphatidylinositol (GPI-modified proteins, namely Ihd1/Pga36, Phr2, Pga15, Pga19, Pga22, Pga32, Pga37, Pga42 and Pga59; eight of which have been classified as pathogen-specific. Validation experiments using either individually- or competitively-grown overexpression strains revealed that the contribution of these genes to biofilm formation was variable and stage-specific. Deeper functional analysis of PGA59 and PGA22 at a single-cell resolution using atomic force microscopy showed that overexpression of either gene increased C. albicans ability to adhere to an abiotic substrate. However, unlike PGA59, PGA22 overexpression led to cell cluster formation that resulted in increased sensitivity to shear forces and decreased ability to form a single-strain biofilm. Within the multi-strain environment provided by the PGA22-non overexpressing cells, PGA22-overexpressing cells were protected from shear forces and fitter for biofilm development. Ultrastructural analysis, genome-wide transcript profiling and phenotypic analyses in a heterologous context suggested that PGA22 affects cell adherence through alteration of cell wall structure and/or function. Taken together, our findings reveal that several novel predicted GPI-modified proteins contribute to the cooperative behaviour between biofilm cells and are important participants during C. albicans biofilm formation. Moreover, they illustrate the power

  6. Synthesis of Bioinspired Carbohydrate Amphiphiles that Promote and Inhibit Biofilms.

    Science.gov (United States)

    Dane, Eric L; Ballok, Alicia E; O'Toole, George A; Grinstaff, Mark W

    2014-02-01

    The synthesis and characterization of a new class of bioinspired carbohydrate amphiphiles that modulate Pseudomonas aeruginosa biofilm formation are reported. The carbohydrate head is an enantiopure poly-amido-saccharide (PAS) prepared by a controlled anionic polymerization of β-lactam monomers derived from either glucose or galactose. The supramolecular assemblies formed by PAS amphiphiles are investigated in solution using fluorescence assays and dynamic light scattering. Dried samples are investigated using X-ray, infrared spectroscopy, and transmission electron microscopy. Additionally, the amphiphiles are evaluated for their ability to modulate biofilm formation by the Gram-negative bacterium Pseudomonas aeruginosa. Remarkably, from a library of eight amphiphiles, we identify a structure that promotes biofilm formation and two structures that inhibit biofilm formation. Using biological assays and electron microscopy, we relate the chemical structure of the amphiphiles to the observed activity. Materials that modulate the formation of biofilms by bacteria are important both as research tools for microbiologists to study the process of biofilm formation and for their potential to provide new drug candidates for treating biofilm-associated infections.

  7. Histamine-producing Lactobacillus parabuchneri strains isolated from grated cheese can form biofilms on stainless steel.

    Science.gov (United States)

    Diaz, Maria; Del Rio, Beatriz; Sanchez-Llana, Esther; Ladero, Victor; Redruello, Begoña; Fernández, María; Martin, M Cruz; Alvarez, Miguel A

    2016-10-01

    The consumption of food containing large amounts of histamine can lead to histamine poisoning. Cheese is one of the most frequently involved foods. Histamine, one of the biogenic amines (BAs) exhibiting the highest safety risk, accumulates in food contaminated by microorganisms with histidine decarboxylase activity. The origin of these microorganisms may be very diverse with contamination likely occurring during post-ripening processing, but the microorganisms involved during this manufacturing step have never been identified. The present work reports the isolation of 21 histamine-producing Lactobacillus parabuchneri strains from a histamine-containing grated cheese. PCR revealed that every isolate carried the histidine decarboxylase gene (hdcA). Eight lineages were identified based on the results of genome PFGE restriction analysis plus endonuclease restriction profile analysis of the carried plasmids. Members of all lineages were able to form biofilms on polystyrene and stainless steel surfaces. L. parabuchneri is therefore an undesirable species in the dairy industry; the biofilms it can produce on food processing equipment represent a reservoir of histamine-producing bacteria and thus a source of contamination of post-ripening-processed cheeses. PMID:27375247

  8. Histamine-producing Lactobacillus parabuchneri strains isolated from grated cheese can form biofilms on stainless steel.

    Science.gov (United States)

    Diaz, Maria; Del Rio, Beatriz; Sanchez-Llana, Esther; Ladero, Victor; Redruello, Begoña; Fernández, María; Martin, M Cruz; Alvarez, Miguel A

    2016-10-01

    The consumption of food containing large amounts of histamine can lead to histamine poisoning. Cheese is one of the most frequently involved foods. Histamine, one of the biogenic amines (BAs) exhibiting the highest safety risk, accumulates in food contaminated by microorganisms with histidine decarboxylase activity. The origin of these microorganisms may be very diverse with contamination likely occurring during post-ripening processing, but the microorganisms involved during this manufacturing step have never been identified. The present work reports the isolation of 21 histamine-producing Lactobacillus parabuchneri strains from a histamine-containing grated cheese. PCR revealed that every isolate carried the histidine decarboxylase gene (hdcA). Eight lineages were identified based on the results of genome PFGE restriction analysis plus endonuclease restriction profile analysis of the carried plasmids. Members of all lineages were able to form biofilms on polystyrene and stainless steel surfaces. L. parabuchneri is therefore an undesirable species in the dairy industry; the biofilms it can produce on food processing equipment represent a reservoir of histamine-producing bacteria and thus a source of contamination of post-ripening-processed cheeses.

  9. Relationship between clinical site of isolation and ability to form biofilms in vitro in nontypeable Haemophilus influenzae.

    Science.gov (United States)

    Obaid, Najla A; Jacobson, Glenn A; Tristram, Stephen

    2015-03-01

    Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen associated with a range of infections, including various lower respiratory infections, otitis media, and conjunctivitis. There is some debate as to whether or not NTHi produces biofilms and, if so, whether or not this is relevant to pathogenesis. Although many studies have examined the association between in vitro biofilm formation and isolates from a specific infection type, few have made comparisons from isolates from a broad range of isolates grouped by clinical source. In our study 50 NTHi from different clinical sources, otitis media, conjunctivitis, lower respiratory tract infections in both cystic fibrosis and non-cystic fibrosis patients, and nasopharyngeal carriage, plus 10 nasopharyngeal isolates of the commensal Haemophilus haemolyticus were tested for the ability to form biofilm by using a static microtitre plate crystal violet assay. A high degree of variation in biofilm forming ability was observed across all isolates, with no statistically significant differences observed between the groups, with the exception of the isolates from conjunctivitis. These isolates had uniformly lower biofilm forming ability compared with isolates from the other groups (p < 0.005). PMID:25706230

  10. Effects of environmental parameters on the dual-species biofilms formed by Escherichia coli O157:H7 and Ralstonia insidiosa, a strong biofilm producer isolated from a fresh-cut produce processing plant.

    Science.gov (United States)

    Liu, Nancy T; Nou, Xiangwu; Bauchan, Gary R; Murphy, Charles; Lefcourt, Alan M; Shelton, Daniel R; Lo, Y Martin

    2015-01-01

    Biofilm-forming bacteria resident to food processing facilities are a food safety concern due to the potential of biofilms to harbor foodborne bacterial pathogens. When cultured together, Ralstonia insidiosa, a strong biofilm former frequently isolated from produce processing environments, has been shown to promote the incorporation of Escherichia coli O157:H7 into dual-species biofilms. In this study, interactions between E. coli O157:H7 and R. insidiosa were examined under different incubating conditions. Under static culture conditions, the incorporation of E. coli O157:H7 into biofilms with R. insidiosa was not significantly affected by either low incubating temperature (10°C) or by limited nutrient availability. Greater enhancement of E. coli O157:H7 incorporation in dual-species biofilms was observed by using a continuous culture system with limited nutrient availability. Under the continuous culture conditions used in this study, E coli O157:H7 cells showed a strong tendency of colocalizing with R. insidiosa on a glass surface at the early stage of biofilm formation. As the biofilms matured, E coli O157:H7 cells were mostly found at the bottom layer of the dual-species biofilms, suggesting an effective protection by R. insidiosa in the mature biofilms.

  11. 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......-mucoid isolates observed in this particular P. aeruginosa clone reflects different adaptation strategies used by these two phenotypes in the different niches of the CF lung environment....

  12. Raman spectroscopic differentiation of planktonic bacteria and biofilms.

    Science.gov (United States)

    Kusić, Dragana; Kampe, Bernd; Ramoji, Anuradha; Neugebauer, Ute; Rösch, Petra; Popp, Jürgen

    2015-09-01

    Both biofilm formations as well as planktonic cells of water bacteria such as diverse species of the Legionella genus as well as Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli were examined in detail by Raman microspectroscopy. Production of various molecules involved in biofilm formation of tested species in nutrient-deficient media such as tap water was observed and was particularly evident in the biofilms formed by six Legionella species. Biofilms of selected species of the Legionella genus differ significantly from the planktonic cells of the same organisms in their lipid amount. Also, all Legionella species have formed biofilms that differ significantly from the biofilms of the other tested genera in the amount of lipids they produced. We believe that the significant increase in the synthesis of this molecular species may be associated with the ability of Legionella species to form biofilms. In addition, a combination of Raman microspectroscopy with chemometric approaches can distinguish between both planktonic form and biofilms of diverse bacteria and could be used to identify samples which were unknown to the identification model. Our results provide valuable data for the development of fast and reliable analytic methods based on Raman microspectroscopy, which can be applied to the analysis of tap water-adapted microorganisms without any cultivation step.

