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Sample records for aerogenes pseudomonas aeruginosa

  1. Pseudomonas aeruginosa biofilms in disease.

    PubMed

    Mulcahy, Lawrence R; Isabella, Vincent M; Lewis, Kim

    2014-07-01

    Pseudomonas aeruginosa is a ubiquitous organism that is the focus of intense research because of its prominent role in disease. Due to its relatively large genome and flexible metabolic capabilities, this organism exploits numerous environmental niches. It is an opportunistic pathogen that sets upon the human host when the normal immune defenses are disabled. Its deadliness is most apparent in cystic fibrosis patients, but it also is a major problem in burn wounds, chronic wounds, chronic obstructive pulmonary disorder, surface growth on implanted biomaterials, and within hospital surface and water supplies, where it poses a host of threats to vulnerable patients (Peleg and Hooper, N Engl J Med 362:1804-1813, 2010; Breathnach et al., J Hosp Infect 82:19-24, 2012). Once established in the patient, P. aeruginosa can be especially difficult to treat. The genome encodes a host of resistance genes, including multidrug efflux pumps (Poole, J Mol Microbiol Biotechnol 3:255-264, 2001) and enzymes conferring resistance to beta-lactam and aminoglycoside antibotics (Vahdani et al., Annal Burns Fire Disast 25:78-81, 2012), making therapy against this gram-negative pathogen particularly challenging due to the lack of novel antimicrobial therapeutics (Lewis, Nature 485: 439-440, 2012). This challenge is compounded by the ability of P. aeruginosa to grow in a biofilm, which may enhance its ability to cause infections by protecting bacteria from host defenses and chemotherapy. Here, we review recent studies of P. aeruginosa biofilms with a focus on how this unique mode of growth contributes to its ability to cause recalcitrant infections.

  2. Silver against Pseudomonas aeruginosa biofilms.

    PubMed

    Bjarnsholt, Thomas; Kirketerp-Møller, Klaus; Kristiansen, Søren; Phipps, Richard; Nielsen, Anne Kirstine; Jensen, Peter Østrup; Høiby, Niels; Givskov, Michael

    2007-08-01

    Silver has been recognized for its antimicrobial properties for centuries. Most studies on the antibacterial efficacy of silver, with particular emphasis on wound healing, have been performed on planktonic bacteria. Our recent studies, however, strongly suggest that colonization of wounds involves 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 mug/mL silver sulfadiazine eradicated the biofilm whereas a lower concentration (1 mug/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 primarily colonized either by biofilm-forming or planktonic bacteria.

  3. Antibiotic Conditioned Growth Medium of Pseudomonas Aeruginosa

    ERIC Educational Resources Information Center

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

    2004-01-01

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

  4. Composition of Pseudomonas aeruginosa slime

    PubMed Central

    Brown, M. R. W.; Foster, J. H. Scott; Clamp, J. R.

    1969-01-01

    1. The slime produced by eight strains of Pseudomonas aeruginosa on a number of different media was demonstrated to be qualitatively the same. Small quantitative differences may be occasioned by differences in the extraction procedure, the growth medium or the strain of organism used. 2. The slime was shown to be predominantly polysaccharide with some nucleic acid material and a small amount of protein. 3. The hydrolysed polysaccharide fraction consists mainly of glucose with smaller amounts of mannose. This accounts for some 50–60% of the total slime. In addition, there is some 5% of hyaluronic acid. The nucleic acid material represents approx. 20% of the total weight, and is composed of both RNA and DNA. 4. Minor components are protein, rhamnose and glucosamine, the protein being less than 5% of the total. 5. Hyaluronic acid is produced in greater quantities from nutrient broth than from chemically defined media, and is more firmly attached to the cells than the other components. PMID:4240755

  5. The Accessory Genome of Pseudomonas aeruginosa

    PubMed Central

    Kung, Vanderlene L.; Ozer, Egon A.; Hauser, Alan R.

    2010-01-01

    Summary: Pseudomonas aeruginosa strains exhibit significant variability in pathogenicity and ecological flexibility. Such interstrain differences reflect the dynamic nature of the P. aeruginosa genome, which is composed of a relatively invariable “core genome” and a highly variable “accessory genome.” Here we review the major classes of genetic elements comprising the P. aeruginosa accessory genome and highlight emerging themes in the acquisition and functional importance of these elements. Although the precise phenotypes endowed by the majority of the P. aeruginosa accessory genome have yet to be determined, rapid progress is being made, and a clearer understanding of the role of the P. aeruginosa accessory genome in ecology and infection is emerging. PMID:21119020

  6. Pseudomonas aeruginosa in Healthcare Settings

    MedlinePlus

    ... becoming more difficult to treat because of increasing antibiotic resistance. Selecting the right antibiotic usually requires that a ... to help educate people about Pseudomonas infections, and antibiotic resistance, and to encourage prevention activities and healthy behaviors ...

  7. Pseudomonas aeruginosa Dose-Response and Bathing Water Infection

    EPA Science Inventory

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

  8. Glycopeptide dendrimers as Pseudomonas aeruginosa biofilm inhibitors.

    PubMed

    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.

  9. Maintenance of chromosome structure in Pseudomonas aeruginosa

    PubMed Central

    Rybenkov, Valentin V.

    2014-01-01

    Replication and segregation of genetic information is an activity central to the well-being of all living cells. Concerted mechanisms have evolved that ensure that each cellular chromosome is replicated once and only once per cell cycle and then faithfully segregated into daughter cells. Despite remarkable taxonomic diversity, these mechanisms are largely conserved across eubacteria, although species specific distinctions can often be noted. Here, we provide an overview of the current state of knowledge about maintenance of the chromosome structure in Pseudomonas aeruginosa. We focus on global chromosome organization and its dynamics during DNA replication and cell division. Special emphasis is made on contrasting these activities in P. aeruginosa and other bacteria. Among unique P. aeruginosa features are the presence of two distinct autonomously replicating sequences and multiple condensins, which suggests existence of novel regulatory mechanisms. PMID:24863732

  10. Developing an international Pseudomonas aeruginosa reference panel

    PubMed Central

    De Soyza, Anthony; Hall, Amanda J; Mahenthiralingam, Eshwar; Drevinek, Pavel; Kaca, Wieslaw; Drulis-Kawa, Zuzanna; Stoitsova, Stoyanka R; Toth, Veronika; Coenye, Tom; Zlosnik, James E A; Burns, Jane L; Sá-Correia, Isabel; De Vos, Daniel; Pirnay, Jean-Paul; Kidd, Timothy J; Reid, David; Manos, Jim; Klockgether, Jens; Wiehlmann, Lutz; Tümmler, Burkhard; McClean, Siobhán; Winstanley, Craig

    2013-01-01

    Pseudomonas aeruginosa is a major opportunistic pathogen in cystic fibrosis (CF) patients and causes a wide range of infections among other susceptible populations. Its inherent resistance to many antimicrobials also makes it difficult to treat infections with this pathogen. Recent evidence has highlighted the diversity of this species, yet despite this, the majority of studies on virulence and pathogenesis focus on a small number of strains. There is a pressing need for a P. aeruginosa reference panel to harmonize and coordinate the collective efforts of the P. aeruginosa research community. We have collated a panel of 43 P. aeruginosa strains that reflects the organism's diversity. In addition to the commonly studied clones, this panel includes transmissible strains, sequential CF isolates, strains with specific virulence characteristics, and strains that represent serotype, genotype or geographic diversity. This focussed panel of P. aeruginosa isolates will help accelerate and consolidate the discovery of virulence determinants, improve our understanding of the pathogenesis of infections caused by this pathogen, and provide the community with a valuable resource for the testing of novel therapeutic agents. PMID:24214409

  11. Spaceflight Effects on Virulence of Pseudomonas Aeruginosa

    NASA Astrophysics Data System (ADS)

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

    2008-06-01

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

  12. Pseudomonas Aeruginosa: Resistance to the Max

    PubMed Central

    Poole, Keith

    2011-01-01

    Pseudomonas aeruginosa is intrinsically resistant to a variety of antimicrobials and can develop resistance during anti-pseudomonal chemotherapy both of which compromise treatment of infections caused by this organism. Resistance to multiple classes of antimicrobials (multidrug resistance) in particular is increasingly common in P. aeruginosa, with a number of reports of pan-resistant isolates treatable with a single agent, colistin. Acquired resistance in this organism is multifactorial and attributable to chromosomal mutations and the acquisition of resistance genes via horizontal gene transfer. Mutational changes impacting resistance include upregulation of multidrug efflux systems to promote antimicrobial expulsion, derepression of ampC, AmpC alterations that expand the enzyme's substrate specificity (i.e., extended-spectrum AmpC), alterations to outer membrane permeability to limit antimicrobial entry and alterations to antimicrobial targets. Acquired mechanisms contributing to resistance in P. aeruginosa include β-lactamases, notably the extended-spectrum β-lactamases and the carbapenemases that hydrolyze most β-lactams, aminoglycoside-modifying enzymes, and 16S rRNA methylases that provide high-level pan-aminoglycoside resistance. The organism's propensity to grow in vivo as antimicrobial-tolerant biofilms and the occurrence of hypermutator strains that yield antimicrobial resistant mutants at higher frequency also compromise anti-pseudomonal chemotherapy. With limited therapeutic options and increasing resistance will the untreatable P. aeruginosa infection soon be upon us? PMID:21747788

  13. Pseudomonas aeruginosa endophthalmitis masquerading as chronic uveitis

    PubMed Central

    Nagaraj, Kalpana Badami; Jayadev, Chaitra

    2013-01-01

    A 65-year-old male presented with decreased vision in the left eye of 15-day duration after having undergone an uneventful cataract surgery 10 months back. He had been previously treated with systemic steroids for recurrent uveitis postoperatively on three occasions in the same eye. B-scan ultrasonography showed multiple clumplike echoes suggestive of vitreous inflammation. Aqueous tap revealed Pseudomonas aeruginosa sensitive to ciprofloxacin. The patient was treated with intravitreal ciprofloxacin and vancomycin along with systemic ciprofloxacin with good clinical response. Even a virulent organism such as P.aeruginosa can present as a chronic uveitis, which, if missed, can lead to a delay in accurate diagnosis and appropriate management. PMID:23803484

  14. Pseudomonas aeruginosa ventilator-associated pneumonia management

    PubMed Central

    Ramírez-Estrada, Sergio; Borgatta, Bárbara; Rello, Jordi

    2016-01-01

    Ventilator-associated pneumonia is the most common infection in intensive care unit patients associated with high morbidity rates and elevated economic costs; Pseudomonas aeruginosa is one of the most frequent bacteria linked with this entity, with a high attributable mortality despite adequate treatment that is increased in the presence of multiresistant strains, a situation that is becoming more common in intensive care units. In this manuscript, we review the current management of ventilator-associated pneumonia due to P. aeruginosa, the most recent antipseudomonal agents, and new adjunctive therapies that are shifting the way we treat these infections. We support early initiation of broad-spectrum antipseudomonal antibiotics in present, followed by culture-guided monotherapy de-escalation when susceptibilities are available. Future management should be directed at blocking virulence; the role of alternative strategies such as new antibiotics, nebulized treatments, and vaccines is promising. PMID:26855594

  15. Risk assessment of Pseudomonas aeruginosa in water.

    PubMed

    Mena, Kristina D; Gerba, Charles P

    2009-01-01

    from ingesting P. aeruginosa in drinking water is low. The risk is slightly higher if the subject is taking an antibiotic resisted by P. aeruginosa. The fact that individuals on ampicillin are more susceptible to Pseudomonas gastrointestinal infection probably results from suppression of normal intestinal flora, which would allow Pseudomonas to colonize. The process of estimating risk was significantly constrained because of the absence of specific (quantitative) occurrence data for Pseudomonas. Sensitivity analysis shows that the greatest source of variability/uncertainty in the risk assessment is from the density distribution in the exposure rather than the dose-response or water consumption distributions. In summary, two routes appear to carry the greatest health risks from contacting water contaminated with P. aeruginosa (1) skin exposure in hot tubs and (2) lung exposure from inhaling aerosols.

  16. The Pseudomonas aeruginosa Proteome during Anaerobic Growth‡

    PubMed Central

    Wu, Manhong; Guina, Tina; Brittnacher, Mitchell; Nguyen, Hai; Eng, Jimmy; Miller, Samuel I.

    2005-01-01

    Isotope-coded affinity tag analysis and two-dimensional gel electrophoresis followed by tandem mass spectrometry were used to identify Pseudomonas aeruginosa proteins expressed during anaerobic growth. Out of the 617 proteins identified, 158 were changed in abundance during anaerobic growth compared to during aerobic growth, including proteins whose increased expression was expected based on their role in anaerobic metabolism. These results form the basis for future analyses of alterations in bacterial protein content during growth in various environments, including the cystic fibrosis airway. PMID:16291692

  17. Cryptic transposable phages of Pseudomonas aeruginosa

    SciTech Connect

    Krylov, V.N.; Mit`kina, L.N.; Pleteneva, E.A.; Aleshin, V.V.

    1995-11-01

    Frequencies of nucleotide sequences homologous to phage transposons (PT) of two species, D3112 and B3, were assessed in genomes of natural Pseudomonas aeruginosa strains by the dot-blot hybridization method. These strains were incapable of liberating viable phages on a lawn of the PA01 standard indicator strain of P. aeruginosa. It was shown that the homologies detected belong to two groups, high and intermediate, with respect to homology level. Homology patterns were classified as high when they provided signals comparable to those for hybridization in a positive control; patterns were classified as intermediate when the hybridization level was higher than the background level, but lower than in the positive control. Homologous PT sequences were designated as cryptic PT. Intact cryptic PT prophages were shown to exist in genomes of particular natural strains manifesting a higher level of hybridization. However, the growth of these phages was limited by the restriction system of strain PA01. It is possible to isolate strains maintaining the growth of some cryptic PT. These strains differed from P. aeruginosa with respect to the specificity of the restriction and modification system. Nevertheless, in most cases, the attempt to identify a novel host capable of maintaining growth of a cryptic PT failed. Natural strains often carry cryptic PT related to both known PT species, D3112 and B3. The frequency of cryptic PT is extremely high, reaching 30% in strains with a high level of homology only and up to 50% in all strains exhibiting homology. This high PT frequency is assumed to be associated with the considerable variation of P. aeruginosa. 15 refs., 1 fig., 2 tabs.

  18. Pseudomonas aeruginosa Genomic Structure and Diversity

    PubMed Central

    Klockgether, Jens; Cramer, Nina; Wiehlmann, Lutz; Davenport, Colin F.; Tümmler, Burkhard

    2011-01-01

    The Pseudomonas aeruginosa genome (G + C content 65–67%, size 5.5–7 Mbp) is made up of a single circular chromosome and a variable number of plasmids. Sequencing of complete genomes or blocks of the accessory genome has revealed that the genome encodes a large repertoire of transporters, transcriptional regulators, and two-component regulatory systems which reflects its metabolic diversity to utilize a broad range of nutrients. The conserved core component of the genome is largely collinear among P. aeruginosa strains and exhibits an interclonal sequence diversity of 0.5–0.7%. Only a few loci of the core genome are subject to diversifying selection. Genome diversity is mainly caused by accessory DNA elements located in 79 regions of genome plasticity that are scattered around the genome and show an anomalous usage of mono- to tetradecanucleotides. Genomic islands of the pKLC102/PAGI-2 family that integrate into tRNALys or tRNAGly genes represent hotspots of inter- and intraclonal genomic diversity. The individual islands differ in their repertoire of metabolic genes that make a large contribution to the pangenome. In order to unravel intraclonal diversity of P. aeruginosa, the genomes of two members of the PA14 clonal complex from diverse habitats and geographic origin were compared. The genome sequences differed by less than 0.01% from each other. One hundred ninety-eight of the 231 single nucleotide substitutions (SNPs) were non-randomly distributed in the genome. Non-synonymous SNPs were mainly found in an integrated Pf1-like phage and in genes involved in transcriptional regulation, membrane and extracellular constituents, transport, and secretion. In summary, P. aeruginosa is endowed with a highly conserved core genome of low sequence diversity and a highly variable accessory genome that communicates with other pseudomonads and genera via horizontal gene transfer. PMID:21808635

  19. Vesiculation from Pseudomonas aeruginosa under SOS

    PubMed Central

    Maredia, Reshma; Devineni, Navya; Lentz, Peter; Dallo, Shatha F.; Yu, JiehJuen; Guentzel, Neal; Chambers, James; Arulanandam, Bernard; Haskins, William E.; Weitao, Tao

    2012-01-01

    Bacterial infections can be aggravated by antibiotic treatment that induces SOS response and vesiculation. This leads to a hypothesis concerning association of SOS with vesiculation. To test it, we conducted multiple analyses of outer membrane vesicles (OMVs) produced from the Pseudomonas aeruginosa wild type in which SOS is induced by ciprofloxacin and from the LexA noncleavable (lexAN) strain in which SOS is repressed. The levels of OMV proteins, lipids, and cytotoxicity increased for both the treated strains, demonstrating vesiculation stimulation by the antibiotic treatment. However, the further increase was suppressed in the lexAN strains, suggesting the SOS involvement. Obviously, the stimulated vesiculation is attributed by both SOS-related and unrelated factors. OMV subproteomic analysis was performed to examine these factors, which reflected the OMV-mediated cytotoxicity and the physiology of the vesiculating cells under treatment and SOS. Thus, SOS plays a role in the vesiculation stimulation that contributes to cytotoxicity. PMID:22448133

  20. Isolation of oxidase-negative Pseudomonas aeruginosa from sputum culture.

    PubMed Central

    Hampton, K D; Wasilauskas, B L

    1979-01-01

    Two isolates of Pseudomonas aeruginosa lacking characteristic indophenol oxidase were recovered from a sputum specimen. A discussion of the characteristic biochemical tests and antibiograms along with a possible explanation for this phenomenon is presented. PMID:225349

  1. Two unusual pilin sequences from different isolates of Pseudomonas aeruginosa.

    PubMed Central

    Pasloske, B L; Sastry, P A; Finlay, B B; Paranchych, W

    1988-01-01

    The pilin genes of two Pseudomonas aeruginosa strains isolated from two different patients with cystic fibrosis were cloned and sequenced. The predicted protein sequences of these two pilins had several unusual features compared with other published P. aeruginosa pilin sequences. PMID:2841299

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

    PubMed Central

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

    1989-01-01

    The effect of the addition of a recombinant plasmid containing the pglA gene encoding an alpha-1,4-endopolygalacturonase from Pseudomonas solanacearum on the growth of Pseudomonas aeruginosa and Pseudomonas putida in soil and rhizosphere was determined. Despite a high level of polygalacturonase production by genetically engineered P. putida and P. aeruginosa, the results suggest that polygalacturonase production had little effect on the growth of these strains in soil or rhizosphere. PMID:2515805

  3. The Regulatory Network of Pseudomonas aeruginosa

    PubMed Central

    2011-01-01

    Background Pseudomonas aeruginosa is an important bacterial model due to its metabolic and pathogenic abilities, which allow it to interact and colonize a wide range of hosts, including plants and animals. In this work we compile and analyze the structure and organization of an experimentally supported regulatory network in this bacterium. Results The regulatory network consists of 690 genes and 1020 regulatory interactions between their products (12% of total genes: 54% sigma and 16% of transcription factors). This complex interplay makes the third largest regulatory network of those reported in bacteria. The entire network is enriched for activating interactions and, peculiarly, self-activation seems to occur more prominent for transcription factors (TFs), which contrasts with other biological networks where self-repression is dominant. The network contains a giant component of 650 genes organized into 11 hierarchies, encompassing important biological processes, such as, biofilms formation, production of exopolysaccharide alginate and several virulence factors, and of the so-called quorum sensing regulons. Conclusions The study of gene regulation in P. aeruginosa is biased towards pathogenesis and virulence processes, all of which are interconnected. The network shows power-law distribution -input degree -, and we identified the top ten global regulators, six two-element cycles, the longest paths have ten steps, six biological modules and the main motifs containing three and four elements. We think this work can provide insights for the design of further studies to cover the many gaps in knowledge of this important bacterial model, and for the design of systems strategies to combat this bacterium. PMID:22587778

  4. Ambroxol interferes with Pseudomonas aeruginosa quorum sensing.

    PubMed

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

    2010-09-01

    The mucolytic agent ambroxol has been reported to interfere with the formation of Pseudomonas aeruginosa-derived biofilms in addition to reducing alginate production by undefined mechanisms. Since quorum sensing is a key regulator of virulence and biofilm formation, we examined the effects of ambroxol on P. aeruginosa PAO1 wild-type bacterial clearance rates, adhesion profiles and biofilm formation compared with the quorum sensing-deficient, double-mutant strains DeltalasR DeltarhlR and DeltalasI DeltarhlI. Data presented in this report demonstrated that ambroxol treatment reduced survival rates of the double-mutant strains compared with the wild-type strain in a dose-dependent manner even though the double-mutants had increased adhesion in the presence of ambroxol compared with the wild-type strain. The PAO1 wild-type strain produced a significantly thicker biofilm (21.64+/-0.57 microm) compared with the biofilms produced by the DeltalasR DeltarhlR (7.36+/-0.2 microm) and DeltalasI DeltarhlI (6.62+/-0.31 microm) isolates. Ambroxol treatment reduced biofilm thickness, increased areal porosity, and decreased the average diffusion distance and textual entropy of wild-type and double-mutant strains. However, compared with the double-mutant strains, the changes observed for the wild-type strain were more clearly defined. Finally, ambroxol exhibited significant antagonistic quorum-sensing properties, suggesting that it could be adapted for use clinically in the treatment of cystic fibrosis and to reduce biofilm formation and in the colonisation of indwelling devices. PMID:20580207

  5. Ambroxol interferes with Pseudomonas aeruginosa quorum sensing.

    PubMed

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

    2010-09-01

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

  6. Microbial degradation of quinoline and methylquinolines. [Pseudomonas aeruginosa

    SciTech Connect

    Aislabie, J.; Bej, A.K.; Hurst, H.; Rothenburger, S.; Atlas, R.M. )

    1990-02-01

    Several bacterial cultures were isolated that are able to degrade quinoline and to transform or to degrade methylquinolines. The degradation of quinoline by strains of Pseudomonas aeruginosa QP and Pseudomonas. putida QP produced hydroxyquinolines, a transient pink compound, and other undetermined products. The quinoline-degrading strains of P. aeruginosa QP and P. putida QP hydroxylated a limited number of methylquinolines but could not degrade them, nor could they transform 2-methylquinoline, isoquinoline, or pyridine. Another pseudomonad, Pseudomonas sp. strain MQP, was isolated that could degrade 2-methylquinoline. P. aeruginosa QP was able to degrade or to transform quinoline and a few methylquinolines in a complex heterocyclic nitrogen-containing fraction of a shale oil. All of the quinoline- and methylquinoline-degrading strains have multiple plasmids including a common 250-kilobase plasmid. The 225-, 250-, and 320-kilobase plasmids of the P. aeruginosa QP strain all contained genes involved in quinoline metabolism.

  7. Spontaneous release of lipopolysaccharide by Pseudomonas aeruginosa.

    PubMed Central

    Cadieux, J E; Kuzio, J; Milazzo, F H; Kropinski, A M

    1983-01-01

    Pseudomonas aeruginosa PAO grown in glucose mineral salts medium released lipopolysaccharide which was chemically and immunologically similar to the cellular lipopolysaccharide. In addition, it possessed identical phage E79-inactivating properties. Through neutralization of phage activity and hemolysis inhibition assays, the organism was found to liberate lipopolysaccharide at a constant rate during log-phase growth equivalent to 1.3 to 2.2 ng/10(8) cells over a growth temperature range of 25 to 42 degrees C. At 19 degrees C, a lipopolysaccharide was released which was deficient in phage-inactivating activity but retained its immunological properties. Chemical analysis of lipopolysaccharide extracted from cells grown at 19 degrees C showed a deficiency in the O-side-chain component fucosamine. Gel exclusion chromatography of the polysaccharide fraction derived from lipopolysaccharide isolated from cells grown at 19 degrees C exhibited a decreased content of side-chain polysaccharide as well as a difference in the hexosamine:hexose ratio. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis confirmed these results as well as establishing that an essentially normal distribution of side-chain repeating unit lengths were to be found in the 19 degrees C preparation. These results suggest a decrease in the frequency of capping R-form lipopolysaccharide at 19 degrees C. Images PMID:6409883

  8. Spaceflight promotes biofilm formation by Pseudomonas aeruginosa.

    PubMed

    Kim, Wooseong; Tengra, Farah K; Young, Zachary; Shong, Jasmine; Marchand, Nicholas; Chan, Hon Kit; Pangule, Ravindra C; Parra, Macarena; Dordick, Jonathan S; Plawsky, Joel L; Collins, Cynthia H

    2013-01-01

    Understanding the effects of spaceflight on microbial communities is crucial for the success of long-term, manned space missions. Surface-associated bacterial communities, known as biofilms, were abundant on the Mir space station and continue to be a challenge on the International Space Station. The health and safety hazards linked to the development of biofilms are of particular concern due to the suppression of immune function observed during spaceflight. While planktonic cultures of microbes have indicated that spaceflight can lead to increases in growth and virulence, the effects of spaceflight on biofilm development and physiology remain unclear. To address this issue, Pseudomonas aeruginosa was cultured during two Space Shuttle Atlantis missions: STS-132 and STS-135, and the biofilms formed during spaceflight were characterized. Spaceflight was observed to increase the number of viable cells, biofilm biomass, and thickness relative to normal gravity controls. Moreover, the biofilms formed during spaceflight exhibited a column-and-canopy structure that has not been observed on Earth. The increase in the amount of biofilms and the formation of the novel architecture during spaceflight were observed to be independent of carbon source and phosphate concentrations in the media. However, flagella-driven motility was shown to be essential for the formation of this biofilm architecture during spaceflight. These findings represent the first evidence that spaceflight affects community-level behaviors of bacteria and highlight the importance of understanding how both harmful and beneficial human-microbe interactions may be altered during spaceflight. PMID:23658630

  9. Glycerol metabolism promotes biofilm formation by Pseudomonas aeruginosa.

    PubMed

    Scoffield, Jessica; Silo-Suh, Laura

    2016-08-01

    Pseudomonas aeruginosa causes persistent infections in the airways of cystic fibrosis (CF) patients. Airway sputum contains various host-derived nutrients that can be utilized by P. aeruginosa, including phosphotidylcholine, a major component of host cell membranes. Phosphotidylcholine can be degraded by P. aeruginosa to glycerol and fatty acids to increase the availability of glycerol in the CF lung. In this study, we explored the role that glycerol metabolism plays in biofilm formation by P. aeruginosa. We report that glycerol metabolism promotes biofilm formation by both a chronic CF isolate (FRD1) and a wound isolate (PAO1) of P. aeruginosa. Moreover, loss of the GlpR regulator, which represses the expression of genes involved in glycerol metabolism, enhances biofilm formation in FRD1 through the upregulation of Pel polysaccharide. Taken together, our results suggest that glycerol metabolism may be a key factor that contributes to P. aeruginosa persistence by promoting biofilm formation.

  10. Nosocomial infections due to Pseudomonas aeruginosa: review of recent trends.

    PubMed

    Cross, A; Allen, J R; Burke, J; Ducel, G; Harris, A; John, J; Johnson, D; Lew, M; MacMillan, B; Meers, P

    1983-01-01

    The role of Pseudomonas aeruginosa in nosocomial infections occurring since 1975 is reviewed. Data from the National Nosocomial Infections Study conducted by the Centers for Disease Control, from individual medical centers, and from the literature were used to compare the relative frequency of occurrence of nosocomial infection caused by P. aeruginosa with that of infection caused by other gram-negative bacilli. The relative frequency of P. aeruginosa as a nosocomial pathogen has increased, although wide variations are seen among individual medical centers. P. aeruginosa continues to be a major pathogen among patients with immunosuppression, cystic fibrosis, malignancy, and trauma. While Staphylococcus aureus has become the predominant pathogen in some large burn centers, P. aeruginosa is the most important gram-negative pathogen. Periodic review of the epidemiology of P. aeruginosa infection is warranted in view of the changing incidence of infection caused by this organism.

  11. Glycerol metabolism promotes biofilm formation by Pseudomonas aeruginosa.

    PubMed

    Scoffield, Jessica; Silo-Suh, Laura

    2016-08-01

    Pseudomonas aeruginosa causes persistent infections in the airways of cystic fibrosis (CF) patients. Airway sputum contains various host-derived nutrients that can be utilized by P. aeruginosa, including phosphotidylcholine, a major component of host cell membranes. Phosphotidylcholine can be degraded by P. aeruginosa to glycerol and fatty acids to increase the availability of glycerol in the CF lung. In this study, we explored the role that glycerol metabolism plays in biofilm formation by P. aeruginosa. We report that glycerol metabolism promotes biofilm formation by both a chronic CF isolate (FRD1) and a wound isolate (PAO1) of P. aeruginosa. Moreover, loss of the GlpR regulator, which represses the expression of genes involved in glycerol metabolism, enhances biofilm formation in FRD1 through the upregulation of Pel polysaccharide. Taken together, our results suggest that glycerol metabolism may be a key factor that contributes to P. aeruginosa persistence by promoting biofilm formation. PMID:27392247

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

    Dyson, Zoe A; Seviour, Robert J; Tucci, Joseph; Petrovski, Steve

    2016-06-16

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

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

    PubMed

    Dyson, Zoe A; Seviour, Robert J; Tucci, Joseph; Petrovski, Steve

    2016-01-01

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

  15. Subtilase SprP exerts pleiotropic effects in Pseudomonas aeruginosa.

    PubMed

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

    2014-02-01

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

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

    PubMed

    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.

  17. Pyochelin potentiates the inhibitory activity of gallium on Pseudomonas aeruginosa.

    PubMed

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

    2014-09-01

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

  18. Pyochelin potentiates the inhibitory activity of gallium on Pseudomonas aeruginosa.

    PubMed

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

    2014-09-01

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

  19. Die-off and survival of Pseudomonas aeruginosa in freshwater.

    PubMed

    de Vicente, A; Aviles, M; Borrego, J J; Romero, P

    1988-03-01

    Studies of the survival of Pseudomonas aeruginosa in freshwater, in situ and in the laboratory, were carried out. A die-off of P. aeruginosa very similar to those of the microbial indicators of fecal pollution, especially to the coliforms, was observed from the results obtained by in situ experiments. The laboratory studies show that the factors tested which exert the greatest effect on the survival of P. aeruginosa in freshwater are the luminous radiations and non-filtrable biotic factors. Furthermore, a negative effect on the viability of this microorganism in freshwater is observed when sewage is added. PMID:3131996

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

    PubMed Central

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

    2015-01-01

    The development of new approaches for the treatment of antimicrobial-resistant infections is an urgent public health priority. The Pseudomonas aeruginosa pathogen, in particular, is a leading source of infection in hospital settings, with few available treatment options. In the context of an effort to develop antivirulence strategies to combat bacterial infection, we identified a series of highly effective small molecules that inhibit the production of pyocyanin, a redox-active virulence factor produced by P. aeruginosa. Interestingly, these new antagonists appear to suppress P. aeruginosa virulence factor production through a pathway that is independent of LasR and RhlR. PMID:25597392

  1. Production of Neisseria gonorrhoeae pili (fimbriae) in Pseudomonas aeruginosa.

    PubMed Central

    Hoyne, P A; Haas, R; Meyer, T F; Davies, J K; Elleman, T C

    1992-01-01

    Pseudomonas aeruginosa K/2PfS, when transformed with an expression plasmid harboring the pilin gene (pilE1) of Neisseria gonorrhoeae MS11, was able to express and assemble gonococcal pilin monomers into surface-associated pili, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, and immunoelectron microscopy. Concomitant with the expression of gonococcal pili in P. aeruginosa was the virtual loss of production of P. aeruginosa K/2PfS pili normally associated with the host cell. Images PMID:1358873

  2. Cloning of Pseudomonas aeruginosa algG, which controls alginate structure.

    PubMed Central

    Chitnis, C E; Ohman, D E

    1990-01-01

    The biochemical mechanism by which alpha-L-guluronate (G) residues are incorporated into alginate by Pseudomonas aeruginosa is not understood. P. aeruginosa first synthesizes GDP-mannuronate, which is used to incorporate beta-D-mannuronate residues into the polymer. It is likely that the conversion of some beta-D-mannuronate residues to G occurs by the action of a C-5 epimerase at either the monomer (e.g., sugar-nucleotide) or the polymer level. This study describes the results of a molecular genetic approach to identify a gene involved in the formation or incorporation of G residues into alginate by P. aeruginosa. Mucoid P. aeruginosa FRD1 was chemically mutagenized, and mutants FRD462 and FRD465, which were incapable of incorporating G residues into alginate, were independently isolated. Assays using a G-specific alginate lyase from Klebsiella aerogenes and 1H-nuclear magnetic resonance analyses showed that G residues were absent in the alginates secreted by these mutants. 1H-nuclear magnetic resonance analyses also showed that alginate from wild-type P. aeruginosa contained no detectable blocks of G. The mutations responsible for defective incorporation of G residues into alginate in the mutants FRD462 and FRD465 were designated algG4 and algG7, respectively. Genetic mapping experiments revealed that algG was closely linked (greater than 90%) to argF, which lies at 34 min on the P. aeruginosa chromosome and is adjacent to a cluster of genes required for alginate biosynthesis. The clone pALG2, which contained 35 kilobases of P. aeruginosa DNA that included the algG and argF wild-type alleles, was identified from a P. aeruginosa gene bank by a screening method that involved gene replacement. A DNA fragment carrying algG was shown to complement algG4 and algG7 in trans. The algG gene was physically mapped on the alginate gene cluster by subcloning and Tn501 mutagenesis. Images PMID:2160929

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

    PubMed Central

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

    2001-01-01

    Pseudomonas aeruginosa veterinary isolates were assayed for elastase and total matrix protease activity. The elastase activity of canine ear isolates was much less than that of strain PAO1 and that of all other veterinary isolates (P < 0.0001). The results indicate that canine ear isolates have a distinct elastase phenotype. PMID:11329471

  4. Global Pseudomonas aeruginosa biodiversity as reflected in a Belgian river.

    PubMed

    Pirnay, Jean-Paul; Matthijs, Sandra; Colak, Huri; Chablain, Patrice; Bilocq, Florence; Van Eldere, Johan; De Vos, Daniel; Zizi, Martin; Triest, Ludwig; Cornelis, Pierre

    2005-07-01

    The biodiversity of the bacterium Pseudomonas aeruginosa in an aquatic environment (the Woluwe River, Brussels, Belgium) was analysed. Surface water was sampled bimonthly over a 1-year period (2000-2001) at seven sites evenly dispersed over the river. Total bacterial counts were performed and P. aeruginosa strains were isolated on a selective medium. A weighed out sample of 100 randomly chosen presumptive P. aeruginosa isolates was further analysed. A set of data consisting of the nucleotide sequence of the oprL gene, a DNA-based fingerprint (amplified fragment length polymorphism, AFLP), serotype, pyoverdine type and antibiogram (MICs of 21 clinically relevant antibiotics) was assembled. These data were integrated with those previously obtained for 73 P. aeruginosa clinical and environmental isolates collected across the world. The combined results were analysed and compared using biological data analysis software. Our findings indicate a positive relationship between the extent of pollution and the prevalence of P. aeruginosa. Surprisingly, the Woluwe River P. aeruginosa community was almost as diverse as the global P. aeruginosa population. Indeed, the Woluwe River harboured members of nearly all successful clonal complexes. With the exception of one multidrug-resistant (MDR) strain, belonging to a ubiquitous and clinically relevant serotype O11 clone, antibiotic resistance levels were relatively low. These findings illustrate the significance of river water as a reservoir and source of distribution of potentially pathogenic P. aeruginosa strains and could have repercussions on antinosocomial infection strategies.

  5. Agricultural plants and soil as a reservoir for Pseudomonas aeruginosa.

    PubMed

    Green, S K; Schroth, M N; Cho, J J; Kominos, S K; Vitanza-jack, V B

    1974-12-01

    Pseudomonas aeruginosa was detected in 24% of the soil samples but in only 0.13% of the vegetable samples from various agricultural areas of California. The distribution of pyocin types of soil and vegetable isolates was similar to that of clinical strains, and three of the soil isolates were resistant to carbenicillin. Pseudomonas aeruginosa multiplied in lettuce and bean under conditions of high temperature and high relative humidity (27 C and 80-95% relative humidity) but declined when the temperature and humidity were lowered (16 C, 55-75% relative humidity). The results suggest that soil is a reservior for P. aeruginosa and that the bacterium has the capacity to colonize plants during favorable conditions of temperature and moisture. PMID:4217591

  6. Interspecies Interaction between Pseudomonas aeruginosa and Other Microorganisms

    PubMed Central

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

    2013-01-01

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

  7. Physiological responses of Microcystis aeruginosa against the algicidal bacterium Pseudomonas aeruginosa.

    PubMed

    Zhou, Su; Yin, Hua; Tang, Shaoyu; Peng, Hui; Yin, Donggao; Yang, Yixuan; Liu, Zehua; Dang, Zhi

    2016-05-01

    Proliferation of cyanobacteria in aquatic ecosystems has caused water security problems throughout the world. Our preliminary study has showed that Pseudomonas aeruginosa can inhibit the growth of cyanobacterium, Microcystis aeruginosa. In order to explore the inhibitory mechanism of P. aeruginosa on the cell growth and synthesis of intracellular substances of M. aeruginosa, concentrations of Chlorophyll-a, intracellular protein, carbohydrate, enzyme activities and ion metabolism of M. aeruginosa, were investigated. The results indicated that 83.84% algicidal efficiency of P. aeruginosa was achieved after treatment for 7 days. The strain inhibited the reproduction of M. aeruginosa by impeding the synthesis of intracellular protein and carbohydrate of cyanobacterium, and only a very small part of intracellular protein and carbohydrate was detected after exposure to P. aeruginosa for 5 days. P. aeruginosa caused the alteration of intracellular antioxidant enzyme activity of M. aeruginosa, such as catalase, peroxidase. The accumulation of malondialdehyde aggravated membrane injury after treatment for 3 days. P. aeruginosa also affected the ion metabolism of cyanobacteria. The release of Na(+) and Cl(-) was significantly enhanced while the uptake of K(+), Ca(2+), Mg(2+), NO3(-) and SO4(2)(-) decreased. Surface morphology and intracellular structure of cyanobacteria and bacterial cells changed dramatically over time as evidenced by electron microscope (SEM) and transmission electron microscope (TEM) analysis. These results revealed that the algicidal activity of P. aeruginosa was primarily due to the fermentation liquid of P. aeruginosa that impeded the synthesis of intracellular protein and carbohydrate, and damaged the cell membrane through membrane lipid peroxidation.

  8. Physiological responses of Microcystis aeruginosa against the algicidal bacterium Pseudomonas aeruginosa.

    PubMed

    Zhou, Su; Yin, Hua; Tang, Shaoyu; Peng, Hui; Yin, Donggao; Yang, Yixuan; Liu, Zehua; Dang, Zhi

    2016-05-01

    Proliferation of cyanobacteria in aquatic ecosystems has caused water security problems throughout the world. Our preliminary study has showed that Pseudomonas aeruginosa can inhibit the growth of cyanobacterium, Microcystis aeruginosa. In order to explore the inhibitory mechanism of P. aeruginosa on the cell growth and synthesis of intracellular substances of M. aeruginosa, concentrations of Chlorophyll-a, intracellular protein, carbohydrate, enzyme activities and ion metabolism of M. aeruginosa, were investigated. The results indicated that 83.84% algicidal efficiency of P. aeruginosa was achieved after treatment for 7 days. The strain inhibited the reproduction of M. aeruginosa by impeding the synthesis of intracellular protein and carbohydrate of cyanobacterium, and only a very small part of intracellular protein and carbohydrate was detected after exposure to P. aeruginosa for 5 days. P. aeruginosa caused the alteration of intracellular antioxidant enzyme activity of M. aeruginosa, such as catalase, peroxidase. The accumulation of malondialdehyde aggravated membrane injury after treatment for 3 days. P. aeruginosa also affected the ion metabolism of cyanobacteria. The release of Na(+) and Cl(-) was significantly enhanced while the uptake of K(+), Ca(2+), Mg(2+), NO3(-) and SO4(2)(-) decreased. Surface morphology and intracellular structure of cyanobacteria and bacterial cells changed dramatically over time as evidenced by electron microscope (SEM) and transmission electron microscope (TEM) analysis. These results revealed that the algicidal activity of P. aeruginosa was primarily due to the fermentation liquid of P. aeruginosa that impeded the synthesis of intracellular protein and carbohydrate, and damaged the cell membrane through membrane lipid peroxidation. PMID:26866757

  9. Different responses of pyoverdine genes to autoinduction in Pseudomonas aeruginosa and the group Pseudomonas fluorescens-Pseudomonas putida.

    PubMed

    Ambrosi, Cecilia; Leoni, Livia; Visca, Paolo

    2002-08-01

    We investigated the regulation of the psbA and pvdA pyoverdine biosynthesis genes, which encode the L-ornithine N(5)-oxygenase homologues in Pseudomonas strain B10 and Pseudomonas aeruginosa PAO1, respectively. We demonstrate that pyoverdine(B10), as the end product of its biosynthetic pathway, is a key participant of the control circuit regulating its own production in Pseudomonas strain B10. In P. aeruginosa PAO1, however, pyoverdine(PAO1) has no apparent role in the positive regulation of the pvdA gene. PMID:12147517

  10. Acquisition and role of molybdate in Pseudomonas aeruginosa.

    PubMed

    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.

  11. Electrochemically monitoring the antibiotic susceptibility of Pseudomonas aeruginosa biofilms.

    PubMed

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

    2015-11-01

    The condition of cells in Pseudomonas aeruginosa biofilms was monitored via the electrochemical detection of the electro-active virulence factor pyocyanin in a fabricated microfluidic growth chamber coupled with a disposable three electrode cell. Cells were exposed to 4, 16, and 100 mg L(-1) colistin sulfate after overnight growth. At the end of testing, the measured maximum peak current (and therefore pyocyanin concentration) was reduced by approximately 68% and 82% in P. aeruginosa exposed to 16 and 100 mg L(-1) colistin sulfate, respectively. Samples were removed from the microfluidic chamber, analyzed for viability using staining, and streaked onto culture plates to confirm that the P. aeruginosa cells were affected by the antibiotics. The correlation between electrical signal drop and the viability of P. aeruginosa cells after antibiotic exposure highlights the usefulness of this approach for future low cost antibiotic screening applications.

  12. Acquisition and Role of Molybdate in Pseudomonas aeruginosa

    PubMed Central

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

    2014-01-01

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

  13. Incidence and persistence of Pseudomonas aeruginosa in whirlpools.

    PubMed Central

    Price, D; Ahearn, D G

    1988-01-01

    Pseudomonas aeruginosa was isolated from seven commercial and two residential whirlpools that were treated with halogens. None of the commercial whirlpools was constantly maintained at appropriate disinfection levels. Superchlorination or the draining, cleaning, disinfection, and refilling of whirlpools markedly reduced densities of P. aeruginosa in whirlpool water, but the bacterial populations were rapidly reestablished (less than 10(3) cells per ml) when disinfectant concentrations decreased below recommended levels (chlorine, 3.0 ppm [3.0 micrograms/ml]; bromine, 6.0 ppm). P. aeruginosa in the water was replenished from various sources, such as hoses used to fill the whirlpool and the biofilm in the filter and piping of the whirlpool systems. Daily monitoring and adjustment of chemical characteristics (regardless of bather load) were essential for controlling densities of P. aeruginosa. Images PMID:3141463

  14. Purification and antibiofilm activity of AHL-lactonase from endophytic Enterobacter aerogenes VT66.

    PubMed

    Rajesh, P S; Rai, V Ravishankar

    2015-11-01

    The opportunistic pathogen Pseudomonas aeruginosa uses biofilm lifestyle to resist antibiotic treatment. In our study, endophytic bacterium Enterobacter aerogenes VT66 quenched the N-acyl homoserine lactone (AHL) molecules produced by P. aeruginosa PAO1. The quorum quenching activity was attributed to the presence of AHL-lactonase. The AHL-lactonase was purified using column chromatography and purified AHL-lactonase was applied for the control of biofilm formation in P. aeruginosa PAO1. The results showed that purified AHL-lactonase obtained with a molecular weight about 30kDa was able to inhibit more than 70% of biofilm in P. aeruginosa PAO1 (P<0.001). Antibiofilm activity of AHL-lactonase was correlated well with results from staining technique used to determine inhibition of biomass and viable cell activity. Therefore, results unambiguously confirm that the AHL-lactonase from E. aerogenes VT66 could be used as antibiofilm therapeutics in P. aeruginosa associated biomedical applications.

  15. Pseudomonas aeruginosa colonization in patients with spinal cord injuries.

    PubMed Central

    Gilmore, D S; Bruce, S K; Jimenez, E M; Schick, D G; Morrow, J W; Montgomerie, J Z

    1982-01-01

    The prevalence of Pseudomonas aeruginosa colonization of patients with spinal cord injury was studied annually from 1976 to 1980. The urethra, perineum, rectum, drainage bag, and urine of patients on the spinal cord injury service were cultured. A total of 224 men and 32 women were studied. Most patients were managed with an external urinary collection system or padding, with or without intermittent catheterization. P. aeruginosa was cultured from one or more body sites (urethra, perineum, or rectum) in 65% of men and 18% of women. Drainage bags on the beds were frequently colonized with P. aeruginosa (73%). Significant bacteriuria with P. aeruginosa was present in 19% of the men and 13% of the women. P. aeruginosa colonization of body sites in men was closely associated with the use of an external urinary collection system. Significantly greater urethral and perineal colonization was found in men using an external urinary collection system. P. aeruginosa serotype 11 was the predominant serotype for the first 3 years, and the number of patients colonized with serotype 11 increased with length of hospital stay. The prevalence of serotype 11 significantly decreased in the last 2 years. The antibiotic susceptibility of the strains of P. aeruginosa isolated from these patients did not change in the 5 years, except that there was increasing susceptibility to carbenicillin in later years. This increasing susceptibility to carbenicillin was a reflection of a decreased prevalence of serotype 11 in these patients, since serotype 11 was more resistant than other serotypes to carbenicillin. PMID:6818251

  16. Pseudomonas aeruginosa: assessment of risk from drinking water.

    PubMed

    Hardalo, C; Edberg, S C

    1997-01-01

    Pseudomonas aeruginosa is an ubiquitous environmental bacterium. It can be recovered, often in high numbers, in common food, especially vegetables. Moreover, it can be recovered in low numbers in drinking water. A small percentage of clones of P. aeruginosa possesses the required number of virulence factors to cause infection. However, P. aeruginosa will not proliferate on normal tissue but requires previously organs. Further narrowing the risk to human health is that only certain specific hosts are at risk, including patients with profound neutropenia, cystic fibrosis, severe burns, and those subject to foreign device installation. Other than these very well-defined groups, the general population is refractory to infection with P. aeruginosa. Because of its ubiquitous nature, it is not only not practical to eliminate P. aeruginosa from our food and drinking water, but attempts to do so would produce disinfection byproducts more hazardous than the species itself. Moreover, because there is no readily available sensitive and specific means to detect and identify P. aeruginosa available in the field, any potential regulation governing its control would not have a defined laboratory test measure of outcome. Accordingly, attempts to regulate P. aeruginosa in drinking water would not yield public health protection benefits and could, in fact, be counterproductive in this regard.

  17. Proteomic analysis of keratitis-associated Pseudomonas aeruginosa

    PubMed Central

    Sewell, Abby; Dunmire, Jeffrey; Wehmann, Michael; Rowe, Theresa

    2014-01-01

    Purpose To compare the proteomic profile of a clinical isolate of Pseudomonas aeruginosa (P. aeruginosa) obtained from an infected cornea of a contact lens wearer and the laboratory strain P. aeruginosa ATCC 10145. Methods Antibiotic sensitivity, motility, biofilm formation, and virulence tests were performed using standard methods. Whole protein lysates were analyzed with liquid chromatography/ tandem mass spectrometry (LC-MS/MS) in triplicate, and relative protein abundances were determined with spectral counting. The G test followed by a post hoc Holm-Sidak adjustment was used for the statistical analyses to determine significance in the differential expression of proteins between the two strains. Results A total of 687 proteins were detected. One-hundred thirty-three (133) proteins were significantly different between the two strains. Among these, 13 were upregulated, and 16 were downregulated in the clinical strain compared to ATCC 10145, whereas 57 were detected only in the clinical strain. The upregulated proteins are associated with virulence and pathogenicity. Conclusions Proteins detected at higher levels in the clinical strain of P. aeruginosa were proteins known to be virulence factors. These results confirm that the keratitis-associated P. aeruginosa strain is pathogenic and expresses a higher number of virulence factors compared to the laboratory strain ATCC 10145. Identification of the protein profile of the corneal strain of P. aeruginosa in this study will aid in elucidating novel intervention strategies for reducing the burden of P. aeruginosa infection in keratitis. PMID:25221424

  18. Crystal Structure of the Pseudomonas aeruginosa Virulence Factor Regulator

    SciTech Connect

    Cordes, Timothy J.; Worzalla, Gregory A.; Ginster, Aaron M.; Forest, Katrina T.

    2012-09-07

    Virulence factor regulator (Vfr) enhances Pseudomonas aeruginosa pathogenicity through its role as a global transcriptional regulator. The crystal structure of Vfr shows that it is a winged-helix DNA-binding protein like its homologue cyclic AMP receptor protein (CRP). In addition to an expected primary cyclic AMP-binding site, a second ligand-binding site is nestled between the N-terminal domain and the C-terminal helix-turn-helix domain. Unlike CRP, Vfr is a symmetric dimer in the absence of DNA. Removal of seven disordered N-terminal residues of Vfr prvents the growth of P. aeruginosa.

  19. Iron Depletion Enhances Production of Antimicrobials by Pseudomonas aeruginosa

    PubMed Central

    Nguyen, Angela T.; Jones, Jace W.; Ruge, Max A.; Kane, Maureen A.

    2015-01-01

    ABSTRACT Cystic fibrosis (CF) is a heritable disease characterized by chronic, polymicrobial lung infections. While Staphylococcus aureus is the dominant lung pathogen in young CF patients, Pseudomonas aeruginosa becomes predominant by adulthood. P. aeruginosa produces a variety of antimicrobials that likely contribute to this shift in microbial populations. In particular, secretion of 2-alkyl-4(1H)-quinolones (AQs) contributes to lysis of S. aureus in coculture, providing an iron source to P. aeruginosa both in vitro and in vivo. We previously showed that production of one such AQ, the Pseudomonas quinolone signal (PQS), is enhanced by iron depletion and that this induction is dependent upon the iron-responsive PrrF small RNAs (sRNAs). Here, we demonstrate that antimicrobial activity against S. aureus during coculture is also enhanced by iron depletion, and we provide evidence that multiple AQs contribute to this activity. Strikingly, a P. aeruginosa ΔprrF mutant, which produces very little PQS in monoculture, was capable of mediating iron-regulated growth suppression of S. aureus. We show that the presence of S. aureus suppresses the ΔprrF1,2 mutant's defect in iron-regulated PQS production, indicating that a PrrF-independent iron regulatory pathway mediates AQ production in coculture. We further demonstrate that iron-regulated antimicrobial production is conserved in multiple P. aeruginosa strains, including clinical isolates from CF patients. These results demonstrate that iron plays a central role in modulating interactions of P. aeruginosa with S. aureus. Moreover, our studies suggest that established iron regulatory pathways of these pathogens are significantly altered during polymicrobial infections. IMPORTANCE Chronic polymicrobial infections involving Pseudomonas aeruginosa and Staphylococcus aureus are a significant cause of morbidity and mortality, as the interplay between these two organisms exacerbates infection. This is in part due to enhanced

  20. Overproduction and assay of Pseudomonas aeruginosa phosphomannose isomerase.

    PubMed Central

    Gill, J F; Deretic, V; Chakrabarty, A M

    1986-01-01

    Phosphomannose isomerase activity was undetectable in extracts of mucoid (alginate-producing) Pseudomonas aeruginosa. When a P. aeruginosa gene previously shown to complement an alginate-negative mutant was overexpressed under the control of the tac promoter in the broad-host-range controlled-expression vector pMMB22, phosphomannose isomerase activity could be measured in extracts of P. aeruginosa and in a manA (phosphomannose isomerase-negative) mutant of Escherichia coli. P. aeruginosa extracts containing induced levels of enzyme were shown to interconvert fructose 6-phosphate and mannose 6-phosphate. A 56,000-dalton polypeptide was visualized on sodium dodecyl sulfate-polyacrylamide gels after induction in both hosts. When RNA-DNA dot- blot hybridization analysis was used, transcription of algA, the gene coding for P. aeruginosa phosphomannose isomerase, was not measurable from the chromosomes of either mucoid or nonmucoid P. aeruginosa. However, a high level of algA transcription was detected after expression of algA under tac promoter control in pMMB22. Images PMID:2426246

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

    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

  3. Tracking the immunopathological response to Pseudomonas aeruginosa during respiratory infections

    PubMed Central

    Cigana, Cristina; Lorè, Nicola Ivan; Riva, Camilla; De Fino, Ida; Spagnuolo, Lorenza; Sipione, Barbara; Rossi, Giacomo; Nonis, Alessandro; Cabrini, Giulio; Bragonzi, Alessandra

    2016-01-01

    Repeated cycles of infections, caused mainly by Pseudomonas aeruginosa, combined with a robust host immune response and tissue injury, determine the course and outcome of cystic fibrosis (CF) lung disease. As the disease progresses, P. aeruginosa adapts to the host modifying dramatically its phenotype; however, it remains unclear whether and how bacterial adaptive variants and their persistence influence the pathogenesis and disease development. Using in vitro and murine models of infection, we showed that P. aeruginosa CF-adaptive variants shaped the innate immune response favoring their persistence. Next, we refined a murine model of chronic pneumonia extending P. aeruginosa infection up to three months. In this model, including CFTR-deficient mice, we unveil that the P. aeruginosa persistence lead to CF hallmarks of airway remodelling and fibrosis, including epithelial hyperplasia and structure degeneration, goblet cell metaplasia, collagen deposition, elastin degradation and several additional markers of tissue damage. This murine model of P. aeruginosa chronic infection, reproducing CF lung pathology, will be instrumental to identify novel molecular targets and test newly tailored molecules inhibiting chronic inflammation and tissue damage processes in pre-clinical studies. PMID:26883959

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

    PubMed Central

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

    1993-01-01

    Interactions between bacterial biofilms formed by Pseudomonas aeruginosa and clarithromycin, a macrolide having no anti-P. aeruginosa activity, were investigated. P. aeruginosa incubated for 10 days on membrane filters formed biofilms on the surfaces of the filters. The biofilms were characterized by dense colonizations of bacteria and thick membranous structures that covered the colonies. Treatment of the biofilms with a relatively low concentration of clarithromycin for 5 days resulted in an eradication of the membranous structures. Quantitative analysis of alginate and hexose was done to evaluate the quantity of polysaccharides in or on the biofilms. Treatment of the biofilms with clarithromycin decreased the quantity of alginate and hexose and therefore perhaps the quantity of polysaccharides as well. Eradication of the membranous structures of biofilms, or the decrease in the quantity of polysaccharides, resulted in an increase in the rate of penetration of antibiotics through bacterial biofilms. In vivo therapeutic effects of ofloxacin in the rat infection model, in which the biofilm mode of growth of P. aeruginosa is characteristic, were enhanced by oral coadministration of clarithromycin. It is suggested that clarithromycin eradicated glycocalyx produced by P. aeruginosa, or suppressed the production of glycocalyx, by unknown mechanisms and thereby enhanced the therapeutic efficacies of other antimicrobial agents against infections caused by P. aeruginosa. Images PMID:8239580

  5. COMPARATIVE TAXONOMY OF CRYSTALLOGENIC STRAINS OF PSEUDOMONAS AERUGINOSA AND PSEUDOMONAS CHLORORAPHIS

    PubMed Central

    Haynes, William C.; Rhodes, Lenora J.

    1962-01-01

    Haynes, William C. (Northern Utilization Research and Development Division, Peoria, Ill.) and Lenora J. Rhodes. Comparative taxonomy of crystallogenic strains of Pseudomonas aeruginosa and Pseudomonas chlororaphis. J. Bacteriol. 84:1080–1084. 1962.—Only 11 of 39 strains received in the Agricultural Research Service Culture Collection under the designation Pseudonomas chlororaphis proved to be authentic; 28 were typical, pyocyanogenic strains of P. aeruginosa. The reason for this disproportionately high rate of misidentification apparently arises from an erroneous belief that the ability to produce green and yellow crystals of chlororaphin and oxychlororaphin is confined to P. chlororaphis. The ability of many strains of P. aeruginosa to do likewise is not well known. Inasmuch as the characteristic is not unique to P. chlororaphis, other criteria are required to distinguish crystallogenic strains of these species. After a taxonomic comparison of 18 strains of P. chlororaphis and 47 crystallogenic strains of P. aeruginosa, it was determined that there are three main distinctions: (i) P. aeruginosa grows well at 42 C but fails to grow upon serial transfer at 5 C, whereas P. chlororaphis fails to grow at 42 C, but grows well at 5 C: (ii) most strains of P. aeruginosa produce pyocyanin, whereas P. chlororaphis strains do not; (iii) P. aeruginosa cells possess only one or two polar flagella, whereas P. chlororaphis usually has at least four, sometimes as many as eight, polar flagella. PMID:13963593

  6. Membrane proteomes of Pseudomonas aeruginosa and Acinetobacter baumannii.

    PubMed

    Dé, E; Cosette, P; Coquet, L; Siroy, A; Alexandre, S; Duncan, A; Naudin, B; Rihouey, C; Schaumann, A; Junter, G A; Jouenne, T

    2011-12-01

    Acinetobacter baumannii and Pseudomonas aeruginosa are known for their intrinsic resistance to antibiotics. Between mechanisms involved in this resistance, diminished expression of outer membrane proteins and up-regulation of efflux pumps play an important role. The characterization of membrane proteins is consequently necessary because of their importance in the antibiotic resistance but also in virulence. This review presents proteomic investigations aiming to describe the protein content of the membranes of these two bacterial species. PMID:19942379

  7. Membrane proteomes of Pseudomonas aeruginosa and Acinetobacter baumannii.

    PubMed

    Dé, E; Cosette, P; Coquet, L; Siroy, A; Alexandre, S; Duncan, A; Naudin, B; Rihouey, C; Schaumann, A; Junter, G A; Jouenne, T

    2011-12-01

    Acinetobacter baumannii and Pseudomonas aeruginosa are known for their intrinsic resistance to antibiotics. Between mechanisms involved in this resistance, diminished expression of outer membrane proteins and up-regulation of efflux pumps play an important role. The characterization of membrane proteins is consequently necessary because of their importance in the antibiotic resistance but also in virulence. This review presents proteomic investigations aiming to describe the protein content of the membranes of these two bacterial species.

  8. Structure of type II dehydroquinase from Pseudomonas aeruginosa

    PubMed Central

    Reiling, Scott; Kelleher, Alan; Matsumoto, Monica M.; Robinson, Gonteria; Asojo, Oluwatoyin A.

    2014-01-01

    Pseudomonas aeruginosa causes opportunistic infections and is resistant to most antibiotics. Ongoing efforts to generate much-needed new antibiotics include targeting enzymes that are vital for P. aeruginosa but are absent in mammals. One such enzyme, type II dehydroquinase (DHQase), catalyzes the interconversion of 3-dehydroquinate and 3-dehydroshikimate, a necessary step in the shikimate pathway. This step is vital for the proper synthesis of phenylalanine, tryptophan, tyrosine and other aromatic metabolites. The recombinant expression, purification and crystal structure of catalytically active DHQase from P. aeruginosa (PaDHQase) are presented. Cubic crystals belonging to space group F23, with unit-cell parameters a = b = c = 125.39 Å, were obtained by vapor diffusion in sitting drops and the structure was refined to an R factor of 16% at 1.74 Å resolution. PaDHQase is a prototypical type II DHQase with the classical flavodoxin-like α/β topology. PMID:25372814

  9. Isolation of an iron-binding compound from Pseudomonas aeruginosa.

    PubMed Central

    Cox, C D; Graham, R

    1979-01-01

    An iron-binding compound was isolated from ethyl acetate extracts of culture supernatant fluids of Pseudomonas aeruginosa and was purified by successive paper and thin-layer chromatographic procedures. The purified compound was characterized by UV, visible, infrared, and fluorescence spectroscopy. The compound possesses phenolic characteristics, with little or no similarity to dihydroxybenzoates and no indication of a hydroxamate group. P. aeruginosa synthesized the compound during active growth in culture media containing less than 5 X 10(-6) M added FeCl3. When added to iron-poor cultures of P. aeruginosa, the compound promoted the growth of the bacterium and also reversed growth inhibition by the iron chelator ethylenediamine-di-(o-hydroxyphenylacetic acid). PMID:104968

  10. Haemolytic uraemic syndrome associated with Pseudomonas aeruginosa sepsis.

    PubMed

    Narayanan, Parameswaran; Rustagi, Rashi S; Sivaprakasam, Prabha; Subramanian, Mahadevan; Parameswaran, Sreejith; Mandal, Jharna; Kaplan, B S

    2013-11-01

    Haemolytic uraemic syndrome (HUS) is a recognized complication of infection with Shiga toxin-producing Escherichia coli (STEC) and Shigella dysenteriae type 1. Infections with other micro-organisms, especially Streptococcus pneumoniae, have been cited as causes of HUS. In addition, influenza virus and other viruses may rarely be associated with this syndrome. A 2-year-old girl presented with severe Pseudomonas aeruginosa sepsis with renal failure and ecthyma gangrenosum. Further investigations revealed features of HUS. She was managed with antibiotics and other supportive measures including peritoneal dialysis, and subsequently made a full recovery. A possible role of neuraminidase in the pathogenesis of P. aeruginosa-associated HUS was proposed. This is the first reported case of P. aeruginosa sepsis leading to HUS.

