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Sample records for acute pseudomonas aeruginosa

  1. Protective role of murine norovirus against Pseudomonas aeruginosa acute pneumonia.

    PubMed

    Thépaut, Marion; Grandjean, Teddy; Hober, Didier; Lobert, Pierre-Emmanuel; Bortolotti, Perrine; Faure, Karine; Dessein, Rodrigue; Kipnis, Eric; Guery, Benoit

    2015-01-01

    The murine norovirus (MNV) is a recently discovered mouse pathogen, representing the most common contaminant in laboratory mouse colonies. Nevertheless, the effects of MNV infection on biomedical research are still unclear. We tested the hypothesis that MNV infection could alter immune response in mice with acute lung infection. Here we report that co-infection with MNV increases survival of mice with Pseudomonas aeruginosa acute lung injury and decreases in vivo production of pro-inflammatory cytokines. Our results suggest that MNV infection can deeply modify the parameters studied in conventional models of infection and lead to false conclusions in experimental models. PMID:26338794

  2. 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.

  3. PcrV antibody protects multi-drug resistant Pseudomonas aeruginosa induced acute lung injury.

    PubMed

    Wang, Qin; Li, Huayin; Zhou, Jian; Zhong, Ming; Zhu, Duming; Feng, Nana; Liu, Fanglei; Bai, Chunxue; Song, Yuanlin

    2014-03-01

    Blocking PcrV, an essential component of the Type III secretion system (TTSS), has demonstrated efficacy against Pseudomonas aeruginosa infections. However, most of the results came from laboratory strains. Whether it is applicable to clinically isolated multi-drug resistant (MDR) strains is unknown. In this study we investigated the expression level of TTSS in clinically isolated MDR P. aeruginosa strains and the effects of anti-PcrV antibody on MDR isolate induced acute lung injury (ALI). The expression level of TTSS was quantified in 53 isolates including 25 MDR strains and 28 susceptible strains. We investigated the effect of anti-PcrV antibody through a murine model induced by instillation of a MDR strain into the left lung through trachea. Our results showed that the expression level of TTSS in MDR strains is comparable to susceptible strains. Anti-PcrV ensured the survival of challenged mice, reduced the bacteria numbers and attenuated lung inflammation and injury. This study proved that anti-PcrV may be a potentially effective strategy against MDR P. aeruginosa induced ALI. PMID:24418353

  4. Role of CD 11/CD 18 in neutrophil emigration during acute and recurrent Pseudomonas aeruginosa-induced pneumonia in rabbits.

    PubMed Central

    Kumasaka, T.; Doyle, N. A.; Quinlan, W. M.; Graham, L.; Doerschuk, C. M.

    1996-01-01

    This study examined CD11/CD18-mediated adhesion in neutrophil emigration during acute and recurrent Pseudomonas aeruginosa-induced pneumonia. Neutrophil emigration during acute pneumonia was studied in anti-CD18 antibody or murine-IgG-pretreated rabbits 4 hours after intrabronchial instillation of P. aeruginosa. To examine emigration in recurrent pneumonias, rabbits given P. aeruginosa on day 0 received anti-CD18 antibody or IgG on day 7. A second instillate was placed either at the initial site or in a separate lobe, and emigration into alveolar spaces was quantitated morphometrically after 4 hours. The results show that CD11/CD18 was required for neutrophil emigration in acute pneumonias and in recurrent pneumonias that occurred at a site distant from the initial infection. However, when the recurrent pneumonia occurred in the previously inflamed site, CD11/CD18 was not required. When the same number of organisms were instilled on days 0 and 7, emigration was reduced to 15 to 20 percent of the number that migrated initially and only CD18-independent adhesion pathways were used. Increasing the concentration of organisms threefold increased emigration through both CD18-dependent and CD18-independent pathways. These data indicate that P. aeruginosa induces CD11/CD18-dependent emigration during acute pneumonia and recurrent pneumonia at previously uninflamed sites. However, adhesion pathways are altered in regions of chronic inflammation, and a greater proportion of neutrophil emigration occurs through CD11/CD18-independent pathways. PMID:8644870

  5. The molecular mechanism of acute lung injury caused by Pseudomonas aeruginosa: from bacterial pathogenesis to host response.

    PubMed

    Sawa, Teiji

    2014-01-01

    Pseudomonas aeruginosa is the most common gram-negative pathogen causing pneumonia in immunocompromised patients. Acute lung injury induced by bacterial exoproducts is associated with a poor outcome in P. aeruginosa pneumonia. The major pathogenic toxins among the exoproducts of P. aeruginosa and the mechanism by which they cause acute lung injury have been investigated: exoenzyme S and co-regulated toxins were found to contribute to acute lung injury. P. aeruginosa secretes these toxins through the recently defined type III secretion system (TTSS), by which gram-negative bacteria directly translocate toxins into the cytosol of target eukaryotic cells. TTSS comprises the secretion apparatus (termed the injectisome), translocators, secreted toxins, and regulatory components. In the P. aeruginosa genome, a pathogenic gene cluster, the exoenzyme S regulon, encodes genes underlying the regulation, secretion, and translocation of TTSS. Four type III secretory toxins, namely ExoS, ExoT, ExoU, and ExoY, have been identified in P. aeruginosa. ExoS is a 49-kDa form of exoenzyme S, a bifunctional toxin that exerts ADP-ribosyltransferase and GTPase-activating protein (GAP) activity to disrupt endocytosis, the actin cytoskeleton, and cell proliferation. ExoT, a 53-kDa form of exoenzyme S with 75% sequence homology to ExoS, also exerts GAP activity to interfere with cell morphology and motility. ExoY is a nucleotidal cyclase that increases the intracellular levels of cyclic adenosine and guanosine monophosphates, resulting in edema formation. ExoU, which exhibits phospholipase A2 activity activated by host cell ubiquitination after translocation, is a major pathogenic cytotoxin that causes alveolar epithelial injury and macrophage necrosis. Approximately 20% of clinical isolates also secrete ExoU, a gene encoded within an insertional pathogenic gene cluster named P. aeruginosa pathogenicity island-2. The ExoU secretory phenotype is associated with a poor clinical outcome in P

  6. Chemotaxis by Pseudomonas aeruginosa.

    PubMed Central

    Moulton, R C; Montie, T C

    1979-01-01

    Chemotaxis by Pseudomonas aeruginosa RM46 has been studied, and conditions required for chemotaxis have been defined, by using the Adler capillary assay technique. Several amino acids, organic acids, and glucose were shown to be attractants of varying effectiveness for this organism. Ethylenediaminetetraacetic acid was absolutely required for chemotaxis, and magnesium was also necessary for a maximum response. Serine taxis was greatest when the chemotaxis medium contained 1.5 X 10(-5) M ethylenediaminetetraacetic acid and 0.005 M magnesium chloride. It was not necessary to include methionine in the chemotaxis medium. The strength of the chemotactic responses to glucose and to citrate was dependent on prior growth of the bacteria on glucose and citrate, respectively. Accumulation in response to serine was inhibited by the addition of succinate, citrate, malate, glucose, pyruvate, or methionine to the chemotaxis medium. Inhibition by succinate was not dependent on the concentration of attractant in the capillary. However, the degree to which glucose and citrate inhibited serine taxis was dependent on the carbon source utilized for growth. Further investigation of this inhibition may provide information about the mechanisms of chemotaxis in P. aeruginosa. PMID:104961

  7. [Macrolides, Pseudomonas aeruginosa and cystic fibrosis].

    PubMed

    Guillot, M; Amiour, M; El Hachem, C; Harchaoui, S; Ribault, V; Paris, C

    2006-10-01

    Long-term low dose azithromycin treatment in cystic fibrosis patients with chronic Pseudomonas aeruginosa infection is safe and reduces the decline in lung function, the number of acute exacerbations and improves nutritional status; underlying efficacy mechanisms are multiple and synergistic. PMID:17370396

  8. BdlA, DipA and Induced Dispersion Contribute to Acute Virulence and Chronic Persistence of Pseudomonas aeruginosa

    PubMed Central

    Li, Yi; Petrova, Olga E.; Su, Shengchang; Lau, Gee W.; Panmanee, Warunya; Na, Renuka; Hassett, Daniel J.; Davies, David G.; Sauer, Karin

    2014-01-01

    The human pathogen Pseudomonas aeruginosa is capable of causing both acute and chronic infections. Differences in virulence are attributable to the mode of growth: bacteria growing planktonically cause acute infections, while bacteria growing in matrix-enclosed aggregates known as biofilms are associated with chronic, persistent infections. While the contribution of the planktonic and biofilm modes of growth to virulence is now widely accepted, little is known about the role of dispersion in virulence, the active process by which biofilm bacteria switch back to the planktonic mode of growth. Here, we demonstrate that P. aeruginosa dispersed cells display a virulence phenotype distinct from those of planktonic and biofilm cells. While the highest activity of cytotoxic and degradative enzymes capable of breaking down polymeric matrix components was detected in supernatants of planktonic cells, the enzymatic activity of dispersed cell supernatants was similar to that of biofilm supernatants. Supernatants of non-dispersing ΔbdlA biofilms were characterized by a lack of many of the degradative activities. Expression of genes contributing to the virulence of P. aeruginosa was nearly 30-fold reduced in biofilm cells relative to planktonic cells. Gene expression analysis indicated dispersed cells, while dispersing from a biofilm and returning to the single cell lifestyle, to be distinct from both biofilm and planktonic cells, with virulence transcript levels being reduced up to 150-fold compared to planktonic cells. In contrast, virulence gene transcript levels were significantly increased in non-dispersing ΔbdlA and ΔdipA biofilms compared to wild-type planktonic cells. Despite this, bdlA and dipA inactivation, resulting in an inability to disperse in vitro, correlated with reduced pathogenicity and competitiveness in cross-phylum acute virulence models. In contrast, bdlA inactivation rendered P. aeruginosa more persistent upon chronic colonization of the murine lung

  9. Vaccination against respiratory Pseudomonas aeruginosa infection

    PubMed Central

    Grimwood, Keith; Kyd, Jennelle M; Owen, Suzzanne J; Massa, Helen M; Cripps, Allan W

    2014-01-01

    Respiratory infections caused by Pseudomonas aeruginosa are a major clinical problem globally, particularly for patients with chronic pulmonary disorders, such as those with cystic fibrosis (CF), non-CF bronchiectasis (nCFB) and severe chronic obstructive pulmonary disease (COPD). In addition, critically ill and immunocompromised patients are also at significant risk of P. aeruginosa infection. For almost half a century, research efforts have focused toward development of a vaccine against infections caused by P. aeruginosa, but a licensed vaccine is not yet available. Significant advances in identifying potential vaccine antigens have been made. Immunisations via both the mucosal and systemic routes have been trialled in animal models and their effectiveness in clearing acute infections demonstrated. The challenge for translation of this research to human applications remains, since P. aeruginosa infections in the human respiratory tract can present both as an acute or chronic infection. In addition, immunisation prior to infection may not be possible for many patients with CF, nCFB or COPD. Therefore, development of a therapeutic vaccine provides an alternative approach for treatment of chronic infection. Preliminary animal and human studies suggest that mucosal immunisation may be effective as a therapeutic vaccine against P. aeruginosa respiratory infections. Nevertheless, more research is needed to improve our understanding of the basic biology of P. aeruginosa and the mechanisms needed to upregulate the induction of host immune pathways to prevent infection. Recognition of variability in the host immune responses for a range of patient health conditions at risk from P. aeruginosa infection is also required to support development of a successful vaccine delivery strategy and vaccine. Activation of mucosal immune responses may provide improved efficacy of vaccination for P. aeruginosa during both acute exacerbations and chronic infection. PMID:25483510

  10. Capsule production by Pseudomonas aeruginosa

    SciTech Connect

    Lynn, A.R.

    1984-01-01

    Mucoid strains of Pseudomonas aeruginosa, associated almost exclusively with chronic respiratory infections in patients with cystic fibrosis, possess a capsule composed of alginic acid similar to one produced by Azotobacter vinelandii. Recent reports have provided evidence that the biosynthetic pathway for alginate in P. aeruginosa may differ from the pathway proposed for A. vinelandii in that synthesis in P. aeruginosa may occur by way of the Entner-Doudoroff pathway. Incorporation of isotope from (6-/sup 14/C)glucose into alginate by both P. aueroginosa and A. vinelandii was 10-fold greater than that from either (1-/sup 14/C)/sup -/ or (2-/sup 14/C)glucose, indicating preferential utilization of the bottom half of the glucose molecule for alginate biosynthesis. These data strongly suggest that the Entner-Doudoroff pathway plays a major role in alginate synthesis in both P. aeruginosa and A. vinelandii. The enzymes of carbohydrate metabolism in mucoid strains of P. aeruginosa appear to be unchanged whether alignate is actively produced or not and activities do not differ significantly from nonmucoid strain PAO.

  11. Pseudomonas aeruginosa infection mimicking erythema annulare centrifugum.

    PubMed

    Czechowicz, R T; Warren, L J; Moore, L; Saxon, B

    2001-02-01

    A 3-year-old girl receiving chemotherapy for acute lymphocytic leukaemia developed a rapidly expanding red annular plaque on her thigh, initially without signs of systemic toxicity or local pain. Subsequently she developed Pseudomonas aeruginosa sepsis and purpura at the leading edge of the plaque. Skin biopsy showed an extensive necrotizing vasculitis with numerous Gram-negative bacilli in the blood vessel walls. In immunocompromised individuals, skin biopsy and culture of cutaneous lesions for bacteria and fungi should be considered even in the absence of signs of systemic toxicity or multiple lesions. PMID:11233725

  12. 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. PMID:24096885

  13. Efficacy of species-specific protein antibiotics in a murine model of acute Pseudomonas aeruginosa lung infection

    PubMed Central

    McCaughey, Laura C.; Ritchie, Neil. D.; Douce, Gillian R.; Evans, Thomas J.; Walker, Daniel

    2016-01-01

    Protein antibiotics, known as bacteriocins, are widely produced by bacteria for intraspecies competition. The potency and targeted action of bacteriocins suggests that they could be developed into clinically useful antibiotics against highly drug resistant Gram-negative pathogens for which there are few therapeutic options. Here we show that Pseudomonas aeruginosa specific bacteriocins, known as pyocins, show strong efficacy in a murine model of P. aeruginosa lung infection, with the concentration of pyocin S5 required to afford protection from a lethal infection at least 100-fold lower than the most commonly used inhaled antibiotic tobramycin. Additionally, pyocins are stable in the lung, poorly immunogenic at high concentrations and efficacy is maintained in the presence of pyocin specific antibodies after repeated pyocin administration. Bacteriocin encoding genes are frequently found in microbial genomes and could therefore offer a ready supply of highly targeted and potent antibiotics active against problematic Gram-negative pathogens. PMID:27444885

  14. Pseudomonas aeruginosa Population Structure Revisited

    PubMed Central

    Pirnay, Jean-Paul; Bilocq, Florence; Pot, Bruno; Cornelis, Pierre; Zizi, Martin; Van Eldere, Johan; Deschaght, Pieter; Vaneechoutte, Mario; Jennes, Serge; Pitt, Tyrone; De Vos, Daniel

    2009-01-01

    At present there are strong indications that Pseudomonas aeruginosa exhibits an epidemic population structure; clinical isolates are indistinguishable from environmental isolates, and they do not exhibit a specific (disease) habitat selection. However, some important issues, such as the worldwide emergence of highly transmissible P. aeruginosa clones among cystic fibrosis (CF) patients and the spread and persistence of multidrug resistant (MDR) strains in hospital wards with high antibiotic pressure, remain contentious. To further investigate the population structure of P. aeruginosa, eight parameters were analyzed and combined for 328 unrelated isolates, collected over the last 125 years from 69 localities in 30 countries on five continents, from diverse clinical (human and animal) and environmental habitats. The analysed parameters were: i) O serotype, ii) Fluorescent Amplified-Fragment Length Polymorphism (FALFP) pattern, nucleotide sequences of outer membrane protein genes, iii) oprI, iv) oprL, v) oprD, vi) pyoverdine receptor gene profile (fpvA type and fpvB prevalence), and prevalence of vii) exoenzyme genes exoS and exoU and viii) group I pilin glycosyltransferase gene tfpO. These traits were combined and analysed using biological data analysis software and visualized in the form of a minimum spanning tree (MST). We revealed a network of relationships between all analyzed parameters and non-congruence between experiments. At the same time we observed several conserved clones, characterized by an almost identical data set. These observations confirm the nonclonal epidemic population structure of P. aeruginosa, a superficially clonal structure with frequent recombinations, in which occasionally highly successful epidemic clones arise. One of these clones is the renown and widespread MDR serotype O12 clone. On the other hand, we found no evidence for a widespread CF transmissible clone. All but one of the 43 analysed CF strains belonged to a ubiquitous P

  15. 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.

  16. Tryptophan Inhibits Biofilm Formation by Pseudomonas aeruginosa

    PubMed Central

    Brandenburg, Kenneth S.; Rodriguez, Karien J.; McAnulty, Jonathan F.; Murphy, Christopher J.; Abbott, Nicholas L.; Schurr, Michael J.

    2013-01-01

    Biofilm formation by Pseudomonas aeruginosa has been implicated in the pathology of chronic wounds. Both the d and l isoforms of tryptophan inhibited P. aeruginosa biofilm formation on tissue culture plates, with an equimolar ratio of d and l isoforms producing the greatest inhibitory effect. Addition of d-/l-tryptophan to existing biofilms inhibited further biofilm growth and caused partial biofilm disassembly. Tryptophan significantly increased swimming motility, which may be responsible in part for diminished biofilm formation by P. aeruginosa. PMID:23318791

  17. Correlation between cytotoxicity induced by Pseudomonas aeruginosa clinical isolates from acute infections and IL-1β secretion in a model of human THP-1 monocytes.

    PubMed

    Anantharajah, Ahalieyah; Buyck, Julien M; Faure, Emmanuel; Glupczynski, Youri; Rodriguez-Villalobos, Hector; De Vos, Daniel; Pirnay, Jean-Paul; Bilocq, Florence; Guery, Benoît; Tulkens, Paul M; Mingeot-Leclercq, Marie-Paule; Van Bambeke, Françoise

    2015-10-01

    Type III secretion system (T3SS) in Pseudomonas aeruginosa is associated with poor clinical outcome in acute infections. T3SS allows for injection of bacterial exotoxins (e.g. ExoU or ExoS) into the host cell, causing cytotoxicity. It also activates the cytosolic NLRC4 inflammasome, activating caspase-1, inducing cytotoxicity and release of mature IL-1β, which impairs bacterial clearance. In addition, flagellum-mediated motility has been suggested to also modulate inflammasome response and IL-1β release. Yet the capacity of clinical isolates to induce IL-1β release and its relation with cytotoxicity have never been investigated. Using 20 clinical isolates from acute infections with variable T3SS expression levels and human monocytes, our aim was to correlate IL-1β release with toxin expression, flagellar motility and cytotoxicity. ExoU-producing isolates caused massive cell death but minimal release of IL-1β, while those expressing T3SS but not ExoU (i.e. expressing ExoS or no toxins) induced caspase-1 activation and IL-1β release, the level of which was correlated with cytotoxicity. Both effects were prevented by a specific caspase-1 inhibitor. Flagellar motility was not correlated with cytotoxicity or IL-1β release. No apoptosis was detected. Thus, T3SS cytotoxicity is accompanied by a modification in cytokine balance for P. aeruginosa clinical isolates that do not express ExoU. PMID:26203053

  18. Transposon mutagenesis of Pseudomonas aeruginosa exoprotease genes.

    PubMed Central

    Stapleton, M J; Jagger, K S; Warren, R L

    1984-01-01

    Transposon Tn5 was used to generate protease-deficient insertion mutants of Pseudomonas aeruginosa. The presence of Tn5 in the chromosome of P. aeruginosa was demonstrated by transduction and DNA-DNA hybridization. The altered protease production and kanamycin resistance were cotransduced into a wild-type P. aeruginosa strain. A radiolabeled probe of Tn5 DNA hybridized to specific BamHI fragments isolated from the insertion mutants. Two independently isolated Tn5 insertion mutants had reduced protease production, partially impaired elastase activity, and no immunologically reactive alkaline protease. Images PMID:6317657

  19. 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

  20. Burn sepsis: bacterial interference with Pseudomonas aeruginosa.

    PubMed

    Levenson, S M; Gruber, D K; Gruber, C; Watford, A; Seifter, E

    1981-05-01

    The pathogenicity of several strains of Pseudomonas aeruginosa for burned rats (3 degrees scald burns, 20% body surface) following topical application of the bacteria to the burn within 1 hour after burning was established. Following this, it was demonstrated that purposeful infection of such 3 degrees scald burns of rats by a strain of Ps. aeruginosa of low virulence (JB-77) protects the rats from the lethal effect of subsequent (48-hour) topical contamination of the burn by a highly virulent strain of Ps. aeruginosa (VA-134) (p less than 0.001). This finding was confirmed in a similar experiment beginning with germfree rats. When the challenge with the highly virulent Ps. aeruginosa strain was 24 hours (rather than 48 hours) after the burning and topical contamination of the burn with the low virulence strain of Ps. aeruginosa, there was little protection (p N.S.). When burned rats were given the low virulence strain of Ps. aeruginosa by gavage right after burning, there was not protection to subsequent (48 hours) challenge by topical application of the highly virulent strain of Ps. aeruginosa to the burn (11/12 vs 12/12 dying). Our finding that purposeful infection of a 3 degrees burn of rats (conventional and also germfree) by a strain of Ps. aeruginosa of low virulence protects from the lethal effect of subsequent (48-hour) topical contamination of the burn by a highly virulent strain of Ps. aeruginosa is due, we believe, to direct bacterial interference between the two strains of pseudomonas. PMID:6785444

  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. Occurrence of Pseudomonas aeruginosa in Kuwait soil.

    PubMed

    Al-Saleh, Esmaeil; Akbar, Abrar

    2015-02-01

    Environmentally ubiquitous bacteria such as Pseudomonas aeruginosa evolved mechanisms to adapt and prevail under diverse conditions. In the current investigation, strains of P. aeruginosa demonstrating high rates of crude oil utilization and tolerance to high concentrations of heavy metals were found in both crude oil-contaminated and uncontaminated sites in Kuwait, and were dominant in the contaminated sites. The incidence of P. aeruginosa in tested soils implies the definitive pattern of crude oil contamination in the selection of the bacterial population in petroleum-contaminated sites in Kuwait. Surprisingly, the unculturable P. aeruginosa in different soil samples showed significant high similarity coefficients based on 16S-RFLP analyses, implying that the unculturable fraction of existing bacterial population in environmental samples is more stable and, hence, reliable for phylogenetic studies compared to the culturable bacteria. PMID:25014900

  3. 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 ...

  4. 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 ...

  5. 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

  6. Clonal complex Pseudomonas aeruginosa in horses.

    PubMed

    Kidd, Timothy J; Gibson, Justine S; Moss, Susan; Greer, Ristan M; Cobbold, Rowland N; Wright, John D; Ramsay, Kay A; Grimwood, Keith; Bell, Scott C

    2011-05-01

    Pseudomonas aeruginosa is associated with infectious endometritis in horses. Although infectious endometritis is often considered a venereal infection, there is relatively limited genotypic-based evidence to support this mode of transmission. The study sought to determine the relatedness between genital P. aeruginosa isolates collected from a limited geographical region using molecular strain typing. Enterobacterial repetitive intergenic consensus PCR typing was performed on 93 isolates collected between 2005 and 2009 from 2058 thoroughbred horses (including 18 stallions) at 66 studs. While P. aeruginosa was not detected in the stallions, 53/93 (57%) mares harbouring P. aeruginosa had clonally related strains, which included a single dominant genotype detected in 42 (45%) mares from 13 different studs. These novel findings suggest that most equine genital P. aeruginosa infections in this region may have been acquired from mechanisms other than direct horse to horse transmission. Instead, other potential acquisition pathways, as well as strain specific adaptation to the equine genital tract, should be investigated. PMID:21183294

  7. Responses of Pseudomonas aeruginosa to antimicrobials

    PubMed Central

    Morita, Yuji; Tomida, Junko; Kawamura, Yoshiaki

    2014-01-01

    Infections caused by Pseudomonas aeruginosa often are hard to treat; inappropriate chemotherapy readily selects multidrug-resistant P. aeruginosa. This organism can be exposed to a wide range of concentrations of antimicrobials during treatment; learning more about the responses of P. aeruginosa to antimicrobials is therefore important. We review here responses of the bacterium P. aeruginosa upon exposure to antimicrobials at levels below the inhibitory concentration. Carbapenems (e.g., imipenem) have been shown to induce the formation of thicker and more robust biofilms, while fluoroquinolones (e.g., ciprofloxacin) and aminoglycosides (e.g., tobramycin) have been shown to induce biofilm formation. Ciprofloxacin also has been demonstrated to enhance the frequency of mutation to carbapenem resistance. Conversely, although macrolides (e.g., azithromycin) typically are not effective against P. aeruginosa because of the pseudomonal outer-membrane impermeability and efflux, macrolides do lead to a reduction in virulence factor production. Similarly, tetracycline is not very effective against this organism, but is known to induce the type-III secretion system and consequently enhance cytotoxicity of P. aeruginosa in vivo. Of special note are the effects of antibacterials and disinfectants on pseudomonal efflux systems. Sub-inhibitory concentrations of protein synthesis inhibitors (aminoglycosides, tetracycline, chloramphenicol, etc.) induce the MexXY multidrug efflux system. This response is known to be mediated by interference with the translation of the leader peptide PA5471.1, with consequent effects on expression of the PA5471 gene product. Additionally, induction of the MexCD-OprJ multidrug efflux system is observed upon exposure to sub-inhibitory concentrations of disinfectants such as chlorhexidine and benzalkonium. This response is known to be dependent upon the AlgU stress response factor. Altogether, these biological responses of P. aeruginosa provide useful

  8. Responses of Pseudomonas aeruginosa to antimicrobials.

    PubMed

    Morita, Yuji; Tomida, Junko; Kawamura, Yoshiaki

    2014-01-01

    Infections caused by Pseudomonas aeruginosa often are hard to treat; inappropriate chemotherapy readily selects multidrug-resistant P. aeruginosa. This organism can be exposed to a wide range of concentrations of antimicrobials during treatment; learning more about the responses of P. aeruginosa to antimicrobials is therefore important. We review here responses of the bacterium P. aeruginosa upon exposure to antimicrobials at levels below the inhibitory concentration. Carbapenems (e.g., imipenem) have been shown to induce the formation of thicker and more robust biofilms, while fluoroquinolones (e.g., ciprofloxacin) and aminoglycosides (e.g., tobramycin) have been shown to induce biofilm formation. Ciprofloxacin also has been demonstrated to enhance the frequency of mutation to carbapenem resistance. Conversely, although macrolides (e.g., azithromycin) typically are not effective against P. aeruginosa because of the pseudomonal outer-membrane impermeability and efflux, macrolides do lead to a reduction in virulence factor production. Similarly, tetracycline is not very effective against this organism, but is known to induce the type-III secretion system and consequently enhance cytotoxicity of P. aeruginosa in vivo. Of special note are the effects of antibacterials and disinfectants on pseudomonal efflux systems. Sub-inhibitory concentrations of protein synthesis inhibitors (aminoglycosides, tetracycline, chloramphenicol, etc.) induce the MexXY multidrug efflux system. This response is known to be mediated by interference with the translation of the leader peptide PA5471.1, with consequent effects on expression of the PA5471 gene product. Additionally, induction of the MexCD-OprJ multidrug efflux system is observed upon exposure to sub-inhibitory concentrations of disinfectants such as chlorhexidine and benzalkonium. This response is known to be dependent upon the AlgU stress response factor. Altogether, these biological responses of P. aeruginosa provide useful

  9. Anti-PcrV antibody strategies against virulent Pseudomonas aeruginosa.

    PubMed

    Sawa, Teiji; Ito, Emi; Nguyen, Vinh Huu; Haight, Matthew

    2014-01-01

    Pseudomonas aeruginosa is an opportunistic bacterial pathogen that causes fatal acute lung infections in critically ill individuals. Its pathogenesis is associated with bacterial virulence conferred by the type III secretion system (TTSS), through which P. aeruginosa causes necrosis of the lung epithelium and disseminates into the circulation, resulting in bacteremia, sepsis, and mortality. TTSS allows P. aeruginosa to directly translocate cytotoxins into eukaryotic cells, inducing cell death. The P. aeruginosa V-antigen PcrV, a homolog of the Yersinia V-antigen LcrV, is an indispensable contributor to TTS toxin translocation. Vaccination against PcrV ensures the survival of challenged mice and decreases lung inflammation and injury. Both the rabbit polyclonal anti-PcrV antibody and the murine monoclonal anti-PcrV antibody, mAb166, inhibit TTS toxin translocation. mAb166 IgG was cloned, and a molecular engineered humanized anti-PcrV IgG antigen-binding fragment, KB001, was developed for clinical use. KB001 is currently undergoing Phase-II clinical trials for ventilator-associated pneumonia in France and chronic pneumonia in cystic fibrosis in USA. In these studies, KB001 has demonstrated its safety, a favorable pharmacokinetic profile, and promising potential as a nonantibiotic strategy to reduce airway inflammation and damage in P. aeruginosa pneumonia. PMID:25483637

  10. 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.

  11. 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

  12. Surface attachment induces Pseudomonas aeruginosa virulence

    PubMed Central

    Siryaporn, Albert; Kuchma, Sherry L.; O’Toole, George A.; Gitai, Zemer

    2014-01-01

    Pseudomonas aeruginosa infects every type of host that has been examined by deploying multiple virulence factors. Previous studies of virulence regulation have largely focused on chemical cues, but P. aeruginosa may also respond to mechanical cues. Using a rapid imaging-based virulence assay, we demonstrate that P. aeruginosa activates virulence in response to attachment to a range of chemically distinct surfaces, suggesting that this bacterial species responds to mechanical properties of its substrates. Surface-activated virulence requires quorum sensing, but activating quorum sensing does not induce virulence without surface attachment. The activation of virulence by surfaces also requires the surface-exposed protein PilY1, which has a domain homologous to a eukaryotic mechanosensor. Specific mutation of the putative PilY1 mechanosensory domain is sufficient to induce virulence in non–surface-attached cells, suggesting that PilY1 mediates surface mechanotransduction. Triggering virulence only when cells are both at high density and attached to a surface—two host-nonspecific cues—explains how P. aeruginosa precisely regulates virulence while maintaining broad host specificity. PMID:25385640

  13. Transferable imipenem resistance in Pseudomonas aeruginosa.

    PubMed Central

    Watanabe, M; Iyobe, S; Inoue, M; Mitsuhashi, S

    1991-01-01

    We isolated an imipenem-resistant strain, GN17203, of Pseudomonas aeruginosa. The strain produced a beta-lactamase that hydrolyzed imipenem. The beta-lactamase was encoded by a 31-MDa plasmid, pMS350, which belongs to incompatibility group P-9. The plasmic conferred resistance to beta-lactams, gentamicin, and sulfonamide and was transferable by conjugation to P. aeruginosa but not to Escherichia coli. The molecular weight of the purified enzyme was estimated to be 28,000, and the isoelectric point was 9.0. The enzyme showed a broad substrate profile, hydrolyzing imipenem, oxyiminocephalosporins, 7-methoxycephalosporins, and penicillins. The enzyme activity was inhibited by EDTA, iodine, p-chloromercuribenzoate, CuSO4, and HgCl2 but not by clavulanic acid or sulbactam. Images PMID:1901695

  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. 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

  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. Biosynthesis of Gold Nanoparticles Using Pseudomonas Aeruginosa

    SciTech Connect

    Abd El-Aziz, M.; Badr, Y.; Mahmoud, M. A.

    2007-02-14

    Pseudomonas aeruginosa were used for extracellular biosynthesis of gold nanoparticles (Au NPs). Consequently, Au NPs were formed due to reduction of gold ion by bacterial cell supernatant of P. aeruginos ATCC 90271, P. aeruginos (2) and P. aeruginos (1). The UV-Vis. and fluorescence spectra of the bacterial as well as chemical prepared Au NPs were recorded. Transmission electron microscopy (TEM) micrograph showed the formation of well-dispersed gold nanoparticles in the range of 15-30 nm. The process of reduction being extracellular and may lead to the development of an easy bioprocess for synthesis of Au NPs.

  18. High-resolution genotyping of Pseudomonas aeruginosa strains linked to acute post cataract surgery endophthalmitis outbreaks in India

    PubMed Central

    Kenchappa, Prashanth; Sangwan, Virender S; Ahmed, Niyaz; Rao, K Rajender; Pathengay, Avinash; Mathai, Annie; Mansoori, Tarannum; Das, Taraprasad; Hasnain, Seyed E; Sharma, Savitri

    2005-01-01

    Background Investigation of two independent outbreaks of post cataract surgery endophthalmitis identified the reservoir of epidemic strains of P. aeruginosa. Methods Patient isolates cultured from vitreous fluid of all the nine cases and from the peripheral devices of phacoemulsification machine were subjected to high-resolution Fluorescent Amplified Fragment Length Polymorphism (FAFLP) analysis. Results FAFLP based genotyping of the isolates confirmed nosocomial transmission. Although biochemical characterization and antibiotic susceptibility profiles grouped all the isolates together, FAFLP based genotyping revealed that, all the outbreak isolates were derived from 2 different strains, with independent origins. One group of isolates was traced to phacoprobe and the second one to the internal tubing system of the phacoemulsification machine used in cataract surgery. In silico analysis indicated possible evolution in both the clusters of P. aeruginosa isolates due to genetic polymorphisms. The polymorphisms were mapped to gene products (cell envelope, outer membrane proteins) possibly having significant role in pathogenesis. Conclusion The present study is probably the first one to apply FAFLP typing successfully to investigate outbreaks of postoperative endophthalmitis (POE) in an ophthalmic setting, which was able to identify the source, and helped to make rational decisions on sterilization procedures that halted more cases of infection in these hospitals. PMID:16343353

  19. OXIDATIVE ASSIMILATION OF GLUCOSE BY PSEUDOMONAS AERUGINOSA

    PubMed Central

    Duncan, Margaret G.; Campbell, J. J. R.

    1962-01-01

    Duncan, Margaret G. (The University of British Columbia, Vancouver, British Columbia, Canada) and J. J. R. Campbell. Oxidative assimilation of glucose by Pseudomonas aeruginosa. J. Bacteriol. 84:784–792. 1962—Oxidative assimilation of glucose by washed-cell suspensions of Pseudomonas aeruginosa was studied using C14-labeled substrate. At the time of glucose disappearance, only small amounts of radioactivity were present in the cells, and α-ketoglutaric acid accumulated in the supernatant fluid. Most of the material synthesized by the cells during oxidative assimilation was nitrogenous, the ammonia being supplied by the endogenous respiration. The cold trichloroacetic acid-soluble fraction and the lipid fraction appeared to be important during the early stages of oxidative assimilation, and the largest percentage of the incorporated radioactivity was found in the protein fraction. In the presence of added ammonia, assimilation was greatly increased and no α-ketoglutaric acid was found in the supernatant fluid. Sodium azide partially inhibited incorporation into all major cell fractions, and at higher concentrations depressed the rate of glucose oxidation. During oxidative assimilation, chloramphenicol specifically inhibited the synthesis of protein. Oxidative assimilation of glucose by this organism did not appear to involve the synthesis of a primary product such as is found in the majority of bacteria. PMID:16561965

  20. Pseudomonas aeruginosa biofilm: potential therapeutic targets.

    PubMed

    Sharma, Garima; Rao, Saloni; Bansal, Ankiti; Dang, Shweta; Gupta, Sanjay; Gabrani, Reema

    2014-01-01

    Pseudomonas aeruginosa is a gram-negative pathogen that has become an important cause of infection, especially in patients with compromised host defense mechanisms. It is frequently related to nosocomial infections such as pneumonia, urinary tract infections (UTIs) and bacteremia. The biofilm formed by the bacteria allows it to adhere to any surface, living or non-living and thus Pseudomonal infections can involve any part of the body. Further, the adaptive and genetic changes of the micro-organisms within the biofilm make them resistant to all known antimicrobial agents making the Pseudomonal infections complicated and life threatening. Pel, Psl and Alg operons present in P. aeruginosa are responsible for the biosynthesis of extracellular polysaccharide which plays an important role in cell-cell and cell-surface interactions during biofilm formation. Understanding the bacterial virulence which depends on a large number of cell-associated and extracellular factors is essential to know the potential drug targets for future studies. Current novel methods like small molecule based inhibitors, phytochemicals, bacteriophage therapy, photodynamic therapy, antimicrobial peptides, monoclonal antibodies and nanoparticles to curtail the biofilm formed by P. aeruginosa are being discussed in this review. PMID:24309094

  1. Development of a Pseudomonas aeruginosa Agmatine Biosensor.

    PubMed

    Gilbertsen, Adam; Williams, Bryan

    2014-12-01

    Agmatine, decarboxylated arginine, is an important intermediary in polyamine production for many prokaryotes, but serves higher functions in eukaryotes such as nitric oxide inhibition and roles in neurotransmission. Pseudomonas aeruginosa relies on the arginine decarboxylase and agmatine deiminase pathways to convert arginine into putrescine. One of the two known agmatine deiminase operons, aguBA, contains an agmatine sensitive TetR promoter controlled by AguR. We have discovered that this promoter element can produce a titratable induction of its gene products in response to agmatine, and utilized this discovery to make a luminescent agmatine biosensor in P. aeruginosa. The genome of the P. aeruginosa lab strain UCBPP-PA14 was altered to remove both its ability to synthesize or destroy agmatine, and insertion of the luminescent reporter construct allows it to produce light in proportion to the amount of exogenous agmatine applied from ~100 nM to 1mM. Furthermore it does not respond to related compounds including arginine or putrescine. To demonstrate potential applications the biosensor was used to detect agmatine in spent supernatants, to monitor the development of arginine decarboxylase over time, and to detect agmatine in the spinal cords of live mice. PMID:25587430

  2. Polyclonal and monoclonal antibody therapy for experimental Pseudomonas aeruginosa pneumonia.

    PubMed Central

    Pennington, J E; Small, G J; Lostrom, M E; Pier, G B

    1986-01-01

    A human immunoglobulin G preparation, enriched in antibodies to lipopolysaccharide (LPS) Pseudomonas aeruginosa antigens (PA-IGIV) and murine monoclonal antibodies (MAb) to P. aeruginosa Fisher immunotype-1 (IT-1) LPS antigen and outer membrane protein F (porin), were evaluated for therapeutic efficacy in a guinea pig model of P. aeruginosa pneumonia. The concentration of antibodies to IT-1 LPS was 7.6 micrograms/ml in PA-IGIV and 478 micrograms/ml in the IT-1 MAb preparation. No antibody to IT-1 was detected in MAb to porin. For study, animals were infected by intratracheal instillation of IT-1 P. aeruginosa and then treated 2 h later with intravenous infusions of PA-IGIV, IT-1 MAb, or porin MAb. Control groups received intravenous albumin, and routinely died from pneumonia. Both PA-IGIV (500 mg/kg) and IT-1 MAb (greater than or equal to 2.5 mg/kg) treatment resulted in increased survival (P less than 0.01 to 0.001), and also improved intrapulmonary killing of bacteria. Porin MAb failed to protect from fatal pneumonia. IT-1 MAb treatment produced more survivals than did PA-IGIV treatment but only at dosages of MAb resulting in serum antibody concentrations greater than those achieved with PA-IGIV. PA-IGIV and IT-1 MAb demonstrated in vitro and in vivo (posttreatment guinea pig serum) opsonophagocytic activity for the IT-1 challenge strain. However, the polyclonal preparation required complement, whereas the MAb did not. We conclude that passive immunization with polyclonal hyperimmune P. aeruginosa globulin or with MAb to LPS antigens may be useful in the treatment of acute P. aeruginosa pneumonia. The relative efficacies of such preparations may be limited, however, by their type-specific LPS antibody concentrations. PMID:3093385

  3. 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

  4. 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

  5. Human targets of Pseudomonas aeruginosa pyocyanin

    PubMed Central

    Ran, Huimin; Hassett, Daniel J.; Lau, Gee W.

    2003-01-01

    Pseudomonas aeruginosa produces copious amounts of the redoxactive tricyclic compound pyocyanin that kills competing microbes and mammalian cells, especially during cystic fibrosis lung infection. Cross-phylum susceptibility to pyocyanin suggests the existence of evolutionarily conserved physiological targets. We screened a Saccharomyces cerevisiae deletion library to identify presumptive pyocyanin targets with the expectation that similar targets would be conserved in humans. Fifty S. cerevisiae targets were provisionally identified, of which 60% have orthologous human counterparts. These targets encompassed major cellular pathways involved in the cell cycle, electron transport and respiration, epidermal cell growth, protein sorting, vesicle transport, and the vacuolar ATPase. Using cultured human lung epithelial cells, we showed that pyocyanin-mediated reactive oxygen intermediates inactivate human vacuolar ATPase, supporting the validity of the yeast screen. We discuss how the inactivation of VATPase may negatively impact the lung function of cystic fibrosis patients. PMID:14605211

  6. Amino Acid Transport in Pseudomonas aeruginosa

    PubMed Central

    Kay, W. W.; Gronlund, Audrey F.

    1969-01-01

    Properties of the transport systems for amino acids in Pseudomonas aeruginosa were investigated. Exogenous 14C-labeled amino acids were shown to equilibrate with the internal native amino acid pool prior to incorporation into protein. When added at low external concentrations, the majority of the amino acids examined entered the protein of the cell unaltered. The rates of amino acid transport, established at low concentrations with 18 commonly occurring amino acids, varied as much as 40-fold. The transport process became saturated at high external amino acid concentrations, was temperature-sensitive, and was inhibited by sodium azide and iodoacetamide. Intracellular to extracellular amino acid ratios of 100- to 300-fold were maintained during exponential growth of the population in a glucose minimal medium. When the medium became depleted of glucose, neither extracellular nor intracellular amino acids could be detected. PMID:4974392

  7. Shear-enhanced adhesion of Pseudomonas aeruginosa

    NASA Astrophysics Data System (ADS)

    Lecuyer, Sigolene; Rusconi, Roberto; Shen, Yi; Forsyth, Alison; Stone, Howard

    2010-03-01

    Bacterial adhesion is the first step in the development of surface-associated communities known as biofilms, which are the cause of many problems in medical devices and industrial water systems. However the underlying mechanisms of initial bacterial attachment are not fully understood. We have investigated the effects of hydrodynamics on the probability of adsorption and detachment of Pseudomonas aeruginosa strain PA14 on model surfaces under flow, in straight microfluidic channels, and measured the distribution of bacteria residence time as a function of the shear rate. Our main discovery is a counter-intuitive enhanced adhesion as the shear stress is increased over a wide range of shear rates. In order to identify the origin of this phenomenon, we have performed experiments with several mutant strains. Our results show that shear-enhanced adhesion is not regulated by primary surface organelles, and that this process is not specific to a certain type of surface, but rather appears a general feature of the adhesive behavior of P. aeruginosa. These results suggest that shear-induced adhesion could be a very widespread strategy in nature.

