Antagonistic effect of Pseudomonas aeruginosa isolates from various ecological niches on Vibrio species pathogenic to crustaceans

Institute of Scientific and Technical Information of China (English)

Prabhakaran Priyaja; Puthumana Jayesh; Neil Scolastin Correya; Balachandran Sreelakshmi; Naduthalmuriparambil S Sudheer; Rosamma Philip; Isaac Sarogeni Bright Singh

2014-01-01

Objective: To abrogate pathogenic vibrios in aquaculture by testing the potential of Pseudomonas isolates from fresh water, brackish and marine environments as probiotics.Methods:Antagonistic activity of the compound against 7 Vibrio spp. was performed. Influence of salinity on the production of pyocyanin and the toxicity was done through the compound using brine shrimp lethality assay. Molecular characterization was performed to confirm that the isolates werePseudomonas aeruginosa. Results: Salinity was found to regulate the levels of pyocyanin production, with 5-10 g/L as the optimum. All Pseudomonas isolates grew at salinities ranging from 5 to 70 g/L. Isolates of marine origin produced detectable levels of pyocyanin up to 45 g/L salinity. Brackish and freshwater isolates ceased to produce pyocyanin at salinities above 30 g/L and 20 g/L, respectively. Culture supernatants of all 5 Pseudomonas isolates possessed the ability to restrict the growth of Vibrio spp. and maximum antagonistic effect on Vibrio harveyi was obtained when they were grown at salinities of 5 to 10 g/L. The marine isolate MCCB117, even when grown at a salinity of 45 g/L possessed the ability to inhibit Vibrio spp.Conclusions:Purification and structural elucidation of antagonistic compound were carried out. ideal for application in freshwater, MCCB102 and MCCB103 in brackish water and MCCB117 and The present investigation showed that Pseudomonas aeruginosa MCCB119 would be MCCB118 in marine aquaculture systems as putative probiotics in the management of vibrios.

Pseudomonas aeruginosa biofilm infections

DEFF Research Database (Denmark)

Tolker-Nielsen, Tim

2014-01-01

Bacteria in natural, industrial and clinical settings predominantly live in biofilms, i.e., sessile structured microbial communities encased in self-produced extracellular matrix material. One of the most important characteristics of microbial biofilms is that the resident bacteria display...... a remarkable increased tolerance toward antimicrobial attack. Biofilms formed by opportunistic pathogenic bacteria are involved in devastating persistent medical device-associated infections, and chronic infections in individuals who are immune-compromised or otherwise impaired in the host defense. Because...... the use of conventional antimicrobial compounds in many cases cannot eradicate biofilms, there is an urgent need to develop alternative measures to combat biofilm infections. The present review is focussed on the important opportunistic pathogen and biofilm model organism Pseudomonas aeruginosa. Initially...

Pseudomonas aeruginosa Infections in a Tertiary Hospital in Nigeria ...

African Journals Online (AJOL)

Background: Pseudomonas aeruginosa is a known opportunistic pathogen frequently causing serious infections. It exhibits innate resistance to a wide range of antibiotics thus causing high rates of morbidity and mortality worldwide. Objective: This study was done to determine the distribution and the antibiotic susceptibility ...

Antagonistic effect of Pseudomonas aeruginosa isolates from various ecological niches on Vibrio species pathogenic to crustaceans

Directory of Open Access Journals (Sweden)

Prabhakaran Priyaja

2014-01-01

Full Text Available Objective: To abrogate pathogenic vibrios in aquaculture by testing the potential of Pseudomonas isolates from fresh water, brackish and marine environments as probiotics. Methods: Purification and structural elucidation of antagonistic compound were carried out. Antagonistic activity of the compound against 7 Vibrio spp. was performed. Influence of salinity on the production of pyocyanin and the toxicity was done through the compound using brine shrimp lethality assay. Molecular characterization was performed to confirm that the isolates were Pseudomonas aeruginosa. Results: Salinity was found to regulate the levels of pyocyanin production, with 5-10 g/L as the optimum. All Pseudomonas isolates grew at salinities ranging from 5 to 70 g/L. Isolates of marine origin produced detectable levels of pyocyanin up to 45 g/L salinity. Brackish and freshwater isolates ceased to produce pyocyanin at salinities above 30 g/L and 20 g/L, respectively. Culture supernatants of all 5 Pseudomonas isolates possessed the ability to restrict the growth of Vibrio spp. and maximum antagonistic effect on Vibrio harveyi was obtained when they were grown at salinities of 5 to 10 g/L. The marine isolate MCCB117, even when grown at a salinity of 45 g/L possessed the ability to inhibit Vibrio spp. Conclusions: The present investigation showed that Pseudomonas aeruginosa MCCB119 would be ideal for application in freshwater, MCCB102 and MCCB103 in brackish water and MCCB117 and MCCB118 in marine aquaculture systems as putative probiotics in the management of vibrios.

Pseudomoniasis phytotherapy: A review on most important Iranian medicinal plants effective on Pseudomonas aeruginosa

OpenAIRE

Mahmoud Bahmani; Mahmoud Rafieian-Kopaei; Hassan Hassanzadazar; Morovat Taherikalani

2016-01-01

Background and Objectives: Pseudomonas aeruginosa is a Gram-negative, aerobic bacterium found in water and soil. It is a normal flora in skin and gastrointestinal tract of human beings. P. aeruginosa as an opportunistic pathogen involved in nosocomial infections having multiple pathogenic factors and shows high rate of resistance to different antibiotics. The aim of this study was to identify the most important native medicinal plants of Iran effective on P. aeruginosa.Materials and Methods: ...

Potent Antibacterial Antisense Peptide-Peptide Nucleic Acid Conjugates Against Pseudomonas aeruginosa

DEFF Research Database (Denmark)

Ghosal, Anubrata; Nielsen, Peter E

2012-01-01

Pseudomonas aeruginosa is an opportunistic pathogen causing severe infections in hospital settings, especially with immune compromised patients, and the increasing prevalence of multidrug resistant strains urges search for new drugs with novel mechanisms of action. In this study we introduce...... significantly reduced bacterial survival. These results open the possibility of development of antisense antibacterials for treatment of Pseudomonas infections....

The opportunistic pathogen Pseudomonas aeruginosa activates the DNA double-strand break signaling and repair pathway in infected cells

International Nuclear Information System (INIS)

Elsen, S.; Collin-Faure, V.; Gidrol, X.; Lemercier, C.

2013-01-01

Highly hazardous DNA double-strand breaks can be induced in eukaryotic cells by a number of agents including pathogenic bacterial strains. We have investigated the genotoxic potential of Pseudomonas aeruginosa, an opportunistic pathogen causing devastating nosocomial infections in cystic fibrosis or immunocompromised patients. Our data revealed that infection of immune or epithelial cells by P. aeruginosa triggered DNA strand breaks and phosphorylation of histone H2AX (γH2AX), a marker of DNA double-strand breaks. Moreover, it induced formation of discrete nuclear repair foci similar to gamma-irradiation-induced foci, and containing γH2AX and 53BP1, an adaptor protein mediating the DNA-damage response pathway. Gene deletion, mutagenesis, and complementation in P. aeruginosa identified ExoS bacterial toxin as the major factor involved in γH2AX induction. Chemical inhibition of several kinases known to phosphorylate H2AX demonstrated that Ataxia Telangiectasia Mutated (ATM) was the principal kinase in P. aeruginosa-induced H2AX phosphorylation. Finally, infection led to ATM kinase activation by an auto-phosphorylation mechanism. Together, these data show for the first time that infection by P. aeruginosa activates the DNA double-strand break repair machinery of the host cells. This novel information sheds new light on the consequences of P. aeruginosa infection in mammalian cells. As pathogenic Escherichia coli or carcinogenic Helicobacter pylori can alter genome integrity through DNA double-strand breaks, leading to chromosomal instability and eventually cancer, our findings highlight possible new routes for further investigations of P. aeruginosa in cancer biology and they identify ATM as a potential target molecule for drug design. (authors)

Pseudomonas aeruginosa PA14 pathogenesis in Caenorhabditis elegans.

Science.gov (United States)

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

2014-01-01

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

Genome-wide screen of Pseudomonas aeruginosa In Saccharomyces cerevisiae identifies new virulence factors

Directory of Open Access Journals (Sweden)

Rafat eZrieq

2015-11-01

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

Pseudomonas aeruginosa Trent and zinc homeostasis.

Science.gov (United States)

Davies, Corey B; Harrison, Mark D; Huygens, Flavia

2017-09-01

Pseudomonas aeruginosa is a Gram-negative pathogen and the major cause of mortality in patients with cystic fibrosis. The mechanisms that P. aeruginosa strains use to regulate intracellular zinc have an effect on infection, antibiotic resistance and the propensity to form biofilms. However, zinc homeostasis in P. aeruginosa strains of variable infectivity has not been compared. In this study, zinc homeostasis in P. aeruginosa Trent, a highly infectious clinical strain, was compared to that of a laboratory P. aeruginosa strain, ATCC27853. Trent was able to tolerate higher concentrations of additional zinc in rich media than ATCC27853. Further, pre-adaptation to additional zinc enhanced the growth of Trent at non-inhibitory concentrations but the impact of pre-adaption on the growth of ATCC27853 under the same conditions was minimal. The results establish clear differences in zinc-induced responses in Trent and ATCC27853, and how zinc homeostasis can be a promising target for the development of novel antimicrobial strategies for P. aeruginosa infection in cystic fibrosis patients. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

DEFF Research Database (Denmark)

Thomsen, Kim; Christophersen, Lars; Jensen, Peter Østrup

2016-01-01

Moderation of polymorphonuclear neutrophils (PMNs) as part of a critical defense against invading pathogens may offer a promising therapeutic approach to supplement the antibiotic eradication of Pseudomonas aeruginosa infection in non-chronically infected cystic fibrosis (CF) patients. We have...... observed that egg yolk antibodies (IgY) harvested from White leghorn chickens that target P. aeruginosa opsonize the pathogen and enhance the PMN-mediated respiratory burst and subsequent bacterial killing in vitro. The effects on PMN phagocytic activity were observed in different Pseudomonas aeruginosa...

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

International Nuclear Information System (INIS)

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

1990-01-01

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

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

LENUS (Irish Health Repository)

Linnane, Barry

2015-10-01

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

Silver against Pseudomonas aeruginosa biofilms

DEFF Research Database (Denmark)

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

2007-01-01

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

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

Science.gov (United States)

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

2015-02-10

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

PAMDB: a comprehensive Pseudomonas aeruginosa metabolome database.

Science.gov (United States)

Huang, Weiliang; Brewer, Luke K; Jones, Jace W; Nguyen, Angela T; Marcu, Ana; Wishart, David S; Oglesby-Sherrouse, Amanda G; Kane, Maureen A; Wilks, Angela

2018-01-04

The Pseudomonas aeruginosaMetabolome Database (PAMDB, http://pseudomonas.umaryland.edu) is a searchable, richly annotated metabolite database specific to P. aeruginosa. P. aeruginosa is a soil organism and significant opportunistic pathogen that adapts to its environment through a versatile energy metabolism network. Furthermore, P. aeruginosa is a model organism for the study of biofilm formation, quorum sensing, and bioremediation processes, each of which are dependent on unique pathways and metabolites. The PAMDB is modelled on the Escherichia coli (ECMDB), yeast (YMDB) and human (HMDB) metabolome databases and contains >4370 metabolites and 938 pathways with links to over 1260 genes and proteins. The database information was compiled from electronic databases, journal articles and mass spectrometry (MS) metabolomic data obtained in our laboratories. For each metabolite entered, we provide detailed compound descriptions, names and synonyms, structural and physiochemical information, nuclear magnetic resonance (NMR) and MS spectra, enzymes and pathway information, as well as gene and protein sequences. The database allows extensive searching via chemical names, structure and molecular weight, together with gene, protein and pathway relationships. The PAMBD and its future iterations will provide a valuable resource to biologists, natural product chemists and clinicians in identifying active compounds, potential biomarkers and clinical diagnostics. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Generalized Growth of Estuarine, Household and Clinical Isolates of Pseudomonas aeruginosa

OpenAIRE

Kelly E. Diaz; Susanna K. Remold; Ogochukwu Onyiri; Maura Bozeman; Peter A. Raymond; Paul E. Turner; Paul E. Turner

2018-01-01

Pseudomonas aeruginosa is an opportunistic pathogen of particular concern to immune-compromised people, such as cystic fibrosis patients and burn victims. These bacteria grow in built environments including hospitals and households, and in natural environments such as rivers and estuaries. However, there is conflicting evidence whether recent environments like the human lung and open ocean affect P. aeruginosa growth performance in alternate environments. We hypothesized that bacteria recentl...

Pseudomonas aeruginosa diversity in distinct paediatric patient groups

DEFF Research Database (Denmark)

Tramper-Stranders, G.A.; Ent, C.K. van der; Wolfs, T.F.

2008-01-01

the other groups. A group of clonal isolates was observed among patients from the CF-chronic and CF-1 groups. These or different clonal isolates were not encountered among the three other patient groups. No characteristic resistance pattern could be identified among isolates from the distinct patient groups......Pseudomonas aeruginosa is a pathogen that often infects patients who are either immunocompromised or have local defects in host defences. It is known that cystic fibrosis (CF) patients are sometimes infected with certain clonal isolates. It is not clear whether these clonal isolates also infect non......-CF patients and whether clonality of isolates occurs in other patient groups. The aim of this study was to investigate P. aeruginosa diversity and the occurrence of clones within five distinct paediatric patient groups susceptible to P. aeruginosa infection. P. aeruginosa isolates were cultured from 157...

Quorum quenching by an N-acyl-homoserine lactone acylase from Pseudomonas aeruginosa PAO1

NARCIS (Netherlands)

Sio, CF; Otten, LG; Cool, RH; Diggle, SP; Braun, PG; Daykin, M; Camara, M; Williams, P; Quax, WJ; Bos, R

The virulence of the opportunistic human pathogen Pseudomonas aeruginosa PAO1 is controlled by an N-acyl-homoserine lactone (AHL)-dependent quorum-sensing system. During functional analysis of putative acylase genes in the P. aeruginosa PAO1 genome, the PA2385 gene was found to encode an acylase

Identification of outer membrane Porin D as a vitronectin-binding factor in cystic fibrosis clinical isolates of Pseudomonas aeruginosa

DEFF Research Database (Denmark)

Paulsson, Magnus; Singh, Birendra; Al-Jubair, Tamim

2015-01-01

BACKGROUND: Pseudomonas aeruginosa is a pathogen that frequently colonizes patients with cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD). Several pathogens are known to bind vitronectin to increase their virulence. Vitronectin has been shown to enhance P. aeruginosa adhesion...

Pseudomonas aeruginosa: evaluation of pathogen burden and drug-resistance trends in a tertiary care hospital

International Nuclear Information System (INIS)

Saeed, M.; Hussain, S.; Ahmad, A.

2018-01-01

To evaluate the pathogen burden and antibiotic-resistance trends of Pseudomonas aeruginosa among hospitalised patients at a tertiary care hospital. Study Design:Retrospective, hospital record-based, cross-sectional study. Place and Duration of Study:Microbiology Laboratory, Allama Iqbal Medical College/Jinnah Hospital, Lahore, from January 2014 to December 2016. Methodology:A total of 5,960 samples were collected from clinically suspected cases of bacterial infections, admitted to the hospital. Microbial identification and antibiotic susceptibility pattern were carried out and analysed. Results:Out of a total of 5,960 samples, Pseudomonas aeruginosawas isolated from 1,268 (21.2%) specimens. Department-wise isolation rate was n=600 (42.9%), n=268 (15.4%), n=201 (12.6%), and n=199 (16.0%) from intensive care unit (ICU), surgical units, medical units, and Gynae wards, respectively (p<0.0001). Sample-wise isolation rate was, wound swabs n=448 (35%), urine n=356 (28%), sputum n=187 (14 %), tracheal aspirate n=127 (10%), blood n=99 (7%), and broncho-alveolar lavage n=51 (4%) (p<0.0001). Drug-resistance pattern showed low rates for carbapenems (meropenem n=440 (35%), Imipenem n=436 (34%) and beta-lactam + beta-lactamase inhibitor combination (piperacillin+ tazobactam n=437 (34%) while alarming rates were observed for cephalosporins (ceftazidime n=716 (56%), fluoroquinolones (ciprofloxacin n=690 (54%), cefoperazone+sulbactam n=685 (54%), aminoglycosides (gentamicin, n=669 (53%), amikacin n=608 (48%), and monobactams (aztreonam n=666 (52%). Decreasing trend was observed only for amikacin 63% to 37%, aztreonam showed similar pattern throughout, while there was an increasing trend of drug resistance in all groups of antibiotics. Conclusion:Emerging drug-resistant strains of Pseudomonas aeruginosaare probably linked to the injudicious use of antibiotics, leading to ineffective empirical therapy. Therefore, we suggest that culture and antimicrobial susceptibility testing should

Genomics of adaptation during experimental evolution of the opportunistic pathogen Pseudomonas aeruginosa.

Directory of Open Access Journals (Sweden)

Alex Wong

2012-09-01

Full Text Available Adaptation is likely to be an important determinant of the success of many pathogens, for example when colonizing a new host species, when challenged by antibiotic treatment, or in governing the establishment and progress of long-term chronic infection. Yet, the genomic basis of adaptation is poorly understood in general, and for pathogens in particular. We investigated the genetics of adaptation to cystic fibrosis-like culture conditions in the presence and absence of fluoroquinolone antibiotics using the opportunistic pathogen Pseudomonas aeruginosa. Whole-genome sequencing of experimentally evolved isolates revealed parallel evolution at a handful of known antibiotic resistance genes. While the level of antibiotic resistance was largely determined by these known resistance genes, the costs of resistance were instead attributable to a number of mutations that were specific to individual experimental isolates. Notably, stereotypical quinolone resistance mutations in DNA gyrase often co-occurred with other mutations that, together, conferred high levels of resistance but no consistent cost of resistance. This result may explain why these mutations are so prevalent in clinical quinolone-resistant isolates. In addition, genes involved in cyclic-di-GMP signalling were repeatedly mutated in populations evolved in viscous culture media, suggesting a shared mechanism of adaptation to this CF-like growth environment. Experimental evolutionary approaches to understanding pathogen adaptation should provide an important complement to studies of the evolution of clinical isolates.

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

NARCIS (Netherlands)

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

2011-01-01

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

Occurrence of pseudomonas aeruginosa in post-operative wound infection

International Nuclear Information System (INIS)

Oguntibeju, O.O.; Nwobu, R.A.U.

2004-01-01

Objective: To determine the prevalence of Pseudomonas aeruginosa in post-operative wound infection. Results: Out of the 60 bacterial isolates found in post-operative wound infection, 20 (33.3%) were Pseudomonas aeruginosa, followed by Staphylococcus aureus 13(21.7%), Klebsiella species 10(16.7%), Escherichia coli 7(11.7%), Atypical coliform 4(6.7%), Proteus species 4(6.7%), Streptococcus pyogenes 1(1.7%) and Enterococcus faecalis 1(1.7%) in the order. Pseudomonas aeruginosa infections was higher in female than male, ratio 3:2 and was found more among young and elderly debilitated patients. The in vitro sensitivity pattern of 20 isolates of Pseudomonas aeruginosa showed colistin (100%), gentamicin (75%), streptomycin (30%), and tetracycline (10%). Conclusion: The role of Pseudomonas aeruginosa as an agent of nosocomial infection is re-emphasised. (author)

Pseudomonas aeruginosa ExoU augments neutrophil transepithelial migration.

Science.gov (United States)

Pazos, Michael A; Lanter, Bernard B; Yonker, Lael M; Eaton, Alex D; Pirzai, Waheed; Gronert, Karsten; Bonventre, Joseph V; Hurley, Bryan P

2017-08-01

Excessive neutrophil infiltration of the lungs is a common contributor to immune-related pathology in many pulmonary disease states. In response to pathogenic infection, airway epithelial cells produce hepoxilin A3 (HXA3), initiating neutrophil transepithelial migration. Migrated neutrophils amplify this recruitment by producing a secondary gradient of leukotriene B4 (LTB4). We sought to determine whether this two-step eicosanoid chemoattractant mechanism could be exploited by the pathogen Pseudomonas aeruginosa. ExoU, a P. aeruginosa cytotoxin, exhibits phospholipase A2 (PLA2) activity in eukaryotic hosts, an enzyme critical for generation of certain eicosanoids. Using in vitro and in vivo models of neutrophil transepithelial migration, we evaluated the impact of ExoU expression on eicosanoid generation and function. We conclude that ExoU, by virtue of its PLA2 activity, augments and compensates for endogenous host neutrophil cPLA2α function, leading to enhanced transepithelial migration. This suggests that ExoU expression in P. aeruginosa can circumvent immune regulation at key signaling checkpoints in the neutrophil, resulting in exacerbated neutrophil recruitment.

Pseudomonas aeruginosa ExoU augments neutrophil transepithelial migration.

