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Sample records for aeruginosa clinical strains

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

    PubMed

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

    2014-01-01

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

  2. Screening of Molecular Virulence Markers in Staphylococcus aureus and Pseudomonas aeruginosa Strains Isolated from Clinical Infections

    PubMed Central

    Cotar, Ani-Ioana; Chifiriuc, Mariana-Carmen; Dinu, Sorin; Bucur, Marcela; Iordache, Carmen; Banu, Otilia; Dracea, Olguta; Larion, Cristina; Lazar, Veronica

    2010-01-01

    Staphylococcus (S.) aureus and Pseudomonas (Ps.) aeruginosa are two of the most frequently opportunistic pathogens isolated in nosocomial infections, responsible for severe infections in immunocompromised hosts. The frequent emergence of antibiotic-resistant S. aureus and Ps. aeruginosa strains has determined the development of new strategies in order to elucidate the different mechanisms used by these bacteria at different stages of the infectious process, providing the scientists with new procedures for preventing, or at least improving, the control of S. aureus and Ps. aeruginosa infections. The purpose of this study was to characterize the molecular markers of virulence in S. aureus and Ps. aeruginosa strains isolated from different clinical specimens. We used multiplex and uniplex PCR assays to detect the genes encoding different cell-wall associated and extracellular virulence factors, in order to evaluate potential associations between the presence of putative virulence genes and the outcome of infections caused by these bacteria. Our results demonstrate that all the studied S. aureus and Ps. aeruginosa strains synthesize the majority of the investigated virulence determinants, probably responsible for different types of infections. PMID:21614207

  3. Anticandidal activity of medicinal plants and Pseudomonas aeruginosa strains of clinical specimens.

    PubMed

    Bora, Limpon

    2016-04-01

    This study was designed to investigate the in vitro anticandidal activity of some medicinal plants and Pseudomonas aeruginosa strains against Candida species. The antifungal activity of methanolic extracts of five medicinal plants, namely, Cinnamomum porrectum, Lippia nudiflora, Cestrum nocturnum, Trachyspermum ammi, and Sida carpinifolia were studied. The medicinal characteristics of these plants were compared with commercially used antibiotics. The antimicrobial assay was done by agar well diffusion and the broth dilution method. Among the plants used, T. ammi and C. nocturnum were found to be more potent than the others. Twenty P. aeruginosa strains were isolated from various clinical specimens. The total inhibitions obtained were found to be 47%, 38%, and 36% in blood agar, whereas in Sabouraud dextrose agar (SDA) the inhibitions were 57%, 48%, and 37%, respectively.

  4. Biofilm formation, antibiotic susceptibility and RAPD genotypes in Pseudomonas aeruginosa clinical strains isolated from single centre intensive care unit patients.

    PubMed

    Vaněrková, Martina; Mališová, Barbora; Kotásková, Iva; Holá, Veronika; Růžička, Filip; Freiberger, Tomáš

    2017-04-01

    The aim of this study was to analyse genotypes, antimicrobial susceptibility patterns and serotypes in Pseudomonas aeruginosa clinical strains, including the clonal dissemination of particular strains throughout various intensive care units in one medical centre. Using random amplified polymorphic DNA (RAPD-PCR) and P. aeruginosa antisera, 22 different genotypes and 8 serotypes were defined among 103 isolates from 48 patients. No direct association between P. aeruginosa strain genotypes and serotypes was observed. RAPD typing in strains with the same serotype revealed different genotypes and, on the contrary, most strains with a different serotype displayed the same amplification pattern. The resulting banding patterns showed a high degree of genetic heterogeneity among all isolates from the patients examined, suggesting a non-clonal relationship between isolates from these patients. A higher degree of antibiotic resistance and stronger biofilm production in common genotypes compared to rare ones and genetic homogeneity of the most resistant strains indicated the role of antibiotic pressure in acquiring resistant and more virulent strains in our hospital. In conclusion, genetic characterisation of P. aeruginosa strains using RAPD method was shown to be more accurate in epidemiological analyses than phenotyping.

  5. Antagonistic interactions peak at intermediate genetic distance in clinical and laboratory strains of Pseudomonas aeruginosa

    PubMed Central

    2012-01-01

    Background Bacteria excrete costly toxins to defend their ecological niche. The evolution of such antagonistic interactions between individuals is expected to depend on both the social environment and the strength of resource competition. Antagonism is expected to be weak among highly similar genotypes because most individuals are immune to antagonistic agents and among dissimilar genotypes because these are unlikely to be competing for the same resources and antagonism should not yield much benefit. The strength of antagonism is therefore expected to peak at intermediate genetic distance. Results We studied the ability of laboratory strains of Pseudomonas aeruginosa to prevent growth of 55 different clinical P. aeruginosa isolates derived from cystic fibrosis patients. Genetic distance was determined using genetic fingerprints. We found that the strength of antagonism was maximal among genotypes of intermediate genetic distance and we show that genetic distance and resource use are linked. Conclusions Our results suggest that the importance of social interactions like antagonism may be modulated by the strength of resource competition. PMID:22439760

  6. Restriction endonuclease analysis of clinical Pseudomonas aeruginosa strains: useful epidemiologic data from a simple and rapid method.

    PubMed Central

    Maher, W E; Kobe, M; Fass, R J

    1993-01-01

    Newer genetic techniques have replaced phenotypic methods of subtyping Pseudomonas aeruginosa strains. Widespread application of newer methodologies, however, may be limited by technologic complexity and the cost of equipment. We conducted restriction endonuclease analysis (REA) of sheared genomic DNAs from 48 clinical P. aeruginosa strains using the enzyme SalI and electrophoresis in horizontal, low-concentration (0.3 to 0.6%) agarose gels. Each REA profile consisted of a smear of lower-molecular-mass bands as well as a countable number of well-resolved bands in the 8.3- to 48.5-kbp range which could easily be compared when isolates were run side-by-side on the same gel. In general, the REA patterns of strains recovered from different patients differed by at least seven bands, and those of serial isolates from individual patients were identical or differed by, at most, two bands over this 8.3- to 48.5-kbp range. REA of strains already subtyped by field inversion gel electrophoresis revealed that the two techniques generally paralleled each other. Overall, some unrelated strains had similar REA profiles, but the relative simplicity and low cost of the approach coupled with the ability to demonstrate differences between most unrelated strains should make this type of REA an attractive first step in the investigation of institutional P. aeruginosa problems. Images PMID:8391021

  7. Detection of Quorum Sensing Activity in the Multidrug-Resistant Clinical Isolate Pseudomonas aeruginosa Strain GB11

    PubMed Central

    Cheng, Huey Jia; Ee, Robson; Cheong, Yuet Meng; Tan, Wen-Si; Yin, Wai-Fong; Chan, Kok-Gan

    2014-01-01

    A multidrug-resistant clinical bacteria strain GB11 was isolated from a wound swab on the leg of a patient. Identity of stain GB11 as Pseudomonas aeruginosa was validated by using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Detection of the production of signaling molecules, N-acylhomoserine lactones (AHLs), was conducted using three different bacterial biosensors. A total of four different AHLs were found to be produced by strain GB11, namely N-butyryl homoserine lactone (C4-HSL), N-hexanoylhomoserine lactone (C6-HSL), N-octanoyl homoserine lactone (C8-HSL) and N-3-oxo-dodecanoylhomoserine lactone (3-oxo-C12-HSL) using high resolution liquid chromatography tandem mass spectrometry (LC-MS/MS). Of these detected AHLs, 3-oxo-C12-HSL was found to be the most abundant AHL produced by P. aeruginosa GB11. PMID:25019635

  8. Silver Nanoparticles: Biosynthesis Using an ATCC Reference Strain of Pseudomonas aeruginosa and Activity as Broad Spectrum Clinical Antibacterial Agents

    PubMed Central

    Quinteros, Melisa A.; Aiassa Martínez, Ivana M.; Dalmasso, Pablo R.; Páez, Paulina L.

    2016-01-01

    Currently, the biosynthesis of silver-based nanomaterials attracts enormous attention owing to the documented antimicrobial properties of these ones. This study reports the extracellular biosynthesis of silver nanoparticles (Ag-NPs) using a Pseudomonas aeruginosa strain from a reference culture collection. A greenish culture supernatant of P. aeruginosa incubated at 37°C with a silver nitrate solution for 24 h changed to a yellowish brown color, indicating the formation of Ag-NPs, which was confirmed by UV-vis spectroscopy, transmission electron microscopy, and X-ray diffraction. TEM analysis showed spherical and pseudospherical nanoparticles with a distributed size mainly between 25 and 45 nm, and the XRD pattern revealed the crystalline nature of Ag-NPs. Also it provides an evaluation of the antimicrobial activity of the biosynthesized Ag-NPs against human pathogenic and opportunistic microorganisms, namely, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Proteus mirabilis, Acinetobacter baumannii, Escherichia coli, P. aeruginosa, and Klebsiella pneumonia. Ag-NPs were found to be bioactive at picomolar concentration levels showing bactericidal effects against both Gram-positive and Gram-negative bacterial strains. This work demonstrates the first helpful use of biosynthesized Ag-NPs as broad spectrum bactericidal agents for clinical strains of pathogenic multidrug-resistant bacteria such as methicillin-resistant S. aureus, A. baumannii, and E. coli. In addition, these Ag-NPs showed negligible cytotoxic effect in human neutrophils suggesting low toxicity to the host. PMID:27340405

  9. Characterization of five newly isolated bacteriophages active against Pseudomonas aeruginosa clinical strains.

    PubMed

    Kwiatek, Magdalena; Mizak, Lidia; Parasion, Sylwia; Gryko, Romuald; Olender, Alina; Niemcewicz, Marcin

    2015-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that causes serious infections, especially in patients with immunodeficiency. It exhibits multiple mechanisms of resistance, including efflux pumps, antibiotic modifying enzymes and limited membrane permeability. The primary reason for the development of novel therapeutics for P. aeruginosa infections is the declining efficacy of conventional antibiotic therapy. These clinical problems caused a revitalization of interest in bacteriophages, which are highly specific and have very effective antibacterial activity as well as several other advantages over traditional antimicrobial agents. Above all, so far, no serious or irreversible side effects of phage therapy have been described. Five newly purified P. aeruginosa phages named vB_PaeM_WP1, vB_PaeM_WP2, vB_PaeM_WP3, vB_PaeM_WP4 and vB_PaeP_WP5 have been characterized as potential candidates for use in phage therapy. They are representatives of the Myoviridae and Podoviridae families. Their host range, genome size, structural proteins and stability in various physical and chemical conditions were tested. The results of these preliminary investigations indicate that the newly isolated bacteriophages may be considered for use in phagotherapy.

  10. Sodium houttuyfonate inhibits biofilm formation and alginate biosynthesis-associated gene expression in a clinical strain of Pseudomonas aeruginosa in vitro

    PubMed Central

    WU, DA-QIANG; CHENG, HUIJUAN; DUAN, QIANGJUN; HUANG, WEIFENG

    2015-01-01

    The increasing multidrug resistance of Pseudomonas aeruginosa has become a serious public-health problem. In the present study, the inhibitory activities of sodium houttuyfonate (SH) against biofilm formation and alginate production in a clinical strain of P. aeruginosa (AH16) were investigated in vitro using crystal violet dying and standard curve methods, respectively. The cellular morphology of P. aeruginosa treated with SH was observed using a scanning electron microscope. Furthermore, reverse transcription-quantitative polymerase chain reaction was used to identify differences in the expression levels of genes associated with alginate biosynthesis as a result of the SH treatment. The results indicated that SH significantly inhibited biofilm formation, and decreased the levels of the primary biofilm constituent, alginate, in P. aeruginosa AH16 at various stages of biofilm development. In addition, scanning electron microscopy observations demonstrated that SH markedly altered the cellular morphology and biofilm structure of P. aeruginosa. Furthermore, the results from the reverse transcription-quantitative polymerase chain reaction analysis indicated that SH inhibited biofilm formation by mitigating the expression of the algD and algR genes, which are associated with alginate biosynthesis. Therefore, the present study has provided novel insights into the potent effects and underlying mechanisms of SH-induced inhibition of biofilm formation in a clinical strain of P. aeruginosa. PMID:26622388

  11. Sodium houttuyfonate inhibits biofilm formation and alginate biosynthesis-associated gene expression in a clinical strain of Pseudomonas aeruginosa in vitro.

    PubMed

    Wu, DA-Qiang; Cheng, Huijuan; Duan, Qiangjun; Huang, Weifeng

    2015-08-01

    The increasing multidrug resistance of Pseudomonas aeruginosa has become a serious public-health problem. In the present study, the inhibitory activities of sodium houttuyfonate (SH) against biofilm formation and alginate production in a clinical strain of P.aeruginosa (AH16) were investigated in vitro using crystal violet dying and standard curve methods, respectively. The cellular morphology of P. aeruginosa treated with SH was observed using a scanning electron microscope. Furthermore, reverse transcription-quantitative polymerase chain reaction was used to identify differences in the expression levels of genes associated with alginate biosynthesis as a result of the SH treatment. The results indicated that SH significantly inhibited biofilm formation, and decreased the levels of the primary biofilm constituent, alginate, in P. aeruginosa AH16 at various stages of biofilm development. In addition, scanning electron microscopy observations demonstrated that SH markedly altered the cellular morphology and biofilm structure of P. aeruginosa. Furthermore, the results from the reverse transcription-quantitative polymerase chain reaction analysis indicated that SH inhibited biofilm formation by mitigating the expression of the algD and algR genes, which are associated with alginate biosynthesis. Therefore, the present study has provided novel insights into the potent effects and underlying mechanisms of SH-induced inhibition of biofilm formation in a clinical strain of P. aeruginosa.

  12. Structural basis for effectiveness of siderophore-conjugated monocarbams against clinically relevant strains of Pseudomonas aeruginosa

    SciTech Connect

    Han, Seungil; Zaniewski, Richard P.; Marr, Eric S.; Lacey, Brian M.; Tomaras, Andrew P.; Evdokimov, Artem; Miller, J. Richard; Shanmugasundaram, Veerabahu

    2012-02-08

    Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen that causes nosocomial infections for which there are limited treatment options. Penicillin-binding protein PBP3, a key therapeutic target, is an essential enzyme responsible for the final steps of peptidoglycan synthesis and is covalently inactivated by {beta}-lactam antibiotics. Here we disclose the first high resolution cocrystal structures of the P. aeruginosa PBP3 with both novel and marketed {beta}-lactams. These structures reveal a conformational rearrangement of Tyr532 and Phe533 and a ligand-induced conformational change of Tyr409 and Arg489. The well-known affinity of the monobactam aztreonam for P. aeruginosa PBP3 is due to a distinct hydrophobic aromatic wall composed of Tyr503, Tyr532, and Phe533 interacting with the gem-dimethyl group. The structure of MC-1, a new siderophore-conjugated monocarbam complexed with PBP3 provides molecular insights for lead optimization. Importantly, we have identified a novel conformation that is distinct to the high-molecular-weight class B PBP subfamily, which is identifiable by common features such as a hydrophobic aromatic wall formed by Tyr503, Tyr532, and Phe533 and the structural flexibility of Tyr409 flanked by two glycine residues. This is also the first example of a siderophore-conjugated triazolone-linked monocarbam complexed with any PBP. Energetic analysis of tightly and loosely held computed hydration sites indicates protein desolvation effects contribute significantly to PBP3 binding, and analysis of hydration site energies allows rank ordering of the second-order acylation rate constants. Taken together, these structural, biochemical, and computational studies provide a molecular basis for recognition of P. aeruginosa PBP3 and open avenues for future design of inhibitors of this class of PBPs.

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

    PubMed Central

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

    2016-01-01

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

  14. MIC score, a new tool to compare bacterial susceptibility to antibiotics application to the comparison of susceptibility to different penems of clinical strains of Pseudomonas aeruginosa.

    PubMed

    Bretonnière, Cédric; Maitte, Adeline; Caillon, Jocelyne; Potel, Gilles; Boutoille, David; Jacqueline, Cédric; Guitton, Christophe

    2016-11-01

    This study aimed to compare the susceptibility to carbapenems (imipenem, meropenem and doripenem) of clinical strains of Pseudomonas aeruginosa. It also studied whether susceptibility to imipenem or meropenem could predict, reliably, susceptibility to doripenem. Pseudomonal strains were collected from respiratory specimens, half of them from cystic fibrosis patients. MICs were determined according to European Committee on Antimicrobial Susceptibility Testing recommendations. Carbapenems were compared according to the susceptible, intermediate or resistant categories. A new approach also allowed comparing these carbapenems in a 'MIC score' taking into account the differences in breakpoints between drugs. One hundred thirty-nine strains were studied. They were found to be statistically more susceptible to meropenem than to the two other drugs. However, this difference was small: less than one dilution between the agents. This study also highlighted a significant correlation between susceptibility to penems taken in pairs. However, susceptibility to imipenem or meropenem did not reliably predict susceptibility to doripenem. Despite potential differences in resistance mechanisms, the Pseudomonas aeruginosa strains showed close susceptibility to three carbapenems. This was true for both cystic fibrosis patients and others. However, there were variations between strains. That justifies MICs to be determined for each of the three penems. This might be useful in case of elevated MICs and/or for potentially difficult-to-treat infections such as pneumonia in patients with cystic fibrosis patients.

  15. Large-insert genome analysis technology detects structural variation in Pseudomonas aeruginosa clinical strains from cystic fibrosis patients.

    PubMed

    Hayden, Hillary S; Gillett, Will; Saenphimmachak, Channakhone; Lim, Regina; Zhou, Yang; Jacobs, Michael A; Chang, Jean; Rohmer, Laurence; D'Argenio, David A; Palmieri, Anthony; Levy, Ruth; Haugen, Eric; Wong, Gane K S; Brittnacher, Mitch J; Burns, Jane L; Miller, Samuel I; Olson, Maynard V; Kaul, Rajinder

    2008-06-01

    Large-insert genome analysis (LIGAN) is a broadly applicable, high-throughput technology designed to characterize genome-scale structural variation. Fosmid paired-end sequences and DNA fingerprints from a query genome are compared to a reference sequence using the Genomic Variation Analysis (GenVal) suite of software tools to pinpoint locations of insertions, deletions, and rearrangements. Fosmids spanning regions that contain new structural variants can then be sequenced. Clonal pairs of Pseudomonas aeruginosa isolates from four cystic fibrosis patients were used to validate the LIGAN technology. Approximately 1.5 Mb of inserted sequences were identified, including 743 kb containing 615 ORFs that are absent from published P. aeruginosa genomes. Six rearrangement breakpoints and 220 kb of deleted sequences were also identified. Our study expands the "genome universe" of P. aeruginosa and validates a technology that complements emerging, short-read sequencing methods that are better suited to characterizing single-nucleotide polymorphisms than structural variation.

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

    PubMed

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

    2014-08-01

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

  17. First detection in Europe of the metallo-β-lactamase IMP-15 in clinical strains of Pseudomonas putida and Pseudomonas aeruginosa.

    PubMed

    Gilarranz, R; Juan, C; Castillo-Vera, J; Chamizo, F J; Artiles, F; Álamo, I; Oliver, A

    2013-09-01

    In a prospective study (2009-2011) in healthcare institutions from the Canary Islands (Spain), 6 out of 298 carbapenem non-susceptible Pseudomonas aeruginosa isolates produced a metallo-β-lactamase: four IMP-15, two VIM-2 (including one IMP-15-positive isolate) and one VIM-1. Multilocus sequence typing identified the single VIM-1-producing isolate as clone ST111 and two IMP-15-producing isolates as ST606, but, strikingly, bacterial re-identification revealed that the other three isolates (producing IMP-15 and/or VIM-2) were actually Pseudomonas putida. Further retrospective analysis revealed a very high prevalence (close to 50%) of carbapenem resistance in this environmental species. Hence, we report the simultaneous emergence in hospitals on the Canary Islands of P. putida and P. aeruginosa strains producing IMP-15, a metallo-β-lactamase not previously detected in Europe, and suggest an underestimated role of P. putida as a nosocomial reservoir of worrying transferable resistance determinants.

  18. Wide Dispersion of ST175 Clone despite High Genetic Diversity of Carbapenem-Nonsusceptible Pseudomonas aeruginosa Clinical Strains in 16 Spanish Hospitals▿

    PubMed Central

    García-Castillo, María; del Campo, Rosa; Morosini, María Isabel; Riera, Elena; Cabot, Gabriel; Willems, Rob; van Mansfeld, Rosa; Oliver, Antonio; Cantón, Rafael

    2011-01-01

    During the COMParative Activity of Carbapenems Testing (COMPACT) surveillance study, 448 Pseudomonas aeruginosa clinical isolates were obtained from 16 Spanish hospitals. Nonsusceptibility (EUCAST breakpoints) to imipenem (35%), meropenem (33%), and/or doripenem (33%) was observed with 175 isolates (39%). Simultaneous resistance to these three drugs was observed with 126 of the 175 isolates (72%). Except for colistin, high resistance rates were observed among noncarbapenem antibiotics. Clonal relatedness was investigated by pulsed-field gel electrophoresis (PFGE) with SpeI, discriminating 68 patterns. Multilocus sequence typing (MLST) was performed on 84 isolates representing different PFGE types and all participating hospitals. Thirty-nine sequence types (STs) could be distinguished, and of these, ST175 (48 isolates, 10 hospitals), ST646 (16 isolates, 4 hospitals), ST532 (13 isolates, 3 hospitals), and ST111 (13 isolates, 7 hospitals) were the most frequently encountered. Minimum-spanning tree analysis confirmed a wide dissemination of different clones among participant hospitals, particularly ST175. PFGE pattern comparison within the four most frequent STs revealed that ST175 isolates were relatively uniform, while ST646, ST532, and ST111 isolates were highly diverse, with almost every isolate belonging to a unique pulsotype, even when originating from the same center. The population of carbapenem-nonsusceptible P. aeruginosa isolates from 16 hospitals is highly diverse, with one ST (ST175) representing a highly conserved clone disseminated in 10 of the 16 participant hospitals. This ST175 clone should be added to the list of P. aeruginosa clones at high risk for epidemic spread, such as the Liverpool, Manchester, and Melbourne clones previously found in cystic fibrosis patients and ST235 in the nosocomial setting. PMID:21697331

  19. Molecular characterization of carbapenem-resistant Pseudomonas aeruginosa strains isolated from patients with urinary tract infections in Southern Poland.

    PubMed

    Pobiega, Monika; Maciąg, Joanna; Chmielarczyk, Agnieszka; Romaniszyn, Dorota; Pomorska-Wesolowska, Monika; Ziolkowski, Grzegorz; Heczko, Piotr B; Bulanda, Malgorzata; Wojkowska-Mach, Jadwiga

    2015-11-01

    Due to the clinical threat posed by multidrug-resistant (MDR) Pseudomonas aeruginosa and importance of virulence factors produced in infection, 21 carbapenem-resistant P. aeruginosa were analyzed. 42.8% metallo-beta-lactamases-positive strains were identified. 85.7% of strains were meropenem resistant. 14.2% of strains were MDR; 38%, extensively drug-resistant (XDR). ExoY was present in all strains; exoT, in 95.2%; exoS, in 90.5%; exoU, in 47.6%. Eight XDR strains were typed using multilocus sequence typing: 4 as ST235, 2 as ST260, 2 as ST654 and ST234. MDR P. aeruginosa were isolated from hospitalized patients and among those from the community. Our study demonstrates the serious clinical issues posed by MDR P. aeruginosa and underscores the need for new treatment.

  20. The impact of anaerobiosis on strain-dependent phenotypic variations in Pseudomonas aeruginosa.

    PubMed

    Fang, Hao; Toyofuku, Masanori; Kiyokawa, Tatsunori; Ichihashi, Akihiro; Tateda, Kazuhiro; Nomura, Nobuhiko

    2013-01-01

    Bacteria participate in social behaviors by communicating with each other and forming surface-associated biofilms. In Pseudomonas aeruginosa, such social behaviors are affected greatly by the environment. Although P. aeruginosa survive under anaerobic conditions, previous studies indicate that quorum sensing is attenuated under such conditions, and that this leads to decreased activity of extracellular virulence factors as compared to aerobic conditions. Hence it has come into question whether P. aeruginosa are virulent under anaerobic conditions. Here, we compared various phenotypes between PAO1 and clinical isolates under anaerobic conditions. Our data revealed that when grown anaerobically, growth and cell morphology greatly differed among the strains. One of the clinical isolates produced comparable amounts of quorum-sensing signaling molecules and extracellular virulence factors under aerobic and anaerobic conditions, while the other strains showed low production under anaerobic conditions. Biofilm formation also exhibited strain-dependent variations, suggesting that there are several mechanisms that lead to biofilm formation under anaerobic conditions. Taken together, these results indicate that the impact of anaerobiosis on the social interactions of P. aeruginosa is strain dependent, and suggest that multiple regulatory mechanisms are involved in the regulation of quorum sensing and biofilm formation under anaerobic conditions.

  1. Bactericidal activities of cathelicidin LL-37 and select cationic lipids against the hypervirulent Pseudomonas aeruginosa strain LESB58.

    PubMed

    Wnorowska, Urszula; Niemirowicz, Katarzyna; Myint, Melissa; Diamond, Scott L; Wróblewska, Marta; Savage, Paul B; Janmey, Paul A; Bucki, Robert

    2015-07-01

    Pseudomonas aeruginosa Liverpool epidemic strain (LES) infections in cystic fibrosis (CF) patients are associated with transmissibility and increased patient morbidity. This study was designed to assess the in vitro activities of cathelicidin LL-37 peptide (LL-37) and select cationic lipids against Pseudomonas aeruginosa LESB58 in CF sputum and in a setting mimicking the CF airway. We found that LL-37 naturally present in airway surface fluid and some nonpeptide cationic lipid molecules such as CSA-13, CSA-90, CSA-131, and D2S have significant, but broadly differing, bactericidal activities against P. aeruginosa LESB58. We observed strong inhibition of LL-37 bactericidal activity in the presence of purified bacteriophage Pf1, which is highly expressed by P. aeruginosa LES, but the activities of the cationic lipids CSA-13 and CSA-131 were not affected by this polyanionic virus. Additionally, CSA-13 and CSA-131 effectively prevent LESB58 biofilm formation, which is stimulated by Pf1 bacteriophage, DNA, or F-actin. CSA-13 and CSA-131 display strong antibacterial activities against different clinical strains of P. aeruginosa, and their activities against P. aeruginosa LESB58 and Xen5 strains were maintained in CF sputum. These data indicate that synthetic cationic lipids (mimics of natural antimicrobial peptides) are suitable for developing an effective treatment against CF lung P. aeruginosa infections, including those caused by LES strains.

  2. Bactericidal Activities of Cathelicidin LL-37 and Select Cationic Lipids against the Hypervirulent Pseudomonas aeruginosa Strain LESB58

    PubMed Central

    Wnorowska, Urszula; Niemirowicz, Katarzyna; Myint, Melissa; Diamond, Scott L.; Wróblewska, Marta; Savage, Paul B.; Janmey, Paul A.

    2015-01-01

    Pseudomonas aeruginosa Liverpool epidemic strain (LES) infections in cystic fibrosis (CF) patients are associated with transmissibility and increased patient morbidity. This study was designed to assess the in vitro activities of cathelicidin LL-37 peptide (LL-37) and select cationic lipids against Pseudomonas aeruginosa LESB58 in CF sputum and in a setting mimicking the CF airway. We found that LL-37 naturally present in airway surface fluid and some nonpeptide cationic lipid molecules such as CSA-13, CSA-90, CSA-131, and D2S have significant, but broadly differing, bactericidal activities against P. aeruginosa LESB58. We observed strong inhibition of LL-37 bactericidal activity in the presence of purified bacteriophage Pf1, which is highly expressed by P. aeruginosa LES, but the activities of the cationic lipids CSA-13 and CSA-131 were not affected by this polyanionic virus. Additionally, CSA-13 and CSA-131 effectively prevent LESB58 biofilm formation, which is stimulated by Pf1 bacteriophage, DNA, or F-actin. CSA-13 and CSA-131 display strong antibacterial activities against different clinical strains of P. aeruginosa, and their activities against P. aeruginosa LESB58 and Xen5 strains were maintained in CF sputum. These data indicate that synthetic cationic lipids (mimics of natural antimicrobial peptides) are suitable for developing an effective treatment against CF lung P. aeruginosa infections, including those caused by LES strains. PMID:25870055

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

    PubMed Central

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

    2005-01-01

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

  4. Imported PER-1 producing Pseudomonas aeruginosa, PER-1 producing Acinetobacter baumanii and VIM-2-producing Pseudomonas aeruginosa strains in Hungary

    PubMed Central

    Szabó, Dora; Szentandrássy, Julia; Juhász, Zsuzsa; Katona, Katalin; Nagy, Károly; Rókusz, László

    2008-01-01

    Introduction Pseudomonas aeruginosa and Acinetobacter baumanii are important nosocomial pathogens with wide intrinsic resistance. However, due to the dissemination of the acquired resistance mechanisms, such as extended-spectrum beta-lactamase (ESBL) and metallo beta-lactamase (MBL) production, multidrug resistant strains have been isolated more often. Case presentation We report a case of a Hungarian tourist, who was initially hospitalized in Egypt and later transferred to Hungary. On the day of admission PER-1-producing P. aeruginosa, PER-1 producing A. baumannii, SHV-5-producing Klebsiella pneumoniae and VIM-2-producing P. aeruginosa isolates were subcultured from the patient's samples in Hungary. Comparing the pulsed-field gel electrophoresis (PFGE) patterns of the P. aeruginosa strains from the patient to the P. aeruginosa strains occurring in this hospital, we can state that the PER-1-producing P. aeruginosa and VIM-2-producing P. aeruginosa had external origin. Conclusion This is the first report of PER-1-producing P. aeruginosa,and PER-1-producing A. baumanii strains in Hungary. This case highlights the importance of spreading of the beta-lactamase-mediated resistance mechanisms between countries and continents, showing the importance of careful screening and the isolation of patients arriving from a different country. PMID:18513394

  5. 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

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

    PubMed

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

    1999-11-01

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

  7. Evaluating synergy between marbofloxacin and gentamicin in Pseudomonas aeruginosa strains isolated from dogs with otitis externa.

    PubMed

    Jerzsele, Ákos; Pásztiné-Gere, Erzsébet

    2015-03-01

    The aim of this study was to determine antimicrobial susceptibility of Pseudomonas aeruginosa strains to marbofloxacin and gentamicin, and investigate the possible synergistic, additive, indifferent or antagonistic effects between the two agents. P. aeruginosa strains can develop resistance quickly against certain antibiotics if used alone, thus the need emerges to find synergistic combinations. A total of 68 P. aeruginosa strains isolated from dogs were examined. In order to describe interactions between marbofloxacin and gentamicin the checkerboard microdilution method was utilized. The MICs (minimum inhibitory concentrations) for marbofloxacin and gentamicin were in the range 0.25-64 mg/L and 0.25-32 mg/L, respectively. The combination of marbofloxacin and gentamicin was more effective with a MIC range of 0.031-8 mg/L and a MIC90 of 1 mg/L, compared to 16 mg/L for marbofloxacin alone and 8 mg/L for gentamicin alone. The FIC (fractional inhibitory concentration) indices ranged from 0.0945 (pronounced synergy) to 1.0625 (indifference). Synergy between marbofloxacin and gentamicin was found in 33 isolates. The mean FIC index is 0.546, which represents a partial synergistic/additive effect close to the full synergy threshold. In vitro results indicate that marbofloxacin and gentamicin as partially synergistic agents may prove clinically useful in combination therapy against P. aeruginosa infections. Although marbofloxacin is not used in the human practice, the interactions between fluoroquinolones and aminoglycosides may have importance outside the veterinary field.

  8. Increased morbidity associated with chronic infection by an epidemic Pseudomonas aeruginosa strain in CF patients

    PubMed Central

    Al-Aloul, M; Crawley, J; Winstanley, C; Hart, C; Ledson, M; Walshaw, M

    2004-01-01

    Background: Chronic pulmonary infection with transmissible Pseudomonas aeruginosa strains in individuals with cystic fibrosis (CF) has been reported, raising issues of cross infection and patient segregation. The first such strain to be described (the Liverpool epidemic strain, LES) is now widespread in many UK CF centres. However, whether such infection carries a worse prognosis is unknown. To address this, the clinical course of a group of CF patients chronically infected by LES was compared with that in patients harbouring unique strains. Methods: Using P aeruginosa strain genotyping, two cohorts of CF patients attending the Liverpool CF service were identified who were LES positive or negative in 1998 and remained so until 2002. From these, two groups of 12 patients were matched in 1998 for age, spirometric parameters, and nutritional state and their clinical course was followed for 5 years. Patients chronically infected with Burkholderia cepacia were excluded. Results: Patients chronically infected with LES had a greater annual loss of lung function than those not chronically infected by LES (mean difference between groups -4.4% (95% CI -8.1 to -0.9; p<0.02)), and by 2002 their percentage predicted forced expiratory volume in 1 second (FEV1) was worse (mean 65.0% v 82.6%, p<0.03). Their nutritional state also deteriorated over the study period (mean difference between groups in body mass index -0.7 (95% CI -1.2 to -0.2; p<0.01)), such that by 2002 they were malnourished compared with LES negative patients (mean BMI 19.4 v 22.7, p<0.02). Conclusions: Chronic infection with the Liverpool epidemic P aeruginosa strain in CF patients confers a worse prognosis than infection with unique strains alone, confirming the need for patient segregation. Since this strain is common in many CF units, strain identification in all CF centres is essential. This can only be carried out using genomic typing methods. PMID:15047956

  9. Comparative analysis of the volatile metabolomes of Pseudomonas aeruginosa clinical isolates.

    PubMed

    Bean, Heather D; Rees, Christiaan A; Hill, Jane E

    2016-11-21

    Pseudomonas aeruginosa is a nearly ubiquitous Gram-negative organism, well known to occupy a multitude of environmental niches and cause human infections at a variety of bodily sites, due to its metabolic flexibility, secondary to extensive genetic heterogeneity at the species level. Because of its dynamic metabolism and clinical importance, we sought to perform a comparative analysis on the volatile metabolome (the 'volatilome') produced by P. aeruginosa clinical isolates. In this study, we analyzed the headspace volatile molecules of 24 P. aeruginosa clinical isolates grown in vitro, using 2D gas chromatography time-of-flight mass spectrometry (GC  ×  GC-TOFMS). We identified 391 non-redundant compounds that we associate with the growth and metabolism of P. aeruginosa (the 'pan-volatilome'). Of these, 70 were produced by all 24 isolates (the 'core volatilome'), 52 by only a single isolate, and the remaining 269 volatile molecules by a subset. Sixty-five of the detected compounds could be assigned putative compound identifications, of which 43 had not previously been associated with P. aeruginosa. Using the accessory volatile molecules, we determined the inter-strain variation in the metabolomes of these isolates, clustering strains by their metabotypes. Assessing the extent of metabolomic diversity in P. aeruginosa through an analysis of the volatile molecules that it produces is a critical next step in the identification of novel diagnostic or prognostic biomarkers.

  10. Pseudomonas aeruginosa clinical and environmental isolates constitute a single population with high phenotypic diversity

    PubMed Central

    2014-01-01

    Background Pseudomonas aeruginosa is an opportunistic pathogen with a high incidence of hospital infections that represents a threat to immune compromised patients. Genomic studies have shown that, in contrast to other pathogenic bacteria, clinical and environmental isolates do not show particular genomic differences. In addition, genetic variability of all the P. aeruginosa strains whose genomes have been sequenced is extremely low. This low genomic variability might be explained if clinical strains constitute a subpopulation of this bacterial species present in environments that are close to human populations, which preferentially produce virulence associated traits. Results In this work, we sequenced the genomes and performed phenotypic descriptions for four non-human P. aeruginosa isolates collected from a plant, the ocean, a water-spring, and from dolphin stomach. We show that the four strains are phenotypically diverse and that this is not reflected in genomic variability, since their genomes are almost identical. Furthermore, we performed a detailed comparative genomic analysis of the four strains studied in this work with the thirteen previously reported P. aeruginosa genomes by means of describing their core and pan-genomes. Conclusions Contrary to what has been described for other bacteria we have found that the P. aeruginosa core genome is constituted by a high proportion of genes and that its pan-genome is thus relatively small. Considering the high degree of genomic conservation between isolates of P. aeruginosa from diverse environments, including human tissues, some implications for the treatment of infections are discussed. This work also represents a methodological contribution for the genomic study of P. aeruginosa, since we provide a database of the comparison of all the proteins encoded by the seventeen strains analyzed. PMID:24773920

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

    PubMed

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

    2014-05-15

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

  12. Epidemiological characteristics of Pseudomonas aeruginosa strains causing infection in an Italian general hospital. A one-year surveillance.

    PubMed

    Grigis, A; Farina, C; Moioli, F; Parea, M; Cirillo, D M; Goglio, A; Marchiaro, G

    1995-06-01

    During the 1989 calendar year, P. aeruginosa caused clinical infections in 0.46% of patients admitted to Ospedali Riuniti (a general hospital), Bergamo, Italy. Strains (n = 267) of P. aeruginosa were collected during this period, and epidemiological characteristics were studied. The mean prevalence of P. aeruginosa infection in inpatients was 1.1% (range 0.06-7.3), whereas outpatients showed a significantly lower prevalence of infection (0.05%). Strains were recovered from inpatients of surgical wards (n = 126; 47.2%), and outpatients (n = 15; 5.6%). Males were more often affected than females (2.7:1). Infection of the urinary tract was the most common (34.1%). Pseudomonas aeruginosa was also involved in lower respiratory tract infections (18.7%) and septicaemia (17.6%). Four typing methods were performed, i.e. serotyping, antibiotyping, pyocin typing, and restriction endonuclease analysis (REA). Serotypes O:11 and O:6 were endemic in the hospital. Some serotypes correlated with specific clinical wards. Pyocin typing was an unreliable epidemiological tool. However, antibiotyping showed the presence of some epidemic clusters, probably related to the antibiotic consumption of the patients. REA suggested the circulation of edemic P. aeruginosa strains in both the obstetrics and neurosurgery wards.

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

    PubMed Central

    Haynes, William C.; Rhodes, Lenora J.

    1962-01-01

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

  14. Characterization of Toxin-Antitoxin (TA) Systems in Pseudomonas aeruginosa Clinical Isolates in Iran

    PubMed Central

    Savari, Mohammad; Rostami, Soodabeh; Ekrami, Alireza; Bahador, Abbas

    2016-01-01

    Background: Pseudomonas aeruginosa is among the most problematic hospital and community-acquired pathogens. Toxin-antitoxin (TA) systems are maintenance regulatory systems in bacteria and have recently been considered new targets for antimicrobial therapy. The prevalence and transcription of these systems in clinical isolates are still unknown. Objectives: The aim of this study was to characterize three types of TA systems (parDE, relBE, and higBA) among P. aeruginosa clinical isolates. Materials and Methods: We typed our clinical isolates by ERIC-PCR (enterobacterial repetitive intergenic consensus sequence-based polymerase chain reaction) and BOX-PCR. We then investigated 174 P. aeruginosa clinical isolates from three hospitals in Ahvaz, Iran, for the presence of TA system genes, and determined whether these systems were encoded on chromosomes or plasmids by amplification of the flanking regions. Results: Our results showed that in the 174 P. aeruginosa isolates, relBE and higBA were universal, but parDE was less prevalent. Both of the flanking regions of the parDE genes in all positive isolates were amplified. The flanking regions of nearly all relBE genes were amplified. Amplification was observed for the downstream sequence of every higBA locus, as well as for the region upstream of higBA, except in 14 strains. Conclusions: Based on the presence of TA systems in the majority of P. aeruginosa isolates, these could be used as a novel target for antimicrobial therapy. PMID:27099681

  15. First Report of OXA-4, an ESBL Isolated from Pseudomonas aeruginosa a South Indian Strain.

    PubMed

    Kingsley, S A Jemima; Verghese, Susan

    2013-09-01

    The OXA-type β-lactamases are so named because of their oxacillin-hydrolyzing abilities. In this study we characterize an extended spectrum β-lactamase, designated OXA-4, produced by a clinical isolate of Pseudomonas aeruginosa. ESBL production was detected by double disk synergy test. The P. aeruginosa isolate was obtained from endotracheal suction tip of 84 years old male patient diagnosed with CVA and hypertension. ESBL producing OXA β-lactamases was detected by PCR with primers specific to the conserved regions of the coding genes. Iso electric focusing was done to confirm the significance, sequencing the amplified product was also done. In the phenotypic identification, the strain was highly resistant to third generation cephalosporins and also to imipenem. The PCR amplified product for OXA β-lactamase was viewed at 919 bp. The pI point for the same was identified at 7.2. With the help of sequencing the amplified OXA β-lactamase was identified as OXA-4 gene. Here we report P. aeruginosa producing OXA-4 ESBL for the first time in the Indian subcontinent.

  16. Silver(I) complexes with phthalazine and quinazoline as effective agents against pathogenic Pseudomonas aeruginosa strains.

    PubMed

    Glišić, Biljana Đ; Senerovic, Lidija; Comba, Peter; Wadepohl, Hubert; Veselinovic, Aleksandar; Milivojevic, Dusan R; Djuran, Miloš I; Nikodinovic-Runic, Jasmina

    2016-02-01

    Five silver(I) complexes with aromatic nitrogen-containing heterocycles, phthalazine (phtz) and quinazoline (qz), were synthesized, characterized and analyzed by single-crystal X-ray diffraction analysis. Although different AgX salts reacted with phtz, only dinuclear silver(I) complexes of the general formula {[Ag(X-O)(phtz-N)]2(μ-phtz-N,N')2} were formed, X=NO3(-) (1), CF3SO3(-) (2) and ClO4(-) (3). However, reactions of qz with an equimolar amount of AgCF3SO3 and AgBF4 resulted in the formation of polynuclear complexes, {[Ag(CF3SO3-O)(qz-N)]2}n (4) and {[Ag(qz-N)][BF4]}n (5). Complexes 1-5 were evaluated by in vitro antimicrobial studies against a panel of microbial strains that lead to many skin and soft tissue, respiratory, wound and nosocomial infections. The obtained results indicate that all tested silver(I) complexes have good antibacterial activity with MIC (minimum inhibitory concentration) values in the range from 2.9 to 48.0μM against the investigated strains. Among the investigated strains, these complexes were particularly efficient against pathogenic Pseudomonas aeruginosa (MIC=2.9-29μM) and had a marked ability to disrupt clinically relevant biofilms of strains with high inherent resistance to antibiotics. On the other hand, their activity against the fungus Candida albicans was moderate. In order to determine the therapeutic potential of silver(I) complexes 1-5, their antiproliferative effect on the human lung fibroblastic cell line MRC5, has been also evaluated. The binding of complexes 1-5 to the genomic DNA of P. aeruginosa was demonstrated by gel electrophoresis techniques and well supported by molecular docking into the DNA minor groove. All investigated complexes showed an improved cytotoxicity profile in comparison to the clinically used AgNO3.

  17. Co-incubation of Acanthamoeba castellanii with strains of Pseudomonas aeruginosa alters the survival of amoeba.

    PubMed

    Cengiz, A M; Harmis, N; Stapleton, F

    2000-06-01

    Enhanced survival of Acanthamoeba castellanii has previously been reported following co-incubation with a single strain of Pseudomonas aeruginosa. The aim of this study was to evaluate the impact of different strains of P. aeruginosa on amoebae survival. Four contact lens solutions were challenged with A. castellanii for between 6 and 24 h, and survival rates of amoeba were calculated. Subsequently, A. castellanii was co-incubated with different strains of P. aeruginosa (strain 6294, an invasive isolate; 6206, a cytotoxic isolate; and Paer 001, a null isolate). Differences in amoeba survival over time between solutions for each bacterial strain were analysed. Non-neutralized hydrogen peroxide was the most effective system against A. castellani at all time points (P<0.05). Survival rates were not different between multipurpose solutions and neutralized hydrogen peroxide. Co-incubation with P. aeruginosa altered amoeba survival, and maximum survival occurred in the presence of the invasive strain of P. aeruginosa. Enhanced amoeba survival may occur in the presence of certain strains of Gram-negative bacteria, and with certain types of contact lens disinfection systems.

  18. Computerized restriction endonuclease analysis compared with O-serotype and phage type in the epidemiologic fingerprinting of Pseudomonas aeruginosa strains.

    PubMed

    Garaizar, Javier; Latorre, Mikel; López-Molina, Nuria; Laconcha, Idoia; Alberdi, Leire; Rementeria, Aitor; Audicana, Ana; Uliarte, Rosario; Cisterna, Ramón

    1997-04-01

    OBJECTIVE: To assess restriction endonuclease analysis (REA) of chromosomal DNA using SalI enzyme, low-concentration (0.4%) agarose gels and digitalized data management of the REA patterns obtained for the typing of clinical Pseudomonas aeruginosa isolates. METHODS: A group of 67 clinical unrelated isolates from 10 Spanish hospitals was used to study the discriminatory power, reproducibility and typeability of REA typing. RESULTS: A SalI REA pattern consisted of a variety (1--10) of restriction bands in the range between 12.2 and 48.5 kb and an unresolvable smear of low-molecular-weight bands. Forty different SalI REA patterns with an index of discrimination of 0.979 were obtained. Low typeability (91.04%) was the major limitation of REA typing. Analysis of blinded subcultures of eight Pseudomonas aeruginosa strains showed the reproducibility of REA typing to be 87.5%. Combined phenotypic typing (O-serotyping and phage typing) performed on the same group of strains showed comparable discrimination but much lower reproducibility. Isolates selected from five clusters of nosocomial infections in hospitals in the UK were typed by REA typing, and the results show high agreement when compared with conventional phenotypic typing methods in distinguishing between strains. CONCLUSIONS: These data underline the usefulness of REA typing enhanced with digitalized data management for the epidemiologic subtyping of clinical Pseudomonas aeruginosa isolates.

  19. Identification of Novel Genomic Islands in Liverpool Epidemic Strain of Pseudomonas aeruginosa Using Segmentation and Clustering

    PubMed Central

    Jani, Mehul; Mathee, Kalai; Azad, Rajeev K.

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen implicated in a myriad of infections and a leading pathogen responsible for mortality in patients with cystic fibrosis (CF). Horizontal transfers of genes among the microorganisms living within CF patients have led to highly virulent and multi-drug resistant strains such as the Liverpool epidemic strain of P. aeruginosa, namely the LESB58 strain that has the propensity to acquire virulence and antibiotic resistance genes. Often these genes are acquired in large clusters, referred to as “genomic islands (GIs).” To decipher GIs and understand their contributions to the evolution of virulence and antibiotic resistance in P. aeruginosa LESB58, we utilized a recursive segmentation and clustering procedure, presented here as a genome-mining tool, “GEMINI.” GEMINI was validated on experimentally verified islands in the LESB58 strain before examining its potential to decipher novel islands. Of the 6062 genes in P. aeruginosa LESB58, 596 genes were identified to be resident on 20 GIs of which 12 have not been previously reported. Comparative genomics provided evidence in support of our novel predictions. Furthermore, GEMINI unraveled the mosaic structure of islands that are composed of segments of likely different evolutionary origins, and demonstrated its ability to identify potential strain biomarkers. These newly found islands likely have contributed to the hyper-virulence and multidrug resistance of the Liverpool epidemic strain of P. aeruginosa. PMID:27536294

  20. [Effects of different iron concentrations on the growths of a unicellular strain and a colonial strain of Microcystis aeruginosa].

    PubMed

    Wang, Yu-wen; Li, Jian-hong; Fu, Lu; Wu, Min; Weng, Yong-ping; Zhou, Yao-ming

    2009-01-01

    We investigated the growth, photosynthetic efficiency, siderophore production and iron accumulation of two strains of M. aeruginosa, a unicellular strain M. aeruginosa PCC7806 and a colonial strain M. aeruginosa XW01, under iron-limited and iron-replete conditions. The identities of ITS and fur gene sequences of two strains were 95% and 98% respectively.That implied the two strains should be close relatives. Results showed the growths of two strains were severely inhibited under an iron-limited condition. The unicellular strain died in 6 days,whereas the colonial strain could maintain a weak growth in 10 days under the iron-limited condition. PSII maximum light energy transformation (Fv/Fm) of the colonial strain and the unicellular strain were 0.182 +/- 0.014 and 0.160 +/- 0.017, respectively. The colonial strain displayed a higher photosynthetic oxygen evolution than the unicellular strain. Two strains could produce siderophores, which were hydroxamate type. The colonial strain produced more siderophores than unicellular strain under the iron-limited condition.Iron contents of two strains were less than 1/3 cultured in the iron-limited condition than in iron-replete condition, but no obvious difference appeared between the two strains. Our result demonstrated that the colonial strain have a stronger endurance than unicellular strain under the iron-limited condition. As two strains had almost same abilities of iron accumulation, the other physiological mechanisms in the unicellular strain should be more sensitive to lower iron level.

  1. Prevalence, conservation and functional analysis of Yersinia and Escherichia CRISPR regions in clinical Pseudomonas aeruginosa isolates.

    PubMed

    Cady, K C; White, A S; Hammond, J H; Abendroth, M D; Karthikeyan, R S G; Lalitha, P; Zegans, M E; O'Toole, G A

    2011-02-01

    Here, we report the characterization of 122 Pseudomonas aeruginosa clinical isolates from three distinct geographical locations: Dartmouth Hitchcock Medical Center in New Hampshire, USA, the Charles T. Campbell Eye Microbiology Lab at the University of Pittsburgh Medical Center, USA, and the Aravind Eye Hospital in Madurai, India. We identified and located clustered regularly interspaced short palindromic repeats (CRISPR) in 45/122 clinical isolates and sequenced these CRISPR, finding that Yersinia subtype CRISPR regions (33 %) were more prevalent than the Escherichia CRISPR region subtype (6 %) in these P. aeruginosa clinical isolates. Further, we observed 132 unique spacers from these 45 CRISPR that are 100 % identical to prophages or sequenced temperate bacteriophage capable of becoming prophages. Most intriguingly, all of these 132 viral spacers matched to temperate bacteriophage/prophages capable of inserting into the host chromosome, but not to extrachromosomally replicating lytic P. aeruginosa bacteriophage. We next assessed the ability of the more prevalent Yersinia subtype CRISPR regions to mediate resistance to bacteriophage infection or lysogeny by deleting the entire CRISPR region from sequenced strain UCBPP-PA14 and six clinical isolates. We found no change in CRISPR-mediated resistance to bacteriophage infection or lysogeny rate even for CRISPR with spacers 100 % identical to a region of the infecting bacteriophage. Lastly, to show these CRISPR and cas genes were expressed and functional, we demonstrated production of small CRISPR RNAs. This work provides both the first examination to our knowledge of CRISPR regions within clinical P. aeruginosa isolates and a collection of defined CRISPR-positive and -negative strains for further CRISPR and cas gene studies.

  2. R-type pyocin is required for competitive growth advantage between Pseudomonas aeruginosa strains.

    PubMed

    Heo, Yun-Jeong; Chung, In-Young; Choi, Kelly B; Cho, You-Hee

    2007-01-01

    R-type pyocin is a bacteriophage tail-shaped bacteriocin produced by Pseudomonas aeruginosa, but its physiological roles are relatively unknown. Here we describe a role of R-type pyocin in the competitive growth advantages between P. aeruginosa strains. Partial purification and gene disruption revealed that the major killing activity from the culture supernatant of PA14 is attributed to R-type pyocin, neither F-type nor S-type pyocins. These findings may provide insight into the forces governing P. aeruginosa population dynamics to promote and maintain its biodiversity.

  3. Environmentally Endemic Pseudomonas aeruginosa Strains with Mutations in lasR Are Associated with Increased Disease Severity in Corneal Ulcers

    PubMed Central

    Hammond, John H.; Hebert, Wesley P.; Naimie, Amanda; Ray, Kathryn; Van Gelder, Rachel D.; DiGiandomenico, Antonio; Lalitha, Prajna; Srinivasan, Muthiah; Acharya, Nisha R.; Lietman, Thomas; Hogan, Deborah A.

    2016-01-01

    ABSTRACT The Steroids for Corneal Ulcers Trial (SCUT) was a multicenter, international study of bacterial keratitis in which 101 Pseudomonas aeruginosa infections were treated. Twenty-two of 101 P. aeruginosa isolates collected had a colony morphology characteristic of a loss-of-function mutation in lasR, the gene encoding a quorum-sensing master regulator. Ulcers caused by these 22 strains were associated with larger areas of corneal opacification, worse vision, and a lower rate of vision recovery in response to treatment than ulcers caused by the other isolates. The lasR sequences from these isolates each contained one of three nonsynonymous substitutions, and these strains were deficient in production of LasR-regulated protease and rhamnolipids. Replacement of lasR with either of the two most common lasR alleles from the SCUT isolates was sufficient to decrease protease and rhamnolipid production in PA14. Loss of LasR function is associated with increased production of CupA fimbriae, and the LasR-defective isolates exhibited higher production of CupA fimbriae than LasR-intact isolates. Strains with the same lasR mutation were of the same multilocus sequence type, suggesting that LasR-deficient, environmental P. aeruginosa strains were endemic to the area, and infections caused by these strains were associated with worse patient outcomes in the SCUT study. (This study has been registered at ClinicalTrials.gov under registration no. NCT00324168.) IMPORTANCE The LasR transcription factor is an important regulator of quorum sensing in P. aeruginosa and positively controls multiple virulence-associated pathways. The emergence of strains with lasR loss-of-function alleles in chronic disease is well described and is thought to represent a specific adaptation to the host environment. However, the prevalence and virulence of these strains in acute infections remain unclear. This report describes observations revealing that lasR mutants were common among isolates from

  4. The susceptibility of Pseudomonas aeruginosa strains from cystic fibrosis patients to bacteriophages.

    PubMed

    Essoh, Christiane; Blouin, Yann; Loukou, Guillaume; Cablanmian, Arsher; Lathro, Serge; Kutter, Elizabeth; Thien, Hoang Vu; Vergnaud, Gilles; Pourcel, Christine

    2013-01-01

    Phage therapy may become a complement to antibiotics in the treatment of chronic Pseudomonas aeruginosa infection. To design efficient therapeutic cocktails, the genetic diversity of the species and the spectrum of susceptibility to bacteriophages must be investigated. Bacterial strains showing high levels of phage resistance need to be identified in order to decipher the underlying mechanisms. Here we have selected genetically diverse P. aeruginosa strains from cystic fibrosis patients and tested their susceptibility to a large collection of phages. Based on plaque morphology and restriction profiles, six different phages were purified from "pyophage", a commercial cocktail directed against five different bacterial species, including P. aeruginosa. Characterization of these phages by electron microscopy and sequencing of genome fragments showed that they belong to 4 different genera. Among 47 P. aeruginosa strains, 13 were not lysed by any of the isolated phages individually or by pyophage. We isolated two new phages that could lyse some of these strains, and their genomes were sequenced. The presence/absence of a CRISPR-Cas system (Clustered Regularly Interspaced Short Palindromic Repeats and Crisper associated genes) was investigated to evaluate the role of the system in phage resistance. Altogether, the results show that some P. aeruginosa strains cannot support the growth of any of the tested phages belonging to 5 different genera, and suggest that the CRISPR-Cas system is not a major defence mechanism against these lytic phages.

  5. [Performance evaluation of VITEK 2 system in meropenem susceptibility testing of clinical Pseudomonas aeruginosa isolates].

    PubMed

    Acuner, Ibrahim Cağatay; Bayramoğlu, Gülçin; Birinci, Asuman; Cekiç Cihan, Ciğdem; Bek, Yüksel; Durupınar, Belma

    2011-07-01

    Pseudomonas aeruginosa is an important opportunistic pathogen associated with various community-acquired or nosocomial infections. Multi-drug resistant P.aeruginosa strains increasingly cause epidemics and spread in various hospital wards and geographic regions. Carbapenems are among the most effective antimicrobials in the treatment of multi-drug resistant P.aeruginosa infections, and meropenem is the most successful among alternatives in initial therapy. Particularly in severe infections, inappropriate or inadequate initial antimicrobial therapy is independently associated with adverse clinical and economic outcomes. Availability of accurate and rapid susceptibility testing is a priority. Most of the automated microbiology systems can provide rapid results within 8 to 12 hours. In comparison to standard methods, problems in the antimicrobial susceptibility testing of particular microorganisms and antimicrobial agents have been reported for automated microbiology systems. Failures have been reported previously especially in the susceptibility testing of P.aeruginosa versus carbapenem. Most of these studies are designed according to the Food and Drug Administration (FDA, USA) performance analysis scheme (Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test Systems) in a simplified form. However, there are many lacking issues in the design of most of these studies. Among these, insufficient sample size, use of inappropriate reference method, lack of reproducibility testing, and inadequate distribution of study isolates in interpretative categories are of notice. There are only few studies in the literature that evaluate the performance of automated systems in antimicrobial susceptibility testing of carbapenems in clinical P.aeruginosa isolates with a sufficient sample size (n ? 100). However, most of these studies still have one or more major deficiencies in the study design. Furthermore, none of these studies evaluate the performance of

  6. ISOLATION AND PRELIMINARY CHARACTERISTICS OF THREE BACTERIOPHAGES ASSOCIATED WITH A LYSOGENIC STRAIN OF PSEUDOMONAS AERUGINOSA, 12

    PubMed Central

    Feary, Thomas W.; Fisher, Earl; Fisher, Thelma N.

    1964-01-01

    Feary, Thomas W. (Tulane University School of Medicine, New Orleans, La.), Earl Fisher, Jr., and Thelma N. Fisher. Isolation and preliminary characteristics of three bacteriophages associated with a lysogenic strain of Pseudomonas aeruginosa. J. Bacteriol. 87:196–208. 1964.—Three bacteriophages designated 7v, 7m, and 7s were isolated from a lysogenic strain of Pseudomonas aeruginosa designated Ps-7. The three viruses were found to be completely unrelated on the basis of plaque morphology, host range, serology, ultraviolet induction, sensitivity to heat, and particle morphology as revealed by electron microscopy. In addition, it was shown that the three phages were incapable of plaque formation on bacteria other than various strains of P. aeruginosa. Of the three phages, only phage 7v was capable of plaque formation on strain Ps-7. The growth of phage 7v on strain Ps-7 exhibited properties which suggest that this virus arises as the result of mutation in a temperate phage for which strain Ps-7 is lysogenic. Phages 7m and 7s are incapable of plaque formation on strain Ps-7, but are adsorbed at characteristic rates to cell suspensions of strain Ps-7. The relationship between phage 7m and strain Ps-7 was shown to meet the classical criteria for lysogeny. Because phage 7s contains ribonucleic acid as its nucleic acid component, it was concluded that its production by strain Ps-7 and the demonstration of immunity of strain Ps-7 to infection by phage 7s were not sufficient evidence to define the nature of the relationship between phage 7s and P. aeruginosa strain Ps-7. It was observed that under certain conditions the infectious titer of phage 7s preparations are markedly reduced in the presence of ribonuclease. Images PMID:14102854

  7. Optimisation of AP-PCR fingerprinting discriminatory power for clinical isolates of Pseudomonas aeruginosa.

    PubMed

    Dabrowski, Waldemar; Czekajlo-Kolodziej, Urszula; Medrala, Dagmara; Giedrys-Kalemba, Stefania

    2003-01-21

    Recently methods based on analysis of arbitrarily amplified target sites of microorganism genomes have been extensively applied in microbiological studies. The range of their applications is limited by problems with discrimination and reproducibility resulting from lack of standardised and reliable methods of optimisation. By orthogonal-array optimisation most advantageous and optimal parameters for highly discriminatory primers (CagA2+CMVin2) were selected and efficient AP-PCR (arbitrarily primed-polymerase chain reaction) fingerprinting conditions for Pseudomonas aeruginosa isolates were set up. Stable and multiplex amplicon profiles obtained in this study revealed high level of intraspecies DNA polymorphism among 20 analysed clinical strains of P. aeruginosa proving optimised AP-PCR fingerprinting to be useful in epidemiological typing of the species.

  8. Pseudomonas aeruginosa ATCC 9027 is a non-virulent strain suitable for mono-rhamnolipids production.

    PubMed

    Grosso-Becerra, María-Victoria; González-Valdez, Abigail; Granados-Martínez, María-Jessica; Morales, Estefanía; Servín-González, Luis; Méndez, José-Luis; Delgado, Gabriela; Morales-Espinosa, Rosario; Ponce-Soto, Gabriel-Yaxal; Cocotl-Yañez, Miguel; Soberón-Chávez, Gloria

    2016-12-01

    Rhamnolipids produced by Pseudomonas aeruginosa are biosurfactants with a high biotechnological potential, but their extensive commercialization is limited by the potential virulence of P. aeruginosa and by restrictions in producing these surfactants in heterologous hosts. In this work, we report the characterization of P. aeruginosa strain ATCC 9027 in terms of its genome-sequence, virulence, antibiotic resistance, and its ability to produce mono-rhamnolipids when carrying plasmids with different cloned genes from the type strain PAO1. The genes that were expressed from the plasmids are those coding for enzymes involved in the synthesis of this biosurfactant (rhlA and rhlB), as well as the gene that codes for the RhlR transcriptional regulator. We confirm that strain ATCC 9027 forms part of the PA7 clade, but contrary to strain PA7, it is sensitive to antibiotics and is completely avirulent in a mouse model. We also report that strain ATCC 9027 mono-rhamnolipid synthesis is limited by the expression of the rhlAB-R operon. Thus, this strain carrying the rhlAB-R operon produces similar rhamnolipids levels as PAO1 strain. We determined that strain ATCC 9027 with rhlAB-R operon was not virulent to mice. These results show that strain ATCC 9027, expressing PAO1 rhlAB-R operon, has a high biotechnological potential for industrial mono-rhamnolipid production.

  9. Strain- and Substrate-Dependent Redox Mediator and Electricity Production by Pseudomonas aeruginosa

    PubMed Central

    Bosire, Erick M.; Blank, Lars M.

    2016-01-01

    ABSTRACT Pseudomonas aeruginosa is an important, thriving member of microbial communities of microbial bioelectrochemical systems (BES) through the production of versatile phenazine redox mediators. Pure culture experiments with a model strain revealed synergistic interactions of P. aeruginosa with fermenting microorganisms whereby the synergism was mediated through the shared fermentation product 2,3-butanediol. Our work here shows that the behavior and efficiency of P. aeruginosa in mediated current production is strongly dependent on the strain of P. aeruginosa. We compared levels of phenazine production by the previously investigated model strain P. aeruginosa PA14, the alternative model strain P. aeruginosa PAO1, and the BES isolate Pseudomonas sp. strain KRP1 with glucose and the fermentation products 2,3-butanediol and ethanol as carbon substrates. We found significant differences in substrate-dependent phenazine production and resulting anodic current generation for the three strains, with the BES isolate KRP1 being overall the best current producer and showing the highest electrochemical activity with glucose as a substrate (19 μA cm−2 with ∼150 μg ml−1 phenazine carboxylic acid as a redox mediator). Surprisingly, P. aeruginosa PAO1 showed very low phenazine production and electrochemical activity under all tested conditions. IMPORTANCE Microbial fuel cells and other microbial bioelectrochemical systems hold great promise for environmental technologies such as wastewater treatment and bioremediation. While there is much emphasis on the development of materials and devices to realize such systems, the investigation and a deeper understanding of the underlying microbiology and ecology are lagging behind. Physiological investigations focus on microorganisms exhibiting direct electron transfer in pure culture systems. Meanwhile, mediated electron transfer with natural redox compounds produced by, for example, Pseudomonas aeruginosa might enable an

  10. Detection of Pseudomonas aeruginosa from clinical and environmental samples by amplification of the exotoxin A gene using PCR.

    PubMed Central

    Khan, A A; Cerniglia, C E

    1994-01-01

    PCR was used to detect Pseudomonas aeruginosa from water samples by amplifying a 396-bp region of the exotoxin A (ETA) structural gene sequence. The identify of the amplified 396-bp fragment was confirmed by digesting it with PvuI restriction endonuclease, which produced the predicted 246- and 150-bp fragments. Specific primers amplified ETA-positive P. aeruginosa DNA, whereas other species of Pseudomonas and GC-rich bacteria did not yield any 396-bp fragment. The specificity and sensitivity of the assay were 100 and 96%, respectively, which confirms the assay's reliability for diagnostic and epidemiological studies. The assay can detect as few as 5 to 10 cells in a 10-ml water sample or 0.1 pg of P. aeruginosa DNA per reaction mixture (5 microliters) by ethidium bromide staining of an agarose gel. Ten-times-lower concentrations were detected by hybridization with a digoxigenin-labeled oligonucleotide probe internal to the PCR product. With this PCR method, ETA-positive P. aeruginosa was detected in animal cage water samples at a level of 40 cells per ml. This method is rapid and less cumbersome than other diagnostic methods for the identification of P. aeruginosa strains. The method described can be used to detect a low level of P. aeruginosa from environmental and clinical samples without the use of selective media or additional biochemical tests. Images PMID:7986047

  11. Genome Sequences of Three Strains of the Pseudomonas aeruginosa PA7 Clade

    PubMed Central

    Marti, Romain; Cournoyer, Benoit

    2015-01-01

    Draft genome sequences of three P. aeruginosa strains from the PA7 clade are presented here. Their lengths are 6.36 (EML528), 6.44 (EML545), and 6.33 Mb (EML548). Comparisons with the PA7 genome showed 5,113 conserved coding sequences (CDSs), and significant numbers of strain-specific CDSs. Their analysis will improve our understanding of this highly divergent clade. PMID:26586898

  12. Introduction of Pseudomonas aeruginosa mutator phage D3112 into Alcaligenes eutrophus strain CH34.

    PubMed

    Krylov, V; Merlin, C; Toussaint, A

    1995-01-01

    We have investigated the possibility of growing mutator phages from Pseudomonas aeruginosa on various isolates of Alcaligenes eutrophus. Although none out of 10 A. eutrophus strains were susceptible to infection with any of the phages tested, phage D3112 could be readily transferred in our model strain CH34 by means of an RP4::D3112 plasmid. CH34/RP4::D3112 lysogens were stable and produced phages. However, neither mitomycin C nor UV treatment increased the phage yield.

  13. Rapid Classification and Identification of Microcystis aeruginosa Strains Using MALDI–TOF MS and Polygenetic Analysis

    PubMed Central

    Sun, Li-Wei; Jiang, Wen-Jing; Sato, Hiroaki; Kawachi, Masanobu; Lu, Xi-Wu

    2016-01-01

    Matrix-assisted laser desorption–ionization-time-of-flight mass spectrometry (MALDI–TOF MS) was used to establish a rapid, simple, and accurate method to differentiate among strains of Microcystis aeruginosa, one of the most prevalent types of bloom-forming cyanobacteria. M. aeruginosa NIES-843, for which a complete genome has been sequenced, was used to characterize ribosomal proteins as biomarkers and to optimize conditions for observing ribosomal proteins as major peaks in a given mass spectrum. Thirty-one of 52 ribosomal subunit proteins were detected and identified along the mass spectrum. Fifty-five strains of M. aeruginosa from different habitats were analyzed using MALDI–TOF MS; among these samples, different ribosomal protein types were observed. A polygenetic analysis was performed using an unweighted pair-group method with arithmetic means and different ribosomal protein types to classify the strains into five major clades. Two clades primarily contained toxic strains, and the other three clades contained exclusively non-toxic strains. This is the first study to differentiate cyanobacterial strains using MALDI–TOF MS. PMID:27227555

  14. Comparative protein expression in different strains of the bloom-forming cyanobacterium Microcystis aeruginosa.

    PubMed

    Alexova, Ralitza; Haynes, Paul A; Ferrari, Belinda C; Neilan, Brett A

    2011-09-01

    Toxin production in algal blooms presents a significant problem for the water industry. Of particular concern is microcystin, a potent hepatotoxin produced by the unicellular freshwater species Microcystis aeruginosa. In this study, the proteomes of six toxic and nontoxic strains of M. aeruginosa were analyzed to gain further knowledge in elucidating the role of microcystin production in this microorganism. This represents the first comparative proteomic study in a cyanobacterial species. A large diversity in the protein expression profiles of each strain was observed, with a significant proportion of the identified proteins appearing to be strain-specific. In total, 475 proteins were identified reproducibly and of these, 82 comprised the core proteome of M. aeruginosa. The expression of several hypothetical and unknown proteins, including four possible operons was confirmed. Surprisingly, no proteins were found to be produced only by toxic or nontoxic strains. Quantitative proteome analysis using the label-free normalized spectrum abundance factor approach revealed nine proteins that were differentially expressed between toxic and nontoxic strains. These proteins participate in carbon-nitrogen metabolism and redox balance maintenance and point to an involvement of the global nitrogen regulator NtcA in toxicity. In addition, the switching of a previously inactive toxin-producing strain to microcystin synthesis is reported.

  15. [Pseudomonas aeruginosa bacteriaemia: new clinical and therapeutic aspects ].

    PubMed

    Janbon, F; Despaux, E; Lepeu, G; Jonquet, O; Santoni, A; Balmayer, B; Bertrand, A

    1982-06-01

    Fifty one cases of Pseudomonas aeruginosa bacteriaemia observed during the last 12 years are reported. Thirty five patients were over fifty years old; 92 p. cent were admitted for several days and about 50 p. cent were in post-operative period. A previous antibiotherapy and an impaired status are promotive factors. The respiratory or peritoneal origins are the most frequent. All patients were feverish; 24 have had an infectious shock which was inaugural in 12 cases. Seven pneumonitis, 3 endocarditis, one pericarditis and 2 osteitis were observed. An ecthyma gangrenosum was noted in three patients. Mortality was 70 p. cent. Comparison between recovered and died patients improved bad prognosis of old age, post operative period, neoplasic, previous organica weakness and pulmonary or peritoneal origins. Used alone, colimycin has seemed to be more effective than aminosid antibiotics; but their association with betalactamins was better. An in vitro study of the susceptibility of 100 Pseudomonas aeruginosa strains has proved the interest of piperacillin and cefsulodin; azlocillin, cefoperazone and ceftriaxone are just less effective.

  16. Photodynamic inactivation of antibiotic resistant strain of Pseudomonas aeruginosa in vivo

    NASA Astrophysics Data System (ADS)

    Hashimoto, M. C. E.; Toffoli, D. J.; Prates, R. A.; Courrol, Lilia C.; Ribeiro, M. S.

    2009-06-01

    Burns are frequently contamined by pathogenic microorganisms and the widespread occurrence of antibiotic resistant strains of Pseudomonas aeruginosa in hospitals is a matter of growing concern. Hypocrellin B (HB) is a new generation photosensitizer extracted from the fungus Hypocrella bambusae with absorption bands at 460, 546 and 584 nm. Lanthanide ions change the HB molecular structure and a red shift in the absorption band is observed as well as an increase in the singlet oxygen quantum yield. In this study, we report the use of HB:La+3 to kill resistant strain of P. aeruginosa infected burns. Burns were produced on the back of mice and wounds were infected subcutaneously with 1x109 cfu/mL of P. aeruginosa. Three-hours after inoculation, the animals were divided into 4 groups: control, HB:La+3, blue LED and HB:La+3+blue LED. PDT was performed using 10μM HB:La+3 and 500mW light-emitting diode (LED) emitting at λ=470nm+/-20nm during 120s. The animals of all groups were killed and the infected skin was removed for bacterial counting. Mice with photosensitizer alone, light alone or untreated infected wounds presented 1x108 cfu/g while mice PDT-treated showed a reduction of 2 logs compared to untreated control. These results suggest that HB:La+3 associated to blue LED is effective in diminishing antibiotic resistant strain P. aeruginosa in infected burns.