  8. The Pseudomonas aeruginosa PA01 Gene Collection

    PubMed Central

    LaBaer, Joshua; Qiu, QingQing; Anumanthan, Anukanth; Mar, Wenhong; Zuo, Dongmei; Murthy, T.V.S.; Taycher, Helen; Halleck, Allison; Hainsworth, Eugenie; Lory, Stephen; Brizuela, Leonardo

    2004-01-01

    Pseudomonas aeruginosa, a common inhabitant of soil and water, is an opportunistic pathogen of growing clinical relevance. Its genome, one of the largest among bacteria [5570 open reading frames (ORFs)] approaches that of simple eukaryotes. We have constructed a comprehensive gene collection for this organism utilizing the annotated genome of P. aeruginosa PA01 and a highly automated and laboratory information management system (LIMS)-supported production line. All the individual ORFs have been successfully PCR-amplified and cloned into a recombination-based cloning system. We have isolated and archived four independent isolates of each individual ORF. Full sequence analysis of the first isolate for one-third of the ORFs in the collection has been completed. We used two sets of genes from this repository for high-throughput expression and purification of recombinant proteins in different systems. The purified proteins have been used to set up biochemical and immunological assays directed towards characterization of histidine kinases and identification of bacterial proteins involved in the immune response of cystic fibrosis patients. This gene repository provides a powerful tool for proteome- and genome-scale research of this organism, and the strategies adopted to generate this repository serve as a model for building clone sets for other bacteria. PMID:15489342

  9. Chromosomal Organization and Segregation in Pseudomonas aeruginosa

    PubMed Central

    Vallet-Gely, Isabelle; Boccard, Frédéric

    2013-01-01

    The study of chromosomal organization and segregation in a handful of bacteria has revealed surprising variety in the mechanisms mediating such fundamental processes. In this study, we further emphasized this diversity by revealing an original organization of the Pseudomonas aeruginosa chromosome. We analyzed the localization of 20 chromosomal markers and several components of the replication machinery in this important opportunistic γ-proteobacteria pathogen. This technique allowed us to show that the 6.3 Mb unique circular chromosome of P. aeruginosa is globally oriented from the old pole of the cell to the division plane/new pole along the oriC-dif axis. The replication machinery is positioned at mid-cell, and the chromosomal loci from oriC to dif are moved sequentially to mid-cell prior to replication. The two chromosomal copies are subsequently segregated at their final subcellular destination in the two halves of the cell. We identified two regions in which markers localize at similar positions, suggesting a bias in the distribution of chromosomal regions in the cell. The first region encompasses 1.4 Mb surrounding oriC, where loci are positioned around the 0.2/0.8 relative cell length upon segregation. The second region contains at least 800 kb surrounding dif, where loci show an extensive colocalization step following replication. We also showed that disrupting the ParABS system is very detrimental in P. aeruginosa. Possible mechanisms responsible for the coordinated chromosomal segregation process and for the presence of large distinctive regions are discussed. PMID:23658532

  10. 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

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

    PubMed

    Cutruzzolà, Francesca; Frankenberg-Dinkel, Nicole

    2016-01-01

    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

  12. 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

  13. 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

  14. Cystic fibrosis-niche adaptation of Pseudomonas aeruginosa reduces virulence in multiple infection hosts.

    PubMed

    Lorè, Nicola Ivan; Cigana, Cristina; De Fino, Ida; Riva, Camilla; Juhas, Mario; Schwager, Stephan; Eberl, Leo; Bragonzi, Alessandra

    2012-01-01

    The opportunistic pathogen Pseudomonas aeruginosa is able to thrive in diverse ecological niches and to cause serious human infection. P. aeruginosa environmental strains are producing various virulence factors that are required for establishing acute infections in several host organisms; however, the P. aeruginosa phenotypic variants favour long-term persistence in the cystic fibrosis (CF) airways. Whether P. aeruginosa strains, which have adapted to the CF-niche, have lost their competitive fitness in the other environment remains to be investigated. In this paper, three P. aeruginosa clonal lineages, including early strains isolated at the onset of infection, and late strains, isolated after several years of chronic lung infection from patients with CF, were analysed in multi-host model systems of acute infection. P. aeruginosa early isolates caused lethality in the three non-mammalian hosts, namely Caenorhabditis elegans, Galleria mellonella, and Drosophila melanogaster, while late adapted clonal isolates were attenuated in acute virulence. When two different mouse genetic background strains, namely C57Bl/6NCrl and Balb/cAnNCrl, were used as acute infection models, early P. aeruginosa CF isolates were lethal, while late isolates exhibited reduced or abolished acute virulence. Severe histopathological lesions, including high leukocytes recruitment and bacterial load, were detected in the lungs of mice infected with P. aeruginosa CF early isolates, while late isolates were progressively cleared. In addition, systemic bacterial spread and invasion of epithelial cells, which were detected for P. aeruginosa CF early strains, were not observed with late strains. Our findings indicate that niche-specific selection in P. aeruginosa reduced its ability to cause acute infections across a broad range of hosts while maintaining the capacity for chronic infection in the CF host. PMID:22558188

  15. Cystic Fibrosis-Niche Adaptation of Pseudomonas aeruginosa Reduces Virulence in Multiple Infection Hosts

    PubMed Central

    De Fino, Ida; Riva, Camilla; Juhas, Mario; Schwager, Stephan; Eberl, Leo; Bragonzi, Alessandra

    2012-01-01

    The opportunistic pathogen Pseudomonas aeruginosa is able to thrive in diverse ecological niches and to cause serious human infection. P. aeruginosa environmental strains are producing various virulence factors that are required for establishing acute infections in several host organisms; however, the P. aeruginosa phenotypic variants favour long-term persistence in the cystic fibrosis (CF) airways. Whether P. aeruginosa strains, which have adapted to the CF-niche, have lost their competitive fitness in the other environment remains to be investigated. In this paper, three P. aeruginosa clonal lineages, including early strains isolated at the onset of infection, and late strains, isolated after several years of chronic lung infection from patients with CF, were analysed in multi-host model systems of acute infection. P. aeruginosa early isolates caused lethality in the three non-mammalian hosts, namely Caenorhabditis elegans, Galleria mellonella, and Drosophila melanogaster, while late adapted clonal isolates were attenuated in acute virulence. When two different mouse genetic background strains, namely C57Bl/6NCrl and Balb/cAnNCrl, were used as acute infection models, early P. aeruginosa CF isolates were lethal, while late isolates exhibited reduced or abolished acute virulence. Severe histopathological lesions, including high leukocytes recruitment and bacterial load, were detected in the lungs of mice infected with P. aeruginosa CF early isolates, while late isolates were progressively cleared. In addition, systemic bacterial spread and invasion of epithelial cells, which were detected for P. aeruginosa CF early strains, were not observed with late strains. Our findings indicate that niche-specific selection in P. aeruginosa reduced its ability to cause acute infections across a broad range of hosts while maintaining the capacity for chronic infection in the CF host. PMID:22558188

  16. 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

  17. 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.

  18. Genome comparison of Pseudomonas aeruginosa large phages.

    PubMed

    Hertveldt, Kirsten; Lavigne, Rob; Pleteneva, Elena; Sernova, Natalia; Kurochkina, Lidia; Korchevskii, Roman; Robben, Johan; Mesyanzhinov, Vadim; Krylov, Victor N; Volckaert, Guido

    2005-12-01

    Pseudomonas aeruginosa phage EL is a dsDNA phage related to the giant phiKZ-like Myoviridae. The EL genome sequence comprises 211,215 bp and has 201 predicted open reading frames (ORFs). The EL genome does not share DNA sequence homology with other viruses and micro-organisms sequenced to date. However, one-third of the predicted EL gene products (gps) shares similarity (Blast alignments of 17-55% amino acid identity) with phiKZ proteins. Comparative EL and phiKZ genomics reveals that these giant phages are an example of substantially diverged genetic mosaics. Based on the position of similar EL and phiKZ predicted gene products, five genome regions can be delineated in EL, four of which are relatively conserved between EL and phiKZ. Region IV, a 17.7 kb genome region with 28 predicted ORFs, is unique to EL. Fourteen EL ORFs have been assigned a putative function based on protein similarity. Assigned proteins are involved in DNA replication and nucleotide metabolism (NAD+-dependent DNA ligase, ribonuclease HI, helicase, thymidylate kinase), host lysis and particle structure. EL-gp146 is the first chaperonin GroEL sequence identified in a viral genome. Besides a putative transposase, EL harbours predicted mobile endonucleases related to H-N-H and LAGLIDADG homing endonucleases associated with group I intron and intein intervening sequences. PMID:16256135

  19. 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

  20. 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

  1. 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

  2. Multiple erythematous nodules and ecthyma gangrenosum as a manifestation of Pseudomonas aeruginosa sepsis in a previously healthy infant.

    PubMed

    Duman, Murat; Ozdemir, Durgül; Yiş, Uluç; Köroğlu, Tolga F; Oren, Oğuz; Berktaş, Sema

    2006-01-01

    Pseudomonas aeruginosa septicemia is rare in healthy infants and children. Also not common, dermatologic manifestations such as ecthyma gangrenosum and indurated erythematous nodular lesions may be the first signs of pseudomonas infection, or may appear later in the course of the disease. Peripheral facial paralysis and mastoiditis are also rare and serious complications of acute otitis media caused by P. aeruginosa. We report a previously healthy 6-month-old boy who had an uncommon presentation and rare complications during the course of P. aeruginosa sepsis. PMID:16780471

  3. 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

  4. 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

  5. [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

  6. Surface action of gentamicin on Pseudomonas aeruginosa.

    PubMed Central

    Kadurugamuwa, J L; Clarke, A J; Beveridge, T J

    1993-01-01

    The mode of action of gentamicin has traditionally been considered to be at the 30S ribosomal level. However, the inhibition of bacterial protein synthesis alone appears to be insufficient to entirely explain the bactericidal effects. Bacteriolysis is also mediated through perturbation of the cell surface by gentamicin (J.L. Kadurugamuwa, J.S. Lam, and T.J. Beveridge, Antimicrob. Agents Chemother. 37:715-721, 1993). In order to separate the surface effect from protein synthesis in Pseudomonas aeruginosa PAO1, we chemically conjugated bovine serum albumin (BSA) to gentamicin, making the antibiotic too large to penetrate through the cell envelope to interact with the ribosomes of the cytoplasm. Furthermore, this BSA-gentamicin conjugate was also used to coat colloidal gold particles as a probe for electron microscopy to study the surface effect during antibiotic exposure. High-performance liquid chromatography confirmed the conjugation of the protein to the antibiotic. The conjugated gentamicin and BSA retained bactericidal activity and inhibited protein synthesis on isolated ribosomes in vitro but not on intact cells in vivo because of its exclusion from the cytoplasm. When reacted against the bacteria, numerous gentamicin-BSA-gold particles were clearly seen on the cell surfaces of whole mounts and thin sections of cells, while the cytoplasm was devoid of such particles. Disruption of the cell envelope was also observed since gentamicin-BSA and gentamicin-BSA-gold destabilized the outer membrane, evolved outer membrane blebs and vesicles, and formed holes in the cell surface. The morphological evidence suggests that the initial binding of the antibiotic disrupts the packing order of lipopolysaccharide of the outer membrane, which ultimately forms holes in the cell envelope and can lead to cell lysis. It is apparent that gentamicin has two potentially lethal effects on gram-negative cells, that resulting from inhibition of protein synthesis and that resulting from

  7. 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

  8. 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

  9. Bioleaching of copper oxide ore by Pseudomonas aeruginosa

    NASA Astrophysics Data System (ADS)

    Shabani, M. A.; Irannajad, M.; Azadmehr, A. R.; Meshkini, M.

    2013-12-01

    Bioleaching is an environmentally friendly method for extraction of metal from ores. In this study, bioleaching of copper oxide ore by Pseudomonas aeruginosa was investigated. Pseudomonas aeruginosa is a heterotrophic bacterium that can produce various organic acids in an appropriate culture medium, and these acids can operate as leaching agents. The parameters, such as particle size, glucose percentage in the culture medium, bioleaching time, and solid/liquid ratio were optimized. Optimum bioleaching conditions were found as follows: particle size of 150-177 μm, glucose percentage of 6%, bioleaching time of 8 d, and solid/liquid ratio of 1:80. Under these conditions, 53% of copper was extracted.

  10. 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

  11. 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

  12. Outbreak of hot-foot syndrome - caused by Pseudomonas aeruginosa.

    PubMed

    Michl, R K; Rusche, T; Grimm, S; Limpert, E; Beck, J F; Dost, A

    2012-07-01

    Infections with Pseudomonas aeruginosa can cause the hot-foot syndrome, presenting with painful plantar erythematous nodules. Particularly, the mechanically stressed areas of the foot are affected after contact with contaminated water from saunas, swimming pools, hot tubs, etc. We report an outbreak of hot-foot syndrome caused by Pseudomonas in 10 patients. The therapeutic regimens applied reached from local antiseptic therapy to systemic antibiotics. PMID:22187332

  13. Introduction of Pseudomonas aeruginosa into a Hospital via Vegetables

    PubMed Central

    Kominos, Spyros D.; Copeland, Charles E.; Grosiak, Barbara; Postic, Bosko

    1972-01-01

    Pseudomonas aeruginosa was isolated from tomatoes, radishes, celery, carrots, endive, cabbage, cucumbers, onions, and lettuce obtained from the kitchen of a general hospital, with tomatoes yielding both highest frequencies of isolation and highest counts. Presence of P. aeruginosa on the hands of kitchen personnel and cutting boards and knives which they used suggests acquisition of the organism through contact with these vegetables. It is estimated that a patient consuming an average portion of tomato salad might ingest as many as 5 × 103 colony-forming units of P. aeruginosa. Pyocine types of P. aeruginosa isolated from clinical specimens were frequently identical to those recovered from vegetables, thus implicating tomatoes and other vegetables as an important source and vehicle by which P. aeruginosa colonizes the intestinal tract of patients. PMID:4628795

  14. 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

  15. Targeting iron uptake to control Pseudomonas aeruginosa infections in cystic fibrosis.

    PubMed

    Smith, Daniel J; Lamont, Iain L; Anderson, Greg J; Reid, David W

    2013-12-01

    The aerobic Gram-negative bacterium Pseudomonas aeruginosa is an opportunistic pathogen responsible for life-threatening acute and chronic infections in humans. As part of chronic infection P. aeruginosa forms biofilms, which shield the encased bacteria from host immune clearance and provide an impermeable and protective barrier against currently available antimicrobial agents. P. aeruginosa has an absolute requirement for iron for infection success. By influencing cell-cell communication (quorum sensing) and virulence factor expression, iron is a powerful regulator of P. aeruginosa behaviour. Consequently, the imposed perturbation of iron acquisition systems has been proposed as a novel therapeutic approach to the treatment of P. aeruginosa biofilm infection. In this review, we explore the influence of iron availability on P. aeruginosa infection in the lungs of the people with the autosomal recessive condition cystic fibrosis as an archetypal model of chronic P. aeruginosa biofilm infection. Novel therapeutics aimed at disrupting P. aeruginosa are discussed, with an emphasis placed on identifying the barriers that need to be overcome in order to translate these promising in vitro agents into effective therapies in human pulmonary infections. PMID:23143541

  16. Gene expression in Pseudomonas aeruginosa swarming motility

    PubMed Central

    2010-01-01

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

  17. 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

  18. 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

  19. Agricultural Plants and Soil as a Reservoir for Pseudomonas aeruginosa

    PubMed Central

    Green, Sylvia K.; Schroth, Milton N.; Cho, John J.; Kominos, Spyros D.; Vitanza-Jack, Vilma B.

    1974-01-01

    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

  20. 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

  1. 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

  2. Genome diversity of Pseudomonas aeruginosa PAO1 laboratory strains.

    PubMed

    Klockgether, Jens; Munder, Antje; Neugebauer, Jens; Davenport, Colin F; Stanke, Frauke; Larbig, Karen D; Heeb, Stephan; Schöck, Ulrike; Pohl, Thomas M; Wiehlmann, Lutz; Tümmler, Burkhard

    2010-02-01

    Pseudomonas aeruginosa PAO1 is the most commonly used strain for research on this ubiquitous and metabolically versatile opportunistic pathogen. Strain PAO1, a derivative of the original Australian PAO isolate, has been distributed worldwide to laboratories and strain collections. Over decades discordant phenotypes of PAO1 sublines have emerged. Taking the existing PAO1-UW genome sequence (named after the University of Washington, which led the sequencing project) as a blueprint, the genome sequences of reference strains MPAO1 and PAO1-DSM (stored at the German Collection for Microorganisms and Cell Cultures [DSMZ]) were resolved by physical mapping and deep short read sequencing-by-synthesis. MPAO1 has been the source of near-saturation libraries of transposon insertion mutants, and PAO1-DSM is identical in its SpeI-DpnI restriction map with the original isolate. The major genomic differences of MPAO1 and PAO1-DSM in comparison to PAO1-UW are the lack of a large inversion, a duplication of a mobile 12-kb prophage region carrying a distinct integrase and protein phosphatases or kinases, deletions of 3 to 1,006 bp in size, and at least 39 single-nucleotide substitutions, 17 of which affect protein sequences. The PAO1 sublines differed in their ability to cope with nutrient limitation and their virulence in an acute murine airway infection model. Subline PAO1-DSM outnumbered the two other sublines in late stationary growth phase. In conclusion, P. aeruginosa PAO1 shows an ongoing microevolution of genotype and phenotype that jeopardizes the reproducibility of research. High-throughput genome resequencing will resolve more cases and could become a proper quality control for strain collections. PMID:20023018

  3. 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. PMID:27297477

  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. 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

  6. 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. PMID:25172858

  7. Expression of pili from Bacteroides nodosus in Pseudomonas aeruginosa.

    PubMed Central

    Elleman, T C; Hoyne, P A; Stewart, D J; McKern, N M; Peterson, J E

    1986-01-01

    The pili of Bacteroides nodosus, the causative agent of ovine footrot, constitute the major host-protective immunogen against homologous serotypic challenge. The pilin gene from B. nodosus 198 has been cloned and morphologically expressed as extracellular pili in Pseudomonas aeruginosa by using a plasmid-borne, thermoregulated expression system. B. nodosus pilin could not be detected in cultures of P. aeruginosa grown at 32 degrees C, but after induction at 37 degrees C, B. nodosus pili were expressed on the cell surface of P. aeruginosa to the virtual exclusion of the host cell pili. Pili harvested from induced P. aeruginosa cultures were used to immunize sheep against footrot. The serum agglutinating antibody titers of vaccinated sheep were comparable to those of sheep receiving pili from B. nodosus. Subsequent challenge of the sheep with B. nodosus 198 indicated that the recombinant- DNA-derived pili vaccine and the B. nodosus pili vaccine provided similar levels of protection against footrot. Images PMID:2877967

  8. Suppression of fungal growth exhibited by Pseudomonas aeruginosa.

    PubMed Central

    Kerr, J R

    1994-01-01

    Three surgery patients were monitored postoperatively, with particular reference to lung infection. In each case there was a clinical impression that Pseudomonas aeruginosa suppressed the growth of Candida albicans in patients with clinically significant lung infections from whom both of these organisms were isolated from serial sputum samples. Regrowth of C. albicans after P. aeruginosa eradication occurred in two patients, despite fluconazole therapy, to which both C. albicans isolates were susceptible. In all three patients, the strain of P. aeruginosa was found to inhibit the growth of the corresponding C. albicans strain in vitro. Further in vitro susceptibility studies revealed significant inhibition by 10 strains of P. aeruginosa of 11 strains of fungi known to infect humans; these were Candida krusei, Candida keyfr, Candida guillermondii, Candida tropicalis, Candida lusitaniae, Candida parapsilosis, Candida pseudotropicalis, Candida albicans, Torulopsis glabrata, Saccharomyces cerevisiae, and Aspergillus fumigatus. PMID:8150966

  9. 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

  10. 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

  11. Binding of protegrin-1 to Pseudomonas aeruginosa and Burkholderia cepacia

    PubMed Central

    Albrecht, Mark T; Wang, Wei; Shamova, Olga; Lehrer, Robert I; Schiller, Neal L

    2002-01-01

    Background Pseudomonas aeruginosa and Burkholderia cepacia infections of cystic fibrosis patients' lungs are often resistant to conventional antibiotic therapy. Protegrins are antimicrobial peptides with potent activity against many bacteria, including P. aeruginosa. The present study evaluates the correlation between protegrin-1 (PG-1) sensitivity/resistance and protegrin binding in P. aeruginosa and B. cepacia. Methods The PG-1 sensitivity/resistance and PG-1 binding properties of P. aeruginosa and B. cepacia were assessed using radial diffusion assays, radioiodinated PG-1, and surface plasmon resonance (BiaCore). Results The six P. aeruginosa strains examined were very sensitive to PG-1, exhibiting minimal active concentrations from 0.0625–0.5 μg/ml in radial diffusion assays. In contrast, all five B. cepacia strains examined were greater than 10-fold to 100-fold more resistant, with minimal active concentrations ranging from 6–10 μg/ml. When incubated with a radioiodinated variant of PG-1, a sensitive P. aeruginosa strain bound considerably more protegrin molecules per cell than a resistant B. cepacia strain. Binding/diffusion and surface plasmon resonance assays revealed that isolated lipopolysaccharide (LPS) and lipid A from the sensitive P. aeruginosa strains bound PG-1 more effectively than LPS and lipid A from resistant B. cepacia strains. Conclusion These findings support the hypothesis that the relative resistance of B. cepacia to protegrin is due to a reduced number of PG-1 binding sites on the lipid A moiety of its LPS. PMID:11980587

  12. Influence of zinc on Pseudomonas aeruginosa susceptibilities to imipenem.

    PubMed Central

    Cooper, G L; Louie, A; Baltch, A L; Chu, R C; Smith, R P; Ritz, W J; Michelsen, P

    1993-01-01

    Serial dilution susceptibility testing of imipenem against 59 clinical isolates of Pseudomonas aeruginosa, conducted simultaneously on single lots of Difco and BBL Mueller-Hinton agar (MHA), resulted in MICs for 90% of strains tested of 8 and 16 micrograms/ml, respectively. MICs for Escherichia coli, Klebsiella pneumoniae, and Pseudomonas spp. were also higher on BBL MHA. Quantification of the cation content of the two MHAs by atomic absorption spectroscopy demonstrated that the zinc concentration in BBL MHA was 15 times greater than that measured in Difco MHA (2.61 and 0.17 micrograms/ml, respectively). Concentrations of calcium, magnesium, iron, manganese, and copper in the two agars were similar. Addition of zinc to Difco MHA resulted in increases in MICs of imipenem for P. aeruginosa but not in the MICs of ceftazidime or cefpirome for P. aeruginosa (P < 0.01). A lesser zinc effect was seen on the activity of imipenem against E. coli, K. pneumoniae, and Pseudomonas spp. The activities of ceftazidime and cefpirome were similar on both MHAs when tested against all gram-negative organisms in this study. Thus, the effect of zinc in MHA was clearly demonstrated by a significant increase in the MICs of imipenem for P. aeruginosa, and, to a lesser extent, for other gram-negative bacilli. PMID:8408557

  13. Qingfei Xiaoyan Wan, a traditional Chinese medicine formula, ameliorates Pseudomonas aeruginosa-induced acute lung inflammation by regulation of PI3K/AKT and Ras/MAPK pathways.

    PubMed

    Hou, Yuanyuan; Nie, Yan; Cheng, Binfeng; Tao, Jin; Ma, Xiaoyao; Jiang, Min; Gao, Jie; Bai, Gang

    2016-05-01

    Gram-negative pathogen-induced nosocomial infections and resistance are a most serious menace to global public health. Qingfei Xiaoyan Wan (QF), a traditional Chinese medicine (TCM) formula, has been used clinically in China for the treatment of upper respiratory tract infections, acute or chronic bronchitis and pulmonary infection. In this study, the effects of QF on Pseudomonas aeruginosa-induced acute pneumonia in mice were evaluated. The mechanisms by which four typical anti-inflammatory ingredients from QF, arctigenin (ATG), cholic acid (CLA), chlorogenic acid (CGA) and sinapic acid (SPA), regulate anti-inflammatory signaling pathways and related targets were investigated using molecular biology and molecular docking techniques. The results showed that pretreatment with QF significantly inhibits the release of cytokines (TNF-α and IL-6) and chemokines (IL-8 and RANTES), reduces leukocytes recruitment into inflamed tissues and ameliorates pulmonary edema and necrosis. In addition, ATG was identified as the primary anti-inflammatory agent with action on the PI3K/AKT and Ras/MAPK pathways. CLA and CGA enhanced the actions of ATG and exhibited synergistic NF-κB inactivation effects possibly via the Ras/MAPK signaling pathway. Moreover, CLA is speculated to target FGFR and MEK firstly. Overall, QF regulated the PI3K/AKT and Ras/MAPK pathways to inhibit pathogenic bacterial infections effectively. PMID:27175332

  14. Involvement of Pseudomonas aeruginosa rhodanese in protection from cyanide toxicity.

    PubMed

    Cipollone, Rita; Frangipani, Emanuela; Tiburzi, Federica; Imperi, Francesco; Ascenzi, Paolo; Visca, Paolo

    2007-01-01

    Cyanide is a serious environmental pollutant and a biocontrol metabolite in plant growth-promoting Pseudomonas species. Here we report on the presence of multiple sulfurtransferases in the cyanogenic bacterium Pseudomonas aeruginosa PAO1 and investigate in detail RhdA, a thiosulfate:cyanide sulfurtransferase (rhodanese) which converts cyanide to less toxic thiocyanate. RhdA is a cytoplasmic enzyme acting as the principal rhodanese in P. aeruginosa. The rhdA gene forms a transcriptional unit with the PA4955 and psd genes and is controlled by two promoters located upstream of PA4955 and rhdA. Both promoters direct constitutive RhdA expression and show similar patterns of activity, involving moderate down-regulation at the stationary phase or in the presence of exogenous cyanide. We previously observed that RhdA overproduction protects Escherichia coli against cyanide toxicity, and here we show that physiological RhdA levels contribute to P. aeruginosa survival under cyanogenic conditions. The growth of a DeltarhdA mutant is impaired under cyanogenic conditions and fully restored upon complementation with rhdA. Wild-type P. aeruginosa outcompetes the DeltarhdA mutant in cyanogenic coculture assays. Hence, RhdA could be regarded as an effector of P. aeruginosa intrinsic resistance to cyanide, insofar as it provides the bacterium with a defense mechanism against endogenous cyanide toxicity, in addition to cyanide-resistant respiration. PMID:17098912

  15. 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.

  16. [Structural components and peculiarities of Pseudomonas aeruginosa biofilm organization].

    PubMed

    Balko, O B; Avdieieva, L V

    2010-01-01

    Peculiarities of the structural organization of bacterial biofilm during its formation and disintegration have been investigated on the model of Pseudomonas aeruginosa UCM B-900 (ATCC 9027). It was shown, that development of the biofilm in a stationary system on glass was a two-vector process with changes in time and space. P. aeruginosa UCM B-900 biofilm is formed from single cells, passes through the stages of base components, net structure, islands and comes to the end with integration into a complete monolayer. The biofilm degradation repeats the stages of its formation in the reverse sequence. PMID:20812507

  17. Cell-to-cell signaling and Pseudomonas aeruginosa infections.

    PubMed Central

    Van Delden, C.; Iglewski, B. H.

    1998-01-01

    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. Cell-to-cell signaling systems control the expression and allow a coordinated, cell-density-dependent production of many extracellular virulence factors. We discuss the possible role of cell-to-cell signaling in the pathogenesis of P. aeruginosa infections and present a rationale for targeting cell-to-cell signaling systems in the development of new therapeutic approaches. PMID:9866731

  18. 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

  19. Comparative sensitivity and resistance of some strains of Pseudomonas aeruginosa and Pseudomonas stutzeri to antibacterial agents

    PubMed Central

    Russell, A. D.; Mills, A. P.

    1974-01-01

    A comparison has been made of the sensitivities to various antibiotic and non-antibiotic substances of some strains of Pseudomonas aeruginosa and P. stutzeri, the latter including strains isolated from eye and other cosmetic products and from other sources. Whereas P. aeruginosa strains showed a high resistance to cetrimide and to benzalkonium chloride, the P. stutzeri strains were generally more sensitive to these and to chlorhexidine. The P. stutzeri strains were also more sensitive to the various antibiotics tested. The loss of the ability to transfer an R factor by two strains of P. aeruginosa caused no significant change in their drug sensitivity pattern. PMID:4369876

  20. 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

  1. 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

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

    PubMed

    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

  3. ZnuA and zinc homeostasis in Pseudomonas aeruginosa

    PubMed Central

    Pederick, Victoria G.; Eijkelkamp, Bart A.; Begg, Stephanie L.; Ween, Miranda P.; McAllister, Lauren J.; Paton, James C.; McDevitt, Christopher A.

    2015-01-01

    Pseudomonas aeruginosa is a ubiquitous environmental bacterium and a clinically significant opportunistic human pathogen. Central to the ability of P. aeruginosa to colonise both environmental and host niches is the acquisition of zinc. Here we show that P. aeruginosa PAO1 acquires zinc via an ATP-binding cassette (ABC) permease in which ZnuA is the high affinity, zinc-specific binding protein. Zinc uptake in Gram-negative organisms predominantly occurs via an ABC permease, and consistent with this expectation a P. aeruginosa ΔznuA mutant strain showed an ~60% reduction in cellular zinc accumulation, while other metal ions were essentially unaffected. Despite the major reduction in zinc accumulation, minimal phenotypic differences were observed between the wild-type and ΔznuA mutant strains. However, the effect of zinc limitation on the transcriptome of P. aeruginosa PAO1 revealed significant changes in gene expression that enable adaptation to low-zinc conditions. Genes significantly up-regulated included non-zinc-requiring paralogs of zinc-dependent proteins and a number of novel import pathways associated with zinc acquisition. Collectively, this study provides new insight into the acquisition of zinc by P. aeruginosa PAO1, revealing a hitherto unrecognized complexity in zinc homeostasis that enables the bacterium to survive under zinc limitation. PMID:26290475

  4. Interference with Pseudomonas quinolone signal synthesis inhibits virulence factor expression by Pseudomonas aeruginosa

    PubMed Central

    Calfee, M. Worth; Coleman, James P.; Pesci, Everett C.

    2001-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that controls numerous virulence factors through intercellular signals. This bacterium has two quorum-sensing systems (las and rhl), which act through the intercellular signals N-(3-oxododecanoyl)-l-homoserine lactone (3-oxo-C12-HSL) and N-butyryl-l-homoserine lactone (C4-HSL), respectively. P. aeruginosa also produces a third intercellular signal that is involved in virulence factor regulation. This signal, 2-heptyl-3-hydroxy-4-quinolone [referred to as the Pseudomonas quinolone signal (PQS)], is a secondary metabolite that is part of the P. aeruginosa quorum-sensing hierarchy. PQS can induce both lasB (encodes LasB elastase) and rhlI (encodes the C4-HSL synthase) in P. aeruginosa and is produced maximally during the late stationary phase of growth. Because PQS is an intercellular signal that is part of the quorum-sensing hierarchy and controls multiple virulence factors, we began basic studies designed to elucidate its biosynthetic pathway. First, we present data that strongly suggest that anthranilate is a precursor for PQS. P. aeruginosa converted radiolabeled anthranilate into radioactive PQS, which was bioactive. We also found that an anthranilate analog (methyl anthranilate) would inhibit the production of PQS. This analog was then shown to have a major negative effect on elastase production by P. aeruginosa. These data provide evidence that precursors of intercellular signals may provide viable targets for the development of therapeutic treatments that will reduce P. aeruginosa virulence. PMID:11573001

  5. Is levofloxacin as active as ciprofloxacin against Pseudomonas aeruginosa?

    PubMed

    Bonfiglio, G

    2001-01-01

    The in vitro activity of levofloxacin against 300 Pseudomonas aeruginosa isolated from hospitalized patients, with the exception of those recovered in intensive care or hematology units, was compared to ofloxacin, ciprofloxacin, piperacillin, amikacin, ceftazidime and imipenem. Imipenem showed the best activity (81.6%), followed by piperacillin (80.7%). The activity of levofloxacin was equal to that of ciprofloxacin (75.3%) but was more active than ofloxacin (58.1%). Moreover, the MIC values of levofloxacin did not show any statistical difference using two different inocula. Levofloxacin shows an excellent bactericidal activity being generally within one doubling dilution of the MIC. These results were also confirmed by the time-killing studies. In conclusion, according to the in vitro activity, levofloxacin could be considered a good option for the treatment of infections sustained by Pseudomonas aeruginosa, and clinical experiments are required to corroborate our in vitro data. PMID:11399859

  6. Structure of a putative acetyltransferase (PA1377) from Pseudomonas aeruginosa

    SciTech Connect

    Davies, Anna M.; Tata, Renée; Chauviac, François-Xavier; Sutton, Brian J.; Brown, Paul R.

    2008-05-01

    The crystal structure of an acetyltransferase encoded by the gene PA1377 from Pseudomonas aeruginosa has been determined at 2.25 Å resolution. Comparison with a related acetyltransferase revealed a structural difference in the active site that was taken to reflect a difference in substrate binding and/or specificity between the two enzymes. Gene PA1377 from Pseudomonas aeruginosa encodes a 177-amino-acid conserved hypothetical protein of unknown function. The structure of this protein (termed pitax) has been solved in space group I222 to 2.25 Å resolution. Pitax belongs to the GCN5-related N-acetyltransferase family and contains all four sequence motifs conserved among family members. The β-strand structure in one of these motifs (motif A) is disrupted, which is believed to affect binding of the substrate that accepts the acetyl group from acetyl-CoA.

  7. Fatty Acids Synthesized from Hexadecane by Pseudomonas aeruginosa

    PubMed Central

    Romero, Ethel M.; Brenner, Rodolfo R.

    1966-01-01

    Romero, Ethel M. (Universidad Nacional de la Plata, La Plata, Argentina), and Rodolfo M. Brenner. Fatty acids synthesized from hexadecane by Pseudomonas aeruginosa. J. Bacteriol. 91:183–188. 1966.—The lipids extracted from Pseudomonas aeruginosa incubated with hexadecane in a mineral medium were separated into a nonpolar and three polar fractions by thin-layer chromatography. The fatty acid composition of the four cellular fractions and that of the lipids excreted into the medium was studied by gas-liquid chromatography. Saturated fatty acids with 14 to 22 carbons were recognized, together with monoenoic, dienoic, and hydroxylated acids. Hydroxylated fatty acids were principally found in two polar fractions containing rhamnose and glucose; the other polar fraction, containing serine, alanine, ethanolamine, and leucine, was richer in monoenoic fatty acids. Octadecadienoic acid was found in the neutral fraction. PMID:4955247

  8. 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

  9. PcrV antibody-antibiotic combination improves survival in Pseudomonas aeruginosa-infected mice.

    PubMed

    Song, Y; Baer, M; Srinivasan, R; Lima, J; Yarranton, G; Bebbington, C; Lynch, S V

    2012-08-01

    The type III secretion system (TTSS) of Pseudomonas aeruginosa, associated with acute infection, facilitates the direct injection of cytotoxins into the host cell cytoplasm. Mab166, a murine monoclonal antibody against PcrV, a protein located at the tip of the injectisome, has demonstrated efficacy against P. aeruginosa infection, resulting in reduced lung injury and increased survival in murine models of infection. We hypothesised that the administration of Mab166 in combination with an antibiotic would further improve the survival of P. aeruginosa-infected mice. A murine model of P. aeruginosa acute infection, three clinically relevant antibiotics (ciprofloxacin, tobramycin and ceftazidime) and the Mab166 antibody were used for this study. Consistently, compared to other treatment groups (antibiotic or antibody administered in isolation), the combination of Mab166 and antibiotic significantly improved the survival of mice infected with three times the lethal dose (LD(90)) of the highly cytotoxic ExoU-secreting strain, PA103. This synergistic effect was primarily due to enhanced bactericidal effect and protection against lung injury, which prevented bacterial dissemination to other organs. Hence, the combination of Mab166 with antibiotic administration provides a new, more effective strategy against P. aeruginosa airway infection, especially when large numbers of highly virulent strains are present. PMID:22187351

  10. 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

  11. 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

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

    PubMed

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

    1992-06-01

    The authors present a case of phlegmonous gastritis in a 65 year old patient. The diagnosis was made in the operating room and the treatment was conservative; no gastric resection was done. This clinical entity is interesting because it is a least frequent pathology, the pathogenic bacteria which was the cause (Pseudomona aeruginosa) has at this time not been reported in the literature, including the favorable outcome of the patient without gastric resection. PMID:1633018

  13. Monoclonal antibodies to Pseudomonas aeruginosa ferripyochelin-binding protein.

    PubMed Central

    Sokol, P A; Woods, D E

    1986-01-01

    Hybridomas secreting specific monoclonal antibodies against the Pseudomonas aeruginosa ferripyochelin-binding protein (FBP) were isolated. These monoclonal antibodies reacted with FBP in immunoblots of outer membrane preparations from all serotypes of P. aeruginosa. Two of the monoclonal antibodies also reacted with FBP in strains of P. putida, P. fluorescens, and P. stutzeri. These antibodies did not react with outer membranes of P. cepacia, "P. multivorans," P. maltophilia, or other gram-negative organisms. The monoclonal antibodies were opsonophagocytic and blocked the binding of [59Fe]ferripyochelin to isolated outer membranes of strain PAO. By indirect immunofluorescence techniques, the monoclonal antibodies were used to demonstrate that FBP is present on the cell surface of P. aeruginosa cells grown in low-iron but not high-iron medium. These observations were confirmed by using 125I in surface-labeling techniques. Images PMID:3091506

  14. Sphingoid long chain bases prevent lung infection by Pseudomonas aeruginosa

    PubMed Central

    Pewzner-Jung, Yael; Tavakoli Tabazavareh, Shaghayegh; Grassmé, Heike; Becker, Katrin Anne; Japtok, Lukasz; Steinmann, Jörg; Joseph, Tammar; Lang, Stephan; Tuemmler, Burkhard; Schuchman, Edward H; Lentsch, Alex B; Kleuser, Burkhard; Edwards, Michael J; Futerman, Anthony H; Gulbins, Erich

    2014-01-01

    Cystic fibrosis patients and patients with chronic obstructive pulmonary disease, trauma, burn wound, or patients requiring ventilation are susceptible to severe pulmonary infection by Pseudomonas aeruginosa. Physiological innate defense mechanisms against this pathogen, and their alterations in lung diseases, are for the most part unknown. We now demonstrate a role for the sphingoid long chain base, sphingosine, in determining susceptibility to lung infection by P. aeruginosa. Tracheal and bronchial sphingosine levels were significantly reduced in tissues from cystic fibrosis patients and from cystic fibrosis mouse models due to reduced activity of acid ceramidase, which generates sphingosine from ceramide. Inhalation of mice with sphingosine, with a sphingosine analog, FTY720, or with acid ceramidase rescued susceptible mice from infection. Our data suggest that luminal sphingosine in tracheal and bronchial epithelial cells prevents pulmonary P. aeruginosa infection in normal individuals, paving the way for novel therapeutic paradigms based on inhalation of acid ceramidase or of sphingoid long chain bases in lung infection. PMID:25085879

  15. 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

  16. 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

  17. 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

  18. 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. PMID:26874276

  19. Full Virulence of Pseudomonas aeruginosa Requires OprF▿

    PubMed Central

    Fito-Boncompte, Laurène; Chapalain, Annelise; Bouffartigues, Emeline; Chaker, Hichem; Lesouhaitier, Olivier; Gicquel, Gwendoline; Bazire, Alexis; Madi, Amar; Connil, Nathalie; Véron, Wilfried; Taupin, Laure; Toussaint, Bertrand; Cornelis, Pierre; Wei, Qing; Shioya, Koki; Déziel, Eric; Feuilloley, Marc G. J.; Orange, Nicole; Dufour, Alain; Chevalier, Sylvie

    2011-01-01

    OprF is a general outer membrane porin of Pseudomonas aeruginosa, a well-known human opportunistic pathogen associated with severe hospital-acquired sepsis and chronic lung infections of cystic fibrosis patients. A multiphenotypic approach, based on the comparative study of a wild-type strain of P. aeruginosa, its isogenic oprF mutant, and an oprF-complemented strain, showed that OprF is required for P. aeruginosa virulence. The absence of OprF results in impaired adhesion to animal cells, secretion of ExoT and ExoS toxins through the type III secretion system (T3SS), and production of the quorum-sensing-dependent virulence factors pyocyanin, elastase, lectin PA-1L, and exotoxin A. Accordingly, in the oprF mutant, production of the signal molecules N-(3-oxododecanoyl)-l-homoserine lactone and N-butanoyl-l-homoserine lactone was found to be reduced and delayed, respectively. Pseudomonas quinolone signal (PQS) production was decreased, while its precursor, 4-hydroxy-2-heptylquinoline (HHQ), accumulated in the cells. Taken together, these results show the involvement of OprF in P. aeruginosa virulence, at least partly through modulation of the quorum-sensing network. This is the first study showing a link between OprF, PQS synthesis, T3SS, and virulence factor production, providing novel insights into virulence expression. PMID:21189321

  20. Full virulence of Pseudomonas aeruginosa requires OprF.

    PubMed

    Fito-Boncompte, Laurène; Chapalain, Annelise; Bouffartigues, Emeline; Chaker, Hichem; Lesouhaitier, Olivier; Gicquel, Gwendoline; Bazire, Alexis; Madi, Amar; Connil, Nathalie; Véron, Wilfried; Taupin, Laure; Toussaint, Bertrand; Cornelis, Pierre; Wei, Qing; Shioya, Koki; Déziel, Eric; Feuilloley, Marc G J; Orange, Nicole; Dufour, Alain; Chevalier, Sylvie

    2011-03-01

    OprF is a general outer membrane porin of Pseudomonas aeruginosa, a well-known human opportunistic pathogen associated with severe hospital-acquired sepsis and chronic lung infections of cystic fibrosis patients. A multiphenotypic approach, based on the comparative study of a wild-type strain of P. aeruginosa, its isogenic oprF mutant, and an oprF-complemented strain, showed that OprF is required for P. aeruginosa virulence. The absence of OprF results in impaired adhesion to animal cells, secretion of ExoT and ExoS toxins through the type III secretion system (T3SS), and production of the quorum-sensing-dependent virulence factors pyocyanin, elastase, lectin PA-1L, and exotoxin A. Accordingly, in the oprF mutant, production of the signal molecules N-(3-oxododecanoyl)-l-homoserine lactone and N-butanoyl-l-homoserine lactone was found to be reduced and delayed, respectively. Pseudomonas quinolone signal (PQS) production was decreased, while its precursor, 4-hydroxy-2-heptylquinoline (HHQ), accumulated in the cells. Taken together, these results show the involvement of OprF in P. aeruginosa virulence, at least partly through modulation of the quorum-sensing network. This is the first study showing a link between OprF, PQS synthesis, T3SS, and virulence factor production, providing novel insights into virulence expression. PMID:21189321

  1. 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.