Directory of Open Access Journals (Sweden)

Michael A Pazos

2017-08-01

Full Text Available Excessive neutrophil infiltration of the lungs is a common contributor to immune-related pathology in many pulmonary disease states. In response to pathogenic infection, airway epithelial cells produce hepoxilin A3 (HXA3, initiating neutrophil transepithelial migration. Migrated neutrophils amplify this recruitment by producing a secondary gradient of leukotriene B4 (LTB4. We sought to determine whether this two-step eicosanoid chemoattractant mechanism could be exploited by the pathogen Pseudomonas aeruginosa. ExoU, a P. aeruginosa cytotoxin, exhibits phospholipase A2 (PLA2 activity in eukaryotic hosts, an enzyme critical for generation of certain eicosanoids. Using in vitro and in vivo models of neutrophil transepithelial migration, we evaluated the impact of ExoU expression on eicosanoid generation and function. We conclude that ExoU, by virtue of its PLA2 activity, augments and compensates for endogenous host neutrophil cPLA2α function, leading to enhanced transepithelial migration. This suggests that ExoU expression in P. aeruginosa can circumvent immune regulation at key signaling checkpoints in the neutrophil, resulting in exacerbated neutrophil recruitment.

Gentamicin in Pseudomonas aeruginosa

African Journals Online (AJOL)

infections by Ps. aeruginosa is contra-indicated. In our study only 2,3 % of the Ps. aeruginosa strains were resistant to gentamicin (MIC 25 Ilg/ml). In view of the synergy reported for combined gentamicin and carbeni- cillin therapy," a combination of these two drugs may be recommended in the treatment of all Pseudomonas.

Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

DEFF Research Database (Denmark)

Johansen, Helle Krogh; Gøtzsche, Peter C

2013-01-01

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

Sensitivity patterns of pseudomonas aeruginosa isolates obtained from clinical specimens in peshawar

International Nuclear Information System (INIS)

Abbas, S.H.; Khan, M.Z.U.; Naeem, M.

2015-01-01

Pseudomonas aeruginosa (P. aeruginosa) is a highly virulent opportunistic pathogen and a leading cause of nosocomial infections.Affected patients are often hospitalized in an intensive care unit, and are immuno-compromised as a result of disease and treatment. Suspected P. aeruginosa require timely, adequate and empirical antibiotic therapy to ensure improved outcomes. The purpose of the study was to find the sensitivity and resistance pattern of P. aeruginosa to various groups of drugs, in clinical isolates collected from two major tertiary care hospitals of Peshawar. Methods: Different clinical isolate were taken from patients admitted in various wards of Khyber Teaching Hospital and Lady Reading Hospital Peshawar. Results: A total of 258 clinical isolates were positive for P. aeruginosa out of 2058 clinical isolates. Pseudomonas showed high degree of resistance to third generation Cephalosporins (Ceftazidime, and Ceftriaxone) and moderate degree of resistance to Quinolones and Aminoglycosides (Ofloxacin, Ciprofloxacin, Levofloxacin and Amikacin). Low resistance was observed to different combinations (Cefoperazone + Sulbactum, Piperacillin + Tazobactum). Meropenem and Imipenem had negligible resistance. Conclusion: There is growing resistance to different classes of antibiotics. Combination drugs are useful approach for empirical treatment in suspected Pseudomonas infection. Imipenem and Meropenem are extremely effective but should be in reserve. (author)

Mechanisms involved in the evasion of the host defence by Pseudomonas aeruginosa

DEFF Research Database (Denmark)

Kharazmi, A

1991-01-01

Pseudomonas aeruginosa, an extracellular opportunistic pathogen, utilizes two major mechanisms to evade the host defence system. One of these mechanisms is the production of a large number of extracellular products, such as proteases, toxins, and lipases. The two proteases, alkaline protease and ...

Experimental Pseudomonas aeruginosa mediated rhino sinusitis in mink

DEFF Research Database (Denmark)

Kirkeby, S.; Hammer, A. S.; Høiby, N.

2017-01-01

The nasal and sinus cavities in children may serve as reservoirs for microorganisms that cause recurrent and chronic lung infections. This study evaluates whether the mink can be used as an animal model for studying Pseudomonas aeruginosa mediated rhino-sinusitis since there is no suitable...... in the infected mink shows features of carbohydrate expression comparable to what has been described in the respiratory system after Pseudomonas aeruginosa infection in humans. It is suggested that the mink is suitable for studying Pseudomonas aeruginosa mediated rhino-sinusitis....

Pseudomonas aeruginosa elastase cleaves a C-terminal peptide from human thrombin that inhibits host inflammatory responses

DEFF Research Database (Denmark)

van der Plas, Mariena J A; Bhongir, Ravi K V; Kjellström, Sven

2016-01-01

Pseudomonas aeruginosa is an opportunistic pathogen known for its immune evasive abilities amongst others by degradation of a large variety of host proteins. Here we show that digestion of thrombin by P. aeruginosa elastase leads to the release of the C-terminal thrombin-derived peptide FYT21...

Respiratory syncytial virus infection facilitates acute colonization of Pseudomonas aeruginosa in mice

DEFF Research Database (Denmark)

de Vrankrijker, Angélica M M; Wolfs, Tom F W; Ciofu, Oana

2009-01-01

virus infections in facilitating colonization and infection with P. aeruginosa. A study was undertaken to determine whether respiratory syncytial virus (RSV) infection could facilitate the initiation of an acute infection with P. aeruginosa in vivo. Balb/c mice were infected intranasally with P......Pseudomonas aeruginosa causes opportunistic infections in immunocompromised individuals and patients ventilated mechanically and is the major pathogen in patients with cystic fibrosis, in which it causes chronic infections. Epidemiological, in vitro and animal data suggest a role for respiratory....... These results suggest that RSV can facilitate the initiation of acute P. aeruginosa infection without the RSV infection being clinically apparent. This could have implications for treatment strategies to prevent opportunistic P. aeruginosa lung infection....

Targeting quorum sensing in Pseudomonas aeruginosa biofilms

DEFF Research Database (Denmark)

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

2013-01-01

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

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

DEFF Research Database (Denmark)

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

2007-01-01

The ability to establish lifelong persistent infections is a fundamental aspect of the interactions between many pathogenic microorganisms and their mammalian hosts. One example is chronic lung infections by the opportunistic pathogen Pseudomonas aeruginosa in cystic fibrosis (CF) patients....... This infection process is associated with extensive genetic adaptation and microevolution of the infecting bacteria. Through investigations of P. aeruginosa populations and infection dynamics in a group of CF patients followed at the Danish CF Clinic in Copenhagen, we have identified two distinct and dominant...

Genome Sequence of Pseudomonas aeruginosa Strain DK1-NH57388A, a Stable Mucoid Cystic Fibrosis Isolate

DEFF Research Database (Denmark)

Norman, Anders; Ciofu, Oana; Amador Hierro, Cristina Isabel

2016-01-01

Pseudomonas aeruginosa is an important opportunistic pathogen associated with chronic pulmonary infections and mortality in cystic fibrosis (CF) patients. Here, we present the complete genome sequence of stable mucoid P. aeruginosa strain DK1-NH57388A, a CF isolate which has previously been used...

Novel Targets for Treatment of Pseudomonas aeruginosa Biofilms

DEFF Research Database (Denmark)

Alhede, Morten; Alhede, Maria; Bjarnsholt, Thomas

2014-01-01

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

Inhibition of Pseudomonas aeruginosa elastase and Pseudomonas keratitis using a thiol-based peptide.

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Burns, F R; Paterson, C A; Gray, R D; Wells, J T

1990-01-01

Pseudomonas aeruginosa elastase is a zinc metalloproteinase which is released during P. aeruginosa infections. Pseudomonas keratitis, which occurs following contact lens-induced corneal trauma, can lead to rapid, liquefactive necrosis of the cornea. This destruction has been attributed to the release of both host-derived enzymes and the bacterial products P. aeruginosa elastase, alkaline protease, exotoxin A, and lipopolysaccharide endotoxin. A synthetic metalloproteinase inhibitor, HSCH2 (DL...

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

DEFF Research Database (Denmark)

Qin, Zhiqiang; Yang, Liang; Qu, Di

2009-01-01

Multiple bacterial species often coexist as communities, and compete for environmental resources. Here, we describe how an opportunistic pathogen, Pseudomonas aeruginosa, uses extracellular products to interact with the nosocomial pathogen Staphylococcus epidermidis. S. epidermidis biofilms and p...... of a novel strategy for controlling S. epidermidis biofilms....

Prevalence and analysis of Pseudomonas aeruginosa in chinchillas

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Aoyama Naoki

2010-11-01

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

Disulfide Bond-Containing Ajoene Analogues As Novel Quorum Sensing Inhibitors of Pseudomonas aeruginosa

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Fong, July; Yuan, Mingjun; Jakobsen, Tim Holm

2017-01-01

Since its discovery 22 years ago, the bacterial cell-to-cell communication system, termed quorum sensing (QS), has shown potential as antipathogenic target. Previous studies reported that ajoene from garlic inhibits QS in opportunistic human pathogen Pseudomonas aeruginosa. In this study, screening...

Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

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

2008-01-01

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

Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

DEFF Research Database (Denmark)

Johansen, Helle Krogh; Gøtzsche, Peter C

2015-01-01

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

Multiple sensors control reciprocal expression of Pseudomonas aeruginosa regulatory RNA and virulence genes

DEFF Research Database (Denmark)

Ventre, I.; Goodman, A.L.; Vallet-Gely, I.

2006-01-01

The opportunistic pathogen Pseudomonas aeruginosa is responsible for a wide range of acute and chronic infections. The transition to chronic infections is accompanied by physiological changes in the bacteria favoring formation of biofilm communities. Here we report the identification of LadS, a h...

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

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

2006-09-20

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

Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation

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

2014-01-01

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

Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation

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Garry Laverty

2014-07-01

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

RESEARCH IN SENSITIVITY TO ANTIBIOTICS, ANTISEPTICS IN PSEUDOMONAS AERUGINOSA STRAINS ISOLATED FROM PATIENTS WITH INFECTIOUS COMPLICATIONS

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O. A. Nazarchuk

2017-07-01

Full Text Available Background. Infections caused by Pseudomonas are one of the topical issues of medicine. Objective. The aim of the research was to study sensityvity to antibiotics, antiseptics of P. aeruginosa clinical strains that cause infectious complications in patients with burns. Methods. Microbiological study of biological material, received from 435 patients with burns of the 3rd-4th stages (2011-2015 years. In early terms of burn disease 127 clinical strains of P. aeruginosa were isolated from patients. Standard methods were used to identify clinical isolates of P. aeruginosa by their morphological, tinctirial, culture and biochemical properties. The research of antimicrobial action of antiseptics, antibiotics against Pseudomonas were carried out by means of standard methods according to the Directive of the Ministry of Health of Ukraine (No. 167 from 05.04.2007 р. and guidelines of National Committee of Clinical and Laboratory Study (NCCLS, 2002. Results. It was established that P. aeruginosa caused infectious complications in 23.9% of patients among other pathogens. Clinical isolates of P. aeruginosa were found to be low sensitive to amoxicillin/clavulanate (30.76%, ceftazidime (25.92%, cefoperazonum/sulbactam (46.15%, aztreonam (51.85%, tobramycin (38.46%, amicacin (70.34%, doxiciclini (26.92%, fluoroquinolones (59.26%. The analitical progistic criteria of decrease of sensitivity to ceftazidime, cefepim, meropenem and gatifloxacin were found in P. aeruginosa. This pathogen was determined to be sensitive to decasan ®, antimicrobial composition of decamethoxine ®, iodine pvidone. Conclusions. Clinical strains of Pseudomonas aeruginosa, being highly resistant to antibiotics, are also very sensitive to antiseptics decasan ®, antimicrobial of decamethoxine®, povidone iodine.

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

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Bjarnsholt, Thomas; Jensen, P. Ø.; Rasmussen, Thomas Bovbjerg

2005-01-01

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

Evolution of Transcriptional Regulatory Networks in Pseudomonas aeruginosa During Long Time Growth in Human Hosts

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Andresen, Eva Kammer

extent these observations relate to natural microbial populations. The focus of this thesis has been to study how regulatory networks evolve in natural systems. By using a particular infectious disease scenario (human associated persistent airway infections caused by the bacterium Pseudomonas aeruginosa...... in global regulator genes facilitate the generation of novel phenotypes which again facilitate the shift in life-style of the bacterium from an environmental opportunistic pathogen to a human airway specific pathogen. These findings are not only applicable to P. aeruginosa specific studies, but suggest that...

Pseudomonas aeruginosa host-adaptation in cystic fibrosis patients

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Rau, Martin Holm

Pseudomonas aeruginosa is an opportunistic pathogen capable of transition from an environmental lifestyle to a host-associated lifestyle, as exemplified in the life-long airway infection of cystic fibrosis (CF) patients. Long-term infection is associated with extensive genetic adaptation of P...... the framework upon which this thesis is based. Early P. aeruginosa colonization of the CF airways is the period in which the outcome of infection is determined, i.e. if the bacteria are eventually eradicated or persist. In three patient cases the evolutionary events from initiation of infection were explored...... to unravel the early adaptive processes possibly securing bacterial persistence. In this early stage, clinical isolates displayed few adaptive events however these included phenotypes often observed in late chronic infection isolates including the conversion to a mucoid phenotype and increased antibiotic...

Pseudomonas aeruginosa uses T3SS to inhibit diabetic wound healing.

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

2015-01-01

Diabetic foot ulcers are responsible for more hospitalizations than any other complication of diabetes. Bacterial infection is recognized as an important factor associated with impaired healing in diabetic ulcers. Pseudomonas aeruginosa is the most frequently detected Gram-negative pathogen in diabetic ulcers. P. aeruginosa infection has been shown to impair healing in diabetic wounds in a manner that correlates with its ability to form biofilm. While the majority of infections in diabetic ulcers are biofilm associated, 33% of infections are nonbiofilm in nature. P. aeruginosa is the most prevalent Gram-negative pathogen in all diabetic wound types, which suggests that the deleterious impact of P. aeruginosa on healing in diabetic wounds goes beyond its ability to form biofilm and likely involves other factors. The Type III Secretion System (T3SS) virulence structure is required for the pathogenesis of all P. aeruginosa clinical isolates, suggesting that it may also play a role in the inhibition of wound repair in diabetic skin ulcers. We evaluated the role of T3SS in mediating P. aeruginosa-induced tissue damage in the wounds of diabetic mice. Our data demonstrate that P. aeruginosa establishes a robust and persistent infection in diabetic wounds independent of its ability to form biofilm and causes severe wound damage in a manner that primarily depends on its T3SS. © 2015 by the Wound Healing Society.

Effect of Garlic Oil on Attenuation of Pseudomonas aeruginosa Infection Induced in Mice

International Nuclear Information System (INIS)

Eltablawy, S.Y.; Elhifnawi, H.N.

2010-01-01

The antimicrobial activity and other medical benefits of garlic oil have been attributed to the presence of sulphides in it. Pseudomonas aeruginosa is a multidrug resistance opportunistic human pathogen that infect many patients .To control these infections, there is a need for other agents with greater antimicrobial activity and less toxicity. In this study, the effect of irradiated and non-irradiated garlic oil has been evaluated. The irradiation of garlic oil at 10.0 kGy decreased slightly its antibacterial activity against the tested Pseudomonas aeruginosa. The results revealed that there was no effect of garlic oil either irradiated or non-irradiated on the adherent cells formed by Pseudomonas aeruginosa tested organism on tissue culture plate. Garlic oil (irradiated or nonirradiated) was administrated subcutaneously as treatment for a mouse infection model. Bacteriological examination and mortality rate were used as indicators. The treatment with non-irradiated garlic oil decreased the number of bacteria in the infected group in contrast with the placebo group (saline), while, irradiation of garlic oil with 10.0 kGy had no effect on the infected bacteria. Also, the results indicated that, the treatment with non-irradiated garlic oil decreased the mortality in comparison with irradiated garlic oil which did not show any effect. Scanning electron microscopy study revealed that there were morphological changes in the Pseudomonas aeruginosa treated with non- irradiated garlic oil in comparison with untreated one

Genome Sequence of Pseudomonas aeruginosa Strain DK1-NH57388A, a Stable Mucoid Cystic Fibrosis Isolate

DEFF Research Database (Denmark)

Norman, Anders; Ciofu, Oana; Amador Hierro, Cristina Isabel

2016-01-01

Pseudomonas aeruginosa is an important opportunistic pathogen associated with chronic pulmonary infections and mortality in cystic fibrosis (CF) patients. Here, we present the complete genome sequence of stable mucoid P. aeruginosa strain DK1-NH57388A, a CF isolate which has previously been used ...

Enzyme-mediated quenching of the Pseudomonas quinolone signal (PQS promotes biofilm formation of Pseudomonas aeruginosa by increasing iron availability

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Beatrix Tettmann

2016-12-01

Full Text Available The 2-alkyl-3-hydroxy-4(1H-quinolone 2,4-dioxygenase HodC was previously described to cleave the Pseudomonas quinolone signal, PQS, which is exclusively used in the complex quorum sensing (QS system of Pseudomonas aeruginosa, an opportunistic pathogen employing QS to regulate virulence and biofilm development. Degradation of PQS by exogenous addition of HodC to planktonic cells of P. aeruginosa attenuated production of virulence factors, and reduced virulence in planta. However, proteolytic cleavage reduced the efficacy of HodC. Here, we identified the secreted protease LasB of P. aeruginosa to be responsible for HodC degradation. In static biofilms of the P. aeruginosa PA14 lasB::Tn mutant, the catalytic activity of HodC led to an increase in viable biomass in newly formed but also in established biofilms, and reduced the expression of genes involved in iron metabolism and siderophore production, such as pvdS, pvdL, pvdA and pvdQ. This is likely due to an increase in the levels of bioavailable iron by degradation of PQS, which is able to sequester iron from the surrounding environment. Thus, HodC, despite its ability to quench the production of virulence factors, is contraindicated for combating P. aeruginosa biofilms.

Crystal structure of secretory protein Hcp3 from Pseudomonas aeruginosa

OpenAIRE

Osipiuk, Jerzy; Xu, Xiaohui; Cui, Hong; Savchenko, Alexei; Edwards, Aled; Joachimiak, Andrzej

2011-01-01

The Type VI secretion pathway transports proteins across the cell envelope of Gram-negative bacteria. Pseudomonas aeruginosa, an opportunistic Gram-negative bacterial pathogen infecting humans, uses the type VI secretion pathway to export specific effector proteins crucial for its pathogenesis. The HSI-I virulence locus encodes for several proteins that has been proposed to participate in protein transport including the Hcp1 protein, which forms hexameric rings that assemble into nanotubes in...

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

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

2016-04-15

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

A Pseudomonas aeruginosa toxin that hijacks the host ubiquitin proteolytic system.

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Jennifer M Bomberger

2011-03-01

Full Text Available Pseudomonas aeruginosa (P. aeruginosa is an opportunistic pathogen chronically infecting the lungs of patients with chronic obstructive pulmonary disease (COPD, pneumonia, cystic fibrosis (CF, and bronchiectasis. Cif (PA2934, a bacterial toxin secreted in outer membrane vesicles (OMV by P. aeruginosa, reduces CFTR-mediated chloride secretion by human airway epithelial cells, a key driving force for mucociliary clearance. The aim of this study was to investigate the mechanism whereby Cif reduces CFTR-mediated chloride secretion. Cif redirected endocytosed CFTR from recycling endosomes to lysosomes by stabilizing an inhibitory effect of G3BP1 on the deubiquitinating enzyme (DUB, USP10, thereby reducing USP10-mediated deubiquitination of CFTR and increasing the degradation of CFTR in lysosomes. This is the first example of a bacterial toxin that regulates the activity of a host DUB. These data suggest that the ability of P. aeruginosa to chronically infect the lungs of patients with COPD, pneumonia, CF, and bronchiectasis is due in part to the secretion of OMV containing Cif, which inhibits CFTR-mediated chloride secretion and thereby reduces the mucociliary clearance of pathogens.

Staphylococcus aureus Alters Growth Activity, Autolysis, and Antibiotic Tolerance in a Human Host-Adapted Pseudomonas aeruginosa Lineage

DEFF Research Database (Denmark)

Frydenlund Michelsen, Charlotte; Christensen, Anne-Mette; Bojer, Martin Saxtorph

2014-01-01

Interactions among members of polymicrobial infections or between pathogens and the commensal flora may determine disease outcomes. Pseudomonas aeruginosa and Staphylococcus aureus are important opportunistic human pathogens and are both part of the polymicrobial infection communities in human...... hosts. In this study, we analyzed the in vitro interaction between S. aureus and a collection of P. aeruginosa isolates representing different evolutionary steps of a dominant lineage, DK2, that have evolved through decades of growth in chronically infected patients. While the early adapted P....... aeruginosa DK2 strains outcompeted S. aureus during coculture on agar plates, we found that later P. aeruginosa DK2 strains showed a commensal-like interaction, where S. aureus was not inhibited by P. aeruginosa and the growth activity of P. aeruginosa was enhanced in the presence of S. aureus. This effect...

What It Takes to Be a Pseudomonas aeruginosa? The Core Genome of the Opportunistic Pathogen Updated.