  11. Singly Flagellated Pseudomonas aeruginosa Chemotaxes Efficiently by Unbiased Motor Regulation

    PubMed Central

    Cai, Qiuxian; Li, Zhaojun; Ouyang, Qi

    2016-01-01

    ABSTRACT Pseudomonas aeruginosa is an opportunistic human pathogen that has long been known to chemotax. More recently, it has been established that chemotaxis is an important factor in the ability of P. aeruginosa to make biofilms. Genes that allow P. aeruginosa to chemotax are homologous with genes in the paradigmatic model organism for chemotaxis, Escherichia coli. However, P. aeruginosa is singly flagellated and E. coli has multiple flagella. Therefore, the regulation of counterclockwise/clockwise flagellar motor bias that allows E. coli to efficiently chemotax by runs and tumbles would lead to inefficient chemotaxis by P. aeruginosa, as half of a randomly oriented population would respond to a chemoattractant gradient in the wrong sense. How P. aeruginosa regulates flagellar rotation to achieve chemotaxis is not known. Here, we analyze the swimming trajectories of single cells in microfluidic channels and the rotations of cells tethered by their flagella to the surface of a variable-environment flow cell. We show that P. aeruginosa chemotaxes by symmetrically increasing the durations of both counterclockwise and clockwise flagellar rotations when swimming up the chemoattractant gradient and symmetrically decreasing rotation durations when swimming down the chemoattractant gradient. Unlike the case for E. coli, the counterclockwise/clockwise bias stays constant for P. aeruginosa. We describe P. aeruginosa’s chemotaxis using an analytical model for symmetric motor regulation. We use this model to do simulations that show that, given P. aeruginosa’s physiological constraints on motility, its distinct, symmetric regulation of motor switching optimizes chemotaxis. PMID:27048795

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-07-18

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

  14. MexXY multidrug efflux system of Pseudomonas aeruginosa

    PubMed Central

    Morita, Yuji; Tomida, Junko; Kawamura, Yoshiaki

    2012-01-01

    Anti-pseudomonas aminoglycosides, such as amikacin and tobramycin, are used in the treatment of Pseudomonas aeruginosa infections. However, their use is linked to the development of resistance. During the last decade, the MexXY multidrug efflux system has been comprehensively studied, and numerous reports of laboratory and clinical isolates have been published. This system has been increasingly recognized as one of the primary determinants of aminoglycoside resistance in P. aeruginosa. In P. aeruginosa cystic fibrosis isolates, upregulation of the pump is considered the most common mechanism of aminoglycoside resistance. Non-fermentative Gram-negative pathogens possessing very close MexXY orthologs such as Achromobacter xylosoxidans and various Burkholderia species (e.g., Burkholderia pseudomallei and B. cepacia complexes), but not B. gladioli, are intrinsically resistant to aminoglycosides. Here, we summarize the properties (e.g., discovery, mechanism, gene expression, clinical significance) of the P. aeruginosa MexXY pump and other aminoglycoside efflux pumps such as AcrD of Escherichia coli, AmrAB-OprA of B. pseudomallei, and AdeABC of Acinetobacter baumannii. MexXY inducibility of the PA5471 gene product, which is dependent on ribosome inhibition or oxidative stress, is noteworthy. Moreover, the discovery of the cognate outer membrane component (OprA) of MexXY in the multidrug-resistant clinical isolate PA7, serotype O12 deserves special attention. PMID:23233851

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

    PubMed

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

    2016-08-01

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

  16. Proteinases of Pseudomonas aeruginosa evoke mucin release by tracheal epithelium.

    PubMed Central

    Klinger, J D; Tandler, B; Liedtke, C M; Boat, T F

    1984-01-01

    We have determined the potential of exoproducts from pathogenic bacteria to stimulate the release of high molecular weight mucins from goblet cells of airway epithelium in a rabbit tracheal explant system. Culture supernatants from proteolytic strains of Pseudomonas aeruginosa and Serratia marcescens, but not supernatants from a number of non-proteolytic strains, released mucins from goblet cells. Highly purified elastase and alkaline proteinase from P. aeruginosa stimulated goblet cell mucin release in a dose-dependent fashion. Lipopolysaccharide, exotoxin A, and alginate of P. aeruginosa did not possess mucin release properties. Proteolytic activity was required for mucin release by P. aeruginosa elastase, but such release in goblet cells was not mediated by cyclic AMP. Morphologic studies suggested rapid release of mucins from goblet cells was response to elastase by a process resembling apocrine secretion. Several nonbacterial proteinases mimicked the effect of Pseudomonas proteases. These studies provide support for the hypothesis that bacterial and other play a role in the pathogenesis of mucus hypersecretion in acute and chronic lung infections. Images PMID:6568227

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

    SciTech Connect

    Saiman, L.; Cacalano, G.; Prince, A. )

    1990-08-01

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

  18. Genetic and Functional Diversity of Pseudomonas aeruginosa Lipopolysaccharide

    PubMed Central

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

    2011-01-01

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

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

    PubMed

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

    2016-05-01

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

  20. A Network Biology Approach to Denitrification in Pseudomonas aeruginosa

    PubMed Central

    Arat, Seda; Bullerjahn, George S.; Laubenbacher, Reinhard

    2015-01-01

    Pseudomonas aeruginosa is a metabolically flexible member of the Gammaproteobacteria. Under anaerobic conditions and the presence of nitrate, P. aeruginosa can perform (complete) denitrification, a respiratory process of dissimilatory nitrate reduction to nitrogen gas via nitrite (NO2), nitric oxide (NO) and nitrous oxide (N2O). This study focuses on understanding the influence of environmental conditions on bacterial denitrification performance, using a mathematical model of a metabolic network in P. aeruginosa. To our knowledge, this is the first mathematical model of denitrification for this bacterium. Analysis of the long-term behavior of the network under changing concentration levels of oxygen (O2), nitrate (NO3), and phosphate (PO4) suggests that PO4 concentration strongly affects denitrification performance. The model provides three predictions on denitrification activity of P. aeruginosa under various environmental conditions, and these predictions are either experimentally validated or supported by pertinent biological literature. One motivation for this study is to capture the effect of PO4 on a denitrification metabolic network of P. aeruginosa in order to shed light on mechanisms for greenhouse gas N2O accumulation during seasonal oxygen depletion in aquatic environments such as Lake Erie (Laurentian Great Lakes, USA). Simulating the microbial production of greenhouse gases in anaerobic aquatic systems such as Lake Erie allows a deeper understanding of the contributing environmental effects that will inform studies on, and remediation strategies for, other hypoxic sites worldwide. PMID:25706405

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

    PubMed Central

    2013-01-01

    Background The elucidation of the routes of transmission of a pathogen is crucial for the prevention of infectious diseases caused by bacteria that are not a resident in human tissue. The purpose of this report is to describe a case of suture-related conjunctivitis caused by Pseudomonas aeruginosa for which we identified the transmission route using pulsed-field gel electrophoresis (PFGE). Case presentation A 38-year-old man, who had undergone surgery for glaucoma 2 years ago previously, presented with redness, discomfort, and mucopurulent discharge in the right eye. A 9–0 silk suture had been left on the conjunctiva. A strain of P. aeruginosa was isolated from a culture obtained from the suture, and the patient was therefore diagnosed with suture-related conjunctivitis caused by P. aeruginosa. The conjunctivitis was cured by the application of an antimicrobial ophthalmic solution and removal of the suture. We used PFGE to survey of the indoor and outdoor environments around the patient’s house and office in order to elucidate the route of transmission of the infection. Three strains of P. aeruginosa were isolated from the patient’s indoor environment, and the isolate obtained from the patient’s bathroom was identical to that from the suture. Conclusion The case highlights the fact that an indoor environmental strain of P. aeruginosa can cause ocular infections. PMID:23815865

  2. Three Pseudomonas aeruginosa strains with different protease profiles.

    PubMed

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

    2013-01-01

    The proteolytic activity of three Pseudomonas aeruginosa strains, ATCC 27853 - a reference strain, and two clinical isolates was tested. The activity was examined after culturing the bacteria in two different growth media: the minimal M9 medium and rich Luria-Bertani broth (LB). Based on zymograms and protease activity specific assays, it was concluded that the reference strain produced three proteolytic enzymes in the LB medium: protease IV, elastase B and elastase A, while alkaline protease was only produced in the M9 medium. The clinical isolates of P. aeruginosa produced elastase B and alkaline protease when grown in the LB medium and the minimal M9 medium, respectively. PCR analysis confirmed the presence of both the lasB gene encoding elastase B and aprA coding for alkaline protease in the genomes of the three P. aeruginosa strains analyzed. The expression of these genes coding for two important P. aeruginosa virulence factors was dependent on the growth conditions in all the strains studied. The contribution of the extracellular proteinases to the virulence of P. aeruginosa strains used in this study was investigated using an insect model, the greater wax moth Galleria mellonella.

  3. Pseudomonas aeruginosa Virulence and Therapy: Evolving Translational Strategies

    PubMed Central

    Veesenmeyer, Jeffrey L.; Lisboa, Thiago; Rello, Jordi

    2009-01-01

    Structured abstract Objective Although most reviews of Pseudomonas aeruginosa therapeutics focus on antibiotics currently in use or in the pipeline, we review evolving translational strategies aimed at using virulence factor antagonists as adjuvant therapies. Data Source Current literature regarding P. aeruginosa virulence determinants and approaches that target them, with an emphasis on type III secretion, quorum-sensing, biofilms, and flagella. Data Extraction and Synthesis P. aeruginosa remains one of the most important pathogens in nosocomial infections, with high associated morbidity and mortality. Its predilection to develop resistance to antibiotics and expression of multiple virulence factors contributes to the frequent ineffectiveness of current therapies. Among the many P. aeruginosa virulence determinants that impact infections, type III secretion, quorum sensing, biofilm formation, and flagella have been the focus of much recent investigation. Here we review how increased understanding of these important bacterial structures and processes has enabled the development of novel approaches to inhibit each. These promising translational strategies may lead to the development of adjuvant therapies capable of improving outcomes. Conclusions Adjuvant therapies directed against virulence factors have the potential to improve outcomes in P. aeruginosa infections. PMID:19325463

  4. [Resistance to antibiotics in Pseudomonas aeruginosa in Colombian hospitals].

    PubMed

    Villa, Lina M; Cortés, Jorge A; Leal, Aura L; Meneses, Andrés; Meléndez, Martha P

    2013-12-01

    Pseudomonas aeruginosa infections cause high morbidity and mortality. We performed a descriptive analysis of the rates of antibiotic resistance in isolates of P. aeruginosa in 33 hospitals enrolled in a surveillance network in Colombia. The study was conducted between January 2005 and December 2009 .9905 isolates of P. aeruginosa were identified, (4.9% of all strains). In intensive care units (ICU) P. aeruginosa showed an overall resistance to aztreonam, cefepime , ceftazidime, imipenem, meropenem , and piperacillin / tazobactam of 31.8% , 23.9% , 24.8%, 22.5%, 20.3% and 22.3%, respectively. Resistance rates increased for piperacillin/tazobactam, cefepime, and imipenem; remained unchanged for meropenem; and decreased for aminoglycosides, quinolones and ceftazidime. Resistance to one, two and three or more families of antibiotics was found in 17%, 12.5%, and 32.1%, respectively. In samples collected from the wards, the resistance rate was lower but usually over 10%. Antibiotic resistance in P. aeruginosa isolates in hospitalized patients and particularly in those admitted to ICUs in Colombia is high.

  5. The Genomic Basis of Evolutionary Innovation in Pseudomonas aeruginosa

    PubMed Central

    Wagner, Andreas; MacLean, R. Craig

    2016-01-01

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

  6. A network biology approach to denitrification in Pseudomonas aeruginosa

    DOE PAGES

    Arat, Seda; Bullerjahn, George S.; Laubenbacher, Reinhard

    2015-02-23

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

  7. Why Does the Healthy Cornea Resist Pseudomonas aeruginosa Infection?

    PubMed Central

    Evans, David J.; Fleiszig, Suzanne M. J.

    2013-01-01

    Purpose To provide our perspective on why the cornea is resistant to infection based on our research results with Pseudomonas aeruginosa. Perspective We focus on our current understanding of the interplay between bacteria, tear fluid and the corneal epithelium that determine health as the usual outcome, and propose a theoretical model for how contact lens wear might change those interactions to enable susceptibility to P. aeruginosa infection. Methods Use of “null-infection” in vivo models, cultured human corneal epithelial cells, contact lens-wearing animal models, and bacterial genetics help to elucidate mechanisms by which P. aeruginosa survive at the ocular surface, adheres, and traverses multilayered corneal epithelia. These models also help elucidate the molecular mechanisms of corneal epithelial innate defense. Results and Discussion Tear fluid and the corneal epithelium combine to make a formidable defense against P. aeruginosa infection of the cornea. Part of that defense involves the expression of antimicrobials such as β-defensins, the cathelicidin LL-37, cytokeratin-derived antimicrobial peptides, and RNase7. Immunomodulators such as SP-D and ST2 also contribute. Innate defenses of the cornea depend in part on MyD88, a key adaptor protein of TLR and IL-1R signaling, but the basal lamina represents the final barrier to bacterial penetration. Overcoming these defenses involves P. aeruginosa adaptation, expression of the type three secretion system, proteases, and P. aeruginosa biofilm formation on contact lenses. Conclusion After more than two decades of research focused on understanding how contact lens wear predisposes to P. aeruginosa infection, our working hypothesis places blame for microbial keratitis on bacterial adaptation to ocular surface defenses, combined with changes to the biochemistry of the corneal surface caused by trapping bacteria and tear fluid against the cornea under the lens. PMID:23601656

  8. Enzyme-linked immunosorbent assay for detection of antibodies to Pseudomonas aeruginosa exoproteins.

    PubMed

    Granström, M; Wretlind, B; Markman, B; Pavlovskis, O R; Vasil, M L

    1985-04-01

    Enzyme-linked immunosorbent assays were developed with four purified Pseudomonas aeruginosa extracellular proteins (exotoxin A, elastase, alkaline protease, and phospholipase C) to determine antibody levels in sera from healthy subjects and the serological response in patients colonized or infected with Pseudomonas aeruginosa. Five of 39 burn patients with wounds colonized by Pseudomonas aeruginosa had elevated antibody titers to alkaline protease. Response to the other antigens was found in only a few patients. Pseudomonas aeruginosa infections (septicemia, osteitis, pneumonia etc.) resulted in increased antibody levels to exotoxin A or phospholipase C in 15 of 22 patients. These findings suggest that repeated determinations of antibodies to Pseudomonas aeruginosa exotoxin A and phospholipase C might be used to monitor therapy in certain patients with osteitis and other deep Pseudomonas infections.

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

    PubMed

    Abbas, Hisham A

    2015-01-01

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

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

    PubMed

    Abbas, Hisham A

    2015-01-01

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

  11. Adherence of Pseudomonas aeruginosa to contact lenses

    SciTech Connect

    Miller, M.J.

    1988-01-01

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

  12. Inhibition of Pseudomonas aeruginosa biofilm formation on wound dressings

    PubMed Central

    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.

    2016-01-01

    Chronic non-healing 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 upon prior reports, we examined whether the amino acid tryptophan would inhibit P. aeruginosa biofilm formation on the 3-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. PMID:26342168

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

    PubMed

    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.

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

    PubMed

    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. PMID:26342168

  15. Pseudomonas aeruginosa PAO1 Kills Caenorhabditis elegans by Cyanide Poisoning

    PubMed Central

    Gallagher, Larry A.; Manoil, Colin

    2001-01-01

    In this report we describe experiments to investigate a simple virulence model in which Pseudomonas aeruginosa PAO1 rapidly paralyzes and kills the nematode Caenorhabditis elegans. Our results imply that hydrogen cyanide is the sole or primary toxic factor produced by P. aeruginosa that is responsible for killing of the nematode. Four lines of evidence support this conclusion. First, a transposon insertion mutation in a gene encoding a subunit of hydrogen cyanide synthase (hcnC) eliminated nematode killing. Second, the 17 avirulent mutants examined all exhibited reduced cyanide synthesis, and the residual production levels correlated with killing efficiency. Third, exposure to exogenous cyanide alone at levels comparable to the level produced by PAO1 killed nematodes with kinetics similar to those observed with bacteria. The killing was not enhanced if hcnC mutant bacteria were present during cyanide exposure. And fourth, a nematode mutant (egl-9) resistant to P. aeruginosa was also resistant to killing by exogenous cyanide in the absence of bacteria. A model for nematode killing based on inhibition of mitochondrial cytochrome oxidase is presented. The action of cyanide helps account for the unusually broad host range of virulence of P. aeruginosa and may contribute to the pathogenesis in opportunistic human infections due to the bacterium. PMID:11591663

  16. [Sodium houttuyfonate inhibits virulence related motility of Pseudomonas aeruginosa].

    PubMed

    Wu, Da-qiang; Huang, Wei-feng; Duan, Qiang-jun; Cheng, Hui-juan; Wang, Chang-zhong

    2015-04-01

    Sodium houttuyfonate (SH) is a derivative of effective component of a Chinese material medica, Houttuynia cordata, which is applied in anti-infection of microorganism. But, the antimicrobial mechanisms of SH still remain unclear. Here, we firstly discovered that SH effectively inhibits the three types of virulence related motility of.Pseudomonas aeruginosa, i.e., swimming, twitching and swarming. The plate assay results showed that the inhibitory action of SH against swimming and twitching in 24 h and swarming in 48 h is dose-dependent; and bacteria nearly lost all of the motile activities under the concentration of 1 x minimum inhibitory concentration (MIC) (512 mg x L(-1) same as azithromycin positive group (1 x MIC, 16 mg x L(-1)). Furthermore, we found that the expression of structural gene flgB and pilG is down-regulated by SH, which implies that inhibitory mechanism of SH against motility of P. aeruginosa may be due to the inhibition of flagella and pili bioformation of P. aeruginosa by SR Therefore, our presented results firstly demonstrate that SH effectively inhibits the motility activities of P. aeruginosa, and suggest that SH could be a promising antipseudomonas agents in clinic. PMID:26281603

  17. Adaptation of Aerobically Growing Pseudomonas aeruginosa to Copper Starvation▿ †

    PubMed Central

    Frangipani, Emanuela; Slaveykova, Vera I.; Reimmann, Cornelia; Haas, Dieter

    2008-01-01

    Restricted bioavailability of copper in certain environments can interfere with cellular respiration because copper is an essential cofactor of most terminal oxidases. The global response of the metabolically versatile bacterium and opportunistic pathogen Pseudomonas aeruginosa to copper limitation was assessed under aerobic conditions. Expression of cioAB (encoding an alternative, copper-independent, cyanide-resistant ubiquinol oxidase) was upregulated, whereas numerous iron uptake functions (including the siderophores pyoverdine and pyochelin) were expressed at reduced levels, presumably reflecting a lower demand for iron by respiratory enzymes. Wild-type P. aeruginosa was able to grow aerobically in a defined glucose medium depleted of copper, whereas a cioAB mutant did not grow. Thus, P. aeruginosa relies on the CioAB enzyme to cope with severe copper deprivation. A quadruple cyo cco1 cco2 cox mutant, which was deleted for all known heme-copper terminal oxidases of P. aeruginosa, grew aerobically, albeit more slowly than did the wild type, indicating that the CioAB enzyme is capable of energy conservation. However, the expression of a cioA′-′lacZ fusion was less dependent on the copper status in the quadruple mutant than in the wild type, suggesting that copper availability might affect cioAB expression indirectly, via the function of the heme-copper oxidases. PMID:18708503

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

    PubMed Central

    Peek, Mary E.; Bhatnagar, Abhinav; McCarty, Nael A.; Zughaier, Susu M.

    2012-01-01

    Pseudomonas aeruginosa is the most common pathogen that persists in the cystic fibrosis lungs. Bacteria such as P. aeruginosa secrete siderophores (iron-chelating molecules) and the host limits bacterial growth by producing neutrophil-gelatinase-associated lipocalin (NGAL) that specifically scavenges bacterial siderophores, therefore preventing bacteria from establishing infection. P. aeruginosa produces a major siderophore known as pyoverdine, found to be important for bacterial virulence and biofilm development. We report that pyoverdine did not bind to NGAL, as measured by tryptophan fluorescence quenching, while enterobactin bound to NGAL effectively causing a strong response. The experimental data indicate that pyoverdine evades NGAL recognition. We then employed a molecular modeling approach to simulate the binding of pyoverdine to human NGAL using NGAL's published crystal structures. The docking of pyoverdine to NGAL predicted nine different docking positions; however, neither apo- nor ferric forms of pyoverdine docked into the ligand-binding site in the calyx of NGAL where siderophores are known to bind. The molecular modeling results offer structural support that pyoverdine does not bind to NGAL, confirming the results obtained in the tryptophan quenching assay. The data suggest that pyoverdine is a stealth siderophore that evades NGAL recognition allowing P. aeruginosa to establish chronic infections in CF lungs. PMID:22973307

  19. The heme oxygenase(s)-phytochrome system of Pseudomonas aeruginosa.

    PubMed

    Wegele, Rosalina; Tasler, Ronja; Zeng, Yuhong; Rivera, Mario; Frankenberg-Dinkel, Nicole

    2004-10-29

    For many pathogenic bacteria like Pseudomonas aeruginosa heme is an essential source of iron. After uptake, the heme molecule is degraded by heme oxygenases to yield iron, carbon monoxide, and biliverdin. The heme oxygenase PigA is only induced under iron-limiting conditions and produces the unusual biliverdin isomers IXbeta and IXdelta. The gene for a second putative heme oxygenase in P. aeruginosa, bphO, occurs in an operon with the gene bphP encoding a bacterial phytochrome. Here we provide biochemical evidence that bphO encodes for a second heme oxygenase in P. aeruginosa. HPLC, (1)H, and (13)C NMR studies indicate that BphO is a "classic" heme oxygenase in that it produces biliverdin IXalpha. The data also suggest that the overall fold of BphO is likely to be the same as that reported for other alpha-hydroxylating heme oxygenases. Recombinant BphO was shown to prefer ferredoxins or ascorbate as a source of reducing equivalents in vitro and the rate-limiting step for the oxidation of heme to biliverdin is the release of product. In eukaryotes, the release of biliverdin is driven by biliverdin reductase, the subsequent enzyme in heme catabolism. Because P. aeruginosa lacks a biliverdin reductase homologue, data are presented indicating an involvement of the bacterial phytochrome BphP in biliverdin release from BphO and possibly from PigA.

  20. 7-fluoroindole as an antivirulence compound against Pseudomonas aeruginosa.

    PubMed

    Lee, Jin-Hyung; Kim, Yong-Guy; Cho, Moo Hwan; Kim, Jung-Ae; Lee, Jintae

    2012-04-01

    The emergence of antibiotic resistance has necessitated new therapeutic approaches for combating persistent bacterial infection. An alternative approach is regulation of bacterial virulence instead of growth suppression, which can readily lead to drug resistance. The virulence of the opportunistic human pathogen Pseudomonas aeruginosa depends on a large number of extracellular factors and biofilm formation. Thirty-one natural and synthetic indole derivatives were screened. 7-fluoroindole (7FI) was identified as a compound that inhibits biofilm formation and blood hemolysis without inhibiting the growth of planktonic P. aeruginosa cells. Moreover, 7FI markedly reduced the production of quorum-sensing (QS)-regulated virulence factors 2-heptyl-3-hydroxy-4(1H)-quinolone, pyocyanin, rhamnolipid, two siderophores, pyoverdine and pyochelin. 7FI clearly suppressed swarming motility, protease activity and the production of a polymeric matrix in P. aeruginosa. However, unlike natural indole compounds, synthetic 7FI did not increase antibiotic resistance. Therefore, 7FI is a potential candidate for use in an antivirulence approach against persistent P. aeruginosa infection. PMID:22251040

  1. Adaptation of aerobically growing Pseudomonas aeruginosa to copper starvation.

    PubMed

    Frangipani, Emanuela; Slaveykova, Vera I; Reimmann, Cornelia; Haas, Dieter

    2008-10-01

    Restricted bioavailability of copper in certain environments can interfere with cellular respiration because copper is an essential cofactor of most terminal oxidases. The global response of the metabolically versatile bacterium and opportunistic pathogen Pseudomonas aeruginosa to copper limitation was assessed under aerobic conditions. Expression of cioAB (encoding an alternative, copper-independent, cyanide-resistant ubiquinol oxidase) was upregulated, whereas numerous iron uptake functions (including the siderophores pyoverdine and pyochelin) were expressed at reduced levels, presumably reflecting a lower demand for iron by respiratory enzymes. Wild-type P. aeruginosa was able to grow aerobically in a defined glucose medium depleted of copper, whereas a cioAB mutant did not grow. Thus, P. aeruginosa relies on the CioAB enzyme to cope with severe copper deprivation. A quadruple cyo cco1 cco2 cox mutant, which was deleted for all known heme-copper terminal oxidases of P. aeruginosa, grew aerobically, albeit more slowly than did the wild type, indicating that the CioAB enzyme is capable of energy conservation. However, the expression of a cioA'-'lacZ fusion was less dependent on the copper status in the quadruple mutant than in the wild type, suggesting that copper availability might affect cioAB expression indirectly, via the function of the heme-copper oxidases. PMID:18708503

  2. Chlorinated phenol-induced physiological antibiotic resistance in Pseudomonas aeruginosa.

    PubMed

    Muller, Jocelyn Fraga; Ghosh, Sudeshna; Ikuma, Kaoru; Stevens, Ann M; Love, Nancy G

    2015-11-01

    Pseudomonas aeruginosa is a ubiquitous environmental bacterium and an opportunistic pathogen with the ability to rapidly develop multidrug resistance under selective pressure. Previous work demonstrated that upon exposure to the environmental contaminant pentachlorophenol (PCP), P. aeruginosa PAO1 increases expression of multiple multidrug efflux pumps, including the MexAB-OprM pump. The current study describes increases in the antibiotic resistance of PAO1 upon exposure to PCP and other chlorinated organics, including triclosan. Only exposure to chlorinated phenols induced the mexAB-oprM-mediated antibiotic-resistant phenotype. Thus, chlorinated phenols have the potential to contribute to transient phenotypic increases of antibiotic resistance that are relevant when both compounds are present in the environment.

  3. Flagellation of Pseudomonas aeruginosa in newly divided cells

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  4. [Profiles of resistance to aminosides of Pseudomonas aeruginosa].

    PubMed

    Lesage, D; Delisle-Mizon, F; Vergez, P; Daguet, G

    1987-05-01

    Among all Gram-negative bacilli, Pseudomonas aeruginosa is one of the most resistant to aminoglycosides. Five hundred and seventeen P. aeruginosa strains were studied. Isolates came from three Paris hospitals. Reference strains were provided by P. Courvalin and A. Philippon. The following aminoglycosides were used: streptomycin (S), spectinomycin (Sp), kanamycin (K), neomycin (N), gentamicin (G), sisomicin (Ss), netilmicin (Nt), tobramycin (T), amikacin (A), habekacin (H). The in vitro activity of antibiotics was evaluated by the standardized disk agar diffusion test. Distribution of inhibition zone diameters among susceptible strains were represented by histograms. Resistance frequency to aminoglycosides was: G: 61.5%, Ss: 38.1%, T: 35.8%, Nt: 58.2%, A: 15.5%, Seven resistance patterns were identified: G: 3%, G Ss: 3%, G Nt: 8%, G Ss Nt: 7%, G Ss T: 5%, G Ss T Nt: 53%, G Ss T Nt A: 21%. Hypothesis about resistance mechanisms and interpretation of disk agar diffusion test are discussed.

  5. Mass Spectrometry Analysis of Pseudomonas aeruginosa Treated With Azithromycin

    PubMed Central

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

    2015-01-01

    In microbiology, changes in specialized metabolite production (cell-to-cell signaling metabolites, virulence factors and natural products) are measured using phenotypic assays. However, advances in mass spectrometry based techniques including imaging mass spectrometry (IMS) now allow researchers to directly visualize the production of specialized metabolites from microbial colony biofilms. In this study, a combination of IMS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to visualize the effect of the macrolide antibiotic azithromycin (AZM) on colony biofilms of Pseudomonas aeruginosa. While previous research suggested that AZM may inhibit cell-to-cell signaling of P. aeruginosa and thereby reducing pathogenicity, we observed no clear decrease in specialized metabolite production. PMID:25801585

  6. [Water used for hemodialysis equipment: where is Pseudomonas aeruginosa?].

    PubMed

    Ducki, Sébastien; Francini, Nicolas; Blech, Marie-Françoise

    2005-05-01

    The water used in dilution of the dialysis solutions constitutes an essential element of the efficiency and the safety of this therapeutics. Water must be specifically treated, and some technical rules must be respected, such as disinfection of the equipment for water treatment, to guarantee a satisfying level for whole the installation. This article reports the investigations, which were led to find the spring of Pseudomonas aeruginosa which contamined in a recurring way the water feeding dialysis equipment. The observation of samples'chronology and an analysis of the sanitary pad suggested a contamination during disinfection. Sample of residual water from the pump used for the injection of Dialox identified this reservoir as origin of the contamination. To stop this contamination by P. aeruginosa, a pump maintenance revision and purges of the system were used.

  7. Mass Spectrometry Analysis of Pseudomonas aeruginosa Treated with Azithromycin

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  8. Regulation of the Mandelate Pathway in Pseudomonas aeruginosa

    PubMed Central

    Rosenberg, S. L.

    1971-01-01

    The pathway of mandelate metabolism in Pseudomonas aeruginosa is composed of the following steps: l(+)-mandelate → benzoylformate → benzaldehyde → benzoate. These three steps are unique to mandelate oxidation; the benzoate formed is further metabolized via the β-ketoadipate pathway. The first enzyme, l(+)-mandelate dehydrogenase, is induced by its substrate. The second and third enzymes, benzoylformate decarboxylase and benzaldehyde dehydrogenase, are both induced by benzoylformate. The same benzaldehyde dehydrogenase, or one very similar to it, is also induced by β-ketoadipate, an intermediate in the subsequent metabolism of benzoate. This dehydrogenase may also be induced by adipate or a metabolite of adipate. These conclusions have been drawn from the physiological and genetic properties of wild-type P. aeruginosa strains and from the study of mutants lacking the second and third enzyme activities. PMID:5003176

  9. [Use od ozone for disinfection of ships' system of water supply contaminated by Pseudomonas aeruginosa].

    PubMed

    Rakhmanin, Iu A; Strikalenko, T V; Mokienko, A V; Stoianova, N V; Gutsel', Iu I

    1990-11-01

    Experimental substantiation is given of the use of ozone in doses, recommended for disinfection of water and ship water supply systems infected by Pseudomonas aeruginosa. The positive effect of ozonation of water supply systems infected by Pseudomonas aeruginosa was confirmed by results of field testing on ships of the Black sea marine steam-navigation.

  10. The Approach to Pseudomonas aeruginosa in Cystic Fibrosis.

    PubMed

    Talwalkar, Jaideep S; Murray, Thomas S

    2016-03-01

    There is a high prevalence of Pseudomonas aeruginosa in patients with cystic fibrosis and clear epidemiologic links between chronic infection and morbidity and mortality exist. Prevention and early identification of infection are critical, and stand to improve with the advent of new vaccines and laboratory methods. Once the organism is identified, a variety of treatment options are available. Aggressive use of antipseudomonal antibiotics is the standard of care for acute pulmonary exacerbations in cystic fibrosis, and providers must take into account specific patient characteristics when making treatment decisions related to antibiotic selection, route and duration of administration, and site of care.

  11. Antibiotic susceptibility of clinical isolates of Pseudomonas aeruginosa.

    PubMed

    Cervantes-Vega, C; Chavez, J; Rodriguez, M G

    1986-01-01

    Three hundred and twenty two clinical isolates of Pseudomonas aeruginosa collected in Morelia, México, were analyzed for in vitro susceptibility to five antibiotics by agar dilution tests. Antibiotic resistance was shown by 50% of total isolates. Frequencies of resistance were: streptomycin, 47%; gentamicin, 13%; tobramycin, 8%; and carbenicillin, 7%; no amikacin resistance was found. The more common resistance patterns were streptomycin, gentamicin-streptomycin, and tobramycin-gentamicin-streptomycin. Resistance to either tobramycin, gentamicin or carbenicillin was found mainly in pyocin type 10 isolates. The proportion of antibiotic resistant isolates ranged from 37 to 75% in four hospitals, and amounted 24% in three clinical laboratories.

  12. Mitogenic effects of purified outer membrane proteins from Pseudomonas aeruginosa.

    PubMed Central

    Chen, Y H; Hancock, R E; Mishell, R I

    1980-01-01

    Three major outer membrane proteins from Pseudomonas aeruginosa PAO1 were purified and tested for their ability to stimulate resting murine lymphocytes to proliferate. It was demonstrated that picomole amounts of all three proteins were mitogenic for both intact and T-lymphocyte-depleted populations of spleen cells from C3H/HeJ mice. In contrast, they had no activity against either mature or immature thymocytes. Since the strain of mice used is unable to respond to lipopolysaccharide, we condlude that the three proteins are B-cell mitogens. Images Fig. 2 PMID:6769818

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  14. Infections with Pseudomonas aeruginosa in patients with cystic fibrosis.

    PubMed

    Tümmler, B; Bosshammer, J; Breitenstein, S; Brockhausen, I; Gudowius, P; Herrmann, C; Herrmann, S; Heuer, T; Kubesch, P; Mekus, F; Römling, U; Schmidt, K D; Spangenberg, C; Walter, S

    1997-02-01

    The lung infection with Pseudomonas aeruginosa is regarded as one of the major causes of health decline in patients with cystic fibrosis (CF). The CF host response to the persistent bacterial antigen load in the endobronchiolar lumen is characterized by a pronounced humoral response, local production of cytokines, influx of neutrophils into the lung and a protease-protease inhibitor imbalance predominantly sustained by released neutrophil elastase. CF is an autosomal recessive disease, and we could demonstrate for our local patient population that the age-dependent risk to become chronically colonized with P. aeruginosa can be differentiated by the disease-causing CFTR mutation genotype. The age-specific colonisation rates were significantly lower in pancreas sufficient than in pancreas insufficient patients. P. aeruginosa is occasionally detected in throat swabs already in infancy or early childhood in most patients although there is a lapse of several years amenable to preventive measures such as vaccination until onset of persistent colonization. The epidemiology of the infection with P. aeruginosa was investigated by quantitative macrorestriction fragment pattern analysis. The distribution and frequency of clones found in CF patients match that found in other clinical and environmental aquatic habitats, but the over-representation of specific clones at a CF clinic indicates a significant impact of nosocomial transmission for the prevalence of P. aeruginosa-positive patients at a particular center. Most patients remain colonized with the initially acquired P. aeruginosa clone. According to direct sputum analysis the majority of patients is carrying a single clonal variant at a concentration of 10(7)-10(9) CFU. Co-colonization with other species or other clones is infrequent. Independent of the underlying genotype, the CF lung habitat triggers a uniform, genetically fixed conversion of bacterial phenotype. Most CFP, aeruginosa strains become non-motile, mucoid

  15. Modified Pseudomonas agar: new differential medium for the detection/enumeration of Pseudomonas aeruginosa in mineral water.

    PubMed

    Ramalho, Rita; Cunha, Joaquim; Teixeira, Paula; Gibbs, Paul A

    2002-03-01

    Pseudomonas aeruginosa has been implicated as a foodborne and waterborne pathogen and is now considered a primary infectious agent. In the present study, the survival of P. aeruginosa inoculated in mineral water was evaluated by drop counts on Pseudomonas Agar Base (PAB), PAB with CN supplement X107, PAB with cetrimide, PAB with nalidixic acid, and these media with added FeSO(4). Initial counts, before starvation, were the same in all media tested. Following this period, P. aeruginosa became sensitive to PAB with added cetrimide. The addition of FeSO(4) did not improve the recovery of stressed P. aeruginosa but gave colonies a typical dark brown colour being easily differentiated from other species that can grow at 42 degrees C. The modified Pseudomonas agar medium was also tested with several P. aeruginosa strains, other species of Pseudomonas, and other genera. Only P. aeruginosa strains (pyocyanin positive) produced the typical colonies. Our results demonstrate that Pseudomonas agar with ferrous sulphate, used for the differentiation of P. aeruginosa colonies, and nalidixic acid, used as an inhibitor of Gram-positive bacteria, might be a useful medium for the detection of injured P. aeruginosa in mineral water. PMID:11777584

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

    PubMed

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

    2016-08-11

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

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  19. Modulation of biofilms of Pseudomonas aeruginosa by quinolones.

    PubMed Central

    Yassien, M; Khardori, N; Ahmedy, A; Toama, M

    1995-01-01

    The interaction between four fluoroquinolones (ciprofloxacin, norfloxacin, pefloxacin, and ofloxacin) and biofilms of Pseudomonas aeruginosa in wells of microtiter plates and on segments of vascular catheters were studied in an in vitro model of vascular catheter colonization. Subinhibitory concentrations (one-half, one-fourth, and one-eight of the MIC) of the fluoroquinolones reduced the adherence of P. aeruginosa to 30 to 33, 44 to 47, and 61 to 67% of that of controls, respectively. The addition of high concentrations of the fluoroquinolones (12.5 and 400 micrograms/ml) to preformed biofilms (grown for 48 h at 37 degrees C) decreased the adherence of P. aeruginosa to 69 to 77 and 39 to 60% of that of controls, respectively. In an in vitro model of vascular catheter colonization, subinhibitory concentrations (one-half, one-fourth, and one-eight of the MIC) of fluoroquinolones reduced the number of adherent bacteria to 21 to 23, 40 to 46, and 55 to 70% of that of the controls, respectively. Scanning electron microscopy demonstrated a significant reduction in glycocalyx formation and adherent bacteria in the presence of pefloxacin at one-half to one-eight of the MIC. Vascular catheter segments precolonized with P. aeruginosa for 24 h and exposed to the fluoroquinolones at 4 to 25 times the MIC (50 micrograms/ml) for 2 h showed <5% growth of adherent cells compared with controls. No adherent organisms were cultured in the presence of 8 to 50 times the MIC (100 micrograms/ml). Scanning electron microscopy studies of preformed biofilms exposed to pefloxacin verified the results obtained by culture. These data show that subinhibitory concentrations of ciprofloxacin, norfloxacin, pefloxacin, and ofloxacin inhibit the adherence of P. aeruginosa to plastic surfaces and vascular catheters. Clinically achievable concentrations of fluoroquinolones (50 to 100 micrograms/ml) were able to eradicate preformed biofilms on vascular catheters. PMID:8619580

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

    PubMed

    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 (p<0.001) indicating anti-virulent property attributing towards attenuation of virulence of P. aeruginosa. Further zingerone not only had marked effect on the production of quorum sensing signal molecules by clinical isolates of P. aeruginosa but also showed significant interference with the activation of QS reporter strains. To study the mechanism of blocking quorum sensing cascade, in silico analysis was carried out. Anti-QS activity was attributed to interference with the ligand receptor interaction of zingerone with QS receptors (TraR, LasR, RhlR and PqsR). Zingerone showed a good comparative docking score to respective autoinducer molecules which was even higher than that of vanillin, a proven anti-quorum sensing phytochemical. The results of the present study revealed the anti-quorum sensing activity of zingerone targeting ligand-receptor interaction, hence proposing zingerone as a suitable anti-virulent drug candidate against P. aeruginosa infections. PMID:25704369

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

    PubMed

    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 (p<0.001) indicating anti-virulent property attributing towards attenuation of virulence of P. aeruginosa. Further zingerone not only had marked effect on the production of quorum sensing signal molecules by clinical isolates of P. aeruginosa but also showed significant interference with the activation of QS reporter strains. To study the mechanism of blocking quorum sensing cascade, in silico analysis was carried out. Anti-QS activity was attributed to interference with the ligand receptor interaction of zingerone with QS receptors (TraR, LasR, RhlR and PqsR). Zingerone showed a good comparative docking score to respective autoinducer molecules which was even higher than that of vanillin, a proven anti-quorum sensing phytochemical. The results of the present study revealed the anti-quorum sensing activity of zingerone targeting ligand-receptor interaction, hence proposing zingerone as a suitable anti-virulent drug candidate against P. aeruginosa infections.

  2. Dissecting the Machinery That Introduces Disulfide Bonds in Pseudomonas aeruginosa

    PubMed Central

    Arts, Isabelle S.; Ball, Geneviève; Leverrier, Pauline; Garvis, Steven; Nicolaes, Valérie; Vertommen, Didier; Ize, Bérengère; Tamu Dufe, Veronica; Messens, Joris; Voulhoux, Romé; Collet, Jean-François

    2013-01-01

    ABSTRACT Disulfide bond formation is required for the folding of many bacterial virulence factors. However, whereas the Escherichia coli disulfide bond-forming system is well characterized, not much is known on the pathways that oxidatively fold proteins in pathogenic bacteria. Here, we report the detailed unraveling of the pathway that introduces disulfide bonds in the periplasm of the human pathogen Pseudomonas aeruginosa. The genome of P. aeruginosa uniquely encodes two DsbA proteins (P. aeruginosa DsbA1 [PaDsbA1] and PaDsbA2) and two DsbB proteins (PaDsbB1 and PaDsbB2). We found that PaDsbA1, the primary donor of disulfide bonds to secreted proteins, is maintained oxidized in vivo by both PaDsbB1 and PaDsbB2. In vitro reconstitution of the pathway confirms that both PaDsbB1 and PaDsbB2 shuttle electrons from PaDsbA1 to membrane-bound quinones. Accordingly, deletion of both P. aeruginosa dsbB1 (PadsbB1) and PadsbB2 is required to prevent the folding of several P. aeruginosa virulence factors and to lead to a significant decrease in pathogenicity. Using a high-throughput proteomic approach, we also analyzed the impact of PadsbA1 deletion on the global periplasmic proteome of P. aeruginosa, which allowed us to identify more than 20 new potential substrates of this major oxidoreductase. Finally, we report the biochemical and structural characterization of PaDsbA2, a highly oxidizing oxidoreductase, which seems to be expressed under specific conditions. By fully dissecting the machinery that introduces disulfide bonds in P. aeruginosa, our work opens the way to the design of novel antibacterial molecules able to disarm this pathogen by preventing the proper assembly of its arsenal of virulence factors. PMID:24327342

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

    PubMed Central

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

    1994-01-01

    Alginate is a viscous extracellular polymer produced by mucoid strains of Pseudomonas aeruginosa that cause chronic pulmonary infections in patients with cystic fibrosis. Alginate is polymerized from GDP-mannuronate to a linear polymer of beta-1-4-linked residues of D-mannuronate and its C5-epimer, L-guluronate. We previously identified a gene called algG in the alginate biosynthetic operon that is required for incorporation of L-guluronate residues into alginate. In this study, we tested the hypothesis that the product of algG is a C5-epimerase that directly converts D-mannuronate to L-guluronate. The DNA sequence of algG was determined, and an open reading frame encoding a protein (AlgG) of approximately 60 kDa was identified. The inferred amino terminus of AlgG protein contained a putative signal sequence of 35 amino acids. Expression of algG in Escherichia coli demonstrated both 60-kDa pre-AlgG and 55-kDa mature AlgG proteins, the latter of which was localized to the periplasm. An N-terminal analysis of AlgG showed that the signal sequence was removed in the mature form. Pulse-chase experiments in both E. coli and P. aeruginosa provided evidence for conversion of the 60- to the 55-kDa size in vivo. Expression of algG from a plasmid inan algG (i.e., polymannuronate-producing) mutant of P. aeruginosa restored production of an alginate containing L-guluronate residues. The observation that AlgG is apparently processed and exported from the cytoplasm suggested that it may act as a polymer-level mannuronan C5-epimerase. An in vitro assay for mannuronan C5 epimerization was developed wherein extracts of E. coli expressing high levels of AlgG were incubated with polymannuronate. Epimerization of D-mannuronate to L-guluronate residues in the polymer was detected enzymatically, using a L-guluronate-specific alginate lyase of Klebsiella aerogenes. Epimerization was also detected in the in vitro reaction between recombinant AlgG and poly-D-mannuronate, using high

  4. Dictyostelium discoideum as a surrogate host-microbe model for antivirulence screening in Pseudomonas aeruginosa PAO1.

    PubMed

    Bravo-Toncio, Catalina; Álvarez, Javiera A; Campos, Francisca; Ortíz-Severín, Javiera; Varas, Macarena; Cabrera, Ricardo; Lagos, Carlos F; Chávez, Francisco P

    2016-05-01

    The interest of the pharmaceutical industry in developing new antibiotics is decreasing, as established screening systems which identify compounds that kill or inhibit the growth of bacteria can no longer be used. Consequently, antimicrobial screening using classical minimum inhibitory concentration (MIC) measurements is becoming obsolete. The discovery of antimicrobial agents that specifically target a bacterial pathogen without affecting the host and its beneficial bacteria is a promising strategy. However, few host-microbe models are available for in vivo screening of novel antivirulence molecules. Here we designed high-throughput developmental assays in the social amoeba Dictyostelium discoideum to measure Pseudomonas aeruginosa virulence and to screen for novel antivirulence molecules without side effects to the host and its beneficial bacteria Klebsiella aerogenes. Thirty compounds were evaluated that had been previously selected by virtual screening for inhibitors of P. aeruginosa PAO1 polyphosphate kinase 1 (PaPPK1) and diverse compounds with combined PPK1 inhibitory and antivirulence activities were identified. This approach demonstrates that D. discoideum is a suitable surrogate host for preliminary high-throughput screening of antivirulence agents and that PPK1 is a suitable target for developing novel antivirulence compounds that can be further validated in mammalian models. PMID:27066943

  5. Dictyostelium discoideum as a surrogate host-microbe model for antivirulence screening in Pseudomonas aeruginosa PAO1.

    PubMed

    Bravo-Toncio, Catalina; Álvarez, Javiera A; Campos, Francisca; Ortíz-Severín, Javiera; Varas, Macarena; Cabrera, Ricardo; Lagos, Carlos F; Chávez, Francisco P

    2016-05-01

    The interest of the pharmaceutical industry in developing new antibiotics is decreasing, as established screening systems which identify compounds that kill or inhibit the growth of bacteria can no longer be used. Consequently, antimicrobial screening using classical minimum inhibitory concentration (MIC) measurements is becoming obsolete. The discovery of antimicrobial agents that specifically target a bacterial pathogen without affecting the host and its beneficial bacteria is a promising strategy. However, few host-microbe models are available for in vivo screening of novel antivirulence molecules. Here we designed high-throughput developmental assays in the social amoeba Dictyostelium discoideum to measure Pseudomonas aeruginosa virulence and to screen for novel antivirulence molecules without side effects to the host and its beneficial bacteria Klebsiella aerogenes. Thirty compounds were evaluated that had been previously selected by virtual screening for inhibitors of P. aeruginosa PAO1 polyphosphate kinase 1 (PaPPK1) and diverse compounds with combined PPK1 inhibitory and antivirulence activities were identified. This approach demonstrates that D. discoideum is a suitable surrogate host for preliminary high-throughput screening of antivirulence agents and that PPK1 is a suitable target for developing novel antivirulence compounds that can be further validated in mammalian models.

  6. Strategies for improved rhamnolipid production by Pseudomonas aeruginosa PA1

    PubMed Central

    Pereira Jr, Nei; Freire, Denise M.G.

    2016-01-01

    Rhamnolipids are biosurfactants with potential for diversified industrial and environmental uses. The present study evaluated three strategies for increasing the production of rhamnolipid-type biosurfactants produced by Pseudomonas aeruginosa strain PA1. The influence of pH, the addition of P. aeruginosa spent culture medium and the use of a fed-batch process were examined. The culture medium adjusted to pH 7.0 was the most productive. Furthermore, the pH of the culture medium had a measurable effect on the ratio of synthesized mono- and dirhamnolipids. At pH values below 7.3, the proportion of monorhamnolipids decreased from 45 to 24%. The recycling of 20% of the spent culture medium in where P. aeruginosa was grown up to the later stationary phase was responsible for a 100% increase in rhamnolipid volumetric productivity in the new culture medium. Finally, the use of fed-batch operation under conditions of limited nitrogen resulted in a 3.8-fold increase in the amount of rhamnolipids produced (2.9 g L−1–10.9 g L−1). These results offer promising pathways for the optimization of processes for the production of rhamnolipids. PMID:27257553

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

    PubMed

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

    2016-01-01

    Pseudomonas aeruginosa causes acute and chronic infections in human. Its increasing resistance to antibiotics requires alternative treatments that are more effective than available strategies. Among the alternatives is the unconventional usage of conventional antibiotics, of which the macrolide antibiotic azithromycin (AZM) provides a paradigmatic example. AZM therapy is associated with a small but consistent improvement in respiratory function of cystic fibrosis patients suffering from chronic P. aeruginosa infection. Besides immunomodulating activities, AZM represses bacterial genes involved in virulence, quorum sensing, biofilm formation, and motility, all of which are due to stalling of ribosome and depletion of cellular tRNA pool. However, how P. aeruginosa responds to and counteracts the effects of AZM remain elusive. Here, we found that deficiency of PA3297, a gene encoding a DEAH-box helicase, intensified AZM-mediated bacterial killing, suppression of pyocyanin production and swarming motility, and hypersusceptibility to hydrogen peroxide. We demonstrated that expression of PA3297 is induced by the interaction between AZM and ribosome. Importantly, mutation of PA3297 resulted in elevated levels of unprocessed 23S-5S rRNA in the presence of AZM, which might lead to increased susceptibility to AZM-mediated effects. Our results revealed one of the bacterial responses in counteracting the detrimental effects of AZM. PMID:27014238

  8. Aerobic biodegradation pathway for Remazol Orange by Pseudomonas aeruginosa.

    PubMed

    Sarayu, K; Sandhya, S

    2010-02-01

    Removal of azo dyes from effluent generated by textile industries is rather difficult. Azo dyes represent a major class of synthetic colorants that are mutagenic and carcinogenic. Pseudomonas aeruginosa grew well in the presence of Remazol Orange (RO) and was able to decolorize and degrade it. In the present study, the decolorization and degradation efficiency using single culture P. aeruginosa with RO and textile wastewaters is studied. The elucidation of decolorization pathway for P. aeruginosa is of special interest. The degradation pathway and the metabolic products formed during the degradation were also predicted with the help of high performance liquid chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy analysis. The data show the cleavage of the azo dye RO to form both methyl metanilic acid and 4-aminobenzoic acid after decolorization and finally to oxidation forms benzoic acid, alkenes, aldehydes, and alkynes. The organism was able to decolorize the dye RO and wastewater effectively to the maximum of 82.4% and 62%, respectively.

  9. Indole and 7‐hydroxyindole diminish Pseudomonas aeruginosa virulence

    PubMed Central

    Lee, Jintae; Attila, Can; Cirillo, Suat L. G.; Cirillo, Jeffrey D.; Wood, Thomas K.

    2009-01-01

    Summary Indole is an extracellular biofilm signal for Escherichia coli, and many bacterial oxygenases readily convert indole to various oxidized compounds including 7‐hydroxyindole (7HI). Here we investigate the impact of indole and 7HI on Pseudomonas aeruginosa PAO1 virulence and quorum sensing (QS)‐regulated phenotypes; this strain does not synthesize these compounds but degrades them rapidly. Indole and 7HI both altered extensively gene expression in a manner opposite that of acylhomoserine lactones; the most repressed genes encode the mexGHI‐opmD multidrug efflux pump and genes involved in the synthesis of QS‐regulated virulence factors including pyocyanin (phz operon), 2‐heptyl‐3‐hydroxy‐4(1H)‐quinolone (PQS) signal (pqs operon), pyochelin (pch operon) and pyoverdine (pvd operon). Corroborating these microarray results, indole and 7HI decreased production of pyocyanin, rhamnolipid, PQS and pyoverdine and enhanced antibiotic resistance. In addition, indole affected the utilization of carbon, nitrogen and phosphorus, and 7HI abolished swarming motility. Furthermore, 7HI reduced pulmonary colonization of P. aeruginosa in guinea pigs and increased clearance in lungs. Hence, indole‐related compounds have potential as a novel antivirulence approach for the recalcitrant pathogen P. aeruginosa. PMID:21261883

  10. Rhamnolipids Modulate Swarming Motility Patterns of Pseudomonas aeruginosa

    PubMed Central

    Caiazza, Nicky C.; Shanks, Robert M. Q.; O'Toole, G. A.

    2005-01-01

    Pseudomonas aeruginosa is capable of twitching, swimming, and swarming motility. The latter form of translocation occurs on semisolid surfaces, requires functional flagella and biosurfactant production, and results in complex motility patterns. From the point of inoculation, bacteria migrate as defined groups, referred to as tendrils, moving in a coordinated manner capable of sensing and responding to other groups of cells. We were able to show that P. aeruginosa produces extracellular factors capable of modulating tendril movement, and genetic analysis revealed that modulation of these movements was dependent on rhamnolipid biosynthesis. An rhlB mutant (deficient in mono- and dirhamnolipid production) and an rhlC mutant (deficient in dirhamnolipid production) exhibited altered swarming patterns characterized by irregularly shaped tendrils. In addition, agar supplemented with rhamnolipid-containing spent supernatant inhibited wild-type (WT) swarming, whereas agar supplemented with spent supernatant from mutants that do not make rhamnolipids had no effect on WT P. aeruginosa swarming. Addition of purified rhamnolipids to swarming medium also inhibited swarming motility of the WT strain. We also show that a sadB mutant does not sense and/or respond to other groups of swarming cells and this mutant was capable of swarming on media supplemented with rhamnolipid-containing spent supernatant or purified rhamnolipids. The abilities to produce and respond to rhamnolipids in the context of group behavior are discussed. PMID:16237018

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

    PubMed

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

    2014-02-01

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

  12. Distinct synergistic action of piperacillin and methylglyoxal against Pseudomonas aeruginosa.

    PubMed

    Mukherjee, Sayanti; Chaki, Shaswati; Das, Sukhen; Sen, Saswati; Dutta, Samir Kr; Dastidar, Sujata G

    2011-07-01

    The dicarbonyl compound methylglyoxal is a natural constituent of Manuka honey produced from Manuka flowers in New Zealand. It is known to possess both anticancer and antibacterial activity. Such observations prompted to investigate the ability of methylglyoxal as a potent drug against multidrug resistant Pseudomonas aeruginosa. A total of 12 test P. aeruginosa strains isolated from various hospitals were tested for their resistances against many antibiotics, most of which are applied in the treatment of P. aeruginosa infections. Results revealed that the strains were resistant to many drugs at high levels, only piperacillin, carbenicillin, amikacin and ciprofloxacin showed resistances at comparatively lower levels. Following multiple experimentations it was observed that methylglyoxal was also antimicrobic against all the strains at comparable levels. Distinct and statistically significant synergism was observed between methylglyoxal and piperacillin by disc diffusion tests when compared with their individual effects. The fractional inhibitory concentration index of this combination evaluated by checkerboard analysis, was 0.5, which confirmed synergism between the pair. Synergism was also noted when methylglyoxal was combined with carbenicillin and amikacin. PMID:21800506

  13. Pseudomonas aeruginosa immunotype 5 polysaccharide-toxin A conjugate vaccine.

    PubMed Central

    Cryz, S J; Furer, E; Sadoff, J C; Germanier, R

    1986-01-01

    Polysaccharide (PS) derived from Pseudomonas aeruginosa immunotype 5 lipopolysaccharide was covalently coupled to toxin A by reductive amination with adipic acid dihydrazide as a spacer molecule. The resulting PS-toxin A conjugate was composed of 27.5% PS and 72.5% toxin A. The conjugate was composed of heterogeneous high-molecular-weight species, all of which possessed an Mr greater than 670,000. The conjugate was nontoxic for mice and nonpyrogenic at a dose of 50 micrograms/kg of body weight when intravenously administered to rabbits. Immunization of rabbits with the conjugate evoked both an antilipopolysaccharide immunoglobulin G (IgG) and an anti-toxin A IgG response. Anticonjugate IgG was capable of neutralizing the cytotoxic effect of toxin A. Immunization of mice with the conjugate increased the mean lethal dose from 4.5 X 10(1) P. aeruginosa for control mice to 9.6 X 10(5) P. aeruginosa for vaccinated mice. Similarly, immunization raised the mean lethal dose for toxin A from 0.2 to 4.67 micrograms per mouse. PMID:3082756

  14. Origin and Impact of Nitric Oxide in Pseudomonas aeruginosa Biofilms

    PubMed Central

    2015-01-01

    The formation of the organized bacterial community called biofilm is a crucial event in bacterial physiology. Given that biofilms are often refractory to antibiotics and disinfectants to which planktonic bacteria are susceptible, their formation is also an industrially and medically relevant issue. Pseudomonas aeruginosa, a well-known human pathogen causing acute and chronic infections, is considered a model organism to study biofilms. A large number of environmental cues control biofilm dynamics in bacterial cells. In particular, the dispersal of individual cells from the biofilm requires metabolic and morphological reprogramming in which the second messenger bis-(3′-5′)-cyclic dimeric GMP (c-di-GMP) plays a central role. The diatomic gas nitric oxide (NO), a well-known signaling molecule in both prokaryotes and eukaryotes, is able to induce the dispersal of P. aeruginosa and other bacterial biofilms by lowering c-di-GMP levels. In this review, we summarize the current knowledge on the molecular mechanisms connecting NO sensing to the activation of c-di-GMP-specific phosphodiesterases in P. aeruginosa, ultimately leading to c-di-GMP decrease and biofilm dispersal. PMID:26260455

  15. Strategies for improved rhamnolipid production by Pseudomonas aeruginosa PA1.

    PubMed

    Soares Dos Santos, Alexandre; Pereira, Nei; Freire, Denise M G

    2016-01-01

    Rhamnolipids are biosurfactants with potential for diversified industrial and environmental uses. The present study evaluated three strategies for increasing the production of rhamnolipid-type biosurfactants produced by Pseudomonas aeruginosa strain PA1. The influence of pH, the addition of P. aeruginosa spent culture medium and the use of a fed-batch process were examined. The culture medium adjusted to pH 7.0 was the most productive. Furthermore, the pH of the culture medium had a measurable effect on the ratio of synthesized mono- and dirhamnolipids. At pH values below 7.3, the proportion of monorhamnolipids decreased from 45 to 24%. The recycling of 20% of the spent culture medium in where P. aeruginosa was grown up to the later stationary phase was responsible for a 100% increase in rhamnolipid volumetric productivity in the new culture medium. Finally, the use of fed-batch operation under conditions of limited nitrogen resulted in a 3.8-fold increase in the amount of rhamnolipids produced (2.9 g L(-1)-10.9 g L(-1)). These results offer promising pathways for the optimization of processes for the production of rhamnolipids.

  16. PA3297 Counteracts Antimicrobial Effects of Azithromycin in Pseudomonas aeruginosa

    PubMed Central

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

    2016-01-01

    Pseudomonas aeruginosa causes acute and chronic infections in human. Its increasing resistance to antibiotics requires alternative treatments that are more effective than available strategies. Among the alternatives is the unconventional usage of conventional antibiotics, of which the macrolide antibiotic azithromycin (AZM) provides a paradigmatic example. AZM therapy is associated with a small but consistent improvement in respiratory function of cystic fibrosis patients suffering from chronic P. aeruginosa infection. Besides immunomodulating activities, AZM represses bacterial genes involved in virulence, quorum sensing, biofilm formation, and motility, all of which are due to stalling of ribosome and depletion of cellular tRNA pool. However, how P. aeruginosa responds to and counteracts the effects of AZM remain elusive. Here, we found that deficiency of PA3297, a gene encoding a DEAH-box helicase, intensified AZM-mediated bacterial killing, suppression of pyocyanin production and swarming motility, and hypersusceptibility to hydrogen peroxide. We demonstrated that expression of PA3297 is induced by the interaction between AZM and ribosome. Importantly, mutation of PA3297 resulted in elevated levels of unprocessed 23S-5S rRNA in the presence of AZM, which might lead to increased susceptibility to AZM-mediated effects. Our results revealed one of the bacterial responses in counteracting the detrimental effects of AZM. PMID:27014238

  17. Mycofabricated biosilver nanoparticles interrupt Pseudomonas aeruginosa quorum sensing systems.

    PubMed

    Singh, Braj R; Singh, Brahma N; Singh, Akanksha; Khan, Wasi; Naqvi, Alim H; Singh, Harikesh B

    2015-01-01

    Quorum sensing (QS) is a chemical communication process that Pseudomonas aeruginosa uses to regulate virulence and biofilm formation. Disabling of QS is an emerging approach for combating its pathogenicity. Silver nanoparticles (AgNPs) have been widely applied as antimicrobial agents against human pathogenic bacteria and fungi, but not for the attenuation of bacterial QS. Here we mycofabricated AgNPs (mfAgNPs) using metabolites of soil fungus Rhizopus arrhizus BRS-07 and tested their effect on QS-regulated virulence and biofilm formation of P. aeruginosa. Transcriptional studies demonstrated that mfAgNPs reduced the levels of LasIR-RhlIR. Treatment of mfAgNPs inhibited biofilm formation, production of several virulence factors (e.g. LasA protease, LasB elastrase, pyocyanin, pyoverdin, pyochelin, rhamnolipid, and alginate) and reduced AHLs production. Further genes quantification analyses revealed that mfAgNPs significantly down-regulated QS-regulated genes, specifically those encoded to the secretion of virulence factors. The results clearly indicated the anti-virulence property of mfAgNPs by inhibiting P. aeruginosa QS signaling. PMID:26347993

  18. Mycofabricated biosilver nanoparticles interrupt Pseudomonas aeruginosa quorum sensing systems

    PubMed Central

    Singh, Braj R.; Singh, Brahma N.; Singh, Akanksha; Khan, Wasi; Naqvi, Alim H.; Singh, Harikesh B.

    2015-01-01

    Quorum sensing (QS) is a chemical communication process that Pseudomonas aeruginosa uses to regulate virulence and biofilm formation. Disabling of QS is an emerging approach for combating its pathogenicity. Silver nanoparticles (AgNPs) have been widely applied as antimicrobial agents against human pathogenic bacteria and fungi, but not for the attenuation of bacterial QS. Here we mycofabricated AgNPs (mfAgNPs) using metabolites of soil fungus Rhizopus arrhizus BRS-07 and tested their effect on QS-regulated virulence and biofilm formation of P. aeruginosa. Transcriptional studies demonstrated that mfAgNPs reduced the levels of LasIR-RhlIR. Treatment of mfAgNPs inhibited biofilm formation, production of several virulence factors (e.g. LasA protease, LasB elastrase, pyocyanin, pyoverdin, pyochelin, rhamnolipid, and alginate) and reduced AHLs production. Further genes quantification analyses revealed that mfAgNPs significantly down-regulated QS-regulated genes, specifically those encoded to the secretion of virulence factors. The results clearly indicated the anti-virulence property of mfAgNPs by inhibiting P. aeruginosa QS signaling. PMID:26347993

  19. Strategies for improved rhamnolipid production by Pseudomonas aeruginosa PA1.

    PubMed

    Soares Dos Santos, Alexandre; Pereira, Nei; Freire, Denise M G

    2016-01-01

    Rhamnolipids are biosurfactants with potential for diversified industrial and environmental uses. The present study evaluated three strategies for increasing the production of rhamnolipid-type biosurfactants produced by Pseudomonas aeruginosa strain PA1. The influence of pH, the addition of P. aeruginosa spent culture medium and the use of a fed-batch process were examined. The culture medium adjusted to pH 7.0 was the most productive. Furthermore, the pH of the culture medium had a measurable effect on the ratio of synthesized mono- and dirhamnolipids. At pH values below 7.3, the proportion of monorhamnolipids decreased from 45 to 24%. The recycling of 20% of the spent culture medium in where P. aeruginosa was grown up to the later stationary phase was responsible for a 100% increase in rhamnolipid volumetric productivity in the new culture medium. Finally, the use of fed-batch operation under conditions of limited nitrogen resulted in a 3.8-fold increase in the amount of rhamnolipids produced (2.9 g L(-1)-10.9 g L(-1)). These results offer promising pathways for the optimization of processes for the production of rhamnolipids. PMID:27257553

  20. Response surface methodology for cadmium biosorption on Pseudomonas aeruginosa.

    PubMed

    Ahmady-Asbchin, Salman

    2016-01-01

    In this research the effects of various physicochemical factors on Cd(2+) biosorption such as initial metal concentration, pH and contact exposure time were studied. This study has shown a Cd(2+) biosorption, equilibrium time of about 5 min for Pseudomonas aeruginosa and the adsorption equilibrium data were well described by Langmuir equation. The maximum capacity for biosorption has been extrapolated to 0.56 mmol.g(-1) for P. aeruginosa. The thermodynamic properties ΔG(0), ΔH(0), and ΔS(0) of Cd(2+) for biosorption were analyzed by the equilibrium constant value obtained from experimented data at different temperatures. The results show that biosorption of Cd(2+) by P. aeruginosa are endothermic and spontaneous with ΔH value of 36.35 J.mol(-1). By response surface methodology, the quadratic model has adequately described the experimental data based on the adjusted determination coefficient (R(2) = 0.98). The optimum conditions for maximum uptake onto the biosorbent were established at 0.5 g.l(-1) biosorbent concentration, pH 6 for the aqueous solution, and a temperature of 30 °C. PMID:27232396

  1. Mechanism of azithromycin inhibition of HSL synthesis in Pseudomonas aeruginosa.

    PubMed

    Zeng, Jianming; Zhang, Ni; Huang, Bin; Cai, Renxin; Wu, Binning; E, Shunmei; Fang, Chengcai; Chen, Cha

    2016-04-14

    Pseudomonas aeruginosa is an opportunistic pathogen and a leading cause of nosocomial infections. Unfortunately, P. aeruginosa has low antibiotic susceptibility due to several chromosomally encoded antibiotic resistance genes. Hence, we carried out mechanistic studies to determine how azithromycin affects quorum sensing and virulence in P. aeruginosa. lasI and rhlI single and double mutants were constructed. We then undertook a quantitative approach to determine the optimal concentration of azithromycin and culture time that can affect the expression of HSLs. Furthermore, based on the above results, the effect on quorum sensing was analyzed at a transcriptional level. It was found that 2 μg/mL azithromycin caused a 79% decrease in 3-oxo-C12-HSL secretion during cultivation, while C4-HSL secretion was strongly repressed in the early stages. Azithromycin acts on ribosomes; to determine whether this can elicit alternative modes of gene expression, transcriptional regulation of representative virulence genes was analyzed. We propose a new relationship for lasI and rhlI: lasI acts as a cell density sensor, and rhlI functions as a fine-tuning mechanism for coordination between different quorum sensing systems.

  2. Indole and 7-hydroxyindole diminish Pseudomonas aeruginosa virulence.

    PubMed

    Lee, Jintae; Attila, Can; Cirillo, Suat L G; Cirillo, Jeffrey D; Wood, Thomas K

    2009-01-01

    Indole is an extracellular biofilm signal for Escherichia coli, and many bacterial oxygenases readily convert indole to various oxidized compounds including 7-hydroxyindole (7HI). Here we investigate the impact of indole and 7HI on Pseudomonas aeruginosa PAO1 virulence and quorum sensing (QS)-regulated phenotypes; this strain does not synthesize these compounds but degrades them rapidly. Indole and 7HI both altered extensively gene expression in a manner opposite that of acylhomoserine lactones; the most repressed genes encode the mexGHI-opmD multidrug efflux pump and genes involved in the synthesis of QS-regulated virulence factors including pyocyanin (phz operon), 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS) signal (pqs operon), pyochelin (pch operon) and pyoverdine (pvd operon). Corroborating these microarray results, indole and 7HI decreased production of pyocyanin, rhamnolipid, PQS and pyoverdine and enhanced antibiotic resistance. In addition, indole affected the utilization of carbon, nitrogen and phosphorus, and 7HI abolished swarming motility. Furthermore, 7HI reduced pulmonary colonization of P. aeruginosa in guinea pigs and increased clearance in lungs. Hence, indole-related compounds have potential as a novel antivirulence approach for the recalcitrant pathogen P. aeruginosa. PMID:21261883

  3. Evolutionary genomics of epidemic and nonepidemic strains of Pseudomonas aeruginosa

    PubMed Central

    Dettman, Jeremy R.; Rodrigue, Nicolas; Aaron, Shawn D.; Kassen, Rees

    2013-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen of humans and is a major cause of morbidity and mortality in patients with cystic fibrosis (CF). Prolonged infection of the respiratory tract can lead to adaptation of the pathogen to the CF lung environment. To examine the general patterns of adaptation associated with chronic infection, we obtained genome sequences from a collection of P. aeruginosa isolated from airways of patients with CF. Our analyses support a nonclonal epidemic population structure, with a background of unique, recombining genotypes, and the rare occurrence of successful epidemic clones. We present unique genome sequence evidence for the intercontinental spread of an epidemic strain shared between CF clinics in the United Kingdom and North America. Analyses of core and accessory genomes identified candidate genes and important functional pathways associated with adaptive evolution. Many genes of interest were involved in biological functions with obvious roles in this pathosystem, such as biofilm formation, antibiotic metabolism, pathogenesis, transport, reduction/oxidation, and secretion. Key factors driving the adaptive evolution of this pathogen within the host appear to be the presence of oxidative stressors and antibiotics. Regions of the accessory genome unique to the epidemic strain were enriched for genes in transporter families that efflux heavy metals and antibiotics. The epidemic strain was significantly more resistant than nonepidemic strains to three different antibiotics. Multiple lines of evidence suggest that selection imposed by the CF lung environment has a major influence on genomic evolution and the genetic characteristics of P. aeruginosa isolates causing contemporary infection. PMID:24324153

  4. Quorum sensing and policing of Pseudomonas aeruginosa social cheaters.

    PubMed

    Wang, Meizhen; Schaefer, Amy L; Dandekar, Ajai A; Greenberg, E Peter

    2015-02-17

    The bacterium Pseudomonas aeruginosa is an opportunistic human pathogen that uses a quorum sensing signal cascade to activate expression of dozens of genes when sufficient population densities have been reached. Quorum sensing controls production of several key virulence factors, including secreted proteases such as elastase. Cooperating groups of bacteria growing on protein are susceptible to social cheating by quorum-sensing defective mutants. A possible way to restrict cheater emergence is by policing where cooperators produce costly goods to sanction or punish cheats. The P. aeruginosa LasR-LasI quorum sensing system controls genes including those encoding proteases and also those encoding a second quorum-sensing system, the RhlR-RhlI system, which controls numerous genes including those for cyanide production. By using RhlR quorum sensing mutants and cyanide synthesis mutants, we show that cyanide production is costly and cyanide-producing cooperators use cyanide to punish LasR-null social cheaters. Cooperators are less susceptible to cyanide than are LasR mutants. These experiments demonstrate policing in P. aeruginosa, provide a mechanistic understanding of policing, and show policing involves the cascade organization of the two quorum sensing systems in this bacterium.