  17. Antibiotic Resistance in Pseudomonas aeruginosa Strains with Increased Mutation Frequency Due to Inactivation of the DNA Oxidative Repair System▿

    PubMed Central

    Mandsberg, L. F.; Ciofu, O.; Kirkby, N.; Christiansen, L. E.; Poulsen, H. E.; Høiby, N.

    2009-01-01

    The chronic Pseudomonas aeruginosa infection of the lungs of cystic fibrosis (CF) patients is characterized by the biofilm mode of growth and chronic inflammation dominated by polymorphonuclear leukocytes (PMNs). A high percentage of P. aeruginosa strains show high frequencies of mutations (hypermutators [HP]). P. aeruginosa is exposed to oxygen radicals, both those generated by its own metabolism and especially those released by a large number of PMNs in response to the chronic CF lung infection. Our work therefore focused on the role of the DNA oxidative repair system in the development of HP and antibiotic resistance. We have constructed and characterized mutT, mutY, and mutM mutants in P. aeruginosa strain PAO1. The mutT and mutY mutants showed 28- and 7.5-fold increases in mutation frequencies, respectively, over that for PAO1. These mutators had more oxidative DNA damage (higher levels of 7,8-dihydro-8-oxodeoxyguanosine) than PAO1 after exposure to PMNs, and they developed resistance to antibiotics more frequently. The mechanisms of resistance were increased β-lactamase production and overexpression of the MexCD-OprJ efflux-pump. Mutations in either the mutT or the mutY gene were found in resistant HP clinical isolates from patients with CF, and complementation with wild-type genes reverted the phenotype. In conclusion, oxidative stress might be involved in the development of resistance to antibiotics. We therefore suggest the possible use of antioxidants for CF patients to prevent the development of antibiotic resistance. PMID:19332676

  18. Nanoscale analysis of the effects of antibiotics and CX1 on a Pseudomonas aeruginosa multidrug-resistant strain

    NASA Astrophysics Data System (ADS)

    Formosa, C.; Grare, M.; Jauvert, E.; Coutable, A.; Regnouf-de-Vains, J. B.; Mourer, M.; Duval, R. E.; Dague, E.

    2012-08-01

    Drug resistance is a challenge that can be addressed using nanotechnology. We focused on the resistance of the bacteria Pseudomonas aeruginosa and investigated, using Atomic Force Microscopy (AFM), the behavior of a reference strain and of a multidrug resistant clinical strain, submitted to two antibiotics and to an innovative antibacterial drug (CX1). We measured the morphology, surface roughness and elasticity of the bacteria under physiological conditions and exposed to the antibacterial molecules. To go further in the molecules action mechanism, we explored the bacterial cell wall nanoscale organization using functionalized AFM tips. We have demonstrated that affected cells have a molecularly disorganized cell wall; surprisingly long molecules being pulled off from the cell wall by a lectin probe. Finally, we have elucidated the mechanism of action of CX1: it destroys the outer membrane of the bacteria as demonstrated by the results on artificial phospholipidic membranes and on the resistant strain.

  19. ATR-FTIR spectroscopic investigation of imipenem-susceptible and -resistant Pseudomonas aeruginosa isogenic strains.

    PubMed

    Sockalingum, G D; Bouhedja, W; Pina, P; Allouch, P; Mandray, C; Labia, R; Millot, J M; Manfait, M

    1997-03-06

    The primary mechanism of imipenem resistance in Pseudomonas aeruginosa has been ascribed to an outer membrane impermeability owing to a loss of expression of protein D2. Attenuated total reflection-Fourier transform infrared spectroscopy in conjunction with statistical methods has been used as a new approach to rapidly discriminate four isogenic strains of P. aeruginosa--susceptible, less susceptible, and highly resistant to imipenem-- and to follow the structural modifications related to this low permeability. Decomposition of the broad protein and carbohydrate contours into underlying Gaussians and comparison of the susceptible and highly resistant strain provided quantitative and ultrastructural information on these strains. This methodology allows for discrimination not of the mutation itself but of its consequences observed in the protein and carbohydrate absorption regions. Its association with other existing biochemical methods may be envisaged since it may allow for rapid orientation of investigations in the field of bacterial resistance diagnosis.

  20. A Galleria mellonella infection model reveals double and triple antibiotic combination therapies with enhanced efficacy versus a multidrug-resistant strain of Pseudomonas aeruginosa.

    PubMed

    Krezdorn, Jessica; Adams, Sophie; Coote, Peter J

    2014-07-01

    The aim of this study was to compare the inhibitory effect of antibiotic combinations in vitro with efficacy in Galleria mellonella larvae in vivo to identify efficacious combinations that target Pseudomonas aeruginosa. P. aeruginosa NCTC 13437, a multidrug-resistant strain resistant to β-lactams and aminoglycosides, was used. Susceptibility to cefotaxime, piperacillin, meropenem, amikacin, levofloxacin and colistin alone, or in dual or triple combinations, was measured in vitro via a 24 h time-kill assay. In vitro results were then compared with the efficacy of the same dual or triple antibiotic combinations versus G. mellonella larvae infected with P. aeruginosa. G. mellonella haemolymph burden of P. aeruginosa was determined over 96 h post-infection and treatment with the most potent combination therapies. Many dual and triple combinations of antibiotics displayed synergistic inhibition of multidrug-resistant P. aeruginosa in vitro. There was little correlation between combinations that were synergistic in vitro and those that showed enhanced efficacy in vivo versus infected G. mellonella larvae. The most potent dual and triple combinations in vivo were cefotaxime plus piperacillin, and meropenem plus piperacillin and amikacin, respectively. Fewer combinations were found to offer enhanced therapeutic benefit in vivo compared with in vitro. The therapeutic benefit arising from treatment with antibiotic combinations in vivo correlated with reduced larval burden of P. aeruginosa. This study has identified antibiotic combinations that merit further investigation for their clinical potential and has demonstrated the utility of using G. mellonella to screen for novel antibiotic treatments that demonstrate efficacy in vivo.

  1. Strain-dependent diversity in the Pseudomonas aeruginosa quorum-sensing regulon.

    PubMed

    Chugani, Sudha; Kim, Byoung Sik; Phattarasukol, Somsak; Brittnacher, Mitchell J; Choi, Sang Ho; Harwood, Caroline S; Greenberg, E Peter

    2012-10-09

    Quorum sensing allows bacteria to sense and respond to changes in population density. Acyl-homoserine lactones serve as quorum-sensing signals for many Proteobacteria, and acyl-homoserine lactone signaling is known to control cooperative activities. Quorum-controlled activities vary from one species to another. Quorum-sensing controls a constellation of genes in the opportunistic pathogen Pseudomonas aeruginosa, which thrives in a number of habitats ranging from soil and water to animal hosts. We hypothesized that there would be significant variation in quorum-sensing regulons among strains of P. aeruginosa isolated from different habitats and that differences in the quorum-sensing regulons might reveal insights about the ecology of P. aeruginosa. As a test of our hypothesis we used RNA-seq to identify quorum-controlled genes in seven P. aeruginosa isolates of diverse origins. Although our approach certainly overlooks some quorum-sensing-regulated genes we found a shared set of genes, i.e., a core quorum-controlled gene set, and we identified distinct, strain-variable sets of quorum-controlled genes, i.e., accessory genes. Some quorum-controlled genes in some strains were not present in the genomes of other strains. We detected a correlation between traits encoded by some genes in the strain-variable subsets of the quorum regulons and the ecology of the isolates. These findings indicate a role for quorum sensing in extension of the range of habitats in which a species can thrive. This study also provides a framework for understanding the molecular mechanisms by which quorum-sensing systems operate, the evolutionary pressures by which they are maintained, and their importance in disparate ecological contexts.

  2. Genome Sequence of Pseudomonas aeruginosa Strain LCT-PA220, Which Was Selected after Space Flight by Using Biolog's Powerful Carbon Source Utilization Technology.

    PubMed

    Xu, Guogang; Hu, Juan; Fang, Xiangqun; Zhang, Xuelin; Wang, Junfeng; Guo, Yinghua; Li, Tianzhi; Chen, Zhenghong; Dai, Wenkui; Liu, Changting

    2014-03-13

    To explore the changes of Pseudomonas aeruginosa in space flight, we present the draft genome sequence of P. aeruginosa strain LCT-PA220, which originated from a P. aeruginosa strain, ATCC 27853, that traveled on the Shenzhou-VIII spacecraft.

  3. Emerging and existing mechanisms co-operate in generating diverse β-lactam resistance phenotypes in geographically dispersed and genetically disparate Pseudomonas aeruginosa strains.

    PubMed

    Martinez, Elena; Pérez, Javier Escobar; Márquez, Carolina; Vilacoba, Elisabet; Centrón, Daniela; Leal, Aura L; Saavedra, Carlos; Saavedra, Sandra Y; Tovar, Catalina; Vanegas, Natasha; Stokes, H W

    2013-09-01

    β-Lactam resistance in Pseudomonas aeruginosa clinical isolates is driven by a number of mechanisms. Whilst several are understood, how they act co-operatively in pathogenic strains is less clear. In some isolates, resistance profiles cannot always be explained by identifying the common resistance-determining pathways, suggesting that other mechanisms may be important. Pathogenic P. aeruginosa isolates from four countries were characterised by PCR. Quantitative expression analysis was also assessed for the activity of several pathways that influence antibiotic resistance, and culture experiments were conducted to test how random transposition of the insertion sequence IS26 during growth may influence resistance to some antibiotics. In most strains, antibiotic resistance was being driven by changes in multiple pathways and by the presence or absence of genes acquired by lateral gene transfer. Multiple mechanisms of resistance were prevalent in strains from all of the countries examined, although regional differences in the type of interacting mechanisms were apparent. Changes in chromosomal pathways included overexpression of AmpC and two efflux pumps. Also, gain or loss of IS26 at some chromosomal locations, most notably oprD, could influence resistance to carbapenems. IS26-related resistance was found in strains from Argentina and geographically linked Uruguay, but not in strains from either Colombia or Australia. Pseudomonas aeruginosa pathogenic strains are evolving to become multidrug-resistant in more complex ways. This is being influenced by single strains acquiring changes in numerous known pathways as well as by newly emerging resistance mechanisms in this species.

  4. Identification of extensive drug resistant Pseudomonas aeruginosa strains: New clone ST1725 and high-risk clone ST233.

    PubMed

    Aguilar-Rodea, Pamela; Zúñiga, Gerardo; Rodríguez-Espino, Benjamín Antonio; Olivares Cervantes, Alma Lidia; Gamiño Arroyo, Ana Estela; Moreno-Espinosa, Sarbelio; de la Rosa Zamboni, Daniela; López Martínez, Briceida; Castellanos-Cruz, María Del Carmen; Parra-Ortega, Israel; Jiménez Rojas, Verónica Leticia; Vigueras Galindo, Juan Carlos; Velázquez-Guadarrama, Norma

    2017-01-01

    Several microorganisms produce nosocomial infections (NIs), among which Pseudomonas aeruginosa stands out as an opportunist pathogen with the capacity to develop multiresistance to first-choice antibiotics. From 2007 to 2013, forty-six NIs produced by P. aeruginosa were detected at a pediatric tertiary care hospital in Mexico with a significant mortality rate (17.39%). All isolates (n = 58/46 patients) were characterized by evaluating their response to several antibiotics as panresistant (PDR), extensively resistant (XDR), multiresistant (MDR) or sensitive (S). In addition, all isolates were typified through multilocus sequencing of seven genes: acsA, aroE, guaA, mutL, nuoD, ppsA and trpE. Furthermore, to establish the genetic relationships among these isolates, we carried out a phylogenetic inference analysis using maximum likelihood to construct a phylogenetic network. To assess evolutionary parameters, recombination was evaluated using the PHI test, and the ratio of nonsynonymous to synonymous substitutions was determined. Two of the strains were PDR (ST1725); 42 were XDR; four were MDR; and ten were S. Twenty-one new sequence types were detected. Thirty-three strains exhibited novel sequence type ST1725. The ratio of nonsynonym to synonym substitutions was 1:1 considering all genes. Phylogenetic analysis showed that the genetic relationship of the PDR, XDR and MDR strains was mainly clonal; however, the PHI test and the phylogenetic network suggest that recombination events occurred to produce a non-clonal population. This study aimed not only to determine the genetic diversity of clinical P. aeruginosa but also to provide a warning regarding the identification and spreading of clone ST1725, its ability to cause outbreaks with high mortality rates, and to remain in the hospital environment for over seven years. These characteristics highlight the need to identify clonal outbreaks, especially where high resistance to most antibiotics is observed, and control

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

    PubMed

    Abdel-Rhman, Shaymaa Hassan; El-Mahdy, Areej Mostafa; 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.

  6. Conversion of the Pseudomonas aeruginosa Quinolone Signal and Related Alkylhydroxyquinolines by Rhodococcus sp. Strain BG43

    PubMed Central

    Müller, Christine; Birmes, Franziska S.; Niewerth, Heiko

    2014-01-01

    A bacterial strain, which based on the sequences of its 16S rRNA, gyrB, catA, and qsdA genes, was identified as a Rhodococcus sp. closely related to Rhodococcus erythropolis, was isolated from soil by enrichment on the Pseudomonas quinolone signal [PQS; 2-heptyl-3-hydroxy-4(1H)-quinolone], a quorum sensing signal employed by the opportunistic pathogen Pseudomonas aeruginosa. The isolate, termed Rhodococcus sp. strain BG43, cometabolically degraded PQS and its biosynthetic precursor 2-heptyl-4(1H)-quinolone (HHQ) to anthranilic acid. HHQ degradation was accompanied by transient formation of PQS, and HHQ hydroxylation by cell extracts required NADH, indicating that strain BG43 has a HHQ monooxygenase isofunctional to the biosynthetic enzyme PqsH of P. aeruginosa. The enzymes catalyzing HHQ hydroxylation and PQS degradation were inducible by PQS, suggesting a specific pathway. Remarkably, Rhodococcus sp. BG43 is also capable of transforming 2-heptyl-4-hydroxyquinoline-N-oxide to PQS. It thus converts an antibacterial secondary metabolite of P. aeruginosa to a quorum sensing signal molecule. PMID:25239889

  7. Conversion of the Pseudomonas aeruginosa Quinolone Signal and Related Alkylhydroxyquinolines by Rhodococcus sp. Strain BG43.

    PubMed

    Müller, Christine; Birmes, Franziska S; Niewerth, Heiko; Fetzner, Susanne

    2014-12-01

    A bacterial strain, which based on the sequences of its 16S rRNA, gyrB, catA, and qsdA genes, was identified as a Rhodococcus sp. closely related to Rhodococcus erythropolis, was isolated from soil by enrichment on the Pseudomonas quinolone signal [PQS; 2-heptyl-3-hydroxy-4(1H)-quinolone], a quorum sensing signal employed by the opportunistic pathogen Pseudomonas aeruginosa. The isolate, termed Rhodococcus sp. strain BG43, cometabolically degraded PQS and its biosynthetic precursor 2-heptyl-4(1H)-quinolone (HHQ) to anthranilic acid. HHQ degradation was accompanied by transient formation of PQS, and HHQ hydroxylation by cell extracts required NADH, indicating that strain BG43 has a HHQ monooxygenase isofunctional to the biosynthetic enzyme PqsH of P. aeruginosa. The enzymes catalyzing HHQ hydroxylation and PQS degradation were inducible by PQS, suggesting a specific pathway. Remarkably, Rhodococcus sp. BG43 is also capable of transforming 2-heptyl-4-hydroxyquinoline-N-oxide to PQS. It thus converts an antibacterial secondary metabolite of P. aeruginosa to a quorum sensing signal molecule.

  8. Mechanisms of plant growth promotion and disease suppression by Pseudomonas aeruginosa strain 2apa.

    PubMed

    Hariprasad, P; Chandrashekar, S; Singh, S Brijesh; Niranjana, S R

    2014-08-01

    A new Pseudomonas strain, designated as 2apa was isolated from tomato rhizosphere and identified as a member of species Pseudomonas aeruginosa based on its morphology, conventional, biochemical, cell wall fatty acid methyl ester analysis, and 16S rRNA gene sequence analysis. The strain 2apa was positive for root colonization, indole acetic acid (IAA), salicylic acid and siderophore production and inhibited the growth of wide range of microorganisms. Antimicrobial substances produced by this strain with further purification and structure elucidation proved to be phenazine. Under laboratory and greenhouse conditions the strain promoted plant growth and suppressed a wide range of foliar and root pathogens in tomato. The protection offered by strain 2apa to foliar pathogens is considered as induced systemic resistance and was further confirmed by enhanced accumulation of phenolics, elicitation of lipoxygenas activity, and jasmonic acid levels. The broad-spectrum antimicrobial and induced systemic resistance exhibiting strain P. aeruginosa 2apa can be used as an effective biological control candidate against devastating fungal and bacterial pathogens, which attack both root and foliar portions of tomato plant. Production of other functional traits such as IAA and siderophore may enhance its potential as biofertilizer.

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

    PubMed

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

    2016-08-29

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

  10. Fitness Cost of Fluoroquinolone Resistance in Clinical Isolates of Pseudomonas aeruginosa Differs by Type III Secretion Genotype

    PubMed Central

    Agnello, Melissa; Finkel, Steven E.; Wong-Beringer, Annie

    2016-01-01

    Fluoroquinolone (FQ) resistance is highly prevalent among clinical strains of Pseudomonas aeruginosa, limiting treatment options. We have reported previously that highly virulent strains containing the exoU gene of the type III secretion system are more likely to be FQ-resistant than strains containing the exoS gene, as well as more likely to acquire resistance-conferring mutations in gyrA/B and parC/E. We hypothesize that FQ-resistance imposes a lower fitness cost on exoU compared to exoS strains, thus allowing for better adaptation to the FQ-rich clinical environment. We created isogenic mutants containing a common FQ-resistance conferring point mutation in parC from three exoU to three exoS clinical isolates and tested fitness in vitro using head-to-head competition assays. The mutation differentially affected fitness in the exoU and exoS strains tested. While the addition of the parC mutation dramatically increased fitness in one of the exoU strains leaving the other two unaffected, all three exoS strains displayed a general decrease in fitness. In addition, we found that exoU strains may be able to compensate for the fitness costs associated with the mutation through better regulation of supercoiling compared to the exoS strains. These results may provide a biological explanation for the observed predominance of the virulent exoU genotype in FQ-resistant clinical subpopulations and represent the first investigation into potential differences in fitness costs of FQ-resistance that are linked to the virulence genotype of P. aeruginosa. Understanding the fitness costs of antibiotic resistance and possibilities of compensation for these costs is essential for the rational development of strategies to combat the problem of antibiotic resistance. PMID:27757111

  11. Fitness Cost of Fluoroquinolone Resistance in Clinical Isolates of Pseudomonas aeruginosa Differs by Type III Secretion Genotype.

    PubMed

    Agnello, Melissa; Finkel, Steven E; Wong-Beringer, Annie

    2016-01-01

    Fluoroquinolone (FQ) resistance is highly prevalent among clinical strains of Pseudomonas aeruginosa, limiting treatment options. We have reported previously that highly virulent strains containing the exoU gene of the type III secretion system are more likely to be FQ-resistant than strains containing the exoS gene, as well as more likely to acquire resistance-conferring mutations in gyrA/B and parC/E. We hypothesize that FQ-resistance imposes a lower fitness cost on exoU compared to exoS strains, thus allowing for better adaptation to the FQ-rich clinical environment. We created isogenic mutants containing a common FQ-resistance conferring point mutation in parC from three exoU to three exoS clinical isolates and tested fitness in vitro using head-to-head competition assays. The mutation differentially affected fitness in the exoU and exoS strains tested. While the addition of the parC mutation dramatically increased fitness in one of the exoU strains leaving the other two unaffected, all three exoS strains displayed a general decrease in fitness. In addition, we found that exoU strains may be able to compensate for the fitness costs associated with the mutation through better regulation of supercoiling compared to the exoS strains. These results may provide a biological explanation for the observed predominance of the virulent exoU genotype in FQ-resistant clinical subpopulations and represent the first investigation into potential differences in fitness costs of FQ-resistance that are linked to the virulence genotype of P. aeruginosa. Understanding the fitness costs of antibiotic resistance and possibilities of compensation for these costs is essential for the rational development of strategies to combat the problem of antibiotic resistance.

  12. The Effect of Infection Control Nurses on the Occurrence of Pseudomonas aeruginosa Healthcare-Acquired Infection and Multidrug-Resistant Strains in Critically-Ill Children

    PubMed Central

    Xu, Wei; He, Linxi; Liu, Chunfeng; Rong, Jian; Shi, Yongyan; Song, Wenliang; Zhang, Tao; Wang, Lijie

    2015-01-01

    Background Healthcare-acquired Pseudomonas aeruginosa (P. aeruginosa) infections in the Pediatric Intensive Care Unit (PICU), which have a high incidence, increase treatment costs and mortality, and seriously threaten the safety of critically ill children. It is essential to seek convenient and effective methods to control and prevent healthcare-acquired infections (HAIs). This research was conducted to study the effect of infection control nurses on the occurrence of P. aeruginosa HAIs and multi-drug resistance (MDR) strains in PICU. Methods The clinical data was divided into two groups, with the age ranging from 1 month to 14 years. One group of the critically ill patients(N = 3,722) was admitted to PICU from 2007 to 2010, without the management of infection control nurses. The other group of the critically ill patients (N = 3,943) was admitted to PICU from 2011 to 2013, with the management of infection control nurses. Compare the mortality, morbidity and the incidence of acquired P. aeruginosa infections to evaluate the effect of infection control nurses. Results After implementation of the post of infection control nurses, the patient's overall mortality fell from 4.81% to 3.73%. Among the patients with endotracheal intubation more than 48 hours, the incidence of endotracheal intubation-related pneumonia decreased from 44.6% to 34.32%. The mortality of patients with endotracheal intubation decreased from 16.96% to 10.17%, and the morbidity of HAIs with P. aeruginosa decreased from 1.89% to 1.07%. The mutual different rate (MDR) dropped from 67.95% to 44.23%. There were remarkable differences in these rates between the two groups (p<0.05). Conclusion Implementing the post of infection control nurses is associated with effectively reducing the HAI rate, especially the incidence and morbidity of P. aeruginosa HAIs, reducing PICU mortality, improving P. aeruginosa drug resistance. PMID:26630032

  13. Evaluation of the in vitro colistin susceptibility of Pseudomonas aeruginosa and Acinetobacter baumannii strains at a tertiary care centre in Western Turkey.

    PubMed

    Ece, Gulfem; Samlioglu, Pinar; Atalay, Sabri; Kose, Sukran

    2014-03-01

    Multidrug-resistant gram-negative bacteria are an important issue in intensive care units worldwide. Colistin, one of the earliest polymyxin antibiotics, was once widely used for the treatment of gram-negative bacterial infections. However, its use is now limited due to concerns over nephrotoxicity. The appearance of multidrug-resistant species, including A. baumannii and P. aeruginosa, has led to the re-emergence of this class of drugs. The aim of this study was to evaluate the susceptibility of A. baumannii and P. aeruginosa isolates to colistin and other antibiotics. The antimicrobial susceptibility of A. baumannii and P. aeruginosa isolates to colistin and other antibiotics was evaluated between January 2011 and October 2012 at Tepecik Education and Research Hospital in Izmir, Turkey. Clinical isolates were identified using an automatized Vitek 2.0 system. Colistin susceptibility was measured by E-test; the susceptibility profiles of other antibiotics were evaluated using the Kirby Bauer disk-diffusion method. A total of 149 isolates were included in the study, consisting of 98 A. baumannii and 51 P. aeruginosa isolates. The MICs of colistin against A. baumannii were 0.125-2.0 mcg/mL, and 0.25-2.0 mcg/mL against P. aeruginosa; all multidrug-resistant strains examined in this study were susceptible to colistin. Recently, colistin has re-emerged as an effective treatment for infections due to multidrug-resistant A. baumannii, P. aeruginosa, and Klebsiella pneumoniae. All isolates examined in this study were susceptible to colistin, suggesting it could be a viable alternative for the treatment of infections with multidrug-resistant strains.

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

    PubMed Central

    Weng, Lixing; Zhang, Yuqian; Yang, Yuxiang; Wang, Lianhui

    2014-01-01

    Quorum sensing (QS) has been recognized as a general phenomenon in microorganisms and plays an important role in many pathogenic bacteria. In this report, we used the Agrobacterium tumefaciens biosensor strain NT1 to rapidly screen for autoinducer-quenching inhibitors from bacteria. After initial screening 5389 isolates obtained from land and beach soil, 53 putative positive strains were identified. A confirmatory bioassay was carried out after concentrating the putative positive culture supernatant, and 22 strains were confirmed to have anti-LasR activity. Finally, we determined the strain JM2, which could completely inhibit biofilm formation of Pseudomonas aeruginosa PAO1, belonged to the genus Pseudomonas by analysis of 16S rDNA. Partially purified inhibitor factor(s) F5 derived from culture supernatants specifically inhibited LasR-controlled elastase and protease in wild type P. aeruginosa PAO1 by 68% and 73%, respectively, without significantly affecting growth; the rhl-controlled pyocyanin and rhamnolipids were inhibited by 54% and 52% in the presence of 100 μg/mL of F5. The swarming motility and biofilm of PAO1 were also inhibited by F5. Real time RT-PCR on samples from 100 μg/mL F5-treated P. aeruginosa showed downregulation of autoinducer synthase (LasRI and rhlI) and cognate receptor (lasR and rhlR) genes by 50%, 28%, 48%, and 29%, respectively. These results provide compelling evidence that the F5 inhibitor(s) interferes with the las system and significantly inhibits biofilm formation. PMID:24736783

  15. Comparative Profiling of Pseudomonas aeruginosa Strains Reveals Differential Expression of Novel Unique and Conserved Small RNAs

    PubMed Central

    Ferrara, Silvia; Brugnoli, Margherita; De Bonis, Angela; Righetti, Francesco; Delvillani, Francesco; Dehò, Gianni; Horner, David; Briani, Federica; Bertoni, Giovanni

    2012-01-01

    Pseudomonas aeruginosa is a highly adaptable bacterium that thrives in a broad range of ecological niches and can infect multiple hosts as diverse as plants, nematodes and mammals. In humans, it is an important opportunistic pathogen. This wide adaptability correlates with its broad genetic diversity. In this study, we used a deep-sequencing approach to explore the complement of small RNAs (sRNAs) in P. aeruginosa as the number of such regulatory molecules previously identified in this organism is relatively low, considering its genome size, phenotypic diversity and adaptability. We have performed a comparative analysis of PAO1 and PA14 strains which share the same host range but differ in virulence, PA14 being considerably more virulent in several model organisms. Altogether, we have identified more than 150 novel candidate sRNAs and validated a third of them by Northern blotting. Interestingly, a number of these novel sRNAs are strain-specific or showed strain-specific expression, strongly suggesting that they could be involved in determining specific phenotypic traits. PMID:22590564

  16. Production of biosurfactant from a new and promising strain of Pseudomonas aeruginosa PA1.

    PubMed

    Santa Anna, L M; Sebastian, G V; Pereira, N; Alves, T L; Menezes, E P; Freire, D M

    2001-01-01

    The Pseudomonas aeruginosa PA1 strain, isolated from the water of oil production in Sergipe, Northeast Brazil, was evaluated as a potential rhamnolipid type of biosurfactant producer. The production of biosurfactants was investigated using different carbon sources (n-hexadecane, paraffin oil, glycerol, and babassu oil) and inoculum concentrations (0.0016-0.008 g/L). The best results were obtained with glycerol as the substrate and an initial cell concentration of 0.004 g/L. A C:N ratio of 22.8 led to the greatest production of rhamnolipids (1700 mg/L) and efficiency (1.18 g of rhamnolipid/g of dry wt).

  17. Detection of KPC Carbapenemase in Pseudomonas aeruginosa Isolated From Clinical Samples Using Modified Hodge Test and Boronic Acid Phenotypic Methods and Their Comparison With the Polymerase Chain Reaction

    PubMed Central

    Falahat, Saeed; Shojapour, Mana; Sadeghi, Abdorrahim

    2016-01-01

    Background Bacterial resistance to antibiotics has become a major source of concern for public health. Pseudomonas aeruginosa strains are important opportunistic pathogens. These bacteria have a high resistance to a wide range of existing antimicrobials and antibiotics. Objectives The present study was performed to evaluate the frequency of KPC in P. aeruginosa isolated from clinical samples of educational hospitals of Arak University of Medical Sciences, using the mentioned phenotypic and genotypic methods. Materials and Methods One hundred and eight non-duplicate clinical isolates of P. aeruginosa were collected from hospitals of Arak University of Medical Sciences, Arak, Iran. Antibacterial susceptibility was determined by the disk diffusion method. KPC production was confirmed by the Modified Hodge Test (MHT), which is a phenotypic test, and combined-disk test with boronic acid and the Polymerase Chain Reaction (PCR). Results In the present study, 13 isolates (12%) of P. aeruginosa were positive for KPC, using PCR. Comparison of the two phenotypic methods used in this study showed that boronic acid is more sensitive than MHT in identification of KPC-producing strains (84.6% vs. 77%). Conclusions Utilization of reliable methods for identifying carbapenemase-producing strains and determining their antibiotic resistance pattern could have a very important role in treatment of infections caused by these strains. A substantial amount of P. aeruginosa isolated from clinical samples of hospitals in Arak (Iran) produce KPC carbapenemase. Due to their low specificity, MHT and boronic acid phenotypic methods could not completely identify KPC-producing P. aeruginosa. However, the sensitivity of boronic acid phenotypic method in detection of KPC was higher than MHT. PMID:27800140

  18. Proteomic profiling of Pseudomonas aeruginosa AES-1R, PAO1 and PA14 reveals potential virulence determinants associated with a transmissible cystic fibrosis-associated strain

    PubMed Central

    2012-01-01

    Background Pseudomonas aeruginosa is an opportunistic pathogen that is the major cause of morbidity and mortality in patients with cystic fibrosis (CF). While most CF patients are thought to acquire P. aeruginosa from the environment, person-person transmissible strains have been identified in CF clinics worldwide. The molecular basis for transmissibility and colonization of the CF lung remains poorly understood. Results A dual proteomics approach consisting of gel-based and gel-free comparisons were undertaken to analyse protein profiles in a transmissible, early (acute) isolate of the Australian epidemic strain 1 (AES-1R), the virulent burns/wound isolate PA14, and the poorly virulent, laboratory-associated strain PAO1. Over 1700 P. aeruginosa proteins were confidently identified. AES-1R protein profiles revealed elevated abundance of proteins associated with virulence and siderophore biosynthesis and acquisition, antibiotic resistance and lipopolysaccharide and fatty acid biosynthesis. The most abundant protein in AES-1R was confirmed as a previously hypothetical protein with sequence similarity to carbohydrate-binding proteins and database search revealed this gene is only found in the CF-associated strain PA2192. The link with CF infection may suggest that transmissible strains have acquired an ability to rapidly interact with host mucosal glycoproteins. Conclusions Our data suggest that AES-1R expresses higher levels of proteins, such as those involved in antibiotic resistance, iron acquisition and virulence that may provide a competitive advantage during early infection in the CF lung. Identification of novel proteins associated with transmissibility and acute infection may aid in deciphering new strategies for intervention to limit P. aeruginosa infections in CF patients. PMID:22264352

  19. Quality Control for β-Lactam Susceptibility Testing with a Well-Defined Collection of Enterobacteriaceae and Pseudomonas aeruginosa Strains in Spain

    PubMed Central

    Cantón, Rafael; Loza, Elena; Del Carmen Conejo, María; Baquero, Fernando; Martínez-Martínez, Luis

    2003-01-01

    Eighteen Enterobacteriaceae and Pseudomonas aeruginosa strains, 16 of them with well-defined β-lactam re sistance mechanisms, were sent to 52 Spanish microbiology laboratories. Interpretative categories for 8 extended-spectrum β-lactams were collected. Participating laboratories used their own routine susceptibility testing procedures (88% automatic systems, 10% disk diffusion, and 2% agar dilution). Control results were established by two independent reference laboratories by applying the NCCLS microdilution method and interpretative criteria. Interpretative discrepancies were observed in 16% of the results (4.4% for cefepime, 3.0% for aztreonam, 2.8% for piperacillin-tazobactam, 1.7% for cefotaxime [CTX] and ceftazidime, 1.1% for ceftriaxone, 0.9% for meropenem, and 0.3% for imipenem). High consistency with reference values (<5% of major plus very major errors) was observed with (i) American Type Culture Collection quality control strains; (ii) strains with low-efficiency mechanisms inactivating extended-spectrum β-lactams, such as OXA-1-producing Escherichiacoli or SHV-1-hyperproducing Klebsiella pneumoniae; (iii) strains with highly efficient mechanisms, such as SHV-5 porin-deficient K. pneumoniae, CTX-M-10 in Enterobacter cloacae hyperproducing AmpC, and P. aeruginosa with the MexAB OprM efflux phenotype or hyperproducing AmpC. Low consistency (>30% major plus very major errors) was detected in K1-producing Klebsiella oxytoca, CTX-M-9-producing E. coli, and in OprD− P. aeruginosa strains. Extended-spectrum β-lactamase (ESBL)-producing strains accounted for 86% of very major errors. Recognition of the ESBL phenotype was particularly low in Enterobacter cloacae strains (<35%), due to the lack of NCCLS-specific rules in this genus. A K1-producing K. oxytoca was misidentified by 10% of laboratories as an ESBL producer. The use of well-defined resistant strains is useful for improving proficiency in susceptibility testing in clinical laboratories. PMID

  20. Pseudomonas aeruginosa quorum sensing molecules correlate with clinical status in cystic fibrosis.

    PubMed

    Barr, Helen L; Halliday, Nigel; Cámara, Miguel; Barrett, David A; Williams, Paul; Forrester, Douglas L; Simms, Rebecca; Smyth, Alan R; Honeybourne, David; Whitehouse, Joanna L; Nash, Edward F; Dewar, Jane; Clayton, Andrew; Knox, Alan J; Fogarty, Andrew W

    2015-10-01

    Pseudomonas aeruginosa produces quorum sensing signal molecules that are potential biomarkers for infection.A prospective study of 60 cystic fibrosis patients with chronic P. aeruginosa, who required intravenous antibiotics for pulmonary exacerbations, was undertaken. Clinical measurements and biological samples were obtained at the start and end of the treatment period. Additional data were available for 29 of these patients when they were clinically stable.Cross-sectionally, quorum sensing signal molecules were detectable in the sputum, plasma and urine of 86%, 75% and 83% patients, respectively. They were positively correlated between the three biofluids. Positive correlations were observed for most quorum sensing signal molecules in sputum, plasma and urine, with quantitative measures of pulmonary P. aeruginosa load at the start of a pulmonary exacerbation. Plasma concentrations of 2-nonyl-4-hydroxy-quinoline (NHQ) were significantly higher at the start of a pulmonary exacerbation compared to clinical stability (p<0.01). Following the administration of systemic antibiotics, plasma 2-heptyl-4-hydroxyquinoline (p=0.02) and NHQ concentrations (p<0.01) decreased significantly.In conclusion, quorum sensing signal molecules are detectable in cystic fibrosis patients with pulmonary P. aeruginosa infection and are positively correlated with quantitative measures of P. aeruginosa. NHQ correlates with clinical status and has potential as a novel biomarker for P. aeruginosa infection.

  1. Pseudomonas aeruginosa quorum sensing molecules correlate with clinical status in cystic fibrosis

    PubMed Central

    Halliday, Nigel; Cámara, Miguel; Barrett, David A.; Williams, Paul; Forrester, Douglas L.; Simms, Rebecca; Smyth, Alan R.; Honeybourne, David; Whitehouse, Joanna L.; Nash, Edward F.; Dewar, Jane; Clayton, Andrew; Knox, Alan J.; Fogarty, Andrew W.

    2015-01-01

    Pseudomonas aeruginosa produces quorum sensing signal molecules that are potential biomarkers for infection. A prospective study of 60 cystic fibrosis patients with chronic P. aeruginosa, who required intravenous antibiotics for pulmonary exacerbations, was undertaken. Clinical measurements and biological samples were obtained at the start and end of the treatment period. Additional data were available for 29 of these patients when they were clinically stable. Cross-sectionally, quorum sensing signal molecules were detectable in the sputum, plasma and urine of 86%, 75% and 83% patients, respectively. They were positively correlated between the three biofluids. Positive correlations were observed for most quorum sensing signal molecules in sputum, plasma and urine, with quantitative measures of pulmonary P. aeruginosa load at the start of a pulmonary exacerbation. Plasma concentrations of 2-nonyl-4-hydroxy-quinoline (NHQ) were significantly higher at the start of a pulmonary exacerbation compared to clinical stability (p<0.01). Following the administration of systemic antibiotics, plasma 2-heptyl-4-hydroxyquinoline (p=0.02) and NHQ concentrations (p<0.01) decreased significantly. In conclusion, quorum sensing signal molecules are detectable in cystic fibrosis patients with pulmonary P. aeruginosa infection and are positively correlated with quantitative measures of P. aeruginosa. NHQ correlates with clinical status and has potential as a novel biomarker for P. aeruginosa infection. PMID:26022946

  2. Transcriptomic Analyses Elucidate Adaptive Differences of Closely-Related Strains of P. aeruginosa in Fuel.

    PubMed

    Gunasekera, Thusitha S; Bowen, Loryn L; Zhou, Carol E; Howard-Byerly, Susan C; Foley, William S; Striebich, Richard C; Dugan, Larry C; Ruiz, Oscar N

    2017-03-17

    Pseudomonas aeruginosa can utilize hydrocarbons, but different strains have varying degrees of adaptation despite their highly conserved genome. P. aeruginosa ATCC 33988 is highly adapted to hydrocarbons while strain PAO1, a human pathogen, is less-adapted and degrades jet fuel at a slower rate than does ATCC 33988. We investigated fuel specific transcriptomic differences between these strains in order to ascertain the underling mechanisms utilized by the adapted strain to proliferate in fuel. During growth in fuel, the genes related to alkane degradation, heat-shock response, membrane proteins, efflux pumps and several novel genes were upregulated in ATCC 33988. Overexpression of alk genes in PAO1 provided some improvement in growth, but not as robust as that of ATCC 33988, suggesting the role of other genes in adaptation. Expression of the function unknown gene PA5359 from ATCC 33988 in PAO1 increased the growth in fuel. Bioinformatic analysis revealed that PA5359 is a predicted lipoprotein with a conserved 'Yx(FWY)xxD' motif, which is shared among bacterial adhesins. Overexpression of the putative RND-efflux pump PA3521-PA3523 increased the growth of ATCC 33988 strain suggesting a possible role in fuel tolerance. Interestingly the PAO1 strain cannot utilize nC8 and nC10. Expression of GFP under the control of alkB promoters confirmed that alk gene promoter polymorphism affects the expression of alk genes. Promoter fusion assays further confirmed that regulation of alk genes was different in the two strains. Protein sequence analysis showed low amino acid differences for many of the upregulated genes, further supporting transcriptional control as the main mechanism for enhanced adaptation.IMPORTANCE These results support that specific signal transduction, gene regulation and coordination of multiple biological responses are required to improve survival, growth and metabolism of fuel in adapted strains. This study provides new insight into the mechanistic

  3. Identification of extensive drug resistant Pseudomonas aeruginosa strains: New clone ST1725 and high-risk clone ST233

    PubMed Central

    Aguilar-Rodea, Pamela; Zúñiga, Gerardo; Rodríguez-Espino, Benjamín Antonio; Olivares Cervantes, Alma Lidia; Gamiño Arroyo, Ana Estela; Moreno-Espinosa, Sarbelio; de la Rosa Zamboni, Daniela; López Martínez, Briceida; Castellanos-Cruz, María del Carmen; Parra-Ortega, Israel; Jiménez Rojas, Verónica Leticia; Vigueras Galindo, Juan Carlos; Velázquez-Guadarrama, Norma

    2017-01-01

    Several microorganisms produce nosocomial infections (NIs), among which Pseudomonas aeruginosa stands out as an opportunist pathogen with the capacity to develop multiresistance to first-choice antibiotics. From 2007 to 2013, forty-six NIs produced by P. aeruginosa were detected at a pediatric tertiary care hospital in Mexico with a significant mortality rate (17.39%). All isolates (n = 58/46 patients) were characterized by evaluating their response to several antibiotics as panresistant (PDR), extensively resistant (XDR), multiresistant (MDR) or sensitive (S). In addition, all isolates were typified through multilocus sequencing of seven genes: acsA, aroE, guaA, mutL, nuoD, ppsA and trpE. Furthermore, to establish the genetic relationships among these isolates, we carried out a phylogenetic inference analysis using maximum likelihood to construct a phylogenetic network. To assess evolutionary parameters, recombination was evaluated using the PHI test, and the ratio of nonsynonymous to synonymous substitutions was determined. Two of the strains were PDR (ST1725); 42 were XDR; four were MDR; and ten were S. Twenty-one new sequence types were detected. Thirty-three strains exhibited novel sequence type ST1725. The ratio of nonsynonym to synonym substitutions was 1:1 considering all genes. Phylogenetic analysis showed that the genetic relationship of the PDR, XDR and MDR strains was mainly clonal; however, the PHI test and the phylogenetic network suggest that recombination events occurred to produce a non-clonal population. This study aimed not only to determine the genetic diversity of clinical P. aeruginosa but also to provide a warning regarding the identification and spreading of clone ST1725, its ability to cause outbreaks with high mortality rates, and to remain in the hospital environment for over seven years. These characteristics highlight the need to identify clonal outbreaks, especially where high resistance to most antibiotics is observed, and control

  4. Microcyclamide Biosynthesis in Two Strains of Microcystis aeruginosa: from Structure to Genes and Vice Versa▿ †

    PubMed Central

    Ziemert, Nadine; Ishida, Keishi; Quillardet, Philippe; Bouchier, Christiane; Hertweck, Christian; de Marsac, Nicole Tandeau; Dittmann, Elke

    2008-01-01

    Comparative analysis of related biosynthetic gene clusters can provide new insights into the versatility of these pathways and allow the discovery of new natural products. The freshwater cyanobacterium Microcystis aeruginosa NIES298 produces the cytotoxic peptide microcyclamide. Here, we provide evidence that the cyclic hexapeptide is formed by a ribosomal pathway through the activity of a set of processing enzymes closely resembling those recently shown to be involved in patellamide biosynthesis in cyanobacterial symbionts of ascidians. Besides two subtilisin-type proteases and a heterocyclization enzyme, the gene cluster discovered in strain NIES298 encodes six further open reading frames, two of them without similarity to enzymes encoded by the patellamide gene cluster. Analyses of genomic data of a second cyanobacterial strain, M. aeruginosa PCC 7806, guided the discovery and structural elucidation of two novel peptides of the microcyclamide family. The identification of the microcyclamide biosynthetic genes provided an avenue by which to study the regulation of peptide synthesis at the transcriptional level. The precursor genes were strongly and constitutively expressed throughout the growth phase, excluding the autoinduction of these peptides, as has been observed for several peptide pheromone families in bacteria. PMID:18245249

  5. Microcyclamide biosynthesis in two strains of Microcystis aeruginosa: from structure to genes and vice versa.

    PubMed

    Ziemert, Nadine; Ishida, Keishi; Quillardet, Philippe; Bouchier, Christiane; Hertweck, Christian; de Marsac, Nicole Tandeau; Dittmann, Elke

    2008-03-01

    Comparative analysis of related biosynthetic gene clusters can provide new insights into the versatility of these pathways and allow the discovery of new natural products. The freshwater cyanobacterium Microcystis aeruginosa NIES298 produces the cytotoxic peptide microcyclamide. Here, we provide evidence that the cyclic hexapeptide is formed by a ribosomal pathway through the activity of a set of processing enzymes closely resembling those recently shown to be involved in patellamide biosynthesis in cyanobacterial symbionts of ascidians. Besides two subtilisin-type proteases and a heterocyclization enzyme, the gene cluster discovered in strain NIES298 encodes six further open reading frames, two of them without similarity to enzymes encoded by the patellamide gene cluster. Analyses of genomic data of a second cyanobacterial strain, M. aeruginosa PCC 7806, guided the discovery and structural elucidation of two novel peptides of the microcyclamide family. The identification of the microcyclamide biosynthetic genes provided an avenue by which to study the regulation of peptide synthesis at the transcriptional level. The precursor genes were strongly and constitutively expressed throughout the growth phase, excluding the autoinduction of these peptides, as has been observed for several peptide pheromone families in bacteria.

  6. Genome Sequencing of a Mung Bean Plant Growth Promoting Strain of P. aeruginosa with Biocontrol Ability

    PubMed Central

    Illakkiam, Devaraj; Shankar, Manoharan; Ponraj, Paramasivan; Rajendhran, Jeyaprakash

    2014-01-01

    Pseudomonas aeruginosa PGPR2 is a mung bean rhizosphere strain that produces secondary metabolites and hydrolytic enzymes contributing to excellent antifungal activity against Macrophomina phaseolina, one of the prevalent fungal pathogens of mung bean. Genome sequencing was performed using the Ion Torrent Personal Genome Machine generating 1,354,732 reads (6,772,433 sequenced bases) achieving ~25-fold coverage of the genome. Reference genome assembly using MIRA 3.4.0 yielded 198 contigs. The draft genome of PGPR2 encoded 6803 open reading frames, of which 5314 were genes with predicted functions, 1489 were genes of known functions, and 80 were RNA-coding genes. Strain specific and core genes of P. aeruginosa PGPR2 that are relevant to rhizospheric habitat were identified by pangenome analysis. Genes involved in plant growth promoting function such as synthesis of ACC deaminase, indole-3-acetic acid, trehalose, mineral scavenging siderophores, hydrogen cyanide, chitinases, acyl homoserine lactones, acetoin, 2,3-butanediol, and phytases were identified. In addition, niche-specific genes such as phosphate solubilising 3-phytase, adhesins, pathway-specific transcriptional regulators, a diguanylate cyclase involved in cellulose synthesis, a receptor for ferrienterochelin, a DEAD/DEAH-box helicase involved in stress tolerance, chemotaxis/motility determinants, an HtpX protease, and enzymes involved in the production of a chromanone derivative with potent antifungal activity were identified. PMID:25184130

  7. Detection and Genetic Characterization of Metallo-β-Lactamase IMP-1 and VIM-2 in Pseudomonas aeruginosa Strains From Different Hospitals in Kermanshah, Iran

    PubMed Central

    Abiri, Ramin; Mohammadi, Pantea; Shavani, Navid; Rezaei, Mansour

    2015-01-01

    Background: Pseudomonas aeruginosais a frequent nosocomial pathogen that causes severe diseases in many settings. Carbapenems, including meropenem and imipenem, are effective antibiotics against this organism. However, the use of carbapenems has been hampered by the emergence of strains resistant to carbapenemsvia different mechanisms such as the production of metallo-β-lactamases (MBLs), which hydrolyze all carbapenems. Several kinds of MBLs have been reported, among them VIM and IMP types being the most clinically significant carbapenemases. Objectives: We aimed to determine the distribution of blaVIM-2 and blaIMP-1 transferable genes encoding MBLs in P. aeruginosa isolated from three academic hospitals in Kermanshah. Patients and Methods: From 22nd June to 22nd September 2012, 225 isolates of P. aeruginosa were collected. These isolates were tested for antibiotic susceptibility with the Kirby-Bauer disk-diffusion method, and the MBLs were assessed using the imipenem-EDTA double-disk synergy test. The isolates were investigated for blaVIM-2 and blaIMP-1 genes using polymerase chain reaction. Results: Among the 225 isolates, 33.7% (76/225) and 18.1% (41/225) were resistant to imipenem and meropenem, respectively. Of the 76 imipenem-resistant P. aeruginosa strains, 45 (59.2%) were positive for MBLs, 34 (75%) strains carried the blaIMP-1 gene, and 1 (2.2%) strain carried the blaVIM-2 gene. Conclusions: Our results showed that there was a high frequency of IMP-1 positive P. aeruginosa in the different wards of the hospitals. PMID:26495110

  8. Expression of Interleukin-6 in the Cornea in Response to Infection with Different Strains of Pseudomonas aeruginosa

    PubMed Central

    Cole, Nerida; Bao, Shisan; Willcox, Mark; Husband, Alan J.

    1999-01-01

    Strains of Pseudomonas aeruginosa causing keratitis can be either cytotoxic (6206) or invasive (6294), while a strain (Paer1) causing contact lens-induced acute red eye has been shown to be neither. In situ hybridization was used to examine the location and identity of cells expressing interleukin-6 (IL-6) mRNA in the murine cornea and changes in expression in response to infection with different strains of P. aeruginosa. The number of IL-6-positive cells was determined by image analysis. IL-6 protein levels were measured by an enzyme-linked immunosorbent assay. BALB/c mice were challenged by use of the wounded-cornea model with P. aeruginosa 6294, 6206, or Paer1 (2 × 106 CFU). At time intervals up to 24 h, postchallenge corneal tissue was probed for IL-6 mRNA. IL-6 mRNA expression was rapidly elevated in the epithelium in response to strains 6294 and 6206. At the conclusion of the experiments, infiltrating inflammatory cells also stained positively for IL-6 mRNA. In contrast, corneas challenged with strain Paer1 showed significant upregulation of IL-6 mRNA only at 4 h postchallenge. Three distinct patterns of IL-6 mRNA expression in the mouse cornea occur in response to these three ocular isolates of P. aeruginosa. The data obtained for mRNA expression in the cornea for all three strains of P. aeruginosa correlated well with IL-6 protein analysis of whole-eye homogenates. Differences in the cytokine responses to these strains correlate with differences in the pathology associated with each strain and may offer an opportunity to develop strategies for the improved management of ocular inflammation. PMID:10225913

  9. Clinical impact of a highly prevalent Pseudomonas aeruginosa clone in Dutch cystic fibrosis patients.

    PubMed

    de Vrankrijker, A M M; Brimicombe, R W; Wolfs, T F W; Heijerman, H G M; van Mansfeld, R; van Berkhout, F T; Willems, R J L; Bonten, M J M; van der Ent, C K

    2011-03-01

    Studies suggest that infection with highly prevalent Pseudomonas aeruginosa clones in cystic fibrosis (CF) is associated with an unfavourable clinical outcome. We studied the clinical characteristics of patients infected with a recently described, highly prevalent P. aeruginosa clone (ST406) in two CF centres in The Netherlands. Multilocus sequence typing data were available for 219 patients, of whom 40 (18.3%) were infected with ST406 and 179 with other sequence types. ST406 infection was independently associated with age, having a sibling with ST406 infection and use of inhaled antibiotics, but not with unfavourable clinical outcome, suggesting that high transmissibility is not necessarily associated with high virulence.

  10. Streptomycin Accumulation in Susceptible and Resistant Strains of Escherichia coli and Pseudomonas aeruginosa

    PubMed Central

    Bryan, L. E.; Elzen, H. M. Van Den

    1976-01-01

    Streptomycin accumulation by susceptible strains of Escherichia coli and Pseudomonas aeruginosa has been shown to be prevented or inhibited by inhibitors of electron transport, sulfhydryl groups and protein synthesis, and agents that uncouple oxidative phosphorylation. Streptomycin is recovered from cells in an unchanged form and is intracellularly concentrated above extracellular concentrations. Accumulation kinetics are multiphasic; an initial phase which cannot be prevented by the above inhibitors is unable to cause inhibition of cell growth or loss of cell viability. Prevention of further phases of uptake does prevent these events. Inhibitor-susceptible accumulation is time dependent and begins almost immediately upon exposure of cells to streptomycin. Streptomycin accumulation remains energy dependent even when cells are losing acid-soluble [3H]adenine, presumably through loss of permeability control. These results demonstrate that streptomycin accumulation necessary for inhibition of cell growth or cell death requires energy and is not a process of diffusion or secondary to membrane leakage. Streptomycin accumulation in ribosomally resistant mutants of E. coli and P. aeruginosa is similar in that both energy-independent and energy-dependent accumulation can be demonstrated. The total energy-dependent accumulation is, however, significantly lower than that in streptomycin-susceptible cells due to the absence of an additional energy-dependent phase of accumulation, which seems dependent on ribosomal binding of streptomycin. Ribosomally resistant strains can be shown to concentrate streptomycin accumulated by the energy-dependent process above the external concentration in nutrient broth but not in Trypticase soy broth. The energy-dependent accumulation can be saturated in the Strr strain of E. coli in nutrient broth, implying limited accumulation sites. PMID:820248

  11. Reduction and Acetylation of 2,4-Dinitrotoluene by a Pseudomonas aeruginosa Strain.

    PubMed

    Noguera, D R; Freedman, D L

    1996-07-01

    Aerobic and anoxic biotransformation of 2,4-dinitrotoluene (DNT) was examined by using a Pseudomonas aeruginosa strain isolated from a plant treating propellant manufacturing wastewater. DNT biotransformation in the presence and absence of oxygen was mostly reductive and was representative of the type of cometabolic transformations that occur when a high concentration of an easily degradable carbon source is present. P. aeruginosa reduced both nitro groups on DNT, with the formation of mainly 4-amino-2-nitrotoluene and 2-amino-4-nitrotoluene and small quantities of 2,4-diaminotoluene. Acetylation of the arylamines was a significant reaction. 4-Acetamide-2-nitrotoluene and the novel compounds 2-acetamide-4-nitrotoluene, 4-acetamide-2-aminotoluene, and 2,4-diacetamidetoluene were identified as DNT metabolites. The biotransformation of 2,4-diaminotoluene to 4-acetamide-2-aminotoluene was 24 times faster than abiotic transformation. 2-Nitrotoluene and 4-nitrotoluene were also reduced to their corresponding toluidines and then acetylated. However, the yield of 4-acetamidetoluene was much higher than that of 2-acetamidetoluene, demonstrating that acetylation at the position para to the methyl group was favored.

  12. Reduction and Acetylation of 2,4-Dinitrotoluene by a Pseudomonas aeruginosa Strain

    PubMed Central

    Noguera, D. R.; Freedman, D. L.

    1996-01-01

    Aerobic and anoxic biotransformation of 2,4-dinitrotoluene (DNT) was examined by using a Pseudomonas aeruginosa strain isolated from a plant treating propellant manufacturing wastewater. DNT biotransformation in the presence and absence of oxygen was mostly reductive and was representative of the type of cometabolic transformations that occur when a high concentration of an easily degradable carbon source is present. P. aeruginosa reduced both nitro groups on DNT, with the formation of mainly 4-amino-2-nitrotoluene and 2-amino-4-nitrotoluene and small quantities of 2,4-diaminotoluene. Acetylation of the arylamines was a significant reaction. 4-Acetamide-2-nitrotoluene and the novel compounds 2-acetamide-4-nitrotoluene, 4-acetamide-2-aminotoluene, and 2,4-diacetamidetoluene were identified as DNT metabolites. The biotransformation of 2,4-diaminotoluene to 4-acetamide-2-aminotoluene was 24 times faster than abiotic transformation. 2-Nitrotoluene and 4-nitrotoluene were also reduced to their corresponding toluidines and then acetylated. However, the yield of 4-acetamidetoluene was much higher than that of 2-acetamidetoluene, demonstrating that acetylation at the position para to the methyl group was favored. PMID:16535348

  13. Draft Genome Sequence of Pseudomonas aeruginosa Strain N002, Isolated from Crude Oil-Contaminated Soil from Geleky, Assam, India

    PubMed Central

    Roy, Abhjit Sarma; Baruah, Reshita; Gogoi, Dhrubajyoti; Borah, Maina

    2013-01-01

    Here, we report the draft genome sequence of crude oil-degrading Pseudomonas aeruginosa strain N002, isolated from a crude oil-polluted soil sample from Geleky, Assam, India. Multiple genes potentially involved in crude oil degradation were identified. PMID:23405324

  14. Draft Genome Sequence of Pseudomonas aeruginosa Strain Hex1T Isolated from Soils Contaminated with Used Lubricating Oil in Argentina

    PubMed Central

    Luján, Adela M.; Feliziani, Sofía

    2017-01-01

    ABSTRACT Pseudomonas aeruginosa Hex1T was isolated from soils contaminated with used lubricating oil from a garage in Córdoba, Argentina. This strain is capable of utilizing this pollutant as the sole carbon and energy source. Here, we present the 6.9-Mb draft genome sequence of Hex1T, which contains many heavy metal-resistance genes. PMID:28082504

  15. Complete Genome Sequence of the Triclosan- and Multidrug-Resistant Pseudomonas aeruginosa Strain B10W Isolated from Municipal Wastewater

    PubMed Central

    Zhong, Chuanqing; Nelson, Matthew; Cao, Guangxiang

    2017-01-01

    ABSTRACT Here, we report the complete genome sequence of the triclosan- and multidrug-resistant Pseudomonas aeruginosa strain B10W, obtained from municipal wastewater in Hawaii. The bacterium has a 6.7-Mb genome, contains 6,391 coding sequences and 78 RNAs, with an average G+C content of 66.2 mol%. PMID:28104659

  16. 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

  17. Isolation and characterization of an alginase from mucoid strains of Pseudomonas aeruginosa.

    PubMed

    Linker, A; Evans, L R

    1984-09-01

    Strains of Pseudomonas aeruginosa which produce an alginate-like slime polysaccharide were shown to also synthesize an intracellular enzyme which can degrade these polysaccharides and the seaweed alginic acids. The enzyme acts as an eliminase introducing delta 4,5 unsaturation into the uronic acid moiety. It appears to be a polymannuronide lyase which degrades the polysaccharides, depending on their uronic acid composition, to a series of oligosaccharides, the smallest of which is a disaccharide. L-Guluronic acid linkages are not split. The Pseudomonas alginase resembles other bacterial alginases and enzymes from molluscs but differs in some important properties, such as extent of degradation and linkage preference. Nonmucoid forms of the organism produce detectable but much lower amounts of enzyme.

  18. Assessment of the Effects of Light Availability on Growth and Competition Between Strains of Planktothrix agardhii and Microcystis aeruginosa.

    PubMed

    Torres, Camila de Araujo; Lürling, Miquel; Marinho, Marcelo Manzi

    2016-05-01

    In this study, we tested the hypothesis that Planktothrix agardhii strains isolated from a tropical water body were better competitors for light than Microcystis aeruginosa strains. These cyanobacteria are common in eutrophic systems, where light is one of the main drivers of phytoplankton, and Planktothrix is considered more shade-adapted and Microcystis more high-light tolerant. First, the effect of light intensities on growth was studied in batch cultures. Next, the minimum requirement of light (I*) and the effect of light limitation on the outcome of competition was investigated in chemostats. All strains showed similar growth at 10 μmol photons m(-2) s(-1), demonstrating the ability of the two species to grow in low light. The optimum light intensity was lower for P. agardhii, but at the highest light intensity, Microcystis strains reached higher biovolume, confirming that P. agardhii has higher sensitivity to high light. Nonetheless, P. agardhii grew in light intensities considered high (500 μmol photons m(-2) s(-1)) for this species. M. aeruginosa showed a higher carrying capacity in light-limited condition, but I* was similar between all the strains. Under light competition, Microcystis strains displaced P. agardhii and dominated. In two cases, there was competitive exclusion and in the other two P. agardhii managed to remain in the system with a low biovolume (≈15%). Our findings not only show that strains of P. agardhii can grow under higher light intensities than generally assumed but also that strains of M. aeruginosa are better competitors for light than supposed. These results help to understand the co-occurrence of these species in tropical environments and the dominance of M. aeruginosa even in low-light conditions.

  19. Adhesion of Pseudomonas aeruginosa strains to untreated and oxygen-plasma treated poly(vinyl chloride) (PVC) from endotracheal intubation devices.

    PubMed

    Triandafillu, K; Balazs, D J; Aronsson, B-O; Descouts, P; Tu Quoc, P; van Delden, C; Mathieu, H J; Harms, H

    2003-04-01

    Pseudomonas aeruginosa pneumonia is a life threatening complication in mechanically ventilated patients that requires the ability of the bacteria to adhere to, and colonize the endotracheal intubation device. New strategies to prevent or reduce these nosocomial infections are greatly needed. We report here the study of a set of P. aeruginosa clinical isolates, together with specific mutants, regarding their adhesion on native and chemically modified poly(vinyl chloride) (PVC) surfaces from endotracheal intubation devices. The adhesion of the different strains to untreated PVC varied widely, correlating with several physico-chemical characteristics known to influence the attachment of bacteria to inert surfaces. The adhesion patterns were compared to the calculations obtained with the DLVO theory of colloidal stability. These results illustrate the importance of testing different clinical isolates when investigating bacterial adhesion. Oxygen plasma treatment of the PVC pieces yielded a hydrophilic surface and reduced the number of adhering bacteria by as much as 70%. This reduction is however unlikely to be sufficient to prevent P. aeruginosa colonization of endotracheal intubation devices.

  20. Pharmacodynamics of Aerosolized Fosfomycin and Amikacin against Resistant Clinical Isolates of Pseudomonas aeruginosa and Klebsiella pneumoniae in a Hollow-Fiber Infection Model: Experimental Basis for Combination Therapy

    PubMed Central

    Sime, Fekade Bruck; Johnson, Adam; Whalley, Sarah; Santoyo-Castelazo, Anahi; Montgomery, A. Bruce; Walters, Kathie Ann; Lipman, Jeffrey; Hope, William W.

    2016-01-01

    ABSTRACT There has been a resurgence of interest in aerosolization of antibiotics for treatment of patients with severe pneumonia caused by multidrug-resistant pathogens. A combination formulation of amikacin-fosfomycin is currently undergoing clinical testing although the exposure-response relationships of these drugs have not been fully characterized. The aim of this study was to describe the individual and combined antibacterial effects of simulated epithelial lining fluid exposures of aerosolized amikacin and fosfomycin against resistant clinical isolates of Pseudomonas aeruginosa (MICs of 16 mg/liter and 64 mg/liter) and Klebsiella pneumoniae (MICs of 2 mg/liter and 64 mg/liter) using a dynamic hollow-fiber infection model over 7 days. Targeted peak concentrations of 300 mg/liter amikacin and/or 1,200 mg/liter fosfomycin as a 12-hourly dosing regimens were used. Quantitative cultures were performed to describe changes in concentrations of the total and resistant bacterial populations. The targeted starting inoculum was 108 CFU/ml for both strains. We observed that neither amikacin nor fosfomycin monotherapy was bactericidal against P. aeruginosa while both were associated with rapid amplification of resistant P. aeruginosa strains (about 108 to 109 CFU/ml within 24 to 48 h). For K. pneumoniae, amikacin but not fosfomycin was bactericidal. When both drugs were combined, a rapid killing was observed for P. aeruginosa and K. pneumoniae (6-log kill within 24 h). Furthermore, the combination of amikacin and fosfomycin effectively suppressed growth of resistant strains of P. aeruginosa and K. pneumoniae. In conclusion, the combination of amikacin and fosfomycin was effective at maximizing bacterial killing and suppressing emergence of resistance against these clinical isolates. PMID:27795380

  1. Identification and Characterization of a Chitinase Antigen from Pseudomonas aeruginosa Strain 385

    PubMed Central

    Thompson, Suzanne E.; Smith, Mark; Wilkinson, Mark C.; Peek, Keith

    2001-01-01

    A chitinase antigen has been identified in Pseudomonas aeruginosa strain 385 using sera from animals immunized with a whole-cell vaccine. The majority of the activity was shown to be in the cytoplasm, with some activity in the membrane fraction. The chitinase was not secreted into the culture medium. Purification of the enzyme was achieved by exploiting its binding to crab shell chitin. The purified enzyme had a molecular mass of 58 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a pI of 5.2. NH2-terminal amino acid sequencing revealed two sequences of M(I/L)RID and (Q/M/V)AREDAAAAM that gave an exact match to sequences in a translated putative open reading frame from the P. aeruginosa genome. The chitinase was active against chitin azure, ethylene glycol chitin, and colloidal chitin. It did not display any lysozyme activity. Using synthetic 4-methylumbelliferyl chitin substrates, it was shown to be an endochitinase. The Km and kcat for 4-nitrophenyl-β-d-N,N′-diacetylchitobiose were 4.28 mM and 1.7 s−1 respectively, and for 4-nitrophenyl-β-d-N,N′,N′′-triacetylchitotriose, they were 0.48 mM and 0.16 s−1 respectively. The pH optimum was determined to be pH 6.75, and 90% activity was maintained over the pH range 6.5 to 7.1. The enzyme was stable over the pH range 5 to 10 for 3 h and to temperatures up to 50°C for 30 min. The chitinase bound strongly to chitin, chitin azure, colloidal chitin, lichenan, and cellulose but poorly to chitosan, xylan, and heparin. It is suggested that the chitinase functions primarily as a chitobiosidase, removing chitobiose from the nonreducing ends of chitin and chitin oligosaccharides. PMID:11525997

  2. CpxR Activates MexAB-OprM Efflux Pump Expression and Enhances Antibiotic Resistance in Both Laboratory and Clinical nalB-Type Isolates of Pseudomonas aeruginosa

    PubMed Central

    Yi, Xue-Xian; O’Gara, Fergal; Wang, Yi-Ping

    2016-01-01

    Resistance-Nodulation-Division (RND) efflux pumps are responsible for multidrug resistance in Pseudomonas aeruginosa. In this study, we demonstrate that CpxR, previously identified as a regulator of the cell envelope stress response in Escherichia coli, is directly involved in activation of expression of RND efflux pump MexAB-OprM in P. aeruginosa. A conserved CpxR binding site was identified upstream of the mexA promoter in all genome-sequenced P. aeruginosa strains. CpxR is required to enhance mexAB-oprM expression and drug resistance, in the absence of repressor MexR, in P. aeruginosa strains PA14. As defective mexR is a genetic trait associated with the clinical emergence of nalB-type multidrug resistance in P. aeruginosa during antibiotic treatment, we investigated the involvement of CpxR in regulating multidrug resistance among resistant isolates generated in the laboratory via antibiotic treatment and collected in clinical settings. CpxR is required to activate expression of mexAB-oprM and enhances drug resistance, in the absence or presence of MexR, in ofloxacin-cefsulodin-resistant isolates generated in the laboratory. Furthermore, CpxR was also important in the mexR-defective clinical isolates. The newly identified regulatory linkage between CpxR and the MexAB-OprM efflux pump highlights the presence of a complex regulatory network modulating multidrug resistance in P. aeruginosa. PMID:27736975

  3. A novel protein quality control mechanism contributes to heat shock resistance of worldwide-distributed Pseudomonas aeruginosa clone C strains.

    PubMed

    Lee, Changhan; Wigren, Edvard; Trček, Janja; Peters, Verena; Kim, Jihong; Hasni, Muhammad Sharif; Nimtz, Manfred; Lindqvist, Ylva; Park, Chankyu; Curth, Ute; Lünsdorf, Heinrich; Römling, Ute

    2015-11-01

    Pseudomonas aeruginosa is a highly successful nosocomial pathogen capable of causing a wide variety of infections with clone C strains most prevalent worldwide. In this study, we initially characterize a molecular mechanism of survival unique to clone C strains. We identified a P. aeruginosa clone C-specific genomic island (PACGI-1) that contains the highly expressed small heat shock protein sHsp20c, the founding member of a novel subclass of class B bacterial small heat shock proteins. sHsp20c and adjacent gene products are involved in resistance against heat shock. Heat stable sHsp20c is unconventionally expressed in stationary phase in a wide temperature range from 20 to 42°C. Purified sHsp20c has characteristic features of small heat shock protein class B as it is monodisperse, forms sphere-like 24-meric oligomers and exhibits significant chaperone activity. As the P. aeruginosa clone C population is significantly more heat shock resistant than genetically unrelated P. aeruginosa strains without sHsp20c, the horizontally acquired shsp20c operon might contribute to the survival of worldwide-distributed clone C strains.

  4. 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

  5. Enhancement of Rhamnolipid Production in Residual Soybean Oil by an Isolated Strain of Pseudomonas aeruginosa

    NASA Astrophysics Data System (ADS)

    de Lima, C. J. B.; França, F. P.; Sérvulo, E. F. C.; Resende, M. M.; Cardoso, V. L.

    In the present work, the production of rhamnolipid from residual soybean oil (RSO) from food frying facilities was studied using a strain of Pseudomonas aeruginosa of contaminated lagoon, isolated from a hydrocarbon contaminated soil. The optimization of RSO, amonium nitrate, and brewery residual yeast concentrations was accomplished by a central composite experimental design and surface response analysis. The experiments were performed in 500-mL Erlenmeyer flasks containing 50mL of mineral medium, at 170 rpm and 30±1°C, for a 48-h fermentation period. Rhamnolipid production has been monitored by measurements of surface tension, rhamnose concentration, and emulsifying activity. The best-planned results, located on the central point, have corresponded to 22g/L of RSO, 5.625 g/ L of NH4NO3' and 11.5 g/L of brewery yeast. At the maximum point the values for rhamnose and emulsifying index were 2.2g/L and 100%, respectively.

  6. Biodegradation of petroleum hydrocarbons by oleophilic strain of Pseudomonas aeruginosa NCIM 5514.

    PubMed

    Varjani, Sunita J; Upasani, Vivek N

    2016-12-01

    The aim of this work was to study the potential of an indigenous strain of Pseudomonas aeruginosa NCIM 5514, isolated from petroleum-polluted soil, for the biodegradation of crude petroleum oil. The isolate completely decolorized 2,6-dichlorophenol indophenol in 120h when grown at (37±1°C), indicating its hydrocarbon utilizing nature. Ex situ biodegradation study was performed to find out quantitative utilization and biodegradation of paraffin(s) present in crude oil. When the culture was grown in Bushnell-Hass medium containing crude oil (3%,v/v) at 37°C, 180rpm for 60days, the viscosity of the oil was reduced from 1883cp to 1002cp. Gravimetric and gas chromatographic analysis showed 61.03% and 60.63% of biodegradation of C8-C36+ hydrocarbons, respectively. These results indicated that the isolate has potential to be used for ex-situ and in-situ bioremediation of hydrocarbon pollutants and could have promising applications in petrochemical industry.

  7. Biotechnological potential of a rhizosphere Pseudomonas aeruginosa strain producing phenazine-1-carboxylic acid and phenazine-1-carboxamide.