  13. Co-occurence of filamentation defects and impaired biofilms in Candida albicans protein kinase mutants.

    Science.gov (United States)

    Konstantinidou, Nina; Morrissey, John Patrick

    2015-12-01

    Pathogenicity of Candida albicans is linked with its developmental stages, notably the capacity switch from yeast-like to hyphal growth, and to form biofilms on surfaces. To better understand the cellular processes involved in C. albicans development, a collection of 63 C. albicans protein kinase mutants was screened for biofilm formation in a microtitre plate assay. Thirty-eight mutants displayed some degree of biofilm impairment, with 20 categorised as poor biofilm formers. All the poor biofilm formers were also defective in the switch from yeast to hyphae, establishing it as a primary defect. Five genes, VPS15, IME2, PKH3, PGA43 and CEX1, encode proteins not previously reported to influence hyphal development or biofilm formation. Network analysis established that individual components of some processes, most interestingly MAP kinase pathways, are not required for biofilm formation, most likely indicating functional redundancy. Mutants were also screened for their response to bacterial supernatants and it was found that Pseudomonas aeruginosa supernatants inhibited biofilm formation in all mutants, regardless of the presence of homoserine lactones (HSLs). In contrast, Candida morphology was only affected by supernatant containing HSLs. This confirms the distinct HSL-dependent inhibition of filamentation and the HSL-independent impairment of biofilm development by P. aeruginosa.

  14. Efficacy of dental unit waterlines disinfectants on a polymicrobial biofilm.

    Science.gov (United States)

    Costa, Damien; Girardot, Marion; Bertaux, Joanne; Verdon, Julien; Imbert, Christine

    2016-03-15

    Due to their high surface-volume ratio, their laminar flow and frequent stagnation periods, dental unit waterlines (DUWL) foster the attachment of microorganisms and the development of biofilm, resulting in the continuous contamination of the outlet water from dental units; this contamination may be responsible for a potential risk of infection due to the exposure of patients and medical staff to droplet inhalation or splashed water. In this study, the anti-biofilm activity of three disinfectants recommended by dental unit manufacturers -Calbenium(©), Oxygenal 6(©) and Sterispray(©) - was evaluated. A dynamic model simulating DUWL conditions was developed and polymicrobial biofilms containing bacteria (Pseudomonas aeruginosa), fungi (Candida albicans) and Free Living Amoeba (FLA: Vermamoeba vermiformis) were allowed to form. The ability of disinfectants to reduce biofilm formation or to eradicate an already formed biofilm was evaluated. Results showed the various effects of the tested disinfectants according to their composition, concentration and the targeted species. V. vermiformis was resistant to disinfectants, regardless of the tested concentrations and the concentrations recommended by manufacturers were not the most appropriate. Results also showed that Calbenium(©) was the most effective disinfectant to reduce already formed biofilms; its maximum efficiency was observed from 0.5% on both P. aeruginosa and C. albicans compared to 2 and 3% respectively for Sterispray(©). The maximum efficiency of Oxygenal(©) was observed from 3% on P. aeruginosa but Oxygenal(©) was unable to totally eliminate C. albicans in the tested conditions, contrary to other disinfectants. Calbenium(©) was able to prevent biofilm formation efficiently even if it displayed no prophylactic activity against V. vermiformis. Overall, the FLA survival may contribute to maintaining other species. Finally the tested disinfectants were partially active against sessile microorganisms

  15. Bactericidal Compounds Controlling Growth of the Plant Pathogen Pseudomonas syringae pv. actinidiae, Which Forms Biofilms Composed of a Novel Exopolysaccharide

    Science.gov (United States)

    Ghods, Shirin; Sims, Ian M.; Moradali, M. Fata

    2015-01-01

    Pseudomonas syringae pv. actinidiae is the major cause of bacterial canker and is a severe threat to kiwifruit production worldwide. Many aspects of the disease caused by P. syringae pv. actinidiae, such as the pathogenicity-relevant formation of a biofilm composed of extracellular polymeric substances (EPSs), are still unknown. Here, a highly virulent strain of P. syringae pv. actinidiae, NZ V-13, was studied with respect to biofilm formation and architecture using a flow cell system combined with confocal laser scanning microscopy. The biofilm formed by P. syringae pv. actinidiae NZ V-13 was heterogeneous, consisting of a thin cellular base layer 5 μm thick and microcolonies with irregular structures. The major component of the EPSs produced by P. syringae pv. actinidiae NZ V-13 bacteria was isolated and identified to be an exopolysaccharide. Extensive compositional and structural analysis showed that rhamnose, fucose, and glucose were the major constituents, present at a ratio of 5:1.5:2. Experimental evidence that P. syringae pv. actinidiae NZ V-13 produces two polysaccharides, a branched α-d-rhamnan with side chains of terminal α-d-Fucf and an α-d-1,4-linked glucan, was obtained. The susceptibility of the cells in biofilms to kasugamycin and chlorine dioxide was assessed. About 64 and 73% of P. syringae pv. actinidiae NZ V-13 cells in biofilms were killed when kasugamycin and chlorine dioxide were used at 5 and 10 ppm, respectively. Kasugamycin inhibited the attachment of P. syringae pv. actinidiae NZ V-13 to solid surfaces at concentrations of 80 and 100 ppm. Kasugamycin was bacteriostatic against P. syringae pv. actinidiae NZ V-13 growth in the planktonic mode, with the MIC being 40 to 60 ppm and a bactericidal effect being found at 100 ppm. Here we studied the formation, architecture, and composition of P. syringae pv. actinidiae biofilms as well as used the biofilm as a model to assess the efficacies of bactericidal compounds. PMID:25841017

  16. The Pseudomonas aeruginosa CreBC Two-Component System Plays a Major Role in the Response to β-Lactams, Fitness, Biofilm Growth, and Global Regulation

    OpenAIRE

    Zamorano, Laura; Moyà, Bartolomé; Juan, Carlos; Mulet, Xavier; Blázquez, Jesús; Oliver, Antonio

    2014-01-01

    Pseudomonas aeruginosa is a ubiquitous versatile environmental microorganism with a remarkable ability to grow under diverse environmental conditions. Moreover, P. aeruginosa is responsible for life-threatening infections in immunocompromised and cystic fibrosis patients, as the extraordinary capacity of this pathogen to develop antimicrobial resistance dramatically limits our therapeutic arsenal. Its large genome carries an outstanding number of genes belonging to regulatory systems, includi...

  17. A trait-based approach to bacterial biofilms in soil.

    Science.gov (United States)

    Lennon, Jay T; Lehmkuhl, Brent K

    2016-09-01

    A trait-based approach focuses on attributes of taxa that influence the structure and function of communities. Biofilm production is a common trait among microorganisms in a wide range of environmental, engineered, and host-associated ecosystems. Here, we used Pseudomonas aeruginosa to link biofilm production to moisture availability, a common stressor for microorganisms in soil. First, we demonstrate that biofilm production is a response trait that influences the desiccation phenotype by increasing survivorship, shifting the niche space, and reducing the minimum water potential needed to sustain a net-positive growth rate (Ψ*). Although the allocation of resources to biofilms is thought to be costly, we found no evidence for a trade-off between fitness and biofilm production along a soil moisture gradient. Second, we demonstrated that biofilm production is an effect trait. Specifically, biofilm production increased water retention in soils that were exposed to a series of drying and rewetting cycles. Although this form of niche construction should affect species interactions, we found no evidence that the benefits of biofilm production were extended to another co-occurring soil bacterium. Together, our results support the view that biofilm production is an important trait that may contribute to the distribution, abundance, and functioning of microorganisms in soils. PMID:27104876

  18. Characterization of structures in biofilms formed by a Pseudomonas fluorescens isolated from soil

    Directory of Open Access Journals (Sweden)

    Wu Siva

    2009-05-01

    Full Text Available Abstract Background Microbial biofilms represent an incompletely understood, but fundamental mode of bacterial growth. These sessile communities typically consist of stratified, morphologically-distinct layers of extracellular material, where numerous metabolic processes occur simultaneously in close proximity. Limited reports on environmental isolates have revealed highly ordered, three-dimensional organization of the extracellular matrix, which may hold important implications for biofilm physiology in vivo. Results A Pseudomonas spp. isolated from a natural soil environment produced flocculent, nonmucoidal biofilms in vitro with unique structural features. These mature biofilms were made up of numerous viable bacteria, even after extended culture, and contained up to 50% of proteins and accumulated 3% (by dry weight calcium, suggesting an important role for the divalent metal in biofilm formation. Ultrastructurally, the mature biofilms contained structural motifs consisting of dense, fibrillary clusters, nanofibers, and ordered, honeycomb-like chambers enveloped in thin sheets. Conclusion Mature biofilms contained living bacteria and were structurally, chemically, and physiologically heterogeneous. The principal architectural elements observed by electron microscopy may represent useful morphological clues for identifying bacterial biofilms in vivo. The complexity and reproducibility of the structural motifs observed in bacterial biofilms appear to be the result of organized assembly, suggesting that this environmental isolate may possess ecological advantages in its natural habitat.

  19. 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.