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Benoît Valot

Full Text Available Pseudomonas aeruginosa is an opportunistic bacterial pathogen able to thrive in highly diverse ecological niches and to infect compromised patients. Its genome exhibits a mosaic structure composed of a core genome into which accessory genes are inserted en bloc at specific sites. The size and the content of the core genome are open for debate as their estimation depends on the set of genomes considered and the pipeline of gene detection and clustering. Here, we redefined the size and the content of the core genome of P. aeruginosa from fully re-analyzed genomes of 17 reference strains. After the optimization of gene detection and clustering parameters, the core genome was defined at 5,233 orthologs, which represented ~ 88% of the average genome. Extrapolation indicated that our panel was suitable to estimate the core genome that will remain constant even if new genomes are added. The core genome contained resistance determinants to the major antibiotic families as well as most metabolic, respiratory, and virulence genes. Although some virulence genes were accessory, they often related to conserved biological functions. Long-standing prophage elements were subjected to a genetic drift to eventually display a G+C content as higher as that of the core genome. This contrasts with the low G+C content of highly conserved ribosomal genes. The conservation of metabolic and respiratory genes could guarantee the ability of the species to thrive on a variety of carbon sources for energy in aerobiosis and anaerobiosis. Virtually all the strains, of environmental or clinical origin, have the complete toolkit to become resistant to the major antipseudomonal compounds and possess basic pathogenic mechanisms to infect humans. The knowledge of the genes shared by the majority of the P. aeruginosa isolates is a prerequisite for designing effective therapeutics to combat the wide variety of human infections.

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

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S. Mustafi

2015-01-01

Full Text Available 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.

Chemical Modification and Detoxification of the Pseudomonas aeruginosa Toxin 2-Heptyl-4-hydroxyquinoline N-Oxide by Environmental and Pathogenic Bacteria.

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Thierbach, Sven; Birmes, Franziska S; Letzel, Matthias C; Hennecke, Ulrich; Fetzner, Susanne

2017-09-15

2-Heptyl-4-hydroxyquinoline N-oxide (HQNO), a major secondary metabolite and virulence factor produced by the opportunistic pathogen Pseudomonas aeruginosa, acts as a potent inhibitor of respiratory electron transfer and thereby affects host cells as well as microorganisms. In this study, we demonstrate the previously unknown capability of environmental and pathogenic bacteria to transform and detoxify this compound. Strains of Arthrobacter and Rhodococcus spp. as well as Staphylococcus aureus introduced a hydroxyl group at C-3 of HQNO, whereas Mycobacterium abscessus, M. fortuitum, and M. smegmatis performed an O-methylation, forming 2-heptyl-1-methoxy-4-oxoquinoline as the initial metabolite. Bacillus spp. produced the glycosylated derivative 2-heptyl-1-(β-d-glucopyranosydyl)-4-oxoquinoline. Assaying the effects of these metabolites on cellular respiration and on quinol oxidase activity of membrane fractions revealed that their EC 50 values were up to 2 orders of magnitude higher than that of HQNO. Furthermore, cellular levels of reactive oxygen species were significantly lower in the presence of the metabolites than under the influence of HQNO. Therefore, the capacity to transform HQNO should lead to a competitive advantage against P. aeruginosa. Our findings contribute new insight into the metabolic diversity of bacteria and add another layer of complexity to the metabolic interactions which likely contribute to shaping polymicrobial communities comprising P. aeruginosa.

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

DEFF Research Database (Denmark)

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

2016-01-01

Drug resistance and tolerance greatly diminish the therapeutic potential of antibiotics against pathogens. Antibiotic tolerance by bacterial biofilms often leads to persistent infections, but its mechanisms are unclear. Here we use a proteomics approach, pulsed stable isotope labelling with amino...... acids (pulsed-SILAC), to quantify newly expressed proteins in colistin-tolerant subpopulations of Pseudomonas aeruginosa biofilms (colistin is a 'last-resort' antibiotic against multidrug-resistant Gram-negative pathogens). Migration is essential for the formation of colistin-tolerant biofilm...

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

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

2013-04-17

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

Detection of bla-IMP-1 and bla-IMP-2 Genes Among Metallo-β-lactamase-Producing Pseudomonas Aeruginosa Isolated from Burn Patients in Isfahan

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M. Pourbabaee

2016-02-01

Full Text Available Background: Pseudomonas aeruginosa is a nosocomial pathogen which especially causes infections among burn patients. Carbapenems are extensively used for the treatment of infections caused by multidrug-resistant P. aeruginosa isolates. The emergence of carbapenemases producing isolates is an outcome of increased utilization of carbapenems. The aim of this study was to determine the bla-IMP-1 and bla-IMP-2 genes in metallo-β-lactamase (MBL -producing Pseudomonas aeruginosa isolated from burn patients in Isfahan. Material and Methods: A total of 150 P. aeruginosa were isolated from burn patients hospitalized in Imam-Mousakazem hospital in Isfahan. Antimicrobial susceptibility was determined using disk diffusion method according to the Clinical and Laboratory Standards Institute (CLSI guidelines. Double Disk Synergy Test (DDST was carried out for screening of MBL production in imipenem-resistant strains. PCR assays were used for detection of bla-IMP-1 and bla-IMP-2 genes among metallo-β-lactamase-producing Pseudomonas aeruginosa isolates. The purified PCR products were sequenced. Results: Of 150 Pseudomonas aeruginosa isolates, %100 identified as multi-drug resistant strains. The most resistance rates were seen against ciprofloxacin, tobromycin, meropenem and imipenem. All of 144 imipenem-resistant Pseudomonas aeruginosa isolates were MBL producing by DDST test. Twenty-nine (19.3% and 8(5.3% MBL producing Pseudomonas aeruginosa isolates harbored bla-IMP-1 and bla-IMP-2 genes respectively. Conclusions: According to results of this study high level resistance to imipenem and MBl genes carriage was seen among Pseudomonas aeruginosa isolated from burn patient infections in our region.

Anti-Pseudomonas aeruginosa IgY antibodies augment bacterial clearance in a murine pneumonia model

DEFF Research Database (Denmark)

Thomsen, K.; Christophersen, L.; Bjarnsholt, T.

2016-01-01

Background: Oral prophylactic therapy by gargling with pathogen-specific egg yolk immunoglobulins (IgY) may reduce the initial airway colonization with Pseudomonas aeruginosa in cystic fibrosis (CF) patients. IgY antibodies impart passive immunization and we investigated the effects of anti......-P. aeruginosa IgY antibodies on bacterial eradication in a murine pneumonia model. Methods: P. aeruginosa pneumonia was established in Balb/c mice and the effects of prophylactic IgY administration on lung bacteriology, clinical parameters and subsequent inflammation were compared to controls. Results......: Prophylactic administration of IgY antibodies targeting P. aeruginosa significantly reduced the bacterial burden by 2-log 24 h post-infection compared to controls and was accompanied by significantly reduced clinical symptom scores and successive inflammatory cytokine profile indicative of diminished lung...

Ultraviolet-B lethal damage on Pseudomonas aeruginosa

International Nuclear Information System (INIS)

Degiorgi, C.F.; Fernandez, R.O.; Pizarro, R.A.

1996-01-01

Pseudomonas aeruginosa has shown an increased sensitivity compared with that of Escherichia coli and Enterobacter cloacae, when they were exposed to 0.4 kJ/m2 of ultraviolet-B radiation. The rapid decay in cell viability observed in Pseudomonas aeruginosa after the irradiation was influenced by factors such as culture media and the presence of pyocyanine during the irradiation. The radioinduced lethal damage could be prevented by photoreactivating treatment, indicating that pyrimidine dimer formation was the mechanism causing bacterial death. The results indicate that several environmental conditions may act as protective agents against ultraviolet-B-induced damage

Antibiotics Susceptibility Pattern of Pseudomonas aeruginosa ...

African Journals Online (AJOL)

ABSTRACT: This work investigated the prevalence and antibiotics sensitivity of Pseudomonas aeruginosa isolated from ... skin triggers coagulation and an acute inflammatory response ... agents with anti-pseudomonal activity, life-threatening.

[The effect of biyuanshu oral liquid on the formation of Pseudomonas aeruginosa biofilms in vitro].

Science.gov (United States)

Liu, Xiang; Chen, Haihong; Wang, Shengqing

2012-07-01

To observe the effect of biyuanshu oral liquid on the formation of pseudomonas aeruginosa biofilms in vitro. Pseudomonas aeruginosa biofilm was established by plate culture and detected by Scanning electron microscopy and AgNO3 staining. After treated with different dosages of biyuanshu oral liquid and erythromycin, the pseudomonas aeruginosa biofilms were observed by AgNO3 staining and the number of viable bacteria were measured by serial dilution. The pseudomonas aeruginosa biofilms could be detected by SEM at the seventh culture day and it was consistent with the detection of AgNO3 staining. The biyuanshu oral liquid and erythromycin have the effect on inhibiting the formation of pseudomonas aeruginosa biofilms. But with the already formed pseudomonas aeruginosa biofilms the inhibition was not significant. The serial dilution method showed that the viable counts of bacteria of biyuanshu oral liquid and erythromycin treated groups were significantly lower than those untreated groups (P formation of pseudomonas aeruginosa biofilms in vitro.

Crystal structure of secretory protein Hcp3 from Pseudomonas aeruginosa.

Science.gov (United States)

Osipiuk, Jerzy; Xu, Xiaohui; Cui, Hong; Savchenko, Alexei; Edwards, Aled; Joachimiak, Andrzej

2011-03-01

The Type VI secretion pathway transports proteins across the cell envelope of Gram-negative bacteria. Pseudomonas aeruginosa, an opportunistic Gram-negative bacterial pathogen infecting humans, uses the type VI secretion pathway to export specific effector proteins crucial for its pathogenesis. The HSI-I virulence locus encodes for several proteins that has been proposed to participate in protein transport including the Hcp1 protein, which forms hexameric rings that assemble into nanotubes in vitro. Two Hcp1 paralogues have been identified in the P. aeruginosa genome, Hsp2 and Hcp3. Here, we present the structure of the Hcp3 protein from P. aeruginosa. The overall structure of the monomer resembles Hcp1 despite the lack of amino-acid sequence similarity between the two proteins. The monomers assemble into hexamers similar to Hcp1. However, instead of forming nanotubes in head-to-tail mode like Hcp1, Hcp3 stacks its rings in head-to-head mode forming double-ring structures.

Identification of small molecule inhibitors of Pseudomonas aeruginosa exoenzyme S using a yeast phenotypic screen.

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Anthony Arnoldo

2008-02-01

Full Text Available Pseudomonas aeruginosa is an opportunistic human pathogen that is a key factor in the mortality of cystic fibrosis patients, and infection represents an increased threat for human health worldwide. Because resistance of Pseudomonas aeruginosa to antibiotics is increasing, new inhibitors of pharmacologically validated targets of this bacterium are needed. Here we demonstrate that a cell-based yeast phenotypic assay, combined with a large-scale inhibitor screen, identified small molecule inhibitors that can suppress the toxicity caused by heterologous expression of selected Pseudomonas aeruginosa ORFs. We identified the first small molecule inhibitor of Exoenzyme S (ExoS, a toxin involved in Type III secretion. We show that this inhibitor, exosin, modulates ExoS ADP-ribosyltransferase activity in vitro, suggesting the inhibition is direct. Moreover, exosin and two of its analogues display a significant protective effect against Pseudomonas infection in vivo. Furthermore, because the assay was performed in yeast, we were able to demonstrate that several yeast homologues of the known human ExoS targets are likely ADP-ribosylated by the toxin. For example, using an in vitro enzymatic assay, we demonstrate that yeast Ras2p is directly modified by ExoS. Lastly, by surveying a collection of yeast deletion mutants, we identified Bmh1p, a yeast homologue of the human FAS, as an ExoS cofactor, revealing that portions of the bacterial toxin mode of action are conserved from yeast to human. Taken together, our integrated cell-based, chemical-genetic approach demonstrates that such screens can augment traditional drug screening approaches and facilitate the discovery of new compounds against a broad range of human pathogens.

Pseudomonas aeruginosa, an emerging pathogen among burn patients in Kurdistan Province, Iran.

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Kalantar, Enayat; Taherzadeh, Shadi; Ghadimi, Tayeb; Soheili, Fariborz; Salimizand, Heiman; Hedayatnejad, Alireza

2012-05-01

This study was conducted to determine the incidence of Pseudomonas aeruginosa infections among burn patients at Tohid Hospital, Iran. A total of 176 clinical specimens were obtained from 145 burn patients admitted to the burn unit of Tohid Hospital to detect the presence of P. aeruginosa. Antimicrobial susceptibility testing was conducted to detect extended spectrum beta-lactamase (ESBL) producing P. aeruginiosa using Clinical and Laboratory Standards Institute guidelines with the double disc synergy test (DDST). A polymerase chain reaction was used to detect PER-1 and OXA-10 among the isolates. The mean age, total body surface area and length of hospital stay among patients were 29 years, 37.7%, and 10 days, respectively. Kerosene was the commonest cause of burn (60%), followed by gas (30%). During the study, P. aeruginosa was detected in 100 isolates. The antibiotics they were most commonly resistant to were cefotaxime, ceftriaxone and ciprofloxacin. Of the 100 P. aeroginusa isolates, 28% were positive for ESBL production with the DDST, 48% and 52% were PER-1 and OXA-10 producers, respectively. The high frequency of PER-1 and OXA-10 producers at this hospital is of concern considering their potential spread among burn patients.

Plant-expressed pyocins for control of Pseudomonas aeruginosa.

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Šarūnas Paškevičius

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

Mechanistic Insights into Elastin Degradation by Pseudolysin, the Major Virulence Factor of the Opportunistic Pathogen Pseudomonas aeruginosa

Science.gov (United States)

Yang, Jie; Zhao, Hui-Lin; Ran, Li-Yuan; Li, Chun-Yang; Zhang, Xi-Ying; Su, Hai-Nan; Shi, Mei; Zhou, Bai-Cheng; Chen, Xiu-Lan; Zhang, Yu-Zhong

2015-01-01

Pseudolysin is the most abundant protease secreted by Pseudomonas aeruginosa and is the major extracellular virulence factor of this opportunistic human pathogen. Pseudolysin destroys human tissues by solubilizing elastin. However, the mechanisms by which pseudolysin binds to and degrades elastin remain elusive. In this study, we investigated the mechanism of action of pseudolysin on elastin binding and degradation by biochemical assay, microscopy and site-directed mutagenesis. Pseudolysin bound to bovine elastin fibers and preferred to attack peptide bonds with hydrophobic residues at the P1 and P1’ positions in the hydrophobic domains of elastin. The time-course degradation processes of both bovine elastin fibers and cross-linked human tropoelastin by pseudolysin were further investigated by microscopy. Altogether, the results indicate that elastin degradation by pseudolysin began with the hydrophobic domains on the fiber surface, followed by the progressive disassembly of macroscopic elastin fibers into primary structural elements. Moreover, our site-directed mutational results indicate that five hydrophobic residues in the S1-S1’ sub-sites played key roles in the binding of pseudolysin to elastin. This study sheds lights on the pathogenesis of P. aeruginosa infection. PMID:25905792

Streptococcus pneumoniae and Pseudomonas aeruginosa pneumonia induce distinct host responses.

Science.gov (United States)

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

2010-01-01

Pathogens that cause pneumonia may be treated in a targeted fashion by antibiotics, but if this therapy fails, then treatment involves only nonspecific supportive measures, independent of the inciting infection. The purpose of this study was to determine whether host response is similar after disparate infections with similar mortalities. Prospective, randomized controlled study. Animal laboratory in a university medical center. Pneumonia was induced in FVB/N mice by either Streptococcus pneumoniae or two different concentrations of Pseudomonas aeruginosa. Plasma and bronchoalveolar lavage fluid from septic animals was assayed by a microarray immunoassay measuring 18 inflammatory mediators at multiple time points. The host response was dependent on the causative organism as well as kinetics of mortality, but the pro-inflammatory and anti-inflammatory responses were independent of inoculum concentration or degree of bacteremia. Pneumonia caused by different concentrations of the same bacteria, Pseudomonas aeruginosa, also yielded distinct inflammatory responses; however, inflammatory mediator expression did not directly track the severity of infection. For all infections, the host response was compartmentalized, with markedly different concentrations of inflammatory mediators in the systemic circulation and the lungs. Hierarchical clustering analysis resulted in the identification of five distinct clusters of the host response to bacterial infection. Principal components analysis correlated pulmonary macrophage inflammatory peptide-2 and interleukin-10 with progression of infection, whereas elevated plasma tumor necrosis factor sr2 and macrophage chemotactic peptide-1 were indicative of fulminant disease with >90% mortality within 48 hrs. Septic mice have distinct local and systemic responses to Streptococcus pneumoniae and Pseudomonas aeruginosa pneumonia. Targeting specific host inflammatory responses induced by distinct bacterial infections could represent a

Pseudomoniasis phytotherapy: a review on most important Iranian medicinal plants effective on Pseudomonas aeruginosa.

Science.gov (United States)

Bahmani, Mahmoud; Rafieian-Kopaei, Mahmoud; Hassanzadazar, Hassan; Taherikalani, Morovat

2016-10-01

Pseudomonas aeruginosa is a Gram-negative, aerobic bacterium found in water and soil. It is a normal flora in skin and gastrointestinal tract of human beings. P. aeruginosa as an opportunistic pathogen involved in nosocomial infections having multiple pathogenic factors and shows high rate of resistance to different antibiotics. The aim of this study was to identify the most important native medicinal plants of Iran effective on P. aeruginosa. All required information was obtained by searching keywords such as P. aeruginosa , medicinal plant extracts or essential oils in published articles in authentic scientific databases such as Science Direct, Wiley-Blackwell, Springer, Google scholar, Scientific Information Database (SID) and Magiran. According to the literature review, our results showed 12 different native medicinal plants were effective against P. aeruginosa in Iran including Eucalyptus camadulensis, Marticaria chamomilla, Ferula gummosa Boiss, Lawsonia inermis, Ocimumgra tissimum, Allium sativum, Satureja hortensis L, Satureja bachtiarica Bunge, Satureja khuzestanica (Jamzad), Thymus daenensis Celak, Thymus carmanicus Jalals and Camellia sinensis. Phytochemical analysis has shown that bioactive compounds of medicinal plants with their antioxidant and antimicrobial properties can be good alternatives for the synthetic medicines in food and drug industry.

Evaluation of Enoyl-Acyl Carrier Protein Reductase Inhibitors as Pseudomonas aeruginosa Quorum-Quenching Reagents

DEFF Research Database (Denmark)

Yang, Liang; Liu, Yang; Sternberg, Claus

2010-01-01

Pseudomonas aeruginosa is an opportunistic pathogen which is responsible for a wide range of infections. Production of virulence factors and biofilm formation by P. aeruginosa are partly regulated by cell-to-cell communication quorum-sensing systems. Identification of quorum-quenching reagents...... which block the quorum-sensing process can facilitate development of novel treatment strategies for P. aeruginosa infections. We have used molecular dynamics simulation and experimental studies to elucidate the efficiencies of two potential quorum-quenching reagents, triclosan and green tea...... epigallocatechin gallate (EGCG), which both function as inhibitors of the enoyl-acyl carrier protein (ACP) reductase (ENR) from the bacterial type II fatty acid synthesis pathway. Our studies suggest that EGCG has a higher binding affinity towards ENR of P. aeruginosa and is an efficient quorum-quenching reagent...

Pseudomonas aeruginosa burn wound infection in a dedicated ...

African Journals Online (AJOL)

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

Capsule production by Pseudomonas aeruginosa

Energy Technology Data Exchange (ETDEWEB)

Lynn, A.R.

1984-01-01

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

Genotypic and phenotypic analyses of a Pseudomonas aeruginosa chronic bronchiectasis isolate reveal differences from cystic fibrosis and laboratory strains

NARCIS (Netherlands)

Varga, J.J.; Barbier, Mariette; Mulet, Xavier; Bielecki, Piotr; Bartell, J.A.; Owings, J.P.; Martinez-Ramos, Inmaculada; Hittle, L.E.; Davis, M.R.; Damron, F.H.; Liechti, G.W.; Puchałka, Jacek; Martins dos Santos, Vitor; Ernst, R.K.; Papin, J.A.; Albertí, Sebastian; Oliver, Antonio; Goldberg, J.B.

2015-01-01

Background: Pseudomonas aeruginosa is an environmentally ubiquitous Gram-negative bacterium and important opportunistic human pathogen, causing severe chronic respiratory infections in patients with underlying conditions such as cystic fibrosis (CF) or bronchiectasis. In order to identify

A Carbenicillin R Factor from Pseudomonas aeruginosa | van ...

African Journals Online (AJOL)

Of 64 carbenicillin-resistant Pseudomonas aeruginosa strains 40 transferred this resistance to Escherichia coli. R factor RP-638 isolated from Ps. aeruginosa strain 638 conferred resistance to ampicillin, carbenicillin, kanamycin, neomycin and tetracycline. This R factor was transferred at frequencies 01 10-7 to 10-4 between ...

Discovery and biophysical characterization of 2-amino-oxadiazoles as novel antagonists of PqsR, an important regulator of Pseudomonas aeruginosa virulence.