    PubMed

    Zhou, Lian; Jiang, Hai-Xia; Sun, Shuang; Yang, Dan-Dan; Jin, Kai-Ming; Zhang, Wei; He, Ya-Wen

    2016-03-01

    Bacterial phenazine metabolites belong to a group of nitrogen-containing heterocyclic compounds with antimicrobial activities. In this study, a rhizosphere Pseudomonas aeruginosa strain PA1201 was isolated and identified through 16S rDNA sequence analysis and fatty acid profiling. PA1201 inhibited the growth of various pathogenic microorganisms, including Rhizotonia solani, Magnaporthe grisea, Fusarium graminearum, Xanthomonas oryzae pv. oryzae, Xanthomonas oryzae pv. oryzicola, and Staphylococcus aureus. High Performance Liquid Chromatography showed that PA1201 produced high levels of phenazine-1-carboxylic acid (PCA), a registered green fungicide 'Shenqinmycin' with the fermentation titers of 81.7 mg/L in pigment producing medium (PPM) and 926.9 mg/L in SCG medium containing soybean meal, corn steep liquor and glucose. In addition, PA1201 produced another antifungal metabolite, phenazine-1-carboxaminde (PCN), a derivative of PCA, with the fermentation titers of 18.1 and 489.5 mg/L in PPM and SCG medium respectively. To the best of our knowledge, PA1201 is a rhizosphere originating P. aeruginosa strain that congenitally produces the highest levels of PCA and PCN among currently reported P. aeruginosa isolates, which endows it great biotechnological potential to be transformed to a biopesticide-producing engineering strain.

  8. Sensitivity to Antimicrobial Drugs of Pseudomonas Aeruginosa Extreme-Resistant Strains Isolated in the Major Hospitals of Central Kazakhstan

    PubMed Central

    Azizov, Ilya S.; Lavrinenko, Alyona V.; Belyaev, Ilya A.; Babenko, Dmitry B.; Shambilova, Natalya A.; Bissenova, Nelya M.

    2017-01-01

    AIM: The article presents the current data on the sensitivity of the main 37 strains of eXtremaly Drugs Resistance (XDR) category to anti-pseudomonas drugs. MATERIAL AND METHODS: The strains were collected during the prospective multicenter study in large multidisciplinary hospitals of Central Kazakhstan. Susceptibility to antimicrobial drugs was carried out by disk method and the serial dilution method with the interpretation of the results according to EUCAST criteria. Detection of carbapenemases gene of VIM, IMP, NDM and GES classes was carried out by PCR method using the commercial kits. RESULTS: All identified carbapenemases were sorted to VIM class and accounted for 63.64%. Resistance to aminoglycoside drugs exceeded 80%. All the strains were susceptible to polymyxin. CONCLUSION: Thus, at the present stage the circulation of P. aeruginosa strains of XDR category continues in major hospitals in Kazakhstan. The strains remain sensitiveness only to polymyxin. PMID:28293307

  9. Novel rhamnolipid biosurfactants produced by a polycyclic aromatic hydrocarbon-degrading bacterium Pseudomonas aeruginosa strain NY3.

    PubMed

    Nie, Maiqian; Yin, Xihou; Ren, Chunyan; Wang, Yang; Xu, Feng; Shen, Qirong

    2010-01-01

    A novel rhamnolipid biosurfactant-producing and Polycyclic Aromatic Hydrocarbon (PAH)-degrading bacterium Pseudomonas aeruginosa strain NY3 was isolated from petroleum-contaminated soil samples. Strain NY3 was characterized by its extraordinary capacity to produce structurally diverse rhamnolipids. A total of 25 rhamnolipid components and 37 different parent molecular ions, representing various metal ion adducts (Na(+), 2Na(+) and K(+)), were detected by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Among these compounds are ten new rhamnolipids. In addition to its biosurfactant production, strain NY3 was shown to be capable of efficient degradation of PAHs as well as synergistic improvement in the degradation of high molecular weight PAHs by its biosurfactant. These findings have added novel members to the rhamnolipid group and expanded current knowledge regarding the diversity and productive capability of rhamnolipid biosurfactants from a single specific strain with variation of only one carbon source. Additionally, this paper lays the foundation for improvement in the yield of NY3BS and study of the degradation pathway(s) of PAHs in P. aeruginosa strain NY3.

  10. Anti-biofilm activity of biogenic selenium nanoparticles and selenium dioxide against clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis.

    PubMed

    Shakibaie, Mojtaba; Forootanfar, Hamid; Golkari, Yaser; Mohammadi-Khorsand, Tayebe; Shakibaie, Mohammad Reza

    2015-01-01

    The aim of the present study was to investigate the anti-biofilm activity of biologically synthesized selenium nanoparticles (Se NPs) against the biofilm produced by clinically isolated bacterial strains compared to that of selenium dioxide. Thirty strains of Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis were isolated from various specimens of the patients hospitalized in different hospitals (Kerman, Iran). Quantification of the biofilm using microtiter plate assay method introduced 30% of S. aureus, 13% of P. aeruginosa and 17% of P. mirabilis isolates as severely adherent strains. Transmission electron micrograph (TEM) of the purified Se NPs (produced by Bacillus sp. MSh-1) showed individual and spherical nano-structure in the size range of 80-220nm. Obtained results of the biofilm formation revealed that selenium nanoparticles inhibited the biofilm of S. aureus, P. aeruginosa, and P. mirabilis by 42%, 34.3%, and 53.4%, respectively, compared to that of the non-treated samples. Effect of temperature and pH on the biofilm formation in the presence of Se NPs and SeO2 was also evaluated.

  11. Isolation and characterization of a bacteriophage specific for the lipopolysaccharide of rough derivatives of Pseudomonas aeruginosa strain PAO.

    PubMed Central

    Jarrell, K F; Kropinski, A M

    1981-01-01

    A lipopolysaccharide (LPS)-defective (rough) mutant of Pseudomonas aeruginosa PAO was isolated by selection for resistance to the LPS-specific phage E79. The LPS of this mutant, AK-1012, lacked the O-antigenic side chain-specific amino sugar fucosamine as well as the core-specific sugars glucose and rhamnose. Using this strain, we isolated and characterized a phage, phi PLS27, which is specifically inactivated upon incubation with LPS extracted from rough mutants of P. aeruginosa PAO. phi PLS27 was found to be a Bradley type C phage and was very similar to coliphage T7 in a number of properties, including size, buoyant density, mass, and the number of structural proteins. Images PMID:6787214

  12. [Introduction of mutator phage D3112 of Pseudomonas aeruginosa into Alcaligenes eutrophus var. metallotollerans (Strain CH34)].

    PubMed

    Krylov, V N

    1996-01-01

    It is demonstrated that the intact genome of a D3112 tranposable phage (TP) of Pseudomonas aeruginosa, integrated into a recombinant plasmid RP4 :: D3112, can be transferred by means of conjugation from P. putida PpG1 (RP4npt :: D3112) donor cells into Alcaligenes eutrophus var. metallotollerans cells. P. aeruginosa strains are unacceptable as donors because they have a bactericidal effect on A. eutrophus. RP4npt :: D3112 plasmid is stably inherited by A. eutrophus with D3112 being expressed and successfully reproduced. However, TP loses the induction ability after UV irradiation or mitomycin C treatment. It is suggested that D3112 TP and its miniderivatives could be used in manipulations with A. eutrophus var. metallotolerans.

  13. Biodegradation of isoproturon using a novel Pseudomonas aeruginosa strain JS-11 as a multi-functional bioinoculant of environmental significance.

    PubMed

    Dwivedi, Sourabh; Singh, Braj Raj; Al-Khedhairy, Abdulaziz A; Musarrat, Javed

    2011-01-30

    Biodegradation of phenylurea herbicide isoproturon was studied in soil microcosm bioaugmented with a novel bacterial strain JS-11 isolated from wheat rhizosphere. The molecular characterization based on 16SrDNA sequence homology confirmed its identity as Pseudomonas aeruginosa strain JS-11. The herbicide was completely degraded within 20 days at ambient temperature with the rate constant of 0.08 day(-1), following the first-order rate kinetics. In stationary phase, at a cell density of 6.5 × 10(9) CFU mL(-1), the bacteria produced substantially increased amounts of indole acetic acid (IAA) in the presence of tryptophan as compared with the control. Also, the bacteria exhibited a time-dependent increase in the amount of tri-calcium phosphate solubilization in Pikovskaya's medium. Further screening of the strain JS-11 for auxiliary activities revealed its remarkable capability of producing the siderophores and hydrogen cyanide (HCN), besides antifungal activity against a common phytopathogen Fusarium oxysporum. Thus, the versatile P. aeruginosa strain JS-11 with innate potential for multifarious biological activities is envisaged as a super-bioinoculant for exploitation in the integrated bioremediation, plant growth and disease management (IBPDM) in contaminated agricultural soils.

  14. Carbapenem-resistant and cephalosporin-susceptible: a worrisome phenotype among Pseudomonas aeruginosa clinical isolates in Brazil.

    PubMed

    Campana, Eloiza Helena; Xavier, Danilo Elias; Petrolini, Fernanda Villas-Boas; Cordeiro-Moura, Jhonatha Rodrigo; Araujo, Maria Rita Elmor de; Gales, Ana Cristina

    The mechanisms involved in the uncommon resistance phenotype, carbapenem resistance and broad-spectrum cephalosporin susceptibility, were investigated in 25 Pseudomonas aeruginosa clinical isolates that exhibited this phenotype, which were recovered from three different hospitals located in São Paulo, Brazil. The antimicrobial susceptibility profile was determined by CLSI broth microdilution. β-lactamase-encoding genes were investigated by PCR followed by DNA sequencing. Carbapenem hydrolysis activity was investigated by spectrophotometer and MALDI-TOF assays. The mRNA transcription level of oprD was assessed by qRT-PCR and the outer membrane proteins profile was evaluated by SDS-PAGE. Genetic relationship among P. aeruginosa isolates was assessed by PFGE. Carbapenems hydrolysis was not detected by carbapenemase assay in the carbapenem-resistant and cephalosporin-susceptible P. aueruginosa clinical isolates. OprD decreased expression was observed in all P. aeruginosa isolates by qRT-PCR. The outer membrane protein profile by SDS-PAGE suggested a change in the expression of the 46kDa porin that could correspond to OprD porin. The isolates were clustered into 17 genotypes without predominance of a specific PFGE pattern. These results emphasize the involvement of multiple chromosomal mechanisms in carbapenem-resistance among clinical isolates of P. aeruginosa, alert for adaptation of P. aeruginosa clinical isolates under antimicrobial selective pressure and make aware of the emergence of an uncommon phenotype among P. aeruginosa clinical isolates.

  15. Evaluation of Synergistic Interactions Between Cell-Free Supernatant of Lactobacillus Strains and Amikacin and Genetamicin Against Pseudomonas aeruginosa

    PubMed Central

    Aminnezhad, Sargol; Kermanshahi, Rouha Kasra; Ranjbar, Reza

    2015-01-01

    Background: The indiscriminate use of antibiotics in the treatment of infectious diseases can increase the development of antibiotic resistance. Therefore, there is a big demand for new sources of antimicrobial agents and alternative treatments for reduction of antibiotic dosage required to decrease the associated side effects. Objectives: In this study, the synergistic action of aminoglycoside antibiotics and cell-free supernatant (CFS) of probiotic (Lactobacillus rahmnosus and L. casei) against Pseudomonas aeruginosa PTCC 1430 was evaluated. Materials and Methods: A growth medium for culturing of probiotic bacteria was separated by centrifugation. The antimicrobial effects of CFS of probiotic bacteria were evaluated using the agar well diffusion assay. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated using the micro dilution method. Finally, an interaction between CFS and amikacin or gentamicin against P. aeruginosa PTCC 1430 was examined through the checkerboard method and fractional inhibitory concentration (FIC). Furthermore, CFSs from Lactobacillus strains were analyzed by reversed phase HPLC (RP-HPLC) for antimicrobial compounds. Results: The results showed a significant effect of CFS on the growth of P. aeruginosa. The MIC and MBC of CFS from L. casei were 62.5 µL⁄mL while the MIC and MBC of CFS from L. rhamnosus were 62.5 μL⁄mL and 125 μL⁄mL, respectively. Using the FIC indices, synergistic interactions were observed in combination of CFS and antibiotics. Fractional Inhibitory Concentration indices of CFS from L. casei and aminoglycoside antibiotics were 0.124 and 0.312 while FIC indices of CFS from L. rhamnosus and aminoglycoside antibiotics were 0.124 and 0.56, respectively showing a synergism effect. The results of RP-HPLC showed that CFS of Lactobacillus strains contained acetic acid, lactic acid and hydrogen peroxide (H2O2). Conclusions: Our findings indicate that probiotic bacterial

  16. Environmental Pseudomonads Inhibit Cystic Fibrosis Patient-Derived Pseudomonas aeruginosa.

    PubMed

    Chatterjee, Payel; Davis, Elizabeth; Yu, Fengan; James, Sarah; Wildschutte, Julia H; Wiegmann, Daniel D; Sherman, David H; McKay, Robert M; LiPuma, John J; Wildschutte, Hans

    2017-01-15

    Pseudomonas aeruginosa is an opportunistic pathogen which is evolving resistance to many currently used antibiotics. While much research has been devoted to the roles of pathogenic P. aeruginosa in cystic fibrosis (CF) patients, less is known of its ecological properties. P. aeruginosa dominates the lungs during chronic infection in CF patients, yet its abundance in some environments is less than that of other diverse groups of pseudomonads. Here, we sought to determine if clinical isolates of P. aeruginosa are vulnerable to environmental pseudomonads that dominate soil and water habitats in one-to-one competitions which may provide a source of inhibitory factors. We isolated a total of 330 pseudomonads from diverse habitats of soil and freshwater ecosystems and competed these strains against one another to determine their capacity for antagonistic activity. Over 900 individual inhibitory events were observed. Extending the analysis to P. aeruginosa isolates revealed that clinical isolates, including ones with increased alginate production, were susceptible to competition by multiple environmental strains. We performed transposon mutagenesis on one isolate and identified an ∼14.8-kb locus involved in antagonistic activity. Only two other environmental isolates were observed to carry the locus, suggesting the presence of additional unique compounds or interactions among other isolates involved in outcompeting P. aeruginosa This collection of strains represents a source of compounds that are active against multiple pathogenic strains. With the evolution of resistance of P. aeruginosa to currently used antibiotics, these environmental strains provide opportunities for novel compound discovery against drug-resistant clinical strains.

  17. Emergence of NDM – 1 in the Clinical Isolates of Pseudomonas aeruginosa in India

    PubMed Central

    Khajuria, Atul; Praharaj, Ashok Kumar; Kumar, Mahadevan; Grover, Naveen

    2013-01-01

    Objective: The present study was undertaken to detect the prevalence of the blaNDM-1 metallo beta lactamases (MBLs) in the isolates of Pseudomonas aeruginosa, which were recovered from various clinical samples from hospitalized patients in a tertiary care centre in Pune, India. Methods: A total of 200 isolates of P. aeruginosa which were obtained from various clinical samples were subjected to antibiotic susceptibility testing by the disc-diffusion method and their MICs were determined by the Vitek – 2 Automated Antimicrobial Identification and Susceptibility Testing System against imipenem, meropenem, ticarcillin, amikacin, gentamicin, tobramycin, ciprofloxacin, levofloxacin, moxifloxacin, tigecycline, trimethoprim/sulfamethoxazole, ampicillin/sulbactam, piperacillin/tazobactam, cefoperazone/sulbactam, cefepime, tetracycline, ceftazidime, ceftriaxone and colistin. Their MICs were also determined by the Etest method against imipenem, meropenem, piperacillin, tobramycin, ceftazidime, tigecycline and colistin. The presence of blaNDM-1 was detected by PCR and it was confirmed by sequencing the gene which was present in the isolates which exhibited carbapenem resistance. The experimental transferability of the plasmids which carried blaNDM-1 was determined by using E. coli J53 as the recipient. Result: In the present study, four isolates of P. aeruginosa, which carried the blaNDM-1 gene, were resistant to imipenem and meropenem. These blaNDM-1 carrying isolates remained susceptible to colistin. The plasmid carrying blaNDM-1 was successfully transferred from the four isolates to E. coli J53 recipients. Conclusions: We are reporting the emergence of the P. aeruginosa carrying NDM-1gene, which exhibited resistance to imipenem and meropenem, for the first time from India. PMID:23998058

  18. Whole-Genome Sequence of Multidrug-Resistant Pseudomonas aeruginosa Strain BAMCPA07-48, Isolated from a Combat Injury Wound

    PubMed Central

    Sanjar, Fatemeh; Karna, S. L. Rajasekhar; Chen, Tsute; Chen, Ping; Abercrombie, Johnathan J.

    2016-01-01

    We report here the complete genome sequence of Pseudomonas aeruginosa strain BAMCPA07-48, isolated from a combat injury wound. The closed genome sequence of this isolate is a valuable resource for pathogenome characterization of P. aeruginosa associated with wounds, which will aid in the development of a higher-resolution phylogenomic framework for molecular-guided pathogen-surveillance. PMID:27389262

  19. Divergence of a strain of Pseudomonas aeruginosa during an outbreak of ovine mastitis.

    PubMed

    Wright, Elli A; Di Lorenzo, Valeria; Trappetti, Claudia; Liciardi, Manuele; Orru, Germano; Viti, Carlo; Bronowski, Christina; Hall, Amanda J; Darby, Alistair C; Oggioni, Marco R; Winstanley, Craig

    2015-01-30

    Bacterial infections causing mastitis in sheep can result in severe economic losses for farmers. A large survey of milk samples from ewes with mastitis in Sardinia, Italy, indicated an increasing prevalence of Pseudomonas aeruginosa infections. It has been shown previously that during chronic, biofilm-associated infections P. aeruginosa populations diversify. We report the phenotypic and genomic characterisation of two clonal P. aeruginosa isolates (PSE305 and PSE306) from a mastitis infection outbreak, representing distinct colony morphology variants. In addition to pigment production, PSE305 and PSE306 differed in phenotypic characteristics including biofilm formation, utilisation of various carbon and nitrogen sources, twitching motility. We found higher levels of expression of genes associated with biofilm formation (pelB) and twitching motility (flgD) in PSE305, compared to the biofilm and twitching-defective PSE306. Comparative genomics analysis revealed single nucleotide polymorphisms (SNPs) and minor insertion/deletion variations between PSE305 and PSE306, including a SNP mutation in the pilP gene of PSE306. By introducing a wild-type pilP gene we were able to partially complement the defective twitching motility of PSE306. There were also three larger regions of difference between the two genomes, indicating genomic instability. Hence, we have demonstrated that P. aeruginosa population divergence can occur during an outbreak of mastitis, leading to significant variations in phenotype and genotype, and resembling the behaviour of P. aeruginosa during chronic biofilm-associated infections.

  20. Antimicrobial potentials of Helicteres isora silver nanoparticles against extensively drug-resistant (XDR) clinical isolates of Pseudomonas aeruginosa.

    PubMed

    Mapara, Nikunj; Sharma, Mansi; Shriram, Varsha; Bharadwaj, Renu; Mohite, K C; Kumar, Vinay

    2015-12-01

    Pseudomonas aeruginosa is a leading opportunistic pathogen and its expanding drug resistance is a growing menace to public health. Its ubiquitous nature and multiple resistance mechanisms make it a difficult target for antimicrobial chemotherapy and require a fresh approach for developing new antimicrobial agents against it. The broad-spectrum antibacterial effects of silver nanoparticles (SNPs) make them an excellent candidate for use in the medical field. However, attempts made to check their potency against extensively drug-resistant (XDR) microbes are meager. This study describes the biosynthesis and biostabilization of SNPs by Helicteres isora aqueous fruit extract and their characterization by ultraviolet-visible spectroscopy, transmission electron microscopy, dynamic light scattering, X-ray diffraction, and Fourier transform infrared spectroscopy. Majority of SNPs synthesized were of 8--20-nm size. SNPs exhibited dose-dependent antibacterial activities against four XDR P. aeruginosa (XDR-PA) clinical isolates as revealed by growth curves, with a minimum inhibitory concentration of 300 μg/ml. The SNPs exhibited antimicrobial activity against all strains, with maximum zone of inhibition (16.4 mm) in XRD-PA-2 at 1000 μg/ml. Amongst four strains, their susceptibilities to SNPs were in the following order: XDR-PA-2 > XDR-PA-4 > XDR-PA-3 > XDR-PA-1. The exposure of bacterial cells to 300 μg/ml SNPs resulted into a substantial leakage of reducing sugars and proteins, inactivation of respiratory chain dehydrogenases, and eventual cell death. SNPs also induced lipid peroxidation, a possible underlying factor to membrane porosity. The effects were more pronounced in XDR-PA-2 which may be correlated with its higher susceptibility to SNPs. These results are indicative of SNP-induced turbulence of membranous permeability as an important causal factor in XDR-PA growth inhibition and death.

  1. Genetic variability associated with photosynthetic pigment concentration, and photochemical and nonphotochemical quenching, in strains of the cyanobacterium Microcystis aeruginosa.

    PubMed

    Bañares-España, Elena; López-Rodas, Victoria; Costas, Eduardo; Salgado, Concepción; Flores-Moya, Antonio

    2007-06-01

    Although populations of cyanobacteria are usually considered to be clonal, their capacity to survive environmental changes suggests intrapopulation genetic variation. We therefore estimated the genetic variability on the basis of two processes important for any photoautotroph - photochemical and nonphotochemical quenching - as well as photosynthetic pigment concentrations. For this purpose, two parameters related to photochemical and nonphotochemical quenching were measured using specific experimental and statistical procedures, in 25 strains of the cyanobacterium Microcystis aeruginosa, along with their contents of chlorophyll a, total carotenoids and phycocyanin. The experimental procedure allowed discrimination between genetic and nongenetic (or residual) variability among strains. The high genetic variability found in photosynthetic pigments and both photosynthetic parameters denotes large differences even among strains isolated from the same community. The high genetic diversity within a population could be important for the evolutionary success of cyanobacteria.

  2. Carbenicillin resistance of Pseudomonas aeruginosa.

    PubMed Central

    Rodríguez-Tebar, A; Rojo, F; Dámaso, D; Vázquez, D

    1982-01-01

    Four strains of Pseudomonas aeruginosa obtained from clinical isolates which are carbenicillin resistant were studied to find the cause(s) of resistance to this beta-lactam antibiotic. The electrophoresis patterns of the four strains (PH20610, PH20815, PH4011, and PH4301) were found to be different from those of a wild-type strain, P. aeruginosa NCTC 10662, and appeared to lack penicillin-binding protein 2. Affinity of other penicillin-binding proteins from strains PH20610 and PH20815 for carbenicillin seemed to be normal or slightly diminished. Electrophoretic patterns of penicillin-binding proteins from strains PH4011 and PH4301 had more profound differences, since the affinities of their penicillin-binding proteins 1a, 1b, and 4 for carbenicillin were decreased by nearly two orders of magnitude relative to the preparations from the wild-type strain. Kinetic studies on binding of carbenicillin to penicillin-binding proteins both in isolated membrane preparations and in intact cells revealed that carbenicillin penetration into resistant cells was a much slower process than in susceptible cells, suggesting that the outer envelope structures serve as an efficient barrier against carbenicillin entry into our P. aeruginosa strains from clinical isolates. PMID:6821456

  3. Antimicrobial activity of biogenically produced spherical Se-nanomaterials embedded in organic material against Pseudomonas aeruginosa and Staphylococcus aureus strains on hydroxyapatite-coated surfaces.

    PubMed

    Piacenza, Elena; Presentato, Alessandro; Zonaro, Emanuele; Lemire, Joseph A; Demeter, Marc; Vallini, Giovanni; Turner, Raymond J; Lampis, Silvia

    2017-02-23

    In an effort to prevent the formation of pathogenic biofilms on hydroxyapatite (HA)-based clinical devices and surfaces, we present a study evaluating the antimicrobial efficacy of Spherical biogenic Se-Nanostructures Embedded in Organic material (Bio Se-NEMO-S) produced by Bacillus mycoides SelTE01 in comparison with two different chemical selenium nanoparticle (SeNP) classes. These nanomaterials have been studied as potential antimicrobials for eradication of established HA-grown biofilms, for preventing biofilm formation on HA-coated surfaces and for inhibition of planktonic cell growth of Pseudomonas aeruginosa NCTC 12934 and Staphylococcus aureus ATCC 25923. Bio Se-NEMO resulted more efficacious than those chemically produced in all tested scenarios. Bio Se-NEMO produced by B. mycoides SelTE01 after 6 or 24 h of Na2 SeO3 exposure show the same effective antibiofilm activity towards both P. aeruginosa and S. aureus strains at 0.078 mg ml(-1) (Bio Se-NEMO6 ) and 0.3125 mg ml(-1) (Bio Se-NEMO24 ). Meanwhile, chemically synthesized SeNPs at the highest tested concentration (2.5 mg ml(-1) ) have moderate antimicrobial activity. The confocal laser scanning micrographs demonstrate that the majority of the P. aeruginosa and S. aureus cells exposed to biogenic SeNPs within the biofilm are killed or eradicated. Bio Se-NEMO therefore displayed good antimicrobial activity towards HA-grown biofilms and planktonic cells, becoming possible candidates as new antimicrobials.

  4. [Shall we report the carbapenem resistance in Pseudomonas aeruginosa and Acinetobacter baumannii strains detected by BD Phoenix system?].

    PubMed

    Oğünç, Dilara; Ongüt, Gözde; Ozen, Nevgün Sepin; Baysan, Betil Ozhak; Günseren, Filiz; Dağlar, Duygu; Demirbakan, Hadiye; Gültekin, Meral

    2010-04-01

    Imipenem and meropenem are broad spectrum antimicrobial agents that are especially useful in the treatment of nosocomially acquired Pseudomonas aeruginosa and Acinetobacter spp. infections. Previous reports have noted that susceptibility tests could show false resistance to imipenem. For this reason, Centers for Disease Control and Prevention has recommended that all carbapenem resistant or intermediate resistant isolates should be tested with an additional method to verify the results. This study was aimed to evaluate the imipenem and meropenem susceptibilities by disk diffusion, E-test and broth microdilution in P. aeruginosa and Acinetobacter baumannii strains found to be resistant or intermediate to imipenem-meropenem by BD Phoenix automated susceptibility testing system. Between January 2006-January 2007, 85 non-duplicate isolates of A. baumannii and 51 non-duplicate isolates of P. aeruginosa which were determined as resistant or intermediate resistant to imipenem and/or meropenem by BD Phoenix automated identification and susceptibility system (Becton Dickinson, Sparks, MD, USA) were collected in Akdeniz University Hospital Central Laboratory. All strains were tested by E-test (AB Biodisk, Sweden), disk diffusion and reference broth microdilution (BMD) method following CLSI recommendations. All 51 isolates of P. aeruginosa determined as imipenem and/or meropenem resistant or intermediate resistant by BD Phoenix, were found to be imipenem and/or meropenem resistant or intermediate resistant by the reference BMD method. Minor error rates were same for all testing systems (1.9%) except for the meropenem results of BD Phoenix system (5.9%). No major errors were produced by any system. For A. baumannii, only one very major error was detected for meropenem by BD Phoenix system. Number of minor errors determined for meropenem by all testing systems compared to the reference test, ranged from 2 (2.4%) to 3 (3.5%). It was concluded that carbapenem susceptibility test

  5. Crataeva nurvala nanoparticles inhibit virulence factors and biofilm formation in clinical isolates of Pseudomonas aeruginosa.

    PubMed

    Ali, Syed Ghazanfar; Ansari, Mohammad Azam; Khan, Haris M; Jalal, Mohammad; Mahdi, Abbas Ali; Cameotra, Swaranjit Singh

    2017-03-01

    Green synthesized nanoparticles have gained great attention due to their non-toxic and non-hazardous nature. In the present study, bark extract of the medicinal plant in Ayurveda Crataeva nurvala (Buch-Ham) (CN) was chosen for the biosynthesis of silver nanoparticles (AgNPs). These NPs were characterized by Ultra violet visible spectroscopy, Fourier Transform Infra Red, Atomic Force Microscopy, and Transmission Electron Microscopy (TEM). The average particle size of green synthesized CN-AgNPs was 15.2 ± 1.01 nm. Gas chromatography- mass spectrometry analysis of methanolic bark extract involved in the formation of CN-AgNPs revealed lupeol as a major active component. In this study, CN-AgNPs (15 μg ml(-1) ) efficiently suppressed the production of quorum sensing mediated virulence factors viz. pyocyanin, protease, hemolysin, and biofilm formation in Pseudomonas aeruginosa. The pyocyanin production was strongly inhibited (74.64%) followed by proteolysis (47.3%) and hemolysin production (47.7%). However, the biofilm forming ability was maximally reduced up to 79.70%. Moreover, the Confocal Laser Scanning Microscopic Analysis showed that CN-AgNPs inhibit colonization of P. aeruginosa on to the surface. Furthermore, TEM analysis revealed internalization of CN-AgNPs inside the bacterial cell. It is concluded that green synthesized AgNPs have great potential to inhibit virulence factors and biofilm forming ability of drug-resistant clinical isolates of P. aeruginosa.

  6. Modulation of behaviour and virulence of a high alginate expressing Pseudomonas aeruginosa strain from cystic fibrosis by oral commensal bacterium Streptococcus anginosus

    PubMed Central

    Qureshi, Muhammad R.

    2017-01-01

    Cystic fibrosis (CF) airways harbour complex and dynamic polymicrobial communities that include many oral bacteria. Despite increased knowledge of CF airway microbiomes the interaction between established CF pathogens and other resident microbes and resulting impact on disease progression is poorly understood. Previous studies have demonstrated that oral commensal streptococci of the Anginosus group (AGS) can establish chronic pulmonary infections and become numerically dominant in CF sputa indicating that they play an important role in CF microbiome dynamics. In this study a strain of Pseudomonas aeruginosa (DWW2) of the mucoid alginate overproducing phenotype associated with chronic CF airway infection and a strain of the oral commensal AGS species Streptococcus anginosus (3a) from CF sputum were investigated for their ability to co-exist and their responses to biofilm co-culture. Bacteria in biofilms were quantified, pyocyanin expression by DWW2 was measured and the effect of AGS strain 3a on reversion of DWW2 to a non-mucoidal phenotype investigated. The virulence of DWW2, 3a and colony variant phenotypes of DWW2 in mono- and co-culture were compared in a Galleria mellonella infection model. Co-culture biofilms were formed in normoxic, hypercapnic (10% CO2) and anoxic atmospheres with the streptococcus increasing in number in co-culture, indicating that these bacteria would be able to co-exist and thrive within the heterogeneous microenvironments of the CF airway. The streptococcus caused increased pyocyanin expression by DWW2 and colony variants by stimulating reversion of the mucoid phenotype to the high pyocyanin expressing non-mucoid phenotype. The latter was highly virulent in the infection model with greater virulence when in co-culture with the streptococcus. The results of this study demonstrate that the oral commensal S. anginosus benefits from interaction with P. aeruginosa of the CF associated mucoid phenotype and modulates the behaviour of the

  7. Preparation, characterization and in vitro antimicrobial activity of liposomal ceftazidime and cefepime against Pseudomonas aeruginosa strains

    PubMed Central

    Torres, Ieda Maria Sapateiro; Bento, Etiene Barbosa; Almeida, Larissa da Cunha; de Sá, Luisa Zaiden Carvalho Martins; Lima, Eliana Martins

    2012-01-01

    Pseudomonas aeruginosa is an opportunistic microorganism with the ability to respond to a wide variety of environmental changes, exhibiting a high intrinsic resistance to a number of antimicrobial agents. This low susceptibility to antimicrobial substances is primarily due to the low permeability of its outer membrane, efflux mechanisms and the synthesis of enzymes that promote the degradation of these drugs. Cephalosporins, particularty ceftazidime and cefepime are effective against P. aeruginosa, however, its increasing resistance has limited the usage of these antibiotics. Encapsulating antimicrobial drugs into unilamellar liposomes is an approach that has been investigated in order to overcome microorganism resistance. In this study, antimicrobial activity of liposomal ceftazidime and cefepime against P. aeruginosa ATCC 27853 and P. aeruginosa SPM-1 was compared to that of the free drugs. Liposomal characterization included diameter, encapsulation efficiency and stability. Minimum Inhibitory Concentration (MIC) was determined for free and liposomal forms of both drugs. Minimum Bactericidal Concentration (MBC) was determined at concentrations 1, 2 and 4 times MIC. Average diameter of liposomes was 131.88 nm and encapsulation efficiency for cefepime and ceftazidime were 2.29% end 5.77%, respectively. Improved stability was obtained when liposome formulations were prepared with a 50% molar ratio for cholesterol in relation to the phospholipid. MIC for liposomal antibiotics for both drugs were 50% lower than that of the free drug, demonstrating that liposomal drug delivery systems may contribute to increase the antibacterial activity of these drugs. PMID:24031917

  8. 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

  9. Genetic diversity of clinical Pseudomonas aeruginosa isolates in a public hospital in Spain

    PubMed Central

    2013-01-01

    Background Pseudomonas aeruginosa is an important nosocomial pathogen that exhibits multiple resistances to antibiotics with increasing frequency, making patient treatment more difficult. The aim of the study is to ascertain the population structure of this clinical pathogen in the Hospital Son Llàtzer, Spain. Results A significant set (56) of randomly selected clinical P. aeruginosa isolates, including multidrug and non-multidrug resistant isolates, were assigned to sequence types (STs) and compared them with their antibiotic susceptibility profile classified as follows: extensively drug resistant (XDR), multidrug resistant (MDR) and non-multidrug resistant (non-MDR). The genetic diversity was assessed by applying the multilocus sequence typing (MLST) scheme developed by Curran and collaborators, and by the phylogenetic analysis of a concatenated tree. The analysis of seven loci, acsA, aroE, guaA, mutL, nuoD, ppsA and trpE, demonstrated that the prevalent STs were ST-175, ST-235 and ST-253. The majority of the XDR and MDR isolates were included in ST-175 and ST-235. ST-253 is the third in frequency and included non-MDR isolates. The 26 singleton sequence types corresponded mainly to non-MDR isolates. Twenty-two isolates corresponded to new sequence types (not previously defined) of which 12 isolates were non-MDR and 10 isolates were MDR or XDR. Conclusions The population structure of clinical P. aeruginosa present in our hospital indicates the coexistence of nonresistant and resistant isolates with the same sequence type. The multiresistant isolates studied are grouped in the prevalent sequence types found in other Spanish hospitals and at the international level, and the susceptible isolates correspond mainly to singleton sequence types. PMID:23773707

  10. Characterization of carbapenem resistance mechanisms and integrons in Pseudomonas aeruginosa strains from blood samples in a French hospital.

    PubMed

    Rojo-Bezares, Beatriz; Cavalié, Laurent; Dubois, Damien; Oswald, Eric; Torres, Carmen; Sáenz, Yolanda

    2016-04-01

    Metallo-β-lactamases (MBLs), porin OprD, integrons, virulence factors and the clonal relationships were characterized in imipenem-resistant Pseudomonas aeruginosa (IRPA) isolates. Fifty-six IRPA strains were recovered from blood samples of different patients at a Toulouse teaching hospital from 2011 to 2013. Susceptibility testing of 14 antibiotics was performed by the disc diffusion method. Detection and characterization of MBLs, the oprD gene and integrons were studied by PCR and sequencing. Thirteen genes involved in the virulence of P. aeruginosa were analysed. Molecular typing of IRPA strains was performed by PFGE and multilocus sequence typing. In this study, 61 % of the IRPA isolates showed a multi-resistance phenotype. The MBL phenotype, detected in three isolates (5.4 %), was linked to the blaVIM-2 gene. The oprD gene was amplified in 55 (98.2 %) IRPA strains, and variations were observed in 54 of them. Insertion sequences (IS) truncating oprD were detected in eight IRPA strains, with the novel ISPa56 identified in two strains. Class 1 integrons were detected in 24 (42.9 %) IRPA strains. The blaVIM-2 gene was found inside the class 1 integron arrangements. The new integrons In1054 (intI1-aacA56-qacEΔ1-sul1) and In1160 (intI1-aacA4-aacC1d-ISKpn4-gcuE-qacEΔ1-sul1) have been described for the first time, to the best of our knowledge, in this study. A high clonal diversity was found in our strains. Among the variety of sequence types (STs) found, ST175, ST233, ST235, ST244 and ST654 were noteworthy as epidemic clones. In conclusion, 5.4 % of IRPA strains showed an MBL phenotype linked to the blaVIM-2 gene. The identified oprD high polymorphism could be implicated in the variable resistance to carbapenems in IRPA strains. The dissemination of high-risk clones is a cause of concern.

  11. Genotypic characterization of Pseudomonas aeruginosa strains recovered from patients with cystic fibrosis after initial and subsequent colonization.

    PubMed

    Munck, A; Bonacorsi, S; Mariani-Kurkdjian, P; Lebourgeois, M; Gérardin, M; Brahimi, N; Navarro, J; Bingen, E

    2001-10-01

    Chronic infection by Pseudomonas aeruginosa (PA) in patients with cystic fibrosis (CF) is preceded by a period of colonization and acute infection. Early aggressive antibiotic treatment of initial colonisation may prevent or at least delay chronic pulmonary infection. We initiated treatment with a combination of IV beta-lactam tobramycin, followed by nebulized colistin when PA was first isolated from patients with CF. Subsequent serial PA isolates obtained from these colonized CF patients were characterized by means of molecular methods to determine whether they were genetically related to the initial strain. Initial colonization was eradicated in all 19 patients. All patients reacquired PA within 3-25 months during the 3 years of follow-up. Fourteen patients acquired a new PA strain with a distinct genotypic profile, suggesting a new source of contamination. Five patients had two PA isolates with identical genotypes, suggesting either previous undetected respiratory tract colonization or a persistent environmental source of contamination.

  12. Epinecidin-1 Has Immunomodulatory Effects, Facilitating Its Therapeutic Use in a Mouse Model of Pseudomonas aeruginosa Sepsis

    PubMed Central

    Pan, Chieh-Yu; Chen, Jian-Chyi; Sheen, Jenn-Feng; Lin, Tai-Lang

    2014-01-01

    Antimicrobial peptides (AMPs) are garnering attention as possible alternatives to antibiotics. Here, we describe the antimicrobial properties of epinecidin-1 against a multidrug-resistant clinical isolate of P. aeruginosa (P. aeruginosa R) and a P. aeruginosa strain from ATCC (P. aeruginosa ATCC 19660) in vivo. The MICs of epinecidin-1 against P. aeruginosa R and P. aeruginosa ATCC 19660 were determined and compared with those of imipenem. Epinecidin-1 was found to be highly effective at combating peritonitis infection caused by P. aeruginosa R or P. aeruginosa ATCC 19660 in mouse models, without inducing adverse behavioral effects or liver or kidney toxicity. Taken together, our results indicate that epinecidin-1 enhances the rate of survival of mice infected with the bacterial pathogen P. aeruginosa through both antimicrobial and immunomodulatory effects. PMID:24820078

  13. Novel Combinations of Synthesized ZnO NPs and Ceftazidime: Evaluation of their Activity against Standards and New Clinically Isolated Pseudomonas aeruginosa

    PubMed Central

    Isaei, Elham; Mansouri, Shahla; Mohammadi, Fereshteh; Taheritarigh, Sadegh; Mohammadi, Zohreh

    2016-01-01

    Background: Antibiotic resistant bacteria can be considered as a main problem in infection management. Zinc oxide nanoparticles (ZnO NPs), individually or in combination with antibiotics, can be considered as good candidates for struggling against drug resistant bacteria. Methods: In this study, Zinc oxide nanoparticles were synthesized using sol-gel method in low temperature as a cost effective procedure and characterized by X-ray diffraction and Scanning Electron Microscopy. Antibacterial activity of 9 new combinations of Zinc oxide nanoparticles and ceftazidime was assessed against standards and new clinically isolated multi drug resistant Pseudomonas aeruginosa (P. aeruginosa), in order to evaluate enhancement effect of synthesized Zinc oxide nanoparticles on antibacterial activity of ceftazidime. Results: The results indicated that desirable effects can be seen at 6 and 7 mM of Zinc oxide nanoparticles (60 to 100% inhibition). Moreover, after evaluation of 9 new combinations with various concentrations of both components, it was demonstrated that Zinc oxide nanoparticles can enhance the antibacterial activity of ceftazidime, against some bacterial strains of P. aeruginosa. The highest activity was observed with the concentration of 20 μg/ml ceftazidime in the presence of 5, 6 or 7 mM of Zinc oxide nanoparticles. Conclusion: Zinc oxide nanoparticles in appropriate concentrations can be proposed as new and promising candidates for overcoming bacterial resistance. PMID:27920884

  14. Art-175 is a highly efficient antibacterial against multidrug-resistant strains and persisters of Pseudomonas aeruginosa.

    PubMed

    Briers, Yves; Walmagh, Maarten; Grymonprez, Barbara; Biebl, Manfred; Pirnay, Jean-Paul; Defraine, Valerie; Michiels, Jan; Cenens, William; Aertsen, Abram; Miller, Stefan; Lavigne, Rob

    2014-07-01

    Artilysins constitute a novel class of efficient enzyme-based antibacterials. Specifically, they covalently combine a bacteriophage-encoded endolysin, which degrades the peptidoglycan, with a targeting peptide that transports the endolysin through the outer membrane of Gram-negative bacteria. Art-085, as well as Art-175, its optimized homolog with increased thermostability, are each composed of the sheep myeloid 29-amino acid (SMAP-29) peptide fused to the KZ144 endolysin. In contrast to KZ144, Art-085 and Art-175 pass the outer membrane and kill Pseudomonas aeruginosa, including multidrug-resistant strains, in a rapid and efficient (∼ 5 log units) manner. Time-lapse microscopy confirms that Art-175 punctures the peptidoglycan layer within 1 min, inducing a bulging membrane and complete lysis. Art-175 is highly refractory to resistance development by naturally occurring mutations. In addition, the resistance mechanisms against 21 therapeutically used antibiotics do not show cross-resistance to Art-175. Since Art-175 does not require an active metabolism for its activity, it has a superior bactericidal effect against P. aeruginosa persisters (up to >4 log units compared to that of the untreated controls). In summary, Art-175 is a novel antibacterial that is well suited for a broad range of applications in hygiene and veterinary and human medicine, with a unique potential to target persister-driven chronic infections.

  15. IDENTIFICATION OF MICROCYSTIN TOXINS FROM A STRAIN OF MICROCYSTIS AERUGINOSA BY LIQUID CHROMATOGRAPHY INTRODUCTION INTO A HYBRID LINEAR ION TRAP-FOURIER TRANSFORM ION CYCLOTRON RESONANCE MASS SPECTROMETER

    EPA Science Inventory

    The cyclic heptapeptide microcystin toxins produced by a strain of Microcystis aeruginosa that has not been investigated previously were separated by liquid chromatography and identified by high-accuracy m/z measurements of their [M + H]+ ions and the fragment i...

  16. Difficult-to-detect carbapenem-resistant IMP13-producing P. aeruginosa: experience feedback concerning a cluster of urinary tract infections at a surgical clinic in France

    PubMed Central

    2013-01-01

    Background We report a carbapenem-resistant P. aeruginosa clone responsible for a cluster of urinary tract infections in elderly surgery patients, diagnosed during a three-month period in a 59-bed surgical clinic. Findings The clonal nature of the cluster was established by molecular study of the P. aeruginosa isolates (PFGE and MLST). Despite an MIC of imipenem in the susceptibility range for two isolates, all were metallo-β-lactamase-producers (IMP13-type, clone ST621). We conducted a review of the medical and surgical procedures. We tested water delivered into the clinic and urological devices for the presence of the epidemic strain. The hygiene nurse observed hygiene practices. A week after the implementation of barrier precautions around the fourth infected patient, we studied the extent to which the patients hospitalised were colonised to assess whether the spread of the epidemic strain had been controlled. Conclusions 1/ Our findings indicate the difficulties in the detection of the metallo-β-lactamase in this clone, that resulted in the alert being delayed. 2/ Unlike most investigations of UTI outbreaks described in urology wards, we did not detect any contaminated urological devices or water colonisation. 3/ Consistent with outbreaks involving the IMP-13 clone in critical care units, the observation of inadequate application of standard precautions argued for patient-to-patient transmission during urinary management of the urology patients. 4/ The implementation of barrier precautions around infected patients resulted in control of the spread of the epidemic clone. This report serves as an alert concerning a difficult-to-detect multidrug-resistant P. aeruginosa clone in elderly urology patients. PMID:23557539

  17. Unusual non-fluorescent broad spectrum siderophore activity (SID EGYII) by Pseudomonas aeruginosa strain EGYII DSM 101801 and a new insight towards simple siderophore bioassay.

    PubMed

    Embaby, Amira M; Heshmat, Yasmin; Hussein, Ahmed

    2016-03-01

    Present study highlights an unusual non-fluorescent hydroxamate broad spectrum siderophore (SID EGYII) activity from Pseudomonas aeruginosa strain EGYII DSM 101801, a soil bacterial isolate, along with simple low cost effective siderophore bioassay. Detection of SID EGYII activity qualitatively was proved by masking this activity against Erwinia amylovora strain EGY1 DSM 101800, an indicator strain, in well-cut diffusion assay containing 100 µM FeCl3. SID EGYII activity was expressed quantitatively as arbitrary units [Siderophore arbitrary units (SAU)] 380 SAU/mL against E. amylovora strain EGY1 DSM 101800. Maximal SID EGYII activity was achieved upon growing P. aeruginosa strain EGYII DSM 101801 in PYB broth at 180 rpm for 24 h. SID EGYII displayed a broad spectrum antimicrobial activity against some human pathogens (i.e., Gram-positive bacteria, Gram-negative bacteria and yeasts) and a fireblight plant pathogen. Interestingly, transformants of Escherichia coli JM109 (DE3)pSID/EGYII harboring P. aeruginosa strain EGYII DSM 101801 plasmid demonstrated a perceivable antimicrobial activity against E. amylovora strain EGY1 DSM 101800. The broad spectrum antimicrobial activity of the unusual non-fluorescent SID EGYII would underpin its high potential in targeting bacterial pathogens posing probable threats to human health and agricultural economy. The present simple low cost effective bioassay is a new insight towards an alternative to the expensive cumbersome siderophore Chrome Azurol S assay.

  18. In Vitro Activity of Fosfomycin against a Collection of Clinical Pseudomonas aeruginosa Isolates from 16 Spanish Hospitals: Establishing the Validity of Standard Broth Microdilution as Susceptibility Testing Method

    PubMed Central

    Díez-Aguilar, María; del Campo, Rosa; García-Castillo, María; Zamora, Javier; Cantón, Rafael

    2013-01-01

    The broth microdilution method for fosfomycin and Pseudomonas aeruginosa was assessed and compared with the approved agar dilution method in 206 genetically unrelated P. aeruginosa clinical isolates. Essential agreement between the two methods was 84%, and categorical agreement was 89.3%. Additionally, Etest and disk diffusion assays were performed. Results validate broth microdilution as a reliable susceptibility testing method for fosfomycin against P. aeruginosa. Conversely, unacceptable concordance was established between Etest and disk diffusion results with agar dilution results. PMID:23939889

  19. [Molecular typification of Pseudomonas aeruginosa strains isolated from patients with cystic fibrosis].

    PubMed

    Iglesias, N G; Marengo, J M; Rentería, F; Gatti, B; Segal, E; Semorile, L

    2008-01-01

    Cystic fibrosis is the most frequent lethal genetic disease that affects the caucasian population. The main cause of morbidity is the chronic lung infection, being the infection caused by Pseudomonas aeruginosa the most difficult to eradicate. This bacteria can be acquired in direct form, by person-to-person transfer, or indirectly, by hospital acquired infection. The Centro Provincial de Referencia de Fibrosis Quistica functioning in the Hospital de Niños "Sor María Ludovica", in La Plata, cares almost 220 patients aged two months to 45 years. The life expectancy depends of factors like the early diagnosis of the disease and the later acquisition of the chronic lung infection. The purpose of this work was the molecular typing of P. aeruginosa isolates obtained from cystic fibrosis patients to evaluate the genomic relationship among them. The study was carried out using RAPD-PCR. The analysis showed a great genetic heterogeneity among the isolates. The separation of the patients in groups in accordance with its bacteriology, that implies the attendance in different days and the implementation of isolation (or segregation) measures had demonstrated to be, in addition to other strategies, effective in the reduction of cross infections.

  20. Sensitive and specific modified Hodge test for KPC and metallo-beta- lactamase detection in Pseudomonas aeruginosa by use of a novel indicator strain, Klebsiella pneumoniae ATCC 700603.

    PubMed

    Pasteran, Fernando; Veliz, Omar; Rapoport, Melina; Guerriero, Leonor; Corso, Alejandra

    2011-12-01

    We evaluated the ability of the modified Hodge test to discriminate between KPC- and metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa isolates and carbapenemase nonproducers. With Escherichia coli ATCC 25922 as the indicator strain, the MHT resulted in low sensitivity, specificity, and repeatability. Replacing the indicator strain with Klebsiella pneumoniae ATCC 700603 led to an improved performance (100%, 97%, 0%, and 100% sensitivity, specificity, indeterminate results and repeatability, respectively).

  1. Pseudomonas aeruginosa strain WI-1 from Mandovi estuary possesses metallothionein to alleviate lead toxicity and promotes plant growth.

    PubMed

    Naik, Milind Mohan; Pandey, Anju; Dubey, Santosh Kumar

    2012-05-01

    A bacterial isolate from Mandovi estuary Goa, India, which can resist 0.6mM lead nitrate in Tris-buffered minimal medium was identified as Pseudomonas aeruginosa and designated as strain WI-1. PCR amplification clearly revealed presence of bmtA gene encoding bacterial metallothionein responsible for metal sequestration and AAS analysis proved intracellular bioaccumulation of 26.5mg lead/gram dry weight of cells. SDS-PAGE analysis confirmed lead induced bacterial metallothionein with molecular weight 11 kDa, which corresponds to the predicted bmtA gene. Significant growth inhibition of phytopathogenic fungi Fusarium oxysporum NCIM 1008 by siderophore-rich culture supernatant was also observed. Pot experiment with Pisum sativum L inoculated with this strain revealed higher seed germination percentage and significant growth promotion than uninoculated seeds in a soil amended with 7.704 g/kg lead, which indicates amelioration of lead toxicity. This lead resistant strain showed cross tolerance to cadmium, mercury and Tributyltin chloride (TBTC) along with resistance to multiple antibiotics.

  2. Isolation of Pseudomonas aeruginosa strains from dental office environments and units in Barretos, state of São Paulo, Brazil, and analysis of their susceptibility to antimicrobial drugs

    PubMed Central

    de Oliveira, Ana Claudia; Maluta, Renato Pariz; Stella, Ariel Eurides; Rigobelo, Everlon Cid; Marin, José Moacir; de Ávila, Fernando Antonio

    2008-01-01

    A wide variety of opportunistic pathogens has been detected in the tubing supplying water to odontological equipment, in special in the biofilm lining of these tubes. Among these pathogens, Pseudomonas aeruginosa, one of the leading causes of nosocomial infections, is frequently found in water lines supplying dental units. In the present work, 160 samples of water, and 200 fomite samples from forty dental units were collected in the city of Barretos, State of São Paulo, Brazil and evaluated between January and July, 2005. Seventy-six P. aeruginosa strains, isolated from the dental environment (5 strains) and water system (71 strains), were tested for susceptibility to six antimicrobial drugs most frequently used against P. aeruginosa infections. Susceptibility to ciprofloxacin, followed by meropenem was the predominant profile. The need for effective means of reducing the microbial burden within dental unit water lines is emphasized, and the risk of exposure and cross-infection in dental practice, in special when caused by opportunistic pathogens like P. aeruginosa, are highlighted. PMID:24031269

  3. Synthetic Peptide Vaccine Development: Designing Dual Epitopes into a Single Pilin Peptide Immunogen Generates Antibody Cross-reactivity between Two Strains of Pseudomonas aeruginosa

    PubMed Central

    Hackbarth, Clifton; Hodges, Robert S.

    2010-01-01

    One of the main challenges of Pseudomonas aeruginosa (P. aeruginosa) vaccine development is the design of an antigen that elicits cross-reactive antibodies against multiple virulent strains. Using a rational design approach, we have developed a single 17-residue peptide immunogen that generates antibodies that target the receptor binding domain (RBD) of the type IV pilus of more than one strain of P. aeruginosa. Using the RBD sequence, of native strain PAO as a template, we have systematically changed up to five residues in the PAO sequence of the peptide immunogen, into that of the PAK sequence. We show by indirect and competitive ELISA, that the mutant peptide immunogens elicit the development of polyclonal sera that is cross-reactive to both native strain PAO and PAK pilin. We further show that there are at least two separate antibody populations in the polyclonal sera that possess closely-related epitopes but which are each strain specific. Moreover, part of the epitope for the PAO specific antibodies consists of several residues outside the disulfide loop of the receptor binding domain. This allows us to create two unique epitopes within the same receptor binding domain sequence. PMID:20807222

  4. A Geobacter sulfurreducens strain expressing pseudomonas aeruginosa type IV pili localizes OmcS on pili but is deficient in Fe(III) oxide reduction and current production.

    PubMed

    Liu, Xing; Tremblay, Pier-Luc; Malvankar, Nikhil S; Nevin, Kelly P; Lovley, Derek R; Vargas, Madeline

    2014-02-01

    The conductive pili of Geobacter species play an important role in electron transfer to Fe(III) oxides, in long-range electron transport through current-producing biofilms, and in direct interspecies electron transfer. Although multiple lines of evidence have indicated that the pili of Geobacter sulfurreducens have a metal-like conductivity, independent of the presence of c-type cytochromes, this claim is still controversial. In order to further investigate this phenomenon, a strain of G. sulfurreducens, designated strain PA, was constructed in which the gene for the native PilA, the structural pilin protein, was replaced with the PilA gene of Pseudomonas aeruginosa PAO1. Strain PA expressed and properly assembled P. aeruginosa PilA subunits into pili and exhibited a profile of outer surface c-type cytochromes similar to that of a control strain expressing the G. sulfurreducens PilA. Surprisingly, the strain PA pili were decorated with the c-type cytochrome OmcS in a manner similar to the control strain. However, the strain PA pili were 14-fold less conductive than the pili of the control strain, and strain PA was severely impaired in Fe(III) oxide reduction and current production. These results demonstrate that the presence of OmcS on pili is not sufficient to confer conductivity to pili and suggest that there are unique structural features of the G. sulfurreducens PilA that are necessary for conductivity.

  5. A Geobacter sulfurreducens Strain Expressing Pseudomonas aeruginosa Type IV Pili Localizes OmcS on Pili but Is Deficient in Fe(III) Oxide Reduction and Current Production

    PubMed Central

    Liu, Xing; Tremblay, Pier-Luc; Malvankar, Nikhil S.; Nevin, Kelly P.; Vargas, Madeline

    2014-01-01

    The conductive pili of Geobacter species play an important role in electron transfer to Fe(III) oxides, in long-range electron transport through current-producing biofilms, and in direct interspecies electron transfer. Although multiple lines of evidence have indicated that the pili of Geobacter sulfurreducens have a metal-like conductivity, independent of the presence of c-type cytochromes, this claim is still controversial. In order to further investigate this phenomenon, a strain of G. sulfurreducens, designated strain PA, was constructed in which the gene for the native PilA, the structural pilin protein, was replaced with the PilA gene of Pseudomonas aeruginosa PAO1. Strain PA expressed and properly assembled P. aeruginosa PilA subunits into pili and exhibited a profile of outer surface c-type cytochromes similar to that of a control strain expressing the G. sulfurreducens PilA. Surprisingly, the strain PA pili were decorated with the c-type cytochrome OmcS in a manner similar to the control strain. However, the strain PA pili were 14-fold less conductive than the pili of the control strain, and strain PA was severely impaired in Fe(III) oxide reduction and current production. These results demonstrate that the presence of OmcS on pili is not sufficient to confer conductivity to pili and suggest that there are unique structural features of the G. sulfurreducens PilA that are necessary for conductivity. PMID:24296506

  6. Within-host whole genome analysis of an antibiotic resistant Pseudomonas aeruginosa strain sub-type in cystic fibrosis

    PubMed Central

    Wee, Bryan A.; Ramsay, Kay A.; Kidd, Timothy J.; Ben Zakour, Nouri L.; Whiley, David M.; Beatson, Scott A.; Bell, Scott C.

    2017-01-01

    A Pseudomonas aeruginosa AUST-02 strain sub-type (M3L7) has been identified in Australia, infects the lungs of some people with cystic fibrosis and is associated with antibiotic resistance. Multiple clonal lineages may emerge during treatment with mutations in chromosomally encoded antibiotic resistance genes commonly observed. Here we describe the within-host diversity and antibiotic resistance of M3L7 during and after antibiotic treatment of an acute pulmonary exacerbation using whole genome sequencing and show both variation and shared mutations in important genes. Eleven isolates from an M3L7 population (n = 134) isolated over 3 months from an individual with cystic fibrosis underwent whole genome sequencing. A phylogeny based on core genome SNPs identified three distinct phylogenetic groups comprising two groups with higher rates of mutation (hypermutators) and one non-hypermutator group. Genomes were screened for acquired antibiotic resistance genes with the result suggesting that M3L7 resistance is principally driven by chromosomal mutations as no acquired mechanisms were detected. Small genetic variations, shared by all 11 isolates, were found in 49 genes associated with antibiotic resistance including frame-shift mutations (mexA, mexT), premature stop codons (oprD, mexB) and mutations in quinolone-resistance determining regions (gyrA, parE). However, whole genome sequencing also revealed mutations in 21 genes that were acquired following divergence of groups, which may also impact the activity of antibiotics and multi-drug efflux pumps. Comparison of mutations with minimum inhibitory concentrations of anti-pseudomonal antibiotics could not easily explain all resistance profiles observed. These data further demonstrate the complexity of chronic and antibiotic resistant P. aeruginosa infection where a multitude of co-existing genotypically diverse sub-lineages might co-exist during and after intravenous antibiotic treatment. PMID:28273168

  7. Within-host whole genome analysis of an antibiotic resistant Pseudomonas aeruginosa strain sub-type in cystic fibrosis.

    PubMed

    Sherrard, Laura J; Tai, Anna S; Wee, Bryan A; Ramsay, Kay A; Kidd, Timothy J; Ben Zakour, Nouri L; Whiley, David M; Beatson, Scott A; Bell, Scott C

    2017-01-01

    A Pseudomonas aeruginosa AUST-02 strain sub-type (M3L7) has been identified in Australia, infects the lungs of some people with cystic fibrosis and is associated with antibiotic resistance. Multiple clonal lineages may emerge during treatment with mutations in chromosomally encoded antibiotic resistance genes commonly observed. Here we describe the within-host diversity and antibiotic resistance of M3L7 during and after antibiotic treatment of an acute pulmonary exacerbation using whole genome sequencing and show both variation and shared mutations in important genes. Eleven isolates from an M3L7 population (n = 134) isolated over 3 months from an individual with cystic fibrosis underwent whole genome sequencing. A phylogeny based on core genome SNPs identified three distinct phylogenetic groups comprising two groups with higher rates of mutation (hypermutators) and one non-hypermutator group. Genomes were screened for acquired antibiotic resistance genes with the result suggesting that M3L7 resistance is principally driven by chromosomal mutations as no acquired mechanisms were detected. Small genetic variations, shared by all 11 isolates, were found in 49 genes associated with antibiotic resistance including frame-shift mutations (mexA, mexT), premature stop codons (oprD, mexB) and mutations in quinolone-resistance determining regions (gyrA, parE). However, whole genome sequencing also revealed mutations in 21 genes that were acquired following divergence of groups, which may also impact the activity of antibiotics and multi-drug efflux pumps. Comparison of mutations with minimum inhibitory concentrations of anti-pseudomonal antibiotics could not easily explain all resistance profiles observed. These data further demonstrate the complexity of chronic and antibiotic resistant P. aeruginosa infection where a multitude of co-existing genotypically diverse sub-lineages might co-exist during and after intravenous antibiotic treatment.

  8. Pseudomonas aeruginosa strain MA01 aerobically metabolizes the aminodinitrotoluenes produced by 2,4,6-trinitrotoluene nitro group reduction.

    PubMed

    Alvarez, M A; Kitts, C L; Botsford, J L; Unkefer, P J

    1995-11-01

    Many microbes reduce the nitro substituents of 2,4,6-trinitrotoluene (TNT), producing aminodinitrotoluenes (ADNTs). These compounds are recalcitrant to further breakdown and are acutely toxic. In a search for organisms capable of metabolizing ADNTs, a bacterial strain was isolated for the ability to use 2-aminobenzoate (anthranilate) as sole C-source. This isolate, Pseudomonas aeruginosa MA01, metabolized TNT by first reducing one nitro group to form either 2-amino-4,6-dinitrotoluene (2ADNT) or 4-amino-2,6-dinitrotoluene (4ADNT). However, strain MA01 was distinct from other TNT-reducing organisms in that it transformed these compounds into highly polar metabolites through an O2-dependent process. Strain MA01 was able to cometabolize TNT, 2ADNT, and 4ADNT in the presence of a variety of carbon and energy sources. During aerobic cometabolism with succinate, 45% of uniformly ring-labeled [14C]TNT was transformed to highly polar compounds. Aerobic cometabolism of purified [14C]2ADNT and [14C]4ADNT with succinate as C-source produced similar amounts of these polar metabolites. During O2-limited cometabolism with succinate as C-source and nitrate as electron acceptor, less than 8% of the [14C]TNT was transformed to polar metabolites. Purified 2,6-diamino-4-nitrotoluene was not metabolized, and while 2,4-diamino-6-nitrotoluene was acetylated, the product (N-acetyl-2,4-diamino-6-nitrotoluene) was not further metabolized. Therefore, strain MA01 metabolized TNT by oxidation of the ADNTs and not by reduction the remaining nitro groups on the ADNTs.

  9. Antibacterial compound produced by Pseudomonas aeruginosa strain UICC B-40, an endophytic bacterium isolated from Neesia altissima.

    PubMed

    Pratiwi, Rina Hidayati; Hidayat, Iman; Hanafi, Muhammad; Mangunwardoyo, Wibowo

    2017-04-01

    This study's aim was to determine the identity of antibacterial compounds produced by Pseudomonas aeruginosa strain UICC B-40 and describe the antibacterial compounds' mechanisms of action for damaging pathogenic bacteria cells. Isolation and identification of the compounds were carried out using thin layer chromatography (TLC), nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography mass spectrometry (LC-MS) analyses. Antibacterial activity was assayed via minimum inhibitory concentration (MIC) and the antibacterial compound mechanism was observed morphologically through scanning electron microscopy (SEM). This study successfully identified the (2E,5E)-phenyltetradeca-2,5-dienoate antibacterial compound (molecular weight 300 g/mol), composed of a phenolic ester, fatty acid and long chain of aliphatic group structures. MIC values for this compound were determined at 62.5 μg/ml against Staphylococcus aureus strain ATCC 25923. The mechanism of the compound involved breaking down the bacterial cell walls through the lysis process. The (2E,5E)-phenyltetradeca-2,5-dienoate compound exhibited inhibitory activity on the growth of Gram-positive bacteria.

  10. Conjugal transfer of R68.45 and FP5 between Pseudomonas aeruginosa strains in a freshwater environment.

    PubMed Central

    O'Morchoe, S B; Ogunseitan, O; Sayler, G S; Miller, R V

    1988-01-01

    Recent concern over the release of genetically engineered organisms has resulted in a need for information about the potential for gene transfer in the environment. In this study, the conjugal transfer in Pseudomonas aeruginosa of the plasmids R68.45 and FP5 was demonstrated in the freshwater environment of Fort Loudoun Resevoir, Knoxville, Tenn. When genetically well defined plasmid donor and recipient strains were introduced into test chambers suspended in Fort Loudoun Lake, transfer of both plasmids was observed. Conjugation occurred in both the presence and absence of the natural microbial community. The number of transconjugants recovered was lower when the natural community was present. Transfer of the broad-host-range plasmid R68.45 to organisms other than the introduced recipient was not observed in these chambers but was observed in laboratory simulations when an organism isolated from lakewater was used as the recipient strain. Although the plasmids transferred in laboratory studies were genetically and physically stable, a significant number of transconjugants recovered from the field trials contained deletions and other genetic rearrangements, suggesting that factors which increase gene instability are operating in the environment. The potential for conjugal transfer of genetic material must be considered in evaluating the release of any genetically engineered microorganism into a freshwater environment. Images PMID:3140724

  11. Effects of culture conditions of Pseudomonas aeruginosa strain RB on the synthesis of CdSe nanoparticles.

    PubMed

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

    2015-04-01

    Cadmium selenide (CdSe) was synthesized by Pseudomonas aeruginosa strain RB in a culture containing lactic acid as a carbon source, 1 mM selenite, and 1 mM cadmium under various conditions. High purity (1.02-1.16 of the atomic ratio of Se to Cd) and efficient synthesis of biogenic CdSe nanoparticles were observed at 25-30°C, 0.05-10 g L(-1) NaCl, and neutral pH conditions compared with other tested conditions. However, the size and shape of synthesized CdSe nanoparticles were not changed by changing culture conditions. The contents of S and Se in the particles respectively increased under alkaline and weak acidic conditions. Furthermore, high temperature (>37°C), high salinity (>10 g L(-1) NaCl), and alkaline pH affected the CdSe-synthesizing rate by strain RB. This report is the first optimizing the culture conditions for synthesizing biogenic CdSe nanoparticles in a batch processing.

  12. Environmental Pseudomonads Inhibit Cystic Fibrosis Patient-Derived Pseudomonas aeruginosa

    PubMed Central

    Chatterjee, Payel; Davis, Elizabeth; Yu, Fengan; James, Sarah; Wildschutte, Julia H.; Wiegmann, Daniel D.; Sherman, David H.; McKay, Robert M.; LiPuma, John J.

    2016-01-01

    ABSTRACT Pseudomonas aeruginosa is an opportunistic pathogen which is evolving resistance to many currently used antibiotics. While much research has been devoted to the roles of pathogenic P. aeruginosa in cystic fibrosis (CF) patients, less is known of its ecological properties. P. aeruginosa dominates the lungs during chronic infection in CF patients, yet its abundance in some environments is less than that of other diverse groups of pseudomonads. Here, we sought to determine if clinical isolates of P. aeruginosa are vulnerable to environmental pseudomonads that dominate soil and water habitats in one-to-one competitions which may provide a source of inhibitory factors. We isolated a total of 330 pseudomonads from diverse habitats of soil and freshwater ecosystems and competed these strains against one another to determine their capacity for antagonistic activity. Over 900 individual inhibitory events were observed. Extending the analysis to P. aeruginosa isolates revealed that clinical isolates, including ones with increased alginate production, were susceptible to competition by multiple environmental strains. We performed transposon mutagenesis on one isolate and identified an ∼14.8-kb locus involved in antagonistic activity. Only two other environmental isolates were observed to carry the locus, suggesting the presence of additional unique compounds or interactions among other isolates involved in outcompeting P. aeruginosa. This collection of strains represents a source of compounds that are active against multiple pathogenic strains. With the evolution of resistance of P. aeruginosa to currently used antibiotics, these environmental strains provide opportunities for novel compound discovery against drug-resistant clinical strains. IMPORTANCE We demonstrate that clinical CF-derived isolates of P. aeruginosa are susceptible to competition in the presence of environmental pseudomonads. We observed that many diverse environmental strains exhibited varied

  13. Surface-active potential of biosurfactants produced in curd whey by Pseudomonas aeruginosa strain-PP2 and Kocuria turfanesis strain-J at extreme environmental conditions.

    PubMed

    Dubey, Kirti V; Charde, Pravin N; Meshram, Sudhir U; Shendre, Latika P; Dubey, Vijay S; Juwarkar, Asha A

    2012-12-01

    Surface-active potential of biosurfactants produced cost-effectively in curd whey by Pseudomonas aeruginosa strain-PP2 and Kocuria turfanesis strain-J were tested using parameters viz. surface tension (ST) reduction, F(CMC) (highest dilution factor to reach critical micelle concentration) and emulsification index (EI-24) of pesticides; monocrotophos and imidacloprid at extreme environmental conditions. Results have shown that ST reduction of biosurfactants was stable at pH 2-11. High F(CMC) of the biosurfactant in the fermented whey at low pH improved emulsification of pesticides. ST marginally increased at 5% and 15% NaCl, resulting in high EI-24 and F(CMC). Over a range of temperatures 30-121 °C, ST remained low with a higher F(CMC) and EI-24 at 60 °C than at 121 and 30 °C. The biosurfactants have shown differences in their surface-active property and have marked specificity to emulsify pesticides in extreme environmental conditions.

  14. Pseudomonas aeruginosa infection in patients with cystic fibrosis: scientific evidence regarding clinical impact, diagnosis, and treatment*

    PubMed Central

    da Silva, Luiz Vicente Ribeiro Ferreira; Ferreira, Flavia de Aguiar; Reis, Francisco José Caldeira; de Britto, Murilo Carlos Amorim; Levy, Carlos Emilio; Clark, Otavio; Ribeiro, José Dirceu

    2013-01-01

    Evidence-based techniques have been increasingly used in the creation of clinical guidelines and the development of recommendations for medical practice. The use of levels of evidence allows the reader to identify the quality of scientific information that supports the recommendations made by experts. The objective of this review was to address current concepts related to the clinical impact, diagnosis, and treatment of Pseudomonas aeruginosa infections in patients with cystic fibrosis. For the preparation of this review, the authors defined a group of questions that would be answered in accordance with the principles of PICO–an acronym based on questions regarding the Patients of interest, Intervention being studied, Comparison of the intervention, and Outcome of interest. For each question, a structured review of the literature was performed using the Medline database in order to identify the studies with the methodological design most appropriate to answering the question. The questions were designed so that each of the authors could write a response. A first draft was prepared and discussed by the group. Recommendations were then made on the basis of the level of scientific evidence, in accordance with the classification system devised by the Oxford Centre for Evidence-Based Medicine, as well as the level of agreement among the members of the group. PMID:24068273

  15. Molecular detection of metallo-β-lactamase gene blaVIM-1 in imipenem-resistant Pseudomonas aeruginosa strains isolated from hospitalized patients in the hospitals of Isfahan

    PubMed Central

    Sedighi, Mansour; Vaez, Hamid; Moghoofeie, Mohsen; Hadifar, Shima; Oryan, Golfam; Faghri, Jamshid

    2015-01-01

    Background: Pseudomonas aeruginosa is an opportunistic human pathogen that causes serious problems, especially in people, who have immunodeficiency. In recent times, metallo-β-lactamase (MBLs) resistance in this bacterium has led to some difficulties in treating bacterial infections. The metallo-beta-lactamase family of genes, including blaVIM-1, is being reported with increasing frequency worldwide. The aim of this study is the detection of the metallo-β-lactamase gene blaVIM-1 in imipenem-resistant P. aeruginosa (IRPA) strains isolated from hospitalized patients. Materials and Methods: In this study, 106 P. aeruginosa samples were isolated from various nosocomial infections. The isolates were identified, tested for susceptibility to various antimicrobial agents by the Kirby-Bauer disk diffusion method, and all the imipenem-resistant isolates were screened for the presence of MBLs by using the combined disk (IMP-EDTA). The minimal inhibitory concentration (MIC) of imipenem was determined by E-test on the Mueller-Hinton agar. To detect the blaVIM-1 gene, the isolates were subjected to a polymerase chain reaction (PCR). Results: Of all the P. aeruginosa isolates, 62 (58.5%) were found to be imipenem-resistant P. aeruginosa (MIC ≥32 μg/ml). Twenty-six (42%) of the imipenem-resistant isolates were MBL positive. None of these isolates carried the blaVIM-1 gene using the PCR assay. Conclusion: The results demonstrated the serious therapeutic threat of the MBL-producing P. aeruginosa populations. The rate of imipenem resistance due to MBL was increased dramatically. Early detection and infection-control practices are the best antimicrobial strategies for this organism. None of MBL-producing isolates in this study carry the blaVIM-1 gene; therefore, another gene in the MBL family should be investigated. PMID:25802826

  16. Real-time PCR based analysis of metal resistance genes in metal resistant Pseudomonas aeruginosa strain J007.

    PubMed

    Choudhary, Sangeeta; Sar, Pinaki

    2016-07-01

    A uranium (U)-resistant and -accumulating Pseudomonas aeruginosa strain was characterized to assess the response of toxic metals toward its growth and expression of metal resistance determinants. The bacterium showed MIC (minimum inhibitory concentration) values of 6, 3, and 2 mM for Zn, Cu, and Cd, respectively; with resistance phenotype conferred by periplasmic Cu sequestering copA and RND type heavy metal efflux czcA genes. Real-time PCR-based expression analysis revealed significant upregulation of both these genes upon exposure to low concentrations of metals for short duration, whereas the global stress response gene sodA encoding superoxide dismutase enzyme was upregulated only at higher metal concentrations or longer exposure time. It could also be inferred that copA and czcA are involved in providing resistance only at low metal concentrations, whereas involvement of "global stress response" phenomenon (expression of sodA) at higher metal concentration or increased exposure was evident. This study provides significant understanding of the adaptive response of bacteria surviving in metal and radionuclide contaminated environments along with the development of real-time PCR-based quantification method of using metal resistance genes as biomarker for monitoring relevant bacteria in such habitats.