  20. Antibiofilm and Anti-Infection of a Marine Bacterial Exopolysaccharide Against Pseudomonas aeruginosa.

    Science.gov (United States)

    Wu, Shimei; Liu, Ge; Jin, Weihua; Xiu, Pengyuan; Sun, Chaomin

    2016-01-01

    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 P. stutzeri 273. The exopolysaccharide EPS273 not only effectively inhibits biofilm formation but also disperses preformed biofilm of P. 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 2 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. PMID:26903981

  1. Staphylococcus aureus Clinical Isolates: Antibiotic Susceptibility, Molecular Characteristics, and Ability to Form Biofilm

    Directory of Open Access Journals (Sweden)

    N. Indrawattana

    2013-01-01

    Full Text Available Periodic monitoring of Staphylococcus aureus characteristics in a locality is imperative as their drug-resistant variants cause treatment problem. In this study, antibiograms, prevalence of toxin genes (sea-see, seg-ser, seu, tsst-1, eta, etb, and etd, PFGE types, accessory gene regulator (agr groups, and ability to form biofilm of 92 S. aureus Thailand clinical isolates were investigated. They were classified into 10 drug groups: groups 1–7 (56 isolates were methicillin resistant (MRSA and 8–10 (36 isolates were methicillin sensitive (MSSA. One isolate did not have any toxin gene, 4 isolates carried one toxin gene (seq, and 87 isolates had two or more toxin genes. No isolate had see, etb, or tsst-1; six isolates had eta or etd. Combined seg-sei-sem-sen-seo of the highly prevalent egc locus was 26.1%. The seb, sec, sel, seu, and eta associated significantly with MSSA; sek was more in MRSA. The sek-seq association was 52.17% while combined sed-sej was not found. Twenty-three PFGE types were revealed, no association of toxin genes with PFGE types. All four agr groups were present; agr group 1 was predominant (58.70% but agr group 2 strains carried more toxin genes and were more frequent toxin producers. Biofilm formation was found in 72.83% of the isolates but there was no association with antibiograms. This study provides insight information on molecular and phenotypic markers of Thailand S. aureus clinical isolates which should be useful for future active surveillance that aimed to control a spread of existing antimicrobial resistant bacteria and early recognition of a newly emerged variant.

  2. Multi-channel microfluidic biosensor platform applied for online monitoring and screening of biofilm formation and activity.

    Science.gov (United States)

    Bruchmann, Julia; Sachsenheimer, Kai; Rapp, Bastian E; Schwartz, Thomas

    2015-01-01

    Bacterial colonization of surfaces and interfaces has a major impact on various areas including biotechnology, medicine, food industries, and water technologies. In most of these areas biofilm development has a strong impact on hygiene situations, product quality, and process efficacies. In consequence, biofilm manipulation and prevention is a fundamental issue to avoid adverse impacts. For such scenario online, non-destructive biofilm monitoring systems become important in many technical and industrial applications. This study reports such a system in form of a microfluidic sensor platform based on the combination of electrical impedance spectroscopy and amperometric current measurement, which allows sensitive online measurement of biofilm formation and activity. A total number of 12 parallel fluidic channels enable real-time online screening of various biofilms formed by different Pseudomonas aeruginosa and Stenotrophomonas maltophilia strains and complex mixed population biofilms. Experiments using disinfectant and antibiofilm reagents demonstrate that the biofilm sensor is able to discriminate between inactivation/killing of bacteria and destabilization of biofilm structures. The impedance and amperometric sensor data demonstrated the high dynamics of biofilms as a consequence of distinct responses to chemical treatment strategies. Gene expression of flagellar and fimbrial genes of biofilms grown inside the microfluidic system supported the detected biofilm growth kinetics. Thus, the presented biosensor platform is a qualified tool for assessing biofilm formation in specific environments and for evaluating the effectiveness of antibiofilm treatment strategies. PMID:25706987

  3. Multi-channel microfluidic biosensor platform applied for online monitoring and screening of biofilm formation and activity.

    Directory of Open Access Journals (Sweden)

    Julia Bruchmann

    Full Text Available Bacterial colonization of surfaces and interfaces has a major impact on various areas including biotechnology, medicine, food industries, and water technologies. In most of these areas biofilm development has a strong impact on hygiene situations, product quality, and process efficacies. In consequence, biofilm manipulation and prevention is a fundamental issue to avoid adverse impacts. For such scenario online, non-destructive biofilm monitoring systems become important in many technical and industrial applications. This study reports such a system in form of a microfluidic sensor platform based on the combination of electrical impedance spectroscopy and amperometric current measurement, which allows sensitive online measurement of biofilm formation and activity. A total number of 12 parallel fluidic channels enable real-time online screening of various biofilms formed by different Pseudomonas aeruginosa and Stenotrophomonas maltophilia strains and complex mixed population biofilms. Experiments using disinfectant and antibiofilm reagents demonstrate that the biofilm sensor is able to discriminate between inactivation/killing of bacteria and destabilization of biofilm structures. The impedance and amperometric sensor data demonstrated the high dynamics of biofilms as a consequence of distinct responses to chemical treatment strategies. Gene expression of flagellar and fimbrial genes of biofilms grown inside the microfluidic system supported the detected biofilm growth kinetics. Thus, the presented biosensor platform is a qualified tool for assessing biofilm formation in specific environments and for evaluating the effectiveness of antibiofilm treatment strategies.

  4. Bacterial biofilms. Bacteria Quorum sensing in biofilms

    OpenAIRE

    E. S. Vorobey; O. S. Voronkova; A. I. Vinnikov

    2012-01-01

    Data on biofilms, their structure and properties, peculiarities of formation and interaction between microorganisms in the film are presented. Information on discovery and study of biofilms, importance of biofilms in the medical and clinical microbiology are offered. The data allow to interpret biofilm as a form of existence of human normal microflora. For the exchange of information within the biofilm between the individual cells of the same or different species bacteria use the signal molec...

  5. Biofilm streamers cause rapid clogging of flow systems

    Science.gov (United States)

    Shen, Yi; Drescher, Knut; Wingreen, Ned; Bassler, Bonnie; Stone, Howard

    2012-11-01

    Biofilms are antibiotic-resistant, sessile bacterial communities that are found on most surfaces on Earth. In addition to constituting the most abundant form of bacterial life, biofilms also cause chronic and medical device-associated infections. Despite their importance, basic information about how biofilms behave in common ecological environments is lacking. Here we demonstrate that flow through soil-like porous materials, industrial filters, and medical stents dramatically modifies the morphology of Pseudomonas aeruginosa biofilms to form streamers which over time bridge the space between obstacles and corners in non-uniform environments. Using a microfluidic model system we find that, contrary to the accepted paradigm, the accumulation of surface-attached bacterial biofilm has little effect on flow resistance whereas the formation of biofilm streamers causes sudden and rapid clogging. The time at which clogging happens depends on bacterial growth, while the duration of the clogging transition is driven by flow-mediated transport of bacteria to the clogging site. Flow-induced shedding of extracellular matrix from the resident biofilm generates a sieve-like network that catches bacteria flowing by, which add to the network of extracellular matrix, to cause exponentially rapid clogging. We expect these biofilm streamers to be ubiquitous in nature, and to have profound effects on flow through porous materials in environmental, industrial, and medical environments.

  6. Bacteriophages as an alternative strategy for fighting biofilm development.

    Science.gov (United States)

    Parasion, Sylwia; Kwiatek, Magdalena; Gryko, Romuald; Mizak, Lidia; Malm, Anna

    2014-01-01

    The ability of microbes to form biofilms is an important element of their pathogenicity, and biofilm formation is a serious challenge for today's medicine. Fighting the clinical complications associated with biofilm formation is very difficult and linked to a high risk of failure, especially in a time of increasing bacterial resistance to antibiotics. Bacterial species most commonly isolated from biofilms include coagulase-negative staphylococci, Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter spp. The frequent failure of antibiotic therapy led researchers to look for alternative methods and experiment with the use of antibacterial factors with a mechanism of action different from that of antibiotics. Experimental studies with bacteriophages and mixtures thereof, expressing lytic properties against numerous biofilm-forming bacterial species showed that bacteriophages may both prevent biofilm formation and contribute to eradication of biofilm bacteria. A specific role is played here by phage depolymerases, which facilitate the degradation of extracellular polymeric substances (EPS) and thus the permeation of bacteriophages into deeper biofilm layers and lysis of the susceptible bacterial cells. Much hope is placed in genetic modifications of bacteriophages that would allow the equipping bacteriophages with the function of depolymerase synthesis. The use of phage cocktails prevents the development of phage-resistant bacteria.

  7. Isolation of biofilm-forming bacteria from a fresh-cut processing plant and co-culturing with E. coli O157:H7

    Science.gov (United States)

    In produce processing plants, biofilms can theoretically provide a supporting environment for pathogenic bacteria that is resistant to cleaning and sanitizing efforts. The objective of this study was to recover bacteria from a commercial produce processing plant that have the ability to form biofilm...