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  7. Use of an ultraviolet light at point-of-dispense faucet to eliminate Pseudomonas aeruginosa.

    PubMed

    Gerba, Charles P

    2015-05-01

    Tap water is believed to be a significant source of Pseudomonas aeruginosa in health care environments. This study evaluated an ultraviolet (UV) light point-of-dispense water treatment system for control of P aeruginosa. No P aeruginosa was detected in 30 different water dispensers in which the UV light device had been operating for 1-34 months. In comparison, P aeruginosa was found in other taps that did not feature this UV light system. PMID:25721063

  8. Use of an ultraviolet light at point-of-dispense faucet to eliminate Pseudomonas aeruginosa.

    PubMed

    Gerba, Charles P

    2015-05-01

    Tap water is believed to be a significant source of Pseudomonas aeruginosa in health care environments. This study evaluated an ultraviolet (UV) light point-of-dispense water treatment system for control of P aeruginosa. No P aeruginosa was detected in 30 different water dispensers in which the UV light device had been operating for 1-34 months. In comparison, P aeruginosa was found in other taps that did not feature this UV light system.

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

    PubMed

    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

  10. Genetics of O-Antigen Biosynthesis in Pseudomonas aeruginosa

    PubMed Central

    Rocchetta, H. L.; Burrows, L. L.; Lam, J. S.

    1999-01-01

    Pathogenic bacteria produce an elaborate assortment of extracellular and cell-associated bacterial products that enable colonization and establishment of infection within a host. Lipopolysaccharide (LPS) molecules are cell surface factors that are typically known for their protective role against serum-mediated lysis and their endotoxic properties. The most heterogeneous portion of LPS is the O antigen or O polysaccharide, and it is this region which confers serum resistance to the organism. Pseudomonas aeruginosa is capable of concomitantly synthesizing two types of LPS referred to as A band and B band. The A-band LPS contains a conserved O polysaccharide region composed of d-rhamnose (homopolymer), while the B-band O-antigen (heteropolymer) structure varies among the 20 O serotypes of P. aeruginosa. The genes coding for the enzymes that direct the synthesis of these two O antigens are organized into two separate clusters situated at different chromosomal locations. In this review, we summarize the organization of these two gene clusters to discuss how A-band and B-band O antigens are synthesized and assembled by dedicated enzymes. Examples of unique proteins required for both A-band and B-band O-antigen synthesis and for the synthesis of both LPS and alginate are discussed. The recent identification of additional genes within the P. aeruginosa genome that are homologous to those in the A-band and B-band gene clusters are intriguing since some are able to influence O-antigen synthesis. These studies demonstrate that P. aeruginosa represents a unique model system, allowing studies of heteropolymeric and homopolymeric O-antigen synthesis, as well as permitting an examination of the interrelationship of the synthesis of LPS molecules and other virulence determinants. PMID:10477307

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

    PubMed

    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.

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

    PubMed

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

    2016-09-01

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

  13. Pseudomonas aeruginosa KUCD1, a possible candidate for cadmium bioremediation

    PubMed Central

    Sinha, Sangram; Mukherjee, Samir Kumar

    2009-01-01

    A cadmium (8 mM) resistant Pseudomonas aeruginosa strain KUCd1 exhibiting high Cd accumulation under in vitro aerobic condition has been reported. The isolate showed a significant ability to remove more than 75% and 89% of the soluble cadmium during the active growth phase from the growth medium and from Cd-amended industrial wastewater under growth supportive condition. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDXS) suggest the presence of Cd in the cells from mid stationary phase. The cell fractionation study revealed membrane and periplasm to be the major accumulating site in this strain. The chemical nature of the accumulated Cd was studied by X-ray powder diffraction analysis. PMID:24031411

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

    PubMed

    Maderova, Zdenka; Horska, Katerina; Kim, Sang-Ryoung; Lee, Chung-Hak; Pospiskova, Kristyna; Safarikova, Mirka; Safarik, Ivo

    2016-01-01

    The formation of bacterial biofilm on various surfaces has significant negative economic effects. The aim of this study was to find a simple procedure to decrease the Pseudomonas aeruginosa biofilm formation in a water environment by using different food waste biological materials as signal molecule adsorbents. The selected biomaterials did not reduce the cell growth but affected biofilm formation. Promising biomaterials were magnetically modified in order to simplify manipulation and facilitate their magnetic separation. The best biocomposite, magnetically modified spent grain, exhibited substantial adsorption of signal molecules and decreased the biofilm formation. These results suggest that selected food waste materials and their magnetically responsive derivatives could be applied to solve biofilm problems in water environment. PMID:27148715

  15. Novel Multiscale Modeling Tool Applied to Pseudomonas aeruginosa Biofilm Formation

    PubMed Central

    Biggs, Matthew B.; Papin, Jason A.

    2013-01-01

    Multiscale modeling is used to represent biological systems with increasing frequency and success. Multiscale models are often hybrids of different modeling frameworks and programming languages. We present the MATLAB-NetLogo extension (MatNet) as a novel tool for multiscale modeling. We demonstrate the utility of the tool with a multiscale model of Pseudomonas aeruginosa biofilm formation that incorporates both an agent-based model (ABM) and constraint-based metabolic modeling. The hybrid model correctly recapitulates oxygen-limited biofilm metabolic activity and predicts increased growth rate via anaerobic respiration with the addition of nitrate to the growth media. In addition, a genome-wide survey of metabolic mutants and biofilm formation exemplifies the powerful analyses that are enabled by this computational modeling tool. PMID:24147108

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

    PubMed

    Maderova, Zdenka; Horska, Katerina; Kim, Sang-Ryoung; Lee, Chung-Hak; Pospiskova, Kristyna; Safarikova, Mirka; Safarik, Ivo

    2016-01-01

    The formation of bacterial biofilm on various surfaces has significant negative economic effects. The aim of this study was to find a simple procedure to decrease the Pseudomonas aeruginosa biofilm formation in a water environment by using different food waste biological materials as signal molecule adsorbents. The selected biomaterials did not reduce the cell growth but affected biofilm formation. Promising biomaterials were magnetically modified in order to simplify manipulation and facilitate their magnetic separation. The best biocomposite, magnetically modified spent grain, exhibited substantial adsorption of signal molecules and decreased the biofilm formation. These results suggest that selected food waste materials and their magnetically responsive derivatives could be applied to solve biofilm problems in water environment.

  17. Virulence attributes in Brazilian clinical isolates of Pseudomonas aeruginosa.

    PubMed

    Silva, Lívia V; Galdino, Anna Clara M; Nunes, Ana Paula F; dos Santos, Kátia R N; Moreira, Beatriz M; Cacci, Luciana C; Sodré, Cátia L; Ziccardi, Mariangela; Branquinha, Marta H; Santos, André L S

    2014-11-01

    Pseudomonas aeruginosa is an opportunistic human pathogen responsible for causing a huge variety of acute and chronic infections with significant levels of morbidity and mortality. Its success as a pathogen comes from its genetic/metabolic plasticity, intrinsic/acquired antimicrobial resistance, capacity to form biofilm and expression of numerous virulence factors. Herein, we have analyzed the genetic variability, antimicrobial susceptibility as well as the production of metallo-β-lactamases (MBLs) and virulence attributes (elastase, pyocyanin and biofilm) in 96 strains of P. aeruginosa isolated from different anatomical sites of patients attended at Brazilian hospitals. Our results revealed a great genetic variability, in which 86 distinct RAPD types (89.6% of polymorphisms) were detected. Regarding the susceptibility profile, 48 strains (50%) were resistant to the antimicrobials, as follows: 22.92% to the three tested antibiotics, 12.5% to both imipenem and meropenem, 11.46% to ceftazidime only, 2.08% to imipenem only and 1.04% to both ceftazidime and meropenem. Out of the 34 clinical strains of P. aeruginosa resistant to both imipenem and meropenem, 25 (73.53%) were MBL producers by phenotypic method while 12 (35.29%) were PCR positive for the MBL gene SPM-1. All P. aeruginosa strains produced pyocyanin, elastase and biofilm, although in different levels. Some associations were demonstrated among the susceptibility and/or production of these virulence traits with the anatomical site of strain isolation. For instance, almost all strains isolated from urine (85.71%) were resistant to the three antibiotics, while the vast majority of strains isolated from rectum (95%) and mouth (66.67%) were susceptible to all tested antibiotics. Urine isolates produced the highest pyocyanin concentration (20.15±5.65 μg/ml), while strains isolated from pleural secretion and mouth produced elevated elastase activity (1441.43±303.08 FAU) and biofilm formation (OD590 0.676±0

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

    SciTech Connect

    Bettin, K.M.; Gerding, D.N.; O'Connor, M.J.; Forstrom, L.A.; Shafer, R.B.

    1984-01-01

    Labeling of live bacteria with gamma emitting radioisotope provides a useful tool for the experimental in vivo tracking of bacteria in various body organs of animals. The authors labeled a serum resistant strain of Pseudomonas aeruginosa (ATCC number27853) with In-111-oxine. P. aeruginosa streaked heavily on ten blood agar plates, was grown overnight, and suspended in 50 ml of saline using sterile cotton swabs. The suspension was sonicated for 3 minutes at 40 watts with a small probe, 500 ..mu..Ci of commercially prepared In-111-oxine added and the bacteria incubated at 37/sup 0/C for 2.5 hours. The labeled bacteria were centrifuged and washed once with saline and resuspended to a final volume of 50 ml in saline. The labeled Pseudomonas, 10/sup 9/-10/sup 10/ cfu/ml, retained 120-190 ..mu..Ci of cell-bound In-111. In vitro studies showed good retention of the In-111 label in saline at 37/sup 0/C (75-85% cell-bound radioactivity at 1 hour) and in canine blood at 37/sup 0/C (30-55% cell-bound radioactivity at 1 hour). The loss of cell-associated radioactivity in blood, with a corresponding decrease in the number of viable organisms, is probably a result of phagocyte-mediated killing of the organisms and subsequent release of the label. The labeled bacteria have been used successfully for sequential imaging in experimental animals to track bacteria injected into blood and the biliary tree.

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

    PubMed

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

    2000-11-01

    To determine the effect of Pseudomonas aeruginosa exotoxin A (P-ExA) on cytokine production, we studied cytokine release induced by heat-killed P. aeruginosa (HKPA) in human whole blood in the presence or absence of P-ExA. P-ExA (0.01-1 microgram ml(-1)) caused a dose-dependent decrease in HKPA-induced production of tumor necrosis factor alpha (TNF), interleukin (IL-) 10, IL-6 and IL-8 (all P<0.05). P-ExA-induced inhibition of IL-10, IL-6 and IL-8 release was not dependent on reduced TNF concentrations, since the relative attenuation of the production of these cytokines was similar in the presence or absence of a neutralizing anti-TNF antibody. The effect of P-ExA on cytokine production may offer a disadvantage to the host with respect to clearance of the infection.

  20. Type IV pili mechanochemically regulate virulence factors in Pseudomonas aeruginosa.

    PubMed

    Persat, Alexandre; Inclan, Yuki F; Engel, Joanne N; Stone, Howard A; Gitai, Zemer

    2015-06-16

    Bacteria have evolved a wide range of sensing systems to appropriately respond to environmental signals. Here we demonstrate that the opportunistic pathogen Pseudomonas aeruginosa detects contact with surfaces on short timescales using the mechanical activity of its type IV pili, a major surface adhesin. This signal transduction mechanism requires attachment of type IV pili to a solid surface, followed by pilus retraction and signal transduction through the Chp chemosensory system, a chemotaxis-like sensory system that regulates cAMP production and transcription of hundreds of genes, including key virulence factors. Like other chemotaxis pathways, pili-mediated surface sensing results in a transient response amplified by a positive feedback that increases type IV pili activity, thereby promoting long-term surface attachment that can stimulate additional virulence and biofilm-inducing pathways. The methyl-accepting chemotaxis protein-like chemosensor PilJ directly interacts with the major pilin subunit PilA. Our results thus support a mechanochemical model where a chemosensory system measures the mechanically induced conformational changes in stretched type IV pili. These findings demonstrate that P. aeruginosa not only uses type IV pili for surface-specific twitching motility, but also as a sensor regulating surface-induced gene expression and pathogenicity.

  1. Reactions of Pseudomonas aeruginosa pyocyanin with reduced glutathione.

    PubMed

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

    2008-01-01

    Pseudomonas aeruginosa is the most common cause of chronic and recurrent lung infections in patients with cystic fibrosis (CF) whose sputa contain copious quantities of P. aeruginosa toxin, pyocyanin. Pyocyanin triggers tissue damage mainly by its redox cycling and induction of reactive oxygen species (ROS). The reactions between reduced glutathione (GSH) and pyocyanin were observed using absorption spectra from spectrophotometry and the reaction products analysed by nuclear magnetic resonance imaging. Pyocyanin reacted with GSH non-enzymatically at 37 degrees C resulting in the production of red-brown products, spectophotometrically visible as a 480 nm maximum absorption peak after 24 h of incubation. The reaction was concentration-dependent on reduced glutathione but not on pyocyanin. Minimizing the accessibility of oxygen to the reaction decreased its rate. The anti-oxidant enzyme catalase circumvented the reaction. Proton-NMR analysis demonstrated the persistence of the original aromatic ring and the methyl-group of pyocyanin in the red-brown products. Anti-oxidant agents having thiol groups produced similar spectophotometrically visible peaks. The presence of a previously unidentified non-enzymatic GSH-dependent metabolic pathway for pyocyanin has thus been identified. The reaction between pyocyanin and GSH is concentration-, time-, and O(2)-dependent. The formation of H(2)O(2) as an intermediate and the thiol group in GSH seem to be important in this reaction. PMID:18797520

  2. Regulation of Pseudomonas aeruginosa chemotaxis by the nitrogen source.

    PubMed Central

    Craven, R; Montie, T C

    1985-01-01

    The regulation of amino acid chemotaxis by nitrogen was investigated in the gram-negative bacterium Pseudomonas aeruginosa. The quantitative capillary tube technique was used to measure chemotactic responses of bacteria to spatial gradients of amino acids and other attractants. Chemotaxis toward serine, arginine, and alpha-aminoisobutyrate was sharply dependent on the form in which nitrogen was presented to the bacteria. Bacteria grown on mineral salts-succinate with potassium nitrate gave responses to amino acids that were 2 to 3 times those of cells grown on ammonium sulfate and 10 to 20 times those of cells grown in mineral salts-succinate with Casamino Acids as the nitrogen source. A combination of ammonium sulfate and glutamate was as effective as Casamino Acids in depressing serine taxis. The threshold concentration for alpha-aminoisobutyrate taxis was consistently lower in nitrate-grown bacteria than in ammonia-grown bacteria. Responsiveness to sodium succinate, however, was not subject to regulation by nitrogen, and glucose chemotaxis was inhibited, rather than enhanced, in nitrate-grown bacteria. These results indicate that chemotaxis of P. aeruginosa toward amino acids is subject to regulation by nitrogen and that this regulation probably is expressed at the level of the chemoreceptors or transducers. PMID:3932326

  3. Identification of Pseudomonas aeruginosa Phenazines that Kill Caenorhabditis elegans

    PubMed Central

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

    2013-01-01

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

  4. [New Virulent Bacteriophages Active against Multiresistant Pseudomonas aeruginosa Strains].

    PubMed

    Balarjishvili, N Sh; Kvachadze, L I; Kutateladze, M I; Meskhi, T Sh; Pataridze, T K; Berishvili, T A; Tevdoradze, E Sh

    2015-01-01

    The sensitivity of 512 newly isolated Pseudomonas aeruginosa clinical strains to six classes of anti-microbial preparations has been studied. Antibiotic-resistant strains were selected and genotyped. Three new virulent bacteriophages of the families Myoviridae and Podoviridae were isolated against these strains. The parameters of the intracellular phage development cycle were established, and the influence of inactivating factors (temperature, pH, and UV exposure) on phage viability was studied. The molecular weight of the phage genome was determined. Phage DNA restriction analysis and polyacrylamide gel electrophoresis in the presence of envelope protein SDS were carried out. The plating efficacy of phages on 28 genetically distant antibiotic-resistant P. aeruginosa strains was studied. It was established that 26 of them were lysed by phages with a high efficacy. The range of antibacterial action of the studied phages and their mixtures on 427 multi-drug-resistant clinical isolates was assessed. It is shown that including these phages in one multicomponent preparation enhanced their lytic activity. PMID:26859962

  5. Glycosylation Substrate Specificity of Pseudomonas aeruginosa 1244 Pilin*S

    PubMed Central

    Horzempa, Joseph; Comer, Jason E.; Davis, Sheila A.; Castric, Peter

    2008-01-01

    The β-carbon of the Pseudomonas aeruginosa 1244 pilin C-terminal Ser is a site of glycosylation. The present study was conducted to determine the pilin structures necessary for glycosylation. It was found that although Thr could be tolerated at the pilin C terminus, the blocking of the Ser carboxyl group with the addition of an Ala prevented glycosylation. Pilin from strain PA103 was not glycosylated by P. aeruginosa 1244, even when the C-terminal residue was converted to Ser. Substituting the disulfide loop region of strain PA103 pilin with that of strain 1244 allowed glycosylation to take place. Neither conversion of 1244 pilin disulfide loop Cys residues to Ala nor the deletion of segments of this structure prevented glycosylation. It was noted that the PA103 pilin disulfide loop environment was electronegative, whereas that of strain 1244 pilin had an overall positive charge. Insertion of a positive charge into the PA103 pilin disulfide loop of a mutant containing Ser at the C terminus allowed glycosylation to take place. Extending the “tail” region of the PA103 mutant pilin containing Ser at its terminus resulted in robust glycosylation. These results suggest that the terminal Ser is the major pilin glycosylation recognition feature and that this residue cannot be substituted at its carboxyl group. Although no other specific recognition features are present, the pilin surface must be compatible with the reaction apparatus for glycosylation to occur. PMID:16286455

  6. Identification of the Pseudomonas aeruginosa 1244 Pilin Glycosylation Site

    PubMed Central

    Comer, Jason E.; Marshall, Mark A.; Blanch, Vincent J.; Deal, Carolyn D.; Castric, Peter

    2002-01-01

    Previous work (P. Castric, F. J. Cassels, and R. W. Carlson, J. Biol. Chem. 276:26479-26485, 2001) has shown the Pseudomonas aeruginosa 1244 pilin glycan to be covalently bound to a serine residue. N-terminal sequencing of pilin fragments produced from endopeptidase treatment and identified by reaction with a glycan-specific monoclonal antibody indicated that the glycan was present between residue 75 and the pilin carboxy terminus. Further sequencing of these peptides revealed that serine residues 75, 81, 84, 105, 106, and 108 were not modified. Conversion of serine 148, but not serine 118, to alanine by site-directed mutagenesis, resulted in loss of the ability to carry out pilin glycosylation when tested in an in vivo system. These results showed the pilin glycan to be attached to residue 148, the carboxy-terminal amino acid. The carboxy-proximal portion of the pilin disulfide loop, which is adjacent to the pilin glycan, was found to be a major linear B-cell epitope, as determined by peptide epitope mapping analysis. Immunization of mice with pure pili produced antibodies that recognized the pilin glycan. These sera also reacted with P. aeruginosa 1244 lipopolysaccharide as measured by Western blotting and enzyme-linked immunosorbent assay. PMID:12010970

  7. A molecular mechanism that stabilizes cooperative secretions in Pseudomonas aeruginosa

    PubMed Central

    Kim, Wook

    2010-01-01

    Summary Bacterial populations frequently act as a collective by secreting a wide range of compounds necessary for cell-cell communication, host colonization and virulence. However, how such behaviors avoid exploitation by spontaneous ‘cheater’ mutants that use but do not contribute to secretions remains unclear. We investigate this question using Pseudomonas aeruginosa swarming, a collective surface motility requiring massive secretions of rhamnolipid biosurfactants. We first show that swarming is immune to the evolution of rhlA− ‘cheaters’. We then demonstrate that P. aeruginosa resists cheating through metabolic prudence: wild-type cells secrete biosurfactants only when the cost of their production and impact on individual fitness is low, therefore preventing non-secreting strains from gaining an evolutionary advantage. Metabolic prudence works because the carbon-rich biosurfactants are only produced when growth is limited by another growth limiting nutrient, the nitrogen source. By genetically manipulating a strain to produce the biosurfactants constitutively we show that swarming becomes cheatable: a non-producing strain rapidly outcompetes and replaces this obligate cooperator. We argue that metabolic prudence, which may first evolve as a direct response to cheating or simply to optimize growth, can explain the maintenance of massive secretions in many bacteria. More generally, prudent regulation is a mechanism to stabilize cooperation. PMID:21166901

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

    PubMed

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

    2014-01-01

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

  9. Attenuation of Pseudomonas aeruginosa virulence by quorum sensing inhibitors

    PubMed Central

    Hentzer, Morten; Wu, Hong; Andersen, Jens Bo; Riedel, Kathrin; Rasmussen, Thomas B.; Bagge, Niels; Kumar, Naresh; Schembri, Mark A.; Song, Zhijun; Kristoffersen, Peter; Manefield, Mike; Costerton, John W.; Molin, Søren; Eberl, Leo; Steinberg, Peter; Kjelleberg, Staffan; Høiby, Niels; Givskov, Michael

    2003-01-01

    Traditional treatment of infectious diseases is based on compounds that kill or inhibit growth of bacteria. A major concern with this approach is the frequent development of resistance to antibiotics. The discovery of communication systems (quorum sensing systems) regulating bacterial virulence has afforded a novel opportunity to control infectious bacteria without interfering with growth. Compounds that can override communication signals have been found in the marine environment. Using Pseudomonas aeruginosa PAO1 as an example of an opportunistic human pathogen, we show that a synthetic derivate of natural furanone compounds can act as a potent antagonist of bacterial quorum sensing. We employed GeneChip® microarray technology to identify furanone target genes and to map the quorum sensing regulon. The transcriptome analysis showed that the furanone drug specifically targeted quorum sensing systems and inhibited virulence factor expression. Application of the drug to P.aeruginosa biofilms increased bacterial susceptibility to tobramycin and SDS. In a mouse pulmonary infection model, the drug inhibited quorum sensing of the infecting bacteria and promoted their clearance by the mouse immune response. PMID:12881415

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

    PubMed

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

    2016-01-01

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

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

    PubMed

    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.

  12. Mechanical destruction of pseudomonas aeruginosa biofilms by ultrasound exposure

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  13. Phage selection restores antibiotic sensitivity in MDR Pseudomonas aeruginosa

    PubMed Central

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

    2016-01-01

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

  14. Magnetic fields suppress Pseudomonas aeruginosa biofilms and enhance ciprofloxacin activity.

    PubMed

    Bandara, H M H N; Nguyen, D; Mogarala, S; Osiñski, M; Smyth, H D C

    2015-01-01

    Due to the refractory nature of pathogenic microbial biofilms, innovative biofilm eradication strategies are constantly being sought. Thus, this study addresses a novel approach to eradicate Pseudomonas aeruginosa biofilms. Magnetic nanoparticles (MNP), ciprofloxacin (Cipro), and magnetic fields were systematically evaluated in vitro for their relative anti-biofilm contributions. Twenty-four-hour biofilms exposed to aerosolized MNPs, Cipro, or a combination of both, were assessed in the presence or absence of magnetic fields (Static one-sided, Static switched, Oscillating, Static + oscillating) using changes in bacterial metabolism, biofilm biomass, and biofilm imaging. The biofilms exposed to magnetic fields alone exhibited significant metabolic and biomass reductions (p < 0.05). When biofilms were treated with a MNP/Cipro combination, the most significant metabolic and biomass reductions were observed when exposed to static switched magnetic fields (p < 0.05). The exposure of P. aeruginosa biofilms to a static switched magnetic field alone, or co-administration with MNP/Cipro/MNP + Cipro appears to be a promising approach to eradicate biofilms of this bacterium.

  15. Characterization of the Polymyxin B Resistome of Pseudomonas aeruginosa

    PubMed Central

    Fernández, Lucía; Álvarez-Ortega, Carolina; Wiegand, Irith; Olivares, Jorge; Kocíncová, Dana; Lam, Joseph S.; Martínez, José Luis

    2013-01-01

    Multidrug resistance in Pseudomonas aeruginosa is increasingly becoming a threat for human health. Indeed, some strains are resistant to almost all currently available antibiotics, leaving very limited choices for antimicrobial therapy. In many such cases, polymyxins are the only available option, although as their utilization increases so does the isolation of resistant strains. In this study, we screened a comprehensive PA14 mutant library to identify genes involved in changes of susceptibility to polymyxin B in P. aeruginosa. Surprisingly, our screening revealed that the polymyxin B resistome of this microorganism is fairly small. Thus, only one resistant mutant and 17 different susceptibility/intrinsic resistance determinants were identified. Among the susceptible mutants, a significant number carried transposon insertions in lipopolysaccharide (LPS)-related genes. LPS analysis revealed that four of these mutants (galU, lptC, wapR, and ssg) had an altered banding profile in SDS-polyacrylamide gels and Western blots, with three of them exhibiting LPS core truncation and lack of O-antigen decoration. Further characterization of these four mutants showed that their increased susceptibility to polymyxin B was partly due to increased basal outer membrane permeability. Additionally, these mutants also lacked the aminoarabinose-substituted lipid A species observed in the wild type upon growth in low magnesium. Overall, our results emphasize the importance of LPS integrity and lipid A modification in resistance to polymyxins in P. aeruginosa, highlighting the relevance of characterizing the genes that affect biosynthesis of cell surface structures in this pathogen to follow the evolution of peptide resistance in the clinic. PMID:23070157

  16. Mucin Promotes Rapid Surface Motility in Pseudomonas aeruginosa

    PubMed Central

    Yeung, Amy T. Y.; Parayno, Alicia; Hancock, Robert E. W.

    2012-01-01

    ABSTRACT An important environmental factor that determines the mode of motility adopted by Pseudomonas aeruginosa is the viscosity of the medium, often provided by adjusting agar concentrations in vitro. However, the viscous gel-like property of the mucus layer that overlays epithelial surfaces is largely due to the glycoprotein mucin. P. aeruginosa is known to swim within 0.3% (wt/vol) agar and swarm on the surface at 0.5% (wt/vol) agar with amino acids as a weak nitrogen source. When physiological concentrations or as little as 0.05% (wt/vol) mucin was added to the swimming agar, in addition to swimming, P. aeruginosa was observed to undergo highly accelerated motility on the surface of the agar. The surface motility colonies in the presence of mucin appeared to be circular, with a bright green center surrounded by a thicker white edge. While intact flagella were required for the surface motility in the presence of mucin, type IV pili and rhamnolipid production were not. Replacement of mucin with other wetting agents indicated that the lubricant properties of mucin might contribute to the surface motility. Based on studies with mutants, the quorum-sensing systems (las and rhl) and the orphan autoinducer receptor QscR played important roles in this form of surface motility. Transcriptional analysis of cells taken from the motility zone revealed the upregulation of genes involved in virulence and resistance. Based on these results, we suggest that mucin may be promoting a new or highly modified form of surface motility, which we propose should be termed “surfing.” PMID:22550036

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

    PubMed Central

    Goli, Hamid Reza; Nahaei, Mohammad Reza; Ahangarzadeh Rezaee, Mohammad; Hasani, Alka; Samadi Kafil, Hossein; Aghazadeh, Mohammad

    2016-01-01

    Background and Objectives: The prevalence of multidrug resistant Pseudomonas aeruginosa is the main reason of new drugs resurgence such as colistin. The main objectives of this study were to determine the antibiotic resistance pattern and the rate of colistin resistance along with its correlation with overexpression of MexAB-OprM and MexXY-OprM efflux pumps among P. aeruginosa isolates. Materials and Methods: Hundred clinical isolates were collected from 100 patients during 6 months in 2014. Susceptibility to the eight antibiotics was investigated using Kirby-Bauer and agar dilution methods. The Quantitative Real-time PCR was used to determine the expression levels of efflux genes. Results: Resistance rates to various antibiotics were as follows: ticarcillin (73%), ciprofloxacin (65%), aztreonam (60%), ceftazidime (55%), gentamicin (55%), imipenem (49%), piperacillin/tazobactam (34%) and colistin (2%). In disk diffusion method, only two isolates were non susceptible to colistin, however in agar dilution method the two isolates were confirmed as resistant and two others were intermediate resistant. Sixty eight (68%) isolates were multi-drug resistant and 10 isolates were susceptible to all tested antibiotics. Both colistin resistant isolates showed overexpression of both efflux pumps, but two intermediate resistant isolates exhibited reduction of efflux genes expression. Conclusions: Emergence of colistin resistance is increasing in P. aeruginosa indicating great challenge in the treatment of infections caused by MDR strains of this organism in Iran. ParRS may promote either induced or constitutive resistance to colistin through the activation of distinct mechanisms such as MDR efflux pumps, and LPS modification. PMID:27092226

  18. [Virulence factors in Pseudomonas aeruginosa: mechanisms and modes of regulation].

    PubMed

    Ben Haj Khalifa, Anis; Moissenet, Didier; Vu Thien, Hoang; Khedher, Mohamed

    2011-01-01

    Pseudomonas aeruginosa is a bacterium responsible for severe nosocomial infections, life-threatening infections in immunocompromised persons, and chronic infections in cystic fibrosis patients. The bacterium's virulence depends on a large number of cell-associated and extracellular factors. The virulence factors play an important pathological role in the colonization, the survival of the bacteria and the invasion of tissues. There are two types of virulence factors: (1) factors involved in the acute infection: these factors are either on the surface of P. aeruginosa, either secreted. The pili allow adherence to the epithelium. The exoenzyme S and other adhesins reinforce the adherence to epithelial cells. The exotoxin A is responsible of tissue necrosis. Phospholipase C is a thermolabile haemolysin. The pathogenic role of exoenzyme S is attributable to the disruption of normal cytoskeletal organization, the destruction of immunoglobulin G and A, leads to depolymerization of actin filaments and contributes to the resistance to macrophages. P. aeruginosa produces at least four proteases causing bleeding and tissue necrosis; (2) factors involved in the chronic infection: siderophores (pyoverdin and pyochelin), allow the bacteria to multiply in the absence of ferrous ions. The strains isolated from patients with cystic fibrosis have a pseudocapsule of alginate that protects the bacterium from phagocytosis, dehydration and antibiotics. Moreover, it improves adherence to epithelial cells forming a biofilm. Two different types of regulation systems control the expression of the majority of these virulence factors: the two-component transcriptional regulatory system and the quorum sensing system. These two mechanisms are necessary to the survival and the proliferation of this microorganism in the host. PMID:21896403

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Epidemiology and Ecology of Opportunistic Premise Plumbing Pathogens: Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa

    EPA Science Inventory

    BACKGROUND: Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa are opportunistic premise plumbing pathogens (OPPPs) that persist and grow in household plumbing, habitats they share with humans. Infections caused by these OPPPs involve individuals with preexis...

  1. Lichen secondary metabolite evernic acid as potential quorum sensing inhibitor against Pseudomonas aeruginosa.

    PubMed

    Gökalsın, Barış; Sesal, Nüzhet Cenk

    2016-09-01

    Cystic Fibrosis is a genetic disease and it affects the respiratory and digestive systems. Pseudomonas aeruginosa infections in Cystic Fibrosis are presented as the main cause for high mortality and morbidity rates. Pseudomonas aeruginosa populations can regulate their virulence gene expressions via the bacterial communication system: quorum sensing. Inhibition of quorum sensing by employing quorum sensing inhibitors can leave the bacteria vulnerable. Therefore, determining natural sources to obtain potential quorum sensing inhibitors is essential. Lichens have ethnobotanical value for their medicinal properties and it is possible that their secondary metabolites have quorum sensing inhibitor properties. This study aims to investigate an alternative treatment approach by utilizing lichen secondary metabolite evernic acid to reduce the expressions of Pseudomonas aeruginosa virulence factors by inhibiting quorum sensing. For this purpose, fluorescent monitor strains were utilized for quorum sensing inhibitor screens and quantitative reverse-transcriptase PCR analyses were conducted for comparison. Results indicate that evernic acid is capable of inhibiting Pseudomonas aeruginosa quorum sensing systems.

  2. Variations in properties of L-forms of Pseudomonas aeruginosa.

    PubMed Central

    Bertolani, R; Elberg, S S; Ralston, D

    1975-01-01

    In a study of the pathogenic potentials of Pseudomonas L-forms, three unstable L-forms were derived by carbenicillin inductionfrom a mouse virulent strain of Pseudomonas aeruginosa, Rosenthal 180. One L-form, induced on a sucrose-stabilized medium, grew more slowly and differed in a number of properties from two other L-forms induced on a medium supported with polyvinylpyrilidone. After adaptation to a common liquid medium, the three L-forms differed with respect to colonial shape on solid medium, growth rate, certain biochemical properties, antibiotic sensitivities and antigenic surface, and virulence for mice. The L-form may revert in vitro to a serotype different from that of the parent culture. The revertant may acquire new antibiotic resistances and sensitivities in the absence of previous exposure to the drugs and enhanced resistance to the L-inducing agent. The three L-forms showed a characteristically lower, but wide, range of virulence than did the parental form. Though death of mice was accompanied by reversion of the L-forms in vivo to the bacterial form, reversion in vivo was not necessary for virulence of L-forms. Modification of residual cell wall antigens accompanied the induction of each L-form as determined by type-specific antisera. Images PMID:803921

  3. Links between Anr and Quorum Sensing in Pseudomonas aeruginosa Biofilms

    PubMed Central

    Hammond, John H.; Dolben, Emily F.; Smith, T. Jarrod; Bhuju, Sabin

    2015-01-01

    ABSTRACT In Pseudomonas aeruginosa, the transcription factor Anr controls the cellular response to low oxygen or anoxia. Anr activity is high in oxygen-limited environments, including biofilms and populations associated with chronic infections, and Anr is necessary for persistence in a model of pulmonary infection. In this study, we characterized the Anr regulon in biofilm-grown cells at 1% oxygen in the laboratory strain PAO1 and in a quorum sensing (QS)-deficient clinical isolate, J215. As expected, transcripts related to denitrification, arginine fermentation, high-affinity cytochrome oxidases, and CupA fimbriae were lower in the Δanr derivatives. In addition, we observed that transcripts associated with quorum sensing regulation, iron acquisition and storage, type VI secretion, and the catabolism of aromatic compounds were also differentially expressed in the Δanr strains. Prior reports have shown that quorum sensing-defective mutants have higher levels of denitrification, and we found that multiple Anr-regulated processes, including denitrification, were strongly inversely proportional to quorum sensing in both transcriptional and protein-based assays. We also found that in LasR-defective strains but not their LasR-intact counterparts, Anr regulated the production of the 4-hydroxy-2-alkylquinolines, which play roles in quorum sensing and interspecies interactions. These data show that Anr was required for the expression of important metabolic pathways in low-oxygen biofilms, and they reveal an expanded and compensatory role for Anr in the regulation of virulence-related genes in quorum sensing mutants, such as those commonly isolated from infections. IMPORTANCE Pseudomonas aeruginosa causes acute ocular, soft tissue, and pulmonary infections, as well as chronic infections in the airways of cystic fibrosis patients. P. aeruginosa uses quorum sensing (QS) to regulate virulence, but mutations in the gene encoding the master regulator of QS, lasR, are frequently

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

    PubMed

    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

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  7. Genome Sequence of Pseudomonas aeruginosa Strain LCT-PA41, with Changed Metabolism after Space Flight.

    PubMed

    Liu, Chao; Hu, Juan; Fang, Xiangqun; Zhang, Duchao; Chang, De; Wang, Junfeng; Li, Tianzhi; Guo, Yinhua; Dai, Wenkui; Liu, Changting

    2014-01-09

    To explore the effects of space flight on microorganisms, Pseudomonas aeruginosa ATCC 27853 was sent into orbit for 398 h on the spacecraft ShenZhou VIII. Here, we present the draft genome sequence of the P. aeruginosa strain LCT-PA41, determined after space flight.

  8. Draft Genome Sequence of Pseudomonas aeruginosa Strain RB, a Bacterium Capable of Synthesizing Cadmium Selenide Nanoparticles.

    PubMed

    Ayano, Hiroyuki; Kuroda, Masashi; Soda, Satoshi; Ike, Michihiko

    2014-01-01

    Pseudomonas aeruginosa strain RB is a bacterium capable of synthesizing cadmium selenide (CdSe) nanoparticles and was isolated from a soil sample. Here, we present the draft genome sequence of P. aeruginosa strain RB. To the best of our knowledge, this is the first report of a draft genome of a CdSe-synthesizing bacterium.

  9. The Pseudomonas aeruginosa Pathogenicity Island PAPI-1 is transferred via a novel Type IV pilus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas aeruginosa is a major cause of nosocomial infections, particularly in immunocompromised patients or in individuals with cystic fibrosis. The notable ability of P. aeruginosa to inhabit a broad range of environments including humans is in part due to its large and diverse genomic repertoi...

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

    PubMed Central

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

    2016-01-01

    Pseudomonas aeruginosa is a Gram-negative bacterium of clinical significance. Although the genome of PAO1, a prototype strain of P. aeruginosa, has been extensively studied, approximately one-third of the functional genome remains unknown. With the emergence of antibiotic-resistant strains of P. aeruginosa, there is an urgent need to develop novel antibiotic and anti-virulence strategies, which may be facilitated by an approach that explores P. aeruginosa gene function in systems-level models. Here, we present a genome-wide functional network of P. aeruginosa genes, PseudomonasNet, which covers 98% of the coding genome, and a companion web server to generate functional hypotheses using various network-search algorithms. We demonstrate that PseudomonasNet-assisted predictions can effectively identify novel genes involved in virulence and antibiotic resistance. Moreover, an antibiotic-resistance network based on PseudomonasNet reveals that P. aeruginosa has common modular genetic organisations that confer increased or decreased resistance to diverse antibiotics, which accounts for the pervasiveness of cross-resistance across multiple drugs. The same network also suggests that P. aeruginosa has developed mechanism of trade-off in resistance across drugs by altering genetic interactions. Taken together, these results clearly demonstrate the usefulness of a genome-scale functional network to investigate pathogenic systems in P. aeruginosa. PMID:27194047

  11. Pseudomonas aeruginosa septic arthritis of knee after intra-articular ozone injection.

    PubMed

    Seyman, Derya; Ozen, Nevgun Sepin; Inan, Dilara; Ongut, Gozde; Ogunc, Dilara

    2012-07-01

    We describe a case of septic arthritis caused by Pseudomonas aeruginosa in an immunocompetent patient following intra-articular ozone injection into the knee. To the best of our knowledge, and after considering the current literature,we believe this case is unique as no other reports of septic arthritis caused by P. aeruginosa following intra-articular ozone injection has been made.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  13. Genome Sequence of Pseudomonas aeruginosa Strain LCT-PA41, with Changed Metabolism after Space Flight

    PubMed Central

    Liu, Chao; Hu, Juan; Fang, Xiangqun; Zhang, Duchao; Chang, De; Wang, Junfeng; Li, Tianzhi; Guo, Yinhua; Dai, Wenkui

    2014-01-01

    To explore the effects of space flight on microorganisms, Pseudomonas aeruginosa ATCC 27853 was sent into orbit for 398 h on the spacecraft ShenZhou VIII. Here, we present the draft genome sequence of the P. aeruginosa strain LCT-PA41, determined after space flight. PMID:24407638

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

    PubMed

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

    2016-05-19

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

  15. Role of the Pseudomonas quinolone signal (PQS) in sensitising Pseudomonas aeruginosa to UVA radiation.

    PubMed

    Pezzoni, Magdalena; Meichtry, Martín; Pizarro, Ramón A; Costa, Cristina S

    2015-01-01

    One of the main stress factors that bacteria face in the environment is solar ultraviolet-A (UVA) radiation, which leads to lethal effects through oxidative damage. The aim of this work was to investigate the role of 2-heptyl-3-hydroxi-4-quinolone (the Pseudomonas quinolone signal or PQS) in the response of Pseudomonas aeruginosa to UVA radiation. PQS is an intercellular quorum sensing signal associated to membrane vesicles which, among other functions, regulates genes related to iron acquisition, forms stable complexes with iron and participates in oxidative phenomena. UVA exposure of the wild-type PAO1 strain and a pqsA mutant unable to produce PQS revealed a sensitising role for this signal. Research into the mechanism involved in this phenomenon revealed that catalase, an essential factor in the UVA defence, is not related to PQS-mediated UVA sensitivity. Absorption of UVA by PQS produced its own photo-degradation, oxidation of the probe 2',7'- dichlorodihydrofluorescein and generation of singlet oxygen and superoxide anion, suggesting that this signal could be acting as an endogenous photosensitiser. The results presented in this study could explain the high sensitivity to UVA of P. aeruginosa when compared to enteric bacteria. PMID:25535873

  16. Voltammetric profiling of redox-active metabolites expressed by Pseudomonas aeruginosa for diagnostic purposes.

    PubMed

    Seviour, T; Doyle, L E; Lauw, S J L; Hinks, J; Rice, S A; Nesatyy, V J; Webster, R D; Kjelleberg, S; Marsili, E

    2015-03-01

    In Pseudomonas aeruginosa, chemical deconvolution of the pyocyanin voltammetric signal allows its expression to be observed simultaneously with the quorum sensing molecule Pseudomonas quinolone signal (PQS). Such analysis has revealed that PQS might protect pyocyanin from self-oxidation, but also exert a pro-oxidative effect on pyocyanin under oxidative conditions to produce additional redox metabolites. PMID:25650009

  17. Hydrocarbon assimilation and biosurfactant production in Pseudomonas aeruginosa mutants

    SciTech Connect

    Koch, A.K.; Fiechter, A.; Reiser, J. ); Kaeppeli, O. )

    1991-07-01

    The authors isolated transposon Tn5-GM-induced mutants of Pseudomonas aeruginosa PG201 that were unable to grow in minimal media containing hexadecane as a carbon source. Some of these mutants lacked extracellular rhamnolipids, as shown by measuring the surface and interfacial tensions of the cell culture supernatants. Furthermore, the concentrated culture media of the mutant strains were tested for the presence of rhamnolipids by thin-layer chromatography and for rhamnolipid activities, including hemolysis and growth inhibition of Bacillus subtilis. Mutant 65E12 was unable to produce extracellular rhamnolipids under any of the inhibition of Bacillus subtilis. Mutant 65E12 was unable to produce extracellular rhamnolipids under any of the conditions tested, lacked the capacity to take up {sup 14}C-labeled hexadecane, and did not grow in media containing individual alkanes with chain lengths ranging from C{sub 12} to C{sub 19}. However, growth on these alkanes and uptake of ({sup 14}C)hexadecane were restored when small amounts of purified rhamnolipids were added to the cultures. Mutant 59C7 was unable to grow in media containing hexadecane, nor was it able to take up ({sup 14}C)hexadecane uptake. The addition of small amounts of rhamnolipids restored on alkanes and ({sup 14}C)hexadecane uptake. In glucose-containing media, however, mutant 59C7 produced rhamnolipids at levels about twice as high as those of the wild-type strain. These results show that rhamnolipids play a major role in hexadecane uptake and utilization by P.aeruginosa.

  18. Ciprofloxacin susceptibility of Pseudomonas aeruginosa isolates from keratitis

    PubMed Central

    Lomholt, J A; Kilian, M

    2003-01-01

    Aim: To examine the ciprofloxacin susceptibility of 106 Pseudomonas aeruginosa eye isolates from the United Kingdom, Denmark, India, the United States, and Australia, and to determine the molecular mechanisms of resistance. Methods: Ciprofloxacin susceptibility was tested by an agar dilution method; genomic DNA corresponding to the quinolone target genes gyrA and parC, and the regulatory genes mexR and nfxB controlling drug efflux systems, was amplified by PCR and sequenced; multilocus enzyme electrophoresis was performed to examine the genetic relation among resistant strains. Results: Three out of 90 keratitis isolates (3.3%), one from the United Kingdom and two from India, exhibited MIC values of 16 mg/l or 32 mg/l. The UK isolate had a mutation in gyrA (Thr83Ile), whereas the two Indian isolates showed mutations in both gyrA (Thr83Ile) and parC (Ser87Leu). The remaining isolates from keratitis, endophthalmitis, contact lens associated red eye (CLARE), and contact lens storage cases showed MIC values below 1 mg/l. Several allelic forms of gyrA and a single variation in the mexR gene product were detected in 10 ciprofloxacin susceptible strains. Conclusions: The vast majority of eye isolates of P aeruginosa from European countries are fully susceptible to ciprofloxacin and the concentration of ciprofloxacin eye drops used for local treatment (3000 mg/l) exceeds MIC values for strains recorded as resistant. Mutations in more than one target gene were associated with higher MIC values. PMID:14507757

  19. Phosphorylcholine Phosphatase: A Peculiar Enzyme of Pseudomonas aeruginosa

    PubMed Central

    Domenech, Carlos Eduardo; Otero, Lisandro Horacio; Beassoni, Paola Rita; Lisa, Angela Teresita

    2011-01-01

    Pseudomonas aeruginosa synthesizes phosphorylcholine phosphatase (PchP) when grown on choline, betaine, dimethylglycine or carnitine. In the presence of Mg2+ or Zn2+, PchP catalyzes the hydrolysis of p-nitrophenylphosphate (p-NPP) or phosphorylcholine (Pcho). The regulation of pchP gene expression is under the control of GbdR and NtrC; dimethylglycine is likely the metabolite directly involved in the induction of PchP. Therefore, the regulation of choline metabolism and consequently PchP synthesis may reflect an adaptive response of P. aeruginosa to environmental conditions. Bioinformatic and biochemistry studies shown that PchP contains two sites for alkylammonium compounds (AACs): one in the catalytic site near the metal ion-phosphoester pocket, and another in an inhibitory site responsible for the binding of the alkylammonium moiety. Both sites could be close to each other and interact through the residues 42E, 43E and 82YYY84. Zn2+ is better activator than Mg2+ at pH 5.0 and it is more effective at alleviating the inhibition produced by the entry of Pcho or different AACs in the inhibitory site. We postulate that Zn2+ induces at pH 5.0 a conformational change in the active center that is communicated to the inhibitory site, producing a compact or closed structure. However, at pH 7.4, this effect is not observed because to the hydrolysis of the [Zn2+L2−1L20(H2O)2] complex, which causes a change from octahedral to tetrahedral in the metal coordination geometry. This enzyme is also present in P. fluorescens, P. putida, P. syringae, and other organisms. We have recently crystallized PchP and solved its structure. PMID:21915373

  20. Pyocyanin Production by Pseudomonas aeruginosa Confers Resistance to Ionic Silver

    PubMed Central

    Merrett, Neil D.

    2014-01-01

    Silver in its ionic form (Ag+), but not the bulk metal (Ag0), is toxic to microbial life forms and has been used for many years in the treatment of wound infections. The prevalence of bacterial resistance to silver is considered low due to the nonspecific nature of its toxicity. However, the recent increased use of silver as an antimicrobial agent for medical, consumer, and industrial products has raised concern that widespread silver resistance may emerge. Pseudomonas aeruginosa is a common pathogen that produces pyocyanin, a redox toxin and a reductant for molecular oxygen and ferric (Fe3+) ions. The objective of this study was to determine whether pyocyanin reduces Ag+ to Ag0, which may contribute to silver resistance due to lower bioavailability of the cation. Using surface plasmon resonance spectroscopy and scanning electron microscopy, pyocyanin was confirmed to be a reductant for Ag+, forming Ag0 nanoparticles and reducing the bioavailability of free Ag+ by >95% within minutes. Similarly, a pyocyanin-producing strain of P. aeruginosa (PA14) reduced Ag+ but not a pyocyanin-deficient (ΔphzM) strain of the bacterium. Challenge of each strain with Ag+ (as AgNO3) gave MICs of 20 and 5 μg/ml for the PA14 and ΔphzM strains, respectively. Removal of pyocyanin from the medium strain PA14 was grown in or its addition to the medium that ΔphzM mutant was grown in gave MICs of 5 and 20 μg/ml, respectively. Clinical isolates demonstrated similar pyocyanin-dependent resistance to Ag+. We conclude that pseudomonal silver resistance exists independently of previously recognized intracellular mechanisms and may be more prevalent than previously considered. PMID:25001302

  1. Fructooligosacharides Reduce Pseudomonas aeruginosa PAO1 Pathogenicity through Distinct Mechanisms

    PubMed Central

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

    2014-01-01

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

  2. A re-examination of twitching motility in Pseudomonas aeruginosa.

    PubMed

    Semmler, A B; Whitchurch, C B; Mattick, J S

    1999-10-01

    Twitching motility is a form of solid surface translocation which occurs in a wide range of bacteria and which is dependent on the presence of functional type IV fimbriae or pili. A detailed examination of twitching motility in Pseudomonas aeruginosa under optimal conditions in vitro was carried out. Under these conditions (at the smooth surface formed between semi-solid growth media and plastic or glass surfaces) twitching motility is extremely rapid, leading to an overall radial rate of colony expansion of 0.6 mm h(-1) or greater. The zones of colony expansion due to twitching motility are very thin and are best visualized by staining. These zones exhibit concentric rings in which there is a high density of microcolonies, which may reflect periods of expansion and consolidation/cell division. Video microscopic analysis showed that twitching motility involves the initial formation of large projections or rafts of aggregated cells which move away from the colony edge. Behind the rafts, individual cells move rapidly up and down trails which thin and branch out, ultimately forming a fine lattice-like network of cells. The bacteria in the lattice network then appear to settle and divide to fill out the colonized space. Our observations redefine twitching motility as a rapid, highly organized mechanism of bacterial translocation by which P. aeruginosa can disperse itself over large areas to colonize new territories. It is also now clear, both morphologically and genetically, that twitching motility and social gliding motility, such as occurs in Myxococcus xanthus, are essentially the same process.

  3. Combined treatment of Pseudomonas aeruginosa biofilms with bacteriophages and chlorine.

    PubMed

    Zhang, Yanyan; Hu, Zhiqiang

    2013-01-01

    Bacterial biofilms are a growing concern in a broad range of areas. In this study, a mixture of RNA bacteriophages isolated from municipal wastewater was used to control and remove biofilms. At the concentrations of 400 and 4 × 10(7) PFU/mL, the phages inhibited Pseudomonas aeruginosa biofilm formation by 45 ± 15% and 73 ± 8%, respectively. At the concentrations of 6,000 and 6 × 10(7) PFU/mL, the phages removed 45 ± 9% and 75 ± 5% of pre-existing P. aeruginosa biofilms, respectively. Chlorine reduced biofilm growth by 86 ± 3% at the concentration of 210 mg/L, but it did not remove pre-existing biofilms. However, a combination of phages (3 × 10(7) PFU/mL) and chlorine at this concentration reduced biofilm growth by 94 ± 2% and removed 88 ± 6% of existing biofilms. In a continuous flow system with continued biofilm growth, a combination of phages (a one-time treatment at the concentration of 1.9 × 10(8) PFU/mL for 1 h first) with chlorine removed 97 ± 1% of biofilms after Day 5 while phage and chlorine treatment alone removed 89 ± 1% and 40 ± 5%, respectively. For existing biofilms, a combined use of a lower phage concentration (3.8 × 10(5) PFU/mL) and chlorination with a shorter time duration (12 h) followed by continuous water flushing removed 96 ± 1% of biofilms in less than 2 days. Laser scanning confocal microscopy supplemented with electron microscopy indicated that the combination treatment resulted in biofilms with lowest cell density and viability. These results suggest that the combination treatment of phages and chlorine is a promising method to control and remove bacterial biofilms from various surfaces.

  4. Characterization of Pseudomonas aeruginosa chitinase, a gradually secreted protein.

    PubMed

    Folders, J; Algra, J; Roelofs, M S; van Loon, L C; Tommassen, J; Bitter, W

    2001-12-01

    The gram-negative bacterium Pseudomonas aeruginosa secretes many proteins into its extracellular environment via the type I, II, and III secretion systems. In this study, a gene, chiC, coding for an extracellular chitinolytic enzyme, was identified. The chiC gene encodes a polypeptide of 483 amino acid residues, without a typical N-terminal signal sequence. Nevertheless, an N-terminal segment of 11 residues was found to be cleaved off in the secreted protein. The protein shows sequence similarity to the secreted chitinases ChiC of Serratia marcescens, ChiA of Vibrio harveyi, and ChiD of Bacillus circulans and consists of an activity domain and a chitin-binding domain, which are separated by a fibronectin type III domain. ChiC was able to bind and degrade colloidal chitin and was active on the artificial substrates carboxymethyl-chitin-Remazol Brilliant Violet and p-nitrophenyl-beta-D-N,N',N"-triacetylchitotriose, but not on p-nitrophenyl-beta-D-N-acetylglucosamine, indicating that it is an endochitinase. Expression of the chiC gene appears to be regulated by the quorum-sensing system of P. aeruginosa, since this gene was not expressed in a lasIR vsmI mutant. After overnight growth, the majority of the ChiC produced was found intracellularly, whereas only small amounts were detected in the culture medium. However, after several days, the cellular pool of ChiC was largely depleted, and the protein was found in the culture medium. This release could not be ascribed to cell lysis. Since ChiC did not appear to be secreted via any of the known secretion systems, a novel secretion pathway seems to be involved.

  5. Protein Network of the Pseudomonas aeruginosa Denitrification Apparatus

    PubMed Central

    Borrero-de Acuña, José Manuel; Rohde, Manfred; Wissing, Josef; Jänsch, Lothar; Schobert, Max; Molinari, Gabriella; Timmis, Kenneth N.

    2016-01-01

    ABSTRACT Oxidative phosphorylation using multiple-component, membrane-associated protein complexes is the most effective way for a cell to generate energy. Here, we systematically investigated the multiple protein-protein interactions of the denitrification apparatus of the pathogenic bacterium Pseudomonas aeruginosa. During denitrification, nitrate (Nar), nitrite (Nir), nitric oxide (Nor), and nitrous oxide (Nos) reductases catalyze the reaction cascade of NO3− → NO2− → NO → N2O → N2. Genetic experiments suggested that the nitric oxide reductase NorBC and the regulatory protein NosR are the nucleus of the denitrification protein network. We utilized membrane interactomics in combination with electron microscopy colocalization studies to elucidate the corresponding protein-protein interactions. The integral membrane proteins NorC, NorB, and NosR form the core assembly platform that binds the nitrate reductase NarGHI and the periplasmic nitrite reductase NirS via its maturation factor NirF. The periplasmic nitrous oxide reductase NosZ is linked via NosR. The nitrate transporter NarK2, the nitrate regulatory system NarXL, various nitrite reductase maturation proteins, NirEJMNQ, and the Nos assembly lipoproteins NosFL were also found to be attached. A number of proteins associated with energy generation, including electron-donating dehydrogenases, the complete ATP synthase, almost all enzymes of the tricarboxylic acid (TCA) cycle, and the Sec system of protein transport, among many other proteins, were found to interact with the denitrification proteins. This deduced nitrate respirasome is presumably only one part of an extensive cytoplasmic membrane-anchored protein network connecting cytoplasmic, inner membrane, and periplasmic proteins to mediate key activities occurring at the barrier/interface between the cytoplasm and the external environment. IMPORTANCE The processes of cellular energy generation are catalyzed by large multiprotein enzyme complexes

  6. Impact of glycerol-3-phosphate dehydrogenase on virulence factor production by Pseudomonas aeruginosa.

    PubMed

    Daniels, Jonathan B; Scoffield, Jessica; Woolnough, Jessica L; Silo-Suh, Laura

    2014-12-01

    Pseudomonas aeruginosa establishes life-long chronic infections in the cystic fibrosis (CF) lung by utilizing various adaptation strategies. Some of these strategies include altering metabolic pathways to utilize readily available nutrients present in the host environment. The airway sputum contains various host-derived nutrients that can be utilized by P. aeruginosa, including phosphatidylcholine, a major component of lung surfactant. Pseudomonas aeruginosa can degrade phosphatidylcholine to glycerol and fatty acids to increase the availability of usable carbon sources in the CF lung. In this study, we show that some CF-adapted P. aeruginosa isolates utilize glycerol more efficiently as a carbon source than nonadapted isolates. Furthermore, a mutation in a gene required for glycerol utilization impacts the production of several virulence factors in both acute and chronic isolates of P. aeruginosa. Taken together, the results suggest that interference with this metabolic pathway may have potential therapeutic benefits. PMID:25409940

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

    SciTech Connect

    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.

  8. Transcription antitermination regulation of the Pseudomonas aeruginosa amidase operon.

    PubMed Central

    Wilson, S A; Wachira, S J; Norman, R A; Pearl, L H; Drew, R E

    1996-01-01

    In vivo titration experiments have demonstrated a direct interaction between the Pseudomonas aeruginosa transcription antiterminator, AmiR, and the mRNA leader sequence of the amidase operon. A region of 39 nucleotides has been identified which is sufficient to partially titrate out the AmiR available for antitermination. Site-directed mutagenesis has shown that the leader open reading frame has no role in the antitermination reaction, and has identified two critical elements at the 5' and 3' ends of the proposed AmiR binding site which are independently essential for antitermination. A T7 promoter/RNA polymerase-driven system shows AmiR-mediated antitermination, demonstrating a lack of promoter/polymerase specificity. Using the operon negative regulator, AmiC, immobilized on a solid support and gel filtration chromatography, an AmiC-AmiR complex has been identified and isolated. Complex stability and molecular weight assayed by gel filtration alter depending on the type of amide bound to AmiC. AmiC-AmiR-anti-inducer is a stable dimer-dimer complex and the addition of the inducer, acetamide, causes a conformational change which alters the complex stability and either this new configuration or dissociated AmiR interacts with the leader mRNA to cause antitermination. Images PMID:8918468

  9. Transcriptome Profiling of Antimicrobial Resistance in Pseudomonas aeruginosa.

    PubMed

    Khaledi, Ariane; Schniederjans, Monika; Pohl, Sarah; Rainer, Roman; Bodenhofer, Ulrich; Xia, Boyang; Klawonn, Frank; Bruchmann, Sebastian; Preusse, Matthias; Eckweiler, Denitsa; Dötsch, Andreas; Häussler, Susanne

    2016-08-01

    Emerging resistance to antimicrobials and the lack of new antibiotic drug candidates underscore the need for optimization of current diagnostics and therapies to diminish the evolution and spread of multidrug resistance. As the antibiotic resistance status of a bacterial pathogen is defined by its genome, resistance profiling by applying next-generation sequencing (NGS) technologies may in the future accomplish pathogen identification, prompt initiation of targeted individualized treatment, and the implementation of optimized infection control measures. In this study, qualitative RNA sequencing was used to identify key genetic determinants of antibiotic resistance in 135 clinical Pseudomonas aeruginosa isolates from diverse geographic and infection site origins. By applying transcriptome-wide association studies, adaptive variations associated with resistance to the antibiotic classes fluoroquinolones, aminoglycosides, and β-lactams were identified. Besides potential novel biomarkers with a direct correlation to resistance, global patterns of phenotype-associated gene expression and sequence variations were identified by predictive machine learning approaches. Our research serves to establish genotype-based molecular diagnostic tools for the identification of the current resistance profiles of bacterial pathogens and paves the way for faster diagnostics for more efficient, targeted treatment strategies to also mitigate the future potential for resistance evolution. PMID:27216077

  10. Electrical conductivity measurements of bacterial nanowires from Pseudomonas aeruginosa

    NASA Astrophysics Data System (ADS)

    Maruthupandy, Muthusamy; Anand, Muthusamy; Maduraiveeran, Govindhan; Sait Hameedha Beevi, Akbar; Jeeva Priya, Radhakrishnan

    2015-12-01

    The extracellular appendages of bacteria (flagella) that transfer electrons to electrodes are called bacterial nanowires. This study focuses on the isolation and separation of nanowires that are attached via Pseudomonas aeruginosa bacterial culture. The size and roughness of separated nanowires were measured using transmission electron microscopy (TEM) and atomic force microscopy (AFM), respectively. The obtained bacterial nanowires indicated a clear image of bacterial nanowires measuring 16 nm in diameter. The formation of bacterial nanowires was confirmed by microscopic studies (AFM and TEM) and the conductivity nature of bacterial nanowire was investigated by electrochemical techniques. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which are nondestructive voltammetry techniques, suggest that bacterial nanowires could be the source of electrons—which may be used in various applications, for example, microbial fuel cells, biosensors, organic solar cells, and bioelectronic devices. Routine analysis of electron transfer between bacterial nanowires and the electrode was performed, providing insight into the extracellular electron transfer (EET) to the electrode. CV revealed the catalytic electron transferability of bacterial nanowires and electrodes and showed excellent redox activities. CV and EIS studies showed that bacterial nanowires can charge the surface by producing and storing sufficient electrons, behave as a capacitor, and have features consistent with EET. Finally, electrochemical studies confirmed the development of bacterial nanowires with EET. This study suggests that bacterial nanowires can be used to fabricate biomolecular sensors and nanoelectronic devices.

  11. Functional analysis of the Pseudomonas aeruginosa autoinducer PAI.

    PubMed Central

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

    1996-01-01

    A series of structural analogs of the Pseudomonas aeruginosa autoinducer [PAI, N-3-oxo-dodecanoyl homoserine lactone] were obtained and tested for their ability to act as autoinducers in stimulating the expression of the gene for elastase (lasB) by measuring beta-galactosidase production from a lasB-lacZ gene fusion in the presence of the transcriptional activator LasR. The data suggest that the length of the acyl side chain of the autoinducer molecule is the most critical factor for activity. Replacement of the ring O by S in the homoserine lactone moiety can be tolerated. Tritium-labelled PAI ([3H]PAI) was synthesized and used to demonstrate the association of [3H]PAI with cells overexpressing LasR. The PAI analogs were also tested for their ability to compete with [3H]PAI for binding of LasR. Results from the competition assays suggest that once again the length of the acyl side chain appears to be crucial for antagonist activity. The presence of the 3-oxo moiety also plays a significant role in binding since analogs which lacked this moiety were much less effective in blocking binding of [3H]PAI. All analogs demonstrating competition with PAI in binding to LasR also exhibited the ability to activate lasB expression, suggesting that they are functional analogs of PAI. PMID:8830697

  12. Ginger extract inhibits biofilm formation by Pseudomonas aeruginosa PA14.

    PubMed

    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

  13. Prevention of Pseudomonas aeruginosa adhesion by electric currents.

    PubMed

    Shim, Soojin; Hong, Seok Hoon; Tak, Yongsug; Yoon, Jeyong

    2011-02-01

    The process of controlling bacterial adhesion using an electric current deserves attention because of its ease of automation and environmentally friendly nature. This study investigated the role of electric currents (negative, positive, alternating) for preventing adhesion of Pseudomonas aeruginosa and achieving bacterial inactivation. Indium tin oxide (ITO) film was used as a working electrode to observe adhesion and inactivation under electric polarization. Electric current types were classified into negative, positive, and alternating current. The working electrode acted as a cathode or anode by applying a negative or positive current, and an alternating current indicates that the negative current was combined sequentially with the positive current. The numbers of adhered cells were compared under a flow condition, and the in situ behavior of the bacterial cells and the extent of their inactivation were also investigated using time-lapse recording and live/dead staining, respectively. The application of a negative current prevented bacterial adhesion significantly (∼81% at 15.0 μA cm(-2)). The positive current did not significantly inhibit adhesion (<20% at 15.0 μA cm(-2)), compared to the nonpolarized case. The alternating current had a similar effect as the negative current on preventing bacterial adhesion, but it also exhibited bactericidal effects, making it the most suitable method for bacterial adhesion control.

  14. Social evolution of toxic metal bioremediation in Pseudomonas aeruginosa

    PubMed Central

    O'Brien, Siobhán; Hodgson, David J.; Buckling, Angus

    2014-01-01

    Bacteria are often iron-limited, and hence produce extracellular iron-scavenging siderophores. A crucial feature of siderophore production is that it can be an altruistic behaviour (individually costly but benefitting neighbouring cells), thus siderophore producers can be invaded by non-producing social ‘cheats’. Recent studies have shown that siderophores can also bind other heavy metals (such as Cu and Zn), but in this case siderophore chelation actually reduces metal uptake by bacteria. These complexes reduce heavy metal toxicity, hence siderophore production may contribute to toxic metal bioremediation. Here, we show that siderophore production in the context of bioremediation is also an altruistic trait and can be exploited by cheating phenotypes in the opportunistic pathogen Pseudomonas aeruginosa. Specifically, we show that in toxic copper concentrations (i) siderophore non-producers evolve de novo and reach high frequencies, and (ii) producing strains are fitter than isogenic non-producing strains in monoculture, and vice versa in co-culture. Moreover, we show that the evolutionary effect copper has on reducing siderophore production is greater than the reduction observed under iron-limited conditions. We discuss the relevance of these results to the evolution of siderophore production in natural communities and heavy metal bioremediation. PMID:24898376

  15. Transcriptome Profiling of Antimicrobial Resistance in Pseudomonas aeruginosa.

    PubMed

    Khaledi, Ariane; Schniederjans, Monika; Pohl, Sarah; Rainer, Roman; Bodenhofer, Ulrich; Xia, Boyang; Klawonn, Frank; Bruchmann, Sebastian; Preusse, Matthias; Eckweiler, Denitsa; Dötsch, Andreas; Häussler, Susanne

    2016-08-01

    Emerging resistance to antimicrobials and the lack of new antibiotic drug candidates underscore the need for optimization of current diagnostics and therapies to diminish the evolution and spread of multidrug resistance. As the antibiotic resistance status of a bacterial pathogen is defined by its genome, resistance profiling by applying next-generation sequencing (NGS) technologies may in the future accomplish pathogen identification, prompt initiation of targeted individualized treatment, and the implementation of optimized infection control measures. In this study, qualitative RNA sequencing was used to identify key genetic determinants of antibiotic resistance in 135 clinical Pseudomonas aeruginosa isolates from diverse geographic and infection site origins. By applying transcriptome-wide association studies, adaptive variations associated with resistance to the antibiotic classes fluoroquinolones, aminoglycosides, and β-lactams were identified. Besides potential novel biomarkers with a direct correlation to resistance, global patterns of phenotype-associated gene expression and sequence variations were identified by predictive machine learning approaches. Our research serves to establish genotype-based molecular diagnostic tools for the identification of the current resistance profiles of bacterial pathogens and paves the way for faster diagnostics for more efficient, targeted treatment strategies to also mitigate the future potential for resistance evolution.