  2. Lagooning of wastewaters favors dissemination of clinically relevant Pseudomonas aeruginosa.

    PubMed

    Petit, Stéphanie M-C; Lavenir, Raphaël; Colinon-Dupuich, Céline; Boukerb, Amine M; Cholley, Pascal; Bertrand, Xavier; Freney, Jean; Doléans-Jordheim, Anne; Nazaret, Sylvie; Laurent, Frédéric; Cournoyer, Benoit

    2013-10-01

    The significance of wastewater treatment lagoons (WWTLs) as point sources of clinically relevant Pseudomonas aeruginosa that can disseminate through rural and peri-urban catchments was investigated. A panel of P. aeruginosa strains collected over three years from WWTLs and community-acquired infections was compared by pulsed field gel electrophoresis (PFGE) DNA fingerprinting and multilocus sequence typing (MLST). Forty-four distantly related PFGE profiles and four clonal complexes were found among the WWTL strains analyzed. Some genotypes were repeatedly detected from different parts of WWTLs, including the influent, suggesting an ability to migrate and persist over time. MLST showed all investigated lineages to match sequence types described in other countries and strains from major clinical clones such as PA14 of ST253 and "C" of ST17 were observed. Some of these genotypes matched isolates from community-acquired infections recorded in the WWTL geographic area. Most WWTL strains harbored the main P. aeruginosa virulence genes; 13% harbored exoU-encoded cytoxins, but on at least six different genomic islands, with some of these showing signs of genomic instability. P. aeruginosa appeared to be highly successful opportunistic colonizers of WWTLs. Lagooning of wastewaters was found to favor dissemination of clinically relevant P. aeruginosa among peri-urban watersheds. PMID:23792168

  3. A network biology approach to denitrification in Pseudomonas aeruginosa

    DOE PAGESBeta

    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

  4. 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

  5. Update on the treatment of Pseudomonas aeruginosa pneumonia.

    PubMed

    El Solh, Ali A; Alhajhusain, Ahmad

    2009-08-01

    Pseudomonas aeruginosa is an important cause of nosocomial pneumonia associated with a high morbidity and mortality rate. This bacterium expresses a variety of factors that confer resistance to a broad array of antimicrobial agents. Empirical antibiotic therapy is often inadequate because cultures from initial specimens grow strains that are resistant to initial antibiotics. Surveillance data, hospital antibiogram and individualization of regimens based on prior antibiotic use may reduce the risk of inadequate therapy. The use of combination therapies for P. aeruginosa pneumonia has been a long-advocated practice, but the potential increased value of combination therapy over monotherapy remains controversial. Doripenem and biapenem are new carbapenems that have excellent activity against P. aeruginosa; however, they lack activity against strains that express resistance to the currently available carbapenems. The polymyxins remain the most consistently effective agents against multidrug-resistant P. aeruginosa. Strains that are panantibiotic-resistant are rare, but their incidence is increasing. Antibiotic combinations that yield some degree of susceptibility in vitro are the recourse, although the efficacy of these regimens has yet to be established in clinical studies. Experimental polypeptides may provide a new therapeutic approach. Among these, the anti-PcrV immunoglobulin G antibody that blocks the type III secretion system-mediated virulence of P. aeruginosa has recently entered Phase I/II clinical trials. PMID:19520717

  6. Long Term Chronic Pseudomonas aeruginosa Airway Infection in Mice

    PubMed Central

    Facchini, Marcella; De Fino, Ida; Riva, Camilla; Bragonzi, Alessandra

    2014-01-01

    A mouse model of chronic airway infection is a key asset in cystic fibrosis (CF) research, although there are a number of concerns regarding the model itself. Early phases of inflammation and infection have been widely studied by using the Pseudomonas aeruginosa agar-beads mouse model, while only few reports have focused on the long-term chronic infection in vivo. The main challenge for long term chronic infection remains the low bacterial burden by P. aeruginosa and the low percentage of infected mice weeks after challenge, indicating that bacterial cells are progressively cleared by the host. This paper presents a method for obtaining efficient long-term chronic infection in mice. This method is based on the embedding of the P. aeruginosa clinical strains in the agar-beads in vitro, followed by intratracheal instillation in C57Bl/6NCrl mice. Bilateral lung infection is associated with several measurable read-outs including weight loss, mortality, chronic infection, and inflammatory response. The P. aeruginosa RP73 clinical strain was preferred over the PAO1 reference laboratory strain since it resulted in a comparatively lower mortality, more severe lesions, and higher chronic infection. P. aeruginosa colonization may persist in the lung for over three months. Murine lung pathology resembles that of CF patients with advanced chronic pulmonary disease. This murine model most closely mimics the course of the human disease and can be used both for studies on the pathogenesis and for the evaluation of novel therapies. PMID:24686327

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

    PubMed

    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

  8. 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

  9. 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

  10. [Pseudomonas aeruginosa colonisation in bronchiectatic patients and clinical reflections].

    PubMed

    Kömüs, Nuray; Tertemiz, Kemal Can; Akkoçlu, Atila; Gülay, Zeynep; Yilmaz, Erkan

    2006-01-01

    Bronchiectasis is characterized with irreversible dilatation according to destruction of epithelium, elastic and muscular layer. Most important cause of bronchiectasis is chronic bacterial infections. Pseudomonas aeruginosa colonisation is frequently seen in bronchiectatic patients. We aimed to find out P. aeruginosa colonisation frequency and clinical, radiological and spirometric reflections due to colonisation. We analysed 83 cases retrospectively. Mean age was 58.2 and 54.2% of them were female. Bronchiectasis were localised 19.3% in left lung, 19.3% right and 61.4% bilaterally. 29 (35.8%) normal, 28 (34.6%) obstructive, 7 (8.6%) restrictive, 17 (21%) mixed type disorders are detected in spirometric measures. Sputum culture performed in 50 cases. No microorganism colonisation determined in 30 (60%) cases, P. aeruginosa colonisation 16 (32%), Haemophilus influenzae 2 (4%), 1 (2%) Streptococcus pneumoniae and Proteus mirabilis 1 (2%) cases. P. aeruginosa colonisation determined more frequent in males (p<0.05). No significant correlation detected between colonisation and age or smoking habits (p>0.05). In cases with colonisation; clubbing and hemoptysis were significantly frequent (p<0.05). Only peribronchial thickening was significantly correlated with colonisation in radiological findings (p<0.05). In blood gase analysis PaO2, oxygen saturation were lower and PaCO2 higher in cases colonised with P. aeruginosa but it was not statisticaly significant (p>0.05). Hospitalization rate was higher in P. aeruginosa colonised cases (p>0.05). It is an important problem about mortality because of higher hemoptysis and hospitalisation requirement rate in P. aeruginosa colonised cases. PMID:17203422

  11. 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

  12. Pseudomonas aeruginosa Displays Multiple Phenotypes during Development as a Biofilm

    PubMed Central

    Sauer, Karin; Camper, Anne K.; Ehrlich, Garth D.; Costerton, J. William; Davies, David G.

    2002-01-01

    Complementary approaches were employed to characterize transitional episodes in Pseudomonas aeruginosa biofilm development using direct observation and whole-cell protein analysis. Microscopy and in situ reporter gene analysis were used to directly observe changes in biofilm physiology and to act as signposts to standardize protein collection for two-dimensional electrophoretic analysis and protein identification in chemostat and continuous-culture biofilm-grown populations. Using these approaches, we characterized five stages of biofilm development: (i) reversible attachment, (ii) irreversible attachment, (iii) maturation-1, (iv) maturation-2, and (v) dispersion. Biofilm cells were shown to change regulation of motility, alginate production, and quorum sensing during the process of development. The average difference in detectable protein regulation between each of the five stages of development was 35% (approximately 525 proteins). When planktonic cells were compared with maturation-2 stage biofilm cells, more than 800 proteins were shown to have a sixfold or greater change in expression level (over 50% of the proteome). This difference was higher than when planktonic P. aeruginosa were compared with planktonic cultures of Pseudomonas putida. Las quorum sensing was shown to play no role in early biofilm development but was important in later stages. Biofilm cells in the dispersion stage were more similar to planktonic bacteria than to maturation-2 stage bacteria. These results demonstrate that P. aeruginosa displays multiple phenotypes during biofilm development and that knowledge of stage-specific physiology may be important in detecting and controlling biofilm growth. PMID:11807075

  13. 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

  14. Modulation of Type III Secretion System in Pseudomonas aeruginosa: Involvement of the PA4857 Gene Product

    PubMed Central

    Zhu, Miao; Zhao, Jingru; Kang, Huaping; Kong, Weina; Zhao, Yuanyu; Wu, Min; Liang, Haihua

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that causes serious acute or chronic infections in humans. Acute infections typically involve the type III secretion systems (T3SSs) and bacterial motility, whereas chronic infections are often associated with biofilm formation and the type VI secretion system. To identify new genes required for pathogenesis, a transposon mutagenesis library was constructed and the gene PA4857, named tspR, was found to modulate T3SS gene expression. Deletion of P. aeruginosa tspR reduced the virulence in a mouse acute lung infection model and diminished cytotoxicity. Suppression of T3SS gene expression in the tspR mutant resulted from compromised translation of the T3SS master regulator ExsA. TspR negatively regulated two small RNAs, RsmY and RsmZ, which control RsmA. Our data demonstrated that defects in T3SS expression and biofilm formation in retS mutant could be partially restored by overexpression of tspR. Taken together, our results demonstrated that the newly identified retS-tspR pathway is coordinated with the retS-gacS system, which regulates the genes associated with acute and chronic infections and controls the lifestyle choice of P. aeruginosa. PMID:26858696

  15. Characterisation of Pseudomonas aeruginosa related to bovine mastitis.

    PubMed

    Park, Hye Rim; Hong, Min Ki; Hwang, Sun Young; Park, Young Kyung; Kwon, Ka Hee; Yoon, Jang Won; Shin, Sook; Kim, Jae Hong; Park, Yong Ho

    2014-03-01

    Pseudomonas aeruginosa is one of the causative pathogens of bovine mastitis. Most P. aeruginosa strains possess the type III secretion system (TTSS), which may increase somatic cell counts (SCCs) in milk from mastitis-affected cows. Moreover, most of P. aeruginosa cells can form biofilms, thereby reducing antibiotic efficacy. In this study, the presence and effect of TTSS-related genotypes on increase of SCCs among 122 P. aeruginosa isolates obtained from raw milk samples from mastitis-affected cows and their antibiotic susceptibility at planktonic and biofilm status were investigated. Based on the presence of TTSS-related genes a total of 82.7% of the isolates were found to harbour exoU and/or exoS genes, including the invasive (exoU-/exoS+, 69.4%), cytotoxic (exoU+/exoS-, 8.3%) and cytotoxic/invasive strains (exoU+/ exoS+, 5.0%). Milk containing exoS-positive isolates had higher SCCs than those containing exoS-negative isolates. The majority of isolates showed gentamicin, amikacin, meropenem and ciprofloxacin susceptibility at planktonic status. However, the susceptibility was decreased at the biofilm status. Based on minimum biofilm eradication concentration (MBEC)/minimum inhibitory concentration (MIC) ratios, the range of change in antibiotic susceptibility varied widely depending on the antibiotics (from ≥ 3.1-fold to ≥ 475.0-fold). In conclusion, most P. aeruginosa isolates studied here had a genotype related to increase in SCCs. The efficiency of antibiotic therapy against P. aeruginosa-related bovine mastitis could be improved by analysing both the MBEC and the MIC of isolates. PMID:24334080

  16. [Susceptibility and resistence of Pseudomonas aeruginosa to antimicrobial agents].

    PubMed

    Gamero Delgado, M C; García-Mayorgas, A D; Rodríguez, F; Ibarra, A; Casal, M

    2007-06-01

    Pseudomonas aeruginosa is an opportunistic microorganism that is frequently the cause of nosocomial infections. Multiple mechanisms are involved in its natural and acquired resistance to many of the antimicrobial agents commonly used in clinical practice. The objective of this study was to assess the susceptibility and resistance patterns of P. aeruginosa strains isolated in Hospital Reina Sofia between 2000 and 2005, as well as to analyze the differences between intrahospital and extrahospital isolates in 2005 and to compare the results with those obtained in other studies. A total of 3,019 strains of P. aeruginosa from different hospitals and nonhospital settings were evaluated, taking into consideration their degree of sensitivity to different antibiotics. The MICs were determined by means of the Wider I automated system (Soria Melguizo), taking into consideration the criteria of susceptibility and resistance recommended by MENSURA. Results of the analysis showed that P. aeruginosa maintained similar levels of antimicrobial susceptibility during the period 2000-2005, with increased susceptibility to amikacin, gentamicin and tobramycin. There were also important differences in the degree of susceptibility between intrahospital and extrahospital strains, except for imipenem and fosfomycin. The intrahospital difference in susceptibility was also evaluated, emphasizing the importance of periodically studying susceptibility and resistance patterns of P. aeruginosa in each setting in order to evaluate different therapeutic guidelines, as it is not always advisable to extrapolate data from different regions. These differences can be explained by the different use of antibiotics in each center and the geographic variations of the resistance mechanisms of P. aeruginosa. PMID:17893761

  17. Structural genes for salicylate biosynthesis from chorismate in Pseudomonas aeruginosa.

    PubMed

    Serino, L; Reimmann, C; Baur, H; Beyeler, M; Visca, P; Haas, D

    1995-11-15

    Salicylate is a precursor of pyochelin in Pseudomonas aeruginosa and both compounds display siderophore activity. To elucidate the salicylate biosynthetic pathway, we have cloned and sequenced a chromosomal region of P. aeruginosa PAO1 containing two adjacent genes, designated pchB and pchA, which are necessary for salicylate formation. The pchA gene encodes a protein of 52 kDa with extensive similarity to the chorismate-utilizing enzymes isochorismate synthase, anthranilate synthase (component I) and p-aminobenzoate synthase (component I), whereas the 11 kDa protein encoded by pchB does not show significant similarity with other proteins. The pchB stop codon overlaps the presumed pchA start codon. Expression of the pchA gene in P. aeruginosa appears to depend on the transcription and translation of the upstream pchB gene. The pchBA genes are the first salicylate biosynthetic genes to be reported. Salicylate formation was demonstrated in an Escherichia coli entC mutant lacking isochorismate synthase when this strain expressed both the pchBA genes, but not when it expressed pchB alone. By contrast, an entB mutant of E. coli blocked in the conversion of isochorismate to 2,3-dihydro-2,3-dihydroxybenzoate formed salicylate when transformed with a pchB expression construct. Salicylate formation could also be demonstrated in vitro when chorismate was incubated with a crude extract of P. aeruginosa containing overproduced PchA and PchB proteins; salicylate and pyruvate were formed in equimolar amounts. Furthermore, salicylate-forming activity could be detected in extracts from a P. aeruginosa pyoverdin-negative mutant when grown under iron limitation, but not with iron excess. Our results are consistent with a pathway leading from chorismate to isochorismate and then to salicylate plus pyruvate, catalyzed consecutively by the iron-repressible PchA and PchB proteins in P. aeruginosa. PMID:7500944

  18. Autophagy protects C. elegans against necrosis during Pseudomonas aeruginosa infection

    PubMed Central

    Zou, Cheng-Gang; Ma, Yi-Cheng; Dai, Li-Li; Zhang, Ke-Qin

    2014-01-01

    Autophagy, a conserved pathway that delivers intracellular materials into lysosomes for degradation, is involved in development, aging, and a variety of diseases. Accumulating evidence demonstrates that autophagy plays a protective role against infectious diseases by diminishing intracellular pathogens, including bacteria, viruses, and parasites. However, the mechanism by which autophagy regulates innate immunity remains largely unknown. Here, we show that autophagy is involved in host defense against a pathogenic bacterium Pseudomonas aeruginosa in the metazoan Caenorhabditis elegans. P. aeruginosa infection induces autophagy via a conserved extracellular signal-regulated kinase (ERK). Intriguingly, impairment of autophagy does not influence the intestinal accumulation of P. aeruginosa, but instead induces intestinal necrosis. Inhibition of necrosis results in the survival of autophagy-deficient worms after P. aeruginosa infection. These findings reveal a previously unidentified role for autophagy in protection against necrosis triggered by pathogenic bacteria in C. elegans and implicate that such a function of autophagy may be conserved through the inflammatory response in diverse organisms. PMID:25114220

  19. [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

  20. 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

  1. 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

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

    PubMed

    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

  3. 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

  4. 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

  5. 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.

  6. Novel Strategies for the Treatment of Pseudomonas aeruginosa Infections.

    PubMed

    Wagner, Stefanie; Sommer, Roman; Hinsberger, Stefan; Lu, Cenbin; Hartmann, Rolf W; Empting, Martin; Titz, Alexander

    2016-07-14

    Infections with Pseudomonas aeruginosa have become a concerning threat in hospital-acquired infections and for cystic fibrosis patients. The major problem leading to high mortality lies in the appearance of drug-resistant strains. Therefore, a vast number of approaches to develop novel anti-infectives is currently pursued. These diverse strategies span from killing (new antibiotics) to disarming (antivirulence) the pathogen. Particular emphasis lies on the development of compounds that inhibit biofilms formed in chronic infections to restore susceptibility toward antibiotics. Numerous promising results are summarized in this perspective. Antibiotics with a novel mode of action will be needed to avoid cross resistance against currently used therapeutic agents. Importantly, antivirulence drugs are expected to yield a significantly reduced rate of resistance development. Most developments are still far from the application. It can however be expected that combination therapies, also containing antivirulence agents, will pave the way toward novel treatment options against P. aeruginosa. PMID:26804741

  7. Biofilm Matrix and Its Regulation in Pseudomonas aeruginosa

    PubMed Central

    Wei, Qing; Ma, Luyan Z.

    2013-01-01

    Biofilms are communities of microorganisms embedded in extracellular polymeric substances (EPS) matrix. Bacteria in biofilms demonstrate distinct features from their free-living planktonic counterparts, such as different physiology and high resistance to immune system and antibiotics that render biofilm a source of chronic and persistent infections. A deeper understanding of biofilms will ultimately provide insights into the development of alternative treatment for biofilm infections. The opportunistic pathogen Pseudomonas aeruginosa, a model bacterium for biofilm research, is notorious for its ability to cause chronic infections by its high level of drug resistance involving the formation of biofilms. In this review, we summarize recent advances in biofilm formation, focusing on the biofilm matrix and its regulation in P. aeruginosa, aiming to provide resources for the understanding and control of bacterial biofilms. PMID:24145749

  8. Morphogenetic expression of Bacteroides nodosus fimbriae in Pseudomonas aeruginosa.

    PubMed Central

    Mattick, J S; Bills, M M; Anderson, B J; Dalrymple, B; Mott, M R; Egerton, J R

    1987-01-01

    Type 4 fimbriae are found in a range of pathogenic bacteria, including Bacteroides nodosus, Moraxella bovis, Neisseria gonorrhoeae, and Pseudomonas aeruginosa. The structural subunits of these fimbriae all contain a highly conserved hydrophobic amino-terminal sequence preceding a variable hydrophilic carboxy-terminal region. We show here that recombinant P. aeruginosa cells containing the B. nodosus fimbrial subunit gene under the control of a strong promoter (pL, from bacteriophage lambda) produced large amounts of fimbriae that were structurally and antigenically indistinguishable from those produced by B. nodosus. This was demonstrated by fimbrial isolation and purification, electrophoretic and Western transfer analyses, and immunogold labeling and electron microscopy. These results suggest that type 4 fimbriated bacteria use a common mechanism for fimbrial assembly and that the structural subunits are interchangeable, thereby providing a basis for the development of multivalent vaccines. Images PMID:2878919

  9. 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. PMID:26403431

  10. Biosurfactants production by Pseudomonas aeruginosa FR using palm oil.

    PubMed

    Oliveira, Fernando J S; Vazquez, Leonardo; De Campos, Norberto P; de França, Francisca P

    2006-03-01

    Biosurfactants production by a strain of Pseudomonas aeruginosa using palm oil as a sole carbon source was investigated. The experiments were carried out in 500-mL conical flasks containing 100 mL of mineral media supplemented with palm oil as the sole carbon source. The P. aeruginosa FR strain was able to reduce surface tension of three tested inorganic media. Rotation velocities from 100 to 150 rpm provided free-cell fermented media with the lowest surface tension of approx 33 mN/m. Emulsification index results of even 100% were achieved when diesel was used as oil phase. Eight surface-active compounds produced by the bacterium were identified by mass spectrometry. PMID:18563649

  11. 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.

  12. 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

  13. Necrotizing stomatitis: report of 3 Pseudomonas aeruginosa-positive patients.

    PubMed

    Barasch, Andrei; Gordon, Sara; Geist, Rose Y; Geist, James R

    2003-08-01

    Necrotizing oral lesions have been described in immunosuppressed patients, usually in association with gingival and periodontal pathoses. The etiology of these lesions has not been completely elucidated. We present 3 patients with a type of necrotizing stomatitis in which clinical patterns appear distinct from the periodontal forms of the disease. The lesions yielded bacterial cultures positive for Pseudomonas aeruginosa and reverted to no growth in 2 patients after proper antibiotic therapy. We propose that P aeruginosa may be responsible for selected necrotizing oral lesions with a clinical presentation lacking typical necrotizing periodontal disease and that this condition may represent the intraoral counterpart of ecthyma gangrenosum. In such cases, bacterial culture of the lesion becomes imperative because the disease does not respond to typical periodontal and antimicrobial therapy. PMID:12931084

  14. Streptococcus pneumoniae and Pseudomonas aeruginosa pneumonia induce distinct host responses

    PubMed Central

    McConnell, Kevin W.; McDunn, Jonathan E.; Clark, Andrew T.; Dunne, W. Michael; Dixon, David J.; Turnbull, Isaiah R.; DiPasco, Peter J.; Osberghaus, William F.; Sherman, Benjamin; Martin, James R.; Walter, Michael J.; Cobb, J. Perren; Buchman, Timothy G.; Hotchkiss, Richard S.; Coopersmith, Craig M.

    2009-01-01

    Objective Pathogens that cause pneumonia may be treated in a targeted fashion by antibiotics, but if this therapy fails, treatment involves only non-specific supportive measures, independent of the inciting infection. The purpose of this study was to determine whether host response is similar following disparate infections with similar mortalities. Design Prospective, randomized controlled study. Setting Animal laboratory in a university medical center. Interventions Pneumonia was induced in FVB/N mice by either Streptococcus pneumoniae or two different concentrations of Pseudomonas aeruginosa. Plasma and bronchoalveolar lavage fluid from septic animals was assayed by a microarray immunoassay measuring 18 inflammatory mediators at multiple timepoints. Measurements and Main Results The host response was dependent upon the causative organism as well as kinetics of mortality, but the pro- and anti- inflammatory response was independent of inoculum concentration or degree of bacteremia. Pneumonia caused by different concentrations of the same bacteria, Pseudomonas aeruginosa, also yielded distinct inflammatory responses; however, inflammatory mediator expression did not directly track the severity of infection. For all infections, the host response was compartmentalized, with markedly different concentrations of inflammatory mediators in the systemic circulation and the lungs. Hierarchical clustering analysis resulted in the identification of 5 distinct clusters of the host response to bacterial infection. Principal components analysis correlated pulmonary MIP-2 and IL-10 with progression of infection while elevated plasma TNFsr2 and MCP-1 were indicative of fulminant disease with >90% mortality within 48 hours. Conclusions Septic mice have distinct local and systemic responses to Streptococcus pneumoniae and Pseudomonas aeruginosa pneumonia. Targeting specific host inflammatory responses induced by distinct bacterial infections could represent a potential therapeutic

  15. Characterization of a rhodanese from the cyanogenic bacterium Pseudomonas aeruginosa.

    PubMed

    Cipollone, Rita; Bigotti, Maria Giulia; Frangipani, Emanuela; Ascenzi, Paolo; Visca, Paolo

    2004-12-01

    Pseudomonas aeruginosa, the rRNA group I type species of genus Pseudomonas, is a Gram-negative, aerobic bacterium responsible for serious infection in humans. P. aeruginosa pathogenicity has been associated with the production of several virulence factors, including cyanide. Here, the biochemical characterization of recombinant P. aeruginosa rhodanese (Pa RhdA), catalyzing the sulfur transfer from thiosulfate to a thiophilic acceptor, e.g., cyanide, is reported. Sequence homology analysis of Pa RhdA predicts the sulfur-transfer reaction to occur through persulfuration of the conserved catalytic Cys230 residue. Accordingly, the titration of active Pa RhdA with cyanide indicates the presence of one extra sulfur bound to the Cys230 Sgamma atom per active enzyme molecule. Values of K(m) for thiosulfate binding to Pa RhdA are 1.0 and 7.4mM at pH 7.3 and 8.6, respectively, and 25 degrees C. However, the value of K(m) for cyanide binding to Pa RhdA (=14 mM, at 25 degrees C) and the value of V(max) (=750 micromol min(-1)mg(-1), at 25 degrees C) for the Pa RhdA-catalyzed sulfur-transfer reaction are essentially pH- and substrate-independent. Therefore, the thiosulfate-dependent Pa RhdA persulfuration is favored at pH 7.3 (i.e., the cytosolic pH of the bacterial cell) rather than pH 8.6 (i.e., the standard pH for rhodanese activity assay). Within this pH range, conformational change(s) occur at the Pa RhdA active site during the catalytic cycle. As a whole, rhodanese may participate in multiple detoxification mechanisms protecting P. aeruginosa from endogenous and environmental cyanide. PMID:15522204

  16. 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.

  17. 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

  18. Locus of the Pseudomonas aeruginosa toxin A gene.

    PubMed Central

    Hanne, L F; Howe, T R; Iglewski, B H

    1983-01-01

    The gene for Pseudomonas aeruginosa toxin A has been mapped in the late region of the chromosome of strain PAO. Strain PAO-PR1, which produces parental levels of toxin A antigen that is enzymatically inactive and nontoxic, was used as the donor for R68.45 plasmid-mediated genetic exchange. Strain PAO-PR1 (toxA1) was mated with toxin A-producing strains, and exconjugates for selected prototrophic markers were tested for the transfer of toxA1. The toxA1 gene was located between cnu-9001 and pur-67 at approximately 85 min on the PAO chromosome. PMID:6403508

  19. Phosphorylated tyrosine in the flagellum filament protein of Pseudomonas aeruginosa

    SciTech Connect

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

    1990-09-01

    Purified flagella from two strains of {sup 32}P-labeled Pseudomonas aeruginosa were shown to be phosphorylated. This was confirmed by autoradiography of flagellin protein in polyacrylamide gels. Thin-layer electrophoresis and autoradiography of flagellin partial hydrolysates indicated that phosphotyrosine was the major phosphorylated amino acid. High-pressure liquid chromatographic analysis confirmed the presence of phosphotyrosine in flagellum filament protein. Preliminary data indicated that less than one tyrosine per subunit was phosphorylated. No evidence was found for phosphorylation of serine or threonine. A function related to tyrosine phosphorylation has not been determined.

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

    PubMed Central

    Bharathi, Shabana; Raman, Ganesh V; Mohan, Dhavalikar Mrunali; Krishnan, Anjana

    2014-01-01

    We report a case of blebitis that occurred 3 years later following a combined glaucoma and cataract surgery. It was an atypical presentation, as patient had no classical fiery looking signs of blebitis despite the isolated organism being Pseudomonas aeruginosa. Improvized surgical techniques like use of Mitomycin C, releasable flap sutures though considered as part of the recommended procedure for better surgical outcomes, their role as potential risk factors for visually blinding complications like endophthalmitis are often overlooked. This case report throws light on such risk factors for bleb associated infections and recommends removal or trimming of all releasable sutures and the need for a regular postoperative follow-up. PMID:25370403

  1. Mapping of mutations in Pseudomonas aeruginosa defective in pyoverdin production.

    PubMed Central

    Ankenbauer, R; Hanne, L F; Cox, C D

    1986-01-01

    Twelve mutants of Pseudomonas aeruginosa PAO defective in pyoverdin production were isolated (after chemical and transposon mutagenesis) that were nonfluorescent and unable to grow on medium containing 400 microM ethylenediaminedi(o-hydroxyphenylacetic acid). Four mutants were unable to produce hydroxamate, six were hydroxamate positive, one was temperature sensitive for pyoverdin production, and another was unable to synthesize pyoverdin on succinate minimal medium but was capable of synthesizing pyoverdin when grown on Casamino Acids medium (Difco Laboratories, Detroit, Mich.). The mutations were mapped on the PAO chromosome. All the mutations affecting pyoverdin production were located at 65 to 70 min, between catA1 and mtu-9002. PMID:3087966

  2. Computer Simulation of the Rough Lipopolysaccharide Membrane of Pseudomonas Aeruginosa

    SciTech Connect

    Lins, Roberto D.; Straatsma, TP

    2001-08-01

    Lipopolysaccharides (LPS) form the major constituent of the outer membrane of Gram-negative bacteria, and are believed to play a key role in processes that govern microbial metal binding, microbial adsorption to mineral surfaces, and microbe mediated oxidation/reduction reactions at the bacterial exterior surface. A computational modeling capability is being developed for the study of geochemical reactions at the outer bacterial envelope of Gram-negative bacteria. The understanding of these mechanisms is crucial for the development of successful environmental bioremediation strategies. A molecular model for the rough LPS of Pseudomonas aeruginosa has been designed based on available experimentally determined structural information.

  3. Secretion of Elastinolytic Enzymes and Their Propeptides by Pseudomonas aeruginosa

    PubMed Central

    Braun, Peter; de Groot, Arjan; Bitter, Wilbert; Tommassen, Jan

    1998-01-01

    Elastase of Pseudomonas aeruginosa is synthesized as a preproenzyme. The signal sequence is cleaved off during transport across the inner membrane and, in the periplasm, proelastase is further processed. We demonstrate that the propeptide and the mature elastase are both secreted but that the propeptide is degraded extracellularly. In addition, reduction of the extracellular proteolytic activity led to the accumulation of unprocessed forms of LasA and LasD in the extracellular medium, which shows that these enzymes are secreted in association with their propeptides. Furthermore, a hitherto undefined protein with homology to a Streptomyces griseus aminopeptidase accumulated under these conditions. PMID:9642203

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

    PubMed

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

    1998-07-01

    Elastase of Pseudomonas aeruginosa is synthesized as a preproenzyme. The signal sequence is cleaved off during transport across the inner membrane and, in the periplasm, proelastase is further processed. We demonstrate that the propeptide and the mature elastase are both secreted but that the propeptide is degraded extracellularly. In addition, reduction of the extracellular proteolytic activity led to the accumulation of unprocessed forms of LasA and LasD in the extracellular medium, which shows that these enzymes are secreted in association with their propeptides. Furthermore, a hitherto undefined protein with homology to a Streptomyces griseus aminopeptidase accumulated under these conditions. PMID:9642203

  5. Intraclonal genome diversity of the major Pseudomonas aeruginosa clones C and PA14.

    PubMed

    Fischer, Sebastian; Klockgether, Jens; Morán Losada, Patricia; Chouvarine, Philippe; Cramer, Nina; Davenport, Colin F; Dethlefsen, Sarah; Dorda, Marie; Goesmann, Alexander; Hilker, Rolf; Mielke, Samira; Schönfelder, Torben; Suerbaum, Sebastian; Türk, Oliver; Woltemate, Sabrina; Wiehlmann, Lutz; Tümmler, Burkhard

    2016-04-01

    Bacterial populations differentiate at the subspecies level into clonal complexes. Intraclonal genome diversity was studied in 100 isolates of the two dominant Pseudomonas aeruginosa clones C and PA14 collected from the inanimate environment, acute and chronic infections. The core genome was highly conserved among clone members with a median pairwise within-clone single nucleotide sequence diversity of 8 × 10(-6) for clone C and 2 × 10(-5) for clone PA14. The composition of the accessory genome was, on the other hand, as variable within the clone as between unrelated clones. Each strain carried a large cargo of unique genes. The two dominant worldwide distributed P. aeruginosa clones combine an almost invariant core with the flexible gain and loss of genetic elements that spread by horizontal transfer. PMID:26711897

  6. Successful Management of Multidrug-Resistant Pseudomonas aeruginosa Pneumonia after Kidney Transplantation in a Dog

    PubMed Central

    PARK, Kyung-Mee; NAM, Hyun-Suk; WOO, Heung-Myong

    2013-01-01

    ABSTRACT An 8-year-old male mongrel dog that had undergone renal transplantation was presented 25 days later with an acute cough, anorexia and exercise intolerance. During the investigation, neutrophilic leukocytosis was noted, and thoracic radiographs revealed caudal lung lobe infiltration. While being treated with two broad-spectrum antibiotics, clinical signs worsened. Pneumonia due to infection with multidrug-resistant (MDR) Pseudomonas (P.) aeruginosa, sensitive only to imipenem and amikacin, was confirmed by bacteria isolation. After treatment with imipenem-cilastatin without reducing the immunosuppressant dose, clinical signs completely resolved. During the 2-year follow-up period, no recurrence was observed. To the best of authors’ knowledge, this is the first report of pneumonia caused by MDR P. aeruginosa in a renal recipient dog and successful management of this disease. PMID:23842146

  7. 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

  8. 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

  9. Inhaled Lactonase Reduces Pseudomonas aeruginosa Quorum Sensing and Mortality in Rat Pneumonia

    PubMed Central

    Lafleur, John; Lepidi, Hubert; Papazian, Laurent; Rolain, Jean-Marc; Raoult, Didier; Elias, Mikael; Silby, Mark W.; Bzdrenga, Janek; Bregeon, Fabienne; Chabriere, Eric

    2014-01-01

    Rationale The effectiveness of antibiotic molecules in treating Pseudomonas aeruginosa pneumonia is reduced as a result of the dissemination of bacterial resistance. The existence of bacterial communication systems, such as quorum sensing, has provided new opportunities of treatment. Lactonases efficiently quench acyl-homoserine lactone-based bacterial quorum sensing, implicating these enzymes as potential new anti-Pseudomonas drugs that might be evaluated in pneumonia. Objectives The aim of the present study was to evaluate the ability of a lactonase called SsoPox-I to reduce the mortality of a rat P. aeruginosa pneumonia. Methods To assess SsoPox-I-mediated quorum quenching, we first measured the activity of the virulence gene lasB, the synthesis of pyocianin, the proteolytic activity of a bacterial suspension and the formation of biofilm of a PAO1 strain grown in the presence of lactonase. In an acute lethal model of P. aeruginosa pneumonia in rats, we evaluated the effects of an early or deferred intra-tracheal treatment with SsoPox-I on the mortality, lung bacterial count and lung damage. Measurements and Primary Results SsoPox-I decreased PAO1 lasB virulence gene activity, pyocianin synthesis, proteolytic activity and biofilm formation. The early use of SsoPox-I reduced the mortality of rats with acute pneumonia from 75% to 20%. Histological lung damage was significantly reduced but the lung bacterial count was not modified by the treatment. A delayed treatment was associated with a non-significant reduction of mortality. Conclusion These results demonstrate the protective effects of lactonase SsoPox-I in P. aeruginosa pneumonia and open the way for a future therapeutic use. PMID:25350373

  10. Characterization of protease IV expression in Pseudomonas aeruginosa clinical isolates.

    PubMed

    Conibear, Tim C R; Willcox, Mark D P; Flanagan, Judith L; Zhu, Hua

    2012-02-01

    Expression of protease IV by Pseudomonas aeruginosa during ocular infections contributes significantly to tissue damage. However, several P. aeruginosa strains isolated from ocular infections or inflammatory events produce very low levels of protease IV. The aim of the present study was to characterize, genetically and phenotypically, the presence and expression of the protease IV gene in a group of clinical isolates that cause adverse ocular events of varying degrees, and to elucidate the possible control mechanisms of expression associated with this virulence factor. Protease IV gene sequences from seven clinical isolates of P. aeruginosa were determined and compared to P. aeruginosa strains PAO1 and PA103-29. Production and enzyme activity of protease IV were measured in test strains and compared to that of quorum-sensing gene (lasRI) mutants and the expression of other virulence factors. Protease IV gene sequence similarities between the isolates were 97.5-99.5 %. The strains were classified into two distinct phylogenetic groups that correlated with the presence of exo-enzymes from type three secretion systems (TTSS). Protease IV concentrations produced by PAOΔlasRI mutants and the two clinical isolates with a lasRI gene deficiency were restored to levels comparable to strain PAO1 following complementation of the quorum-sensing gene deficiencies. The protease IV gene is highly conserved in P. aeruginosa clinical isolates that cause a range of adverse ocular events. Observed variations within the gene sequence appear to correlate with presence of specific TTSS genes. Protease IV expression was shown to be regulated by the Las quorum-sensing system. PMID:21921113

  11. Antibacterial activity of Lawsonia inermis Linn (Henna) against Pseudomonas aeruginosa

    PubMed Central

    Habbal, O; Hasson, SS; El-Hag, AH; Al-Mahrooqi, Z; Al-Hashmi, N; Al-Bimani, Z; Al-Balushi, MS; Al-Jabri, AA

    2011-01-01

    Objective To investigate the antibacterial activity of henna (Lawsonia inermis Linn) obtained from different regions of Oman against a wide array of micro-organisms. Methods Fresh henna samples were obtained from different regions of Oman as leaves and seeds. 100 g fresh and dry leaves and 50 g of fresh and dry seeds were separately soaked in 500 mL of ethanol for three days, respectively, with frequent agitation. The mixture was filtered, and the crude extract was collected. The crude extract was then heated, at 48 °C in a water bath to evaporate its liquid content. The dry crude henna extract was then tested for its antibacterial activity using well-diffusion antibiotic susceptibility technique. Henna extracts were investigated for their antibacterial activity at different concentrations against a wide array of different micro-organisms including a laboratory standard bacterial strain of Pseudomonas aeruginosa (NCTC 10662) (P. aeruginosa) and eleven fresh clinical isolates of P. aeruginosa obtained from patients attending the Sultan Qaboos University Hospital (SQUH). 2-Hydroxy-p-Nathoqinone-Tech (2-HPNT, MW=174.16, C10H6O3) was included as control (at 50% concentration) along with the henna samples tested. Results Henna samples demonstrated antibacterial activity against all isolates but the highest susceptibility was against P. aeruginosa with henna samples obtained from Al-sharqyia region. Conclusions Omani henna from Al-sharqyia region demonstrates high in vitro anti-P. aeruginosa activity compared with many henna samples from different regions of Oman. PMID:23569753

  12. Ferritin and ferrihydrite nanoparticles as iron sources for Pseudomonas aeruginosa

    PubMed Central

    Dehner, Carolyn; Morales-Soto, Nydia; Behera, Rabindra K.; Shrout, Joshua; Theil, Elizabeth C.; Maurice, Patricia A.

    2013-01-01

    Metabolism of iron derived from insoluble and/ or scarce sources is essential for pathogenic and environmental microbes. The ability of Pseudomonas aeruginosa to acquire iron from exogenous ferritin was assessed; ferritin is an iron-concentrating and antioxidant protein complex composed of a catalytic protein and caged ferrihydrite nanomineral synthesized from Fe(II) and O2 or H2O2. Ferritin and free ferrihydrite supported growth of P. aeruginosa with indistinguishable kinetics and final culture densities. The P. aeruginosa PAO1 mutant (ΔpvdDΔpchEF), which is incapable of siderophore production, grew as well as the wild type when ferritin was the iron source. Such data suggest that P. aeruginosa can acquire iron by siderophore-independent mechanisms, including secretion of small-molecule reductant(s). Protease inhibitors abolished the growth of the siderophore-free strain on ferritins, with only a small effect on growth of the wild type; predictably, protease inhibitors had no effect on growth with free ferrihydrite as the iron source. Proteolytic activity was higher with the siderophore-free strain, suggesting that the role of proteases in the degradation of ferritin is particularly important for iron acquisition in the absence of siderophores. The combined results demonstrate the importance of both free ferrihydrite, a natural environmental form of iron and a model for an insoluble form of partly denatured ferritin called hemosiderin, and caged ferritin iron minerals as bacterial iron sources. Ferritin is also revealed as a growth promoter of opportunistic, pathogenic bacteria such a P. aeruginosa in diseased tissues such as the cystic fibrotic lung, where ferritin concentrations are abnormally high. PMID:23417538

  13. Synergistic bactericidal effects of acrinol and tetracycline against Pseudomonas aeruginosa.

    PubMed

    Saji, M; Fujii, K; Ohkuni, H; Irie, N; Osono, E; Kato, F

    2000-06-01

    Combined treatment of acrinol (Ac) and tetracycline hydrochloride (Tc) against Pseudomonas aeruginosa strains isolated from clinical specimens synergistically increased the bactericidal effect. The minimum bactericidal concentration (MBC) of Ac against P. aeruginosa strain no. 985 was 200 microg/ml, while the MBC of Ac against strains no. 47 and no. 783 was above 800 microg/ml for each. The MBC of Tc was above 400 microg/ml against each of the tested strains. However, simultaneous treatment with 25 microg/ml Ac and 200 microg/ml Tc against P. aeruginosa strain no. 985 decreased the viable cell number from 107 cfu/ml to <10 cfu/ml within 24 h, while a higher concentration of Tc (400 microg/ml) with Ac (25 microg/ml) reduced the viable cell number to <10 cfu/ml within 8 h. A similar synergistic bactericidal effect of Ac and Tc was observed in strains no. 47 and no. 783 by treatment with 200 microg/ml Ac and 200 microg/ml or 400 microg/ml Tc. The degree of bactericidal effect against P. aeruginosa was proportional to the concentration of Tc under the condition of a constant concentration of Ac. Furthermore, Ac-treated cells of strain no. 47 were killed by a following Tc treatment, but cells pretreated with Tc did not show such a sensitivity to Ac. To induce the synergistic effect of Ac and Tc, Ac must be applied to P. aeruginosa before or at the same time as Tc. PMID:11810541

  14. 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

  15. 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

  16. Effects of Chinese medicinal herbs on a rat model of chronic Pseudomonas aeruginosa lung infection.

    PubMed

    Song, Z; Johansen, H K; Moser, C; Høiby, N

    1996-05-01

    The aim of the study was to evaluate the effects of two kinds of Chinese medicinal herbs, Isatis tinctoria L (ITL) and Daphne giraldii Nitsche (DGN), on a rat model of chronic Pseudomonas aeruginosa lung infection mimicking cystic fibrosis (CF). Compared to the control group, both drugs were able to reduce the incidence of lung abscess (p < 0.05) and to decrease the severity of the macroscopic pathology in lungs (p < 0.05). In the great majority of the rats, the herbs altered the inflammatory response in the lungs from an acute type inflammation, dominated by polymorphonuclear leukocytes (PMN), to a chronic type inflammation, dominated by mononuclear leukocytes (MN). DGN also improved the clearance of P. aeruginosa from the lungs (p < 0.03) compared with the control group. There were no significant differences between the control group and the two herbal groups with regard to serum IgG and IgA anti-P. aeruginosa sonicate antibodies. However, the IgM concentration in the ITL group was significantly lower than in the control group (p < 0.03). These results suggest that the two medicinal herbs might be helpful to CF patients with chronic P. aeruginosa lung infection, DGN being the most favorable. PMID:8703440

  17. Calcium homeostasis in Pseudomonas aeruginosa requires multiple transporters and modulates swarming motility

    PubMed Central

    Guragain, Manita; Lenaburg, Dirk L.; Moore, Frank S.; Reutlinger, Ian; Patrauchan, Marianna A.