  17. Changes in secondary metabolic profiles of Microcystis aeruginosa strains in response to intraspecific interactions

    PubMed Central

    Briand, Enora; Bormans, Myriam; Gugger, Muriel; Dorrestein, Pieter C.; Gerwick, William H.

    2016-01-01

    Summary The cyanobacteria Microcystis proliferate in freshwater ecosystems and produce bioactive compounds including the harmful toxins microcystins (MC). These secondary metabolites play an important role in shaping community composition through biotic interactions although their role and mode of regulation are poorly understood. As natural cyanobacterial populations include producing and non-producing strains, we tested if the production of a range of peptides by coexisting cells could be regulated through intraspecific interactions. With an innovative co-culturing chamber together with advanced mass spectrometry (MS) techniques, we monitored the growth and compared the metabolic profiles of a MC-producing as well as two non-MC-producing Microcystis strains under mono- and co-culture conditions. In monocultures, these strains grew comparably; however, the non-MC-producing mutant produced higher concentrations of cyanopeptolins, aerucyclamides and aeruginosins than the wild type. Physiological responses to co-culturing were reflected in a quantitative change in the production of the major peptides. Using a MS/MS-based molecular networking approach, we identified new analogues of known classes of peptides as well as new compounds. This work provides new insights into the factors that regulate the production of MC and other secondary metabolites in cyanobacteria, and suggests interchangeable or complementary functions allowing bloom-forming cyanobacteria to efficiently colonize and dominate in fluctuating aquatic environments. PMID:25980449

  18. Widespread of ESBL- and carbapenemase GES-type genes on carbapenem-resistant Pseudomonas aeruginosa clinical isolates: a multicenter study in Mexican hospitals.

    PubMed

    Garza-Ramos, Ulises; Barrios, Humberto; Reyna-Flores, Fernando; Tamayo-Legorreta, Elsa; Catalan-Najera, Juan C; Morfin-Otero, Rayo; Rodríguez-Noriega, Eduardo; Volkow, Patricia; Cornejo-Juarez, Patricia; González, Alejandra; Gaytan-Martinez, Jesus; Del Rocío Gónzalez-Martínez, Marisela; Vazquez-Farias, Maria; Silva-Sanchez, Jesus

    2015-02-01

    The present work describes a prevalence of 36.2% of carbapenemases IMP-, VIM-, and GES-type on 124 imipenem-resistant Pseudomonas aeruginosa clinical isolates. The ESBL GES-19 and carbapenemase GES-20 genes were the most prevalent (84.4%) β-lactamases among imipenem-resistant P. aeruginosa clinical isolates in Mexico. These genes are chromosomal encoded on embedded class 1 integron arrays.

  19. Biochemical Characterization of Inducible 'Reductase' Component of Benzoate Dioxygenase and Phthalate Isomer Dioxygenases from Pseudomonas aeruginosa strain PP4.

    PubMed

    Karandikar, Rohini; Badri, Abinaya; Phale, Prashant S

    2015-09-01

    The first step involved in the degradation of phthalate isomers (phthalate, isophthalate and terephthalate) is the double hydroxylation by respective aromatic-ring hydroxylating dioxygenases. These are two component enzymes consisting of 'oxygenase' and 'reductase' components. Soil isolate Pseudomonas aeruginosa strain PP4 degrades phthalate isomers via protocatechuate and benzoate via catechol 'ortho' ring cleavage pathway. Metabolic studies suggest that strain PP4 has carbon source-specific inducible phthalate isomer dioxygenase and benzoate dioxygenase. Thus, it was of interest to study the properties of reductase components of these enzymes. Reductase activity from phthalate isomer-grown cells was 3-5-folds higher than benzoate grown cells. In-gel activity staining profile showed a reductase activity band of R f 0.56 for phthalate isomer-grown cells as compared to R f 0.73 from benzoate-grown cells. Partially purified reductase components from phthalate isomer grown cells showed K m in the range of 30-40 μM and V max = 34-48 μmol min(-1) mg(-1). However, reductase from benzoate grown cells showed K m = 49 μM and V max = 10 μmol min(-1) mg(-1). Strikingly similar molecular and kinetic properties of reductase component from phthalate isomer-grown cells suggest that probably the same reductase component is employed in three phthalate isomer dioxygenases. However, reductase component is different, with respect to kinetic properties and zymogram analysis, from benzoate-grown cells when compared to that from phthalate isomer grown cells of PP4.

  20. Evaluate the Relationship Between Class 1 Integrons and Drug Resistance Genes in Clinical Isolates of Pseudomonas aeruginosa

    PubMed Central

    Hosseini, Seyed Mohammad Javad; Naeini, Niloofar Shoaee; Khaledi, Azad; Daymad, Seyede Fatemeh; Esmaeili, Davoud

    2016-01-01

    Background: The prevalence of resistant Pseudomonas aeruginosa isolates is increasing and it is considered as one of the major public health concerns in the world. The association between integrons and drug resistance has been proven and evidences suggest that integrons are coding and responsible for dissemination of antibiotic resistance among P. aeruginosa isolates. Objective: This study is aimed to evaluate the relationship between class 1 integrons and drug resistance genes in clinical isolates of P. aeruginosa from burn patients. Methods: 100 isolates of P. aeruginosa were collected from burn patients hospitalized in the skin ward of Shahid Motahari hospital and susceptibility testing was performed by disk diffusion method (Kirby-Bauer). Then DNA was extracted and PCR technique was performed for the detection of class 1 integrons and drug resistance genes. Then data was analyzed using SPSS software. Results: The most effective antibiotic was polymyxin B with sensitivity 100%, and the most resistance was observed to the ciprofloxacin (93%) and amikacin (67%), respectively. The maximum and lowest frequencies of drug resistance genes belonged to the aac (6 ') - 1, VEB-1 with prevalence rate 93% and 10%, respectively. The statistical Chi-square test did not find any significant correlation between class 1 integrons and drug resistance genes (p˃ 0.05). Conclusion: Although no significant correlation between class 1 integrons and drug resistance was observed, but the resistance rate to antibiotics tested among P. aeruginosa isolates was high. So, surveillance, optimization and strict consideration of antimicrobial use and control of infection are necessary. PMID:28077975

  1. Population Structure of Clinical Pseudomonas aeruginosa from West and Central African Countries

    PubMed Central

    Cholley, Pascal; Ka, Roughyatou; Guyeux, Christophe; Thouverez, Michelle; Guessennd, Nathalie; Ghebremedhin, Beniam; Frank, Thierry; Bertrand, Xavier; Hocquet, Didier

    2014-01-01

    Background Pseudomonas aeruginosa (PA) has a non-clonal, epidemic population with a few widely distributed and frequently encountered sequence types (STs) called ‘high-risk clusters’. Clinical P. aeruginosa (clinPA) has been studied in all inhabited continents excepted in Africa, where a very few isolates have been analyzed. Here, we characterized a collection of clinPA isolates from four countries of West and Central Africa. Methodology 184 non-redundant isolates of clinPA from hospitals of Senegal, Ivory Coast, Nigeria, and Central African Republic were genotyped by MLST. We assessed their resistance level to antibiotics by agar diffusion and identified the extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs) by sequencing. The population structure of the species was determined by a nucleotide-based analysis of the entire PA MLST database and further localized on the phylogenetic tree (i) the sequence types (STs) of the present collection, (ii) the STs by continents, (iii) ESBL- and MBL-producing STs from the MLST database. Principal Findings We found 80 distinct STs, of which 24 had no relationship with any known STs. ‘High-risk’ international clonal complexes (CC155, CC244, CC235) were frequently found in West and Central Africa. The five VIM-2-producing isolates belonged to CC233 and CC244. GES-1 and GES-9 enzymes were produced by one CC235 and one ST1469 isolate, respectively. We showed the spread of ‘high-risk’ international clonal complexes, often described as multidrug-resistant on other continents, with a fully susceptible phenotype. The MBL- and ESBL-producing STs were scattered throughout the phylogenetic tree and our data suggest a poor association between a continent and a specific phylogroup. Conclusions ESBL- and MBL-encoding genes are borne by both successful international clonal complexes and distinct local STs in clinPA of West and Central Africa. Furthermore, our data suggest that the spread of a ST could be

  2. AmpG Inactivation Restores Susceptibility of Pan-β-Lactam-Resistant Pseudomonas aeruginosa Clinical Strains▿

    PubMed Central

    Zamorano, Laura; Reeve, Thomas M.; Juan, Carlos; Moyá, Bartolomé; Cabot, Gabriel; Vocadlo, David J.; Mark, Brian L.; Oliver, Antonio

    2011-01-01

    Constitutive AmpC hyperproduction is the most frequent mechanism of resistance to the weak AmpC inducers antipseudomonal penicillins and cephalosporins. Previously, we demonstrated that inhibition of the β-N-acetylglucosaminidase NagZ prevents and reverts this mechanism of resistance, which is caused by ampD and/or dacB (PBP4) mutations in Pseudomonas aeruginosa. In this work, we compared NagZ with a second candidate target, the AmpG permease for GlcNAc-1,6-anhydromuropeptides, for their ability to block AmpC expression pathways. Inactivation of nagZ or ampG fully restored the susceptibility and basal ampC expression of ampD or dacB laboratory mutants and impaired the emergence of one-step ceftazidime-resistant mutants in population analysis experiments. Nevertheless, only ampG inactivation fully blocked ampC induction, reducing the MICs of the potent AmpC inducer imipenem from 2 to 0.38 μg/ml. Moreover, through population analysis and characterization of laboratory mutants, we showed that ampG inactivation minimized the impact on resistance of the carbapenem porin OprD, reducing the MIC of imipenem for a PAO1 OprD mutant from >32 to 0.5 μg/ml. AmpG and NagZ targets were additionally evaluated in three clinical isolates that are pan-β-lactam resistant due to AmpC hyperproduction, OprD inactivation, and overexpression of several efflux pumps. A marked increase in susceptibility to ceftazidime and piperacillin-tazobactam was observed in both cases, while only ampG inactivation fully restored wild-type imipenem susceptibility. Susceptibility to meropenem, cefepime, and aztreonam was also enhanced, although to a lower extent due to the high impact of efflux pumps on the activity of these antibiotics. Thus, our results suggest that development of small-molecule inhibitors of AmpG could provide an excellent strategy to overcome the relevant mechanisms of resistance (OprD inactivation plus AmpC induction) to imipenem, the only currently available β-lactam not

  3. Fingerprint Analysis and Identification of Strains ST309 as a Potential High Risk Clone in a Pseudomonas aeruginosa Population Isolated from Children with Bacteremia in Mexico City

    PubMed Central

    Morales-Espinosa, Rosario; Delgado, Gabriela; Espinosa, Luis F.; Isselo, Dassaev; Méndez, José L.; Rodriguez, Cristina; Miranda, Guadalupe; Cravioto, Alejandro

    2017-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen and is associated with nosocomial infections. Its ability to thrive in a broad range of environments is due to a large and diverse genome of which its accessory genome is part. The objective of this study was to characterize P. aeruginosa strains isolated from children who developed bacteremia, using pulse-field gel electrophoresis, and in terms of its genomic islands, virulence genes, multilocus sequence type, and antimicrobial susceptibility. Our results showed that P. aeruginosa strains presented the seven virulence genes: toxA, lasB, lecA, algR, plcH, phzA1, and toxR, a type IV pilin alleles (TFP) group I or II. Additionally, we detected a novel pilin and accessory gene, expanding the number of TFP alleles to group VI. All strains presented the PAPI-2 Island and the majority were exoU+ and exoS+ genotype. Ten percent of the strains were multi-drug resistant phenotype, 18% extensively drug-resistant, 68% moderately resistant and only 3% were susceptible to all the antimicrobial tested. The most prevalent acquired β-Lactamase was KPC. We identified a group of ST309 strains, as a potential high risk clone. Our finding also showed that the strains isolated from patients with bacteremia have important virulence factors involved in colonization and dissemination as: a TFP group I or II; the presence of the exoU gene within the PAPI-2 island and the presence of the exoS gene. PMID:28298909

  4. Fingerprint Analysis and Identification of Strains ST309 as a Potential High Risk Clone in a Pseudomonas aeruginosa Population Isolated from Children with Bacteremia in Mexico City.

    PubMed

    Morales-Espinosa, Rosario; Delgado, Gabriela; Espinosa, Luis F; Isselo, Dassaev; Méndez, José L; Rodriguez, Cristina; Miranda, Guadalupe; Cravioto, Alejandro

    2017-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen and is associated with nosocomial infections. Its ability to thrive in a broad range of environments is due to a large and diverse genome of which its accessory genome is part. The objective of this study was to characterize P. aeruginosa strains isolated from children who developed bacteremia, using pulse-field gel electrophoresis, and in terms of its genomic islands, virulence genes, multilocus sequence type, and antimicrobial susceptibility. Our results showed that P. aeruginosa strains presented the seven virulence genes: toxA, lasB, lecA, algR, plcH, phzA1, and toxR, a type IV pilin alleles (TFP) group I or II. Additionally, we detected a novel pilin and accessory gene, expanding the number of TFP alleles to group VI. All strains presented the PAPI-2 Island and the majority were exoU+ and exoS+ genotype. Ten percent of the strains were multi-drug resistant phenotype, 18% extensively drug-resistant, 68% moderately resistant and only 3% were susceptible to all the antimicrobial tested. The most prevalent acquired β-Lactamase was KPC. We identified a group of ST309 strains, as a potential high risk clone. Our finding also showed that the strains isolated from patients with bacteremia have important virulence factors involved in colonization and dissemination as: a TFP group I or II; the presence of the exoU gene within the PAPI-2 island and the presence of the exoS gene.

  5. Draft Genome Sequence of Textile Azo Dye-Decolorizing and -Degrading Pseudomonas aeruginosa Strain PFK10, Isolated from the Common Effluent Treatment Plant of the Ankleshwar Industrial Area of Gujarat, India.

    PubMed

    Faldu, P R; Kothari, V V; Kothari, C R; Rawal, C M; Domadia, K K; Patel, P A; Bhimani, H D; Raval, V H; Parmar, N R; Nathani, N M; Koringa, P G; Joshi, C G; Kothari, R K

    2014-02-06

    Here, we report the draft genome sequence of Pseudomonas aeruginosa strain PFK10, isolated from the common effluent treatment plant (CETP) of the Ankleshwar industrial area of Gujarat, India. The 6.04-Mb draft genome sequence of strain PFK10 provides information about the genes encoding enzymes that enable the strain to decolorize and degrade textile azo dye.

  6. Draft Genome Sequence of Textile Azo Dye-Decolorizing and -Degrading Pseudomonas aeruginosa Strain PFK10, Isolated from the Common Effluent Treatment Plant of the Ankleshwar Industrial Area of Gujarat, India

    PubMed Central

    Faldu, P. R.; Kothari, V. V.; Kothari, C. R.; Rawal, C. M.; Domadia, K. K.; Patel, P. A.; Bhimani, H. D.; Raval, V. H.; Parmar, N. R.; Nathani, N. M.; Koringa, P. G.; Joshi, C. G.

    2014-01-01

    Here, we report the draft genome sequence of Pseudomonas aeruginosa strain PFK10, isolated from the common effluent treatment plant (CETP) of the Ankleshwar industrial area of Gujarat, India. The 6.04-Mb draft genome sequence of strain PFK10 provides information about the genes encoding enzymes that enable the strain to decolorize and degrade textile azo dye. PMID:24503984

  7. Profile of Virulence Factors in the Multi-Drug Resistant Pseudomonas aeruginosa Strains of Human Urinary Tract Infections (UTI)

    PubMed Central

    Habibi, Asghar; Honarmand, Ramin

    2015-01-01

    Background: Putative virulence factors are responsible for the pathogenicity of UTIs caused by Pseudomonas aeruginosa (P. aeruginosa). Resistance of P. aeruginosa to commonly used antibiotics is caused by the extreme overprescription of those antibiotics. Objectives: The goal of the present study was to investigate the prevalence of virulence factors and the antibiotic resistance patterns of P. aeruginosa isolates in UTI cases in Iran. Patients and Methods: Two hundred and fifty urine samples were collected from patients who suffered from UTIs. Samples were cultured immediately, and those that were P. aeruginosa-positive were analyzed for the presence of virulence genes using polymerase chain reaction (PCR) testing. Antimicrobial susceptibility testing (AST) was performed using the disk diffusion method. Results: Of the 250 urine samples analyzed, 8 samples (3.2%) were positive for P. aeruginosa. The prevalence of P. aeruginosa in male and female patients was 2.7% and 3.5%, respectively, (P = 0.035). In patients less than 10 years old, it was 4.2%, and in patients more than 55 years old, it was 4.2%. These were the most commonly infected groups. The highest levels of resistance were seen against ampicillin (87.5%), norfloxacin (62.5%), gentamycin (62.5%), amikacin (62.5%), and aztreonam (62.5%), while the lowest were seen for meropenem (0%), imipenem (12.5%), and polymyxin B (12.5%). LasB (87.5%), pclH (75%), pilB (75%), and exoS (75%) were the most commonly detected virulence factors in the P. aeruginosa isolates. Conclusions: It is logical to first prescribe meropenem, imipenem, and polymyxin B in cases of UTIs caused by P. aeruginosa. Medical practitioners should be aware of the presence of levels of antibiotic resistance in hospitalized UTI patients in Iran. PMID:26756017

  8. Alterations of OprD in Carbapenem-Intermediate and -Susceptible Strains of Pseudomonas aeruginosa Isolated from Patients with Bacteremia in a Spanish Multicenter Study

    PubMed Central

    Cabot, Gabriel; Rodríguez, Cristina; Roman, Elena; Tubau, Fe; Macia, María D.; Moya, Bartolomé; Zamorano, Laura; Suárez, Cristina; Peña, Carmen; Domínguez, María A.; Moncalián, Gabriel; Oliver, Antonio; Martínez-Martínez, Luis

    2012-01-01

    We investigated the presence of OprD mutations in 60 strains of metallo-ß-lactamase-negative Pseudomonas aeruginosa intermediately susceptible (IS [n = 12]; MIC = 8 μg/ml) or susceptible (S [n = 48]; MICs ≤ 1 to 4 μg/ml) to imipenem and/or meropenem that were isolated from patients with bacteremia in order to evaluate their impact on carbapenem susceptibility profiles. The presence of mutations in oprD was detected by sequencing analysis. OprD expression was assessed by both outer membrane protein (OMP) analysis and real-time PCR (RT-PCR). Fourteen (23%) isolates had an OprD identical to that of PAO1, and OprD modifications were detected in 46 isolates (77%). Isolates were classified as OprD “full-length types” (T1 [n = 40, including both wild-type OprD and variants showing several polymorphisms]) and OprD “deficient types” (T2 [n = 3 for OprD frameshift mutations] and T3 [n = 17 for premature stop codons in oprD]). RT-PCR showed that 5 OprD type T1 isolates presented reduced transcription of oprD (0.1- to 0.4-fold compared to PAO1), while oprD levels increased more than 2-fold over that seen with PAO1 in 4 OprD type T1 isolates. A total of 50% of the isolates belonging to OprD “deficient types” were susceptible to both carbapenems, and 40% were susceptible to meropenem and intermediately susceptible to imipenem. Only one isolate (5%) within this group was intermediately susceptible to both carbapenems, and one (5%) was susceptible to imipenem and intermediately susceptible to meropenem. We concluded that OprD inactivating mutations in clinical isolates of P. aeruginosa are not restricted only to carbapenem-resistant isolates but are also found in isolates with imipenem or meropenem MICs of only 0.06 to 4 μg/ml. PMID:22290967

  9. Growing Menace of Antibacterial Resistance in Clinical Isolates of Pseudomonas aeruginosa in Nepal: An Insight of Beta-Lactamase Production

    PubMed Central

    Dhital, Rabindra; Puri, Ram; Chaudhary, Niraj; Khatiwada, Suresh

    2016-01-01

    Introduction. Pseudomonas aeruginosa is the most frequently isolated organism as it acts as the opportunistic pathogen and can cause infections in immunosuppressed patients. The production of different types of beta-lactamases renders this organism resistant to many commonly used antimicrobials. Therefore, the aim of this study was to document the antibiotic resistance rate in Pseudomonas aeruginosa isolated from different clinical specimens. Methods. Pseudomonas aeruginosa recovered was identified by standard microbiological methods. Antibiotic susceptibility testing was performed by modified Kirby-Bauer disc diffusion method following Clinical and Laboratory Standard Institute (CLSI) guidelines and all the suspected isolates were tested for the production of ESBLs, MBLs, and AmpC. Results. Out of total (178) isolates, 83.1% were recovered from the inpatient department (IPD). Majority of the isolates mediated resistance towards the beta-lactam antibiotics, while nearly half of the isolates were resistant to ciprofloxacin. Most of the aminoglycosides used showed resistance rate up to 75% but amikacin proved to be better option. No resistance to polymyxin was observed. ESBLs, MBLs, and AmpC mediated resistance was seen in 33.1%, 30.9%, and 15.7% isolates, respectively. Conclusions. Antibiotic resistance rate and beta-lactamase mediated resistance were high. Thus, regular surveillance of drug resistance is of utmost importance. PMID:27642599

  10. Label-free SRM-based relative quantification of antibiotic resistance mechanisms in Pseudomonas aeruginosa clinical isolates.

    PubMed

    Charretier, Yannick; Köhler, Thilo; Cecchini, Tiphaine; Bardet, Chloé; Cherkaoui, Abdessalam; Llanes, Catherine; Bogaerts, Pierre; Chatellier, Sonia; Charrier, Jean-Philippe; Schrenzel, Jacques

    2015-01-01

    Both acquired and intrinsic mechanisms play a crucial role in Pseudomonas aeruginosa antibiotic resistance. Many clinically relevant resistance mechanisms result from changes in gene expression, namely multidrug efflux pump overproduction, AmpC β-lactamase induction or derepression, and inactivation or repression of the carbapenem-specific porin OprD. Changes in gene expression are usually assessed using reverse-transcription quantitative real-time PCR (RT-qPCR) assays. Here, we evaluated label-free Selected Reaction Monitoring (SRM)-based mass spectrometry to directly quantify proteins involved in antibiotic resistance. We evaluated the label-free SRM using a defined set of P. aeruginosa isolates with known resistance mechanisms and compared it with RT-qPCR. Referring to efflux systems, we found a more robust relative quantification of antibiotic resistance mechanisms by SRM than RT-qPCR. The SRM-based approach was applied to a set of clinical P. aeruginosa isolates to detect antibiotic resistance proteins. This multiplexed SRM-based approach is a rapid and reliable method for the simultaneous detection and quantification of resistance mechanisms and we demonstrate its relevance for antibiotic resistance prediction.

  11. Label-free SRM-based relative quantification of antibiotic resistance mechanisms in Pseudomonas aeruginosa clinical isolates

    PubMed Central

    Charretier, Yannick; Köhler, Thilo; Cecchini, Tiphaine; Bardet, Chloé; Cherkaoui, Abdessalam; Llanes, Catherine; Bogaerts, Pierre; Chatellier, Sonia; Charrier, Jean-Philippe; Schrenzel, Jacques

    2015-01-01

    Both acquired and intrinsic mechanisms play a crucial role in Pseudomonas aeruginosa antibiotic resistance. Many clinically relevant resistance mechanisms result from changes in gene expression, namely multidrug efflux pump overproduction, AmpC β-lactamase induction or derepression, and inactivation or repression of the carbapenem-specific porin OprD. Changes in gene expression are usually assessed using reverse-transcription quantitative real-time PCR (RT-qPCR) assays. Here, we evaluated label-free Selected Reaction Monitoring (SRM)-based mass spectrometry to directly quantify proteins involved in antibiotic resistance. We evaluated the label-free SRM using a defined set of P. aeruginosa isolates with known resistance mechanisms and compared it with RT-qPCR. Referring to efflux systems, we found a more robust relative quantification of antibiotic resistance mechanisms by SRM than RT-qPCR. The SRM-based approach was applied to a set of clinical P. aeruginosa isolates to detect antibiotic resistance proteins. This multiplexed SRM-based approach is a rapid and reliable method for the simultaneous detection and quantification of resistance mechanisms and we demonstrate its relevance for antibiotic resistance prediction. PMID:25713571

  12. Sulphide Resistance in the Cyanobacterium Microcystis aeruginosa: a Comparative Study of Morphology and Photosynthetic Performance Between the Sulphide-Resistant Mutant and the Wild-Type Strain.

    PubMed

    Bañares-España, Elena; del Mar Fernández-Arjona, María; García-Sánchez, María Jesús; Hernández-López, Miguel; Reul, Andreas; Mariné, Mariona Hernández; Flores-Moya, Antonio

    2016-05-01

    The cyanobacterium Microcystis aeruginosa is a mesophilic freshwater organism, which cannot tolerate sulphide. However, it was possible to isolate a sulphide-resistant (S(r)) mutant strain that was able to survive in a normally lethal medium sulphide. In order to evaluate the cost of the mutation conferring sulphide resistance in the S(r) strain of M. aeruginosa, the morphology and the photosynthetic performance were compared to that found in the wild-type, sulphide-sensitive (S(s)) strain. An increase in size and a disrupted morphology was observed in S(r) cells in comparison to the S(s) counterpart. Phycoerythrin and phycocyanin levels were higher in the S(r) than in the S(s) cells, whereas a higher carotenoid content, per unit volume, was found in the S(s) strain. The irradiance-saturated photosynthetic oxygen-production rate (GPR max) and the photosynthetic efficiency (measured both by oxygen production and fluorescence, α(GPR) and α(ETR)) were lower in the S(r) strain than in the wild-type. These results appear to be the result of package effect. On the other hand, the S(r) strain showed higher quantum yield of non-photochemical quenching, especially those regulated mechanisms (estimated throughout qN and Y(NPQ)) and a significantly lower slope in the maximum quantum yield of light-adapted samples (Fv'/Fm') compared to the S(s) strain. These findings point to a change in the regulation of the quenching of the transition states (qT) in the S(r) strain which may be generated by a change in the distribution of thylakoidal membranes, which somehow could protect metalloenzymes of the electron transport chain from the lethal effect of sulphide.

  13. Homogentisate 1-2-Dioxygenase Downregulation in the Chronic Persistence of Pseudomonas aeruginosa Australian Epidemic Strain-1 in the CF Lung.

    PubMed

    Harmer, Christopher J; Wynn, Matthew; Pinto, Rachel; Cordwell, Stuart; Rose, Barbara R; Harbour, Colin; Triccas, James A; Manos, Jim

    2015-01-01

    Some Pseudomonas aeruginosa strains including Australian Epidemic Strain-1 (AES-1 or AUS-01) cause persistent chronic infection in cystic fibrosis (CF) patients, with greater morbidity and mortality. Factors conferring persistence are largely unknown. Previously we analysed the transcriptomes of AES-1 grown in Luria broth, nematode growth medium for Caenorhabditis elegans assay (both aerobic) and artificial sputum medium (mainly hypoxic). Transcriptional comparisons included chronic AES-1 strains against PAO1 and acute AES-1 (AES-1R) against its chronic isogen (AES-1M), isolated 10.5 years apart from a CF patient and not eradicated in the meantime. Prominent amongst genes downregulated in AES-1M in all comparisons was homogentisate-1-2-dioxygenase (hmgA); an oxygen-dependent gene known to be mutationally deactivated in many chronic infection strains of P. aeruginosa. To investigate if hmgA downregulation and deactivation gave similar virulence persistence profiles, a hmgA mutant made in UCBPP-PA14 utilising RedS-recombinase and AES-1M were assessed in the C. elegans virulence assay, and the C57BL/6 mouse for pulmonary colonisation and TNF-α response. In C. elegans, hmgA deactivation resulted in significantly increased PA14 virulence while hmgA downregulation reduced AES-1M virulence. AES-1M was significantly more persistent in mouse lung and showed a significant increase in TNF-α (p<0.0001), sustained even with no detectable bacteria. PA14ΔhmgA did not show increased TNF-α. This study suggests that hmgA may have a role in P. aeruginosa persistence in chronic infection and the results provide a starting point for clarifying the role of hmgA in chronic AES-1.

  14. Differences in antimicrobial susceptibility breakpoints for Pseudomonas aeruginosa, isolated from blood cultures, set by the Clinical and Laboratory Standards Institute (CLSI) and the Japanese Society of Chemotherapy.

    PubMed

    Nakamura, Tatsuya; Shimizu, Chihiro; Kasahara, Mayumi; Nakata, Chiyo; Munakata, Machiko; Takahashi, Hakuo

    2007-02-01

    A study was made of the antimicrobial susceptibility to and efficacy of various kinds of antimicrobial agents against 179 strains of Pseudomonas aeruginosa that were isolated from blood cultures at Kansai Medical University Hospital from 1990 through 2004. The annual detection rate was highest in 1994, at 22 strains (6.5%). There were 9 multidrug resistant strains of Pseudomonas aeruginosa (5.0%). Among 14 antimicrobial agents tested for measurements, ciprofloxacin (CPFX) showed the best minimum inhibitory concentration (MIC) 50 value, of 0.25 microg/ml, followed by pazufloxacin (PZFX) and biapenem (BIPM), each at 0.5 microg/ml. When the period of 15 years was divided into three stages, the MIC50 value for each antimicrobial agent was highest in the middle stage (1995 to 1999). Assuming that the percentage of sensitive strains according to the breakpoints set by the Clinical and Laboratory Standards Institute (CLSI) represents the antimicrobial susceptibility rate, amikacin (AMK) showed the best value, of 85.5%. According to the sepsis breakpoint set by the Japanese Society of Chemotherapy (JSC), the efficacy of CPFX showed the highest rate (77.1%) of all the antimicrobial agents tested. Among beta-lactams, BIPM showed the highest efficacy rate, of 67.0%. When the efficacy rates were compared with each other, the difference in efficacy rate between the breakpoint set by the CLSI and the sepsis breakpoint set by the JSC was large for beta-lactams. Comparisons made based on the CLSI criteria showed no difference in cross-resistance rates between CPFX, meropenem (MEPM), and BIPM. However, when comparisons were made using the JSC sepsis breakpoint, MEPM showed a cross-resistance rate of 87.8%, while the rate for BIPM was lower, at 56.1%, with the chi2 test showing a significant difference, at P = 0.0014. In accordance with the pharmacokinetics/pharmacodynamics theory that has been advocated, breakpoints which are more suitable for the clinical setting in Japan should

  15. Interactions of Pseudomonas aeruginosa in predominant biofilm or planktonic forms of existence in mixed culture with Escherichia coli in vitro.

    PubMed

    Kuznetsova, Marina V; Maslennikova, Irina L; Karpunina, Tamara I; Nesterova, Larisa Yu; Demakov, Vitaly A

    2013-09-01

    Pseudomonas aeruginosa and Escherichia coli are known to be involved in mixed communities in diverse niches. In this study we examined the influence of the predominant form of cell existence of and the exometabolite production by P. aeruginosa strains on interspecies interactions, in vitro. Bacterial numbers of P. aeruginosa and E. coli in mixed plankton cultures and biofilms compared with their numbers in single plankton cultures and biofilms changed in a different way, but were in accordance with the form of P. aeruginosa cell existence. The mass of a mixed-species biofilm was greater than the mass of a single-species biofilm. Among the mixed biofilms, the one with the "planktonic" P. aeruginosa strain had the least biomass. The total pyocyanin and pyoverdin levels were found to be lower in all mixed plankton cultures. Despite this, clinical P. aeruginosa strains irrespective of the predominant form of existence ("biofilm" or "planktonic") had a higher total concentration of exometabolites than did the reference strain in 12-24 h mixed cultures. The metabolism of E. coli, according to its bioluminescence, was reduced in mixed cultures, and the decrease was by 20- to 100-fold greater with the clinical Pseudomonas strains than the reference Pseudomonas strain. Thus, both the predominant form of existence of and the exometabolite production by distinct P. aeruginosa strains should be considered to fully understand the interspecies relationship and bacteria survival in natural communities.

  16. Effect of Quorum Quenching Lactonase in Clinical Isolates of Pseudomonas aeruginosa and Comparison with Quorum Sensing Inhibitors.

    PubMed

    Guendouze, Assia; Plener, Laure; Bzdrenga, Janek; Jacquet, Pauline; Rémy, Benjamin; Elias, Mikael; Lavigne, Jean-Philippe; Daudé, David; Chabrière, Eric

    2017-01-01

    Pseudomonas aeruginosa is a Gram negative pathogenic bacterium involved in many human infections including otitis, keratitis, pneumonia, and diabetic foot ulcers. P. aeruginosa uses a communication system, referred to as quorum sensing (QS), to adopt a group behavior by synchronizing the expression of certain genes. Among the regulated traits, secretion of proteases or siderophores, motility and biofilm formation are mainly involved in the pathogenicity. Many efforts have been dedicated to the development of quorum sensing inhibitors (QSI) and quorum quenching (QQ) agents to disrupt QS. QQ enzymes have been particularly considered as they may act in a catalytic way without entering the cell. Here we focus on the lactonase SsoPox which was previously investigated for its ability to degrade the signaling molecules, acyl-homoserine lactones, in particular on the engineered variant SsoPox-W263I. We highlight the potential of SsoPox-W263I to inhibit the virulence of 51 clinical P. aeruginosa isolates from diabetic foot ulcers by decreasing the secretion of two virulence factors, proteases and pyocyanin, as well as biofilm formation. We further compared the effect of SsoPox-W263I to the comprehensively described QSI, 5-fluorouracil and C-30. We found the lactonase SsoPox-W263I to be significantly more effective than the tested QSI at their respective concentration optimum and to retain its activity after immobilization steps, paving the way for future therapeutic applications.

  17. Effect of Quorum Quenching Lactonase in Clinical Isolates of Pseudomonas aeruginosa and Comparison with Quorum Sensing Inhibitors

    PubMed Central

    Guendouze, Assia; Plener, Laure; Bzdrenga, Janek; Jacquet, Pauline; Rémy, Benjamin; Elias, Mikael; Lavigne, Jean-Philippe; Daudé, David; Chabrière, Eric

    2017-01-01

    Pseudomonas aeruginosa is a Gram negative pathogenic bacterium involved in many human infections including otitis, keratitis, pneumonia, and diabetic foot ulcers. P. aeruginosa uses a communication system, referred to as quorum sensing (QS), to adopt a group behavior by synchronizing the expression of certain genes. Among the regulated traits, secretion of proteases or siderophores, motility and biofilm formation are mainly involved in the pathogenicity. Many efforts have been dedicated to the development of quorum sensing inhibitors (QSI) and quorum quenching (QQ) agents to disrupt QS. QQ enzymes have been particularly considered as they may act in a catalytic way without entering the cell. Here we focus on the lactonase SsoPox which was previously investigated for its ability to degrade the signaling molecules, acyl-homoserine lactones, in particular on the engineered variant SsoPox-W263I. We highlight the potential of SsoPox-W263I to inhibit the virulence of 51 clinical P. aeruginosa isolates from diabetic foot ulcers by decreasing the secretion of two virulence factors, proteases and pyocyanin, as well as biofilm formation. We further compared the effect of SsoPox-W263I to the comprehensively described QSI, 5-fluorouracil and C-30. We found the lactonase SsoPox-W263I to be significantly more effective than the tested QSI at their respective concentration optimum and to retain its activity after immobilization steps, paving the way for future therapeutic applications. PMID:28261183

  18. Genotypic comparison of Pantoea agglomerans plant and clinical strains

    PubMed Central

    2009-01-01

    Background Pantoea agglomerans strains are among the most promising biocontrol agents for a variety of bacterial and fungal plant diseases, particularly fire blight of apple and pear. However, commercial registration of P. agglomerans biocontrol products is hampered because this species is currently listed as a biosafety level 2 (BL2) organism due to clinical reports as an opportunistic human pathogen. This study compares plant-origin and clinical strains in a search for discriminating genotypic/phenotypic markers using multi-locus phylogenetic analysis and fluorescent amplified fragment length polymorphisms (fAFLP) fingerprinting. Results Majority of the clinical isolates from culture collections were found to be improperly designated as P. agglomerans after sequence analysis. The frequent taxonomic rearrangements underwent by the Enterobacter agglomerans/Erwinia herbicola complex may be a major problem in assessing clinical associations within P. agglomerans. In the P. agglomerans sensu stricto (in the stricter sense) group, there was no discrete clustering of clinical/biocontrol strains and no marker was identified that was uniquely associated to clinical strains. A putative biocontrol-specific fAFLP marker was identified only in biocontrol strains. The partial ORF located in this band corresponded to an ABC transporter that was found in all P. agglomerans strains. Conclusion Taxonomic mischaracterization was identified as a major problem with P. agglomerans, and current techniques removed a majority of clinical strains from this species. Although clear discrimination between P. agglomerans plant and clinical strains was not obtained with phylogenetic analysis, a single marker characteristic of biocontrol strains was identified which may be of use in strain biosafety determinations. In addition, the lack of Koch's postulate fulfilment, rare retention of clinical strains for subsequent confirmation, and the polymicrobial nature of P. agglomerans clinical reports

  19. Synergistic algicidal effect and mechanism of two diketopiperazines produced by Chryseobacterium sp. strain GLY-1106 on the harmful bloom-forming Microcystis aeruginosa

    PubMed Central

    Guo, Xingliang; Liu, Xianglong; Pan, Jianliang; Yang, Hong

    2015-01-01

    A potent algicidal bacterium isolated from Lake Taihu, Chryseobacterium sp. strain GLY-1106, produces two algicidal compounds: 1106-A (cyclo(4-OH-Pro-Leu)) and 1106-B (cyclo(Pro-Leu)). Both diketopiperazines showed strong algicidal activities against Microcystis aeruginosa, the dominant bloom-forming cyanobacterium in Lake Taihu. Interestingly, these two algicidal compounds functioned synergistically. Compared with individual treatment, combined treatment with cyclo(4-OH-Pro-Leu) and cyclo(Pro-Leu) significantly enhanced algicidal activity, accelerated the increase in intracellular reactive oxygen species (ROS) levels in M. aeruginosa, and further decreased the activities of antioxidases, effective quantum yield and maximal electron transport rate of M. aeruginosa. The results also showed that the algicidal characteristics of cyclo(4-OH-Pro-Leu) are distinct from those of cyclo(Pro-Leu). Cyclo(4-OH-Pro-Leu) mainly interrupted the flux of electron transport in the cyanobacterial photosynthetic system, whereas cyclo(Pro-Leu) mainly inhibited the activity of cyanobacterial intracellular antioxidases. A possible algicidal mechanism for the synergism between cyclo(4-OH-Pro-Leu) and cyclo(Pro-Leu) is proposed, which is in accordance with their distinct algicidal characteristics in individual and combined treatment. These findings suggest that synergism between algicidal compounds might be used as an effective strategy for the future control of Microcystis blooms. PMID:26423356

  20. MrkD1P from Klebsiella pneumoniae Strain IA565 Allows for Coexistence with Pseudomonas aeruginosa and Protection from Protease-Mediated Biofilm Detachment

    PubMed Central

    Childers, Brandon M.; Van Laar, Tricia A.; You, Tao; Clegg, Steven

    2013-01-01

    Biofilm formation and persistence are essential components for the continued survival of pathogens inside the host and constitute a major contributor to the development of chronic wounds with resistance to antimicrobial compounds. Understanding these processes is crucial for control of biofilm-mediated disease. Though chronic wound infections are often polymicrobial in nature, much of the research on chronic wound-related microbes has focused on single-species models. Klebsiella pneumoniae and Pseudomonas aeruginosa are microbes that are often found together in wound isolates and are able to form stable in vitro biofilms, despite the antagonistic nature of P. aeruginosa with other organisms. Mutants of the K. pneumoniae strain IA565 lacking the plasmid-borne mrkD1P gene were less competitive than the wild type in an in vitro dual-species biofilm model with P. aeruginosa (PAO1). PAO1 spent medium inhibited the formation of biofilm of mrkD1P-deficient mutants and disrupted preestablished biofilms, with no effect on IA565 and no effect on the growth of the wild type or mutants. A screen using a two-allele PAO1 transposon library identified the LasB elastase as the secreted effector involved in biofilm disruption, and a purified version of the protein produced results similar to those with PAO1 spent medium. Various other proteases had a similar effect, suggesting that the disruption of the mrkD1P gene causes sensitivity to general proteolytic effects and indicating a role for MrkD1P in protection against host antibiofilm effectors. Our results suggest that MrkD1P allows for competition of K. pneumoniae with P. aeruginosa in a mixed-species biofilm and provides defense against microbial and host-derived proteases. PMID:23980108

  1. Application of the multifactor dimensionality reduction method in evaluation of the roles of multiple genes/enzymes in multidrug-resistant acquisition in Pseudomonas aeruginosa strains.

    PubMed

    Yao, Z; Peng, Y; Bi, J; Xie, C; Chen, X; Li, Y; Ye, X; Zhou, J

    2016-03-01

    Multidrug-resistant Pseudomonas aeruginosa (MDRPA) infections are major threats to healthcare-associated infection control and the intrinsic molecular mechanisms of MDRPA are also unclear. We examined 348 isolates of P. aeruginosa, including 188 MDRPA and 160 non-MDRPA, obtained from five tertiary-care hospitals in Guangzhou, China. Significant correlations were found between gene/enzyme carriage and increased rates of antimicrobial resistance (P < 0·01). gyrA mutation, OprD loss and metallo-β-lactamase (MBL) presence were identified as crucial molecular risk factors for MDRPA acquisition by a combination of univariate logistic regression and a multifactor dimensionality reduction approach. The MDRPA rate was also elevated with the increase in positive numbers of those three determinants (P < 0·001). Thus, gyrA mutation, OprD loss and MBL presence may serve as predictors for early screening of MDRPA infections in clinical settings.

  2. Bulgecin A as a β-lactam enhancer for carbapenem-resistant Pseudomonas aeruginosa and carbapenem-resistant Acinetobacter baumannii clinical isolates containing various resistance mechanisms

    PubMed Central

    Skalweit, Marion J; Li, Mei

    2016-01-01

    Genetic screening of Pseudomonas aeruginosa (PSDA) and Acinetobacter baumannii (ACB) reveals genes that confer increased susceptibility to β-lactams when disrupted, suggesting novel drug targets. One such target is lytic transglycosylase. Bulgecin A (BlgA) is a natural product of Pseudomonas mesoacidophila and a lytic transglycosolase inhibitor that works synergistically with β-lactams targeting PBP3 for Enterobacteriaceae. BlgA also weakly inhibits di-Zn2+ metallo-β-lactamases like L1 of Stenotrophomonas maltophilia. We hypothesized that because of its unique mechanism of action, BlgA could restore susceptibility to carbapenems in carbapenem-resistant PSDA (CR-PSDA) and carbapenem-resistant ACB, as well as ACB resistant to sulbactam. A BlgA-containing extract was prepared using a previously published protocol. CR-PSDA clinical isolates demonstrating a variety of carbapenem resistance mechanisms (VIM-2 carbapenemases, efflux mechanisms, and AmpC producer expression) were characterized with agar dilution minimum inhibitory concentration (MIC) testing and polymerase chain reaction. Growth curves using these strains were prepared using meropenem, BlgA extract, and meropenem plus BlgA extract. A concentrated Blg A extract combined with low concentrations of meropenem, was able to inhibit the growth of clinical strains of CR-PSDA for strains that had meropenem MICs ≥8 mg/L by agar dilution, and a clinical strain of an OXA-24 producing ACB that had a meropenem MIC >32 mg/L and intermediate ampicillin/sulbactam susceptibility. Similar experiments were conducted on a TEM-1 producing ACB strain resistant to sulbactam. BlgA with ampicillin/sulbactam inhibited the growth of this organism. As in Enterobacteriaceae, BlgA appears to restore the efficacy of meropenem in suppressing the growth of CR-PSDA and carbapenem-resistant ACB strains with a variety of common carbapenem resistance mechanisms. BlgA extract also inhibits VIM-2 β-lactamase in vitro. BlgA may prove to be

  3. Changing susceptibility of Pseudomonas aeruginosa isolates from cystic fibrosis patients with the clinical use of newer antibiotics.

    PubMed Central

    Bosso, J A; Allen, J E; Matsen, J M

    1989-01-01

    To detect a change in antibiotic susceptibility patterns in Pseudomonas aeruginosa isolates upon the introduction and clinical use of ciprofloxacin, aztreonam, and ceftazidime, MICs for clinical isolates collected before introduction of the antibiotics, during early clinical use, and later were determined for these and seven other antipseudomonal antibiotics. Concomitant resistance to two or more antibiotics was also studied. Over the three study periods, rates of susceptibility to 9 of the 10 antibiotics decreased. The largest decrease occurred with ceftazidime. Analysis of subsets of isolates from patients treated with ciprofloxacin or aztreonam also showed declining susceptibility to the latter but a stabilization of susceptibility to the former after an initial decline. Concomitant resistance within and among antibiotic classes was common. PMID:2499252

  4. Antibiotic resistance pattern and evaluation of metallo-beta lactamase genes (VIM and IMP) in Pseudomonas aeruginosa strains producing MBL enzyme, isolated from patients with secondary immunodeficiency

    PubMed Central

    Shirani, Kiana; Ataei, Behrouz; Roshandel, Fardad

    2016-01-01

    Background: One of the most common causes of hospital-acquired secondary infections in hospitalized patients is Pseudomonas aeruginosa. The aim of this study is to evaluate the expression of IMP and VIM in Pseudomonas aeruginosa strains (carbapenem resistant and producer MBL enzyme) in patients with secondary immunodeficiency. Materials and Methods: In a cross sectional study, 96 patients with secondary immunodeficiency hospitalized in the Al-Zahra hospital were selected. Carbapenem resistant strains isolated and modified Hodge test was performed in order to confirm the presence of the metallo carbapenemase enzyme. Under the standard conditions they were sent to the central laboratory for investigating nosocomial infection Multiplex PCR. Results: Of 96 samples 28.1% were IMP positive, 5.2% VIM positive and 3.1% both VIM and IMP positive. The prevalence of multidrug resistance in the IMP and/or VIM negative samples was 29%, while all 5 VIM positive samples have had multidrug resistance. Also the prevalence of multi-drug resistance in IMP positive samples were 96.3% and in IMP and VIM positive samples were 100%. According to Fisher’s test, the prevalence of multi-drug resistance based on gene expression has significant difference (P < 0.001). Conclusion: Based on the results of this study it can be concluded that, a significant percentage of patients with secondary immunodeficiency that suffer nosocomial infections with multidrug resistance, especially Pseudomonas aeruginosa, are probably MBL-producing gene positive. Therefore the cause of infection should be considered in the hospital care system to identify their features, the presence of genes involved in the development of multi-drug resistance and antibiotic therapy. PMID:27563634

  5. Clinical and pathologic findings of blue-green algae (Microcystis aeruginosa) intoxication in a dog.

    PubMed

    DeVries, S E; Galey, F D; Namikoshi, M; Woo, J C

    1993-07-01

    A healthy dog developed signs of lethargy and vomiting after ingesting water from a tide pool containing blue-green algae. Fulminant hepatic failure occurred, and the dog was euthanized 52 hours later. At necropsy, the liver was large, friable, and discolored a dark red. Histopathology showed hepatocyte dissociation, degeneration, and necrosis. The alga was identified as Microcystis aeruginosa, a known hepatotoxin. The intraperitoneal administration of lyophilized cell material from the bloom caused hepatic necrosis in mice.

  6. Use of a Multiplex Transcript Method for Analysis of Pseudomonas aeruginosa Gene Expression Profiles in the Cystic Fibrosis Lung.

    PubMed

    Gifford, Alex H; Willger, Sven D; Dolben, Emily L; Moulton, Lisa A; Dorman, Dana B; Bean, Heather; Hill, Jane E; Hampton, Thomas H; Ashare, Alix; Hogan, Deborah A

    2016-10-01

    The discovery of therapies that modulate Pseudomonas aeruginosa virulence or that can eradicate chronic P. aeruginosa lung infections associated with cystic fibrosis (CF) will be advanced by an improved understanding of P. aeruginosa behavior in vivo We demonstrate the use of multiplexed Nanostring technology to monitor relative abundances of P. aeruginosa transcripts across clinical isolates, in serial samples, and for the purposes of comparing microbial physiology in vitro and in vivo The expression of 75 transcripts encoded by genes implicated in CF lung disease was measured in a variety of P. aeruginosa strains as well as RNA serial sputum samples from four P. aeruginosa-colonized subjects with CF collected over 6 months. We present data on reproducibility, the results from different methods of normalization, and demonstrate high concordance between transcript relative abundance data obtained by Nanostring or transcriptome sequencing (RNA-Seq) analysis. Furthermore, we address considerations regarding sequence variation between strains during probe design. Analysis of P. aeruginosa grown in vitro identified transcripts that correlated with the different phenotypes commonly observed in CF clinical isolates. P. aeruginosa transcript profiles in RNA from CF sputum indicated alginate production in vivo, and transcripts involved in quorum-sensing regulation were less abundant in sputum than strains grown in the laboratory. P. aeruginosa gene expression patterns from sputum clustered closely together relative to patterns for laboratory-grown cultures; in contrast, laboratory-grown P. aeruginosa showed much greater transcriptional variation with only loose clustering of strains with different phenotypes. The clustering within and between subjects was surprising in light of differences in inhaled antibiotic and respiratory symptoms, suggesting that the pathways represented by these 75 transcripts are stable in chronic CF P. aeruginosa lung infections.

  7. Use of a Multiplex Transcript Method for Analysis of Pseudomonas aeruginosa Gene Expression Profiles in the Cystic Fibrosis Lung

    PubMed Central

    Willger, Sven D.; Dolben, Emily L.; Moulton, Lisa A.; Dorman, Dana B.; Bean, Heather; Hill, Jane E.; Hampton, Thomas H.; Ashare, Alix

    2016-01-01

    The discovery of therapies that modulate Pseudomonas aeruginosa virulence or that can eradicate chronic P. aeruginosa lung infections associated with cystic fibrosis (CF) will be advanced by an improved understanding of P. aeruginosa behavior in vivo. We demonstrate the use of multiplexed Nanostring technology to monitor relative abundances of P. aeruginosa transcripts across clinical isolates, in serial samples, and for the purposes of comparing microbial physiology in vitro and in vivo. The expression of 75 transcripts encoded by genes implicated in CF lung disease was measured in a variety of P. aeruginosa strains as well as RNA serial sputum samples from four P. aeruginosa-colonized subjects with CF collected over 6 months. We present data on reproducibility, the results from different methods of normalization, and demonstrate high concordance between transcript relative abundance data obtained by Nanostring or transcriptome sequencing (RNA-Seq) analysis. Furthermore, we address considerations regarding sequence variation between strains during probe design. Analysis of P. aeruginosa grown in vitro identified transcripts that correlated with the different phenotypes commonly observed in CF clinical isolates. P. aeruginosa transcript profiles in RNA from CF sputum indicated alginate production in vivo, and transcripts involved in quorum-sensing regulation were less abundant in sputum than strains grown in the laboratory. P. aeruginosa gene expression patterns from sputum clustered closely together relative to patterns for laboratory-grown cultures; in contrast, laboratory-grown P. aeruginosa showed much greater transcriptional variation with only loose clustering of strains with different phenotypes. The clustering within and between subjects was surprising in light of differences in inhaled antibiotic and respiratory symptoms, suggesting that the pathways represented by these 75 transcripts are stable in chronic CF P. aeruginosa lung infections. PMID:27481238

  8. 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

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

    PubMed Central

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

    2017-01-01

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

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

    PubMed

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

    2017-01-01

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

  11. Engineering the central biosynthetic and secondary metabolic pathways of Pseudomonas aeruginosa strain PA1201 to improve phenazine-1-carboxylic acid production.

    PubMed

    Jin, Kaiming; Zhou, Lian; Jiang, Haixia; Sun, Shuang; Fang, Yunling; Liu, Jianhua; Zhang, Xuehong; He, Ya-Wen

    2015-11-01

    The secondary metabolite phenazine-1-carboxylic acid (PCA) is an important component of the newly registered biopesticide Shenqinmycin. We used a combined method involving gene, promoter, and protein engineering to modify the central biosynthetic and secondary metabolic pathways in the PCA-producing Pseudomonas aeruginosa strain PA1201. The PCA yield of the resulting strain PA-IV was increased 54.6-fold via the following strategies: (1) blocking PCA conversion and enhancing PCA efflux pumping; (2) increasing metabolic flux towards the PCA biosynthetic pathway through the over-production of two DAHP synthases and blocking the synthesis of 21 secondary metabolites; (3) increasing the PCA precursor supply through the engineering of five chorismate-utilizing enzymes; (4) engineering the promoters of two PCA biosynthetic gene clusters. Strain PA-IV produced 9882 mg/L PCA in fed-batch fermentation, which is twice as much as that produced by the current industrial strain. Strain PA-IV was also genetically stable and comparable to Escherichia coli in cytotoxicity.

  12. Fast and specific detection of Pseudomonas Aeruginosa from other pseudomonas species by PCR

    PubMed Central

    Jami Al-Ahmadi, G.; Zahmatkesh Roodsari, R.

    2016-01-01

    Summary Pseudomonas aeruginosa is an important life-threatening nosocomial pathogen that plays a prominent role in wound infections of burned patients. We designed this study to identify the isolates of P. aeruginosa recovered from burned patients at the genus and species level through primers targeting oprI and oprL genes, and analyzed their antimicrobial resistance pattern. Over a 2-month period, wound samples were taken from burned patients and plated on MacConkey agar. All suspected colonies were primarily screened for P. aeruginosa by a combination of phenotypic tests. Molecular identifications of colonies were done using specific primers for oprI and oprL genes. Bacterial isolates were recovered from burn wound infections. Based on phenotypical identification tests, 138 (34%) P. aeruginosa isolates were identified; whereas by molecular techniques, just 128 P. aeruginosa yielded amplicon of oprL gene using species-specific primers, verifying the identity of P. aeruginosa; the others yielded amplicon of oprI gene using genus-specific primers, confirming the identity of fluorescent pseudomonads. This study indicates that molecular detection of P. aeruginosa in burn patients employing the OprL gene target is a useful technique for the early and precise detection of P. aeruginosa. PCR detection should be carried out as well as phenotypic testing for the best aggressive antibiotic treatment of P. aeruginosa strains at an earlier stage. It also has significant benefits on clinical outcomes. PMID:28289359

  13. Prevalence of resistance to aminoglycosides and fluoroquinolones among Pseudomonas aeruginosa strains in a University Hospital in Northeastern Poland.

    PubMed

    Michalska, Anna Diana; Sacha, Pawel Tomasz; Ojdana, Dominika; Wieczorek, Anna; Tryniszewska, Elzbieta

    2014-01-01

    The present study was conducted to investigate the prevalence of genes encoding resistance to aminoglycosides and fluoroquinolones among twenty-five Pseudomonas aeruginosa isolated between 2002 and 2009. In PCR, following genes were detected: ant(2″)-Ia in 9 (36.0%), aac(6')-Ib in 7 (28.0%), qnrB in 5 (20.0%), aph(3″)-Ib in 2 (8.0%) of isolates.

  14. 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.

  15. 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

  16. Staphylococcus aureus and Pseudomonas aeruginosa co-infection is associated with cystic fibrosis-related diabetes and poor clinical outcomes.

    PubMed

    Limoli, D H; Yang, J; Khansaheb, M K; Helfman, B; Peng, L; Stecenko, A A; Goldberg, J B

    2016-06-01

    Cystic fibrosis-related diabetes (CFRD) patients suffer from accelerated rates of pulmonary decline compared to cystic fibrosis (CF) patients with normal glucose tolerance (NGT). However, the mechanisms underlying this difference are unknown. While CFRD is associated with increased respiratory infections, a link between infection and enhanced pulmonary dysfunction remains unclear. The development of glucose intolerance is spectral, resulting in impaired glucose tolerance (IGT) prior to the diagnosis of CFRD. Inclusion of IGT patients within the NGT group may diminish the ability to identify correlations with CFRD. With this in mind, this study aimed to determine if the association between CFRD and respiratory infections is correlated with pulmonary decline. Respiratory cultures from 234 CF patients with confirmed diagnosis of NGT or CFRD were analyzed to measure rates of infection, focusing on the two most prevalent bacteria in CF, Staphylococcus aureus and Pseudomonas aeruginosa. Infection status was correlated with pulmonary function and confounding clinical variables including age, gender, blood glucose levels, and CF transmembrane conductance regulator (CFTR) phenotype were considered in multivariate analyses. CFRD patients, particularly those with extremely high blood glucose levels, were more likely than NGT patients to be co-infected with S. aureus and P. aeruginosa, compared to infection with only one pathogen. Co-infection was associated with decreased lung function and increased frequency of pulmonary exacerbations, even after adjustment for confounding variables. Alterations in the microbial community composition, as opposed to the presence of a single pathogen, may account for greater pulmonary decline in CFRD patients.

  17. Quinazoline derivatives are efficient chemosensitizers of antibiotic activity in Enterobacter aerogenes, Klebsiella pneumoniae and Pseudomonas aeruginosa resistant strains.

    PubMed

    Chevalier, Jacqueline; Mahamoud, Abdallah; Baitiche, Milad; Adam, Elissavet; Viveiros, Miguel; Smarandache, Adriana; Militaru, Andra; Pascu, Mihail L; Amaral, Leonard; Pagès, Jean-Marie

    2010-08-01

    Amongst the three series of quinazoline derivatives synthesised and studied in this work, some molecules increase the antibiotic susceptibility of Gram-negative bacteria presenting multidrug-resistant phenotypes. N-alkyl compounds induced an increase in the activity of chloramphenicol, nalidixic acid and sparfloxacin, which are substrates of the AcrAB-TolC and MexAB-OprM efflux pumps in clinical isolates. These molecules are able to increase the intracellular concentration of chloramphenicol in efflux pump-overproducing strains. Their activity depends on the antibiotic structure, suggesting that different sites may be involved for the recognition of substrates by a given efflux pump. Quinazoline molecules exhibiting a nitro functional group are more active, and structure-activity relationship studies may be undertaken to identify the pharmacophoric group involved in the AcrB and MexB affinity sites.

  18. Bacteriophages of Pseudomonas aeruginosa: long-term prospects for use in phage therapy.

    PubMed

    Krylov, Victor N

    2014-01-01

    Bacteria Pseudomonas aeruginosa, being opportunistic pathogens, are the major cause of nosocomial infections and, in some cases, the primary cause of death. They are virtually untreatable with currently known antibiotics. Phage therapy is considered as one of the possible approaches to the treatment of P. aeruginosa infections. Difficulties in the implementation of phage therapy in medical practice are related, for example, to the insufficient number and diversity of virulent phages that are active against P. aeruginosa. Results of interaction of therapeutic phages with bacteria in different conditions and environments are studied insufficiently. A little is known about possible interactions of therapeutic phages with resident prophages and plasmids in clinical strains in the foci of infections. This chapter highlights the different approaches to solving these problems and possible ways to expand the diversity of therapeutic P. aeruginosa phages and organizational arrangements (as banks of phages) to ensure long-term use of phages in the treatment of P. aeruginosa infections.

  19. Mutational and acquired carbapenem resistance mechanisms in multidrug resistant Pseudomonas aeruginosa clinical isolates from Recife, Brazil.

    PubMed

    Cavalcanti, Felipe Lira de Sá; Mirones, Cristina Rodríguez; Paucar, Elena Román; Montes, Laura Álvarez; Leal-Balbino, Tereza Cristina; Morais, Marcia Maria Camargo de; Martínez-Martínez, Luis; Ocampo-Sosa, Alain Antonio

    2015-12-01

    An investigation was carried out into the genetic mechanisms responsible for multidrug resistance in nine carbapenem-resistant Pseudomonas aeruginosa isolates from different hospitals in Recife, Brazil. Susceptibility to antimicrobial agents was determined by broth microdilution. Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding β-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases, integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The blaSPM-1, blaKPC-2 and blaGES-1 genes were detected in P. aeruginosa isolates in addition to different AME genes. The loss of OprD in nine isolates was mainly due to frameshift mutations, premature stop codons and point mutations. An association of loss of OprD with the overexpression of MexAB-OprM and MexXY-OprM was observed in most isolates. Hyper-production of AmpC was also observed in three isolates. Clonal relationship of the isolates was determined by repetitive element palindromic-PCR and multilocus sequence typing. Our results show that the loss of OprD along with overexpression of efflux pumps and β-lactamase production were responsible for the multidrug resistance in the isolates analysed.

  20. [Biochemical differentiation of proteus strains from various clinical materials].

    PubMed

    Józefowicz-Piatkowska, H; Woch, G

    1993-01-01

    The material consisted of 729 strain of Proteus isolated from clinical samples in three microbiological laboratories of city of Lódź region. Our of these strains, 466 were Proteus mirabilis, and remaining represented: P. penneri-13 strains, P. vulgaris (II biogroup)-56 and 54 strains which were not classifiable on the basis of biochemical properties and scheme elaborated by Hickman et al. for biogroups of P. vulgaris. The authors indicate feasibility of differentiation of P. vulgaris basing on biochemical tests as a supplementary method to other tests of intracellular differentiation of Proteus.

  1. Auxotrophic variants of Pseudomonas aeruginosa are selected from prototrophic wild-type strains in respiratory infections in patients with cystic fibrosis.

    PubMed Central

    Barth, A L; Pitt, T L

    1995-01-01

    Twenty-four nutritionally dependent (auxotrophic) Pseudomonas aeruginosa strains were isolated from 20 cystic fibrosis (CF) patients and tested for their amino acid requirements. Two different methods were necessary to identify the nutritional status of all isolates. Methionine was the most common single amino acid required (9 of 24 isolates), followed by leucine and arginine or ornithine. In total, a requirement for 12 different compounds or combination of compounds was demonstrated. Auxotrophic and prototrophic pairs of isolates from the same patient were compared by macrorestriction analysis of DNA in pulsed-field gel electrophoresis. Thirteen of 18 pairs analyzed presented identical restriction fragment length polymorphism profiles following digestion of DNA with XbaI. Three of the remaining pairs showed percentage similarities of 77, 91, and 98%, and the profiles of two pairs could not be compared because of the excessive degradation of their DNA. These results suggest that auxotrophic and prototrophic P. aeruginosa isolates colonizing the same CF patient constitute an isogenic group and raise the possibility that auxotrophs are selected from the prototrophic population during the course of pulmonary infection in CF patients. PMID:7699062

  2. Modulation of antibiotic resistance in Pseudomonas aeruginosa by ZnO nanoparticles

    PubMed Central

    Bayroodi, Elnaz; Jalal, Razieh

    2016-01-01

    Background and Objectives: Bacterial resistance to conventional antibiotics has become a widespread public health problem. The aim of this study was to investigate the influence of zinc oxide nanoparticles (ZnO NPs) on the antibacterial activity of several conventional antibiotics against Pseudomonas aeruginosa. Materials and Methods: ZnO NPs were prepared by solvothermal method and dispersed in glycerol with the help of ammonium citrate as a dispersant. The antibacterial effects of the resulting ZnO nanofluid, ceftazidime, tobramycin, and ciprofloxacin were investigated against two P. aeruginosa strains, including one clinical isolate and P. aeruginosa ATCC 9027 using microdilution method. For the evaluation of the combined effect of ZnO nanofluid and antibiotics, the fractional inhibitory concentration indices were calculated and isobolograms were plotted. Results: Clinical strain in comparison to standard strain of P. aeruginosa showed more resistance to ZnO nanofluid and the antibiotics. ZnO nanofluid acted synergistically with ceftazidime and tobramycin against both strains. Combination of ZnO nanofluid and ciprofloxacin displayed synergistic and partial synergistic activity against clinical and standard strains of P. aeruginosa, respectively. Conclusion: The results suggest that bacterial resistance to antimicrobials could be reduced by the synergistic action of ZnO NPs. PMID:27307973

  3. SERS detection of the biomarker hydrogen cyanide from Pseudomonas aeruginosa cultures isolated from cystic fibrosis patients

    PubMed Central

    Lauridsen, Rikke Kragh; Sommer, Lea M.; Johansen, Helle Krogh; Rindzevicius, Tomas; Molin, Søren; Jelsbak, Lars; Engelsen, Søren Balling; Boisen, Anja

    2017-01-01

    Pseudomonas aeruginosa is the primary cause of chronic airway infections in cystic fibrosis (CF) patients. Persistent infections are seen from the first P. aeruginosa culture in about 75% of young CF patients, and it is important to discover new ways to detect P. aeruginosa at an earlier stage. The P. aeruginosa biomarker hydrogen cyanide (HCN) contains a triple bond, which is utilized in this study because of the resulting characteristic C≡N peak at 2135 cm−1 in a Raman spectrum. The Raman signal was enhanced by surface-enhanced Raman spectroscopy (SERS) on a Au-coated SERS substrate. After long-term infection, a mutation in the patho-adaptive lasR gene can alter the expression of HCN, which is why it is sometimes not possible to detect HCN in the breath of chronically infected patients. Four P. aeruginosa reference strains and 12 clinical P. aeruginosa strains isolated from CF children were evaluated, and HCN was clearly detected from overnight cultures of all wild type-like isolates and half of the later isolates from the same patients. The clinical impact could be that P. aeruginosa infections could be detected at an earlier stage, because daily breath sampling with an immediate output could be possible with a point-of-care SERS device. PMID:28349938

  4. Aminoglycoside resistance patterns of Serratia marcescens strains of clinical origin.

    PubMed

    Coria-Jiménez, R; Ortiz-Torres, C

    1994-02-01

    Aminoglycoside resistance patterns of 147 Serratia marcescens strains of clinical origin were studied. All strains analysed belonged to three different bacterial populations. The periods of study and the institutions the strains were isolated from correlated significantly with the resistance patterns shown by the strains. The most frequent resistance patterns found were the following: ACC (6')-I at the Hospital Infantil de México (Children's Hospital of México), and ANT (2'') + AAC(6')-I at the Instituto Nacional de Pediatría (INPed or National Institute of Pediatrics) in Mexico City. Furthermore, the isolation frequency of aminoglycoside-sensitive strains decreased remarkably at the INPed over a 12-year period. These results suggest that there has been a selection of Serratia marcescens strains that are very resistant to aminoglycosides.

  5. Plasmid Profile Analysis and bla VIM Gene Detection of Metalo β-lactamase (MBL) Producing Pseudomonas aeruginosa Isolates from Clinical Samples

    PubMed Central

    M, Jeya

    2014-01-01

    Introduction:Pseudomonas aeruginosa is a frequent colonizer of hospitalized patients. They are responsible for serious infections such as meningitis, urological infections, septicemia and pneumonia. Carbapenem resistance of Pseudomonas aeruginosa is currently increasingly reported which is often mediated by production of metallo-β-lactamase (MBL). Multidrug resistant Pseudomonas aeruginosa isolates may involve reduced cell wall permeability, production of chromosomal and plasmid mediated β lactamases, aminoglycosides modifying enzymes and an active multidrug efflux mechanism. Objective: This study is aimed to detect the presence and the nature of plasmids among metallo-β-lactamase producing Pseudomonas aeruginosa isolates. Also to detect the presence of bla VIM gene from these isolates. Materials and Methods: Clinical isolates of Pseudomonas aeruginosa showing the metalo-β-lactamase enzyme (MBL) production were isolated. The MBL production was confirmed by three different methods. From the MBL producing isolates plasmid extraction was done by alkaline lysis method. Plasmid positive isolates were subjected for blaVIM gene detection by PCR method. Results: Two thousand seventy six clinical samples yielded 316 (15.22%) Pseudomonas aeruginosa isolates, out of which 141 (44.62%) were multidrug resistant. Among them 25 (17.73%) were metallo-β-lactamase enzyme producers. Plasmids were extracted from 18 out of 25 isolates tested. Five out of 18 isolates were positive for the blaVIM gene detection by the PCR amplification. Conclusion: The MBL producers were susceptible to polymyxin /colistin with MIC ranging from 0.5 – 2μg/ml. Molecular detection of specific genes bla VIM were positive among the carbapenem resistant isolates. PMID:25120980

  6. Antimicrobial activity of honey of stingless bees, tiúba (Melipona fasciculata) and jandaira (Melipona subnitida) compared to the strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa

    NASA Astrophysics Data System (ADS)

    Tenório, Eleuza Gomes; de Jesus, Natália Rocha; Nascimento, Adenilde Ribeiro; Teles, Amanda Mara

    2015-12-01

    This study aimed to investigate the antimicrobial activity of honeys of stingless bees produced in Maranhão, tiúba (Melipona fasciculata) and jandaira (Melipona subnitida), opposite the strains of pathogenic bacteria, namely, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The honey samples were collected from different regions of Maranhão. Of the 17 samples collected, twelve samples were honey M. fasciculata and five were honey M. subnitida. We used the Kirby-Bauer method, and the technique of agar disk diffusion through the extent of inhibition in milimetros. Results were negative for all samples from M. fasciculata. However, the tests for M. subnitida demonstrated bacteriostatic halos ranging from 12 to 32,6mm.