  16. Uranyl Precipitation by Pseudomonas aeruginosa via Controlled Polyphosphate Metabolism

    PubMed Central

    Renninger, Neil; Knopp, Roger; Nitsche, Heino; Clark, Douglas S.; Keasling, Jay D.

    2004-01-01

    The polyphosphate kinase gene from Pseudomonas aeruginosa was overexpressed in its native host, resulting in the accumulation of 100 times the polyphosphate seen with control strains. Degradation of this polyphosphate was induced by carbon starvation conditions, resulting in phosphate release into the medium. The mechanism of polyphosphate degradation is not clearly understood, but it appears to be associated with glycogen degradation. Upon suspension of the cells in 1 mM uranyl nitrate, nearly all polyphosphate that had accumulated was degraded within 48 h, resulting in the removal of nearly 80% of the uranyl ion and >95% of lesser-concentrated solutions. Electron microscopy, energy-dispersive X-ray spectroscopy, and time-resolved laser-induced fluorescence spectroscopy (TRLFS) suggest that this removal was due to the precipitation of uranyl phosphate at the cell membrane. TRLFS also indicated that uranyl was initially sorbed to the cell as uranyl hydroxide and was then precipitated as uranyl phosphate as phosphate was released from the cell. Lethal doses of radiation did not halt phosphate secretion from polyphosphate-filled cells under carbon starvation conditions. PMID:15574942

  17. Ginger Extract Inhibits Biofilm Formation by Pseudomonas aeruginosa PA14

    PubMed Central

    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

  18. Global transcriptional responses to triclosan exposure in Pseudomonas aeruginosa.

    PubMed

    Chuanchuen, Rungtip; Schweizer, Herbert P

    2012-08-01

    Global gene transcription was assessed by microarray experiments following treatment of a triclosan-susceptible Δ(mexAB-oprM) Pseudomonas aeruginosa strain with subinhibitory concentrations of triclosan. Expression patterns of selected genes were verified by quantitative real-time PCR analysis. The results showed that triclosan exposure had a profound effect on gene expression, affecting 44% of the genes present on the Affymetrix GeneChip(®), with 28% of genes being significantly upregulated and 16% being significantly downregulated in triclosan-treated cells. Genes encoding membrane proteins, transporters of small molecules, aspects of amino acid metabolism, and transcriptional regulators were significantly over-represented among the more strongly upregulated or downregulated genes in triclosan-treated cells. Quorum sensing-regulated genes were among the most strongly downregulated genes, presumably because of decreased acyl-acyl carrier protein pools and the resulting reduced acyl-homoserine lactone molecule synthesis. Surprisingly, iron homeostasis was completed perturbed in triclosan-exposed cells, with iron acquisition systems being strongly downregulated and iron storage systems significantly upregulated, thus mimicking conditions of excess iron. The profound perturbations of cellular metabolism via specific and global mechanisms may explain why triclosan is such a potent antimicrobial in susceptible bacteria.

  19. Heritability of Respiratory Infection with Pseudomonas aeruginosa in Cystic Fibrosis

    PubMed Central

    Green, Deanna M.; Collaco, J. Michael; McDougal, Kathryn E.; Naughton, Kathleen M.; Blackman, Scott M.; Cutting, Garry R.

    2013-01-01

    Objective To quantify the relative contribution of factors other than cystic fibrosis transmembrane conductance regulator genotype and environment on the acquisition of Pseudomonas aeruginosa (Pa) by patients with cystic fibrosis. Study design Lung infection with Pa and mucoid Pa was assessed using a co-twin study design of 44 monozygous (MZ) and 17 dizygous (DZ) twin pairs. Two definitions were used to establish infection: first positive culture and persistent positive culture. Genetic contribution to infection (ie, heritability) was estimated based on concordance analysis, logistic regression, and age at onset of infection through comparison of intraclass correlation coefficients. Results Concordance for persistent Pa infection was higher in MZ (0.83; 25 of 30 pairs) than DZ twins (0.45; 5 of 11 pairs), generating a heritability of 0.76. Logistic regression adjusted for age corroborated genetic control of persistent Pa infection. The correlation for age at persistent Pa infection was higher in MZ twins (0.589; 95% CI, 0.222-0.704) than in DZ twins (0.162; 95% CI, −0.352 to 0.607), generating a heritability of 0.85. Conclusion Genetic modifiers play a significant role in the establishment and timing of persistent Pa infection in individuals with cystic fibrosis. PMID:22364820

  20. Classification of Pseudomonas aeruginosa O antigens by immunoelectrophoresis.

    PubMed

    Lányi, B; Adám, M M; Szentmihályi, A

    1975-05-01

    Heated saline extracts of 89 strains, and (1) supernates of phenol-water extracts (L1 fractions), (2) purified lipopolysaccharide, (3) trichloracetic-acid (TCA) extracts, and (4) sodium-hydroxide extracts of 23 strains representing all Pseudomonas aeruginosa O antigens were subjected electrophoresis. Precipitation lines obtained with homologous and heterologous antisera were evaluated by electrodensitometric measurement. The characteristics of the immunoelectrophoretic groups established were as follows. Group I: two lines running at different rates towards the anode; three subgroups on the basis of the behaviour of alkali-treated antigens. Group II: triple line at the starting well, alkali sensitive. Group III: triple line at the starting well, alkali resistant; two subgroups according to reactivity or non-reactivity of L1 fractions. Group IV: triple line on the cathode side, alkali resistant, L1 fraction non-reactive. Group V: single line on the anode side, alkali sensitive, L1 fraction and TCA extract non-reactive. O antigens identified by agglutination corresponded closely with the immunoelectrophoretic pattern: strains with identical O antigens or sharing major somatic components fell, with one exception, into the same immunoelectrophoretic group. PMID:806687

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

    PubMed

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

    2009-09-01

    Mesotherapy is a treatment method devised for controlling several diseases by means of subcutaneous microinjections given at or around the affected areas at short time intervals. It is used to treat a variety of medical conditions, amongst which all orthopaedic diseases and rheumatic pain. Mesotherapy is especially indicated for neck pain. The mechanism of action is twofold: a pharmacological effect due to the drug administered, and a reflexogenic effect, the skin containing many nerve endings that are sensitive to the mechanical action of the needle. Although this therapy is safe, like any other medical intervention it cannot be considered free of complications that may occur, such as allergies, haematomas, bruising, wheals, granulomas and telangiectasias. Infective complications are also possible, due to pathogenic bacteria that are inoculated through contamination of products, of the materials used for the procedure or even from germs on the skin. We present the case of a patient who had cervical lymphadenopathy due to Pseudomonas aeruginosa after mesotherapy treatment for neck pain. PMID:19838089

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

    PubMed

    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.

  3. Characterization of adhesive exopolysaccharide (EPS) produced by Pseudomonas aeruginosa under starvation conditions.

    PubMed

    Myszka, Kamila; Czaczyk, Katarzyna

    2009-06-01

    Pseudomonas aeruginosa synthesizes large quantities of exopolysaccharide (EPS), making it an excellent model organism for the study of EPS-mediated adhesion. The purpose of this investigation was to evaluate the influence of limited nutrients availability in the culture medium on the composition of EPS produced by P. aeruginosa. The relationship between the EPS production and the adhesion process of the P. aeruginosa cells to stainless steel surface (type 316 L) under starvation conditions were also examined. In all experimental variants P. aeruginosa produced more EPS with an increase of incubation period upon starvation conditions. Under limited nutrients condition, glucose dominated in the EPS materials. After 6 days of the process, only glucosyl units were detected in the extracellular matrix produced by nutrient-deprived P. aeruginosa cells. These extracellular molecules promoted more advanced stages of P. aeruginosa biofilm formation on the surface of stainless steel.

  4. A risk assessment of Pseudomonas aeruginosa in swimming pools: a review.

    PubMed

    Rice, Scott A; van den Akker, Ben; Pomati, Francesco; Roser, David

    2012-06-01

    Despite routine monitoring and disinfection, treated swimming pools are frequently contaminated with the opportunistic pathogen Pseudomonas aeruginosa, which can represent a significant public health threat. This review was undertaken to identify the current understanding of risk factors associated with pool operation with respect to P. aeruginosa. The ecology and factors that promote growth of P. aeruginosa in the pool environment are complex and dynamic and so we applied a systematic risk assessment approach to integrate existing data, with the aim to improve pool management and safety. Sources of P. aeruginosa, types of infections, dose responses, routes of transmission, as well as the efficacy of current disinfectant treatments were reviewed. This review also highlights the critical knowledge gaps that are required for a more robust, quantitative risk assessment of P. aeruginosa. Quantitative risk management strategies have been successfully applied to drinking water systems and should similarly be amenable to developing a better understanding of the risk posed by P. aeruginosa in swimming pools.

  5. Nanoscale Adhesion Forces of Pseudomonas aeruginosa Type IV Pili

    PubMed Central

    2015-01-01

    A variety of bacterial pathogens use nanoscale protein fibers called type IV pili to mediate cell adhesion, a primary step leading to infection. Currently, how these nanofibers respond to mechanical stimuli and how this response is used to control adhesion is poorly understood. Here, we use atomic force microscopy techniques to quantify the forces guiding the adhesion of Pseudomonas aeruginosa type IV pili to surfaces. Using chemical force microscopy and single-cell force spectroscopy, we show that pili strongly bind to hydrophobic surfaces in a time-dependent manner, while they weakly bind to hydrophilic surfaces. Individual nanofibers are capable of withstanding forces up to 250 pN, thereby explaining how they can resist mechanical stress. Pulling on individual pili yields constant force plateaus, presumably reflecting conformational changes, as well as nanospring properties that may help bacteria to withstand physiological shear forces. Analysis of mutant strains demonstrates that these mechanical responses originate solely from type IV pili, while flagella and the cell surface localized and proposed pili-associated adhesin PilY1 play no direct role. We also demonstrate that bacterial–host interactions involve constant force plateaus, the extension of bacterial pili, and the formation of membrane tethers from host cells. We postulate that the unique mechanical responses of type IV pili unravelled here enable the bacteria to firmly attach to biotic and abiotic surfaces and thus maintain attachment when subjected to high shear forces under physiological conditions, helping to explain why pili play a critical role in colonization of the host. PMID:25286300

  6. Isolation and characterization of gallium resistant Pseudomonas aeruginosa mutants.

    PubMed

    García-Contreras, Rodolfo; Lira-Silva, Elizabeth; Jasso-Chávez, Ricardo; Hernández-González, Ismael L; Maeda, Toshinari; Hashimoto, Takahiro; Boogerd, Fred C; Sheng, Lili; Wood, Thomas K; Moreno-Sánchez, Rafael

    2013-12-01

    Pseudomonas aeruginosa PA14 cells resistant to the novel antimicrobial gallium nitrate (Ga) were developed using transposon mutagenesis and by selecting spontaneous mutants. The mutants showing the highest growth in the presence of Ga were selected for further characterization. These mutants showed 4- to 12-fold higher Ga minimal inhibitory growth concentrations and a greater than 8-fold increase in the minimum biofilm eliminating Ga concentration. Both types of mutants produced Ga resistant biofilms whereas the formation of wild-type biofilms was strongly inhibited by Ga. The gene interrupted in the transposon mutant was hitA, which encodes a periplasmic iron binding protein that delivers Fe³⁺ to the HitB iron permease; complementation of the mutant with the hitA gene restored the Ga sensitivity. This hitA mutant showed a 14-fold decrease in Ga internalization versus the wild-type strain, indicating that the HitAB system is also involved in the Ga uptake. Ga uptake in the spontaneous mutant was also lower, although no mutations were found in the hitAB genes. Instead, this mutant harbored 64 non-silent mutations in several genes including those of the phenazine pyocyanin biosynthesis. The spontaneous mutant produced 2-fold higher pyocyanin basal levels than the wild-type; the addition of this phenazine to wild-type cultures protected them from the Ga bacteriostatic effect. The present data indicate that mutations affecting Ga transport and probably pyocyanin biosynthesis enable cells to develop resistance to Ga.

  7. The Multiple Signaling Systems Regulating Virulence in Pseudomonas aeruginosa

    PubMed Central

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

    2012-01-01

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

  8. Electron tunneling in single crystals of Pseudomonas aeruginosa azurins.

    PubMed

    Crane, B R; Di Bilio, A J; Winkler, J R; Gray, H B

    2001-11-28

    Rates of reduction of Os(III), Ru(III), and Re(I) by Cu(I) in His83-modified Pseudomonas aeruginosa azurins (M-Cu distance approximately 17 A) have been measured in single crystals, where protein conformation and surface solvation are precisely defined by high-resolution X-ray structure determinations: 1.7(8) x 10(6) s(-1) (298 K), 1.8(8) x 10(6) s(-1) (140 K), [Ru(bpy)2(im)(3+)-]; 3.0(15) x 10(6) s(-1) (298 K), [Ru(tpy)(bpy)(3+)-]; 3.0(15) x 10(6) s(-1) (298 K), [Ru(tpy)(phen)(3+)-]; 9.0(50) x 10(2) s(-1) (298 K), [Os(bpy)2(im)(3+)-]; 4.4(20) x 10(6) s(-1) (298 K), [Re(CO)3(phen)(+)] (bpy = 2,2'-bipyridine; im = imidazole; tpy = 2,2':6',2' '-terpyridine; phen = 1,10-phenanthroline). The time constants for electron tunneling in crystals are roughly the same as those measured in solution, indicating very similar protein structures in the two states. High-resolution structures of the oxidized (1.5 A) and reduced (1.4 A) states of Ru(II)(tpy)(phen)(His83)Az establish that very small changes in copper coordination accompany reduction but reveal a shorter axial interaction between copper and the Gly45 peptide carbonyl oxygen [2.6 A for Cu(II)] than had been recognized previously. Although Ru(bpy)2(im)(His83)Az is less solvated in the crystal, the reorganization energy for Cu(I) --> Ru(III) electron transfer falls in the range (0.6-0.8 eV) determined experimentally for the reaction in solution. Our work suggests that outer-sphere protein reorganization is the dominant activation component required for electron tunneling.

  9. Structural and Functional Characterization of Pseudomonas aeruginosa AlgX

    PubMed Central

    Riley, Laura M.; Weadge, Joel T.; Baker, Perrin; Robinson, Howard; Codée, Jeroen D. C.; Tipton, Peter A.; Ohman, Dennis E.; Howell, P. Lynne

    2013-01-01

    The exopolysaccharide alginate, produced by mucoid Pseudomonas aeruginosa in the lungs of cystic fibrosis patients, undergoes two different chemical modifications as it is synthesized that alter the properties of the polymer and hence the biofilm. One modification, acetylation, causes the cells in the biofilm to adhere better to lung epithelium, form microcolonies, and resist the effects of the host immune system and/or antibiotics. Alginate biosynthesis requires 12 proteins encoded by the algD operon, including AlgX, and although this protein is essential for polymer production, its exact role is unknown. In this study, we present the X-ray crystal structure of AlgX at 2.15 Å resolution. The structure reveals that AlgX is a two-domain protein, with an N-terminal domain with structural homology to members of the SGNH hydrolase superfamily and a C-terminal carbohydrate-binding module. A number of residues in the carbohydrate-binding module form a substrate recognition “pinch point” that we propose aids in alginate binding and orientation. Although the topology of the N-terminal domain deviates from canonical SGNH hydrolases, the residues that constitute the Ser-His-Asp catalytic triad characteristic of this family are structurally conserved. In vivo studies reveal that site-specific mutation of these residues results in non-acetylated alginate. This catalytic triad is also required for acetylesterase activity in vitro. Our data suggest that not only does AlgX protect the polymer as it passages through the periplasm but that it also plays a role in alginate acetylation. Our results provide the first structural insight for a wide group of closely related bacterial polysaccharide acetyltransferases. PMID:23779107

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

    PubMed

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

    2014-01-01

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

  11. Precipitating Pseudomonas aeruginosa antibodies and antimicrobial therapy in cystic fibrosis patients.

    PubMed

    Trancassini, M; de Vito, D; Cimino, G; Antonelli, M; Quattrucci, S; Cipriani, P

    1996-04-01

    Forty patients with cystic fibrosis were studied bacteriologically and serologically. Precipitating Pseudomonas aeruginosa antibodies were monitored by crossed-immunoelectrophoresis (CIE) in order to evaluate the possibility of preventing chronic colonization by Pseudomonas aeruginosa by cycles of antimicrobial therapy. Sputum or pharyngeal aspirate and serum samples from all patients were analyzed by means of spread on selective media and CIE, respectively. Significant differences in the number of precipitins were obtained: noncolonized and intermittently colonized patients had no precipitins, whereas the number of precipitins in the chronically colonized patients varied from 11 to 44. An increase in the number of precipitins could be a good marker for initiation of therapy with antimicrobial agents that are either active against Pseudomonas aeruginosa or able to inhibit the release of virulence factors. PMID:8781882

  12. Determination of the O-serovars of Pseudomonas aeruginosa by slide coagglutination.

    PubMed

    Ansorg, R; Knoche, M

    1984-06-01

    Determination of the somatic (O-) antigens of Pseudomonas aeruginosa by conventional slide agglutination is frequently complicated by the barely discernible, slow reaction of native cells. For diagnostic purposes a more practical procedure, a coagglutination test, has been developed in which protein A bearing Staphylococcus aureus (ATCC 12598) cells are added to the agglutination process occurring between specific anti-O serum and native Pseudomonas aeruginosa. Compared to the conventional method, slide O-coagglutination yields larger agglutinates in a shorter mean reaction time, i.e. one minute vs four minutes. Moreover, strains not reacting in the O-agglutination method or reacting only with polyvalent anti-O serum can be grouped by O-coagglutination, and cross reactions between reference strains of different O-groups do not occur. This method facilitates O-grouping of Pseudomonas aeruginosa in epidemiological investigations. PMID:6205872

  13. Multidrug resistant Pseudomonas aeruginosa infection in children undergoing chemotherapy and hematopoietic stem cell transplantation.

    PubMed

    Caselli, Désirée; Cesaro, Simone; Ziino, Ottavio; Zanazzo, Giulio; Manicone, Rosaria; Livadiotti, Susanna; Cellini, Monica; Frenos, Stefano; Milano, Giuseppe M; Cappelli, Barbara; Licciardello, Maria; Beretta, Chiara; Aricò, Maurizio; Castagnola, Elio

    2010-09-01

    Pseudomonas aeruginosa is one leading gram-negative organism associated with nosocomial infections. Bacteremia is life-threatening in the immunocompromised host. Increasing frequency of multi-drug-resistant (MDRPA) strains is concerning. We started a retrospective survey in the pediatric hematology oncology Italian network. Between 2000 and 2008, 127 patients with Pseudomonas aeruginosa bacteremia were reported from 12 centers; 31.4% of isolates were MDRPA. Death within 30 days of a positive blood culture occurred in 19.6% (25/127) of total patients; in patients with MDRPA infection it occurred in 35.8% (14/39). In the multivariate analysis, only MDRPA had significant association with infection-related death. This is the largest series of Pseudomonas aeruginosa bacteremia cases from pediatric hematology oncology centers. Monitoring local bacterial isolates epidemiology is mandatory and will allow empiric antibiotic therapy to be tailored to reduce fatalities.

  14. Determination of genome size of Pseudomonas aeruginosa by PFGE: analysis of restriction fragments.

    PubMed Central

    Hector, J S; Johnson, A R

    1990-01-01

    Genomic DNA size was measured in three strains of Pseudomonas aeruginosa, ATCC 29260 (exotoxin A), ATCC 33467 (type I smooth) and ATCC 33468 (type 2 mucoid) by transverse alternating field electrophoresis of restriction fragments. Because of the high (67%) G + C content of Pseudomonas aeruginosa, restriction enzymes that recognize sequences with at least 4 AT base pairs were expected to be rare cutters. Eight enzymes produced fragments greater than 200 kb in size: Dral (TTT/AAA), Asnl (ATT/AAT), Hpal (GTT/AAC), AfIII (C/TTAAG), Xbal (T/CTAGA), Spel (A/CTAGT), Sspl (AAT/ATT) and Ndel (CA/TATG). All eight enzymes recognized one of three rare tetranucleotide sequences, TTAA, CTAG or ATAT. Pseudomonas aeruginosa strain 29260 has a genomic DNA size of 5573 kb. Strains 33467 and 33468 have identical restriction patterns and a possible deletion with a genomic size of 5407 kb. Images PMID:1972559

  15. VDUP1 exacerbates bacteremic shock in mice infected with Pseudomonas aeruginosa.

    PubMed

    Piao, Zheng-Hao; Kim, Mi Sun; Jeong, Mira; Yun, Sohyun; Lee, Suk Hyung; Sun, Hu-Nan; Song, Hae Young; Suh, Hyun-Woo; Jung, Haiyoung; Yoon, Suk Ran; Kim, Tae-Don; Lee, Young-Ho; Choi, Inpyo

    2012-11-01

    Vitamin-D3 upregulated protein-1 (VDUP1) is a stress response protein. Pseudomonas aeruginosa (P. aeruginosa) infection is a leading cause of death. Mice infected with live P. aeruginosa exhibit significantly decreased VDUP1 expression. However, the function of VDUP1 during P. aeruginosa-induced mouse bacteremic shock is unknown. To address the function of VDUP1 in P. aeruginosa-infected mice, we constructed a bacteremic shock model wherein both wild-type and VDUP1-deficient mice were infected intra-peritoneally with live P. aeruginosa. We found that VDUP1-deficient mice were more resistant to P. aeruginosa-induced bacteremic shock than wild-type mice, as shown by the increased survival, accelerated bacterial clearance and suppression of cytokine overproduction of the VDUP1-deficient mice. VDUP1 promoted the recruitment of neutrophils into the peritoneal cavities of infected mice. VDUP1 impeded the phagocytosis of non-opsonized P. aeruginosa via phosphatidylinositide 3-kinase (PI3K) pathway in macrophages. P. aeruginosa infection induced the generation of reactive oxygen species (ROS), and the increased production of ROS by the peritoneal cells of VDUP1-deficient mice was advantageous in clearing the bacteria. Overall, VDUP1 aggravates bacteremic shock; thus, VDUP1 can be considered a target molecule for the inhibition of P. aeruginosa-induced bacteremic shock.

  16. Metallo‐beta‐lactamases among imipenem‐resistant Pseudomonas aeruginosa in a brazilian university hospital

    PubMed Central

    Franco, Maria Renata Gomes; Caiaffa‐Filho, Hélio Hehl; Burattini, Marcelo Nascimento; Rossi, Flávia

    2010-01-01

    INTRODUCTION: Imipenem‐resistant Pseudomonas aeruginosa resulting from metallo‐β‐lactamases has been reported to be an important cause of nosocomial infection and is a critical therapeutic problem worldwide, especially in the case of bacteremia. OBJECTIVES: To determine the frequency of metallo‐β‐lactamases among imipenem‐resistant Pseudomonas aeruginosa isolates and to compare methods of phenotypic and molecular detection. METHODS: During 2006, 69 imipenem‐resistant Pseudomonas aeruginosa samples were isolated from blood and tested for metallo‐β‐lactamase production using phenotypic methods. Minimal Inhibitory Concentratrions (MIC) (µg/mL) was determined with commercial microdilution panels. Pulsed Field Gel Electrophoresis (PFGE) was performed among metallo‐β‐lactamase producers. RESULTS: Of all the blood isolates, 34.5% were found to be imipenem‐resistant Pseudomonas aeruginosa. Positive phenotypic tests for metallo‐β‐lactamases ranged from 28%‐77%, and Polymerase Chain Reaction (PCR) were positive in 30% (of note, 81% of those samples were blaSPM‐1 and 19% were blaVIM‐2). Ethylenediamine tetracetic acid (EDTA) combinations for the detected enzymes had low kappa values; thus, care should be taken when use it as a phenotypic indicator of MBL. Despite a very resistant antibiogram, four isolates demonstrated the worrisome finding of a colistin MIC in the resistant range. PFGE showed a clonal pattern. CONCLUSION: Metallo‐β‐lactamases among imipenem‐resistant Pseudomonas aeruginosa were detected in 30.4% of imipenem‐resistant Pseudomonas aeruginosa isolates. This number might have been higher if other genes were included. SPM‐1 was the predominant enzyme found. Phenotypic tests with low kappa values could be misleading when testing for metallo‐β‐lactamases. Polymerase Chain Reaction detection remains the gold standard. PMID:21049207

  17. Pseudomonas aeruginosa outbreak in a neonatal intensive care unit: a possible link to contaminated hand lotion.

    PubMed

    Becks, V E; Lorenzoni, N M

    1995-12-01

    This article describes a prolonged outbreak of Pseudomonas aeruginosa. The attack rate of this outbreak was 8.5%, with no associated mortality. Hand lotion contaminated with P. aeruginosa was implicated in the transmission of organisms; removal of this hand lotion ended the outbreak. Contaminated hand lotion applied to clean hands of health care workers may have led to direct inoculation of infants at high risk for infection.

  18. Incorporation of isotope from specifically labeled glucose into alginates of Pseudomonas aeruginosa and Azotobacter vinelandii.

    PubMed Central

    Lynn, A R; Sokatch, J R

    1984-01-01

    The incorporation of isotope from [6-14C]glucose into alginate by both Pseudomonas aeruginosa and Azotobacter vinelandii was 10-fold greater than that from either [1-14C]- or [2-14C]glucose, indicating preferential utilization of the bottom half of the glucose molecule for alginate synthesis. These data strongly suggest that the Entner - Doudoroff pathway plays a major role in alginate synthesis in both P. aeruginosa and A. vinelandii. PMID:6427189

  19. The role of quorum sensing in the in vivo virulence of Pseudomonas aeruginosa.

    PubMed

    Rumbaugh, K P; Griswold, J A; Hamood, A N

    2000-11-01

    Pseudomonas aeruginosa is an opportunistic pathogen that causes a wide variety of infections. The cell-density-dependent signaling mechanisms known as quorum sensing play a role in several of these infections including corneal, lung and burn wound infections. In addition, the quorum-sensing systems contribute to the ability of P. aeruginosa to form biofilms on medically important devices. The quorum-sensing systems accomplish their effect by controlling the production of different virulence factors and by manipulating the host immune response.

  20. Antibiotic Tolerance Induced by Lactoferrin in Clinical Pseudomonas aeruginosa Isolates from Cystic Fibrosis Patients

    PubMed Central

    Andrés, María T.; Viejo-Diaz, Mónica; Pérez, Francisco; Fierro, José F.

    2005-01-01

    Lactoferrin-induced cell depolarization and a delayed tobramycin-killing effect on Pseudomonas aeruginosa cells were correlated. This antibiotic tolerance effect (ATE) reflects the ability of a defense protein to modify the activity of an antibiotic as a result of its modulatory effect on bacterial physiology. P. aeruginosa isolates from cystic fibrosis patients showed higher ATE values (≤6-fold) than other clinical strains. PMID:15793153

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

    PubMed

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

    2011-02-01

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

  2. Growth and survival of Pseudomonas aeruginosa in some aromatic waters.

    PubMed

    Ibrahim, Y K; Ogunmodede, M S

    1991-01-01

    The ability of some aromatic waters at the in-use concentrations to enhance or inhibit the growth of microorganisms was determined by the antimicrobial preservative challenge method. Anise, chloroform, cinnamon, clove, dill, lemon, peppermint and rose waters were challenged with Ps. aeruginosa. Levels of the surviving cells at different times were determined by the pour plate method. The antimicrobial effect of the corresponding undiluted aromatic oils against Ps. aeruginosa was determined by the cup-plate method. Results showed that cinnamon water possesses profound and useful preservative activity against Ps. aeruginosa. The inhibitory effect of anise, chloroform and rose waters on Ps. aeruginosa is not much pronounced. Similarly, clove, dill and peppermint waters exhibited no significant preservative actions. Lemon water was found to enhance the growth of Ps. aeruginosa. The survival pattern of Ps. aeruginosa in the majority of the aromatic waters conforms with the antimicrobial actions of their undiluted oils.

  3. Irgasan-induced pigmentation in Serratia marcescens and Pseudomonas aeruginosa.

    PubMed

    Kranz, R G; Lynch, D L

    1979-01-01

    Two irgasan-resistant micro-organisms (P. aeruginosa and S. marcescens) were used to study the effects of various antibiotic and chemotherapeutic agents on pigment production. These agents included streptomycin, thallium acetate, polymyxin B, hexachlorophene, irgasan, prodigiosin and DMSO (dimethyl sulphoxide). Only irgasan, compared to other drugs and membrane-active agents showed the unique property of inducing pigmentation in both P. aeruginosa and S. marcescens, i.e. prodigiosin in S. marcescens and pyocyanin in P. aeruginosa.

  4. Expeditive synthesis of trithiotriazine-cored glycoclusters and inhibition of Pseudomonas aeruginosa biofilm formation

    PubMed Central

    Smadhi, Meriem; Gingras, Marc; Abderrahim, Raoudha

    2014-01-01

    Summary Readily accessible, low-valency glycoclusters based on a triazine core bearing D-galactose and L-fucose epitopes are able to inhibit biofilm formation by Pseudomonas aeruginosa. These multivalent ligands are simple to synthesize, are highly soluble, and can be either homofunctional or heterofunctional. The galactose-decorated cluster shows good affinity for Pseudomonas aeruginosa lectin lecA. They are convenient biological probes for investigating the roles of lecA and lecB in biofilm formation. PMID:25246957

  5. Antimicrobial resistance and molecular typing of pseudomonas aeruginosa isolated from surgical wounds in Lagos, Nigeria.

    PubMed

    Smith, Stella; Ganiyu, Olaniyi; John, Rachael; Fowora, Muinah; Akinsinde, Kehinde; Odeigah, Peter

    2012-01-01

    The aim of the study was to determine the resistance patterns of Pseudomonas aeruginosa isolates recovered from patients with surgical wounds in hospitals and also to investigate their epidemiological relatedness using molecular typing techniques. Twenty Pseudomonas sp. isolated from surgical wounds were subjected to antibiotic susceptibility testing by disk diffusion, plasmid profile, SDS-PAGE and PCR using the parC, gyr A gene and RAPD using the 1254 primer. The isolates showed resistance to 12 different antibiotics with six being 100% resistant. Plasmids were detected in 16 (80%) of the isolates. The RAPD-PCR using the primer 1254, SDS-PAGE classified the 20 Pseudomonas spp. into 5 and 6 types respectively. Pseudomona aeruginosa strains isolated from surgical wounds were generally resistant to a broad range of antibiotics and this is rather worrisome. The typing techniques classified the 20 isolates into 5 and 6 groups. PMID:22837123

  6. Phenazine production enhances extracellular DNA release via hydrogen peroxide generation in Pseudomonas aeruginosa

    PubMed Central

    Das, Theerthankar; Manefield, Mike

    2013-01-01

    In Pseudomonas aeruginosa eDNA is a crucial component essential for biofilm formation and stability. In this study we report that release of eDNA is influenced by the production of phenazine in P. aeruginosa. A ∆phzA-G mutant of P. aeruginosa PA14 deficient in phenazine production generated significantly less eDNA in comparison with the phenazine producing strains. The relationship between eDNA release and phenazine production is bridged via hydrogen peroxide (H2O2) generation and subsequent H2O2 mediated cell lysis and ultimately release of chromosomal DNA into the extracellular environment as eDNA. PMID:23710274

  7. Synthesis and biological properties of thiazole-analogues of pyochelin, a siderophore of Pseudomonas aeruginosa.

    PubMed

    Noël, Sabrina; Hoegy, Françoise; Rivault, Freddy; Rognan, Didier; Schalk, Isabelle J; Mislin, Gaëtan L A

    2014-01-01

    Pyochelin is a siderophore common to all strains of Pseudomonas aeruginosa utilized by this Gram-negative bacterium to acquire iron(III). FptA is the outer membrane transporter responsible of ferric-pyochelin uptake in P. aeruginosa. We describe in this Letter the synthesis and the biological properties ((55)Fe uptake, binding to FptA) of several thiazole analogues of pyochelin. Among them we report in this Letter the two first pyochelin analogues able to bind FptA without promoting any iron uptake in P. aeruginosa. PMID:24332092

  8. Isolation of a mucoid alginate-producing Pseudomonas aeruginosa strain from the equine guttural pouch.

    PubMed Central

    Govan, J R; Sarasola, P; Taylor, D J; Tatnell, P J; Russell, N J; Gacesa, P

    1992-01-01

    The isolation and characterization of a mucoid, alginate-producing strain of Pseudomonas aeruginosa from a nonhuman host, namely, in chondroids from an equine guttural pouch, is reported for the first time. Pure cultures of P. aeruginosa 12534 were isolated from a 17-month-old pony mare with a history of chronic bilateral mucopurulent nasal discharge from the right guttural pouch. Transmission electron microscopy of chondroids showed mucoid P. aeruginosa growing as microcolonies within a matrix of extracellular material. On the basis of expression of the mucoid phenotype under different growth conditions, P. aeruginosa 12534 belongs to group 1 and resembles other isolates carrying the muc-23 mutation. The bulk of the extracellular material was characterized as being alginate by chemical and 1H nuclear magnetic resonance analyses, which showed that it had a composition similar to that produced by isolates of P. aeruginosa from human patients with cystic fibrosis. Images PMID:1551975

  9. Insights into the respiratory tract microbiota of patients with cystic fibrosis during early Pseudomonas aeruginosa colonization

    SciTech Connect

    Keravec, Marlene; Mounier, Jerome; Prestat , Emmanuel; Vallet, Sophie; Jansson, Janet K.; Bergaud , Gaetaqn; Rosec, Silvain; Gourious, Stephanie; Rault, Gilles; Coton, Emmanuel; Barbier, George; Hery-Arnaud, Geneveieve

    2015-08-09

    Abstract Pseudomonas aeruginosa plays a major role in cystic fibrosis (CF) progression. Therefore, it is important to understand the initial steps of P. aeruginosa infection. The structure and dynamics of CF respiratory tract microbial communities during the early stages of P. aeruginosa colonization were characterized by pyrosequencing and cloning-sequencing. The respiratory microbiota showed high diversity, related to the young age of the CF cohort (mean age 10 years). Wide inter- and intra-individual variations were revealed. A common core microbiota of 5 phyla and 13 predominant genera was found, the majority of which were obligate anaerobes. A few genera were significantly more prevalent in patients never infected by P. aeruginosa. Persistence of an anaerobic core microbiota regardless of P. aeruginosa status suggests a major role of certain anaerobes in the pathophysiology of lung infections in CF. Some genera may be potential biomarkers of pulmonary infection state.

  10. The Pseudomonas aeruginosa Transcriptional Landscape Is Shaped by Environmental Heterogeneity and Genetic Variation

    PubMed Central

    Schniederjans, Monika; Khaledi, Ariane; Hornischer, Klaus; Schulz, Sebastian; Bielecka, Agata; Eckweiler, Denitsa; Pohl, Sarah; Häussler, Susanne

    2015-01-01

    ABSTRACT Phenotypic variability among bacteria depends on gene expression in response to different environments, and it also reflects differences in genomic structure. In this study, we analyzed transcriptome sequencing (RNA-seq) profiles of 151 Pseudomonas aeruginosa clinical isolates under standard laboratory conditions and of one P. aeruginosa type strain under 14 different environmental conditions. Our approach allowed dissection of the impact of the genetic background versus environmental cues on P. aeruginosa gene expression profiles and revealed that phenotypic variation was larger in response to changing environments than between genomically different isolates. We demonstrate that mutations within the global regulator LasR affect more than one trait (pleiotropy) and that the interaction between mutations (epistasis) shapes the P. aeruginosa phenotypic plasticity landscape. Because of pleiotropic and epistatic effects, average genotype and phenotype measures appeared to be uncorrelated in P. aeruginosa. PMID:26126853

  11. Insights into the respiratory tract microbiota of patients with cystic fibrosis during early Pseudomonas aeruginosa colonization

    DOE PAGES

    Keravec, Marlène; Mounier, Jérôme; Prestat, Emmanuel; Vallet, Sophie; Jansson, Janet K.; Burgaud, Gaëtan; Rosec, Sylvain; Gouriou, Stéphanie; Rault, Gilles; Coton, Emmanuel; et al

    2015-08-09

    Pseudomonas aeruginosa plays a major role in cystic fibrosis (CF) progression. Therefore, it is important to understand the initial steps of P. aeruginosa infection. The structure and dynamics of CF respiratory tract microbial communities during the early stages of P. aeruginosa colonization were characterized by pyrosequencing and cloning-sequencing. The respiratory microbiota showed high diversity, related to the young age of the CF cohort (mean age 10 years). Wide inter- and intra-individual variations were revealed. A common core microbiota of 5 phyla and 13 predominant genera was found, the majority of which were obligate anaerobes. A few genera were significantly moremore » prevalent in patients never infected by P. aeruginosa. Persistence of an anaerobic core microbiota regardless of P. aeruginosa status suggests a major role of certain anaerobes in the pathophysiology of lung infections in CF. Some genera may be potential biomarkers of pulmonary infection state.« less

  12. Genetic characterization of Pseudomonas aeruginosa-resistant isolates at the university teaching hospital in Iran

    PubMed Central

    Fazeli, Hossein; Sadighian, Hooman; Esfahani, Bahram Nasr; Pourmand, Mohammad Reza

    2015-01-01

    Background: Pseudomonas aeruginosa is an opportunistic pathogen that is commonly responsible for nosocomial infections. The aim of this study was to perform a genotyping analysis of the Pseudomonas aeruginosa-resistant isolates by the multilocus sequence typing (MLST) method at the university teaching hospital in Iran. Materials and Methods: Antimicrobial susceptibility was analyzed for P. aeruginosa isolates. Ceftazidime-resistant (CAZres) isolates with a positive double-disc synergy test were screened for the presence of extended-spectrum β-lactamase-encoding genes. Phenotypic tests to detect the metallo-β-lactamase strains of P. aeruginosa were performed on imipenem-resistant (IMPres) isolates. Selected strains were characterized by MLST. Results: Of 35 P. aeruginosa isolates, 71%, 45% and 45% of isolates were CAZres, IMPres and multidrug resistant (MDR), respectively. Fifty-seven percent of the isolates carried the blaOXAgroup-1. All the five typed isolates were ST235. Isolates of ST235 that were MDR showed a unique resistance pattern. Conclusion: This study shows a high rate of MDR P. aeruginosa isolates at the university teaching hospital in Iran. It seems MDR isolates of P. aeruginosa ST235 with unique resistance pattern disseminated in this hospital. PMID:26380241

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

    PubMed Central

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

    2010-01-01

    Maggot debridement therapy (MDT) is widely used for debridement of chronic infected wounds; however, for wounds harbouring specific bacteria limited effect or failure of the treatment has been described. Here we studied the survival of Lucilia sericata maggots encountering Pseudomonas aeruginosa PAO1 in a simple assay with emphasis on the quorum-sensing (QS)-regulated virulence. The maggots were challenged with GFP-tagged P. aeruginosa wild-type (WT) PAO1 and a GFP-tagged P. aeruginosa ΔlasR rhlR (ΔRR) QS-deficient mutant in different concentrations. Maggots were killed in the presence of WT PAO1 whereas the challenge with the QS mutant showed a survival reduction of ∼25 % compared to negative controls. Furthermore, bacterial intake by the maggots was lower in the presence of WT PAO1 compared to the PAO1 ΔRR mutant. Maggot excretions/secretions (ES) were assayed for the presence of QS inhibitors; only high doses of ES showed inhibition of QS in P. aeruginosa. Thus P. aeruginosa was shown to be toxic to L. sericata maggots. This, coupled to the preferential feeding by the maggots and reduced ingestion of P. aeruginosa, could explain MDT failure in wounds colonized by P. aeruginosa. Wounds heavily colonized with P. aeruginosa should be a counterindication for MDT unless used in combination with a pre-treatment with other topical therapeutics targeting P. aeruginosa. PMID:19892758

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

    PubMed

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

    2010-02-01

    Maggot debridement therapy (MDT) is widely used for debridement of chronic infected wounds; however, for wounds harbouring specific bacteria limited effect or failure of the treatment has been described. Here we studied the survival of Lucilia sericata maggots encountering Pseudomonas aeruginosa PAO1 in a simple assay with emphasis on the quorum-sensing (QS)-regulated virulence. The maggots were challenged with GFP-tagged P. aeruginosa wild-type (WT) PAO1 and a GFP-tagged P. aeruginosa DeltalasR rhlR (DeltaRR) QS-deficient mutant in different concentrations. Maggots were killed in the presence of WT PAO1 whereas the challenge with the QS mutant showed a survival reduction of approximately 25 % compared to negative controls. Furthermore, bacterial intake by the maggots was lower in the presence of WT PAO1 compared to the PAO1 DeltaRR mutant. Maggot excretions/secretions (ES) were assayed for the presence of QS inhibitors; only high doses of ES showed inhibition of QS in P. aeruginosa. Thus P. aeruginosa was shown to be toxic to L. sericata maggots. This, coupled to the preferential feeding by the maggots and reduced ingestion of P. aeruginosa, could explain MDT failure in wounds colonized by P. aeruginosa. Wounds heavily colonized with P. aeruginosa should be a counterindication for MDT unless used in combination with a pre-treatment with other topical therapeutics targeting P. aeruginosa.

  15. Antibiofilm activity of Streptomyces sp. BFI 230 and Kribbella sp. BFI 1562 against Pseudomonas aeruginosa.

    PubMed

    Kim, Yong-Guy; Lee, Jin-Hyung; Kim, Chang-Jin; Lee, Jae-Chan; Ju, Yoon Jung; Cho, Moo Hwan; Lee, Jintae

    2012-12-01

    Members of the actinomycetes family are a rich source of bioactive compounds including diverse antibiotics. This study sought to identify novel and non-toxic biofilm inhibitors from the actinomycetes library for reducing the biofilm formation of Pseudomonas aeruginosa PAO1. After the screening of 4104 actinomycetes strains, we found that the culture spent medium (1 %, v/v) of Streptomyces sp. BFI 230 and Kribbella sp. BFI 1562 inhibited P. aeruginosa biofilm formation by 90 % without affecting the growth of planktonic P. aeruginosa cells, while the spent media enhanced the swarming motility of P. aeruginosa. Global transcriptome analyses revealed that the spent medium of Streptomyces sp. BFI 230 induced expression of phenazine, pyoverdine, pyochelin synthesis genes, and iron uptake genes in P. aeruginosa. The addition of exogenous iron restored the biofilm formation and swarming motility of P. aeruginosa in the presence of the spent medium of Streptomyces sp. BFI 230, which suggests that the Streptomyces sp. BFI 230 strain interfered iron acquisition in P. aeruginosa. Experiments on solvent extraction, heat treatment, and proteinase K treatment suggested that hydrophilic compound(s), possibly extracellular peptides or proteins from Streptomyces sp. BFI 230 cause the biofilm reduction of P. aeruginosa. Together, this study indicates that actinomycetes strains have an ability to control the biofilm of P. aeruginosa. PMID:22722911

  16. Cystic fibrosis transmembrane conductance regulator and caveolin-1 regulate epithelial cell internalization of Pseudomonas aeruginosa

    PubMed Central

    Bajmoczi, Milan; Gadjeva, Mihaela; Alper, Seth L.; Pier, Gerald B.; Golan, David E.

    2009-01-01

    Patients with cystic fibrosis (CF) exhibit defective innate immunity and are susceptible to chronic lung infection with Pseudomonas aeruginosa. To investigate the molecular bases for the hypersusceptibility of CF patients to P. aeruginosa, we used the IB3-1 cell line with two defective CF transmembrane conductance regulator (CFTR) genes (ΔF508/W1282X) to generate isogenic stable, clonal lung epithelial cells expressing wild-type (WT)-CFTR with an NH2-terminal green fluorescent protein (GFP) tag. GFP-CFTR exhibited posttranslational modification, subcellular localization, and anion transport function typical of WT-CFTR. P. aeruginosa internalization, a component of effective innate immunity, required functional CFTR and caveolin-1, as shown by: 1) direct correlation between GFP-CFTR expression levels and P. aeruginosa internalization; 2) enhanced P. aeruginosa internalization by aminoglycoside-induced read through of the CFTR W1282X allele in IB3-1 cells; 3) decreased P. aeruginosa internalization following siRNA knockdown of GFP-CFTR or caveolin-1; and 4) spatial association of P. aeruginosa with GFP-CFTR and caveolin-1 at the cell surface. P. aeruginosa internalization also required free lateral diffusion of GFP-CFTR, allowing for bacterial coclustering with GFP-CFTR and caveolin-1 at the plasma membrane. Thus efficient initiation of innate immunity to P. aeruginosa requires formation of an epithelial “internalization platform” involving both caveolin-1 and functional, laterally mobile CFTR. PMID:19386787

  17. Pseudomonas aeruginosa PAO1 exopolysaccharides are important for mixed species biofilm community development and stress tolerance

    PubMed Central

    Periasamy, Saravanan; Nair, Harikrishnan A. S.; Lee, Kai W. K.; Ong, Jolene; Goh, Jie Q. J.; Kjelleberg, Staffan; Rice, Scott A.

    2015-01-01

    Pseudomonas aeruginosa PAO1 produces three polysaccharides, alginate, Psl, and Pel that play distinct roles in attachment and biofilm formation for monospecies biofilms. Considerably less is known about their role in the development of mixed species biofilm communities. This study has investigated the roles of alginate, Psl, and Pel during biofilm formation of P. aeruginosa in a defined and experimentally informative mixed species biofilm community, consisting of P. aeruginosa, Pseudomonas protegens, and Klebsiella pneumoniae. Loss of the Psl polysaccharide had the biggest impact on the integration of P. aeruginosa in the mixed species biofilms, where the percent composition of the psl mutant was significantly lower (0.06%) than its wild-type (WT) parent (2.44%). In contrast, loss of the Pel polysaccharide had no impact on mixed species biofilm development. Loss of alginate or its overproduction resulted in P. aeruginosa representing 8.4 and 18.11%, respectively, of the mixed species biofilm. Dual species biofilms of P. aeruginosa and K. pneumoniae were not affected by loss of alginate, Pel, or Psl, while the mucoid P. aeruginosa strain achieved a greater biomass than its parent strain. When P. aeruginosa was grown with P. protegens, loss of the Pel or alginate polysaccharides resulted in biofilms that were not significantly different from biofilms formed by the WT PAO1. In contrast, overproduction of alginate resulted in biofilms that were comprised of 35–40% of P. aeruginosa, which was significantly higher than the WT (5–20%). Loss of the Psl polysaccharide significantly reduced the percentage composition of P. aeruginosa in dual species biofilms with P. protegens (<1%). Loss of the Psl polysaccharide significantly disrupted the communal stress resistance of the three species biofilms. Thus, the polysaccharide composition of an individual species significantly impacts mixed species biofilm development and the emergent properties of such communities. PMID

  18. Purification and antibiofilm activity of AHL-lactonase from endophytic Enterobacter aerogenes VT66.

    PubMed

    Rajesh, P S; Rai, V Ravishankar

    2015-11-01

    The opportunistic pathogen Pseudomonas aeruginosa uses biofilm lifestyle to resist antibiotic treatment. In our study, endophytic bacterium Enterobacter aerogenes VT66 quenched the N-acyl homoserine lactone (AHL) molecules produced by P. aeruginosa PAO1. The quorum quenching activity was attributed to the presence of AHL-lactonase. The AHL-lactonase was purified using column chromatography and purified AHL-lactonase was applied for the control of biofilm formation in P. aeruginosa PAO1. The results showed that purified AHL-lactonase obtained with a molecular weight about 30kDa was able to inhibit more than 70% of biofilm in P. aeruginosa PAO1 (P<0.001). Antibiofilm activity of AHL-lactonase was correlated well with results from staining technique used to determine inhibition of biomass and viable cell activity. Therefore, results unambiguously confirm that the AHL-lactonase from E. aerogenes VT66 could be used as antibiofilm therapeutics in P. aeruginosa associated biomedical applications. PMID:26432367

  19. Antimicrobial effects of Pseudomonas aeruginosa on survivability and recovery of Campylobacter jejuni on poultry products.

    PubMed

    Davis, M A; Conner, D E

    2007-04-01

    Three types of poultry products representing differences in skin coverage were tested to determine the ability of Pseudomonas aeruginosa to inhibit growth of Campylobacter jejuni. Processed ready-to-cook poultry carcasses were obtained from the Poultry Research Unit at Auburn University and were not subjected to any treatment to reduce or eliminate the native microflora on the carcasses. Carcasses were cut into wing sections (drumette, flat, tip), split breast pieces (with and without bone), and boneless, skinless breast pieces. Equal numbers of the 3 product types were subjected to 1 of 6 treatments: 1) uninoculated, 2) C. jejuni only, 3) P. aeruginosa type 1 only, 4) P. aeruginosa type 2 only, 5) C. jejuni + P. aeruginosa type 1, or 6) C. jejuni + P. aeruginosa type 2. Products were inoculated at 10(4) to 10(5) cfu. Postinoculation, equal numbers of product type were also subjected to the following: 1) aerobic or vacuum packaging, 2) storage temperature of 4 or 10 degrees C, and 3) storage of 0, 1, 2, 3, or 4 d. Products were sampled after storage duration to determine the population of C. jejuni and P. aeruginosa. Individual pieces were rinsed with 50 mL of buffered peptone water. The recovered rinse was used to make appropriate dilutions and spiral plated onto Campy-Cefex and Pseudomonas P agars. Campy-Cefex plates were incubated microaerophilically at 42 degrees C for 48 h, whereas Pseudomonas P plates were incubated aerobically at 37 degrees C for 24 to 48 h. Random suspect colonies on Campy-Cefex plates were confirmed by cell morphology when viewed under microscopic examination. Suspect colonies on Pseudomonas P plates produced a blue color in the medium indicative of glycerol reduction. At both 4 and 10 degrees C, neither type of P. aeruginosa inhibited the growth or survival of C. jejuni compared to plates that were inoculated with C. jejuni only. PMID:17369550

  20. Molecular analysis of the Pseudomonas aeruginosa regulatory genes ptxR and ptxS.

    PubMed

    Colmer, J A; Hamood, A N

    2001-09-01

    We have previously described two Pseudomonas aeruginosa genes, ptxR, which enhances toxA and pvc (the pyoverdine chromophore operon) expression, and ptxS, the first gene of the kgu operon for the utilization of 2-ketogluconate by P. aeruginosa. ptxS interferes with the effect of ptxR on toxA expression. In this study, we have utilized DNA hybridization experiments to determine the presence of ptxR and ptxS homologous sequences in several gram-negative bacteria. ptxR homologous sequences were detected in P. aeruginosa strains only, while ptxS homologous sequences were detected in P. aeruginosa, Pseudomonas putida, and Pseudomonas fluorescens. Using Northern blot hybridization experiments and a ptxS-lacZ fusion plasmid, we have shown that P. aeruginosa ptxR and ptxS are expressed in P. putida and P. fluorescens. Additional Northern blot hybridization experiments confirmed that ptxS is transcribed in P. putida and P. fluorescens strains that carried no plasmid. The presence of a PtxS homologue in these strains was examined by DNA-gel shift experiments. Specific gel shift bands were detected when the lysates of P. aeruginosa, P. putida, and P. fluorescens were incubated with the ptxS operator site as probe. kgu-hybridizing sequences were detected in P. putida and P. fluorescens. These results suggest that (i) ptxR is present in P. aeruginosa, while ptxS is present in P. aeruginosa, P. putida, and P. fluorescens; (ii) both ptxR and ptxS are expressed in P. putida and P fluorescens; and (iii) a PtxS homologue may exist in P. putida and P. fluorescens. PMID:11683464

  1. Pseudomonas aeruginosa Phenotypes Associated With Eradication Failure in Children With Cystic Fibrosis

    PubMed Central

    Mayer-Hamblett, Nicole; Ramsey, Bonnie W.; Kulasekara, Hemantha D.; Wolter, Daniel J.; Houston, Laura S.; Pope, Christopher E.; Kulasekara, Bridget R.; Armbruster, Catherine R.; Burns, Jane L.; Retsch-Bogart, George; Rosenfeld, Margaret; Gibson, Ronald L.; Miller, Samuel I.; Khan, Umer; Hoffman, Lucas R.

    2014-01-01

    Background. Pseudomonas aeruginosa is a key respiratory pathogen in people with cystic fibrosis (CF). Due to its association with lung disease progression, initial detection of P. aeruginosa in CF respiratory cultures usually results in antibiotic treatment with the goal of eradication. Pseudomonas aeruginosa exhibits many different phenotypes in vitro that could serve as useful prognostic markers, but the relative relationships between these phenotypes and failure to eradicate P. aeruginosa have not been well characterized. Methods. We measured 22 easily assayed in vitro phenotypes among the baseline P. aeruginosa isolates collected from 194 participants in the 18-month EPIC clinical trial, which assessed outcomes after antibiotic eradication therapy for newly identified P. aeruginosa. We then evaluated the associations between these baseline isolate phenotypes and subsequent outcomes during the trial, including failure to eradicate after antipseudomonal therapy, emergence of mucoidy, and occurrence of an exacerbation. Results. Baseline P. aeruginosa isolates frequently exhibited phenotypes thought to represent chronic adaptation, including mucoidy. Wrinkly colony surface and irregular colony edges were both associated with increased risk of eradication failure (hazard ratios [95% confidence intervals], 1.99 [1.03–3.83] and 2.14 [1.32–3.47], respectively). Phenotypes reflecting defective quorum sensing were significantly associated with subsequent mucoidy, but no phenotype was significantly associated with subsequent exacerbations during the trial. Conclusions. Pseudomonas aeruginosa phenotypes commonly considered to reflect chronic adaptation were observed frequently among isolates at early detection. We found that 2 easily assayed colony phenotypes were associated with failure to eradicate after antipseudomonal therapy, both of which have been previously associated with altered biofilm formation and defective quorum sensing. PMID:24863401

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

    PubMed

    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.

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

    PubMed

    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

  4. Quinolone signaling in the cell-to-cell communication system of Pseudomonas aeruginosa.

    PubMed

    Pesci, E C; Milbank, J B; Pearson, J P; McKnight, S; Kende, A S; Greenberg, E P; Iglewski, B H

    1999-09-28

    Numerous species of bacteria use an elegant regulatory mechanism known as quorum sensing to control the expression of specific genes in a cell-density dependent manner. In Gram-negative bacteria, quorum sensing systems function through a cell-to-cell signal molecule (autoinducer) that consists of a homoserine lactone with a fatty acid side chain. Such is the case in the opportunistic human pathogen Pseudomonas aeruginosa, which contains two quorum sensing systems (las and rhl) that operate via the autoinducers, N-(3-oxododecanoyl)-L-homoserine lactone and N-butyryl-L-homoserine lactone. The study of these signal molecules has shown that they bind to and activate transcriptional activator proteins that specifically induce numerous P. aeruginosa virulence genes. We report here that P. aeruginosa produces another signal molecule, 2-heptyl-3-hydroxy-4-quinolone, which has been designated as the Pseudomonas quinolone signal. It was found that this unique cell-to-cell signal controlled the expression of lasB, which encodes for the major virulence factor, LasB elastase. We also show that the synthesis and bioactivity of Pseudomonas quinolone signal were mediated by the P. aeruginosa las and rhl quorum sensing systems, respectively. The demonstration that 2-heptyl-3-hydroxy-4-quinolone can function as an intercellular signal sheds light on the role of secondary metabolites and shows that P. aeruginosa cell-to-cell signaling is not restricted to acyl-homoserine lactones.

  5. VEB-1-like extended-spectrum beta-lactamases in Pseudomonas aeruginosa, Kuwait.

    PubMed

    Poirel, L; Rotimi, V O; Mokaddas, E M; Karim, A; Nordmann, P

    2001-01-01

    Two clinical Pseudomonas aeruginosa isolates from patients in intensive care units in Kuwait were resistant to expanded-spectrum cephalosporins and showed a synergistic effect between ceftazidime and clavulanic acid. This is the first report of extended-spectrum enzymes from nosocomial isolates from the Middle East.

  6. Multidrug-Resistant Pseudomonas aeruginosa Infection in a Child with Cystic Fibrosis.

    PubMed

    Ang, Jocelyn Y; Abdel-Haq, Nahed; Zhu, Frank; Thabit, Abrar K; Nicolau, David P; Satlin, Michael J; van Duin, David

    2016-10-01

    We describe a pediatric cystic fibrosis patient who developed a pulmonary exacerbation due to two multidrug-resistant (MDR) Pseudomonas aeruginosa isolates. In addition to these MDR organisms, the case was further complicated by β-lactam allergy. Despite the MDR phenotype, both isolates were susceptible to an antimicrobial combination. PMID:27664282

  7. The nucleotide sequence of the amiE gene of Pseudomonas aeruginosa.

    PubMed

    Brammar, W J; Charles, I G; Matfield, M; Liu, C P; Drew, R E; Clarke, P H

    1987-05-11

    The nucleotide sequence of the amiE gene, encoding the aliphatic amidase of Pseudomonas aeruginosa, has been determined. The sequence of 1038 nucleotides shows a strong bias in favour of codons with G or C in the third position, and only 44 different codons are utilised.

  8. Lichen secondary metabolite evernic acid as potential quorum sensing inhibitor against Pseudomonas aeruginosa.

    PubMed

    Gökalsın, Barış; Sesal, Nüzhet Cenk

    2016-09-01

    Cystic Fibrosis is a genetic disease and it affects the respiratory and digestive systems. Pseudomonas aeruginosa infections in Cystic Fibrosis are presented as the main cause for high mortality and morbidity rates. Pseudomonas aeruginosa populations can regulate their virulence gene expressions via the bacterial communication system: quorum sensing. Inhibition of quorum sensing by employing quorum sensing inhibitors can leave the bacteria vulnerable. Therefore, determining natural sources to obtain potential quorum sensing inhibitors is essential. Lichens have ethnobotanical value for their medicinal properties and it is possible that their secondary metabolites have quorum sensing inhibitor properties. This study aims to investigate an alternative treatment approach by utilizing lichen secondary metabolite evernic acid to reduce the expressions of Pseudomonas aeruginosa virulence factors by inhibiting quorum sensing. For this purpose, fluorescent monitor strains were utilized for quorum sensing inhibitor screens and quantitative reverse-transcriptase PCR analyses were conducted for comparison. Results indicate that evernic acid is capable of inhibiting Pseudomonas aeruginosa quorum sensing systems. PMID:27465850

  9. Complete Genome Sequence of Pseudomonas aeruginosa Phage-Resistant Variant PA1RG

    PubMed Central

    Li, Gang; Lu, Shuguang; Shen, Mengyu; Le, Shuai; Tan, Yinling; Li, Ming; Zhao, Xia; Wang, Jing; Shen, Wei; Guo, Keke; Yang, Yuhui; Zhu, Hongbin; Li, Shu; Zhu, Junmin; Rao, Xiancai

    2016-01-01

    Bacteria have evolved several defense systems against phage predation. Here, we report the 6,500,439-bp complete genome sequence of the Pseudomonas aeruginosa phage-resistant variant PA1RG. Single-molecule real-time (SMRT) sequencing and de novo assembly revealed a single contig with 320-fold sequence coverage. PMID:26893434

  10. CHARACTERIZATION OF PB2+ UPTAKE AND SEQUESTRATION IN PSEUDOMONAS AERUGINOSA, CHL004, LEAD

    EPA Science Inventory

    In laboratory studies, the soil isolate Pseudomonas aeruginosa CHL004 has been found to concentrate Pb2+ in the cytoplasm by formation of particles that contain Pb2+ and phosphorus. Upon examination of many particles using x-ray diffraction, we have found that the product formed ...

  11. CHARACTERIZATION OF PB2+ UPTAKE AND SEQUESTRATION IN PSEUDOMONAS AERUGINOSA CHL004

    EPA Science Inventory

    In laboratory studies, the soil isolate Pseudomonas aeruginosa CHL004 (Vesper et al 1996) has been found to concentrated Pb2+ in the cytoplasm by formation of particles that contain Pb2+ and phosphorus. Upon examination of the washed lyophilized cells grown in the presence of lea...

  12. [Formation of volatile substances during destruction of polymers by Pseudomonas aeruginosa].

    PubMed

    Novikova, N D; Zaloguev, S N

    1985-01-01

    The effect of biodestruction of paint-and-varnish coatings on the formation and evolution of toxic substances was studied. It was found that the multiplication of Pseudomonas aeruginosa on epoxide resins (EP-255 ++ EP-525/AK-070) modified the evolution of gases: that of acetone and n-butanone increased and evolution of xylene and ethyl benzene isomers decreased.

  13. Draft Genome Sequence of a Pseudomonas aeruginosa Strain Able To Decompose N,N-Dimethyl Formamide

    PubMed Central

    Yan, Ming; Xu, Lin; Wei, Li; Zhang, Liting

    2016-01-01

    Pseudomonas aeruginosa is a Gram-negative bacterium, which uses a variety of organic chemicals as carbon sources. Here, we report the genome sequence of the Cu1510 isolate from wastewater containing a high concentration of N,N-dimethyl formamide. PMID:26847883

  14. Complete Genome Sequence of Pseudomonas aeruginosa Phage-Resistant Variant PA1RG.

    PubMed

    Li, Gang; Lu, Shuguang; Shen, Mengyu; Le, Shuai; Tan, Yinling; Li, Ming; Zhao, Xia; Wang, Jing; Shen, Wei; Guo, Keke; Yang, Yuhui; Zhu, Hongbin; Li, Shu; Zhu, Junmin; Rao, Xiancai; Hu, Fuquan

    2016-01-01

    Bacteria have evolved several defense systems against phage predation. Here, we report the 6,500,439-bp complete genome sequence of the Pseudomonas aeruginosa phage-resistant variant PA1RG. Single-molecule real-time (SMRT) sequencing and de novo assembly revealed a single contig with 320-fold sequence coverage. PMID:26893434

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-05-01

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

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

    PubMed

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

    2016-03-01

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

  18. Cloning of Escherichia coli and Pseudomonas aeruginosa phosphomannose isomerase genes and their expression in alginate-negative mutants of Pseudomonas aeruginosa.

    PubMed Central

    Darzins, A; Nixon, L L; Vanags, R I; Chakrabarty, A M

    1985-01-01

    The phosphomannose isomerase (pmi) gene of Escherichia coli was cloned on a broad-host-range cosmid vector and expressed in Pseudomonas aeruginosa at a low level. Plasmid pAD3, which harbors the E. coli pmi gene, contains a 6.2-kilobase-pair HindIII fragment derived from the chromosome of E. coli. Subcloning produced plasmids carrying the 1.5-kilobase-pair HindIII-HpaI subfragment of pAD3 that restored alginic acid production in a nonmucoid, alginate-negative mutant of P. aeruginosa. This fragment also complemented mannose-negative, phosphomannose isomerase-negative mutants of E. coli and showed no homology by DNA-DNA hybridization to P. aeruginosa chromosomal DNA. By using a BamHI constructed cosmid clone bank of the stable alginate producing strain 8830, we have been able to isolate a recombinant plasmid of P. aeruginosa origin that also restores alginate production in the alginate-negative mutant. This new recombinant plasmid, designated pAD4, contained a 9.9-kilobase-pair EcoRI-BamHI fragment with the ability to restore alginate synthesis in the alginate-negative P. aeruginosa. This fragment showed no homology to E. coli chromosomal DNA or to plasmid pAD3. Both mucoid and nonmucoid strains of P. aeruginosa had no detectable levels of phosphomannose isomerase activity as measured by mannose 6-phosphate-to-fructose 6-phosphate conversion. However, P. aeruginosa strains harboring the cloned pmi gene of E. coli contained measurable levels of phosphomannose isomerase activity as evidenced by examining the conversion of mannose 6-phosphate to fructose 6-phosphate. Images PMID:3918000

  19. Pseudomonas aeruginosa acquisition on an intensive care unit: relationship between antibiotic selective pressure and patients' environment

    PubMed Central

    2011-01-01

    Introduction The purpose of this study was to investigate the relationship among Pseudomonas aeruginosa acquisition on the intensive care unit (ICU), environmental contamination and antibiotic selective pressure against P. aeruginosa. Methods An open, prospective cohort study was carried out in a 16-bed medical ICU where P. aeruginosa was endemic. Over a six-month period, all patients without P. aeruginosa on admission and with a length of stay >72 h were included. Throat, nasal, rectal, sputum and urine samples were taken on admission and at weekly intervals and screened for P. aeruginosa. All antibiotic treatments were recorded daily. Environmental analysis included weekly tap water specimen culture and the presence of other patients colonized with P. aeruginosa. Results A total of 126 patients were included, comprising 1,345 patient-days. Antibiotics were given to 106 patients (antibiotic selective pressure for P. aeruginosa in 39). P. aeruginosa was acquired by 20 patients (16%) and was isolated from 164/536 environmental samples (31%). Two conditions were independently associated with P. aeruginosa acquisition by multivariate analysis: (i) patients receiving ≥3 days of antibiotic selective pressure together with at least one colonized patient on the same ward on the previous day (odds ratio (OR) = 10.3 ((% confidence interval (CI): 1.8 to 57.4); P = 0.01); and (ii) presence of an invasive device (OR = 7.7 (95% CI: 2.3 to 25.7); P = 0.001). Conclusions Specific interaction between both patient colonization pressure and selective antibiotic pressure is the most relevant factor for P. aeruginosa acquisition on an ICU. This suggests that combined efforts are needed against both factors to decrease colonization with P. aeruginosa. PMID:21306623

  20. Candida albicans Inhibits Pseudomonas aeruginosa Virulence through Suppression of Pyochelin and Pyoverdine Biosynthesis.