    2015-01-01

    Pseudomonas aeruginosa is an opportunistic human pathogen causing severe acute and chronic infections. Earlier we have shown that calcium (Ca2+) induces P. aeruginosa biofilm formation and production of virulence factors. To enable further studies of the regulatory role of Ca2+, we characterized Ca2+ homeostasis in P. aeruginosa PAO1 cells. By using Ca2+-binding photoprotein aequorin, we determined that the concentration of free intracellular Ca2+ ([Ca2+]in) is 0.14±0.05 μM. In response to external Ca2+, the [Ca2+]in quickly increased at least 13 fold followed by a multi-phase decline by up to 73%. Growth at elevated Ca2+ modulated this response. Treatment with inhibitors known to affect Ca2+ channels, monovalent cations gradient, or P-type and F-type ATPases impaired [Ca2+]in response, suggesting the importance of the corresponding mechanisms in Ca2+ homeostasis. To identify Ca2+ transporters maintaining this homeostasis, bioinformatic and LC-MS/MS-based membrane proteomic analyses were used. [Ca2+]in homeostasis was monitored for seven Ca2+-affected and eleven bioinformatically predicted transporters by using transposon insertion mutants. Disruption of P-type ATPases PA2435, PA3920, and ion exchanger PA2092 significantly impaired Ca2+ homeostasis. The lack of PA3920 and vanadate treatment abolished Ca2+- induced swarming, suggesting the role of the P-type ATPase in regulating P. aeruginosa response to Ca2+. PMID:24074964

  18. Ecthyma gangrenosum: a rare cutaneous manifestation caused by pseudomonas aeruginosa without bacteraemia in a leukaemic patient--a case report.

    PubMed

    Singh, T N; Devi, K M; Devi, K S

    2005-10-01

    Ecthyma gangrenosum is a rare and invasive cutaneous infection caused by Pseudomonas aeruginosa in the majority of cases, typically affecting immunocompromised patients, particularly those with neutropenia. We report a rare case of ecthyma gangrenosum in the absence of bacteraemia presenting as a solitary necrotic ulcer in a female patient with acute lymphoblastic leukaemia. A culture from the ecthyma lesion revealed the presence of Pesudomonas aeruginosa, but the results of repeated blood cultures were negative. The patient responded well to amikacin to which the isolate was susceptible in vitro. Considering high rate of mortality, early diagnosis and prompt effective treatment is mandatory. PMID:16327125

  19. Impact of quorum sensing on fitness of Pseudomonas aeruginosa.

    PubMed

    Heurlier, Karin; Dénervaud, Valérie; Haas, Dieter

    2006-04-01

    In Pseudomonas aeruginosa, cell-cell communication based on N-acyl-homoserine lactone (AHL) signal molecules (termed quorum sensing) is known to control the production of extracellular virulence factors. Hence, in pathogenic interactions with host organisms, the quorum-sensing (QS) machinery can confer a selective advantage on P. aeruginosa. However, as shown by transcriptomic and proteomic studies, many intracellular metabolic functions are also regulated by quorum sensing. Some of these serve to regenerate the AHL precursors methionine and S-adenosyl-methionine and to degrade adenosine via inosine and hypoxanthine. The fact that a significant percentage of clinical and environmental isolates of P. aeruginosa is defective for QS because of mutation in the major QS regulatory gene lasR, raises the question of whether the QS machinery can have a negative impact on the organism's fitness. In vitro, lasR mutants have a higher probability to escape lytic death in stationary phase under alkaline conditions than has the QS-proficient wild type. Similar selective forces might also operate in natural environments. PMID:16503417

  20. Genotypic analysis of Pseudomonas aeruginosa isolated from ocular infection.

    PubMed

    Yamaguchi, Satoshi; Suzuki, Takashi; Kobayashi, Takeshi; Oka, Naoko; Ishikawa, Eri; Shinomiya, Hiroto; Ohashi, Yuichi

    2014-07-01

    Pseudomonas aeruginosa is the causative pathogen of keratitis, conjunctivitis, and dacryocystitis. However little is known about their clinical epidemiology in Japan. In this study we investigated the genotypic characterization and serotype of P. aeruginosa isolates from ocular infections. Thirty-four clinical P. aeruginosa isolates were characterized according to infection type, the type III secretion system (TTSS), serotype, and multilocus sequence typing (MLST). We divided the isolates into four clinical infection types as follows: Contact lens (CL)-related keratitis (CL-keratitis; 15 isolates), non CL-related keratitis (non CL-keratitis; 8 isolates), conjunctivitis (7 isolates), and dacryocystitis (4 isolates). Regarding the TTSS classification and serotyping classification, no significant differences were found among the infection types. Two clusters (I, II) and three subclusters (A, B, C) were classified according to MLST. CL-keratitis isolates with exoU positivity were clustered in II-B, and conjunctivitis was clustered in cluster I. Some linkage was found between the genetic background and CL-keratitis or conjunctivitis. PMID:24746897

  1. Pseudomonas aeruginosa bacteriophage phi PLS27-lipopolysaccharide interactions.

    PubMed Central

    Jarrell, K F; Kropinski, A M

    1981-01-01

    We investigated the phi PLS27 receptor in Pseudomonas aeruginosa strain PAO lipopolysaccharide (LPS) by analyzing a resistant mutant. This mutant, which was designated AK1282, had the most defective LPS yet reported for a P. aeruginosa rough mutant; this LPS contained only lipid A, 2-keto-3-deoxyoctonate, heptose, and alanine as major components. In addition, this LPS lacked galactosamine, which is present in the inner core of the LPS of other rough mutants. The loss of galactosamine but only a small decrease in the alanine content indicated that the core of strain PAO LPS differed from the core structure which has been suggested for the LPS of other well-characterized P. aeruginosa strains. Our analysis also indicated that galactosamine residues may be crucial for phi PLS27 receptor activity of the LPS. Electrodialysis of LPS and conversion to salt forms (sodium or triethylamine) influenced the phage-inactivating capacity of the LPS, as did the medium in which the inactivation occurred; experiments performed in 1/10-strength broth resulted in much lower PhI50 (concentration of LPS causing a 50% decrease in the titer of phage during 1 h of incubation at 37 degrees C) values than experiments performed in regular-strength broth. Sonication of the LPS also increased the phage-inactivating capacities of the LPS preparations. PMID:6798225

  2. Nosocomial outbreak of OXA-18-producing Pseudomonas aeruginosa in Tunisia.

    PubMed

    Kalai Blagui, S; Achour, W; Abbassi, M S; Bejaoui, M; Abdeladhim, A; Ben Hassen, A

    2007-08-01

    Following systematic screening for ceftazidime-resistant (CAZ-R) Pseudomonas aeruginosa, 24 isolates producing extended-spectrum beta-lactamase (ESBL) were recovered during a 24-month period at the National Bone Marrow Transplant Centre of Tunisia. These isolates were from seven immunocompromised patients and from environmental swabs. ESBLs inhibited by clavulanic acid were detected by double-disk diffusion tests. Isoelectric focusing revealed that these isolates produced two to four beta-lactamases with pIs of 5.5, 6.1, 6.4, 7.6 or 8.2, and PCR detected the presence of bla(OXA-18), bla(SHV) and bla(TEM) genes in 24, 21 and two isolates, respectively. Pulsed-field gel electrophoresis defined two dominant genotypic groups: group A (16 isolates) and group B (four isolates). Sequencing of PCR products from representative isolates identified the bla(OXA-18) gene and revealed nucleotide sequences belonging to the bla(SHV-1) and bla(TEM-1) genes. Isolates producing OXA-18 belonged to genomic group A and were isolated from four immunocompromised patients in the haematology and graft units, and from two wash-basins in the graft unit. No immunocompromised patient harboured the clonal epidemic strain upon admission. This is the first report of the OXA-18-type ESBL in P. aeruginosa in Tunisia, and the first description of an outbreak caused by an OXA-18-producing strain of P. aeruginosa. PMID:17610599

  3. Antimicrobial activities of Saudi honey against Pseudomonas aeruginosa

    PubMed Central

    Al-Nahari, Alaa A.M.; Almasaudi, Saad B.; Abd El-Ghany, El Sayed M.; Barbour, Elie; Al Jaouni, Soad K.; Harakeh, Steve

    2015-01-01

    Five types of imported and local honey were screened for both their bacteriocidal/bacteriostatic activities against both Imipenem resistant and sensitive Pseudomonas aeruginosa in both Brain Heart infusion broth and Mueller–Hinton agar. The results indicated that the effect was concentration and type of honey dependant. All types of honey tested exerted a full inhibition of bacterial growth at the highest concentration tested of 50% at 24 h of contact. The inhibitory effect of honey on bacterial growth was clear with concentrations of 20% and 10% and this effect was most evident in the case of Manuka honey as compared to Nigella sativa honey and Seder honey. Manuka honey UMF +20 showed a bacteriocidal activity on both Imipenem resistant and sensitive P. aeruginosa, while Seder honey and N. sativa honey exerted only a bacteriostatic effect. Manuka honey UMF +10 showed most effect on antimicrobial resistance. Manuka honey UMF +10 had an effect on modulation of Imipenem resistant P. aeruginosa. Conclusion: The results indicated that various types of honey affected the test organisms differently. Modulation of antimicrobial resistance was seen in the case Manuka honey UMF +10. PMID:26288553

  4. 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

  5. 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

  6. 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

    2016-01-01

    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. PMID:27075730

  7. 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

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

    PubMed Central

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

    2016-01-01

    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. PMID:27075730

  9. 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

  10. 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

  11. 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

  12. 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. PMID:24151196

  13. Morphogenetic expression of Moraxella bovis fimbriae (pili) in Pseudomonas aeruginosa.

    PubMed Central

    Beard, M K; Mattick, J S; Moore, L J; Mott, M R; Marrs, C F; Egerton, J R

    1990-01-01

    Type 4 fimbriae (pili) are found in a wide variety of gram-negative bacteria and are composed of small structural subunits which share significant sequence homology among different species, especially at their amino-terminal ends. Previous studies demonstrating morphogenetic expression of Bacteroides nodosus fimbriae from cloned subunit genes in Pseudomonas aeruginosa suggested that there is a common mechanism for type 4 fimbriae assembly and that the structural subunits are interchangeable (J. S. Mattick et al., J. Bacteriol. 169:33-41, 1987). Here we have examined the expression of Moraxella bovis fimbrial subunits in P. aeruginosa. M. bovis subunits were assembled into extracellular fimbriae in this host, in some cases as a homopolymer but in others as a mosaic with the indigenous subunit, indicating structural equivalence. This result contrasts with other studies in which recombinant P. aeruginosa expressing different subunits produced fimbriae composed almost exclusively of one subunit or the other (T. C. Elleman and J. E. Peterson, Mol. Microbiol. 1:377-380, 1987). Both observations can be explained by reversibility of subunit-subunit interactions at the site of assembly, with the forward equilibrium favoring chain extension between compatible subunits. Images PMID:1970564

  14. 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

  15. Epidemiology of Pseudomonas aeruginosa in a tertiary referral teaching hospital.

    PubMed

    Bradbury, R S; Champion, A C; Reid, D W

    2009-10-01

    A genotypically indistinguishable strain of Pseudomonas aeruginosa (Australian epidemic strain III: AES III) has previously been found in a proportion of adults with cystic fibrosis (CF) in Tasmania, Australia. The aim of this study was to identify a source of these infections within the major tertiary referral hospital for the State of Tasmania, and to determine if this strain could be isolated from settings other than the CF lung. A total of 120 isolates of P. aeruginosa were collected from clinical and environmental sources within the hospital and from environmental locations in the hospital vicinity. These isolates were genotyped by random amplification of polymorphic DNA (RAPD)-polymerase chain reaction (PCR) and antimicrobial susceptibility testing was performed using the Clinical and Laboratory Standards Institute method. Confirmation of similar genotypes identified by RAPD-PCR was performed using pulsed-field gel electrophoresis with restriction enzyme SpeI. AES III was not recovered from any source other than the respiratory secretions of CF patients. P. aeruginosa in the non-CF settings was found to be panmictic, and no cross-infection or acquisition of hospital environment strains by patients was observed. PMID:19699556

  16. 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

  17. 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

  18. Adaptation of Iron Homeostasis Pathways by a Pseudomonas aeruginosa Pyoverdine Mutant in the Cystic Fibrosis Lung

    PubMed Central

    Nguyen, Angela T.; O'Neill, Maura J.; Watts, Annabelle M.; Robson, Cynthia L.; Lamont, Iain L.; Wilks, Angela

    2014-01-01

    Cystic fibrosis (CF) patients suffer from chronic bacterial lung infections, most notably by Pseudomonas aeruginosa, which persists for decades in the lungs and undergoes extensive evolution. P. aeruginosa requires iron for virulence and uses the fluorescent siderophore pyoverdine to scavenge and solubilize ferric iron during acute infections. Pyoverdine mutants accumulate in the lungs of some CF patients, however, suggesting that the heme and ferrous iron acquisition pathways of P. aeruginosa are more important in this environment. Here, we sought to determine how evolution of P. aeruginosa in the CF lung affects iron acquisition and regulatory pathways through the use of longitudinal CF isolates. These analyses demonstrated a significant reduction of siderophore production during the course of CF lung infection in nearly all strains tested. Mass spectrometry analysis of one of these strains showed that the later CF isolate has streamlined the metabolic flux of extracellular heme through the HemO heme oxygenase, resulting in more-efficient heme utilization. Moreover, gene expression analysis shows that iron regulation via the PrrF small RNAs (sRNAs) is enhanced in the later CF isolate. Finally, analysis of P. aeruginosa gene expression in the lungs of various CF patients demonstrates that both PrrF and HemO are consistently expressed in the CF lung environment. Combined, these results suggest that heme is a critical source of iron during prolonged infection of the CF lung and that changes in iron and heme regulatory pathways play a crucial role in adaptation of P. aeruginosa to this ever-changing host environment. PMID:24727222

  19. Adaptation of iron homeostasis pathways by a Pseudomonas aeruginosa pyoverdine mutant in the cystic fibrosis lung.

    PubMed

    Nguyen, Angela T; O'Neill, Maura J; Watts, Annabelle M; Robson, Cynthia L; Lamont, Iain L; Wilks, Angela; Oglesby-Sherrouse, Amanda G

    2014-06-01

    Cystic fibrosis (CF) patients suffer from chronic bacterial lung infections, most notably by Pseudomonas aeruginosa, which persists for decades in the lungs and undergoes extensive evolution. P. aeruginosa requires iron for virulence and uses the fluorescent siderophore pyoverdine to scavenge and solubilize ferric iron during acute infections. Pyoverdine mutants accumulate in the lungs of some CF patients, however, suggesting that the heme and ferrous iron acquisition pathways of P. aeruginosa are more important in this environment. Here, we sought to determine how evolution of P. aeruginosa in the CF lung affects iron acquisition and regulatory pathways through the use of longitudinal CF isolates. These analyses demonstrated a significant reduction of siderophore production during the course of CF lung infection in nearly all strains tested. Mass spectrometry analysis of one of these strains showed that the later CF isolate has streamlined the metabolic flux of extracellular heme through the HemO heme oxygenase, resulting in more-efficient heme utilization. Moreover, gene expression analysis shows that iron regulation via the PrrF small RNAs (sRNAs) is enhanced in the later CF isolate. Finally, analysis of P. aeruginosa gene expression in the lungs of various CF patients demonstrates that both PrrF and HemO are consistently expressed in the CF lung environment. Combined, these results suggest that heme is a critical source of iron during prolonged infection of the CF lung and that changes in iron and heme regulatory pathways play a crucial role in adaptation of P. aeruginosa to this ever-changing host environment. PMID:24727222

  20. Phase II studies of nebulised Arikace in CF patients with Pseudomonas aeruginosa infection

    PubMed Central

    Clancy, J P; Dupont, L; Konstan, M W; Billings, J; Fustik, S; Goss, C H; Lymp, J; Minic, P; Quittner, A L; Rubenstein, R C; Young, K R; Saiman, L; Burns, J L; Govan, J R W; Ramsey, B; Gupta, R

    2013-01-01

    Rationale Arikace is a liposomal amikacin preparation for aerosol delivery with potent Pseudomonas aeruginosa killing and prolonged lung deposition. Objectives To examine the safety and efficacy of 28 days of once-daily Arikace in cystic fibrosis (CF) patients chronically infected with P aeruginosa. Methods 105 subjects were evaluated in double-blind, placebo-controlled studies. Subjects were randomised to once-daily Arikace (70, 140, 280 and 560 mg; n=7, 5, 21 and 36 subjects) or placebo (n=36) for 28 days. Primary outcomes included safety and tolerability. Secondary outcomes included lung function (forced expiratory volume at one second (FEV1)), P aeruginosa density in sputum, and the Cystic Fibrosis Quality of Life Questionnaire—Revised (CFQ-R). Results The adverse event profile was similar among Arikace and placebo subjects. The relative change in FEV1 was higher in the 560 mg dose group at day 28 (p=0.033) and at day 56 (28 days post-treatment, 0.093L±0.203 vs −0.032L±0.119; p=0.003) versus placebo. Sputum P aeruginosa density decreased >1 log in the 560 mg group versus placebo (days 14, 28 and 35; p=0.021). The Respiratory Domain of the CFQ-R increased by the Minimal Clinically Important Difference (MCID) in 67% of Arikace subjects (560 mg) versus 36% of placebo (p=0.006), and correlated with FEV1 improvements at days 14, 28 and 42 (p<0.05). An open-label extension (560 mg Arikace) for 28 days followed by 56 days off over six cycles confirmed durable improvements in lung function and sputum P aeruginosa density (n=49). Conclusions Once-daily Arikace demonstrated acute tolerability, safety, biologic activity and efficacy in patients with CF with P aeruginosa infection. PMID:23749840

  1. 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. PMID:27249962

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

    PubMed

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

    2016-04-01

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

  3. Efficacy of methanolic extract of green and black teas against extended-spectrum β-Lactamase-producing Pseudomonas aeruginosa.

    PubMed

    Taherpour, Arezou; Hashemi, Ali; Erfanimanesh, Soroor; Taki, Elahe

    2016-07-01

    Pseudomonas aeruginosa is one of the major bacteria causing acute infections. β-Lactamase production is the principal defense mechanism in gram-negative bacteria. The aim of our study was to evaluate the antibacterial activity of Methanolic Extracts of Green and Black Teas on P. aeruginosa Extended Spectrum-β-Lactamases (ESBLs) production. This research was carried out on burn wounds of 245 hospitalized patients in Kerman, Iran. P. aeruginosa ESBLs and MBL producing strains were detected by Combination Disk Diffusion Test (CDDT) and Epsilometer test (E-test) strips, respectively. Minimum inhibitory concentration (MIC) was measured for Ceftazidime, Meropenem, Imipenem, Aztreonam, Cefotaxime and methanollic extracts of Camellia Sinensis (Green Tea). From 245 patients in the burn ward, 120 cases were infected with P. aeruginosa. 41 isolates contained ESBL while MBL was not detected. P. aeruginosa were resistant to Cefotaxime, Aztreonam, Ceftazidime, Meropenem and Imipenem, 72 (60%), 50 (41.66%), 79 (65.83%), 33 (27.5%) and 24 (20%), respectively. Green tea extract had the highest anti-bacterial effect on standard and P. aeruginosa strains in 1.25mg/ml concentration. This study determined that the methanolic extract of green tea has a higher effect against ESBL producing P. aeruginosa than Cefotaxime, Aztreonam and Ceftazidime. PMID:27393439

  4. Pathogen Special: Vibrio Cholerae, Pseudomonas Aeruginosa and Xylella Fastidiosa

    PubMed Central

    2000-01-01

    One could almost say that it is the latest fashion to sequence a bacterial genome. However, this would belittle the efforts of those working on these important organisms, whose data will greatly help those working on the prevention of disease in the fields of medicine and agriculture. In this feature we present a guided tour of the latest additions to the ‘sequenced microbes’ club. Vibrio cholerae is the causative agent of cholera, which is still a threat in countries with poor sanitation and unsafe drinking water. Pseudomonas aeruginosa is responsible for a large proportion of opportunistic human infections, typically infecting those with compromised immune systems, particularly cystic fibrosis patients, those patients on respirators and burn victims. Xylella fastidiosa is a plant pathogen that attacks citrus fruits by blocking the xylem, resulting in juiceless fruits of no commercial value. PMID:11119308

  5. 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

  6. Bioengineered lysozyme in combination therapies for Pseudomonas aeruginosa lung infections.

    PubMed

    Griswold, Karl E; Bement, Jenna L; Teneback, Charlotte C; Scanlon, Thomas C; Wargo, Matthew J; Leclair, Laurie W

    2014-01-01

    There is increasing urgency in the battle against drug-resistant bacterial pathogens, and this public health crisis has created a desperate need for novel antimicrobial agents. Recombinant human lysozyme represents one interesting candidate for treating pulmonary infections, but the wild type enzyme is subject to electrostatic mediated inhibition by anionic biopolymers that accumulate in the infected lung. We have redesigned lysozyme's electrostatic potential field, creating a genetically engineered variant that is less susceptible to polyanion inhibition, yet retains potent bactericidal activity. A recent publication demonstrated that the engineered enzyme outperforms wild type lysozyme in a murine model of Pseudomonas aeruginosa lung infection. Here, we expand upon our initial studies and consider dual therapies that combine lysozymes with an antimicrobial peptide. Consistent with our earlier results, the charge modified lysozyme combination outperformed its wild type counterpart, yielding more than an order-of-magnitude reduction in bacterial burden following treatment with a single dose. PMID:24637705

  7. Quinoprotein alcohol dehydrogenase from ethanol-grown Pseudomonas aeruginosa.

    PubMed Central

    Groen, B; Frank, J; Duine, J A

    1984-01-01

    Cell-free extracts of Pseudomonas aeruginosa strains, grown on ethanol, showed dye-linked alcohol dehydrogenase activities. The enzyme responsible for this activity was purified to homogeneity. It appeared to contain two molecules of pyrroloquinoline quinone per enzyme molecule. In many respects, it resembled other quinoprotein alcohol dehydrogenases (EC 1.1.99.8), having a substrate specificity intermediate between that of methanol dehydrogenases and ethanol dehydrogenases in this group. On the other hand, it also showed dissimilarities: the enzyme was found to be a monomer (Mr 101 000), to need only one molecule of the suicide substrate cyclopropanol to become fully inactivated, and to have a different aromatic amino acid composition. PMID:6439190

  8. Heat shock mediated labelling of Pseudomonas aeruginosa with quantum dots.

    PubMed

    Kumar, Natasha; Wiraja, Christian; Palanisamy, Kannan; Marsili, Enrico; Xu, Chenjie

    2016-06-01

    Biocompatible nanoparticles are good candidates to label bacteria for imaging and diagnosis purposes. A high labeling efficiency reduces the concentration of nanoparticles required for labeling and allows the labeled bacteria to be tracked for longer periods. This report explores the optimal labeling strategy for Pseudomonas aeruginosa, a common gram-negative opportunistic pathogen, with quantum dots. Three strategies including direct incubation, calcium chloride treatment, and heat shock are compared and the labeling efficiency is assessed through fluorescence microscopy and flow cytometry analysis. Of the three, heat shock is finally selected due to its comparable labeling efficiency and simplicity. Through the assay of the respiration rate of bacteria together with morphology analysis, the heat shock process does not show any negative effect over the cells activity even at sub-toxic concentrations. PMID:26962762

  9. Characterization of Pseudomonas aeruginosa mutants with altered piliation.

    PubMed Central

    Johnson, K; Lory, S

    1987-01-01

    The pilus-specific Pseudomonas aeruginosa bacteriophage P04 was used to select spontaneous mutants of strain PAK which have altered piliation. The largest class of phage-resistant mutants synthesized the pilin polypeptide, but did not assemble pili. These mutants are likely to contain mutations in genes required for pilus assembly and not mutations in the pilin structural gene, as they could not be complemented by a normal copy of the pilin gene. In addition, two alterations in pilin gene transcription were found among the mutants--hyperpiliated mutants which overproduce pilin mRNA, and a mutant with temperature-sensitive pilin gene transcription. We also present a model for the regulation of pilin gene transcription by a feedback mechanism sensitive to the relative rates of pilus assembly and disassembly. Images PMID:2445731

  10. Amino Acid-β-Naphthylamide Hydrolysis by Pseudomonas aeruginosa Arylamidase

    PubMed Central

    Riley, P. S.; Behal, Francis J.

    1971-01-01

    The intracellular and constitutive arylamidase from Pseudomonas aeruginosa was purified 528-fold by salt fractionation, ion-exchange chromatography, gel filtration, and adsorption chromatography. This enzyme hydrolyzed basic and neutral N-terminal amino acid residues from amino-β-naphthylamides, dipeptide-β-naphthylamides, and a variety of polypeptides. Only those substrates having an l-amino acid with an unsubstituted α-amino group as the N-terminal residue were susceptible to enzymatic hydrolysis. The molecular weight was estimated to be 71,000 daltons. The lowest Km values were associated with substrates having neutral or basic amino acid residues with large side chains with no substitution or branching on the β carbon atom. Images PMID:5001871

  11. 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

  12. Pseudomonas Aeruginosa Resistance Phenotypes and Phenotypic Highlighting Methods

    PubMed Central

    BĂLĂŞOIU, MARIA; BĂLĂŞOIU, A.T.; MĂNESCU, RODICA; AVRAMESCU, CARMEN; IONETE, OANA

    2014-01-01

    Pseudomonas aeruginosa genus bacteria are well known for their increased drug resistance (phenotypic ang genotypic resistance). The most important resistance mechanisms are: enzyme production, reduction of pore expression, reduction of the external membrane proteins expression, efflux systems, topoisomerase mutations. These mechanisms often accumulate and lead to multidrug ressitance strains emergence. The most frequent acquired resistance mechanisms are betalactamase-type enzyme production (ESBLs, AmpC, carbapenemases), which determine variable phenotypes of betalactamines resistance, phenotypes which are associated with aminoglycosides and quinolones resistance. The nonenzymatic drug resistance mechanisms are caused by efflux systems, pore reduction and penicillin-binding proteins (PBP) modification, which are often associated to other resistance mechanisms. Phenotypic methods used for testing these mechanisms are based on highlighting these phenotypes using Kirby Bauer antibiogram, clinical breakpoints, and “cut off” values recommended by EUCAST 2013 standard, version 3.1. PMID:25729587

  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. Type IV pili interactions promote intercellular association and moderate swarming of Pseudomonas aeruginosa.

    PubMed

    Anyan, Morgen E; Amiri, Aboutaleb; Harvey, Cameron W; Tierra, Giordano; Morales-Soto, Nydia; Driscoll, Callan M; Alber, Mark S; Shrout, Joshua D

    2014-12-16

    Pseudomonas aeruginosa is a ubiquitous bacterium that survives in many environments, including as an acute and chronic pathogen in humans. Substantial evidence shows that P. aeruginosa behavior is affected by its motility, and appendages known as flagella and type IV pili (TFP) are known to confer such motility. The role these appendages play when not facilitating motility or attachment, however, is unclear. Here we discern a passive intercellular role of TFP during flagellar-mediated swarming of P. aeruginosa that does not require TFP extension or retraction. We studied swarming at the cellular level using a combination of laboratory experiments and computational simulations to explain the resultant patterns of cells imaged from in vitro swarms. Namely, we used a computational model to simulate swarming and to probe for individual cell behavior that cannot currently be otherwise measured. Our simulations showed that TFP of swarming P. aeruginosa should be distributed all over the cell and that TFP-TFP interactions between cells should be a dominant mechanism that promotes cell-cell interaction, limits lone cell movement, and slows swarm expansion. This predicted physical mechanism involving TFP was confirmed in vitro using pairwise mixtures of strains with and without TFP where cells without TFP separate from cells with TFP. While TFP slow swarm expansion, we show in vitro that TFP help alter collective motion to avoid toxic compounds such as the antibiotic carbenicillin. Thus, TFP physically affect P. aeruginosa swarming by actively promoting cell-cell association and directional collective motion within motile groups to aid their survival. PMID:25468980

  15. Resistance of Pseudomonas aeruginosa Isolates to Hydrogel Contact Lens Disinfection Correlates with Cytotoxic Activity

    PubMed Central

    Lakkis, Carol; Fleiszig, Suzanne M. J.

    2001-01-01

    One of the most common pathogens in infection of hydrogel contact lens wearers is Pseudomonas aeruginosa, which can gain access to the eye via contamination of the lens, lens case, and lens care solutions. Only one strain per species is used in current regulatory testing for the marketing of chemical contact lens disinfectants. The aim of this study was to determine whether P. aeruginosa strains vary in their susceptibility to hydrogel contact lens disinfectants. A method for rapidly screening bacterial susceptibility to contact lens disinfectants was developed, based on measurement of the MIC. The susceptibility of 35 P. aeruginosa isolates to two chemical disinfectants was found to vary among strains. MICs ranged from 6.25 to 100% for both disinfectants at 37°C, and a number of strains were not inhibited by a 100% disinfectant concentration in the lens case environment at room temperature (22°C). Resistance to disinfection appeared to be an inherent rather than acquired trait, since some resistant strains had been isolated prior to the introduction of the disinfectants and some susceptible P. aeruginosa strains could not be made more resistant by repeated disinfectant exposure. A number of P. aeruginosa strains which were comparatively more resistant to short-term disinfectant exposure also demonstrated the ability to grow to levels above the initial inoculum in one chemical disinfectant after long-term (24 to 48 h) disinfectant exposure. Resistance was correlated with acute cytotoxic activity toward corneal epithelial cells and with exsA, which encodes a protein that regulates cytotoxicity via a complex type III secretion system. These results suggest that chemical disinfection solutions may select for contamination with cytotoxic strains. Further investigation of the mechanisms and factors responsible for resistance may also lead to strategies for reducing adverse responses to contact lens wear. PMID:11283074

  16. Type IV pili interactions promote intercellular association and moderate swarming of Pseudomonas aeruginosa

    PubMed Central

    Anyan, Morgen E.; Amiri, Aboutaleb; Harvey, Cameron W.; Tierra, Giordano; Morales-Soto, Nydia; Driscoll, Callan M.; Alber, Mark S.; Shrout, Joshua D.

    2014-01-01

    Pseudomonas aeruginosa is a ubiquitous bacterium that survives in many environments, including as an acute and chronic pathogen in humans. Substantial evidence shows that P. aeruginosa behavior is affected by its motility, and appendages known as flagella and type IV pili (TFP) are known to confer such motility. The role these appendages play when not facilitating motility or attachment, however, is unclear. Here we discern a passive intercellular role of TFP during flagellar-mediated swarming of P. aeruginosa that does not require TFP extension or retraction. We studied swarming at the cellular level using a combination of laboratory experiments and computational simulations to explain the resultant patterns of cells imaged from in vitro swarms. Namely, we used a computational model to simulate swarming and to probe for individual cell behavior that cannot currently be otherwise measured. Our simulations showed that TFP of swarming P. aeruginosa should be distributed all over the cell and that TFP−TFP interactions between cells should be a dominant mechanism that promotes cell−cell interaction, limits lone cell movement, and slows swarm expansion. This predicted physical mechanism involving TFP was confirmed in vitro using pairwise mixtures of strains with and without TFP where cells without TFP separate from cells with TFP. While TFP slow swarm expansion, we show in vitro that TFP help alter collective motion to avoid toxic compounds such as the antibiotic carbenicillin. Thus, TFP physically affect P. aeruginosa swarming by actively promoting cell−cell association and directional collective motion within motile groups to aid their survival. PMID:25468980

  17. The transcriptional regulator AlgR is essential for Pseudomonas aeruginosa pathogenesis.

    PubMed

    Lizewski, Stephen E; Lundberg, Derek S; Schurr, Michael J

    2002-11-01

    Chronic Pseudomonas aeruginosa lung infection is the major cause of morbidity and mortality in cystic fibrosis (CF) patients. One P. aeruginosa virulence factor unique to CF isolates is overproduction of alginate, phenotypically termed mucoidy. Mucoidy is the result of increased transcription from the algD gene and is activated by the transcriptional regulator AlgR. Mutations in algR result in a nonmucoid phenotype and loss of twitching motility. Additionally, AlgR controls transcription of algC, encoding a dual-function enzyme necessary for both lipopolysaccharide (LPS) and alginate production. Therefore, to determine the effect of algR on P. aeruginosa virulence, an algR mutant was examined for sensitivity to reactive oxygen intermediates, killing by phagocytes, systemic virulence, and the ability to maintain a murine lung infection. We found that P. aeruginosa PAO700 (algR::Gm(r)) was less lethal than PAO1, as tested in an acute septicemia infection mouse model, and was cleared more efficiently in a mouse pneumonia model. Additionally, the algR mutant (PAO700) was more sensitive to hypochlorite. However, PAO700 was more resistant to hydrogen peroxide and killed less readily in an acellular myeloperoxidase assay than PAO1. There was little difference in killing between PAO1 and PAO700 with macrophage-like J774 cells and human polymorhonuclear leukocytes. Two-dimensional gel analysis of P. aeruginosa algR mutant and wild-type protein extracts revealed 47 differentially regulated proteins, suggesting that AlgR plays both a positive role and a negative role in gene expression. Together, these results imply that AlgR is necessary for virulence and regulates genes in addition to the genes associated with alginate and LPS production and pilus function. PMID:12379685

  18. Genes Required for and Effects of Alginate Overproduction Induced by Growth of Pseudomonas aeruginosa on Pseudomonas Isolation Agar Supplemented with Ammonium Metavanadate

    PubMed Central

    Damron, F. Heath; Barbier, Mariette; McKenney, Elizabeth S.; Schurr, Michael J.

    2013-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that can adapt to changing environments and can secrete an exopolysaccharide known as alginate as a protection response, resulting in a colony morphology and phenotype referred to as mucoid. However, how P. aeruginosa senses its environment and activates alginate overproduction is not fully understood. Previously, we showed that Pseudomonas isolation agar supplemented with ammonium metavanadate (PIAAMV) induces P. aeruginosa to overproduce alginate. Vanadate is a phosphate mimic and causes protein misfolding by disruption of disulfide bonds. Here we used PIAAMV to characterize the pathways involved in inducible alginate production and tested the global effects of P. aeruginosa growth on PIAAMV by a mutant library screen, by transcriptomics, and in a murine acute virulence model. The PA14 nonredundant mutant library was screened on PIAAMV to identify new genes that are required for the inducible alginate stress response. A functionally diverse set of genes encoding products involved in cell envelope biogenesis, peptidoglycan remodeling, uptake of phosphate and iron, phenazine biosynthesis, and other processes were identified as positive regulators of the mucoid phenotype on PIAAMV. Transcriptome analysis of P. aeruginosa cultures growing in the presence of vanadate showed differential expression of genes involved in virulence, envelope biogenesis, and cell stress pathways. In this study, it was observed that growth on PIAAMV attenuates P. aeruginosa in a mouse pneumonia model. Induction of alginate overproduction occurs as a stress response to protect P. aeruginosa, but it may be possible to modulate and inhibit these pathways based on the new genes identified in this study. PMID:23794622

  19. Purification and properties of two deoxyribonucleases of Pseudomonas aeruginosa.

    PubMed Central

    Miller, R V; Clark, A J

    1976-01-01

    A survey of the major deoxyribonucleases in Pseudomonas aeruginosa strain PAO was undertaken. Two activities predominated in Brij-58 lysates of this organism. These have been purified from contaminating nuclease activities, and some of their properties have been elucidated. The first was a nuclease that degraded heat-denatured deoxyribonucleic acid (DNA) to mono- and dinucleotides. The activity of this enzyme was confined to single-stranded DNA, and 100% of the substrate was hydrolyzed to acid-soluble material. The Mg2+ optimum is low (1 to 3mM), and the molecular weight is 6 X 10(4). The second predominant activity was an adenosine 5'-triphosphate (ATP)-dependent deoxyribonuclease. This enzyme had an absolute dependence on the presence of ATP Mg2+ concentrations of approximately 10 mM. Five moles of ATP was consumed for each mole of phosphodiester bonds cleaved. The acid-soluble products of the reaction consisted of short oligonucleotides from one to six bases in length. Only 50% of the double-stranded DNA was rendered acid soluble in a limit digest. The molecular weight of this enzyme is 3 X 10(5). The observation of these enzymes in P. aeruginosa is consistent with the possibility that recombinational pathways similar to those of Escherichia coli are operating in this organism. PMID:60331

  20. 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.

  1. 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

  2. Denitrification by Pseudomonas Aeruginosa Under Simulated Engineered Martain Conditions

    NASA Astrophysics Data System (ADS)

    Hart, S. D.; Currier, P. A.; Thomas, D. J.

    The growth of Pseudomonas aeruginosa in denitrifying medium was observed for 14 days in the presence of a martian soil analog (JSC Mars-1) and elevated CO2 levels. A four-way test was conducted comparing growth of experimental samples to growth in the presence of inert silica (“Earth soil”) and normal terrestrial atmosphere. The combination of 50 mL of fluorescence-denitrification medium and 10 grams of soil additive simulated an aquatic environment, which was contained in sealed culture bottles. Nitrite assays of the media (to test for consumption during denitrification), gas sampling from the bottles to observe nitrogen production, and colony counts to quantify growth rate were all performed at 0, 7 and 14 days after inoculation. Supplemental tests performed included nitrate assays (to confirm the occurrence of denitrification) and culture fluorescence (as a non-invasive growth test). Growth and denitrification took place under all conditions, and no significant differ- ences were observed between samples. These data indicate that the presence of simulated martian regolith and elevated CO2 have little or no effect on the growth of or denitrification by P. aeruginosa at the concentrations used.

  3. 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

  4. 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

  5. Pseudomonas aeruginosa Exopolyphosphatase Is Also a Polyphosphate: ADP Phosphotransferase

    PubMed Central

    Beassoni, Paola R.; Gallarato, Lucas A.; Boetsch, Cristhian; Garrido, Mónica N.; Lisa, Angela T.