  8. Wild Mushroom Extracts as Inhibitors of Bacterial Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Maria José Alves

    2014-08-01

    Full Text Available Microorganisms can colonize a wide variety of medical devices, putting patients in risk for local and systemic infectious complications, including local-site infections, catheter-related bloodstream infections, and endocarditis. These microorganisms are able to grow adhered to almost every surface, forming architecturally complex communities termed biofilms. The use of natural products has been extremely successful in the discovery of new medicine, and mushrooms could be a source of natural antimicrobials. The present study reports the capacity of wild mushroom extracts to inhibit in vitro biofilm formation by multi-resistant bacteria. Four Gram-negative bacteria biofilm producers (Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, and Acinetobacter baumannii isolated from urine were used to verify the activity of Russula delica, Fistulina hepatica, Mycena rosea, Leucopaxilus giganteus, and Lepista nuda extracts. The results obtained showed that all tested mushroom extracts presented some extent of inhibition of biofilm production. Pseudomonas aeruginosa was the microorganism with the highest capacity of biofilm production, being also the most susceptible to the extracts inhibition capacity (equal or higher than 50%. Among the five tested extracts against E. coli, Leucopaxillus giganteus (47.8% and Mycenas rosea (44.8% presented the highest inhibition of biofilm formation. The extracts exhibiting the highest inhibitory effect upon P. mirabilis biofilm formation were Sarcodon imbricatus (45.4% and Russula delica (53.1%. Acinetobacter baumannii was the microorganism with the lowest susceptibility to mushroom extracts inhibitory effect on biofilm production (highest inhibition—almost 29%, by Russula delica extract. This is a pioneer study since, as far as we know, there are no reports on the inhibition of biofilm production by the studied mushroom extracts and in particular against multi-resistant clinical isolates; nevertheless, other

  9. Airway biofilms: implications for pathogenesis and therapy of respiratory tract infections.

    Science.gov (United States)

    Kobayashi, Hiroyuki

    2005-01-01

    The differentiation of bacterial biofilms in the airway environment, the pathogenesis of airway biofilm, and possible therapeutic methods are discussed. Biofilm diseases that characteristically involve the respiratory system include cystic fibrosis (CF), diffuse panbronchiolitis (DPB), and bronchiectasia with Pseudomonas aeruginosa (P. aeruginosa) infection. There is evidence to suggest that almost all strains of P. aeruginosa have the genetic capacity to synthesize alginate, a main matrix of biofilms, when ecological conditions are unfavorable for their survival. The bacteria inside the mature biofilm show increased resistance to both antibacterials and phagocytic cells, express fewer virulence factors because of their stationary state of growth, and are less stimulatory to the mucosa because of the 'sandwich binding'. These factors facilitate both the colonization of bacteria and their extended survival even under unfavorable conditions. Since the biofilm limits colonization to a latent form, the clinical symptoms in this situation are unremarkable. However, the clinical progression of both CF and DPB proceeds in two characteristic directions. The first is an acute exacerbation caused by planktonic bacteria that have germinated from the biofilm. The second is a slow progression of disease that is induced by harmful immune reactions. The harmful reactions are mediated by alginate, which induces antigen antibody reactions around the airways, as well as formation of circulating immune complexes that are deposited on lung tissue. Furthermore, the highest titer of bacterial permeability increasing anti-neutrophil cytoplasmic autoantibodies (BPI-ANCA) is observed in association with highly impaired pulmonary function in patients with CF and DPB, as well as in patients with a lengthy period of colonization with P. aeruginosa. BPI-ANCA subsequently makes chronic airway infection even more intractable. The long-term use of 14- or 15-ring membered macrolides results in a

  10. 铜绿假单胞菌生物膜与亚抑菌浓度抗菌药物的相关研究%Effect of subinhibitory concentrations on formation of biofilm of Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    李俊娟; 王强; 孙开宇; 蒋捍东

    2012-01-01

    OBJECTIVE To study the effects of the subinhibitory concentrations on the biofilm formation of Pseudomonas aeruginosa (PAE).- METHODS We first determined the minimal inhibitory concentration of azithromycin, amikacin, ciprofloxacin and ceftazidime of the PAE cultured in MHB and LB. We made the static biofilm model of P. aeruginosa in 96-well microtiter plates with the four antibiotics and medical silica gel with the azithromycin concentration, the OD value was determined with crystal violet staining microplate reader, and the biofilm was observed with silver staining microscope. RESULTS The MIC of azithromycin of PAE in MHB and LB were 512 mg/L and 16 mg/L, respectively; the MIC of amikacin, ciprofloxacin and ceftazidime of the PAE were 4 mg/L, 0. 125 mg/L and 4 mg/L, respectively; the results of the static-made biofilm were as follows: in the MHB and LB media, azithromycin could induce the biofilm formation of PAE at the subinhibitory concentration. Ciprofloxacin and ceftazidime could inhibit the biofilm formation at these concentrations. Amikacin could inhibit the biofilm formation at the concentration of 0. 25 to 4 mg/L (1/16MIC-MIC) , but could induce biofilm formation at the concentration of 0. 125 mg/L (1/16 MIC)in MHB; and when PAE was cultured in LB, amikacin could inhibit the biofilm formation at the concentration of 1 to 4 mg/L (1/4MIC-MIC) , and induce the biofilm formation at 0.25 mg/L(l/16MIC). All the results above had statistical differences compared with the control group. Silverstaining results: when the concentration of azithromycin was 8mg/L,the formation of the biofilm was the most, the second was the blank group and it was the least as the concentration was 256 mg/L. CONCLUSION The sensitivity of PAE planktonic bacteria to azithromycin varies in different culture condition; and the azithromycin may induce the biofilm formation at the subinhibitory concentration; ciprofloxacin and ceftazidime can inhibit the biofilm formation; the inhibitory of

  11. Presence of exoY, exoS, exoU and exoT genes, antibiotic resistance and biofilm production among Pseudomonas aeruginosa isolates in Northwest Iran

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    Azimi, Somayeh

    2016-02-01

    Full Text Available Background: , as Gram-negative rod bacilli, has an important role in human infection. In the present study we aimed to investigate the presence of genes and biofilm production among isolates in Northwest Iran.Material and methods: 160 isolates of were collected and identified by biochemical tests and were characterized for antibiotic resistance. Biofilm production was evaluated by microtiter plate assay and the presence of genes was evaluated by allele-specific PCR (polymerase chain reaction. Chi-square test was used for statistical analysis.Results: The most effective antibiotics against isolates were colistin and polymyxin B. 87% of the isolates were biofilm producers of which 69% were strongly biofilm producers. 55% of the isolates carried , 52% of the isolates carried , and 26.3% and 5% carried and , respectively.Conclusion: Our findings showed different distribution of genes in clinical isolates of in Northwest Iran. and were more prevalent in non-biofilm producers and was more prevalent in biofilm producer isolates. These results might indicate the importance of in biofilm production of .

  12. Comparison of quantification methods illustrates reduced Pseudomonas aeruginosa activity on nanorough polyvinyl chloride.

    Science.gov (United States)

    Seil, Justin T; Rubien, Nathan M; Webster, Thomas J; Tarquinio, Keiko M

    2011-07-01

    Patients on mechanical ventilators for extended periods of time are faced with a high probability of developing ventilator associated pneumonia. Although this has been mostly addressed through the re-engineering of endotracheal tubes (ETTs) with antimicrobial materials, such material coatings may easily delaminate during use. However, the potential exists to apply nanotechnology to the ETT to avoid delamination but implement antibacterial properties. Selecting a protocol to evaluate in vitro material for anti-infection is difficult, partially due to the existence of conflicting reported methods of analysis. In this study, the susceptibility of conventional and nanorough polymeric materials to bacterial biofilm growth were evaluated. After creating nanorough polyvinyl chloride (PVC) ETTs, Pseudomonas aeruginosa biofilms were then grown on sample surfaces during a 24-h culture. Biofilms were then removed and assayed from sample surfaces using a variety of techniques. Comparisons between the different techniques used for biofilm removal indicated that vortexing provided adequate removal of the biofilm from sample surfaces. Most importantly, a protocol following the vortexing method of biofilm and bacteria removal provided an ∼40% lower yield of colony forming units from nanorough PVC compared to conventional PVC. This suggests that Pseudomonas aeruginosa are less adherent on nanorough PVC than conventional PVC.

  13. Molecular Studies of Filamentous and Biofilm-Forming Hyperthermophilic Communities in Yellowstone National Park

    Science.gov (United States)

    Summons, R. E.; Meyer-Dombard, D. R.; Bradley, A. S.; Dibbell, A. K.; Fredricks, H. F.; Hinrichs, K.; Jahnke, L. L.; Shock, E.; Amend, J. P.