Science.gov (United States)

Zender, Michael; Klein, Tobias; Henn, Claudia; Kirsch, Benjamin; Maurer, Christine K; Kail, Dagmar; Ritter, Christiane; Dolezal, Olan; Steinbach, Anke; Hartmann, Rolf W

2013-09-12

The human pathogen Pseudomonas aeruginosa employs alkyl quinolones for cell-to-cell communication. The Pseudomonas quinolone signal (PQS) regulates various virulence factors via interaction with the transcriptional regulator PqsR. Therefore, we consider the development of PqsR antagonists a novel strategy to limit the pathogenicity of P. aeruginosa. A fragment identification approach using surface plasmon resonance screening led to the discovery of chemically diverse PqsR ligands. The optimization of the most promising hit (5) resulted in the oxadiazole-2-amine 37 showing pure antagonistic activity in Escherichia coli (EC50 = 7.5 μM) and P. aeruginosa (EC50 = 38.5 μM) reporter gene assays. 37 was able to diminish the production of the PQS precursor HHQ in a PqsH-deficient P. aeruginosa mutant. The level of the major virulence factor pyocyanin was significantly reduced in wild-type P. aeruginosa. In addition, site-directed mutagenesis in combination with isothermal titration calorimetry and NMR INPHARMA experiments revealed that the identified ligands bind to the same site of PqsR by adopting different binding modes. These findings will be utilized in a future fragment-growing approach aiming at novel therapeutic options for the treatment of P. aeruginosa infections.

Pseudomonas aeruginosa (Family Pseudomonadaceae) is an ...

African Journals Online (AJOL)

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

Pseudomonas Aeruginosa: interactions with organisms in the environment and cells of the immune defence

DEFF Research Database (Denmark)

Skindersø, Mette Elena

2008-01-01

, which emphasises the urgent need for development of novel strategies that will help us to defeat this pathogen. P. aeruginosa biofilm cells display a multicellular-like coordinated behaviour and control expression of virulence factors, elements involved in biofilm development and immunomodulating...... factors by means of signal molecule mediated communication, known as quorum sensing. This thesis explores a strategy which aims to counteract P. aeruginosa virulence and pathogenicity by impeding its cell-to-cell communication. A treatment regime, which focuses on targeting bacterial communication instead......; two quorum sensing signal molecules; the Pseudomonas Quinolone Signal and N-3-oxododecanoyl L-homoserine lactone exhibit the ability to modulate activities of the immune defence in addition to functioning as quorum sensing mediators. The two signal molecules impair activities of immune cells crucial...

Comparative In Vitro Efficacy of Doripenem and Imipenem Against Multi-Drug Resistant Pseudomonas aeruginosa

International Nuclear Information System (INIS)

Wali, N.; Mirza, I. A.

2016-01-01

Objective: To compare the in vitro efficacy of doripenem and imipenem against multi-drug resistant (MDR) Pseudomonas aeruginosa from various clinical specimens. Study Design: Descriptive cross-sectional study. Place and Duration of Study: Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from November 2012 to November 2013. Methodology: MDR Pseudomonas aeruginosa isolates from various clinical samples were included in the study. Susceptibility of Pseudomonas aeruginosa against doripenem and imipenem was performed by E-test strip and agar dilution methods. The results were interpreted as recommended by Clinical Laboratory Standard Institute (CLSI) guidelines. Results: The maximum number of Pseudomonas aeruginosa were isolated from pure pus and pus swabs. In vitro efficacy of doripenem was found to be more effective as compared to imipenem against MDR Pseudomonas aeruginosa with both E-test strip and agar dilution methods. Overall, p-values of 0.014 and 0.037 were observed when susceptibility patterns of doripenem and imipenem were evaluated with E-test strip and agar dilution methods. Conclusion: In vitro efficacy of doripenem was found to be better against MDR Pseudomonas aeruginosa as compared to imipenem when tested by both E-test and agar dilution methods. (author)

Pseudomonas aeruginosa inhibits the growth of Cryptococcus species.

Science.gov (United States)

Rella, Antonella; Yang, Mo Wei; Gruber, Jordon; Montagna, Maria Teresa; Luberto, Chiara; Zhang, Yong-Mei; Del Poeta, Maurizio

2012-06-01

Pseudomonas aeruginosa is a ubiquitous and opportunistic bacterium that inhibits the growth of different microorganisms, including Gram-positive bacteria and fungi such as Candida spp. and Aspergillus fumigatus. In this study, we investigated the interaction between P. aeruginosa and Cryptococcus spp. We found that P. aeruginosa PA14 and, to a lesser extent, PAO1 significantly inhibited the growth of Cryptococcus spp. The inhibition of growth was observed on solid medium by the visualization of a zone of inhibition of yeast growth and in liquid culture by viable cell counting. Interestingly, such inhibition was only observed when P. aeruginosa and Cryptococcus were co-cultured. Minimal inhibition was observed when cell-cell contact was prevented using a separation membrane, suggesting that cell contact is required for inhibition. Using mutant strains of Pseudomonas quinoline signaling, we showed that P. aeruginosa inhibited the growth of Cryptococcus spp. by producing antifungal molecules pyocyanin, a redox-active phenazine, and 2-heptyl-3,4-dihydroxyquinoline (PQS), an extracellular quorum-sensing signal. Because both P. aeruginosa and Cryptococcus neoformans are commonly found in lung infections of immunocompromised patients, this study may have important implication for the interaction of these microbes in both an ecological and a clinical point of view.

Host translational inhibition by Pseudomonas aeruginosa Exotoxin A Triggers an immune response in Caenorhabditis elegans.

Science.gov (United States)

McEwan, Deborah L; Kirienko, Natalia V; Ausubel, Frederick M

2012-04-19

Intestinal epithelial cells are exposed to both innocuous and pathogenic microbes, which need to be distinguished to mount an effective immune response. To understand the mechanisms underlying pathogen recognition, we investigated how Pseudomonas aeruginosa triggers intestinal innate immunity in Caenorhabditis elegans, a process independent of Toll-like pattern recognition receptors. We show that the P. aeruginosa translational inhibitor Exotoxin A (ToxA), which ribosylates elongation factor 2 (EF2), upregulates a significant subset of genes normally induced by P. aeruginosa. Moreover, immune pathways involving the ATF-7 and ZIP-2 transcription factors, which protect C. elegans from P. aeruginosa, are required for preventing ToxA-mediated lethality. ToxA-responsive genes are not induced by enzymatically inactive ToxA protein but can be upregulated independently of ToxA by disruption of host protein translation. Thus, C. elegans has a surveillance mechanism to recognize ToxA through its effect on protein translation rather than by direct recognition of either ToxA or ribosylated EF2. Copyright © 2012 Elsevier Inc. All rights reserved.

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

DEFF Research Database (Denmark)

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

2014-01-01

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

Pseudomonas aeruginosa Psl Exopolysaccharide Interacts with the Antimicrobial Peptide LG21

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Joyce Seow Fong Chin

2017-09-01

Full Text Available Biofilm formation by opportunistic pathogens serves as one of the major causes of chronic and persistent infections. Bacterial cells in the biofilms are embedded in their self-generated protective extracellular polymeric substances (EPS, which include exopolysaccharides, large adhesin proteins and extracellular DNA. In this study, we identified an antimicrobial peptide (AMP LG21 that is able to interact specifically with the Psl exopolysaccharide of Pseudomonas aeruginosa, thus it can be used as a diagnostic tool for P. aeruginosa biofilms. Molecular dynamics simulation analysis showed that residues numbered from 15 to 21 (WKRKRFG in LG21 are involved in interacting with Psl. Our study indicates that host immune systems might detect and interact with microbial biofilms through AMPs. Engineering biofilm EPS-targeting AMPs might provide novel strategies for biofilm detection and treatment.

Inactivation of the rhlA gene in Pseudomonas aeruginosa prevents rhamnolipid production, disabling the protection against polymorphonuclear leukocytes

DEFF Research Database (Denmark)

van Gennip, Maria; Christensen, Louise Dahl; Alhede, Morten

2009-01-01

Many of the virulence factors produced by the opportunistic human pathogen Pseudomonas aeruginosa are quorum-sensing (QS) regulated. Among these are rhamnolipids, which have been shown to cause lysis of several cellular components of the human immune system, e.g. monocyte-derived macrophages and ...

Comparative In Vitro Efficacy of Doripenem and Imipenem Against Multi-Drug Resistant Pseudomonas aeruginosa.

Science.gov (United States)

Wali, Nadia; Mirza, Irfan Ali

2016-04-01

To compare the in vitro efficacy of doripenem and imipenem against multi-drug resistant (MDR) Pseudomonas aeruginosa from various clinical specimens. Descriptive cross-sectional study. Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from November 2012 to November 2013. MDR Pseudomonas aeruginosa isolates from various clinical samples were included in the study. Susceptibility of Pseudomonas aeruginosa against doripenem and imipenem was performed by E-test strip and agar dilution methods. The results were interpreted as recommended by Clinical Laboratory Standard Institute (CLSI) guidelines. The maximum number of Pseudomonas aeruginosa were isolated from pure pus and pus swabs. In vitro efficacy of doripenem was found to be more effective as compared to imipenem against MDR Pseudomonas aeruginosa with both E-test strip and agar dilution methods. Overall, p-values of 0.014 and 0.037 were observed when susceptibility patterns of doripenem and imipenem were evaluated with E-test strip and agar dilution methods. In vitro efficacy of doripenem was found to be better against MDR Pseudomonas aeruginosaas compared to imipenem when tested by both E-test and agar dilution methods.

Efflux pump inhibitors (EPIs as new antimicrobial agents against Pseudomonas aeruginosa

Directory of Open Access Journals (Sweden)

Momen Askoura

2011-05-01

Full Text Available Pseudomonas aeruginosa is an opportunistic human pathogen and one of the leading causes of nosocomial infections worldwide. The difficulty in treatment of pseudomonas infections arises from being multidrug resistant (MDR and exhibits resistance to most antimicrobial agents due to the expression of different mechanisms overcoming their effects. Of these resistance mechanisms, the active efflux pumps in Pseudomonas aeruginosa that belong to the resistance nodulation division (RND plays a very important role in extruding the antibiotics outside the bacterial cells providing a protective means against their antibacterial activity. Beside its role against the antimicrobial agents, these pumps can extrude biocides, detergents, and other metabolic inhibitors. It is clear that efflux pumps can be targets for new antimicrobial agents. Peptidomimetic compounds such as phenylalanine arginyl β-naphthylamide (PAβN have been introduced as efflux pump inhibitors (EPIs; their mechanism of action is through competitive inhibition with antibiotics on the efflux pump resulting in increased intracellular concentration of antibiotic, hence, restoring its antibacterial activity. The advantage of EPIs is the difficulty to develop bacterial resistance against them, but the disadvantage is their toxic property hindering their clinical application. The structure activity relationship of these compounds showed other derivatives from PAβN that are higher in their activity with higher solubility in biological fluids and decreased toxicity level. This raises further questions on how can we compact Pseudomonas infections. Of particular importance, the recent resurgence in the use of older antibiotics such as polymyxins and probably applying stricter control measures in order to prevent their spread in clinical sittings.

Bioleaching of copper oxide ore by Pseudomonas aeruginosa

Science.gov (United States)

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

2013-12-01

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

RNAi screen reveals an Abl kinase-dependent host cell pathway involved in Pseudomonas aeruginosa internalization.

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Julia F Pielage

2008-03-01

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

Subinhibitory concentration of kanamycin induces the Pseudomonas aeruginosa type VI secretion system.

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Cerith Jones

Full Text Available Pseudomonas aeruginosa is a Gram-negative bacterium found in natural environments including plants, soils and warm moist surfaces. This organism is also in the top ten of nosocomial pathogens, and prevalent in cystic fibrosis (CF lung infections. The ability of P. aeruginosa to colonize a wide variety of environments in a lasting manner is associated with the formation of a resistant biofilm and the capacity to efficiently outcompete other microorganisms. Here we demonstrate that sub-inhibitory concentration of kanamycin not only induces biofilm formation but also induces expression of the type VI secretion genes in the H1-T6SS cluster. The H1-T6SS is known for its role in toxin production and bacterial competition. We show that the antibiotic induction of the H1-T6SS only occurs when a functional Gac/Rsm pathway is present. These observations may contribute to understand how P. aeruginosa responds to antibiotic producing competitors. It also suggests that improper antibiotic therapy may enhance P. aeruginosa colonization, including in the airways of CF patients.

A case of orbital apex syndrome due to Pseudomonas aeruginosa infection

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Takeshi Kusunoki

2011-11-01

Full Text Available Orbital apex syndrome is commonly been thought to have a poor prognosis. Many cases of this syndrome have been reported to be caused by paranasal sinus mycosis. We encountered a very rare case (60-year-old woman of sinusitis with orbital apex syndrome due to Pseudomonas aeruginosa infection. She had received insulin and dialysis for diabtes and diabetic nephropathy, moreover anticoagulants after heart by-pass surgery. She underwent endoscopic sinus operation and was treated with antibiotics, but her loss of left vision did not improve. Recently, sinusitis cases due to Pseudomonas aeruginosa were reported to be a increasing. Therefore, we should consider the possibility of Pseudomonas aeruginosa as well as mycosis as infections of the sinus, especially inpatients who are immunocompromised body.

Direct evaluation of Pseudomonas aeruginosa biofilm mediators in a chronic infection model.

Science.gov (United States)

Byrd, Matthew S; Pang, Bing; Hong, Wenzhou; Waligora, Elizabeth A; Juneau, Richard A; Armbruster, Chelsie E; Weimer, Kristen E D; Murrah, Kyle; Mann, Ethan E; Lu, Haiping; Sprinkle, April; Parsek, Matthew R; Kock, Nancy D; Wozniak, Daniel J; Swords, W Edward

2011-08-01

Biofilms contribute to Pseudomonas aeruginosa persistence in a variety of diseases, including cystic fibrosis, burn wounds, and chronic suppurative otitis media. However, few studies have directly addressed P. aeruginosa biofilms in vivo. We used a chinchilla model of otitis media, which has previously been used to study persistent Streptococcus pneumoniae and Haemophilus influenzae infections, to show that structures formed in vivo are biofilms of bacterial and host origin within a matrix that includes Psl, a P. aeruginosa biofilm polysaccharide. We evaluated three biofilm and/or virulence mediators of P. aeruginosa known to affect biofilm formation in vitro and pathogenesis in vivo--bis-(3',5')-cyclic dimeric GMP (c-di-GMP), flagella, and quorum sensing--in a chinchilla model. We show that c-di-GMP overproduction has a positive impact on bacterial persistence, while quorum sensing increases virulence. We found no difference in persistence attributed to flagella. We conclude from these studies that a chinchilla otitis media model provides a means to evaluate pathogenic mediators of P. aeruginosa and that in vitro phenotypes should be examined in multiple infection systems to fully understand their role in disease.

Clinical and Morphological Studies on Spontaneous Cases of Pseudomonas aeruginosa Infections in Birds

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I Dinev1, S Denev2* and G Beev2

2013-07-01

Full Text Available Clinical, pathoanatomical, histological, and bacteriological studies were performed on broiler chickens, growing broiler parents, and growing egg layers, in three different poultry farms, after an outbreak of Pseudomonas aeruginosa infections. The method of contamination of the birds was established. Several local and systemic clinico-morphological forms of spontaneous P. aeruginosa infections in various categories of stock birds were described: cases of P. aeruginosa infection resulting from injection of contaminated vaccines; case of P. aeruginosa infections through contaminated aerosol vaccine and cases of pododermatitis, periarthritis and arthritis in broiler chickens associated with P. aeruginosa infection. In different cases mortality range between 0.5 and 50%. The results showed that apart from embryonic mortality in hatcheries, and septicemic infections in newly hatched chickens, the pathogenicity of P. aeruginosa was associated with localized and systemic lesions in this category, as well as in young and growing birds. On one hand, these results have a theoretical significance, contributing for the confirmation and expansion of the wide array of clinico-morphological forms of P. aeruginosa infections in birds. On the other hand, the knowledge on these forms has a purely practical significance in the diagnostics of P. aeruginosa infections by poultry pathologists and veterinary practitioners.

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

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Mary E. Peek

2012-01-01

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

Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis.

Science.gov (United States)

Johansen, Helle Krogh; Gøtzsche, Peter C

2015-08-23

Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed. This is an update of a previously published review. To assess the effectiveness of vaccination against Pseudomonas aeruginosa in cystic fibrosis. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register using the terms vaccines AND pseudomonas (last search 30 March 2015). We previously searched PubMed using the terms vaccin* AND cystic fibrosis (last search 30 May 2013). Randomised trials (published or unpublished) comparing Pseudomonas aeruginosa vaccines (oral, parenteral or intranasal) with control vaccines or no intervention in cystic fibrosis. The authors independently selected trials, assessed them and extracted data. Six trials were identified. Two trials were excluded since they were not randomised and one old, small trial because it was not possible to assess whether is was randomised. The three included trials comprised 483, 476 and 37 patients, respectively. No data have been published from one of the large trials, but the company stated in a press release that the trial failed to confirm the results from an earlier study and that further clinical development was suspended. In the other large trial, relative risk for chronic infection was 0.91 (95% confidence interval 0.55 to 1.49), and in the small trial, the risk was also close to one. In the large trial, one patient was reported to have died in the observation period. In that trial, 227 adverse events (4 severe) were registered in the vaccine group and 91 (1 severe) in the control group. In this large trial of a vaccine developed against flagella antigens, antibody titres against the epitopes contained in the vaccine were higher in the vaccine group compared to the placebo group (P Vaccines against

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

African Journals Online (AJOL)

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

Serotyping and analysis of produced pigments kinds by Pseudomonas aeruginosa clinical isolates

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Stanković-Nedeljković Nataša

2011-01-01

Full Text Available Background/Aim. Pseudomonas aeruginosa (P. aeruginosa is devided into 20 serotypes on the base of the International Antigenic Typing Scheme. P. aeruginosa serotyping is important because of few reasons but epidemiological is the most important. The aim of the study was serotyping of P. aeruginosa clinical isolates, analysing of single clinical isolates P. aeruginosa present in the particular samples, and analysing of pyocianin and fluorescin production in different isolates of P. aeruginosa. Methods. A total of 223 isolates of P. aeruginosa, isolated in the microbiological laboratory of the Health Center “Aleksinac”, Aleksinac, were examinated. P. aeruginosa isolates were put on the pseudomonas isolation agar, pseudomonas agar base, acetamid agar, asparagin prolin broth, pseudomonas asparagin broth, Bushnnell-Haas agar, cetrimid agar base, King A and King B plates, plates for pyocianin production, plates for fluorescin production and tripticasa soya agar (Himedia. Polyvalent and monovalent serums were used in the agglutination (Biorad. Pigment production was analysed on the bases of growth on the plates for pyocianin and fluorescin production. Results. Serologically, we identificated the serovars as follows: O1, O3, O4, O5, O6, O7, O8, O10, O11 and O12. O1 (38% was the most often serovar, then O11 (19% and O6 (8.6%. A total of 18.6% (42 isolates did not agglutinate with any serum, whereas 21 isolates agglutinated only with polyvalent serum. The majority of P. aeruginosa isolates produced fluorescin, 129 (58.54%, 53 (22.94% produced pyocianin whereas 49 (21.21% isolates produced both pigments. Conclusion. P. aeruginosa was isolated most of the from urine, sputum and other materials. The majority often serovars were O1, O6 and O11. The most of isolates produced fluorescin (58.54%, while 22.94% producted pyocianin and 21.21% both pigments.

[Contribution of blue-green pigments to hemolytic activity of Pseudomonas aeruginosa cultural fluid].

Science.gov (United States)

Pyzh, A É; Nikandrov, V N

2011-01-01

To assess the contribution of blue-green pigments of Pseudomonas aeruginosa to hemolytic activity of its cultural fluid. MATERIALS AND METHODS. Eight hospital strains and reference strain ATCC 15442 were used. Growth dynamics of strains as well as features of accumulation of hemolytic and phospholipase activity were studied. Purified samples of pyoverdin and pyocyanin were extracted by gel-chromatography and chloroform extraction methods. Hemolytic and lecitinase activities of the samples as well as effect of active oxygen scavengers and chelating agents on these activities were studied. Dynamics of accumulation of hemolytic activity significantly differed from that of phospholipase activity when strains were grown in liquid medium. Chromatographic separation of the pigments from cultural fluid supernatants sharply reduced its hemolytic activity. Purified samples of pyoverdin and pyocyanin were capable to lyse erythrocytes and chicken egg lecitin. These characteristics of the pigments were inhibited by nitroblue tetrazolium and sensitive to chelating agents. Conclusion. Pyoverdin and pyocyanin of pathogenic strains of P. aeruginosa are capable to lyse erythrocytes and suspension of purified chicken egg lecitin, they contribute to total hemolytic activity of pathogenic strains of Pseudomonas, which is not determined only by phospholipase C produced by microorganism. Lytic activity of the pigments is blocked by nitroblue tetrazolium and susceptible to some chelating agents. Apparently, this activity is mediated by superoxide radical and determined by presence of metals with transient valence in pigments' molecules.