    2015-01-01

    Pseudomonas aeruginosa exopolyphosphatase (paPpx; EC 3.6.1.11) catalyzes the hydrolysis of polyphosphates (polyP), producing polyPn−1 plus inorganic phosphate (Pi). In a recent work we have shown that paPpx is involved in the pathogenesis of P. aeruginosa. The present study was aimed at performing the biochemical characterization of this enzyme. We found some properties that were already described for E. coli Ppx (ecPpx) but we also discovered new and original characteristics of paPpx: (i) the peptide that connects subdomains II and III is essential for enzyme activity; (ii) NH4+ is an activator of the enzyme and may function at concentrations lower than those of K+; (iii) Zn2+ is also an activator of paPpx and may substitute Mg2+ in the catalytic site; and (iv) paPpx also has phosphotransferase activity, dependent on Mg2+ and capable of producing ATP regardless of the presence or absence of K+ or NH4+ ions. In addition, we detected that the active site responsible for the phosphatase activity is also responsible for the phosphotransferase activity. Through the combination of molecular modeling and docking techniques, we propose a model of the paPpx N-terminal domain in complex with a polyP chain of 7 residues long and a molecule of ADP to explain the phosphotransferase activity. PMID:26576296

  6. Carbapenem Resistance Mechanisms in Pseudomonas aeruginosa Clinical Isolates

    PubMed Central

    Pai, Hyunjoo; Kim, Jong-Won; Kim, Jungmin; Lee, Ji Hyang; Choe, Kang Won; Gotoh, Naomasa

    2001-01-01

    In order to define the contributions of the mechanisms for carbapenem resistance in clinical strains of Pseudomonas aeruginosa, we investigated the presence of OprD, the expressions of the MexAB-OprM and MexEF-OprN systems, and the production of the β-lactamases for 44 clinical strains. All of the carbapenem-resistant isolates showed the loss of or decreased levels of OprD. Three strains overexpressed the MexAB-OprM efflux system by carrying mutations in mexR. These three strains had the amino acid substitution in MexR protein, Arg (CGG) → Gln (CAG), at the position of amino acid 70. None of the isolates, however, expressed the MexEF-OprN efflux system. For the characterization of β-lactamases, at least 13 isolates were the depressed mutants, and 12 strains produced secondary β-lactamases. Based on the above resistance mechanisms, the MICs of carbapenem for the isolates were analyzed. The MICs of carbapenem were mostly determined by the expression of OprD. The MICs of meropenem were two- to four-fold increased for the isolates which overexpressed MexAB-OprM in the background of OprD loss. However, the elevated MICs of meropenem for some individual isolates could not be explained. These findings suggested that other resistance mechanisms would play a role in meropenem resistance in clinical isolates of P. aeruginosa. PMID:11158744

  7. Genes related to chromate resistance by Pseudomonas aeruginosa PAO1.

    PubMed

    Rivera, Sonia L; Vargas, Eréndira; Ramírez-Díaz, Martha I; Campos-García, Jesús; Cervantes, Carlos

    2008-08-01

    Chromate-hypersensitive mutants of the Pseudomonas aeruginosa PAO1 strain were isolated using transposon-insertion mutagenesis. Comparison of the nucleotide sequences of the regions interrupted in the mutants with the PAO1 genome revealed that the genes affected in three mutant strains were oprE (ORF PA0291), rmlA (ORF PA5163), and ftsK (ORF PA2615), respectively. A relationship of these genes with chromate tolerance has not been previously reported. No other phenotypic changes were observed in the oprE mutant but its resistance to chromate was not fully restored by expressing the ChrA protein, which extrudes chromate ions from the cytoplasm to the periplasmic space. These data suggest that OprE participates in the efflux of chromate from the periplasm to the outside. Increased susceptibility of the rmlA mutant to the metals cadmium and mercury and to the anion-superoxide generator paraquat suggests a protective role of LPS against chromate toxicity. A higher susceptibility of the ftsK mutant to compounds affecting DNA structure (ciprofloxacin, tellurite, mitomycin C) suggests a role of FtsK in the recombinational repair of DNA damage caused by chromate. In conclusion, the P. aeruginosa genome contains diverse genes related to its intrinsic resistance to chromate. Systems pertaining to the outer membrane (OprE), the cell wall (LPS), and the cytoplasm (FtsK) were identified in this work as involved in chromate protection mechanisms. PMID:18446454

  8. 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

  9. 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

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

    PubMed Central

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

    2015-01-01

    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. PMID:26041805

  11. [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

  12. Pseudomonas aeruginosa: my research passion. Interview by Hannah Branch.

    PubMed

    Hazlett, Linda

    2013-07-01

    Linda Hazlett is a department chair and distinguished professor at Wayne State University (MI, USA). Her research is focused on the host immune response to Pseudomonas aeruginosa and its role in ocular infections. Dr Hazlett has been funded continuously by the NIH by R01 support for 34 years. She is currently principal investigator of two R01 grants from the National Eye Institute that study pathogenesis of P. aeruginosa in the eye. Dr Hazlett oversees four Course Directors who lead Year 1 medical student teaching, in addition to two graduate course directors. Furthermore, although not involved in medical teaching, she educates graduate students and mentors a Research Scientist and a Research Assistant Professor. Throughout her career, Dr Hazlett has achieved several honors and awards including Distinguished Professor at Wayne State University (2008), National Eye Institute Core Center (P30) grant for 1987-2013, Chair of Physiology Search 2008-2009, Member of the Academy of Scholars at Wayne State University, Association for Research in Vision and Ophthalmology fellow at the Gold Medal level (2009) and was an invited speaker at the Gordon Conference 2010. PMID:23841630

  13. 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

  14. 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

  15. Pseudomonas aeruginosa outer membrane adhesins for human respiratory mucus glycoproteins.

    PubMed Central

    Carnoy, C; Scharfman, A; Van Brussel, E; Lamblin, G; Ramphal, R; Roussel, P

    1994-01-01

    The attachment of Pseudomonas aeruginosa to human respiratory mucus represents an important step in the development of lung infection, especially in cases of cystic fibrosis. For this purpose, microtiter plate adhesion assays have been developed and have suggested that nonpilus adhesins of P. aeruginosa are the most important ones for binding to human respiratory mucins. In order to characterize these mucin-binding adhesins, outer membrane proteins (OMP) from two adhesive strains, 1244-NP and PAK-NP, and their poorly adhesive rpoN mutants, 1244-N3 and PAK-N1, were prepared by a mild extraction with Zwittergent 3-14. Mucin-binding adhesins were detected after polyacrylamide gel electrophoresis and blotting of the OMP on nitrocellulose replicas, using human bronchial mucins labeled with 125I. The binding properties of these OMP with lactotransferrin, another glycoprotein abundant in respiratory mucus, were also studied. Radiolabeled mucins detected four bands at 48, 46, 28, and 25 kDa with strain PAK-NP. With the nonmucoid strain 1244-NP, five bands were observed at 48, 46, 42, 28, and 25 kDa. The bands at 48 and 25 kDa were also visualized by radiolabeled lactotransferrin. These bands were partially or completely displaced by nonradiolabeled respiratory mucin glycopeptides but not by tetramethylurea, suggesting that they recognized carbohydrate sites. In contrast, the poorly adhesive strains showed weakly binding bands. These results demonstrate that outer membranes from two different nonpiliated P. aeruginosa strains express multiple adhesins with an affinity for human respiratory mucins and/or lactotransferrin. Images PMID:8168955

  16. Transcriptional analysis of the Pseudomonas aeruginosa exoenzyme S structural gene.

    PubMed Central

    Yahr, T L; Hovey, A K; Kulich, S M; Frank, D W

    1995-01-01

    The transcriptional regulation of the Pseudomonas aeruginosa exoS gene was investigated. Expression of exoS in P. aeruginosa PA103 was dependent upon growth in a low-cation environment and the presence of a functional exsA gene. Promoter fusion analysis indicated that a 285-bp PstI-NsiI fragment, located 5' of the exoS coding region, contained a functional promoter for exoS. Expression of the reporter gene was inducible in a low-cation growth environment and required a functional copy of exsA. Divergent promoters, coordinately regulated with exoS transcription, were identified within the PstI-NsiI fragment. A fusion derivative of ExsA, MALA3A2, was shown to bind directly to the PstI-NsiI probe. DNase I protection analysis demonstrated that MALA3A2 bound to the intergenic region between the postulated -35 boxes of each promoter region. Northern (RNA) blot analysis with probes internal to and upstream of exoS demonstrated that separate, coordinately regulated mRNAs were expressed in P. aeruginosa. These data suggested that a locus, coregulated with exoS transcription, was located upstream of exoS. DNA sequence analysis of the exoS upstream region revealed three open reading frames, ORF 1, ORF 2, and ORF 3. ORF 1 demonstrated significant homology to the SycE/YerA protein of Yersinia sp. SycE/YerA is postulated to function as a chaperone for the YopE cytotoxin. The loci encoding YopE and ExoS show similarities in genetic organization, protein composition, and regulation. PMID:7868588

  17. 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

  18. Pseudomonas aeruginosa EftM Is a Thermoregulated Methyltransferase.

    PubMed

    Owings, Joshua P; Kuiper, Emily G; Prezioso, Samantha M; Meisner, Jeffrey; Varga, John J; Zelinskaya, Natalia; Dammer, Eric B; Duong, Duc M; Seyfried, Nicholas T; Albertí, Sebastián; Conn, Graeme L; Goldberg, Joanna B

    2016-02-12

    Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that trimethylates elongation factor-thermo-unstable (EF-Tu) on lysine 5. Lysine 5 methylation occurs in a temperature-dependent manner and is generally only seen when P. aeruginosa is grown at temperatures close to ambient (25 °C) but not at higher temperatures (37 °C). We have previously identified the gene, eftM (for EF-Tu-modifying enzyme), responsible for this modification and shown its activity to be associated with increased bacterial adhesion to and invasion of respiratory epithelial cells. Bioinformatic analyses predicted EftM to be a Class I S-adenosyl-l-methionine (SAM)-dependent methyltransferase. An in vitro methyltransferase assay was employed to show that, in the presence of SAM, EftM directly trimethylates EF-Tu. A natural variant of EftM, with a glycine to arginine substitution at position 50 in the predicted SAM-binding domain, lacks both SAM binding and enzyme activity. Mass spectrometry analysis of the in vitro methyltransferase reaction products revealed that EftM exclusively methylates at lysine 5 of EF-Tu in a distributive manner. Consistent with the in vivo temperature dependence of methylation of EF-Tu, preincubation of EftM at 37 °C abolished methyltransferase activity, whereas this activity was retained when EftM was preincubated at 25 °C. Irreversible protein unfolding at 37 °C was observed, and we propose that this instability is the molecular basis for the temperature dependence of EftM activity. Collectively, our results show that EftM is a thermolabile, SAM-dependent methyltransferase that directly trimethylates lysine 5 of EF-Tu in P. aeruginosa. PMID:26677219

  19. Biotic inactivation of the Pseudomonas aeruginosa quinolone signal molecule.

    PubMed

    Soh, Eliza Ye-Chen; Chhabra, Siri R; Halliday, Nigel; Heeb, Stephan; Müller, Christine; Birmes, Franziska S; Fetzner, Susanne; Cámara, Miguel; Chan, Kok-Gan; Williams, Paul

    2015-11-01

    In Pseudomonas aeruginosa, quorum sensing (QS) regulates the production of secondary metabolites, many of which are antimicrobials that impact on polymicrobial community composition. Consequently, quenching QS modulates the environmental impact of P. aeruginosa. To identify bacteria capable of inactivating the QS signal molecule 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS), a minimal medium containing PQS as the sole carbon source was used to enrich a Malaysian rainforest soil sample. This yielded an Achromobacter xylosoxidans strain (Q19) that inactivated PQS, yielding a new fluorescent compound (I-PQS) confirmed as PQS-derived using deuterated PQS. The I-PQS structure was elucidated using mass spectrometry and nuclear magnetic resonance spectroscopy as 2-heptyl-2-hydroxy-1,2-dihydroquinoline-3,4-dione (HHQD). Achromobacter xylosoxidans Q19 oxidized PQS congeners with alkyl chains ranging from C1 to C5 and also N-methyl PQS, yielding the corresponding 2-hydroxy-1,2-dihydroquinoline-3,4-diones, but was unable to inactivate the PQS precursor HHQ. This indicates that the hydroxyl group at position 3 in PQS is essential and that A. xylosoxidans inactivates PQS via a pathway involving the incorporation of oxygen at C2 of the heterocyclic ring. The conversion of PQS to HHQD also occurred on incubation with 12/17 A. xylosoxidans strains recovered from cystic fibrosis patients, with P. aeruginosa and with Arthrobacter, suggesting that formation of hydroxylated PQS may be a common mechanism of inactivation. PMID:25809238

  20. X-ray Irradiated Vaccine Confers protection against Pneumonia caused by Pseudomonas Aeruginosa

    PubMed Central

    Li, Yanyan; Wang, Zhenling; Liu, Xiaoxiao; Tang, Jianying; Peng, Bin; Wei, Yuquan

    2016-01-01

    Pseudomonas aeruginosa is a gram-negative bacterium and one of the leading causes of nosocomial infection worldwide, however, no effective vaccine is currently available in the market. Here, we demonstrate that inactivation of the bacteria by X-ray irradiation inhibits its replication capability but retained antigenic expression functionally thus allowing its use as a potential vaccine. Mice immunized by this vaccine were challenged by the parental strain, the O-antigen-homologous strain PAO-1 (O2/O5) and heterologous strain PAO-6 (O6) in an acute pneumonia model. We further measured the protective effect of the vaccine, as well as host innate and cellular immunity responses. We found immunized mice could protect against both strains. Notably, the antiserum only had significant protective role against similar bacteria, while adoptive transfer of lymphocytes significantly controlled the spread of the virulent heterologous serogroup PAO-6 infection, and the protective role could be reversed by CD4 rather than CD8 antibody. We further revealed that vaccinated mice could rapidly recruit neutrophils to the airways early after intranasal challenge by PAO-6, and the irradiated vaccine was proved to be protective by the generated CD4+ IL-17+ Th17 cells. In conclusion, the generation of inactivated but metabolically active microbes is a promising strategy for safely vaccinating against Pseudomonas aeruginosa. PMID:26879055

  1. 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...

  2. 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.

  3. Pseudomonas aeruginosa lectin LecB inhibits tissue repair processes by triggering β-catenin degradation

    PubMed Central

    Cott, Catherine; Thuenauer, Roland; Landi, Alessia; Kühn, Katja; Juillot, Samuel; Imberty, Anne; Madl, Josef; Eierhoff, Thorsten; Römer, Winfried

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that induces severe lung infections such as ventilator-associated pneumonia and acute lung injury. Under these conditions, the bacterium diminishes epithelial integrity and inhibits tissue repair mechanisms, leading to persistent infections. Understanding the involved bacterial virulence factors and their mode of action is essential for the development of new therapeutic approaches. In our study we discovered a so far unknown effect of the P. aeruginosa lectin LecB on host cell physiology. LecB alone was sufficient to attenuate migration and proliferation of human lung epithelial cells and to induce transcriptional activity of NF-κB. These effects are characteristic of impaired tissue repair. Moreover, we found a strong degradation of β-catenin, which was partially recovered by the proteasome inhibitor lactacystin. In addition, LecB induced loss of cell–cell contacts and reduced expression of the β-catenin targets c-myc and cyclin D1. Blocking of LecB binding to host cell plasma membrane receptors by soluble l-fucose prevented these changes in host cell behavior and signaling, and thereby provides a powerful strategy to suppress LecB function. Our findings suggest that P. aeruginosa employs LecB as a virulence factor to induce β-catenin degradation, which then represses processes that are directly linked to tissue recovery. PMID:26862060

  4. Pseudomonas aeruginosa AmpR: an acute–chronic switch regulator

    PubMed Central

    Balasubramanian, Deepak; Kumari, Hansi; Mathee, Kalai

    2015-01-01

    Pseudomonas aeruginosa is one of the most intractable human pathogens that pose serious clinical challenge due to extensive prevalence of multidrug-resistant clinical isolates. Armed with abundant virulence and antibiotic resistance mechanisms, it is a major etiologic agent in a number of acute and chronic infections. A complex and intricate network of regulators dictates the expression of pathogenicity factors in P. aeruginosa. Some proteins within the network play key roles and control multiple pathways. This review discusses the role of one such protein, AmpR, which was initially recognized for its role in antibiotic resistance by regulating AmpC β-lactamase. Recent genomic, proteomic and phenotypic analyses demonstrate that AmpR regulates expression of hundreds of genes that are involved in diverse pathways such as β-lactam and non-β-lactam resistance, quorum sensing and associated virulence phenotypes, protein phosphorylation, and physiological processes. Finally, ampR mutations in clinical isolates are reviewed to shed light on important residues required for its function in antibiotic resistance. The prevalence and evolutionary implications of AmpR in pathogenic and nonpathogenic proteobacteria are also discussed. A comprehensive understanding of proteins at nodal positions in the P. aeruginosa regulatory network is crucial in understanding, and ultimately targeting, the pathogenic stratagems of this organism. PMID:25066236

  5. Pseudomonas aeruginosa lectin LecB inhibits tissue repair processes by triggering β-catenin degradation.

    PubMed

    Cott, Catherine; Thuenauer, Roland; Landi, Alessia; Kühn, Katja; Juillot, Samuel; Imberty, Anne; Madl, Josef; Eierhoff, Thorsten; Römer, Winfried

    2016-06-01

    Pseudomonas aeruginosa is an opportunistic pathogen that induces severe lung infections such as ventilator-associated pneumonia and acute lung injury. Under these conditions, the bacterium diminishes epithelial integrity and inhibits tissue repair mechanisms, leading to persistent infections. Understanding the involved bacterial virulence factors and their mode of action is essential for the development of new therapeutic approaches. In our study we discovered a so far unknown effect of the P. aeruginosa lectin LecB on host cell physiology. LecB alone was sufficient to attenuate migration and proliferation of human lung epithelial cells and to induce transcriptional activity of NF-κB. These effects are characteristic of impaired tissue repair. Moreover, we found a strong degradation of β-catenin, which was partially recovered by the proteasome inhibitor lactacystin. In addition, LecB induced loss of cell-cell contacts and reduced expression of the β-catenin targets c-myc and cyclin D1. Blocking of LecB binding to host cell plasma membrane receptors by soluble l-fucose prevented these changes in host cell behavior and signaling, and thereby provides a powerful strategy to suppress LecB function. Our findings suggest that P. aeruginosa employs LecB as a virulence factor to induce β-catenin degradation, which then represses processes that are directly linked to tissue recovery. PMID:26862060

  6. Effects of Pseudomonas aeruginosa elastase on alveolar epithelial permeability in guinea pigs

    SciTech Connect

    Azghani, A.O.; Connelly, J.C.; Peterson, B.T.; Gray, L.D.; Collins, M.L.; Johnson, A.R. )

    1990-02-01

    Elastase-deficient mutants of Pseudomonas aeruginosa are less virulent than the wild type and are easily cleared from the lungs of guinea pigs. The effect of P. aeruginosa elastase on lung epithelium, however, is not yet understood. We addressed the hypothesis that breach of the epithelial barrier by elastase from P. aeruginosa allows invading organisms and toxic substances to penetrate the interstitium. We measured the clearance of aerosolized technetium-labeled albumin (molecular weight, 69,000) from the lungs of anesthetized guinea pigs with the aid of a gamma camera and a dedicated computer. Aerosols of the elastase (0.1 to 5 micrograms) increased the rate of clearance of labeled albumin from the lungs in proportion to the elastase dose. Electron microscopic studies using horseradish peroxidase as a tracer revealed that elastase interrupts intercellular tight junctions of the epithelial lining, thereby increasing the permeability to macromolecules. The amounts of elastase used in this report did not cause interstitial or alveolar edema, as determined by both postmortem extravascular lung water volume measurement and morphological examination. The data indicate that the elastase is a potentially important virulence factor in acute lung infection.

  7. 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.

  8. [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

  9. Paerucumarin, a new metabolite produced by the pvc gene cluster from Pseudomonas aeruginosa.

    PubMed

    Clarke-Pearson, Michael F; Brady, Sean F

    2008-10-01

    The pvc gene cluster from Pseudomonas aeruginosa has been linked to the biosynthesis of both the pyoverdine chromophore and pseudoverdine. Our reinvestigation of the role this gene cluster plays in P. aeruginosa secondary metabolite biosynthesis shows that its major product is actually paerucumarin, a novel isonitrile functionalized cumarin. PMID:18689486

  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. 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...

  12. Draft Genome Sequence of a Klebsiella pneumoniae Carbapenemase-Positive Sequence Type 111 Pseudomonas aeruginosa Strain

    PubMed Central

    Dotson, Gabrielle A.; Dekker, John P.; Palmore, Tara N.; Segre, Julia A.

    2016-01-01

    Here, we report the draft genome sequence of a sequence type 111 Pseudomonas aeruginosa strain isolated in 2014 from a patient at the NIH Clinical Center. This P. aeruginosa strain exhibits pan-drug resistance and harbors the blaKPC-2 gene, encoding the Klebsiella pneumoniae carbapenemase enzyme, on a plasmid. PMID:26868386

  13. 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

    2016-01-01

    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

  14. PSEUDOMONAS AERUGINOSA-FECAL COLIFORM RELATIONSHIPS IN ESTUARINE AND FRESH RECREATIONAL WATERS

    EPA Science Inventory

    This study has shown that Pseudomonas aeruginosa cannot be used as the basis of water standards for the prevention of enteric disease during the recreational use of surface waters. However, P. aeruginosa determinations, when used in conjunction with the assay of fecal coliforms o...

  15. MOLECULAR CHARACTERIZATION OF 'PSEUDOMONAS AERUGINOSA' BACTERIOPHAGES: IDENTIFICATION AND CHARACTERIZATION OF THE NOVEL VIRUS B86

    EPA Science Inventory

    The authors have characterized a new phage, B86, of Pseudomonas aeruginosa isolated from nature. It is a temperate, uv-inducible, generalized transducing phage. To determine the relatedness of his phage to other characterized P. aeruginosa phages, DNA homology studies were carrie...

  16. 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.

  17. Exploring the In Vitro Thrombolytic Activity of Nattokinase From a New Strain Pseudomonas aeruginosa CMSS

    PubMed Central

    Chandrasekaran, Subathra Devi; Vaithilingam, Mohanasrinivasan; Shanker, Ravi; Kumar, Sanjeev; Thiyur, Swathi; Babu, Vaishnavi; Selvakumar, Jemimah Naine; Prakash, Suyash

    2015-01-01

    Background: Thrombolytic therapy has become a conventional treatment for acute myocardial infarction (AMI), yet currently, clinically prescribed thrombolytic drugs have problems such as delayed action and other side effects. Fibrinolytic enzymes have attracted interest as thrombolytic agents because of their efficiency in the fibrinolytic process, including plasmin activation. Nattokinase (NK) is a potent fibrinolytic agent for thrombosis therapy. Objectives: The aim of this study was to enhance the production of NK from Pseudomonas aeruginosa CMSS by media optimization and strain improvement. Materials and Methods: In the present study, a potent NK-producing strain was isolated from cow milk and identified. To enhance the yield of NK, effect of various parameters such as pH, temperature, carbon source, nitrogen source and inoculum size were optimized. Strain improvement of P. aeruginosa CMSS was done by random UV-mutagenesis. Nattokinase was partially purified and the activity was determined by the casein digestion method, blood clot lysis and fibrin degradation assay. Results: Based on morphological, biochemical and molecular characterization, the strain was confirmed as P. aeruginosa (GenBank accession number: JX112657), designated as P. aeruginosa CMSS. The optimum condition at pH 7 and temperature at 25˚C showed activity of NK as 1514 U mL-1 and 1532 U mL-1, respectively. Sucrose as the carbon source and shrimp shell powder (SSP) as the nitrogen source expressed NK activity of 1721 U mL-1 and 2524 U mL-1, respectively. At 1% inoculum size, the maximum rate of enzyme production was achieved with 2581 U mL-1. The NK activity of the mutant strain UV60 was 4263 U mL-1, indicating a two-fold increase in activity compared to the wild strain (2581 UmL-1). Nattokinase produced from mutant strain P. aeruginosa CMSS UV60 showed 94% blood clot lysis at ten minutes. The degradation of fibrin clot by the produced NK was observed after two hours of incubation. Sodium

  18. Nitrite reductase is critical for Pseudomonas aeruginosa survival during co-infection with the oral commensal Streptococcus parasanguinis.

    PubMed

    Scoffield, Jessica A; Wu, Hui

    2016-02-01

    Pseudomonas aeruginosa is the major aetiological agent of chronic pulmonary infections in cystic fibrosis (CF) patients. However, recent evidence suggests that the polymicrobial community of the CF lung may also harbour oral streptococci, and colonization by these micro-organisms may have a negative impact on P. aeruginosa within the CF lung. Our previous studies demonstrated that nitrite abundance plays an important role in P. aeruginosa survival during co-infection with oral streptococci. Nitrite reductase is a key enzyme involved in nitrite metabolism. Therefore, the objective of this study was to examine the role nitrite reductase (gene nirS) plays in P. aeruginosa survival during co-infection with an oral streptococcus, Streptococcus parasanguinis. Inactivation of nirS in both the chronic CF isolate FRD1 and acute wound isolate PAO1 reduced the survival rate of P. aeruginosa when co-cultured with S. parasanguinis. Growth of both mutants was restored when co-cultured with S. parasanguinis that was defective for H2O2 production. Furthermore, the nitrite reductase mutant was unable to kill Drosophila melanogaster during co-infection with S. parasanguinis. Taken together, these results suggest that nitrite reductase plays an important role for survival of P. aeruginosa during co-infection with S. parasanguinis. PMID:26673783

  19. 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

  20. Pseudomonas aeruginosa outbreak in a pediatric oncology care unit caused by an errant water jet into contaminated siphons.

    PubMed

    Schneider, Henriette; Geginat, Gernot; Hogardt, Michael; Kramer, Alexandra; Dürken, Matthias; Schroten, Horst; Tenenbaum, Tobias

    2012-06-01

    We analyzed an outbreak of invasive infections with an exotoxin U positive Pseudomonas aeruginosa strain within a pediatric oncology care unit. Environmental sampling and molecular characterization of the Pseudomonas aeruginosa strains led to identification of the outbreak source. An errant water jet into the sink within patient rooms was observed. Optimized outbreak management resulted in an abundance of further Pseudomonas aeruginosa infections within the pediatric oncology care unit. PMID:22333699

  1. Dual promoters of the major catalase (KatA) govern distinct survival strategies of Pseudomonas aeruginosa

    PubMed Central

    Chung, In-Young; Kim, Bi-o; Jang, Hye-Jeong; Cho, You-Hee

    2016-01-01

    KatA is the major catalase required for hydrogen peroxide (H2O2) resistance and acute virulence in Pseudomonas aeruginosa PA14, whose transcription is driven from the promoter (katAp1) located at 155 nucleotide (nt) upstream of the start codon. Here, we identified another promoter (katAp2), the +1 of which was mapped at the 51 nt upstream of the start codon, which was responsible for the basal transcription during the planktonic culture and down-regulated upon H2O2 treatment under the control by the master regulator of anaerobiosis, Anr. To dissect the roles of the dual promoters in conditions involving KatA, we created the promoter mutants for each -10 box (p1m, p2m, and p1p2m) and found that katAp1 is required for the function of KatA in the logarithmic growth phase during the planktonic culture as well as in acute virulence, whereas katAp2 is required for the function of KatA in the stationary phase as well as in the prolonged biofilm culture. This dismantling of the dual promoters of katA sheds light on the roles of KatA in stress resistance in both proliferative and growth-restrictive conditions and thus provides an insight into the regulatory impacts of the major catalase on the survival strategies of P. aeruginosa. PMID:27491679

  2. 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

  3. 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

  4. Structural Characterization of Novel Pseudomonas aeruginosa Type IV Pilins

    SciTech Connect

    Nguyen, Y.; Jackson, S; Aidoo, F; Junop, M; Burrows, L

    2010-01-01

    Pseudomonas aeruginosa type IV pili, composed of PilA subunits, are used for attachment and twitching motility on surfaces. P. aeruginosa strains express one of five phylogenetically distinct PilA proteins, four of which are associated with accessory proteins that are involved either in pilin posttranslational modification or in modulation of pilus retraction dynamics. Full understanding of pilin diversity is crucial for the development of a broadly protective pilus-based vaccine. Here, we report the 1.6-{angstrom} X-ray crystal structure of an N-terminally truncated form of the novel PilA from strain Pa110594 (group V), which represents the first non-group II pilin structure solved. Although it maintains the typical T4a pilin fold, with a long N-terminal {alpha}-helix and four-stranded antiparallel {beta}-sheet connected to the C-terminus by a disulfide-bonded loop, the presence of an extra helix in the {alpha}{beta}-loop and a disulfide-bonded loop with helical character gives the structure T4b pilin characteristics. Despite the presence of T4b features, the structure of PilA from strain Pa110594 is most similar to the Neisseria gonorrhoeae pilin and is also predicted to assemble into a fiber similar to the GC pilus, based on our comparative pilus modeling. Interactions between surface-exposed areas of the pilin are suggested to contribute to pilus fiber stability. The non-synonymous sequence changes between group III and V pilins are clustered in the same surface-exposed areas, possibly having an effect on accessory protein interactions. However, based on our high-confidence model of group III PilA{sub PA14}, compensatory changes allow for maintenance of a similar shape.

  5. Biological markers of Pseudomonas aeruginosa epidemic high-risk clones.

    PubMed

    Mulet, Xavier; Cabot, Gabriel; Ocampo-Sosa, Alain A; Domínguez, M Angeles; Zamorano, Laura; Juan, Carlos; Tubau, Fe; Rodríguez, Cristina; Moyà, Bartolomé; Peña, Carmen; Martínez-Martínez, Luis; Oliver, Antonio

    2013-11-01

    A limited number of Pseudomonas aeruginosa genotypes (mainly ST-111, ST-175, and ST-235), known as high-risk clones, are responsible for epidemics of nosocomial infections by multidrug-resistant (MDR) or extensively drug-resistant (XDR) strains worldwide. We explored the potential biological parameters that may explain the success of these clones. A total of 20 isolates from each of 4 resistance groups (XDR, MDR, ModR [resistant to 1 or 2 classes], and MultiS [susceptible to all antipseudomonals]), recovered from a multicenter study of P. aeruginosa bloodstream infections performed in 10 Spanish hospitals, were analyzed. A further set of 20 XDR isolates belonging to epidemic high-risk clones (ST-175 [n = 6], ST-111 [n = 7], and ST-235 [n = 7]) recovered from different geographical locations was also studied. When unknown, genotypes were documented through multilocus sequence typing. The biological parameters evaluated included twitching, swimming, and swarming motility, biofilm formation, production of pyoverdine and pyocyanin, spontaneous mutant frequencies, and the in vitro competition index (CI) obtained with a flow cytometry assay. All 20 (100%) XDR, 8 (40%) MDR, and 1 (5%) ModR bloodstream isolate from the multicenter study belonged to high-risk clones. No significant differences were observed between clonally diverse ModR and MultiS isolates for any of the parameters. In contrast, MDR/XDR high-risk clones showed significantly increased biofilm formation and mutant frequencies but significantly reduced motility (twitching, swimming, and swarming), production of pyoverdine and pyocyanin, and fitness. The defined biological markers of high-risk clones, which resemble those resulting from adaptation to chronic infections, could be useful for the design of specific treatment and infection control strategies. PMID:23979744

  6. Dispersion of TiO₂ nanoparticle agglomerates by Pseudomonas aeruginosa.

    PubMed

    Horst, Allison M; Neal, Andrea C; Mielke, Randall E; Sislian, Patrick R; Suh, Won Hyuk; Mädler, Lutz; Stucky, Galen D; Holden, Patricia A

    2010-11-01

    Engineered nanoparticles are increasingly incorporated into consumer products and are emerging as potential environmental contaminants. Upon environmental release, nanoparticles could inhibit bacterial processes, as evidenced by laboratory studies. Less is known regarding bacterial alteration of nanoparticles, including whether bacteria affect physical agglomeration states controlling nanoparticle settling and bioavailability. Here, the effects of an environmental strain of Pseudomonas aeruginosa on TiO₂ nanoparticle agglomerates formed in aqueous media are described. Environmental scanning electron microscopy and cryogenic scanning electron microscopy visually demonstrated bacterial dispersion of large agglomerates formed in cell culture medium and in marsh water. For experiments in cell culture medium, quantitative image analysis verified that the degrees of conversion of large agglomerates into small nanoparticle-cell combinations were similar for 12-h-growth and short-term cell contact experiments. Dispersion in cell growth medium was further characterized by size fractionation: for agglomerated TiO₂ suspensions in the absence of cells, 81% by mass was retained on a 5-μm-pore-size filter, compared to only 24% retained for biotic treatments. Filtrate cell and agglomerate sizes were characterized by dynamic light scattering, revealing that the average bacterial cell size increased from 1.4 μm to 1.9 μm because of nano-TiO₂ biosorption. High-magnification scanning electron micrographs showed that P. aeruginosa dispersed TiO₂ agglomerates by preferential biosorption of nanoparticles onto cell surfaces. These results suggest a novel role for bacteria in the environmental transport of engineered nanoparticles, i.e., growth-independent, bacterially mediated size and mass alterations of TiO₂ nanoparticle agglomerates. PMID:20851981

  7. 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

  8. 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.

  9. 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. PMID:24465697

  10. Biological Markers of Pseudomonas aeruginosa Epidemic High-Risk Clones

    PubMed Central

    Mulet, Xavier; Cabot, Gabriel; Ocampo-Sosa, Alain A.; Domínguez, M. Angeles; Zamorano, Laura; Juan, Carlos; Tubau, Fe; Rodríguez, Cristina; Moyà, Bartolomé; Peña, Carmen; Martínez-Martínez, Luis

    2013-01-01

    A limited number of Pseudomonas aeruginosa genotypes (mainly ST-111, ST-175, and ST-235), known as high-risk clones, are responsible for epidemics of nosocomial infections by multidrug-resistant (MDR) or extensively drug-resistant (XDR) strains worldwide. We explored the potential biological parameters that may explain the success of these clones. A total of 20 isolates from each of 4 resistance groups (XDR, MDR, ModR [resistant to 1 or 2 classes], and MultiS [susceptible to all antipseudomonals]), recovered from a multicenter study of P. aeruginosa bloodstream infections performed in 10 Spanish hospitals, were analyzed. A further set of 20 XDR isolates belonging to epidemic high-risk clones (ST-175 [n = 6], ST-111 [n = 7], and ST-235 [n = 7]) recovered from different geographical locations was also studied. When unknown, genotypes were documented through multilocus sequence typing. The biological parameters evaluated included twitching, swimming, and swarming motility, biofilm formation, production of pyoverdine and pyocyanin, spontaneous mutant frequencies, and the in vitro competition index (CI) obtained with a flow cytometry assay. All 20 (100%) XDR, 8 (40%) MDR, and 1 (5%) ModR bloodstream isolate from the multicenter study belonged to high-risk clones. No significant differences were observed between clonally diverse ModR and MultiS isolates for any of the parameters. In contrast, MDR/XDR high-risk clones showed significantly increased biofilm formation and mutant frequencies but significantly reduced motility (twitching, swimming, and swarming), production of pyoverdine and pyocyanin, and fitness. The defined biological markers of high-risk clones, which resemble those resulting from adaptation to chronic infections, could be useful for the design of specific treatment and infection control strategies. PMID:23979744

  11. Fitness of Isogenic Colony Morphology Variants of Pseudomonas aeruginosa in Murine Airway Infection

    PubMed Central

    Rakhimova, Elza; Munder, Antje; Wiehlmann, Lutz; Bredenbruch, Florian; Tümmler, Burkhard

    2008-01-01

    Chronic lung infections with Pseudomonas aeruginosa are associated with the diversification of the persisting clone into niche specialists and morphotypes, a phenomenon called ‘dissociative behaviour’. To explore the potential of P. aeruginosa to change its morphotype by single step loss-of–function mutagenesis, a signature-tagged mini-Tn5 plasposon library of the cystic fibrosis airway isolate TBCF10839 was screened for colony morphology variants under nine different conditions in vitro. Transposon insertion into 1% of the genome changed colony morphology into eight discernable morphotypes. Half of the 55 targets encode features of primary or secondary metabolism whereby quinolone production was frequently affected. In the other half the transposon had inserted into genes of the functional categories transport, regulation or motility/chemotaxis. To mimic dissociative behaviour of isogenic strains in lungs, pools of 25 colony morphology variants were tested for competitive fitness in an acute murine airway infection model. Six of the 55 mutants either grew better or worse in vivo than in vitro, respectively. Metabolic proficiency of the colony morphology variant was a key determinant for survival in murine airways. The most common morphotype of self-destructive autolysis did unexpectedly not impair fitness. Transposon insertions into homologous genes of strain PAO1 did not reproduce the TBCF10839 mutant morphotypes for 16 of 19 examined loci pointing to an important role of the genetic background on colony morphology. Depending on the chosen P. aeruginosa strain, functional genome scans will explore other areas of the evolutionary landscape. Based on our discordant findings of mutant phenotypes in P. aeruginosa strains PAO1, PA14 and TBCF10839, we conclude that the current focus on few reference strains may miss modes of niche adaptation and dissociative behaviour that are relevant for the microevolution of complex traits in the wild. PMID:18301762

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

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

    2016-01-01

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

  14. Differential ASC requirements reveal a key role for neutrophils and a noncanonical IL-1β response to Pseudomonas aeruginosa.

    PubMed

    Patankar, Yash R; Mabaera, Rodwell; Berwin, Brent

    2015-10-15

    The NLRC4 inflammasome is responsible for IL-1β processing by macrophages in response to Pseudomonas aeruginosa infection. We therefore hypothesized that mice that lack ASC, an NLRC4 inflammasome adaptor protein necessary for in vitro IL-1β production by macrophages, would be preferentially protected from a hyperinflammatory lethal challenge that is dependent on bacterial type three secretion system (T3SS) activity. We report herein that lack of ASC does not confer preferential protection in response to P. aeruginosa acute infection and that ASC(-/-) mice are capable of producing robust amounts of IL-1β comparable with C57BL/6 mice. We now identify that neutrophils represent the ASC-independent source of IL-1β production during the acute phases of infection both in models of acute pneumonia and peritonitis. Consequently, depletion of neutrophils in ASC(-/-) mice leads to a marked deficit in IL-1β production in vivo. The pulmonary neutrophil IL-1β response is predominantly dependent on caspase-1, which contrasts with data derived from ocular infection. These studies therefore identify a noncanonical mechanism of IL-1β production by neutrophils independent of ASC and demonstrate the first physiological contribution of neutrophils as an important source of IL-1β in response to acute P. aeruginosa infection during acute pneumonia and peritonitis. PMID:26472815

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

    PubMed

    Marvig, Rasmus Lykke; Sommer, Lea M; Jelsbak, Lars; Molin, Søren; Johansen, Helle Krogh

    2015-01-01

    The opportunistic pathogen Pseudomonas aeruginosa causes chronic airway infections in patients with cystic fibrosis (CF), and it is directly associated with the morbidity and mortality connected with this disease. The ability of P. aeruginosa to establish chronic infections in CF patients is suggested to be due to the large genetic repertoire of P. aeruginosa and its ability to genetically adapt to the host environment. Here, we review the recent work that has applied whole-genome sequencing to understand P. aeruginosa population genomics, within-host microevolution and diversity, mutational mechanisms, genetic adaptation and transmission events. Finally, we summarize the advances in relation to medical applications and laboratory evolution experiments. PMID:25865196

  16. Targeting the Type Three Secretion System in Pseudomonas aeruginosa.

    PubMed

    Anantharajah, Ahalieyah; Mingeot-Leclercq, Marie-Paule; Van Bambeke, Françoise

    2016-09-01

    The injectisome type three secretion system (T3SS) is a major virulence factor in Pseudomonas aeruginosa. This bacterium is responsible for severe infections in immunosuppressed or cystic fibrosis patients and has become resistant to many antibiotics. Inhibitors of T3SS may therefore constitute an innovative therapeutic target. After a brief description of the T3SS and its regulation, this review presents strategies to inhibit T3SS-mediated toxicity and describes the main families of existing inhibitors. Over the past few years, 12 classes of small-molecule inhibitors and two types of antibody have been discovered and evaluated in vitro for their capacity to inhibit T3SS expression or function, and to protect host cells from T3SS-mediated cytotoxicity. While only one small molecule has been tested in vivo, a bifunctional antibody targeting both the translocation apparatus of the T3SS and a surface polysaccharide is currently in Phase II clinical trials. PMID:27344210

  17. Variability in Pseudomonas aeruginosa Lipopolysaccharide Expression during Crude Oil Degradation

    PubMed Central

    Norman, R. Sean; Frontera-Suau, Roberto; Morris, Pamela J.

    2002-01-01

    Bacterial utilization of crude oil components, such as the n-alkanes, requires complex cell surface adaptation to allow adherence to oil. To better understand microbial cell surface adaptation to growth on crude oil, the cell surface characteristics of two Pseudomonas aeruginosa strains, U1 and U3, both isolated from the same crude oil-degrading microbial community enriched on Bonny Light crude oil (BLC), were compared. Analysis of growth rates demonstrated an increased lag time for U1 cells compared to U3 cells. Amendment with EDTA inhibited U1 and U3 growth and degradation of the n-alkane component of BLC, suggesting a link between cell surface structure and crude oil degradation. U1 cells demonstrated a smooth-to-rough colony morphology transition when grown on BLC, while U3 cells exhibited rough colony morphology at the outset. Combining high-resolution atomic force microscopy of the cell surface and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of extracted lipopolysaccharides (LPS), we demonstrate that isolates grown on BLC have reduced O-antigen expression compared with that of glucose-grown cells. The loss of O-antigen resulted in shorter LPS molecules, increased cell surface hydrophobicity, and increased n-alkane degradation. PMID:12324360

  18. PA0148 from Pseudomonas aeruginosa Catalyzes the Deamination of Adenine

    SciTech Connect

    Goble, A.M.; Swaminathan, S.; Zhang, Z.; Sauder, J. M.; Burley, S. K.; Raushel, F. M.

    2011-08-02

    Four proteins from NCBI cog1816, previously annotated as adenosine deaminases, have been subjected to structural and functional characterization. Pa0148 (Pseudomonas aeruginosa PAO1), AAur1117 (Arthrobacter aurescens TC1), Sgx9403e, and Sgx9403g have been purified and their substrate profiles determined. Adenosine is not a substrate for any of these enzymes. All of these proteins will deaminate adenine to produce hypoxanthine with k{sub cat}/K{sub m} values that exceed 10{sup 5} M{sup -1} s{sup -1}. These enzymes will also accept 6-chloropurine, 6-methoxypurine, N-6-methyladenine, and 2,6-diaminopurine as alternate substrates. X-ray structures of Pa0148 and AAur1117 have been determined and reveal nearly identical distorted ({beta}/{alpha}){sub 8} barrels with a single zinc ion that is characteristic of members of the amidohydrolase superfamily. Structures of Pa0148 with adenine, 6-chloropurine, and hypoxanthine were also determined, thereby permitting identification of the residues responsible for coordinating the substrate and product.

  19. Pa0148 from Pseudomonas aeruginosa Catalyzes the Deamination of Adenine

    SciTech Connect

    A Goble; Z Zhang; J Sauder; S Burley; S Swaminathan; F Raushel

    2011-12-31

    Four proteins from NCBI cog1816, previously annotated as adenosine deaminases, have been subjected to structural and functional characterization. Pa0148 (Pseudomonas aeruginosa PAO1), AAur1117 (Arthrobacter aurescens TC1), Sgx9403e, and Sgx9403g have been purified and their substrate profiles determined. Adenosine is not a substrate for any of these enzymes. All of these proteins will deaminate adenine to produce hypoxanthine with k{sub cat}/K{sub m} values that exceed 10{sup 5} M{sup -1} s{sup -1}. These enzymes will also accept 6-chloropurine, 6-methoxypurine, N-6-methyladenine, and 2,6-diaminopurine as alternate substrates. X-ray structures of Pa0148 and AAur1117 have been determined and reveal nearly identical distorted ({beta}/{alpha}){sub 8} barrels with a single zinc ion that is characteristic of members of the amidohydrolase superfamily. Structures of Pa0148 with adenine, 6-chloropurine, and hypoxanthine were also determined, thereby permitting identification of the residues responsible for coordinating the substrate and product.

  20. Crystal structure of Pseudomonas aeruginosa bacteriophytochrome: Photoconversion and signal transduction

    SciTech Connect

    Yang, Xiaojing; Kuk, Jane; Moffat, Keith

    2008-11-12

    Phytochromes are red-light photoreceptors that regulate light responses in plants, fungi, and bacteria via reversible photoconversion between red (Pr) and far-red (Pfr) light-absorbing states. Here we report the crystal structure at 2.9 {angstrom} resolution of a bacteriophytochrome from Pseudomonas aeruginosa with an intact, fully photoactive photosensory core domain in its dark-adapted Pfr state. This structure reveals how unusual interdomain interactions, including a knot and an 'arm' structure near the chromophore site, bring together the PAS (Per-ARNT-Sim), GAF (cGMP phosphodiesterase/adenyl cyclase/FhlA), and PHY (phytochrome) domains to achieve Pr/Pfr photoconversion. The PAS, GAF, and PHY domains have topologic elements in common and may have a single evolutionary origin. We identify key interactions that stabilize the chromophore in the Pfr state and provide structural and mutational evidence to support the essential role of the PHY domain in efficient Pr/Pfr photoconversion. We also identify a pair of conserved residues that may undergo concerted conformational changes during photoconversion. Modeling of the full-length bacteriophytochrome structure, including its output histidine kinase domain, suggests how local structural changes originating in the photosensory domain modulate interactions between long, cross-domain signaling helices at the dimer interface and are transmitted to the spatially distant effector domain, thereby regulating its histidine kinase activity.

  1. Crystal structure of Pseudomonas aeruginosa bacteriophytochrome: photoconversion and signal transduction.

    PubMed

    Yang, Xiaojing; Kuk, Jane; Moffat, Keith

    2008-09-23

    Phytochromes are red-light photoreceptors that regulate light responses in plants, fungi, and bacteria via reversible photoconversion between red (Pr) and far-red (Pfr) light-absorbing states. Here we report the crystal structure at 2.9 A resolution of a bacteriophytochrome from Pseudomonas aeruginosa with an intact, fully photoactive photosensory core domain in its dark-adapted Pfr state. This structure reveals how unusual interdomain interactions, including a knot and an "arm" structure near the chromophore site, bring together the PAS (Per-ARNT-Sim), GAF (cGMP phosphodiesterase/adenyl cyclase/FhlA), and PHY (phytochrome) domains to achieve Pr/Pfr photoconversion. The PAS, GAF, and PHY domains have topologic elements in common and may have a single evolutionary origin. We identify key interactions that stabilize the chromophore in the Pfr state and provide structural and mutational evidence to support the essential role of the PHY domain in efficient Pr/Pfr photoconversion. We also identify a pair of conserved residues that may undergo concerted conformational changes during photoconversion. Modeling of the full-length bacteriophytochrome structure, including its output histidine kinase domain, suggests how local structural changes originating in the photosensory domain modulate interactions between long, cross-domain signaling helices at the dimer interface and are transmitted to the spatially distant effector domain, thereby regulating its histidine kinase activity. PMID:18799746

  2. Siderophore-mediated cooperation and virulence in Pseudomonas aeruginosa.

    PubMed

    Buckling, Angus; Harrison, Freya; Vos, Michiel; Brockhurst, Michael A; Gardner, Andy; West, Stuart A; Griffin, Ashleigh

    2007-11-01

    Why should organisms cooperate with each other? Helping close relatives that are likely to share the same genes (kin selection) is one important explanation that is likely to apply across taxa. The production of metabolically costly extracellular iron-scavenging molecules (siderophores) by microorganisms is a cooperative behaviour because it benefits nearby conspecifics. We review experiments focusing on the production of the primary siderophore (pyoverdin) of the opportunistic bacterial pathogen, Pseudomonas aeruginosa, which test kin selection theories that seek to explain the evolution of cooperation. First, cooperation is indeed favoured when individuals interact with their close relatives and when there is competition between groups of cooperators and noncooperators, such that the benefit of cooperation can be realized. Second, the relative success of cheats and cooperators is a function of their frequencies within populations. Third, elevated mutation rates can confer a selective disadvantage under conditions when cooperation is beneficial, because high mutation rates reduce how closely bacteria are related to each other. Fourth, cooperative pyoverdin production is also shown to be favoured by kin selection in vivo (caterpillars), and results in more virulent infections. Finally, we briefly outline ongoing and future work using this experimental system. PMID:17919300

  3. 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.