    2005-12-01

    The Aquificales, the most deeply-branching order of Bacteria in the phylogenetic tree of life, comprises eight recognized thermophilic genera, including Aquifex, Hydrogenobacter, and Thermocrinis. The common metabolism for these Bacteria, when grown in culture, is the oxidation of hydrogen with molecular oxygen (Knallgas reaction). Aquificales have been identified by molecular techniques (16S rRNA gene surveys, fluorescent in situ hybridization) in Yellowstone National Park (YNP), sea vent chimneys and fluids, and many other terrestrial and marine locations. In situ, Aquificales can reside as biofilms on vent sinters but they also commonly form filamentous communities, otherwise known as pink streamers, which attach to solid substrates. Initial 16S rRNA gene surveys conducted on streamer communities from Octopus Spring YNP indicated that these were low diversity ecosystems dominated by a few phylotypes including Thermocrinis sp., Thermotoga sp. and one other bacterial clade (Reysenbach et al 1994). Archaea were notable for their absence. In one of the first geobiological studies of pink streamers and vent biofilms in Yellowstone National Park, Jahnke and coworkers (2001) used classical lipidological techniques to compare Aquificales cultures with environmental samples to show that YNP pink filaments were more phylogenetically diverse and physiologically more complex than the early genomic studies indicated. The presence of archaeol, the range and structures of other lipids and a wide dispersion in the carbon isotopic signatures of biomass and individual lipids (-15 to -27%) showed that Archaea were present in pink filament communities and that there was, at least, one additional bacterial group besides the dominant Aquificales component. New molecular studies that comprise analyses of 16S rRNA genes and total lipid extracts by liquid chromatography and mass spectrometry and chemical degradation with gas chromatography and mass spectrometry now show that Crenarchaea

  14. Contamination potential of drinking water distribution network biofilms.

    Science.gov (United States)

    Wingender, J; Flemming, H C

    2004-01-01

    Drinking water distribution system biofilms were investigated for the presence of hygienically relevant microorganisms. Early biofilm formation was evaluated in biofilm reactors on stainless steel, copper, polyvinyl chloride (PVC) and polyethylene coupons exposed to unchlorinated drinking water. After 12 to 18 months, a plateau phase of biofilm development was reached. Surface colonization on the materials ranged between 4 x 10(6) and 3 x 10(7) cells/cm2, with heterotrophic plate count (HPC) bacteria between 9 x 10(3) and 7 x 10(5) colony-forming units (cfu)/cm2. Established biofilms were investigated in 18 pipe sections (2 to 99 years old) cut out from distribution pipelines. Materials included cast iron, galvanized steel, cement and PVC. Colonization ranged from 4 x 10(5) to 2 x 10(8) cells/cm2, HPC levels varied between 1 and 2 x 10(5) cfu/cm2. No correlation was found between extent of colonization and age of the pipes. Using cultural detection methods, coliform bacteria were rarely found, while Escherichia coli, Pseudomonas aeruginosa and Legionella spp. were not detected in the biofilms. In regular operation, distribution system biofilms do not seem to be common habitats for pathogens. However, nutrient-leaching materials like rubber-coated valves were observed with massive biofilms which harboured coliform bacteria contaminating drinking water. PMID:15303752

  15. Low power gas discharge plasma mediated inactivation and removal of biofilms formed on biomaterials.

    Science.gov (United States)

    Traba, Christian; Chen, Long; Liang, Jun F

    2013-03-20

    The antibacterial activity of gas discharge plasma has been studied for quiet some time. However, high biofilm inactivation activity of plasma was only recently reported. Studies indicate that the etching effect associated with plasmas generated represent an undesired effect, which may cause live bacteria relocation and thus contamination spreading. Meanwhile, the strong etching effects from these high power plasmas may also alter the surface chemistry and affect the biocompatibility of biomaterials. In this study, we examined the efficiency and effectiveness of low power gas discharge plasma for biofilm inactivation and removal. Among the three tested gases, oxygen, nitrogen, and argon, discharge oxygen demonstrated the best anti-biofilm activity because of its excellent ability in killing bacteria in biofilms and mild etching effects. Low power discharge oxygen completely killed and then removed the dead bacteria from attached surface but had negligible effects on the biocompatibility of materials. DNA left on the regenerated surface after removal of biofilms did not have any negative impact on tissue cell growth. On the contrary, dramatically increased growth was found for these cells seeded on regenerated surfaces. These results demonstrate the potential applications of low power discharge oxygen in biofilm treatments of biomaterials and indwelling device decontaminations.

  16. 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.

  17. Influence of papain in biofilm formed by methicillin-resistant Staphylococcus epidermidis and methicillin-resistant Staphylococcus haemolyticus isolates

    OpenAIRE

    Hanna Lara da Cruz Dinéas de Oliveira; Maria Emília de Castro Kling Fleming; Patrícia Vollu Silva; Geraldo Renato de Paula; Débora Omena Futuro; Guillermo Coca Velarde; Luciana Maria Ramires Esper; Lenise Arneiro Teixeira

    2014-01-01

    Methicillin-resistant Staphylococcus epidermidis (MRSE) and methicillin-resistant Staphylococcus haemolyticus (MRSHa) are important coagulase-negative staphylococci. They are often isolated from bacteremia in humans mainly due to their ability to form biofilm on the surfaces of medical devices. Papain is a complex mixture of proteolytic enzymes and peroxidases extracted from the latex of Carica papaya and it is recognized by accelerating the healing process of wounds. This study aimed to eval...

  18. [Genetic identification and study of the ability of lactobacilli isolated from the oral cavity of healthy individuals to form biofilms].

    Science.gov (United States)

    Chervinets, Iu V; Botina, S G; Glazova, A A; Koroban, N V; Chervinets, V M; Samoukina, A M; Gavrilova, O A; Lebedev, D V; Mironov, A Iu

    2011-02-01

    The highly antagonistic lactobacillus strains isolated from the oral cavity of human individuals were genetically passported as L. fermentum 39, L. rhamnosus 50, and L. rhamnosus 24, by applying the RAPD-PCR technique with two types of primers (M13, MSP). These lactobacillus strains showed high degrees of autoaggregation, surface hydrophobicity, coaggregation, and adhesion. These characteristics determine the obvious capacity of lactobacilli to form biofilms, which may be used to design new probiotic agents.

  19. Type III Secretion System Translocon Component EseB Forms Filaments on and Mediates Autoaggregation of and Biofilm Formation by Edwardsiella tarda.

    Science.gov (United States)

    Gao, Zhi Peng; Nie, Pin; Lu, Jin Fang; Liu, Lu Yi; Xiao, Tiao Yi; Liu, Wei; Liu, Jia Shou; Xie, Hai Xia

    2015-09-01

    The type III secretion system (T3SS) of Edwardsiella tarda plays an important role in infection by translocating effector proteins into host cells. EseB, a component required for effector translocation, is reported to mediate autoaggregation of E. tarda. In this study, we demonstrate that EseB forms filamentous appendages on the surface of E. tarda and is required for biofilm formation by E. tarda in Dulbecco's modified Eagle's medium (DMEM). Biofilm formation by E. tarda in DMEM does not require FlhB, an essential component for assembling flagella. Dynamic analysis of EseB filament formation, autoaggregation, and biofilm formation shows that the formation of EseB filaments occurs prior to autoaggregation and biofilm formation. The addition of an EseB antibody to E. tarda cultures before bacterial autoaggregation prevents autoaggregation and biofilm formation in a dose-dependent manner, whereas the addition of the EseB antibody to E. tarda cultures in which biofilm is already formed does not destroy the biofilm. Therefore, EseB filament-mediated bacterial cell-cell interaction is a prerequisite for autoaggregation and biofilm formation.

  20. A combination of cis-2-decenoic acid and antibiotics eradicates pre-established catheter-associated biofilms.

    Science.gov (United States)

    Rahmani-Badi, Azadeh; Sepehr, Shayesteh; Mohammadi, Parisa; Soudi, Mohammad Reza; Babaie-Naiej, Hamta; Fallahi, Hossein

    2014-11-01

    The catheterized urinary tract provides ideal conditions for the development of biofilm populations. Catheter-associated urinary tract infections (CAUTIs) are recalcitrant to existing antimicrobial treatments; therefore, established biofilms are not eradicated completely after treatment and surviving biofilm cells will carry on the infection. Cis-2-decenoic acid (CDA), an unsaturated fatty acid, is capable of inhibiting biofilm formation by Pseudomonas aeruginosa and of inducing the dispersion of established biofilms by multiple types of micro-organisms. Here, the ability of CDA to induce dispersal in pre-established single- and dual-species biofilms formed by Escherichia coli and Klebsiella pneumoniae was measured by using both semi-batch and continuous cultures bioassays. Removal of the biofilms by combined CDA and antibiotics (ciprofloxacin or ampicillin) was evaluated using microtitre plate assays (crystal violet staining). The c.f.u. counts were determined to assess the potential of combined CDA treatments to kill and eradicate pre-established biofilms formed on catheters. The effects of combined CDA treatments on biofilm surface area and bacteria viability were evaluated using fluorescence microscopy, digital image analysis and live/dead staining. To investigate the ability of CDA to prevent biofilm formation, single and mixed cultures were grown in the presence and absence of CDA. Treatment of pre-established biofilms with only 310 nM CDA resulted in at least threefold increase in the number of planktonic cells in all cultures tested. Whilst none of the antibiotics alone exerted a significant effect on c.f.u. counts and percentage of surface area covered by the biofilms, combined CDA treatments led to at least a 78% reduction in biofilm biomass in all cases. Moreover, most of the biofilm cells remaining on the surface were killed by antibiotics. The addition of 310 nM CDA significantly prevented biofilm formation by the tested micro-organisms, even within

  1. Destruction of oral biofilms formed in situ on machined titanium (Ti) surfaces by cold atmospheric plasma.

    Science.gov (United States)

    Idlibi, Ahmad Nour; Al-Marrawi, Fuad; Hannig, Matthias; Lehmann, Antje; Rueppell, Andre; Schindler, Axel; Jentsch, Holger; Rupf, Stefan

    2013-01-01

    The decontamination of implant surfaces represents the basic procedure in the management of peri-implant diseases, but it is still a challenge. The study aimed to evaluate the degradation of oral biofilms grown in situ on machined titanium (Ti) discs by cold atmospheric plasma (CAP). ~200 Ti discs were exposed to the oral cavities of five healthy human volunteers for 72 h. The resulting biofilms were divided randomly between the following treatments: CAP (which varied in mean power, treatment duration, and/or the gas mixture), and untreated and treated controls (diode laser, air-abrasion, chlorhexidine). The viability, quantity, and morphology of the biofilms were determined by live/dead staining, inoculation onto blood agar, quantification of the total protein content, and scanning electron microscopy. Exposure to CAP significantly reduced the viability and quantity of biofilms compared with the positive control treatments. The efficacy of treatment with CAP correlated with the treatment duration and plasma power. No single method achieved complete biofilm removal; however, CAP may provide an effective support to established decontamination techniques for treatment of peri-implant diseases.