  7. Detection of extended spectrum beta lactamases, ampc beta lactamases and metallobetalactamases in clinical isolates of ceftazidime resistant Pseudomonas Aeruginosa.

    PubMed

    Umadevi, Sivaraman; Joseph, Noyal M; Kumari, Kandha; Easow, Joshy M; Kumar, Shailesh; Stephen, Selvaraj; Srirangaraj, Sreenivasan; Raj, Sruthi

    2011-10-01

    We studied the prevalence of ceftazidime resistance in Pseudomonas aeruginosa and the rates of extended-spectrum β-lactamase (ESBL), AmpC β-lactamase (AmpC) and metallo-β-lactamase (MBL) production among the ceftazidime resistant Pseudomonas aeruginosa. A very high rate of MBL production was observed, which suggested it to be an important contributing factor for ceftazidime resistance among Pseudomonas aeruginosa.

  8. 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.

  9. 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

  10. Molecular Epidemiology of sil Locus in Clinical Streptococcus pyogenes Strains

    PubMed Central

    Plainvert, Céline; Dinis, Márcia; Ravins, Miriam; Hanski, Emanuel; Touak, Gérald; Dmytruk, Nicolas; Fouet, Agnès

    2014-01-01

    Streptococcus pyogenes (group A Streptococcus [GAS]) causes a wide variety of diseases, ranging from mild noninvasive to severe invasive infections. Mutations in regulatory components have been implicated in the switch from colonization to invasive phenotypes. The inactivation of the sil locus, composed of six genes encoding a quorum-sensing complex, gives rise to a highly invasive strain. However, studies conducted on limited collections of GAS strains suggested that sil prevalence is around 15%; furthermore, whereas a correlation between the presence of sil and the genetic background was suggested, no link between the presence of a functional sil locus and the invasive status was assessed. We established a collection of 637 nonredundant strains covering all emm genotypes present in France and of known clinical history; 68%, 22%, and 10% were from invasive infections, noninvasive infections, and asymptomatic carriage, respectively. Among the 637 strains, 206 were sil positive. The prevalence of the sil locus varied according to the emm genotype, being present in >85% of the emm4, emm18, emm32, emm60, emm87, and emm90 strains and absent from all emm1, emm28, and emm89 strains. A random selection based on 2009 French epidemiological data indicated that 16% of GAS strains are sil positive. Moreover, due to mutations leading to truncated proteins, only 9% of GAS strains harbor a predicted functional sil system. No correlation was observed between the presence or absence of a functional sil locus and the strain invasiveness status. PMID:24671796

  11. Genome-Wide Transcription Study of Cryptococcus neoformans H99 Clinical Strain versus Environmental Strains.

    PubMed

    Movahed, Elaheh; Munusamy, Komathy; Tan, Grace Min Yi; Looi, Chung Yeng; Tay, Sun Tee; Wong, Won Fen

    2015-01-01

    The infection of Cryptococcus neoformans is acquired through the inhalation of desiccated yeast cells and basidiospores originated from the environment, particularly from bird's droppings and decaying wood. Three environmental strains of C. neoformans originated from bird droppings (H4, S48B and S68B) and C. neoformans reference clinical strain (H99) were used for intranasal infection in C57BL/6 mice. We showed that the H99 strain demonstrated higher virulence compared to H4, S48B and S68B strains. To examine if gene expression contributed to the different degree of virulence among these strains, a genome-wide microarray study was performed to inspect the transcriptomic profiles of all four strains. Our results revealed that out of 7,419 genes (22,257 probes) examined, 65 genes were significantly up-or down-regulated in H99 versus H4, S48B and S68B strains. The up-regulated genes in H99 strain include Hydroxymethylglutaryl-CoA synthase (MVA1), Mitochondrial matrix factor 1 (MMF1), Bud-site-selection protein 8 (BUD8), High affinity glucose transporter 3 (SNF3) and Rho GTPase-activating protein 2 (RGA2). Pathway annotation using DAVID bioinformatics resource showed that metal ion binding and sugar transmembrane transporter activity pathways were highly expressed in the H99 strain. We suggest that the genes and pathways identified may possibly play crucial roles in the fungal pathogenesis.

  12. Genome-Wide Transcription Study of Cryptococcus neoformans H99 Clinical Strain versus Environmental Strains

    PubMed Central

    Movahed, Elaheh; Munusamy, Komathy; Tan, Grace Min Yi; Looi, Chung Yeng; Tay, Sun Tee; Wong, Won Fen

    2015-01-01

    The infection of Cryptococcus neoformans is acquired through the inhalation of desiccated yeast cells and basidiospores originated from the environment, particularly from bird’s droppings and decaying wood. Three environmental strains of C. neoformans originated from bird droppings (H4, S48B and S68B) and C. neoformans reference clinical strain (H99) were used for intranasal infection in C57BL/6 mice. We showed that the H99 strain demonstrated higher virulence compared to H4, S48B and S68B strains. To examine if gene expression contributed to the different degree of virulence among these strains, a genome-wide microarray study was performed to inspect the transcriptomic profiles of all four strains. Our results revealed that out of 7,419 genes (22,257 probes) examined, 65 genes were significantly up-or down-regulated in H99 versus H4, S48B and S68B strains. The up-regulated genes in H99 strain include Hydroxymethylglutaryl-CoA synthase (MVA1), Mitochondrial matrix factor 1 (MMF1), Bud-site-selection protein 8 (BUD8), High affinity glucose transporter 3 (SNF3) and Rho GTPase-activating protein 2 (RGA2). Pathway annotation using DAVID bioinformatics resource showed that metal ion binding and sugar transmembrane transporter activity pathways were highly expressed in the H99 strain. We suggest that the genes and pathways identified may possibly play crucial roles in the fungal pathogenesis. PMID:26360021

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

    PubMed Central

    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.

    2016-01-01

    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

  14. Evaluation of flagella and flagellin of Pseudomonas aeruginosa as vaccines.

    PubMed

    Campodónico, Victoria L; Llosa, Nicolás J; Grout, Martha; Döring, Gerd; Maira-Litrán, Tomás; Pier, Gerald B

    2010-02-01

    Pseudomonas aeruginosa is a serious pathogen in hospitalized, immunocompromised, and cystic fibrosis (CF) patients. P. aeruginosa is motile via a single polar flagellum made of polymerized flagellin proteins differentiated into two major serotypes: a and b. Antibodies to flagella delay onset of infection in CF patients, but whether immunity to polymeric flagella and that to monomeric flagellin are comparable has not been addressed, nor has the question of whether such antibodies might negatively impact Toll-like receptor 5 (TLR5) activation, an important component of innate immunity to P. aeruginosa. We compared immunization with flagella and that with flagellin for in vitro effects on motility, opsonic killing, and protective efficacy using a mouse pneumonia model. Antibodies to flagella were superior to antibodies to flagellin at inhibiting motility, promoting opsonic killing, and mediating protection against P. aeruginosa pneumonia in mice. Protection against the flagellar type strains PAK and PA01 was maximal, but it was only marginal against motile clinical isolates from flagellum-immunized CF patients who nonetheless became colonized with P. aeruginosa. Purified flagellin was a more potent activator of TLR5 than were flagella and also elicited higher TLR5-neutralizing antibodies than did immunization with flagella. Antibody to type a but not type b flagella or flagellin inhibited TLR5 activation by whole bacterial cells. Overall, intact flagella appear to be superior for generating immunity to P. aeruginosa, and flagellin monomers might induce antibodies capable of neutralizing innate immunity due to TLR5 activation, but solid immunity to P. aeruginosa based on flagellar antigens may require additional components beyond type a and type b proteins from prototype strains.

  15. Comparative genetic characterization of Enteroaggregative Escherichia coli strains recovered from clinical and non-clinical settings

    PubMed Central

    Zhang, Rong; Gu, Dan-xia; Huang, Yong-lu; Chan, Edward Wai-Chi; Chen, Gong-Xiang; Chen, Sheng

    2016-01-01

    The origin of pathogenic Enteroaggregative Escherichia coli (EAEC), a major causative agent of childhood diarrhea worldwide, remains ill-defined. The objective of this study was to determine the relative prevalence of EAEC in clinical and non-clinical sources and compare their genetic characteristics in order to identify strains that rarely and commonly cause human diarrhea. The virulence gene astA was commonly detectable in both clinical and non-clinical EAEC, while clinical isolates, but not the non-clinical strains, were consistently found to harbor other virulence factors such as aap (32%), aatA (18%) and aggR (11%). MLST analysis revealed the extremely high diversity of EAEC ST types, which can be grouped into three categories including: (i) non-clinical EAEC that rarely cause human infections; (ii) virulent strains recoverable in diarrhea patients that are also commonly found in the non-clinical sources; (iii) organisms causing human infections but rarely recoverable in the non-clinical setting. In addition, the high resistance in these EAEC isolates in particular resistance to fluoroquinolones and cephalosporins raised a huge concern for clinical EAEC infection control. The data from this study suggests that EAEC strains were diversely distributed in non-clinical and clinical setting and some of the clinical isolates may originate from the non-clinical setting. PMID:27062991

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

    PubMed Central

    Çevik, Kübra; Ulusoy, Seyhan

    2015-01-01

    Objective(s): The inhibitory effects of iron chelators, and FeCl3 chelation on biofilm formation and swarming motility were investigated against an opportunistic human pathogen Pseudomonas aeruginosa. Materials and Methods: The inhibitory activity of 2,2’-bipyridyl, lipoic acid, kojic acid and picolinic acid on biofilm formation of P. aeruginosa strain PAO1 and three clinical isolates (P. aeruginosa PAK01, P. aeruginosa PAK02 and P. aeruginosa PAK03) were investigated, based on crystal violet assay, and swarming motility test. Results: The kojic, lipoic and picolinic acid inhibited biofilm formation by 5-33% in all tested P. aeruginosa isolates. When chelated iron was added, biofilm inhibition rates were determined to be 39-57%. Among the tested chelators against P. aeruginosa, lipoic acid (84%) and kojic acid (68%) presented the highest inhibition of swarming motility. This is the first study to report the inhibitory effect of lipoic acid on biofilm formation and swarming motility of P. aeruginosa. Conclusion: It is considered that lipoic and picolinic acids can serve as alternatives for the treatment of the P. aeruginosa infections by inhibiting biofilm formation. PMID:26557964

  17. Temperature-dependent sensitivity of growth and photosynthesis of Scenedesmus obliquus, Navicula pelliculosa and two strains of Microcystis aeruginosa to the herbicide atrazine.

    PubMed

    Chalifour, Annie; Juneau, Philippe

    2011-05-01

    The temperature-dependent sensitivities of two algal species and two strains of cyanobacteria to the photosynthesis-inhibiting herbicide atrazine were evaluated in order to understand how the interaction between acclimation temperature and herbicide will affect growth and photosynthesis of aquatic microorganisms. The green alga Scenedesmus obliquus, the diatom Navicula pelliculosa and a toxic and non-toxic strain of Microcystis aeruginosa were acclimated to three different temperatures (10, 15 and 25°C) and exposed to five concentrations of the herbicide atrazine (0-0.15μM) for 72h. Growth, photosynthetic yields, energy fluxes within photosystem II and pigment content were then measured as potential responses to each treatment. With the exception of N. pelliculosa, the toxicity of atrazine was higher when microorganisms were acclimated to lower temperatures. N. pelliculosa was not only the most tolerant to atrazine, but also had a similar sensitivity to this herbicide at every temperature. The observed differences in growth sensitivity to atrazine at low temperature are associated with the ability of algae and cyanobacteria to cope with high excitation pressure, by increasing its protective carotenoid content and non-photochemical energy dissipation. Our results demonstrate that future guidelines for the protection of aquatic life should consider water temperature as an important factor influencing the toxicity of atrazine to aquatic microorganisms.

  18. Evaluation of Stress-Induced Microbial Siderophore from Pseudomonas aeruginosa Strain S1 as a Potential Matrix Metalloproteinase Inhibitor in Wound Healing Applications.

    PubMed

    Thyagarajan, Sita Lakshmi; Kandhasamy, S; Ramanathan, Giriprasath; Sivagnanam, Uma Tiruchirapalli; Perumal, P T

    2016-05-01

    Matrix metalloproteinases (MMPs) are zinc-dependent proteolytic enzymes capable of causing various inflammatory and various degenerative diseases if over-expressed. The active site of these enzymes is a zinc binding motif which binds to the specific site on the substrate and induce degradation. Hence an inhibitor is required to form a complex with zinc motif which hampers the binding ability of MMPs. To obtain novel MMPs inhibitor for wound healing, the chelating activity of siderophore from the microbial source was focused. During screening for siderophore production, strain S1 produced the highest amount of siderophore in the minimal salts medium. The isolate was confirmed as Pseudomonas aeruginosa strain S1 based on 16S rRNA gene sequencing and phylogenetic analysis. The activity of the siderophore was assayed using chrome azurol sulphonate and purified by the chromatographic techniques. The structural evidence through Fourier transform infrared and nuclear magnetic resonance spectra revealed that the isolated siderophore is a catecholate type with the distinctive characters. The positive results of calcein and fluozin-3 assays indicate that siderophore could bind to divalent metal ions, namely Fe(2+) and Zn(2+). As the siderophore compound focused on wound healing property, the in vitro studies revealed the viability of NH3T3 fibroblast cells and its efficiency in matrix modulating was confirmed through gelatin zymogram.

  19. Characteristics of clinical Helicobacter pylori strains from Ecuador.

    PubMed

    Debets-Ossenkopp, Yvette J; Reyes, Germán; Mulder, Janet; aan de Stegge, Birgit M; Peters, José T A M; Savelkoul, Paul H M; Tanca, J; Peña, Amado S; Vandenbroucke-Grauls, Christina M J E

    2003-01-01

    In Ecuador, Helicobacter pylori infections are highly prevalent. A total of 42 H. pylori clinical isolates from 86 patients attending the outpatient clinic of the gastroenterology department of the university hospital of Guayaquil in Ecuador were characterized. Their susceptibility, and cagA and vacA status were determined. Resistance to metronidazole and clarithromycin was found in 80.9% and 9.5% of strains, respectively. Neither amoxicillin- nor tetracycline-resistant strains were found. The most prevalent genotype was the cagA(+), vacA s1b,m1 type. This genotype was associated with gastric cancer and peptic ulcer. Typing by random amplified polymorphic DNA showed no genetic relationship among the strains.

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

    PubMed Central

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

    2016-01-01

    Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) colonize cystic fibrosis (CF) patient airways. Pa culture filtrates inhibit Af biofilms, and Pa non-CF, mucoid (Muc-CF) and nonmucoid CF (NMuc-CF) isolates form an ascending inhibitory hierarchy. We hypothesized this activity is mediated through apoptosis induction. One Af and three Pa (non-CF, Muc-CF, NMuc-CF) reference isolates were studied. Af biofilm was formed in 96 well plates for 16 h ± Pa biofilm filtrates. After 24 h, apoptosis was characterized by viability dye DiBAc, reactive oxygen species (ROS) generation, mitochondrial membrane depolarization, DNA fragmentation and metacaspase activity. Muc-CF and NMuc-CF filtrates inhibited and damaged Af biofilm (p<0.0001). Intracellular ROS levels were elevated (p<0.001) in NMuc-CF-treated Af biofilms (3.7- fold) compared to treatment with filtrates from Muc-CF- (2.5- fold) or non-CF Pa (1.7- fold). Depolarization of mitochondrial potential was greater upon exposure to NMuc-CF (2.4-fold) compared to Muc-CF (1.8-fold) or non-CF (1.25-fold) (p<0.0001) filtrates. Exposure to filtrates resulted in more DNA fragmentation in Af biofilm, compared to control, mediated by metacaspase activation. In conclusion, filtrates from CF-Pa isolates were more inhibitory against Af biofilms than from non-CF. The apoptotic effect involves mitochondrial membrane damage associated with metacaspase activation. PMID:26930399

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

    PubMed

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

    2016-01-01

    Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) colonize cystic fibrosis (CF) patient airways. Pa culture filtrates inhibit Af biofilms, and Pa non-CF, mucoid (Muc-CF) and nonmucoid CF (NMuc-CF) isolates form an ascending inhibitory hierarchy. We hypothesized this activity is mediated through apoptosis induction. One Af and three Pa (non-CF, Muc-CF, NMuc-CF) reference isolates were studied. Af biofilm was formed in 96 well plates for 16 h ± Pa biofilm filtrates. After 24 h, apoptosis was characterized by viability dye DiBAc, reactive oxygen species (ROS) generation, mitochondrial membrane depolarization, DNA fragmentation and metacaspase activity. Muc-CF and NMuc-CF filtrates inhibited and damaged Af biofilm (p<0.0001). Intracellular ROS levels were elevated (p<0.001) in NMuc-CF-treated Af biofilms (3.7- fold) compared to treatment with filtrates from Muc-CF- (2.5- fold) or non-CF Pa (1.7- fold). Depolarization of mitochondrial potential was greater upon exposure to NMuc-CF (2.4-fold) compared to Muc-CF (1.8-fold) or non-CF (1.25-fold) (p<0.0001) filtrates. Exposure to filtrates resulted in more DNA fragmentation in Af biofilm, compared to control, mediated by metacaspase activation. In conclusion, filtrates from CF-Pa isolates were more inhibitory against Af biofilms than from non-CF. The apoptotic effect involves mitochondrial membrane damage associated with metacaspase activation.

  2. Carbon spectrum utilization by an indigenous strain of Pseudomonas aeruginosa NCIM 5514: Production, characterization and surface active properties of biosurfactant.

    PubMed

    Varjani, Sunita J; Upasani, Vivek N

    2016-12-01

    The present research work was undertaken with a mandate to study carbon spectrum utilization and structural characterization of biosurfactant produced by indigenous Pseudomonas aeruginosa NCIM 5514, which showed unique properties to utilize a large number of carbon sources effectively for production of biosurfactant, although glucose was the best carbon substrate. In Bushnell-Hass medium supplemented with glucose (1%, w/v), 3.178±0.071g/l biosurfactant was produced by this isolate in 96h. The biosurfactant produced showed surface tension and emulsification activity values from 29.14±0.05 to 62.29±0.13mN/m and 88.50±1.96 to 15.40±0.91%, respectively. Toluene showed highest emulsification activity followed by kerosene. However, kerosene exhibited emulsion stability for 30days. Biosurfactant was characterized as a mixture of di-rhamnolipid (Rha-Rha-C10-C14:1) and mono-rhamnolipid (Rha-C8-C10) by FTIR, ESI-MS and LC-MS techniques. High biosurfactant yield opens up doors for the isolate to find utility in various industries.

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

    PubMed Central

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

    2016-01-01

    ABSTRACT 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

  4. Identification and Characterization of a Chemical Compound that Inhibits Methionyl-tRNA Synthetase from Pseudomonas aeruginosa.

    PubMed

    Robles, Sara; Hu, Yanmei; Resto, Tahyra; Dean, Frank; Bullard, James M

    2017-03-30

    Pseudomonas aeruginosa is an opportunistic pathogen problematic in causing nosocomial infections and is highly susceptible to development of resistance to multiple antibiotics. The gene encoding methionyl-tRNA synthetase (MetRS) from P. aeruginosa was cloned and the resulting protein characterized. MetRS was kinetically evaluated and the KM for its three substrates, methionine, ATP and tRNAMet were determined to be 35, 515, and 29 μM, respectively. P. aeruginosa MetRS was used to screen two chemical compound libraries (1690) and a natural product compound was identified that inhibited the aminoacylation function. The compound inhibited P. aeruginosa MetRS with an IC50 of 70 μM. The minimum inhibitory concentration (MIC) of the compound was determined against nine clinically relevant bacterial strains, including efflux pump mutants and hypersensitive strains of P. aeruginosa and E. coli. The compound displayed broad spectrum anti-bacterial activity. The MIC against the hypersensitive strain of P. aeruginosa was 16 μg/ml. However, the compound was not effective against the wild-type and efflux pump mutant strains, indicating that efflux may not be responsible for the lack of activity against the wild-type strains. When tested in human cell cultures, the cytotoxicity concentration (CC50) was observed to be 30 μg/ml. The compound did not compete with methionine or ATP for binding MetRS, indicating that the mechanism of action of the compound likely occurs outside the active site of aminoacylation.

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

    PubMed

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

    2014-08-01

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

  6. d-Amino Acids Enhance the Activity of Antimicrobials against Biofilms of Clinical Wound Isolates of Staphylococcus aureus and Pseudomonas aeruginosa

    PubMed Central

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

    2014-01-01

    Within wounds, microorganisms predominantly exist as biofilms. Biofilms are associated with chronic infections and represent a tremendous clinical challenge. As antibiotics are often ineffective against biofilms, use of dispersal agents as adjunctive, topical therapies for the treatment of wound infections involving biofilms has gained interest. We evaluated in vitro the dispersive activity of d-amino acids (d-AAs) on biofilms from clinical wound isolates of Staphylococcus aureus and Pseudomonas aeruginosa; moreover, we determined whether combinations of d-AAs and antibiotics (clindamycin, cefazolin, oxacillin, rifampin, and vancomycin for S. aureus and amikacin, colistin, ciprofloxacin, imipenem, and ceftazidime for P. aeruginosa) enhance activity against biofilms. d-Met, d-Phe, and d-Trp at concentrations of ≥5 mM effectively dispersed preformed biofilms of S. aureus and P. aeruginosa clinical isolates, an effect that was enhanced when they were combined as an equimolar mixture (d-Met/d-Phe/d-Trp). When combined with d-AAs, the activity of rifampin was significantly enhanced against biofilms of clinical isolates of S. aureus, as indicated by a reduction in the minimum biofilm inhibitory concentration (MBIC) (from 32 to 8 μg/ml) and a >2-log reduction of viable biofilm bacteria compared to treatment with antibiotic alone. The addition of d-AAs was also observed to enhance the activity of colistin and ciprofloxacin against biofilms of P. aeruginosa, reducing the observed MBIC and the number of viable bacteria by >2 logs and 1 log at 64 and 32 μg/ml in contrast to antibiotics alone. These findings indicate that the biofilm dispersal activity of d-AAs may represent an effective strategy, in combination with antimicrobials, to release bacteria from biofilms, subsequently enhancing antimicrobial activity. PMID:24841260

  7. Metallo-β-Lactamase Gene blaIMP-15 in a Class 1 Integron, In95, from Pseudomonas aeruginosa Clinical Isolates from a Hospital in Mexico▿

    PubMed Central

    Garza-Ramos, U.; Morfin-Otero, R.; Sader, H. S.; Jones, R. N.; Hernández, E.; Rodriguez-Noriega, E.; Sanchez, A.; Carrillo, B.; Esparza-Ahumada, S.; Silva-Sanchez, J.

    2008-01-01

    During 2003, 40 carbapenem-resistant Pseudomonas aeruginosa clinical isolates collected in a Mexican tertiary-care hospital were screened for metallo-β-lactamase production. Thirteen isolates produced IMP-15, and 12 had a single pulsed-field gel electrophoresis pattern. The blaIMP-15 gene cassette was inserted in a plasmid-borne integron with a unique array of gene cassettes and was named In95. PMID:18490501

  8. Mechanisms of carbapenem resistance in endemic Pseudomonas aeruginosa isolates after an SPM-1 metallo-β-lactamase producing strain subsided in an intensive care unit of a teaching hospital in Brazil

    PubMed Central

    Cacci, Luciana Camila; Chuster, Stephanie Gomes; Martins, Natacha; do Carmo, Pâmella Rodrigues; Girão, Valéria Brígido de Carvalho; Nouér, Simone Aranha; de Freitas, Wania Vasconcelos; de Matos, Juliana Arruda; Magalhães, Ana Cristina de Gouveia; Ferreira, Adriana Lúcia Pires; Picão, Renata Cristina; Moreira, Beatriz Meurer

    2016-01-01

    Carbapenem-resistance mechanisms are a challenge in the treatment of Pseudomonas aeruginosa infections. We investigated changes in P. aeruginosa carbapenem-resistance determinants over a time period of eight years after the emergence of São Paulo metallo-β-lactamase in a university hospital in Rio de Janeiro, Brazil. Patients admitted to the intensive care unit (ICU) were screened for P. aeruginosa colonisation and followed for the occurrence of infections from April 2007 to April 2008. The ICU environment was also sampled. Isolates were typed using random amplified polymorphic DNA, pulsed-field gel electrophoresis and multilocus sequence typing. Antimicrobial susceptibility was determined by disk diffusion and E-test, production of carbapenemases by a modified-CarbaNP test and presence of carbapenemase-encoding genes by polymerase chain reaction. Non-carbapenemase resistance mechanisms studied included efflux and AmpC overexpression by PAβN and cloxacillin susceptibility enhancement, respectively, as well as oprD mutations. From 472 P. aeruginosa clinical isolates (93 patients) and 17 isolates from the ICU environment, high genotypic diversity and several international clones were observed; one environment isolate belonged to the blaSPM-1 P. aeruginosa epidemic genotype. Among isolates from infections, 10 (29%) were carbapenem resistant: none produced carbapenemases, three exhibited all non-carbapenemase mechanisms studied, six presented a combination of two mechanisms, and one exclusively displayed oprD mutations. Carbapenem-resistant P. aeruginosa displayed a polyclonal profile after the SPM-1 epidemic genotype declined. This phenomenon is connected with blaSPM-1 P. aeruginosa replaced by other carbapenem-resistant pathogens. PMID:27653359

  9. Mechanisms of carbapenem resistance in endemic Pseudomonas aeruginosa isolates after an SPM-1 metallo-β-lactamase producing strain subsided in an intensive care unit of a teaching hospital in Brazil.

    PubMed

    Cacci, Luciana Camila; Chuster, Stephanie Gomes; Martins, Natacha; Carmo, Pâmella Rodrigues do; Girão, Valéria Brígido de Carvalho; Nouér, Simone Aranha; Freitas, Wania Vasconcelos de; Matos, Juliana Arruda de; Magalhães, Ana Cristina de Gouveia; Ferreira, Adriana Lúcia Pires; Picão, Renata Cristina; Moreira, Beatriz Meurer

    2016-09-01

    Carbapenem-resistance mechanisms are a challenge in the treatment of Pseudomonas aeruginosa infections. We investigated changes in P. aeruginosa carbapenem-resistance determinants over a time period of eight years after the emergence of São Paulo metallo-β-lactamase in a university hospital in Rio de Janeiro, Brazil. Patients admitted to the intensive care unit (ICU) were screened for P. aeruginosa colonisation and followed for the occurrence of infections from April 2007 to April 2008. The ICU environment was also sampled. Isolates were typed using random amplified polymorphic DNA, pulsed-field gel electrophoresis and multilocus sequence typing. Antimicrobial susceptibility was determined by disk diffusion and E-test, production of carbapenemases by a modified-CarbaNP test and presence of carbapenemase-encoding genes by polymerase chain reaction. Non-carbapenemase resistance mechanisms studied included efflux and AmpC overexpression by PAβN and cloxacillin susceptibility enhancement, respectively, as well as oprD mutations. From 472 P. aeruginosa clinical isolates (93 patients) and 17 isolates from the ICU environment, high genotypic diversity and several international clones were observed; one environment isolate belonged to the blaSPM-1 P. aeruginosa epidemic genotype. Among isolates from infections, 10 (29%) were carbapenem resistant: none produced carbapenemases, three exhibited all non-carbapenemase mechanisms studied, six presented a combination of two mechanisms, and one exclusively displayed oprD mutations. Carbapenem-resistant P. aeruginosa displayed a polyclonal profile after the SPM-1 epidemic genotype declined. This phenomenon is connected with blaSPM-1 P. aeruginosa replaced by other carbapenem-resistant pathogens.

  10. Molecular detection of virulence genes as markers in Pseudomonas aeruginosa isolated from urinary tract infections.

    PubMed

    Sabharwal, Neha; Dhall, Shriya; Chhibber, Sanjay; Harjai, Kusum

    2014-01-01

    Catheter associated urinary tract infections by P. aeruginosa are related to variety of complications. Quorum sensing and related circuitry guard its virulence potential. Though P. aeruginosa accounts for an appreciable amount of virulence factors, this organism is highly unstable phenotypically. Thus, genotyping of clinical isolates of P. aeruginosa is of utmost importance for understanding the epidemiology of infection. This may contribute towards development of immunotherapeutic approaches against this multi drug resistant pathogen. Moreover, no epidemiological study has been reported yet on uroisolates of P. aeruginosa. Thus this study was planned to obtain information regarding presence, distribution and rate of occurrence of quorum sensing and some associated virulence genes at genetic level. The profiling of quorum sensing genes lasI, lasR, rhlI, rhlR and virulence genes like toxA, aprA, rhlAB, plcH, lasB and fliC of twelve strains of P. aeruginosa isolated from patients with UTIs was done by direct PCR. The results showed variable distribution of quorum sensing genes and virulence genes. Their percentage occurrence may be specifically associated with different levels of intrinsic virulence and pathogenicity in urinary tract. Such information can help in identifying these virulence genes as useful diagnostic markers for clinical P. aeruginosa strains isolated from UTIs.

  11. Friend or foe: genetic and functional characterization of plant endophytic Pseudomonas aeruginosa.

    PubMed

    Kumar, A; Munder, A; Aravind, R; Eapen, S J; Tümmler, B; Raaijmakers, J M

    2013-03-01

    Endophytic Pseudomonas aeruginosa strain BP35 was originally isolated from black pepper grown in the rain forest in Kerala, India. Strain PaBP35 was shown to provide significant protection to black pepper against infections by Phytophthora capsici and Radopholus similis. For registration and implementation in disease management programmes, several traits of PaBP35 were investigated including its endophytic behaviour, biocontrol activity, phylogeny and toxicity to mammals. The results showed that PaBP35 efficiently colonized black pepper shoots and displayed a typical spatiotemporal pattern in its endophytic movement with concomitant suppression of Phytophthora rot. Confocal laser scanning microscopy revealed high populations of PaBP35::gfp2 inside tomato plantlets, supporting its endophytic behaviour in other plant species. Polyphasic approaches to genotype PaBP35, including BOX-PCR, recN sequence analysis, multilocus sequence typing and comparative genome hybridization analysis, revealed its uniqueness among P. aeruginosa strains representing clinical habitats. However, like other P. aeruginosa strains, PaBP35 exhibited resistance to antibiotics, grew at 25-41°C and produced rhamnolipids and phenazines. PaBP35 displayed strong type II secretion effectors-mediated cytotoxicity on mammalian A549 cells. Coupled with pathogenicity in a murine airway infection model, we conclude that this plant endophytic strain is as virulent as clinical P. aeruginosa strains. Safety issues related to the selection of plant endophytic bacteria for crop protection are discussed.

  12. 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.

  13. Use of RSM modeling for optimizing decolorization of simulated textile wastewater by Pseudomonas aeruginosa strain ZM130 capable of simultaneous removal of reactive dyes and hexavalent chromium.

    PubMed

    Maqbool, Zahid; Hussain, Sabir; Ahmad, Tanvir; Nadeem, Habibullah; Imran, Muhammad; Khalid, Azeem; Abid, Muhammad; Martin-Laurent, Fabrice

    2016-06-01

    Remediation of colored wastewater loaded with dyes and metal ions is a matter of interest nowadays. In this study, 220 bacteria isolated from textile wastewater were tested for their potential to decolorize each of the four reactive dyes (reactive red-120, reactive black-5, reactive yellow-2, and reactive orange-16) in the presence of a mixture of four different heavy metals (Cr, Zn, Pb, Cd) commonly found in textile effluents. Among the tested bacteria, the isolate ZM130 was found to be the most efficient in decolorizing reactive dyes in the presence of the mixture of heavy metals and was identified as Pseudomonas aeruginosa strain ZM130 by 16S rRNA gene analysis. The strain ZM130 was highly effective in simultaneously removing hexavalent chromium (25 mg L(-1)) and the azo dyes (100 mg L(-1)) from the simulated wastewater even in the presence of other three heavy metals (Zn, Pb, Cd). Simultaneous removal of chromium and azo dyes ranged as 76.6-98.7 % and 51.9-91.1 %, respectively, after 180 h incubation. On the basis of quadratic polynomial equation and response surfaces given by the response surface methodology (RSM), optimal salt content, pH, carbon co-substrate content, and level of multi-metal mixtures for decolorization of reactive red-120 in a simulated textile wastewater by the strain ZM130 were predicted to be 19.8, 7.8, and 6.33 g L(-1) and a multi-metal mixture (Cr 13.10 mg L(-1), Pb 26.21 mg L(-1), Cd 13.10 mg L(-1), Zn 26.21 mg L(-1)), respectively. Moreover, the strain ZM130 also exhibited laccase and nicotinamide adenine dinucleotide (reduced)-dichlorophenolindophenol reductase (NADH-DCIP reductase) activity during the decolorization of reactive red-120. However, the laccase activity was found to be maximum in the presence of 300 mg L(-1) of the dye as compared to other concentrations. Hence, the isolation of this strain might serve as a potential bio-resource required for developing the strategies aiming at bioremediation of the

  14. Bactericidal and synergistic activity of moxalactam alone and in combination with gentamicin against Pseudomonas aeruginosa.

    PubMed Central

    Yu, P K; Edson, R S; Washington, J A; Hermans, P E

    1983-01-01

    The bactericidal activity of moxalactam, alone and in combination with gentamicin, was studied with macrobroth two-dimensional checkerboard and killing curve techniques against gentamicin-resistant and -susceptible strains of Pseudomonas aeruginosa. Moxalactam was bactericidal at concentrations equal to or at least two to four times its inhibitory concentrations. Synergy at clinically applicable concentrations of moxalactam and gentamicin occurred with 6 of 14 gentamicin-resistant strains and 4 of 4 gentamicin-susceptible strains by the checkerboard technique and with 7 of 14 gentamicin-resistant strains by the killing curve technique. Synergy between moxalactam and gentamicin against gentamicin-resistant strains of P. aeruginosa is unpredictable and strain- and method-dependent. PMID:6219619

  15. Gold-functionalized magnetic nanoparticles restrict growth of Pseudomonas aeruginosa.

    PubMed

    Niemirowicz, Katarzyna; Swiecicka, Izabela; Wilczewska, Agnieszka Z; Misztalewska, Iwona; Kalska-Szostko, Beata; Bienias, Kamil; Bucki, Robert; Car, Halina

    2014-01-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) and their derivatives (aminosilane and gold-coated) have been widely investigated in numerous medical applications, including their potential to act as antibacterial drug carriers that may penetrate into bacteria cells and biofilm mass. Pseudomonas aeruginosa is a frequent cause of infection in hospitalized patients, and significant numbers of currently isolated clinical strains are resistant to standard antibiotic therapy. Here we describe the impact of three types of SPIONs on the growth of P. aeruginosa during long-term bacterial culture. Their size, structure, and physicochemical properties were determined using transmission electron microscopy, X-ray diffraction analysis, and Fourier transform infrared spectroscopy. We observed significant inhibition of P. aeruginosa growth in bacterial cultures continued over 96 hours in the presence of gold-functionalized nanoparticles (Fe₃O₄@Au). At the 48-hour time point, growth of P. aeruginosa, as assessed by the number of colonies grown from treated samples, showed the highest inhibition (decreased by 40%). These data provide strong evidence that Fe₃O₄@Au can dramatically reduce growth of P. aeruginosa and provide a platform for further study of the antibacterial activity of this nanomaterial.

  16. Isolation of VIM-2-Producing Pseudomonas monteilii Clinical Strains Disseminated in a Tertiary Hospital in Northern Spain

    PubMed Central

    Guzmán-Gómez, Laura P.; Fernández-Martínez, Marta; Román, Elena; Rodríguez, Cristina; Marco, Francesc; Vila, Jordi; Martínez-Martínez, Luis

    2014-01-01

    We describe here the occurrence of blaVIM-2 in 10 carbapenem-resistant Pseudomonas monteilii strains isolated from different clinical samples from patients at the University Hospital Marqués de Valdecilla in northern Spain. All the blaVIM-2-harboring P. monteilii isolates possessed a class 1 integron, with the cassette array [intI1_blaVIM-2_aac(6′)-Ib_qacEΔ1_sul1]. Our results show the emergence of VIM-2-producing multidrug-resistant species other than Pseudomonas aeruginosa or Pseudomonas putida in a Spanish hospital. P. monteilii, although sporadically isolated, should also be considered an important metallo-β-lactamase (MBL) reservoir. PMID:25421471

  17. Computation of interactive effects and optimization of process parameters for alkaline lipase production by mutant strain of Pseudomonas aeruginosa using response surface methodology

    PubMed Central

    Bisht, Deepali; Yadav, Santosh Kumar; Darmwal, Nandan Singh

    2013-01-01

    Alkaline lipase production by mutant strain of Pseudomonas aeruginosa MTCC 10,055 was optimized in shake flask batch fermentation using response surface methodology. An empirical model was developed through Box-Behnken experimental design to describe the relationship among tested variables (pH, temperature, castor oil, starch and triton-X-100). The second-order quadratic model determined the optimum conditions as castor oil, 1.77 mL.L−1; starch, 15.0 g.L−1; triton-X-100, 0.93 mL.L−1; incubation temperature, 34.12 °C and pH 8.1 resulting into maximum alkaline lipase production (3142.57 U.mL−1). The quadratic model was in satisfactory adjustment with the experimental data as evidenced by a high coefficient of determination (R2) value (0.9987). The RSM facilitated the analysis and interpretation of experimental data to ascertain the optimum conditions of the variables for the process and recognized the contribution of individual variables to assess the response under optimal conditions. Hence Box-Behnken approach could fruitfully be applied for process optimization. PMID:24159311

  18. Co-Carriage of blaKPC-2 and blaNDM-1 in Clinical Isolates of Pseudomonas aeruginosa Associated with Hospital Infections from India.

    PubMed

    Paul, Deepjyoti; Dhar Chanda, Debadatta; Maurya, Anand Prakash; Mishra, Shweta; Chakravarty, Atanu; Sharma, Gauri Dutt; Bhattacharjee, Amitabha

    2015-01-01

    Global spread of KPC poses to be a serious threat complicating treatment options in hospital settings. The present study investigates the genetic environment of blaKPC-2 among clinical isolates of Pseudomonas aeruginosa from a tertiary referral hospital of India. The study isolates were collected from different wards and clinics of Silchar Medical College and Hospital, India, from 2012-2013. The presence of blaKPC was confirmed by genotypic characterization followed by sequencing. Cloning of the blaKPC-2 gene was performed and the genetic environment of this gene was characterized as well. Transferability of the resistance gene was determined by transformation assay and Southern hybridization. Additionally, restriction mapping was also carried out. Two isolates of P. aeruginosa were found to harbor blaKPC-2, were resistant towards aminoglycosides, quinolone and β-lactam-β-lactamase inhibitor combination. In both the isolates, the resistance determinant was associated with class 1 integron and horizontally transferable. Both the isolates were co-harboring blaNDM-1. The first detection of this integron mediated blaKPC-2 coexisting with blaNDM-1 in P. aeruginosa from India is worrisome, and further investigation is required to track the gene cassette mediated blaKPC-2 in terms of infection control and to prevent the spread of this gene in hospitals as well as in the community.

  19. Pseudomonas aeruginosa inhibits the growth of Scedosporium aurantiacum, an opportunistic fungal pathogen isolated from the lungs of cystic fibrosis patients

    PubMed Central

    Kaur, Jashanpreet; Pethani, Bhavin P.; Kumar, Sheemal; Kim, Minkyoung; Sunna, Anwar; Kautto, Liisa; Penesyan, Anahit; Paulsen, Ian T.; Nevalainen, Helena

    2015-01-01

    The filamentous fungus Scedosporium aurantiacum and the bacterium Pseudomonas aeruginosa are opportunistic pathogens isolated from lungs of the cystic fibrosis (CF) patients. P. aeruginosa has been known to suppress the growth of a number of CF related fungi such as Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans. However, the interactions between P. aeruginosa and S. aurantiacum have not been investigated in depth. Hence we assessed the effect of P. aeruginosa reference strain PAO1 and two clinical isolates PASS1 and PASS2 on the growth of two clinical S. aurantiacum isolates WM 06.482 and WM 08.202 using solid plate assays and liquid cultures, in a synthetic medium mimicking the nutrient condition in the CF sputum. Solid plate assays showed a clear inhibition of growth of both S. aurantiacum strains when cultured with P. aeruginosa strains PASS1 and PAO1. The inhibitory effect was confirmed by confocal microscopy. In addition to using chemical fluorescent stains, strains tagged with yfp (P. aeruginosa PASS1) and mCherry (S. aurantiacum WM 06.482) were created to facilitate detailed microscopic observations on strain interaction. To our knowledge, this is the first study describing successful genetic transformation of S. aurantiacum. Inhibition of growth was observed only in co-cultures of P. aeruginosa and S. aurantiacum; the cell fractions obtained from independent bacterial monocultures failed to initiate a response against the fungus. In the liquid co-cultures, biofilm forming P. aeruginosa strains PASS1 and PAO1 displayed higher inhibition of fungal growth when compared to PASS2. No change was observed in the inhibition pattern when direct cell contact between the bacterial and fungal strains was prevented using a separation membrane suggesting the involvement of extracellular metabolites in the fungal inhibition. However, one of the most commonly described bacterial virulence factors, pyocyanin, had no effect against either of the S

  20. Pseudomonas aeruginosa inhibits the growth of Scedosporium aurantiacum, an opportunistic fungal pathogen isolated from the lungs of cystic fibrosis patients.

    PubMed

    Kaur, Jashanpreet; Pethani, Bhavin P; Kumar, Sheemal; Kim, Minkyoung; Sunna, Anwar; Kautto, Liisa; Penesyan, Anahit; Paulsen, Ian T; Nevalainen, Helena

    2015-01-01

    The filamentous fungus Scedosporium aurantiacum and the bacterium Pseudomonas aeruginosa are opportunistic pathogens isolated from lungs of the cystic fibrosis (CF) patients. P. aeruginosa has been known to suppress the growth of a number of CF related fungi such as Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans. However, the interactions between P. aeruginosa and S. aurantiacum have not been investigated in depth. Hence we assessed the effect of P. aeruginosa reference strain PAO1 and two clinical isolates PASS1 and PASS2 on the growth of two clinical S. aurantiacum isolates WM 06.482 and WM 08.202 using solid plate assays and liquid cultures, in a synthetic medium mimicking the nutrient condition in the CF sputum. Solid plate assays showed a clear inhibition of growth of both S. aurantiacum strains when cultured with P. aeruginosa strains PASS1 and PAO1. The inhibitory effect was confirmed by confocal microscopy. In addition to using chemical fluorescent stains, strains tagged with yfp (P. aeruginosa PASS1) and mCherry (S. aurantiacum WM 06.482) were created to facilitate detailed microscopic observations on strain interaction. To our knowledge, this is the first study describing successful genetic transformation of S. aurantiacum. Inhibition of growth was observed only in co-cultures of P. aeruginosa and S. aurantiacum; the cell fractions obtained from independent bacterial monocultures failed to initiate a response against the fungus. In the liquid co-cultures, biofilm forming P. aeruginosa strains PASS1 and PAO1 displayed higher inhibition of fungal growth when compared to PASS2. No change was observed in the inhibition pattern when direct cell contact between the bacterial and fungal strains was prevented using a separation membrane suggesting the involvement of extracellular metabolites in the fungal inhibition. However, one of the most commonly described bacterial virulence factors, pyocyanin, had no effect against either of the S

  1. [Antibacterial activities of combination uses of cefpirome with various antibiotics in vitro against clinically isolated glucose non-fermentative gram-negative rods: part 1. the results against Pseudomonas aeruginosa].

    PubMed

    Suzuki, Y; Koguchi, M; Fukayama, S; Ishihara, R; Oda, S; Deguchi, K

    1996-01-01

    In order to evaluate antibacterial activities of combination uses of cefpirome (CPR) and various antibiotics in vitro, minimum inhibitory concentrations (MICs) of CPR alone and combinations of CPR+other drugs against freshly isolated clinical strains of Pseudomonas aeruginosa. The results are summarized as follows; 1. Combined effects of CPR+beta-lactams, piperacillin (PIPC), aztreonam (AZT), imipenem (IPM) showed wider antibacterial spectra and stronger antibacterial activities than CPR alone with drugs concentrations of CPR and other drugs at sub-MIC levels. At concentrations of sub-MIC levels, antibacterial effects of CPR+PIPC and CPR+AZT combination were strong but CPR+IPM was weaker than those of the former two combinations. It appeared that stronger effects were demonstrated by some combinations against strains that were susceptible to both drugs of combination, but little additive effects were shown against strains that were resistant to both drugs. Antibacterial effect of CPR+fosfomycin combination was the same as those of CPR+PIPC and CPR+AZT combinations. 2. Combined effects of CPR+aminoglycosides (AGs), gentamicin, tobramycin, amikacin showed wider antibacterial spectra and stronger antibacterial activities at sub-MIC levels of CPR or ATs. The effect against CPR-resistant strains was same. But the combined effect was weak against AGs-resistant strains. 3. Effectiveness of combinations of CPR+beta-lactams and CPR+AGs depended on drug susceptibilities of strains tested. We cannot estimate effects of those combinations without investigating drug susceptibility of bacteria being tested. 4. In none of the combinations tested, antagonism was observed.

  2. A major Pseudomonas aeruginosa clone common to patients and aquatic habitats.

    PubMed Central

    Römling, U; Wingender, J; Müller, H; Tümmler, B

    1994-01-01

    The genomic relatedness of 573 Pseudomonas aeruginosa strains from environmental and clinical habitats was examined by digesting the genome with the rare-cutting enzyme SpeI. Thirty-nine strains were collected from environmental habitats mainly of aquatic origin, like rivers, lakes, or sanitary facilities. Four hundred fifty strains were collected from 76 patients with cystic fibrosis (CF) treated at four different centers, and 25 additional clinical isolates were collected from patients suffering from other diseases. Twenty-nine P. aeruginosa isolates were collected from the environment of one CF clinic. Thirty strains from culture collections were of environmental and clinic origin. A common macrorestriction fingerprint pattern was found in 13 of 46 CF patients, 5 of 29 environmental isolates from the same hospital, in a single ear infection isolate from another hospital, and 8 of 38 isolates from aquatic habitats about 300 km away from the CF clinic. The data indicate that closely related variants of one major clone (called clone C) persisted in various spatially and temporally separated habitats. Southern analysis of the clonal variants with six gene probes and two probes for genes coding for rRNA revealed almost the same hybridization patterns. With the exception of the phenotypically rapidly evolving CF isolates, the close relatedness of the strains of the clone was also shown by their identical responses in pyocin typing, phage typing, and serotyping. Besides clone C, three other P. aeruginosa clones were isolated from more than one clinical or environmental source. Images PMID:8031075

  3. Different tolerances to chemical contaminants between unicellular and colonial morph of Microcystis aeruginosa: excluding the differences among different strains.

    PubMed

    Li, Ming; Nkrumah, Philip Nti; Peng, Qiang

    2015-03-21

    In order to ascertain the different tolerances to chemical contaminants in one strain of Microcystis with different morphology, unicellular and colonial Microcystis in one strain was obtained from different conditions of light intensity and temperature. The samples were divided into 8 groups including control (no chemical addition), CuSO4, chloromycetin, and linear alkylbenzene sulfonatelas (LAS) treatments. The cell density, cell viability, superoxide dismutase (SOD), and malonaldehyde of Microcystis were analyzed. It was observed that cell density of both unicellular and colonial Microcystis increased from the beginning to day-5 in the control and the CuSO4 treatments. However, the growth of Microcystis was significantly inhibited in the culture with chloromycetin and LAS treatments. Notably, the inhibition rate was significantly high in unicellular Microcystis relative to the colonial Microcystis. The esterase activity in all the treatments decreased dramatically relating to the control. In addition, the esterase activity in colonial Microcystis was significantly higher than that of the unicellular Microcystis in all the treatments. Although there were no significant differences in activities of SOD between the two morphologies in the control treatments, in all the other treatments, significant differences were observed. The results proved that colony formation of Microcystis could be considered as a strategy in response to chemical stress.

  4. Characterization of two unusual clinically significant Francisella strains.

    PubMed Central

    Clarridge, J E; Raich, T J; Sjösted, A; Sandström, G; Darouiche, R O; Shawar, R M; Georghiou, P R; Osting, C; Vo, L

    1996-01-01

    We have isolated two phenotypically distinct nonfastidious Francisella strains (Fx1 and Fx2) from the blood of compromised patients with pneumonia and compared them with eight other Francisella strains, including Francisella tularensis biovar tularensis, F. tularensis biovar novicida, and F. philomiragia. Our isolates grew well on sheep blood agar, chocolate agar, modified Thayer-Martin agar, and Trypticase soy agar. Fx1 and Fx2 were determined to be within the Francisella genus by cellular fatty acid analysis and by the utilization of glucose, production of H2S and catalase, and lack of motility, oxidase, nitrate reductase, and gelatinase. They were additionally shown to belong to the species F. tularensis by sequencing of two variable regions comprising approximately 500 nucleotides of the 16S rRNA gene. Also, RNA probe hybridization confirmed their belonging to the species F. tularensis. However, the new strains, which are not identical, are distinguished from other F. tularensis strains by growth characteristics, repetitive extragenic palindromic PCR fragment pattern, and some biochemical tests. Key biochemical differences included the findings that Fx1 was positive for beta-galactosidase and arabinose hydrolysis and that both strains were citrulline ureidase positive and glycerol negative. Commercial F. tularensis antiserum agglutinated stock F. tularensis strains but not Fx1, Fx2, F. tularensis biovar novicida, or F. philomiragia; serum from either patient failed to agglutinate or only weakly agglutinated commercial antigen but showed agglutination when tested against each patient's respective isolate. Fx1 and Fx2 produced beta-lactamase. Because of their good growth, negative serology, and biochemical profile, the organisms could be misidentified in the clinical laboratory if standard strategies or commercial identification systems are used. PMID:8818897

  5. Establishment and multi drug resistance evolution of ST235 Pseudomonas aeruginosa strains in the intensive care unit of a Colombian hospital.

    PubMed

    Martinez, Elena; Pérez, Javier Escobar; Buelvas, Francisco; Tovar, Catalina; Vanegas, Natasha; Stokes, H W

    2014-12-01

    Drug resistant Pseudomonas aeruginosa represents a therapeutic challenge. To assess the diversity of P. aeruginosa antibiotic resistant variants, isolates were recovered from hospital patients in Colombia. Thirty of 60 isolates contained class 1 integrons and five were of Sequence Type ST235 having appeared in a single intensive care unit. All five possessed an unusual integron but showed differences in gene cassette content and the presence/absence of insertion sequence IS26. This showed that differences can arise rapidly, even within a single ICU. Also, the emergence of IS26 in P. aeruginosa is contributing to the evolution of resistance in this bacterium.

  6. 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

  7. 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.

  8. Blood pressure and hepatocellular effects of the cyclic heptapeptide toxin produced by the freshwater cyanobacterium (blue-green alga) Microcystis aeruginosa strain PCC-7820.

    PubMed

    Theiss, W C; Carmichael, W W; Wyman, J; Bruner, R

    1988-01-01

    Laboratory rats and mice were used to investigate the hepatotoxicity caused by the cyclic heptapeptide (mol. wt 994) termed microcystin-LR. Microcystin-LR (also known as cyanoginosin-LR) is produced by the freshwater cyanobacterium (blue-green alga) M. aeruginosa strain PCC-7820. In time course histopathology studies with mice significant liver damage, with an absence of pulmonary emboli, were observed after 15 min. Pulmonary emboli did not appear until 1 hr. In rats, significant liver damage and the presence of occasional emboli were observed at 20 min. Pulmonary emboli did not contain fibrin nor appear life-threatening in any case and resembled the globular eosinophilic debris found in the liver sinusoids and central veins. Measurements of rat femoral arterial, jugular venous and hepatic portal venous blood pressures during the course of toxicity revealed a slowly declining arterial pressure and stable, normal venous pressures. Blood lactic acid levels rose in parallel with the fall in arterial pressure, a pattern typical of hemorrhagic shock. There was no indication of venous congestion that would accompany right heart failure. Isolated, perfused rat livers dosed with toxin showed rapid changes in the liver, including cessation of bile flow within 10 min and complete obliteration of normal lobular architecture within 60 min. No effect of the toxin was observed in isolated perfused rat heart. We conclude that in the mouse and rat, microcystin-LR is a potent, rapid-acting, direct hepatotoxin, with the immediate cause of death in acute toxicities being hemorrhagic shock secondary to massive hepatocellular necrosis and collapse of hepatic parenchyma.

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

    PubMed Central

    Hijazi, Sarah; Visca, Paolo; Frangipani, Emanuela

    2017-01-01

    Pseudomonas aeruginosa is a challenging pathogen due to both innate and acquired resistance to antibiotics. It is capable of causing a variety of infections, including chronic lung infection in cystic fibrosis (CF) patients. Given the importance of iron in bacterial physiology and pathogenicity, iron-uptake and metabolism have become attractive targets for the development of new antibacterial compounds. P. aeruginosa can acquire iron from a variety of sources to fulfill its nutritional requirements both in the environment and in the infected host. The adaptation of P. aeruginosa to heme iron acquisition in the CF lung makes heme utilization pathways a promising target for the development of new anti-Pseudomonas drugs. Gallium [Ga(III)] is an iron mimetic metal which inhibits P. aeruginosa growth by interfering with iron-dependent metabolism. The Ga(III) complex of the heme precursor protoporphyrin IX (GaPPIX) showed enhanced antibacterial activity against several bacterial species, although no inhibitory effect has been reported on P. aeruginosa. Here, we demonstrate that GaPPIX is indeed capable of inhibiting the growth of clinical P. aeruginosa strains under iron-deplete conditions, as those encountered by bacteria during infection, and that GaPPIX inhibition is reversed by iron. Using P. aeruginosa PAO1 as model organism, we show that GaPPIX enters cells through both the heme-uptake systems has and phu, primarily via the PhuR receptor which plays a crucial role in P. aeruginosa adaptation to the CF lung. We also demonstrate that intracellular GaPPIX inhibits the aerobic growth of P. aeruginosa by targeting cytochromes, thus interfering with cellular respiration. PMID:28184354

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

    PubMed

    Hijazi, Sarah; Visca, Paolo; Frangipani, Emanuela

    2017-01-01

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

  11. O serotype-independent susceptibility of Pseudomonas aeruginosa to lectin-like pyocins

    PubMed Central

    Ghequire, Maarten G K; Dingemans, Jozef; Pirnay, Jean-Paul; De Vos, Daniel; Cornelis, Pierre; De Mot, René

    2014-01-01

    Lectin-like bacteriocins of the LlpA family, originally identified in plant-associated bacteria, are narrow-spectrum antibacterial proteins composed of two tandemly organized monocot mannose-binding lectin (MMBL) domains. The LlpA-like bacteriocin of Pseudomonas aeruginosa C1433, pyocin L1, lacks any similarity to known P. aeruginosa bacteriocins. The initial interaction of pyocin L1 with target cells is mediated by binding to d-rhamnose, present in the common polysaccharide antigen of lipopolysaccharides (LPS), but the actual cytotoxic mechanism is unknown. In this study, we characterized the activity range of pyocin L1 and two additional L pyocins revealed by genome mining, representing two highly diverged LlpA groups in P. aeruginosa. The recombinant proteins exhibit species-specific antagonistic activities down to nanomolar concentrations against clinical and environmental P. aeruginosa strains, including several multidrug-resistant isolates. The overlap in target strain spectrum between two close homologues of the pyocin L1 group is only minimal, contrasting with the considerable spectral redundancy of LlpA proteins reported for other Pseudomonas species. No correlation was found between L pyocin susceptibility and phylogenetic relatedness of P. aeruginosa isolates. Sensitive strains were retrieved in 13 out of 15 O serotypes tested, excluding the possibility that the highly variable and immunogenic O serotype antigen of the LPS coating would represent a dominant susceptibility-discriminating factor. PMID:25224846

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

    PubMed Central

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

    2017-01-01

    Prophages are major contributors to horizontal gene transfer and drive the evolution and diversification of bacteria. Here, we describe the characterization of a prophage element designated pp3 in the clinical Pseudomonas aeruginosa isolate PA1. pp3 spontaneously excises from the PA1 genome and circularizes at a very high frequency of 25%. pp3 is likely to be a defective prophage due to its inability to form plaques on P. aeruginosa indicator strains, and no phage particles could be detected in PA1 supernatants. The pp3-encoded integrase is essential for excision by mediating site-specific recombination at the 26-bp attachment sequence. Using a filter mating experiment, we demonstrated that pp3 can transfer into P. aeruginosa recipient strains that do not possess this element naturally. Upon transfer, pp3 integrates into the same attachment site as in PA1 and maintains the ability to excise and circularize. Furthermore, pp3 significantly promotes biofilm formation in the recipient. Sequence alignment reveals that the 26-bp attachment site recognized by pp3 is conserved in all P. aeruginosa strains sequenced to date, making it possible that pp3 could be extensively disseminated in P. aeruginosa. This work improves our understanding of the ways in which prophages influence bacterial behavior and evolution. PMID:28346467

  13. 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

  14. Chemical analysis, inhibition of biofilm formation and biofilm eradication potential of Euphorbia hirta L. against clinical isolates and standard strains

    PubMed Central

    2013-01-01

    Background The frequent occurrences of antibiotic-resistant biofilm forming pathogens have become global issue since various measures that had been taken to curb the situation led to failure. Euphorbia hirta, is a well-known ethnomedicinal plant of Malaysia with diverse biological activities. This plant has been used widely in traditional medicine for the treatment of gastrointestinal, bronchial and respiratory ailments caused by infectious agents. Methods In the present study, chemical compositions of methanol extract of E. hirta L. aerial part was analyzed by gas chromatography and gas chromatography coupled to mass spectrometry. A relevant in vitro model was developed to assess the potency of the E. hirta extract to inhibit the bacterial biofilm formation as well as to eradicate the established biofilms. Besides biofilm, E. hirta extract was also evaluated for the inhibition efficacy on planktonic cells using tetrazolium microplate assay. For these purposes, a panel of clinically resistant pathogens and American type culture collection (ATCC) strains were used. Results The methanolic extract of aerial part of E. hirta was predominantly composed of terpenoid (60.5%) which is often regarded as an active entity accountable for the membrane destruction and biofilm cell detachment. The highest antibacterial effect of crude E. hirta extract was observed in the clinical isolates of Pseudomonas aeruginosa with minimum inhibitory concentration (MIC) value of 0.062 mg/ml. The extract also displayed potent biofilm inhibition and eradication activity against P. aeruginosa with minimum biofilm inhibition concentration (MBIC) and minimum biofilm eradication concentration (MBEC) values of 0.25 mg/ml and 0.5 mg/ml, respectively. Conclusions The crude methanol extract of E. hirta has proven to have interesting and potential anti-biofilm properties. The findings from this study will also help to establish a very promising anti-infective phytotherapeutical to be exploited in

  15. Pyoverdine and proteases affect the response of Pseudomonas aeruginosa to gallium in human serum.

    PubMed

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

    2015-09-01

    Gallium is an iron mimetic which has recently been repurposed as an antibacterial agent due to its capability to disrupt bacterial iron metabolism. In this study, the antibacterial activity of gallium nitrate [Ga(NO3)3] was investigated in complement-free human serum (HS) on 55 Pseudomonas aeruginosa clinical isolates from cystic fibrosis and non-cystic fibrosis patients. The susceptibility of P. aeruginosa to Ga(NO3)3 in HS was dependent on the bacterial ability to acquire iron from serum binding proteins (i.e., transferrin). The extent of serum protein degradation correlated well with P. aeruginosa growth in HS, while pyoverdine production did not. However, pyoverdine-deficient P. aeruginosa strains were unable to grow in HS and overcome iron restriction, albeit capable of releasing proteases. Predigestion of HS with proteinase K promoted the growth of all strains, irrespective of their ability to produce proteases and/or pyoverdine. The MICs of Ga(NO3)3 were higher in HS than in an iron-poor Casamino Acids medium, where proteolysis does not affect iron availability. Coherently, strains displaying high proteolytic activity were less susceptible to Ga(NO3)3 in HS. Our data support a model in which both pyoverdine and proteases affect the response of P. aeruginosa to Ga(NO3)3 in HS. The relatively high Ga(NO3)3 concentration required to inhibit the growth of highly proteolytic P. aeruginosa isolates in HS poses a limitation to the potential of Ga(NO3)3 in the treatment of P. aeruginosa bloodstream infections.

  16. In vitro potentiation of carbapenems with ME1071, a novel metallo-beta-lactamase inhibitor, against metallo-beta-lactamase- producing Pseudomonas aeruginosa clinical isolates.

    PubMed

    Ishii, Yoshikazu; Eto, Maki; Mano, Yoko; Tateda, Kazuhiro; Yamaguchi, Keizo

    2010-09-01

    ME1071, a maleic acid derivative, is a novel specific inhibitor for metallo-beta-lactamases (MBL). In this study, the potentiation of ME1071 in combination with several beta-lactams was evaluated using MBL-producing Pseudomonas aeruginosa isolates. The rates of susceptibility of MBL producers to carbapenems (imipenem, biapenem, and doripenem) and ceftazidime were increased by 8 to 27% in the presence of 32 microg/ml of ME1071. The corresponding resistance rates were decreased by 13 to 46%, respectively. On the other hand, ME1071 showed weaker or no potentiation with non-MBL producers. The K(i) value of ME1071 for IMP-1 was 0.4 microM, significantly lower than the K(m) values of carbapenems for the IMP-1 enzyme. On the other hand, the K(i) value of ME1071 for VIM-2 was 120 microM, higher than the K(m) values of carbapenems for the VIM-2 enzyme. Results of this study indicate that ME1071 can potentiate the activity of ceftazidime and carbapenems against MBL-producing strains of P. aeruginosa.

  17. Social cheating in Pseudomonas aeruginosa quorum sensing.

    PubMed

    Sandoz, Kelsi M; Mitzimberg, Shelby M; Schuster, Martin

    2007-10-02

    In a process termed quorum sensing, bacteria use diffusible chemical signals to coordinate cell density-dependent gene expression. In the human pathogen Pseudomonas aeruginosa, quorum sensing controls hundreds of genes, many of which encode extracellular virulence factors. Quorum sensing is required for P. aeruginosa virulence in animal models. Curiously, quorum sensing-deficient variants, most of which carry a mutation in the gene encoding the central quorum sensing regulator lasR, are frequently isolated from acute and chronic infections. The mechanism for their emergence is not known. Here we provide experimental evidence suggesting that these lasR mutants are social cheaters that cease production of quorum-controlled factors and take advantage of their production by the group. We detected an emerging subpopulation of lasR mutants after approximately 100 generations of in vitro evolution of the P. aeruginosa wild-type strain under culture conditions that require quorum sensing for growth. Under such conditions, quorum sensing appears to impose a metabolic burden on the proliferating bacterial cell, because quorum-controlled genes not normally induced until cessation of growth were highly expressed early in growth, and a defined lasR mutant showed a growth advantage when cocultured with the parent strain. The emergence of quorum-sensing-deficient variants in certain environments is therefore an indicator of high quorum sensing activity of the bacterial population as a whole. It does not necessarily indicate that quorum sensing is insignificant, as has previously been suggested. Thus, novel antivirulence strategies aimed at disrupting bacterial communication may be particularly effective in such clinical settings.

  18. Genotypic diversity and virulence markers of Yersinia enterocolitica biotype 1A strains isolated from clinical and non-clinical origins.

    PubMed

    Campioni, Fábio; Falcão, Juliana P

    2014-03-01

    Yersinia enterocolitica biotype 1A (B1A) strains are considered as non-pathogenic; however, some reports have identified some strains as the causal agents of infection. In South America, few studies molecularly characterized the strains of this biotype. This work typed 51 B1A strains isolated from clinical and non-clinical sources from Brazil and Chile by Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR) to elucidate their genotypic diversity, and verify the distribution of 11 virulence markers by PCR. The strains were divided into two groups, ERIC-A and ERIC-B, clustered independently of their clinical or non-clinical origin. No differences were observed in the frequencies of the virulence markers between clinical and non-clinical strains. However, the genes ystB, hreP and myfA occurred exclusively in the strains of the group ERIC-A. Some clinical and non-clinical strains were clustered in the same genetic group and presented the same number of virulence markers, which might suggest the role of the environment and food as a potential source of infection for humans and animals. The results corroborate with the hypothesis that B1A strains are divided into two main clusters that differ in the frequency of some virulence markers, a fact observed for the first time in South American strains.

  19. Efflux-mediated fluoroquinolone resistance in the multidrug-resistant Pseudomonas aeruginosa clinical isolate PA7: identification of a novel MexS variant involved in upregulation of the mexEF-oprN multidrug efflux operon

    PubMed Central

    Morita, Yuji; Tomida, Junko; Kawamura, Yoshiaki

    2014-01-01

    The emergence of multidrug-resistant Pseudomonas aeruginosa has become a serious problem in medical settings. P. aeruginosa clinical isolate PA7 is resistant to fluoroquinolones, aminoglycosides, and most β-lactams but not imipenem. In this study, enhanced efflux-mediated fluoroquinolone resistance of PA7 was shown to reflect increased expression of two resistance nodulation cell division (RND) -type multidrug efflux operons, mexEF-oprN and mexXY-oprA. Such a clinical isolate has rarely been reported because MexEF-OprN-overproducing mutants often increase susceptibility to aminoglycosides apparently owing to impairment of the MexXY system. A mutant of PA7 lacking three RND-type multidrug efflux operons (mexAB-oprM, mexEF-oprN, and mexXY-oprA) was susceptible to all anti-pseudomonas agents we tested, supporting an idea that these RND-type multidrug efflux transporters are molecular targets to overcome multidrug resistance in P. aeruginosa. mexEF-oprN-upregulation in P. aeruginosa PA7 was shown due to a MexS variant harboring the Valine-155 amino acid residue. This is the first genetic evidence shown that a MexS variant causes mexEF-oprN-upregulation in P. aeruginosa clinical isolates. PMID:25653649

  20. Automated ribotyping provides rapid phylogenetic subgroup affiliation of clinical extraintestinal pathogenic Escherichia coli strains.

    PubMed

    Clermont, O; Cordevant, C; Bonacorsi, S; Marecat, A; Lange, M; Bingen, E

    2001-12-01

    Using the automated Riboprinter system, we have initiated the construction of an electronic Riboprint database composed of 72 ECOR reference strains and 15 archetypal virulent strains in order to provide a new simple molecular characterization method. More than 90% of the ECOR strains clustered in their original phylogenetic group. All but one of the archetypal virulent strains had a profile identical to that of one of the ECOR strains and could be easily affiliated with a phylogenetic group. This method appears to be an accurate and practical tool especially for investigating the genetic relationship between clinical extraintestinal pathogenic strains and B2 subgroup ECOR strains or archetypal pathotype strains.

  1. A Novel Insight into Dehydroleucodine Mediated Attenuation of Pseudomonas aeruginosa Virulence Mechanism

    PubMed Central

    Mustafi, S.; Veisaga, M. L.; López, L. A.; Barbieri, M. A.

    2015-01-01

    Increasing resistance of Pseudomonas aeruginosa (P. aeruginosa) to conventional treatments demands the search for novel therapeutic strategies. In this study, the antimicrobial activity of dehydroleucodine (DhL), a sesquiterpene lactone obtained from Artemisia (A.) douglasiana, was screened against several pathogenic virulence effectors of P. aeruginosa. In vitro, minimum inhibitory concentration of DhL was determined against P. aeruginosa strains PAO1, PA103, PA14, and multidrug resistant clinical strain, CDN118. Results showed that DhL was active against each strain where PAO1 and PA103 showed higher susceptibility (MIC 0.48 mg/mL) as compared to PA14 (MIC 0.96 mg/mL) and CDN118 (MIC 0.98 mg/mL). Also, when PAO1 strain was grown in the presence of DhL (MIC50, 0.12 mg/mL), a delay in the generation time was noticed along with significant inhibition of secretory protease and elastase activities, interruption in biofilm attachment phase in a stationary culture, and a significant decline in Type III effector ExoS. At MIC50, DhL treatment increased the sensitivity of P. aeruginosa towards potent antibiotics. Furthermore, treatment of P. aeruginosa with DhL prevented toxin-induced apoptosis in macrophages. These observations suggest that DhL activity was at the bacterial transcriptional level. Hence, antimicrobial activity of DhL may serve as leads in the development of new anti-Pseudomonas pharmaceuticals. PMID:26640783

  2. 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

  3. In vitro sensitivity of Acinetobacter baumannii and Pseudomonas aeruginosa to carbapenems among intensive care unit patients.

    PubMed

    Guzek, A; Korzeniewski, K; Nitsch-Osuch, Aneta; Rybicki, Z; Prokop, E

    2013-01-01

    Acinetobacter baumannii and Pseudomonas aeruginosa pathogens are the most common causes of fatal pneumonia among patients treated in Intensive Care Units (ICU). Carbapenems remain a group of antibiotics characterized by the highest effectiveness in treatment of heavy infections of the lower respiratory tract. This study compared in vitro sensitivity of A. baumannii and P. aeruginosa to three carbapenems: imipenem, meropenem and doripenem. The material was collected from 71 patients treated in the ICU from April 2009 to January 2010. Bronchial tree was the predominant source of samples. Fifty-four strains of A. baumannii and 17 strains of P. aeruginosa were analyzed. Sensitivity to carbapenems was interpreted in line with Clinical and Laboratory Standard Institute (CLSI) and European Committee for Antimicrobial Susceptibility Testing (EUCAST) criteria (imipenem and meropenem) or in compliance with the Food and Drug Administration (FDA) and CLSI guidelines (doripenem). We found that A. baumannii was significantly more often sensitive to imipenem than to doripenem and meropenem, but only according to the CLSI and FDA and not EUCAST criteria. The sensitivity of P. aeruginosa was higher to imipenem than to doripenem and meropenem, according to both CLSI and EUCAST criteria (64.7 %). We conclude that the EUCAST criteria demonstrate a higher rigor than those of CLSI and FDA in the determination of carbapenems sensitivity. Imipenem appears more effective than doripenem and meropenem in treatment of A. baumannii and P. aeruginosa infections.