Pseudomonas aeruginosa Alters Staphylococcus aureus Sensitivity to Vancomycin in a Biofilm Model of Cystic Fibrosis Infection

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Giulia Orazi

2017-07-01

Full Text Available The airways of cystic fibrosis (CF patients have thick mucus, which fosters chronic, polymicrobial infections. Pseudomonas aeruginosa and Staphylococcus aureus are two of the most prevalent respiratory pathogens in CF patients. In this study, we tested whether P. aeruginosa influences the susceptibility of S. aureus to frontline antibiotics used to treat CF lung infections. Using our in vitro coculture model, we observed that addition of P. aeruginosa supernatants to S. aureus biofilms grown either on epithelial cells or on plastic significantly decreased the susceptibility of S. aureus to vancomycin. Mutant analyses showed that 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO, a component of the P. aeruginosa Pseudomonas quinolone signal (PQS system, protects S. aureus from the antimicrobial activity of vancomycin. Similarly, the siderophores pyoverdine and pyochelin also contribute to the ability of P. aeruginosa to protect S. aureus from vancomycin, as did growth under anoxia. Under our experimental conditions, HQNO, P. aeruginosa supernatant, and growth under anoxia decreased S. aureus growth, likely explaining why this cell wall-targeting antibiotic is less effective. P. aeruginosa supernatant did not confer additional protection to slow-growing S. aureus small colony variants. Importantly, P. aeruginosa supernatant protects S. aureus from other inhibitors of cell wall synthesis as well as protein synthesis-targeting antibiotics in an HQNO- and siderophore-dependent manner. We propose a model whereby P. aeruginosa causes S. aureus to shift to fermentative growth when these organisms are grown in coculture, leading to reduction in S. aureus growth and decreased susceptibility to antibiotics targeting cell wall and protein synthesis.

Complement activation by Pseudomonas aeruginosa biofilms

DEFF Research Database (Denmark)

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

1993-01-01

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

Bacteriophage Infectivity Against Pseudomonas aeruginosa in Saline Conditions

KAUST Repository

Scarascia, Giantommaso

2018-05-02

Pseudomonas aeruginosa is a ubiquitous member of marine biofilm, and reduces thiosulfate to produce toxic hydrogen sulfide gas. In this study, lytic bacteriophages were isolated and applied to inhibit the growth of P. aeruginosa in planktonic mode at different temperature, pH, and salinity. Bacteriophages showed optimal infectivity at a multiplicity of infection of 10 in saline conditions, and demonstrated lytic abilities over all tested temperature (25, 30, 37, and 45°C) and pH 6–9. Planktonic P. aeruginosa exhibited significantly longer lag phase and lower specific growth rates upon exposure to bacteriophages. Bacteriophages were subsequently applied to P. aeruginosa-enriched biofilm and were determined to lower the relative abundance of Pseudomonas-related taxa from 0.17 to 5.58% in controls to 0.01–0.61% in treated microbial communities. The relative abundance of Alphaproteobacteria, Pseudoalteromonas, and Planococcaceae decreased, possibly due to the phage-induced disruption of the biofilm matrix. Lastly, when applied to mitigate biofouling of ultrafiltration membranes, bacteriophages were determined to reduce the transmembrane pressure increase by 18% when utilized alone, and by 49% when used in combination with citric acid. The combined treatment was more effective compared with the citric acid treatment alone, which reported ca. 30% transmembrane pressure reduction. Collectively, the findings demonstrated that bacteriophages can be used as a biocidal agent to mitigate undesirable P. aeruginosa-associated problems in seawater applications.

Cell wall glycans and soluble factors determine the interactions between the hyphae of Candida albicans and Pseudomonas aeruginosa.

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Brand, Alexandra; Barnes, Julia D; Mackenzie, Kevin S; Odds, Frank C; Gow, Neil A R

2008-10-01

The fungus, Candida albicans, and the bacterium, Pseudomonas aeruginosa, are opportunistic human pathogens that have been coisolated from diverse body sites. Pseudomonas aeruginosa suppresses C. albicans proliferation in vitro and potentially in vivo but it is the C. albicans hyphae that are killed while yeast cells are not. We show that hyphal killing involves both contact-mediated and soluble factors. Bacterial culture filtrates contained heat-labile soluble factors that killed C. albicans hyphae. In cocultures, localized points of hyphal lysis were observed, suggesting that adhesion and subsequent bacteria-mediated cell wall lysis is involved in the killing of C. albicans hyphae. The glycosylation status of the C. albicans cell wall affected the rate of contact-dependent killing because mutants with severely truncated O-linked, but not N-linked, glycans were hypersensitive to Pseudomonas-mediated killing. Deletion of HWP1, ALS3 or HYR1, which encode major hypha-associated cell wall proteins, had no effect on fungal susceptibility.

Chronic Pseudomonas aeruginosa lung infection in normal and athymic rats

DEFF Research Database (Denmark)

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

1993-01-01

We have compared a chronic lung infection with Pseudomonas aeruginosa embedded in alginate beads in normal and athymic rats with an acute infection with free live P. aeruginosa bacteria. The following parameters were observed and described: mortality, macroscopic and microscopic pathologic changes...

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

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Maria Verônica Guilherme Ferrareze

2007-03-01

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

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

DEFF Research Database (Denmark)

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

2007-01-01

Extracellular DNA is one of the major matrix components in Pseudomonas aeruginosa biofilms. It functions as an intercellular connector and plays a role in stabilization of the biofilms. Evidence that DNA release in P. aeruginosa PAO1 biofilms is controlled by the las-rhl and pqs quorum-sensing sy......Extracellular DNA is one of the major matrix components in Pseudomonas aeruginosa biofilms. It functions as an intercellular connector and plays a role in stabilization of the biofilms. Evidence that DNA release in P. aeruginosa PAO1 biofilms is controlled by the las-rhl and pqs quorum......-sensing systems has been previously presented. This paper provides evidence that DNA release in P. aeruginosa PAO1 biofilms is also under iron regulation. Experiments involving cultivation of P. aeruginosa in microtitre trays suggested that pqs expression, DNA release and biofilm formation were favoured in media...

Chromosomal organization and segregation in Pseudomonas aeruginosa.

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Isabelle Vallet-Gely

2013-05-01

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

Application of bacteriophages to selectively remove Pseudomonas aeruginosa in water and wastewater filtration systems.

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Zhang, Yanyan; Hunt, Heather K; Hu, Zhiqiang

2013-09-01

Water and wastewater filtration systems often house pathogenic bacteria, which must be removed to ensure clean, safe water. Here, we determine the persistence of the model bacterium Pseudomonas aeruginosa in two types of filtration systems, and use P. aeruginosa bacteriophages to determine their ability to selectively remove P. aeruginosa. These systems used beds of either anthracite or granular activated carbon (GAC), which were operated at an empty bed contact time (EBCT) of 45 min. The clean bed filtration systems were loaded with an instantaneous dose of P. aeruginosa at a total cell number of 2.3 (± 0.1 [standard deviation]) × 10(7) cells. An immediate dose of P. aeruginosa phages (1 mL of phage stock at the concentration of 2.7 × 10(7) PFU (Plaque Forming Units)/mL) resulted in a reduction of 50% (± 9%) and >99.9% in the effluent P. aeruginosa concentrations in the clean anthracite and GAC filters, respectively. To further evaluate the effects of P. aeruginosa phages, synthetic stormwater was run through anthracite and GAC biofilters where mixed-culture biofilms were present. Eighty five days after an instantaneous dose of P. aeruginosa (2.3 × 10(7) cells per filter) on day 1, 7.5 (± 2.8) × 10(7) and 1.1 (± 0.5) × 10(7) P. aeruginosa cells/g filter media were detected in the top layer (close to the influent port) of the anthracite and GAC biofilters, respectively, demonstrating the growth and persistence of pathogenic bacteria in the biofilters. A subsequent 1-h dose of phages, at the concentration of 5.1 × 10(6) PFU/mL and flow rate of 1.6 mL/min, removed the P. aeruginosa inside the GAC biofilters and the anthracite biofilters by 70% (± 5%) and 56% (± 1%), respectively, with no P. aeruginosa detected in the effluent, while not affecting ammonia oxidation or the ammonia-oxidizing bacterial community inside the biofilters. These results suggest that phage treatment can selectively remove pathogenic bacteria with minimal impact on beneficial

Identification of Pseudomonas aeruginosa phenazines that kill Caenorhabditis elegans.

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

2013-01-01

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

Identification of Pseudomonas aeruginosa phenazines that kill Caenorhabditis elegans.

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Brent Cezairliyan

2013-01-01

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

The impact of nosocomially-acquired resistant Pseudomonas aeruginosa infection in a burn unit.

Science.gov (United States)

Armour, Alexis D; Shankowsky, Heather A; Swanson, Todd; Lee, Jonathan; Tredget, Edward E

2007-07-01

Nosocomially-acquired Pseudomonas aeruginosa remains a serious cause of infection and septic mortality in burn patients. This study was conducted to quantify the impact of nosocomially-transmitted resistant P. aeruginosa in a burn population. Using a TRACS burn database, 48 patients with P. aeruginosa resistant to gentamicin were identified (Pseudomonas group). Thirty-nine were case-matched to controls without resistant P. aeruginosa cultures (control group) for age, total body surface area, admission year, and presence of inhalation injury. Mortality and various morbidity endpoints were examined, as well as antibiotic costs. There was a significantly higher mortality rate in the Pseudomonas group (33% vs. 8%, p products used (packed cells 51.1 +/- 8.0 vs. 21.1 +/- 3.4, p < 0.01; platelets 11.9 +/- 3.0 vs. 1.4 +/- 0.7, p < 0.01) were all significantly higher in the Pseudomonas group. Cost of antibiotics was also significantly higher ($2,658.52 +/- $647.93 vs. $829.22 +/- $152.82, p < 0.01). Nosocomial colonization or infection, or both, of burn patients with aminoglycoside-resistant P. aeruginosa is associated with significantly higher morbidity, mortality, and cost of care. Increased resource consumption did not prevent significantly higher mortality rates when compared with that of control patients. Thus, prevention, identification, and eradication of nosocomial Pseudomonas contamination are critical for cost-effective, successful burn care.

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

Science.gov (United States)

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

2017-01-01

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

Resistance patterns of Pseudomonas aeruginosa isolated from HIV ...

African Journals Online (AJOL)

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

CXCR1 regulates pulmonary anti-Pseudomonas host defense

Science.gov (United States)

Carevic, M.; Öz, H.; Fuchs, K.; Laval, J.; Schroth, C.; Frey, N.; Hector, A.; Bilich, T.; Haug, M.; Schmidt, A.; Autenrieth, S. E.; Bucher, K.; Beer-Hammer, S.; Gaggar, A.; Kneilling, M.; Benarafa, C.; Gao, J.; Murphy, P.; Schwarz, S.; Moepps, B.; Hartl, D.

2016-01-01

Pseudomonas aeruginosa is a key opportunistic pathogen causing disease in cystic fibrosis (CF) and other lung diseases such as chronic obstructive pulmonary disease (COPD). However, the pulmonary host defense mechanisms regulating anti-Pseudomonas aeruginosa immunity remain incompletely understood. Here we demonstrate, by studying an airway Pseudomonas aeruginosa infection model, in vivo bioluminescence imaging, neutrophil effector responses and human airway samples, that the chemokine receptor CXCR1 regulates pulmonary host defense against Pseudomonas aeruginosa. Mechanistically, CXCR1 regulated anti-Pseudomonas neutrophil responses through modulation of reactive oxygen species and interference with toll-like receptor 5 expression. These studies define CXCR1 as a novel non-canonical chemokine receptor that regulates pulmonary anti-Pseudomonas host defense with broad implications for CF, COPD and other infectious lung diseases. PMID:26950764

Typing of Pseudomonas aeruginosa strains in Norwegian cystic fibrosis patients

DEFF Research Database (Denmark)

Fluge, G; Ojeniyi, B; Høiby, N

2001-01-01

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

Antibiotic Sensitivity in Pseudomonas aeruginosa of Diabetic Patient’s Foot Ulcer

OpenAIRE

Pratiwi Apridamayanti; Khairunnisa Azani Meilinasary; Rafika Sari

2016-01-01

Diabetes Mellitus (DM) patients are at risk to have the diabetic ulcer. The main reason for DM’s patient with ulcer complication to be treated and healed in hospital is bacterial infection. One of many bacteria that infects diabetic ulcer is Pseudomonas aeruginosa. This conditian can be treated by antibiotic. The using antibiotic is often inaccurate causing the microbe resistance. To choose the right antibiotic, it needs to test the antibiotic’s sensitivity towards Pseudomonas aeruginosa. The...

Evolution of metabolic divergence in Pseudomonas aeruginosa during long-term infection facilitates a proto-cooperative interspecies interaction

DEFF Research Database (Denmark)

Frydenlund Michelsen, Charlotte; Khademi, Seyed Mohammad Hossein; Johansen, Helle Krogh

2016-01-01

The effect of polymicrobial interactions on pathogen physiology and how it can act either to limit pathogen colonization or to potentiate pathogen expansion and virulence are not well understood. Pseudomonas aeruginosa and Staphylococcus aureus are opportunistic pathogens commonly found together......1 and DK2-P2M24-2003, which comprised several virulence factors and signaling 4-hydroxy-2-alkylquinoline (HAQ) molecules. Strikingly, a further modulation of the HAQ profile was observed in DK2-P2M24-2003 during interaction with S. aureus, resulting in an area with thickened colony morphology...... host-adapted strain, DK2-P2M24-2003, and S. aureus. In this study, characterization by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) imaging mass spectrometry (IMS) and mass spectral (MS) molecular networking revealed a significant metabolic divergence between P. aeruginosa PAO...

Bioengineered 2'-fucosyllactose and 3-fucosyllactose inhibit the adhesion of Pseudomonas aeruginosa and enteric pathogens to human intestinal and respiratory cell lines.

Science.gov (United States)

Weichert, Stefan; Jennewein, Stefan; Hüfner, Eric; Weiss, Christel; Borkowski, Julia; Putze, Johannes; Schroten, Horst

2013-10-01

Human milk oligosaccharides help to prevent infectious diseases in breastfed infants. Larger scale testing, particularly in animal models and human clinical studies, is still limited due to shortened availability of more complex oligosaccharides. The purpose of this study was to evaluate 2'-fucosyllactose (2'-FL) and 3-fucosyllactose (3-FL) synthesized by whole-cell biocatalysis for their biological activity in vitro. Therefore, we have tested these oligosaccharides for their inhibitory potential of pathogen adhesion in two different human epithelial cell lines. 2'-FL could inhibit adhesion of Campylobacter jejuni, enteropathogenic Escherichia coli, Salmonella enterica serovar fyris, and Pseudomonas aeruginosa to the intestinal human cell line Caco-2 (reduction of 26%, 18%, 12%, and 17%, respectively), as could be shown for 3-FL (enteropathogenic E coli 29%, P aeruginosa 26%). Furthermore, adherence of P aeruginosa to the human respiratory epithelial cell line A549 was significantly inhibited by 2'-FL and 3-FL (reduction of 24% and 23%, respectively). These results confirm the biological and functional activity of biotechnologically synthesized human milk oligosaccharides. Mass-tailored human milk oligosaccharides could be used in the future to supplement infant formula ingredients or as preventatives to reduce the impact of infectious diseases. © 2013 Elsevier Inc. All rights reserved.

Occurrence of bla genes encoding carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii from Intensive Care Unit in a tertiary care hospital.

Science.gov (United States)

Subramaniyan, Jayanthi Siva; Sundaram, Jeya Meenakshi

2018-01-01

ICU shows increasing incidence of infection associated with the use of invasive procedures for the diagnostic purpose as well as the indiscriminate use of antibiotics. Pseudomonas aeruginosa and Acinetobacter species are "very successful" pathogen and the emergence of the Metallo-β-Lactamases (MBL) is becoming a therapeutic challenge. To isolate the Nonfermenting Gram negative bacilli from the ICU samples. To identify the metallo betalactamase producers and to detect the bla gene presence among the Pseudomonas aeruginosa and Acinetobacter baumannii . The Nonfermenting Gram negative bacilli isolates from the ICU samples were taken over for 5 years (2009-2014) in a tertiary care hospital. The isolates of Pseudomonas species and Acinetobacter species were confirmed by API analyser and processed according to standard procedures. Detection of the MBL producers were done by E strip method and subjected for bla gene detection by PCR method. In our study a total of 195 isolates of NFGNB were obtained from various ICU. Of these MBL producers, 26 % were Pseudomonas aeruginosa and 25 % were Acinetobacter baumannii . The subtypes of bla VIM MBL producing P.aeruginosa were 26%. The predominant gene coding for MBL activity in A.baumannii were found to be bla OXA gene 11.9%. The gene accession numbers were KF975367, KF975372. We have to control the development and dissemination of these superbugs among the ICU's.

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

Science.gov (United States)

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

2009-06-01

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

Interleukin-18 impairs the pulmonary host response to Pseudomonas aeruginosa

NARCIS (Netherlands)

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

2003-01-01

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

Molecular Survey of the Occurrence of Legionella spp., Mycobacterium spp., Pseudomonas aeruginosa, and Amoeba Hosts in Two Chloraminated Drinking Water Distribution Systems

Science.gov (United States)

Wang, Hong; Edwards, Marc; Falkinham, Joseph O.

2012-01-01

The spread of opportunistic pathogens via public water systems is of growing concern. The purpose of this study was to identify patterns of occurrence among three opportunistic pathogens (Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa) relative to biotic and abiotic factors in two representative chloraminated drinking water distribution systems using culture-independent methods. Generally, a high occurrence of Legionella (≥69.0%) and mycobacteria (100%), lower occurrence of L. pneumophila (≤20%) and M. avium (≤33.3%), and rare detection of Pseudomonas aeruginosa (≤13.3%) were observed in both systems according to quantitative PCR. Also, Hartmanella vermiformis was more prevalent than Acanthamoeba, both of which are known hosts for opportunistic pathogen amplification, the latter itself containing pathogenic members. Three-minute flushing served to distinguish distribution system water from plumbing in buildings (i.e., premise plumbing water) and resulted in reduced numbers of copies of Legionella, mycobacteria, H. vermiformis, and 16S rRNA genes (P Legionella and H. vermiformis, were noted, emphasizing potential microbial ecological relationships. Overall, the results provide insight into factors that may aid in controlling opportunistic pathogen proliferation in real-world water systems. PMID:22752174

Siderophore-dependent iron uptake systems as gates for antibiotic Trojan horse strategies against Pseudomonas aeruginosa.

Science.gov (United States)

Mislin, Gaëtan L A; Schalk, Isabelle J

2014-03-01

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen responsible for nosocomial infections. The prevalence of antibiotic-resistant P. aeruginosa strains is increasing, necessitating the urgent development of new strategies to improve the control of this pathogen. Its bacterial envelope constitutes of an outer and an inner membrane enclosing the periplasm. This structure plays a key role in the resistance of the pathogen, by decreasing the penetration and the biological impact of many antibiotics. However, this barrier may also be seen as the "Achilles heel" of the bacterium as some of its functions provide opportunities for breaching bacterial defenses. Siderophore-dependent iron uptake systems act as gates in the bacterial envelope and could be used in a "Trojan horse" strategy, in which the conjugation of an antibiotic to a siderophore could significantly increase the biological activity of the antibiotic, by enhancing its transport into the bacterium. In this review, we provide an overview of the various siderophore-antibiotic conjugates that have been developed for use against P. aeruginosa and show that an accurate knowledge of the structural and functional features of the proteins involved in this transmembrane transport is required for the design and synthesis of effective siderophore-antibiotic Trojan horse conjugates.

Chromosomally Encoded mcr-5 in Colistin non-susceptible Pseudomonas aeruginosa.

Science.gov (United States)

Snesrud, Erik; Maybank, Rosslyn; Kwak, Yoon I; Jones, Anthony R; Hinkle, Mary K; Mc Gann, Patrick

2018-05-29

Whole genome sequencing (WGS) of historical Pseudomonas aeruginosa clinical isolates identified a chromosomal copy of mcr-5 within a Tn 3 -like transposon in P. aeruginosa MRSN 12280. The isolate was non-susceptible to colistin by broth microdilution and genome analysis revealed no mutations known to confer colistin resistance. To the best of our knowledge, this is the first report of mcr in colistin non-susceptible P. aeruginosa .

Baicalin inhibits biofilm formation, attenuates the quorum sensing-controlled virulence and enhances Pseudomonas aeruginosa clearance in a mouse peritoneal implant infection model.