    PubMed

    Lopez-Medina, Eduardo; Fan, Di; Coughlin, Laura A; Ho, Evi X; Lamont, Iain L; Reimmann, Cornelia; Hooper, Lora V; Koh, Andrew Y

    2015-08-01

    Bacterial-fungal interactions have important physiologic and medical ramifications, but the mechanisms of these interactions are poorly understood. The gut is host to trillions of microorganisms, and bacterial-fungal interactions are likely to be important. Using a neutropenic mouse model of microbial gastrointestinal colonization and dissemination, we show that the fungus Candida albicans inhibits the virulence of the bacterium Pseudomonas aeruginosa by inhibiting P. aeruginosa pyochelin and pyoverdine gene expression, which plays a critical role in iron acquisition and virulence. Accordingly, deletion of both P. aeruginosa pyochelin and pyoverdine genes attenuates P. aeruginosa virulence. Heat-killed C. albicans has no effect on P. aeruginosa, whereas C. albicans secreted proteins directly suppress P. aeruginosa pyoverdine and pyochelin expression and inhibit P. aeruginosa virulence in mice. Interestingly, suppression or deletion of pyochelin and pyoverdine genes has no effect on P. aeruginosa's ability to colonize the GI tract but does decrease P. aeruginosa's cytotoxic effect on cultured colonocytes. Finally, oral iron supplementation restores P. aeruginosa virulence in P. aeruginosa and C. albicans colonized mice. Together, our findings provide insight into how a bacterial-fungal interaction can modulate bacterial virulence in the intestine. Previously described bacterial-fungal antagonistic interactions have focused on growth inhibition or colonization inhibition/modulation, yet here we describe a novel observation of fungal-inhibition of bacterial effectors critical for virulence but not important for colonization. These findings validate the use of a mammalian model system to explore the complexities of polymicrobial, polykingdom infections in order to identify new therapeutic targets for preventing microbial disease. PMID:26313907

  1. Pseudomonas fluorescens CHA0 produces enantio-pyochelin, the optical antipode of the Pseudomonas aeruginosa siderophore pyochelin.

    PubMed

    Youard, Zeb A; Mislin, Gaëtan L A; Majcherczyk, Paul A; Schalk, Isabelle J; Reimmann, Cornelia

    2007-12-01

    The siderophore pyochelin is made by a thiotemplate mechanism from salicylate and two molecules of cysteine. In Pseudomonas aeruginosa, the first cysteine residue is converted to its D-isoform during thiazoline ring formation whereas the second cysteine remains in its L-configuration, thus determining the stereochemistry of the two interconvertible pyochelin diastereoisomers as 4'R, 2''R, 4''R (pyochelin I) and 4'R, 2''S, 4''R (pyochelin II). Pseudomonas fluorescens CHA0 was found to make a different stereoisomeric mixture, which promoted growth under iron limitation in strain CHA0 and induced the expression of its biosynthetic genes, but was not recognized as a siderophore and signaling molecule by P. aeruginosa. Reciprocally, pyochelin promoted growth and induced pyochelin gene expression in P. aeruginosa, but was not functional in P. fluorescens. The structure of the CHA0 siderophore was determined by mass spectrometry, thin-layer chromatography, NMR, polarimetry, and chiral HPLC as enantio-pyochelin, the optical antipode of the P. aeruginosa siderophore pyochelin. Enantio-pyochelin was chemically synthesized and confirmed to be active in CHA0. Its potential biosynthetic pathway in CHA0 is discussed. PMID:17938167

  2. Bilateral Granulomatous and Fibrinoheterophilic Otitis Interna due to Pseudomonas aeruginosa in a Captive Little Bustard ( Tetrax tetrax ).

    PubMed

    Scala, Christopher; Langlois, Isabelle; Lemberger, Karin

    2015-06-01

    A captive juvenile little bustard ( Tetrax tetrax ) was presented for acute onset of right head tilt and right circling. The bird failed to respond to supportive care and systemic antibiotic therapy. A bilateral granulomatous and fibrinoheterophilic otitis interna due to Pseudomonas aeruginosa was diagnosed postmortem by histopathologic examination and bacterial culture. In bustards, Pseudomonas species have been documented in the normal bacterial flora of the oropharynx and are frequently reported in upper respiratory tract infections. This is the first report of a peripheral vestibular syndrome due to P aeruginosa otitis interna in a bustard species. Pseudomonas aeruginosa should be included as a possible cause of otitis and peripheral vestibular syndrome in bustards.

  3. Comparison of Flagellin Genes from Clinical and Environmental Pseudomonas aeruginosa Isolates

    PubMed Central

    Morgan, J. Alun W.; Bellingham, Nessa F.; Winstanley, Craig; Ousley, Margaret A.; Hart, C. Anthony; Saunders, Jon R.

    1999-01-01

    Pseudomonas aeruginosa, an important opportunistic pathogen, was isolated from environmental samples and compared to clinically derived strains. While P. aeruginosa was isolated readily from an experimental mushroom-growing unit, it was found only rarely in other environmental samples. A flagellin gene PCR-restriction fragment length polymorphism analysis of the isolates revealed that environmental and clinical P. aeruginosa strains are not readily distinguishable. The variation in the central regions of the flagellin genes of seven of the isolates was investigated further. The strains used included two strains with type a genes (998 bp), four strains with type b genes (1,258 bp), and one strain, K979, with a novel flagellin gene (2,199 bp). The route by which flagellin gene variation has occurred in P. aeruginosa is discussed. PMID:10049879

  4. Dissemination of high-risk clones of extensively drug-resistant Pseudomonas aeruginosa in colombia.

    PubMed

    Correa, Adriana; Del Campo, Rosa; Perenguez, Marcela; Blanco, Victor M; Rodríguez-Baños, Mercedes; Perez, Federico; Maya, Juan J; Rojas, Laura; Cantón, Rafael; Arias, Cesar A; Villegas, Maria V

    2015-04-01

    The ability of Pseudomonas aeruginosa to develop resistance to most antimicrobials represents an important clinical threat worldwide. We report the dissemination in several Colombian hospitals of two predominant lineages of extensively drug-resistant (XDR) carbapenemase-producing P. aeruginosa strains. These lineages belong to the high-risk clones sequence type 111 (ST111) and ST235 and harbor blaVIM-2 on a class 1 integron and blaKPC-2 on a Tn4401 transposon, respectively. Additionally, P. aeruginosa ST1492, a novel single-locus variant of ST111, was identified. Clonal dissemination and the presence of mobile genetic elements likely explain the successful spread of XDR P. aeruginosa strains in Colombia. PMID:25605362

  5. Phage-antibiotic synergism: a possible approach to combatting Pseudomonas aeruginosa.

    PubMed

    Knezevic, Petar; Curcin, Sanja; Aleksic, Verica; Petrusic, Milivoje; Vlaski, Ljiljana

    2013-01-01

    Pseudomonas aeruginosa is a highly resistant opportunistic pathogen and an important etiological agent of various types of infections. During the last decade, P. aeruginosa phages have been extensively examined as alternative antimicrobial agents. The aim of the study was to determine antimicrobial effectiveness of combining subinhibitory concentrations of gentamicin, ceftriaxone, ciprofloxacin or polymyxin B with P. aeruginosa-specific bacteriophages belonging to families Podoviridae and Siphoviridae. The time-kill curve method showed that a combination of bacteriophages and subinhibitory concentrations of ceftriaxone generally reduced bacterial growth, and synergism was proven for a Siphoviridae phage σ-1 after 300 min of incubation. The detected alteration in morphology after ceftriaxone application, resulting in cell elongation, along with its specific mode of action, seemed to be a necessary but was not a sufficient reason for phage-antibiotic synergism. The phenomenon offers an opportunity for future development of treatment strategies for potentially lethal infections caused by P. aeruginosa.

  6. Pseudomonas aeruginosa Diversification during Infection Development in Cystic Fibrosis Lungs-A Review.

    PubMed

    Sousa, Ana Margarida; Pereira, Maria Olívia

    2014-01-01

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

  7. Cloning and analysis of the rnc-era-recO operon from Pseudomonas aeruginosa.

    PubMed

    Powell, B; Peters, H K; Nakamura, Y; Court, D

    1999-08-01

    The rnc operon from Pseudomonas aeruginosa has been cloned and characterized. The three genes comprising this operon, rnc, era, and recO, are arranged similarly to those in some other gram-negative bacteria. Multicopy plasmids carrying the rnc operon of P. aeruginosa functionally complement mutations of the rnc, era, and recO genes in Escherichia coli. In particular, the P. aeruginosa era homolog rescues the conditional lethality of era mutants in E. coli, and the presumptive protein has 60% identity with the Era of E. coli. We discuss these data and evidence suggesting that a GTPase previously purified from P. aeruginosa and designated Pra is not an Era homolog. PMID:10438789

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

    PubMed Central

    Sousa, Ana Margarida; Pereira, Maria Olívia

    2014-01-01

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

  9. Pseudomonas aeruginosa forms biofilms in acute infection independent of cell-to-cell signaling.

    PubMed

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

    2007-08-01

    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 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 strains formed similar biofilms in vivo. Our findings demonstrate that P. aeruginosa forms biofilms on specific host tissues independently of QS.

  10. A study on the effect of Pseudomonas aeruginosa in semen on bovine fertility.

    PubMed Central

    Eaglesome, M D; Garcia, M M; Bielanski, A B

    1995-01-01

    Two experiments were done to demonstrate whether the presence of Pseudomonas aeruginosa in bovine semen could affect fertilization and/or early embryonic development. In the first experiment, superovulated heifers were inseminated with semen naturally contaminated with P. aeruginosa (ADRI 102) or clean semen and seven day-old embryos were collected nonsurgically. The endometrium of treated heifers appeared more sensitive to the flush procedures. In experiment 2, heifers were inseminated at synchronized estrus with semen experimentally contaminated with P. aeruginosa (ADRI 102) and processed in the same way as commercial semen with antibiotics (gentamicin, lincomycin, spectinomycin and tylosin) or processed without antibiotics added. Embryos were recovered at slaughter seven days later. In general, there was no significant reduction in fertility or development of embryos in vitro as a result of relatively high numbers of P. aeruginosa in bovine semen. PMID:7704848

  11. FvbA is required for vibriobactin utilization in Pseudomonas aeruginosa.

    PubMed

    Elias, Sivan; Degtyar, Elena; Banin, Ehud

    2011-07-01

    Bacteria acquire iron through a highly specific mechanism involving iron-chelating molecules termed siderophores. The Gram-negative bacterium Pseudomonas aeruginosa can utilize siderophores produced by other micro-organisms to facilitate iron uptake. Here we show that a P. aeruginosa strain deficient in siderophore production can use the Vibrio cholerae siderophore vibriobactin as an iron source. In addition, we identified a P. aeruginosa gene, PA4156 (fvbA), encoding a protein highly homologous to the V. cholerae vibriobactin receptor (ViuA). A P. aeruginosa mutant in the two endogenous siderophores (pyoverdine and pyochelin) and in fvbA was unable to utilize vibriobactin as an iron source. Additionally, preliminary analyses revealed the involvement of vibriobactin, Fur protein and an IclR-type regulator, FvbR (PA4157), in fvbA regulation. PMID:21546589

  12. Dissemination of High-Risk Clones of Extensively Drug-Resistant Pseudomonas aeruginosa in Colombia

    PubMed Central

    del Campo, Rosa; Perenguez, Marcela; Blanco, Victor M.; Rodríguez-Baños, Mercedes; Perez, Federico; Maya, Juan J.; Rojas, Laura; Cantón, Rafael; Arias, Cesar A.; Villegas, Maria V.

    2015-01-01

    The ability of Pseudomonas aeruginosa to develop resistance to most antimicrobials represents an important clinical threat worldwide. We report the dissemination in several Colombian hospitals of two predominant lineages of extensively drug-resistant (XDR) carbapenemase-producing P. aeruginosa strains. These lineages belong to the high-risk clones sequence type 111 (ST111) and ST235 and harbor blaVIM-2 on a class 1 integron and blaKPC-2 on a Tn4401 transposon, respectively. Additionally, P. aeruginosa ST1492, a novel single-locus variant of ST111, was identified. Clonal dissemination and the presence of mobile genetic elements likely explain the successful spread of XDR P. aeruginosa strains in Colombia. PMID:25605362

  13. Use of the paraffin wax baiting system for identification of Pseudomonas aeruginosa clinical isolates.

    PubMed

    Massengale, A R; Ollar, R A; Giordano, S J; Felder, M S; Aronoff, S C

    1999-11-01

    Pseudomonas aeruginosa is the primary pathogen among the Pseudomonads and is known for its minimal nutritional requirements, capacity to use paraffin as a sole carbon source, and biofilm formation. Because the ability of Pseudomonads to grow on paraffin is not commonly found among human pathogens and the primary Pseudomonas human pathogen is P. aeruginosa, we studied the adaptation of the paraffin baiting system for the growth and identification of clinical isolates of P. aeruginosa. We also studied the effectiveness of combining a fluorescence assay measuring fluorescein (pyoverdin) production and oxidase test with the paraffin baiting assay for P. aeruginosa speciation. Strains were tested for the capacity to use paraffin as a sole carbon source using the paraffin baiting system with Czapek's minimal salt medium. Of 111 P. aeruginosa clinical isolates tested for using paraffin as a sole carbon source, 45% exhibited growth on paraffin at 24 h and 76.6% exhibited growth on paraffin at 48 h. The ability of the reference strains and clinical isolates were then tested for their ability to associate with the paraffin slide in the presence of an additional carbon source. Of 111 P. aeruginosa clinical isolates tested, 85 strains (76.6%), and 102 (93%) were associated with the paraffin surface at 24 and 48 h. We successfully combined fluorescence and oxidase assays with the paraffin baiting system for identification of P. aeruginosa. The simple and inexpensive paraffin baiting system is a useful method for the identification and study of P. aeruginosa suitable for both the clinical and research laboratory.

  14. Pseudomonas aeruginosa in Cystic Fibrosis Patients With G551D-CFTR Treated With Ivacaftor

    PubMed Central

    Heltshe, Sonya L.; Mayer-Hamblett, Nicole; Burns, Jane L.; Khan, Umer; Baines, Arthur; Ramsey, Bonnie W.; Rowe, Steven M.

    2015-01-01

    Background. Ivacaftor improves outcomes in cystic fibrosis (CF) patients with the G551D mutation; however, effects on respiratory microbiology are largely unknown. This study examines changes in CF respiratory pathogens with ivacaftor and correlates them with baseline characteristics and clinical response. Methods. The G551D Observational Study enrolled a longitudinal observational cohort of US patients with CF aged 6 years and older with at least 1 copy of the G551D mutation. Results were linked with retrospective and prospective culture data in the US Cystic Fibrosis Foundation's National Patient Registry. Pseudomonas aeruginosa infection category in the year before and year after ivacaftor was compared and correlated with clinical findings. Results. Among 151 participants prescribed ivacaftor, 29% (26/89) who were culture positive for P. aeruginosa the year prior to ivacaftor use were culture negative the year following treatment; 88% (52/59) of those P. aeruginosa free remained uninfected. The odds of P. aeruginosa positivity in the year after ivacaftor compared with the year prior were reduced by 35% (odds ratio [OR], 0.65; P < .001). Ivacaftor was also associated with reduced odds of mucoid P. aeruginosa (OR, 0.77; P = .013) and Aspergillus (OR, 0.47; P = .039), but not Staphylococcus aureus or other common CF pathogens. Patients with intermittent culture positivity and higher forced expiratory volume in 1 second (FEV1) were most likely to turn culture negative. Reduction in P. aeruginosa was not associated with change in FEV1, body mass index, or hospitalizations. Conclusions. Pseudomonas aeruginosa culture positivity was significantly reduced following ivacaftor treatment. Efficacious CFTR modulation may contribute to lower frequency of culture positivity for P. aeruginosa and other respiratory pathogens, particularly in patients with less established disease. PMID:25425629

  15. Outbreaks of multidrug-resistant Pseudomonas aeruginosa in community hospitals in Japan.

    PubMed

    Sekiguchi, Jun-Ichiro; Asagi, Tsukasa; Miyoshi-Akiyama, Tohru; Kasai, Atsushi; Mizuguchi, Yukie; Araake, Minako; Fujino, Tomoko; Kikuchi, Hideko; Sasaki, Satoru; Watari, Hajime; Kojima, Tadashi; Miki, Hiroshi; Kanemitsu, Keiji; Kunishima, Hiroyuki; Kikuchi, Yoshihiro; Kaku, Mitsuo; Yoshikura, Hiroshi; Kuratsuji, Tadatoshi; Kirikae, Teruo

    2007-03-01

    We previously reported an outbreak in a neurosurgery ward of catheter-associated urinary tract infection with multidrug-resistant (MDR) Pseudomonas aeruginosa strain IMCJ2.S1, carrying the 6'-N-aminoglycoside acetyltransferase gene [aac(6')-Iae]. For further epidemiologic studies, 214 clinical isolates of MDR P. aeruginosa showing resistance to imipenem (MIC >or= 16 microg/ml), amikacin (MIC >or= 64 microg/ml), and ciprofloxacin (MIC >or= 4 microg/ml) were collected from 13 hospitals in the same prefecture in Japan. We also collected 70 clinical isolates of P. aeruginosa that were sensitive to one or more of these antibiotics and compared their characteristics with those of the MDR P. aeruginosa isolates. Of the 214 MDR P. aeruginosa isolates, 212 (99%) were serotype O11. We developed a loop-mediated isothermal amplification (LAMP) assay and a slide agglutination test for detection of the aac(6')-Iae gene and the AAC(6')-Iae protein, respectively. Of the 212 MDR P. aeruginosa isolates, 212 (100%) and 207 (98%) were positive in the LAMP assay and in the agglutination test, respectively. Mutations of gyrA and parC genes resulting in amino acid substitutions were detected in 213 of the 214 MDR P. aeruginosa isolates (99%). Of the 214 MDR P. aeruginosa isolates, 212 showed pulsed-field gel electrophoresis patterns with >or=70% similarity to that of IMCJ2.S1 and 83 showed a pattern identical to that of IMCJ2.S1, indicating that clonal expansion of MDR P. aeruginosa occurred in community hospitals in this area. The methods developed in this study to detect aac(6')-Iae were rapid and effective in diagnosing infections caused by various MDR P. aeruginosa clones.

  16. Activation of the lectin pathway of complement in experimental human keratitis with Pseudomonas aeruginosa

    PubMed Central

    Osthoff, Michael; Brown, Karl D.; Kong, David C.M.; Daniell, Mark

    2014-01-01

    Purpose Pseudomonas aeruginosa (P. aeruginosa) microbial keratitis (MK) is a sight-threatening disease. Previous animal studies have identified an important contribution of the complement system to the clearance of P. aeruginosa infection of the cornea. Mannose-binding lectin (MBL), a pattern recognition receptor of the lectin pathway of complement, has been implicated in the host defense against P. aeruginosa. However, studies addressing the role of the lectin pathway in P. aeruginosa MK are lacking. Hence, we sought to determine the activity of the lectin pathway in human MK caused by P. aeruginosa. Methods Primary human corneal epithelial cells (HCECs) from cadaveric donors were exposed to two different P. aeruginosa strains. Gene expression of interleukin (IL)-6, IL-8, MBL, and other complement proteins was determined by reverse transcription-polymerase chain reaction (RT–PCR) and MBL synthesis by enzyme-linked immunosorbent assay and intracellular flow cytometry. Results MBL gene expression was not detected in unchallenged HCECs. Exposure of HCECs to P. aeruginosa resulted in rapid induction of the transcriptional expression of MBL, IL-6, and IL-8. In addition, expression of several complement proteins of the classical and lectin pathways, but not the alternative pathway, were upregulated after 5 h of challenge, including MBL-associated serine protease 1. However, MBL protein secretion was not detectable 18 h after challenge with P. aeruginosa. Conclusions MK due to P. aeruginosa triggers activation of MBL and the lectin pathway of complement. However, the physiologic relevance of this finding is unclear, as corresponding MBL oligomer production was not observed. PMID:24426774

  17. Direct measurement of efflux in Pseudomonas aeruginosa using an environment-sensitive fluorescent dye.

    PubMed

    Iyer, Ramkumar; Erwin, Alice L

    2015-01-01

    Resistance-Nodulation-Division (RND) family pumps AcrB and MexB are the major efflux routes in Escherichia coli and Pseudomonas aeruginosa respectively. Fluorescent environment-sensitive dyes provide a means to study efflux pump function in live bacterial cells in real-time. Recently, we demonstrated the utility of this approach using the dye Nile Red to quantify AcrB-mediated efflux and measured the ability of antibiotics and other efflux pump substrates to compete with efflux of Nile Red, independent of antibacterial activity. Here, we extend this method to P. aeruginosa and describe a novel application that permits the comparison and rank-ordering of bacterial strains by their inherent efflux potential. We show that glucose and l-malate re-energize Nile Red efflux in P. aeruginosa, and we highlight differences in the glucose dependence and kinetics of efflux between P. aeruginosa and E. coli. We quantify the differences in efflux among a set of P. aeruginosa laboratory strains, which include PAO1, the hyper-sensitive strain ATCC 35151 and its parent, ATCC 12055. Efflux of Nile Red in P. aeruginosa is mediated by MexAB-OprM and is slower than in E. coli. In conclusion, we describe an efflux measurement tool for use in antibacterial drug discovery and basic research on P. aeruginosa efflux pumps.

  18. Environmental survivability and surface sampling efficiencies for Pseudomonas aeruginosa on various fomites.

    PubMed

    Jones, Tia M; Lutz, Eric A

    2014-05-01

    The study described in this article evaluated surface survivability of culturable Pseudomonas aeruginosa by time and type (glass, stainless steel, and laminate) using two sampling techniques: contact plates and surface swabs. Recovery of P. aeruginosa decreased logarithmically over time and varied by surface type. P. aeruginosa survival averaged 3.75, 5.75, and 6.75 hours on laminate, glass, and stainless steel, respectively. Culturable P. aeruginosa loss on stainless steel and glass were not different (p > .05); however, laminate had significantly greater loss at each time point than either glass or stainless (p < .05). A comparison of surface swab and contact plate collection efficiencies found no significant difference for laminate surfaces. Swabs, however, had a higher collection efficiency than contact plates (p < .05). For the first time, the authors report P. aeruginosa mean survival time of 3.75-6.75 hours on clinically relevant surfaces, with P. aeruginosa on stainless steel surviving the longest. Their data also indicate that culturable surface sampling appears to most accurately represent actual P. aeruginosa surface loading when swab sampling is used.

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

    PubMed Central

    Cornelis, Pierre; Dingemans, Jozef

    2013-01-01

    Pseudomonas aeruginosa is a Gram-negative γ-Proteobacterium which is known for its capacity to colonize various niches, including some invertebrate and vertebrate hosts, making it one of the most frequent bacteria causing opportunistic infections. P. aeruginosa is able to cause acute as well as chronic infections and it uses different colonization and virulence factors to do so. Infections range from septicemia, urinary infections, burn wound colonization, and chronic colonization of the lungs of cystic fibrosis patients. Like the vast majority of organisms, P. aeruginosa needs iron to sustain growth. P. aeruginosa utilizes different strategies to take up iron, depending on the type of infection it causes. Two siderophores are produced by this bacterium, pyoverdine and pyochelin, characterized by high and low affinities for iron respectively. P. aeruginosa is also able to utilize different siderophores from other microorganisms (siderophore piracy). It can also take up heme from hemoproteins via two different systems. Under microaerobic or anaerobic conditions, P. aeruginosa is also able to take up ferrous iron via its Feo system using redox-cycling phenazines. Depending on the type of infection, P. aeruginosa can therefore adapt by switching from one iron uptake system to another as we will describe in this short review. PMID:24294593

  20. Efficacy of the Novel Antibiotic POL7001 in Preclinical Models of Pseudomonas aeruginosa Pneumonia.

    PubMed

    Cigana, Cristina; Bernardini, Francesca; Facchini, Marcella; Alcalá-Franco, Beatriz; Riva, Camilla; De Fino, Ida; Rossi, Alice; Ranucci, Serena; Misson, Pauline; Chevalier, Eric; Brodmann, Maj; Schmitt, Michel; Wach, Achim; Dale, Glenn E; Obrecht, Daniel; Bragonzi, Alessandra

    2016-08-01

    The clinical development of antibiotics with a new mode of action combined with efficient pulmonary drug delivery is a priority against untreatable Pseudomonas aeruginosa lung infections. POL7001 is a macrocycle antibiotic belonging to the novel class of protein epitope mimetic (PEM) molecules with selective and potent activity against P. aeruginosa We investigated ventilator-associated pneumonia (VAP) and cystic fibrosis (CF) as indications of the clinical potential of POL7001 to treat P. aeruginosa pulmonary infections. MICs of POL7001 and comparators were measured for reference and clinical P. aeruginosa strains. The therapeutic efficacy of POL7001 given by pulmonary administration was evaluated in murine models of P. aeruginosa acute and chronic pneumonia. POL7001 showed potent in vitro activity against a large panel of P. aeruginosa isolates from CF patients, including multidrug-resistant (MDR) isolates with adaptive phenotypes such as mucoid or hypermutable phenotypes. The efficacy of POL7001 was demonstrated in both wild-type and CF mice. In addition to a reduced bacterial burden in the lung, POL7001-treated mice showed progressive body weight recovery and reduced levels of inflammatory markers, indicating an improvement in general condition. Pharmacokinetic studies indicated that POL7001 reached significant concentrations in the lung after pulmonary administration, with low systemic exposure. These results support the further evaluation of POL7001 as a novel therapeutic agent for the treatment of P. aeruginosa pulmonary infections.

  1. Distribution and Inhibition of Liposomes on Staphylococcus aureus and Pseudomonas aeruginosa Biofilm

    PubMed Central

    Dong, Dong; Thomas, Nicky; Thierry, Benjamin; Vreugde, Sarah; Prestidge, Clive A.; Wormald, Peter-John

    2015-01-01

    Background Staphylococcus aureus and Pseudomonas aeruginosa are major pathogens in chronic rhinosinusitis (CRS) and their biofilms have been associated with poorer postsurgical outcomes. This study investigated the distribution and anti-biofilm effect of cationic (+) and anionic (-) phospholipid liposomes with different sizes (unilamellar and multilamellar vesicle, ULV and MLV respectively) on S. aureus and P. aeruginosa biofilms. Method Specific biofilm models for S. aureus ATCC 25923 and P. aeruginosa ATCC 15692 were established. Liposomal distribution was determined by observing SYTO9 stained biofilm exposed to DiI labeled liposomes using confocal scanning laser microscopy, followed by quantitative image analysis. The anti-biofilm efficacy study was carried out by using the alamarBlue assay to test the relative viability of biofilm treated with various liposomes for 24 hours and five minutes. Results The smaller ULVs penetrated better than larger MLVs in both S. aureus and P. aeruginosa biofilm. Except that +ULV and –ULV displayed similar distribution in S. aureus biofilm, the cationic liposomes adhered better than their anionic counterparts. Biofilm growth was inhibited at 24-hour and five-minute exposure time, although the decrease of viability for P. aeruginosa biofilm after liposomal treatment did not reach statistical significance. Conclusion The distribution and anti-biofilm effects of cationic and anionic liposomes of different sizes differed in S. aureus and P. aeruginosa biofilms. Reducing the liposome size and formulating liposomes as positively charged enhanced the penetration and inhibition of S. aureus and P. aeruginosa biofilms. PMID:26125555

  2. Inhibition of biofilm formation by Camelid single-domain antibodies against the flagellum of Pseudomonas aeruginosa.

    PubMed

    Adams, Hendrik; Horrevoets, Wannie M; Adema, Simon M; Carr, Hannah E V; van Woerden, Richard E; Koster, Margot; Tommassen, Jan

    2014-09-30

    Pseudomonas aeruginosa is a leading cause of hospital-acquired infections in patients with compromised host defense mechanisms, including burn wound victims. In addition to its intrinsic resistance against most antibiotics, P. aeruginosa has the ability to form biofilms adhering to biotic or abiotic surfaces. These factors make treatment of P. aeruginosa infections complicated and demand new therapies and drugs. The flagellum of P. aeruginosa plays an important role in cell-cell and cell-surface interactions during the first stage of biofilm formation. In this study, we describe the selection of monoclonal anti-flagellin single-domain antibodies (VHHs) derived from the Camelid heavy-chain antibody repertoire of a llama immunized with P. aeruginosa antigens. The anti-flagellin VHHs could be produced efficiently in Saccharomyces cerevisiae, and surface plasmon resonance experiments demonstrated that they have apparent affinities in the nanomolar range. Functional screens showed that the anti-flagellin VHHs are capable of inhibiting P. aeruginosa from swimming and that they prevent biofilm formation in an in vitro assay. These data open doors for the development of novel methods for the prevention of P. aeruginosa-related infections.

  3. Pseudomonas aeruginosa uses T3SS to inhibit diabetic wound healing.

    PubMed

    Goldufsky, Josef; Wood, Stephen J; Jayaraman, Vijayakumar; Majdobeh, Omar; Chen, Lin; Qin, Shanshan; Zhang, Chunxiang; DiPietro, Luisa A; Shafikhani, Sasha H

    2015-01-01

    Diabetic foot ulcers are responsible for more hospitalizations than any other complication of diabetes. Bacterial infection is recognized as an important factor associated with impaired healing in diabetic ulcers. Pseudomonas aeruginosa is the most frequently detected Gram-negative pathogen in diabetic ulcers. P. aeruginosa infection has been shown to impair healing in diabetic wounds in a manner that correlates with its ability to form biofilm. While the majority of infections in diabetic ulcers are biofilm associated, 33% of infections are nonbiofilm in nature. P. aeruginosa is the most prevalent Gram-negative pathogen in all diabetic wound types, which suggests that the deleterious impact of P. aeruginosa on healing in diabetic wounds goes beyond its ability to form biofilm and likely involves other factors. The Type III Secretion System (T3SS) virulence structure is required for the pathogenesis of all P. aeruginosa clinical isolates, suggesting that it may also play a role in the inhibition of wound repair in diabetic skin ulcers. We evaluated the role of T3SS in mediating P. aeruginosa-induced tissue damage in the wounds of diabetic mice. Our data demonstrate that P. aeruginosa establishes a robust and persistent infection in diabetic wounds independent of its ability to form biofilm and causes severe wound damage in a manner that primarily depends on its T3SS.

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

    PubMed

    Cornelis, Pierre; Dingemans, Jozef

    2013-01-01

    Pseudomonas aeruginosa is a Gram-negative γ-Proteobacterium which is known for its capacity to colonize various niches, including some invertebrate and vertebrate hosts, making it one of the most frequent bacteria causing opportunistic infections. P. aeruginosa is able to cause acute as well as chronic infections and it uses different colonization and virulence factors to do so. Infections range from septicemia, urinary infections, burn wound colonization, and chronic colonization of the lungs of cystic fibrosis patients. Like the vast majority of organisms, P. aeruginosa needs iron to sustain growth. P. aeruginosa utilizes different strategies to take up iron, depending on the type of infection it causes. Two siderophores are produced by this bacterium, pyoverdine and pyochelin, characterized by high and low affinities for iron respectively. P. aeruginosa is also able to utilize different siderophores from other microorganisms (siderophore piracy). It can also take up heme from hemoproteins via two different systems. Under microaerobic or anaerobic conditions, P. aeruginosa is also able to take up ferrous iron via its Feo system using redox-cycling phenazines. Depending on the type of infection, P. aeruginosa can therefore adapt by switching from one iron uptake system to another as we will describe in this short review. PMID:24294593

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    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

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

    PubMed

    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

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

    PubMed Central

    Gruber, Jordon D.; Chen, Wei; Parnham, Stuart; Beauchesne, Kevin; Moeller, Peter; Flume, Patrick A.

    2016-01-01

    Bacteria synchronize group behaviors using quorum sensing, which is advantageous during an infection to thwart immune cell attack and resist deleterious changes in the environment. In Pseudomonas aeruginosa, the Pseudomonas quinolone signal (Pqs) quorum-sensing system is an important component of an interconnected intercellular communication network. Two alkylquinolones, 2-heptyl-4-quinolone (HHQ) and 2-heptyl-3-hydroxy-4-quinolone (PQS), activate transcriptional regulator PqsR to promote the production of quinolone signals and virulence factors. Our work focused on the most abundant quinolone produced from the Pqs system, 2,4-dihydroxyquinoline (DHQ), which was shown previously to sustain pyocyanin production and antifungal activity of P. aeruginosa. However, little is known about how DHQ affects P. aeruginosa pathogenicity. Using C. elegans as a model for P. aeruginosa infection, we found pqs mutants only able to produce DHQ maintained virulence towards the nematodes similar to wild-type. In addition, DHQ-only producing mutants displayed increased colonization of C. elegans and virulence factor production compared to a quinolone-null strain. DHQ also bound to PqsR and activated the transcription of pqs operon. More importantly, high extracellular concentration of DHQ was maintained in both aerobic and anaerobic growth. High levels of DHQ were also detected in the sputum samples of cystic fibrosis patients. Taken together, our findings suggest DHQ may play an important role in sustaining P. aeruginosa pathogenicity under oxygen-limiting conditions. PMID:26788419

  9. Identification of water-conditioned Pseudomonas aeruginosa by Raman microspectroscopy on a single cell level.

    PubMed

    Silge, Anja; Schumacher, Wilm; Rösch, Petra; Da Costa Filho, Paulo A; Gérard, Cédric; Popp, Jürgen

    2014-07-01

    The identification of Pseudomonas aeruginosa from samples of bottled natural mineral water by the analysis of subcultures is time consuming and other species of the authentic Pseudomonas group can be a problem. Therefore, this study aimed to investigate the influence of different aquatic environmental conditions (pH, mineral content) and growth phases on the cultivation-free differentiation between water-conditioned Pseudomonas spp. by applying Raman microspectroscopy. The final dataset was comprised of over 7500 single-cell Raman spectra, including the species Pseudomonas aeruginosa, P. fluorescens and P. putida, in order to prove the feasibility of the introduced approach. The collection of spectra was standardized by automated measurements of viable stained bacterial cells. The discrimination was influenced by the growth phase at the beginning of the water adaptation period and by the type of mineral water. Different combinations of the parameters were tested and they resulted in accuracies of up to 85% for the identification of P. aeruginosa from independent samples by applying chemometric analysis.

  10. Identification of water-conditioned Pseudomonas aeruginosa by Raman microspectroscopy on a single cell level.

    PubMed

    Silge, Anja; Schumacher, Wilm; Rösch, Petra; Da Costa Filho, Paulo A; Gérard, Cédric; Popp, Jürgen

    2014-07-01

    The identification of Pseudomonas aeruginosa from samples of bottled natural mineral water by the analysis of subcultures is time consuming and other species of the authentic Pseudomonas group can be a problem. Therefore, this study aimed to investigate the influence of different aquatic environmental conditions (pH, mineral content) and growth phases on the cultivation-free differentiation between water-conditioned Pseudomonas spp. by applying Raman microspectroscopy. The final dataset was comprised of over 7500 single-cell Raman spectra, including the species Pseudomonas aeruginosa, P. fluorescens and P. putida, in order to prove the feasibility of the introduced approach. The collection of spectra was standardized by automated measurements of viable stained bacterial cells. The discrimination was influenced by the growth phase at the beginning of the water adaptation period and by the type of mineral water. Different combinations of the parameters were tested and they resulted in accuracies of up to 85% for the identification of P. aeruginosa from independent samples by applying chemometric analysis. PMID:24958608

  11. Enzymatic Modification of Aminoglycoside Antibiotics: a New 6′-N-Acetylating Enzyme from a Pseudomonas aeruginosa Isolate

    PubMed Central

    Haas, M.; Biddlecome, S.; Davies, J.; Luce, C. E.; Daniels, P. J. L.

    1976-01-01

    We describe an aminoglycoside 6′-N-acetyltransferase, isolated from Pseudomonas aeruginosa, that exhibits a novel substrate profile characterized by markedly reduced activity towards butirosin and amikacin. PMID:820249

  12. AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA

    PubMed Central

    TEIXEIRA, Bertinellys; RODULFO, Hectorina; CARREÑO, Numirin; GUZMÁN, Militza; SALAZAR, Elsa; DONATO, Marcos DE

    2016-01-01

    The enzymatic modification of aminoglycosides by aminoglycoside-acetyltransferases (AAC), aminoglycoside-adenyltransferases (AAD), and aminoglycoside-phosphotransferases (APH), is the most common resistance mechanism in P. aeruginosa and these enzymes can be coded on mobile genetic elements that contribute to their dispersion. One hundred and thirty seven P. aeruginosa isolates from the University Hospital, Cumana, Venezuela (HUAPA) were evaluated. Antimicrobial susceptibility was determined by the disk diffusion method and theaac, aadB and aph genes were detected by PCR. Most of the P. aeruginosa isolates (33/137) were identified from the Intensive Care Unit (ICU), mainly from discharges (96/137). The frequency of resistant P. aeruginosaisolates was found to be higher for the aminoglycosides tobramycin and amikacin (30.7 and 29.9%, respectively). Phenotype VI, resistant to these antibiotics, was the most frequent (14/49), followed by phenotype I, resistant to all the aminoglycosides tested (12/49). The aac(6´)-Ib,aphA1 and aadB genes were the most frequently detected, and the simultaneous presence of several resistance genes in the same isolate was demonstrated. Aminoglycoside resistance in isolates ofP. aeruginosa at the HUAPA is partly due to the presence of the aac(6´)-Ib, aphA1 andaadB genes, but the high rates of antimicrobial resistance suggest the existence of several mechanisms acting together. This is the first report of aminoglycoside resistance genes in Venezuela and one of the few in Latin America. PMID:27007556

  13. AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA.

    PubMed

    Teixeira, Bertinellys; Rodulfo, Hectorina; Carreño, Numirin; Guzmán, Militza; Salazar, Elsa; De Donato, Marcos

    2016-01-01

    The enzymatic modification of aminoglycosides by aminoglycoside-acetyltransferases (AAC), aminoglycoside-adenyltransferases (AAD), and aminoglycoside-phosphotransferases (APH), is the most common resistance mechanism in P. aeruginosa and these enzymes can be coded on mobile genetic elements that contribute to their dispersion. One hundred and thirty seven P. aeruginosa isolates from the University Hospital, Cumana, Venezuela (HUAPA) were evaluated. Antimicrobial susceptibility was determined by the disk diffusion method and theaac, aadB and aph genes were detected by PCR. Most of the P. aeruginosa isolates (33/137) were identified from the Intensive Care Unit (ICU), mainly from discharges (96/137). The frequency of resistant P. aeruginosaisolates was found to be higher for the aminoglycosides tobramycin and amikacin (30.7 and 29.9%, respectively). Phenotype VI, resistant to these antibiotics, was the most frequent (14/49), followed by phenotype I, resistant to all the aminoglycosides tested (12/49). The aac(6´)-Ib,aphA1 and aadB genes were the most frequently detected, and the simultaneous presence of several resistance genes in the same isolate was demonstrated. Aminoglycoside resistance in isolates ofP. aeruginosa at the HUAPA is partly due to the presence of the aac(6´)-Ib, aphA1 andaadB genes, but the high rates of antimicrobial resistance suggest the existence of several mechanisms acting together. This is the first report of aminoglycoside resistance genes in Venezuela and one of the few in Latin America. PMID:27007556

  14. AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA.

    PubMed

    Teixeira, Bertinellys; Rodulfo, Hectorina; Carreño, Numirin; Guzmán, Militza; Salazar, Elsa; De Donato, Marcos

    2016-01-01

    The enzymatic modification of aminoglycosides by aminoglycoside-acetyltransferases (AAC), aminoglycoside-adenyltransferases (AAD), and aminoglycoside-phosphotransferases (APH), is the most common resistance mechanism in P. aeruginosa and these enzymes can be coded on mobile genetic elements that contribute to their dispersion. One hundred and thirty seven P. aeruginosa isolates from the University Hospital, Cumana, Venezuela (HUAPA) were evaluated. Antimicrobial susceptibility was determined by the disk diffusion method and theaac, aadB and aph genes were detected by PCR. Most of the P. aeruginosa isolates (33/137) were identified from the Intensive Care Unit (ICU), mainly from discharges (96/137). The frequency of resistant P. aeruginosaisolates was found to be higher for the aminoglycosides tobramycin and amikacin (30.7 and 29.9%, respectively). Phenotype VI, resistant to these antibiotics, was the most frequent (14/49), followed by phenotype I, resistant to all the aminoglycosides tested (12/49). The aac(6´)-Ib,aphA1 and aadB genes were the most frequently detected, and the simultaneous presence of several resistance genes in the same isolate was demonstrated. Aminoglycoside resistance in isolates ofP. aeruginosa at the HUAPA is partly due to the presence of the aac(6´)-Ib, aphA1 andaadB genes, but the high rates of antimicrobial resistance suggest the existence of several mechanisms acting together. This is the first report of aminoglycoside resistance genes in Venezuela and one of the few in Latin America.

  15. Comparison of plant growth-promotion with Pseudomonas aeruginosa and Bacillus subtilis in three vegetables

    PubMed Central

    Adesemoye, A.O.; Obini, M.; Ugoji, E.O.

    2008-01-01

    Our objective was to compare some plant growth promoting rhizobacteria (PGPR) properties of Bacillus subtilis and Pseudomonas aeruginosa as representatives of their two genera. Solanum lycopersicum L. (tomato), Abelmoschus esculentus (okra), and Amaranthus sp. (African spinach) were inoculated with the bacterial cultures. At 60 days after planting, dry biomass for plants treated with B. subtilis and P. aeruginosa increased 31% for tomato, 36% and 29% for okra, and 83% and 40% for African spinach respectively over the non-bacterized control. Considering all the parameters tested, there were similarities but no significant difference at P < 0.05 between the overall performances of the two organisms. PMID:24031240

  16. Wide Dissemination of Pseudomonas aeruginosa Producing β-Lactamase blaKPC-2 Gene in Colombia▿

    PubMed Central

    Cuzon, Gaelle; Naas, Thierry; Villegas, Maria-Virginia; Correa, Adriana; Quinn, John P.; Nordmann, Patrice

    2011-01-01

    Ten blaKPC-2-harboring Pseudomonas aeruginosa isolates from hospitals located in five different Colombian cities have been characterized. Isolates were multidrug resistant, belonged to five different pulsotypes, and possessed naturally chromosome-encoded blaAmpC and blaOXA-50 genes and the acquired blaKPC-2 gene. In most cases, the blaKPC-2 genes were carried by plasmids of different sizes and were associated with Tn4401b or a new structure containing only part of the Tn4401 sequence. This study revealed that several clones of P. aeruginosa producing blaKPC-2 are disseminating in Colombia. PMID:21844315

  17. Chemical Inhibition of Kynureninase Reduces Pseudomonas aeruginosa Quorum Sensing and Virulence Factor Expression.

    PubMed

    Kasper, Stephen H; Bonocora, Richard P; Wade, Joseph T; Musah, Rabi Ann; Cady, Nathaniel C

    2016-04-15

    The opportunistic pathogen Pseudomonas aeruginosa utilizes multiple quorum sensing (QS) pathways to coordinate an arsenal of virulence factors. We previously identified several cysteine-based compounds inspired by natural products from the plant Petiveria alliacea which are capable of antagonizing multiple QS circuits as well as reducing P. aeruginosa biofilm formation. To understand the global effects of such compounds on virulence factor production and elucidate their mechanism of action, RNA-seq transcriptomic analysis was performed on P. aeruginosa PAO1 exposed to S-phenyl-l-cysteine sulfoxide, the most potent inhibitor from the prior study. Exposure to this inhibitor down-regulated expression of several QS-regulated virulence operons (e.g., phenazine biosynthesis, type VI secretion systems). Interestingly, many genes that were differentially regulated pertain to the related metabolic pathways that yield precursors of pyochelin, tricarboxylic acid cycle intermediates, phenazines, and Pseudomonas quinolone signal (PQS). Activation of the MexT-regulon was also indicated, including the multidrug efflux pump encoded by mexEF-oprN, which has previously been shown to inhibit QS and pathogenicity. Deeper investigation of the metabolites involved in these systems revealed that S-phenyl-l-cysteine sulfoxide has structural similarity to kynurenine, a precursor of anthranilate, which is critical for P. aeruginosa virulence. By supplementing exogenous anthranilate, the QS-inhibitory effect was reversed. Finally, it was shown that S-phenyl-l-cysteine sulfoxide competitively inhibits P. aeruginosa kynureninase (KynU) activity in vitro and reduces PQS production in vivo. The kynurenine pathway has been implicated in P. aeruginosa QS and virulence factor expression; however, this is the first study to show that targeted inhibition of KynU affects P. aeruginosa gene expression and QS, suggesting a potential antivirulence strategy.

  18. Chemical Inhibition of Kynureninase Reduces Pseudomonas aeruginosa Quorum Sensing and Virulence Factor Expression.

    PubMed

    Kasper, Stephen H; Bonocora, Richard P; Wade, Joseph T; Musah, Rabi Ann; Cady, Nathaniel C

    2016-04-15

    The opportunistic pathogen Pseudomonas aeruginosa utilizes multiple quorum sensing (QS) pathways to coordinate an arsenal of virulence factors. We previously identified several cysteine-based compounds inspired by natural products from the plant Petiveria alliacea which are capable of antagonizing multiple QS circuits as well as reducing P. aeruginosa biofilm formation. To understand the global effects of such compounds on virulence factor production and elucidate their mechanism of action, RNA-seq transcriptomic analysis was performed on P. aeruginosa PAO1 exposed to S-phenyl-l-cysteine sulfoxide, the most potent inhibitor from the prior study. Exposure to this inhibitor down-regulated expression of several QS-regulated virulence operons (e.g., phenazine biosynthesis, type VI secretion systems). Interestingly, many genes that were differentially regulated pertain to the related metabolic pathways that yield precursors of pyochelin, tricarboxylic acid cycle intermediates, phenazines, and Pseudomonas quinolone signal (PQS). Activation of the MexT-regulon was also indicated, including the multidrug efflux pump encoded by mexEF-oprN, which has previously been shown to inhibit QS and pathogenicity. Deeper investigation of the metabolites involved in these systems revealed that S-phenyl-l-cysteine sulfoxide has structural similarity to kynurenine, a precursor of anthranilate, which is critical for P. aeruginosa virulence. By supplementing exogenous anthranilate, the QS-inhibitory effect was reversed. Finally, it was shown that S-phenyl-l-cysteine sulfoxide competitively inhibits P. aeruginosa kynureninase (KynU) activity in vitro and reduces PQS production in vivo. The kynurenine pathway has been implicated in P. aeruginosa QS and virulence factor expression; however, this is the first study to show that targeted inhibition of KynU affects P. aeruginosa gene expression and QS, suggesting a potential antivirulence strategy. PMID:26785289

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

    PubMed

    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.

  20. Solar Disinfection of Pseudomonas aeruginosa in Harvested Rainwater: A Step towards Potability of Rainwater

    PubMed Central

    Amin, Muhammad T.; Nawaz, Mohsin; Amin, Muhammad N.; Han, Mooyoung

    2014-01-01

    Efficiency of solar based disinfection of Pseudomonas aeruginosa (P. aeruginosa) in rooftop harvested rainwater was evaluated aiming the potability of rainwater. The rainwater samples were exposed to direct sunlight for about 8–9 hours and the effects of water temperature (°C), sunlight irradiance (W/m2), different rear surfaces of polyethylene terephthalate bottles, variable microbial concentrations, pH and turbidity were observed on P. aeruginosa inactivation at different weathers. In simple solar disinfection (SODIS), the complete inactivation of P. aeruginosa was obtained only under sunny weather conditions (>50°C and >700 W/m2) with absorptive rear surface. Solar collector disinfection (SOCODIS) system, used to improve the efficiency of simple SODIS under mild and weak weather, completely inactivated the P. aeruginosa by enhancing the disinfection efficiency of about 20% only at mild weather. Both SODIS and SOCODIS systems, however, were found inefficient at weak weather. Different initial concentrations of P. aeruginosa and/or Escherichia coli had little effects on the disinfection efficiency except for the SODIS with highest initial concentrations. The inactivation of P. aeruginosa increased by about 10–15% by lowering the initial pH values from 10 to 3. A high initial turbidity, adjusted by adding kaolin, adversely affected the efficiency of both systems and a decrease, about 15–25%; in inactivation of P. aeruginosa was observed. The kinetics of this study was investigated by Geeraerd Model for highlighting the best disinfection system based on reaction rate constant. The unique detailed investigation of P. aeruginosa disinfection with sunlight based disinfection systems under different weather conditions and variable parameters will help researchers to understand and further improve the newly invented SOCODIS system. PMID:24595188

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

    PubMed

    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

  2. Insights into Mechanisms and Proteomic Characterisation of Pseudomonas aeruginosa Adaptation to a Novel Antimicrobial Substance

    PubMed Central

    Cierniak, Peter; Jübner, Martin; Müller, Stefan; Bender, Katja

    2013-01-01

    Antibiotic resistance has been reported since the introduction of synthetic antibiotics. Bacteria, such as one of the most common nosocomial pathogens P. aeruginosa, adapt quickly to changing environmental conditions, due to their short generation time. Thus microevolutional changes can be monitored in situ. In this study, the microevolutional process of Pseudomonas aeruginosa PAO1 resistance against a recently developed novel antibacterial zinc Schiff-base (ZSB) was investigated at the proteome level. After extended exposure to ZSB the passaged strain differed in tolerance against ZSB, with the adapted P. aeruginosa PAO1 exhibiting 1.6 times higher minimal inhibitory concentration. Using Two-dimensional Difference Gel Electrophoresis, the changes in the proteome of ZSB adapted P. aeruginosa PAO1 were examined by comparison with the non-adapted P. aeruginosa PAO1. The proteome of the adapted P. aeruginosa PAO1 strain differed significantly from the non-adapted in the abundance of two proteins when both strains were grown under stressing conditions. One protein could be identified as the outer membrane protein D that plays a role in uptake of basic amino acids as well as in carbapeneme resistance. The second protein has been identified as alkyl peroxide reductase subunit F. Our data indicated a slight increase in abundance of alkyl peroxide reductase F (AhpF) in the case of ZSB passaged P. aeruginosa PAO1. Higher abundance of Ahp has been discussed in the literature as a promoter of accelerated detoxification of benzene derivatives. The observed up-regulated AhpF thus appears to be connected to an increased tolerance against ZSB. Changes in the abundance of proteins connected to oxidative stress were also found after short-time exposure of P. aeruginosa PAO1 to the ZSB. Furthermore, adapted P. aeruginosa PAO1 showed increased tolerance against hydrogen peroxide and, in addition, showed accelerated degradation of ZSB, as determined by HPLC measurements. PMID:23869205

  3. Candida albicans Inhibits Pseudomonas aeruginosa Virulence through Suppression of Pyochelin and Pyoverdine Biosynthesis

    PubMed Central

    Lopez-Medina, Eduardo; Fan, Di; Coughlin, Laura A.; Ho, Evi X.; Lamont, Iain L.; Reimmann, Cornelia; Hooper, Lora V.; Koh, Andrew Y.

    2015-01-01

    Bacterial-fungal interactions have important physiologic and medical ramifications, but the mechanisms of these interactions are poorly understood. The gut is host to trillions of microorganisms, and bacterial-fungal interactions are likely to be important. Using a neutropenic mouse model of microbial gastrointestinal colonization and dissemination, we show that the fungus Candida albicans inhibits the virulence of the bacterium Pseudomonas aeruginosa by inhibiting P. aeruginosa pyochelin and pyoverdine gene expression, which plays a critical role in iron acquisition and virulence. Accordingly, deletion of both P. aeruginosa pyochelin and pyoverdine genes attenuates P. aeruginosa virulence. Heat-killed C. albicans has no effect on P. aeruginosa, whereas C. albicans secreted proteins directly suppress P. aeruginosa pyoverdine and pyochelin expression and inhibit P. aeruginosa virulence in mice. Interestingly, suppression or deletion of pyochelin and pyoverdine genes has no effect on P. aeruginosa’s ability to colonize the GI tract but does decrease P. aeruginosa’s cytotoxic effect on cultured colonocytes. Finally, oral iron supplementation restores P. aeruginosa virulence in P. aeruginosa and C. albicans colonized mice. Together, our findings provide insight into how a bacterial-fungal interaction can modulate bacterial virulence in the intestine. Previously described bacterial-fungal antagonistic interactions have focused on growth inhibition or colonization inhibition/modulation, yet here we describe a novel observation of fungal-inhibition of bacterial effectors critical for virulence but not important for colonization. These findings validate the use of a mammalian model system to explore the complexities of polymicrobial, polykingdom infections in order to identify new therapeutic targets for preventing microbial disease. PMID:26313907

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

    PubMed

    Amin, Muhammad T; Nawaz, Mohsin; Amin, Muhammad N; Han, Mooyoung

    2014-01-01

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

  5. CSA-131, a ceragenin active against colistin-resistant Acinetobacter baumannii and Pseudomonas aeruginosa clinical isolates.

    PubMed

    Vila-Farrés, Xavier; Callarisa, Anna Elena; Gu, Xiaobo; Savage, Paul B; Giralt, Ernest; Vila, Jordi

    2015-11-01

    In the last decade the number of Acinetobacter baumannii and Pseudomonas aeruginosa isolates showing extended drug resistance and pandrug resistance has steadily increased, thereby limiting or eliminating the antibiotics that can be used to treat infections by these micro-organisms. In addition, few antibiotics have been launched in the last decade. The objective of this study was to investigate the in vitro activity of several ceragenins against A. baumannii and P. aeruginosa. Four ceragenins (CSA-138, -13, -131 and -44) were tested both against colistin-susceptible and colistin-resistant A. baumannii and P. aeruginosa clinical isolates using the microdilution method. Time-kill curves of CSA-131 were performed against colistin-resistant A. baumannii and P. aeruginosa strains. The ceragenin CSA-131 showed the best activity against A. baumannii and P. aeruginosa, with minimum inhibitory concentrations (MICs) of 2 mg/L and <0.5 mg/L, respectively. MIC(50) and MIC(90) values were determined using 15 epidemiologically unrelated A. baumannii and P. aeruginosa strains, with MIC(50) and MIC(90) values for CSA-131 being 2 mg/L for A. baumannii and 1 mg/L and 2 mg/L, respectively, for P. aeruginosa. The killing curves of CSA-131 showed bactericidal behaviour at all of the concentrations tested, with re-growth at the lowest concentrations both in A. baumannii and P. aeruginosa. The good MICs of CSA-131 both against A. baumannii and P. aeruginosa and its high bactericidal activity may make this ceragenin a potential future agent to treat infections caused by these two pathogens even when the strain is resistant to colistin.

  6. Pseudomonas aeruginosa In Vitro Phenotypes Distinguish Cystic Fibrosis Infection Stages and Outcomes

    PubMed Central

    Rosenfeld, Margaret; Gibson, Ronald L.; Ramsey, Bonnie W.; Kulasekara, Hemantha D.; Retsch-Bogart, George Z.; Morgan, Wayne; Wolter, Daniel J.; Pope, Christopher E.; Houston, Laura S.; Kulasekara, Bridget R.; Khan, Umer; Burns, Jane L.; Miller, Samuel I.; Hoffman, Lucas R.

    2014-01-01

    Rationale: Pseudomonas aeruginosa undergoes phenotypic changes during cystic fibrosis (CF) lung infection. Although mucoidy is traditionally associated with transition to chronic infection, we hypothesized that additional in vitro phenotypes correlate with this transition and contribute to disease. Objectives: To characterize the relationships between in vitro P. aeruginosa phenotypes, infection stage, and clinical outcomes. Methods: A total of 649 children with CF and newly identified P. aeruginosa were followed for a median 5.4 years during which a total of 2,594 P. aeruginosa isolates were collected. Twenty-six in vitro bacterial phenotypes were assessed among the isolates, including measures of motility, exoproduct production, colony morphology, growth, and metabolism. Measurements and Main Results: P. aeruginosa phenotypes present at the time of culture were associated with both stage of infection (new onset, intermittent, or chronic) and the primary clinical outcome, occurrence of a pulmonary exacerbation (PE) in the subsequent 2 years. Two in vitro P. aeruginosa phenotypes best distinguished infection stages: pyoverdine production (31% of new-onset cultures, 48% of intermittent, 69% of chronic) and reduced protease production (31%, 39%, and 65%, respectively). The best P. aeruginosa phenotypic predictors of subsequent occurrence of a PE were mucoidy (odds ratio, 1.75; 95% confidence interval, 1.19–2.57) and reduced twitching motility (odds ratio, 1.43; 95% confidence interval, 1.11–1.84). Conclusions: In this large epidemiologic study of CF P. aeruginosa adaptation, P. aeruginosa isolates exhibited two in vitro phenotypes that best distinguished early and later infection stages. Among the many phenotypes tested, mucoidy and reduced twitching best predicted subsequent PE. These phenotypes indicate potentially useful prognostic markers of transition to chronic infection and advancing lung disease. PMID:24937177

  7. Microevolution of Pseudomonas aeruginosa to a chronic pathogen of the cystic fibrosis lung.

    PubMed

    Hogardt, Michael; Heesemann, Jürgen

    2013-01-01

    Pseudomonas aeruginosa is the leading pathogen of chronic cystic fibrosis (CF) lung infection. Life-long persistance of P. aeruginosa in the CF lung requires a sophisticated habitat-specific adaptation of this pathogen to the heterogeneous and fluctuating lung environment. Due to the high selective pressure of inflamed CF lungs, P. aeruginosa increasingly experiences complex physiological and morphological changes. Pulmonary adaptation of P. aeruginosa is mediated by genetic variations that are fixed by the repeating interplay of mutation and selection. In this context, the emergence of hypermutable phenotypes (mutator strains) obviously improves the microevolution of P. aeruginosa to the diverse microenvironments of the CF lung. Mutator phenotypes are amplified during CF lung disease and accelerate the intraclonal diversification of P. aeruginosa. The resulting generation of numerous subclonal variants is advantegous to prepare P. aeruginosa population for unpredictable stresses (insurance hypothesis) and thus supports long-term survival of this pathogen. Oxygen restriction within CF lung environment further promotes persistence of P. aeruginosa due to increased antibiotic tolerance, alginate production and biofilm formation. Finally, P. aeruginosa shifts from an acute virulent pathogen of early infection to a host-adapted chronic virulent pathogen of end-stage infection of the CF lung. Common changes that are observed among chronic P. aeruginosa CF isolates include alterations in surface antigens, loss of virulence-associated traits, increasing antibiotic resistances, the overproduction of the exopolysaccharide alginate and the modulation of intermediary and micro-aerobic metabolic pathways (Hogardt and Heesemann, Int J Med Microbiol 300(8):557-562, 2010). Loss-of-function mutations in mucA and lasR genes determine the transition to mucoidity and loss of quorum sensing, which are hallmarks of the chronic virulence potential of P. aeruginosa. Metabolic factors

  8. The purification, crystallization and preliminary structural characterization of PhzM, a phenazine-modifying methyltransferase from Pseudomonas aeruginosa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pyocyanin, phenazine-1-carboxylic acid and more than 70 related compounds collectively known as phenazines are produced by various species of Pseudomonas, including the fluorescent pseudomonad P. aeruginosa, a Gramnegative opportunistic pathogen in humans and animals. P. aeruginosa synthesizes a cha...

  9. In vitro antimicrobial resistance of Pseudomonas aeruginosa isolated from canine otitis externa in Rio de Janeiro, Brazil

    PubMed Central

    Penna, B.; Thomé, S.; Martins, R.; Martins, G.; Lilenbaum, W.

    2011-01-01

    Isolates of Pseudomonas aeruginosa (167) were obtained from 528 samples of canine otitis externa, identified by biochemical reactions and tested for susceptibility to 10 antimicrobials. The most effective drug was ciprofloxacin. The study reports alarming resistance among P. aeruginosa isolated from canine otitis externa samples in Rio de Janeiro, Brazil. PMID:24031774

  10. Chloronychia: green nail syndrome caused by Pseudomonas aeruginosa in elderly persons.

    PubMed

    Chiriac, Anca; Brzezinski, Piotr; Foia, Liliana; Marincu, Iosif

    2015-01-01

    Green nails, also known as chloronychia or green nail syndrome, are characterized by green discoloration of the nail plate (greenish-yellow, greenish-brown, greenish-black), proximal chronic non-tender paronychia, and distolateral onycholysis. The cause is Pseudomonas aeruginosa infection of the nail plate in persons whose hands are constantly exposed to water, soaps, and detergents or are subject to mechanical trauma, especially in the elderly. Green or black coloration of the nails should raise suspicion for Pseudomonas infection and be treated with an oral quinolone (ciprofloxacin), particularly in aged patients. We present three cases of green nails in elderly persons. PMID:25609938

  11. In Vivo Efficacy of Antimicrobials against Biofilm-Producing Pseudomonas aeruginosa

    PubMed Central

    Komor, Uliana; Kasnitz, Nadine; Bielecki, Piotr; Pils, Marina C.; Gocht, Benjamin; Moter, Annette; Rohde, Manfred; Weiss, Siegfried; Häussler, Susanne

    2015-01-01

    Patients suffering from cystic fibrosis (CF) are commonly affected by chronic Pseudomonas aeruginosa biofilm infections. This is the main cause for the high disease severity. In this study, we demonstrate that P. aeruginosa is able to efficiently colonize murine solid tumors after intravenous injection and to form biofilms in this tissue. Biofilm formation was evident by electron microscopy. Such structures could not be observed with transposon mutants, which were defective in biofilm formation. Comparative transcriptional profiling of P. aeruginosa indicated physiological similarity of the bacteria in the murine tumor model and the CF lung. The efficacy of currently available antibiotics for treatment of P. aeruginosa-infected CF lungs, such as ciprofloxacin, colistin, and tobramycin, could be tested in the tumor model. We found that clinically recommended doses of these antibiotics were unable to eliminate wild-type P. aeruginosa PA14 while being effective against biofilm-defective mutants. However, colistin-tobramycin combination therapy significantly reduced the number of P. aeruginosa PA14 cells in tumors at lower concentrations. Hence, we present a versatile experimental system that is providing a platform to test approved and newly developed antibiofilm compounds. PMID:26055372

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

    PubMed Central

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

    2016-01-01

    The increased reliance on colistin for treating multidrug-resistant Gram-negative bacterial infections has resulted in the emergence of colistin-resistant Pseudomonas aeruginosa. We attempted to identify genetic contributors to colistin resistance in vitro evolved isogenic colistin-resistant and -susceptible strains of two P. aeruginosa lineages (P5 and P155). Their evolutionary paths to acquisition and loss of colistin resistance were also tracked. Comparative genomic analysis revealed 13 and five colistin resistance determinants in the P5 and P155 lineages, respectively. Lipid A in colistin-resistant mutants was modified through the addition of 4-amino-L-arabinose; this modification was absent in colistin-susceptible revertant strains. Many amino acid substitutions that emerged during the acquisition of colistin resistance were reversed in colistin-susceptible revertants. We demonstrated that evolved colistin resistance in P. aeruginosa was mediated by a complicated regulatory network that likely emerges through diverse genetic alterations. Colistin-resistant P. aeruginosa became susceptible to the colistin upon its withdrawal because of genetic reversion. The mechanisms through which P. aeruginosa acquires and loses colistin resistance have implications on the treatment options that can be applied against P. aeruginosa infections, with respect to improving bactericidal efficacy and preventing further resistance to antibiotics. PMID:27150578

  13. Cyanide in bronchoalveolar lavage is not diagnostic for Pseudomonas aeruginosa in children with cystic fibrosis.

    PubMed

    Stutz, M D; Gangell, C L; Berry, L J; Garratt, L W; Sheil, B; Sly, P D

    2011-03-01

    Early detection of the cyanobacterium Pseudomonas aeruginosa in the lungs of young children with cystic fibrosis (CF) is considered the key to delaying chronic pulmonary disease. We investigated whether cyanide in bronchoalveolar lavage (BAL) fluid could be used as an early diagnostic biomarker of infection. Cyanide was measured in 226 BAL samples (36 P. aeruginosa infected) obtained from 96 infants and young children with CF participating in an early surveillance programme involving annual BAL. Cyanide was detected in 97.2% of P. aeruginosa infected and 60.5% of uninfected samples. Cyanide concentrations were significantly higher in BALs infected with P. aeruginosa (median (25th-75th percentile) 27.3 (22.1-33.3) μM) than those which were not (17.2 (7.85-23.0) μM, p<0.001). The best sensitivity, specificity, positive and negative predictive values were obtained with a cut-off concentration of 20.6 μM, and were 83%, 66%, 32% and 96%, respectively. Neutrophil number in BAL was a significant predictor of cyanide concentration (p<0.001). Cyanide concentration can distinguish between P. aeruginosa infected and uninfected BALs as a group, but not individually; therefore, cyanide is a poor diagnostic biomarker of P. aeruginosa infection. Cyanide levels in BAL are related to the level of neutrophilic inflammation.

  14. RNAi Screen Reveals an Abl Kinase-Dependent Host Cell Pathway Involved in Pseudomonas aeruginosa Internalization

    PubMed Central

    Pielage, Julia F.; Powell, Kimberly R.; Kalman, Daniel; Engel, Joanne N.