  4. Pseudomonas aeruginosa in a neonatal intensive care unit: molecular epidemiology and infection control measures

    PubMed Central

    2009-01-01

    Background Pseudomonas aeruginosa, a non-fermentative, gram-negative rod, is responsible for a wide variety of clinical syndromes in NICU patients, including sepsis, pneumonia, meningitis, diarrhea, conjunctivitis and skin infections. An increased number of infections and colonisations by P. aeruginosa has been observed in the neonatal intensive care unit (NICU) of our university hospital between 2005 and 2007. Methods Hand disinfection compliance before and after an educational programme on hand hygiene was evaluated. Identification of microrganisms was performed using conventional methods. Antibiotic susceptibility was evaluated by MIC microdilution. Genotyping was performed by PFGE analysis. Results The molecular epidemiology of Pseudomonas aeruginosa in the NICU of the Federico II University hospital (Naples, Italy) and the infection control measures adopted to stop the spreading of P. aeruginosa in the ward were described. From July 2005 to June 2007, P. aeruginosa was isolated from 135 neonates and caused severe infections in 11 of them. Macrorestriction analysis of clinical isolates from 90 neonates identified 20 distinct genotypes, one major PFGE type (A) being isolated from 48 patients and responsible for 4 infections in 4 of them, four other distinct recurrent genotypes being isolated in 6 to 4 patients. Seven environmental strains were isolated from the hand of a nurse and from three sinks on two occasions, two of these showing PFGE profiles A and G identical to two clinical isolates responsible for infection. The successful control of the outbreak was achieved through implementation of active surveillance of healthcare-associated infections in the ward together with environmental microbiological sampling and an intense educational programme on hand disinfection among the staff members. Conclusion P. aeruginosa infections in the NICU were caused by the cross-transmission of an epidemic clone in 4 neonates, and by the selection of sporadic clones in 7

  5. Correlation Between Virulence Genotype and Fluoroquinolone Resistance in Carbapenem-Resistant Pseudomonas aeruginosa

    PubMed Central

    Cho, Hye Hyun; Kwon, Kye Chul; Kim, Semi

    2014-01-01

    Background Pseudomonas aeruginosa is a clinically important pathogen that causes opportunistic infections and nosocomial outbreaks. Recently, the type III secretion system (TTSS) has been shown to play an important role in the virulence of P. aeruginosa. ExoU, in particular, has the greatest impact on disease severity. We examined the relationship among the TTSS effector genotype (exoS and exoU), fluoroquinolone resistance, and target site mutations in 66 carbapenem-resistant P. aeruginosa strains. Methods Sixty-six carbapenem-resistant P. aeruginosa strains were collected from patients in a university hospital in Daejeon, Korea, from January 2008 to May 2012. Minimum inhibitory concentrations (MICs) of fluoroquinolones (ciprofloxacin and levofloxacin) were determined by using the agar dilution method. We used PCR and sequencing to determine the TTSS effector genotype and quinolone resistance-determining regions (QRDRs) of the respective target genes gyrA, gyrB, parC, and parE. Results A higher proportion of exoU+ strains were fluoroquinolone-resistant than exoS+ strains (93.2%, 41/44 vs. 45.0%, 9/20; P≤0.0001). Additionally, exoU+ strains were more likely to carry combined mutations than exoS+ strains (97.6%, 40/41 vs. 70%, 7/10; P=0.021), and MIC increased as the number of active mutations increased. Conclusions The recent overuse of fluoroquinolone has led to both increased resistance and enhanced virulence of carbapenem-resistant P. aeruginosa. These data indicate a specific relationship among exoU genotype, fluoroquinolone resistance, and resistance-conferring mutations. PMID:24982833

  6. Sequence Types 235, 111, and 132 Predominate among Multidrug-Resistant Pseudomonas aeruginosa Clinical Isolates in Croatia

    PubMed Central

    Izdebski, Radosław; Butic, Iva; Jelic, Marko; Abram, Maja; Koscak, Iva; Baraniak, Anna; Hryniewicz, Waleria; Gniadkowski, Marek; Tambic Andrasevic, Arjana

    2014-01-01

    A population analysis of 103 multidrug-resistant Pseudomonas aeruginosa isolates from Croatian hospitals was performed. Twelve sequence types (STs) were identified, with a predominance of international clones ST235 (serotype O11 [41%]), ST111 (serotype O12 [15%]), and ST132 (serotype O6 [11%]). Overexpression of the natural AmpC cephalosporinase was common (42%), but only a few ST235 or ST111 isolates produced VIM-1 or VIM-2 metallo-β-lactamases or PER-1 or GES-7 extended-spectrum β-lactamases. PMID:25070098

  7. Nutritional requirement among Pseudomonas aeruginosa isolates recovered from respiratory clinical specimens at a tertiary hospital from South of Brazil

    PubMed Central

    Perez, Leandro Reus Rodrigues; de Freitas, Ana Lúcia Peixoto; Barth, Afonso Luís

    2011-01-01

    We screened 349 isolates of P. aeruginosa from cystic fibrosis (CF+) and non-cystic fibrosis (CF-) patients for the auxotrophy. Fourteen (4.0%) were auxotrophic and among them only one was recovered from CF-patient showing that this characteristic is strongly associated with cystic fibrosis. In total, a requirement for 5 different compounds (or combination) was verified and, of these, methionine was the most common single amino acid required. Only one auxotrophic isolate was no able to produce biofilm in vitro. PMID:24031723

  8. Osmoregulation in Pseudomonas aeruginosa under hyperosmotic shock.

    PubMed

    Velasco, R; Burgoa, R; Flores, E; Hernández, E; Villa, A; Vaca, S

    1995-01-01

    Pseudomonas aeruginosa PAO1 strain was found to be able to tolerate 700 mM NaCl. 0.5 mM of the osmoprotectant betaine restablished the growth of this strain in 1200 mM NaCl. Intracellular K+ and glutamate concentrations of P. aeruginosa PAO1 after an hyperosmotic shock (400 mM NaCl) showed a permanent increase. Adition of betaine (0.5 mM) to the medium with NaCl had an inhibitory effect on the intracellular accumulation of glutamate. The results indicate that P. aeruginosa PAO1 resists high NaCl concentrations, K+ accumulation and glutamate synthesis probably being the first mechanisms involved in adaptation to osmotic stress. Also is is demonstrated that betaine modulates intracellular glutamate levels in osmotically stressed P. aeruginosa PAO1.

  9. Efficacy of 1% acetic acid in the treatment of chronic wounds infected with Pseudomonas aeruginosa: prospective randomised controlled clinical trial.

    PubMed

    Madhusudhan, V L

    2016-12-01

    Chronic wounds are those wounds that are persistent and do not respond to any sort of treatment. The concept of using topical antiseptics on open wounds is to prevent and treat infections. They also help to shorten the time taken to heal the wounds. The use of topical agents on wounds to prevent infection is a minimal ability to develop resistance to the microorganisms. Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen with innate resistance to many antibiotics. In places that are economically backward, these problems get compounded by the inability of patients to afford newer expensive drugs. Topically applied dilute acetic acid, which is cheap and easily available, has been found to be effective in such chronic wounds. In the present study, an attempt has been made to use 1% acetic acid as the sole antimicrobial agent for the treatment of pseudomonal wound infections. A control limb was used in which the wounds were treated with normal saline. Our objective was to evaluate the efficacy of acetic acid in low concentration of 1% in chronic wounds infected with P. aeruginosa. This was a prospective study conducted over a period of 6 months.

  10. 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.

  11. Evaluating the influence of light intensity in mcyA gene expression and microcystin production in toxic strains of Planktothrix agardhii and Microcystis aeruginosa.

    PubMed

    Salvador, Daniel; Churro, Catarina; Valério, Elisabete

    2016-04-01

    Cyanobacteria are phytoplanktonic organisms widely occurring in freshwaters, being frequently associated with the production of toxins, namely microcystins (MCs). MCs are produced non-ribosomally by a multienzyme complex (mcy genes). It has been reported that environmental factors, such as light intensity, can influence toxin production. The aim of this study was to assess the influence of light intensity in the transcription of the mcyA gene and corresponding production of microcystins in toxic isolates of Planktothrix agardhii, where little is known, and compare them to Microcystis aeruginosa. For that purpose, cultures were exposed to three different light intensities (4, 20 and 30 μmol photons m(-2) s(-1)) for 18 days at 20 ± 1 °C. The growth was followed daily using absorbance readings. Samples were collected at each growth stage for cell counting, microcystins quantification and RNA extraction. The level of transcripts was quantified by RT-qPCR and the relative expression determined using 16S rDNA, gltA and rpoC1 as reference genes. The most stable reference genes in M. aeruginosa were rpoC1 and gltA, whereas in P. agardhii were 16S rDNA and gltA. There was a correspondence between the growth rate and light intensity in M. aeruginosa and P. agardhii. The growth rates for both species were lower at 4 and higher at 30 μmol photons m(-2) s(-1). Microcystin concentration per cell was similar between light intensities in M. aeruginosa and over time, while in P. agardhii it was higher in the stationary phase at 4 μmol photons m(-2) s(-1). There were differences in the expression of mcyA between the two species. In M. aeruginosa, the highest levels of expression occurred at 4 μmol photons m(-2) s(-1) in the adaptation phase, whereas for P. agardhii it was at 4μmol photons m(-2) s(-1) in the exponential growth phase. Our results indicate that the light intensities tested had distinct influences on the growth, microcystin production and mcyA expression levels

  12. In vitro comparison of Pseudomonas aeruginosa isolates with various susceptibilities to aminoglycosides and ten beta-lactam antibiotics.

    PubMed Central

    Wu, D H; Baltch, A L; Smith, R P

    1984-01-01

    Susceptibilities of 98 clinical isolates of Pseudomonas aeruginosa, including 33 strains with known mechanisms of amikacin resistance, were tested by the agar dilution method against 10 beta-lactam drugs. Ceftazidime, imipenem, and cefsulodin had the greatest activity, regardless of the aminoglycoside susceptibilities. The strains which were highly resistant to amikacin appeared to be less susceptible to some beta-lactam drugs, especially if their resistance was related to amikacin-inactivating enzymes; statistical significance, however, was observed for aztreonam only. PMID:6428308

  13. Inhibition by EGTA of the formation of a biofilm by clinical strains of Staphylococcus aureus.

    PubMed

    Liesse Iyamba, J M; Seil, M; Nagant, C; Dulanto, S; Deplano, A; El Khattabi, C; Takaisi Kikuni, N B; Dehaye, J P

    2014-07-01

    The effect of EGTA on the adhesion and on the formation of a biofilm by two reference and eight clinical strains of Staphylococcus aureus was studied. All the clinical strains were isolated from patients from Kinshasa. Spa typing confirmed that these clinical strains were distinct. The Biofilm Ring Test (BFRT®) showed that EGTA (100 µM-10 mM) inhibited the adhesion of the four clinical methicillin-resistant (MRSA) strains and the crystal violet staining method that it inhibited the formation of a biofilm by all the strains. Divalent cations abolished the effect of EGTA on the formation of a biofilm, specially in the clinical MRSA strains. EGTA had no effect on established biofilms. Only concentrations of EGTA higher than 10 mM were toxic to eukaryotic cells. Our results establish the effectiveness and the safety of lock solutions with EGTA to prevent the formation in vitro of biofilms by S. aureus.

  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.

  15. Identification of plasmid OXA and other β-lactamase genes among carbapenem-resistant isolates of Pseudomonas aeruginosa from the Clinical University Hospital in northeastern Poland.

    PubMed

    Sacha, Paweł; Michalska, Anna; Ojdana, Dominika; Wieczorek, Piotr; Hauschild, Tomasz; Majewski, Piotr; Tryniszewska, Elżbieta

    2015-04-01

    The aim of the study was to evaluate the prevalence of OXA and other β-lactamase genes, antibiotic susceptibility, and the genetic relatedness among clinical isolates of P. aeruginosa resistant to carbapenems. The presence of bla- OXA genes was demonstrated in 48% of isolates belonging to four PFGE profiles. Most of them contained the blaOXA-2 gene (88.3%). Other blaOXA genes (Ps1310 with blaOXA-30 and Ps1309 with blaOXA-10) were found in only two isolates. The tested isolates also contained other β-lactamase genes such as blaVIM-2, blaVIM-4, blaSHV-5, and blaTEM-1. All isolates were susceptible only to colistin (100%).

  16. Developing an international Pseudomonas aeruginosa reference panel.

    PubMed

    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

    2013-12-01

    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.

  17. Loss of Social Behaviours in Populations of Pseudomonas aeruginosa Infecting Lungs of Patients with Cystic Fibrosis

    PubMed Central

    Jiricny, Natalie; Molin, Søren; Foster, Kevin; Diggle, Stephen P.; Scanlan, Pauline D.; Ghoul, Melanie; Johansen, Helle Krogh; Santorelli, Lorenzo A.; Popat, Roman; West, Stuart A.; Griffin, Ashleigh S.

    2014-01-01

    Pseudomonas aeruginosa, is an opportunistic, bacterial pathogen causing persistent and frequently fatal infections of the lung in patients with cystic fibrosis. Isolates from chronic infections differ from laboratory and environmental strains in a range of traits and this is widely interpreted as the result of adaptation to the lung environment. Typically, chronic strains carry mutations in global regulation factors that could effect reduced expression of social traits, raising the possibility that competitive dynamics between cooperative and selfish, cheating strains could also drive changes in P. aeruginosa infections. We compared the expression of cooperative traits - biofilm formation, secretion of exo-products and quorum sensing (QS) - in P. aeruginosa isolates that were estimated to have spent different lengths of time in the lung based on clinical information. All three exo-products involved in nutrient acquisition were produced in significantly smaller quantities with increased duration of infection, and patterns across four QS signal molecules were consistent with accumulation over time of mutations in lasR, which are known to disrupt the ability of cells to respond to QS signal. Pyocyanin production, and the proportion of cells in biofilm relative to motile, free-living cells in liquid culture, did not change. Overall, our results confirm that the loss of social behaviour is a consistent trend with time spent in the lung and suggest that social dynamics are potentially relevant to understanding the behaviour of P. aeruginosa in lung infections. PMID:24454693

  18. Loss of social behaviours in populations of Pseudomonas aeruginosa infecting lungs of patients with cystic fibrosis.

    PubMed

    Jiricny, Natalie; Molin, Søren; Foster, Kevin; Diggle, Stephen P; Scanlan, Pauline D; Ghoul, Melanie; Johansen, Helle Krogh; Santorelli, Lorenzo A; Popat, Roman; West, Stuart A; Griffin, Ashleigh S

    2014-01-01

    Pseudomonas aeruginosa, is an opportunistic, bacterial pathogen causing persistent and frequently fatal infections of the lung in patients with cystic fibrosis. Isolates from chronic infections differ from laboratory and environmental strains in a range of traits and this is widely interpreted as the result of adaptation to the lung environment. Typically, chronic strains carry mutations in global regulation factors that could effect reduced expression of social traits, raising the possibility that competitive dynamics between cooperative and selfish, cheating strains could also drive changes in P. aeruginosa infections. We compared the expression of cooperative traits - biofilm formation, secretion of exo-products and quorum sensing (QS) - in P. aeruginosa isolates that were estimated to have spent different lengths of time in the lung based on clinical information. All three exo-products involved in nutrient acquisition were produced in significantly smaller quantities with increased duration of infection, and patterns across four QS signal molecules were consistent with accumulation over time of mutations in lasR, which are known to disrupt the ability of cells to respond to QS signal. Pyocyanin production, and the proportion of cells in biofilm relative to motile, free-living cells in liquid culture, did not change. Overall, our results confirm that the loss of social behaviour is a consistent trend with time spent in the lung and suggest that social dynamics are potentially relevant to understanding the behaviour of P. aeruginosa in lung infections.

  19. Enterotoxin production, phage typing and serotyping of Staphylococcus aureus strains isolated from clinical materials and food.

    PubMed Central

    Melconian, A. K.; Brun, Y.; Fleurette, J.

    1983-01-01

    The production of enterotoxins A, B, C and F by strains of Staphylococcus aureus isolated from various clinical sources and from isolates implicated in food poisoning was investigated. One hundred and ninety one of the 374 clinical strains (51.1%) were found to be enterotoxigenic; of these, 81 (27.7%) strains produced enterotoxin A, 57 (15.3%) strains produced enterotoxin B, 23 (6.2%) strains produced enterotoxin C, and 64 (17.1%) strains produced enterotoxin F. These enterotoxigenic strains were most frequently lysed by phages of group III (21.5%) or were not typable (22%). Eighteen of the 29 strains implicated in food poisoning were enterotoxigenic. The correlation of antigens and bacteriophage patterns with enterotoxigenicity was determined: enterotoxin A being related to a4 antigen, enterotoxin B to phages of 94/96 complex with c1, o antigens, and enterotoxin F to phages of group I with 2632, k1k2, m antigens. PMID:6227656

  20. Characterization of the first double-stranded RNA bacteriophage infecting Pseudomonas aeruginosa

    PubMed Central

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

    2016-01-01

    Bacteriophages (phages) are widely distributed in the biosphere and play a key role in modulating microbial ecology in the soil, ocean, and humans. Although the role of DNA bacteriophages is well described, the biology of RNA bacteriophages is poorly understood. More than 1900 phage genomes are currently deposited in NCBI, but only 6 dsRNA bacteriophages and 12 ssRNA bacteriophages genome sequences are reported. The 6 dsRNA bacteriophages were isolated from legume samples or lakes with Pseudomonas syringae as the host. Here, we report the first Pseudomonas aeruginosa phage phiYY with a three-segmented dsRNA genome. phiYY was isolated from hospital sewage in China with the clinical P. aeruginosa strain, PAO38, as a host. Moreover, the dsRNA phage phiYY has a broad host range, which infects 99 out of 233 clinical P. aeruginosa strains isolated from four provinces in China. This work presented a detailed characterization of the dsRNA bacteriophage infecting P. aeruginosa. PMID:27934909

  1. Role of small colony variants in persistence of Pseudomonas aeruginosa infections in cystic fibrosis lungs

    PubMed Central

    Malone, Jacob G

    2015-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that predominates during the later stages of cystic fibrosis (CF) lung infections. Over many years of chronic lung colonization, P. aeruginosa undergoes extensive adaptation to the lung environment, evolving both toward a persistent, low virulence state and simultaneously diversifying to produce a number of phenotypically distinct morphs. These lung-adapted P. aeruginosa strains include the small colony variants (SCVs), small, autoaggregative isolates that show enhanced biofilm formation, strong attachment to surfaces, and increased production of exopolysaccharides. Their appearance in the sputum of CF patients correlates with increased resistance to antibiotics, poor lung function, and prolonged persistence of infection, increasing their relevance as a subject for clinical investigation. The evolution of SCVs in the CF lung is associated with overproduction of the ubiquitous bacterial signaling molecule cyclic-di-GMP, with increased cyclic-di-GMP levels shown to be responsible for the SCV phenotype in a number of different CF lung isolates. Here, we review the current state of research in clinical P. aeruginosa SCVs. We will discuss the phenotypic characteristics underpinning the SCV morphotype, the clinical implications of lung colonization with SCVs, and the molecular basis and clinical evolution of the SCV phenotype in the CF lung environment. PMID:26251621

  2. Spatial Mapping of Pyocyanin in Pseudomonas Aeruginosa Bacterial Communities Using Surface Enhanced Raman Scattering.

    PubMed

    Polisetti, Sneha; Baig, Nameera F; Morales-Soto, Nydia; Shrout, Joshua D; Bohn, Paul W

    2017-02-01

    Surface enhanced Raman spectroscopy (SERS) imaging was used in conjunction with principal component analysis (PCA) for the in situ spatiotemporal mapping of the virulence factor pyocyanin in communities of the pathogenic bacterium Pseudomonas aeruginosa. The combination of SERS imaging and PCA analysis provides a robust method for the characterization of heterogeneous biological systems while circumventing issues associated with interference from sample autofluorescence and low reproducibility of SERS signals. The production of pyocyanin is found to depend both on the growth carbon source and on the specific strain of P. aeruginosa studied. A cystic fibrosis lung isolate strain of P. aeruginosa synthesizes and secretes pyocyanin when grown with glucose and glutamate, while the laboratory strain exhibits detectable production of pyocyanin only when grown with glutamate as the source of carbon. Pyocyanin production in the laboratory strain grown with glucose was below the limit of detection of SERS. In addition, the combination of SERS imaging and PCA can elucidate subtle differences in the molecular composition of biofilms. PCA loading plots from the clinical isolate exhibit features corresponding to vibrational bands of carbohydrates, which represent the mucoid biofilm matrix specific to that isolate, features that are not seen in the PCA loading plots of the laboratory strain.

  3. Whole Genome Analysis of 132 Clinical Saccharomyces cerevisiae Strains Reveals Extensive Ploidy Variation

    PubMed Central

    Zhu, Yuan O.; Sherlock, Gavin; Petrov, Dmitri A.

    2016-01-01

    Budding yeast has undergone several independent transitions from commercial to clinical lifestyles. The frequency of such transitions suggests that clinical yeast strains are derived from environmentally available yeast populations, including commercial sources. However, despite their important role in adaptive evolution, the prevalence of polyploidy and aneuploidy has not been extensively analyzed in clinical strains. In this study, we have looked for patterns governing the transition to clinical invasion in the largest screen of clinical yeast isolates to date. In particular, we have focused on the hypothesis that ploidy changes have influenced adaptive processes. We sequenced 144 yeast strains, 132 of which are clinical isolates. We found pervasive large-scale genomic variation in both overall ploidy (34% of strains identified as 3n/4n) and individual chromosomal copy numbers (36% of strains identified as aneuploid). We also found evidence for the highly dynamic nature of yeast genomes, with 35 strains showing partial chromosomal copy number changes and eight strains showing multiple independent chromosomal events. Intriguingly, a lineage identified to be baker’s/commercial derived with a unique damaging mutation in NDC80 was particularly prone to polyploidy, with 83% of its members being triploid or tetraploid. Polyploidy was in turn associated with a >2× increase in aneuploidy rates as compared to other lineages. This dataset provides a rich source of information on the genomics of clinical yeast strains and highlights the potential importance of large-scale genomic copy variation in yeast adaptation. PMID:27317778

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  5. Antibiotic Resistance Pattern and Evaluation of Metallo-Beta Lactamase Genes Including bla- IMP and bla- VIM Types in Pseudomonas aeruginosa Isolated from Patients in Tehran Hospitals.

    PubMed

    Aghamiri, Samira; Amirmozafari, Nour; Fallah Mehrabadi, Jalil; Fouladtan, Babak; Samadi Kafil, Hossein

    2014-01-01

    Beta-lactamase producing strains of Pseudomonas aeruginosa are important etiological agents of hospital infections. Carbapenems are among the most effective antibiotics used against Pseudomonas infections, but they can be rendered infective by group B β -lactamase, commonly called metallo-beta lactamase. In this study, the antimicrobial sensitivity patterns of P. aeruginosa strains isolated from 9 different hospitals in Tehran, Iran, as well as the prevalence of MBLs genes (bla- VIM and bla- IMP ) were determined. A total of 212 strains of P. aeruginosa recovered from patients in hospitals in Tehran were confirmed by both biochemical methods and PCR. Their antimicrobial sensitivity patterns were determined by Kirby-Bauer disk diffusion method. Following MIC determination, imipenem resistant strains were selected by DDST method which was followed by PCR tests for determination of MBLs genes: bla- IMP and bla- VIM . The results indicated that, in the DDST phenotypic method, among the 100 imipenem resistant isolates, 75 strains were MBLs positive. The PCR test indicated that 70 strains (33%) carried bla- VIM gene and 20 strains (9%) harbored bla- IMP . The results indicated that the extent of antibiotic resistance among Pseudomonas aeruginosa is on the rise. This may be due to production of MBLs enzymes. Therefore, determination of antibiotic sensitivity patterns and MBLs production by these bacteria, can be important in control of clinical Pseudomonas infection.

  6. Pseudomonas aeruginosa Pyocyanin Induces Neutrophil Death via Mitochondrial Reactive Oxygen Species and Mitochondrial Acid Sphingomyelinase

    PubMed Central

    Managò, Antonella; Becker, Katrin Anne; Carpinteiro, Alexander; Wilker, Barbara; Soddemann, Matthias; Seitz, Aaron P.; Edwards, Michael J.; Grassmé, Heike

    2015-01-01

    Abstract Aims: Pulmonary infections with Pseudomonas aeruginosa are a serious clinical problem and are often lethal. Because many strains of P. aeruginosa are resistant to antibiotics, therapeutic options are limited. Neutrophils play an important role in the host's early acute defense against pulmonary P. aeruginosa. Therefore, it is important to define the mechanisms by which P. aeruginosa interacts with host cells, particularly neutrophils. Results: Here, we report that pyocyanin, a membrane-permeable pigment and toxin released by P. aeruginosa, induces the death of wild-type neutrophils; its interaction with the mitochondrial respiratory chain results in the release of reactive oxygen species (ROS), the activation of mitochondrial acid sphingomyelinase, the formation of mitochondrial ceramide, and the release of cytochrome c from mitochondria. A genetic deficiency in acid sphingomyelinase prevents both the activation of this pathway and pyocyanin-induced neutrophil death. This reduced death, on the other hand, is associated with an increase in the release of interleukin-8 from pyocyanin-activated acid sphingomyelinase-deficient neutrophils but not from wild-type cells. Innovation: These studies identified the mechanisms by which pyocyanin induces the release of mitochondrial ROS and by which ROS induce neutrophil death via mitochondrial acid sphingomyelinase. Conclusion: These findings demonstrate a novel mechanism of pyocyanin-induced death of neutrophils and show how this apoptosis balances innate immune reactions. Antioxid. Redox Signal. 22, 1097–1110. PMID:25686490

  7. Recent advances in the treatment of Pseudomonas aeruginosa infections in cystic fibrosis

    PubMed Central

    2011-01-01

    Chronic Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) patients is caused by biofilm-growing mucoid strains. Biofilms can be prevented by early aggressive antibiotic prophylaxis or therapy, and they can be treated by chronic suppressive therapy. New results from one small trial suggest that addition of oral ciprofloxacin to inhaled tobramycin may reduce lung inflammation. Clinical trials with new formulations of old antibiotics for inhalation therapy (aztreonam lysine) against chronic P. aeruginosa infection improved patient-reported outcome, lung function, time to acute exacerbations and sputum density of P. aeruginosa. Other drugs such as quinolones are currently under investigation for inhalation therapy. A trial of the use of anti-Pseudomonas antibiotics for long-term prophylaxis showed no effect in patients who were not already infected. Use of azithromycin to treat CF patients without P. aeruginosa infection did not improve lung function. Here I review the recent advances in the treatment of P. aeruginosa lung infections with a focus on inhalation treatments targeted at prophylaxis and chronic suppressive therapy. PMID:21463524

  8. The increasing threat of Pseudomonas aeruginosa high-risk clones.

    PubMed

    Oliver, Antonio; Mulet, Xavier; López-Causapé, Carla; Juan, Carlos

    2015-01-01

    The increasing prevalence of chronic and hospital-acquired infections produced by multidrug-resistant (MDR) or extensively drug-resistant (XDR) Pseudomonas aeruginosa strains is associated with significant morbidity and mortality. This growing threat results from the extraordinary capacity of this pathogen for developing resistance through chromosomal mutations and from the increasing prevalence of transferable resistance determinants, particularly those encoding carbapenemases or extended-spectrum β-lactamases (ESBLs). P. aeruginosa has a nonclonal epidemic population structure, composed of a limited number of widespread clones which are selected from a background of a large quantity of rare and unrelated genotypes that are recombining at high frequency. Indeed, recent concerning reports have provided evidence of the existence of MDR/XDR global clones, denominated high-risk clones, disseminated in hospitals worldwide; ST235, ST111, and ST175 are likely those more widespread. Noteworthy, the vast majority of infections by MDR, and specially XDR, strains are produced by these and few other clones worldwide. Moreover, the association of high-risk clones, particularly ST235, with transferable resistance is overwhelming; nearly 100 different horizontally-acquired resistance elements and up to 39 different acquired β-lactamases have been reported so far among ST235 isolates. Likewise, MDR internationally-disseminated epidemic strains, such as the Liverpool Epidemic Strain (LES, ST146), have been noted as well among cystic fibrosis patients. Here we review the population structure, epidemiology, antimicrobial resistance mechanisms and virulence of the P. aeruginosa high-risk clones. The phenotypic and genetic factors potentially driving the success of high-risk clones, the aspects related to their detection in the clinical microbiology laboratory and the implications for infection control and public health are also discussed.

  9. In vitro antimicrobial activity on clinical microbial strains and antioxidant properties of Artemisia parviflora

    PubMed Central

    2012-01-01

    Background Artemisia parviflora leaf extracts were evaluated for potential antimicrobial and antioxidant properties. Antimicrobial susceptibility assay was performed against ten standard reference bacterial strains. Antioxidant activity was analyzed using the ferric thiocyanate and 2, 2-Diphenyl-1-Picrylhydrazyl (DPPH) assays. Radical scavenging activity and total phenolic content were compared. Phytochemical analyses were performed to identify the major bioactive constitution of the plant extract. Results Hexane, methanol and ethyl acetate extracts of A. parviflora leaves exhibited good activity against the microorganisms tested. The n-hexane extract of A. parviflora showed high inhibition of the growth of Pseudomonas aeruginosa, Escherichia coli and Shigella flexneri. Methanol extract showed strong radical scavenging and antioxidant activity, other extracts showed moderate antioxidant activity. The major derivatives present in the extracts are of terpenes, steroids, phenols, flavonoids, tannins and volatile oil. Conclusions The results obtained with n-hexane extract were particularly significant as it strongly inhibited the growth of P. aeruginosa, E. coli and S. flexneri. The major constituent of the n-hexane extract was identified as terpenes. Strong antioxidant activity could be observed with all the individual extracts. The antimicrobial and antioxidant property of the extracts were attributed to the secondary metabolites, terpenes and phenolic compounds present in A. parviflora and could be of considerable interest in the development of new drugs. PMID:23171441

  10. Pathogenic potential of Escherichia coli clinical strains from orthopedic implant infections towards human osteoblastic cells

    PubMed Central

    Crémet, Lise; Broquet, Alexis; Brulin, Bénédicte; Jacqueline, Cédric; Dauvergne, Sandie; Brion, Régis; Asehnoune, Karim; Corvec, Stéphane; Heymann, Dominique; Caroff, Nathalie

    2015-01-01

    Escherichia coli is one of the first causes of Gram-negative orthopedic implant infections (OII), but little is known about the pathogenicity of this species in such infections that are increasing due to the ageing of the population. We report how this pathogen interacts with human osteoblastic MG-63 cells in vitro, by comparing 20 OII E. coli strains to two Staphylococcus aureus and two Pseudomonas aeruginosa strains. LDH release assay revealed that 6/20 (30%) OII E. coli induced MG-63 cell lysis whereas none of the four control strains was cytotoxic after 4 h of coculture. This high cytotoxicity was associated with hemolytic properties and linked to hlyA gene expression. We further showed by gentamicin protection assay and confocal microscopy that the non-cytotoxic E. coli were not able to invade MG-63 cells unlike S. aureus strains (internalization rate <0.01% for the non-cytotoxic E. coli versus 8.88 ± 2.31% and 4.60 ± 0.42% for both S. aureus). The non-cytotoxic E. coli also demonstrated low adherence rates (<7%), the most adherent E. coli eliciting higher IL-6 and TNF-α mRNA expression in the osteoblastic cells. Either highly cytotoxic or slightly invasive OII E. coli do not show the same infection strategies as S. aureus towards osteoblasts. PMID:26333570

  11. Comparative studies on growth and physiological responses of unicellular and colonial Microcystis aeruginosa to Acorus calamus.

    PubMed

    Zhang, S-H; Chang, J-J; Cao, J-Y; Yang, C-L

    2015-02-01

    In order to explore the growth inhibition and physiological responses of unicellular and colonial Microcystis aeruginosa during coexistence with Acorus calamus, algal densities, chlorophyll a contents, exopolysaccharide (EPS) concentrations, malondialdehyde (MDA) contents, catalase (CAT) activities, and peroxidase (POD) activities of the two algae strains were analyzed. Although the unicellular and colonial strains of M. aeruginosa were both inhibited by A. calamus, unicellular algae were more sensitive than the colonial algae. The measurement results for EPS, MDA, CAT, and POD showed that unicellular M. aeruginosa had higher levels of stress related damage than colonial strains when they were exposed to the same density of A. calamus, and the cellular defense system of colonial M. aeruginosa was stronger than that of unicellular M. aeruginosa. Natural blooms of Microcystis are typically composed of colonial forms of M. aeruginosa, therefore future efforts to control such blooms, possibly through the development of new algicides, should focus on the unique characteristics of colonial M. aeruginosa strains.

  12. 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.

  13. Nonclinical and Clinical Enterococcus faecium Strains, but Not Enterococcus faecalis Strains, Have Distinct Structural and Functional Genomic Features

    PubMed Central

    Kim, Eun Bae

    2014-01-01

    Certain strains of Enterococcus faecium and Enterococcus faecalis contribute beneficially to animal health and food production, while others are associated with nosocomial infections. To determine whether there are structural and functional genomic features that are distinct between nonclinical (NC) and clinical (CL) strains of those species, we analyzed the genomes of 31 E. faecium and 38 E. faecalis strains. Hierarchical clustering of 7,017 orthologs found in the E. faecium pangenome revealed that NC strains clustered into two clades and are distinct from CL strains. NC E. faecium genomes are significantly smaller than CL genomes, and this difference was partly explained by significantly fewer mobile genetic elements (ME), virulence factors (VF), and antibiotic resistance (AR) genes. E. faecium ortholog comparisons identified 68 and 153 genes that are enriched for NC and CL strains, respectively. Proximity analysis showed that CL-enriched loci, and not NC-enriched loci, are more frequently colocalized on the genome with ME. In CL genomes, AR genes are also colocalized with ME, and VF are more frequently associated with CL-enriched loci. Genes in 23 functional groups are also differentially enriched between NC and CL E. faecium genomes. In contrast, differences were not observed between NC and CL E. faecalis genomes despite their having larger genomes than E. faecium. Our findings show that unlike E. faecalis, NC and CL E. faecium strains are equipped with distinct structural and functional genomic features indicative of adaptation to different environments. PMID:24141120

  14. Dimerization of the type IV pilin from Pseudomonas aeruginosa strain K122-4 results in increased helix stability as measured by time-resolved hydrogen-deuterium exchange

    PubMed Central

    Lento, Cristina; Wilson, Derek J.; Audette, Gerald F.

    2015-01-01

    Truncated pilin monomers from Pseudomonas aeruginosa strain K122-4 (ΔK122) have been shown to enter a monomer-dimer equilibrium in solution prior to oligomerization into protein nanotubes. Here, we examine the structural changes occurring between the monomeric and dimeric states of ΔK122 using time-resolved hydrogen-deuterium exchange mass spectrometry. Based on levels of deuterium uptake, the N-terminal α-helix and the loop connecting the second and third strands of the anti-parallel β-sheet contribute significantly to pilin dimerization. Conversely, the antiparallel β-sheet and αβ loop region exhibit increased flexibility, while the receptor binding domain retains a rigid conformation in the equilibrium state. PMID:26798830

  15. Intraclonal Genome Stability of the Metallo-β-lactamase SPM-1-producing Pseudomonas aeruginosa ST277, an Endemic Clone Disseminated in Brazilian Hospitals

    PubMed Central

    Nascimento, Ana P. B.; Ortiz, Mauro F.; Martins, Willames M. B. S.; Morais, Guilherme L.; Fehlberg, Lorena C. C.; Almeida, Luiz G. P.; Ciapina, Luciane P.; Gales, Ana C.; Vasconcelos, Ana T. R.

    2016-01-01

    Carbapenems represent the mainstay therapy for the treatment of serious P. aeruginosa infections. However, the emergence of carbapenem resistance has jeopardized the clinical use of this important class of compounds. The production of SPM-1 metallo-β-lactamase has been the most common mechanism of carbapenem resistance identified in P. aeruginosa isolated from Brazilian medical centers. Interestingly, a single SPM-1-producing P. aeruginosa clone belonging to the ST277 has been widely spread within the Brazilian territory. In the current study, we performed a next-generation sequencing of six SPM-1-producing P. aeruginosa ST277 isolates. The core genome contains 5899 coding genes relative to the reference strain P. aeruginosa PAO1. A total of 26 genomic islands were detected in these isolates. We identified remarkable elements inside these genomic islands, such as copies of the blaSPM−1 gene conferring resistance to carbapenems and a type I-C CRISPR-Cas system, which is involved in protection of the chromosome against foreign DNA. In addition, we identified single nucleotide polymorphisms causing amino acid changes in antimicrobial resistance and virulence-related genes. Together, these factors could contribute to the marked resistance and persistence of the SPM-1-producing P. aeruginosa ST277 clone. A comparison of the SPM-1-producing P. aeruginosa ST277 genomes showed that their core genome has a high level nucleotide similarity and synteny conservation. The variability observed was mainly due to acquisition of genomic islands carrying several antibiotic resistance genes. PMID:27994579

  16. Intraclonal Genome Stability of the Metallo-β-lactamase SPM-1-producing Pseudomonas aeruginosa ST277, an Endemic Clone Disseminated in Brazilian Hospitals.

    PubMed

    Nascimento, Ana P B; Ortiz, Mauro F; Martins, Willames M B S; Morais, Guilherme L; Fehlberg, Lorena C C; Almeida, Luiz G P; Ciapina, Luciane P; Gales, Ana C; Vasconcelos, Ana T R

    2016-01-01

    Carbapenems represent the mainstay therapy for the treatment of serious P. aeruginosa infections. However, the emergence of carbapenem resistance has jeopardized the clinical use of this important class of compounds. The production of SPM-1 metallo-β-lactamase has been the most common mechanism of carbapenem resistance identified in P. aeruginosa isolated from Brazilian medical centers. Interestingly, a single SPM-1-producing P. aeruginosa clone belonging to the ST277 has been widely spread within the Brazilian territory. In the current study, we performed a next-generation sequencing of six SPM-1-producing P. aeruginosa ST277 isolates. The core genome contains 5899 coding genes relative to the reference strain P. aeruginosa PAO1. A total of 26 genomic islands were detected in these isolates. We identified remarkable elements inside these genomic islands, such as copies of the blaSPM-1 gene conferring resistance to carbapenems and a type I-C CRISPR-Cas system, which is involved in protection of the chromosome against foreign DNA. In addition, we identified single nucleotide polymorphisms causing amino acid changes in antimicrobial resistance and virulence-related genes. Together, these factors could contribute to the marked resistance and persistence of the SPM-1-producing P. aeruginosa ST277 clone. A comparison of the SPM-1-producing P. aeruginosa ST277 genomes showed that their core genome has a high level nucleotide similarity and synteny conservation. The variability observed was mainly due to acquisition of genomic islands carrying several antibiotic resistance genes.

  17. Polysorbate 80 Inhibition of Pseudomonas aeruginosa Biofilm Formation and Its Cleavage by the Secreted Lipase LipA▿

    PubMed Central

    Toutain-Kidd, Christine M.; Kadivar, Samoneh C.; Bramante, Carolyn T.; Bobin, Stephen A.; Zegans, Michael E.

    2009-01-01

    Surface-associated bacterial communities known as biofilms are an important source of nosocomial infections. Microorganisms such as Pseudomonas aeruginosa can colonize the abiotic surfaces of medical implants, leading to chronic infections that are difficult to eradicate. Our study demonstrates that polysorbate 80 (PS80), a surfactant commonly added to food and medicines, is able to inhibit biofilm formation by P. aeruginosa on a variety of surfaces, including contact lenses. Many clinical isolates of P. aeruginosa, as well as gram-negative and gram-positive clinical isolates, were also inhibited in their ability to form biofilms in the presence of PS80. A P. aeruginosa mutant able to form biofilms in the presence of this surfactant was identified and characterized, and it was revealed that this mutant overexpresses a lipase, LipA. Surfactants such as PS80 can be cleaved by lipases, and we demonstrate that PS80 is cleaved by LipA at its ester bond. Finally, polyethoxylated(20) oleyl alcohol, a chemical with a structure that is similar to that of PS80 but that lacks the ester bond of PS80, can inhibit the biofilm formation of P. aeruginosa strains, including the mutant overexpressing LipA. Our results demonstrate that surfactants such as PS80 can inhibit bacterial biofilm formation on medically relevant materials at concentrations demonstrated to be safe in humans and suggest that the understanding of the mechanisms of bacterial resistance to such surfactants will be important in developing clinically effective derivatives. PMID:18955535

  18. Pseudomonas aeruginosa exopolysaccharide Psl promotes resistance to the biofilm inhibitor polysorbate 80.

    PubMed

    Zegans, Michael E; Wozniak, Daniel; Griffin, Edward; Toutain-Kidd, Christine M; Hammond, John H; Garfoot, Andrew; Lam, Joseph S

    2012-08-01

    Polysorbate 80 (PS80) is a nonionic surfactant and detergent that inhibits biofilm formation by Pseudomonas aeruginosa at concentrations as low as 0.001% and is well tolerated in human tissues. However, certain clinical and laboratory strains (PAO1) of P. aeruginosa are able to form biofilms in the presence of PS80. To better understand this resistance, we performed transposon mutagenesis with a PS80-resistant clinical isolate, PA738. This revealed that mutation of algC rendered PA738 sensitive to PS80 biofilm inhibition. AlgC contributes to the biosynthesis of the exopolysaccharides Psl and alginate, as well as lipopolysaccharide and rhamnolipid. Analysis of mutations downstream of AlgC in these biosynthetic pathways established that disruption of the psl operon was sufficient to render the PA738 and PAO1 strains sensitive to PS80-mediated biofilm inhibition. Increased levels of Psl production in the presence of arabinose in a strain with an arabinose-inducible psl promoter were correlated with increased biofilm formation in PS80. In P. aeruginosa strains MJK8 and ZK2870, known to produce both Pel and Psl, disruption of genes in the psl but not the pel operon conferred susceptibility to PS80-mediated biofilm inhibition. The laboratory strain PA14 does not produce Psl and does not form biofilms in PS80. However, when PA14 was transformed with a cosmid containing the psl operon, it formed biofilms in the presence of PS80. Taken together, these data suggest that production of the exopolysaccharide Psl by P. aeruginosa promotes resistance to the biofilm inhibitor PS80.

  19. Molecular Typing of Environmental and Clinical Strains of Vibrio vulnificus Isolated in the Northeastern USA

    PubMed Central

    Reynaud, Yann; Pitchford, Steven; De Decker, Sophie; Wikfors, Gary H.; Brown, Christopher L.

    2013-01-01

    Vibrio vulnificus is a ubiquitous marine bacterium that is responsible for infections and some seafood-related illnesses and deaths in the United States, mainly in individuals with compromised health status in the Gulf of Mexico region. Most phylogenetic studies focus on V. vulnificus strains isolated in the southern United States, but almost no genetic data are available on northeastern bacterial isolates of clinical or environmental origin. Our goal in this study was to examine the genetic diversity of environmental strains isolated from commercially-produced oysters and in clinical strains of known pathogenicity in northeastern United States. We conducted analyses of a total of eighty-three strains of V. vulnificus, including 18 clinical strains known to be pathogenic. A polyphasic, molecular-typing approach was carried out, based upon established biotypes, vcg, CPS, 16S rRNA types and three other genes possibly associated with virulence (arylsulfatase A, mtlABC, and nanA). An established Multi Locus Sequence Typing (MLST) method was also performed. Phylogenetic analyses of these markers and MLST results produced similar patterns of clustering of strains into two main lineages (we categorized as ‘LI’ and ‘LII’), with clinical and environmental strains clustering together in both lineages. Lineage LII was comprised primarily but not entirely of clinical bacterial isolates. Putative virulence markers were present in both clinical and environmental strains. These results suggest that some northeastern environmental strains of V. vulnificus are phylogenetically close to clinical strains and probably are capable of virulence. Further studies are necessary to assess the risk of human illness from consuming raw oysters harvested in the northeastern US. PMID:24386187

  20. Molecular typing of environmental and clinical strains of Vibrio vulnificus isolated in the northeastern USA.

    PubMed

    Reynaud, Yann; Pitchford, Steven; De Decker, Sophie; Wikfors, Gary H; Brown, Christopher L

    2013-01-01

    Vibrio vulnificus is a ubiquitous marine bacterium that is responsible for infections and some seafood-related illnesses and deaths in the United States, mainly in individuals with compromised health status in the Gulf of Mexico region. Most phylogenetic studies focus on V. vulnificus strains isolated in the southern United States, but almost no genetic data are available on northeastern bacterial isolates of clinical or environmental origin. Our goal in this study was to examine the genetic diversity of environmental strains isolated from commercially-produced oysters and in clinical strains of known pathogenicity in northeastern United States. We conducted analyses of a total of eighty-three strains of V. vulnificus, including 18 clinical strains known to be pathogenic. A polyphasic, molecular-typing approach was carried out, based upon established biotypes, vcg, CPS, 16S rRNA types and three other genes possibly associated with virulence (arylsulfatase A, mtlABC, and nanA). An established Multi Locus Sequence Typing (MLST) method was also performed. Phylogenetic analyses of these markers and MLST results produced similar patterns of clustering of strains into two main lineages (we categorized as 'LI' and 'LII'), with clinical and environmental strains clustering together in both lineages. Lineage LII was comprised primarily but not entirely of clinical bacterial isolates. Putative virulence markers were present in both clinical and environmental strains. These results suggest that some northeastern environmental strains of V. vulnificus are phylogenetically close to clinical strains and probably are capable of virulence. Further studies are necessary to assess the risk of human illness from consuming raw oysters harvested in the northeastern US.

  1. [The experience of implementation of REP-u RAPD-polymerase chain reaction in epidemiologic characteristic of nosocomial isolates Pseudomonas aeruginosa].

    PubMed

    Kuznetsova, M V; Maksimova, A V; Karpunina, T I

    2015-03-01

    The article presents comparative evaluation of diagnostic value of technique REP- u RAPD-polymerase chain reaction applied under genetic typing of clinical isolates of Pseudomonas Aeruginosa. The strains are isolated in different hospital departments of medical institutions in adult (8 medical institutions; n = 145) and children (5 medical institutions; n = 151) medical networks. The results of study demonstrated different boundary capacity of three reactions. The Simpson discrimination index made up to 0.993, 0.875 and 0.639 for RAPD-, ERIC- and BOX-polymerase chain reaction correspondingly. The RAPD-polymerase chain reaction makes it possible to detect individual characteristics of strains. Out of two alternatives the REP-polymerase chain reaction demonstrated its advantage, besides only with one primer ERIC2. The BOX-polymerase chain reaction has a least discriminating capacity under typing of isolates P. aeruginosa, detecting only species' characteristics. The clinical strains P. aeruginosa are distributed on 24 genome groups and 52 isolates had individual genotypes. The evaluation of results of genetic typing permitted to point out both similarity of tendencies in propagation of strains of P. aeruginosa among hospitalized adults and adolescents and specificity of detection in neonatal clinics. It is obvious that hospitals of different profiles, including departments of reanimation and intensive therapy represent specific ecological environment significantly different in its level of endogenous and exogenous infection.

  2. Pseudomonas aeruginosa: breaking down barriers.

    PubMed

    Berube, Bryan J; Rangel, Stephanie M; Hauser, Alan R

    2016-02-01

    Many bacterial pathogens have evolved ingenious ways to escape from the lung during pneumonia to cause bacteremia. Unfortunately, the clinical consequences of this spread to the bloodstream are frequently dire. It is therefore important to understand the molecular mechanisms used by pathogens to breach the lung barrier. We have recently shown that Pseudomonas aeruginosa, one of the leading causes of hospital-acquired pneumonia, utilizes the type III secretion system effector ExoS to intoxicate pulmonary epithelial cells. Injection of these cells leads to localized disruption of the pulmonary-vascular barrier and dissemination of P. aeruginosa to the bloodstream. We put these data in the context of previous studies to provide a holistic model of P. aeruginosa dissemination from the lung. Finally, we compare P. aeruginosa dissemination to that of other bacteria to highlight the complexity of bacterial pneumonia. Although respiratory pathogens use distinct and intricate strategies to escape from the lungs, a thorough understanding of these processes can lay the foundation for new therapeutic approaches for bacterial pneumonia.

  3. Cryptic transposable phages of Pseudomonas aeruginosa

    SciTech Connect

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

    1995-11-01

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

  4. Response to Gaseous NO2 Air Pollutant of P. fluorescens Airborne Strain MFAF76a and Clinical Strain MFN1032

    PubMed Central

    Kondakova, Tatiana; Catovic, Chloé; Barreau, Magalie; Nusser, Michael; Brenner-Weiss, Gerald; Chevalier, Sylvie; Dionnet, Frédéric; Orange, Nicole; Poc, Cécile Duclairoir

    2016-01-01

    Human exposure to nitrogen dioxide (NO2), an air pollutant of increasing interest in biology, results in several toxic effects to human health and also to the air microbiota. The aim of this study was to investigate the bacterial response to gaseous NO2. Two Pseudomonas fluorescens strains, namely the airborne strain MFAF76a and the clinical strain MFN1032 were exposed to 0.1, 5, or 45 ppm concentrations of NO2, and their effects on bacteria were evaluated in terms of motility, biofilm formation, antibiotic resistance, as well as expression of several chosen target genes. While 0.1 and 5 ppm of NO2did not lead to any detectable modification in the studied phenotypes of the two bacteria, several alterations were observed when the bacteria were exposed to 45 ppm of gaseous NO2. We thus chose to focus on this high concentration. NO2-exposed P. fluorescens strains showed reduced swimming motility, and decreased swarming in case of the strain MFN1032. Biofilm formed by NO2-treated airborne strain MFAF76a showed increased maximum thickness compared to non-treated cells, while NO2 had no apparent effect on the clinical MFN1032 biofilm structure. It is well known that biofilm and motility are inversely regulated by intracellular c-di-GMP level. The c-di-GMP level was however not affected in response to NO2 treatment. Finally, NO2-exposed P. fluorescens strains were found to be more resistant to ciprofloxacin and chloramphenicol. Accordingly, the resistance nodulation cell division (RND) MexEF-OprN efflux pump encoding genes were highly upregulated in the two P. fluorescens strains. Noticeably, similar phenotypes had been previously observed following a NO treatment. Interestingly, an hmp-homolog gene in P. fluorescens strains MFAF76a and MFN1032 encodes a NO dioxygenase that is involved in NO detoxification into nitrites. Its expression was upregulated in response to NO2, suggesting a possible common pathway between NO and NO2 detoxification. Taken together, our study

  5. First report of VIM-2 metallo-β-lactamases producing Pseudomonas aeruginosa isolates in Morocco.

    PubMed

    Maroui, Itto; Barguigua, Abouddihaj; Aboulkacem, Asmae; Ouarrak, Khadija; Sbiti, Mohammed; Louzi, Housssain; Timinouni, Mohammed; Belhaj, Abdelhaq

    2016-03-01

    The emergence and the rapid spread of Pseudomonas aeruginosa carrying carbapenemases represent a serious threat to public health due to their delicate therapy. This work was performed to establish the resistance profile and to detect carbapenemases producing in 123 P. aeruginosa isolates. Among these 55 are environmental isolates and 68 are from the two major hospitals of Meknes-Tafilalet region in Morocco. All strains were tested against 14 antipseudomonal drugs by disc diffusion method. On carbapenem resistant strains minimum inhibitory concentrations of imipenem were determined by the E-test method. The modified Hodge test and EDTA tests were used for the detection of carbapenemases and metallo-β-lactamases (MBLs), respectively. PCR and DNA sequencing were conducted to detect carbapenemase-encoding genes and the enzyme types. 12% of isolates was susceptible to all antibiotics tested and Carbapenem resistance was observed in 33 P. aeruginosa isolates, 33.3% of them were multi-drug resistant. Among carbapenem resistant strains only two (6.1%) were positive for carbapenemases and also for MBLs. In addition to their resistance to almost all β-lactams tested, the MBLs producing strains were resistant to aminoglycosides. Molecular biology techniques confirmed the phenotypic results obtained for the two strains carbapenemase producers and demonstrated that each one of them carried blaVIM-2. The present study reports the first isolation of blaVIM genes in clinical isolates of P. aeruginosa in Morocco. Such isolates represent a serious emerging threat requiring strict hygiene measures to better control their spread.

  6. Berberine Is a Novel Type Efflux Inhibitor Which Attenuates the MexXY-Mediated Aminoglycoside Resistance in Pseudomonas aeruginosa

    PubMed Central

    Morita, Yuji; Nakashima, Ken-ichi; Nishino, Kunihiko; Kotani, Kenta; Tomida, Junko; Inoue, Makoto; Kawamura, Yoshiaki

    2016-01-01

    The emergence and spread of multidrug-resistant P. aeruginosa infections is of great concern, as very few agents are effective against strains of this species. Methanolic extracts from the Coptidis Rhizoma (the rhizomes of Coptis japonica var. major Satake) or Phellodendri Cortex (the bark of Phellodendron chinense Schneider) markedly reduced resistance to anti-pseudomonal aminoglycosides (e.g., amikacin) in multidrug-resistant P. aeruginosa strains. Berberine, the most abundant benzylisoquinoline alkaloid in the two extracts, reduced aminoglycoside resistance of P. aeruginosa via a mechanism that required the MexXY multidrug efflux system; berberine also reduced aminoglycoside MICs in Achromobacter xylosoxidans and Burkholderia cepacia, two species that harbor intrinsic multidrug efflux systems very similar to the MexXY. Furthermore this compound inhibited MexXY-dependent antibiotic resistance of other classes including cephalosporins (cefepime), macrolides (erythromycin), and lincosamides (lincomycin) demonstrated using a pseudomonad lacking the four other major Mex pumps. Although phenylalanine-arginine beta-naphthylamide (PAβN), a well-known efflux inhibitor, antagonized aminoglycoside in a MexXY-dependent manner, a lower concentration of berberine was sufficient to reduce amikacin resistance of P. aeruginosa in the presence of PAβN. Moreover, berberine enhanced the synergistic effects of amikacin and piperacillin (and vice versa) in multidrug-resistant P. aeruginosa strains. Thus, berberine appears to be a novel type inhibitor of the MexXY-dependent aminoglycoside efflux in P. aeruginosa. As aminoglycosides are molecules of choice to treat severe infections the clinical impact is potentially important. PMID:27547203

  7. Type IV pilus glycosylation mediates resistance of Pseudomonas aeruginosa to opsonic activities of the pulmonary surfactant protein A.

    PubMed

    Tan, Rommel M; Kuang, Zhizhou; Hao, Yonghua; Lee, Francis; Lee, Timothy; Lee, Ryan J; Lau, Gee W

    2015-04-01

    Pseudomonas aeruginosa is a major bacterial pathogen commonly associated with chronic lung infections in cystic fibrosis (CF). Previously, we have demonstrated that the type IV pilus (Tfp) of P. aeruginosa mediates resistance to antibacterial effects of pulmonary surfactant protein A (SP-A). Interestingly, P. aeruginosa strains with group I pilins are O-glycosylated through the TfpO glycosyltransferase with a single subunit of O-antigen (O-ag). Importantly, TfpO-mediated O-glycosylation is important for virulence in mouse lungs, exemplified by more frequent lung infection in CF with TfpO-expressing P. aeruginosa strains. However, the mechanism underlying the importance of Tfp glycosylation in P. aeruginosa pathogenesis is not fully understood. Here, we demonstrated one mechanism of increased fitness mediated by O-glycosylation of group 1 pilins on Tfp in the P. aeruginosa clinical isolate 1244. Using an acute pneumonia model in SP-A+/+ versus SP-A-/- mice, the O-glycosylation-deficient ΔtfpO mutant was found to be attenuated in lung infection. Both 1244 and ΔtfpO strains showed equal levels of susceptibility to SP-A-mediated membrane permeability. In contrast, the ΔtfpO mutant was more susceptible to opsonization by SP-A and by other pulmonary and circulating opsonins, SP-D and mannose binding lectin 2, respectively. Importantly, the increased susceptibility to phagocytosis was abrogated in the absence of opsonins. These results indicate that O-glycosylation of Tfp with O-ag specifically confers resistance to opsonization during host-mediated phagocytosis.

  8. A dual-strain feline calicivirus vaccine stimulates broader cross-neutralization antibodies than a single-strain vaccine and lessens clinical signs in vaccinated cats when challenged with a homologous feline calicivirus strain associated with virulent systemic disease.

    PubMed

    Huang, Chengjin; Hess, Jennifer; Gill, Michael; Hustead, David

    2010-02-01

    Feline calicivirus (FCV) causes an array of clinical disease in cats. Traditionally this disease has been associated with respiratory disease, limping, or chronic stomatitis. Within the last 10 years, virulent systemic feline calicivirus (VS-FCV) has been recognized which causes additional clinical signs and has a higher fatality rate. A dual-strain FCV vaccine containing a strain of FCV associated with traditional respiratory disease and a VS-FCV strain stimulates serum cross-neutralization antibodies when tested against field strains from Europe and VS-FCV strains from USA. Following challenge with a homologous VS-FCV strain, vaccinated cats had significantly reduced clinical signs.

  9. Stably luminescent Staphylococcus aureus clinical strains for use in bioluminescent imaging.

    PubMed

    Plaut, Roger D; Mocca, Christopher P; Prabhakara, Ranjani; Merkel, Tod J; Stibitz, Scott

    2013-01-01

    In vivo bioluminescent imaging permits the visualization of bacteria in live animals, allowing researchers to monitor, both temporally and spatially, the progression of infection in each animal. We sought to engineer stably luminescent clinical strains of Staphylococcus aureus, with the goal of using such strains in mouse models. The gram-positive shuttle vector pMAD was used as the backbone for an integration plasmid. A chloramphenicol resistance gene, a modified lux operon from Photorhabdus luminescens, and approximately 650 bp of homology to the chromosome of the USA300 S. aureus strain NRS384 were added, generating plasmid pRP1195. Electroporation into strain RN4220 followed by temperature shift led to integration of pRP1195 into the chromosome. The integrated plasmid was transferred to clinical strains by phage transduction. Luminescent strains displayed no in vitro growth defects. Moreover, luminescence was stable in vitro after three rounds of subculture over 48 hours of growth in the absence of antibiotics. Mice were infected with a luminescent strain of NRS384 in skin and intravenous models. In a mouse skin model, luminescent bacteria were present in lesions that formed and cleared over the course of several days, and in an intravenous model, bacteria inoculated in the mouse tail vein were observed spreading to multiple tissues. No statistically significant difference in virulence was observed between NRS384 and the luminescent strain in either infection model. These preliminary data suggest that this luminescent USA300 strain is suitable for use in mouse models. Similar strains were engineered using other sequenced clinical strains. Because these strains are stably luminescent, they should prove useful in animal models of infection.

  10. Repression of common bull sperm flora and in vitro impairment of sperm motility with Pseudomonas aeruginosa introduced by contaminated lubricant.

    PubMed

    Smole, I; Thomann, A; Frey, J; Perreten, V

    2010-08-01

    Semen collected from clinically healthy bulls at an artificial insemination centre was examined for bacterial diversity. While bacteria that are normally present in the common flora of bovine semen were absent, such as Mycoplasma sp., Proteus sp. and Corynebacterium sp., all semen samples contained an unusually high number of Pseudomonas aeruginosa strains. Analysis via pulsed field gel electrophoresis demonstrated that one particular P. aeruginosa strain, present in a sealed bottle of lubricant, was widespread in bull semen. This strain was shown to secrete substances that inhibited both the growth of bacteria constituting the normal bull sperm flora and the motility of spermatozoa in vitro. This study demonstrated that commercially available lubricants might contain bacteria that can spread amongst breeding bulls and affect the quality of semen. Bacteriological controls and species' identification are necessary at several production levels, including lubricants and extenders, to ensure high semen quality and avoid the spread of pathogens.

  11. Phenotypic and Genotypic Characterization of Pediococcus Strains Isolated from Human Clinical Sources

    PubMed Central

    Barros, Rosana R.; Carvalho, Maria Da Glória S.; Peralta, José Mauro; Facklam, Richard R.; Teixeira, Lúcia M.

    2001-01-01

    Seventy-two strains of pediococci isolated from human clinical sources were characterized by conventional physiological tests, chromogenic enzymatic tests, analysis of whole-cell protein profiles (WCPP) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and analysis of chromosomal DNA restriction profiles by pulsed-field gel electrophoresis (PFGE). Conventional tests allowed identification of 67 isolates: 52 strains were identified as Pediococcus acidilactici, 15 strains were identified as Pediococcus pentosaceus, and 5 strains were not identified because of atypical reactions. Analysis of WCPP identified all isolates since each species had a unique WCPP. By the WCPP method, the atypical strains were identified as P. acidilactici (two strains) and P. pentosaceus (three strains). The chromogenic substrate test with o-nitrophenyl-β-d-glucopyranoside differentiated all 54 strains of P. acidilactici (negative reactions) and 13 (72%) of 18 strains of P. pentosaceus (positive reactions). Isolates of both species were shown to be nonclonal as revealed by the genetic diversity when chromosomal DNA was analyzed by PFGE. Using WCPP as the definitive identification procedure, P. acidilactici (28 of 54 strains; 51.8%) was more likely than P. pentosaceus (4 of 18 strains; 22.3%) to be isolated from blood cultures. PMID:11283035

  12. Colistin-Resistant Acinetobacter baumannii Clinical Strains with Deficient Biofilm Formation

    PubMed Central

    Dafopoulou, Konstantina; Xavier, Basil Britto; Hotterbeekx, An; Janssens, Lore; Lammens, Christine; Dé, Emmanuelle; Goossens, Herman; Tsakris, Athanasios; Malhotra-Kumar, Surbhi

    2015-01-01

    In two pairs of clinical colistin-susceptible/colistin-resistant (Csts/Cstr) Acinetobacter baumannii strains, the Cstr strains showed significantly decreased biofilm formation in static and dynamic assays (P < 0.001) and lower relative fitness (P < 0.05) compared with those of the Csts counterparts. The whole-genome sequencing comparison of strain pairs identified a mutation converting a stop codon to lysine (*241K) in LpsB (involved in lipopolysaccharide [LPS] synthesis) in one Cstr strain and a frameshift mutation in CarO and the loss of a 47,969-bp element containing multiple genes associated with biofilm production in the other. PMID:26666921

  13. Effects of Silver Nanoparticles on Multiple Drug-Resistant Strains of Staphylococcus aureus and Pseudomonas aeruginosa from Mastitis-Infected Goats: An Alternative Approach for Antimicrobial Therapy.

    PubMed

    Yuan, Yu-Guo; Peng, Qiu-Ling; Gurunathan, Sangiliyandi

    2017-03-06

    Recently, silver nanoparticles (AgNPs) have been widely used in various applications as antimicrobial agents, anticancer, diagnostics, biomarkers, cell labels, and drug delivery systems for the treatment of various diseases. Microorganisms generally acquire resistance to antibiotics through the course of antibacterial therapy. Multi-drug resistance (MDR) has become a growing problem in the treatment of infectious diseases, and the widespread use of broad-spectrum antibiotics has resulted in the development of antibiotic resistance by numerous human and animal bacterial pathogens. As a result, an increasing number of microorganisms are resistant to multiple antibiotics causing continuing economic losses in dairy farming. Therefore, there is an urgent need for the development of alternative, cost-effective, and efficient antimicrobial agents that overcome antimicrobial resistance. Here, AgNPs synthesized using the bio-molecule quercetin were characterized using various analytical techniques. The synthesized AgNPs were highly spherical in shape and had an average size of 11 nm. We evaluated the efficacy of synthesized AgNPs against two MDR pathogenic bacteria, namely, Pseudomonas aeruginosa and Staphylococcus aureus, which were isolated from milk samples produced by mastitis-infected goats. The minimum inhibitory concentrations (MICs) of AgNPs against P. aeruginosa and S. aureus were found to be 1 and 2 μg/mL, respectively. Our findings suggest that AgNPs exert antibacterial effects in a dose- and time-dependent manner. Results from the present study demonstrate that the antibacterial activity of AgNPs is due to the generation of reactive oxygen species (ROS), malondialdehyde (MDA), and leakage of proteins and sugars in bacterial cells. Results of the present study showed that AgNP-treated bacteria had significantly lower lactate dehydrogenase activity (LDH) and lower adenosine triphosphate (ATP) levels compared to the control. Furthermore, AgNP-treated bacteria

  14. Effects of Silver Nanoparticles on Multiple Drug-Resistant Strains of Staphylococcus aureus and Pseudomonas aeruginosa from Mastitis-Infected Goats: An Alternative Approach for Antimicrobial Therapy

    PubMed Central

    Yuan, Yu-Guo; Peng, Qiu-Ling; Gurunathan, Sangiliyandi

    2017-01-01

    Recently, silver nanoparticles (AgNPs) have been widely used in various applications as antimicrobial agents, anticancer, diagnostics, biomarkers, cell labels, and drug delivery systems for the treatment of various diseases. Microorganisms generally acquire resistance to antibiotics through the course of antibacterial therapy. Multi-drug resistance (MDR) has become a growing problem in the treatment of infectious diseases, and the widespread use of broad-spectrum antibiotics has resulted in the development of antibiotic resistance by numerous human and animal bacterial pathogens. As a result, an increasing number of microorganisms are resistant to multiple antibiotics causing continuing economic losses in dairy farming. Therefore, there is an urgent need for the development of alternative, cost-effective, and efficient antimicrobial agents that overcome antimicrobial resistance. Here, AgNPs synthesized using the bio-molecule quercetin were characterized using various analytical techniques. The synthesized AgNPs were highly spherical in shape and had an average size of 11 nm. We evaluated the efficacy of synthesized AgNPs against two MDR pathogenic bacteria, namely, Pseudomonas aeruginosa and Staphylococcus aureus, which were isolated from milk samples produced by mastitis-infected goats. The minimum inhibitory concentrations (MICs) of AgNPs against P. aeruginosa and S. aureus were found to be 1 and 2 μg/mL, respectively. Our findings suggest that AgNPs exert antibacterial effects in a dose- and time-dependent manner. Results from the present study demonstrate that the antibacterial activity of AgNPs is due to the generation of reactive oxygen species (ROS), malondialdehyde (MDA), and leakage of proteins and sugars in bacterial cells. Results of the present study showed that AgNP-treated bacteria had significantly lower lactate dehydrogenase activity (LDH) and lower adenosine triphosphate (ATP) levels compared to the control. Furthermore, AgNP-treated bacteria

  15. ISPa46, a novel insertion sequence in the oprD porin gene of an imipenem-resistant Pseudomonas aeruginosa isolate from a cystic fibrosis patient in Marseille, France.

    PubMed

    Diene, Seydina M; L'homme, Tiphanie; Bellulo, Sophia; Stremler, Nathalie; Dubus, Jean-Christophe; Mely, Laurent; Leroy, Sylvie; Degand, Nicolas; Rolain, Jean-Marc

    2013-09-01

    Clinical isolates of Pseudomonas aeruginosa exhibiting high-level resistance to carbapenems were recovered from a French patient with cystic fibrosis (CF) who had not received carbapenem therapy. This study was conducted to investigate the molecular mechanism conferring the carbapenem-resistant phenotype in clinical isolates of P. aeruginosa recovered from the same CF patient chronically colonised since 2005. Investigation of imipenem resistance of P. aeruginosa strain_02 isolated in May 2011 showed no carbapenemase activity. However, amplification and sequencing of the oprD porin gene revealed disruption of this gene by an insertion sequence (IS) element of 1337 bp that contained a novel transposase of 1227 bp (ISPa46) bordered by two terminal imperfect inverted repeats of 28 bp, which was associated with carbapenem resistance. Retrospective analysis of five additional strains of P. aeruginosa isolated before May 2011 from the same patient revealed that all isolates were likely to be the same clone by multilocus sequence typing analysis (ST540/551), but one of the five isolates was imipenem-susceptible. Although it was possible to demonstrate the presence of ISPa46 in all strains by PCR, this IS was transposed in the oprD gene only for imipenem-resistant isolates. Therefore, this study reports a novel IS element (ISPa46) in P. aeruginosa clinical isolates of a CF patient in Marseille, France, that was associated with carbapenem resistance and was selected in the absence of carbapenem treatment.

  16. Rapid detection of Pseudomonas aeruginosa biomarkers in biological fluids using surface-enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Wu, Xiaomeng; Chen, Jing; Zhao, Yiping; Zughaier, Susu M.

    2014-05-01

    Pseudomonas aeruginosa (PA) is an opportunistic pathogen that causes major infection not only in Cystic Fibrosis patients but also in chronic obstructive pulmonary disease and in critically ill patients in intensive care units. Successful antibiotic treatment of the infection relies on accurate and rapid identification of the infectious agents. Conventional microbiological detection methods usually take more than 3 days to obtain accurate results. We have developed a rapid diagnostic technique based on surface-enhanced Raman scattering to directly identify PA from biological fluids. P. aeruginosa strains, PAO1 and PA14, are cultured in lysogeny broth, and the SERS spectra of the broth show the signature Raman peaks from pyocyanin and pyoverdine, two major biomarkers that P. aeruginosa secretes during its growth, as well as lipopolysaccharides. This provides the evidence that the presence of these biomarkers can be used to indicate P. aeruginosa infection. A total of 22 clinical exhaled breath condensates (EBC) samples were obtained from subjects with CF disease and from non-CF healthy donors. SERS spectra of these EBC samples were obtained and further analyzed by both principle component analysis and partial least square-discriminant analysis (PLS-DA). PLS-DA can discriminate the samples with P. aeruginosa infection and the ones without P. aeruginosa infection at 99.3% sensitivity and 99.6% specificity. In addition, this technique can also discriminate samples from subject with CF disease and healthy donor with 97.5% sensitivity and 100% specificity. These results demonstrate the potential of using SERS of EBC samples as a rapid diagnostic tool to detect PA infection.

  17. Requirements for Pseudomonas aeruginosa acute burn and chronic surgical wound infection.

    PubMed

    Turner, Keith H; Everett, Jake; Trivedi, Urvish; Rumbaugh, Kendra P; Whiteley, Marvin

    2014-07-01

    Opportunistic infections caused by Pseudomonas aeruginosa can be acute or chronic. While acute infections often spread rapidly and can cause tissue damage and sepsis with high mortality rates, chronic infections can persist for weeks, months, or years in the face of intensive clinical intervention. Remarkably, this diverse infectious capability is not accompanied by extensive variation in genomic content, suggesting that the genetic capacity to be an acute or a chronic pathogen is present in most P. aeruginosa strains. To investigate the genetic requirements for acute and chronic pathogenesis in P. aeruginosa infections, we combined high-throughput sequencing-mediated transcriptome profiling (RNA-seq) and genome-wide insertion mutant fitness profiling (Tn-seq) to characterize gene expression and fitness determinants in murine models of burn and non-diabetic chronic wound infection. Generally we discovered that expression of a gene in vivo is not correlated with its importance for fitness, with the exception of metabolic genes. By combining metabolic models generated from in vivo gene expression data with mutant fitness profiles, we determined the nutritional requirements for colonization and persistence in these infections. Specifically, we found that long-chain fatty acids represent a major carbon source in both chronic and acute wounds, and P. aeruginosa must biosynthesize purines, several amino acids, and most cofactors during infection. In addition, we determined that P. aeruginosa requires chemotactic flagellar motility for fitness and virulence in acute burn wound infections, but not in non-diabetic chronic wound infections. Our results provide novel insight into the genetic requirements for acute and chronic P. aeruginosa wound infections and demonstrate the power of using both gene expression and fitness profiling for probing bacterial virulence.

  18. Characterization of the medium- and long-chain n-alkanes degrading Pseudomonas aeruginosa strain SJTD-1 and its alkane hydroxylase genes.