Directory of Open Access Journals (Sweden)

Jing Luo

Full Text Available The quorum sensing (QS circuit plays a role in the precise regulation of genes controlling virulence factors and biofilm formation in Pseudomonas aeruginosa. QS-controlled biofilm formation by Pseudomonas aeruginosa in clinical settings has remained controversial due to emerging drug resistance; therefore, screening diverse compounds for anti-biofilm or anti-QS activities is important. This study demonstrates the ability of sub-minimum inhibitory concentrations (sub-MICs of baicalin, an active natural compound extracted from the traditional Chinese medicinal Scutellaria baicalensis, to inhibit the formation of Pseudomonas aeruginosa biofilms and enhance the bactericidal effects of various conventional antibiotics in vitro. In addition, baicalin exerted dose-dependent inhibitory effects on virulence phenotypes (LasA protease, LasB elastase, pyocyanin, rhamnolipid, motilities and exotoxin A regulated by QS in Pseudomonas aeruginosa. Moreover, the expression levels of QS-regulatory genes, including lasI, lasR, rhlI, rhlR, pqsR and pqsA, were repressed after sub-MIC baicalin treatment, resulting in significant decreases in the QS signaling molecules 3-oxo-C12-HSL and C4-HSL, confirming the ability of baicalin-mediated QS inhibition to alter gene and protein expression. In vivo experiments indicated that baicalin treatment reduces Pseudomonas aeruginosa pathogenicity in Caenorhabditis elegans. Greater worm survival in the baicalin-treated group manifested as an increase in the LT50 from 24 to 96 h. In a mouse peritoneal implant infection model, baicalin treatment enhanced the clearance of Pseudomonas aeruginosa from the implants of mice infected with Pseudomonas aeruginosa compared with the control group. Moreover, the combination of baicalin and antibiotics significantly reduced the numbers of colony-forming units in the implants to a significantly greater degree than antibiotic treatment alone. Pathological and histological analyses revealed

Production of Quorum Sensing Inhibitors in Growing Onion Bulbs Infected with Pseudomonas aeruginosa E (HQ324110).

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Abd-Alla, Mohamed H; Bashandy, Shymaa R

2012-01-01

Eighteen organic compounds were present in growing onion bulbs cultivar Giza 6 infected with P. aeruginosa, but only fourteen of them are present in dry infected onion bulbs; however, four compounds were missing in dry onion. The missing compounds in dry infected onion bulbs are pantolactone, 4,5-dihydro-4,5-dimethylfuran-2(3H)-one, myristic acid, and linoleic acid. All of them were detected in growing onion (living cell) during Pseudomonas aeruginosa infection, and it is hypothesized that it may be produced by plants and act as defence system. Pantolactone and myristic acid were selected to explore their effects on growth and virulence factors of Pseudomonas aeruginosa. Exogenous application of pantolactone and myristic acid significantly inhibited pyocyanin production, protease, and lipase and polygalacturonase activity but did not have any significant effects on bacterial growth. The inhibition of virulence factors without reduction in bacterial growth may be providing strong support that these chemical molecules are general quorum sensing inhibitors than an antibacterial effect. Disruption of quorum sensing of pathogen indicates that this new approach has potential in fighting bacterial infections in human and plants.

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

Science.gov (United States)

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

2012-01-01

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

Investigation of the algT operon sequence in mucoid and non-mucoid Pseudomonas aeruginosa isolates from 115 Scandinavian patients with cystic fibrosis and in 88 in vitro non-mucoid revertants

DEFF Research Database (Denmark)

Ciofu, Oana; Lee, Baoleri; Johannesson, Marie

2008-01-01

Pseudomonas aeruginosa is the dominant pathogen causing chronic lung infections in patients with cystic fibrosis (CF). After an initial phase characterized by intermittent colonizations, a chronic infection is established upon conversion of P. aeruginosa from the non-mucoid to the mucoid, alginate...

Comparison of histological lesions in acute hemorrhagic pneumonia in mink associated with Pseudomonas aeruginosa or Escherichia coli

DEFF Research Database (Denmark)

Salomonsen, Charlotte Mark; Boye, Mette; Høiby, N.

2013-01-01

also occurred in farmed mink. The purpose of this study was to compare histological lesions of acute hemorrhagic pneumonia associated with both P. aeruginosa and E. coli in mink, including a description of tissue distribution of pathogens, in an attempt to differentiate between the 2 disease entities......, as P. aeruginosa was most often found surrounding blood vessels and lining the alveoli, while E. coli showed a more diffuse distribution in the lung tissue. Furthermore, P. aeruginosa often elicited a very hemorrhagic response in the lung, while infection with E. coli was associated with a higher......Hemorrhagic pneumonia can be a major cause of mortality in farmed mink in the fall. In its classic form, hemorrhagic pneumonia is caused by the bacterium Pseudomonas aeruginosa. In recent years, however, outbreaks of this type of pneumonia that are associated with hemolytic Escherichia coli have...

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

Science.gov (United States)

Chua, Song Lin; Yam, Joey Kuok Hoong; Hao, Piliang; Adav, Sunil S.; Salido, May Margarette; Liu, Yang; Givskov, Michael; Sze, Siu Kwan; Tolker-Nielsen, Tim; Yang, Liang

2016-01-01

Drug resistance and tolerance greatly diminish the therapeutic potential of antibiotics against pathogens. Antibiotic tolerance by bacterial biofilms often leads to persistent infections, but its mechanisms are unclear. Here we use a proteomics approach, pulsed stable isotope labelling with amino acids (pulsed-SILAC), to quantify newly expressed proteins in colistin-tolerant subpopulations of Pseudomonas aeruginosa biofilms (colistin is a ‘last-resort' antibiotic against multidrug-resistant Gram-negative pathogens). Migration is essential for the formation of colistin-tolerant biofilm subpopulations, with colistin-tolerant cells using type IV pili to migrate onto the top of the colistin-killed biofilm. The colistin-tolerant cells employ quorum sensing (QS) to initiate the formation of new colistin-tolerant subpopulations, highlighting multicellular behaviour in antibiotic tolerance development. The macrolide erythromycin, which has been previously shown to inhibit the motility and QS of P. aeruginosa, boosts biofilm eradication by colistin. Our work provides insights on the mechanisms underlying the formation of antibiotic-tolerant populations in bacterial biofilms and indicates research avenues for designing more efficient treatments against biofilm-associated infections. PMID:26892159

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

Science.gov (United States)

Chua, Song Lin; Yam, Joey Kuok Hoong; Hao, Piliang; Adav, Sunil S; Salido, May Margarette; Liu, Yang; Givskov, Michael; Sze, Siu Kwan; Tolker-Nielsen, Tim; Yang, Liang

2016-02-19

Drug resistance and tolerance greatly diminish the therapeutic potential of antibiotics against pathogens. Antibiotic tolerance by bacterial biofilms often leads to persistent infections, but its mechanisms are unclear. Here we use a proteomics approach, pulsed stable isotope labelling with amino acids (pulsed-SILAC), to quantify newly expressed proteins in colistin-tolerant subpopulations of Pseudomonas aeruginosa biofilms (colistin is a 'last-resort' antibiotic against multidrug-resistant Gram-negative pathogens). Migration is essential for the formation of colistin-tolerant biofilm subpopulations, with colistin-tolerant cells using type IV pili to migrate onto the top of the colistin-killed biofilm. The colistin-tolerant cells employ quorum sensing (QS) to initiate the formation of new colistin-tolerant subpopulations, highlighting multicellular behaviour in antibiotic tolerance development. The macrolide erythromycin, which has been previously shown to inhibit the motility and QS of P. aeruginosa, boosts biofilm eradication by colistin. Our work provides insights on the mechanisms underlying the formation of antibiotic-tolerant populations in bacterial biofilms and indicates research avenues for designing more efficient treatments against biofilm-associated infections.

Quorum-Quenching Human Designer Cells for Closed-Loop Control of Pseudomonas aeruginosa Biofilms.

Science.gov (United States)

Sedlmayer, Ferdinand; Jaeger, Tina; Jenal, Urs; Fussenegger, Martin

2017-08-09

Current antibiotics gradually lose their efficacy against chronic Pseudomonas aeruginosa infections due to development of increased resistance mediated by biofilm formation, as well as the large arsenal of microbial virulence factors that are coordinated by the cell density-dependent phenomenon of quorum sensing. Here, we address this issue by using synthetic biology principles to rationally engineer quorum-quencher cells with closed-loop control to autonomously dampen virulence and interfere with biofilm integrity. Pathogen-derived signals dynamically activate a synthetic mammalian autoinducer sensor driving downstream expression of next-generation anti-infectives. Engineered cells were able to sensitively score autoinducer levels from P. aeruginosa clinical isolates and mount a 2-fold defense consisting of an autoinducer-inactivating enzyme to silence bacterial quorum sensing and a bipartite antibiofilm effector to dissolve the biofilm matrix. The self-guided cellular device fully cleared autoinducers, potentiated bacterial antibiotic susceptibility, substantially reduced biofilms, and alleviated cytotoxicity to lung epithelial cells. We believe this strategy of dividing otherwise coordinated pathogens and breaking up their shielded stronghold represents a blueprint for cellular anti-infectives in the postantibiotic era.

The Effect of Silybin Encapsulated in Nanoparticles on oprM Gene Expression in Drug Resistant Isolates of Pseudomonas Aeruginosa

Directory of Open Access Journals (Sweden)

Aref Mohammadipour

2017-08-01

Full Text Available Abstract Background: Pseudomonas aeruginosa is an opportunistic nosocomial pathogen that using several classes of antibiotics to treat has been led to the emergence of multiple drug resistance. One of the drug resistance mechanisms in Pseudomonas aeruginosa is overexpression of mexXY-oprM efflux pump system. Silybin as main flavonolignan of silymarin extracted from Silybum marianum is a hepatoprotective agent that its anti-bacterial properties was studied, recently. In this study, the effect of combination of silybin and ciprofloxacin on oprM gene expression in clinical isolates of Pseudomonas aeruginosa was evaluated. Materials and Methods: In this study, seven ciprofloxacin resistant isolates of Pseudomonas aeruginosa were treated by ciprofloxacin (1/2MIC only (control sample and in the combination with silybin-encapsulated micelle (nanoparticles (test sample. After 24h, RNA extraction and cDNA synthesis were performed in silybin treated and un-treated cells and oprM gene expression was quantitatively investigated by realtime PCR method. Results: Results of this study showed that a silybin encapsulated in nanoparticles (400µg/ml induces death up to 50% in resistant isolates treated by ciprofloxacin (1/2MIC during 24h. Also, quantitative Real-Time PCR analysis revealed that silybin encapsulated in nanoparticles decreases the expression of oprM gene compared to silybin untreated cells. Conclusion: It seems that Decrease of oprM expression in resistant isolates lead to decrease of mexAB-oprM and mexXY-oprM in cell surface, subsequently decrease of antibiotic withdrawal to extracellular environment and increase of sensitivity to antibiotics.

Investigation of Pseudomonas aeruginosa quorum-sensing signaling system for identifying multiple inhibitors using molecular docking and structural analysis methodology.

Science.gov (United States)

Soheili, Vahid; Bazzaz, Bibi Sedigheh Fazly; Abdollahpour, Nooshin; Hadizadeh, Farzin

2015-12-01

Pseudomonas aeruginosa is an opportunistic human pathogen and a common Gram-negative bacterium in hospital-acquired infections. It causes death in many burn victims, cystic-fibrosis and neutropenic-cancer patients. It is known that P. aeruginosa biofilm maturation and production of cell-associated and extracellular virulence factors such as pyocyanin, elastase and rhamnolipids are under the control of a quorum-sensing (QS) system. Among several proteins involved in the Pseudomonas QS mechanism, LasR and PqsE play an important role in its cascade signaling system. They can cause increases in QS factors, biofilm maturation, and the production of virulence factors. Therefore, inhibition of these proteins can reduce the pathogenicity of P. aeruginosa. According to the structure of corresponding auto-inducers bound to these proteins, in silico calculations were performed with some non-steroidal anti-inflammatory drugs (NSAIDs) to estimate possible interactions and find the co-inhibitors of LasR and PqsE. The results showed that oxicams (Piroxicam and Meloxicam) can interact well with active sites of both proteins with the Ki of 119.43 nM and 4.0 μM for Meloxicam and 201.39 nM and 4.88 μM against LasR and PqsE, respectively. These findings suggested that Piroxicam and Meloxicam can be used as potential inhibitors for control of the P. aeruginosa QS signaling system and biofilm formation, and may be used in the design of multiple inhibitors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Burden of different beta-lactamase classes among clinical isolates of AmpC-producing Pseudomonas aeruginosa in burn patients: A prospective study

OpenAIRE

Kumar, V.; Sen, M. R.; Nigam, C.; Gahlot, R.; Kumari, S.

2012-01-01

Background: Pseudomonas aeruginosa is one of the most common pathogens causing infections in burns, and shows increasing resistance to β-lactam antibiotics by producing different classes of beta-lactamases. It is also not unusual to find a single isolate that expresses multiple β-lactamase enzymes, further complicating the treatment options. Thus, in this study, we aimed to determine the coexistence of different beta-lactamase enzymes in clinical isolates of P. aeruginosa in the burn ward. Ma...

Analysis of Pseudomonas aeruginosa Cell Envelope Proteome by Capture of Surface-Exposed Proteins on Activated Magnetic Nanoparticles

OpenAIRE

Vecchietti, Davide; Di Silvestre, Dario; Miriani, Matteo; Bonomi, Francesco; Marengo, Mauro; Bragonzi, Alessandra; Cova, Lara; Franceschi, Eleonora; Mauri, Pierluigi; Bertoni, Giovanni

2012-01-01

We report on specific magneto-capturing followed by Multidimensional Protein Identification Technology (MudPIT) for the analysis of surface-exposed proteins of intact cells of the bacterial opportunistic pathogen Pseudomonas aeruginosa. The magneto-separation of cell envelope fragments from the soluble cytoplasmic fraction allowed the MudPIT identification of the captured and neighboring proteins. Remarkably, we identified 63 proteins captured directly by nanoparticles and 67 proteins embedde...

Transcriptome Profiling of Antimicrobial Resistance in Pseudomonas aeruginosa.

Science.gov (United States)

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

2016-08-01

Emerging resistance to antimicrobials and the lack of new antibiotic drug candidates underscore the need for optimization of current diagnostics and therapies to diminish the evolution and spread of multidrug resistance. As the antibiotic resistance status of a bacterial pathogen is defined by its genome, resistance profiling by applying next-generation sequencing (NGS) technologies may in the future accomplish pathogen identification, prompt initiation of targeted individualized treatment, and the implementation of optimized infection control measures. In this study, qualitative RNA sequencing was used to identify key genetic determinants of antibiotic resistance in 135 clinical Pseudomonas aeruginosa isolates from diverse geographic and infection site origins. By applying transcriptome-wide association studies, adaptive variations associated with resistance to the antibiotic classes fluoroquinolones, aminoglycosides, and β-lactams were identified. Besides potential novel biomarkers with a direct correlation to resistance, global patterns of phenotype-associated gene expression and sequence variations were identified by predictive machine learning approaches. Our research serves to establish genotype-based molecular diagnostic tools for the identification of the current resistance profiles of bacterial pathogens and paves the way for faster diagnostics for more efficient, targeted treatment strategies to also mitigate the future potential for resistance evolution. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Blue light treatment of Pseudomonas aeruginosa: Strong bactericidal activity, synergism with antibiotics and inactivation of virulence factors.

Science.gov (United States)

Fila, Grzegorz; Kawiak, Anna; Grinholc, Mariusz Stanislaw

2017-08-18

Pseudomonas aeruginosa is among the most common pathogens responsible for both acute and chronic infections of high incidence and severity. Additionally, P. aeruginosa resistance to conventional antimicrobials has increased rapidly over the past decade. Therefore, it is crucial to explore new therapeutic options, particularly options that specifically target the pathogenic mechanisms of this microbe. The ability of a pathogenic bacterium to cause disease is dependent upon the production of agents termed 'virulence factors', and approaches to mitigate these agents have gained increasing attention as new antibacterial strategies. Although blue light irradiation is a promising alternative approach, only limited and preliminary studies have described its effect on virulence factors. The current study aimed to investigate the effects of lethal and sub-lethal doses of blue light treatment (BLT) on P. aeruginosa virulence factors. We analyzed the inhibitory effects of blue light irradiation on the production/activity of several virulence factors. Lethal BLT inhibited the activity of pyocyanin, staphylolysin, pseudolysin and other proteases, but sub-lethal BLT did not affect the production/expression of proteases, phospholipases, and flagella- or type IV pili-associated motility. Moreover, a eukaryotic cytotoxicity test confirmed the decreased toxicity of blue light-treated extracellular P. aeruginosa fractions. Finally, the increased antimicrobial susceptibility of P. aeruginosa treated with sequential doses of sub-lethal BLT was demonstrated with a checkerboard test. Thus, this work provides evidence-based proof of the susceptibility of drug-resistant P. aeruginosa to BLT-mediated killing, accompanied by virulence factor reduction, and describes the synergy between antibiotics and sub-lethal BLT.

Within-host microevolution of Pseudomonas aeruginosa in Italian cystic fibrosis patients

DEFF Research Database (Denmark)

Marvig, Rasmus Lykke; Dolce, Daniela; Madsen Sommer, Lea Mette

2015-01-01

Chronic infection with Pseudomonas aeruginosa is a major cause of morbidity and mortality in cystic fibrosis (CF) patients, and a more complete understanding of P. aeruginosa within-host genomic evolution, transmission, and population genomics may provide a basis for improving intervention strate...

In vitro efficacy of doripenem against pseudomonas aeruginosa and acinetobacter baumannii by e-test

International Nuclear Information System (INIS)

Gilani, M.; Munir, T.; Latif, M.; Rehman, S.

2015-01-01

To assess the in vitro efficacy of doripenem against Pseudomonas aeruginosa and Acinetobacter baumannii using Epsilometer strips. Study Design: Cross-sectional study. Place and Duration of Study: Department of Microbiology, Army Medical College, Rawalpindi and National University of Sciences and Technology, Islamabad, from May 2014 to September 2014. Methodology: A total of 60 isolates of Acinetobacter baumannii and Pseudomonas aeruginosa collected from various clinical samples received from Military Hospital were included in the study. The specimens were inoculated onto blood, MacConkey and chocolate agars. The isolates were identified using Gram staining, motility, catalase test, oxidase test and API 20NE (Biomeriux, France). Organisms identified as Acinetobacter baumannii and Pseudomonas aeruginosa were included in the study. Bacterial suspensions equivalent to 0.5 McFarland turbidity standard of the isolates were prepared and applied on Mueller Hinton agar. Epsilometer strip was placed in the center of the plate and incubated for 18-24 hours. Minimum Inhibitory Concentration (MIC) was taken to be the point where the epsilon intersected the E-strip. MIC of all the isolates was noted. Results: For Pseudomonas aeruginosa isolates, MIC50 was 12 micro g/mL and MIC90 was 32 micro g/mL. For Acinetobacter baumannii MIC 50 and MIC90 was 32 micro g/mL. Conclusion: Doripenem is no more effective against Pseudomonas aeruginosa and Acinetobacter baumannii in our setting. (author)

Promysalin Elicits Species-Selective Inhibition of Pseudomonas aeruginosa by Targeting Succinate Dehydrogenase.

Science.gov (United States)

Keohane, Colleen E; Steele, Andrew D; Fetzer, Christian; Khowsathit, Jittasak; Van Tyne, Daria; Moynié, Lucile; Gilmore, Michael S; Karanicolas, John; Sieber, Stephan A; Wuest, William M

2018-02-07

Natural products have served as an inspiration to scientists both for their complex three-dimensional architecture and exquisite biological activity. Promysalin is one such Pseudomonad secondary metabolite that exhibits narrow-spectrum antibacterial activity, originally isolated from the rhizosphere. We herein utilize affinity-based protein profiling (AfBPP) to identify succinate dehydrogenase (Sdh) as the biological target of the natural product. The target was further validated in silico, in vitro, in vivo, and through the selection, and sequencing, of a resistant mutant. Succinate dehydrogenase plays an essential role in primary metabolism of Pseudomonas aeruginosa as the only enzyme that is involved both in the tricarboxylic acid cycle (TCA) and in respiration via the electron transport chain. These findings add credence to other studies that suggest that the TCA cycle is an understudied target in the development of novel therapeutics to combat P. aeruginosa, a significant pathogen in clinical settings.

Convergent evolution and adaptation of Pseudomonas aeruginosa within patients with cystic fibrosis.

Science.gov (United States)

Marvig, Rasmus Lykke; Sommer, Lea Mette; Molin, Søren; Johansen, Helle Krogh

2015-01-01

Little is known about how within-host evolution compares between genotypically different strains of the same pathogenic species. We sequenced the whole genomes of 474 longitudinally collected clinical isolates of Pseudomonas aeruginosa sampled from 34 children and young individuals with cystic fibrosis. Our analysis of 36 P. aeruginosa lineages identified convergent molecular evolution in 52 genes. This list of genes suggests a role in host adaptation for remodeling of regulatory networks and central metabolism, acquisition of antibiotic resistance and loss of extracellular virulence factors. Furthermore, we find an ordered succession of mutations in key regulatory networks. Accordingly, mutations in downstream transcriptional regulators were contingent upon mutations in upstream regulators, suggesting that remodeling of regulatory networks might be important in adaptation. The characterization of genes involved in host adaptation may help in predicting bacterial evolution in patients with cystic fibrosis and in the design of future intervention strategies.