    2008-01-01

    Internalization of the pathogenic bacterium Pseudomonas aeruginosa by non-phagocytic cells is promoted by rearrangements of the actin cytoskeleton, but the host pathways usurped by this bacterium are not clearly understood. We used RNAi-mediated gene inactivation of ∼80 genes known to regulate the actin cytoskeleton in Drosophila S2 cells to identify host molecules essential for entry of P. aeruginosa. This work revealed Abl tyrosine kinase, the adaptor protein Crk, the small GTPases Rac1 and Cdc42, and p21-activated kinase as components of a host signaling pathway that leads to internalization of P. aeruginosa. Using a variety of complementary approaches, we validated the role of this pathway in mammalian cells. Remarkably, ExoS and ExoT, type III secreted toxins of P. aeruginosa, target this pathway by interfering with GTPase function and, in the case of ExoT, by abrogating P. aeruginosa–induced Abl-dependent Crk phosphorylation. Altogether, this work reveals that P. aeruginosa utilizes the Abl pathway for entering host cells and reveals unexpected complexity by which the P. aeruginosa type III secretion system modulates this internalization pathway. Our results furthermore demonstrate the applicability of using RNAi screens to identify host signaling cascades usurped by microbial pathogens that may be potential targets for novel therapies directed against treatment of antibiotic-resistant infections. PMID:18369477

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

    PubMed

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

    2016-02-01

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

  16. Pseudomonas aeruginosa in Swimming Pool Water: Evidences and Perspectives for a New Control Strategy

    PubMed Central

    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

  17. Effect of Tyrosol and Farnesol on Virulence and Antibiotic Resistance of Clinical Isolates of Pseudomonas aeruginosa

    PubMed Central

    Hassan Abdel-Rhman, Shaymaa; Mostafa El-Mahdy, Areej; El-Mowafy, Mohammed

    2015-01-01

    Mixed-species biofilms could create a protected environment that allows for survival to external antimicrobials and allows different bacterial-fungal interactions. Pseudomonas aeruginosa-Candida albicans coexistence is an example for such mixed-species community. Numerous reports demonstrated how P. aeruginosa or its metabolites could influence the growth, morphogenesis, and virulence of C. albicans. In this study, we investigated how the C. albicans quorum sensing compounds, tyrosol and farnesol, might affect Egyptian clinical isolates of P. aeruginosa regarding growth, antibiotic sensitivity, and virulence. We could demonstrate that tyrosol possesses an antibacterial activity against P. aeruginosa (10 µM inhibited more than 50% of growth after 16 h cultivation). Moreover, we could show for the first time that tyrosol strongly inhibits the production of the virulence factors hemolysin and protease in P. aeruginosa, whereas farnesol inhibits, to lower extent, hemolysin production in this bacterial pathogen. Cumulatively, tyrosol is expected to strongly affect P. aeruginosa in mixed microbial biofilm. PMID:26844228

  18. Inhibition of Pseudomonas aeruginosa Swarming Motility by 1-Naphthol and Other Bicyclic Compounds Bearing Hydroxyl Groups

    PubMed Central

    Oura, Hiromu; Tashiro, Yosuke; Toyofuku, Masanori; Ueda, Kousetsu; Kiyokawa, Tatsunori; Ito, Satoshi; Takahashi, Yurika; Lee, Seunguk; Nojiri, Hideaki; Nakajima-Kambe, Toshiaki; Uchiyama, Hiroo; Futamata, Hiroyuki

    2015-01-01

    Many bacteria convert bicyclic compounds, such as indole and naphthalene, to oxidized compounds, including hydroxyindoles and naphthols. Pseudomonas aeruginosa, a ubiquitous bacterium that inhabits diverse environments, shows pathogenicity against animals, plants, and other microorganisms, and increasing evidence has shown that several bicyclic compounds alter the virulence-related phenotypes of P. aeruginosa. Here, we revealed that hydroxyindoles (4- and 5-hydroxyindoles) and naphthalene derivatives bearing hydroxyl groups specifically inhibit swarming motility but have minor effects on other motilities, including swimming and twitching, in P. aeruginosa. Further analyses using 1-naphthol showed that this effect is also associated with clinically isolated hyperswarming P. aeruginosa cells. Swarming motility is associated with the dispersion of cells from biofilms, and the addition of 1-naphthol maintained biofilm biomass without cell dispersion. We showed that this 1-naphthol-dependent swarming inhibition is independent of changes of rhamnolipid production and the intracellular level of signaling molecule cyclic-di-GMP (c-di-GMP). Transcriptome analyses revealed that 1-naphthol increases gene expression associated with multidrug efflux and represses gene expression associated with aerotaxis and with pyochelin, flagellar, and pilus synthesis. In the present study, we showed that several bicyclic compounds bearing hydroxyl groups inhibit the swarming motility of P. aeruginosa, and these results provide new insight into the chemical structures that inhibit the specific phenotypes of P. aeruginosa. PMID:25681177

  19. Pseudomonas aeruginosa Activates PKC-Alpha to Invade Middle Ear Epithelial Cells

    PubMed Central

    Mittal, Rahul; Grati, M’hamed; Yan, Denise; Liu, Xue Z.

    2016-01-01

    Otitis media (OM) is a group of complex inflammatory disorders affecting the middle ear which can be acute or chronic. Chronic suppurative otitis media (CSOM) is a form of chronic OM characterized by tympanic membrane perforation and discharge. Despite the significant impact of CSOM on human population, it is still an understudied and unexplored research area. CSOM is a leading cause of hearing loss and life-threatening central nervous system complications. Bacterial exposure especially Pseudomonas aeruginosa is the most common cause of CSOM. Our previous studies have demonstrated that P. aeruginosa invades human middle ear epithelial cells (HMEECs). However, molecular mechanisms leading to bacterial invasion of HMEECs are not known. The aim of this study is to characterize the role of PKC pathway in the ability of P. aeruginosa to colonize HMEECs. We observed that otopathogenic P. aeruginosa activates the PKC pathway, specifically phosphorylation of PKC-alpha (PKC-α) in HMEECs. The ability of otopathogenic P. aeruginosa to phosphorylate PKC-α depends on bacterial OprF expression. The activation of PKC-α was associated with actin condensation. Blocking the PKC pathway attenuated the ability of bacteria to invade HMEECs and subsequent actin condensation. This study, for the first time, demonstrates that the host PKC-α pathway is involved in invasion of HMEECs by P. aeruginosa and subsequently to cause OM. Characterizing the role of the host signaling pathway in the pathogenesis of CSOM will provide novel avenues to design effective treatment modalities against the disease. PMID:26973629

  20. Pseudomonas aeruginosa Uses Multiple Pathways To Acquire Iron during Chronic Infection in Cystic Fibrosis Lungs

    PubMed Central

    Konings, Anna F.; Martin, Lois W.; Sharples, Katrina J.; Roddam, Louise F.; Latham, Roger; Reid, David W.

    2013-01-01

    Pseudomonas aeruginosa chronically infects the lungs of more than 80% of adult patients with cystic fibrosis (CF) and is a major contributor to the progression of disease pathology. P. aeruginosa requires iron for growth and has multiple iron uptake systems that have been studied in bacteria grown in laboratory culture. The purpose of this research was to determine which of these are active during infection in CF. RNA was extracted from 149 sputum samples obtained from 23 CF patients. Reverse transcription–quantitative real-time PCR (RT-qPCR) was used to measure the expression of P. aeruginosa genes encoding transport systems for the siderophores pyoverdine and pyochelin, for heme, and for ferrous ions. Expression of P. aeruginosa genes could be quantified in 89% of the sputum samples. Expression of genes associated with siderophore-mediated iron uptake was detected in most samples but was at low levels in some samples, indicating that other iron uptake mechanisms are active. Expression of genes encoding heme transport systems was also detected in most samples, indicating that heme uptake occurs during infection in CF. feoB expression was detected in all sputum samples, implying an important role for ferrous ion uptake by P. aeruginosa in CF. Our data show that multiple P. aeruginosa iron uptake mechanisms are active in chronic CF infection and that RT-qPCR of RNA extracted from sputum provides a powerful tool for investigating bacterial physiology during infection in CF. PMID:23690396

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

    PubMed Central

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

    2016-01-01

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

  2. Pseudomonas aeruginosa in Swimming Pool Water: Evidences and Perspectives for a New Control Strategy.

    PubMed

    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

  3. Carbapenem resistance in Pseudomonas aeruginosa and Acinetobacter baumannii in the nosocomial setting in Latin America.

    PubMed

    Labarca, Jaime A; Salles, Mauro José Costa; Seas, Carlos; Guzmán-Blanco, Manuel

    2016-01-01

    Increasing prevalence of carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii strains in the nosocomial setting in Latin America represents an emerging challenge to public health, as the range of therapeutic agents active against these pathogens becomes increasingly constrained. We review published reports from 2002 to 2013, compiling data from throughout the region on prevalence, mechanisms of resistance and molecular epidemiology of carbapenem-resistant strains of P. aeruginosa and A. baumannii. We find rates of carbapenem resistance up to 66% for P. aeruginosa and as high as 90% for A. baumannii isolates across the different countries of Latin America, with the resistance rate of A. baumannii isolates greater than 50% in many countries. An outbreak of the SPM-1 carbapenemase is a chief cause of resistance in P. aeruginosa strains in Brazil. Elsewhere in Latin America, members of the VIM family are the most important carbapenemases among P. aeruginosa strains. Carbapenem resistance in A. baumannii in Latin America is predominantly due to the oxacillinases OXA-23, OXA-58 and (in Brazil) OXA-143. Susceptibility of P. aeruginosa and A. baumannii to colistin remains high, however, development of resistance has already been detected in some countries. Better epidemiological data are needed to design effective infection control interventions.

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

    PubMed

    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.

  5. Pseudomonas aeruginosa uses multiple pathways to acquire iron during chronic infection in cystic fibrosis lungs.

    PubMed

    Konings, Anna F; Martin, Lois W; Sharples, Katrina J; Roddam, Louise F; Latham, Roger; Reid, David W; Lamont, Iain L

    2013-08-01

    Pseudomonas aeruginosa chronically infects the lungs of more than 80% of adult patients with cystic fibrosis (CF) and is a major contributor to the progression of disease pathology. P. aeruginosa requires iron for growth and has multiple iron uptake systems that have been studied in bacteria grown in laboratory culture. The purpose of this research was to determine which of these are active during infection in CF. RNA was extracted from 149 sputum samples obtained from 23 CF patients. Reverse transcription-quantitative real-time PCR (RT-qPCR) was used to measure the expression of P. aeruginosa genes encoding transport systems for the siderophores pyoverdine and pyochelin, for heme, and for ferrous ions. Expression of P. aeruginosa genes could be quantified in 89% of the sputum samples. Expression of genes associated with siderophore-mediated iron uptake was detected in most samples but was at low levels in some samples, indicating that other iron uptake mechanisms are active. Expression of genes encoding heme transport systems was also detected in most samples, indicating that heme uptake occurs during infection in CF. feoB expression was detected in all sputum samples, implying an important role for ferrous ion uptake by P. aeruginosa in CF. Our data show that multiple P. aeruginosa iron uptake mechanisms are active in chronic CF infection and that RT-qPCR of RNA extracted from sputum provides a powerful tool for investigating bacterial physiology during infection in CF. PMID:23690396

  6. Inhibition of Pseudomonas aeruginosa swarming motility by 1-naphthol and other bicyclic compounds bearing hydroxyl groups.

    PubMed

    Oura, Hiromu; Tashiro, Yosuke; Toyofuku, Masanori; Ueda, Kousetsu; Kiyokawa, Tatsunori; Ito, Satoshi; Takahashi, Yurika; Lee, Seunguk; Nojiri, Hideaki; Nakajima-Kambe, Toshiaki; Uchiyama, Hiroo; Futamata, Hiroyuki; Nomura, Nobuhiko

    2015-04-01

    Many bacteria convert bicyclic compounds, such as indole and naphthalene, to oxidized compounds, including hydroxyindoles and naphthols. Pseudomonas aeruginosa, a ubiquitous bacterium that inhabits diverse environments, shows pathogenicity against animals, plants, and other microorganisms, and increasing evidence has shown that several bicyclic compounds alter the virulence-related phenotypes of P. aeruginosa. Here, we revealed that hydroxyindoles (4- and 5-hydroxyindoles) and naphthalene derivatives bearing hydroxyl groups specifically inhibit swarming motility but have minor effects on other motilities, including swimming and twitching, in P. aeruginosa. Further analyses using 1-naphthol showed that this effect is also associated with clinically isolated hyperswarming P. aeruginosa cells. Swarming motility is associated with the dispersion of cells from biofilms, and the addition of 1-naphthol maintained biofilm biomass without cell dispersion. We showed that this 1-naphthol-dependent swarming inhibition is independent of changes of rhamnolipid production and the intracellular level of signaling molecule cyclic-di-GMP (c-di-GMP). Transcriptome analyses revealed that 1-naphthol increases gene expression associated with multidrug efflux and represses gene expression associated with aerotaxis and with pyochelin, flagellar, and pilus synthesis. In the present study, we showed that several bicyclic compounds bearing hydroxyl groups inhibit the swarming motility of P. aeruginosa, and these results provide new insight into the chemical structures that inhibit the specific phenotypes of P. aeruginosa. PMID:25681177

  7. Pseudomonas aeruginosa quorum sensing molecules correlate with clinical status in cystic fibrosis.

    PubMed

    Barr, Helen L; Halliday, Nigel; Cámara, Miguel; Barrett, David A; Williams, Paul; Forrester, Douglas L; Simms, Rebecca; Smyth, Alan R; Honeybourne, David; Whitehouse, Joanna L; Nash, Edward F; Dewar, Jane; Clayton, Andrew; Knox, Alan J; Fogarty, Andrew W

    2015-10-01

    Pseudomonas aeruginosa produces quorum sensing signal molecules that are potential biomarkers for infection.A prospective study of 60 cystic fibrosis patients with chronic P. aeruginosa, who required intravenous antibiotics for pulmonary exacerbations, was undertaken. Clinical measurements and biological samples were obtained at the start and end of the treatment period. Additional data were available for 29 of these patients when they were clinically stable.Cross-sectionally, quorum sensing signal molecules were detectable in the sputum, plasma and urine of 86%, 75% and 83% patients, respectively. They were positively correlated between the three biofluids. Positive correlations were observed for most quorum sensing signal molecules in sputum, plasma and urine, with quantitative measures of pulmonary P. aeruginosa load at the start of a pulmonary exacerbation. Plasma concentrations of 2-nonyl-4-hydroxy-quinoline (NHQ) were significantly higher at the start of a pulmonary exacerbation compared to clinical stability (p<0.01). Following the administration of systemic antibiotics, plasma 2-heptyl-4-hydroxyquinoline (p=0.02) and NHQ concentrations (p<0.01) decreased significantly.In conclusion, quorum sensing signal molecules are detectable in cystic fibrosis patients with pulmonary P. aeruginosa infection and are positively correlated with quantitative measures of P. aeruginosa. NHQ correlates with clinical status and has potential as a novel biomarker for P. aeruginosa infection.

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

    PubMed Central

    van Belkum, Alex; Soriaga, Leah B.; LaFave, Matthew C.; Akella, Srividya; Veyrieras, Jean-Baptiste; Barbu, E. Magda; Shortridge, Dee; Blanc, Bernadette; Hannum, Gregory; Zambardi, Gilles; Miller, Kristofer; Enright, Mark C.; Mugnier, Nathalie; Brami, Daniel; Schicklin, Stéphane; Felderman, Martina; Schwartz, Ariel S.; Richardson, Toby H.; Peterson, Todd C.; Hubby, Bolyn

    2015-01-01

    ABSTRACT Pseudomonas aeruginosa is an antibiotic-refractory pathogen with a large genome and extensive genotypic diversity. Historically, P. aeruginosa has been a major model system for understanding the molecular mechanisms underlying type I clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated protein (CRISPR-Cas)-based bacterial immune system function. However, little information on the phylogenetic distribution and potential role of these CRISPR-Cas systems in molding the P. aeruginosa accessory genome and antibiotic resistance elements is known. Computational approaches were used to identify and characterize CRISPR-Cas systems within 672 genomes, and in the process, we identified a previously unreported and putatively mobile type I-C P. aeruginosa CRISPR-Cas system. Furthermore, genomes harboring noninhibited type I-F and I-E CRISPR-Cas systems were on average ~300 kb smaller than those without a CRISPR-Cas system. In silico analysis demonstrated that the accessory genome (n = 22,036 genes) harbored the majority of identified CRISPR-Cas targets. We also assembled a global spacer library that aided the identification of difficult-to-characterize mobile genetic elements within next-generation sequencing (NGS) data and allowed CRISPR typing of a majority of P. aeruginosa strains. In summary, our analysis demonstrated that CRISPR-Cas systems play an important role in shaping the accessory genomes of globally distributed P. aeruginosa isolates. PMID:26604259

  9. Complete Genome Sequence of Pseudomonas aeruginosa Phage AAT-1

    PubMed Central

    Andrade-Domínguez, Andrés

    2016-01-01

    Aspects of the interaction between phages and animals are of interest and importance for medical applications. Here, we report the genome sequence of the lytic Pseudomonas phage AAT-1, isolated from mammalian serum. AAT-1 is a double-stranded DNA phage, with a genome of 57,599 bp, containing 76 predicted open reading frames. PMID:27563032

  10. Complete Genome Sequence of Pseudomonas aeruginosa Phage AAT-1.

    PubMed

    Andrade-Domínguez, Andrés; Kolter, Roberto

    2016-01-01

    Aspects of the interaction between phages and animals are of interest and importance for medical applications. Here, we report the genome sequence of the lytic Pseudomonas phage AAT-1, isolated from mammalian serum. AAT-1 is a double-stranded DNA phage, with a genome of 57,599 bp, containing 76 predicted open reading frames. PMID:27563032

  11. Characterization of a new Pseudomonas aeruginosa strain NJ-15 as a potential biocontrol agent.

    PubMed

    Bano, Nazneen; Musarrat, Javed

    2003-05-01

    Phylogenetic characterization of soil isolate NJ-15, based on sequence homology of a partial 746-bp fragment of 16SrDNA amplicon, with the ribosomal database sequences (http://www.msu.edu/RDP/cgis/phylip.cgi), validated the strain as Pseudomonas aeruginosa. The strain NJ-15 produced a substantial amount of indole acetic acid (IAA) in tryptophan-supplemented medium. Besides, the strain also exhibited significant production of both the siderophore and hydrogen cyanide (HCN) on chrome azurol S and King's B media, respectively. The data revealed lower HCN production under iron-limiting conditions vis-à-vis higher HCN release with iron stimulation. Significant growth inhibition of phytopathogenic fungi occurred in the order as Fusarium oxysporum > Trichoderma herizum > Alternaria alternata > Macrophomina phasiolina upon incubation with strain NJ-15 cells. Thus, the secondary metabolites producing new Pseudomonas aeruginosa strain NJ-15 exhibited innate potential of plant growth promotion and biocontrol activities in vitro.

  12. Biodegradation of Decabromodiphenyl Ether (BDE-209) by Crude Enzyme Extract from Pseudomonas aeruginosa

    PubMed Central

    Liu, Yu; Gong, Ai-Jun; Qiu, Li-Na; Li, Jing-Rui; Li, Fu-Kai

    2015-01-01

    The biodegradation effect and mechanism of decabromodiphenyl ether (BDE-209) by crude enzyme extract from Pseudomonas aeruginosa were investigated. The results demonstrated that crude enzyme extract exhibited obviously higher degradation efficiency and shorter biodegradation time than Pseudomonas aeruginosa itself. Under the optimum conditions of pH 9.0, 35 °C and protein content of 2000 mg/L, 92.77% of the initial BDE-209 (20 mg/L) was degraded after 5 h. A BDE-209 biodegradation pathway was proposed on the basis of the biodegradation products identified by GC-MS analysis. The biodegradation mechanism showed that crude enzyme extract degraded BDE-209 into lower brominated PBDEs and OH-PBDEs through debromination and hydroxylation of the aromatic rings. PMID:26393637

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

    PubMed Central

    Smalley, Nicole E.; An, Dingding; Parsek, Matthew R.

    2015-01-01

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

  14. Emergence of nylon oligomer degradation enzymes in Pseudomonas aeruginosa PAO through experimental evolution.

    PubMed Central

    Prijambada, I D; Negoro, S; Yomo, T; Urabe, I

    1995-01-01

    Through selective cultivation with 6-aminohexanoate linear dimer, a by-product of nylon-6 manufacture, as the sole source of carbon and nitrogen, Pseudomonas aeruginosa PAO, which initially has no enzyme activity to degrade this xenobiotic compound, was successfully expanded in its metabolic ability. Two new enzyme activities, 6-aminohexanoate cyclic dimer hydrolase and 6-aminohexanoate dimer hydrolase, were detected in the adapted strains. PMID:7646041

  15. Increased concentration of Pseudomonas aeruginosa and Staphylococcus sp. in small animals exposed to aerospace environments

    NASA Technical Reports Server (NTRS)

    Guthrie, R. K.

    1976-01-01

    The effects of increased concentrations of PSEUDOMONAS AERUGINOSA AND STAPHYLOCOCCUS in the total bacterial flora of small animals exposed to simulated spacecraft environments were evaluated. Tests to detect changes in infectivity, effects of antibiotic treatments, immune responses to bacterial antigens, and effectiveness of immune responses in the experimental environment were conducted. The most significant results appear to be the differences in immune responses at simulated altitudes and the production of infection in the presence of a specific antibody.

  16. Pseudomonas aeruginosa septic trapezo-metacarpal arthritis after prostate laser vaporization.

    PubMed

    Lepetit, C; Le Gal, S; Michon, J; Collon, S; Tillou, X

    2015-08-01

    Prostatic laser vaporization resection is a new and fast growing technique. Most publications compare this technique to the standard diathermic snare prostate resection without considering its particular complications. Septic arthritis of the trapezio-metacarpal joint is particularly rare if it has a haematogenous origin. We present here the case of a 65-year-old man with an isolated trapezio-metacarpal Pseudomonas aeruginosa arthritis with a haematogenous origin following a laser vaporization prostate resection.

  17. Diverse Mobilized Class 1 Integrons Are Common in the Chromosomes of Pathogenic Pseudomonas aeruginosa Clinical Isolates

    PubMed Central

    Martinez, Elena; Marquez, Carolina; Ingold, Ana; Merlino, John; Djordjevic, Steven P.; Roy Chowdhury, Piklu

    2012-01-01

    Eleven clinical class 1 integron-containing Pseudomonas aeruginosa isolates from Australia and Uruguay were investigated for the genomic locations of these elements. Several novel class 1 integrons/transposons were found in at least four distinct locations in the chromosome, including genomic islands. These elements seem to be undergoing successful dispersal by lateral gene transfer since integrons were identified across several lineages and more than one clonal line. PMID:22271862

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

    PubMed

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

    2013-12-01

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

  19. Mucoid conversion by phages of Pseudomonas aeruginosa strains from patients with cystic fibrosis.

    PubMed Central

    Miller, R V; Rubero, V J

    1984-01-01

    A total of 21 of 22 independent isolates of cystic fibrosis-associated Pseudomonas aeruginosa were found to be lysogenic for DNA-containing, complex capsid viruses. Several of the phages demonstrated the ability to select mucoid cells from populations of nonmucoid bacteria. Conversion to mucoid growth was more frequently achieved when phages were isolated from mucoid as opposed to nonmucoid cystic fibrosis-associated strains. PMID:6429192

  20. Tn5 insertion mutants of Pseudomonas aeruginosa deficient in surface expression of ferripyochelin-binding protein

    SciTech Connect

    Sokol, P.A.

    1987-07-01

    Transposon (Tn5) insertion mutants were isolated in Pseudomonas aeruginosa PAO. These mutants were screened for expression of the ferripyochelin-binding protein with monoclonal antibody in a whole-cell immunoblot assay. Fourteen mutants were identified which did not express ferripyochelin-binding protein on the cell surface. These mutants did not take up /sup 59/Fe-labeled pyochelin and grew slowly in the presence of iron chelators.

  1. Community Acquired Chronic Arthritis due to Pseudomonas aeruginosa in a Previously Healthy Pregnant Woman

    PubMed Central

    Yilmaz, Mesut; Arslan, Ferhat; Mert, Ali

    2014-01-01

    Septic arthritis caused by Pseudomonas aeruginosa is uncommon in the immunocompetent population, despite its occurrence in younger patients with open injuries and in intravenous drug abusers. Here we report a case of septic arthritis caused by P. aeruginosa. This case is unique for several reasons. First, it is a case of septic arthritis in a pregnant woman with no traditional risk factors reported in the literature including history of prior traumatic events, hospitalisation, or chronic underlying disease. She was suspected of having transient osteoporosis associated with pregnancy to involve both hip joints. Second, this is the first reported case of a community acquired chronic septic arthritis due to P. aeruginosa involving large joints of both upper and lower extremities. The patient was treated successfully with a combination of ceftazidime and amikacin for 4 weeks followed by oral ciprofloxacin 750 mg twice daily for 8 weeks. PMID:25371836

  2. Pseudomonas aeruginosa anaerobic respiration in biofilms: relationships to cystic fibrosis pathogenesis.

    PubMed

    Yoon, Sang Sun; Hennigan, Robert F; Hilliard, George M; Ochsner, Urs A; Parvatiyar, Kislay; Kamani, Moneesha C; Allen, Holly L; DeKievit, Teresa R; Gardner, Paul R; Schwab, Ute; Rowe, John J; Iglewski, Barbara H; McDermott, Timothy R; Mason, Ronald P; Wozniak, Daniel J; Hancock, Robert E W; Parsek, Matthew R; Noah, Terry L; Boucher, Richard C; Hassett, Daniel J

    2002-10-01

    Recent data indicate that cystic fibrosis (CF) airway mucus is anaerobic. This suggests that Pseudomonas aeruginosa infection in CF reflects biofilm formation and persistence in an anaerobic environment. P. aeruginosa formed robust anaerobic biofilms, the viability of which requires rhl quorum sensing and nitric oxide (NO) reductase to modulate or prevent accumulation of toxic NO, a byproduct of anaerobic respiration. Proteomic analyses identified an outer membrane protein, OprF, that was upregulated approximately 40-fold under anaerobic versus aerobic conditions. Further, OprF exists in CF mucus, and CF patients raise antisera to OprF. An oprF mutant formed poor anaerobic biofilms, due, in part, to defects in anaerobic respiration. Thus, future investigations of CF pathogenesis and therapy should include a better understanding of anaerobic metabolism and biofilm development by P. aeruginosa.

  3. Microbial pathogenesis in cystic fibrosis: mucoid Pseudomonas aeruginosa and Burkholderia cepacia.

    PubMed Central

    Govan, J R; Deretic, V

    1996-01-01

    Respiratory infections with Pseudomonas aeruginosa and Burkholderia cepacia play a major role in the pathogenesis of cystic fibrosis (CF). This review summarizes the latest advances in understanding host-pathogen interactions in CF with an emphasis on the role and control of conversion to mucoidy in P. aeruginosa, a phenomenon epitomizing the adaptation of this opportunistic pathogen to the chronic chourse of infection in CF, and on the innate resistance to antibiotics of B. cepacia, person-to-person spread, and sometimes rapidly fatal disease caused by this organism. While understanding the mechanism of conversion to mucoidy in P. aeruginosa has progressed to the point where this phenomenon has evolved into a model system for studying bacterial stress response in microbial pathogenesis, the more recent challenge with B. cepacia, which has emerged as a potent bona fide CF pathogen, is discussed in the context of clinical issues, taxonomy, transmission, and potential modes of pathogenicity. PMID:8840786

  4. The roles of biofilm matrix polysaccharide Psl in mucoid Pseudomonas aeruginosa biofilms.

    PubMed

    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.

  5. Production of biosurfactant by Pseudomonas aeruginosa grown on cashew apple juice.

    PubMed

    Rocha, Maria V P; Souza, Maria C M; Benedicto, Sofia C L; Bezerra, Márcio S; Macedo, Gorete R; Pinto, Gustavo A Saavedra; Gonçalves, Luciana R B

    2007-04-01

    In this work, the ability of biosurfactant production by Pseudomonas aeruginosa in batch cultivation using cashew apple juice (CAJ) and mineral media was evaluated. P. aeruginosa was cultivated in CAJ, which was supplemented with peptone (5.0 g/L) and nutritive broth. All fermentation assays were performed in Erlenmeyer flasks containing 300 mL, incubated at 30 degrees C and 150 rpm. Cell growth (biomass and cell density), pH, and superficial tension were monitored vs time. Surface tension was reduced by 10.58 and 41% when P. aeruginosa was cultivated in nutrient broth and CAJ supplemented with peptone, respectively. These results indicated that CAJ is an adequate medium for growth and biosurfactant production. Best results of biosurfactant production were obtained when CAJ was supplemented with peptone.

  6. Pseudomonas aeruginosa: targeting cell-wall metabolism for new antibacterial discovery and development.

    PubMed

    Lamers, Ryan P; Burrows, Lori L

    2016-06-01

    Pseudomonas aeruginosa is a leading cause of hospital-acquired infections and is resistant to most antibiotics. With therapeutic options against P. aeruginosa dwindling, and the lack of new antibiotics in advanced developmental stages, strategies for preserving the effectiveness of current antibiotics are urgently required. β-Lactam antibiotics are important agents for treating P. aeruginosa infections, thus, adjuvants that potentiate the activity of these compounds are desirable for extending their lifespan while new antibiotics - or antibiotic classes - are discovered and developed. In this review, we discuss recent research that has identified exploitable targets of cell-wall metabolism for the design and development of compounds that hinder resistance and potentiate the activity of antipseudomonal β-lactams. PMID:27228070

  7. Host defense against Pseudomonas aeruginosa requires ceramide-rich membrane rafts.

    PubMed

    Grassmé, H; Jendrossek, V; Riehle, A; von Kürthy, G; Berger, J; Schwarz, H; Weller, M; Kolesnick, R; Gulbins, E

    2003-03-01

    Pseudomonas aeruginosa infection is a serious complication in patients with cystic fibrosis and in immunocompromised individuals. Here we show that P. aeruginosa infection triggers activation of the acid sphingomyelinase and the release of ceramide in sphingolipid-rich rafts. Ceramide reorganizes these rafts into larger signaling platforms that are required to internalize P. aeruginosa, induce apoptosis and regulate the cytokine response in infected cells. Failure to generate ceramide-enriched membrane platforms in infected cells results in an unabated inflammatory response, massive release of interleukin (IL)-1 and septic death of mice. Our findings show that ceramide-enriched membrane platforms are central to the host defense against this potentially lethal pathogen. PMID:12563314

  8. First Detection of Metallo-β-Lactamase VIM-2 in Pseudomonas aeruginosa Isolates from Colombia

    PubMed Central

    Villegas, Maria Virginia; Lolans, Karen; del Rosario Olivera, Maria; Suarez, Carlos José; Correa, Adriana; Queenan, Anne Marie; Quinn, John P.

    2006-01-01

    Carbapenem resistance rates in Pseudomonas aeruginosa isolates in Colombia, as in many South American countries, are high for reasons that remain unclear. From our nationwide network, we describe the first detection of the metallo-β-lactamase VIM-2 in clinical isolates of P. aeruginosa from multiple cities within Colombia. Metallo-β-lactamases were not detected in the two centers with the highest imipenem resistance rates. Clonality was noted in five of the eight centers with strains meeting the criteria for molecular typing. The high carbapenem resistance in P. aeruginosa in Colombia may be attributable to a combination of factors, including the presence of metallo-β-lactamases and nosocomial transmission. PMID:16377690

  9. Volatile Compounds Emitted by Pseudomonas aeruginosa Stimulate Growth of the Fungal Pathogen Aspergillus fumigatus

    PubMed Central

    Briard, Benoit; Heddergott, Christoph

    2016-01-01

    ABSTRACT Chronic lung infections with opportunistic bacterial and fungal pathogens are a major cause of morbidity and mortality especially in patients with cystic fibrosis. Pseudomonas aeruginosa is the most frequently colonizing bacterium in these patients, and it is often found in association with the filamentous fungus Aspergillus fumigatus. P. aeruginosa is known to inhibit the growth of A. fumigatus in situations of direct contact, suggesting the existence of interspecies communication that may influence disease outcome. Our study shows that the lung pathogens P. aeruginosa and A. fumigatus can interact at a distance via volatile-mediated communication and expands our understanding of interspecific signaling in microbial communities. PMID:26980832

  10. Antimicrobial testing of selected fluoroquinolones against Pseudomonas aeruginosa isolated from canine otitis.

    PubMed

    McKay, Lindsay; Rose, Crystal D Schuman; Matousek, Jennifer L; Schmeitzel, Lynn S; Gibson, Nicole M; Gaskin, Jack M

    2007-01-01

    A total of 100 Pseudomonas aeruginosa (P. aeruginosa) isolates were collected over a 1.5-year period from cases of canine otitis. Sensitivities to enrofloxacin, marbofloxacin, and orbifloxacin were determined using minimum inhibitory concentration testing (MICT). Isolates were also tested for sensitivities to enrofloxacin and marbofloxacin using disk-diffusion susceptibility testing (DDST). Isolates were significantly more sensitive to marbofloxacin than to enrofloxacin (z = -4.57; P<0.05) or orbifloxacin (z = -5.02; P<0.05). Agreement was 87% between MICT and DDST for marbofloxacin, with approximately equal numbers of overestimation and underestimation errors. Agreement was 74% between MICT and DDST for enrofloxacin, but DDST tended to overestimate the number of enrofloxacin-susceptible strains. These results suggest that marbofloxacin is more effective against P. aeruginosa than either enrofloxacin or orbifloxacin and that relying on DDST may lead to ineffective enrofloxacin treatment.

  11. Bacteriophage can lyse antibiotic-resistant Pseudomonas aeruginosa isolated from canine diseases

    PubMed Central

    FURUSAWA, Takaaki; IWANO, Hidetomo; HIGUCHI, Hidetoshi; YOKOTA, Hiroshi; USUI, Masaru; IWASAKI, Tomohito; TAMURA, Yutaka

    2016-01-01

    Pseudomonas aeruginosa is a pathogen frequently identified as the cause of diverse infections or chronic disease. This microbe has natural resistance to several kinds of antibiotics, because of the species’ outer membrane, efflux pumps and growth as a biofilm. This bacterium can acquire increased resistance with specific point mutations. Bacteriophage (phage), however, can lyse these bacteria. Therefore, in the present study, we assessed the host range of phages isolates and their ability to lyse antibiotic-resistant P. aeruginosa. Present phages could lyse many strains of P. aeruginosa (28/39), including strains with high resistance to fluoroquinolones (4/6). In conclusion, application of phages for antibiotic-resistant bacteria is greatly effective. To avoid pervasive antibiotic-resistant bacteria, further development of phage usage for disease treatment is required. PMID:26876365

  12. Production of Biosurfactant by Pseudomonas aeruginosa Grown on Cashew Apple Juice

    NASA Astrophysics Data System (ADS)

    Rocha, Maria V. P.; Souza, Maria C. M.; Benedicto, Sofia C. L.; Bezerra, Márcio S.; Macedo, Gorete R.; Saavedra Pinto, Gustavo A.; Gonçalves, Luciana R. B.

    In this work, the ability of biosurfactant production by Pseudomonas aeruginosa in batch cultivation using cashew apple juice (CAJ) and mineral media was evaluated. P. aeruginosa was cultivated in CAJ, which was supplemented with peptone (5.0 g/L) and nutritive broth. All fermentation assays were performed in Erlenmeyer flasks containing 300 mL, incubated at 30°C and 150 rpm. Cell growth (biomass and cell density), pH, and superficial tension were monitored vs time. Surface tension was reduced by 10.58 and 41% when P. aeruginosa was cultivated in nutrient broth and CAJ supplemented with peptone, respectively. These results indicated that CAJ is an adequate medium for growth and biosurfactant production. Best results of biosurfactant production were obtained when CAJ was supplemented with peptone.

  13. Synergistic action of starch and honey against Pseudomonas aeruginosa in correlation with diastase number.

    PubMed

    Boukraa, Laïd; Benbarek, Hama; Aissat, Saâd

    2008-03-01

    To evaluate the synergistic action of starch on the antibacterial activity of honey against Pseudomonas aeruginosa, a comparative method of adding honey with and without starch to culture media was used. P. aeruginosa (ATCC 27853) was used to determine the minimum inhibitory concentration (MIC) of five varieties of honey. In a second step, lower concentrations of honey than the MIC were incubated with a set of concentrations of starch and then added to media to determine the minimum synergistic inhibitory concentration. The MIC for the five varieties of honey without starch against P. aeruginosa ranged between 15% and 26% (vol/vol). When starch was incubated with honey and then added to media, a significant MIC drop has been noticed with each variety and it ranged between 30.7% and 46.6%. No significant correlation has been established between the MIC drop and the diastase number. PMID:18315514

  14. Phage Therapy: a Step Forward in the Treatment of Pseudomonas aeruginosa Infections.

    PubMed

    Pires, Diana P; Vilas Boas, Diana; Sillankorva, Sanna; Azeredo, Joana

    2015-08-01

    Antimicrobial resistance constitutes one of the major worldwide public health concerns. Bacteria are becoming resistant to the vast majority of antibiotics, and nowadays, a common infection can be fatal. To address this situation, the use of phages for the treatment of bacterial infections has been extensively studied as an alternative therapeutic strategy. Since Pseudomonas aeruginosa is one of the most common causes of health care-associated infections, many studies have reported the in vitro and in vivo antibacterial efficacy of phage therapy against this bacterium. This review collects data of all the P. aeruginosa phages sequenced to date, providing a better understanding about their biodiversity. This review further addresses the in vitro and in vivo results obtained by using phages to treat or prevent P. aeruginosa infections as well as the major hurdles associated with this therapy. PMID:25972556

  15. Phenazine virulence factor binding to extracellular DNA is important for Pseudomonas aeruginosa biofilm formation

    PubMed Central

    Das, Theerthankar; Kutty, Samuel K.; Tavallaie, Roya; Ibugo, Amaye I.; Panchompoo, Janjira; Sehar, Shama; Aldous, Leigh; Yeung, Amanda W. S.; Thomas, Shane R.; Kumar, Naresh; Gooding, J. Justin; Manefield, Mike

    2015-01-01

    Bacterial resistance to conventional antibiotics necessitates the identification of novel leads for infection control. Interference with extracellular phenomena, such as quorum sensing, extracellular DNA integrity and redox active metabolite release, represents a new frontier to control human pathogens such as Pseudomonas aeruginosa and hence reduce mortality. Here we reveal that the extracellular redox active virulence factor pyocyanin produced by P. aeruginosa binds directly to the deoxyribose-phosphate backbone of DNA and intercalates with DNA nitrogenous base pair regions. Binding results in local perturbations of the DNA double helix structure and enhanced electron transfer along the nucleic acid polymer. Pyocyanin binding to DNA also increases DNA solution viscosity. In contrast, antioxidants interacting with DNA and pyocyanin decrease DNA solution viscosity. Biofilms deficient in pyocyanin production and biofilms lacking extracellular DNA show similar architecture indicating the interaction is important in P. aeruginosa biofilm formation. PMID:25669133

  16. Phage Therapy: a Step Forward in the Treatment of Pseudomonas aeruginosa Infections

    PubMed Central

    Pires, Diana P.; Vilas Boas, Diana; Sillankorva, Sanna

    2015-01-01

    Antimicrobial resistance constitutes one of the major worldwide public health concerns. Bacteria are becoming resistant to the vast majority of antibiotics, and nowadays, a common infection can be fatal. To address this situation, the use of phages for the treatment of bacterial infections has been extensively studied as an alternative therapeutic strategy. Since Pseudomonas aeruginosa is one of the most common causes of health care-associated infections, many studies have reported the in vitro and in vivo antibacterial efficacy of phage therapy against this bacterium. This review collects data of all the P. aeruginosa phages sequenced to date, providing a better understanding about their biodiversity. This review further addresses the in vitro and in vivo results obtained by using phages to treat or prevent P. aeruginosa infections as well as the major hurdles associated with this therapy. PMID:25972556

  17. The innate immune protein calprotectin promotes Pseudomonas aeruginosa and Staphylococcus aureus interaction

    PubMed Central

    Wakeman, Catherine A.; Moore, Jessica L.; Noto, Michael J.; Zhang, Yaofang; Singleton, Marc D.; Prentice, Boone M.; Gilston, Benjamin A.; Doster, Ryan S.; Gaddy, Jennifer A.; Chazin, Walter J.; Caprioli, Richard M.; Skaar, Eric P.

    2016-01-01

    Microorganisms form biofilms containing differentiated cell populations. To determine factors driving differentiation, we herein visualize protein and metal distributions within Pseudomonas aeruginosa biofilms using imaging mass spectrometry. These in vitro experiments reveal correlations between differential protein distribution and metal abundance. Notably, zinc- and manganese-depleted portions of the biofilm repress the production of anti-staphylococcal molecules. Exposure to calprotectin (a host protein known to sequester metal ions at infectious foci) recapitulates responses occurring within metal-deplete portions of the biofilm and promotes interaction between P. aeruginosa and Staphylococcus aureus. Consistent with these results, the presence of calprotectin promotes co-colonization of the murine lung, and polymicrobial communities are found to co-exist in calprotectin-enriched airspaces of a cystic fibrosis lung explant. These findings, which demonstrate that metal fluctuations are a driving force of microbial community structure, have clinical implications because of the frequent occurrence of P. aeruginosa and S. aureus co-infections. PMID:27301800

  18. Major proteomic changes associated with amyloid-induced biofilm formation in Pseudomonas aeruginosa PAO1.

    PubMed

    Herbst, Florian-Alexander; Søndergaard, Mads T; Kjeldal, Henrik; Stensballe, Allan; Nielsen, Per H; Dueholm, Morten S

    2015-01-01

    The newly identified functional amyloids in Pseudomonas (Fap) are associated with increased aggregation and biofilm formation in the opportunistic pathogen P. aeruginosa; however, whether this phenomenon can be simply ascribed to the mechanical properties of the amyloid fibrils remains undetermined. To gain a deeper understanding of the Fap-mediated biofilm formation, the physiological consequences of Fap expression were investigated using label-free protein quantification. The functional amyloids were found to not solely act as inert structural biofilm components. Their presence induced major changes in the global proteome of the bacterium. These included the lowered abundance of classical virulence factors such as elastase B and the secretion system of alkaline protease A. Amyloid-mediated biofilm formation furthermore increased abundance of the alginate and pyoverdine synthesis machinery, which turned P. aeruginosa PAO1 into an unexpected mucoid phenotype. The results imply a significant impact of functional amyloids on the physiology of P. aeruginosa with subsequent implications for biofilm formation and chronic infections.

  19. Comparative study of selective media for enumeration of Pseudomonas aeruginosa from water by membrane filtration.

    PubMed

    de Vicente, A; Borrego, J J; Arrabal, F; Romero, P

    1986-04-01

    In the present study, mPA-D and mPA-E agar, modifications of mPA-C agar that reduce background fecal streptococci that interfere with the differentiation and enumeration of the Pseudomonas aeruginosa colonies grown in other mPA media, are proposed for use in analyzing natural water samples. In addition, the efficiencies of several culture media for the recovery of P. aeruginosa in water after membrane filtration and multiple-tube techniques are compared. The degree of selectivity, precision, efficiency, and sensitivity achieved with the proposed media exceeded that achieved by current methods. Furthermore, they yielded equal rates of accuracy and specificity. Incubation at 36 degrees C resulted in an improved recovery of stressed P. aeruginosa. In conclusion, we propose the use of mPA-D and mPA-E agar, both incubated at 36 degrees C for 24 to 48 h, for analyzing river water and seawater, respectively.

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

    PubMed

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

    2015-02-10

    In the arms race of bacterial pathogenesis, bacteria produce an array of toxins and virulence factors that disrupt core host processes. Hosts mitigate the ensuing damage by responding with immune countermeasures. The iron-binding siderophore pyoverdin is a key virulence mediator of the human pathogen Pseudomonas aeruginosa, but its pathogenic mechanism has not been established. Here we demonstrate that pyoverdin enters Caenorhabditis elegans and that it is sufficient to mediate host killing. Moreover, we show that iron chelation disrupts mitochondrial homeostasis and triggers mitophagy both in C. elegans and mammalian cells. Finally, we show that mitophagy provides protection both against the extracellular pathogen P. aeruginosa and to treatment with a xenobiotic chelator, phenanthroline, in C. elegans. Although autophagic machinery has been shown to target intracellular bacteria for degradation (a process known as xenophagy), our report establishes a role for authentic mitochondrial autophagy in the innate immune defense against P. aeruginosa. PMID:25624506

  1. Pseudomonas aeruginosa Evolutionary Adaptation and Diversification in Cystic Fibrosis Chronic Lung Infections

    PubMed Central

    Winstanley, Craig; O’Brien, Siobhan; Brockhurst, Michael A.

    2016-01-01

    Pseudomonas aeruginosa populations undergo a characteristic evolutionary adaptation during chronic infection of the cystic fibrosis (CF) lung, including reduced production of virulence factors, transition to a biofilm-associated lifestyle, and evolution of high-level antibiotic resistance. Populations of P. aeruginosa in chronic CF lung infections typically exhibit high phenotypic diversity, including for clinically important traits such as antibiotic resistance and toxin production, and this diversity is dynamic over time, making accurate diagnosis and treatment challenging. Population genomics studies reveal extensive genetic diversity within patients, including for transmissible strains the coexistence of highly divergent lineages acquired by patient-to-patient transmission. The inherent spatial structure and spatial heterogeneity of selection in the CF lung appears to play a key role in driving P. aeruginosa diversification. PMID:26946977

  2. Transcriptional Activation of Mucin by Pseudomonas aeruginosa Lipopolysaccharide in the Pathogenesis of Cystic Fibrosis Lung Disease

    NASA Astrophysics Data System (ADS)

    Li, Jian-Dong; Dohrman, Austin F.; Gallup, Marianne; Miyata, Susumu; Gum, James R.; Kim, Young S.; Nadel, Jay A.; Prince, Alice; Basbaum, Carol B.

    1997-02-01

    An unresolved question in cystic fibrosis (CF) research is how mutations of the CF transmembrane conductance regulator, a CI ion channel, cause airway mucus obstruction leading to fatal lung disease. Recent evidence has linked the CF transmembrane conductance regulator mutation to the onset and persistence of Pseudomonas aeruginosa infection in the airways, and here we provide evidence directly linking P. aeruginosa infection to mucus overproduction. We show that P. aeruginosa lipopolysaccharide profoundly upregulates transcription of the mucin gene MUC 2 in epithelial cells via inducible enhancer elements and that this effect is blocked by the tyrosine kinase inhibitors genistein and tyrphostin AG 126. These findings improve our understanding of CF pathogenesis and suggest that the attenuation of mucin production by lipopolysaccharide antagonists and tyrosine kinase inhibitors could reduce morbidity and mortality in this disease.

  3. Evidence for different pyoverdine-mediated iron uptake systems among Pseudomonas aeruginosa strains.

    PubMed Central

    Cornelis, P; Hohnadel, D; Meyer, J M

    1989-01-01

    Fourteen strains of Pseudomonas aeruginosa (P. aeruginosa ATCC 15692, P. aeruginosa ATCC 27853, and 12 clinical isolates) were checked for the production of pyoverdine and for pyoverdine-mediated iron uptake. Under iron restriction, two isolates produced undetectable amounts of pyoverdine, but all the other strains produced a compound with physicochemical properties identical or close to those of the pyoverdine of P. aeruginosa ATCC 15692 (strain PAO1). The pyoverdines were purified and tested for their growth-promoting activity and for their ability to facilitate 59Fe uptake in homologous experiments involving each pyoverdine and its producing strain, as well as in heterologous systems involving all the other strains. The results of both types of experiments suggested the existence of three specificity groups. This was confirmed by analysis of the amino acid composition of the pyoverdines, which differed for each group. A partially purified polyclonal antiserum raised against a major 80-kilodalton (kDa) iron-regulated outer membrane protein (IROMP) of P. aeruginosa PAO1 recognized the 80-kDa IROMPs from P. aeruginosa PAO1 and the clinical isolates belonging to the same group, whereas the IROMPs from the strains belonging to the two other groups were not detected. A second antiserum raised against the P. aeruginosa ATCC 27853 80-kDa IROMP gave similar results by reacting specifically with the 80-kDa IROMP from the strains belonging to this group. Thus, together with the already known pyoverdine from P. aeruginosa PAO1, two new types of pyoverdines produced by strains belonging to this species were characterized. Images PMID:2509364

  4. Inhibition of co-colonizing cystic fibrosis-associated pathogens by Pseudomonas aeruginosa and Burkholderia multivorans.

    PubMed

    Costello, Anne; Reen, F Jerry; O'Gara, Fergal; Callaghan, Máire; McClean, Siobhán

    2014-07-01

    Cystic fibrosis (CF) is a recessive genetic disease characterized by chronic respiratory infections and inflammation causing permanent lung damage. Recurrent infections are caused by Gram-negative antibiotic-resistant bacterial pathogens such as Pseudomonas aeruginosa, Burkholderia cepacia complex (Bcc) and the emerging pathogen genus Pandoraea. In this study, the interactions between co-colonizing CF pathogens were investigated. Both Pandoraea and Bcc elicited potent pro-inflammatory responses that were significantly greater than Ps. aeruginosa. The original aim was to examine whether combinations of pro-inflammatory pathogens would further exacerbate inflammation. In contrast, when these pathogens were colonized in the presence of Ps. aeruginosa the pro-inflammatory response was significantly decreased. Real-time PCR quantification of bacterial DNA from mixed cultures indicated that Ps. aeruginosa significantly inhibited the growth of Burkholderia multivorans, Burkholderia cenocepacia, Pandoraea pulmonicola and Pandoraea apista, which may be a factor in its dominance as a colonizer of CF patients. Ps. aeruginosa cell-free supernatant also suppressed growth of these pathogens, indicating that inhibition was innate rather than a response to the presence of a competitor. Screening of a Ps. aeruginosa mutant library highlighted a role for quorum sensing and pyoverdine biosynthesis genes in the inhibition of B. cenocepacia. Pyoverdine was confirmed to contribute to the inhibition of B. cenocepacia strain J2315. B. multivorans was the only species that could significantly inhibit Ps. aeruginosa growth. B. multivorans also inhibited B. cenocepacia and Pa. apista. In conclusion, both Ps. aeruginosa and B. multivorans are capable of suppressing growth and virulence of co-colonizing CF pathogens.

  5. The Pseudomonas aeruginosa Lipid A Deacylase: Selection for Expression and Loss within the Cystic Fibrosis Airway

    PubMed Central

    Ernst, Robert K.; Adams, Kristin N.; Moskowitz, Samuel M.; Kraig, Gretchen M.; Kawasaki, Kiyoshi; Stead, Christopher M.; Trent, M. Stephen; Miller, Samuel I.

    2006-01-01

    Lipopolysaccharide (LPS) is the major surface component of gram-negative bacteria, and a component of LPS, lipid A, is recognized by the innate immune system through the Toll-like receptor 4/MD-2 complex. Pseudomonas aeruginosa, an environmental gram-negative bacterium that opportunistically infects the respiratory tracts of patients with cystic fibrosis (CF), can synthesize various structures of lipid A. Lipid A from P. aeruginosa strains isolated from infants with CF has a specific structure that includes the removal of the 3 position 3-OH C10 fatty acid. Here we demonstrate increased expression of the P. aeruginosa lipid A 3-O-deacylase (PagL) in isolates from CF infants compared to that in environmental isolates. PagL activity was increased in environmental isolates by growth in medium limited for magnesium and decreased by growth at low temperature in laboratory-adapted strains of P. aeruginosa. P. aeruginosa PagL was shown to be an outer membrane protein by isopycnic density gradient centrifugation. Heterologous expression of P. aeruginosa pagL in Salmonella enterica serovar Typhimurium and Escherichia coli resulted in removal of the 3-OH C14 fatty acid from lipid A, indicating that P. aeruginosa PagL recognizes either 3-OH C10 or 3-OH C14. Finally, deacylated lipid A species were not observed in some clinical P. aeruginosa isolates from patients with severe pulmonary disease, suggesting that loss of PagL function can occur during long-term adaptation to the CF airway. PMID:16352835

  6. A long-chain flavodoxin protects Pseudomonas aeruginosa from oxidative stress and host bacterial clearance.

    PubMed

    Moyano, Alejandro J; Tobares, Romina A; Rizzi, Yanina S; Krapp, Adriana R; Mondotte, Juan A; Bocco, José L; Saleh, Maria-Carla; Carrillo, Néstor; Smania, Andrea M

    2014-02-01

    Long-chain flavodoxins, ubiquitous electron shuttles containing flavin mononucleotide (FMN) as prosthetic group, play an important protective role against reactive oxygen species (ROS) in various microorganisms. Pseudomonas aeruginosa is an opportunistic pathogen which frequently has to face ROS toxicity in the environment as well as within the host. We identified a single ORF, hereafter referred to as fldP (for fl avo d oxin from P . aeruginosa), displaying the highest similarity in length, sequence identity and predicted secondary structure with typical long-chain flavodoxins. The gene was cloned and expressed in Escherichia coli. The recombinant product (FldP) could bind FMN and exhibited flavodoxin activity in vitro. Expression of fldP in P. aeruginosa was induced by oxidative stress conditions through an OxyR-independent mechanism, and an fldP-null mutant accumulated higher intracellular ROS levels and exhibited decreased tolerance to H2O2 toxicity compared to wild-type siblings. The mutant phenotype could be complemented by expression of a cyanobacterial flavodoxin. Overexpression of FldP in a mutT-deficient P. aeruginosa strain decreased H2O2-induced cell death and the hypermutability caused by DNA oxidative damage. FldP contributed to the survival of P. aeruginosa within cultured mammalian macrophages and in infected Drosophila melanogaster, which led in turn to accelerated death of the flies. Interestingly, the fldP gene is present in some but not all P. aeruginosa strains, constituting a component of the P. aeruginosa accessory genome. It is located in a genomic island as part of a self-regulated polycistronic operon containing a suite of stress-associated genes. The collected results indicate that the fldP gene encodes a long-chain flavodoxin, which protects the cell from oxidative stress, thereby expanding the capabilities of P. aeruginosa to thrive in hostile environments. PMID:24550745

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

    PubMed Central

    van Mansfeld, Rosa; de Vrankrijker, Angelica; Brimicombe, Roland; Heijerman, Harry; Teding van Berkhout, Ferdinand; Spitoni, Cristian; Grave, Sanne; van der Ent, Cornelis; Wolfs, Tom; Willems, Rob; Bonten, Marc

    2016-01-01

    Introduction Segregation of patients with cystic fibrosis (CF) was implemented to prevent chronic infection with epidemic Pseudomonas aeruginosa strains with presumed detrimental clinical effects, but its effectiveness has not been carefully evaluated. Methods The effect of strict segregation on the incidence of P. aeruginosa infection in CF patients was investigated through longitudinal protocolized follow-up of respiratory tract infection before and after segregation. In two nested cross-sectional studies in 2007 and 2011 the P. aeruginosa population structure was investigated and clinical parameters were determined in patients with and without infection with the Dutch epidemic P. aeruginosa clone (ST406). Results Of 784 included patients 315 and 382 were at risk for acquiring chronic P. aeruginosa infection before and after segregation. Acquisition rates were, respectively, 0.14 and 0.05 per 1,000 days at risk (HR: 0.66, 95% CI [0.2548–1.541]; p = 0.28). An exploratory subgroup analysis indicated lower acquisition after segregation in children < 15 years of age (HR: 0.43, 95% CI[0.21–0.95]; p = 0.04). P. aeruginosa population structure did not change after segregation and ST406 was not associated with lung function decline, death or lung transplantation. Conclusions Strict segregation was not associated with a statistically significant lower acquisition of chronic P. aeruginosa infection and ST406 was not associated with adverse clinical outcome. After segregation there were no new acquisitions of ST406. In an unplanned exploratory analysis chronic acquisition of P. aeruginosa was lower after implementation of segregation in patients under 15 years of age. PMID:27280467

  8. In Vitro Interaction of Pseudomonas aeruginosa with Human Middle Ear Epithelial Cells

    PubMed Central

    Mittal, Rahul; Grati, M’hamed; Gerring, Robert; Blackwelder, Patricia; Yan, Denise; Li, Jian-Dong; Liu, Xue Zhong

    2014-01-01

    Background Otitis media (OM) is an inflammation of the middle ear which can be acute or chronic. Acute OM is caused by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis whereas Pseudomonas aeruginosa is a leading cause of chronic suppurative otitis media (CSOM). CSOM is a chronic inflammatory disorder of the middle ear characterized by infection and discharge. The survivors often suffer from hearing loss and neurological sequelae. However, no information is available regarding the interaction of P. aeruginosa with human middle ear epithelial cells (HMEECs). Methodology and Findings In the present investigation, we demonstrate that P. aeruginosa is able to enter and survive inside HMEECs via an uptake mechanism that is dependent on microtubule and actin microfilaments. The actin microfilament disrupting agent as well as microtubule inhibitors exhibited significant decrease in invasion of HMEECs by P. aeruginosa. Confocal microscopy demonstrated F-actin condensation associated with bacterial entry. This recruitment of F-actin was transient and returned to normal distribution after bacterial internalization. Scanning electron microscopy demonstrated the presence of bacteria on the surface of HMEECs, and transmission electron microscopy confirmed the internalization of P. aeruginosa located in the plasma membrane-bound vacuoles. We observed a significant decrease in cell invasion of OprF mutant compared to the wild-type strain. P. aeruginosa induced cytotoxicity, as demonstrated by the determination of lactate dehydrogenase levels in culture supernatants of infected HMEECs and by a fluorescent dye-based assay. Interestingly, OprF mutant showed little cell damage compared to wild-type P. aeruginosa. Conclusions and Significance This study deciphered the key events in the interaction of P. aeruginosa with HMEECs in vitro and highlighted the role of bacterial outer membrane protein, OprF, in this process. Understanding the molecular mechanisms in

  9. Heavy metals resistant plasmid-mediated utilization of solar by Pseudomonas aeruginosa AA301.

    PubMed

    Abo-Amer, Aly E; Mohamed, Rehab M

    2006-01-01

    Solar-degrading bacteria, Pseudomonas aeruginosa strains, were isolated from Egyptian soil by Mineral Salt Medium (MSM) supplemented with Solar (motor fuel) from different oil-contaminated sites in Sohag province. The strain AA301 of Pseudomonas aeruginosa showed appreciable growth in MSM medium containing high concentrations of Solar ranging from 0.5 to 3% (v/v), with optimum concentration at 1.5%. Solar was used as a sole carbon source and a source of energy by the bacterium. The ability to degrade Solar was found to be associated with a single 60-kb plasmid designated pSOL15. The plasmid-cured variant, which was obtained by culturing in LB broth with kanamycin, lost the plasmid indicative the ability to degrade Solar must depend on this plasmid. The wild type isolate, Pseudomonas aeruginosa AA301 and transformant strain, have maximum growth (OD600 = approximately 2) on Solar, however the plasmid-cured variant did not have any significant growth on Solar. Moreover, resistance to a wide range of heavy metals such as Mn2+, Hg2+, Mg2+, Cd2+, Zn2+, and Ni2+ was also 60-kb plasmid-mediated. Therefore, the strain AA301 could be good candidate for remediation of some heavy metals and oil hydrocarbons in heavily polluted sites.

  10. Clinical utilization of genomics data produced by the international Pseudomonas aeruginosa consortium.

    PubMed

    Freschi, Luca; Jeukens, Julie; Kukavica-Ibrulj, Irena; Boyle, Brian; Dupont, Marie-Josée; Laroche, Jérôme; Larose, Stéphane; Maaroufi, Halim; Fothergill, Joanne L; Moore, Matthew; Winsor, Geoffrey L; Aaron, Shawn D; Barbeau, Jean; Bell, Scott C; Burns, Jane L; Camara, Miguel; Cantin, André; Charette, Steve J; Dewar, Ken; Déziel, Éric; Grimwood, Keith; Hancock, Robert E W; Harrison, Joe J; Heeb, Stephan; Jelsbak, Lars; Jia, Baofeng; Kenna, Dervla T; Kidd, Timothy J; Klockgether, Jens; Lam, Joseph S; Lamont, Iain L; Lewenza, Shawn; Loman, Nick; Malouin, François; Manos, Jim; McArthur, Andrew G; McKeown, Josie; Milot, Julie; Naghra, Hardeep; Nguyen, Dao; Pereira, Sheldon K; Perron, Gabriel G; Pirnay, Jean-Paul; Rainey, Paul B; Rousseau, Simon; Santos, Pedro M; Stephenson, Anne; Taylor, Véronique; Turton, Jane F; Waglechner, Nicholas; Williams, Paul; Thrane, Sandra W; Wright, Gerard D; Brinkman, Fiona S L; Tucker, Nicholas P; Tümmler, Burkhard; Winstanley, Craig; Levesque, Roger C

    2015-01-01

    The International Pseudomonas aeruginosa Consortium is sequencing over 1000 genomes and building an analysis pipeline for the study of Pseudomonas genome evolution, antibiotic resistance and virulence genes. Metadata, including genomic and phenotypic data for each isolate of the collection, are available through the International Pseudomonas Consortium Database (http://ipcd.ibis.ulaval.ca/). Here, we present our strategy and the results that emerged from the analysis of the first 389 genomes. With as yet unmatched resolution, our results confirm that P. aeruginosa strains can be divided into three major groups that are further divided into subgroups, some not previously reported in the literature. We also provide the first snapshot of P. aeruginosa strain diversity with respect to antibiotic resistance. Our approach will allow us to draw potential links between environmental strains and those implicated in human and animal infections, understand how patients become infected and how the infection evolves over time as well as identify prognostic markers for better evidence-based decisions on patient care. PMID:26483767

  11. Clinical utilization of genomics data produced by the international Pseudomonas aeruginosa consortium

    PubMed Central

    Freschi, Luca; Jeukens, Julie; Kukavica-Ibrulj, Irena; Boyle, Brian; Dupont, Marie-Josée; Laroche, Jérôme; Larose, Stéphane; Maaroufi, Halim; Fothergill, Joanne L.; Moore, Matthew; Winsor, Geoffrey L.; Aaron, Shawn D.; Barbeau, Jean; Bell, Scott C.; Burns, Jane L.; Camara, Miguel; Cantin, André; Charette, Steve J.; Dewar, Ken; Déziel, Éric; Grimwood, Keith; Hancock, Robert E. W.; Harrison, Joe J.; Heeb, Stephan; Jelsbak, Lars; Jia, Baofeng; Kenna, Dervla T.; Kidd, Timothy J.; Klockgether, Jens; Lam, Joseph S.; Lamont, Iain L.; Lewenza, Shawn; Loman, Nick; Malouin, François; Manos, Jim; McArthur, Andrew G.; McKeown, Josie; Milot, Julie; Naghra, Hardeep; Nguyen, Dao; Pereira, Sheldon K.; Perron, Gabriel G.; Pirnay, Jean-Paul; Rainey, Paul B.; Rousseau, Simon; Santos, Pedro M.; Stephenson, Anne; Taylor, Véronique; Turton, Jane F.; Waglechner, Nicholas; Williams, Paul; Thrane, Sandra W.; Wright, Gerard D.; Brinkman, Fiona S. L.; Tucker, Nicholas P.; Tümmler, Burkhard; Winstanley, Craig; Levesque, Roger C.

    2015-01-01

    The International Pseudomonas aeruginosa Consortium is sequencing over 1000 genomes and building an analysis pipeline for the study of Pseudomonas genome evolution, antibiotic resistance and virulence genes. Metadata, including genomic and phenotypic data for each isolate of the collection, are available through the International Pseudomonas Consortium Database (http://ipcd.ibis.ulaval.ca/). Here, we present our strategy and the results that emerged from the analysis of the first 389 genomes. With as yet unmatched resolution, our results confirm that P. aeruginosa strains can be divided into three major groups that are further divided into subgroups, some not previously reported in the literature. We also provide the first snapshot of P. aeruginosa strain diversity with respect to antibiotic resistance. Our approach will allow us to draw potential links between environmental strains and those implicated in human and animal infections, understand how patients become infected and how the infection evolves over time as well as identify prognostic markers for better evidence-based decisions on patient care. PMID:26483767

  12. Controlling methicillin resistant Staphyloccocus aureus and Pseudomonas aeruginosa wound infections with a novel biomaterial.

    PubMed

    Martineau, Lucie; Davis, Stephen C; Peng, Henry T; Hung, Andy

    2007-01-01

    Wound infections, especially those associated with methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, offer considerable challenges for clinicians. Our laboratory has recently developed novel composite biomaterials (DRDC) for wound dressing applications, and demonstrated their in vitro bactericidal efficacy. In the present study, we assessed the proliferation of planktonic and sessile Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus in porcine full-thickness wounds covered for up to 48 h with either saline- or mafenide acetate-loaded DRDC puffs and meshes. All biomaterials were applied 4 h following bacterial inoculation of the wounds with methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, to allow colonization of the tissues and initiation of biofilm formation. The drug-loaded biomaterials eradicated both the planktonic and biofilm bacteria in the wounds within 24 h (p <. 05), irrespective of the bacterial strain or architecture of the dressing. While the wound bioburdens increased in the ensuing 24 h, they remained approximately 2 log(10) colony-forming units (CFU) below (p <. 05) their respective baseline values. Similarly, less than 4 log(10) CFU was recovered in the drug-loaded DRDC biomaterials throughout the study. These data show that the DRDC puffs and meshes are effective in delivering certain medications, such as antimicrobial agents, to the wound bed, suggesting considerable value of this material for treating wounds, especially those with irregular shapes, contours, and depths.