    PubMed

    Liu, Huan; Xu, Jing; Liang, Rubing; Liu, Jianhua

    2014-01-01

    A gram-negative aliphatic hydrocarbon-degrading bacterium SJTD-1 isolated from oil-contaminated soil was identified as Pseudomonas aeruginosa by comparative analyses of the 16S rRNA sequence, phenotype, and physiological features. SJTD-1 could efficiently mineralize medium- and long-chain n-alkanes (C12-C30) as its sole carbon source within seven days, showing the most optimal growth on n-hexadecane, followed by n-octadecane, and n-eicosane. In 36 h, 500 mg/L of tetradecane, hexadecane, and octadecane were transformed completely; and 2 g/L n-hexadecane was degraded to undetectable levels within 72 h. Two putative alkane-degrading genes (gene 3623 and gene 4712) were characterized and our results indicated that their gene products were rate-limiting enzymes involved in the synergetic catabolism of C12-C16 alkanes. On the basis of bioinformatics and transcriptional analysis, two P450 monooxygenases, along with a putative AlmA-like oxygenase, were examined. Genetically defective mutants lacking the characteristic alkane hydroxylase failed to degrade n-octadecane, thereby suggesting a different catalytic mechanism for the microbial transformation of alkanes with chain lengths over C18.

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

    PubMed Central

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

    2015-01-01

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

  20. Effect of bacterial inoculation of strains of Pseudomonas aeruginosa, Alcaligenes feacalis and Bacillus subtilis on germination, growth and heavy metal (Cd, Cr, and Ni) uptake of Brassica juncea.

    PubMed

    Ndeddy Aka, Robinson Junior; Babalola, Olubukola Oluranti

    2016-01-01

    Bacterial inoculation may influence Brassica juncea growth and heavy metal (Ni, Cr, and Cd) accumulation. Three metal tolerant bacterial isolates (BCr3, BCd33, and BNi11) recovered from mine tailings, identified as Pseudomonas aeruginosa KP717554, Alcaligenes feacalis KP717561, and Bacillus subtilis KP717559 were used. The isolates exhibited multiple plant growth beneficial characteristics including the production of indole-3-acetic acid, hydrogen cyanide, ammonia, insoluble phosphate solubilization together with the potential to protect plants against fungal pathogens. Bacterial inoculation improved seeds germination of B. juncea plant in the presence of 0.1 mM Cr, Cd, and Ni, as compared to the control treatment. Compared with control treatment, soil inoculation with bacterial isolates significantly increased the amount of soluble heavy metals in soil by 51% (Cr), 50% (Cd), and 44% (Ni) respectively. Pot experiment of B. juncea grown in soil spiked with 100 mg kg(-1) of NiCl2, 100 mg kg(-1) of CdCl2, and 150 mg kg(-1) of K2Cr2O7, revealed that inoculation with metal tolerant bacteria not only protected plants against the toxic effects of heavy metals, but also increased growth and metal accumulation of plants significantly. These findings suggest that such metal tolerant, plant growth promoting bacteria are valuable tools which could be used to develop bio-inoculants for enhancing the efficiency of phytoextraction.

  1. Mechanism of resistance to benzalkonium chloride by Pseudomonas aeruginosa.

    PubMed

    Sakagami, Y; Yokoyama, H; Nishimura, H; Ose, Y; Tashima, T

    1989-08-01

    The mechanisms of resistance of Pseudomonas aeruginosa to benzalkonium chloride (BC) were studied. The effluence of cell components was observed in susceptible P. aeruginosa by electron microscopy, but resistant P. aeruginosa seemed to be undamaged. No marked changes in cell surface potential between Escherichia coli NIHJC-2 and a spheroplast strain were found. The contents of phospholipids (PL) and fatty and neutral lipids (FNL) in the cell walls of resistant P. aeruginosa were higher than those in the cell walls of susceptible P. aeruginosa. The amounts of BC adsorbed to PL and FNL of cell walls of BC-resistant P. aeruginosa were lower than those for BC-susceptible P. aeruginosa. Fifteen species of cellular fatty acids were identified by capillary gas chromatography and gas chromatography-mass spectrometry. The ability of BC to permeate the cell wall was reduced because of the increase in cellular fatty acids. These results suggested that the resistance of P. aeruginosa to BC is mainly a result of increased in the contents of PL and FNL. In resistant P. aeruginosa, the decrease in the amount of BC adsorbed is likely to be the result of increases in the contents of PL and FNL.

  2. Mechanism of resistance to benzalkonium chloride by Pseudomonas aeruginosa.

    PubMed Central

    Sakagami, Y; Yokoyama, H; Nishimura, H; Ose, Y; Tashima, T

    1989-01-01

    The mechanisms of resistance of Pseudomonas aeruginosa to benzalkonium chloride (BC) were studied. The effluence of cell components was observed in susceptible P. aeruginosa by electron microscopy, but resistant P. aeruginosa seemed to be undamaged. No marked changes in cell surface potential between Escherichia coli NIHJC-2 and a spheroplast strain were found. The contents of phospholipids (PL) and fatty and neutral lipids (FNL) in the cell walls of resistant P. aeruginosa were higher than those in the cell walls of susceptible P. aeruginosa. The amounts of BC adsorbed to PL and FNL of cell walls of BC-resistant P. aeruginosa were lower than those for BC-susceptible P. aeruginosa. Fifteen species of cellular fatty acids were identified by capillary gas chromatography and gas chromatography-mass spectrometry. The ability of BC to permeate the cell wall was reduced because of the increase in cellular fatty acids. These results suggested that the resistance of P. aeruginosa to BC is mainly a result of increased in the contents of PL and FNL. In resistant P. aeruginosa, the decrease in the amount of BC adsorbed is likely to be the result of increases in the contents of PL and FNL. Images PMID:2506813

  3. Antibacterial Honey (Medihoney™): in-vitro Activity Against Clinical Isolates of MRSA, VRE, and Other Multiresistant Gram-negative Organisms Including Pseudomonas aeruginosa.

    PubMed

    George, Narelle May; Cutting, Keith F

    2007-09-01

    The clinical use of honey has received increasing interest in recent years, particularly its use as a topical antibacterial dressing. Results thus far are extremely encouraging, and demonstrate that honey is effective against a broad range of microorganisms, including multiresistant strains. This in-vitro study complements the work of others and focuses on the impact that a standardized honey can have on multiresistant bacteria that are regularly found in wounds and are responsible for increased morbidity.

  4. Strains of the Harmful Cyanobacterium Microcystis aeruginosa Differ in Gene Expression and Activity of Inorganic Carbon Uptake Systems at Elevated CO2 Levels.

    PubMed

    Sandrini, Giovanni; Jakupovic, Dennis; Matthijs, Hans C P; Huisman, Jef

    2015-11-01

    Cyanobacteria are generally assumed to be effective competitors at low CO2 levels because of their efficient CO2-concentrating mechanism (CCM), and yet how bloom-forming cyanobacteria respond to rising CO2 concentrations is less clear. Here, we investigate changes in CCM gene expression at ambient CO2 (400 ppm) and elevated CO2 (1,100 ppm) in six strains of the harmful cyanobacterium Microcystis. All strains downregulated cmpA encoding the high-affinity bicarbonate uptake system BCT1, whereas both the low- and high-affinity CO2 uptake genes were expressed constitutively. Four strains downregulated the bicarbonate uptake genes bicA and/or sbtA, whereas two strains showed constitutive expression of the bicA-sbtA operon. In one of the latter strains, a transposon insert in bicA caused low bicA and sbtA transcript levels, which made this strain solely dependent on BCT1 for bicarbonate uptake. Activity measurements of the inorganic carbon (Ci) uptake systems confirmed the CCM gene expression results. Interestingly, genes encoding the RuBisCO enzyme, structural carboxysome components, and carbonic anhydrases were not regulated. Hence, Microcystis mainly regulates the initial uptake of inorganic carbon, which might be an effective strategy for a species experiencing strongly fluctuating Ci concentrations. Our results show that CCM gene regulation of Microcystis varies among strains. The observed genetic and phenotypic variation in CCM responses may offer an important template for natural selection, leading to major changes in the genetic composition of harmful cyanobacterial blooms at elevated CO2.

  5. Strains of the Harmful Cyanobacterium Microcystis aeruginosa Differ in Gene Expression and Activity of Inorganic Carbon Uptake Systems at Elevated CO2 Levels

    PubMed Central

    Sandrini, Giovanni; Jakupovic, Dennis; Matthijs, Hans C. P.

    2015-01-01

    Cyanobacteria are generally assumed to be effective competitors at low CO2 levels because of their efficient CO2-concentrating mechanism (CCM), and yet how bloom-forming cyanobacteria respond to rising CO2 concentrations is less clear. Here, we investigate changes in CCM gene expression at ambient CO2 (400 ppm) and elevated CO2 (1,100 ppm) in six strains of the harmful cyanobacterium Microcystis. All strains downregulated cmpA encoding the high-affinity bicarbonate uptake system BCT1, whereas both the low- and high-affinity CO2 uptake genes were expressed constitutively. Four strains downregulated the bicarbonate uptake genes bicA and/or sbtA, whereas two strains showed constitutive expression of the bicA-sbtA operon. In one of the latter strains, a transposon insert in bicA caused low bicA and sbtA transcript levels, which made this strain solely dependent on BCT1 for bicarbonate uptake. Activity measurements of the inorganic carbon (Ci) uptake systems confirmed the CCM gene expression results. Interestingly, genes encoding the RuBisCO enzyme, structural carboxysome components, and carbonic anhydrases were not regulated. Hence, Microcystis mainly regulates the initial uptake of inorganic carbon, which might be an effective strategy for a species experiencing strongly fluctuating Ci concentrations. Our results show that CCM gene regulation of Microcystis varies among strains. The observed genetic and phenotypic variation in CCM responses may offer an important template for natural selection, leading to major changes in the genetic composition of harmful cyanobacterial blooms at elevated CO2. PMID:26319871

  6. [Determination of associated antimicrobial resistance in clinical isolates of Staphylococcus aureus and Pseudomonas aeruginosa in a public hospital in Goiânia, State of Goiás].

    PubMed

    Kobayashi, Cláudia Castelo Branco Artiaga; Sadoyama, Geraldo; Vieira, José Daniel Gonçalves

    2009-01-01

    This study evaluated the associated antimicrobial resistance of Pseudomonas aeruginosa and Staphylococcus aureus in relation to an antimicrobial agent with other drugs. The associated antimicrobial resistance was calculated by means of the relative risk. There was an obvious relationship between oxacillin resistance and resistance to other antimicrobial agents among isolates of oxacillin-resistant Staphylococcus aureus (68.5%), greater than 32%, except for linezolid (6.7%). Pronounced associated resistance among drugs was observed for Pseudomonas aeruginosa isolates, particularly for ciprofloxacin and carbapenems (59.6% to 60.7%) and for aminoglycosides and carbapenems (66.3 % to 67.7 %) and other beta-lactam antibiotics (52.3% to 85.8%). The present study emphasizes the importance of diagnostic cultures and susceptibility testing for selecting the correct antimicrobial agent, with regard to the clinical impact of increased multiresistance and selection of associated antimicrobial resistance.

  7. 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

  8. Molecular epidemiology of Pseudomonas aeruginosa in an intensive care unit.

    PubMed Central

    Döring, G.; Hörz, M.; Ortelt, J.; Grupp, H.; Wolz, C.

    1993-01-01

    Genotyping was used to analyse Pseudomonas aeruginosa isolates from sink drains and 15 intubated patients as part of a 3-month prospective study of strain transmission in a medical-surgical intensive care unit. Ninety percent of all washbasin drains were persistently contaminated with several P. aeruginosa genotypes. In 60% (9/15) of the patients, P. aeruginosa colonization or infection was hospital-acquired: P. aeruginosa strains isolated from these patients were present in hospital sinks or in other patients before their admission. Since all patients were immobile, personnel were the probable route of transmission of P. aeruginosa in the hospital. The mechanism of strain transmission from sinks to hands during hand washing was investigated in a children's hospital. When P. aeruginosa was present at densities of > 10(5)/c.f.u. per ml in sink drains, hand washing resulted in hand contamination with P. aeruginosa via aerosol generation in the majority of experiments or P. aeruginosa was detected using an air sampler above the washing basin. High P. aeruginosa cfu were present at 4.30 h in the eight sinks (5.4 x 10(5)-7.0 x 10(10) c.f.u./ml), whereas at 13.00 h P. aeruginosa c.f.u. were significantly lower (3.1 x 10(2)-8.0 x 10(5) c.f.u./ml). These data reveal that the danger of bacterial contamination of hands during hand washing is highest in the morning. The identified transmission routes demand more effective hygienic measures in hospital settings particularly concerning personnel hands and sink drains. Images Fig. 1 PMID:8519308

  9. Evaluation of genotypic and phenotypic methods to distinguish clinical from environmental Vibrio vulnificus strains.

    PubMed

    Sanjuán, Eva; Fouz, Belén; Oliver, James D; Amaro, Carmen

    2009-03-01

    Vibrio vulnificus is a heterogeneous bacterial species that comprises virulent and avirulent strains from environmental and clinical sources that have been grouped into three biotypes. To validate the typing methods proposed to distinguish clinical from environmental isolates, we performed phenotypic (API 20E, API 20NE, and BIOLOG tests) and genetic (ribotyping and DNA polymorphism at several loci) studies with a large strain collection representing different biotypes, origins, and host ranges. No phenotypic method was useful for biotyping or grouping strains with regard to the origin of an isolate, and only the BIOLOG system was reliable for identifying the strains at the species level. DNA polymorphisms divided the population into three major profiles. Profile 1 strains were vcg type C, 16S rRNA type B, and vvh type 1 and included most of the biotype 1 human septicemic isolates; profile 2 strains were vcg type E, 16S rRNA type A, and vvh type 2 and included all biotype 2 isolates together with biotype 1 isolates from fish and water and some human isolates; and profile 3 strains were vcg type E, 16S rRNA type AB, and vvh type 2 and included biotype 3 strains. Ribotyping divided the species into two groups: one group that included profile 1 biotype 1 isolates and one group that included isolates of all three biotypes with the three profiles described above. In conclusion, no genotyping system was able to distinguish either clinical strains from environmental strains or biogroups within the species V. vulnificus, which suggests that new typing methodologies useful for public health have to be developed for this species.

  10. Pseudomonas aeruginosa essentials: an update on investigation of essential genes.

    PubMed

    Juhas, Mario

    2015-11-01

    Pseudomonas aeruginosa is the leading cause of nosocomial infections, particularly in immunocompromised, cancer, burn and cystic fibrosis patients. Development of novel antimicrobials against P. aeruginosa is therefore of the highest importance. Although the first reports on P. aeruginosa essential genes date back to the early 2000s, a number of more sensitive genomic approaches have been used recently to better define essential genes in this organism. These analyses highlight the evolution of the definition of an 'essential' gene from the traditional to the context-dependent. Essential genes, particularly those indispensable under the clinically relevant conditions, are considered to be promising targets of novel antibiotics against P. aeruginosa. This review provides an update on the investigation of P. aeruginosa essential genes. Special focus is on recently identified P. aeruginosa essential genes and their exploitation for the development of antimicrobials.

  11. Emergence of Metallo-β-Lactamase GIM-1 in a Clinical Isolate of Serratia marcescens

    PubMed Central

    Frontzek, Andre; Pfeifer, Yvonne

    2012-01-01

    The metallo-β-lactamase GIM-1 (German imipenemase) has been found so far only in clinical isolates of Pseudomonas aeruginosa from Germany. Here we report the detection of blaGIM-1 in a clinical strain of Serratia marcescens that was isolated from urine, blood, and wound samples over a period of 20 months. The strain was repeatedly isolated from one patient in two German hospitals and an outpatient department located in the region in which all previously described GIM-1-producing P. aeruginosa strains were identified. PMID:22710114

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

    PubMed Central

    Gupta, Parul; Chhibber, Sanjay; Harjai, Kusum

    2016-01-01

    Background & objectives: Biofilms formed by Pseudomonas aeruginosa lead to persistent infections. Use of antibiotics for the treatment of biofilm induced infection poses a threat towards development of resistance. Therefore, the research is directed towards exploring the property of antibiotics which may alter the virulence of an organism besides altering its growth. The aim of this study was to evaluate the role of subinhibitory concentration of ciprofloxacin (CIP) in inhibiting biofilm formation and virulence of P. aeruginosa. Methods: Antibiofilm potential of subinhibitory concentration of CIP was evaluated in terms of log reduction, biofilm forming capacity and coverslip assay. P. aeruginosa isolates (grown in the presence and absence of sub-MIC of CIP) were also evaluated for inhibition in motility, virulence factor production and quorum sensing (QS) signal production. Results: Sub-minimum inhibitory concentration (sub-MIC) of CIP significantly reduced the motility of P. aeruginosa stand and strain and clinical isolates and affected biofilm forming capacity. Production of protease, elastase, siderophore, alginate, and rhamnolipid was also significantly reduced by CIP. Interpretation & conclusions: Reduction in virulence factors and biofilm formation was due to inhibition of QS mechanism which was indicated by reduced production of QS signal molecules by P. aeruginosa in presence of subinhibitory concentration of CIP. PMID:27488009

  13. Computational discovery of putative quorum sensing inhibitors against LasR and RhlR receptor proteins of Pseudomonas aeruginosa

    NASA Astrophysics Data System (ADS)

    Annapoorani, Angusamy; Umamageswaran, Venugopal; Parameswari, Radhakrishnan; Pandian, Shunmugiah Karutha; Ravi, Arumugam Veera

    2012-09-01

    Drugs have been discovered in the past mainly either by identification of active components from traditional remedies or by unpredicted discovery. A key motivation for the study of structure based virtual screening is the exploitation of such information to design targeted drugs. In this study, structure based virtual screening was used in search for putative quorum sensing inhibitors (QSI) of Pseudomonas aeruginosa. The virtual screening programme Glide version 5.5 was applied to screen 1,920 natural compounds/drugs against LasR and RhlR receptor proteins of P. aeruginosa. Based on the results of in silico docking analysis, five top ranking compounds namely rosmarinic acid, naringin, chlorogenic acid, morin and mangiferin were subjected to in vitro bioassays against laboratory strain PAO1 and two more antibiotic resistant clinical isolates, P. aeruginosa AS1 (GU447237) and P. aeruginosa AS2 (GU447238). Among the five compounds studied, except mangiferin other four compounds showed significant inhibition in the production of protease, elastase and hemolysin. Further, all the five compounds potentially inhibited the biofilm related behaviours. This interaction study provided promising ligands to inhibit the quorum sensing (QS) mediated virulence factors production in P. aeruginosa.

  14. Aloe vera Gel: Effective Therapeutic Agent against Multidrug-Resistant Pseudomonas aeruginosa Isolates Recovered from Burn Wound Infections.

    PubMed

    Goudarzi, Mehdi; Fazeli, Maryam; Azad, Mehdi; Seyedjavadi, Sima Sadat; Mousavi, Reza

    2015-01-01

    Objective. Aloe vera is an herbal medicinal plant with biological activities, such as antimicrobial, anticancer, anti-inflammatory, and antidiabetic ones, and immunomodulatory properties. The purpose of this study was investigation of in vitro antimicrobial activity of A. vera gel against multidrug-resistant (MDR) Pseudomonas aeruginosa isolated from patients with burn wound infections. Methods. During a 6-month study, 140 clinical isolates of P. aeruginosa were collected from patients admitted to the burn wards of a hospital in Tehran, Iran. Antimicrobial susceptibility test was carried out against the pathogens using the A. vera gel and antibiotics (imipenem, gentamicin, and ciprofloxacin). Results. The antibiogram revealed that 47 (33.6%) of all isolates were MDR P. aeruginosa. The extract isolated from A. vera has antibacterial activity against all of isolates. Also, 42 (89.4%) isolates were inhibited by A. vera gel extract at minimum inhibitory concentration (MIC) ≤ 200 µg/mL. MIC value of A. vera gel for other isolates (10.6%) was 800 µg/mL. All of MDR P. aeruginosa strains were inhibited by A. vera at similar MIC50 and MIC90 200 µg/mL. Conclusion. Based on our results, A. vera gel at various concentrations can be used as an effective antibacterial agent in order to prevent wound infection caused by P. aeruginosa.

  15. Invitro Apramycin Activity against multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa.

    PubMed

    Kang, Anthony D; Smith, Kenneth P; Eliopoulos, George M; Berg, Anders H; McCoy, Christopher; Kirby, James E

    2017-03-16

    The in vitro activity of apramycin was compared to that of amikacin, gentamicin, and tobramycin against multidrug-resistant, extensively drug-resistant, and pandrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa. Apramycin demonstrated an MIC50/MIC90 of 8/32μg/ml for A. baumannii and 16/32μg/ml for P. aeruginosa. Only 2% of A. baumannii and P. aeruginosa had an MIC greater than an epidemiological cutoff value of 64μg/ml. In contrast, the MIC50/MIC90 for amikacin, gentamicin, and tobramycin were ≥64/>256μg/ml for A. baumannii with 57%, 95%, and 74% of isolates demonstrating resistance, respectively, and the MIC50/MIC90 were ≥8/256μg/ml for P. aeruginosa with 27%, 50%, and 57% of strains demonstrating resistance, respectively. Apramycin appears to offer promising in vitro activity against highly resistant pathogens. It therefore may warrant further pre-clinical study to assess potential for repurposing as a human therapeutic and relevance as a scaffold for further medicinal chemistry exploration.

  16. Clinical trials with Alice strain, live, attenuated, serum inhibitor-resistant intranasal influenza A vaccine.

    PubMed

    Spencer, M J; Cherry, J D; Powell, K R; Sumaya, C V; Garakian, A J

    1975-10-01

    Two clinical trials with Alice strain intranasal influenza vaccine were performed. In study no. 1 (utilizing random selection and double-blind control), 50 subjects received a bivalent inactivated influenza vaccine intramuscularly, 99 subjects received Alice strain vaccine intranasally, and 50 subjects received a placebo intranasally. No symptomatology could be attributed to the intranasal route of immunization. Convalescent-phase geometric mean titers of hemagglutination inhibition antibody were higher after intramuscular vaccination; seroconversion occurred in 16 or 17 recipients of the Alice strain, with initial titers of less than 1:8. Clinical and virologic surveillance for 20 weeks after vaccination revealed no influenza A illnesses in participants of the study. In study no. 2, 75% of the subjects with initial nasal antibody titers of less than 1:3 developed measurable nasal antibody after receiving Alice strain vaccine.

  17. Draft Genome Sequence of Beneficial Rice Rhizosphere Isolate Pseudomonas aeruginosa PUPa3

    PubMed Central

    Uzelac, Gordana; Bertani, Iris; Kojic, Milan; Paszkiewicz, Konrad H.; Studholme, David J.; Passos da Silva, Daniel

    2014-01-01

    Pseudomonas aeruginosa PUPa3 is a rhizosphere-colonizing and plant growth-promoting strain isolated from the rhizosphere of rice. This strain has, however, been shown to be pathogenic in two nonmammalian infection models. Here we report the draft genome sequence of P. aeruginosa PUPa3. PMID:24994800

  18. Draft Genome Sequence of Beneficial Rice Rhizosphere Isolate Pseudomonas aeruginosa PUPa3.

    PubMed

    Uzelac, Gordana; Bertani, Iris; Kojic, Milan; Paszkiewicz, Konrad H; Studholme, David J; Passos da Silva, Daniel; Venturi, Vittorio

    2014-07-03

    Pseudomonas aeruginosa PUPa3 is a rhizosphere-colonizing and plant growth-promoting strain isolated from the rhizosphere of rice. This strain has, however, been shown to be pathogenic in two nonmammalian infection models. Here we report the draft genome sequence of P. aeruginosa PUPa3.

  19. Twelve aberrant strains of Staphylococcus aureus subsp. aureus from clinical specimens.

    PubMed Central

    Fontana, C; Cellini, L; Dainelli, B

    1993-01-01

    A new biovar of Staphylococcus aureus subsp. aureus was isolated from human clinical specimens and described on the basis of studies of 12 isolates that were compared with 11 standard reference strains. Both DNA hybridization experiments and numerical taxonomy analysis demonstrated that these strains were strictly related to S. aureus subsp. aureus; however, they were significantly different from the latter. The atypical strains belonging to the new biovar can be distinguished from typical S. aureus subsp. aureus strains by their alpha-chymotrypsin, alpha-glucosidase, beta-N-acetylglucosaminidase, lipase (C-14), and leucine arylamidase enzymatic activities and novobiocin resistance. Thus, the combination of alpha-glucosidase and beta-N-acetyl-glucosaminidase is more useful for distinguishing these S. aureus strains from the other, typical ones. PMID:8370737

  20. Comparative Genomics of Environmental and Clinical Stenotrophomonas maltophilia Strains with Different Antibiotic Resistance Profiles

    PubMed Central

    Youenou, Benjamin; Favre-Bonté, Sabine; Bodilis, Josselin; Brothier, Elisabeth; Dubost, Audrey; Muller, Daniel; Nazaret, Sylvie

    2015-01-01

    Stenotrophomonas maltophilia, a ubiquitous Gram-negative γ-proteobacterium, has emerged as an important opportunistic pathogen responsible for nosocomial infections. A major characteristic of clinical isolates is their high intrinsic or acquired antibiotic resistance level. The aim of this study was to decipher the genetic determinism of antibiotic resistance among strains from different origins (i.e., natural environment and clinical origin) showing various antibiotic resistance profiles. To this purpose, we selected three strains isolated from soil collected in France or Burkina Faso that showed contrasting antibiotic resistance profiles. After whole-genome sequencing, the phylogenetic relationships of these 3 strains and 11 strains with available genome sequences were determined. Results showed that a strain’s phylogeny did not match their origin or antibiotic resistance profiles. Numerous antibiotic resistance coding genes and efflux pump operons were revealed by the genome analysis, with 57% of the identified genes not previously described. No major variation in the antibiotic resistance gene content was observed between strains irrespective of their origin and antibiotic resistance profiles. Although environmental strains generally carry as many multidrug resistant (MDR) efflux pumps as clinical strains, the absence of resistance–nodulation–division (RND) pumps (i.e., SmeABC) previously described to be specific to S. maltophilia was revealed in two environmental strains (BurA1 and PierC1). Furthermore the genome analysis of the environmental MDR strain BurA1 showed the absence of SmeABC but the presence of another putative MDR RND efflux pump, named EbyCAB on a genomic island probably acquired through horizontal gene transfer. PMID:26276674

  1. Draft Genome Sequence of the Biofilm-Hyperproducing Acinetobacter baumannii Clinical Strain MAR002

    PubMed Central

    Álvarez-Fraga, Laura; López, María; Merino, María; Rumbo-Feal, Soraya; Tomás, María

    2015-01-01

    We report the draft genome sequence of Acinetobacter baumannii strain MAR002, a biofilm-hyperproducing clinical strain isolated during the study CP/09/0033 (GEIH/REIPI-Ab2010, Spain). The genome of A. baumannii MAR002 has an approximate length of 3,717,929 bp and 3,300 protein-coding sequences, with a C+G content of 39.09%. PMID:26205868

  2. Unexpected Genomic Variability in Clinical and Environmental Strains of the Pathogenic Yeast Candida parapsilosis

    PubMed Central

    Pryszcz, Leszek P.; Németh, Tibor; Gácser, Attila; Gabaldón, Toni

    2013-01-01

    Invasive candidiasis is the most commonly reported invasive fungal infection worldwide. Although Candida albicans remains the main cause, the incidence of emerging Candida species, such as C. parapsilosis is increasing. It has been postulated that C. parapsilosis clinical isolates result from a recent global expansion of a virulent clone. However, the availability of a single genome for this species has so far prevented testing this hypothesis at genomic scales. We present here the sequence of three additional strains from clinical and environmental samples. Our analyses reveal unexpected patterns of genomic variation, shared among distant strains, that argue against the clonal expansion hypothesis. All strains carry independent expansions involving an arsenite transporter homolog, pointing to the existence of directional selection in the environment, and independent origins of the two clinical isolates. Furthermore, we report the first evidence for the existence of recombination in this species. Altogether, our results shed new light onto the dynamics of genome evolution in C. parapsilosis. PMID:24259314

  3. In vitro killing of Escherichia coli, Staphylococcus pseudintermedius and Pseudomonas aeruginosa by enrofloxacin in combination with its active metabolite ciprofloxacin using clinically relevant drug concentrations in the dog and cat.

    PubMed

    Blondeau, J M; Borsos, S; Blondeau, L D; Blondeau, B J

    2012-03-23

    Enrofloxacin is a fluoroquinolone antibacterial agent used to treat infections in companion animals. Enrofloxacin's antimicrobial spectrum includes Gram positive and Gram-negative bacteria and demonstrates concentration-dependent bacteriocidal activity. In dogs and cats, enrofloxacin is partially metabolized to ciprofloxacin and both active agents circulate simultaneously in treated animals at ratios of approximately 60-70% enrofloxacin to 30-40% ciprofloxacin. We were interested in determining the killing of companion animal isolates of Escherichia coli, Staphylococcus pseudintermedius and Pseudomonas aeruginosa by enrofloxacin and ciprofloxacin combined using clinically relevant drug concentrations and ratios. For E. coli isolates exposed to 2.1 and 4.1μg/ml of enrofloxacin/ciprofloxacin at 50:50, 60:40 and 70:30 ratios, a 1.7-2.5log(10) reduction (94-99% kill) was seen following 20min of drug exposure; 0.89-1.7log(10) (92-99% kill) of S. pseudintermedius following 180min of drug exposure; 0.85-3.4log(10) (98-99% kill) of P. aeruginosa following 15min of drug exposure. Killing of S. pseudintermedius was enhanced in the presence of enrofloxacin whereas killing of P. aeruginosa was enhanced in the presence of ciprofloxacin. Antagonism was not seen when enrofloxacin and ciprofloxacin were used in kill assays. The unique feature of partial metabolism of enrofloxacin to ciprofloxacin expands the spectrum of enhanced killing of common companion animal pathogens.

  4. Structural Relationship of the Lipid A Acyl Groups to Activation of Murine Toll-Like Receptor 4 by Lipopolysaccharides from Pathogenic Strains of Burkholderia mallei, Acinetobacter baumannii, and Pseudomonas aeruginosa

    PubMed Central

    Korneev, Kirill V.; Arbatsky, Nikolay P.; Molinaro, Antonio; Palmigiano, Angelo; Shaikhutdinova, Rima Z.; Shneider, Mikhail M.; Pier, Gerald B.; Kondakova, Anna N.; Sviriaeva, Ekaterina N.; Sturiale, Luisa; Garozzo, Domenico; Kruglov, Andrey A.; Nedospasov, Sergei A.; Drutskaya, Marina S.; Knirel, Yuriy A.; Kuprash, Dmitry V.

    2015-01-01

    Toll-like receptor 4 (TLR4) is required for activation of innate immunity upon recognition of lipopolysaccharide (LPS) of Gram-negative bacteria. The ability of TLR4 to respond to a particular LPS species is important since insufficient activation may not prevent bacterial growth while excessive immune reaction may lead to immunopathology associated with sepsis. Here, we investigated the biological activity of LPS from Burkholderia mallei that causes glanders, and from the two well-known opportunistic pathogens Acinetobacter baumannii and Pseudomonas aeruginosa (causative agents of nosocomial infections). For each bacterial strain, R-form LPS preparations were purified by hydrophobic chromatography and the chemical structure of lipid A, an LPS structural component, was elucidated by HR-MALDI-TOF mass spectrometry. The biological activity of LPS samples was evaluated by their ability to induce production of proinflammatory cytokines, such as IL-6 and TNF, by bone marrow-derived macrophages. Our results demonstrate direct correlation between the biological activity of LPS from these pathogenic bacteria and the extent of their lipid A acylation. PMID:26635809

  5. Two Novel Class I Integron Arrays Containing IMP-18 Metallo-β-Lactamase Gene in Pseudomonas aeruginosa Clinical Isolates from Puerto Rico

    PubMed Central

    Martínez, T.; Vazquez, G. J.; Aquino, E. E.; Goering, R. V.

    2012-01-01

    During a β-lactam resistance surveillance study, 12 IMP-18-positive Pseudomonas aeruginosa isolates belonging to 9 different pulsed-field gel electrophoresis groups were identified. In nine isolates, a class I integron with a novel gene array was identified that contained blaIMP-18 and blaOXA-224, while in two isolates the class I integron contained blaIMP-18 and blaOXA-2 but in a new arrangement. Our findings show the dissemination of two novel class I integrons in P. aeruginosa from different regions of Puerto Rico. PMID:22290962

  6. Human Tear Fluid Protects against Pseudomonas aeruginosa Keratitis in a Murine Experimental Model▿

    PubMed Central

    Kwong, Mary S. F.; Evans, David J.; Ni, Minjian; Cowell, Brigitte A.; Fleiszig, Suzanne M. J.

    2007-01-01

    Pseudomonas aeruginosa keratitis is an acute sight-threatening infection. We previously reported that human tear fluid could protect individual human corneal epithelial cells in vitro against invasion by and cytotoxicity due to clinical and laboratory isolates of P. aeruginosa and that the protective mechanism was independent of bacteriostatic activity. In the present study, we examined the effects of human tear fluid in vivo. Tears were collected from healthy human volunteers and were studied in vivo in mice. The effects on the virulence of both invasive and cytotoxic clinical isolates of P. aeruginosa were examined. Tear fluid was found to reduce the severity of disease when corneas were challenged with cytotoxic bacteria immediately after scratch injury, and it completely protected against susceptibility to infection by a cytotoxic strain in a model in which corneas were infected during the healing process 6 h after scratching. Visible protection correlated with the inhibition of bacterial colonization 1, 4, and 48 h postinoculation. Tear fluid also significantly reduced the severity of infections caused by invasive P. aeruginosa in the 6-h-healing model. This result also coincided with significantly reduced bacterial colonization at 48 h. In vitro, human tear fluid significantly reduced the ability of invasive and cytotoxic bacteria to translocate across corneal epithelia and increased transepithelial resistance with or without bacterial inoculation. These data show that human tear fluid can protect against P. aeruginosa corneal infection in vivo and that the mechanism likely involves enhanced epithelial barrier function in addition to protection of individual epithelial cells against bacterial internalization and cytotoxicity. PMID:17325054

  7. [Susceptibility of clinically-isolated bacteria strains to respiratory quinolones and evaluation of antimicrobial agent efficacy by Monte Carlo simulation].

    PubMed

    Kosaka, Tadashi; Yamada, Yukiji; Kimura, Takeshi; Kodama, Mai; Fujitomo, Yumiko; Masaki, Nakanishi; Toshiaki, Komori; Keisuke, Shikata; Fujita, Naohisa

    2016-02-01

    Respiratory quinolones (RQs) are broad-spectrum antimicrobial agents used for the treatment of a wide variety of community-acquired and nosocomial infections. However, bacterial resistance to quinolones has been on the increase. In this study, we investigated the predicted efficacy of RQs for various strains of 9 bacterial species clinically isolated at our university hospital using the Monte Carlo simulation (MCS) method based on pharmacokinetics/pharmacodynamics modeling. In addition, the influence of the patients' renal function on the efficacy of RQs was evaluated. We surveyed antimicrobial susceptibility testing of 9 bacterial species (n = number of strains) [Streptococcus pneumoniae (n = 15), Streptococcus pyogenes (n = 14), Streptococcus agalactiae (n = 19), methicillin-susceptible Staphylococcus aureus (MSSA) (n = 24), Escherichia coli (n = 35), Haemophilus influenzae (n = 17), Klebsiella pneumoniae (n = 14), Pseudomonas aeruginosa (n = 31), and Moraxella catarrhalis (n = 11)] to 4 RQs [garenoxacin (GRNX), levofloxacin (LVFX), sitafloxacin (STFX), and moxifloxacin (MFLX)]. We found that compared with the other RQs, Gram-positive cocci was most resistant to LVFX, and that the minimum inhibitory concentration (MIC₉₀) values for S. pneumoniae, S. pyogenes, S. agalactiae, and MSSA were high (2, 16, > 16, and 8 µg/mL, respectively). In regard to Gram-negative rods, the susceptibility of E. coli to RQs was found to be decreased, with the MIC₉₀ values of GRNX, LVFX, STFX, and MFLX being > 16, 16, 1, and 16 µg/mL, respectively. MCS revealed that the target attainment rate of the area under the unbound concentration-time curve divided by the MIC₉₀ (ƒ · AUC/MIC ratio), against S. pneumoniae was 86.9-100%, but against E. coli was low (52.1-66.2%). The ƒ · AUC/MIC target attainment rate of LVFX against S. pneumoniae, S. pyogenes, and S. agalactiae tended to decrease due to increased creatinine clearance, and that of LVFX and STFX against MSSA also

  8. Immunochemical characterization of polysaccharide antigens from six clinical strains of Enterococci

    PubMed Central

    Hsu, Carolyn T; Ganong, Amanda L; Reinap, Barbara; Mourelatos, Zafiria; Huebner, Johannes; Wang, Julia Y

    2006-01-01

    Background Enterococci have become major nosocomial pathogens due to their intrinsic and acquired resistance to a broad spectrum of antibiotics. Their increasing drug resistance prompts us to search for prominent antigens to develop vaccines against enterococci. Given the success of polysaccharide-based vaccines against various bacterial pathogens, we isolated and characterized the immunochemical properties of polysaccharide antigens from five strains of Enterococcus faecalis and one strain of vancomycin-resistant E. faecium. Results We cultured large batches of each strain, isolated sufficient quantities of polysaccharides, analyzed their chemical structures, and compared their antigenic specificity. Three classes of polysaccharides were isolated from each strain, including a polyglucan, a teichoic acid, and a heteroglycan composed of rhamnose, glucose, galactose, mannosamine, and glucosamine. The polyglucans from all six strains are identical and appear to be dextran. Yields of the teichoic acids were generally low. The most abundant polysaccharides are the heteroglycans. The six heteroglycans are structurally different as evidenced by NMR spectroscopy. They also differ in their antigenic specificities as revealed by competitive ELISA. The heteroglycans are not immunogenic by themselves but conjugation to protein carriers significantly enhanced their ability to induce antibodies. Conclusion The six clinical strains of enterococci express abundant, strain-specific cell-surface heteroglycans. These polysaccharides may provide a molecular basis for serological typing of enterococcal strains and antigens for the development of vaccines against multi-drug resistant enterococci. PMID:16836754

  9. [Recipient capacity of clinical strains of staphylococci belonging to different phage groups].

    PubMed

    Ponomareva, T R; Smolianskaia, A Z

    1976-11-01

    The recipient capacity of the strains of Staph. epidermidis and Staph. areus belonging to different phage groups, as well as the possibility of epidemic distribution of the erythromycin resistance marker among the clinical staphyloccal strains on using the defective phage obtained from strain 8325 P IIde was studied. The defective phage P IIde may be the source of epidemic distribution of the drug resistance among the competent strains of Staph. aureus. All erythromycin sensitive strains of Staph. aureus lysed by the phages of groups I and III proved to be competent recipients of the erythromycin resistance marker. The strains of Staph. aureus of phage group II and phage type 80/81, as well as the strains of Staph. epidermidis were not competent recipients under our experimental conditions. It was not possible to transfer the high level of erythromycin resistance (1000 gamma/ml) on transduction to the strains of phage group I with a relatively low level of resistance to this antibiotic (20-50 gamma/ml.

  10. Genetic diversity of clinical and environmental Vibrio parahaemolyticus strains from the Pacific Northwest.

    PubMed

    Paranjpye, Rohinee; Hamel, Owen S; Stojanovski, Asta; Liermann, Martin

    2012-12-01

    Since 1997, cases of Vibrio parahaemolyticus-related gastroenteritis from the consumption of raw oysters harvested in Washington State have been higher than historical levels. These cases have shown little or no correlation with concentrations of potentially pathogenic V. parahaemolyticus (positive for the thermostable direct hemolysin gene, tdh) in oysters, although significant concentrations of tdh(+) V. parahaemolyticus strains were isolated from shellfish-growing areas in the Pacific Northwest (PNW). We compared clinical and environmental strains isolated from the PNW to those from other geographic regions within the United States and Asia for the presence of virulence-associated genes, including the thermostable direct hemolysin (tdh), the thermostable-related hemolysin (trh), urease (ureR), the pandemic group specific markers orf8 and toxRS, and genes encoding both type 3 secretion systems (T3SS1 and T3SS2). The majority of clinical strains from the PNW were positive for tdh, trh, and ureR genes, while a significant proportion of environmental isolates were tdh(+) but trh negative. Hierarchical clustering grouped the majority of these clinical isolates into a cluster distinct from that including the pandemic strain RIMD2210633, clinical isolates from other geographical regions, and tdh(+), trh-negative environmental isolates from the PNW. We detected T3SS2-related genes (T3SS2β) in environmental strains that were tdh and trh negative. The presence of significant concentrations of tdh(+), trh-negative environmental strains in the PNW that have not been responsible for illness and T3SS2β in tdh- and trh-negative strains emphasizes the diversity in this species and the need to identify additional virulence markers for this bacterium to improve risk assessment tools for the detection of this pathogen.

  11. Mercury(II)-resistance transposons Tn502 and Tn512, from Pseudomonas clinical strains, are structurally different members of the Tn5053 family.

    PubMed

    Petrovski, Steve; Blackmore, Dale W; Jackson, Kerry L; Stanisich, Vilma A

    2011-01-01

    The mercury(II)-resistance transposons Tn502 and Tn512 were sequenced and shown to be members of the Tn5053 family. They are currently the sole representatives from the clinical setting and were obtained from geographically disparate Pseudomonas aeruginosa strains. The family is comprised of six novel transposons that display genetic and structural variability that has arisen in different ways. The mer and tni arms of the transposons can be differently combined, suggesting that chimeric interchanges have occurred, possibly mediated by the TniR resolvase. The mer modules within the mer arms are remnants of Tn21/Tn501-like transposons that inserted into a tni-containing ancestral transposon. The mer modules themselves are polymorphic and that of Tn502 is a new type. It includes the putative urf2M gene, the 3'-end of which expresses a protein and hence is a bone fide gene (tniM). Homologues of tniM occur beyond the Tn5053 family and include Tn21 tnpM. Other studies have implicated tniM and tnpM in transposition. Based on sequence and compositional differences, members of the environmentally widespread Tn5053 family constitute a different lineage from the related and clinically successful intI-containing Tn402 family.

  12. Clinical viability of carotid plaque strain estimation using B-mode ultrasound image sequences.

    PubMed

    Khan, Amir A; Hecker, Joseph C; Lal, Brajesh K; Sikdar, Siddhartha

    2016-08-01

    It is estimated that approximately 30% of ischemic strokes are caused by rupture of plaque in the carotid artery. Development of techniques focusing on identifying plaques that are vulnerable to rupture is thus indispensable for stroke prevention. Recent studies have demonstrated that motion analysis of plaques from B-mode and RF ultrasound (US) image sequences can be used to estimate plaque strain. However, viability of these methods in a clinical setting, with variable acquisition protocols, has not been demonstrated yet. In this paper, we explore the viability of estimating plaque strain from B-mode US images of asymptomatic patients, acquired in a real clinical setting with different acquisition settings, frame rates, and operators. Our proposed strain measures, shear strain rate entropy and variance, combined with the recently reported maximum absolute shear strain rate, show that the plaques fall into two distinct clusters. Moreover, these clusters show good correlations with plaque echolucency and echogenicity. We conclude that B-mode US imaging is a viable tool for characterizing plaque dynamics in clinical environments. In future studies, we plan to implement this method on multi-center studies for longitudinal monitoring of plaque.

  13. Extended Characterization of Corynebacterium pyruviciproducens Based on Clinical Strains from Canada and Switzerland

    PubMed Central

    Hinić, V.; Turan, S.; Schultheiss, E.; Pacheco, A. L.; Frei, R.; Bernard, K.

    2014-01-01

    The species Corynebacterium pyruviciproducens was described in 2010 based on the features of a single strain. In this report, we describe the chemotaxonomic and phenotypic characteristics of 11 C. pyruviciproducens clinical strains isolated in Switzerland and Canada in comparison to the strain 06-17730T. Heterogeneities within the type strain were found in the 16S rRNA gene and in biochemical markers. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) identification of this species could not be achieved since currently this bacterial species is not included in the corresponding database. Reliable identification is obtained only with sequence-based identification tools. Results of antimicrobial susceptibility testing of this species with an extended panel of antimicrobials are presented here for the first time. PMID:24951802

  14. Distribution of AdeABC efflux system genes in genotypically diverse strains of clinical Acinetobacter baumannii.

    PubMed

    Wieczorek, Piotr; Sacha, Paweł; Czaban, Sławomir; Hauschild, Tomasz; Ojdana, Dominika; Kowalczuk, Oksana; Milewski, Robert; Poniatowski, Bogusław; Nikliński, Jacek; Tryniszewska, Elżbieta

    2013-10-01

    Acinetobacter baumannii has emerged as a highly problematic hospital-associated pathogen. Different mechanisms contribute to the formation of multidrug resistance in A. baumannii, including the AdeABC efflux system. Distribution of the structural and regulatory genes encoding the AdeABC efflux system among genetically diverse clinical A. baumannii strains was achieved by using PCR and pulsed-field gel electrophoresis techniques. The distribution of adeABRS genes is extremely high among our A. baumannii strains, except the adeC gene. We have observed a large proportion of strains presenting multidrug-resistance phenotype for several years. The efflux pump could be an important mechanism in these strains in resistance to antibiotics.

  15. Catechin Hydrate Augments the Antibacterial Action of Selected Antibiotics against Staphylococcus aureus Clinical Strains.

    PubMed

    Miklasińska, Maria; Kępa, Małgorzata; Wojtyczka, Robert D; Idzik, Danuta; Dziedzic, Arkadiusz; Wąsik, Tomasz J

    2016-02-20

    Synergistic effects between commonly used antibiotics and natural substances may be an alternative to conventional antibacterial therapies. The objective of the presented study was to assess the in vitro antibacterial activity of catechin hydrate (CH) and evaluate the interactions of CH with selected antibiotics using Staphylococcus aureus clinical and reference strains. CH displayed diverse activity towards examined S. aureus strains, with minimal inhibitory concentrations (MICs) ranging from 256 to 2048 µg/mL. The interaction between CH and antibiotics was assessed by an E-test. The most significant synergistic effects were noticed for CH in combination with clindamycin and erythromycin. For cefoxitin and vancomycin a decrease of MIC values in the presence of CH was also observed, but it did not reach statistical significance. The obtained results demonstrate that CH shows antimicrobial activity against Staphylococcus aureus clinical strains. What is more, we proved a synergistic effect of CH with erythromycin and clindamycin.

  16. Complete genome sequencing and analysis of six enterovirus 71 strains with different clinical phenotypes

    PubMed Central

    2013-01-01

    Background Hand, foot and mouth diseases (HFMD) caused by enterovirus 71(EV71) presents a broad spectrum of clinical manifestations ranging from mild febrile disease to fatal neurolocal disease. However, the mechanism of virulence is unknown. Methods We isolated 6 strains of EV71 from HFMD patients with or without neurological symptoms, and sequenced the whole genomes of the viruses to reveal the virulence factors of EV71. Results Phylogenetic tree based on VP1 region showed that all six strains clustered into C4a of C4 sub-genotype. In the complete polypeptide, 298 positions were found to be variable in all strains, and three of these positions (ValP814/IleP814 in VP1, ValP1148/IleP1148 in 3A and Ala P1728/Cys P1728/Val P1728 in 3C) were conserved among the strains with neurovirulence, but variable in strains without neurovirulence. In the 5′-UTR region, it showed that the first 10 nucleotides were mostly conserved, however from the 11th nucleotide, nucleotide insertions and deletions were quite common. The secondary structure prediction of 5′-UTR sequences showed that two of three strains without neurovirulence (SDLY11 and SDLY48) were almost the same, and all strains with neurovirulence (SDLY96, SDLY107 and SDLY153) were different from each other. SDLY107 (a fatal strain) was found different from other strains on four positions (CP241/TP241, AP571/TP571, CP579/TP579 in 5′-UTR and TP7335/CP7335 in 3′-UTR). Conclusions The three positions (ValP814/IleP814 in VP1, ValP1148/IleP1148 in 3A and Ala P1728/Cys P1728/Val P1728 in 3C), were different between two phenotypes. These suggested that the three positions might be potential virulent positions. And the three varied positions were also found to be conserved in strains with neurovirulence, and variable in strains without neurovirulence. These might reveal that the conservation of two of the three positions or the three together were specific for the strains with neurovirulence. Varation of secondary

  17. Clinical determinants and prognostic significance of the electrocardiographic strain pattern in chronic kidney disease patients.

    PubMed

    Cordeiro, Antonio C; Moraes, Aline A I; Cerutti, Virginia; França, Faustino; Quiroga, Borja; Amodeo, Celso; Picotti, Juliano C; Dutra, Lucas V; Rodrigues, Gabriel D; Amparo, Fernanda C; Lindholm, Bengt; Carrero, Juan Jesús

    2014-05-01

    The electrocardiographic (ECG) strain pattern (Strain) is a marker of left ventricular hypertrophy (LVH) severity that provides additional prognostic information beyond echocardiography (ECHO) in the community level. We sought to evaluate its clinical determinants and prognostic usefulness in chronic kidney disease (CKD) patients. We evaluated 284 non-dialysis-dependent patients with CKD stages 3 to 5 (mean age, 61 years [interquartile range, 53-67 years]; 62% men). Patients were followed for 23 months (range, 13-32 months) for cardiovascular (CV) events and/or death. Strain patients (n = 37; 13%) were using more antihypertensive drugs, had higher prevalence of peripheral vascular disease and smoking, and higher levels of C-reactive protein, cardiac troponin, and brain natriuretic peptide (BNP). The independent predictors of Strain were: left ventricular mass index (LVMI), BNP, and smoking. During follow-up, there were 44 cardiovascular events (fatal and non-fatal) and 22 non-CV deaths; and Strain was associated with a worse prognosis independently of LVMI. Adding Strain to a prognostic model of LVMI improved in 15% the risk discrimination for the composite endpoint and in 12% for the CV events. Strain associates with CV risk factors and adds prognostic information over and above that of ECHO-assessed LVMI. Its routine screening may allow early identification of high risk CKD patients.

  18. Vibrio parahaemolyticus Strains of Pandemic Serotypes Identified from Clinical and Environmental Samples from Jiangsu, China

    PubMed Central

    Li, Jingjiao; Xue, Feng; Yang, Zhenquan; Zhang, Xiaoping; Zeng, Dexin; Chao, Guoxiang; Jiang, Yuan; Li, Baoguang

    2016-01-01

    Vibrio parahaemolyticus has emerged as a major foodborne pathogen in China, Japan, Thailand, and other Asian countries. In this study, 72 strains of V. parahaemolyticus were isolated from clinical and environmental samples between 2006 and 2014 in Jiangsu, China. The serotypes and six virulence genes including thermostable direct hemolysin (TDR) and TDR-related hemolysin (TRH) genes were assessed among the isolates. Twenty five serotypes were identified and O3:K6 was one of the dominant serotypes. The genetic diversity was assessed by multilocus sequence typing (MLST) analysis, and 48 sequence types (STs) were found, suggesting this V. parahaemolyticus group is widely dispersed and undergoing rapid evolution. A total of 25 strains of pandemic serotypes such as O3:K6, O5:K17, and O1:KUT were identified. It is worth noting that the pandemic serotypes were not exclusively identified from clinical samples, rather, nine strains were also isolated from environmental samples; and some of these strains harbored several virulence genes, which may render those strains pathogenicity potential. Therefore, the emergence of these “environmental” pandemic V. parahaemolyticus strains may poses a new threat to the public health in China. Furthermore, six novel serotypes and 34 novel STs were identified among the 72 isolates, indicating that V. parahaemolyticus were widely distributed and fast evolving in the environment in Jiangsu, China. The findings of this study provide new insight into the phylogenic relationship between V. parahaemolyticus strains of pandemic serotypes from clinical and environmental sources and enhance the MLST database; and our proposed possible O- and K- antigen evolving paths of V. parahaemolyticus may help understand how the serotypes of this dispersed bacterial population evolve. PMID:27303379

  19. A murine model of early Pseudomonas aeruginosa lung disease with transition to chronic infection

    PubMed Central

    Bayes, H. K.; Ritchie, N.; Irvine, S.; Evans, T. J.

    2016-01-01

    Pseudomonas aeruginosa (PA) remains an important pathogen in patients with cystic fibrosis (CF) lung disease as well as non-CF bronchiectasis and chronic obstructive airways disease. Initial infections are cleared but chronic infection with mucoid strains ensues in the majority of CF patients and specific interventions to prevent this critical infection transition are lacking. The PA bead model has been widely used to study pulmonary P.aeruginosa infection but has limitations in animal husbandry and in accurately mimicking human disease. We have developed an adapted agar bead murine model using a clinical mucoid strain that demonstrates the key features of transition from transitory to chronic airways infection. Infected animals show very limited acute morbidity and mortality, but undergo infection-related weight loss and neutrophilic inflammation, development of anti-pseudomonal antibodies, variable bacterial clearance, endobronchial infection and microbial adaptation with PA small colony variants. We anticipate this model will allow research into the host and microbial factors governing this critical period in Pseudomonas aeruginosa pulmonary pathogenesis when transition to chronicity is occurring. PMID:27804985

  20. In Vitro Effects of Carbenicillin Combined with Gentamicin or Polymyxin B Against Pseudomonas aeruginosa1

    PubMed Central

    Eickhoff, Theodore C.

    1969-01-01

    Disodium carbenicillin and gentamicin sulfate have both shown promise in the treatment of infections caused by Pseudomonas aeruginosa. This study was designed to explore possible synergistic relationships among the new as well as the established antimicrobial agents used to treat such infections. With an agar dilution technique, minimum inhibitory concentrations of 27 strains of P. aeruginosa were determined in two-dimensional tests. Graphs of equal biological activity (isobolograms) demonstrated moderate synergistic effects of the carbenicillin-gentamicin combination over therapeutically feasible concentration ranges. In contrast, the combination of carbenicillin and polymyxin B showed only additive or slightly antagonistic effects. Tests of bacterial killing confirmed the presence of carbenicillin-gentamicin synergy in 3 of 6 strains of P. aeruginosa, but did not show true antagonism between carbenicillin and polymyxin B. Clinical trials of both drug combinations are advisable to determine whether therapeutic results can be improved, and whether the dosages of gentamicin or polymyxin B can thereby be reduced to lessen their toxic hazards. PMID:4313764

  1. Hypermutable Pseudomonas aeruginosa in Cystic Fibrosis Patients from Two Brazilian Cities

    PubMed Central

    Lutz, Larissa; Leão, Robson Souza; Ferreira, Alex Guerra; Pereira, Dariane Castro; Raupp, Caroline; Pitt, Tyrone; Marques, Elizabeth Andrade

    2013-01-01

    Hypermutable (HPM) strains of Pseudomonas aeruginosa have been found at high frequencies in cystic fibrosis (CF) patients in Europe. We report the results of testing for HPM frequencies, mutator genotype, and antimicrobial resistance of P. aeruginosa strains from Brazilian CF patients. A modified disk diffusion technique was used to quantify antibiotic-resistant subpopulations of an isolate, and estimations of the frequency of mutation to rifampin resistance were determined for 705 isolates from 149 patients attending clinics in two Brazilian cities. Mutations in the mutS gene were detected by sequencing assays. We found 194 (27.5%) HPM isolates in samples from 99 (66.4%) patients. Thirty-five HPM isolates (18.0%) from 31 (31.3%) patients exhibited a high increased spontaneous mutation rate compared with controls, and eight isolates from six patients displayed a defective mutS gene. The dominant HPM population was associated with very low antibiotic resistance levels, while HPM subpopulations were generally more resistant to antimicrobials. A relatively high prevalence of HPM P. aeruginosa in CF patients was associated with surprisingly low antibiotic resistance levels, in contrast to some earlier studies. PMID:23303495

  2. First Complete Providencia rettgeri Genome Sequence, the NDM-1-Producing Clinical Strain RB151

    PubMed Central

    Haggerty, Leanne; Sim, Eby M.; Duarte, Carolina; Castro-Cardozo, Betsy E.; Beltran, Mauricio; Saavedra, Sandra; Vanegas, Natasha; Escobar-Perez, Javier

    2017-01-01

    ABSTRACT Providencia rettgeri is an opportunistic bacterial pathogen of clinical significance due to its association with urinary tract infections and multidrug resistance. Here, we report the first complete genome sequence of P. rettgeri. The genome of strain RB151 consists of a 4.8-Mbp chromosome and a 108-kbp blaNDM-1-positive plasmid. PMID:28104655

  3. Draft Genome Sequences of One Marine and One Clinical Vibrio parahaemolyticus Strain, Both Isolated in Sweden

    PubMed Central

    Pinnell, Lee J.; Tallman, James J.

    2016-01-01

    Vibrio parahaemolyticus is the leading bacterial pathogen associated with seafood consumption. Here, we report the draft genome sequences of one marine and one clinical strain, both isolated in Sweden. These sequences will inform future comparative analysis of V. parahaemolyticus in northern Europe. PMID:27789643

  4. Draft Genome Sequence of a Staphylococcus aureus Strain Isolated from a Cow with Clinical Mastitis

    PubMed Central

    Sharma, Paresh; Reddy, D. Peddi; Kumar, P. Anand; Gadicherla, Ramya; George, Neena

    2015-01-01

    We report here the draft genome of Staphylococcus aureus causing clinical mastitis in a cow from India. It is a major causative agent of mastitis and, further, livestock-associated strains are emerging as a potential threat to public health, thereby warranting studies to understand the genome of this deadly pathogen. PMID:26294628

  5. Effect of Catechins, Green tea Extract and Methylxanthines in Combination with Gentamicin Against Staphylococcus aureus and Pseudomonas aeruginosa

    PubMed Central

    Fazly Bazzaz, Bibi Sedigheh; Sarabandi, Sahar; Khameneh, Bahman; Hosseinzadeh, Hossein

    2016-01-01

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

  6. High Virulence and Antifungal Resistance in Clinical Strains of Candida albicans

    PubMed Central

    Monroy-Pérez, Eric; Paniagua-Contreras, Gloria Luz; Rodríguez-Purata, Pamela; Vaca-Paniagua, Felipe; Vázquez-Villaseñor, Marco; Díaz-Velásquez, Clara; Uribe-García, Alina

    2016-01-01

    Antifungal resistance and virulence properties of Candida albicans are a growing health problem worldwide. To study the expression of virulence and azole resistance genes in 39 clinical strains of C. albicans, we used a model of infection of human vaginal epithelial cells with C. albicans strains isolated from Mexican women with vulvovaginal candidiasis (VVC). The strains were identified by PCR amplification of the ITS1 and ITS2 regions of rRNA. The detection and expression of virulence genes and azole resistance genes MDR1 and CDR1 were performed using PCR and RT-PCR, respectively. All strains were sensitive to nystatin and 38 (97.4%) and 37 (94.9%) were resistant to ketoconazole and fluconazole, respectively. ALS1, SAP4–SAP6, LIP1, LIP2, LIP4, LIP6, LIP7, LIP9, LIP10, and PLB1-PLB2 were present in all strains; SAP1 was identified in 37 (94.8%) isolates, HWP1 in 35 (89.7%), ALS3 in 14 (35.8%), and CDR1 in 26 (66.6%). In nearly all of the strains, ALS1, HWP1, SAP4–SAP6, LIP1–LIP10, PLB1, and PLB2 were expressed, whereas CDR1 was expressed in 20 (51.3%) and ALS3 in 14 (35.8%). In our in vitro model of infection with C. albicans, the clinical strains showed different expression profiles of virulence genes in association with the azole resistance gene CDR1. The results indicate that the strains that infect Mexican patients suffering from VVC are highly virulent and virtually all are insensitive to azoles. PMID:28058052

  7. Design, synthesis, and evaluation of pyrazolo-pyrazole derivatives on Methylisocitratelyase of Pseudomonas aeruginosa: in silico and in vitro study.

    PubMed

    Pulaganti, Madhusudana; C M, Anuradha; Kumar, Chitta Suresh

    2017-02-20

    Pseudomonas aeruginosa is an opportunistic micro-organism causing diseases both in animals and humans. In case of human pathology, the role of P. aeruginosa is one of the major concerns in intensive care septicemia. Presently, the drug resistance strains of P. aeruginosa are arising mainly by developing multiple mechanisms due to its natural and acquired resistance to many of the antimicrobial agents commonly used in clinical practice. As a result, there is a direct need to invent new drugs so that they may restrict the outbreak of multidrug resistant strains. Virtual high-throughput insilico screening, which helps to identify the chemical ligands that bind to the enzymes, is an important tool in drug discovery and the drugs discovered in this way are clinically tested. In this study, Methylisocitratelyase (MICL), which is essential for the survival of the bacterium and which doesn't show any similarity with the humans, was selected to evaluate the functions of high-affinity inhibitors (PPI-analogs) that are identified using the virtual screening approach. By adopting the computational analysis tools, structural, functional, and inhibitor interactions of MICL against P. aeruginosa were identified. The PPIA-32 is found to be the best binding interactions with MICL. PPIA-32 reduces the binding affinity for substrate to residues required for MICL enzyme activity and also Root Mean Square Deviation simulations show the most stable nature of PPA32-MICL(complex) than that of MICL alone, thereby effectively inhibiting the growth of virulent P. aeruginosa. To our surprise, the same phenomenon is also identified with other gram-negative bacteria like Escherichia coli, Klebsiella pneumoniae, and Salmonella typhi.

  8. Antimicrobial resistance profiles of dairy and clinical isolates and type strains of enterococci.

    PubMed

    de Fátima Silva Lopes, Maria; Ribeiro, Tânia; Abrantes, Marta; Figueiredo Marques, José Joaquim; Tenreiro, Rogério; Crespo, Maria Teresa Barreto

    2005-08-25

    The susceptibility to 30 antimicrobial agents was determined by the disk diffusion method for a collection of 172 enterococcal strains, including 96 isolates from dairy sources, 50 isolates of human and veterinary origin, and 26 reference strains from 24 different enterococcal species. Results were analysed by hierarchic numerical methods to cluster strains and to group antimicrobials according to similarity profiles. Resistance to 17 of the 30 antimicrobials showed to be correlated, leading to four groups reflecting the mode of action: quinolones (ofloxacin, enrofloxacin, ciprofloxacin and norfloxacin); macrolides (erythromycin, spiramycin), phenicols (cloramphenicol) and tetracyclins (tetracycline, oxytetracyclin); aminoglycosides (gentamicin, kanamycin) and lincosamides (clindamycin); penicillins (amoxicillin, ampicillin, penicillin G, piperacillin) and carbapenems (imipenem). Overall, the genus Enterococcus behaved as resistant to lincomycin, colistin, polimixin B and, with a few exceptions in dairy isolates, to methicillin. In general, all isolates were susceptible to vancomycin, cloramphenicol and fusidic acid. Clusters containing only dairy isolates were susceptible to the majority of antimicrobials tested, as opposed to clusters constituted only by clinical enterococcal isolates. Among the clinical isolates, 62% were highly multiresistant. Low level gentamicin resistance was found to be associated with clinical enterococci. Among dairy isolates, those that clustered with clinical isolates were both resistant to gentamicin and identified as Enterococcus faecalis. Resistance to macrolides, quinolones, penicillins and imipenem was found to be associated also with clinical environments, mainly with multiresistant isolates, contrary to what is generally agreed as a characteristic of the genus. Veterinary clinical isolates were mainly grouped with the multiresistant clinical human isolates. The 26 reference enterococcal strains were distributed in clusters with

  9. Virulence Gene Profiles of Multidrug-Resistant Pseudomonas aeruginosa Isolated From Iranian Hospital Infections

    PubMed Central

    Fazeli, Nastaran; Momtaz, Hassan

    2014-01-01

    Background: The most common hospital-acquired pathogen is Pseudomonas aeruginosa. It is a multidrug resistant bacterium causing systemic infections. Objectives: The present study was carried out in order to investigate the distribution of virulence factors and antibiotic resistance properties of Pseudomonas aeruginosa isolated from various types of hospital infections in Iran. Patients and Methods: Two-hundred and seventeen human infection specimens were collected from Baqiyatallah and Payambaran hospitals in Tehran, Iran. The clinical samples were cultured immediately and samples positive for P. aeruginosa were analyzed for the presence of antibiotic resistance and bacterial virulence genes using PCR (polymerase chain reaction). Antimicrobial susceptibility testing was performed using disk diffusion methodology with Müeller–Hinton agar. Results: Fifty-eight out of 127 (45.66%) male infection specimens and 44 out of 90 (48.88%) female infection specimens harbored P. aeruginosa. Also, 65% (in male specimens) and 21% (in female specimens) of respiratory system infections were positive for P. aeruginosa, which was a high rate. The genes encoding exoenzyme S (67.64%) and phospholipases C (45.09%) were the most common virulence genes found among the strains. The incidences of various β-lactams encoding genes, including blaTEM, blaSHV, blaOXA, blaCTX-M, blaDHA, and blaVEB were 94.11%, 16.66%, 15.68%, 18.62%, 21.56%, and 17.64%, respectively. The most commonly detected fluoroquinolones encoding gene was gyrA (15. 68%). High resistance levels to penicillin (100%), tetracycline (90.19%), streptomycin (64.70%), and erythromycin (43.13%) were observed too. Conclusions: Our findings should raise awareness about antibiotic resistance in hospitalized patients in Iran. Clinicians should exercise caution in prescribing antibiotics, especially in cases of human infections. PMID:25763199

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

    PubMed Central

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

    2016-01-01

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

  11. Complete Proteome of a Quinolone-Resistant Salmonella Typhimurium Phage Type DT104B Clinical Strain

    PubMed Central

    Correia, Susana; Nunes-Miranda, Júlio D.; Pinto, Luís; Santos, Hugo M.; de Toro, María; Sáenz, Yolanda; Torres, Carmen; Capelo, José Luis; Poeta, Patrícia; Igrejas, Gilberto

    2014-01-01

    Salmonellosis is one of the most common and widely distributed foodborne diseases. The emergence of Salmonella strains that are resistant to a variety of antimicrobials is a serious global public health concern. Salmonella enterica serovar Typhimurium definitive phage type 104 (DT104) is one of these emerging epidemic multidrug resistant strains. Here we collate information from the diverse and comprehensive range of experiments on Salmonella proteomes that have been published. We then present a new study of the proteome of the quinolone-resistant Se20 strain (phage type DT104B), recovered after ciprofloxacin treatment and compared it to the proteome of reference strain SL1344. A total of 186 and 219 protein spots were recovered from Se20 and SL1344 protein extracts, respectively, after two-dimensional gel electrophoresis. The signatures of 94% of the protein spots were successfully identified through matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). Three antimicrobial resistance related proteins, whose genes were previously detected by polymerase chain reaction (PCR), were identified in the clinical strain. The presence of these proteins, dihydropteroate synthase type-2 (sul2 gene), aminoglycoside resistance protein A (strA gene) and aminoglycoside 6'-N-acetyltransferase type Ib-cr4 (aac(6')-Ib-cr4 gene), was confirmed in the DT104B clinical strain. The aac(6')-Ib-cr4 gene is responsible for plasmid-mediated aminoglycoside and quinolone resistance. This is a preliminary analysis of the proteome of these two S. Typhimurium strains and further work is being developed to better understand how antimicrobial resistance is developing in this pathogen. PMID:25196519

  12. Prophage carriage and diversity within clinically relevant strains of Clostridium difficile.

    PubMed

    Shan, Jinyu; Patel, Krusha V; Hickenbotham, Peter T; Nale, Janet Y; Hargreaves, Katherine R; Clokie, Martha R J

    2012-09-01

    Prophages are encoded in most genomes of sequenced Clostridium difficile strains. They are key components of the mobile genetic elements and, as such, are likely to influence the biology of their host strains. The majority of these phages are not amenable to propagation, and therefore the development of a molecular marker is a useful tool with which to establish the extent and diversity of C. difficile prophage carriage within clinical strains. To design markers, several candidate genes were analyzed including structural and holin genes. The holin gene is the only gene present in all sequenced phage genomes, conserved at both terminals, with a variable mid-section. This allowed us to design two sets of degenerate PCR primers specific to C. difficile myoviruses and siphoviruses. Subsequent PCR analysis of 16 clinical C. difficile ribotypes showed that 15 of them are myovirus positive, and 2 of them are also siphovirus positive. Antibiotic induction and transmission electron microscope analysis confirmed the molecular prediction of myoviruses and/or siphovirus presence. Phylogenetic analysis of the holin sequences identified three groups of C. difficile phages, two within the myoviruses and a divergent siphovirus group. The marker also produced tight groups within temperate phages that infect other taxa, including Clostridium perfringens, Clostridium botulinum, and Bacillus spp., which suggests the potential application of the holin gene to study prophage carriage in other bacteria. This study reveals the high incidence of prophage carriage in clinically relevant strains of C. difficile and correlates the molecular data to the morphological observation.

  13. Prophage Carriage and Diversity within Clinically Relevant Strains of Clostridium difficile

    PubMed Central

    Shan, Jinyu; Patel, Krusha V.; Hickenbotham, Peter T.; Nale, Janet Y.; Hargreaves, Katherine R.

    2012-01-01

    Prophages are encoded in most genomes of sequenced Clostridium difficile strains. They are key components of the mobile genetic elements and, as such, are likely to influence the biology of their host strains. The majority of these phages are not amenable to propagation, and therefore the development of a molecular marker is a useful tool with which to establish the extent and diversity of C. difficile prophage carriage within clinical strains. To design markers, several candidate genes were analyzed including structural and holin genes. The holin gene is the only gene present in all sequenced phage genomes, conserved at both terminals, with a variable mid-section. This allowed us to design two sets of degenerate PCR primers specific to C. difficile myoviruses and siphoviruses. Subsequent PCR analysis of 16 clinical C. difficile ribotypes showed that 15 of them are myovirus positive, and 2 of them are also siphovirus positive. Antibiotic induction and transmission electron microscope analysis confirmed the molecular prediction of myoviruses and/or siphovirus presence. Phylogenetic analysis of the holin sequences identified three groups of C. difficile phages, two within the myoviruses and a divergent siphovirus group. The marker also produced tight groups within temperate phages that infect other taxa, including Clostridium perfringens, Clostridium botulinum, and Bacillus spp., which suggests the potential application of the holin gene to study prophage carriage in other bacteria. This study reveals the high incidence of prophage carriage in clinically relevant strains of C. difficile and correlates the molecular data to the morphological observation. PMID:22706062

  14. Clinical isolates and laboratory reference Candida species and strains have varying abilities to form biofilms.

    PubMed

    Alnuaimi, Ali D; O'Brien-Simpson, Neil M; Reynolds, Eric C; McCullough, Michael J

    2013-11-01

    Candida biofilms are a major virulence trait for this yeast. In this study, the biofilm-forming ability of the major medically important clinical and laboratory reference strains was compared. Biofilms were quantified using traditional methods, that is, crystal violet (CV), tetrazolium (XTT) reduction and colony-forming unit assays (CFU), and two new methods: an automated cell counter (ACC) and biofilm suspension turbidity (BST) method. Biofilms could be categorized based on biofilm biomass (high, medium and low) and growth state (high and low). Candida albicans genotypes, A, B and C, showed medium biofilm mass and low growth rate, and only one C. albicans laboratory strain, ATCC MYA-2719, matched this biofilm category. Of all non-albicans Candida species tested, only Candida dubliniensis and Candida glabrata laboratory and clinical isolates had similar biofilm development. The ACC and BST methods for measuring biofilm significantly correlated with CV and CFU biofilm mass measurements. Thus, biofilm mass can be rapidly assessed using biofilm disruptive/cellular nondestructive methods allowing yeast biofilm cells to be used for further analysis. In conclusion, Candida laboratory reference strains and clinical isolates have been shown to form biofilms at different rates; hence for validity, the selection of laboratory reference strains in biofilm studies may be critical for virulence assessment.