  2. Effectiveness of Chitosan against Mature Biofilms Formed by Food Related Bacteria

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    Carmen San Jose

    2011-01-01

    Full Text Available Chitosan has proven antimicrobial properties against planktonic cell growth. Little is known, however, about its effects on already established biofilms. Oriented for application in food industry disinfection, the effectiveness of both medium molecular weight (MMW chitosan and its enzymatically hydrolyzed product was tested against mature biofilms of four pathogenic strains, Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus and Salmonella enterica, and a food spoilage species, Pseudomonas fluorescens. Unexpectedly, log reductions were in some cases higher for biofilm than for planktonic cells. One hour exposure to MMW chitosan (1% w/v caused a 6 log viable cell reduction on L. monocytogenes monospecies mature biofilms and reduced significantly (3–5 log reductions the attached population of the other organisms tested, except S. aureus. Pronase-treated chitosan was more effective than MMW chitosan on all tested microorganisms, also with the exception of S. aureus, offering best results (8 log units against the attached cells of B. cereus. These treatments open a new possibility to fight against mature biofilms in the food industry.

  3. Transfer of bacteria between stainless steel and chicken meat: A CLSM and DGGE study of biofilms

    Directory of Open Access Journals (Sweden)

    Christine C. Gaylarde

    2016-08-01

    Full Text Available This study aimed to assess the interaction between bacteria and food processing surfaces using novel methods. Microbial cross contamination between stainless steel, a common food processing material, and raw chicken was studied using microbiological culture, specialized microscope and molecular techniques. Confocal laser scanning microscopy (CLSM allowed the visualization of biofilms containing single or dual species of Escherichia coli O157:H7, Salmonella typhimurium, Bacillus cereus, Staphylococcus aureus and Pseudomonas aeruginosa, formed after 6 days’ incubation on stainless steel or 4h on raw chicken. The results provided information on intra-biofilm location and stratification of species within dual species biofilms. Top-to-bottom Z-stack images revealed that, on both materials, S. typhimurium and E. coli attached concurrently, the former in greater numbers. E. coli and B. cereus segregated on steel, E. coli more frequent near the metal surface, B. cereus almost the only species in outer layers. Few cells of S. aureus, found at all depths, were seen in the 2.9 µm thick biofilm on steel with E. coli. Greatest attachment was shown by P. aeruginosa, followed by S. typhimurium, E. coli and finally Gram positive species. Large amounts of EPS in P. aeruginosa biofilms made visualization difficult on both materials, but especially on chicken meat, a limitation of this technique. Nevertheless, CLSM was useful for determining time sequence of adhesion and species makeup of thin biofilms. The technique showed that five min contact between bacterially-contaminated chicken and sterile steel resulted in greatest transfer of P. aeruginosa, followed by S. typhimurium. This was confirmed using DGGE. Gram positive bacteria transferred poorly. A biofilm containing 2.3 × 105  cfu·cm−2 B. cereus on steel transferred an undetectable number of cells to chicken after 5 min contact. This species was unable to form biofilm on chicken when incubated for 4 h

  4. Catheter-related infections caused by Pseudomonas aeruginosa: virulence factors involved and their relationships.

    Science.gov (United States)

    Olejnickova, Katerina; Hola, Veronika; Ruzicka, Filip

    2014-11-01

    The nosocomial pathogen Pseudomonas aeruginosa is equipped with a large arsenal of cell-associated and secreted virulence factors which enhance its invasive potential. The complex relationships among virulence determinants have hitherto not been fully elucidated. In the present study, 175 catheter-related isolates were observed for the presence of selected virulence factors, namely extracellular enzymes and siderophore production, biofilm formation, resistance to antibiotics, and motility. A high percentage of the strains produced most of the tested virulence factors. A positive correlation was identified between the production of several exoproducts, and also between the formation of both types of biofilm. An opposite trend was observed between the two types of biofilm and the production of siderophores. Whereas the relationship between the submerged biofilm production (i.e. the biofilm formed on the solid surface below the water level) and the siderophore secretion was negative, the production of air-liquid interface (A-L) biofilm (i.e. the biofilm floating on the surface of the cultivation medium) and the siderophore secretion were positively correlated. All correlations were statistically significant at the level P = 0.05 with the correlation coefficient γ ≥ 0.50. Our results suggest that: (1) the co-production of the lytic enzymes and siderophores can play an important role in the pathogenesis of the catheter-related infections and should be taken into account when the virulence potential is assessed; (2) biofilm-positive strains are capable of forming both submerged and non-attached A-L biofilms; and (3) the different micro-environment in the submerged biofilm and A-L biofilm layers have opposite consequences for the production of other virulence factors.

  5. Catheter-related infections caused by Pseudomonas aeruginosa: virulence factors involved and their relationships.

    Science.gov (United States)

    Olejnickova, Katerina; Hola, Veronika; Ruzicka, Filip

    2014-11-01

    The nosocomial pathogen Pseudomonas aeruginosa is equipped with a large arsenal of cell-associated and secreted virulence factors which enhance its invasive potential. The complex relationships among virulence determinants have hitherto not been fully elucidated. In the present study, 175 catheter-related isolates were observed for the presence of selected virulence factors, namely extracellular enzymes and siderophore production, biofilm formation, resistance to antibiotics, and motility. A high percentage of the strains produced most of the tested virulence factors. A positive correlation was identified between the production of several exoproducts, and also between the formation of both types of biofilm. An opposite trend was observed between the two types of biofilm and the production of siderophores. Whereas the relationship between the submerged biofilm production (i.e. the biofilm formed on the solid surface below the water level) and the siderophore secretion was negative, the production of air-liquid interface (A-L) biofilm (i.e. the biofilm floating on the surface of the cultivation medium) and the siderophore secretion were positively correlated. All correlations were statistically significant at the level P = 0.05 with the correlation coefficient γ ≥ 0.50. Our results suggest that: (1) the co-production of the lytic enzymes and siderophores can play an important role in the pathogenesis of the catheter-related infections and should be taken into account when the virulence potential is assessed; (2) biofilm-positive strains are capable of forming both submerged and non-attached A-L biofilms; and (3) the different micro-environment in the submerged biofilm and A-L biofilm layers have opposite consequences for the production of other virulence factors. PMID:24842562

  6. Evaluation of antimicrobial efficacy of Triphala (an Indian Ayurvedic herbal formulation and 0.2% chlorhexidine against Streptococcus mutans biofilm formed on tooth substrate: An in vitro study

    Directory of Open Access Journals (Sweden)

    J Prabhakar

    2014-01-01

    Conclusion: Triphala showed statistically significant antibacterial activity against S. mutans biofilm formed on tooth substrate. The incorporation of Triphala in mouth rinse could prove to be effective in reducing S. mutans count in the oral cavity.

  7. Efficacy of Various Chemical Disinfectants on Biofilms Formed in Spacecraft Potable Water System Component

    Science.gov (United States)

    Wong, Willy; Garcia, Veronica; Castro, Victoria; Ott, Mark; Duane

    2009-01-01

    As the provision of potable water is critical for successful habitation of the International Space Station (ISS), life support systems were installed in December 2008 to recycle both humidity from the atmosphere and urine to conserve available water in the vehicle. Pre-consumption testing from the dispensing needle at the Potable Water Dispenser (PWD) indicated that bacterial concentrations exceeded the current ISS specifications of 50 colony forming units (CFU) per ml. Subsequent investigations revealed that a corrugated stainless steel flex hose upstream of the dispensing needle in the PWD was filled with non-sterile water and left at room temperature for over one month before launch. To simulate biofilm formation that was suspected in the flight system, sterile flex hoses were seeded with a consortium of bacterial isolates previously recovered from other ISS water systems, which included Ralstonia pickettii, Burkholderia multivorans, Caulobacter vibrioides., and Cupriavidus pauculus. After 5 days of incubation, these hoses were challenged with various chemical disinfectants including hydrogen peroxide, colloidal silver, and buffered pH solutions to determine the ability of the disinfectants to decrease and maintain bacterial concentrations below ISS specifications. Disinfection efficacy over time was measured by collecting daily heterotrophic plate counts following exposure to the disinfectants. A single flush with either 6% hydrogen peroxide solution or a mixture of 3% hydrogen peroxide and 400 ppb colloidal silver effectively reduced the bacterial concentrations to less than 1 CFU/ml for a period of up to 2 months. Testing results indicated that hydrogen peroxide and mixtures of hydrogen peroxide and colloidal silver have tremendous potential as alternative disinfectants for ISS water systems.