Expression, purification, crystallization and preliminary crystallographic analysis of PA3885 (TpbA) from Pseudomonas aeruginosa PAO1

International Nuclear Information System (INIS)

Yang, Wen; Li, Kan; Bai, Yuwei; Zhou, Ruimin; Zhou, Weihong; Bartlam, Mark

2010-01-01

PA3885 (TpbA), a tyrosine phosphatase, may function as a balancing factor between biofilm formation and motility in the opportunistic pathogen P. aeruginosa. Here, the expression, purification, crystallization and preliminary crystallographic analysis of PA3885 from P. aeruginosa PAO1 are reported. Biofilms are important in cell communication and growth in most bacteria and are also responsible for most human clinical infections and diseases. Quorum-sensing systems have been identified to be crucial for biofilm formation and regulation. PA3885 (TpbA), a tyrosine phosphatase, is reported to convert extracellular quorum-sensing signals into internal gene-cascade reactions that result in reduced biofilm formation in the opportunistic pathogen Pseudomonas aeruginosa. Here, PA3885 from P. aeruginosa PAO1 was expressed, purified and crystallized. Single crystals were studied by X-ray crystallography and native diffraction data were collected to 2.8 Å resolution. These crystals were determined to belong to space group C2. It was not possible to conclusively determine the number of proteins in the asymmetric unit from the preliminary X-ray diffraction data analysis alone and attempts to determine the crystal structure of PA3885 are currently under way

Always expect the unexpected: lung abscess due to pseudomonas aeruginosa mimicking pulmonary aspergilloma in acute B-cell leukemia.

Science.gov (United States)

Dieks, J-K; von Bueren, A O; Schaefer, I-M; Menke, J; Lex, C; Krause, U; Zenker, D; Kühnle, I; Kramm, C M

2013-11-01

We report on a case of Pseudomonas aeruginosa sepsis and consecutive lung abscess in a 13-year-old patient with acute B-cell leukemia. At first, radiographic findings strongly suggested presence of pulmonary aspergilloma and only microbiological testing of the surgically enucleated mass revealed the correct underlying pathogen and confirmed final diagnosis. © Georg Thieme Verlag KG Stuttgart · New York.

In-vivo expression profiling of Pseudomonas aeruginosa infections reveals niche-specific and strain-independent transcriptional programs.

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Piotr Bielecki

Full Text Available Pseudomonas aeruginosa is a threatening, opportunistic pathogen causing disease in immunocompromised individuals. The hallmark of P. aeruginosa virulence is its multi-factorial and combinatorial nature. It renders such bacteria infectious for many organisms and it is often resistant to antibiotics. To gain insights into the physiology of P. aeruginosa during infection, we assessed the transcriptional programs of three different P. aeruginosa strains directly after isolation from burn wounds of humans. We compared the programs to those of the same strains using two infection models: a plant model, which consisted of the infection of the midrib of lettuce leaves, and a murine tumor model, which was obtained by infection of mice with an induced tumor in the abdomen. All control conditions of P. aeruginosa cells growing in suspension and as a biofilm were added to the analysis. We found that these different P. aeruginosa strains express a pool of distinct genetic traits that are activated under particular infection conditions regardless of their genetic variability. The knowledge herein generated will advance our understanding of P. aeruginosa virulence and provide valuable cues for the definition of prospective targets to develop novel intervention strategies.

Polysaccharides serve as scaffold of biofilms formed by mucoid Pseudomonas aeruginosa

DEFF Research Database (Denmark)

Yang, Liang; Hengzhuang, Wang; Wu, Hong

2012-01-01

Chronic lung infection by mucoid Pseudomonas aeruginosa is one of the major pathologic features in patients with cystic fibrosis. Mucoid P. aeruginosa is notorious for its biofilm forming capability and resistance to immune attacks. In this study, the roles of extracellular polymeric substances f...

Pseudomonas aeruginosa mutations in lasl and rhll quorum sensing systems result in milder chronic lung infection

DEFF Research Database (Denmark)

Wu, H.; Song, Z.J.; Givskov, Michael Christian

2001-01-01

To understand the importance of quorum sensing in chronic Pseudomonas aeruginosa lung infection, the in vivo pathogenic effects of the wild-type P aeruginosa PAO1 and its double mutant, PAO1 lasI rhlI, in which the signal-generating parts of the quorum sensing systems are defective were compared....... The rat model of P. aeruginosa lung infection was used in the present study. The rats were killed on days 3, 7, 14 and 28 after infection with the P. aeruginosa strains. The results showed that during the early stages of infection, the PAO1 double mutant induced a stronger serum antibody response, higher...... number of lung bacteria, and minor serum IgG and IgG1 responses but increased lung interferon gamma production were detected in the group infected with the PAO1 double mutant when compared with the PAO1-infected group. Delayed immune responses were observed in the PAO1-infected group and they might...

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

DEFF Research Database (Denmark)

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

2006-01-01

Surface-associated microbial communities in many cases display dynamic developmental patterns. Model biofilms formed by Pseudomonas aeruginosa and Pseudomonas putida in laboratory flow-chamber setups represent examples of such behaviour. Dependent on the experimental conditions the bacteria...

Análise epidemiológica de isolados clínicos de Pseudomonas aeruginosa provenientes de hospital universitário Epidemiologic analysis of clinical isolates of Pseudomonas aeruginosa from an university hospital

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Eduardo José Valença Cordeiro Pires

2009-12-01

Full Text Available OBJETIVOS: A Pseudomonas aeruginosa é um patógeno oportunista que tem se destacado quanto à prevalência em casos de infecções hospitalares. Sua ampla resistência aos diversos grupos de antimicrobianos garante a este microrganismo um papel de destaque entre as bactérias mais prevalentes associadas à infecção nosocomial. O objetivo deste estudo foi realizar um levantamento epidemiológico da P. aeruginosa, bem como do seu perfil de susceptibilidade aos antimicrobianos no Hospital das Clínicas da Universidade Federal de Pernambuco. MÉTODOS: Foi realizado um estudo retrospectivo baseado no livro de registro de secreções diversas do laboratório de bacteriologia do Hospital das Clínicas no período compreendido entre janeiro a junho de 2008. Entre os registros, identificamos aqueles que foram positivos para a P. aeruginosa, analisando sua origem e perfil de susceptibilidade aos antimicrobianos utilizados na rotina daquele laboratório. RESULTADOS: As bactérias mais freqüentes, isoladas das secreções diversas, foram P. aeruginosa (26% e S. aureus (25%. Quanto à origem, a P. aeruginosa foi isolada principalmente de infecções respiratórias, pois 33% das amostras positivas para esta bactéria foram provinientes de secreções traqueais e 21% nasais. Os antimicrobianos mais eficazes contra a P. aeruginosa foram: amicacina, imipenem, meropenem e aztreonam. CONCLUSÕES: Estes resultados mostram uma alta prevalência de P. aeruginosa, no Hospital das Clínicas da Universidade Federal de Pernambuco. Apesar de apresentar grande resistência a antimicrobianos mais antigos como as cefalosporinas de primeira e segunda geração, assim como cloranfenicol, em geral, este patógeno demonstrou boa sensibilidade às drogas utilizadas na rotina deste hospital.OBJECTIVES: Pseudomonas aeruginosa is an increasingly prevalent opportunistic pathogen in hospital infection cases. Its high resistance rates to many antimicrobials has given this

Peptidoglycan transpeptidase inhibition in Pseudomonas aeruginosa and Escherichia coli by Penicillins and Cephalosporins.

Science.gov (United States)

Moore, B A; Jevons, S; Brammer, K W

1979-04-01

Peptidoglycan transpeptidase activity has been studied in cells of Escherichia coli 146 and Pseudomonas aeruginosa 56 made permeable to exogenous, nucleotide-sugar peptidoglycan precursors by ether treatment. Transpeptidase activity was inhibited, in both organisms, by a range of penicillins and cephalosporins, the Pseudomonas enzyme being more sensitive to inhibition in each case. Conversely, growth of E. coli 146 was more susceptible to these antibiotics than growth of P. aeruginosa 56. Furthermore, similar transpeptidase inhibition values were ob-obtained for the four penicillins examined against the Pseudomonas enzyme, although only two of these (carbenicillin and pirbenicillin) inhibited the growth of this organism. We therefore conclude that the high resistance of P. aeruginosa 56 to growth inhibition by most beta-lactam antibiotics cannot be due to an insensitive peptidoglycan transpeptidase.

Chronic Pseudomonas aeruginosa biofilm infection impairs murine S100A8/A9 and neutrophil effector cytokines—implications for delayed wound closure?

DEFF Research Database (Denmark)

Trøstrup, Hannah; Lerche, Christian Johann; Christophersen, Lars Jackie

2017-01-01

The impact of Pseudomonas aeruginosa biofilm infections in chronic wounds and clinical implication for healing is receiving increased attention. However, the pathophysiology of host/pathogen interplay is not fully understood. By further revealing the mechanisms, necessary new treatment strategies...

Introduction of Pseudomonas aeruginosa into a Hospital via Vegetables

Science.gov (United States)

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

1972-01-01

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

Balneotherapy is a potential risk factor for Pseudomonas aeruginosa colonization

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Gabriela Deutsch

Full Text Available ABSTRACT The practice of immersion in burn patient has been abandoned in many parts of the world but in Brazil it is still common. The aim of this study was to ascertain if balneotherapy is a risk factor for Pseudomonas aeruginosa colonization in thermally injured patients. Eighteen patients from a Burn Center were studied for 14 weeks for Pseudomonas aeruginosa. Samples were collected by swabbing the exudate of wounds, before and after giving bath to the patients and from balneotherapy table. Pulsed-field gel electrophoresis was used to determine bacterial genetic relatedness. Thirty-seven P. aeruginosa isolates were detected from 292 swabs collected from patients' burn surface area and from the balneotherapy table. Profile analysis of P. aeruginosa DNA fragmentation showed 10 clones among the 37 strains analyzed. Type A is the most prevalent clone, with 23 strains distributed into eight subtypes. These were present in the swabs collected, before and after the patients' bath, from the surface of the bath table, suggesting that there was cross-contamination between the patients in different ways. This work demonstrates that balneotherapy is a risk factor in the Burn Center studied, because the same clone was found among P. aeruginosa isolates collected at various points and times.

ANTIMICROBIAL ACTIVITY OF PINEAPPLE (ANANAS COMOSUS L. MERR EXTRACT AGAINST MULTIDRUG-RESISTANT OF PSEUDOMONAS AERUGINOSA: AN IN VITRO STUDY

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Rahmat Sayyid Zharfan

2017-08-01

Full Text Available Pseudomonas aeruginosa is the main cause of nosocomial infection which is responsible for 10% of hospital-acquired infection. Pseudomonas aeruginosa tends to mutate and displays potential for development of antibiotic resistance. Approximately, 10% of global bacterial isolates are found as Multidrug-resistant Pseudomonas aeruginosa. Pseudomonas aeruginosa have a quite tremendous severity index, especially on pneumonia and urinary tract infections, even sepsis, which 50% mortality rate. Pineapple (Ananas comosus L. Merr has antimicrobial properties. The active antimicrobial compounds in Ananas comosus L. Merr include saponin and bromelain. This research aims to find the potency of antimicrobial effect of pineapple (Ananas comosus L. Merr extract towards Multidrug-resistant Pseudomonas aeruginosa. Multidrug-resistant Pseudomonas aeruginosa specimen is obtained from patient’s pus in orthopaedic department, Dr Soetomo Public Hospital, Surabaya. Multidrug-resistant Pseudomonas aeruginosa specimen is resistant to all antibiotic agents except cefoperazone-sulbactam. This research is conducted by measuring the Minimum Inhibitory Concentration (MIC through dilution test with Mueller-Hinton broth medium. Pineapple extract (Ananas comosus L. Merr. is dissolved in aquadest, then poured into test tube at varying concentrations (6 g/ml; 3 g/ml; 1.5 g/ml; 0.75 g/ml, 0.375 g/ml; and 0.1875 g/ml. After 24 hours’ incubation, samples are plated onto nutrient agar plate, to determine the Minimum Bactericidal Concentration (MBC. The extract of pineapple (Ananas comosus L. Merr has antimicrobial activities against Multidrug-resistant Pseudomonas aeruginosa. Minimum Inhibitory Concentration (MIC could not be determined, because turbidity changes were not seen. The Minimum Bactericidal Concentration (MBC of pineapple extract (Ananas comosus L. Merr to Multidrug-resistant Pseudomonas aeruginosa is 0.75 g/ml. Further study of in vivo is needed.

Acquisition and Role of Molybdate in Pseudomonas aeruginosa

Science.gov (United States)

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

2014-01-01

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

The Pseudomonas Quinolone Signal (PQS)

DEFF Research Database (Denmark)

Sams, Thomas; Baker, Ysobel; Hodgkinson, James

2015-01-01

Pseudomonas aeruginosa is an opportunistichuman pathogen that routinely appears near the top ofpublic health threat lists worldwide. P. aeruginosa causes in-fections by secreting a wealth of exceptionally active exo-products, leading to tissue damage. The synthesis of manyof these virulence factors...

A systematic review and meta-Analyses show that carbapenem use and medical devices are the leading risk factors for carbapenem- resistant pseudomonas aeruginosa

NARCIS (Netherlands)

A.F. Voor (Anne); J.A. Severin (Juliëtte); E.M.E.H. Lesaffre (Emmanuel); M.C. Vos (Margreet)

2014-01-01

textabstractA systematic review and meta-Analyses were performed to identify the risk factors associated with carbapenem-resistant Pseudomonas aeruginosa and to identify sources and reservoirs for the pathogen. A systematic search of PubMed and Embase databases from 1 January 1987 until 27 January

33 original article infections a pseudomonas aeruginosa dans un

African Journals Online (AJOL)

boaz

COPYRIGHT 2014. AFR. J. CLN. EXPER. .... Effective management of P. aeruginosa infections requires good ... a guide for doctors managing patients with. Pseudomonas .... Principles and practice of infectious diseases.5th edition. Edited by ...

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

Science.gov (United States)

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.

Biotransformation of myrcene by Pseudomonas aeruginosa

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Hashemi Elham

2011-05-01

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

The Enzymes of the Ammonia Assimilation in Pseudomonas aeruginosa

NARCIS (Netherlands)

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

1980-01-01

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

Effects of ginseng on Pseudomonas aeruginosa motility and biofilm formation

DEFF Research Database (Denmark)

Wu, Hong; Lee, Baoleri; Yang, Liang

2011-01-01

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

Heavy Metal uptake Potentials of Pseudomonas aeruginosa and ...

African Journals Online (AJOL)

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

The resveratrol tetramer (--hopeaphenol inhibits type III secretion in the gram-negative pathogens Yersinia pseudotuberculosis and Pseudomonas aeruginosa.

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Caroline E Zetterström

Full Text Available Society faces huge challenges, as a large number of bacteria have developed resistance towards many or all of the antibiotics currently available. Novel strategies that can help solve this problem are urgently needed. One such strategy is to target bacterial virulence, the ability to cause disease e.g., by inhibition of type III secretion systems (T3SSs utilized by many clinically relevant gram-negative pathogens. Many of the antibiotics used today originate from natural sources. In contrast, most virulence-blocking compounds towards the T3SS identified so far are small organic molecules. A recent high-throughput screening of a prefractionated natural product library identified the resveratrol tetramer (--hopeaphenol as an inhibitor of the T3SS in Yersinia pseudotuberculosis. In this study we have investigated the virulence blocking properties of (--hopeaphenol in three different gram-negative bacteria. (--Hopeaphenol was found to have micromolar activity towards the T3SSs in Yersinia pseudotuberculosis and Pseudomonas aeruginosa in cell-based infection models. In addition (--hopeaphenol reduced cell entry and subsequent intracellular growth of Chlamydia trachomatis.

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

Science.gov (United States)

Bosire, Erick M; Blank, Lars M; Rosenbaum, Miriam A

2016-08-15

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. 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 entire microbial

Glycan involvement in the adhesion of Pseudomonas aeruginosa to tears.

Science.gov (United States)

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

2016-04-01

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

Challenges with current inhaled treatments for chronic Pseudomonas aeruginosa infection in patients with cystic fibrosis.

LENUS (Irish Health Repository)

Greally, Peter

2012-06-01

Pseudomonas aeruginosa (Pa) is the predominant pathogen infecting the airways of patients with cystic fibrosis (CF). Initial colonization is usually transient and associated with non-mucoid strains, which can be eradicated if identified early. This strategy can prevent, or at least delay, chronic Pa infection, which eventually develops in the majority of patients by their late teens or early adulthood. This article discusses the management and latest treatment developments of Pa lung infection in patients with CF, with a focus on nebulized antibiotic therapy.

Comprehensive MALDI-TOF biotyping of the non-redundant Harvard Pseudomonas aeruginosa PA14 transposon insertion mutant library.

Science.gov (United States)

Oumeraci, Tonio; Jensen, Vanessa; Talbot, Steven R; Hofmann, Winfried; Kostrzewa, Markus; Schlegelberger, Brigitte; von Neuhoff, Nils; Häussler, Susanne

2015-01-01

Pseudomonas aeruginosa is a gram-negative bacterium that is ubiquitously present in the aerobic biosphere. As an antibiotic-resistant facultative pathogen, it is a major cause of hospital-acquired infections. Its rapid and accurate identification is crucial in clinical and therapeutic environments. In a large-scale MALDI-TOF mass spectrometry-based screen of the Harvard transposon insertion mutant library of P. aeruginosa strain PA14, intact-cell proteome profile spectra of 5547 PA14 transposon mutants exhibiting a plethora of different phenotypes were acquired and analyzed. Of all P. aeruginosa PA14 mutant profiles 99.7% were correctly identified as P. aeruginosa with the Biotyper software on the species level. On the strain level, 99.99% of the profiles were mapped to five different individual P. aeruginosa Biotyper database entries. A principal component analysis-based approach was used to determine the most important discriminatory mass features between these Biotyper groups. Although technical replicas were consistently categorized to specific Biotyper groups in 94.2% of the mutant profiles, biological replicas were not, indicating that the distinct proteotypes are affected by growth conditions. The PA14 mutant profile collection presented here constitutes the largest coherent P. aeruginosa MALDI-TOF spectral dataset publicly available today. Transposon insertions in thousands of different P. aeruginosa genes did not affect species identification from MALDI-TOF mass spectra, clearly demonstrating the robustness of the approach. However, the assignment of the individual spectra to sub-groups proved to be non-consistent in biological replicas, indicating that the differentiation between biotyper groups in this nosocomial pathogen is unassured.

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

International Nuclear Information System (INIS)

Rehse, Steven J.; Diedrich, Jonathan; Palchaudhuri, Sunil

2007-01-01

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

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

Directory of Open Access Journals (Sweden)

Nicola Ivan Lorè

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

Synergistic Efficacy of Aedes aegypti Antimicrobial Peptide Cecropin A2 and Tetracycline against Pseudomonas aeruginosa

Science.gov (United States)

Zheng, Zhaojun; Tharmalingam, Nagendran; Liu, Qingzhong; Kim, Wooseong; Fuchs, Beth Burgwyn; Zhang, Rijun; Vilcinskas, Andreas

2017-01-01

ABSTRACT The increasing prevalence of antibiotic resistance has created an urgent need for alternative drugs with new mechanisms of action. Antimicrobial peptides (AMPs) are promising candidates that could address the spread of multidrug-resistant bacteria, either alone or in combination with conventional antibiotics. We studied the antimicrobial efficacy and bactericidal mechanism of cecropin A2, a 36-residue α-helical cationic peptide derived from Aedes aegypti cecropin A, focusing on the common pathogen Pseudomonas aeruginosa. The peptide showed little hemolytic activity and toxicity toward mammalian cells, and the MICs against most clinical P. aeruginosa isolates were 32 to 64 μg/ml, and its MICs versus other Gram-negative bacteria were 2 to 32 μg/ml. Importantly, cecropin A2 demonstrated synergistic activity against P. aeruginosa when combined with tetracycline, reducing the MICs of both agents by 8-fold. The combination was also effective in vivo in the P. aeruginosa/Galleria mellonella model (P < 0.001). We found that cecropin A2 bound to P. aeruginosa lipopolysaccharides, permeabilized the membrane, and interacted with the bacterial genomic DNA, thus facilitating the translocation of tetracycline into the cytoplasm. In summary, the combination of cecropin A2 and tetracycline demonstrated synergistic antibacterial activity against P. aeruginosa in vitro and in vivo, offering an alternative approach for the treatment of P. aeruginosa infections. PMID:28483966

Effective Biosurfactants Production by Pseudomonas aeruginosa and its Efficacy on Different Oils

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Sarita Kumari

2010-07-01

Full Text Available A rhamnolipid producing bacterium, Pseudomonas aeruginosa was isolated from contaminated soil with oily wastes. The Pseudomonas aeruginosa grown with glucose and corn oil as a carbon source produced bio-surfactant. This biosurfactant was purified by procedures that included chloroform-ethanol extraction and 0.05M bicarbonate treatments. The active compound was identified as rhamnolipid by using thin layer chromatography. The emulsification activity of bio-surfactant, the coconut oil responded better than the olive oil, groundnut oil and sunflower oil and gave a maximum level of 1 cm.

[Cervical lymphoadenopathy due to Pseudomonas aeruginosa following mesotherapy].