  15. Processing plant persistent strains of Listeria monocytogenes appear to have a lower virulence potential than clinical strains in selected virulence models.

    PubMed

    Jensen, Anne; Thomsen, Line E; Jørgensen, Rikke L; Larsen, Marianne H; Roldgaard, Bent B; Christensen, Bjarke B; Vogel, Birte F; Gram, Lone; Ingmer, Hanne

    2008-04-30

    Listeria monocytogenes is an important foodborne bacterial pathogen that can colonize food processing equipment. One group of genetically similar L. monocytogenes strains (RAPD type 9) was recently shown to reside in several independent fish processing plants. Persistent strains are likely to contaminate food products, and it is important to determine their virulence potential to evaluate risk to consumers. We compared the behaviour of food processing persistent and clinical L. monocytogenes strains in four virulence models: Adhesion, invasion and intracellular growth was studied in an epithelial cell line, Caco-2; time to death in a nematode model, Caenorhabditis elegans and in a fruit fly model, Drosophila melanogaster and fecal shedding in a guinea pig model. All strains adhered to and grew in Caco-2 cells in similar levels. When exposed to 10(6) CFU/ml, two strains representing the persistent RAPD type 9 invaded Caco-2 cells in lower numbers (10(2)-10(3) CFU/ml) as compared to the four other strains (10(4)-10(6) CFU/ml), including food and human clinical strains. In the D. melanogaster model, the two RAPD type 9 strains were among the slowest to kill. Similarly, the time to reach 50% killed C. elegans worms was longer (110 h) for the RAPD type 9 strains than for the other four strains (80 h). The Scott A strain and one RAPD type 9 strain were suspended in whipping cream before being fed to guinea pigs and the persistent RAPD type 9 strain was isolated from feces in a lower level (approximately 10(2) CFU/g) than the Scott A strain (approximately 10(5) CFU/g) (P<0.05). The addition of NaCl has been shown to cause autoaggregation and increases adhesion of L. monocytogenes to plastic. However, growth in the presence of NaCl did not alter the behaviour of the tested L. monocytogenes strains in the virulence models. Overall, the two strains representing a very common fish processing plant persistent group (RAPD type 9) appear to have a lower virulence potential in

  16. [Characteristics of selected virulence factors of Enterobacter cloacae strains isolated from clinical specimens].

    PubMed

    Nieradko, Józef; Kurlenda, Juliana

    2004-01-01

    We demonstrated that Enterobacter cloacae possesses a selective haemolytic activity on sheep erythrocytes. All the screened strains showed a haemolytic activity on sheep erythrocytes when cultures were preincubated with beta-mercaptoethanol. The investigation circulation of the genes encoding extended spectrum beta-lactamases (ESBL) shows that beta-lactamase producers can be ascribed to specific patterns of plasmids. We also demonstrated that genetic material from E. coli can be transferred and established in selected Enterobacter cloacae strains. In a survival tests we demonstrated that similarly to Salmonella or Vibrio clinical isolates Enterobacter cloacae doesn't demonstrate acid tolerance.

  17. Enterococcus faecalis as multidrug resistance strains in clinical isolates in Imam Reza Hospital in Kermanshah, Iran.

    PubMed

    Mohammadi, F; Ghafourian, S; Mohebi, R; Taherikalani, M; Pakzad, I; Valadbeigi, H; Hatami, V; Sadeghifard, N

    2015-01-01

    The current study aimed to investigate the prevalence of vancomycin-resistant Enterococcus in E. faecalis and E. faecium and antimicrobial susceptibility patterns, then dominant genes responsible for vancomycin resistance were determined. For this propose, 180 clinical isolates of Enterococcus were subjected for identification and antibiotic susceptibility assay. Then, the gene responsible vancomycin resistant strains were determined. The results demonstrated the E. faecalis as a dominant Enterococcus. Resistance to erythromycin was dominant and multidrug resistance strains observed in E. faecalis. vanA was responsible for vancomycin resistance. In conclusion, a high rate of resistance to antibiotics in Enterococcus is clearly problematic, and a novel strategy is needed to decrease resistance in Enterococcus.

  18. Bacteriophage-based therapy in cystic fibrosis-associated Pseudomonas aeruginosa infections: rationale and current status.

    PubMed

    Hraiech, Sami; Brégeon, Fabienne; Rolain, Jean-Marc

    2015-01-01

    Pulmonary infections involving Pseudomonas aeruginosa are among the leading causes of the deterioration of the respiratory status of cystic fibrosis (CF) patients. The emergence of multidrug-resistant strains in such populations, favored by iterative antibiotic cures, has led to the urgent need for new therapies. Among them, bacteriophage-based therapies deserve a focus. One century of empiric use in the ex-USSR countries suggests that bacteriophages may have beneficial effects against a large range of bacterial infections. Interest in bacteriophages has recently renewed in Western countries, and the in vitro data available suggest that bacteriophage-based therapy may be of significant interest for the treatment of pulmonary infections in CF patients. Although the clinical data concerning this specific population are relatively scarce, the beginning of the first large randomized study evaluating bacteriophage-based therapy in burn infections suggests that the time has come to assess the effectiveness of this new therapy in CF P. aeruginosa pneumonia. Consequently, the aim of this review is, after a brief history, to summarize the evidence concerning bacteriophage efficacy against P. aeruginosa and, more specifically, the in vitro studies, animal models, and clinical trials targeting CF.

  19. Biological activities of pyochelins: iron-chelating agents of Pseudomonas aeruginosa.

    PubMed Central

    Liu, P V; Shokrani, F

    1978-01-01

    Strains of Pseudomonas aeruginosa able to grow readily in serum (serum resistant) produce siderophores in large quantity, enabling them to extract iron from transferrins. The term pyochelin has been proposed for this group of compounds. Pyochelin extractable with ethyl acetate and designated pyochelin A appears to be a mixture of catechols and other phenolates. The structures of water-soluble siderophores, designated pyochelin B, have not been determined. Pyochelins enabled growth in serum of strains of serum-sensitive P. aeruginosa and other gram-negative bacilli. Serum-resistant strains of P. aeruginosa tended to be more virulent than equally toxigenic strains of the serum-sensitive group. However, incorporation of pyochelins into the inocula of serum-sensitive strains could reduce, rather than enhance, their virulence. Utilization of pyochelins by serum-sensitive strains of P. aeruginosa rendered some of these organisms resistant to pyocins which were otherwise lethal to them. Images PMID:103839

  20. Comparison of different methods for determining beta-lactam susceptibility in Pseudomonas aeruginosa.

    PubMed

    Sapino, Barbara; Mazzuccato, Sandra; Solinas, Maria; Gion, Massimo; Grandesso, Stefano

    2012-10-01

    This study compared the results of antimicrobial susceptibility testing of 77 clinical strains isolated for Pseudomonas aeruginosa to five beta-lactam agents: aztreonam, ceftazidime, imipenem, meropenem and piperacillin+tazobactam. Four different methods were employed: two automated systems (VITEK 2 and Sensititre) and two standardized manual methods (Kirby-Bauer and E-test). The concordances for the susceptibility categories were better for Kirby-Bauer (medium value =89.6%), followed by Sensititre (medium value =87.0%) and VITEK 2 (medium value =82.8%). The disk diffusion method did not present very major errors in comparison to the two automated systems.

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

    PubMed

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

    2016-08-11

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

  2. Clinical outcomes of osteomyelitis patients infected with methicillin-resistant Staphylococcus aureus USA-300 strains.

    PubMed

    Peyrani, P; Allen, M; Seligson, D; Roberts, C; Chen, A; Haque, N; Zervos, M; Wiemken, T; Harting, J; Christensen, D; Ramirez, R

    2012-03-01

    Methicillin-resistant Staphylococcus aureus (MRSA) USA-300 strains have emerged as an important cause of community-acquired infections. These strains have been recognized as an etiology of osteomyelitis but data on their incidence and outcomes are limited. We retrospectively studied the incidence and clinical outcomes of MRSA USA-300 osteomyelitis in patients at the University of Louisville Hospital and the Henry Ford Health System between January 2007 and March 2008. Pulsed-field gel electrophoresis was used to determine USA type. Clinical outcomes were defined as management success versus failure at 12 months. Chi-square tests, Fisher exact tests, and Mann-Whitney tests were used to compare patient characteristics on the basis of clinical outcomes and USA type. Of the 50 patients with MRSA osteomyelitis, 27 (54%) had the USA-300 strain. Clinical failure was identified in 22% (6/27) of the patients with MRSA USA-300 and in 30% (7/23) of the patients with MRSA non-USA-300 osteomyelitis (P = .509). Our results showed that MRSA USA-300 is a significant etiology of MRSA osteomyelitis. With current surgical and medical management, outcomes of patients with MRSA USA-300 osteomyelitis are similar to those of patients with MRSA non-USA-300 osteomyelitis.

  3. Screening of antibiotics resistance to Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii by an advanced expert system.

    PubMed

    Nakamura, Tatsuya; Takahashi, Hakuo

    2005-12-01

    The VITEK2 advanced expert system (AES) gives information about the antibiotics-resistance mechanisms based on the biological validation derived from the VITEK2 susceptibility result. In this study, we investigated whether or not this system correctly categorized the beta-lactamase resistance mechanism data derived from the VITEK2 susceptibility result using the testing card, AST-N025, with Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii. We used 131 strains, and their phenotypes were determined according to the biological and genetic screening. The AES analysis result matched the phenotype testing in 120 (91.6%) of the 131 strains. Incorrect findings were found in six strains, including three strains of Serratia marcescens. The resistance mechanism could not be determined in five strains, including three strains of Providencia rettgeri. The analysis of those phenotypes agreed in 34 (97.1%) among 35 strains with extended spectrum beta-lactamase (ESBL), and in 27 (96.4%) among 28 strains with high-level cephalosporinase. The agreement ratio in the phenotype was very high as we expected. The incorrect and nondeterminable samples were strains with relatively high cephalosporinase that has variation of outer membrane protein. The AES was able to detect the phenotype for carbapenemase. The AES is a clinically useful system that allows taking prompt measures to treat patients because it can provide information about the resistance mechanism in less than half a day after starting the analysis.

  4. Clinical Correlates and Predictors of Caregiver Strain in Children with Chronic Tic Disorders

    PubMed Central

    Ramanujam, Krishnapriya; Himle, Michael B.; Hayes, Loran P.; Woods, Douglas W.; Scahill, Lawrence; Sukhodolsky, Denis G.; Wilhelm, Sabine; Deckersbach, Thilo; Peterson, Alan L.; Specht, Matt; Walkup, John T.; Chang, Susanna; Piacentini, John

    2015-01-01

    Although tics are the defining feature of chronic tic disorders (CTD), many children experience comorbid internalizing and externalizing problems that contribute to impairment across several domains, including family functioning. The current study examined clinical correlates and predictors of caregiver strain in parents of children with CTD. Participants were 123 children and adolescents diagnosed with a CTD who participated in a randomized-controlled trial of behavior therapy for reducing tics. Results showed that a combination of disruptive behavior, inattention/hyperactivity, and tic intensity best explained objective strain and a combination of inattention/hyperactivity and tic intensity were the best predictors of subjective caregiver strain. Implications of these findings for care providers are discussed. PMID:26855465

  5. [Antimicrobial resistance and molecular epidemiology of Staphylococcus pseudintermedius strains isolated from dog clinical samples].

    PubMed

    Vigo, Germán B; Giacoboni, Gabriela I; Gagetti, Paula S; Pasterán, Fernando G; Corso, Alejandra C

    2015-01-01

    Twenty-eight strains isolated from dog clinical samples identified as Staphylococcus pseudintermedius by mass spectrometry (MALDI-TOF) were studied to assess antimicrobial susceptibility by the diffusion method and clonal relationship by pulsed field gel electrophoresis (PFGE). Methicillin resistance (3/28 isolates; 10,7%) was evaluated by mecA PCR. Fifteen strains (53.6%) were resistant to at least one of the antibiotics tested, and eleven of them (39.3%) showed multiple resistance (3 or more antimicrobial families). Eleven isolates (39.3%) were resistant to erythromycin due to the presence of ribosomal methylase ermB, whereas clindamycin inducible resistance was not detected. Twenty-seven (27) clonal types were differentiated by PFGE, suggesting high clonal diversity. We emphasize that the finding of multiresistant S. psedintermedius strains is an emerging problem to be considered in veterinary diagnostic laboratory treatment of canine infections and in public health settings.

  6. D‐amino acids do not inhibit Pseudomonas aeruginosa biofilm formation

    PubMed Central

    Frye, Mitchell; Gagnon, Patricia; Vogel, Joseph P.; Chole, Richard

    2016-01-01

    Objective Pseudomonas aeruginosa, a known biofilm‐forming organism, is an opportunistic pathogen that plays an important role in chronic otitis media, tracheitis, cholesteatoma, chronic wounds, and implant infections. Eradication of biofilm infections has been a challenge because the biofilm phenotype provides bacteria with a protective environment from the immune system and antibiotics; thus, there has been great interest in adjunctive molecules that may inhibit biofilm formation or cause biofilm dispersal. There are reports that D‐amino acids may inhibit biofilms. In this study, we test the ability of various D‐amino acids to inhibit P. aeruginosa biofilm formation in vitro. Study Design We evaluated the effect of D‐alanine (10 mM), D‐leucine (10 mM), D‐methionine (10 mM), D‐tryptophan (10 mM), and D‐tyrosine (10 uM and 1 mM) on biofilm formation in two commonly studied laboratory strains of P. aeruginosa: PAO1 and PA14. Methods Biofilms were grown in 24‐well and 96‐well tissue culture plates, documented photographically and stained with 0.1% crystal violet and solubilized in 33% glacial acetic acid for quantification. Results In strains PAO1 and PA14, the addition of D‐amino acids did not result in an inhibitory effect on biofilm growth in 24‐well plates. Repeating the study in 96‐well plates confirmed our findings that D‐amino acids do not inhibit biofilm formation of P. aeruginosa. Conclusion We conclude that D‐amino acids only slow the production of biofilms rather than completely prevent biofilm formation; therefore, D‐amino acids represent a poor option for potential clinically therapeutic interventions. Level of Evidence N/A. PMID:28286870

  7. Evaluation of efflux pumps gene expression in resistant Pseudomonas aeruginosa isolates in an Iranian referral hospital

    PubMed Central

    Pourakbari, Babak; Yaslianifard, Sahar; Yaslianifard, Somaye; Mahmoudi, Shima; Keshavarz-Valian, Sepideh; Mamishi, Setareh

    2016-01-01

    Background and Objectives: Pseudomonas aeruginosa (PA) is one of the most important causes of nosocomial infections and has an intrinsic resistance to many antibiotics. Among all the resistance-nodulation-division (RND) pumps of P. aeruginosa, MexAB-OprM is the first efflux pump found to target multiple classes of antibiotics. This study was aimed to evaluate the expression level of genes expressing MexAB-OprM in clinical isolates of P. aeruginosa. Materials and Methods: In this study, 45 P. aeruginosa strains were isolated from patients admitted to Children’s Medical Center Hospital, an Iranian referral hospital. Disk diffusion and Minimum Inhibitory Concentration (MIC) methods were used for determination of the patterns of resistance to antibiotics. Real-time PCR was used to investigate the expression level of genes of MexAB-OprM efflux pump. Results: Among 45 resistant PA isolates, the frequency of genes overexpression was as follows: MexA (n=25, 55.5%), MexB (n=24, 53.3%) and OprM (n=16, 35.5%). In addition, in 28 strains (62%) overexpression was observed in one of the studied three genes of MexAB-OprM efflux pump. Conclusion: In our study 28 isolates (62%) had increased expression level of efflux pumps genes, MexAB-OprM. Although the efflux pumps play important roles in increasing the resistance towards different antibiotics but the role of other agents and mechanisms in evolution of resistance should not be ignored. Since the concomitant overproduction of other Mex efflux systems might have additive effects on antibiotic resistance, the co-expressing of a multicomponent efflux pump is recommended. On the other hand, the concomitant overproduction of two Mex pumps might have additive effects on resistance to antibiotic. Therefore co-expressing of Mex efflux systems is recommended. PMID:28210464

  8. [Morphologic, cultural, and biochemical properties of cultures of Pseudomonas aeruginosa isolated from patients, animals, and the environment].

    PubMed

    Litovchenko, P P; Zabotina, I V

    1981-05-01

    The properties of 279 Ps. aeruginosa strains were studied in 70 tests. The use of a synthetic peptone-free mineral medium for the determination of sugar oxidation was shown to have advantages over the use of liquid Giess' media. Ps. aeruginosa cultures isolated from human patients, animals, soil and water were characterized by a number of common signs, irrespective of their origin. The strains isolated from human patients were resistant practically to all antibiotics widely used in clinical practice; the cultures isolated from soil and water retained their sensitivity to antibiotics; the strains isolated from animals retained sensitivity to some antibiotics. To identify Ps. aeruginosa in practical bacteriological laboratories, the following parameters should be determined: mobility; the character of growth in Levine's and Ploskirev's media; ability to grow at 42 degrees C and 4 degrees C; the fermentation of carbohydrates in Olkenitsky's medium and their oxidation in a mineral medium; indole and hydroxide sulfide production; the methyl red and Voges--Proskauer reaction; the presence of pigments, oxidase, catalase, gelatinase, nitrate reductase and arginine dehydrolase, urease; resistance to antibiotics.

  9. 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

  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. The bactericidal effect on Pseudomonas strains of adriamycin associated with quinolones.

    PubMed

    Castelli, M; Baggio, G; Aresca, P; Bossa, R; Galatulas, I

    1989-01-01

    The in vitro antibacterial activity of quinolone compounds was assessed on strains of Pseudomonas aeruginosa isolated from clinical infections. The bactericidal effect of quinolones was high and their respective antibacterial properties with adriamycin remained unimpaired on strains both sensitive and resistant to betalactam and aminoglycoside antibiotics. The cytotoxic effect of the combination of adriamycin and quinolones was determined in cultured P388 leukemia cells: no interference with the cytotoxic activity of adriamycin was observed.

  12. 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.

  13. In vivo challenging of polymyxins and levofloxacin eye drop against multidrug-resistant Pseudomonas aeruginosa keratitis.

    PubMed

    Tajima, Kazuki; Miyake, Taku; Koike, Naohito; Hattori, Takaaki; Kumakura, Shigeto; Yamaguchi, Tetsuo; Matsumoto, Tetsuya; Fujita, Koji; Kuroda, Masahiko; Ito, Norihiko; Goto, Hiroshi

    2014-06-01

    The purposes of this study were to establish a rabbit multidrug-resistant Pseudomonas aeruginosa (MDRP) keratitis model, and test the efficacy of levofloxacin, colistin methanesulfate (CL-M), colistin sulfate (CL-S) and polymyxin B (PL-B) against MDRP infection. In a rabbit eye, making a 2-mm circular corneal excision, and MDRP strain #601 or representative P. aeruginosa strain IID1210 were instilled into the corneal concavity. IID1210 was used to confirm this model developed P. aeruginosa keratitis. After MDRP keratitis developed, we treated the eyes with levofloxacin, CL-M, CL-S or PL-B eye drops. The infected eyes were evaluated by clinical score, histopathological examination and viable bacterial count (CFU). Rabbits developed MDRP keratitis reproducibly after instilled the bacteria into the corneal lesion. MDRP produced severe keratitis similarly with IID1210, as shown by slit lamp examination and clinical score. In MDRP keratitis models, clinical scores and viable bacterial counts were significantly lower in levofloxacin- and CL-M-treated groups compared with PBS-treated group, but the magnitudes of reduction were not remarkable. However, clinical scores were dramatically lowered in CL-S- and PL-B-treated groups compared with PBS-treated group. CL-S- and PL-B-treated group were kept corneal translucency and little influx of polymorphonuclear neutrophils in histopathological examination. In addition, both CL-S- and PL-B-treated groups were not detected viable bacteria in infected cornea. Using our MDRP keratitis model, we showed that topical levofloxacin and CL-M are not adequately effective, while CL-S and PL-B are efficacious in controlling MDRP keratitis. Especially, PL-B, which is commercially available eye drop, might be most effective against MDRP.

  14. Dynorphin Activates Quorum Sensing Quinolone Signaling in Pseudomonas aeruginosa

    PubMed Central

    Zaborina, Olga; Lepine, Francois; Xiao, Gaoping; Valuckaite, Vesta; Chen, Yimei; Li, Terry; Ciancio, Mae; Zaborin, Alex; Petroff, Elaine; Turner, Jerrold R; Rahme, Laurence G; Chang, Eugene; Alverdy, John C

    2007-01-01

    There is now substantial evidence that compounds released during host stress directly activate the virulence of certain opportunistic pathogens. Here, we considered that endogenous opioids might function as such compounds, given that they are among the first signals to be released at multiple tissue sites during host stress. We tested the ability of various opioid compounds to enhance the virulence of Pseudomonas aeruginosa using pyocyanin production as a biological readout, and demonstrated enhanced virulence when P. aeruginosa was exposed to synthetic (U-50,488) and endogenous (dynorphin) κ-agonists. Using various mutants and reporter strains of P. aeruginosa, we identified involvement of key elements of the quorum sensing circuitry such as the global transcriptional regulator MvfR and the quorum sensing-related quinolone signaling molecules PQS, HHQ, and HQNO that respond to κ-opioids. The in vivo significance of κ-opioid signaling of P. aeruginosa was demonstrated in mice by showing that dynorphin is released from the intestinal mucosa following ischemia/reperfusion injury, activates quinolone signaling in P. aeruginosa, and enhances the virulence of P. aeruginosa against Lactobacillus spp. and Caenorhabditis elegans. Taken together, these data demonstrate that P. aeruginosa can intercept opioid compounds released during host stress and integrate them into core elements of quorum sensing circuitry leading to enhanced virulence. PMID:17367209

  15. Rapid microarray-based genotyping of Chlamydia spp. strains from clinical tissue samples.

    PubMed

    Sachse, Konrad; Ruettger, Anke

    2015-01-01

    Pathogenic Chlamydia (C.) psittaci and C. trachomatis strains can be genotyped based on variations in the ompA genomic locus. In the present chapter, we describe rapid genotyping assays for both chlamydial agents using the ArrayStrip™ (AS) microarray platform. The test is targeting multiple discriminatory sites in the variable domains of the ompA gene by using 35 (C. psittaci) and 61 (C. trachomatis) oligonucleotide probes representing genotype-specific polymorphisms. In addition to discrimination among the established genotypes, this approach allows identification of atypical strains that were not accessible to typing using previously established techniques, such as PCR-RFLP or serotyping. The present DNA microarray assay can be conducted directly on clinical tissue samples and is suitable for tracing epidemiological chains and exploring the dissemination of particular genotypes. The procedure is easy to handle and economically affordable, and it allows genotyping of up to 32 clinical samples per day, thus lending itself for routine diagnosis as well.

  16. Prevalence of Multidrug-resistant, Extensively Drug-resistant, and Pandrug-resistant Pseudomonas aeruginosa from a Tertiary Level Intensive Care Unit

    PubMed Central

    Gill, JS; Arora, Sunil; Khanna, SP; Kumar, KVS Hari

    2016-01-01

    Background: Infection by Pseudomonas aeruginosa is common in the Intensive Care Unit (ICU), leading to increased morbidity and mortality. The organism is classified into various phenotypes based on the drug resistance pattern, namely, drug-resistant (DR), multi-DR (MDR), extensively DR (XDR), and pan-DR (PDR). We aim to study the incidence of P. aeruginosa phenotypes in a tertiary level ICU. Materials and Methods: We conducted this prospective, observational study for 2 years (January 2014-December 2015) and collected appropriate clinical samples (blood, urine, wound discharge, etc.,) from all the patients admitted to ICU. We excluded patients with known septicemia and P. aeruginosa infection. Group 1 comprised a total 1915 patient samples and Group 2 comprised 100 active surveillance samples, collected from the medical staff and the hospital environment. The data were analyzed using appropriate statistical methods, and a P < 0.05 was considered statistically significant. Results: We isolated 597 pathogenic bacteria out of 1915 specimens, giving a culture positivity rate of 31.2%. Klebsiella (43%), Acinetobacter (22%), and P. aeruginosa (15%) were the top three isolated bacteria. None of the surveillance samples grew P. aeruginosa. Antibiotic resistance studies revealed that 47.7% of P. aeruginosa isolates were DR, 50% were MDR, and 2.3% were XDR phenotype. None of the strains showed PDR phenotype. Conclusion: Our data revealed a high prevalence of DR phenotypes of P. aeruginosa in the ICU. Judicious use of antibiotics and strict infection control measures are essential to reduce the prevalence of drug resistance. PMID:27942195

  17. Similar frequencies of Pseudomonas aeruginosa isolates producing KPC and VIM carbapenemases in diverse genetic clones at tertiary-care hospitals in Medellín, Colombia.

    PubMed

    Vanegas, Johanna M; Cienfuegos, Astrid V; Ocampo, Ana M; López, Lucelly; del Corral, Helena; Roncancio, Gustavo; Sierra, Patricia; Echeverri-Toro, Lina; Ospina, Sigifredo; Maldonado, Natalia; Robledo, Carlos; Restrepo, Andrea; Jiménez, J Natalia

    2014-11-01

    Carbapenem-resistant Pseudomonas aeruginosa has become a serious health threat worldwide due to the limited options available for its treatment. Understanding its epidemiology contributes to the control of antibiotic resistance. The aim of this study was to describe the clinical and molecular characteristics of infections caused by carbapenem-resistant P. aeruginosa isolates in five tertiary-care hospitals in Medellín, Colombia. A cross-sectional study was conducted in five tertiary-care hospitals from June 2012 to March 2014. All hospitalized patients infected by carbapenem-resistant P. aeruginosa were included. Clinical information was obtained from medical records. Molecular analyses included PCR for detection of bla(VIM), bla(IMP), bla(NDM), bla(OXA-48), and bla(KPC) genes plus pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) for molecular typing. A total of 235 patients were enrolled: 91.1% of them were adults (n = 214), 88.1% (n = 207) had prior antibiotic use, and 14.9% (n = 35) had urinary tract infections. The bla(VIM-2) and bla(KPC-2) genes were detected in 13.6% (n = 32) and 11.5% (n = 27), respectively, of all isolates. Two isolates harbored both genes simultaneously. For KPC-producing isolates, PFGE revealed closely related strains within each hospital, and sequence types (STs) ST362 and ST235 and two new STs were found by MLST. With PFGE, VIM-producing isolates appeared highly diverse, and MLST revealed ST111 in four hospitals and five new STs. These results show that KPC-producing P. aeruginosa is currently disseminating rapidly and occurring at a frequency similar to that of VIM-producing P. aeruginosa isolates (approximately 1:1 ratio) in Medellín, Colombia. Diverse genetic backgrounds among resistant strains suggest an excessive antibiotic pressure resulting in the selection of resistant strains.

  18. Similar Frequencies of Pseudomonas aeruginosa Isolates Producing KPC and VIM Carbapenemases in Diverse Genetic Clones at Tertiary-Care Hospitals in Medellín, Colombia

    PubMed Central

    Vanegas, Johanna M.; Cienfuegos, Astrid V.; Ocampo, Ana M.; López, Lucelly; del Corral, Helena; Roncancio, Gustavo; Sierra, Patricia; Echeverri-Toro, Lina; Ospina, Sigifredo; Maldonado, Natalia; Robledo, Carlos; Restrepo, Andrea

    2014-01-01

    Carbapenem-resistant Pseudomonas aeruginosa has become a serious health threat worldwide due to the limited options available for its treatment. Understanding its epidemiology contributes to the control of antibiotic resistance. The aim of this study was to describe the clinical and molecular characteristics of infections caused by carbapenem-resistant P. aeruginosa isolates in five tertiary-care hospitals in Medellín, Colombia. A cross-sectional study was conducted in five tertiary-care hospitals from June 2012 to March 2014. All hospitalized patients infected by carbapenem-resistant P. aeruginosa were included. Clinical information was obtained from medical records. Molecular analyses included PCR for detection of blaVIM, blaIMP, blaNDM, blaOXA-48, and blaKPC genes plus pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) for molecular typing. A total of 235 patients were enrolled: 91.1% of them were adults (n = 214), 88.1% (n = 207) had prior antibiotic use, and 14.9% (n = 35) had urinary tract infections. The blaVIM-2 and blaKPC-2 genes were detected in 13.6% (n = 32) and 11.5% (n = 27), respectively, of all isolates. Two isolates harbored both genes simultaneously. For KPC-producing isolates, PFGE revealed closely related strains within each hospital, and sequence types (STs) ST362 and ST235 and two new STs were found by MLST. With PFGE, VIM-producing isolates appeared highly diverse, and MLST revealed ST111 in four hospitals and five new STs. These results show that KPC-producing P. aeruginosa is currently disseminating rapidly and occurring at a frequency similar to that of VIM-producing P. aeruginosa isolates (approximately 1:1 ratio) in Medellín, Colombia. Diverse genetic backgrounds among resistant strains suggest an excessive antibiotic pressure resulting in the selection of resistant strains. PMID:25210071

  19. Rapid and simple determination of ciprofloxacin resistance in clinical strains of Escherichia coli.

    PubMed

    Santiso, Rebeca; Tamayo, María; Fernández, José Luis; del Carmen Fernández, María; Molina, Francisca; Villanueva, Rosa; Gosálvez, Jaime; Bou, Germán

    2009-08-01

    We recently reported a simple new in situ diffusion assay, developed as a kit, to visualize DNA fragmentation in single bacterial cells. Use of this assay in a collection of 95 genetically unrelated Escherichia coli clinical strains resulted in correct identification of all of the isolates as resistant or susceptible to ciprofloxacin, consistent with the MIC results. This relevant information is obtained in 80 min.

  20. Novel approach to in vitro drug susceptibility assessment of clinical strains of Leishmania spp.

    PubMed

    Fernández, Olga; Diaz-Toro, Yira; Valderrama, Liliana; Ovalle, Clemencia; Valderrama, Mabel; Castillo, Harry; Perez, Mauricio; Saravia, Nancy Gore

    2012-07-01

    Resistance to antimonial drugs has been documented in Leishmania isolates transmitted in South America, Europe, and Asia. The frequency and distribution of resistance to these and other antileishmanial drugs are unknown. Technical constraints have limited the assessment of drug susceptibility of clinical strains of Leishmania. Susceptibility of experimentally selected lines and 130 clinical strains of Leishmania panamensis, L. braziliensis, and L. guyanensis to meglumine antimoniate and miltefosine was determined on the basis of parasite burden and percentage of infected U-937 human macrophages. Reductions of infection at single predefined concentrations of meglumine antimoniate and miltefosine and 50% effective doses (ED(50)s) were measured and correlated. The effects of 34°C and 37°C incubation temperatures and different parasite-to-host cell ratios on drug susceptibility were evaluated at 5, 10, and 20 parasites/cell. Reduction of the intracellular burden of Leishmania amastigotes in U-937 cells exposed to the predefined concentrations of meglumine antimoniate or miltefosine discriminated sensitive and experimentally derived resistant Leishmania populations and was significantly correlated with ED(50) values of clinical strains (for meglumine antimoniate, ρ = -0.926 and P < 0.001; for miltefosine, ρ = -0.906 and P < 0.001). Incubation at 37°C significantly inhibited parasite growth compared to that at 34°C in the absence of antileishmanial drugs and resulted in a significantly lower ED(50) in the presence of drugs. Susceptibility assessment was not altered by the parasite-to-cell ratio over the range evaluated. In conclusion, measurement of the reduction of parasite burden at a single predetermined drug concentration under standardized conditions provides an efficient and reliable strategy for susceptibility evaluation and monitoring of clinical strains of Leishmania.

  1. Novel Approach to In Vitro Drug Susceptibility Assessment of Clinical Strains of Leishmania spp.

    PubMed Central

    Fernández, Olga; Diaz-Toro, Yira; Valderrama, Liliana; Ovalle, Clemencia; Valderrama, Mabel; Castillo, Harry; Perez, Mauricio

    2012-01-01

    Resistance to antimonial drugs has been documented in Leishmania isolates transmitted in South America, Europe, and Asia. The frequency and distribution of resistance to these and other antileishmanial drugs are unknown. Technical constraints have limited the assessment of drug susceptibility of clinical strains of Leishmania. Susceptibility of experimentally selected lines and 130 clinical strains of Leishmania panamensis, L. braziliensis, and L. guyanensis to meglumine antimoniate and miltefosine was determined on the basis of parasite burden and percentage of infected U-937 human macrophages. Reductions of infection at single predefined concentrations of meglumine antimoniate and miltefosine and 50% effective doses (ED50s) were measured and correlated. The effects of 34°C and 37°C incubation temperatures and different parasite-to-host cell ratios on drug susceptibility were evaluated at 5, 10, and 20 parasites/cell. Reduction of the intracellular burden of Leishmania amastigotes in U-937 cells exposed to the predefined concentrations of meglumine antimoniate or miltefosine discriminated sensitive and experimentally derived resistant Leishmania populations and was significantly correlated with ED50 values of clinical strains (for meglumine antimoniate, ρ = −0.926 and P < 0.001; for miltefosine, ρ = −0.906 and P < 0.001). Incubation at 37°C significantly inhibited parasite growth compared to that at 34°C in the absence of antileishmanial drugs and resulted in a significantly lower ED50 in the presence of drugs. Susceptibility assessment was not altered by the parasite-to-cell ratio over the range evaluated. In conclusion, measurement of the reduction of parasite burden at a single predetermined drug concentration under standardized conditions provides an efficient and reliable strategy for susceptibility evaluation and monitoring of clinical strains of Leishmania. PMID:22518860

  2. Assessing phage therapy against Pseudomonas aeruginosa using a Galleria mellonella infection model.

    PubMed

    Beeton, M L; Alves, D R; Enright, M C; Jenkins, A T A

    2015-08-01

    The Galleria mellonella infection model was used to assess the in vivo efficacy of phage therapy against laboratory and clinical strains of Pseudomonas aeruginosa. In a first series of experiments, Galleria were infected with the laboratory strain P. aeruginosa PAO1 and were treated with varying multiplicity of infection (MOI) of phages either 2h post-infection (treatment) or 2h pre-infection (prevention) via injection into the haemolymph. To address the kinetics of infection, larvae were bled over a period of 24h for quantification of bacteria and phages. Survival rates at 24h when infected with 10 cells/larvae were greater in the prevention versus treatment model (47% vs. 40%, MOI=10; 47% vs. 20%, MOI=1; and 33% vs. 7%, MOI=0.1). This pattern held true when 100 cells/larvae were used (87% vs. 20%, MOI=10; 53% vs. 13%, MOI=1; 67% vs. 7%, MOI=0.1). By 24h post-infection, phages kept bacterial cell numbers in the haemolymph 1000-fold lower than in the non-treated group. In a second series of experiments using clinical strains to further validate the prevention model, phages protected Galleria when infected with both a bacteraemia (0% vs. 85%) and a cystic fibrosis (80% vs. 100%) isolate. Therefore, this study validates the use of G. mellonella as a simple, robust and cost-effective model for initial in vivo examination of P. aeruginosa-targeted phage therapy, which may be applied to other pathogens with similarly low infective doses.

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

    PubMed

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

    2014-12-04

    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.

  4. Short Chain N-Acylhomoserine Lactone Production by Clinical Multidrug Resistant Klebsiella pneumoniae Strain CSG20

    PubMed Central

    Ngeow, Yun Fong; Cheng, Huey Jia; Chen, Jian Woon; Yin, Wai-Fong; Chan, Kok-Gan

    2013-01-01

    Klebsiella pneumoniae is one of the most common Gram-negative bacterial pathogens in clinical practice. It is associated with a wide range of disorders, ranging from superficial skin and soft tissue infections to potentially fatal sepsis in the lungs and blood stream. Quorum sensing, or bacterial cell-cell communication, refers to population density-dependent gene expression modulation. Quorum sensing in Proteobacteria relies on the production and sensing of signaling molecules which are mostly N-acylhomoserine lactones. Here, we report the identification of a multidrug resistant clinical isolate, K. pneumoniae strain CSG20, using matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry. We further confirmed quorum sensing activity in this strain with the use of high resolution tandem liquid chromatography quadrupole mass spectrometry and provided evidence K. pneumoniae strain CSG20 produced N-hexanoyl-homoserine lactone (C6-HSL). To the best of our knowledge, this is the first report on the production of N-hexanoylhomoserine lactone (C6-HSL) in clinical isolate K. pneumoniae. PMID:24284772

  5. Clinical testing of engineered oncolytic measles virus strains in the treatment of cancer: An overview

    PubMed Central

    Msaouel, Pavlos; Dispenzieri, Angela; Galanis, Evanthia

    2009-01-01

    Viruses have adapted through millennia of evolution to effectively invade and lyse cells through diverse mechanisms. Strains of the attenuated measles virus Edmonston (MV-Edm) vaccine lineage can preferentially infect and destroy cancerous cells while sparing the surrounding tissues. This specificity is predominantly due to overexpression of the measles virus receptor CD46 in tumor cells. To facilitate in vivo monitoring of viral gene expression and replication, these oncolytic strains have been engineered to either express soluble marker peptides, such as the human carcinoembryonic antigen (CEA; MV-CEA virus), or genes that facilitate imaging and therapy, such as the human thyroidal sodium iodide symporter (NIS) gene (MV-NIS). Preclinical efficacy and safety data for engineered oncolytic MV-Edm derivatives that led to their clinical translation are discussed in this review, and an overview of the early experience in three ongoing clinical trials of patients with ovarian cancer, glioblastoma multiforme and multiple myeloma is provided. The information obtained from these ongoing trials will guide the future clinical application and further development of MV strains as anticancer agents. PMID:19169959

  6. [TL, the new bacteriophage of Pseudomonas aeruginosa and its application for the search of halo-producing bacteriophages].

    PubMed

    Pleteneva, E A; Burkal'tseva, M V; Shaburova, O V; Krylov, S V; Pechnikova, E V; Sokolova, O S; Krylov, V N

    2011-01-01

    The properties of new virulent bacteriophage TL of Pseudomonas aeruginosa belonging to the family Podoviridae (genome size of 46 kb) were investigated. This bacteriophage is capable of lysogenizing the bacterial lawn in halo zones around negative colonies (NC) of other bacteriophages. TL forms large NC, that are hardly distinguishable on the lawn of P. aeruginisa PAO1. At the same time, on the lawns of some phage-resistant PAO1 mutants, as well as on those produced by a number of clinical isolates, TL forms more transparent NC. It is suggested that more effective growth of the bacteriophage TL NC is associated with the differences in outer lipopolysaccharide (LPS) layer of the cell walls of different bacterial strains, as well as of the bacteria inside and outside of the halos. This TL property was used to optimize selection of bacteriophages producing halos around NC on the lawn of P. aeruginosa PAO1. As a result, a group of bacteriophages differing in the patterns of interaction between their halos and TL bacteriophage, as well as in some characters was identified. Taking into consideration the importance of cell-surfaced structures of P. aeruginosa in manifestation of virulence and pathogenicity, possible utilization of specific phage enzymes, polysacchadide depolymerases, for more effective treatment of P. aeruginosa infections is discussed.

  7. Clinical correlations of human cytomegalovirus strains and viral load in kidney transplant recipients.

    PubMed

    Nogueira, Eliana; Ozaki, Kikumi Suzete; Tomiyama, Helena; Câmara, Niels Olsen Saraiva; Granato, Celso Francisco Hernandes

    2009-01-01

    Little is known about clinical differences associated with cytomegalovirus (CMV) infection by distinct strains in renal transplant patients. Different clinical pictures may be associated with specific viral genotypes, viral load, as well as host factors. The objective of this study was to identify CMV strains to determine viral load (antigenemia), and their correlation with clinical data in renal transplant recipients. Seventy-one patients were enrolled, comprising 91 samples. After selection, polymorphonuclear cells were used to amplify and sequence the gB region of CMV DNA. The sequences were analyzed to ascertain the frequency of different genotypes. Additionally, the results of this study showed that the gB coding gene presents a great variability, revealing a variety of patterns: classical gB1 (1.4%), gB1V (46.4%), classical gB2 (35.2%), gB2V (2.8%), gB3 (1.4%), classical gB4 (4.9%) and gB4V (4.9%). The mean viral load in kidney transplant patient was 75.1 positive cells (1-1000). A higher viral load was observed in patients with genotype 4 infection. Statistically significant differences were detected between gB1 and gB4 (p=0.010), and between gB2 and gB4 (p=0.021). The average numbers of positive cells in relation to clinical presentation were: 34.5 in asymptomatic, 49.5 in CMV associated syndrome and 120.7 in patients with invasive disease (p=0.048). As a group, gB1 was the most frequent strain and revealed a potential risk for developing invasive disease. Viral load also seemed to be important as a marker associated with clinical presentation of the disease.

  8. Multilocus Sequence Analysis of Clinical “Candidatus Neoehrlichia mikurensis” Strains from Europe

    PubMed Central

    Grankvist, Anna; Moore, Edward R. B.; Svensson Stadler, Liselott; Pekova, Sona; Bogdan, Christian; Geißdörfer, Walter; Grip-Lindén, Jenny; Brandström, Kenny; Marsal, Jan; Andréasson, Kristofer; Lewerin, Catharina; Welinder-Olsson, Christina

    2015-01-01

    “Candidatus Neoehrlichia mikurensis” is the tick-borne agent of neoehrlichiosis, an infectious disease that primarily affects immunocompromised patients. So far, the genetic variability of “Ca. Neoehrlichia” has been studied only by comparing 16S rRNA genes and groEL operon sequences. We describe the development and use of a multilocus sequence analysis (MLSA) protocol to characterize the genetic diversity of clinical “Ca. Neoehrlichia” strains in Europe and their relatedness to other species within the Anaplasmataceae family. Six genes were selected: ftsZ, clpB, gatB, lipA, groEL, and 16S rRNA. Each MLSA locus was amplified by real-time PCR, and the PCR products were sequenced. Phylogenetic trees of MLSA locus relatedness were constructed from aligned sequences. Blood samples from 12 patients with confirmed “Ca. Neoehrlichia” infection from Sweden (n = 9), the Czech Republic (n = 2), and Germany (n = 1) were analyzed with the MLSA protocol. Three of the Swedish strains exhibited identical lipA sequences, while the lipA sequences of the strains from the other nine patients were identical to each other. One of the Czech strains had one differing nucleotide in the clpB sequence from the sequences of the other 11 strains. All 12 strains had identical sequences for the genes 16S rRNA, ftsZ, gatB, and groEL. According to the MLSA, among the Anaplasmataceae, “Ca. Neoehrlichia” is most closely related to Ehrlichia ruminantium, less so to Anaplasma phagocytophilum, and least to Wolbachia endosymbionts. To conclude, three sequence types of infectious “Ca. Neoehrlichia” were identified: one in the west of Sweden, one in the Czech Republic, and one spread throughout Europe. PMID:26157152

  9. Alginate Lyase Promotes Diffusion of Aminoglycosides through the Extracellular Polysaccharide of Mucoid Pseudomonas aeruginosa

    PubMed Central

    Hatch, Richard A.; Schiller, Neal L.

    1998-01-01

    We demonstrated that a 2% suspension of Pseudomonas aeruginosa alginate completely blocked the diffusion of gentamicin and tobramycin, but not that of carbenicillin, illustrating how alginate production can help protect P. aeruginosa growing within alginate microcolonies in patients with cystic fibrosis (CF) from the effects of aminoglycosides. This aminoglycoside diffusion barrier was degraded with a semipurified preparation of P. aeruginosa alginate lyase, suggesting that this enzyme deserves consideration as an adjunctive agent for CF patients colonized by mucoid strains of P. aeruginosa. PMID:9559826

  10. Pseudomonas aeruginosa Keratitis in Mice: Effects of Topical Bacteriophage KPP12 Administration

    PubMed Central

    Fukuda, Ken; Ishida, Waka; Uchiyama, Jumpei; Rashel, Mohammad; Kato, Shin-ichiro; Morita, Tamae; Muraoka, Asako; Sumi, Tamaki; Matsuzaki, Shigenobu; Daibata, Masanori; Fukushima, Atsuki

    2012-01-01

    The therapeutic effects of bacteriophage (phage) KPP12 in Pseudomonas aeruginosa keratitis were investigated in mice. Morphological analysis showed that phage KPP12 is a member of the family Myoviridae, morphotype A1, and DNA sequence analysis revealed that phage KPP12 is similar to PB1-like viruses. Analysis of the phage KPP12 genome did not identify any genes related to drug resistance, pathogenicity or lysogenicity, and so phage KPP12 may be a good candidate for therapeutic. KPP12 showed a broad host range for P. aeruginosa strains isolated from clinical ophthalmic infections. Inoculation of the scarified cornea with P. aeruginosa caused severe keratitis and eventual corneal perforation. Subsequent single-dose administration of KPP12 eye-drops significantly improved disease outcome, and preserved the structural integrity and transparency of the infected cornea. KPP12 treatment resulted in the suppression of neutrophil infiltration and greatly enhanced bacterial clearance in the infected cornea. These results indicate that bacteriophage eye-drops may be a novel adjunctive or alternative therapeutic agent for the treatment of infectious keratitis secondary to antibiotic-resistant bacteria. PMID:23082205

  11. Contribution of cell elongation to the biofilm formation of Pseudomonas aeruginosa during anaerobic respiration.

    PubMed

    Yoon, Mi Young; Lee, Kang-Mu; Park, Yongjin; Yoon, Sang Sun

    2011-01-18

    Pseudomonas aeruginosa, a gram-negative bacterium of clinical importance, forms more robust biofilm during anaerobic respiration, a mode of growth presumed to occur in abnormally thickened mucus layer lining the cystic fibrosis (CF) patient airway. However, molecular basis behind this anaerobiosis-triggered robust biofilm formation is not clearly defined yet. Here, we identified a morphological change naturally accompanied by anaerobic respiration in P. aeruginosa and investigated its effect on the biofilm formation in vitro. A standard laboratory strain, PAO1 was highly elongated during anaerobic respiration compared with bacteria grown aerobically. Microscopic analysis demonstrated that cell elongation likely occurred as a consequence of defective cell division. Cell elongation was dependent on the presence of nitrite reductase (NIR) that reduces nitrite (NO(2) (-)) to nitric oxide (NO) and was repressed in PAO1 in the presence of carboxy-PTIO, a NO antagonist, demonstrating that cell elongation involves a process to respond to NO, a spontaneous byproduct of the anaerobic respiration. Importantly, the non-elongated NIR-deficient mutant failed to form biofilm, while a mutant of nitrate reductase (NAR) and wild type PAO1, both of which were highly elongated, formed robust biofilm. Taken together, our data reveal a role of previously undescribed cell biological event in P. aeruginosa biofilm formation and suggest NIR as a key player involved in such process.

  12. Molecular characterization of Staphylococcus pseudintermedius strains isolated from clinical samples of animal origin.

    PubMed

    Chrobak, D; Kizerwetter-Świda, M; Rzewuska, M; Moodley, A; Guardabassi, L; Binek, M

    2011-09-01

    The aim of this study was to determine the species distribution among 44 randomly selected clinical isolates (30 mecA-positive and 14 mecA-negative) of animal origin previously identified as Staphylococcus intermedius by phenotypic tests and species-specific PCR amplification of the 16S rRNA gene. For this purpose, we used a multiplex PCR for the detection of the nuc gene and restriction fragment length polymorphism analysis of pta gene amplified by PCR. Both methods allow discrimination of Staphylococcus pseudintermedius from the other closely related members of the S. intermedius group and other coagulase-positive staphylococci isolated from animals. Genetic diversity of S. pseudintermedius strains was analyzed by staphylococcal protein A-encoding gene (spa) typing. Multiplex PCR method was used to identify staphylococcal cassette chromosome mec (SCCmec) type in mecA-positive strains. All isolates previously identified as S. intermedius were shown to belong to S. pseudintermedius. According to PCR-based SCCmec typing, SCCmecIII was the most prevalent type (n = 23), and solely seven isolates were designated as non-typeable. Furthermore, the assessment of spa-typing results revealed that the majority of all strains (n = 27) harbored spa type t02, and 17 strains were classified as non-typeable.

  13. Antibacterial activity of fresh pomegranate juice against clinical strains of Staphylococcus epidermidis

    PubMed Central

    Betanzos-Cabrera, Gabriel; Montes-Rubio, Perla Y.; Fabela-Illescas, Héctor E.; Belefant-Miller, Helen; Cancino-Diaz, Juan C.

    2015-01-01

    Background Polyphenols have received a great deal of attention due to their biological functions. Pomegranate (Punica granatum L.) is a polyphenol-rich fruit. In the past decade, studies testing the antimicrobial activity of pomegranates almost exclusively used solvent extracts instead of fresh pomegranate juice (FPJ). The use of FPJ instead of solvent extracts would reduce toxicity issues while increasing patient acceptance. We established a model to test FPJ as a natural antimicrobial agent. Objective To evaluate the antimicrobial activity of FPJ on clinical isolates of multidrug-resistant Staphylococcus epidermidis strains. Design Sixty strains of S. epidermidis isolated from ocular infections were grown in the presence of FPJ, and minimum inhibitory concentration (MIC) was determined by broth and agar dilution methods. Results FPJ at 20% had a MIC equal to 100% (MIC100%) on all 60 strains tested. This inhibition of FPJ was confirmed by the growth kinetics of a multidrug-resistant strain exposed to different concentrations of FPJ. Additionally, the antimicrobial activity of FPJ was compared against commercial beverages containing pomegranate: Ocean Spray® had a MIC100% at 20%, followed by Del Valle® with a MIC15% at 20% concentration only. The beverages Jumex® and Sonrisa® did not have any antimicrobial activity. FPJ had the highest polyphenol content and antioxidant capacity. Conclusions Overall, FPJ had antimicrobial activity, which might be attributed to its high polyphenol content and antioxidant capacity. PMID:25999265

  14. The Genetic Analysis of an Acinetobacter johnsonii Clinical Strain Evidenced the Presence of Horizontal Genetic Transfer.

    PubMed

    Montaña, Sabrina; Schramm, Sareda T J; Traglia, German Matías; Chiem, Kevin; Parmeciano Di Noto, Gisela; Almuzara, Marisa; Barberis, Claudia; Vay, Carlos; Quiroga, Cecilia; Tolmasky, Marcelo E; Iriarte, Andrés; Ramírez, María Soledad

    2016-01-01

    Acinetobacter johnsonii rarely causes human infections. While most A. johnsonii isolates are susceptible to virtually all antibiotics, strains harboring a variety of β-lactamases have recently been described. An A. johnsonii Aj2199 clinical strain recovered from a hospital in Buenos Aires produces PER-2 and OXA-58. We decided to delve into its genome by obtaining the whole genome sequence of the Aj2199 strain. Genome comparison studies on Aj2199 revealed 240 unique genes and a close relation to strain WJ10621, isolated from the urine of a patient in China. Genomic analysis showed evidence of horizontal genetic transfer (HGT) events. Forty-five insertion sequences and two intact prophages were found in addition to several resistance determinants such as blaPER-2, blaOXA-58, blaTEM-1, strA, strB, ereA, sul1, aacC2 and a new variant of blaOXA-211, called blaOXA-498. In particular, blaPER-2 and blaTEM-1 are present within the typical contexts previously described in the Enterobacteriaceae family. These results suggest that A. johnsonii actively acquires exogenous DNA from other bacterial species and concomitantly becomes a reservoir of resistance genes.

  15. The Genetic Analysis of an Acinetobacter johnsonii Clinical Strain Evidenced the Presence of Horizontal Genetic Transfer

    PubMed Central

    Montaña, Sabrina; Schramm, Sareda T. J.; Traglia, German Matías; Chiem, Kevin; Parmeciano Di Noto, Gisela; Almuzara, Marisa; Barberis, Claudia; Vay, Carlos; Quiroga, Cecilia; Tolmasky, Marcelo E.; Iriarte, Andrés; Ramírez, María Soledad

    2016-01-01

    Acinetobacter johnsonii rarely causes human infections. While most A. johnsonii isolates are susceptible to virtually all antibiotics, strains harboring a variety of β-lactamases have recently been described. An A. johnsonii Aj2199 clinical strain recovered from a hospital in Buenos Aires produces PER-2 and OXA-58. We decided to delve into its genome by obtaining the whole genome sequence of the Aj2199 strain. Genome comparison studies on Aj2199 revealed 240 unique genes and a close relation to strain WJ10621, isolated from the urine of a patient in China. Genomic analysis showed evidence of horizontal genetic transfer (HGT) events. Forty-five insertion sequences and two intact prophages were found in addition to several resistance determinants such as blaPER-2, blaOXA-58, blaTEM-1, strA, strB, ereA, sul1, aacC2 and a new variant of blaOXA-211, called blaOXA-498. In particular, blaPER-2 and blaTEM-1 are present within the typical contexts previously described in the Enterobacteriaceae family. These results suggest that A. johnsonii actively acquires exogenous DNA from other bacterial species and concomitantly becomes a reservoir of resistance genes. PMID:27548264

  16. Pseudomonas aeruginosa ventilator-associated pneumonia management.

    PubMed

    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.

  17. 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

  18. Genetic variability among Chlamydia trachomatis reference and clinical strains analyzed by pulsed-field gel electrophoresis.

    PubMed Central

    Rodriguez, P; Allardet-Servent, A; de Barbeyrac, B; Ramuz, M; Bebear, C

    1994-01-01

    Pulsed-field gel electrophoresis (PFGE) was applied to Chlamydia trachomatis reference strains representing each of the 18 serovars and to 29 clinical isolates from genital specimens collected in Bordeaux, France, or Malmö, Sweden. Comparison of the fingerprint patterns of the reference strains revealed a high level of polymorphism of the total DNA when SmaI was used (14 profiles), whereas the other enzymes, Sse8387I and ApaI, showed fewer differences. Some serovars, considered to be closely related on the basis of their antigenic determinants located on the major outer membrane protein (MOMP), such as D and Da or I and Ia, were shown to be different after PFGE of their genomic DNAs. However, serovars B and Ba and serovars L2 and L2a had identical patterns after analysis with the three endonucleases. When applied to clinical isolates, which were typed by restriction fragment length polymorphism analysis of the MOMP gene, PFGE allowed the detection of intragenotype polymorphisms and showed the identity of two strains successively isolated from the same patient. This technique seems to be an efficient tool for epidemiological studies when used in addition to serotyping or genotyping by restriction fragment length polymorphism analysis of the MOMP gene. Images PMID:7883878

  19. 3D motion and strain estimation of the heart: initial clinical findings

    NASA Astrophysics Data System (ADS)

    Barbosa, Daniel; Hristova, Krassimira; Loeckx, Dirk; Rademakers, Frank; Claus, Piet; D'hooge, Jan

    2010-03-01

    The quantitative assessment of regional myocardial function remains an important goal in clinical cardiology. As such, tissue Doppler imaging and speckle tracking based methods have been introduced to estimate local myocardial strain. Recently, volumetric ultrasound has become more readily available, allowing therefore the 3D estimation of motion and myocardial deformation. Our lab has previously presented a method based on spatio-temporal elastic registration of ultrasound volumes to estimate myocardial motion and deformation in 3D, overcoming the spatial limitations of the existing methods. This method was optimized on simulated data sets in previous work and is currently tested in a clinical setting. In this manuscript, 10 healthy volunteers, 10 patient with myocardial infarction and 10 patients with arterial hypertension were included. The cardiac strain values extracted with the proposed method were compared with the ones estimated with 1D tissue Doppler imaging and 2D speckle tracking in all patient groups. Although the absolute values of the 3D strain components assessed by this new methodology were not identical to the reference methods, the relationship between the different patient groups was similar.

  20. Susceptibility to antifungal agents and genotypes of Brazilian clinical and environmental Cryptococcus gattii strains.

    PubMed

    Silva, Dayane C; Martins, Marilena A; Szeszs, Maria Walderez; Bonfietti, Lucas X; Matos, Dulcilena; Melhem, Marcia S C

    2012-04-01

    There are few reports concerning the in vitro antifungal susceptibility of clinical and environmental Cryptococcus gattii isolates. In this study, we performed polymerase chain reaction-restriction fragment length polymorphism to investigate the molecular subtypes of 50 clinical and 4 environmental Brazilian isolates of C. gattii and assessed their antifungal susceptibility for fluconazole (FLU) and amphotericin B (Amb) according to recent recommendations proposed for antifungal susceptibility testing of nonfermentative yeasts. Time-kill curve studies were performed using RPMI 1640 medium to analyze the fungicidal effect of AmB. We found 47 VGII (94%) molecular types and 3 VGI (6%) types among the clinical isolates. The environmental isolates were VGII (75%) subtype and VGI (25%) subtype. The FLU-MIC ranged from 1 to 64 mg L(-1), and MIC(50)/MIC(90) values were, respectively, 8/16 mg L(-1). For AmB, the MICs were low and homogeneous, ranging from 0.12 to 0.5 mg L(-1), for VGI or VGII. The time required to reach the fungicidal end point (99.9% killing) was 6 h for the majority of strains (64%), but viable cells of VGII were still present after 48 h of exposition. We pointed out the occurrence of high FLU-MICs for C. gattii isolates with highest values for VGII. Our data also suggest that the rate of killing of C. gattii by AmB is strain dependent, and viable cells of VGII genotype strains were still observed after an extended incubation time, addressing future studies to determine whether the in vitro fungicidal activity could be clinically relevant.

  1. Clinical distribution and antibiotic sensitivities of staphylococcal strains isolated over an eight-month period.

    PubMed Central

    Varaldo, P E; Soro, O; Grazi, G; Biavasco, F

    1981-01-01

    A total of 842 staphylococci isolated from clinical material over an eight-month period and regarded as probable pathogens were identified according to lyogroup. Almost half the isolates belonged to lyogroups other than lyogroup I (Staphylococcus aureus), suggesting that coagulase-negative staphylococci are increasingly involved in human infections. All isolates were tested for sensitivity to 12 antibiotics. A greater resistance was observed in non-lyogroup I isolates, which again suggests a pathogenic significance of coagulase-negative staphylococci. Only lyogroup I strains, however, were obtained more frequently from clinical isolates than from healthy human skin. The distribution of the isolates in each lyogroup according to their clinical source is reported. PMID:7240433

  2. Characterization of Vibrio parahaemolyticus clinical strains from Maryland (2012–2013) and comparisons to a locally and globally diverse V. parahaemolyticus strains by whole-genome sequence analysis

    PubMed Central

    Haendiges, Julie; Timme, Ruth; Allard, Marc W.; Myers, Robert A.; Brown, Eric W.; Gonzalez-Escalona, Narjol

    2015-01-01

    Vibrio parahaemolyticus is the leading cause of foodborne illnesses in the US associated with the consumption of raw shellfish. Previous population studies of V. parahaemolyticus have used Multi-Locus Sequence Typing (MLST) or Pulsed Field Gel Electrophoresis (PFGE). Whole genome sequencing (WGS) provides a much higher level of resolution, but has been used to characterize only a few United States (US) clinical isolates. Here we report the WGS characterization of 34 genomes of V. parahaemolyticus strains that were isolated from clinical cases in the state of Maryland (MD) during 2 years (2012–2013). These 2 years saw an increase of V. parahaemolyticus cases compared to previous years. Among these MD isolates, 28% were negative for tdh and trh, 8% were tdh positive only, 11% were trh positive only, and 53% contained both genes. We compared this set of V. parahaemolyticus genomes to those of a collection of 17 archival strains from the US (10 previously sequenced strains and 7 from NCBI, collected between 1988 and 2004) and 15 international strains, isolated from geographically-diverse environmental and clinical sources (collected between 1980 and 2010). A WGS phylogenetic analysis of these strains revealed the regional outbreak strains from MD are highly diverse and yet genetically distinct from the international strains. Some MD strains caused outbreaks 2 years in a row, indicating a local source of contamination (e.g., ST631). Advances in WGS will enable this type of analysis to become routine, providing an excellent tool for improved surveillance. Databases built with phylogenetic data will help pinpoint sources of contamination in future outbreaks and contribute to faster outbreak control. PMID:25745421

  3. Strong incidence of Pseudomonas aeruginosa on bacterial rrs and ITS genetic structures of cystic fibrosis sputa

    PubMed Central

    Pages-Monteiro, Laurence; Marti, Romain; Commun, Carine; Alliot, Nolwenn; Bardel, Claire; Meugnier, Helene; Perouse-de-Montclos, Michele; Reix, Philippe; Durieu, Isabelle; Durupt, Stephane; Vandenesch, Francois; Freney, Jean; Cournoyer, Benoit; Doleans-Jordheim, Anne

    2017-01-01

    Cystic fibrosis (CF) lungs harbor a complex community of interacting microbes, including pathogens like Pseudomonas aeruginosa. Meta-taxogenomic analysis based on V5-V6 rrs PCR products of 52 P. aeruginosa-positive (Pp) and 52 P. aeruginosa-negative (Pn) pooled DNA extracts from CF sputa suggested positive associations between P. aeruginosa and Stenotrophomonas and Prevotella, but negative ones with Haemophilus, Neisseria and Burkholderia. Internal Transcribed Spacer analyses (RISA) from individual DNA extracts identified three significant genetic structures within the CF cohorts, and indicated an impact of P. aeruginosa. RISA clusters Ip and IIIp contained CF sputa with a P. aeruginosa prevalence above 93%, and of 24.2% in cluster IIp. Clusters Ip and IIIp showed lower RISA genetic diversity and richness than IIp. Highly similar cluster IIp RISA profiles were obtained from two patients harboring isolates of a same P. aeruginosa clone, suggesting convergent evolution in the structure of their microbiota. CF patients of cluster IIp had received significantly less antibiotics than patients of clusters Ip and IIIp but harbored the most resistant P. aeruginosa strains. Patients of cluster IIIp were older than those of Ip. The effects of P. aeruginosa on the RISA structures could not be fully dissociated from the above two confounding factors but several trends in these datasets support the conclusion of a strong incidence of P. aeruginosa on the genetic structure of CF lung microbiota. PMID:28282386

  4. Dynamics of Clinical and Environmental Vibrio parahaemolyticus Strains during Seafood-Related Summer Diarrhea Outbreaks in Southern Chile ▿

    PubMed Central

    García, Katherine; Torres, Rafael; Uribe, Paulina; Hernández, Cristina; Rioseco, M. Luisa; Romero, Jaime; Espejo, Romilio T.

    2009-01-01

    Seafood consumption-related diarrhea became prevalent in Chile when the pandemic strain of Vibrio parahaemolyticus serotype O3:K6 reached a region in the south of Chile (Region de los Lagos) where approximately 80% of the country's seafood is produced. In spite of the large outbreaks of clinical infection, the load of V. parahaemolyticus in shellfish of this region is relatively low. The pandemic strain constitutes a small but relatively stable group of a diverse V. parahaemolyticus population, composed of at least 28 genetic groups. Outbreaks in Region de los Lagos began in 2004 and reached a peak in 2005 with 3,725 clinical cases, all associated with the pandemic strain. After 2005, reported cases steadily decreased to a total of 477 cases in 2007. At that time, 40% of the clinical cases were associated with a pandemic strain of a different serotype (O3:K59), and 27% were related to V. parahaemolyticus isolates unrelated to the pandemic strain. In the results published here, we report that in the summer of 2008, when reported cases unexpectedly increased from 477 to 1,143, 98% of the clinical cases were associated with the pandemic strain serotype O3:K6, a change from 2007. Nevertheless, in 2009, when clinical cases decreased to 441, only 64% were related to the pandemic strain; the remaining cases were related to a nonpandemic tdh- and trh-negative strain first identified in shellfish in 2006. Overall, our observations indicate that the pandemic strain has become a relatively stable subpopulation and that when the number of diarrhea cases related to the pandemic strain is low, previously undetected V. parahaemolyticus pathogenic strains become evident. PMID:19801458

  5. Dynamics of clinical and environmental Vibrio parahaemolyticus strains during seafood-related summer diarrhea outbreaks in southern Chile.

    PubMed

    García, Katherine; Torres, Rafael; Uribe, Paulina; Hernández, Cristina; Rioseco, M Luisa; Romero, Jaime; Espejo, Romilio T

    2009-12-01

    Seafood consumption-related diarrhea became prevalent in Chile when the pandemic strain of Vibrio parahaemolyticus serotype O3:K6 reached a region in the south of Chile (Region de los Lagos) where approximately 80% of the country's seafood is produced. In spite of the large outbreaks of clinical infection, the load of V. parahaemolyticus in shellfish of this region is relatively low. The pandemic strain constitutes a small but relatively stable group of a diverse V. parahaemolyticus population, composed of at least 28 genetic groups. Outbreaks in Region de los Lagos began in 2004 and reached a peak in 2005 with 3,725 clinical cases, all associated with the pandemic strain. After 2005, reported cases steadily decreased to a total of 477 cases in 2007. At that time, 40% of the clinical cases were associated with a pandemic strain of a different serotype (O3:K59), and 27% were related to V. parahaemolyticus isolates unrelated to the pandemic strain. In the results published here, we report that in the summer of 2008, when reported cases unexpectedly increased from 477 to 1,143, 98% of the clinical cases were associated with the pandemic strain serotype O3:K6, a change from 2007. Nevertheless, in 2009, when clinical cases decreased to 441, only 64% were related to the pandemic strain; the remaining cases were related to a nonpandemic tdh- and trh-negative strain first identified in shellfish in 2006. Overall, our observations indicate that the pandemic strain has become a relatively stable subpopulation and that when the number of diarrhea cases related to the pandemic strain is low, previously undetected V. parahaemolyticus pathogenic strains become evident.

  6. Identification and Characterization of Inhibitors of Multidrug Resistance Efflux Pumps in Pseudomonas aeruginosa: Novel Agents for Combination Therapy

    PubMed Central

    Lomovskaya, Olga; Warren, Mark S.; Lee, Angela; Galazzo, Jorge; Fronko, Richard; Lee, May; Blais, Johanne; Cho, Deidre; Chamberland, Suzanne; Renau, Tom; Leger, Roger; Hecker, Scott; Watkins, Will; Hoshino, Kazuki; Ishida, Hiroko; Lee, Ving J.

    2001-01-01

    Whole-cell assays were implemented to search for efflux pump inhibitors (EPIs) of the three multidrug resistance efflux pumps (MexAB-OprM, MexCD-OprJ, MexEF-OprN) that contribute to fluoroquinolone resistance in clinical isolates of Pseudomonas aeruginosa. Secondary assays were developed to identify lead compounds with exquisite activities as inhibitors. A broad-spectrum EPI which is active against all three known Mex efflux pumps from P. aeruginosa and their close Escherichia coli efflux pump homolog (AcrAB-TolC) was discovered. When this compound, MC-207,110, was used, the intrinsic resistance of P. aeruginosa to fluoroquinolones was decreased significantly (eightfold for levofloxacin). Acquired resistance due to the overexpression of efflux pumps was also decreased (32- to 64-fold reduction in the MIC of levofloxacin). Similarly, 32- to 64-fold reductions in MICs in the presence of MC-207,110 were observed for strains with overexpressed efflux pumps and various target mutations that confer resistance to levofloxacin (e.g., gyrA and parC). We also compared the frequencies of emergence of levofloxacin-resistant variants in the wild-type strain at four times the MIC of levofloxacin (1 μg/ml) when it was used either alone or in combination with EPI. In the case of levofloxacin alone, the frequency was ∼10−7 CFU/ml. In contrast, with an EPI, the frequency was below the level of detection (<10−11). In summary, we have demonstrated that inhibition of efflux pumps (i) decreased the level of intrinsic resistance significantly, (ii) reversed acquired resistance, and (iii) resulted in a decreased frequency of emergence of P. aeruginosa strains that are highly resistant to fluoroquinolones. PMID:11120952

  7. Short communication: Fluoroquinolone susceptibility of Staphylococcus aureus strains isolated from caprine clinical mastitis in southeast Spain.

    PubMed

    Marín, P; Escudero, E; Fernández-Varón, E; Cárceles, C M; Corrales, J C; Gómez-Martín, A; Martínez, I

    2010-11-01

    The antibiotic susceptibility of 32 strains of Staphylococcus aureus isolated from the mastitic milk of dairy goats was evaluated. The antibiotics tested were 3 fluoroquinolones that have been developed especially for use in veterinary medicine: danofloxacin, marbofloxacin, and orbifloxacin. Minimum inhibitory concentration (MIC) tests were performed according to the microdilution broth method. The MIC(90) (concentration at which 90% inhibition is achieved) values obtained were 0.5, 1, and 1 mg/L for danofloxacin, marbofloxacin, and orbifloxacin, respectively. Danofloxacin was the most active fluoroquinolone tested against Staph. aureus strains isolated from milk; however, specific testing is required before using these drugs as therapy for the control of clinical mammary infections in goats.

  8. Increased conjugation frequencies in clinical Enterococcus faecium strains harbouring the enterococcal surface protein gene esp.

    PubMed

    Lund, B; Billström, H; Edlund, C

    2006-06-01

    This study compared the in-vitro ability of Enterococcus faecium isolates of different origin to acquire vanA by conjugation in relation to the occurrence of the esp gene. In total, 29 clinical isolates (15/29 esp+), 30 normal intestinal microflora isolates (2/30 esp+) and one probiotic strain (esp-) were studied with a filter-mating assay. Conjugation events were confirmed by PCR and pulsed-field gel electrophoresis. Among the infection-derived isolates, the esp+ isolates had higher conjugation frequencies compared with esp- isolates (p < 0.001), with a median value of 6.4 x 10(-6) transconjugants/donor. The probiotic strain was shown to acquire vanA vancomycin resistance in in-vitro filter mating experiments.

  9. Genetic diversity of genes encoding OKP and LEN beta-lactamases produced by clinical Klebsiella pneumoniae strains in Portugal.

    PubMed

    Mendonça, Nuno; Ferreira, Eugénia; Caniça, Manuela

    2009-03-01

    Of the 308 clinical Klebsiella pneumoniae strains collected in 21 Portuguese health institutions, 11 encoded for LEN and 9 for OKP enzymes; of these, 15 were new enzymes. Ninety-one percent of LEN and all OKP producer strains were resistant to amoxicillin. We demonstrate that these beta-lactamase were highly diverse.

  10. Importance of the exopolysaccharide matrix in antimicrobial tolerance of Pseudomonas aeruginosa aggregates.