  4. 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

  5. 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

  6. 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

  7. Functional analysis of the Pseudomonas aeruginosa autoinducer PAI.

    PubMed

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

    1996-10-01

    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

  8. Pseudomonas aeruginosa Promotes Escherichia coli Biofilm Formation in Nutrient-Limited Medium

    PubMed Central

    Culotti, Alessandro; Packman, Aaron I.

    2014-01-01

    Biofilms have been implicated as an important reservoir for pathogens and commensal enteric bacteria such as Escherichia coli in natural and engineered water systems. However, the processes that regulate the survival of E. coli in aquatic biofilms have not been thoroughly studied. We examined the effects of hydrodynamic shear and nutrient concentrations on E. coli colonization of pre-established Pseudomonas aeruginosa biofilms, co-inoculation of E. coli and P. aeruginosa biofilms, and P. aeruginosa colonization of pre-established E. coli biofilms. In nutritionally-limited R2A medium, E. coli dominated biofilms when co-inoculated with P. aeruginosa, and successfully colonized and overgrew pre-established P. aeruginosa biofilms. In more enriched media, P. aeruginosa formed larger clusters, but E. coli still extensively overgrew and colonized the interior of P. aeruginosa clusters. In mono-culture, E. coli formed sparse and discontinuous biofilms. After P. aeruginosa was introduced to these biofilms, E. coli growth increased substantially, resulting in patterns of biofilm colonization similar to those observed under other sequences of organism introduction, i.e., E. coli overgrew P. aeruginosa and colonized the interior of P. aeruginosa clusters. These results demonstrate that E. coli not only persists in aquatic biofilms under depleted nutritional conditions, but interactions with P. aeruginosa can greatly increase E. coli growth in biofilms under these experimental conditions. PMID:25198725

  9. 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. PMID:26610432

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

    PubMed

    Culotti, Alessandro; Packman, Aaron I

    2014-01-01

    Biofilms have been implicated as an important reservoir for pathogens and commensal enteric bacteria such as Escherichia coli in natural and engineered water systems. However, the processes that regulate the survival of E. coli in aquatic biofilms have not been thoroughly studied. We examined the effects of hydrodynamic shear and nutrient concentrations on E. coli colonization of pre-established Pseudomonas aeruginosa biofilms, co-inoculation of E. coli and P. aeruginosa biofilms, and P. aeruginosa colonization of pre-established E. coli biofilms. In nutritionally-limited R2A medium, E. coli dominated biofilms when co-inoculated with P. aeruginosa, and successfully colonized and overgrew pre-established P. aeruginosa biofilms. In more enriched media, P. aeruginosa formed larger clusters, but E. coli still extensively overgrew and colonized the interior of P. aeruginosa clusters. In mono-culture, E. coli formed sparse and discontinuous biofilms. After P. aeruginosa was introduced to these biofilms, E. coli growth increased substantially, resulting in patterns of biofilm colonization similar to those observed under other sequences of organism introduction, i.e., E. coli overgrew P. aeruginosa and colonized the interior of P. aeruginosa clusters. These results demonstrate that E. coli not only persists in aquatic biofilms under depleted nutritional conditions, but interactions with P. aeruginosa can greatly increase E. coli growth in biofilms under these experimental conditions. PMID:25198725

  11. Oral bacteria modulate invasion and induction of apoptosis in HEp-2 cells by Pseudomonas aeruginosa.

    PubMed

    Pan, Yaping; Teng, Di; Burke, Andrew C; Haase, Elaine M; Scannapieco, Frank A

    2009-02-01

    Pseudomonas aeruginosa is an important opportunistic bacterial pathogen, causing infections of the respiratory and other organ systems in susceptible hosts. P. aeruginosa infection is initiated by adhesion to and invasion of mucosal epithelial cells. The failure of host defenses to eliminate P. aeruginosa from mucosal surfaces results in P. aeruginosa proliferation, sometimes followed by overt infection and tissue destruction. There is growing evidence that associates poor oral health and respiratory infection. An in vitro model system for bacterial invasion of respiratory epithelial cells was used to investigate the influence of oral bacteria on P. aeruginosa epithelial cell invasion. Oral pathogens including Porphyromonas gingivalis, Fusobacterium nucleatum and Aggregatibacter (Actinobacillus) actinomycetemcomitans increased invasion of P. aeruginosa into HEp-2 cells from one- to threefold. In contrast, non-pathogenic oral bacteria such as Actinomyces naeslundii and Streptococcus gordonii showed no significant influence on P. aeruginosa invasion. P. aeruginosa together with oral bacteria stimulated greater cytokine production from HEp-2 cells than did P. aeruginosa alone. P. aeruginosa in combination with periodontal pathogens also increased apoptosis of HEp-2 cells and induced elevated caspase-3 activity. These results suggest that oral bacteria, especially periodontal pathogens, may foster P. aeruginosa invasion into respiratory epithelial cells to enhance host cell cytokine release and apoptosis. PMID:19041936

  12. The T6SSs of Pseudomonas aeruginosa Strain PAO1 and Their Effectors: Beyond Bacterial-Cell Targeting

    PubMed Central

    Sana, Thibault G.; Berni, Benjamin; Bleves, Sophie

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen responsible for many diseases such as chronic lung colonization in cystic fibrosis patients and acute infections in hospitals. The capacity of P. aeruginosa to be pathogenic toward several hosts is notably due to different secretion systems. Amongst them, P. aeruginosa encodes three Type Six Secretion Systems (T6SS), named H1- to H3-T6SS, that act against either prokaryotes and/or eukaryotic cells. They are independent from each other and inject diverse toxins that interact with different components in the host cell. Here we summarize the roles of these T6SSs in the PAO1 strain, as well as the toxins injected and their targets. While H1-T6SS is only involved in antiprokaryotic activity through at least seven different toxins, H2-T6SS and H3-T6SS are also able to target prokaryotic as well as eukaryotic cells. Moreover, recent studies proposed that H2- and H3-T6SS have a role in epithelial cells invasion by injecting at least three different toxins. The diversity of T6SS effectors is astounding and other effectors still remain to be discovered. In this review, we present a table with other putative P. aeruginosa strain PAO1 T6SS-dependent effectors. Altogether, the T6SSs of P. aeruginosa are important systems that help fight other bacteria for their ecological niche, and are important in the pathogenicity process. PMID:27376031

  13. Heavy metal resistance and virulence profile in Pseudomonas aeruginosa isolated from Brazilian soils.

    PubMed

    Pitondo-Silva, André; Gonçalves, Guilherme Bartolomeu; Stehling, Eliana Guedes

    2016-08-01

    Pseudomonas aeruginosa is an opportunistic pathogen, which can have several virulence factors that confer on it the ability to cause severe, acute and chronic infections. Thus, the simultaneous occurrence of resistance to antibiotics and heavy metals associated with the presence of virulence genes is a potential threat to human health and environmental balance. This study aimed to investigate the resistance profile to heavy metals and the correlation of this phenotype of resistance to antimicrobials and to investigate the pathogenic potential of 46 P. aeruginosa isolates obtained from the soil of five Brazilian regions. The bacteria were evaluating for antimicrobial and heavy metal resistance, as well as the presence of plasmids and virulence genes. The isolates showed resistance to four different antibiotics and the majority (n = 44) had resistance to aztreonam or ticarcillin, furthermore, 32 isolates showed concomitant resistance to both of these antibiotics. A high prevalence of virulence genes was found, which highlights the pathogenic potential of the studied environmental isolates. Moreover, a high frequency of heavy metal resistance genes was also detected, however, the phenotypic results indicated that other genes and/or mechanisms should be related to heavy metal resistance. PMID:27197940

  14. Oligoribonuclease is required for the type III secretion system and pathogenesis of Pseudomonas aeruginosa.

    PubMed

    Chen, Gukui; Zhao, Qiang; Zhu, Feng; Chen, Ronghao; Jin, Yongxin; Liu, Chang; Pan, Xiaolei; Jin, Shouguang; Wu, Weihui; Cheng, Zhihui

    2016-01-01

    Oligoribonuclease (Orn) is a 3' to 5' exonuclease that degrades nanoRNAs, which can serve as primers for transcription initiation at a significant fraction of promoters. One of Orn's substrates, pGpG inhibits the enzymatic activity of EAL-domain containing phosphodiesterases (PDEs), thereby increasing intracellular cyclic-di-GMP (c-di-GMP) level. Here, we found that an orn mutant of Pseudomonas aeruginosa displayed reduced cytotoxicity, which was mainly due to deficient type III secretion system (T3SS). Given the importance of T3SS in pathogenicity, we examined the bacterial virulence in a mouse acute pneumonia model and found that the Δorn mutant was highly attenuated compared to the wild type PA14 strain. Overexpression of an EAL domain-containing PDE reduced the c-di-GMP level as well as biofilm formation in the Δorn mutant. However, no effect was observed on the expression of T3SS genes, suggesting that increased c-di-GMP level is not the solely cause of defective T3SS in the Δorn mutant. Overall, our results demonstrated an essential role of Orn in the expression of T3SS as well as pathogenesis of P. aeruginosa. PMID:27296966

  15. Efflux as a glutaraldehyde resistance mechanism in Pseudomonas fluorescens and Pseudomonas aeruginosa biofilms.

    PubMed

    Vikram, Amit; Bomberger, Jennifer M; Bibby, Kyle J

    2015-01-01

    A major challenge in microbial biofilm control is biocide resistance. Phenotypic adaptations and physical protective effects have been historically thought to be the primary mechanisms for glutaraldehyde resistance in bacterial biofilms. Recent studies indicate the presence of genetic mechanisms for glutaraldehyde resistance, but very little is known about the contributory genetic factors. Here, we demonstrate that efflux pumps contribute to glutaraldehyde resistance in Pseudomonas fluorescens and Pseudomonas aeruginosa biofilms. The RNA-seq data show that efflux pumps and phosphonate degradation, lipid biosynthesis, and polyamine biosynthesis metabolic pathways were induced upon glutaraldehyde exposure. Furthermore, chemical inhibition of efflux pumps potentiates glutaraldehyde activity, suggesting that efflux activity contributes to glutaraldehyde resistance. Additionally, induction of known modulators of biofilm formation, including phosphonate degradation, lipid biosynthesis, and polyamine biosynthesis, may contribute to biofilm resistance and resilience. Fundamental understanding of the genetic mechanism of biocide resistance is critical for the optimization of biocide use and development of novel disinfection strategies. Our results reveal genetic components involved in glutaraldehyde resistance and a potential strategy for improved control of biofilms. PMID:25824217

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

    PubMed Central

    Vikram, Amit; Bomberger, Jennifer M.

    2015-01-01

    A major challenge in microbial biofilm control is biocide resistance. Phenotypic adaptations and physical protective effects have been historically thought to be the primary mechanisms for glutaraldehyde resistance in bacterial biofilms. Recent studies indicate the presence of genetic mechanisms for glutaraldehyde resistance, but very little is known about the contributory genetic factors. Here, we demonstrate that efflux pumps contribute to glutaraldehyde resistance in Pseudomonas fluorescens and Pseudomonas aeruginosa biofilms. The RNA-seq data show that efflux pumps and phosphonate degradation, lipid biosynthesis, and polyamine biosynthesis metabolic pathways were induced upon glutaraldehyde exposure. Furthermore, chemical inhibition of efflux pumps potentiates glutaraldehyde activity, suggesting that efflux activity contributes to glutaraldehyde resistance. Additionally, induction of known modulators of biofilm formation, including phosphonate degradation, lipid biosynthesis, and polyamine biosynthesis, may contribute to biofilm resistance and resilience. Fundamental understanding of the genetic mechanism of biocide resistance is critical for the optimization of biocide use and development of novel disinfection strategies. Our results reveal genetic components involved in glutaraldehyde resistance and a potential strategy for improved control of biofilms. PMID:25824217

  17. 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. PMID:25093328

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

    PubMed

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

    1996-07-01

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

  19. Epidemiological analysis of serum anti-Pseudomonas aeruginosa PcrV titers in adults.

    PubMed

    Yasumoto, Hiroaki; Katoh, Hideya; Kinoshita, Mao; Shimizu, Masaru; Hamaoka, Saeko; Akiyama, Koichi; Naito, Yoshifumi; Sawa, Teiji

    2016-02-01

    Of the various virulence mechanisms of the opportunistic pathogen Pseudomonas aeruginosa, the type III secretion system (TTSS) has been characterized as a major factor associated with acute lung injury, bacteremia and mortality. In addition, PcrV, a component protein of the TTSS, has been characterized as a protective antigen against infection with P. aeruginosa. This study comprised an epidemiological analysis of serum anti-PcrV titers in a cohort of Japanese adults. From April 2012 to March 2013, serum anti-PcrV titers of 198 volunteer participants undergoing anesthesia for scheduled surgeries were measured. The median, minimum and maximum serum anti-PcrV titers among the 198 participants were 4.09 nM, 1.01 nM and 113.81 nM, respectively. The maximum peaks in the histogram were within the anti-PcrV 2.00-4.99 nM titer range; values for 115 participants (58.1%) were within this range. Anti-PcrV titers were more than approximately three-fold greater (>12 nM) than the median value in 21 participants (10.6%). Ten-year interval age increases, history of treatment for traffic trauma, and a history of past surgery each showed statistically significant associations with higher anti-PcrV titers (i.e., >10 nM) than did the other factors assessed by binomial analysis. This study revealed a considerable variation in anti-PcrV titers in adult subjects without any obvious histories of infection with P. aeruginosa. PMID:26696420

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

    PubMed Central

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

    2014-01-01

    Clinical infections by Pseudomonas aeruginosa, a deadly Gram-negative, opportunistic pathogen of immunocompromised hosts, often involve the formation of antibiotic-resistant biofilms. Although biofilm formation has been extensively studied in vitro on glass or plastic surfaces, much less is known about biofilm formation at the epithelial barrier. We have previously shown that when added to the apical surface of polarized epithelial cells, P. aeruginosa rapidly forms cell-associated aggregates within 60 minutes of infection. By confocal microscopy we now show that cell-associated aggregates exhibit key characteristics of biofilms, including the presence of extracellular matrix and increased resistance to antibiotics compared to planktonic bacteria. Using isogenic mutants in the type III secretion system, we found that the translocon, but not the effectors themselves, were required for cell-associated aggregation on the surface of polarized epithelial cells and at early time points in a murine model of acute pneumonia. In contrast, the translocon was not required for aggregation on abiotic surfaces, suggesting a novel function for the type III secretion system during cell-associated aggregation. Supernatants from epithelial cells infected with wild-type bacteria or from cells treated with the pore-forming toxin streptolysin O could rescue aggregate formation in a type III secretion mutant, indicating that cell-associated aggregation requires one or more host cell factors. Our results suggest a previously unappreciated function for the type III translocon in the formation of P. aeruginosa biofilms at the epithelial barrier and demonstrate that biofilms may form at early time points of infection. PMID:25375398

  1. New Life for an Old Drug: the Anthelmintic Drug Niclosamide Inhibits Pseudomonas aeruginosa Quorum Sensing

    PubMed Central

    Imperi, Francesco; Massai, Francesco; Ramachandran Pillai, Cejoice; Longo, Francesca; Zennaro, Elisabetta; Rampioni, Giordano; Visca, Paolo

    2013-01-01

    The need for novel antibacterial strategies and the awareness of the importance of quorum sensing (QS) in bacterial infections have stimulated research aimed at identifying QS inhibitors (QSIs). However, clinical application of QSIs identified so far is still distant, likely due to their unsuitability for use in humans. A promising way to overcome this problem is searching for anti-QS side activity among the thousands of drugs approved for clinical use in the treatment of different diseases. Here, we applied this strategy to the search for QSIs, by screening a library of FDA-approved compounds for their ability to inhibit the QS response in the Gram-negative pathogen Pseudomonas aeruginosa. We found that the anthelmintic drug niclosamide strongly inhibits the P. aeruginosa QS response and production of acyl-homoserine lactone QS signal molecules. Microarray analysis showed that niclosamide affects the transcription of about 250 genes, with a high degree of target specificity toward the QS-dependent regulon. Phenotypic assays demonstrated that niclosamide suppresses surface motility and production of the secreted virulence factors elastase, pyocyanin, and rhamnolipids, and it reduces biofilm formation. In accordance with the strong antivirulence activity disclosed in vitro, niclosamide prevented P. aeruginosa pathogenicity in an insect model of acute infection. Besides the finding that an FDA-approved drug has a promising antivirulence activity against one of the most antibiotic-resistant bacterial pathogens, this work provides a proof of concept that a lateral anti-QS activity can be detected among drugs already used in humans, validating a new approach to identify QSIs that could easily move into clinical applications. PMID:23254430

  2. The Pseudomonas aeruginosa type III translocon is required for biofilm formation at the epithelial barrier.

    PubMed

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

    2014-11-01

    Clinical infections by Pseudomonas aeruginosa, a deadly Gram-negative, opportunistic pathogen of immunocompromised hosts, often involve the formation of antibiotic-resistant biofilms. Although biofilm formation has been extensively studied in vitro on glass or plastic surfaces, much less is known about biofilm formation at the epithelial barrier. We have previously shown that when added to the apical surface of polarized epithelial cells, P. aeruginosa rapidly forms cell-associated aggregates within 60 minutes of infection. By confocal microscopy we now show that cell-associated aggregates exhibit key characteristics of biofilms, including the presence of extracellular matrix and increased resistance to antibiotics compared to planktonic bacteria. Using isogenic mutants in the type III secretion system, we found that the translocon, but not the effectors themselves, were required for cell-associated aggregation on the surface of polarized epithelial cells and at early time points in a murine model of acute pneumonia. In contrast, the translocon was not required for aggregation on abiotic surfaces, suggesting a novel function for the type III secretion system during cell-associated aggregation. Supernatants from epithelial cells infected with wild-type bacteria or from cells treated with the pore-forming toxin streptolysin O could rescue aggregate formation in a type III secretion mutant, indicating that cell-associated aggregation requires one or more host cell factors. Our results suggest a previously unappreciated function for the type III translocon in the formation of P. aeruginosa biofilms at the epithelial barrier and demonstrate that biofilms may form at early time points of infection. PMID:25375398

  3. Genome-wide patterns of recombination in the opportunistic human pathogen Pseudomonas aeruginosa.

    PubMed

    Dettman, Jeremy R; Rodrigue, Nicolas; Kassen, Rees

    2015-01-01

    The bacterium Pseudomonas aeruginosa is a significant cause of acute nosocomial infections as well as chronic respiratory infections in patients with cystic fibrosis (CF). Recent reports of the intercontinental spread of a CF-specific epidemic strain, combined with high intrinsic levels of antibiotic resistance, have made this opportunistic pathogen an important public health concern. Strain-specific differences correlate with variation in clinical outcomes of infected CF patients, increasing the urgency to understand the evolutionary origin of genetic factors conferring important phenotypes that enable infection, virulence, or resistance. Here, we describe the genome-wide patterns of homologous and nonhomologous recombination in P. aeruginosa, and the extent to which the genomes are affected by these diversity-generating processes. Based on whole-genome sequence data from 32 clinical isolates of P. aeruginosa, we examined the rate and distribution of recombination along the genome, and its effect on the reconstruction of phylogenetic relationships. Multiple lines of evidence suggested that recombination was common and usually involves short stretches of DNA (200-300 bp). Although mutation was the main source of nucleotide diversity, the import of polymorphisms by homologous recombination contributed nearly as much. We also identified the genomic regions with frequent recombination, and the specific sequences of recombinant origin within epidemic strains. The functional characteristics of the genes contained therein were examined for potential associations with a pathogenic lifestyle or adaptation to the CF lung environment. A common link between many of the high-recombination genes was their functional affiliation with the cell wall, suggesting that the products of recombination may be maintained by selection for variation in cell-surface molecules that allows for evasion of the host immune system. PMID:25480685

  4. 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

  5. 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

  6. The prrF-Encoded Small Regulatory RNAs Are Required for Iron Homeostasis and Virulence of Pseudomonas aeruginosa

    PubMed Central

    Reinhart, Alexandria A.; Powell, Daniel A.; Nguyen, Angela T.; O'Neill, Maura; Djapgne, Louise; Wilks, Angela; Ernst, Robert K.

    2014-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that requires iron to cause infection, but it also must regulate the uptake of iron to avoid iron toxicity. The iron-responsive PrrF1 and PrrF2 small regulatory RNAs (sRNAs) are part of P. aeruginosa's iron regulatory network and affect the expression of at least 50 genes encoding iron-containing proteins. The genes encoding the PrrF1 and PrrF2 sRNAs are encoded in tandem in P. aeruginosa, allowing for the expression of a distinct, heme-responsive sRNA named PrrH that appears to regulate genes involved in heme metabolism. Using a combination of growth, mass spectrometry, and gene expression analysis, we showed that the ΔprrF1,2 mutant, which lacks expression of the PrrF and PrrH sRNAs, is defective for both iron and heme homeostasis. We also identified phuS, encoding a heme binding protein involved in heme acquisition, and vreR, encoding a previously identified regulator of P. aeruginosa virulence genes, as novel targets of prrF-mediated heme regulation. Finally, we showed that the prrF locus encoding the PrrF and PrrH sRNAs is required for P. aeruginosa virulence in a murine model of acute lung infection. Moreover, we showed that inoculation with a ΔprrF1,2 deletion mutant protects against future challenge with wild-type P. aeruginosa. Combined, these data demonstrate that the prrF-encoded sRNAs are critical regulators of P. aeruginosa virulence. PMID:25510881

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

    PubMed Central

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

    2010-01-01

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

  8. 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

  9. Role of outer membrane proteins in imipenem diffusion in Pseudomonas aeruginosa.

    PubMed

    Lian, Z; Tianjue, Y

    1999-03-01

    The present study identified the properties of porins in the outer membrane in Pseudomonas aeruginosa, and showed the role of outer membrane in determining imipenem diffusion in Pseudomonas aeruginosa. The molecular weight of the major outer membrane protein was analyzed by SDS-PAGE. The purification of the porins in Pseudomonas aeruginosa was achieved by DEAE ion-exchange HPLC. The purified outer membrane proteins were reconstituted with phosphatidylcholine and dicetylphosphate into membrane vesicles, and were tested by the liposomes swelling method for the diffusion of imipenem. The permeability assay showed that OprC (70 kD), OprD2 (46 kD), and OprE (43 kD) were the channel-forming proteins. But only OprD2 was thought to be the likely route of imipenem diffusion. PMID:12899386

  10. 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

  11. Draft Genome Sequence of Quorum-Sensing and Quorum-Quenching Pseudomonas aeruginosa Strain MW3a

    PubMed Central

    Wong, Cheng Siang; Yin, Wai-Fong; Chan, Xin Yue

    2014-01-01

    Pseudomonas aeruginosa has a broad range of habitation, from aquatic environments to human lungs. The coexistence of quorum-sensing and quorum-quenching activities occurs in P. aeruginosa strain MW3a. In this work, we present the draft genome sequence of P. aeruginosa MW3a, an interesting bacterium isolated from a marine environment. PMID:24744329

  12. Extracellular Ser/Thr/Tyr phosphorylated proteins of Pseudomonas aeruginosa PA14 strain.

    PubMed

    Ouidir, Tassadit; Jarnier, Frédérique; Cosette, Pascal; Jouenne, Thierry; Hardouin, Julie

    2014-09-01

    Protein phosphorylation on serine, threonine, and tyrosine is known to be involved in a wide variety of cellular processes, signal transduction, and bacterial virulence. We characterized, for the first time, the extracellular phosphoproteins of the Pseudomonas aeruginosa PA14 strain. We identified 28 phosphoproteins (59 phosphosites) including enzymes, with various phosphorylation sites, known as potent secreted virulence factors in P. aeruginosa. The high phosphorylation level of these virulence factors might reflect a relationship between Ser/Thr/Tyr phosphorylation and virulence. PMID:24965220

  13. 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

  14. Ubiquitin and Ubiquitin-Modified Proteins Activate the Pseudomonas aeruginosa T3SS Cytotoxin, ExoU

    PubMed Central

    Anderson, David M.; Schmalzer, Katherine M.; Sato, Hiromi; Casey, Monika; Terhune, Scott S.; Haas, Arthur L.; Feix, Jimmy B.; Frank, Dara W.

    2011-01-01

    Summary Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen that possesses a type III secretion system (T3SS) critical for evading innate immunity and establishing acute infections in compromised patients. Our research has focused on the structure-activity relationships of ExoU, the most toxic and destructive type III effector produced by P. aeruginosa. ExoU posseses phospholipase activity, which is detectable in vitro only when a eukaryotic cofactor is provided with membrane substrates. We report here that a subpopulation of ubiquitylated yeast SOD1 and other ubiquitylated mammalian proteins activate ExoU. Phospholipase activity was detected using purified ubiquitin of various chain lengths and linkage types; however, free monoubiquitin is sufficient in a genetically engineered dual expression system. The use of ubiquitin by a bacterial enzyme as an activator is unprecedented and represents a new aspect in the manipulation of the eukaryotic ubiquitin system to facilitate bacterial replication and dissemination. PMID:22040088

  15. High Density Waves of the Bacterium Pseudomonas aeruginosa in Propagating Swarms Result in Efficient Colonization of Surfaces

    PubMed Central

    Du, Huijing; Xu, Zhiliang; Anyan, Morgen; Kim, Oleg; Leevy, W. Matthew; Shrout, Joshua D.; Alber, Mark

    2012-01-01

    This work describes a new, to our knowledge, strategy of efficient colonization and community development where bacteria substantially alter their physical environment. Many bacteria move in groups, in a mode described as swarming, to colonize surfaces and form biofilms to survive external stresses, including exposure to antibiotics. One such bacterium is Pseudomonas aeruginosa, which is an opportunistic pathogen responsible for both acute and persistent infections in susceptible individuals, as exampled by those for burn victims and people with cystic fibrosis. Pseudomonas aeruginosa often, but not always, forms branched tendril patterns during swarming; this phenomena occurs only when bacteria produce rhamnolipid, which is regulated by population-dependent signaling called quorum sensing. The experimental results of this work show that P. aeruginosa cells propagate as high density waves that move symmetrically as rings within swarms toward the extending tendrils. Biologically justified cell-based multiscale model simulations suggest a mechanism of wave propagation as well as a branched tendril formation at the edge of the population that depends upon competition between the changing viscosity of the bacterial liquid suspension and the liquid film boundary expansion caused by Marangoni forces. Therefore, P. aeruginosa efficiently colonizes surfaces by controlling the physical forces responsible for expansion of thin liquid film and by propagating toward the tendril tips. The model predictions of wave speed and swarm expansion rate as well as cell alignment in tendrils were confirmed experimentally. The study results suggest that P. aeruginosa responds to environmental cues on a very short timescale by actively exploiting local physical phenomena to develop communities and efficiently colonize new surfaces. PMID:22947877

  16. [First outbreak report of VIM-1 metallo-beta-lactamase producing Pseudomonas aeruginosa in Japan].

    PubMed

    Miki, Kanji; Takegawa, Hiroshi; Etoh, Masaaki; Hayashi, Michio; Haruta, Tsunekazu; Yamane, Kunikazu; Arakawa, Yoshichika

    2010-11-01

    VIM-1 metallo-beta-lactamase (MBL) producing Pseudomonas aeruginosa was isolated from 35 Kobe City Medical Center General Hospital patients from September 2007 to July 2008. All but one were highly resistant to all beta-lactams, aminoglycoside, and fluoroquinolone, and one susceptible to amikacin. Strains negative to a disk diffusion screening test using sodium mercaptoacetate for detecting MBL numbered 35. PCR for MBL indicated all strains were positive for bla(VIWM-1). These strains were indistinguishable by pulsed-field gel electrophoresis, indicating an outbreak of infections caused by VIM-1 MBL producing Pseudomonas aeruginosa. After intervention to control contact, the outbreak was controlled. PMID:21226324

  17. Biodegradation of methyl parathion and endosulfan using Pseudomonas aeruginosa and Trichoderma viridae.

    PubMed

    Senthilkumar, S; Anthonisamy, A; Arunkumar, S; Sivakumari, V

    2011-01-01

    Microorganisms play an important role in the bioconversion and total breakdown of pesticides in the environment. This study was conducted to assess the pesticide degradation (endosulfan and methyl parathion) ability of the bacteria and fungi (Pseudomonas aeruginosa and Trichoderma viridae). The screening test conducted to reveal the ability to degrade endosulfan and methyl parathion shows that Trichoderma viridae was effective compared to Pseudomonas aeruginosa. The pesticide degradation was estimated by optical density method. Methyl parathion was highly degraded compared to endosulfan. This study clearly proves that pesticides and their residue degradation can be accelerated by employing microbes which can be effectively utilized both as biocontrol agent and soil cleanser. PMID:22324156

  18. 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

  19. SuhB Is a Regulator of Multiple Virulence Genes and Essential for Pathogenesis of Pseudomonas aeruginosa

    PubMed Central

    Li, Kewei; Xu, Chang; Jin, Yongxin; Sun, Ziyu; Liu, Chang; Shi, Jing; Chen, Gukui; Chen, Ronghao; Jin, Shouguang; Wu, Weihui

    2013-01-01

    ABSTRACT During initial colonization and chronic infection, pathogenic bacteria encounter distinct host environments. Adjusting gene expression accordingly is essential for the pathogenesis. Pseudomonas aeruginosa has evolved complicated regulatory networks to regulate different sets of virulence factors to facilitate colonization and persistence. The type III secretion system (T3SS) and motility are associated with acute infections, while biofilm formation and the type VI secretion system (T6SS) are associated with chronic persistence. To identify novel regulatory genes required for pathogenesis, we screened a P. aeruginosa transposon (Tn) insertion library and found suhB to be an essential gene for the T3SS gene expression. The expression of suhB was upregulated in a mouse acute lung infection model, and loss of suhB resulted in avirulence. Suppression of T3SS gene expression in the suhB mutant is linked to a defective translation of the T3SS master regulator, ExsA. Further studies demonstrated that suhB mutation led to the upregulation of GacA and its downstream small RNAs, RsmY and RsmZ, triggering T6SS expression and biofilm formation while inhibiting the T3SS. Our results demonstrate that an in vivo-inducible gene, suhB, reciprocally regulates genes associated with acute and chronic infections and plays an essential role in the pathogenesis of P. aeruginosa. PMID:24169572

  20. 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

  1. Post-translational modifications in Pseudomonas aeruginosa revolutionized by proteomic analysis.

    PubMed

    Ouidir, Tassadit; Jouenne, Thierry; Hardouin, Julie

    2016-06-01

    Pseudomonas aeruginosa is an opportunistic pathogen that causes severe infections in vulnerable individuals. It is known that post-translational modifications (PTMs) play a key role in bacterial physiology. Their characterization is still challenging and the recent advances in proteomics allow large-scale and high-throughput analyses of PTMs. Here, we provide an overview of proteomic data about the modified proteins in P. aeruginosa. We emphasize the significant contribution of proteomics in knowledge enhancement of PTMs (phosphorylation, N-acetylation and glycosylation) and we discuss their importance in P. aeruginosa physiology. PMID:26952777

  2. 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

  3. Differentiation of Pseudomonas aeruginosa pili based on sequence and B-cell epitope analyses.

    PubMed Central

    Castric, P A; Deal, C D

    1994-01-01

    The nucleotide sequences of three previously undescribed Pseudomonas aeruginosa pilin structural genes are presented. Comparisons of deduced pilin primary structure and flanking DNA sequence allowed placement of these and six previously published sequences into one of two groups. Epitope mapping, using overlapping immobilized peptides representing the pilin primary structure, with antipilin monoclonal antibodies revealed several B-cell determinants grouped near the carboxyl terminus of P. aeruginosa 1244 pilin. One determinant was found to reside near the pilin constant region. These determinants were found associated with the pili of 31 of 95 P. aeruginosa clinical isolates. PMID:7507890

  4. 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

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

    DOE PAGESBeta

    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

  6. 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.

  7. 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

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

    PubMed

    Keravec, Marlène; Mounier, Jérôme; Prestat, Emmanuel; Vallet, Sophie; Jansson, Janet K; Burgaud, Gaëtan; Rosec, Sylvain; Gouriou, Stéphanie; Rault, Gilles; Coton, Emmanuel; Barbier, Georges; Héry-Arnaud, Geneviève

    2015-01-01

    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. PMID:26266076

  9. 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

  10. Functional characterization of macrophage receptors for in vitro phagocytosis of unopsonized Pseudomonas aeruginosa.

    PubMed Central

    Speert, D P; Wright, S D; Silverstein, S C; Mah, B

    1988-01-01

    The phagocytic receptor for unopsonized Pseudomonas aeruginosa was characterized functionally using human monocyte-derived macrophages. Freshly isolated human peripheral blood monocytes were unable to ingest unopsonized P. aeruginosa; ingestion did not occur until the cells had been in culture for 2 d and it became maximal after 4 d. Macrophages plated on coverslips derivatized with anti-BSA IgG or with human gamma-globulin lost the capacity to phagocytose unopsonized P. aeruginosa, unopsonized zymosan, and EIgG but bound C3bi-coated erythrocytes normally. Each of the four human IgG subclasses and Fc fragments of anti-BSA IgG inhibited phagocytosis of both unopsonized P. aeruginosa and EIgG. Phagocytosis of P. aeruginosa and zymosan was markedly impaired and EIgG minimally inhibited if macrophages were plated on coverslips derivatized with mannan or when mannan was added to the phagocytosis buffer. Phagocytosis of P. aeruginosa and zymosan, and binding of EC3bi was dependent on the presence of divalent cations, but phagocytosis of EIgG was not. The macrophage phagocytic receptor for unopsonized P. aeruginosa was inactivated by proteolytic enzymes. Phagocytosis of P. aeruginosa was inhibited by D-mannose, L-fucose, and alpha methyl mannoside, but not by L-mannose, D-fucose, or D-glucose. The same sugars inhibited phagocytosis of unopsonized zymosan. We conclude that phagocytosis of unopsonized P. aeruginosa by human monocyte-derived macrophages is facilitated by mannose receptors. Images PMID:3138287

  11. 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

  12. 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

  13. 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

  14. Identification of a small molecule that simultaneously suppresses virulence and antibiotic resistance of Pseudomonas aeruginosa

    PubMed Central

    Guo, Qiaoyun; Wei, Yu; Xia, Bin; Jin, Yongxin; Liu, Chang; Pan, Xiaolei; Shi, Jing; Zhu, Feng; Li, Jinlong; Qian, Lei; Liu, Xinqi; Cheng, Zhihui; Jin, Shouguang; Lin, Jianping; Wu, Weihui

    2016-01-01

    The rising antibiotic resistance of bacteria imposes a severe threat on human health. Inhibition of bacterial virulence is an alternative approach to develop new antimicrobials. Molecules targeting antibiotic resistant enzymes have been used in combination with cognate antibiotics. It might be ideal that a molecule can simultaneously suppress virulence factors and antibiotic resistance. Here we combined genetic and computer-aided inhibitor screening to search for such molecules against the bacterial pathogen Pseudomonas aeruginosa. To identify target proteins that control both virulence and antibiotic resistance, we screened for mutants with defective cytotoxicity and biofilm formation from 93 transposon insertion mutants previously reported with increased antibiotic susceptibility. A pyrD mutant displayed defects in cytotoxicity, biofilm formation, quorum sensing and virulence in an acute mouse pneumonia model. Next, we employed a computer-aided screening to identify potential inhibitors of the PyrD protein, a dihydroorotate dehydrogenase (DHODase) involved in pyrimidine biosynthesis. One of the predicted inhibitors was able to suppress the enzymatic activity of PyrD as well as bacterial cytotoxicity, biofilm formation and antibiotic resistance. A single administration of the compound reduced the bacterial colonization in the acute mouse pneumonia model. Therefore, we have developed a strategy to identify novel treatment targets and antimicrobial molecules. PMID:26751736

  15. Identification of a small molecule that simultaneously suppresses virulence and antibiotic resistance of Pseudomonas aeruginosa.

    PubMed

    Guo, Qiaoyun; Wei, Yu; Xia, Bin; Jin, Yongxin; Liu, Chang; Pan, Xiaolei; Shi, Jing; Zhu, Feng; Li, Jinlong; Qian, Lei; Liu, Xinqi; Cheng, Zhihui; Jin, Shouguang; Lin, Jianping; Wu, Weihui

    2016-01-01

    The rising antibiotic resistance of bacteria imposes a severe threat on human health. Inhibition of bacterial virulence is an alternative approach to develop new antimicrobials. Molecules targeting antibiotic resistant enzymes have been used in combination with cognate antibiotics. It might be ideal that a molecule can simultaneously suppress virulence factors and antibiotic resistance. Here we combined genetic and computer-aided inhibitor screening to search for such molecules against the bacterial pathogen Pseudomonas aeruginosa. To identify target proteins that control both virulence and antibiotic resistance, we screened for mutants with defective cytotoxicity and biofilm formation from 93 transposon insertion mutants previously reported with increased antibiotic susceptibility. A pyrD mutant displayed defects in cytotoxicity, biofilm formation, quorum sensing and virulence in an acute mouse pneumonia model. Next, we employed a computer-aided screening to identify potential inhibitors of the PyrD protein, a dihydroorotate dehydrogenase (DHODase) involved in pyrimidine biosynthesis. One of the predicted inhibitors was able to suppress the enzymatic activity of PyrD as well as bacterial cytotoxicity, biofilm formation and antibiotic resistance. A single administration of the compound reduced the bacterial colonization in the acute mouse pneumonia model. Therefore, we have developed a strategy to identify novel treatment targets and antimicrobial molecules. PMID:26751736

  16. A gacS Deletion in Pseudomonas aeruginosa Cystic Fibrosis Isolate CHA Shapes Its Virulence

    PubMed Central

    Sall, Khady Mayebine; Casabona, Maria Guillermina; Bordi, Christophe; Huber, Philippe; de Bentzmann, Sophie; Attrée, Ina; Elsen, Sylvie

    2014-01-01

    Pseudomonas aeruginosa, a human opportunistic pathogen, is capable of provoking acute and chronic infections that are associated with defined sets of virulence factors. During chronic infections, the bacterium accumulates mutations that silence some and activate other genes. Here we show that the cystic fibrosis isolate CHA exhibits a unique virulence phenotype featuring a mucoid morphology, an active Type III Secretion System (T3SS, hallmark of acute infections), and no Type VI Secretion System (H1-T6SS). This virulence profile is due to a 426 bp deletion in the 3′ end of the gacS gene encoding an essential regulatory protein. The absence of GacS disturbs the Gac/Rsm pathway leading to depletion of the small regulatory RNAs RsmY/RsmZ and, in consequence, to expression of T3SS, while switching off the expression of H1-T6SS and Pel polysaccharides. The CHA isolate also exhibits full ability to swim and twitch, due to active flagellum and Type IVa pili. Thus, unlike the classical scheme of balance between virulence factors, clinical strains may adapt to a local niche by expressing both alginate exopolysaccharide, a hallmark of membrane stress that protects from antibiotic action, host defences and phagocytosis, and efficient T3S machinery that is considered as an aggressive virulence factor. PMID:24780952

  17. 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

  18. 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

  19. Relating the physical properties of Pseudomonas aeruginosa lipopolysaccharides to virulence by atomic force microscopy.

    PubMed

    Ivanov, Ivan E; Kintz, Erica N; Porter, Laura A; Goldberg, Joanna B; Burnham, Nancy A; Camesano, Terri A

    2011-03-01

    Lipopolysaccharides (LPS) are an important class of macromolecules that are components of the outer membrane of Gram-negative bacteria such as Pseudomonas aeruginosa. P. aeruginosa contains two different sugar chains, the homopolymer common antigen (A band) and the heteropolymer O antigen (B band), which impart serospecificity. The characteristics of LPS are generally assessed after isolation rather than in the context of whole bacteria. Here we used atomic force microscopy (AFM) to probe the physical properties of the LPS of P. aeruginosa strain PA103 (serogroup O11) in situ. This strain contains a mixture of long and very long polymers of O antigen, regulated by two different genes. For this analysis, we studied the wild-type strain and four mutants, ΔWzz1 (producing only very long LPS), ΔWzz2 (producing only long LPS), DΔM (with both the wzz1 and wzz2 genes deleted), and Wzy::GM (producing an LPS core oligosaccharide plus one unit of O antigen). Forces of adhesion between the LPS on these strains and the silicon nitride AFM tip were measured, and the Alexander and de Gennes model of steric repulsion between a flat surface and a polymer brush was used to calculate the LPS layer thickness (which we refer to as length), compressibility, and spacing between the individual molecules. LPS chains were longest for the wild-type strain and ΔWzz1, at 170.6 and 212.4 nm, respectively, and these values were not statistically significantly different from one another. Wzy::GM and DΔM have reduced LPS lengths, at 34.6 and 37.7 nm, respectively. Adhesion forces were not correlated with LPS length, but a relationship between adhesion force and bacterial pathogenicity was found in a mouse acute pneumonia model of infection. The adhesion forces with the AFM probe were lower for strains with LPS mutations, suggesting that the wild-type strain is optimized for maximal adhesion. Our research contributes to further understanding of the role of LPS in the adhesion and virulence of

  20. Anti-Pseudomonas aeruginosa IgY antibodies promote bacterial opsonization and augment the phagocytic activity of polymorphonuclear neutrophils.

    PubMed

    Thomsen, Kim; Christophersen, Lars; Jensen, Peter Østrup; Bjarnsholt, Thomas; Moser, Claus; Høiby, Niels

    2016-07-01

    Moderation of polymorphonuclear neutrophils (PMNs) as part of a critical defense against invading pathogens may offer a promising therapeutic approach to supplement the antibiotic eradication of Pseudomonas aeruginosa infection in non-chronically infected cystic fibrosis (CF) patients. We have observed that egg yolk antibodies (IgY) harvested from White leghorn chickens that target P. aeruginosa opsonize the pathogen and enhance the PMN-mediated respiratory burst and subsequent bacterial killing in vitro. The effects on PMN phagocytic activity were observed in different Pseudomonas aeruginosa strains, including clinical isolates from non-chronically infected CF patients. Thus, oral prophylaxis with anti-Pseudomonas aeruginosa IgY may boost the innate immunity against Pseudomonas aeruginosa in the CF setting by facilitating a rapid and prompt bacterial clearance by PMNs. PMID:26901841

  1. Multiple ecthyma gangrenosum in a healthy infant with community-acquired Pseudomonas aeruginosa sepsis.

    PubMed

    Wu, Chang-Teng; Huang, Jing-Long

    2010-10-01

    We report the case of a previously healthy 8-month-old infant girl with Pseudomonas aeruginosa sepsis who presented to a pediatric emergency department with multiple ecthyma gangrenosum. Skin manifestations are uncommon in Pseudomonas infection. Ecthyma gangrenosum is a rare, distinct skin disorder associated with potentially fatal underlying Pseudomonas sepsis. Although typically occurring in immunocompromised or neutropenic patients, it can occasionally affect otherwise healthy children. This case demonstrates the critical importance of the pediatrician's identification of ecthyma gangrenosum to give directed antipseudomonal therapy. PMID:20930597

  2. CLONING AND EXPRESSION OF THE CATA AND CATBC GENE CLUSTERS FROM PSEUDOMONAS AERUGINOSA PAO

    EPA Science Inventory

    A 9.9-kilobase (kb) BAMIII estriction endonuclease fragment encoding the catA and catBC gene clusters was selected from a gene bank of the Pseudomonas aeruginosa PAO1c chromosome. he catA, catB, and catC genes encode enzymes that catalyze consecutive reactions in the catechol bra...