  8. Synthesis of 2(5H)-pyrrinones and the inhibitory effects on the Biofilms of P.aeruginosa in vitro%2(5H)-吡咯酮衍生物的合成及对铜绿假单胞菌生物膜的体外作用

    Institute of Scientific and Technical Information of China (English)

    郭嘉亮; 刘兆祥; 巢伟; 孙平华

    2013-01-01

    以乙酰乙酸乙酯为原料,设计合成2(5H)-吡咯酮及其衍生物,所得化合物经1H NMR、13C NMR、MS和元素分析等确证.通过扫描电镜观察2(5H)-吡咯酮对黏液型铜绿假单胞菌P.aeruginosa(PA)体外生物被膜(biofilms,BF)的影响,可见BF被破坏,基质样物变稀疏,细菌群聚大为降低.活性实验结果表明,2(5H)-吡咯酮类化合物具有一定的抑制细菌群体感应的能力.%A series of pyrroles and 2 (5H) -pyrrinones were successfully synthesized from ethyl aceto-acetate, and characterized by 'H NMR, 13C NMR, MS spectra and elemental analysis. Scanning electron microscope (SEM) was used to evaluate the effects of the 2 (5H) -pyrrolones on the quorum sensing (QS) system and the bacterial biofilm (BF) formation biofilm formation. The biofilms of P. aeruginosa were inhibited, the base became sparseness, and the swarming was decreased. The results of biological activity tests indicated that 2 (5H) -pyrrinones showed potent ability to inhibit the formation of bacterial biofilms.

  9. Periplasmic Domains of Pseudomonas aeruginosa PilN and PilO Form a Stable Heterodimeric Complex

    Energy Technology Data Exchange (ETDEWEB)

    Sampaleanu, L.M.; Bonanno, J.B.; Ayers, M.; Koo, J.; Tammam, S.; Burley, S.K.; Almo, S.C.; Burrows, L.L.; Howell, P.L.; (HSC); (Einstein); (McMaster U.); (Lilly)

    2010-01-12

    Type IV pili (T4P) are bacterial virulence factors responsible for attachment to surfaces and for twitching motility, a motion that involves a succession of pilus extension and retraction cycles. In the opportunistic pathogen Pseudomonas aeruginosa, the PilM/N/O/P proteins are essential for T4P biogenesis, and genetic and biochemical analyses strongly suggest that they form an inner-membrane complex. Here, we show through co-expression and biochemical analysis that the periplasmic domains of PilN and PilO interact to form a heterodimer. The structure of residues 69-201 of the periplasmic domain of PilO was determined to 2.2 {angstrom} resolution and reveals the presence of a homodimer in the asymmetric unit. Each monomer consists of two N-terminal coiled coils and a C-terminal ferredoxin-like domain. This structure was used to generate homology models of PilN and the PilN/O heterodimer. Our structural analysis suggests that in vivo PilN/O heterodimerization would require changes in the orientation of the first N-terminal coiled coil, which leads to two alternative models for the role of the transmembrane domains in the PilN/O interaction. Analysis of PilN/O orthologues in the type II secretion system EpsL/M revealed significant similarities in their secondary structures and the tertiary structures of PilO and EpsM, although the way these proteins interact to form inner-membrane complexes appears to be different in T4P and type II secretion. Our analysis suggests that PilN interacts directly, via its N-terminal tail, with the cytoplasmic protein PilM. This work shows a direct interaction between the periplasmic domains of PilN and PilO, with PilO playing a key role in the proper folding of PilN. Our results suggest that PilN/O heterodimers form the foundation of the inner-membrane PilM/N/O/P complex, which is critical for the assembly of a functional T4P complex.

  10. Inhibitory effect of N-acetylcysteine combined with ciprofloxacin on biofilms produced by Pseudomonas aeruginosa%N-乙酰半胱氨酸与环丙沙星联合对铜绿假单胞菌生物被膜的抑制作用

    Institute of Scientific and Technical Information of China (English)

    赵铁梅; 刘又宁

    2011-01-01

    目的 研究N-乙酰半胱氨酸(NAC)、环丙沙星(CIP)单用及二者联合对铜绿假单胞菌生物被膜的抑制作用.方法 扫描电镜(SEM)观察NAC、CIP单用及二者联合对铜绿假单胞菌PAO1生物被膜形态的影响;结晶紫染色法定量分析二者单用及联合对铜绿假单胞菌生物被膜的影响;噻唑兰法(MTT)法测定二者联用的活菌数.结果 SEM观察到NAC对铜绿假单胞菌PAO1生物被膜有破坏解离作用,与CIP有协同作用;结晶紫染色法定量分析显示铜绿假单胞菌生物被膜的OD值随NAC剂量增大而减小;CIP(8MIC)作用后铜绿假单胞菌生物被膜的OD值下降至对照的69.1%~97.9%;CIP合用0.5、5 mg/ml NAC后OD值分别下降至CIP单用的(54.7±7.7)%、(48.9±11.4)%;NAC和CIP单用,分别在2.5 mg/ml和2 MIC时对成熟被膜下细菌的杀菌作用差异有统计学意义(P<0.01),联合作用后NAC和CIP在0.5 mg/ml和1/2 MIC时即对被膜下细菌的杀菌作用差异有统计学意义(P<0.01).结论 NAC对铜绿假单胞菌生物被膜有破坏解离作用、对被膜下细菌有杀菌作用,并与CIP存在一定的协同作用.%OBJECTIVE To investigate the inhibitory effect of N-acetylcysteine (NAC), ciprofloxacin (CIP) and combination of the two on biofilms produced by Pseudomonas aeruginosa. METHODS The morphology of biofilms after treatment with NAC, CIP and NAC combined with CIP was observed by scanning electron microscope (SEM).' Quantitative analysis of effects of NAC, CIP, NAC+CIP on performed biofilms of P. Aeruginosa were assayed by the optical densities stained by crystal violet. Viable counts of bacteria in biofilms were determined by methylthiazolyldiphenyltetrazolium(MTT) assay. RESULTS When observed by using SEM, NAC detached mature P. Aeruginosa biofilms, and was' synergistic with ciprofloxacin. Assayed by the optical densities stained with crystal violet showed P, aeruginosa biofilms reduced when NAC used and proportional to NAC

  11. Biofilms and the survival of opportunistic pathogens in recycled water

    Science.gov (United States)

    Boyle, M.; Ford, T.; Maki, J. S.; Mitchell, R.

    1991-01-01

    Microorganisms are likely to develop an organic film on pipes, water reservoirs and filters used for waste water reclamation during extended missions in space. These biofilms can serve to protect and concentrate potentially pathogenic microorganisms. Our investigation has emphasized the survival strategy of opportunistic pathogenic bacteria in distilled water. Pseudomonas aeruginosa and Staphylococcus aureus were used as test organisms. Cultures were incubated at 10 degrees, 25 degrees, and 37 degrees C. No viable Staphylococcus cells were detected after the first week of incubation. P. aeruginosa, however, survived in distilled water up to 5 months at all three temperatures tested. The starved cells were able to form a biofilm layer on stainless steel. The cells exhibited a negative surface charge. The charge may be involved in the adhesion of this bacterium to metal substrata. We are currently investigating the importance of adhesion in the survival of this and other potential human pathogens found in water recycling systems.

  12. Anti-biofilm and anti-adherence activity of Glm-U inhibitors

    Directory of Open Access Journals (Sweden)

    Ethel Suman

    2011-01-01

    Full Text Available Background: Intravascular catheters and urinary catheters are an important source of hospital-acquired infections. Many microorganisms colonize indwelling catheters, including central venous catheters (CVCs forming biofilms and cause infections that are difficult to treat. Although various methods have been employed to reduce biofilms, enzymes involved in bacterial cell wall synthesis could provide novel targets for the development of anti-biofilm agents. N-Acetylglucosamine-1-phosphate uridyltransferase (GlmU is an essential enzyme in aminosugars metabolism and catalyzes the formation of uridine-diphospho-N-acetylglucosamine (UDP-GlcNAc, an important precursor in the peptidoglycan and lipopolysaccharide biosynthesis of Gram-positive and Gram-negative bacteria. Previous study has been conducted on the anti-biofilm effect of GlmU inhibitors such as N-ethyl maleimide (NEM and NEM analogs along with a cationic polypeptide protamine sulfate (PS, which enhanced its anti-biofilm activity. AIM: The present study aimed at finding the effect of sub-inhibitory concentrations of N-ethyl maleimide (NEM and protamine sulfate (PS on the biofilms produced by Pseudomonas aeruginosa and Enterococcus spp. isolated from cases of catheter-associated UTI as well as Klebsiella pneumoniae and Staphylococcus aureus isolated from cases of catheter-related bloodstream infections (CRBSI. Materials and Methods: In order to enhance the activity of NEM and to develop a broad-spectrum anti-microbial composition, NEM (50 μg/ml was combined with protamine sulfate (50 μg/ml and tested for anti-biofilm activity using a standard quantitative biofilm assay method. Results and Conclusion: It was observed that NEM had no effect on the biofilm produced by Pseudomonas aeruginosa as well as by Enterococcus spp. NEM also caused a significant decrease in biofilm production by Staphylococcus aureus while it had no effect on the biofilm produced by Klebsiella pneumoniae. There was a

  13. The in vivo biofilm

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Alhede, Maria; Alhede, Morten;

    2013-01-01

    Bacteria can grow and proliferate either as single, independent cells or organized in aggregates commonly referred to as biofilms. When bacteria succeed in forming a biofilm within the human host, the infection often becomes very resistant to treatment and can develop into a chronic state. Biofilms...... have been studied for decades using various in vitro models, but it remains debatable whether such in vitro biofilms actually resemble in vivo biofilms in chronic infections. In vivo biofilms share several structural characteristics that differ from most in vitro biofilms. Additionally, the in vivo...... experimental time span and presence of host defenses differ from chronic infections and the chemical microenvironment of both in vivo and in vitro biofilms is seldom taken into account. In this review, we discuss why the current in vitro models of biofilms might be limited for describing infectious biofilms...