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

    PubMed Central

    Salehi, Bahareh; Mortaz, Esmaeil; Tabarsi, Payam

    2015-01-01

    Background: Inorganic antibacterial factors have bacterial resistance and high thermal stability. Inorganic nanomaterials which have new structures with biological, chemical and physical properties have been made since their applications due to their nano size. In this study, the antibacterial effect of cadmium oxide nanoparticles on Staphylococcus aureus and Pseudomonas aeruginosa bacteria was investigated. Materials and Methods: The different concentrations (10 μg/ml, 15 μg/ml and 20 μg/ml) of cadmium oxide nanoparticles were prepared and their effects were studied against considered bacteria in both solid and liquid media. Results: The results showed that there is a direct relationship between inhibitory effect and amount of consumer dose of nanoparticles. Furthermore, it was observed that antibacterial properties of cadmium oxide nanoparticles on activity and growth of Staphylococcus aureus was more effective than Pseudomonas aeruginosa. Conclusion: This study showed that antibacterial effects of cadmium oxide nanoparticles on positive gram bacteria are stronger than negative gram bacteria and antibacterial effects of cdo nanoparticles against both bacteria, but Staphylococcus aureus bacteria were more sensitive to nanoparticles as compared to Pseudomonas aeruginosa. PMID:26261807

  14. Evaluation of an MPN test for the rapid enumeration of Pseudomonas aeruginosa in hospital waters.

    PubMed

    Sartory, David P; Pauly, Danièle; Garrec, Nathalie; Bonadonna, Lucia; Semproni, Maurizio; Schell, Christiane; Reimann, Annika; Firth, Susan J; Thom, Christopher; Hartemann, Philippe; Exner, Martin; Baldauf, Henning; Lee, Susanne; Lee, John V

    2015-06-01

    In this study, the performance of a new most probable number (MPN) test (Pseudalert(®)/Quanti-Tray(®)) for the enumeration of Pseudomonas aeruginosa from hospital waters was compared with both international and national membrane filtration-based culture methods for P. aeruginosa: ISO 16266:2006 and UK The Microbiology of Drinking Water - Part 8 (MoDW Part 8), which both use Pseudomonas CN agar. The comparison based on the calculation of mean relative differences between the two methods was conducted according to ISO 17994:2014. Using both routine hospital water samples (80 from six laboratories) and artificially contaminated samples (192 from five laboratories), paired counts from each sample and the enumeration method were analysed. For routine samples, there were insufficient data for a conclusive assessment, but the data do indicate at least equivalent performance of Pseudalert(®)/Quanti-Tray(®). For the artificially contaminated samples, the data revealed higher counts of P. aeruginosa being recorded by Pseudalert(®)/Quanti-Tray(®). The Pseudalert(®)/Quanti-Tray(®) method does not require confirmation testing for atypical strains of P. aeruginosa, saving up to 6 days of additional analysis, and has the added advantage of providing confirmed counts within 24-28 hours incubation compared to 40-48 hours or longer for the ISO 16266 and MoDW Part 8 methods.

  15. Pseudomonas aeruginosa PAO-1 Lipopolysaccharide-Diphtheria Toxoid Conjugate Vaccine: Preparation, Characterization and Immunogenicity

    PubMed Central

    Najafzadeh, Faezeh; Shapouri, Reza; Rahnema, Mehdi; Rokhsartalab Azar, Shadi; Kianmehr, Anvarsadat

    2015-01-01

    Background: Treatment of Pseudomonas aeruginosa PAO-1 infections through immunological means has been proved to be efficient and protective. Objectives: The purpose of this study was to produce a conjugate vaccine composed of detoxified lipopolysaccharide (D-LPS) P. aeruginosa and diphtheria toxoid (DT). Materials and Methods: Firstly, LPS was purified and characterized from P. aeruginosa PAO1 and then detoxified. D-LPS was covalently coupled to DT as a carrier protein via amidation method with adipic acid dihydrazide (ADH) as a spacer molecule and 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide (EDAC) as a linker. The molar ratio of LPS to DT in the prepared conjugate was 3:1. The immunogenicity of D-LPS-DT conjugate vaccine in mice model was evaluated as well. Results: The conjugate was devoid of endotoxin activity and 0.125 U/mL of D-LPS was acceptable for immunization. D-LPS-DT conjugate was nonpyrogenic for rabbits and nontoxic for mice. Mice immunization with D-LPS-DT conjugate vaccine elicited the fourfold higher IgG antibody compared to D-LPS. Anti-LPS IgG antibody was predominantly IgG1 subclass and then IgG3, IgG2a and IgG2b, respectively. Conclusions: Vaccine based on the conjugation of P. aeruginosa PAO-1 LPS with DT increased anti-LPS antibodies and had a significant potential to protect against Pseudomonas infections. PMID:26301059

  16. Potent Antibacterial Antisense Peptide–Peptide Nucleic Acid Conjugates Against Pseudomonas aeruginosa

    PubMed Central

    Ghosal, Anubrata

    2012-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen causing severe infections in hospital settings, especially with immune compromised patients, and the increasing prevalence of multidrug resistant strains urges search for new drugs with novel mechanisms of action. In this study we introduce antisense peptide–peptide nucleic acid (PNA) conjugates as antibacterial agents against P. aeruginosa. We have designed and optimized antisense peptide–PNA conjugates targeting the translation initiation region of the ftsZ gene (an essential bacterial gene involved in cell division) or the acpP gene (an essential bacterial gene involved in fatty acid synthesis) of P. aeruginosa (PA01) and characterized these compounds according to their antimicrobial activity and mode of action. Four antisense PNA oligomers conjugated to the H-(R-Ahx-R)4-Ahx-βala or the H-(R-Ahx)6-βala peptide exhibited complete growth inhibition of P. aeruginosa strains PA01, PA14, and LESB58 at 1–2 μM concentrations without any indication of bacterial membrane disruption (even at 20 μM), and resulted in specific reduction of the targeted mRNA levels. One of the four compounds showed clear bactericidal activity while the other significantly reduced bacterial survival. These results open the possibility of development of antisense antibacterials for treatment of Pseudomonas infections. PMID:23030590

  17. Nebulized anticoagulants limit coagulopathy but not inflammation in pseudomonas aeruginosa-induced pneumonia in rats.

    PubMed

    Cornet, Alexander D; Hofstra, Jorrit J; Vlaar, Alexander P; van den Boogaard, Floor E; Roelofs, Joris J; van der Poll, Tom; Levi, Marcel; Groeneveld, A B Johan; Schultz, Marcus J

    2011-10-01

    Disturbed alveolar fibrin turnover is a characteristic feature of pneumonia. Inhibitors of coagulation could exert lung-protective effects via anticoagulant (inhibiting fibrin deposition) and possibly anti-inflammatory pathways, but could also affect host defense. In this randomized controlled in vivo laboratory study, rats were challenged intratracheally with Pseudomonas aeruginosa, inducing pneumonia, and randomized to local treatment with normal saline (placebo), recombinant human activated protein C (rh-APC), plasma-derived antithrombin (AT), heparin, or danaparoid. Induction of P. aeruginosa pneumonia resulted in activation of pulmonary coagulation and inhibition of pulmonary fibrinolysis, as reflected by increased pulmonary levels of thrombin-AT complexes and fibrin degradation products and decreased pulmonary levels plasminogen activator activity. Pseudomonas aeruginosa pneumonia was accompanied by systemic coagulopathy, since systemic levels of thrombin-AT complexes increased, and systemic levels of plasminogen activator activity decreased. Although rh-APC and plasma-derived AT potently limited pulmonary coagulopathy, neither heparin nor danaparoid affected net pulmonary fibrin turnover. Recombinant human APC also displayed systemic anticoagulant effects. Neither bacterial clearance nor pulmonary inflammation was affected by anticoagulant therapy. Nebulization of rh-APC or plasma-derived AT attenuated pulmonary coagulopathy, but not bacterial clearance or inflammation, in a rat model of P. aeruginosa pneumonia. PMID:21897338

  18. Contamination of Hospital Water Supplies in Gilan, Iran, with Legionella pneumophila, Escherichia coli, and Pseudomonas aeruginosa

    PubMed Central

    Ahmadi Jalali Moghadam, Masoumeh; Honarmand, Hamidreza; Asfaram Meshginshahr, Sajad

    2015-01-01

    This study is designed to determine the contamination degree of hospital water supplies with Pseudomonas aeruginosa, Legionella pneumophila, and E. coli in Gilan, Iran. Samples were collected directly into sterile containers and concentrated by centrifuge. Half part of any sample transferred to yeast extract broth and the second part transferred to Trypticase Soy Broth and incubated for 3 days. DNA was extracted by using commercial kit. Four rounds of PCR were performed as follows: multiplex PCR for detecting Pseudomonas aeruginosa, Integron 1, and Metallo-β-lactamases gene; PCR for detecting Legionella pneumophila and mip gene separately; PCR for detecting E. coli; and another PCR for detecting whole bacterial presence. Contamination rates of cold, warm, and incubator water samples with P. aeruginosa, were 16.6%, 37.5%, and 6.8% consequently. Degrees of contamination with L. pneumophila were 3.3%, 9.3%, and 10.9% and with E. coli were zero, 6.2%, and zero. Total bacterial contamination of cold, warm, and incubator water samples was 93.3%, 84.4%, and 89.0% consequently. Metallo-β-lactamases gene was found in 20.0% of all samples. Contamination degree with P. aeruginosa was considerable and with L. pneumophila was moderate. Metallo-β-lactamases gene was found frequently indicating widespread multiple drug resistance bacteria. We suggest using new decontamination method based on nanotechnology. PMID:26448745

  19. ZnO nanoparticles inhibit Pseudomonas aeruginosa biofilm formation and virulence factor production.

    PubMed

    Lee, Jin-Hyung; Kim, Yong-Guy; Cho, Moo Hwan; Lee, Jintae

    2014-12-01

    The opportunistic pathogen Pseudomonas aeruginosa produces a variety of virulence factors, and biofilms of this bacterium are much more resistant to antibiotics than planktonic cells. Thirty-six metal ions have been investigated to identify antivirulence and antibiofilm metal ions. Zinc ions and ZnO nanoparticles were found to markedly inhibit biofilm formation and the production of pyocyanin, Pseudomonas quinolone signal (PQS), pyochelin, and hemolytic activity of P. aeruginosa without affecting the growth of planktonic cells. Transcriptome analyses showed that ZnO nanoparticles induce the zinc cation efflux pump czc operon and several important transcriptional regulators (porin gene opdT and type III repressor ptrA), but repress the pyocyanin-related phz operon, which explains observed phenotypic changes. A mutant study showed that the effects of ZnO nanoparticles on the control of pyocyanin production and biofilm formation require the czc regulator CzcR. In addition, ZnO nanoparticles markedly increased the cellular hydrophilicity of P. aeruginosa cells. Our results support that ZnO nanoparticles are potential antivirulence materials against recalcitrant P. aeruginosa infections and possibly other important pathogens. PMID:24958247

  20. Screening of Lactobacillus spp. for the prevention of Pseudomonas aeruginosa pulmonary infections

    PubMed Central

    2014-01-01

    Background Pseudomonas aeruginosa is an opportunistic pathogen that significantly increases morbidity and mortality in nosocomial infections and cystic fibrosis patients. Its pathogenicity especially relies on the production of virulence factors or resistances to many antibiotics. Since multiplication of antibiotic resistance can lead to therapeutic impasses, it becomes necessary to develop new tools for fighting P. aeruginosa infections. The use of probiotics is one of the ways currently being explored. Probiotics are microorganisms that exert a positive effect on the host’s health and some of them are known to possess antibacterial activities. Since most of their effects have been shown in the digestive tract, experimental data compatible with the respiratory environment are strongly needed. The main goal of this study was then to test the capacity of lactobacilli to inhibit major virulence factors (elastolytic activity and biofilm formation) associated with P. aeruginosa pathogenicity. Results Sixty-seven lactobacilli were isolated from the oral cavities of healthy volunteers. These isolates together with 20 lactobacilli isolated from raw milks, were tested for their capacity to decrease biofilm formation and activity of the elastase produced by P. aeruginosa PAO1. Ten isolates, particularly efficient, were accurately identified using a polyphasic approach (API 50 CHL, mass-spectrometry and 16S/rpoA/pheS genes sequencing) and typed by pulsed-field gel electrophoresis (PFGE). The 8 remaining strains belonging to the L. fermentum (6), L. zeae (1) and L. paracasei (1) species were sensitive to all antibiotics tested with the exception of the intrinsic resistance to vancomycin. The strains were all able to grow in artificial saliva. Conclusion Eight strains belonging to L. fermentum, L. zeae and L. paracasei species harbouring anti-elastase and anti-biofilm properties are potential probiotics for fighting P. aeruginosa pulmonary infections. However, further

  1. A Novel Insight into Dehydroleucodine Mediated Attenuation of Pseudomonas aeruginosa Virulence Mechanism

    PubMed Central

    Mustafi, S.; Veisaga, M. L.; López, L. A.; Barbieri, M. A.

    2015-01-01

    Increasing resistance of Pseudomonas aeruginosa (P. aeruginosa) to conventional treatments demands the search for novel therapeutic strategies. In this study, the antimicrobial activity of dehydroleucodine (DhL), a sesquiterpene lactone obtained from Artemisia (A.) douglasiana, was screened against several pathogenic virulence effectors of P. aeruginosa. In vitro, minimum inhibitory concentration of DhL was determined against P. aeruginosa strains PAO1, PA103, PA14, and multidrug resistant clinical strain, CDN118. Results showed that DhL was active against each strain where PAO1 and PA103 showed higher susceptibility (MIC 0.48 mg/mL) as compared to PA14 (MIC 0.96 mg/mL) and CDN118 (MIC 0.98 mg/mL). Also, when PAO1 strain was grown in the presence of DhL (MIC50, 0.12 mg/mL), a delay in the generation time was noticed along with significant inhibition of secretory protease and elastase activities, interruption in biofilm attachment phase in a stationary culture, and a significant decline in Type III effector ExoS. At MIC50, DhL treatment increased the sensitivity of P. aeruginosa towards potent antibiotics. Furthermore, treatment of P. aeruginosa with DhL prevented toxin-induced apoptosis in macrophages. These observations suggest that DhL activity was at the bacterial transcriptional level. Hence, antimicrobial activity of DhL may serve as leads in the development of new anti-Pseudomonas pharmaceuticals. PMID:26640783

  2. Role of Adherence in the Pathogenesis of Pseudomonas aeruginosa Lung Infection in Cystic Fibrosis Patients

    PubMed Central

    Woods, Donald E.; Bass, Joe A.; Johanson, W. G.; Straus, David C.

    1980-01-01

    A correlation has been demonstrated between the in vitro adherence of Pseudomonas aeruginosa to upper respiratory tract epithelium and colonization of the respiratory tract by this organism. Twenty patients with cystic fibrosis (CF) and 20 age-matched controls were examined in this study. All of the CF patients but none of the controls were colonized with P. aeruginosa at the time of study. P. aeruginosa adherence to isolated epithelial cells, as determined by an in vitro assay, was 19.1 ± 1.1 bacteria per buccal epithelial cell in the CF patients and 2.3 ± 0.3 bacteria per cell in the controls (P < 0.01). P. aeruginosa strains of the mucoid colony type adhered in significantly lower numbers to buccal epithelial cells than did strains of the rough colony type (1.8 + 0.1 versus 24.8 ± 0.9, P < 0.001). This difference might explain the common observation that the initial pseudomonas colonization of the respiratory tract of CF patients is due to organisms of the rough colony type. We have further demonstrated that increased P. aeruginosa adherence in vitro varies directly with the loss of a protease-sensitive glycoprotein, fibronectin, from the cell surface, as well as increased levels of salivary proteases in CF patients. When examined by a direct radioimmune binding assay, buccal cells from CF patients possessed only 17% of the total cell surface fibronectin present on similar cells obtained from controls. Salivary protease levels, as measured by 125I release from an 125I-labeled insoluble fibrin matrix, were increased about threefold in CF patients versus controls. Thus, colonization of the respiratory tract by P. aeruginosa in CF patients correlates well with buccal cell adherence of this organism; increased adherence is associated with decreased amounts of fibronectin on respiratory epithelial cell surfaces and increased levels of salivary proteases. PMID:7014444

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

    NASA Astrophysics Data System (ADS)

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

    1997-10-01

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

  4. Application of bacteriophages to selectively remove Pseudomonas aeruginosa in water and wastewater filtration systems.

    PubMed

    Zhang, Yanyan; Hunt, Heather K; Hu, Zhiqiang

    2013-09-01

    Water and wastewater filtration systems often house pathogenic bacteria, which must be removed to ensure clean, safe water. Here, we determine the persistence of the model bacterium Pseudomonas aeruginosa in two types of filtration systems, and use P. aeruginosa bacteriophages to determine their ability to selectively remove P. aeruginosa. These systems used beds of either anthracite or granular activated carbon (GAC), which were operated at an empty bed contact time (EBCT) of 45 min. The clean bed filtration systems were loaded with an instantaneous dose of P. aeruginosa at a total cell number of 2.3 (± 0.1 [standard deviation]) × 10(7) cells. An immediate dose of P. aeruginosa phages (1 mL of phage stock at the concentration of 2.7 × 10(7) PFU (Plaque Forming Units)/mL) resulted in a reduction of 50% (± 9%) and >99.9% in the effluent P. aeruginosa concentrations in the clean anthracite and GAC filters, respectively. To further evaluate the effects of P. aeruginosa phages, synthetic stormwater was run through anthracite and GAC biofilters where mixed-culture biofilms were present. Eighty five days after an instantaneous dose of P. aeruginosa (2.3 × 10(7) cells per filter) on day 1, 7.5 (± 2.8) × 10(7) and 1.1 (± 0.5) × 10(7) P. aeruginosa cells/g filter media were detected in the top layer (close to the influent port) of the anthracite and GAC biofilters, respectively, demonstrating the growth and persistence of pathogenic bacteria in the biofilters. A subsequent 1-h dose of phages, at the concentration of 5.1 × 10(6) PFU/mL and flow rate of 1.6 mL/min, removed the P. aeruginosa inside the GAC biofilters and the anthracite biofilters by 70% (± 5%) and 56% (± 1%), respectively, with no P. aeruginosa detected in the effluent, while not affecting ammonia oxidation or the ammonia-oxidizing bacterial community inside the biofilters. These results suggest that phage treatment can selectively remove pathogenic bacteria with minimal impact on beneficial

  5. Application of bacteriophages to selectively remove Pseudomonas aeruginosa in water and wastewater filtration systems.

    PubMed

    Zhang, Yanyan; Hunt, Heather K; Hu, Zhiqiang

    2013-09-01

    Water and wastewater filtration systems often house pathogenic bacteria, which must be removed to ensure clean, safe water. Here, we determine the persistence of the model bacterium Pseudomonas aeruginosa in two types of filtration systems, and use P. aeruginosa bacteriophages to determine their ability to selectively remove P. aeruginosa. These systems used beds of either anthracite or granular activated carbon (GAC), which were operated at an empty bed contact time (EBCT) of 45 min. The clean bed filtration systems were loaded with an instantaneous dose of P. aeruginosa at a total cell number of 2.3 (± 0.1 [standard deviation]) × 10(7) cells. An immediate dose of P. aeruginosa phages (1 mL of phage stock at the concentration of 2.7 × 10(7) PFU (Plaque Forming Units)/mL) resulted in a reduction of 50% (± 9%) and >99.9% in the effluent P. aeruginosa concentrations in the clean anthracite and GAC filters, respectively. To further evaluate the effects of P. aeruginosa phages, synthetic stormwater was run through anthracite and GAC biofilters where mixed-culture biofilms were present. Eighty five days after an instantaneous dose of P. aeruginosa (2.3 × 10(7) cells per filter) on day 1, 7.5 (± 2.8) × 10(7) and 1.1 (± 0.5) × 10(7) P. aeruginosa cells/g filter media were detected in the top layer (close to the influent port) of the anthracite and GAC biofilters, respectively, demonstrating the growth and persistence of pathogenic bacteria in the biofilters. A subsequent 1-h dose of phages, at the concentration of 5.1 × 10(6) PFU/mL and flow rate of 1.6 mL/min, removed the P. aeruginosa inside the GAC biofilters and the anthracite biofilters by 70% (± 5%) and 56% (± 1%), respectively, with no P. aeruginosa detected in the effluent, while not affecting ammonia oxidation or the ammonia-oxidizing bacterial community inside the biofilters. These results suggest that phage treatment can selectively remove pathogenic bacteria with minimal impact on beneficial

  6. Post-antibiotic effect of orbifloxacin against Escherichia coli and Pseudomonas aeruginosa isolates from dogs.

    PubMed

    Harada, Kazuki; Shimizu, Takae; Kataoka, Yasushi; Takahashi, Toshio

    2012-03-20

    Orbifloxacin is a fluoroquinolone drug used widely in companion animal medicine. In this study, we firstly determined post-antibiotic effects (PAEs) and post-antibiotic sub-minimum inhibitory concentrations (MIC) effects (PA-SMEs) of orbifloxacin for two strains each of Escherichia coli and Pseudomonas aeruginosa from dogs, and these parameters were compared with those of enrofloxacin. At twice the MIC, the PAEs of orbifloxacin ranged from -0.28-0.93 h (mean, 0.29 h) for E. coli and -0.18-1.18 h (mean, 0.37 h) for P. aeruginosa. These parameters were not significantly different for E. coli and shorter for P. aeruginosa, compared to enrofloxacin (P < 0.05). Continued exposure to 0.1, 0.2, and 0.3 the MIC of orbifloxacin resulted in average PA-SMEs of 0.55, 1.11, and 2.03 h, respectively, for E. coli, and 1.04, 1.40, and 2.47 h, respectively, for P. aeruginosa. These PA-SMEs, which had no significant differences with those of enrofloxacin, were significantly longer than the corresponding PAEs (P < 0.05). These results suggest that the PA-SME of orbifloxacin for E. coli and P. aeruginosa can be meaningfully prolonged by increase of sub-MICs.

  7. Co-incubation of Acanthamoeba castellanii with strains of Pseudomonas aeruginosa alters the survival of amoeba.

    PubMed

    Cengiz, A M; Harmis, N; Stapleton, F

    2000-06-01

    Enhanced survival of Acanthamoeba castellanii has previously been reported following co-incubation with a single strain of Pseudomonas aeruginosa. The aim of this study was to evaluate the impact of different strains of P. aeruginosa on amoebae survival. Four contact lens solutions were challenged with A. castellanii for between 6 and 24 h, and survival rates of amoeba were calculated. Subsequently, A. castellanii was co-incubated with different strains of P. aeruginosa (strain 6294, an invasive isolate; 6206, a cytotoxic isolate; and Paer 001, a null isolate). Differences in amoeba survival over time between solutions for each bacterial strain were analysed. Non-neutralized hydrogen peroxide was the most effective system against A. castellani at all time points (P<0.05). Survival rates were not different between multipurpose solutions and neutralized hydrogen peroxide. Co-incubation with P. aeruginosa altered amoeba survival, and maximum survival occurred in the presence of the invasive strain of P. aeruginosa. Enhanced amoeba survival may occur in the presence of certain strains of Gram-negative bacteria, and with certain types of contact lens disinfection systems.

  8. Physiology and genetic traits of reverse osmosis membrane biofilms: a case study with Pseudomonas aeruginosa.

    PubMed

    Herzberg, Moshe; Elimelech, Menachem

    2008-02-01

    Biofilm formation of Pseudomonas aeruginosa on the surface of a reverse osmosis (RO) membrane was studied using a synthetic wastewater medium to simulate conditions relevant to reclamation of secondary wastewater effluent. P. aeruginosa biofilm physiology and spatial activity were analyzed following growth on the membrane using a short-life green fluorescent protein derivative expressed in a growth-dependent manner. As a consequence of the limiting carbon source prevailing in the suspended culture of the RO unit, a higher distribution of active cells was observed in the biofilm close to the membrane surface, likely due to the higher nutrient levels induced by concentration polarization effects. The faster growth of the RO-sessile cells compared to the planktonic cells in the RO unit was reflected by the transcriptome of the two cultures analyzed with DNA microarrays. In contrast to the findings recently reported in gene expression studies of P. aeruginosa biofilms, in the RO system, genes related to stress, adaptation, chemotaxis and resistance to antibacterial agents were induced in the planktonic cells. In agreement with the findings of previous P. aeruginosa biofilm studies, motility- and attachment-related genes were repressed in the RO P. aeruginosa biofilm. Supported by the microarray data, an increase in both motility and chemotaxis phenotypes was observed in the suspended cells. The increase in nutrient concentration in close proximity to the membrane is suggested to enhance biofouling by chemotaxis response of the suspended cells and their swimming toward the membrane surface.

  9. The Susceptibility of Pseudomonas aeruginosa Strains from Cystic Fibrosis Patients to Bacteriophages

    PubMed Central

    Essoh, Christiane; Blouin, Yann; Loukou, Guillaume; Cablanmian, Arsher; Lathro, Serge; Kutter, Elizabeth; Thien, Hoang Vu; Vergnaud, Gilles; Pourcel, Christine

    2013-01-01

    Phage therapy may become a complement to antibiotics in the treatment of chronic Pseudomonas aeruginosa infection. To design efficient therapeutic cocktails, the genetic diversity of the species and the spectrum of susceptibility to bacteriophages must be investigated. Bacterial strains showing high levels of phage resistance need to be identified in order to decipher the underlying mechanisms. Here we have selected genetically diverse P. aeruginosa strains from cystic fibrosis patients and tested their susceptibility to a large collection of phages. Based on plaque morphology and restriction profiles, six different phages were purified from “pyophage”, a commercial cocktail directed against five different bacterial species, including P. aeruginosa. Characterization of these phages by electron microscopy and sequencing of genome fragments showed that they belong to 4 different genera. Among 47 P. aeruginosa strains, 13 were not lysed by any of the isolated phages individually or by pyophage. We isolated two new phages that could lyse some of these strains, and their genomes were sequenced. The presence/absence of a CRISPR-Cas system (Clustered Regularly Interspaced Short Palindromic Repeats and Crisper associated genes) was investigated to evaluate the role of the system in phage resistance. Altogether, the results show that some P. aeruginosa strains cannot support the growth of any of the tested phages belonging to 5 different genera, and suggest that the CRISPR-Cas system is not a major defence mechanism against these lytic phages. PMID:23637754

  10. The susceptibility of Pseudomonas aeruginosa strains from cystic fibrosis patients to bacteriophages.

    PubMed

    Essoh, Christiane; Blouin, Yann; Loukou, Guillaume; Cablanmian, Arsher; Lathro, Serge; Kutter, Elizabeth; Thien, Hoang Vu; Vergnaud, Gilles; Pourcel, Christine

    2013-01-01

    Phage therapy may become a complement to antibiotics in the treatment of chronic Pseudomonas aeruginosa infection. To design efficient therapeutic cocktails, the genetic diversity of the species and the spectrum of susceptibility to bacteriophages must be investigated. Bacterial strains showing high levels of phage resistance need to be identified in order to decipher the underlying mechanisms. Here we have selected genetically diverse P. aeruginosa strains from cystic fibrosis patients and tested their susceptibility to a large collection of phages. Based on plaque morphology and restriction profiles, six different phages were purified from "pyophage", a commercial cocktail directed against five different bacterial species, including P. aeruginosa. Characterization of these phages by electron microscopy and sequencing of genome fragments showed that they belong to 4 different genera. Among 47 P. aeruginosa strains, 13 were not lysed by any of the isolated phages individually or by pyophage. We isolated two new phages that could lyse some of these strains, and their genomes were sequenced. The presence/absence of a CRISPR-Cas system (Clustered Regularly Interspaced Short Palindromic Repeats and Crisper associated genes) was investigated to evaluate the role of the system in phage resistance. Altogether, the results show that some P. aeruginosa strains cannot support the growth of any of the tested phages belonging to 5 different genera, and suggest that the CRISPR-Cas system is not a major defence mechanism against these lytic phages.

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

    PubMed

    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.

  12. Community-based interference against integration of Pseudomonas aeruginosa into human salivary microbial biofilm.

    PubMed

    He, X; Hu, W; He, J; Guo, L; Lux, R; Shi, W

    2011-12-01

    As part of the human gastrointestinal tract, the oral cavity represents a complex biological system and harbors diverse bacterial species. Unlike the gut microbiota, which is often considered a health asset, studies of the oral commensal microbiota have been largely limited to their implication in oral conditions such as dental caries and periodontal disease. Less emphasis has been given to their potential beneficial roles, especially the protective effects against oral colonization by foreign or pathogenic bacteria. In this study, we used salivary microbiota derived from healthy human subjects to investigate protective effects against colonization and integration of Pseudomonas aeruginosa, an opportunistic bacterial pathogen, into developing or pre-formed salivary biofilms. When co-cultivated in saliva medium, P. aeruginosa persisted in the planktonic phase, but failed to integrate into the salivary microbial community during biofilm formation. Furthermore, in saliva medium supplemented with sucrose, the oral microbiota inhibited the growth of P. aeruginosa by producing lactic acid. More interestingly, while pre-formed salivary biofilms were able to prevent P. aeruginosa colonization, the same biofilms recovered from mild chlorhexidine gluconate treatment displayed a shift in microbial composition and showed a drastic reduction in protection. Our study indicates that normal oral communities with balanced microbial compositions could be important in effectively preventing the integration of foreign or pathogenic bacterial species, such as P. aeruginosa. PMID:22053962

  13. Anthranilate Deteriorates the Structure of Pseudomonas aeruginosa Biofilms and Antagonizes the Biofilm-Enhancing Indole Effect

    PubMed Central

    Kim, Soo-Kyoung; Park, Ha-Young

    2015-01-01

    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. PMID:25616795

  14. Pseudomonas aeruginosa and Heterotrophic Bacteria Count in Bottled Waters in Iran

    PubMed Central

    MOHAMMADI KOUCHESFAHANI, Matin; ALIMOHAMMADI, Mahmood; NABIZADEH NODEHI, Ramin; ASLANI, Hassan; REZAIE, Sassan; ASADIAN, Samieh

    2015-01-01

    Background: Nowadays, due to increased public awareness about water pollution and water borne diseases as well as water network deficiencies, bottled water consumers have increased dramatically worldwide, including Iran. Pseudomonas aeruginosa is an opportunistic human pathogen capable of causing widespread infections in burn and immune-compromised patients. The aim of this study was to investigate, P. aeruginosa in bottled waters selling in Iranian markets. Methods: One hundred and twenty samples of five unknown (not famous) domestic bottled water brands were purchased from Tehran retailers during 2013. The samples were evaluated for the presence of P. aeruginosa. In addition, heterotrophic plate counts were determined by incubation at 37 °C for 24 h. Results: P. aeruginosa was detected in 36.7% (44 samples) of all samples examined. In addition, heterotrophic bacteria in 32.5% (39 samples) of the samples were higher than 100 CFU/mL, while in 7.5% (9 samples) of the samples HPC relied between 20 and 100 CFU/ml. Conclusion: In contrast to public believe, bottled waters are not free of microorganisms, and it is suggested that authorities should provide stricter monitoring and control plan for water resources and plants. Concerning HPC and P. aeruginosa brands B and D were not suitable for drinking. PMID:26744709

  15. A comparative study of coastal and clinical isolates of Pseudomonas aeruginosa.

    PubMed

    Nair, Anusree V; Joseph, Neetha; Krishna, Kiran; Sneha, K G; Tom, Neenu; Jangid, Kamlesh; Nair, Shanta

    2015-01-01

    Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium having a versatile metabolic potential and great ecological and clinical significance. The geographical distribution of P. aeruginosahas revealed the existence of an unbiased genetic arrangement in terrestrial isolates. In contrast, there are very few reports about P. aeruginosa strains from marine environments. The present work was aimed at studying the distribution of P. aeruginosa in coastal waters along the Indian Peninsula and understanding the environmental influence on genotypic, metabolic and phenotypic characteristics by comparing marine and clinical isolates. Of the 785 marine isolates obtained on selective media, only 32 (~4.1%) were identified as P. aeruginosa, based on their fatty acid methyl ester profiles. A low Euclidian distance value (< 2.5) obtained from chemotaxonomic analysis suggested that all the environmental (coastal and marine) isolates originated from a single species. While UPGMA analyses of AP-PCR and phenotypic profiles separated the environmental and clinical isolates, fatty acid biotyping showed overlapping between most clinical and environmental isolates. Our study revealed the genetic diversity among different environmental isolates of P. aeruginosa. While biogeographical separation was not evident based solely on phenotypic and metabolic typing, genomic and metatranscriptomic studies are more likely to show differences between these isolates. Thus, newer and more insightful methods are required to understand the ecological distribution of this complex group of bacteria. PMID:26413053

  16. Characterization of Toxin-Antitoxin (TA) Systems in Pseudomonas aeruginosa Clinical Isolates in Iran

    PubMed Central

    Savari, Mohammad; Rostami, Soodabeh; Ekrami, Alireza; Bahador, Abbas

    2016-01-01

    Background: Pseudomonas aeruginosa is among the most problematic hospital and community-acquired pathogens. Toxin-antitoxin (TA) systems are maintenance regulatory systems in bacteria and have recently been considered new targets for antimicrobial therapy. The prevalence and transcription of these systems in clinical isolates are still unknown. Objectives: The aim of this study was to characterize three types of TA systems (parDE, relBE, and higBA) among P. aeruginosa clinical isolates. Materials and Methods: We typed our clinical isolates by ERIC-PCR (enterobacterial repetitive intergenic consensus sequence-based polymerase chain reaction) and BOX-PCR. We then investigated 174 P. aeruginosa clinical isolates from three hospitals in Ahvaz, Iran, for the presence of TA system genes, and determined whether these systems were encoded on chromosomes or plasmids by amplification of the flanking regions. Results: Our results showed that in the 174 P. aeruginosa isolates, relBE and higBA were universal, but parDE was less prevalent. Both of the flanking regions of the parDE genes in all positive isolates were amplified. The flanking regions of nearly all relBE genes were amplified. Amplification was observed for the downstream sequence of every higBA locus, as well as for the region upstream of higBA, except in 14 strains. Conclusions: Based on the presence of TA systems in the majority of P. aeruginosa isolates, these could be used as a novel target for antimicrobial therapy. PMID:27099681

  17. Flagellin Delivery by Pseudomonas aeruginosa Rhamnolipids Induces the Antimicrobial Protein Psoriasin in Human Skin

    PubMed Central

    Meyer-Hoffert, Ulf; Zimmermann, Alexandra; Czapp, Manfred; Bartels, Joachim; Koblyakova, Yulia; Gläser, Regine; Schröder, Jens-Michael; Gerstel, Ulrich

    2011-01-01

    The opportunistic pathogen Pseudomonas aeruginosa can cause severe infections in patients suffering from disruption or disorder of the skin barrier as in burns, chronic wounds, and after surgery. On healthy skin P. aeruginosa causes rarely infections. To gain insight into the interaction of the ubiquitous bacterium P. aeruginosa and healthy human skin, the induction of the antimicrobial protein psoriasin by P. aeruginosa grown on an ex vivo skin model was analyzed. We show that presence of the P. aeruginosa derived biosurfactant rhamnolipid was indispensable for flagellin-induced psoriasin expression in human skin, contrary to in vitro conditions. The importance of the bacterial virulence factor flagellin as the major inducing factor of psoriasin expression in skin was demonstrated by use of a flagellin-deficient mutant. Rhamnolipid mediated shuttle across the outer skin barrier was not restricted to flagellin since rhamnolipids enable psoriasin expression by the cytokines IL-17 and IL-22 after topical application on human skin. Rhamnolipid production was detected for several clinical strains and the formation of vesicles was observed under skin physiological conditions. In conclusion we demonstrate herein that rhamnolipids enable the induction of the antimicrobial protein psoriasin by flagellin in human skin without direct contact of bacteria and responding cells. Hereby, human skin might control the microflora to prevent colonization of unwanted microbes in the earliest steps before potential pathogens can develop strategies to subvert the immune response. PMID:21283546

  18. Identification of Novel Genomic Islands in Liverpool Epidemic Strain of Pseudomonas aeruginosa Using Segmentation and Clustering.

    PubMed

    Jani, Mehul; Mathee, Kalai; Azad, Rajeev K

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen implicated in a myriad of infections and a leading pathogen responsible for mortality in patients with cystic fibrosis (CF). Horizontal transfers of genes among the microorganisms living within CF patients have led to highly virulent and multi-drug resistant strains such as the Liverpool epidemic strain of P. aeruginosa, namely the LESB58 strain that has the propensity to acquire virulence and antibiotic resistance genes. Often these genes are acquired in large clusters, referred to as "genomic islands (GIs)." To decipher GIs and understand their contributions to the evolution of virulence and antibiotic resistance in P. aeruginosa LESB58, we utilized a recursive segmentation and clustering procedure, presented here as a genome-mining tool, "GEMINI." GEMINI was validated on experimentally verified islands in the LESB58 strain before examining its potential to decipher novel islands. Of the 6062 genes in P. aeruginosa LESB58, 596 genes were identified to be resident on 20 GIs of which 12 have not been previously reported. Comparative genomics provided evidence in support of our novel predictions. Furthermore, GEMINI unraveled the mosaic structure of islands that are composed of segments of likely different evolutionary origins, and demonstrated its ability to identify potential strain biomarkers. These newly found islands likely have contributed to the hyper-virulence and multidrug resistance of the Liverpool epidemic strain of P. aeruginosa.

  19. Clonal Relatedness among Imipenem-Resistant Pseudomonas aeruginosa Isolated from ICU-Hospitalized Patients

    PubMed Central

    Vaez, Hamid; Moghim, Sharareh; Nasr Esfahani, Bahram; Ghasemian Safaei, Hajieh

    2015-01-01

    Imipenem-resistant Pseudomonas aeruginosa (P. aeruginosa) has become an increasingly important problem in healthcare settings worldwide. The aim of the present study was to evaluate clonal spread among imipenem-resistant P. aeruginosa isolated from ICU-hospitalized patients. Totally, 150 wound specimens were analyzed. Antibiotic resistance profiles and clonal diversity were evaluated using Kirby-Bauer's disk diffusion method and Random Amplified Polymorphic DNA- (RAPD-) PCR, respectively. The isolates showed a high frequency of antibiotic resistance against meropenem, and imipenem (100%) followed by ciprofloxacin, and ceftazidime (90%); meanwhile resistance to polymyxin B was not observed. Eighteen (40%) of P. aeruginosa isolates were MBL-positive via ethylenediaminetetraacetic acid (EDTA) combined disk test. Our findings showed high genetic diversity, with 37 different RAPD types detected. RAPD typing results showed cross-acquisition of P. aeruginosa in investigated hospital, suggesting failure in infection control practices. Incidence of MBL-positive isolates is high and should be regarded as a threat to hospitalized patients. PMID:26798509

  20. The occurrence of multidrug-resistant Pseudomonas aeruginosa on hydrocarbon-contaminated sites.

    PubMed

    Kaszab, Edit; Kriszt, Balázs; Atzél, Béla; Szabó, Gabriella; Szabó, István; Harkai, Péter; Szoboszlay, Sándor

    2010-01-01

    The main aim of this paper was the comprehensive estimation of the occurrence rate and the antibiotic-resistance conditions of opportunistic pathogen Pseudomonas aeruginosa in hydrocarbon-contaminated environments. From 2002 to 2007, 26 hydrocarbon-contaminated sites of Hungary were screened for the detection of environmental isolates. Altogether, 156 samples were collected and examined for the determination of appearance, representative cell counts, and antibiotic-resistance features of P. aeruginosa. The detected levels of minimal inhibitory concentrations of ten different drugs against 36 environmental strains were compared to the results of a widely used reference strain ATCC 27853 and four other clinical isolates of P. aeruginosa. Based on our long-term experiment, it can be established that species P. aeruginosa was detectable in case of 61.5% of the investigated hydrocarbon-contaminated sites and 35.2% of the examined samples that shows its widespread occurrence in polluted soil-groundwater systems. In the course of the antibiotic-resistance assay, our results determined that 11 of the examined 36 environmental strains had multiple drug-resistance against several clinically effective antimicrobial classes: cephalosporins, wide spectrum penicillins, carbapenems, fluoroquinolones, and aminoglycosides. The fact that these multiresistant strains were isolated from 8 different hydrocarbon-contaminated sites, mainly from outskirts, confirms that multiple drug-resistance of P. aeruginosa is widespread not only in clinical, but also in natural surroundings as well. PMID:19597862

  1. Modulation of antibiotic resistance and induction of a stress response in Pseudomonas aeruginosa by silver nanoparticles.

    PubMed

    Markowska, Katarzyna; Grudniak, Anna M; Krawczyk, Krzysztof; Wróbel, Izabela; Wolska, Krystyna I

    2014-06-01

    The objective of this study was to characterize the effects of silver nanoparticles on Pseudomonas aeruginosa. Their interactions with several conventional antibiotics and ability to induce a stress response were examined. Interactions between silver nanoparticles (AgNPs) and antibiotics against free-living cells and biofilm of P. aeruginosa were studied using the chequerboard method and time-kill assays. The ability of AgNPs to induce a stress response was determined by evaluation of cellular levels of the DnaK and HtpG chaperones using SDS-PAGE and Western blot analysis. Synergistic activity against free-living P. aeruginosa between AgNPs and ampicillin, streptomycin, rifampicin and tetracycline, but not oxacillin, ciprofloxacin, meropenem or ceftazidime, was demonstrated by the chequerboard method. No such interactions were observed against P. aeruginosa biofilm. The results of time-kill assays confirmed synergy only for the AgNPs-streptomycin combination. AgNPs induced the expression of chaperone DnaK. No induction of the HtpG chaperone was detected. In conclusion, AgNPs not only display potent bactericidal activity against P. aeruginosa, but also act synergistically with several conventional antibiotics to enhance their effect against free-living bacteria as determined by the chequerboard method. The time-kill assay proved synergy between AgNPs and streptomycin only. The ability of AgNPs to induce the major chaperone protein DnaK may influence bacterial resistance to antimicrobials.

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

    PubMed Central

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

    1994-01-01

    In Pseudomonas aeruginosa the LasR protein is required for activation of lasB and several other virulence genes. A diffusible signal molecule, the P. aeruginosa autoinducer (PAI), produced by the bacterial cell and released into the growth medium, is required for activity of LasR. By cloning a lasB::lacZ fusion and a lasR gene under control of the lac promoter in Escherichia coli, we have developed a quantitative bioassay for PAI. We have used this assay to follow the purification of PAI from cell-free culture supernatant fluids in which P. aeruginosa or E. coli containing the P. aeruginosa gene required for autoinducer synthesis, lasI, had been grown. Chemical analyses indicated the purified material was 3-oxo-N-(tetrahydro-2-oxo-3-furanyl)dodecanamide. To confirm this assignment, the compound was synthesized and the synthetic compound was shown to have chemical and biological properties identical to those of PAI purified from culture supernatant fluids. The elucidation of the PAI structure suggests therapeutic approaches toward control of P. aeruginosa infections. PMID:8278364

  3. Identification of Novel Genomic Islands in Liverpool Epidemic Strain of Pseudomonas aeruginosa Using Segmentation and Clustering

    PubMed Central

    Jani, Mehul; Mathee, Kalai; Azad, Rajeev K.

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen implicated in a myriad of infections and a leading pathogen responsible for mortality in patients with cystic fibrosis (CF). Horizontal transfers of genes among the microorganisms living within CF patients have led to highly virulent and multi-drug resistant strains such as the Liverpool epidemic strain of P. aeruginosa, namely the LESB58 strain that has the propensity to acquire virulence and antibiotic resistance genes. Often these genes are acquired in large clusters, referred to as “genomic islands (GIs).” To decipher GIs and understand their contributions to the evolution of virulence and antibiotic resistance in P. aeruginosa LESB58, we utilized a recursive segmentation and clustering procedure, presented here as a genome-mining tool, “GEMINI.” GEMINI was validated on experimentally verified islands in the LESB58 strain before examining its potential to decipher novel islands. Of the 6062 genes in P. aeruginosa LESB58, 596 genes were identified to be resident on 20 GIs of which 12 have not been previously reported. Comparative genomics provided evidence in support of our novel predictions. Furthermore, GEMINI unraveled the mosaic structure of islands that are composed of segments of likely different evolutionary origins, and demonstrated its ability to identify potential strain biomarkers. These newly found islands likely have contributed to the hyper-virulence and multidrug resistance of the Liverpool epidemic strain of P. aeruginosa. PMID:27536294

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

    PubMed Central

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

    2015-01-01

    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

  5. Gene algD coding for GDPmannose dehydrogenase is transcriptionally activated in mucoid Pseudomonas aeruginosa.

    PubMed Central

    Deretic, V; Gill, J F; Chakrabarty, A M

    1987-01-01

    Transcriptional regulation of alginate biosynthesis by Pseudomonas aeruginosa was studied. A DNA region complementing the alg-5 mutation within the alginate gene cluster was found by RNA-DNA dot blot and Northern hybridization to be transcriptionally activated in mucoid P. aeruginosa. This region was subcloned as a 3.2-kilobase BglII-ClaI DNA fragment on the broad-host-range controlled transcription vector pMMB24, and gene products were analyzed by expression from the tac promoter. A 48-kilodalton polypeptide was detected in extracts of P. aeruginosa and 35S-labeled Escherichia coli maxicells. By using the same expression system, GDPmannose dehydrogenase activity was detected in both P. aeruginosa and E. coli. Thus, gene algD coding for this enzyme was found to be present in the transcriptionally active DNA area. Insertion of the xylE gene within the BglII-ClaI fragment disrupted the induction of the 48-kilodalton polypeptide, GDPmannose dehydrogenase activity, and alg-5 complementing ability. With the algD-xylE transcription fusion, activation of algD gene expression was shown to occur in mucoid P. aeruginosa of different origins. In addition, regulation of the algD promoter activity was demonstrated to be mediated by a diffusible factor. Images PMID:3025179

  6. The Pseudomonas aeruginosa AlgZR two-component system coordinates multiple phenotypes

    PubMed Central

    Okkotsu, Yuta; Little, Alexander S.; Schurr, Michael J.

    2014-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that causes a multitude of infections. These infections can occur at almost any site in the body and are usually associated with a breach of the innate immune system. One of the prominent sites where P. aeruginosa causes chronic infections is within the lungs of cystic fibrosis patients. P. aeruginosa uses two-component systems that sense environmental changes to differentially express virulence factors that cause both acute and chronic infections. The P. aeruginosa AlgZR two component system is one of its global regulatory systems that affects the organism's fitness in a broad manner. This two-component system is absolutely required for two P. aeruginosa phenotypes: twitching motility and alginate production, indicating its importance in both chronic and acute infections. Additionally, global transcriptome analyses indicate that it regulates the expression of many different genes, including those associated with quorum sensing, type IV pili, type III secretion system, anaerobic metabolism, cyanide and rhamnolipid production. This review examines the complex AlgZR regulatory network, what is known about the structure and function of each protein, and how it relates to the organism's ability to cause infections. PMID:24999454

  7. A comparative study of coastal and clinical isolates of Pseudomonas aeruginosa

    PubMed Central

    Nair, Anusree V.; Joseph, Neetha; Krishna, Kiran; Sneha, K. G.; Tom, Neenu; Jangid, Kamlesh; Nair, Shanta

    2015-01-01

    Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium having a versatile metabolic potential and great ecological and clinical significance. The geographical distribution of P. aeruginosahas revealed the existence of an unbiased genetic arrangement in terrestrial isolates. In contrast, there are very few reports about P. aeruginosa strains from marine environments. The present work was aimed at studying the distribution of P. aeruginosa in coastal waters along the Indian Peninsula and understanding the environmental influence on genotypic, metabolic and phenotypic characteristics by comparing marine and clinical isolates. Of the 785 marine isolates obtained on selective media, only 32 (~4.1%) were identified as P. aeruginosa, based on their fatty acid methyl ester profiles. A low Euclidian distance value (< 2.5) obtained from chemotaxonomic analysis suggested that all the environmental (coastal and marine) isolates originated from a single species. While UPGMA analyses of AP-PCR and phenotypic profiles separated the environmental and clinical isolates, fatty acid biotyping showed overlapping between most clinical and environmental isolates. Our study revealed the genetic diversity among different environmental isolates of P. aeruginosa. While biogeographical separation was not evident based solely on phenotypic and metabolic typing, genomic and metatranscriptomic studies are more likely to show differences between these isolates. Thus, newer and more insightful methods are required to understand the ecological distribution of this complex group of bacteria. PMID:26413053

  8. Community-based interference against integration of Pseudomonas aeruginosa into human salivary microbial biofilm.

    PubMed

    He, X; Hu, W; He, J; Guo, L; Lux, R; Shi, W

    2011-12-01

    As part of the human gastrointestinal tract, the oral cavity represents a complex biological system and harbors diverse bacterial species. Unlike the gut microbiota, which is often considered a health asset, studies of the oral commensal microbiota have been largely limited to their implication in oral conditions such as dental caries and periodontal disease. Less emphasis has been given to their potential beneficial roles, especially the protective effects against oral colonization by foreign or pathogenic bacteria. In this study, we used salivary microbiota derived from healthy human subjects to investigate protective effects against colonization and integration of Pseudomonas aeruginosa, an opportunistic bacterial pathogen, into developing or pre-formed salivary biofilms. When co-cultivated in saliva medium, P. aeruginosa persisted in the planktonic phase, but failed to integrate into the salivary microbial community during biofilm formation. Furthermore, in saliva medium supplemented with sucrose, the oral microbiota inhibited the growth of P. aeruginosa by producing lactic acid. More interestingly, while pre-formed salivary biofilms were able to prevent P. aeruginosa colonization, the same biofilms recovered from mild chlorhexidine gluconate treatment displayed a shift in microbial composition and showed a drastic reduction in protection. Our study indicates that normal oral communities with balanced microbial compositions could be important in effectively preventing the integration of foreign or pathogenic bacterial species, such as P. aeruginosa.

  9. Random amplified polymorphic DNA typing of Pseudomonas aeruginosa isolates recovered from patients with cystic fibrosis.

    PubMed Central

    Mahenthiralingam, E; Campbell, M E; Foster, J; Lam, J S; Speert, D P

    1996-01-01

    Pseudomonas aeruginosa isolates recovered from chronically colonized patients with cystic fibrosis (CF) are phenotypically different from those collected from other patients or from the environment. To assess whether alterations in motility, mucoidy, and serum susceptibility represented an adaptation to chronic infection or replacement by a new strain, sequential P. aeruginosa isolates of known phenotype collected from 20 CF patients were typed by random amplified polymorphic DNA (RAPD) analysis. A total of 35 RAPD strain types were found among 385 isolates from 20 patients, and only two patients had P. aeruginosa strains of the same RAPD fingerprint. Eight strain pairs representative of the first eight RAPD types were also analyzed by SpeI macrorestriction followed by pulsed-field gel electrophoresis (PFGE); the strain types found by both fingerprinting techniques correlated exactly. In 11 of 20 patients, the RAPD types of serial P. aeruginosa isolates remained stable despite alterations in isolate motility, colonial morphology, and lipopolysaccharide phenotype. However, in isolates collected from one CF patient, a single band change in RAPD fingerprint and CeuI PFGE profile correlated with the appearance of an RpoN mutant phenotype, suggesting that the altered phenotype may have been due to a stable genomic rearrangement. Secretion of mucoid exopolysaccharide, loss of expression of RpoN-dependent surface factors, and acquisition of a serum-susceptible phenotype in P. aeruginosa appear to evolve during chronic colonization in CF patients from specific adaptation to infection rather than from acquisition of new bacterial strains. PMID:8727889

  10. Use of intestinal Pseudomonas aeruginosa in fish to detect the environmental pollutant benzo[a]pyrene.

    PubMed

    Karami, Ali; Christianus, Annie; Ishak, Zamri; Shamsuddin, Zulkifli Hj; Masoumian, Majid; Courtenay, Simon C

    2012-05-15

    This study examined the potential of Pseudomonas aeruginosa abundance in the intestines of fish as an indicator of exposure to benzo[a]pyrene (BaP). P. aeruginosa populations were enumerated in juvenile African catfish (Clarias gariepinus) injected intramuscularly three days previous with 0, 10, 30, 40, 50 or 70mg/kg of BaP. Hepatic EROD and GST activities and biliary fluorescent aromatic compounds (FACs) 1-OH BaP, 3-OH BaP, 7,8-D BaP and BaP were quantified to investigate agreements between the new indicator and established fish biomarkers. The shape of bacterial population (logarithm of colony-forming unit) dose-response curve generally matched those of biliary FACs concentrations. Conversely, the EROD and GST dose-response curves were generally the mirror images of the bacterial population curve. Changes in intestinal P. aeruginosa population appear to be an indirect effect of BaP exposure because exposure to 0-100μg/ml BaP had no effect on P. aeruginosa populations grown on agar plates containing BaP. Using intestinal P. aeruginosa population of fish as a universal indicator of BaP pollution in aquatic environments is discussed.Conversely, the EROD and GST dose-response curves were generally the mirror images of the bacterial population curve.

  11. Development and evaluation of a new PCR assay for detection of Pseudomonas aeruginosa D genotype.

    PubMed

    Lødeng, A G G; Ahlén, C; Lysvand, H; Mandal, L H; Iversen, O J

    2006-08-01

    This report describes a new PCR-based assay for the detection of Pseudomonas aeruginosa genotype D in occupational saturation diving systems in the North Sea. This genotype has persisted in these systems for 11 years (1993-2003) and represents 18% of isolates from infections analysed during this period. The new PCR assay was based on sequences obtained after randomly amplified polymorphic DNA (RAPD)-PCR analysis of a group of isolates related to diving that had been identified previously by pulsed-field gel electrophoresis (PFGE). The primer set for the D genotype targets a gene that codes for a hypothetical class 4 protein in the P. aeruginosa PAO1 genome. A primer set able to detect P. aeruginosa at the species level was also designed, based on the 23S-5S rDNA spacer region. The two assays produced 382-bp and 192-bp amplicons, respectively. The PCR assay was evaluated by analysing 100 P. aeruginosa isolates related to diving, representing 28 PFGE genotypes, and 38 clinical and community P. aeruginosa isolates and strains from other species. The assay identified all of the genotype D isolates tested. Two additional diving-relevant genotypes (TP2 and TP27) were also identified, as well as three isolates of non-diving origin. It was concluded that the new PCR assay is a useful tool for early detection and prevention of infections with the D genotype. PMID:16842571

  12. Identification of Novel Genomic Islands in Liverpool Epidemic Strain of Pseudomonas aeruginosa Using Segmentation and Clustering.

    PubMed

    Jani, Mehul; Mathee, Kalai; Azad, Rajeev K

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen implicated in a myriad of infections and a leading pathogen responsible for mortality in patients with cystic fibrosis (CF). Horizontal transfers of genes among the microorganisms living within CF patients have led to highly virulent and multi-drug resistant strains such as the Liverpool epidemic strain of P. aeruginosa, namely the LESB58 strain that has the propensity to acquire virulence and antibiotic resistance genes. Often these genes are acquired in large clusters, referred to as "genomic islands (GIs)." To decipher GIs and understand their contributions to the evolution of virulence and antibiotic resistance in P. aeruginosa LESB58, we utilized a recursive segmentation and clustering procedure, presented here as a genome-mining tool, "GEMINI." GEMINI was validated on experimentally verified islands in the LESB58 strain before examining its potential to decipher novel islands. Of the 6062 genes in P. aeruginosa LESB58, 596 genes were identified to be resident on 20 GIs of which 12 have not been previously reported. Comparative genomics provided evidence in support of our novel predictions. Furthermore, GEMINI unraveled the mosaic structure of islands that are composed of segments of likely different evolutionary origins, and demonstrated its ability to identify potential strain biomarkers. These newly found islands likely have contributed to the hyper-virulence and multidrug resistance of the Liverpool epidemic strain of P. aeruginosa. PMID:27536294

  13. Divergence of a strain of Pseudomonas aeruginosa during an outbreak of ovine mastitis.

    PubMed

    Wright, Elli A; Di Lorenzo, Valeria; Trappetti, Claudia; Liciardi, Manuele; Orru, Germano; Viti, Carlo; Bronowski, Christina; Hall, Amanda J; Darby, Alistair C; Oggioni, Marco R; Winstanley, Craig

    2015-01-30

    Bacterial infections causing mastitis in sheep can result in severe economic losses for farmers. A large survey of milk samples from ewes with mastitis in Sardinia, Italy, indicated an increasing prevalence of Pseudomonas aeruginosa infections. It has been shown previously that during chronic, biofilm-associated infections P. aeruginosa populations diversify. We report the phenotypic and genomic characterisation of two clonal P. aeruginosa isolates (PSE305 and PSE306) from a mastitis infection outbreak, representing distinct colony morphology variants. In addition to pigment production, PSE305 and PSE306 differed in phenotypic characteristics including biofilm formation, utilisation of various carbon and nitrogen sources, twitching motility. We found higher levels of expression of genes associated with biofilm formation (pelB) and twitching motility (flgD) in PSE305, compared to the biofilm and twitching-defective PSE306. Comparative genomics analysis revealed single nucleotide polymorphisms (SNPs) and minor insertion/deletion variations between PSE305 and PSE306, including a SNP mutation in the pilP gene of PSE306. By introducing a wild-type pilP gene we were able to partially complement the defective twitching motility of PSE306. There were also three larger regions of difference between the two genomes, indicating genomic instability. Hence, we have demonstrated that P. aeruginosa population divergence can occur during an outbreak of mastitis, leading to significant variations in phenotype and genotype, and resembling the behaviour of P. aeruginosa during chronic biofilm-associated infections.

  14. Effectiveness of Antipseudomonal Antibiotics and Mechanisms of Multidrug Resistance in Pseudomonas aeruginosa.

    PubMed

    El ZOWALATYl, Mohamed E; Gyetvaii, Bpla

    2016-01-01

    Pseudomonas aeruginosa is a leading human pathogen that causes serious infections at various tissues and organs leading to life threatening health problems and possible deadly outcomes. Resistance patterns vary widely whether it is from hospitals or community acquired infections. Reporting resistance profiles to a certain antibiotics provide valuable information in a given setting, but may be extrapolated outside the sampling location. In the present study, P. aeruginosa isolates were screened to determine their susceptibilities against anti-pseudomonal antimicrobial agents and possible existing mechanisms of resistance were determined. Eighty-six isolates of P. aeruginosa were recovered. Isolates representing different resistance profiles were screened for the existence of three different resistance mechanisms including drug inactivation due to metallo-β-lactamases, drug impermeability by outer membrane proteins and drug efflux. All tested isolates showed uniform susceptibility (100%, n = 86/86) to piperacillin, meropenem, amikacin, and polymyxin B. A single isolate was found to be imipenem resistant (99%, n = 85/86). The possible mechanisms of resistance of P. aeruginosa to imipenem involve active drug efflux pumps, outer membrane impermeability as well as drug inactivating enzymes. These findings demonstrate the fundamental importance of the in vitro susceptibility testing of antibiotics prior to antipseudomonal therapy and highlight the need for a continuous antimicrobial resistance surveillance programs to monitor the changing resistance patterns so that clinicians and health care officials are updated as to the most effective therapeutic agents to combat the serious outcomes of P. aeruginosa infections.

  15. Robustness and Plasticity of Metabolic Pathway Flux among Uropathogenic Isolates of Pseudomonas aeruginosa

    PubMed Central

    Berger, Antje; Dohnt, Katrin; Tielen, Petra; Jahn, Dieter; Becker, Judith; Wittmann, Christoph

    2014-01-01

    Pseudomonas aeruginosa is a human pathogen that frequently causes urinary tract and catheter-associated urinary tract infections. Here, using 13C-metabolic flux analysis, we conducted quantitative analysis of metabolic fluxes in the model strain P. aeruginosa PAO1 and 17 clinical isolates. All P. aeruginosa strains catabolized glucose through the Entner-Doudoroff pathway with fully respiratory metabolism and no overflow. Together with other NADPH supplying reactions, this high-flux pathway provided by far more NADPH than needed for anabolism: a benefit for the pathogen to counteract oxidative stress imposed by the host. P. aeruginosa recruited the pentose phosphate pathway exclusively for biosynthesis. In contrast to glycolytic metabolism, which was conserved among all isolates, the flux through pyruvate metabolism, the tricarboxylic acid cycle, and the glyoxylate shunt was highly variable, likely caused by adaptive processes in individual strains during infection. This aspect of metabolism was niche-specific with respect to the corresponding flux because strains isolated from the urinary tract clustered separately from those originating from catheter-associated infections. Interestingly, most glucose-grown strains exhibited significant flux through the glyoxylate shunt. Projection into the theoretical flux space, which was computed using elementary flux-mode analysis, indicated that P. aeruginosa metabolism is optimized for efficient growth and exhibits significant potential for increasing NADPH supply to drive oxidative stress response. PMID:24709961

  16. Post-antibiotic effect of orbifloxacin against Escherichia coli and Pseudomonas aeruginosa isolates from dogs

    PubMed Central

    2012-01-01

    Orbifloxacin is a fluoroquinolone drug used widely in companion animal medicine. In this study, we firstly determined post-antibiotic effects (PAEs) and post-antibiotic sub-minimum inhibitory concentrations (MIC) effects (PA-SMEs) of orbifloxacin for two strains each of Escherichia coli and Pseudomonas aeruginosa from dogs, and these parameters were compared with those of enrofloxacin. At twice the MIC, the PAEs of orbifloxacin ranged from -0.28-0.93 h (mean, 0.29 h) for E. coli and -0.18-1.18 h (mean, 0.37 h) for P. aeruginosa. These parameters were not significantly different for E. coli and shorter for P. aeruginosa, compared to enrofloxacin (P < 0.05). Continued exposure to 0.1, 0.2, and 0.3 the MIC of orbifloxacin resulted in average PA-SMEs of 0.55, 1.11, and 2.03 h, respectively, for E. coli, and 1.04, 1.40, and 2.47 h, respectively, for P. aeruginosa. These PA-SMEs, which had no significant differences with those of enrofloxacin, were significantly longer than the corresponding PAEs (P < 0.05). These results suggest that the PA-SME of orbifloxacin for E. coli and P. aeruginosa can be meaningfully prolonged by increase of sub-MICs. PMID:22433170

  17. Influence of Melaleuca alternifolia oil nanoparticles on aspects of Pseudomonas aeruginosa biofilm.

    PubMed

    Comin, Vanessa M; Lopes, Leonardo Q S; Quatrin, Priscilla M; de Souza, Márcia E; Bonez, Pauline C; Pintos, Francieli G; Raffin, Renata P; Vaucher, Rodrigo de A; Martinez, Diego S T; Santos, Roberto C V

    2016-04-01

    The Pseudomonas aeruginosa is a gram-negative bacillus and frequent cause of infection. This microorganism is resistant intrinsically to various drugs. The P. aeruginosa is associated with the biofilm formation, which causes worsen the prognosis and difficulty the treatment. The influence of Melaleuca alternifolia oil or "tree of tee" oil (TTO) and TTO nanoparticles on adhesion of P. aeruginosa in buccal epithelial cells was investigated. Also was determined the antimicrobial and antibiofilm activity against this microorganism. The TTO nanoparticles were produced by deposition of preformed polymer and the physic-chemical properties of nanoparticles were measured by electrophoresis and dynamic light scattering. The characterization of nanoparticle showed acceptable values for diameter and zeta potential. The evaluation of antimicrobial and antibiofilm activity against P. aeruginosa PAO1 was performed by microdilution indicating the minimal inhibitory concentration, and the potential antibiofilm. It was verified the action on virulence factors such the motility, besides the influence on adhesion in buccal epithelial cells. Both oil and nanoparticles showed a decrease in adhesion of microorganisms to buccal cells, decrease of biofilm and interfering on P. aeruginosa PAO1 motility. The nanostructuration of TTO, shows be a viable alternative against formed biofilm microorganisms. PMID:26821356

  18. Synthesis and characterization of Pseudomonas aeruginosa alginate-tetanus toxoid conjugate.

    PubMed

    Kashef, Nasim; Behzadian-Nejad, Qorban; Najar-Peerayeh, Shahin; Mousavi-Hosseini, Kamran; Moazzeni, Mohammad; Djavid, Gholamreza Esmaeeli

    2006-10-01

    Chronic infection with Pseudomonas aeruginosa is the main proven perpetrator of lung function decline and ultimate mortality in cystic fibrosis (CF) patients. Mucoid strains of this bacterium elaborate mucoid exopolysaccharide, also referred to as alginate. Alginate-based immunization of naïve animals elicits opsonic antibodies and leads to clearance of mucoid P. aeruginosa from the lungs. Alginate was isolated from mucoid P. aeruginosa strain 8821M by repeated ethanol precipitation, dialysis, proteinase and nuclease digestion, and chromatography. To improve immunogenicity, the purified antigen was coupled to tetanus toxoid (TT) with adipic acid dihydrazide (ADH) as a spacer and 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDAC) as a linker. The reaction mixture was passed through a Sepharose CL-4B column. The resulting conjugate was composed of TT and large-size alginate polymer at a ratio of about 3 : 1; it was non-toxic and non-pyrogenic, and elicited high titres of alginate-specific IgG. Antisera raised against the conjugate had high opsonic activity against the vaccine strain. The alginate conjugate was also able to protect mice against a lethal dose of mucoid P. aeruginosa. These data indicate that an alginate-based vaccine has significant potential to protect against chronic infection with mucoid P. aeruginosa in the CF host. PMID:17005795

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

    PubMed

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

    2014-10-15

    The ability to quickly detect the presence of pathogenic bacteria in patient samples is of the outmost importance to expedient patient care. Here we report the direct, selective, and sensitive detection of the opportunistic pathogen Pseudomonas aeruginosa, spiked in human whole blood with sodium heparin, urine, sputum, and bronchial lavage samples using unmodified, disposable carbon electrode sensors that detect the presence of pyocyanin, a virulence factor that is unique to this species. Square wave voltammetry scans of biological fluids from healthy individuals spiked with P. aeruginosa showed a clear pyocyanin response within one day of culturing at 37°C. Scans of supernatants taken from cultures of P. aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermis, and Bacillus cereus taken over a span of three days in the potential range from -0.5 to 0 V vs. an Ag/AgCl reference showed no electrochemically detectable molecules with the exception of P. aeruginosa. The results indicate the potential to sensitively and selectively determine the presence of P. aeruginosa in human samples via the electrochemical detection of pyocyanin in less than 5 min, without any sample preparation or separation steps. PMID:24813917

  20. Analysis of the swimming activity of Pseudomonas aeruginosa by using photonic force microscope

    NASA Astrophysics Data System (ADS)

    Chan, Chia-Han; Chang, Bo-Jui; Huang, Ying-Jung; Fan, Chia-Chieh; Peng, Hwei-Ling; Chi, Sien; Hsu, Long

    2005-08-01

    Swimming activity of flagella is a main factor of the motility of bacteria. Flagella expressed on the surface of bacterial species serve as a primary means of motility including swimming. We propose to use optical tweezers to analyze the swimming activity of bacteria. The sample bacteria in the work is Pseudomonas aeruginosa, and it is a gram-negative bacterium and often causes leading to burn wound infections, urinary-tract infections, and pneumonia. The single polar flagellum of P. aeruginosa has been demonstrated to be important virulence and colonization factor of this opportunistic pathogen. We demonstrate a gene to regulate the bacterial swimming activity in P. aeruginosa PAO1 by biological method. However, the change of flagellar morphology was not observed by electron microscopy analysis, suggesting that the gene regulates the flagellar rotation that could not be detected by biological method. PFM exhibits a spatial resolution of a few nanometers to detect the relative position of the probe at an acquisition rate over 1 MHz. By binding a probe such as a bead or a quantum dot on the flagella, we expect the rotation of the probe due to the flagella could be detected. It is expected that the study of the swimming activity of P. aeruginosa provide potent method for the pathogenic role of the flagella in P. aeruginosa.