  3. Production of Biologically Active Hydroxy Fatty Acids from Vegetable Oils by Pseudomonas aeruginosa PR3

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydroxy fatty acids have gained industrial attention because of their special properties such as higher viscosity and reactivity compared with other non-hydroxy fatty acids. The bacterial isolate Pseudomonas aeruginosa (PR3) had been reported to produce mono-, di-, and tri-hydroxy fatty acids from ...

  4. Draft Genome Assembly of Pseudomonas aeruginosa Quality Control Reference Strain Boston 41501.

    PubMed

    Minogue, T D; Daligault, H E; Davenport, K W; Broomall, S M; Bruce, D C; Chain, P S; Coyne, S R; Gibbons, H S; Jaissle, J; Chertkov, O; Freitas, T; Rosenzweig, C N; Xu, Y; Johnson, S L

    2014-01-01

    We present the scaffolded genome assembly of Pseudomonas aeruginosa Boston 41501, now publicly available in GenBank (JOVK00000000) in 10 contigs placed into a single scaffold. The 6.82-Mbp genome contains 66.1% G+C content and 6,295 coding sequences, including type 4 pilus and type 3 secretion system production genes. PMID:25278526

  5. Draft Genome Assembly of Pseudomonas aeruginosa Quality Control Reference Strain Boston 41501

    PubMed Central

    Minogue, T. D.; Daligault, H. E.; Davenport, K. W.; Broomall, S. M.; Bruce, D. C.; Chain, P. S.; Coyne, S. R.; Gibbons, H. S.; Jaissle, J.; Chertkov, O.; Freitas, T.; Rosenzweig, C. N.; Xu, Y.

    2014-01-01

    We present the scaffolded genome assembly of Pseudomonas aeruginosa Boston 41501, now publicly available in GenBank (JOVK00000000) in 10 contigs placed into a single scaffold. The 6.82-Mbp genome contains 66.1% G+C content and 6,295 coding sequences, including type 4 pilus and type 3 secretion system production genes. PMID:25278526

  6. 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

  7. 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

  8. [In-vitro antibiotic resistance of hospital and non-hospital strains of Pseudomonas aeruginosa].

    PubMed

    Ceddia, T; Marinucci, M C; Parravano, N

    1979-03-30

    The AA report about the resistence towards antibiotics of 42 stocks of Pseudomonas aeruginosa isolated from hospitalized patients and of 18 stocks isolated from non hospitalized patients. The most active antibiotics are Gentamicine, Neomicine and Streptomicine. Interestingly towards Tobramicine no resistence has been detected. The stocks isolated from hospitalized patients have generally shown a higher resistence. PMID:121701

  9. 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...

  10. Antimicrobial potential of bioconverted products of omega-3 fatty acids by Pseudomonas aeruginosa PR3

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioconverted omega-3 fatty acids, eicosapentaenoic acid (bEPA) and docosahexanoic acid (bDHA), obtained from the microbial conversion of non-bioconverted eicosapentaenoic and docosahexaenoic acids by Pseudomonas aeruginosa PR3 were evaluated for their antimicrobial potential. bEPA and bDHA at 5 µl/...

  11. Production of Biologically Active Hydroxy Fatty Acids by Pseudomonas aeruginosa PR3

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydroxy fatty acids (HFA) have gained important attentions because of their special properties such as higher viscosity and reactivity compared with other non-hydroxy fatty acids. Pseudomonas aeruginosa (PR3) had been reported to produce mono-, di-, and tri-hydroxy fatty acids from different unsatu...

  12. Pseudomonas aeruginosa septic shock associated with ecthyma gangrenosum in an infant with agammaglobulinemia.

    PubMed

    Almeida, João Fernando Lourenço de; Sztajnbok, Jaques; Troster, Eduardo Juan; Vaz, Flávio Adolfo Costa

    2002-01-01

    Ecthyma gangrenosum (EG) due to Pseudomonas aeruginosa is a rare and invasive infection that can be associated with agammaglobulinemia. The cornerstone of the treatment is based on prompt recognition with appropriate antibiotic coverage and intravenous immunoglobulin. The authors report a case of EG emphasizing the clinical and therapeutic aspects of this condition. PMID:12163911

  13. Ecthyma gangrenosum caused by Pseudomonas aeruginosa in a patient with astrocytoma treated with chemotherapy.

    PubMed

    De Vos, Filip Yves Francine Léon; Middelburg, Tom Alexander; Seynaeve, Caroline; de Jonge, Maja J A

    2010-02-01

    Ecthyma gangrenosum, presenting as embolic lesions caused by Pseudomonas aeruginosa infection, has distinct pathognomonic features and a high mortality rate in patients with bacteremia, but when recognized early is easily treated. In this case report we describe this disseminated infection in an adult patient treated with chemotherapy for an astrocytoma. PMID:20054603

  14. Draft Genome Sequences of 63 Pseudomonas aeruginosa Isolates Recovered from Cystic Fibrosis Sputum

    PubMed Central

    Spilker, Theodore

    2016-01-01

    Here, we report the draft genome sequences of 63 Pseudomonas aeruginosa isolates, recovered in culture of sputum from 15 individuals with cystic fibrosis (CF) receiving care in a single CF care center over a 13-year period. These sequences add value to studies of within-host evolution of bacterial pathogens during chronic infection. PMID:27103710

  15. Differential effects of Pseudomonas aeruginosa on biofilm formation by different strains of Staphylococcus epidermidis.

    PubMed

    Pihl, Maria; Davies, Julia R; Chávez de Paz, Luis E; Svensäter, Gunnel

    2010-08-01

    Pseudomonas aeruginosa and Staphylococcus epidermidis are common opportunistic pathogens associated with medical device-related biofilm infections. 16S rRNA-FISH and confocal laser scanning microscopy were used to study these two bacteria in dual-species biofilms. Two of the four S. epidermidis strains used were shown to form biofilms more avidly on polymer surfaces than the other two strains. In dual-species biofilms, the presence of P. aeruginosa reduced biofilm formation by S. epidermidis, although different clinical isolates differed in their susceptibility to this effect. The most resistant isolate coexisted with P. aeruginosa for up to 18 h and was also resistant to the effects of the culture supernatant from P. aeruginosa biofilms, which caused dispersal from established biofilms of other S. epidermidis strains. Thus, different strains of S. epidermidis differed in their capacity to withstand the action of P. aeruginosa, with some being better equipped than others to coexist in biofilms with P. aeruginosa. Our data suggest that where S. epidermidis and P. aeruginosa are present on abiotic surfaces such as medical devices, S. epidermidis biofilm formation can be inhibited by P. aeruginosa through two mechanisms: disruption by extracellular products, possibly polysaccharides, and, in the later stages, by cell lysis. PMID:20528934

  16. Inhalation with Fucose and Galactose for Treatment of Pseudomonas Aeruginosa in Cystic Fibrosis Patients

    PubMed Central

    Hauber, Hans-Peter; Schulz, Maria; Pforte, Almuth; Mack, Dietrich; Zabel, Peter; Schumacher, Udo

    2008-01-01

    Background: Colonisation of cystic fibrosis (CF) lungs with Pseudomonas aeruginosa is facilitated by two lectins, which bind to the sugar coat of the surface lining epithelia and stop the cilia beating. Objectives: We hypothesized that P. aeruginosa lung infection should be cleared by inhalation of fucose and galactose, which compete for the sugar binding site of the two lectins and thus inhibit the binding of P. aeruginosa. Methods: 11 adult CF patients with chronic infection with P. aeruginosa were treated twice daily with inhalation of a fucose/galactose solution for 21 days (4 patients only received inhalation, 7 patients received inhalation and intravenous antibiotics). Microbial counts of P. aeruginosa, lung function measurements, and inflammatory markers were determined before and after treatment. Results: The sugar inhalation was well tolerated and no adverse side effects were observed. Inhalation alone as well as combined therapy (inhalation and antibiotics) significantly decreased P. aeruginosa in sputum (P < 0.05). Both therapies also significantly reduced TNFα expression in sputum and peripheral blood cells (P < 0.05). No change in lung function measurements was observed. Conclusions: Inhalation of simple sugars is a safe and effective measure to reduce the P. aeruginosa counts in CF patients. This may provide an alternative therapeutical approach to treat infection with P. aeruginosa. PMID:19043609

  17. Genome macrorestriction analysis of sequential Pseudomonas aeruginosa isolates from bronchiectasis patients without cystic fibrosis.

    PubMed Central

    Hla, S W; Hui, K P; Tan, W C; Ho, B

    1996-01-01

    The respiratory tracts of bronchiectasis patients may be persistently colonized with Pseudomonas aeruginosa, despite intensive chemotherapy. The organism may undergo phenotypic changes in these patients, providing misleading typing results by conventional methods. We prospectively studied eight bronchiectasis patients without cystic fibrosis over a period of 1 year. A high microbial load of P. aeruginosa was found in 70% of sputum samples collected. Of these, 55 sequential P. aeruginosa isolates were characterized by a genotyping method, pulsed-field gel electrophoresis, to overcome the problem of differentiating the P. aeruginosa strains during chemotherapy. Genome macrorestriction fingerprinting patterns were analyzed after digestion with XbaI restriction endonuclease. Of the eight patients, six harbored a single dominant strain of P. aeruginosa, with an intrapatient macrorestriction similarity pattern range of 96 to 100%. The other two patients were infected with mixed bacterial isolates including P. aeruginosa. However, diversity was observed in the P. aeruginosa isolates from all eight patients, with a relatedness of only 55 to 65%. The study further strengthens the fact that pulsed-field gel electrophoresis can be used efficiently and effectively to differentiate P. aeruginosa strains in bronchiectasis patients without cystic fibrosis. PMID:8904417

  18. Effects of clinical isolates of Pseudomonas aeruginosa on Staphylococcus epidermidis biofilm formation.

    PubMed

    Pihl, Maria; Chávez de Paz, Luis E; Schmidtchen, Artur; Svensäter, Gunnel; Davies, Julia R

    2010-08-01

    Pseudomonas aeruginosa is often found in chronic infections, including cystic fibrosis lung infections and those related to chronic wounds and venous ulcers. At the latter sites, P. aeruginosa can be isolated together with Staphylococcus epidermidis, and we have therefore explored the effect of clinical isolates and laboratory strains of P. aeruginosa strains on colonization by S. epidermidis in dual-species biofilms. Biofilm formation was assayed using 16S rRNA FISH and confocal laser scanning microscopy. Among the six P. aeruginosa strains tested, one particular strain, denoted 14:2, exerted a significant inhibitory effect, and even after 6 h, S. epidermidis levels in dual-species biofilms were reduced by >85% compared with those without P. aeruginosa. Interestingly, strain 14:2 was found to be negative for classical virulence determinants including pyocyanin, elastase and alkaline protease. Therefore, we suggest that less virulent phenotypes of P. aeruginosa, which may develop over time in chronic infections, could counteract colonization by S. epidermidis, ensuring persistence and dominance by P. aeruginosa in the host micro-habitat. Further studies are required to explain the inhibitory effect on S. epidermidis, although extracellular polysaccharides produced by P. aeruginosa might play a role in this phenomenon. PMID:20579097

  19. Structure and Function of the Type III Secretion System of Pseudomonas aeruginosa

    PubMed Central

    Galle, Marlies; Carpentier, Isabelle; Beyaert, Rudi

    2012-01-01

    Pseudomonas aeruginosa is a dangerous pathogen particularly because it harbors multiple virulence factors. It causes several types of infection, including dermatitis, endocarditis, and infections of the urinary tract, eye, ear, bone, joints and, of particular interest, the respiratory tract. Patients with cystic fibrosis, who are extremely susceptible to Pseudomonas infections, have a bad prognosis and high mortality. An important virulence factor of P. aeruginosa, shared with many other gram-negative bacteria, is the type III secretion system, a hollow molecular needle that transfers effector toxins directly from the bacterium into the host cell cytosol. This complex macromolecular machine works in a highly regulated manner and can manipulate the host cell in many different ways. Here we review the current knowledge of the structure of the P. aeruginosa T3SS, as well as its function and recognition by the immune system. Furthermore, we describe recent progress in the development and use of therapeutic agents targeting the T3SS. PMID:23305368

  20. 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. PMID:26875795

  1. 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

  2. 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

  3. The Cyclic AMP-Vfr Signaling Pathway in Pseudomonas aeruginosa Is Inhibited by Cyclic Di-GMP

    PubMed Central

    Almblad, Henrik; Harrison, Joe J.; Rybtke, Morten; Groizeleau, Julie; Givskov, Michael; Parsek, Matthew R.

    2015-01-01

    ABSTRACT The opportunistic human pathogen Pseudomonas aeruginosa expresses numerous acute virulence factors in the initial phase of infection, and during long-term colonization it undergoes adaptations that optimize survival in the human host. Adaptive changes that often occur during chronic infection give rise to rugose small colony variants (RSCVs), which are hyper-biofilm-forming mutants that commonly possess mutations that increase production of the biofilm-promoting secondary messenger cyclic di-GMP (c-di-GMP). We show that RSCVs display a decreased production of acute virulence factors as a direct result of elevated c-di-GMP content. Overproduction of c-di-GMP causes a decrease in the transcription of virulence factor genes that are regulated by the global virulence regulator Vfr. The low level of Vfr-dependent transcription is caused by a low level of its coactivator, cyclic AMP (cAMP), which is decreased in response to a high level of c-di-GMP. Mutations that cause reversion of the RSCV phenotype concomitantly reactivate Vfr-cAMP signaling. Attempts to uncover the mechanism underlying the observed c-di-GMP-mediated lowering of cAMP content provided evidence that it is not caused by inhibition of adenylate cyclase production or activity and that it is not caused by activation of cAMP phosphodiesterase activity. In addition to the studies of the RSCVs, we present evidence that the deeper layers of wild-type P. aeruginosa biofilms have high c-di-GMP levels and low cAMP levels. IMPORTANCE Our work suggests that cross talk between c-di-GMP and cAMP signaling pathways results in downregulation of acute virulence factors in P. aeruginosa biofilm infections. Knowledge about this cross-regulation adds to our understanding of virulence traits and immune evasion by P. aeruginosa in chronic infections and may provide new approaches to eradicate biofilm infections. PMID:25897033

  4. Plasmid control of the Pseudomonas aeruginosa and Pseudomonas putida phenotypes and of linalool and p-cymene oxidation.

    PubMed Central

    de Smet, M J; Friedman, M B; Gunsalus, I C

    1989-01-01

    Two Pseudomonas strains (PpG777 and PaG158) were derived from the parent isolate Pseudomonas incognita (putida). Strain PpG777 resembles the parental culture in growth on linalool as a source of carbon and slight growth on p-cymene, whereas PaG158 grows well on p-cymene, but not on linalool or other terpenes tested, and has a P. aeruginosa phenotype. Curing studies indicate that linalool metabolism is controlled by an extrachromosomal element whose loss forms a stable strain PaG158 with the p-cymene growth and P. aeruginosa phenotype characters. The plasmid can be transferred by PpG777 to both P. putida and P. aeruginosa strains. Surprisingly, the latter assume the P. putida phenotype. We conclude that the genetic potential to oxidize p-cymene is inherent in PpG777 but expression is repressed. Similarly, this observation implies that support of linalool oxidation effectively conceals the P. aeruginosa character. PMID:2504698

  5. 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

  6. Whirlpool-associated folliculitis caused by Pseudomonas aeruginosa: report of an outbreak and review.

    PubMed

    Ratnam, S; Hogan, K; March, S B; Butler, R W

    1986-03-01

    An outbreak of folliculitis caused by Pseudomonas aeruginosa serotype O:7 occurred among the guests of a hotel in St. John's, Newfoundland, Canada, and the source of the infection was traced to the hotel whirlpool. Of 36 persons who used the whirlpool, 26 (72%) developed folliculitis within 1 to 5 days after exposure; the attack rate was significantly higher for children (90%) than for adults (50%). The rash characteristics were consistent with those of Pseudomonas folliculitis previously described (T. L. Gustafson, J. D. Band, R. H. Hutcheson, Jr., and W. Schaffner, Rev. Infect. Dis. 5:1-8, 1983). This is considered to be the first outbreak in which P. aeruginosa serotype O:7 has been incriminated. Published reports to date of outbreaks of Pseudomonas folliculitis associated with the use of whirlpools, hot tubs, swimming pools, etc., were reviewed. PMID:3082930

  7. Mode of action of the protein, SP127, which enhances the activity of macrolide antibiotics against Pseudomonas aeruginosa.

    PubMed

    Kikuchi, M; Nakao, Y

    1977-03-01

    Antibiotics, the activity of which enhanced against Pseudomonas aeruginosa by SP127, were restricted to the basic macrolide antibiotics such as erythromycin, maridomycin and oleandomycin, the neutral macrolide antibiotics such as lankamycin and lankacidin C, vancomycin and enramycin. Synergistic activity of SP127 with the above antibiotics was found against Pseudomonas aeruginosa and several strains of Escherichia coli, but not against Proteus vulgaris and macrolide-resistant Staphylococcus aureus. SP127 had extremely weak proteolytic but no lytic activity. From the isotopic experiments, the action of SP127 was partially attributed to the promotion of antibiotic penetration to cells of Pseudomonas aeruginosa. PMID:405356

  8. The Pseudomonas aeruginosa exoenzyme Y impairs endothelial cell proliferation and vascular repair following lung injury.

    PubMed

    Stevens, Trevor C; Ochoa, Cristhiaan D; Morrow, K Adam; Robson, Matthew J; Prasain, Nutan; Zhou, Chun; Alvarez, Diego F; Frank, Dara W; Balczon, Ron; Stevens, Troy

    2014-05-15

    Exoenzyme Y (ExoY) is a Pseudomonas aeruginosa toxin that is introduced into host cells through the type 3 secretion system (T3SS). Once inside the host cell cytoplasm, ExoY generates cyclic nucleotides that cause tau phosphorylation and microtubule breakdown. Microtubule breakdown causes interendothelial cell gap formation and tissue edema. Although ExoY transiently induces interendothelial cell gap formation, it remains unclear whether ExoY prevents repair of the endothelial cell barrier. Here, we test the hypothesis that ExoY intoxication impairs recovery of the endothelial cell barrier following gap formation, decreasing migration, proliferation, and lung repair. Pulmonary microvascular endothelial cells (PMVECs) were infected with P. aeruginosa strains for 6 h, including one possessing an active ExoY (PA103 exoUexoT::Tc pUCPexoY; ExoY(+)), one with an inactive ExoY (PA103ΔexoUexoT::Tc pUCPexoY(K81M); ExoY(K81M)), and one that lacks PcrV required for a functional T3SS (ΔPcrV). ExoY(+) induced interendothelial cell gaps, whereas ExoY(K81M) and ΔPcrV did not promote gap formation. Following gap formation, bacteria were removed and endothelial cell repair was examined. PMVECs were unable to repair gaps even 3-5 days after infection. Serum-stimulated growth was greatly diminished following ExoY intoxication. Intratracheal inoculation of ExoY(+) and ExoY(K81M) caused severe pneumonia and acute lung injury. However, whereas the pulmonary endothelial cell barrier was functionally improved 1 wk following ExoY(K81M) infection, pulmonary endothelium was unable to restrict the hyperpermeability response to elevated hydrostatic pressure following ExoY(+) infection. In conclusion, ExoY is an edema factor that chronically impairs endothelial cell barrier integrity following lung injury. PMID:24705722

  9. Anr and Its Activation by PlcH Activity in Pseudomonas aeruginosa Host Colonization and Virulence

    PubMed Central

    Jackson, Angelyca A.; Gross, Maegan J.; Daniels, Emily F.; Hampton, Thomas H.; Hammond, John H.; Vallet-Gely, Isabelle; Dove, Simon L.; Stanton, Bruce A.

    2013-01-01

    Pseudomonas aeruginosa hemolytic phospholipase C (PlcH) degrades phosphatidylcholine (PC), an abundant lipid in cell membranes and lung surfactant. A ΔplcHR mutant, known to be defective in virulence in animal models, was less able to colonize epithelial cell monolayers and was defective in biofilm formation on plastic when grown in lung surfactant. Microarray analyses found that strains defective in PlcH production had lower levels of Anr-regulated transcripts than the wild type. PC degradation stimulated the Anr regulon in an Anr-dependent manner under conditions where Anr activity was submaximal because of the presence of oxygen. Two PC catabolites, choline and glycine betaine (GB), were sufficient to stimulate Anr activity, and their catabolism was required for Anr activation. The addition of choline or GB to glucose-containing medium did not alter Anr protein levels, growth rates, or respiratory activity, and Anr activation could not be attributed to the osmoprotectant functions of GB. The Δanr mutant was defective in virulence in a mouse pneumonia model. Several lines of evidence indicate that Anr is important for the colonization of biotic and abiotic surfaces in both P. aeruginosa PAO1 and PA14 and that increases in Anr activity resulted in enhanced biofilm formation. Our data suggest that PlcH activity promotes Anr activity in oxic environments and that Anr activity contributes to virulence, even in the acute infection phase, where low oxygen tensions are not expected. This finding highlights the relationships among in vivo bacterial metabolism, the activity of the oxygen-sensitive regulator Anr, and virulence. PMID:23667230

  10. Mechanisms responsible for the emergence of carbapenem resistance in Pseudomonas aeruginosa

    PubMed Central

    Meletis, G; Exindari, M; Vavatsi, N; Sofianou, D; Diza, E

    2012-01-01

    Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen associated with a range of nosocomial infections. This microorganism is noted for its intrinsic resistance to antibiotics and for its ability to acquire genes encoding resistance determinants. Among the beta-lactam antibiotics, carbapenems with antipseudomonal activity are important agents for the therapy of infections due to P. aeruginosa. The development of carbapenem resistance among P. aeruginosa strains is multifactorial. Plasmid or integron-mediated carbapenemases, increased expression of efflux systems, reduced porin expression and increased chromosomal cephalosporinase activity have all been defined as contributory factors. Phenotypic tests and molecular techniques are used for the characterization of the resistance determinants. The isolation of carbapenem resistant strains is alarming and requires the implementation of strict infection control measures in order to prevent the spread of carbapenemase encoding genes to unrelated clones or to other bacterial species. PMID:23935307

  11. 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

  12. 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

  13. 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

  14. (1)H NMR spectroscopy in the diagnosis of Pseudomonas aeruginosa-induced urinary tract infection.

    PubMed

    Gupta, Ashish; Dwivedi, Mayank; Nagana Gowda, G A; Ayyagari, Archana; Mahdi, A A; Bhandari, M; Khetrapal, C L

    2005-08-01

    The utility of (1)H NMR spectroscopy is suggested and demonstrated for the diagnosis of Pseudomonas aeruginosa in urinary tract infection (UTI). The specific property of P. aeruginosa of metabolizing nicotinic acid to 6-hydroxynicotinic acid (6-OHNA) is exploited. The quantity of 6-OHNA produced correlates well with the viable bacterial count. Other common bacteria causing UTI such as Escherichia coli, Klebsiella pneumonia, Enterobacter aerogenes, Acinetobacter baumanii, Proteus mirabilis, Citrobacter frundii, Enterococcus faecalis, Streptococcus gp B and Staphylococcus aureus do not metabolize nicotinic acid under similar conditions. The method provides a single-step documentation of P. aeruginosa qualitatively as well as quantitatively. The NMR method is demonstrated on urine samples from 30 patients with UTI caused by P. aeruginosa. PMID:15759292

  15. 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

  16. Anti-quorum sensing activity of selected sponge extracts: a case study of Pseudomonas aeruginosa.

    PubMed

    Pejin, Boris; Talevska, Aleksandra; Ciric, Ana; Glamoclija, Jasmina; Nikolic, Milos; Talevski, Trajce; Sokovic, Marina

    2014-01-01

    The anti-quorum sensing activities towards the bacterium Pseudomonas aeruginosa PA01 (pyocyanin production, biofilm formation and twitching and flagella motility) of two crude extracts (methanol and acetone) of the freshwater sponge Ochridaspongia rotunda (Arndt, 1937) were evaluated in vitro for the first time. Both extracts demonstrated P. aeruginosa pyocyanin inhibitory activity, reducing its production for 49.90% and 42.44%, respectively. In addition, they both showed higher anti-biofilm activity (48.29% and 53.99%, respectively) than ampicillin (30.84%). Finally, O. rotunda extracts effectively reduced twitching and flagella motility of P. aeruginosa. Taken all together, these results suggest that endemic sponge species from the oldest lake in Europe may offer novel bioactive natural products with promising medicinal potential towards P. aeruginosa infections. PMID:25039944

  17. Pseudomonas aeruginosa infection in cystic fibrosis: pathophysiological mechanisms and therapeutic approaches.

    PubMed

    Lund-Palau, Helena; Turnbull, Andrew R; Bush, Andrew; Bardin, Emmanuelle; Cameron, Loren; Soren, Odel; Wierre-Gore, Natasha; Alton, Eric W F W; Bundy, Jacob G; Connett, Gary; Faust, Saul N; Filloux, Alain; Freemont, Paul; Jones, Andy; Khoo, Valerie; Morales, Sandra; Murphy, Ronan; Pabary, Rishi; Simbo, Ameze; Schelenz, Silke; Takats, Zoltan; Webb, Jeremy; Williams, Huw D; Davies, Jane C

    2016-06-01

    Pseudomonas aeruginosa is a remarkably versatile environmental bacterium with an extraordinary capacity to infect the cystic fibrosis (CF) lung. Infection with P. aeruginosa occurs early, and although eradication can be achieved following early detection, chronic infection occurs in over 60% of adults with CF. Chronic infection is associated with accelerated disease progression and increased mortality. Extensive research has revealed complex mechanisms by which P. aeruginosa adapts to and persists within the CF airway. Yet knowledge gaps remain, and prevention and treatment strategies are limited by the lack of sensitive detection methods and by a narrow armoury of antibiotics. Further developments in this field are urgently needed in order to improve morbidity and mortality in people with CF. Here, we summarize current knowledge of pathophysiological mechanisms underlying P. aeruginosa infection in CF. Established treatments are discussed, and an overview is offered of novel detection methods and therapeutic strategies in development. PMID:27175979

  18. 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

  19. RT-PCR detection of exotoxin genes expression in multidrug resistant Pseudomonas aeruginosa.

    PubMed

    Tartor, Y H; El-Naenaeey, E Y

    2016-01-01

    Pseudomonas aeruginosa (PA) is an opportunistic pathogen responsible for causing a wide variety of acute and chronic infections with significant levels of morbidity and mortality. These infections are very hard to eradicate because of the expression of numerous virulence factors and the intrinsic resistance against antibiotics. Herein, this study analyzed antimicrobial susceptibility of PA isolated from broiler chickens and cattle as well as expression of five significant exotoxin genes (exoU, exoS, toxA, lasB, and phzM) and ecfX as internal control. Genomic DNA was amplified employing oprL gene for species specific detection of PA. The highest resistance was found to ampicillin, erythromycin, followed by, chloramphenicol, trimethoprim/ sulfamethoxazole and tetracycline, intermediately sensitive to ceftazidime, cefoperazone, and highly sensitive to gentamicin, levofloxacin, imipenem, ciprofloxacin and colistin. It appears that exoU+ and increased resistance to SXT may be co-selected traits. Vast majority of PA isolates expressed exoS (78.6%), exoU (71.4%) and both in more virulent strains. The ubiquity of toxA, lasB, exoU and exoS among PA clinical isolates is consistent with an important role for these virulence factors in chicken respiratory diseases and cattle mastitis that can be highlighted as potential therapeutic targets for treatment of infections caused by heterogeneous and resistant PA strains. PMID:26828988

  20. RESULTS OF MONITORING METALLO-BETA-LACTAMASE-PRODUCING STRAINS OF PSEUDOMONAS AERUGINOSA IN A MULTI-PROFILE HOSPITAL.

    PubMed

    Shamaeva, S K; Portnyagina, U S; Edelstein, M V; Kuzmina, A A; Maloguloval, S; Varfolomeeva, N A

    2015-01-01

    The authors present the results of long-term monitoring of metallo-beta-lactamase (MBL) producing strains of Pseudomonas aeruginosa in the Republican Hospital No 2 of Yakutsk, Russian Federation. Hospitals across Russia, as well as the rest of the world, face a rapid appearance and a virtually unchecked spread of multiresistant and panresistant nosocomial pathogens. Especially prevalent are multidrug-resistant isolates of P. aeruginosa, most often found among the patients of intensive care and intensive therapy units, as well as surgery departments. The aim of this study is to investigate the prevalence of metallo-beta-lactamase-producing strains of P. aeruginosa in a multi-profile hospital. 2,135 isolates of P. aeruginosa were studied, collected during a time span of seven years (2008-2014) from clinical specimens of hospitalised patients in acute surgery, purulent surgery, neurosurgery, otolaryngology, coloproctology departments, intensive care and intensive therapy, burn units, as well as intensive care unit for patients with acute cerebrovascular accidents and coronary care unit. Strains were identified and re-identified using established methods, NEFERMtest 24 (MICROLATEST) biochemical microtest and API (bioMerieux) test systems were used. For all carbapenem-resistant strains a phenotype screening for MBL was performed using the double-disks method with EDTA. In order to identify VIM-type and IMP-type MBL genes a real-time multiplex polymerase chain reaction was used. Among the investigated strains the largest number of P. aeruginosa - 35.6% (761 isolates) was found in patients at intensive care and intensive therapy units. Clonal expansion of extensively drug-resistant strain P. aeruginosa ST235 (VIM-2) was determined, the resistance mechanism of which is connected to MBL. Sensitivity determination of MBL-producing isolates of P. aeruginosa has shown that isolated strains have a high level of resistance (100%) to all tested antibacterial agents: piperacillin

  1. Antigenic relationship between the common antigen (OEP) of Pseudomonas aeruginosa and Vibrio cholerae.

    PubMed Central

    Hirao, Y; Homma, J Y

    1978-01-01

    Antibodies were found by the OEP-passive hemagglutination test to cross-react with the common antigen (OEP) of Pseudomonas aeruginosa in sera of rabbits immunized with two serotype (Inaba and Ogawa) strains of Vibrio cholerae. The titer in the OEP-passive hemagglutination reaction rose later than did the agglutinin titer and reached a peak of 640 to 1,280. The titers of OEP antibody formation in rabbits immunized with V. cholerae were almost the same as that of P. aeruginosa. The common antigen of P. aeruginosa was confirmed to exist serologically in both strains of V. cholerae as determined by the indirect fluorescent antibody test and the agar gel precipitin test. Passive immunization with the V. cholerae immune rabbit serum significantly protected mice against P. aeruginosa infection. Purified antibodies cross-reacting with the OEP of P. aeruginosa derived from the V. cholerae immune rabbit sera by OEP-coupled affinity chromatography protected mice against P. aeruginosa infection as compared with the control group, which was injected with 100 microgram of immunoglobin G not containing OEP antibody. The purified antibodies (2.5 microgram per mouse) protected animals challenged with approximately 10,000 50% lethal doses in the control group. Consequently, the common antigen (OEP) of P. aeruginosa proved to be a common antigen of V. cholerae both serologically and in possessing infection protective properties. PMID:75846

  2. 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

  3. The complex interplay of iron, biofilm formation, and mucoidy affecting antimicrobial resistance of Pseudomonas aeruginosa.

    PubMed

    Oglesby-Sherrouse, Amanda G; Djapgne, Louise; Nguyen, Angela T; Vasil, Adriana I; Vasil, Michael L

    2014-04-01

    Pseudomonas aeruginosa is a Gram-negative opportunistic bacterial pathogen that is refractory to a variety of current antimicrobial therapeutic regimens. Complicating treatment for 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, nonsiderophore 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 subinhibitory 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

  4. Enhanced Clearance of Pseudomonas aeruginosa by Peroxisome Proliferator-Activated Receptor Gamma.

    PubMed

    Bedi, Brahmchetna; Yuan, Zhihong; Joo, Myungsoo; Zughaier, Susu M; Goldberg, Joanna B; Arbiser, Jack L; Hart, C Michael; Sadikot, Ruxana T

    2016-07-01

    The pathogenic profile of Pseudomonas aeruginosa is related to its ability to secrete a variety of virulence factors. Quorum sensing (QS) is a mechanism wherein small diffusible molecules, specifically acyl-homoserine lactones, are produced by P. aeruginosa to promote virulence. We show here that macrophage clearance of P. aeruginosa (PAO1) is enhanced by activation of the nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPARγ). Macrophages treated with a PPARγ agonist (pioglitazone) showed enhanced phagocytosis and bacterial killing of PAO1. It is known that PAO1 QS molecules are inactivated by PON-2. QS molecules are also known to inhibit activation of PPARγ by competitively binding PPARγ receptors. In accord with this observation, we found that infection of macrophages with PAO1 inhibited expression of PPARγ and PON-2. Mechanistically, we show that PPARγ induces macrophage paraoxonase 2 (PON-2), an enzyme that degrades QS molecules produced by P. aeruginosa Gene silencing studies confirmed that enhanced clearance of PAO1 in macrophages by PPARγ is PON-2 dependent. Further, we show that PPARγ agonists also enhance clearance of P. aeruginosa from lungs of mice infected with PAO1. Together, these data demonstrate that P. aeruginosa impairs the ability of host cells to mount an immune response by inhibiting PPARγ through secretion of QS molecules. These studies define a novel mechanism by which PPARγ contributes to the host immunoprotective effects during bacterial infection and suggest a role for PPARγ immunotherapy for P. aeruginosa infections. PMID:27091928

  5. Pseudomonas aeruginosa Triggers Macrophage Autophagy To Escape Intracellular Killing by Activation of the NLRP3 Inflammasome

    PubMed Central

    Deng, Qiuchan; Wang, Yi; Zhang, Yuanqing; Li, Meiyu; Li, Dandan; Huang, Xi; Wu, Yongjian; Pu, Jieying

    2015-01-01

    Assembly of the inflammasome has recently been identified to be a critical event in the initiation of inflammation. However, its role in bacterial killing remains unclear. Our study demonstrates that Pseudomonas aeruginosa infection induces the assembly of the NLRP3 inflammasome and the sequential secretion of caspase1 and interleukin-1β (IL-1β) in human macrophages. More importantly, activation of the NLRP3 inflammasome reduces the killing of P. aeruginosa in human macrophages, without affecting the generation of antimicrobial peptides, reactive oxygen species, and nitric oxide. In addition, our results demonstrate that P. aeruginosa infection increases the amount of the LC3-II protein and triggers the formation of autophagosomes in human macrophages. The P. aeruginosa-induced autophagy was enhanced by overexpression of NLRP3, ASC, or caspase1 but was reduced by knockdown of these core molecules of the NLRP3 inflammasome. Treatment with IL-1β enhanced autophagy in human macrophages. More importantly, IL-1β decreased the macrophage-mediated killing of P. aeruginosa, whereas knockdown of ATG7 or Beclin1 restored the IL-1β-mediated suppression of bacterial killing. Collectively, our study explores a novel mechanism employed by P. aeruginosa to escape from phagocyte killing and may provide a better understanding of the interaction between P. aeruginosa and host immune cells, including macrophages. PMID:26467446

  6. Modulation of Pseudomonas aeruginosa adherence to the corneal surface by mucus.

    PubMed Central

    Fleiszig, S M; Zaidi, T S; Ramphal, R; Pier, G B

    1994-01-01

    To gain access to the corneal epithelium and cause infections keratitis, bacterial pathogens must first interact with ocular surface factors that could affect bacterial adherence. In this study, we demonstrated that the mucus layer, and, in particular, the mucin fraction of mucus, modulated adherence to intact corneal epithelium of Pseudomonas aeruginosa but not that of Staphylococcus aureus or Streptococcus pyogenes. Removal of endogenous mucus from rat or rabbit eyes increased the adherence of P. aeruginosa by 3- to 10-fold. Ocular mucus obtained from rat eyes, porcine stomach mucin, or bovine submaxillary gland mucin inhibited adherence of P. aeruginosa to uninjured corneal epithelium. The mucin fraction of ocular mucus, purified by ultracentrifugation, was found to contain the inhibitory activity, and inhibition was demonstrated at concentrations of mucin as low as 35 micrograms/ml. Ocular mucin was the only material tested that inhibited adherence of P. aeruginosa to an injured cornea. However, the binding of P. aeruginosa to immobilized substrates in vitro did not predict which fraction would possess antiadherence activity: bacteria bound well to whole ocular mucus, mucin, the nonmucin fraction of ocular mucus, and dilute human tears as well as to porcine stomach mucin and bovine submaxillary gland mucin. The effectiveness of the mucin fraction of ocular mucus at inhibiting the binding of P. aeruginosa to the cornea implies that this material is a barrier that protects the surface of the eye from P. aeruginosa adherence. PMID:8168942

  7. Blue Light Rescues Mice from Potentially Fatal Pseudomonas aeruginosa Burn Infection: Efficacy, Safety, and Mechanism of Action

    PubMed Central

    Dai, Tianhong; Gupta, Asheesh; Huang, Ying-Ying; Yin, Rui; Murray, Clinton K.; Vrahas, Mark S.; Sherwood, Margaret E.; Tegos, George P.

    2013-01-01

    Blue light has attracted increasing attention due to its intrinsic antimicrobial effect without the addition of exogenous photosensitizers. However, the use of blue light for wound infections has not been established yet. In this study, we demonstrated the efficacy of blue light at 415 nm for the treatment of acute, potentially lethal Pseudomonas aeruginosa burn infections in mice. Our in vitro studies demonstrated that the inactivation rate of P. aeruginosa cells by blue light was approximately 35-fold higher than that of keratinocytes (P = 0.0014). Transmission electron microscopy revealed blue light-mediated intracellular damage to P. aeruginosa cells. Fluorescence spectroscopy suggested that coproporphyrin III and/or uroporphyrin III are possibly the intracellular photosensitive chromophores associated with the blue light inactivation of P. aeruginosa. In vivo studies using an in vivo bioluminescence imaging technique and an area-under-the-bioluminescence-time-curve (AUBC) analysis showed that a single exposure of blue light at 55.8 J/cm2, applied 30 min after bacterial inoculation to the infected mouse burns, reduced the AUBC by approximately 100-fold in comparison with untreated and infected mouse burns (P < 0.0001). Histological analyses and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assays indicated no significant damage in the mouse skin exposed to blue light at the effective antimicrobial dose. Survival analyses revealed that blue light increased the survival rate of the infected mice from 18.2% to 100% (P < 0.0001). In conclusion, blue light therapy might offer an effective and safe alternative to conventional antimicrobial therapy for P. aeruginosa burn infections. PMID:23262998

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

    PubMed Central

    2011-01-01

    Background Our previously published reports have described an effective biocontrol agent named Pseudomonas sp. M18 as its 16S rDNA sequence and several regulator genes share homologous sequences with those of P. aeruginosa, but there are several unusual phenotypic features. This study aims to explore its strain specific genomic features and gene expression patterns at different temperatures. Results The complete M18 genome is composed of a single chromosome of 6,327,754 base pairs containing 5684 open reading frames. Seven genomic islands, including two novel prophages and five specific non-phage islands were identified besides the conserved P. aeruginosa core genome. Each prophage contains a putative chitinase coding gene, and the prophage II contains a capB gene encoding a putative cold stress protein. The non-phage genomic islands contain genes responsible for pyoluteorin biosynthesis, environmental substance degradation and type I and III restriction-modification systems. Compared with other P. aeruginosa strains, the fewest number (3) of insertion sequences and the most number (3) of clustered regularly interspaced short palindromic repeats in M18 genome may contribute to the relative genome stability. Although the M18 genome is most closely related to that of P. aeruginosa strain LESB58, the strain M18 is more susceptible to several antimicrobial agents and easier to be erased in a mouse acute lung infection model than the strain LESB58. The whole M18 transcriptomic analysis indicated that 10.6% of the expressed genes are temperature-dependent, with 22 genes up-regulated at 28°C in three non-phage genomic islands and one prophage but none at 37°C. Conclusions The P. aeruginosa strain M18 has evolved its specific genomic structures and temperature dependent expression patterns to meet the requirement of its fitness and competitiveness under selective pressures imposed on the strain in rhizosphere niche. PMID:21884571

  9. Blue light rescues mice from potentially fatal Pseudomonas aeruginosa burn infection: efficacy, safety, and mechanism of action.

    PubMed

    Dai, Tianhong; Gupta, Asheesh; Huang, Ying-Ying; Yin, Rui; Murray, Clinton K; Vrahas, Mark S; Sherwood, Margaret E; Tegos, George P; Hamblin, Michael R

    2013-03-01

    Blue light has attracted increasing attention due to its intrinsic antimicrobial effect without the addition of exogenous photosensitizers. However, the use of blue light for wound infections has not been established yet. In this study, we demonstrated the efficacy of blue light at 415 nm for the treatment of acute, potentially lethal Pseudomonas aeruginosa burn infections in mice. Our in vitro studies demonstrated that the inactivation rate of P. aeruginosa cells by blue light was approximately 35-fold higher than that of keratinocytes (P = 0.0014). Transmission electron microscopy revealed blue light-mediated intracellular damage to P. aeruginosa cells. Fluorescence spectroscopy suggested that coproporphyrin III and/or uroporphyrin III are possibly the intracellular photosensitive chromophores associated with the blue light inactivation of P. aeruginosa. In vivo studies using an in vivo bioluminescence imaging technique and an area-under-the-bioluminescence-time-curve (AUBC) analysis showed that a single exposure of blue light at 55.8 J/cm(2), applied 30 min after bacterial inoculation to the infected mouse burns, reduced the AUBC by approximately 100-fold in comparison with untreated and infected mouse burns (P < 0.0001). Histological analyses and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assays indicated no significant damage in the mouse skin exposed to blue light at the effective antimicrobial dose. Survival analyses revealed that blue light increased the survival rate of the infected mice from 18.2% to 100% (P < 0.0001). In conclusion, blue light therapy might offer an effective and safe alternative to conventional antimicrobial therapy for P. aeruginosa burn infections. PMID:23262998

  10. Recycling of peptidyl-tRNAs by peptidyl-tRNA hydrolase counteracts azithromycin-mediated effects on Pseudomonas aeruginosa.