  14. Tolerance to the antimicrobial peptide colistin in Pseudomonas aeruginosa biofilms is linked to metabolically active cells, and depends on the pmr and mexAB-oprM genes

    DEFF Research Database (Denmark)

    Pamp, Sünje Johanna; Gjermansen, Morten; Johansen, Helle Krogh;

    2008-01-01

    antimicrobial peptide colistin. On the contrary, biofilm cells exhibiting low metabolic activity were killed by colistin. We demonstrate that the subpopulation of metabolically active cells is able to adapt to colistin by inducing a specific adaptation mechanism mediated by the pmr operon, as well as an...... unspecific adaptation mechanism mediated by the mexAB-oprM genes. Mutants defective in either pmr-mediated lipopolysaccharide modification or in mexAB-oprM-mediated antimicrobial efflux were not able to develop a tolerant subpopulation in biofilms. In contrast to the observed pattern of colistin...... physiologically distinct subpopulations by combined antimicrobial treatment with either ciprofloxacin and colistin or tetracycline and colistin almost completely eradicated all biofilm cells....

  15. Bacterial communities in pigmented biofilms formed on the sandstone bas-relief walls of the Bayon Temple, Angkor Thom, Cambodia.

    Science.gov (United States)

    Kusumi, Asako; Li, Xianshu; Osuga, Yu; Kawashima, Arata; Gu, Ji-Dong; Nasu, Masao; Katayama, Yoko

    2013-01-01

    The Bayon temple in Angkor Thom, Cambodia has shown serious deterioration and is subject to the formation of various pigmented biofilms. Because biofilms are damaging the bas-reliefs, low reliefs engraved on the surface of sandstone, information about the microbial community within them is indispensable to control biofilm colonization. PCR-denaturing gradient gel electrophoresis (DGGE) analysis of biofilm samples from the pigmented sandstone surfaces showed that the bacterial community members in the biofilms differed clearly from those in the air and had low sequence similarity to database sequences. Non-destructive sampling of biofilm revealed novel bacterial groups of predominantly Rubrobacter in salmon pink biofilm, Cyanobacteria in chrome green biofilm, Cyanobacteria and Chloroflexi in signal violet biofilm, Chloroflexi in black gray biofilm, and Deinococcus-Thermus, Cyanobacteria, and Rubrobacter in blue green biofilm. Serial peeling-off of a thick biofilm by layers with adhesive sheets revealed a stratified structure: the blue-green biofilm, around which there was serious deterioration, was very rich in Cyanobacteria near the surface and Chloroflexi in deep layer below. Nitrate ion concentrations were high in the blue-green biofilm. The characteristic distribution of bacteria at different biofilm depths provides valuable information on not only the biofilm formation process but also the sandstone weathering process in the tropics.

  16. Microbial Diversity in the Early In Vivo-Formed Dental Biofilm.

    Science.gov (United States)

    Heller, D; Helmerhorst, E J; Gower, A C; Siqueira, W L; Paster, B J; Oppenheim, F G

    2016-03-01

    Although the mature dental biofilm composition is well studied, there is very little information on the earliest phase of in vivo tooth colonization. Progress in dental biofilm collection methodologies and techniques of large-scale microbial identification have made new studies in this field of oral biology feasible. The aim of this study was to characterize the temporal changes and diversity of the cultivable and noncultivable microbes in the early dental biofilm. Samples of early dental biofilm were collected from 11 healthy subjects at 0, 2, 4, and 6 h after removal of plaque and pellicle from tooth surfaces. With the semiquantitative Human Oral Microbiome Identification Microarray (HOMIM) technique, which is based on 16S rRNA sequence hybridizations, plaque samples were analyzed with the currently available 407 HOMIM microbial probes. This led to the identification of at least 92 species, with streptococci being the most abundant bacteria across all time points in all subjects. High-frequency detection was also made with Haemophilus parainfluenzae, Gemella haemolysans, Slackia exigua, and Rothia species. Abundance changes over time were noted for Streptococcus anginosus and Streptococcus intermedius (P = 0.02), Streptococcus mitis bv. 2 (P = 0.0002), Streptococcus oralis (P = 0.0002), Streptococcus cluster I (P = 0.003), G. haemolysans (P = 0.0005), and Stenotrophomonas maltophilia (P = 0.02). Among the currently uncultivable microbiota, eight phylotypes were detected in the early stages of biofilm formation, one belonging to the candidate bacterial division TM7, which has attracted attention due to its potential association with periodontal disease. PMID:26746720

  17. A study on the long term effect of biofilm produced by biosurfactant producing microbe on medical implant

    Energy Technology Data Exchange (ETDEWEB)

    Prabhawathi, Veluchamy; Thirunavukarasu, Kathirvel; Doble, Mukesh, E-mail: mukeshd@iitm.ac.in

    2014-07-01

    Low density polyethylene (LDPE) is used as a long term medical implant. Biofilm forming ability of two pathogenic microorganisms, namely, Bacillus subtilis (B. subtilis) and Pseudomonas aeruginosa (P. aeruginosa) on this polymer and the differences in the properties of these matrices are studied for a year. There are very few long term studies on biofilms formed on medical implants. After three months, colonies of B. subtilis were two times higher when compared to those of P. aeruginosa. And at the end of one year, they were two orders of magnitude higher than the later. The exopolysaccharide (EPS) and biosurfactant recovered from the polymer surface after three months were 21 and 10.4 μg/cm{sup 2} for B. subtilis and 13 and 8.6 μg/cm{sup 2} for P. aeruginosa. After one year, these were higher in B. subtilis (50 and 37.1 μg/cm{sup 2}, respectively) than in P. aeruginosa (34.1 and 31.8 μg/cm{sup 2}, respectively). B. subtilis consisted of protein controlling the community and sporulation development, while P. aeruginosa had either housekeeping or metabolic proteins. The EPS in the respective biofilm consisted of biosurfactants produced by B. subtilis (surfactins, m/z = 1029 to 1134) and P. aeruginosa (rhamnolipids, m/z = 568 to 705). Thermogravimetric analysis indicated that LDPE incubated with these organisms underwent a weight loss of 4 and 3% after three months and 11.1 and 9.2% after one year, respectively at 435 °C. Laccase and manganese peroxidase were detected in the biofilm which could be involved in the degradation. The biosurfactant of these microorganisms altered the hydrophobicity of the surface, favoring their attachment and proliferation. - Highlights: • Early P.aeru biofilm had genes needed for motility but later for housekeeping. • Early B. sub biofilm had genes needed for its formation but later for maturity. • Cells and matrix components in B. sub biofilm are higher than in P.aeru. • Compositions of these two biofilms are different.

  18. A study on the long term effect of biofilm produced by biosurfactant producing microbe on medical implant

    International Nuclear Information System (INIS)

    Low density polyethylene (LDPE) is used as a long term medical implant. Biofilm forming ability of two pathogenic microorganisms, namely, Bacillus subtilis (B. subtilis) and Pseudomonas aeruginosa (P. aeruginosa) on this polymer and the differences in the properties of these matrices are studied for a year. There are very few long term studies on biofilms formed on medical implants. After three months, colonies of B. subtilis were two times higher when compared to those of P. aeruginosa. And at the end of one year, they were two orders of magnitude higher than the later. The exopolysaccharide (EPS) and biosurfactant recovered from the polymer surface after three months were 21 and 10.4 μg/cm2 for B. subtilis and 13 and 8.6 μg/cm2 for P. aeruginosa. After one year, these were higher in B. subtilis (50 and 37.1 μg/cm2, respectively) than in P. aeruginosa (34.1 and 31.8 μg/cm2, respectively). B. subtilis consisted of protein controlling the community and sporulation development, while P. aeruginosa had either housekeeping or metabolic proteins. The EPS in the respective biofilm consisted of biosurfactants produced by B. subtilis (surfactins, m/z = 1029 to 1134) and P. aeruginosa (rhamnolipids, m/z = 568 to 705). Thermogravimetric analysis indicated that LDPE incubated with these organisms underwent a weight loss of 4 and 3% after three months and 11.1 and 9.2% after one year, respectively at 435 °C. Laccase and manganese peroxidase were detected in the biofilm which could be involved in the degradation. The biosurfactant of these microorganisms altered the hydrophobicity of the surface, favoring their attachment and proliferation. - Highlights: • Early P.aeru biofilm had genes needed for motility but later for housekeeping. • Early B. sub biofilm had genes needed for its formation but later for maturity. • Cells and matrix components in B. sub biofilm are higher than in P.aeru. • Compositions of these two biofilms are different. • So they need diverse

  19. Study on resistance of pseudomonas aeruginosa biofilm to different disinfectants%铜绿假单胞菌生物膜对不同消毒因子的抗力研究

    Institute of Scientific and Technical Information of China (English)

    陆龙喜; 陆烨; 林军明; 许激; 朱一凡

    2011-01-01

    OBJECTIVE To study the resistance of Psedomonas aeruginosa biofilm to different disinfectants.METHODS The resistance of artificially cultured biofilm to different disinfectants were tested by improved Brow