  1. Chronic Pseudomonas aeruginosa infection-induced chronic bronchitis and emphysematous changes in CCSP-deficient mice

    PubMed Central

    Matsumoto, Takemasa; Fujita, Masaki; Hirano, Ryosuke; Uchino, Junji; Tajiri, Yukari; Fukuyama, Satoru; Morimoto, Yasuo; Watanabe, Kentaro

    2016-01-01

    The club cell secretory protein (CCSP) is a regulator of lung inflammation following acute respiratory infection or lung injury. Recently, the relationship between CCSP and COPD has been reported. Since COPD results from an abnormal inflammatory response, we hypothesized that CCSP could have a protective role against chronic inflammation-induced lung damage. To address this issue, the pathophysiology of chronic lung inflammation induced by Pseudomonas aeruginosa in CCSP-deficient mice was determined. A tube of 5 mm in length was soaked in a fluid containing P. aeruginosa (PAO01 strain) for 1 week and inserted into the trachea of CCSP-deficient mice. One week later, P. aeruginosa was administered into the trachea. Five weeks after insertion of tube, the mice were sacrificed. Bronchoalveolar lavage fluids were collected to determine the bacterial growth, and the lung histology and physiology were also examined. P. aeruginosa was continuously detected in bronchoalveolar lavage fluids during the study. Neutrophils were increased in the bronchoalveolar lavage fluids from the CCSP-deficient mice in comparison to wild-type mice. A histological study demonstrated chronic inflammation around bronchus, serious bronchial stenosis, and alveolar enlargement in the CCSP-deficient mice. The lung physiology study demonstrated an increase in the lung compliance of the CCSP-deficient mice. Chronic P. aeruginosa inflammation resulted in chronic bronchitis and emphysematous changes in the CCSP-deficient mice. CCSP could play an important role in protecting the host from the chronic inflammation-induced lung damage. PMID:27703342

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

    PubMed

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

    2015-01-01

    The Gram-negative bacterium Pseudomonas aeruginosa represents a prototype of multi-drug resistant opportunistic pathogens for which novel therapeutic options are urgently required. In order to identify new candidates as potential drug targets, we combined large-scale transposon mutagenesis data analysis and bioinformatics predictions to retrieve a set of putative essential genes which are conserved in P. aeruginosa and predicted to encode cell envelope or secreted proteins. By generating unmarked deletion or conditional mutants, we confirmed the in vitro essentiality of two periplasmic proteins, LptH and LolA, responsible for lipopolysaccharide and lipoproteins transport to the outer membrane respectively, and confirmed that they are important for cell envelope stability. LptH was also found to be essential for P. aeruginosa ability to cause infection in different animal models. Conversely, LolA-depleted cells appeared only partially impaired in pathogenicity, indicating that this protein likely plays a less relevant role during bacterial infection. Finally, we ruled out any involvement of the other six proteins under investigation in P. aeruginosa growth, cell envelope stability and virulence. Besides proposing LptH as a very promising drug target in P. aeruginosa, this study confirms the importance of in vitro and in vivo validation of potential essential genes identified through random transposon mutagenesis.

  3. Antimicrobial susceptibility differences among mucoid and non-mucoid Pseudomonas aeruginosa isolates

    PubMed Central

    Owlia, Parviz; Nosrati, Rahim; Alaghehbandan, Reza; Lari, Abdolaziz Rastegar

    2014-01-01

    Pseudomonas aeruginosa is one of the most important opportunistic bacteria, causing a wide variety of infections particularly in immunocompromised patients. The extracellular glycocalyx is produced in copious amounts by mucoid strains of P. aeruginosa. Mucoid and non-mucoid P. aeruginosa strains show some differences in their antimicrobial susceptibility pattern. The aim of this study was to investigate the frequency of mucoid and non-mucoid types and their antimicrobial susceptibility patterns isolated from Milad and Mostafa Khomeini Hospital in Tehran, Iran. One hundred P. aeruginosa isolates were collected which all were confirmed by conventional biochemical tests and PCR assay using specific primers for oprI and oprL lipoproteins. Mucoid and non-mucoid types of isolates were determined by culturing isolates on BHI agar containing Congo red and Muir mordant staining method. The susceptibility pattern of isolates against 23 different antibiotics was assessed using MIC sensititre susceptibility plates. Fifty of 100 of isolates were mucoid type, of which 14 isolates were from Mostafa Khomeini Hospital. Frequency of mucoid type of P. aeruginosa in Mostafa Khomeini hospital (70%) was higher than that seen in Milad hospital (45%). The statistical analysis of MICs results showed significant differences in antimicrobial resistance among mucoid and non-mucoid types (non mucoid strains showed more resistance against tested antibiotics). This may be due to the tendency of some antibiotics to attach to extracellular glycocalyx of mucoid strains. PMID:25152858

  4. Antimicrobial susceptibility differences among mucoid and non-mucoid Pseudomonas aeruginosa isolates.

    PubMed

    Owlia, Parviz; Nosrati, Rahim; Alaghehbandan, Reza; Lari, Abdolaziz Rastegar

    2014-01-01

    Pseudomonas aeruginosa is one of the most important opportunistic bacteria, causing a wide variety of infections particularly in immunocompromised patients. The extracellular glycocalyx is produced in copious amounts by mucoid strains of P. aeruginosa. Mucoid and non-mucoid P. aeruginosa strains show some differences in their antimicrobial susceptibility pattern. The aim of this study was to investigate the frequency of mucoid and non-mucoid types and their antimicrobial susceptibility patterns isolated from Milad and Mostafa Khomeini Hospital in Tehran, Iran. One hundred P. aeruginosa isolates were collected which all were confirmed by conventional biochemical tests and PCR assay using specific primers for oprI and oprL lipoproteins. Mucoid and non-mucoid types of isolates were determined by culturing isolates on BHI agar containing Congo red and Muir mordant staining method. The susceptibility pattern of isolates against 23 different antibiotics was assessed using MIC sensititre susceptibility plates. Fifty of 100 of isolates were mucoid type, of which 14 isolates were from Mostafa Khomeini Hospital. Frequency of mucoid type of P. aeruginosa in Mostafa Khomeini hospital (70%) was higher than that seen in Milad hospital (45%). The statistical analysis of MICs results showed significant differences in antimicrobial resistance among mucoid and non-mucoid types (non mucoid strains showed more resistance against tested antibiotics). This may be due to the tendency of some antibiotics to attach to extracellular glycocalyx of mucoid strains. PMID:25152858

  5. Disinfection of Escherichia coli and Pseudomonas aeruginosa by copper in water.

    PubMed

    Armstrong, Andrew M; Sobsey, Mark D; Casanova, Lisa M

    2016-06-01

    When households lack access to continuous piped water, water storage in the home creates opportunities for contamination. Storage in copper vessels has been shown to reduce microbes, but inactivation kinetics of enteric bacteria in water by copper alone needs to be understood. This work characterized inactivation kinetics of Escherichia coli and Pseudomonas aeruginosa by dissolved ionic copper in water. Reductions of E. coli and P. aeruginosa increase with increasing dose. At 0.3 mg/L, there was a 2.5 log10 reduction of E. coli within 6 hours. At 1 and 3 mg/L, the detection limit was reached between 3 and 6 hours; maximum reduction measured was 8.5 log10. For P. aeruginosa, at 6 hours there was 1 log10 reduction at 0.3 mg/L, 3.0 log10 at 1 mg/L, and 3.6 log10 at 3 mg/L. There was no significant decline in copper concentration. Copper inactivates bacteria under controlled conditions at doses between 0.3 and 1 mg/L. E. coli was inactivated more rapidly than P. aeruginosa. Copper at 1 mg/L can achieve 99.9% inactivation of P. aeruginosa and 99.9999997% inactivation of E. coli over 6 hours, making it a candidate treatment for stored household water.

  6. Prevalence and Antimicrobial-Resistance of Pseudomonas aeruginosa in Swimming Pools and Hot Tubs

    PubMed Central

    Lutz, Jonathan K.; Lee, Jiyoung

    2011-01-01

    Pseudomonas aeruginosa is an important opportunistic pathogen in recreational waters and the primary cause of hot tub folliculitis and otitis externa. The aim of this surveillance study was to determine the background prevalence and antimicrobial resistance profile of P. aeruginosa in swimming pools and hot tubs. A convenience sample of 108 samples was obtained from three hot tubs and eight indoor swimming pools. Water and swab samples were processed using membrane filtration, followed by confirmation with polymerase chain reaction. Twenty-three samples (21%) were positive for P. aeruginosa, and 23 isolates underwent susceptibility testing using the microdilution method. Resistance was noted to several antibiotic agents, including amikacin (intermediate), aztreonam, ceftriaxone, gentamicin, imipenem, meropenem (intermediate), ticarcillin/clavulanic acid, tobramycin (intermediate), and trimethoprim/sulfamethoxazole. The results of this surveillance study indicate that 96% of P. aeruginosa isolates tested from swimming pools and hot tubs were multidrug resistant. These results may have important implications for cystic fibrosis patients and other immune-suppressed individuals, for whom infection with multidrug-resistant P. aeruginosa would have greater impact. Our results underlie the importance of rigorous facility maintenance, and provide prevalence data on the occurrence of antimicrobial resistant strains of this important recreational water-associated and nosocomial pathogen. PMID:21556203

  7. The ferrichrome receptor A as a new target for Pseudomonas aeruginosa virulence attenuation.

    PubMed

    Lee, Keehoon; Lee, Kang-Mu; Go, Junhyeok; Ryu, Jae-Chan; Ryu, Ji-Hwan; Yoon, Sang Sun

    2016-06-01

    Pseudomonas aeruginosa is an opportunistic pathogen, known to develop robust biofilms. Its biofilm development increases when antibiotics are presented at subminimal inhibitory concentrations (MICs) for reasons that remain unclear. In order to identify genes that affect biofilm development under such a sublethal antibiotic stress condition, we screened a transposon (Tn) mutant library of PAO1, a prototype P. aeruginosa strain. Among ∼5000 mutants, a fiuA gene mutant was verified to form very defective biofilms in the presence of sub-MIC carbenicillin. The fiuA gene encodes ferrichrome receptor A, involved in the iron acquisition process. Of note, biofilm formation was not decreased in the ΔpchΔpvd mutant defective in the production of pyochelin and pyoverdine, two well-characterized P. aeruginosa siderophore molecules. Moreover, ΔfiuA, a non-polar fiuA deletion mutant, produced a significantly decreased level of elastase, a major virulence determinant. Mouse airway infection experiments revealed that the mutant expressed significantly less pathogenicity. Our results suggest that the fiuA gene has pleiotropic functions that affect P. aeruginosa biofilm development and virulence. The targeting of FiuA could enable the attenuation of P. aeruginosa virulence and may be suitable for the development of a drug that specifically controls the virulence of this important pathogen. PMID:27190289

  8. Pigments influence the tolerance of Pseudomonas aeruginosa PAO1 to photodynamically induced oxidative stress.

    PubMed

    Orlandi, Viviana T; Bolognese, Fabrizio; Chiodaroli, Luca; Tolker-Nielsen, Tim; Barbieri, Paola

    2015-12-01

    Pseudomonas aeruginosa is an opportunistic pathogen known to be resistant to different classes of antibiotics and disinfectants. P. aeruginosa also displays a certain degree of tolerance to photodynamic therapy (PDT), an alternative antimicrobial approach exploiting a photo-oxidative stress induced by exogenous photosensitizers and visible light. To evaluate whether P. aeruginosa pigments can contribute to its relative tolerance to PDT, we analysed the response to this treatment of isogenic transposon mutants of P. aeruginosa PAO1 with altered pigmentation. In general, in the presence of pigments a higher tolerance to PDT-induced photo-oxidative stress was observed. Hyperproduction of pyomelanin makes the cells much more tolerant to stress caused by either radicals or singlet oxygen generated by different photosensitizers upon photoactivation. Phenazines, pyocyanin and phenazine-1-carboxylic acid, produced in different amounts depending on the cultural conditions, are able to counteract both types of PDT-elicited reactive oxygen species. Hyperproduction of pyoverdine, caused by a mutation in a quorum-sensing gene, rendered P. aeruginosa more tolerant to a photosensitizer that generates mainly singlet oxygen, although in this case the observed tolerance to photo-oxidative stress cannot be exclusively attributed to the presence of the pigment. PMID:26419906

  9. Modulation of antibiotic resistance in Pseudomonas aeruginosa by ZnO nanoparticles

    PubMed Central

    Bayroodi, Elnaz; Jalal, Razieh

    2016-01-01

    Background and Objectives: Bacterial resistance to conventional antibiotics has become a widespread public health problem. The aim of this study was to investigate the influence of zinc oxide nanoparticles (ZnO NPs) on the antibacterial activity of several conventional antibiotics against Pseudomonas aeruginosa. Materials and Methods: ZnO NPs were prepared by solvothermal method and dispersed in glycerol with the help of ammonium citrate as a dispersant. The antibacterial effects of the resulting ZnO nanofluid, ceftazidime, tobramycin, and ciprofloxacin were investigated against two P. aeruginosa strains, including one clinical isolate and P. aeruginosa ATCC 9027 using microdilution method. For the evaluation of the combined effect of ZnO nanofluid and antibiotics, the fractional inhibitory concentration indices were calculated and isobolograms were plotted. Results: Clinical strain in comparison to standard strain of P. aeruginosa showed more resistance to ZnO nanofluid and the antibiotics. ZnO nanofluid acted synergistically with ceftazidime and tobramycin against both strains. Combination of ZnO nanofluid and ciprofloxacin displayed synergistic and partial synergistic activity against clinical and standard strains of P. aeruginosa, respectively. Conclusion: The results suggest that bacterial resistance to antimicrobials could be reduced by the synergistic action of ZnO NPs. PMID:27307973

  10. Metabolite transfer with the fermentation product 2,3-butanediol enhances virulence by Pseudomonas aeruginosa

    PubMed Central

    Venkataraman, Arvind; Rosenbaum, Miriam A; Werner, Jeffrey J; Winans, Stephen C; Angenent, Largus T

    2014-01-01

    The respiratory tract of cystic fibrosis (CF) patients harbor persistent microbial communities (CF airway microbiome) with Pseudomonas aeruginosa emerging as a dominant pathogen. Within a polymicrobial infection, interactions between co-habitant microbes can be important for pathogenesis, but even when considered, these interactions are not well understood. Here, we show with in vitro experiments that, compared with glucose, common fermentation products from co-habitant bacteria significantly increase virulence factor production, antimicrobial activity and biofilm formation of P. aeruginosa. The maximum stimulating effect was produced with the fermentation product 2,3-butanediol, which is a substrate for P. aeruginosa, resulting in a metabolic relationship between fermenters and this pathogen. The global transcription regulator LasI LasR, which controls quorum sensing, was upregulated threefold with 2,3-butanediol, resulting in higher phenazine and exotoxin concentrations and improved biofilm formation. This indicates that the success of P. aeruginosa in CF airway microbiomes could be governed by the location within the food web with fermenting bacteria. Our findings suggest that interbacterial metabolite transfer in polymicrobial infections stimulates virulence of P. aeruginosa and could have a considerable impact on disease progression. PMID:24401856

  11. Inhibition and dispersal of Agrobacterium tumefaciens biofilms by a small diffusible Pseudomonas aeruginosa exoproduct(s)

    PubMed Central

    Hibbing, Michael E.; Fuqua, Clay

    2013-01-01

    Environmental biofilms often contain mixed populations of different species. In these dense communities, competition between biofilm residents for limited nutrients such as iron, can be fierce, leading to the evolution of competitive factors that affect the ability of competitors to grow or form biofilms. We have discovered a compound(s) present in the conditioned culture fluids of Pseudomonas aeruginosa that disperses and inhibits the formation of biofilms produced by the facultative plant pathogen Agrobacterium tumefaciens. The inhibitory activity is strongly induced when P. aeruginosa is cultivated in iron-limited conditions, but it does not function through iron sequestration. In addition, the production of the inhibitory activity is not regulated by the global iron regulatory protein Fur, the iron-responsive extra-cytoplasmic function (ECF) σ factor PvdS, or three of the recognized P. aeruginosa quorum sensing systems. In addition, the compound(s) responsible for the inhibition and dispersal of A. tumefaciens biofilm formation is likely distinct from the recently identified P. aeruginosa dispersal factor, cis-2-decenoic acid (CDA), as dialysis of the culture fluids showed that the inhibitory compound was larger than CDA and culture fluids that dispersed and inhibited biofilm formation by A. tumefaciens had no effect on biofilm formation by P. aeruginosa. PMID:22105093

  12. Mimicking the host and its microenvironment in vitro for studying mucosal infections by Pseudomonas aeruginosa

    PubMed Central

    Crabbé, Aurélie; Ledesma, Maria A.; Nickerson, Cheryl A.

    2014-01-01

    Why is a healthy person protected from Pseudomonas aeruginosa infections, while individuals with cystic fibrosis or damaged epithelium are particularly susceptible to this opportunistic pathogen? In order to address this question, it is essential to thoroughly understand the dynamic interplay between the host microenvironment and P. aeruginosa. Therefore, using modeI systems that represent key aspects of human mucosal tissues in health and disease allows recreating in vivo host-pathogen interactions in a physiologically relevant manner. In this review, we discuss how factors of mucosal tissues, such as apical-basolateral polarity, junctional complexes, extracellular matrix proteins, mucus, multicellular complexity (including indigenous microbiota), and other physicochemical factors affect P. aeruginosa pathogenesis and are thus important to mimic in vitro. We highlight in vitro cell and tissue culture model systems of increasing complexity that have been used over the past 35 years to study the infectious disease process of P. aeruginosa, mainly focusing on lung models, and their respective advantages and limitations. Continued improvements of in vitro models based on our expanding knowledge of host microenvironmental factors that participate in P. aeruginosa pathogenesis will help advance fundamental understanding of pathogenic mechanisms and increase the translational potential of research findings from bench to the patient’s bedside. PMID:24737619

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

    PubMed

    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

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

    PubMed Central

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

    2015-01-01

    The Gram-negative bacterium Pseudomonas aeruginosa represents a prototype of multi-drug resistant opportunistic pathogens for which novel therapeutic options are urgently required. In order to identify new candidates as potential drug targets, we combined large-scale transposon mutagenesis data analysis and bioinformatics predictions to retrieve a set of putative essential genes which are conserved in P. aeruginosa and predicted to encode cell envelope or secreted proteins. By generating unmarked deletion or conditional mutants, we confirmed the in vitro essentiality of two periplasmic proteins, LptH and LolA, responsible for lipopolysaccharide and lipoproteins transport to the outer membrane respectively, and confirmed that they are important for cell envelope stability. LptH was also found to be essential for P. aeruginosa ability to cause infection in different animal models. Conversely, LolA-depleted cells appeared only partially impaired in pathogenicity, indicating that this protein likely plays a less relevant role during bacterial infection. Finally, we ruled out any involvement of the other six proteins under investigation in P. aeruginosa growth, cell envelope stability and virulence. Besides proposing LptH as a very promising drug target in P. aeruginosa, this study confirms the importance of in vitro and in vivo validation of potential essential genes identified through random transposon mutagenesis. PMID:26621210

  15. A network biology approach to denitrification in Pseudomonas aeruginosa

    SciTech Connect

    Arat, Seda; Bullerjahn, George S.; Laubenbacher, Reinhard

    2015-02-23

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

  16. Disinfection of Escherichia coli and Pseudomonas aeruginosa by copper in water.

    PubMed

    Armstrong, Andrew M; Sobsey, Mark D; Casanova, Lisa M

    2016-06-01

    When households lack access to continuous piped water, water storage in the home creates opportunities for contamination. Storage in copper vessels has been shown to reduce microbes, but inactivation kinetics of enteric bacteria in water by copper alone needs to be understood. This work characterized inactivation kinetics of Escherichia coli and Pseudomonas aeruginosa by dissolved ionic copper in water. Reductions of E. coli and P. aeruginosa increase with increasing dose. At 0.3 mg/L, there was a 2.5 log10 reduction of E. coli within 6 hours. At 1 and 3 mg/L, the detection limit was reached between 3 and 6 hours; maximum reduction measured was 8.5 log10. For P. aeruginosa, at 6 hours there was 1 log10 reduction at 0.3 mg/L, 3.0 log10 at 1 mg/L, and 3.6 log10 at 3 mg/L. There was no significant decline in copper concentration. Copper inactivates bacteria under controlled conditions at doses between 0.3 and 1 mg/L. E. coli was inactivated more rapidly than P. aeruginosa. Copper at 1 mg/L can achieve 99.9% inactivation of P. aeruginosa and 99.9999997% inactivation of E. coli over 6 hours, making it a candidate treatment for stored household water. PMID:27280608

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

    PubMed

    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.

  18. Complete genome sequence of Pseudomonas aeruginosa lytic bacteriophage PA1O which resembles temperate bacteriophage D3112.

    PubMed

    Kim, Shukho; Rahman, Marzia; Kim, Jungmin

    2012-03-01

    A novel Pseudomonas aeruginosa lytic bacteriophage (phage), PA1Ø, was isolated, and its genome was sequenced completely. This phage is able to lyse not only P. aeruginosa but also Staphylococcus aureus. Genome analysis of PA1Ø showed that it is similar to a P. aeruginosa temperate phage, D3112, with the exception of the absence of a c repressor-encoding gene, which is known to play a critical role in the maintenance of the lysogenic state of D3112 in P. aeruginosa. PMID:22354942

  19. Pyoverdine and Proteases Affect the Response of Pseudomonas aeruginosa to Gallium in Human Serum

    PubMed Central

    Bonchi, Carlo; Frangipani, Emanuela; Imperi, Francesco

    2015-01-01

    Gallium is an iron mimetic which has recently been repurposed as an antibacterial agent due to its capability to disrupt bacterial iron metabolism. In this study, the antibacterial activity of gallium nitrate [Ga(NO3)3] was investigated in complement-free human serum (HS) on 55 Pseudomonas aeruginosa clinical isolates from cystic fibrosis and non-cystic fibrosis patients. The susceptibility of P. aeruginosa to Ga(NO3)3 in HS was dependent on the bacterial ability to acquire iron from serum binding proteins (i.e., transferrin). The extent of serum protein degradation correlated well with P. aeruginosa growth in HS, while pyoverdine production did not. However, pyoverdine-deficient P. aeruginosa strains were unable to grow in HS and overcome iron restriction, albeit capable of releasing proteases. Predigestion of HS with proteinase K promoted the growth of all strains, irrespective of their ability to produce proteases and/or pyoverdine. The MICs of Ga(NO3)3 were higher in HS than in an iron-poor Casamino Acids medium, where proteolysis does not affect iron availability. Coherently, strains displaying high proteolytic activity were less susceptible to Ga(NO3)3 in HS. Our data support a model in which both pyoverdine and proteases affect the response of P. aeruginosa to Ga(NO3)3 in HS. The relatively high Ga(NO3)3 concentration required to inhibit the growth of highly proteolytic P. aeruginosa isolates in HS poses a limitation to the potential of Ga(NO3)3 in the treatment of P. aeruginosa bloodstream infections. PMID:26149986

  20. Pseudomonas aeruginosa clinical and environmental isolates constitute a single population with high phenotypic diversity

    PubMed Central

    2014-01-01

    Background Pseudomonas aeruginosa is an opportunistic pathogen with a high incidence of hospital infections that represents a threat to immune compromised patients. Genomic studies have shown that, in contrast to other pathogenic bacteria, clinical and environmental isolates do not show particular genomic differences. In addition, genetic variability of all the P. aeruginosa strains whose genomes have been sequenced is extremely low. This low genomic variability might be explained if clinical strains constitute a subpopulation of this bacterial species present in environments that are close to human populations, which preferentially produce virulence associated traits. Results In this work, we sequenced the genomes and performed phenotypic descriptions for four non-human P. aeruginosa isolates collected from a plant, the ocean, a water-spring, and from dolphin stomach. We show that the four strains are phenotypically diverse and that this is not reflected in genomic variability, since their genomes are almost identical. Furthermore, we performed a detailed comparative genomic analysis of the four strains studied in this work with the thirteen previously reported P. aeruginosa genomes by means of describing their core and pan-genomes. Conclusions Contrary to what has been described for other bacteria we have found that the P. aeruginosa core genome is constituted by a high proportion of genes and that its pan-genome is thus relatively small. Considering the high degree of genomic conservation between isolates of P. aeruginosa from diverse environments, including human tissues, some implications for the treatment of infections are discussed. This work also represents a methodological contribution for the genomic study of P. aeruginosa, since we provide a database of the comparison of all the proteins encoded by the seventeen strains analyzed. PMID:24773920

  1. Interaction between extracellular lipase LipA and the polysaccharide alginate of Pseudomonas aeruginosa

    PubMed Central

    2013-01-01

    Background As an opportunistic human pathogen Pseudomonas aeruginosa is able to cause acute and chronic infections. The biofilm mode of life significantly contributes to the growth and persistence of P. aeruginosa during an infection process and mediates the pathogenicity of the bacterium. Within a biofilm mucoid strains of P. aeruginosa simultaneously produce and secrete several hydrolytic enzymes and the extracellular polysaccharide alginate. The focus of the current study was the interaction between extracellular lipase LipA and alginate, which may be physiologically relevant in biofilms of mucoid P. aeruginosa. Results Fluorescence microscopy of mucoid P. aeruginosa biofilms were performed using fluorogenic lipase substrates. It showed a localization of the extracellular enzyme near the cells. A microtiter plate-based binding assay revealed that the polyanion alginate is able to bind LipA. A molecular modeling approach showed that this binding is structurally based on electrostatic interactions between negatively charged residues of alginate and positively charged amino acids of the protein localized opposite of the catalytic centre. Moreover, we showed that the presence of alginate protected the lipase activity by protection from heat inactivation and from degradation by the endogenous, extracellular protease elastase LasB. This effect was influenced by the chemical properties of the alginate molecules and was enhanced by the presence of O-acetyl groups in the alginate chain. Conclusion We demonstrate that the extracellular lipase LipA from P. aeruginosa interacts with the polysaccharide alginate in the self-produced extracellular biofilm matrix of P. aeruginosa via electrostatic interactions suggesting a role of this interaction for enzyme immobilization and accumulation within biofilms. This represents a physiological advantage for the cells. Especially in the biofilm lifestyle, the enzyme is retained near the cell surface, with the catalytic centre exposed

  2. Pseudomonas aeruginosa Syntrophy in Chronically Colonized Airways of Cystic Fibrosis Patients

    PubMed Central

    Zerr, Danielle M.; McNutt, Michael A.; Berry, Jessica E.; Burns, Jane L.; Kapur, Raj P.

    2012-01-01

    Pseudomonas aeruginosa isolates from cystic fibrosis (CF) patients undergo remarkable phenotypic divergence over time, including loss of pigmentation, hemolysis, motility, and quorum sensing and emergence of antibiotic hypersusceptibility and/or auxotrophism. With prolonged antibiotic treatment and steady decline in lung function in chronically infected patients, the divergent characteristics associated with CF isolates have traditionally been regarded as “adapted/unusual virulence,” despite the degenerative nature of these adaptations. We examined the phenotypic and genotypic diversity in clonally related isogenic strains of P. aeruginosa from individual CF patients. Our observations support a novel model of intra-airway pseudomonal syntrophy and accompanying loss of virulence. A 2007 calendar year collection of CF P. aeruginosa isolates (n = 525) from 103 CF patients yielded in vitro MICs of sulfamethoxazole-trimethoprim (SMX-TMP, which typically has no activity against P. aeruginosa) ranging from 0.02 to >32 μg/ml (median, 1.5). Coisolation of clonally related SMX-TMP-susceptible and -resistant P. aeruginosa strains from the same host was common (57%), as were isogenic coisolates with mutations in efflux gene determinants (mexR, mexAB-oprM, and mexZ) and genes governing DNA mismatch repair (mutL and mutS). In this cohort, complete in vitro growth complementation between auxotrophic and prototrophic P. aeruginosa isogenic strains was evident and concurrent with the coding sequence mosaicism in resistance determinants. These observations suggest that syntrophic clonal strains evolve in situ in an organized colonial structure. We propose that P. aeruginosa adopts a multicellular lifestyle in CF patients due to host selection of an energetically favorable, less-virulent microbe restricted within and symbiotic with the airway over the host's lifetime. PMID:22964251

  3. Clustering of mutations affecting alginic acid biosynthesis in mucoid Pseudomonas aeruginosa.

    PubMed Central

    Darzins, A; Wang, S K; Vanags, R I; Chakrabarty, A M

    1985-01-01

    A 10-kilobase DNA fragment previously shown to contain the phosphomannose isomerase gene (pmi) of Pseudomonas aeruginosa was used to construct a pBR325-based hybrid that can be propagated in P. aeruginosa only by the formation of a chromosomal-plasmid cointegrate. This plasmid, designated pAD4008, was inserted into the P. aeruginosa chromosome by recombination at a site of homology between the cloned P. aeruginosa DNA and the chromosome. Mobilization of pAD4008 into P. aeruginosa PAO and 8830 and selection for the stable acquisition of tetracycline resistance resulted in specific and predictable changes in the pattern of endonuclease restriction sites in the phosphomannose isomerase gene region of the chromosomes. Chromosomal DNA from the tetracycline-resistant transformants was used to clone the drug resistance determinant with Bg/II or XbaI, thereby allowing the "walking" of the P. aeruginosa chromosome in the vicinity of the pmi gene. Analysis of overlapping tetracycline-resistant clones indicated the presence of sequences homologous to the DNA insert of plasmid pAD2, a recombinant clone of P. aeruginosa origin previously shown to complement several alginate-negative mutants. Restriction mapping, subcloning, and complementation analysis of a 30-kilobase DNA region demonstrated the tight clustering of several genetic loci involved in alginate biosynthesis. Furthermore, the tetracycline resistance determinant in PAO strain transformed by pAD4008 was mapped on the chromosome by plasmid FP2-mediated conjugation and was found to be located near 45 min. Images PMID:3932325

  4. The complex interplay of iron, biofilm formation, and mucoidy affecting antimicrobial resistance of Pseudomonas aeruginosa

    PubMed Central

    Oglesby-Sherrouse, Amanda G.; Djapgne, Louise; Nguyen, Angela T.; Vasil, Adriana I.; Vasil, Michael L.

    2014-01-01

    Pseudomonas aeruginosa is a Gram-negative opportunistic bacterial pathogen that is refractory to a variety of current antimicrobial therapeutic regimens. Complicating treatment of such infections is the ability of P. aeruginosa to form biofilms, as well as several innate and acquired resistance mechanisms. Previous studies suggest iron plays a role in resistance to antimicrobial therapy, including the efficacy of an FDA-approved iron chelator, deferasirox (DSX), or Gallium, an iron analog, in potentiating antibiotic-dependent killing of P. aeruginosa biofilms. Here we show that iron-replete conditions enhance resistance of P. aeruginosa nonbiofilm growth against tobramycin and tigecycline. Interestingly, the mechanism of iron-enhanced resistance to each of these antibiotics is distinct. Whereas pyoverdine-mediated iron uptake is important for optimal resistance to tigecycline, it does not enhance tobramycin resistance. In contrast, heme supplementation results in increased tobramycin resistance, while having no significant effect on tigecycline resistance. Thus, non-siderophore bound iron plays an important role in resistance to tobramycin, while pyoverdine increases the ability of P. aeruginosa to resist tigecycline treatment. Lastly, we show that iron increases the minimal concentration of tobramycin, but not tigecycline, required to eradicate P. aeruginosa biofilms. Moreover, iron depletion blocks the previous observed induction of biofilm formation by sub-inhibitory concentrations of tobramycin, suggesting iron and tobramycin signal through overlapping regulatory pathways to affect biofilm formation. These data further support the role of iron in P. aeruginosa antibiotic resistance, providing yet another compelling case for targeting iron acquisition for future antimicrobial drug development. PMID:24436170

  5. Pyoverdine and proteases affect the response of Pseudomonas aeruginosa to gallium in human serum.

    PubMed

    Bonchi, Carlo; Frangipani, Emanuela; Imperi, Francesco; Visca, Paolo

    2015-09-01

    Gallium is an iron mimetic which has recently been repurposed as an antibacterial agent due to its capability to disrupt bacterial iron metabolism. In this study, the antibacterial activity of gallium nitrate [Ga(NO3)3] was investigated in complement-free human serum (HS) on 55 Pseudomonas aeruginosa clinical isolates from cystic fibrosis and non-cystic fibrosis patients. The susceptibility of P. aeruginosa to Ga(NO3)3 in HS was dependent on the bacterial ability to acquire iron from serum binding proteins (i.e., transferrin). The extent of serum protein degradation correlated well with P. aeruginosa growth in HS, while pyoverdine production did not. However, pyoverdine-deficient P. aeruginosa strains were unable to grow in HS and overcome iron restriction, albeit capable of releasing proteases. Predigestion of HS with proteinase K promoted the growth of all strains, irrespective of their ability to produce proteases and/or pyoverdine. The MICs of Ga(NO3)3 were higher in HS than in an iron-poor Casamino Acids medium, where proteolysis does not affect iron availability. Coherently, strains displaying high proteolytic activity were less susceptible to Ga(NO3)3 in HS. Our data support a model in which both pyoverdine and proteases affect the response of P. aeruginosa to Ga(NO3)3 in HS. The relatively high Ga(NO3)3 concentration required to inhibit the growth of highly proteolytic P. aeruginosa isolates in HS poses a limitation to the potential of Ga(NO3)3 in the treatment of P. aeruginosa bloodstream infections.

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

    PubMed

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

    2013-02-01

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

  7. Drosophila melanogaster as an Animal Model for the Study of Pseudomonas aeruginosa Biofilm Infections In Vivo

    PubMed Central

    Mulcahy, Heidi; Sibley, Christopher D.; Surette, Michael G.; Lewenza, Shawn

    2011-01-01

    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. PMID:21998591

  8. The glycerol-3-phosphate permease GlpT is the only fosfomycin transporter in Pseudomonas aeruginosa.

    PubMed

    Castañeda-García, Alfredo; Rodríguez-Rojas, Alexandro; Guelfo, Javier R; Blázquez, Jesús

    2009-11-01

    Fosfomycin is transported into Escherichia coli via both glycerol-3-phosphate (GlpT) and a hexose phosphate transporter (UhpT). Consequently, the inactivation of either glpT or uhpT confers increased fosfomycin resistance in this species. The inactivation of other genes, including ptsI and cyaA, also confers significant fosfomycin resistance. It has been assumed that identical mechanisms are responsible for fosfomycin transport into Pseudomonas aeruginosa cells. The study of an ordered library of insertion mutants in P. aeruginosa PA14 demonstrated that only insertions in glpT confer significant resistance. To explore the uniqueness of this resistance target in P. aeruginosa, the linkage between fosfomycin resistance and the use of glycerol-3-phosphate was tested. Fosfomycin-resistant (Fos-R) mutants were obtained in LB and minimal medium containing glycerol as the sole carbon source at a frequency of 10(-6). However, no Fos-R mutants grew on plates containing fosfomycin and glycerol-3-phosphate instead of glycerol (mutant frequency, < or = 5 x 10(-11)). In addition, 10 out of 10 independent spontaneous Fos-R mutants, obtained on LB-fosfomycin, harbored mutations in glpT, and in all cases the sensitivity to fosfomycin was recovered upon complementation with the wild-type glpT gene. The analysis of these mutants provides additional insights into the structure-function relationship of glycerol-3-phosphate the transporter in P. aeruginosa. Studies with glucose-6-phosphate and different mutant derivatives strongly suggest that P. aeruginosa lacks a specific transport system for this sugar. Thus, glpT seems to be the only fosfomycin resistance mutational target in P. aeruginosa. The high frequency of Fos-R mutations and their apparent lack of fitness cost suggest that Fos-R variants will be obtained easily in vivo upon the fosfomycin treatment of P. aeruginosa infections.

  9. A crucial role of Flagellin in the induction of airway mucus production by Pseudomonas aeruginosa.

    PubMed

    Ben Mohamed, Fatima; Mohamed, Fatima Ben; Garcia-Verdugo, Ignacio; Medina, Mathieu; Balloy, Viviane; Chignard, Michel; Ramphal, Reuben; Touqui, Lhousseine

    2012-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen involved in nosocomial infections. Flagellin is a P. aeruginosa virulence factor involved in host response to this pathogen. We examined the role of flagellin in P. aeruginosa-induced mucus secretion. Using a mouse model of pulmonary infection we showed that PAK, a wild type strain of P. aeruginosa, induced airway mucus secretion and mucin muc5ac expression at higher levels than its flagellin-deficient mutant (ΔFliC). PAK induced expression of MUC5AC and MUC2 in both human airway epithelial NCI-H292 cell line and in primary epithelial cells. In contrast, ΔFliC infection had lower to no effect on MUC5AC and MUC2 expressions. A purified P. aeruginosa flagellin induced MUC5AC expression in parallel to IL-8 secretion in NCI-H292 cells. Accordingly, ΔFliC mutant stimulated IL-8 secretion at significantly lower levels compared to PAK. Incubation of NCI-H292 cells with exogenous IL-8 induced MUC5AC expression and pre-incubation of these cells with an anti-IL-8 antibody abrogated flagellin-mediated MUC5AC expression. Silencing of TLR5 and Naip, siRNA inhibited both flagellin-induced MUC5AC expression and IL-8 secretion. Finally, inhibition of ERK abolished the expression of both PAK- and flagellin-induced MUC5AC. We conclude that: (i) flagellin is crucial in P. aeruginosa-induced mucus hyper-secretion through TLR5 and Naip pathways; (ii) this process is mediated by ERK and amplified by IL-8. Our findings help understand the mechanisms involved in mucus secretion during pulmonary infectious disease induced by P. aeruginosa, such as in cystic fibrosis. PMID:22768318

  10. Pyoverdine and proteases affect the response of Pseudomonas aeruginosa to gallium in human serum.

    PubMed

    Bonchi, Carlo; Frangipani, Emanuela; Imperi, Francesco; Visca, Paolo

    2015-09-01

    Gallium is an iron mimetic which has recently been repurposed as an antibacterial agent due to its capability to disrupt bacterial iron metabolism. In this study, the antibacterial activity of gallium nitrate [Ga(NO3)3] was investigated in complement-free human serum (HS) on 55 Pseudomonas aeruginosa clinical isolates from cystic fibrosis and non-cystic fibrosis patients. The susceptibility of P. aeruginosa to Ga(NO3)3 in HS was dependent on the bacterial ability to acquire iron from serum binding proteins (i.e., transferrin). The extent of serum protein degradation correlated well with P. aeruginosa growth in HS, while pyoverdine production did not. However, pyoverdine-deficient P. aeruginosa strains were unable to grow in HS and overcome iron restriction, albeit capable of releasing proteases. Predigestion of HS with proteinase K promoted the growth of all strains, irrespective of their ability to produce proteases and/or pyoverdine. The MICs of Ga(NO3)3 were higher in HS than in an iron-poor Casamino Acids medium, where proteolysis does not affect iron availability. Coherently, strains displaying high proteolytic activity were less susceptible to Ga(NO3)3 in HS. Our data support a model in which both pyoverdine and proteases affect the response of P. aeruginosa to Ga(NO3)3 in HS. The relatively high Ga(NO3)3 concentration required to inhibit the growth of highly proteolytic P. aeruginosa isolates in HS poses a limitation to the potential of Ga(NO3)3 in the treatment of P. aeruginosa bloodstream infections. PMID:26149986

  11. Role of Iron Uptake Systems in Pseudomonas aeruginosa Virulence and Airway Infection.

    PubMed

    Minandri, Fabrizia; Imperi, Francesco; Frangipani, Emanuela; Bonchi, Carlo; Visaggio, Daniela; Facchini, Marcella; Pasquali, Paolo; Bragonzi, Alessandra; Visca, Paolo

    2016-08-01

    Pseudomonas aeruginosa is a leading cause of hospital-acquired pneumonia and chronic lung infections in cystic fibrosis patients. Iron is essential for bacterial growth, and P. aeruginosa expresses multiple iron uptake systems, whose role in lung infection deserves further investigation. P. aeruginosa Fe(3+) uptake systems include the pyoverdine and pyochelin siderophores and two systems for heme uptake, all of which are dependent on the TonB energy transducer. P. aeruginosa also has the FeoB transporter for Fe(2+) acquisition. To assess the roles of individual iron uptake systems in P. aeruginosa lung infection, single and double deletion mutants were generated in P. aeruginosa PAO1 and characterized in vitro, using iron-poor media and human serum, and in vivo, using a mouse model of lung infection. The iron uptake-null mutant (tonB1 feoB) and the Fe(3+) transport mutant (tonB1) did not grow aerobically under low-iron conditions and were avirulent in the mouse model. Conversely, the wild type and the feoB, hasR phuR (heme uptake), and pchD (pyochelin) mutants grew in vitro and caused 60 to 90% mortality in mice. The pyoverdine mutant (pvdA) and the siderophore-null mutant (pvdA pchD) grew aerobically in iron-poor media but not in human serum, and they caused low mortality in mice (10 to 20%). To differentiate the roles of pyoverdine in iron uptake and virulence regulation, a pvdA fpvR double mutant defective in pyoverdine production but expressing wild-type levels of pyoverdine-regulated virulence factors was generated. Deletion of fpvR in the pvdA background partially restored the lethal phenotype, indicating that pyoverdine contributes to the pathogenesis of P. aeruginosa lung infection by combining iron transport and virulence-inducing capabilities. PMID:27271740

  12. Investigating the humoral immune response in chronic venous leg ulcer patients colonised with Pseudomonas aeruginosa.

    PubMed

    Jacobsen, Jasper N; Andersen, Anders S; Sonnested, Michael K; Laursen, Inga; Jorgensen, Bo; Krogfelt, Karen A

    2011-02-01

    The ability to manage the bioburden in chronic wounds is most likely coupled to the humoral immune response of the patient. We analysed markers of systemic immune response in patients with chronic venous leg ulcers (CVLUs) colonised (no-systemic infection) with the opportunistic pathogen Pseudomonas aeruginosa. Sera from 44 clinically non infected patients with CVLUs were analysed for total IgM and IgG isotype 1-4, complement C3, mannose-binding lectin (MBL), interleukin (IL)-6, C-reactive protein (CRP) and specific anti-P. aeruginosa antibodies against exotoxin A, elastase and alkaline phosphatase. Concentrations of IL-6 versus CRP intercorrelated (β = 2.43 95% CI (1.34-4.34)), but were independent of P. aeruginosa colonisation. MBL deficiency (MBL < 500 ng/ml) correlated to high serum levels of IgG(1) (P = 0.038) consistent with a compensatory mechanism, but not related to presence of P. aeruginosa in the ulcers. Twenty-four patients (54.5%) were culture positive for P. aeruginosa, also conferring significantly high serum levels of complement C3 (P = 0.014), but only two of these had positive titres for antibodies against exotoxin A. All patient sera were negative for antibodies against elastase and alkaline phosphatase. Fluorescent in situ hybridization analysis on randomly selected culture-positive patients could not establish unambiguous presence of P. aeruginosa biofilms in the ulcers. A multiple regression model showed P. aeruginosa and systemic CRP as significant factors in deterioration of ulcer healing rate.

  13. Role of Iron Uptake Systems in Pseudomonas aeruginosa Virulence and Airway Infection.

    PubMed

    Minandri, Fabrizia; Imperi, Francesco; Frangipani, Emanuela; Bonchi, Carlo; Visaggio, Daniela; Facchini, Marcella; Pasquali, Paolo; Bragonzi, Alessandra; Visca, Paolo

    2016-08-01

    Pseudomonas aeruginosa is a leading cause of hospital-acquired pneumonia and chronic lung infections in cystic fibrosis patients. Iron is essential for bacterial growth, and P. aeruginosa expresses multiple iron uptake systems, whose role in lung infection deserves further investigation. P. aeruginosa Fe(3+) uptake systems include the pyoverdine and pyochelin siderophores and two systems for heme uptake, all of which are dependent on the TonB energy transducer. P. aeruginosa also has the FeoB transporter for Fe(2+) acquisition. To assess the roles of individual iron uptake systems in P. aeruginosa lung infection, single and double deletion mutants were generated in P. aeruginosa PAO1 and characterized in vitro, using iron-poor media and human serum, and in vivo, using a mouse model of lung infection. The iron uptake-null mutant (tonB1 feoB) and the Fe(3+) transport mutant (tonB1) did not grow aerobically under low-iron conditions and were avirulent in the mouse model. Conversely, the wild type and the feoB, hasR phuR (heme uptake), and pchD (pyochelin) mutants grew in vitro and caused 60 to 90% mortality in mice. The pyoverdine mutant (pvdA) and the siderophore-null mutant (pvdA pchD) grew aerobically in iron-poor media but not in human serum, and they caused low mortality in mice (10 to 20%). To differentiate the roles of pyoverdine in iron uptake and virulence regulation, a pvdA fpvR double mutant defective in pyoverdine production but expressing wild-type levels of pyoverdine-regulated virulence factors was generated. Deletion of fpvR in the pvdA background partially restored the lethal phenotype, indicating that pyoverdine contributes to the pathogenesis of P. aeruginosa lung infection by combining iron transport and virulence-inducing capabilities.

  14. Contribution of tap water to patient colonisation with Pseudomonas aeruginosa in a medical intensive care unit.

    PubMed

    Rogues, A-M; Boulestreau, H; Lashéras, A; Boyer, A; Gruson, D; Merle, C; Castaing, Y; Bébear, C M; Gachie, J-P

    2007-09-01

    This study examined tap water as a source of Pseudomonas aeruginosa in a medical intensive care setting. We prospectively screened specimens of patients, tap water and hands of healthcare workers (HCWs) over a six-month period in a 16-bed medical intensive care unit. Molecular relatedness of P. aeruginosa strains was investigated by pulsed-field gel electrophoresis. A total of 657 tap water samples were collected from 39 faucets and 127 hands of HCWs were sampled. P. aeruginosa was found in 11.4% of 484 tap water samples taken from patients' rooms and in 5.3% of 189 other tap water samples (P<0.01). P. aeruginosa was isolated from 38 patients. Typing of 73 non-replicate isolates (water samples, hands of HCWs and patients) revealed 32 major DNA patterns. Eleven (52.4%) of the 21 faucets were contaminated with a patient strain, found before isolation from tap water in the corresponding room in nine cases, or from the neighbouring room in two cases. Among seven P. aeruginosa strains isolated from HCW hands, the genotype obtained was the same as that from the last patient they had touched in six cases, and in the seventh with the last tap water sample used. More than half of P. aeruginosa carriage in patients was acquired via tap water or cross-transmission. Carriage of P. aeruginosa by patients was both the source and the consequence of tap water colonisation. These results emphasise the need for studies on how to control tap water contamination.

  15. Antimicrobial susceptibilities and bacteriological characteristics of bovine Pseudomonas aeruginosa and Serratia marcescens isolates from mastitis.

    PubMed

    Ohnishi, Mamoru; Sawada, Takuo; Hirose, Kazuhiko; Sato, Reiichiro; Hayashimoto, Mizuki; Hata, Eiji; Yonezawa, Chizuko; Kato, Hajime

    2011-12-29

    The presence of metallo-β-lactamase (MBL)-producing and multidrug-resistant Pseudomonas aeruginosa (MDRP) strains among bovine isolates of Gram-negative bacilli, and O-serotypes of bovine Serratia marcescens and P. aeruginosa isolates have been reported rarely. The aims of this study were to (1) elucidate antimicrobial susceptibilities and O-serotypes of P. aeruginosa and S. marcescens isolates from bovine mastitis and the presence of MBL-producers and MDRP strains among them and (2) evaluate their relationships to human isolates. We investigated the MICs of 24 antimicrobials and O-serotypes for 116 P. aeruginosa and 55 S. marcescens isolates in Japan, primarily in 2006. A total of 171 isolates exhibited high antimicrobial susceptibilities with the exception of a partial drug. P. aeruginosa isolates exhibited high susceptibilities of ≥ 95.7% to ciprofloxacin, imipenem, meropenem, piperacillin, ceftazidime, cefepime, cefoperazone/sulbactam, amikacin, tobramycin, and gentamicin; however, they exhibited a susceptibility of only 69.8% to aztreonam. They exhibited substantial resistances to ceftriaxone, enrofloxacin, cefotaxime, and moxalactam. S. marcescens isolates exhibited high susceptibilities of ≥ 90.9% to kanamycin, ceftiofur, sulfamethoxazole-trimethoprim, and the 15 aforementioned drugs, but exhibited resistance to minocycline. Neither MBL-producers nor MDRP strains were detected among the 171 strains. The dominant serotypes of P. aeruginosa isolates were OG, OA, OB, OI, OF, OE, and OK; those of S. marcescens isolates were O6 and O5. Every S. marcescens isolate was pigmented. These findings suggest that bovine P. aeruginosa and S. marcescens isolates differ from human isolates from both antibiogram and phenotypic perspectives, and could help to evaluate differences in bacteriological characteristics between bovine and human isolates.

  16. Characterization of chromosomal mediated cadmium resistance in Pseudomonas aeruginosa strain BC15.

    PubMed

    Raja, Chellaiah Edward; Selvam, Govindan Sadasivam

    2012-04-01

    Cadmium (Cd) has been used extensively in metal plating, mining, paints and plastic generation etc. In this study, Cd resistance (cadR) gene was characterized from the environmental isolate Pseudomonas aeruginosa BC15. The cadR sequences showed high homology with P. aeruginosa FLH033011 (100%), P. aeruginosa PAO1 (99%), and P. aeruginosa UCBPP-PA14 (98%) respectively. Homology modeling of cadR was carried out by using swiss-prot server. Crystal structures of E. coli CueR for Cu (1q05) and ZntR (1q08) for Zn have been used as a template. The sequence identity of P. aeruginosa cadR shares 34% for CueR and 43% for ZntR. Fold recognition of P. aeruginosa cadR was created by using PHYRE web server. Transcriptional regulator CueR (1q06a) from E. coli was chosen as the template. CadR has 31% identity and the estimated precision was 100%. The cadR gene was cloned in pET30b and transformed into E. coli BL21. The molecular weight protein of cadR was estimated to be 25 kDa by SDS-PAGE. The recombinant E. coli cadR efficiently grow in the Cd supplemented LB medium and agar plate. The order of the resistance of E. coli cadR was Mn > Pb > Cu > Cd > Ni > Zn. These findings can lead to the use of P. aeruginosa BC15 for the remediation of Cd and other heavy metals present in the polluted environment.

  17. Cellular reporter screens for inhibitors of Burkholderia pseudomallei targets in Pseudomonas aeruginosa.

    PubMed

    Moir, Donald T; Di, Ming; Moore, Richard A; Schweizer, Herbert P; Woods, Donald E

    2008-12-01

    To facilitate the discovery of new therapeutics for Burkholderia pseudomallei infections, we have developed cellular reporter screens for inhibitors of B. pseudomallei targets in the surrogate host Pseudomonas aeruginosa. Pseudomonas aeruginosa strains carrying deletions of essential genes were engineered to be dependent on the isopropyl-beta-D-thiogalactopyranoside (IPTG)-regulated expression of their B. pseudomallei orthologues on a broad-host-range plasmid. Pseudomonas aeruginosa genes which are upregulated in response to depletion of each target gene product, were fused to the Photorhabdus luminescens luxCDABE operon via pGSV3-lux-Sp(R) to generate reporter strains with increased bioluminescence upon target inhibition. A total of 11 of 19 B. pseudomallei genes complemented deletions of their orthologues in P. aeruginosa. The dependence of growth on IPTG levels varied from complete dependence (ftsQ, gyrA, glmU, secA) to slower growth in the absence of IPTG (coaD, efp, mesJ), to apparently normal growth in the absence of IPTG (ligA, lpxA, folA, ipk). Reporter screening strains have been constructed for three gene targets (gyrA, glmU, secA), and one (gyrA) has been applied to 68,000 compounds resulting in a primary hit rate of 0.5% and a confirmed hit rate of 0.06%, including several fluoroquinolones. These results provide proof of principle for surrogate cellular reporter screens as a useful approach to identify inhibitors of essential gene products. PMID:19121678

  18. Expression of Pseudomonas aeruginosa transposable phages in Pseudomonas putida cells. I. Establishment of lysogeny and lytic growth efficiency

    SciTech Connect

    Gorbunova, S.A.; Yanenko, A.S.; Akhverdyan, V.Z.; Reulets, M.A.; Krylov, V.N.

    1986-03-01

    Expression of the genomes of Pseudomonas aeruginosa transposable phages (TP) in the cells of a heterologous host, P. putida PpGl, was studied. A high efficiency of TP lytic growth in PpGl cells was obtained both after zygotic induction following RP4::TP plasmid transfer and after thermoinduction of PpGl cells lysogenic for thermoinducible prophage D3112cts15. Characteristic for PpGl cells was a high TP yield (20-25 phage D3112cts15 particles per cell), which was evidence of a high level of TP transposition in cells of this species. The frequency of RP4::TP transfer into PpGl and PA01 cells was equal, but the lysogeny detection rat was somewhat lower in PpGl. Pseudomonas aeruginosa TP can integrate into the PpGl chromosome, producing inducible lysogens. The presence of RP4 is not necessary for the expression of the TP genome in PpGl cells. The D3112cts15 TP may be used for interspecific transduction of plasmids and chromosomal markers.

  19. Cloning, expression and purification of penicillin-binding protein 3 from Pseudomonas aeruginosa CMCC 10104.

    PubMed

    An, Yan Dong; Du, Qi Zhen; Tong, Li Yan; Yu, Zhao Wu; Gong, Xing Wen

    2015-06-01

    Penicillin-binding protein 3 (PBP3) of Pseudomonas aeruginosa is the primary target of β-lactams used to treat pseudomonas infections. Meanwhile, structure change and overproduction of PBP3 play important roles in the drug resistance of P. aeruginosa. Therefore, studies on the gene and structure of PBP3 are urgently needed. P. aeruginosa CMCC 10104 is a type culture strain common used in China. However, there is no report on its genomic and proteomic profiles. In this study, based on ftsI of P. aeruginosa PAO1, the gene encoding PBP3 was cloned from CMCC 10104. A truncated version of the ftsI gene, omitting the bases encoding the hydrophobic leader peptide (amino acids 1-34), was amplified by PCR. The cloned DNA shared 99.76% identity with ftsI from PAO1. Only four bases were different (66 C-A, 1020 T-C, 1233 T-C, and 1527 T-C). However, there were no differences between their deduced amino acid sequences. The recombinant PBP3 (rPBP3), containing a 6-histidine tag, was expressed in Escherichia coli BL21 (DE3). Immobilized metal affinity chromatography (IMAC) with Ni(2+)-NTA agarose was used for its purification. The purified rPBP3 was identified by SDS-PAGE and western blot analysis, and showed a single band at about 60kDa with purity higher than 95%. The penicillin-binding assay indicated that the obtained rPBP3 was functional and not hindered by the presence of the C-terminal His-tag. The protocol described in this study offers a method for obtaining purified recombinant PBP3 from P. aeruginosa CMCC 10104.

  20. Cloning, expression and purification of penicillin-binding protein 3 from Pseudomonas aeruginosa CMCC 10104.

    PubMed

    An, Yan Dong; Du, Qi Zhen; Tong, Li Yan; Yu, Zhao Wu; Gong, Xing Wen

    2015-06-01

    Penicillin-binding protein 3 (PBP3) of Pseudomonas aeruginosa is the primary target of β-lactams used to treat pseudomonas infections. Meanwhile, structure change and overproduction of PBP3 play important roles in the drug resistance of P. aeruginosa. Therefore, studies on the gene and structure of PBP3 are urgently needed. P. aeruginosa CMCC 10104 is a type culture strain common used in China. However, there is no report on its genomic and proteomic profiles. In this study, based on ftsI of P. aeruginosa PAO1, the gene encoding PBP3 was cloned from CMCC 10104. A truncated version of the ftsI gene, omitting the bases encoding the hydrophobic leader peptide (amino acids 1-34), was amplified by PCR. The cloned DNA shared 99.76% identity with ftsI from PAO1. Only four bases were different (66 C-A, 1020 T-C, 1233 T-C, and 1527 T-C). However, there were no differences between their deduced amino acid sequences. The recombinant PBP3 (rPBP3), containing a 6-histidine tag, was expressed in Escherichia coli BL21 (DE3). Immobilized metal affinity chromatography (IMAC) with Ni(2+)-NTA agarose was used for its purification. The purified rPBP3 was identified by SDS-PAGE and western blot analysis, and showed a single band at about 60kDa with purity higher than 95%. The penicillin-binding assay indicated that the obtained rPBP3 was functional and not hindered by the presence of the C-terminal His-tag. The protocol described in this study offers a method for obtaining purified recombinant PBP3 from P. aeruginosa CMCC 10104. PMID:25514204

  1. The role of two Pseudomonas aeruginosa anthranilate synthases in tryptophan and quorum signal production

    PubMed Central

    Palmer, Gregory C.; Jorth, Peter A.

    2013-01-01

    Pseudomonas aeruginosa is a Gram-negative, opportunistic pathogen that causes infections in the lungs of individuals with the genetic disease cystic fibrosis. Density-dependent production of toxic factors regulated by the Pseudomonas quinolone signal (2-heptyl-3-hydroxy-4-quinolone; PQS) have been proposed to be involved in P. aeruginosa virulence. PQS biosynthesis requires conversion of the central metabolite chorismate to anthranilate by anthranilate synthase. This reaction is also the first step in tryptophan biosynthesis. P. aeruginosa possesses two functional anthranilate synthases, TrpEG and PhnAB, and these enzymes are not functionally redundant, as trpEG mutants are tryptophan auxotrophs but produce PQS while mutants in phnAB are tryptophan prototrophs but do not produce PQS in minimal media. The goal of the work described in this paper was to determine the mechanism for this lack of functional complementation of TrpEG and PhnAB. Our results reveal that overexpression of either enzyme compensates for tryptophan auxotrophy and PQS production in the trpEG and phnAB mutants respectively, leading to the hypothesis that differential regulation of these genes is responsible for the lack of functional complementation. In support of this hypothesis, trpEG was shown to be expressed primarily during low-density growth while phnAB was expressed primarily at high density. Furthermore, dysregulation of phnAB expression eliminated tryptophan auxotrophy in the P. aeruginosa trpEG mutant. Based on these data, we propose a model for anthranilate sequestration by differential transcriptional regulation of the two P. aeruginosa anthranilate synthase enzymes. PMID:23449919

  2. Virulence Gene Profiles of Multidrug-Resistant Pseudomonas aeruginosa Isolated From Iranian Hospital Infections

    PubMed Central

    Fazeli, Nastaran; Momtaz, Hassan

    2014-01-01

    Background: The most common hospital-acquired pathogen is Pseudomonas aeruginosa. It is a multidrug resistant bacterium causing systemic infections. Objectives: The present study was carried out in order to investigate the distribution of virulence factors and antibiotic resistance properties of Pseudomonas aeruginosa isolated from various types of hospital infections in Iran. Patients and Methods: Two-hundred and seventeen human infection specimens were collected from Baqiyatallah and Payambaran hospitals in Tehran, Iran. The clinical samples were cultured immediately and samples positive for P. aeruginosa were analyzed for the presence of antibiotic resistance and bacterial virulence genes using PCR (polymerase chain reaction). Antimicrobial susceptibility testing was performed using disk diffusion methodology with Müeller–Hinton agar. Results: Fifty-eight out of 127 (45.66%) male infection specimens and 44 out of 90 (48.88%) female infection specimens harbored P. aeruginosa. Also, 65% (in male specimens) and 21% (in female specimens) of respiratory system infections were positive for P. aeruginosa, which was a high rate. The genes encoding exoenzyme S (67.64%) and phospholipases C (45.09%) were the most common virulence genes found among the strains. The incidences of various β-lactams encoding genes, including blaTEM, blaSHV, blaOXA, blaCTX-M, blaDHA, and blaVEB were 94.11%, 16.66%, 15.68%, 18.62%, 21.56%, and 17.64%, respectively. The most commonly detected fluoroquinolones encoding gene was gyrA (15. 68%). High resistance levels to penicillin (100%), tetracycline (90.19%), streptomycin (64.70%), and erythromycin (43.13%) were observed too. Conclusions: Our findings should raise awareness about antibiotic resistance in hospitalized patients in Iran. Clinicians should exercise caution in prescribing antibiotics, especially in cases of human infections. PMID:25763199

  3. Siderophore as a potential plant growth-promoting agent produced by Pseudomonas aeruginosa JAS-25.

    PubMed

    Sulochana, M B; Jayachandra, S Y; Kumar, S Anil; Parameshwar, A B; Reddy, K Mohan; Dayanand, A

    2014-09-01

    Siderophores scavenges Fe(+3) from the vicinity of the roots of plants, and thus limit the amount of iron required for the growth of pathogens such as Fusarium oxysporum, Pythium ultimum, and Fusarium udum, which cause wilt and root rot disease in crops. The ability of Pseudomonas to grow and to produce siderophore depends upon the iron content, pH, and temperature. Maximum yield of siderophore of 130 μM was observed at pH 7.0 ± 0.2 and temperature of 30 °C at 30 h. The threshold level of iron was 50 μM, which increases up to 150 μM, favoring growth but drastically affecting the production of siderophore by Pseudomonas aeruginosa JAS-25. The seeds of agricultural crops like Cicer arietinum (chick pea), Cajanus cajan (pigeon pea), and Arachis hypogaea (ground nut) were treated with P. aeruginosa JAS-25, which enhanced the seed germination, root length, shoot length, and dry weight of chick pea, pigeon pea, and ground nut plants under pot studies. The efficient growth of the plants was not only due to the biocontrol activity of the siderophore produced by P. aeruginosa JAS-25 but also may be by the production of indole acetic acid (IAA), which influences the growth of the plants as phytohormones. PMID:25062779

  4. Conversion of the Pseudomonas aeruginosa Quinolone Signal and Related Alkylhydroxyquinolines by Rhodococcus sp. Strain BG43

    PubMed Central

    Müller, Christine; Birmes, Franziska S.; Niewerth, Heiko

    2014-01-01

    A bacterial strain, which based on the sequences of its 16S rRNA, gyrB, catA, and qsdA genes, was identified as a Rhodococcus sp. closely related to Rhodococcus erythropolis, was isolated from soil by enrichment on the Pseudomonas quinolone signal [PQS; 2-heptyl-3-hydroxy-4(1H)-quinolone], a quorum sensing signal employed by the opportunistic pathogen Pseudomonas aeruginosa. The isolate, termed Rhodococcus sp. strain BG43, cometabolically degraded PQS and its biosynthetic precursor 2-heptyl-4(1H)-quinolone (HHQ) to anthranilic acid. HHQ degradation was accompanied by transient formation of PQS, and HHQ hydroxylation by cell extracts required NADH, indicating that strain BG43 has a HHQ monooxygenase isofunctional to the biosynthetic enzyme PqsH of P. aeruginosa. The enzymes catalyzing HHQ hydroxylation and PQS degradation were inducible by PQS, suggesting a specific pathway. Remarkably, Rhodococcus sp. BG43 is also capable of transforming 2-heptyl-4-hydroxyquinoline-N-oxide to PQS. It thus converts an antibacterial secondary metabolite of P. aeruginosa to a quorum sensing signal molecule. PMID:25239889

  5. Selective biosorption of lanthanide (La, Eu, Yb) ions by Pseudomonas aeruginosa

    SciTech Connect

    Texier, A.C.; Andres, Y.; Cloirec, P. le

    1999-02-01

    The ability of Pseudomonas aeruginosa to adsorb selectively La{sup 3+}, Eu{sup 3+}, and Yb{sup 3+} from aqueous solution was investigated. The lanthanide biosorption equilibrium obeyed the Brunauer-Emmett-Teller isotherm model, indicating multilayer adsorption. Determined levels of maximum adsorption capacities were 397 {micro}mol/g for lanthanum, 290 {micro}mol/g for europium and 326 {micro}mol/g for ytterbium. The results indicated that there were about 100 preferential sites for lanthanum per g of dry biomass. Experiments with mixed-cation solutions showed that the sequence of preferential biosorption was Eu{sup 3+} = Yb{sup 3+} > La{sup 3+}. Biomass dried at 37 and 70 C showed the same selective behavior as wet biomass. Inert microbial biomass dried at 37 C appeared to be the most efficient form for experimental use. The uptake of lanthanide by P. aeruginosa cells was not affected by the presence of sodium, potassium, calcium, chloride, sulfate and nitrate ions. Aluminum was a strong inhibitor of lanthanide ions biosorption. 87% of the total Al{sup 3+} was removed from the 3 mM solution, whereas only 8%, 20% and 3% of the total La{sup 3+}, Eu{sup 3+}, and Yb{sup 3+}, respectively, were sorbed from 3 mM solutions. The results suggested that cells of Pseudomonas aeruginosa may find promising applications for removal and separation of lanthanide ions from aqueous effluents.

  6. Candida albicans and Pseudomonas aeruginosa Interaction, with Focus on the Role of Eicosanoids

    PubMed Central

    Fourie, Ruan; Ells, Ruan; Swart, Chantel W.; Sebolai, Olihile M.; Albertyn, Jacobus; Pohl, Carolina H.

    2016-01-01

    Candida albicans is commonly found in mixed infections with Pseudomonas aeruginosa, especially in the lungs of cystic fibrosis (CF) patients. Both of these opportunistic pathoge