    PubMed

    Gödeke, Julia; Pustelny, Christian; Häussler, Susanne

    2013-04-01

    Acute and chronic infections caused by the opportunistic pathogen Pseudomonas aeruginosa pose a serious threat to human health worldwide, and its increasing resistance to antibiotics requires alternative treatments that are more effective than available strategies. Clinical studies have clearly demonstrated that cystic fibrosis (CF) patients with chronic P. aeruginosa infections benefit from long-term low-dose azithromycin (AZM) treatment. Immunomodulating activity, the impact of AZM on the expression of quorum-sensing-dependent virulence factors, type three secretion, and motility in P. aeruginosa seem to contribute to the therapeutic response. However, to date, the molecular mechanisms underlying these AZM effects have remained elusive. Our data indicate that the AZM-mediated phenotype is caused by a depletion of the intracellular pools of tRNAs available for protein synthesis. Overexpression of the P. aeruginosa peptidyl-tRNA hydrolase, which recycles the tRNA from peptidyl-tRNA drop-off during translation, counteracted the effects of AZM on stationary-phase cell killing, cytotoxicity, and the production of rhamnolipids and partially restored swarming motility. Intriguingly, the exchange of a rare for a frequent codon in rhlR also explicitly diminished the AZM-mediated decreased production of rhamnolipids. These results indicate that depletion of the tRNA pools by AZM seems to affect the translation of genes that use rare aminoacyl-tRNA isoacceptors to a great extent and might explain the selective activity of AZM on the P. aeruginosa proteome and possibly also on the protein expression profiles of other bacterial pathogens. PMID:23318806

  11. 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

  12. 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.

  13. 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

  14. Within-host evolution of Pseudomonas aeruginosa reveals adaptation toward iron acquisition from hemoglobin.

    PubMed

    Marvig, Rasmus Lykke; Damkiær, Søren; Khademi, S M Hossein; Markussen, Trine M; Molin, Søren; Jelsbak, Lars

    2014-01-01

    ABSTRACT Pseudomonas aeruginosa airway infections are a major cause of mortality and morbidity of cystic fibrosis (CF) patients. In order to persist, P. aeruginosa depends on acquiring iron from its host, and multiple different iron acquisition systems may be active during infection. This includes the pyoverdine siderophore and the Pseudomonas heme utilization (phu) system. While the regulation and mechanisms of several iron-scavenging systems are well described, it is not clear whether such systems are targets for selection during adaptation of P. aeruginosa to the host environment. Here we investigated the within-host evolution of the transmissible P. aeruginosa DK2 lineage. We found positive selection for promoter mutations leading to increased expression of the phu system. By mimicking conditions of the CF airways in vitro, we experimentally demonstrate that increased expression of phuR confers a growth advantage in the presence of hemoglobin, thus suggesting that P. aeruginosa evolves toward iron acquisition from hemoglobin. To rule out that this adaptive trait is specific to the DK2 lineage, we inspected the genomes of additional P. aeruginosa lineages isolated from CF airways and found similar adaptive evolution in two distinct lineages (DK1 and PA clone C). Furthermore, in all three lineages, phuR promoter mutations coincided with the loss of pyoverdine production, suggesting that within-host adaptation toward heme utilization is triggered by the loss of pyoverdine production. Targeting heme utilization might therefore be a promising strategy for the treatment of P. aeruginosa infections in CF patients. IMPORTANCE Most bacterial pathogens depend on scavenging iron within their hosts, which makes the battle for iron between pathogens and hosts a hallmark of infection. Accordingly, the ability of the opportunistic pathogen Pseudomonas aeruginosa to cause chronic infections in cystic fibrosis (CF) patients also depends on iron-scavenging systems. While

  15. Protective efficacy of a peptide derived from a potential adhesin of Pseudomonas aeruginosa against corneal infection.

    PubMed

    Yuan, Qing; Wu, Yuting; Wang, Yiqiang; Chen, Lin; Qu, Mingli; Duan, Kangmin; Zhao, Ge

    2016-02-01

    Dissecting the interactions between Pseudomonas aeruginosa and corneal cells is important to identify a novel target for prevention and treatment of Pseudomonas keratitis. The current study began with a peptide identified by phage display, and was to investigate the protective efficacy against P. aeruginosa infection in cornea. The original peptide Pc-E, with high homology to a hypothetical membrane protein (HmpA) in P. aeruginosa, and the derived peptide Pc-EP, with the same sequence as a region in HmpA, were synthesized. Peptide Pc-EP could directly bind to HCEC, stronger than Pc-E, and specifically activate toll-like receptor 5, and thereby significantly induce the production of pro-inflammatory factors, such as IL-1β, IL-6, IFN-γ and IL-17. Moreover, Pc-EP could act as an antagonist to inhibit the adhesion of wild-type P. aeruginosa to HCEC and mouse corneas. No inhibitory effect was observed on the adhesion of the strain loss of HmpA. When compared to the wild-type strain, the adhesion of the hmpA mutant to corneal cells was significantly decreased. Treatment of infected mouse corneas with Pc-EP before infection significantly decreased the bacterial load in the cornea and attenuated the corneal pathology. These results indicate that Pc-EP can be a useful prophylactic agent for P. aeruginosa keratitis. PMID:26500187

  16. 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

  17. New Small Plasmid Harboring blaKPC-2 in Pseudomonas aeruginosa.

    PubMed

    Galetti, Renata; Andrade, Leonardo Neves; Chandler, Michael; Varani, Alessandro de Mello; Darini, Ana Lúcia Costa

    2016-05-01

    The aim of this study was to characterize the genetic context of blaKPC-2 in Pseudomonas aeruginosa sequence type 244 from Brazil. The blaKPC-2 gene was detected in a new small plasmid, pBH6. Complete sequencing revealed that pBH6 was 3,652 bp long and included the Tn3 resolvase and Tn3 inverted repeat (IR), a partial copy of ISKpn6, and a putative ori region but no rep genes. pBH6 replicated stably into Escherichia coli strain DH10B and P. aeruginosa strain PAO. PMID:26953192

  18. Proteomic profiling of lysine acetylation in Pseudomonas aeruginosa reveals the diversity of acetylated proteins.

    PubMed

    Ouidir, Tassadit; Cosette, Pascal; Jouenne, Thierry; Hardouin, Julie

    2015-07-01

    Protein lysine acetylation is a reversible and highly regulated post-translational modification with the well demonstrated physiological relevance in eukaryotes. Recently, its important role in the regulation of metabolic processes in bacteria was highlighted. Here, we reported the lysine acetylproteome of Pseudomonas aeruginosa using a proteomic approach. We identified 430 unique peptides corresponding to 320 acetylated proteins. In addition to the proteins involved in various metabolic pathways, several enzymes contributing to the lipopolysaccharides biosynthesis were characterized as acetylated. This data set illustrated the abundance and the diversity of acetylated lysine proteins in P. aeruginosa and opens opportunities to explore the role of the acetylation in the bacterial physiology. PMID:25900529

  19. Dissemination of carbapenemase-producing Enterobacteriaceae and Pseudomonas aeruginosa in Romania.

    PubMed

    Dortet, Laurent; Flonta, Mirela; Boudehen, Yves-Marie; Creton, Elodie; Bernabeu, Sandrine; Vogel, Anaïs; Naas, Thierry

    2015-11-01

    Fifteen carbapenemase-producing Enterobacteriaceae isolates and 12 carbapenemase-producing Pseudomonas aeruginosa isolates were recovered from patients hospitalized between August 2011 and March 2013 at the Hospital of Infectious Disease, Cluj-Napoca, Romania. One KPC-, nine NDM-1-, four OXA-48-, and one VIM-4-producing Enterobacteriaceae isolates along with 11 VIM-2-producing and one IMP-13-producing P. aeruginosa isolates were recovered from clinical samples. All carbapenemase genes were located on self-conjugative plasmids and were associated with other resistance determinants, including extended-spectrum β-lactamases and RmtC methylases. PMID:26303798

  20. Cloning and expression of a gene segment encoding the enzymatic moiety of Pseudomonas aeruginosa exotoxin A.

    PubMed Central

    Mozola, M A; Wilson, R B; Jordan, E M; Draper, R K; Clowes, R C

    1984-01-01

    Using the broad-host-range plasmid vector pRO1614, we cloned a segment of the gene from Pseudomonas aeruginosa PA103 encoding the enzymatically active part of the exotoxin A protein. Expression of the cloned gene segment has been achieved both in Escherichia coli and in a nontoxigenic P. aeruginosa host, as assayed by the production of exotoxin A-related antigen and by the ability of the gene product to ADP-ribosylate elongation factor 2. Western blot hybridization analysis revealed a series of polypeptides antigenically related to exotoxin A, the largest of which had a molecular weight of ca. 50,000. Images PMID:6086583

  1. 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

  2. Genome-Wide Study of Pseudomonas aeruginosa Outer Membrane Protein Immunogenicity Using Self-Assembling Protein Microarrays▿ †

    PubMed Central

    Montor, Wagner R.; Huang, Jin; Hu, Yanhui; Hainsworth, Eugenie; Lynch, Susan; Kronish, Jeannine-Weiner; Ordonez, Claudia L.; Logvinenko, Tanya; Lory, Stephen; LaBaer, Joshua

    2009-01-01

    Pseudomonas aeruginosa is responsible for potentially life-threatening infections in individuals with compromised defense mechanisms and those with cystic fibrosis. P. aeruginosa infection is notable for the appearance of a humoral response to some known antigens, such as flagellin C, elastase, alkaline protease, and others. Although a number of immunogenic proteins are known, no effective vaccine has been approved yet. Here, we report a comprehensive study of all 262 outer membrane and exported P. aeruginosa PAO1 proteins by a modified protein microarray methodology called the nucleic acid-programmable protein array. From this study, it was possible to identify 12 proteins that trigger an adaptive immune response in cystic fibrosis and acutely infected patients, providing valuable information about which bacterial proteins are actually recognized by the immune system in vivo during the natural course of infection. The differential detections of these proteins in patients and controls proved to be statistically significant (P < 0.01). The study provides a list of potential candidates for the improvement of serological diagnostics and the development of vaccines. PMID:19737893

  3. 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

  4. 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

  5. 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

  6. Within-Host Evolution of Pseudomonas aeruginosa Reveals Adaptation toward Iron Acquisition from Hemoglobin

    PubMed Central

    Marvig, Rasmus Lykke; Damkiær, Søren; Khademi, S. M. Hossein; Markussen, Trine M.; Molin, Søren

    2014-01-01

    ABSTRACT Pseudomonas aeruginosa airway infections are a major cause of mortality and morbidity of cystic fibrosis (CF) patients. In order to persist, P. aeruginosa depends on acquiring iron from its host, and multiple different iron acquisition systems may be active during infection. This includes the pyoverdine siderophore and the Pseudomonas heme utilization (phu) system. While the regulation and mechanisms of several iron-scavenging systems are well described, it is not clear whether such systems are targets for selection during adaptation of P. aeruginosa to the host environment. Here we investigated the within-host evolution of the transmissible P. aeruginosa DK2 lineage. We found positive selection for promoter mutations leading to increased expression of the phu system. By mimicking conditions of the CF airways in vitro, we experimentally demonstrate that increased expression of phuR confers a growth advantage in the presence of hemoglobin, thus suggesting that P. aeruginosa evolves toward iron acquisition from hemoglobin. To rule out that this adaptive trait is specific to the DK2 lineage, we inspected the genomes of additional P. aeruginosa lineages isolated from CF airways and found similar adaptive evolution in two distinct lineages (DK1 and PA clone C). Furthermore, in all three lineages, phuR promoter mutations coincided with the loss of pyoverdine production, suggesting that within-host adaptation toward heme utilization is triggered by the loss of pyoverdine production. Targeting heme utilization might therefore be a promising strategy for the treatment of P. aeruginosa infections in CF patients. PMID:24803516

  7. 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. PMID:24595188

  8. 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

  9. 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

  10. Growth behavior prediction of fresh catfish fillet with Pseudomonas aeruginosa under stresses of allyl isothiocyanate, temperature and modified atmosphere

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas aeruginosa, a common spoilage microorganism in fish, grows rapidly when temperature rises above 4 degree C. The combination of allyl isothiocyanate (AIT) and modified atmosphere (MA) was applied and proved to be effective to retard the growth of P. aeruginosa. The objective of this resea...

  11. 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...

  12. Evaluation of Vitek2 and BD Phoenix in antimicrobial susceptibility testing of Acinetobacter baumannii and Pseudomonas aeruginosa.

    PubMed

    Jekarl, Dong Wook; Han, Sang Bong; Kim, Yoon Joo; Shin, Sang Hyun; Park, Kang Gyun; Park, Jung Jun; Han, Kyungja; Park, Yeon-Joon

    2010-08-01

    The accuracy of antimicrobial susceptibility testing of Vitek2 and BD Phoenix against Acinetobacter baumannii and Pseudomonas aeruginosa was evaluated. Both systems showed overall categoric agreement of < or =90% for cefepime and ceftazidime against A. baumannii and imipenem and cefepime (and ceftazidime with Vitek2) against P. aeruginosa because of high minor error rates. PMID:20638609

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

    PubMed Central

    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

  14. 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

  15. 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

  16. Synergistic interactions of Pseudomonas aeruginosa and Staphylococcus aureus in an in vitro wound model.

    PubMed

    DeLeon, Stephanie; Clinton, Allie; Fowler, Haley; Everett, Jake; Horswill, Alexander R; Rumbaugh, Kendra P

    2014-11-01

    In individuals with polymicrobial infections, microbes often display synergistic interactions that can enhance their colonization, virulence, or persistence. One of the most prevalent types of polymicrobial infection occurs in chronic wounds, where Pseudomonas aeruginosa and Staphylococcus aureus are the two most common causes. Although they are the most commonly associated microbial species in wound infections, very little is known about their interspecies relationship. Evidence suggests that P. aeruginosa-S. aureus coinfections are more virulent than monoculture infection with either species; however, difficulties in growing these two pathogens together in vitro have hampered attempts to uncover the mechanisms involved. Here we describe a simple and clinically relevant in vitro wound model that supported concomitant growth of P. aeruginosa and S. aureus. We observed that the ability of P. aeruginosa and S. aureus to survive antibiotic treatment increased when they were grown together in planktonic cocultures and that antibiotic tolerance was further enhanced when they were grown together in the wound model. We attributed this enhanced tolerance to both the "host-derived" and "bacterium-derived" matrix components. Taken together, our data indicate that P. aeruginosa and S. aureus may benefit each other by coinfecting wounds and that the host-derived matrix may serve as important a role as the bacterium-derived matrix in protecting bacteria from some antibiotics. PMID:25156721

  17. Whole, submandibular, and parotid saliva-mediated aggregation of Pseudomonas aeruginosa in cystic fibrosis.

    PubMed Central

    Komiyama, K; Habbick, B F; Tumber, S K

    1989-01-01

    The aggregation of mucoid and nonmucoid Pseudomonas aeruginosa by submandibular, parotid, and whole saliva from patients with cystic fibrosis (CF) and non-CF subjects was investigated. There were significant differences (P less than 0.01) in aggregation of mucoid and nonmucoid variants of P. aeruginosa by submandibular and whole saliva from CF patients and non-CF subjects. However, the differences in the parotid secretion were not as pronounced. Patients with CF who were colonized with P. aeruginosa demonstrated a significantly higher (P less than 0.05) percent aggregation of the mucoid variants by the submandibular secretion and of both mucoid and nonmucoid variants by whole saliva, compared with corresponding secretions from patients with CF not colonized with this pathogen. The parotid saliva aggregation activity was not markedly different for the two groups with CF. From patients with CF, whole saliva demonstrated a higher percent P. aeruginosa aggregation than did the submandibular saliva. In non-CF subjects, however, the percent aggregation of P. aeruginosa by submandibular saliva was higher than that by whole saliva. Our results indicate that the sero-mucous products of the submandibular gland have a more significant role in P. aeruginosa aggregation than the serous secreting parotid cells and that the submandibular secretion is possibly responsible for the differences in oral colonization by this pathogen in subjects with and without CF. PMID:2494114

  18. 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. PMID:20562125

  19. 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

  20. Potential effects of erythromycin on host defense systems and virulence of Pseudomonas aeruginosa.

    PubMed Central

    Hirakata, Y; Kaku, M; Mizukane, R; Ishida, K; Furuya, N; Matsumoto, T; Tateda, K; Yamaguchi, K

    1992-01-01

    We evaluated several potential effects of erythromycin (EM) on host defense systems and the virulence of Pseudomonas aeruginosa. Peritoneal macrophages obtained from mice given 250 mg of EM per kg of body weight for 7 days by the intraperitoneal, intravenous, subcutaneous, or oral route produced significantly greater amounts of thymocyte-activating factors. These data suggest that EM enhances the in vivo production of cytokines, such as interleukins 1 and 6. Treatment of P. aeruginosa D4 with subinhibitory concentrations of EM enhanced the association of bacteria with murine Kupffer cells in vitro and increased bacterial clearance from the blood in mice. EM suppressed the in vitro production of exotoxin A, total protease, elastase, and phospholipase C by P. aeruginosa D4; exotoxin A production by P. aeruginosa PA-103; and total protease production by P. aeruginosa B16 and PAO1 in a generally dose-dependent manner. These data demonstrate that EM produces various effects in addition to its direct antimicrobial activity, suggesting that it has potential as an immunomodulator or bacterial virulence-suppressing agent against P. aeruginosa and other infections. PMID:1416882

  1. Analysis of the periplasmic proteome of Pseudomonas aeruginosa, a metabolically versatile opportunistic pathogen.

    PubMed

    Imperi, Francesco; Ciccosanti, Fabiola; Perdomo, Ariel Basulto; Tiburzi, Federica; Mancone, Carmine; Alonzi, Tonino; Ascenzi, Paolo; Piacentini, Mauro; Visca, Paolo; Fimia, Gian Maria

    2009-04-01

    The Gram-negative bacterium Pseudomonas aeruginosa is a main cause of infection in hospitalized, burned, immunocompromised, and cystic fibrosis patients. Many processes essential for P. aeruginosa pathogenesis, e.g., nutrient uptake, antibiotic resistance, and virulence, take place in the cell envelope and depend on components residing in the periplasmic space. Recent high-throughput studies focused on P. aeruginosa membrane compartments. However, the composition and dynamics of its periplasm remain largely uncharacterized. Here, we report a detailed description of the periplasmic proteome of the wild-type P. aeruginosa strain PAO1 by 2-DE and MALDI-TOF/TOF analysis. Three extraction methods were compared at proteome level in order to achieve the most reliable and comprehensive periplasmic protein map. A total of 495 spots representing 395 different proteins were identified. Most of the high intensity spots corresponded to periplasmic proteins, while cytoplasmic contaminants were mainly detected among faint spots. The majority of the identified periplasmic proteins is involved in transport, cell-envelope integrity, and protein folding control. Notably, more than 30% still has an unpredicted function. This work provides the first overview of the P. aeruginosa periplasm and offers the basis for future studies on periplasmic proteome changes occurring during P. aeruginosa adaptation to different environments and/or antibiotic treatments. PMID:19333994

  2. 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

  3. 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

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

    PubMed

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

    2015-08-01

    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

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

    PubMed

    Yang, Liang; Liu, Yang; Markussen, Trine; Høiby, Niels; Tolker-Nielsen, Tim; Molin, Søren

    2011-08-01

    Biofilm infections may not simply be the result of colonization by one bacterium, but rather the consequence of pathogenic contributions from several bacteria. Interspecies interactions of different organisms in mixed-species biofilms remain largely unexplained, but knowledge of these is very important for understanding of biofilm physiology and the treatment of biofilm-related infectious diseases. Here, we have investigated interactions of two of the major bacterial species of cystic fibrosis lung microbial communities -Pseudomonas aeruginosa and Staphylococcus aureus- when grown in co-culture biofilms. By growing co-culture biofilms of S. aureus with P. aeruginosa mutants in a flow-chamber system and observing them using confocal laser scanning microscopy, we show that wild-type P. aeruginosa PAO1 facilitates S. aureus microcolony formation. In contrast, P. aeruginosa mucA and rpoN mutants do not facilitate S. aureus microcolony formation and tend to outcompete S. aureus in co-culture biofilms. Further investigations reveal that extracellular DNA (eDNA) plays an important role in S. aureus microcolony formation and that P. aeruginosa type IV pili are required for this process, probably through their ability to bind to eDNA. Furthermore, P. aeruginosa is able to protect S. aureus against Dictyostelium discoideum phagocytosis in co-culture biofilms. PMID:21595754

  6. 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

  7. 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

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

    PubMed

    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

  9. Activity of Chitosans in combination with antibiotics in Pseudomonas aeruginosa

    PubMed Central

    Tin, San; Sakharkar, Kishore R.; Lim, Chu Sing; Sakharkar, Meena K.

    2009-01-01

    Chitosan and its derivative water soluble Chitosan oligosaccharide are used in a variety of applications in pharmaceutical preparations. In this study, 2 wild (ATCC 15729 and PAO1) and 2 mutant strains (PT121 and PT149) of P. aeruginosa are investigated for drug-drug interactions in vitro. 10 antimicrobial agents (antibiotics) are combined with different degree of deacetylated Chitosans and Chitosan oligosaccharide. All the chitosans show synergistic activity with sulfamethoxazole, a sulfonamide antimicrobial agent. It is interesting to observe that the MIC value for the MexEF-OprN overexpressing mutant strain of P. aeruginosa is 5 fold higher than the other strains under investigation suggesting a possible role of this efflux pump in Sulfamethoxazole efflux. The findings suggest on the use of chitosans as enhancing agent in combination with antibiotics in pharmaceutical preparations. PMID:19173037

  10. 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

  11. 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

  12. 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

  13. 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

  14. Outbreak of infections caused by Pseudomonas aeruginosa producing VIM-1 carbapenemase in Greece.

    PubMed

    Tsakris, A; Pournaras, S; Woodford, N; Palepou, M F; Babini, G S; Douboyas, J; Livermore, D M

    2000-03-01

    Resistance to imipenem and meropenem was observed in 211 (16.5%) isolates of Pseudomonas aeruginosa recovered in a Greek university hospital during 1996 to 1998. In six isolates selected from throughout this period, high-level resistance to both carbapenems (MICs >/= 128 microg/ml) was associated with production of the class B beta-lactamase VIM-1. bla(VIM)-bearing isolates belonged to serotype O:12 and were indistinguishable by pulsed-field gel electrophoresis. PMID:10699045

  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. Draft Genome Sequence of a Clinically Isolated Extensively Drug-Resistant Pseudomonas aeruginosa Strain

    PubMed Central

    Manivannan, Bhavani; Mahalingam, Niranjana; Jadhao, Sudhir; Mishra, Amrita; Nilawe, Pravin

    2016-01-01

    We present the draft genome assembly of an extensively drug-resistant (XDR) Pseudomonas aeruginosa strain isolated from a patient with a history of genito urinary tuberculosis. The draft genome is 7,022,546 bp with a G+C content of 65.48%. It carries 7 phage genomes, genes for quorum sensing, biofilm formation, virulence, and antibiotic resistance. PMID:27013045

  17. Recombinant expression, refolding, purification and characterization of Pseudomonas aeruginosa protease IV in Escherichia coli.

    PubMed

    Zhao, Mingzhi; Cai, Man; Wu, Feilin; Zhang, Yao; Xiong, Zhi; Xu, Ping

    2016-10-01

    Several protease IV enzymes are widely used in proteomic research. Specifically, protease IV from Pseudomonas aeruginosa has lysyl endopeptidase activity. Here, we report the recombinant expression, refolding, activation, and purification of this protease in Escherichia coli. Proteolytic instability of the activated intermediate, a major obstacle for efficient production, is controlled through ammonium sulfate precipitation. The purified protease IV exhibits superior lysyl endopeptidase activity compared to a commercial product. PMID:27260967

  18. Typing of Pseudomonas aeruginosa: comparison of the phage procedure with the pyocine technique

    PubMed Central

    Bernstein-Ziv, Ruth; Mushin, Rose; Rabinowitz, Kurt

    1973-01-01

    Two hundred and sixty strains of Pseudomonas aeruginosa were isolated from patients of the Asaf Harofe Government Hospital. The strains were typed by phage technique and 64 of them were also typed according to pyocine sensitivity. The two methods proved complementary, and reduced the number of untypable strains. Phage typing was performed with both routine test dilution (RTD) and more concentrated phage suspensions. The most reliable results were obtained at 100 RTD. PMID:4198203

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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. PMID:17975212

  4. 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

  5. Pseudomonas aeruginosa: arsenal of resistance mechanisms, decades of changing resistance profiles, and future antimicrobial therapies.

    PubMed

    El Zowalaty, Mohamed E; Al Thani, Asmaa A; Webster, Thomas J; El Zowalaty, Ahmed E; Schweizer, Herbert P; Nasrallah, Gheyath K; Marei, Hany E; Ashour, Hossam M

    2015-01-01

    Antimicrobial resistance is one of the most serious public health issues facing humans since the discovery of antimicrobial agents. The frequent, prolonged, and uncontrolled use of antimicrobial agents are major factors in the emergence of antimicrobial-resistant bacterial strains, including multidrug-resistant variants. Pseudomonas aeruginosa is a leading cause of nosocomial infections. The abundant data on the increased resistance to antipseudomonal agents support the need for global action. There is a paucity of new classes of antibiotics active against P. aeruginosa. Here, we discuss recent antibacterial resistance profiles and mechanisms of resistance by P. aeruginosa. We also review future potential methods for controlling antibiotic-resistant bacteria, such as phage therapy, nanotechnology and antipseudomonal vaccines. PMID:26439366

  6. 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

  7. 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

  8. 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

  9. Treatment of Pseudomonas aeruginosa-infected orthopedic prostheses with ceftazidime-ciprofloxacin antibiotic combination.

    PubMed

    Brouqui, P; Rousseau, M C; Stein, A; Drancourt, M; Raoult, D

    1995-11-01

    Indwelling device infections are associated with considerable morbidity and extremely high cost. Pseudomonas aeruginosa is the most frequent gram-negative etiologic agent associated with infections of indwelling catheters and foreign body implants. It is generally agreed that eradication of infection in the presence of a foreign body requires removal of the foreign body. Using a combination of ceftazidime and ciprofloxacin, we cured nine of nine patients with P. aeruginosa-infected osteosynthetic material and four of five patients with hip and knee prostheses without removing the foreign material. Follow-up was for a mean of 21 months (range, 6 to 60 months). Some patients experienced minor side effects (arthralgia in one patient and rash in another patient). We conclude that this combination is effective and safe and should be useful in the treatment of P. aeruginosa-infected orthopedic implants. PMID:8585720

  10. 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.

  11. 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

  12. 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.

  13. Pseudomonas aeruginosa adaptation in the nasopharyngeal reservoir leads to migration and persistence in the lungs.

    PubMed

    Fothergill, Joanne L; Neill, Daniel R; Loman, Nick; Winstanley, Craig; Kadioglu, Aras

    2014-01-01

    Chronic bacterial infections are a key feature of a variety of lung conditions. The opportunistic bacterium, Pseudomonas aeruginosa, is extremely skilled at both colonizing and persisting in the airways of patients with lung damage. It has been suggested that the upper airways (including the paranasal sinuses and nasopharynx) play an important role as a silent reservoir of bacteria. Over time, P. aeruginosa can adapt to its niche, leading to increased resistance in the face of the immune system and intense therapy regimes. Here we describe a mouse inhalation model of P. aeruginosa chronic infection that can be studied for at least 28 days. We present evidence for adaptation in vivo, in terms of genotype and phenotype including antibiotic resistance. Our data suggest that there is persistence in the upper respiratory tract and that this is key in the establishment of lung infection. This model provides a unique platform for studying evolutionary dynamics and therapeutics. PMID:25179232

  14. Purification of outer membrane vesicles from Pseudomonas aeruginosa and their activation of an IL-8 response

    PubMed Central

    Bauman, Susanne J.; Kuehn, Meta J.

    2012-01-01

    Considerable lung injury results from the inflammatory response to Pseudomonas aeruginosa infections in patients with cystic fibrosis (CF). The P. aeruginosa laboratory strain PAO1, an environmental isolate, and isolates from CF patients were cultured in vitro and outer membrane vesicles from those cultures were quantitated, purified, and characterized. Vesicles were produced throughout the growth phases of the culture and vesicle yield was strain-independent. Strain-dependent differences in the protein composition of vesicles were quantitated and identified. The aminopeptidase PaAP (PA2939) was highly enriched in vesicles from CF isolates. Vesicles from all strains elicited IL-8 secretion by lung epithelial cells. These results suggest that P. aeruginosa colonizing the CF lung may produce vesicles with a particular composition and that the vesicles could contribute to inflammation. PMID:16807039

  15. 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

  16. 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

  17. 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

  18. Chemical Genetics Reveals Environment-Specific Roles for Quorum Sensing Circuits in Pseudomonas aeruginosa.

    PubMed

    Welsh, Michael A; Blackwell, Helen E

    2016-03-17

    Nutritional cues differentially influence the activities of the three quorum sensing (QS) circuits-Las, Rhl, and Pqs-in the pathogen Pseudomonas aeruginosa. A full understanding of how these systems work together to tune virulence factor production to the environment is lacking. Here, we used chemical probes to evaluate the contribution of each QS circuit to virulence in wild-type P. aeruginosa under defined environmental conditions. Our results indicate that Rhl and Pqs drive virulence factor production in phosphate- and iron-limiting environments, while Las has a minor influence. Consequently, simultaneous inhibition of Rhl and Pqs can attenuate virulence in environments where Las inhibition fails. The activity trends generated in this study can be extrapolated to predict QS inhibitor activity in infection-relevant environments, such as cystic fibrosis sputum. These results indicate that environmental signals can drastically alter the efficacy of small-molecule QS inhibitors in P. aeruginosa and possibly other pathogens. PMID:26905657

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

    PubMed Central

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

    2015-01-01

    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

  20. Engineering PQS Biosynthesis Pathway for Enhancement of Bioelectricity Production in Pseudomonas aeruginosa Microbial Fuel Cells

    PubMed Central

    Cao, Bin; Seviour, Thomas; Nesatyy, Victor J.; Marsili, Enrico; Kjelleberg, Staffan; Givskov, Michael; Tolker-Nielsen, Tim; Song, Hao; Loo, Joachim Say Chye; Yang, Liang

    2013-01-01

    The biosynthesis of the redox shuttle, phenazines, in Pseudomonas aeruginosa, an ubiquitous microorganism in wastewater microflora, is regulated by the 2-heptyl-3,4-dihydroxyquinoline (PQS) quorum-sensing system. However, PQS inhibits anaerobic growth of P. aeruginosa. We constructed a P. aeruginosa strain that produces higher concentrations of phenazines under anaerobic conditions by over-expressing the PqsE effector in a PQS negative ΔpqsC mutant. The engineered strain exhibited an improved electrical performance in microbial fuel cells (MFCs) and potentiostat-controlled electrochemical cells with an approximate five-fold increase of maximum current density relative to the parent strain. Electrochemical analysis showed that the current increase correlates with an over-synthesis of phenazines. These results therefore demonstrate that targeting microbial cell-to-cell communication by genetic engineering is a suitable technique to improve power output of bioelectrochemical systems. PMID:23700414

  1. Pseudomonas aeruginosa Evolutionary Adaptation and Diversification in Cystic Fibrosis Chronic Lung Infections.

    PubMed

    Winstanley, Craig; O'Brien, Siobhan; Brockhurst, Michael A

    2016-05-01

    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. The innate immune protein calprotectin promotes Pseudomonas aeruginosa and Staphylococcus aureus interaction.

    PubMed

    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

  3. 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

  4. 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

  5. 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

  6. 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

  7. A Long-Chain Flavodoxin Protects Pseudomonas aeruginosa from Oxidative Stress and Host Bacterial Clearance

    PubMed Central

    Moyano, Alejandro J.; Krapp, Adriana R.; Mondotte, Juan A.; Bocco, José L.; Saleh, Maria-Carla; Carrillo, Néstor; Smania, Andrea M.

    2014-01-01

    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 flavodoxin 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

  8. 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. PMID:24790091

  9. Multilocus Sequence Typing and Phylogenetic Analyses of Pseudomonas aeruginosa Isolates from the Ocean▿

    PubMed Central

    Khan, Nurul Huda; Ahsan, Mahbuba; Yoshizawa, Susumu; Hosoya, Shoichi; Yokota, Akira; Kogure, Kazuhiro

    2008-01-01

    Recent isolation of Pseudomonas aeruginosa strains from the open ocean and subsequent pulsed-field gel electrophoresis analyses indicate that these strains have a unique genotype (N. H. Khan, Y. Ishii, N. Kimata-Kino, H. Esaki, T. Nishino, M. Nishimura, and K. Kogure, Microb. Ecol. 53:173-186, 2007). We hypothesized that ocean P. aeruginosa strains have a unique phylogenetic position relative to other strains. The objective of this study was to clarify the intraspecies phylogenetic relationship between marine strains and other strains from various geographical locations. Considering the advantages of using databases, multilocus sequence typing (MLST) was chosen for the typing and discrimination of ocean P. aeruginosa strains. Seven housekeeping genes (acsA, aroE, guaA, mutL, nuoD, ppsA, and trpE) were analyzed, and the results were compared with data on the MLST website. These genes were also used for phylogenetic analysis of P. aeruginosa. Rooted and unrooted phylogenetic trees were generated for each gene locus and the concatenated gene fragments. MLST data showed that all the ocean strains were new. Trees constructed for individual and concatenated genes revealed that ocean P. aeruginosa strains have clusters distinct from those of other P. aeruginosa strains. These clusters roughly reflected the geographical locations of the isolates. These data support our previous findings that P. aeruginosa strains are present in the ocean. It can be concluded that the ocean P. aeruginosa strains have diverged from other isolates and form a distinct cluster based on MLST and phylogenetic analyses of seven housekeeping genes. PMID:18757570

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

    PubMed Central

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

    2012-01-01

    Staphylococcus aureus and Pseudomonas aeruginosa are common nosocomial pathogens responsible for biofilm-associated infections. Proton pump inhibitors (PPI), such as esomeprazole, may have novel antimicrobial properties. The objective of this study was to assess whether esomeprazole prevents sessile bacterial growth and biofilm formation and whether it may have synergistic killing effects with standard antibiotics. The antibiofilm activity of esomeprazole at 0.25 mM was tested against two strains each of S. aureus and P. aeruginosa. Bacterial biofilms were prepared using a commercially available 96-peg-plate Calgary biofilm device. Sessile bacterial CFU counts and biomass were assessed during 72 hours of esomeprazole exposure. The killing activities after an additional 24 hours of vancomycin (against S. aureus) and meropenem (against P. aeruginosa) treatment with or without preexposure to esomeprazole were also assessed by CFU and biomass analyses. P. aeruginosa and S. aureus strains exposed to esomeprazole displayed decreased sessile bacterial growth and biomass (P < 0.001, each parameter). After 72 h of exposure, there was a 1-log10 decrease in the CFU/ml of esomeprazole-exposed P. aeruginosa and S. aureus strains compared to controls (P < 0.001). After 72 h of exposure, measured absorbance was 100% greater in P. aeruginosa control strains than in esomeprazole-exposed strains (P < 0.001). Increased killing and decreased biomass were observed for esomeprazole-treated bacteria compared to untreated controls exposed to conventional antibiotics (P < 0.001, each parameter). Reduced biofilm growth after 24 h was visibly apparent by light micrographs for P. aeruginosa and S. aureus isolates exposed to esomeprazole compared to untreated controls. In conclusion, esomeprazole demonstrated an antibiofilm effect against biofilm-producing S. aureus and P. aeruginosa. PMID:22664967

  11. Affecting Pseudomonas aeruginosa Phenotypic Plasticity by Quorum Sensing Dysregulation Hampers Pathogenicity in Murine Chronic Lung Infection

    PubMed Central

    Bondí, Roslen; Messina, Marco; De Fino, Ida; Bragonzi, Alessandra; Rampioni, Giordano; Leoni, Livia

    2014-01-01

    In Pseudomonas aeruginosa quorum sensing (QS) activates the production of virulence factors, playing a critical role in pathogenesis. Multiple negative regulators modulate the timing and the extent of the QS response either in the pre-quorum or post-quorum phases of growth. This regulation likely increases P. aeruginosa phenotypic plasticity and population fitness, facilitating colonization of challenging environments such as higher organisms. Accordingly, in addition to the factors required for QS signals synthesis and response, also QS regulators have been proposed as targets for anti-virulence therapies. However, while it is known that P. aeruginosa mutants impaired in QS are attenuated in their pathogenic potential, the effect of mutations causing a dysregulated timing and/or magnitude of the QS response has been poorly investigated so far in animal models of infection. In order to investigate the impact of QS dysregulation on P. aeruginosa pathogenesis in a murine model of lung infection, the QteE and RsaL proteins have been selected as representatives of negative regulators controlling P. aeruginosa QS in the pre- and post-quorum periods, respectively. Results showed that the qteE mutation does not affect P. aeruginosa lethality and ability to establish chronic infection in mice, despite causing a premature QS response and enhanced virulence factors production in test tube cultures compared to the wild type. Conversely, the post-quorum dysregulation caused by the rsaL mutation hampers the establishment of P. aeruginosa chronic lung infection in mice without affecting the mortality rate. On the whole, this study contributes to a better understanding of the impact of QS regulation on P. aeruginosa phenotypic plasticity during the infection process. Possible fallouts of these findings in the anti-virulence therapy field are also discussed. PMID:25420086

  12. Nitrosoglutathione generating nitric oxide nanoparticles as an improved strategy for combating Pseudomonas aeruginosa-infected wounds.

    PubMed

    Chouake, Jason; Schairer, David; Kutner, Allison; Sanchez, David A; Makdisi, Joy; Blecher-Paz, Karin; Nacharaju, Parimala; Tuckman-Vernon, Chaim; Gialanella, Phil; Friedman, Joel M; Nosanchuk, Joshua D; Friedman, Adam J

    2012-12-01

    Pseudomonas aeruginosa is a community-acquired, nosocomial pathogen that is an important cause of human morbidity and mortality; it is intrinsically resistant to several antibiotics and is capable of developing resistance to newly developed drugs via a variety of mechanisms. P aeruginosa's ubiquity and multidrug resistance (MDR) warrants the development of innovative methods that overcome its ability to develop resistance. We have previously described a nitric oxide-releasing nanoparticle (NO-np) platform that effectively kills gram-positive and gram-negative organisms in vitro and accelerates clinical recovery in vivo in murine wound and abscess infection models. We have also demonstrated that when glutathione (GSH) is added to NO-np, the nitroso intermediate S-nitrosoglutathione (GSNO) is formed, which has greater activity against P aeruginosa and other gram-negative organisms compared with NO-np alone. In the current study, we evaluate the potential of NO-np to generate GSNO both in vitro and in vivo in a murine excisional wound model infected with an MDR clinical isolate of P aeruginosa. Whereas NO-np alone inhibited P aeruginosa growth in vitro for up to 8 hours, NO-np+GSH completely inhibited P aeruginosa growth for 24 hours. Percent survival in the NO-np+GSH-treated isolates was significantly lower than in the NO-np (36.1% vs 8.3%; P=.004). In addition, NO-np+GSH accelerated wound closure in P aeruginosa-infected wounds, and NO-np+GSH-treated wounds had significantly lower bacterial burden when compared to NO-np-treated wounds (P<.001). We conclude that GSNO is easily generated from our NO-np platform and has the potential to be used as an antimicrobial agent against MDR organisms such as P aeruginosa. PMID:23377518

  13. 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

  14. 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

  15. Importance of Tryptophan in Transforming an Amphipathic Peptide into a Pseudomonas aeruginosa-Targeted Antimicrobial Peptide

    PubMed Central

    Zhu, Xin; Ma, Zhi; Wang, Jiajun; Chou, Shuli; Shan, Anshan

    2014-01-01

    Here, we found that simple substitution of amino acids in the middle position of the hydrophobic face of an amphipathic peptide RI16 with tryptophan (T9W) considerably transformed into an antimicrobial peptide specifically targeting Pseudomonas aeruginosa. Minimal inhibitory concentration (MIC) results demonstrated that T9W had a strong and specifically antimicrobial activity against P. aeruginosa, including antibiotic-resistant strains, but was not active against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Staphyfococcus epidermidis. Fluorescent spectroscopic assays indicated that T9W interacted with the membrane of P. aeruginosa, depolarizing the outer and the inner membrane of bacterial cells. Salt susceptibility assay showed that T9W still maintained its strong anti-pseudomonas activity in the presence of salts at physiological concentrations, and in hemolytic and MTT assays T9W also showed no toxicity against human blood cells and macrophages. In vivo assay demonstrated that T9W also displayed no toxicity to Chinese Kun Ming (KM) mice. Furthermore, the strong antibiofilm activity was also observed with the peptide T9W, which decreased the percentage of biomass formation in a dose-dependent manner. Overall, these findings indicated that design of single-pathogen antimicrobial agents can be achieved by simple amino acid mutation in naturally occurring peptide sequences and this study suggested a model of optimization/design of anti-pseudomonas drugs in which the tryptophan residue was a conserved element. PMID:25494332

  16. 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

  17. 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. PMID:26042975

  18. Genome-wide Screen of Pseudomonas aeruginosa in Saccharomyces cerevisiae Identifies New Virulence Factors

    PubMed Central

    Zrieq, Rafat; Sana, Thibault G.; Vergin, Sandra; Garvis, Steve; Volfson, Irina; Bleves, Sophie; Voulhoux, Romé; Hegemann, Johannes H.

    2015-01-01

    Pseudomonas aeruginosa is a human opportunistic pathogen that causes mortality in cystic fibrosis and immunocompromised patients. While many virulence factors of this pathogen have already been identified, several remain to be discovered. In this respect we set an unprecedented genome-wide screen of a P. aeruginosa expression library based on a yeast growth phenotype. Fifty-one candidates were selected in athree-round screening process. The robustness of the screen was validated by the selection of three well known secreted proteins including one demonstrated virulence factor, the protease LepA. Further in silico sorting of the 51 candidates highlighted three potential new Pseudomonas effector candidates (Pec). By testing the cytotoxicity of wild type P. aeruginosa vs. pec mutants toward macrophages and the virulence in the Caenorhabditis elegans model, we demonstrated that the three selected Pecs are novel virulence factors of P. aeruginosa. Additional cellular localization experiments in the host revealed specific localization for Pec1 and Pec2 that could inform about their respective functions. PMID:26636043

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. In Vitro Analysis of Pseudomonas aeruginosa Virulence Using Conditions That Mimic the Environment at Specific Infection Sites.

    PubMed

    Colmer-Hamood, J A; Dzvova, N; Kruczek, C; Hamood, A N

    2016-01-01

    Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes chronic lung infection in patients with cystic fibrosis (CF) and acute systemic infections in severely burned patients and immunocompromised patients including cancer patients undergoing chemotherapy and HIV infected individuals. In response to the environmental conditions at specific infection sites, P. aeruginosa expresses certain sets of cell-associated and extracellular virulence factors that produce tissue damage. Analyzing the mechanisms that govern the production of these virulence factors in vitro requires media that closely mimic the environmental conditions within the infection sites. In this chapter, we review studies based on media that closely resemble three in vivo conditions, the thick mucus accumulated within the lung alveoli of CF patients, the serum-rich wound bed and the bloodstream. Media resembling the CF alveolar mucus include standard laboratory media supplemented with sputum obtained from CF patients as well as prepared synthetic mucus media formulated to contain the individual components of CF sputum. Media supplemented with serum or individual serum components have served as surrogates for the soluble host components of wound infections, while whole blood has been used to investigate the adaptation of pathogens to the bloodstream. Studies using these media have provided valuable information regarding P. aeruginosa gene expression in different host environments as varying sets of genes were di