Science.gov (United States)

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

2009-09-01

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

Pseudomonas aeruginosa biofilms in cystic fibrosis

DEFF Research Database (Denmark)

Høiby, Niels; Ciofu, Oana; Bjarnsholt, Thomas

2010-01-01

The persistence of chronic Pseudomonas aeruginosa lung infections in cystic fibrosis (CF) patients is due to biofilm-growing mucoid (alginate-producing) strains. A biofilm is a structured consortium of bacteria, embedded in a self-produced polymer matrix consisting of polysaccharide, protein...... and DNA. In CF lungs, the polysaccharide alginate is the major part of the P. aeruginosa biofilm matrix. Bacterial biofilms cause chronic infections because they show increased tolerance to antibiotics and resist phagocytosis, as well as other components of the innate and the adaptive immune system....... As a consequence, a pronounced antibody response develops, leading to immune complex-mediated chronic inflammation, dominated by polymorphonuclear leukocytes. The chronic inflammation is the major cause of the lung tissue damage in CF. Biofilm growth in CF lungs is associated with an increased frequency...

Comparative activities of ciprofloxacin, ticarcillin, and tobramycin against experimental Pseudomonas aeruginosa pneumonia.

OpenAIRE

Schiff, J B; Small, G J; Pennington, J E

1984-01-01

The therapeutic efficacy of ciprofloxacin, an investigational quinoline derivative, was compared with those of ticarcillin and tobramycin in guinea pigs with experimental Pseudomonas aeruginosa pneumonia. Guinea pigs challenged with tracheal instillations of 10(8) CFU of P. aeruginosa developed acute pneumonia, for which survival rates were: controls, 0%; ticarcillin treatment, 37%; ciprofloxacin treatment, 57%; and tobramycin treatment, 69%. Intrapulmonary killing of P. aeruginosa was greate...

A novel porcine model of ventilator-associated pneumonia caused by oropharyngeal challenge with Pseudomonas aeruginosa.

Science.gov (United States)

Li Bassi, Gianluigi; Rigol, Montserrat; Marti, Joan-Daniel; Saucedo, Lina; Ranzani, Otavio T; Roca, Ignasi; Cabanas, Maria; Muñoz, Laura; Giunta, Valeria; Luque, Nestor; Rinaudo, Mariano; Esperatti, Mariano; Fernandez-Barat, Laia; Ferrer, Miquel; Vila, Jordi; Ramirez, Jose; Torres, Antoni

2014-05-01

Animal models of ventilator-associated pneumonia (VAP) in primates, sheep, and pigs differ in the underlying pulmonary injury, etiology, bacterial inoculation methods, and time to onset. The most common ovine and porcine models do not reproduce the primary pathogenic mechanism of the disease, through the aspiration of oropharyngeal pathogens, or the most prevalent human etiology. Herein the authors characterize a novel porcine model of VAP due to aspiration of oropharyngeal secretions colonized by Pseudomonas aeruginosa. Ten healthy pigs were intubated, positioned in anti-Trendelenburg, and mechanically ventilated for 72 h. Three animals did not receive bacterial challenge, whereas in seven animals, a P. aeruginosa suspension was instilled into the oropharynx. Tracheal aspirates were cultured and respiratory mechanics were recorded. On autopsy, lobar samples were obtained to corroborate VAP through microbiological and histological studies. In animals not challenged, diverse bacterial colonization of the airways was found and monolobar VAP rarely developed. In animals with P. aeruginosa challenge, colonization of tracheal secretion increased up to 6.39 ± 0.34 log colony-forming unit (cfu)/ml (P VAP was confirmed in six of seven pigs, in 78% of the cases developed in the dependent lung segments (right medium and lower lobes, P = 0.032). The static respiratory system elastance worsened to 41.5 ± 5.8 cm H2O/l (P = 0.001). The authors devised a VAP model caused by aspiration of oropharyngeal P. aeruginosa, a frequent causative pathogen of human VAP. The model also overcomes the practical and legislative limitations associated with the use of primates. The authors' model could be employed to study pathophysiologic mechanisms, as well as novel diagnostic/preventive strategies.

Pseudomonas aeruginosa RhlR is required to neutralize the cellular immune response in a Drosophila melanogaster oral infection model

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Limmer, Stefanie; Haller, Samantha; Drenkard, Eliana; Lee, Janice; Yu, Shen; Kocks, Christine; Ausubel, Frederick M.; Ferrandon, Dominique

2011-01-01

An in-depth mechanistic understanding of microbial infection necessitates a molecular dissection of host–pathogen relationships. Both Drosophila melanogaster and Pseudomonas aeruginosa have been intensively studied. Here, we analyze the infection of D. melanogaster by P. aeruginosa by using mutants in both host and pathogen. We show that orally ingested P. aeruginosa crosses the intestinal barrier and then proliferates in the hemolymph, thereby causing the infected flies to die of bacteremia. Host defenses against ingested P. aeruginosa included an immune deficiency (IMD) response in the intestinal epithelium, systemic Toll and IMD pathway responses, and a cellular immune response controlling bacteria in the hemocoel. Although the observed cellular and intestinal immune responses appeared to act throughout the course of the infection, there was a late onset of the systemic IMD and Toll responses. In this oral infection model, P. aeruginosa PA14 did not require its type III secretion system or other well-studied virulence factors such as the two-component response regulator GacA or the protease AprA for virulence. In contrast, the quorum-sensing transcription factor RhlR, but surprisingly not LasR, played a key role in counteracting the cellular immune response against PA14, possibly at an early stage when only a few bacteria are present in the hemocoel. These results illustrate the power of studying infection from the dual perspective of host and pathogen by revealing that RhlR plays a more complex role during pathogenesis than previously appreciated. PMID:21987808

Pseudomonas aeruginosa endophthalmitis masquerading as chronic uveitis

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Kalpana Badami Nagaraj

2013-01-01

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

Nosocomial outbreak of Pseudomonas aeruginosa endophthalmitis.

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

2006-11-01

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

Mecanismos de Adherencia de Pseudomonas aeruginosa a nuevos Biomateriales de uso Médico.

OpenAIRE

Martínez Martínez, Luis

2017-01-01

En 1882 Gessard aisló por primera vez Pseudomonas aeruginosa (Bacillus pyoceaneus) de muestras procedentes de heridas quirúrgicas. Hasta 1947 sólo se conocían 91 casos de bacteriemia por este microorganismo, pero en la década actual, cien años después de su descripción, Pseudomonas aeruginosa, ha pasado a ser un microorganismo de creciente interés en patología humana debido a su estrecha relación con enfermos inmun...

The Antimicrobial Effect of Methanolic Extracts of Achillea wilhelmsii, Myrtus communis, and Allium sativum on Pseudomonas aeruginosa

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Mehdi Rostami Rad

2017-12-01

  In this study, the effect of Achillea Wilhelmsii, Myrtus communis, and Allium sativum extracts, was investigated on 4 strains of Pseudomonas aeruginosa, and the effect of each extract, was studied using agar dilution method.   Among these three extracts, the Allium sativum  extract showed the highest antimicrobial activity. Also, observations were indicative of difference in the susceptibility of the studied strains to different extracts, which showed different reactions to each of the extracts based on the origin and antibiotic resistance level.   According to the results of this study, extracts are a natural and valuable sources to produce antimicrobial drugs against pseudomonas strains and other resistant pathogenic bacteria.    

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

Science.gov (United States)

2016-03-15

RESEARCH ARTICLE Biofilm Formation Mechanisms of Pseudomonas aeruginosa Predicted via Genome-Scale Kinetic Models of Bacterial Metabolism Francisco G...jaques.reifman.civ@mail.mil Abstract A hallmark of Pseudomonas aeruginosa is its ability to establish biofilm -based infections that are difficult to...eradicate. Biofilms are less susceptible to host inflammatory and immune responses and have higher antibiotic tolerance than free-living planktonic

Inhibition and dispersal of Agrobacterium tumefaciens biofilms by a small diffusible Pseudomonas aeruginosa exoproduct(s).

Science.gov (United States)

Hibbing, Michael E; Fuqua, Clay

2012-06-01

Environmental biofilms often contain mixed populations of different species. In these dense communities, competition between biofilm residents for limited nutrients such as iron can be fierce, leading to the evolution of competitive factors that affect the ability of competitors to grow or form biofilms. We have discovered a compound(s) present in the conditioned culture fluids of Pseudomonas aeruginosa that disperses and inhibits the formation of biofilms produced by the facultative plant pathogen Agrobacterium tumefaciens. The inhibitory activity is strongly induced when P. aeruginosa is cultivated in iron-limited conditions, but it does not function through iron sequestration. In addition, the production of the biofilm inhibitory activity is not regulated by the global iron regulatory protein Fur, the iron-responsive extracytoplasmic function σ factor PvdS, or three of the recognized P. aeruginosa quorum-sensing systems. In addition, the compound(s) responsible for the inhibition and dispersal of A. tumefaciens biofilm formation is likely distinct from the recently identified P. aeruginosa dispersal factor, cis-2-decenoic acid (CDA), as dialysis of the culture fluids showed that the inhibitory compound was larger than CDA and culture fluids that dispersed and inhibited biofilm formation by A. tumefaciens had no effect on biofilm formation by P. aeruginosa.

Pseudomonas aeruginosa mutations in lasI and rhlI quorum sensing systems result in milder chronic lung infection

DEFF Research Database (Denmark)

Wu, H; Song, Z; Givskov, Michael

2001-01-01

To understand the importance of quorum sensing in chronic Pseudomonas aeruginosa lung infection, the in vivo pathogenic effects of the wild-type P. aeruginosa PAO1 and its double mutant, PAO1 lasI rhlI, in which the signal-generating parts of the quorum sensing systems are defective were compared....... The rat model of P. aeruginosa lung infection was used in the present study. The rats were killed on days 3, 7, 14 and 28 after infection with the P. aeruginosa strains. The results showed that during the early stages of infection, the PAO1 double mutant induced a stronger serum antibody response, higher...... number of lung bacteria, and minor serum IgG and IgG1 responses but increased lung interferon gamma production were detected in the group infected with the PAO1 double mutant when compared with the PAO1-infected group. Delayed immune responses were observed in the PAO1-infected group and they might...

Pseudomonas aeruginosa. Vacunas: un reto a la investigación

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Sara C. Esnard

2004-04-01

Full Text Available Pseudomonas aeruginosa, patógeno gramnegativo versátil y oportunista debido a su gran adaptabilidad fisiológica, potencial metabólico y mecanismos de virulencia, es causa frecuente a escala mundial de severas o letales infecciones en pacientes hospitalizados. El empeño por lograr terapias alternativas para prevenir o combatir las infecciones producidas por P. aeruginosa ha ocupado a investigadores de todo el mundo desde la segunda mitad del pasado siglo y actualmente se continúan reportando trabajos que respaldan los ensayos de candidatos vacunales, fundamentalmente a partir de antígenos proteicos, mayoritariamente basados en la construcción de vacunas recombinantes. En este artículo se presenta una revisión de trabajos publicados sobre las investigaciones desarrolladas en diferentes países, con el objetivo de obtener candidatos vacunales para la prevención o tratamiento de las infecciones causadas por Pseudomonas aeruginosa, a partir de la década de los años 50 del siglo XX hasta el 2003.

Analysis of Pseudomonas aeruginosa cell envelope proteome by capture of surface-exposed proteins on activated magnetic nanoparticles.

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Davide Vecchietti

Full Text Available We report on specific magneto-capturing followed by Multidimensional Protein Identification Technology (MudPIT for the analysis of surface-exposed proteins of intact cells of the bacterial opportunistic pathogen Pseudomonas aeruginosa. The magneto-separation of cell envelope fragments from the soluble cytoplasmic fraction allowed the MudPIT identification of the captured and neighboring proteins. Remarkably, we identified 63 proteins captured directly by nanoparticles and 67 proteins embedded in the cell envelope fragments. For a high number of proteins, our analysis strongly indicates either surface exposure or localization in an envelope district. The localization of most identified proteins was only predicted or totally unknown. This novel approach greatly improves the sensitivity and specificity of the previous methods, such as surface shaving with proteases that was also tested on P. aeruginosa. The magneto-capture procedure is simple, safe, and rapid, and appears to be well-suited for envelope studies in highly pathogenic bacteria.

Analysis of Pseudomonas aeruginosa Cell Envelope Proteome by Capture of Surface-Exposed Proteins on Activated Magnetic Nanoparticles

Science.gov (United States)

Vecchietti, Davide; Di Silvestre, Dario; Miriani, Matteo; Bonomi, Francesco; Marengo, Mauro; Bragonzi, Alessandra; Cova, Lara; Franceschi, Eleonora; Mauri, Pierluigi; Bertoni, Giovanni

2012-01-01

We report on specific magneto-capturing followed by Multidimensional Protein Identification Technology (MudPIT) for the analysis of surface-exposed proteins of intact cells of the bacterial opportunistic pathogen Pseudomonas aeruginosa. The magneto-separation of cell envelope fragments from the soluble cytoplasmic fraction allowed the MudPIT identification of the captured and neighboring proteins. Remarkably, we identified 63 proteins captured directly by nanoparticles and 67 proteins embedded in the cell envelope fragments. For a high number of proteins, our analysis strongly indicates either surface exposure or localization in an envelope district. The localization of most identified proteins was only predicted or totally unknown. This novel approach greatly improves the sensitivity and specificity of the previous methods, such as surface shaving with proteases that was also tested on P. aeruginosa. The magneto-capture procedure is simple, safe, and rapid, and appears to be well-suited for envelope studies in highly pathogenic bacteria. PMID:23226459

Early aggressive eradication therapy for intermittent Pseudomonas aeruginosa airway colonization in cystic fibrosis patients: 15 years experience

DEFF Research Database (Denmark)

Hansen, C.R.; Pressler, T.; Høiby, Niels

2008-01-01

BACKGROUND: Since 1989, CF-patients intermittently colonized with Pseudomonas aeruginosa have been treated with inhaled colistin and oral ciprofloxacin in the Copenhagen CF-centre. The study evaluates 15 years results of this treatment. METHODS: All isolates of P. aeruginosa from CF-patients inte......BACKGROUND: Since 1989, CF-patients intermittently colonized with Pseudomonas aeruginosa have been treated with inhaled colistin and oral ciprofloxacin in the Copenhagen CF-centre. The study evaluates 15 years results of this treatment. METHODS: All isolates of P. aeruginosa from CF......-patients intermittently colonized with P. aeruginosa from 1989 to 2003 were identified All anti-P. aeruginosa treatments were evaluated for antibiotics used, treatment duration, pseudomonas-free interval and development of chronic infection. All P. aeruginosa isolates were assessed for resistance and for non......-mucoid or mucoid phenotype. RESULTS: 146 CF-patients were included in the study (1106 patient-years). 99 patients had first ever isolate during the study period. Median observation time 7 years (0.1-14.9). 12 patients developed chronic infection. A Kaplan Meyer plot showed protection from chronic infection in up...

Structure analysis of the global metabolic regulator Crc from Pseudomonas aeruginosa.

Science.gov (United States)

Wei, Yong; Zhang, Heng; Gao, Zeng-Qiang; Xu, Jian-Hua; Liu, Quan-Sheng; Dong, Yu-Hui

2013-01-01

The global metabolic regulator catabolite repression control (Crc) has recently been found to modulate the susceptibility to antibiotics and virulence in the opportunistic pathogen Pseudomonas aeruginosa and been suggested as a nonlethal target for novel antimicrobials. In P. aeruginosa, Crc couples with the CA motifs from the small RNA CrcZ to form a post-transcriptional regulator system and is removed from the 5'-end of the target mRNAs. In this study, we first reported the crystal structure of Crc from P. aeruginosa refined to 2.20 Å. The structure showed that it consists of two halves with similar overall topology and there are 11 β strands surrounded by 13 helices, forming a four-layered α/β-sandwich. The circular dichroism spectroscopy revealed that it is thermostable in solution and shares similar characteristics to that in crystal. Comprehensive structural analysis and comparison with the homologies of Crc showed high similarity with several known nucleases and consequently may be classified into a member exodeoxyribonuclease III. However, it shows distinct substrate specificity (RNA as the preferred substrate) compared to these DNA endonucleases. Structural comparisons also revealed potential RNA recognition and binding region mainly consisting of five flexible loops. Our structure study provided the basis for the future application of Crc as a target to develop new antibiotics. Copyright © 2012 International Union of Biochemistry and Molecular Biology, Inc.

Carbapenem-resistant Pseudomonas aeruginosa: association with virulence genes and biofilm formation

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Iara Rossi Gonçalves

Full Text Available Abstract Pseudomonas aeruginosa is an opportunistic pathogen that causes frequently nosocomial infections, currently becoming more difficult to treat due to the various resistance mechanisms and different virulence factors. The purpose of this study was to determine the risk factors independently associated with the development of bacteremia by carbapenem-resistant P. aeruginosa, the frequency of virulence genes in metallo-β-lactamases producers and to evaluate their ability to produce biofilm. We conducted a case–control study in the Uberlândia Federal University – Hospital Clinic, Brazil. Polymerase Chain Reaction was performed for metallo-β-lactamases and virulence genes. Adhesion and biofilm assays were done by quantitative tests. Among the 157 strains analyzed, 73.9% were multidrug-resistant, 43.9% were resistant to carbapenems, 16.1% were phenotypically positive for metallo-β-lactamases, and of these, 10.7% were positive for blaSPM gene and 5.3% positive for blaVIM. The multivariable analysis showed that mechanical ventilation, enteral/nasogastric tubes, primary bacteremia with unknown focus, and inappropriate therapy were independent risk factors associated with bacteremia. All tested strains were characterized as strongly biofilm producers. A higher mortality was found among patients with bacteremia by carbapenem-resistant P. aeruginosa strains, associated independently with extrinsic risk factors, however it was not evident the association with the presence of virulence and metallo-β-lactamases genes.

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

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Adela M Luján

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

Regulation and function of versatile aerobic and anaerobic respiratory metabolism in Pseudomonas aeruginosa

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Hiroyuki eArai

2011-05-01

Full Text Available Pseudomonas aeruginosa is a ubiquitously distributed opportunistic pathogen that inhabits soil and water as well as animal-, human-, and plant-host-associated environments. The ubiquity would be attributed to its very versatile energy metabolism. P. aeruginosa has a highly branched respiratory chain terminated by multiple terminal oxidases and denitrification enzymes. Five terminal oxidases for aerobic respiration have been identified in the P. aeruginosa cells. Three of them, the cbb3-1 oxidase, the cbb3-2 oxidase, and the aa3 oxidase, are cytochrome c oxidases and the other two, the bo3 oxidase and the cyanide-insensitive oxidase, are quinol oxidases. Each oxidase has a specific affinity for oxygen, efficiency of energy coupling, and tolerance to various stresses such as cyanide and reactive nitrogen species. These terminal oxidases are used differentially according to the environmental conditions. P. aeruginosa also has a complete set of the denitrification enzymes that reduce nitrate to molecular nitrogen via nitrite, nitric oxide (NO, and nitrous oxide. These nitrogen oxides function as alternative electron acceptors and enable P. aeruginosa to grow under anaerobic conditions. One of the denitrification enzymes, NO reductase, is also expected to function for detoxification of NO produced by the host immune defense system. The control of the expression of these aerobic and anaerobic respiratory enzymes would contribute to the adaptation of P. aeruginosa to a wide range of environmental conditions including in the infected hosts. Characteristics of these respiratory enzymes and the regulatory system that controls the expression of the respiratory genes in the P. aeruginosa cells are overviewed in this article.

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

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Heidi Mulcahy

2011-10-01

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

Proteomic Response of Pseudomonas aeruginosa PAO1 Adhering to Solid Surfaces

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Morgan Guilbaud

2017-08-01

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

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

DEFF Research Database (Denmark)

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

2008-01-01

matrix, whereas nonmucoid variants were present mainly as dispersed cells. To obtain estimates of the growth rates of P. aeruginosa in CF lungs, we used quantitative FISH to indirectly measure growth rates of bacteria in sputum samples (reflecting the in vivo lung conditions). The concentration of r......The growth dynamics of bacterial pathogens within infected hosts are a fundamental but poorly understood feature of most infections. We have focused on the in situ distribution and growth characteristics of two prevailing and transmissible Pseudomonas aeruginosa clones that have caused chronic lung......RNA in bacteria isolated from sputa was measured and correlated with the rRNA contents of the same bacteria growing in vitro at defined rates. The results showed that most cells were actively growing with doubling times of between 100 and 200 min, with some growing even faster. Only a small stationary...

Cell death in Pseudomonas aeruginosa biofilm development

DEFF Research Database (Denmark)

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

2003-01-01

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

Pseudomonas predators: understanding and exploiting phage-host interactions.

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De Smet, Jeroen; Hendrix, Hanne; Blasdel, Bob G; Danis-Wlodarczyk, Katarzyna; Lavigne, Rob

2017-09-01

Species in the genus Pseudomonas thrive in a diverse set of ecological niches and include crucial pathogens, such as the human pathogen Pseudomonas aeruginosa and the plant pathogen Pseudomonas syringae. The bacteriophages that infect Pseudomonas spp. mirror the widespread and diverse nature of their hosts. Therefore, Pseudomonas spp. and their phages are an ideal system to study the molecular mechanisms that govern virus-host interactions. Furthermore, phages are principal catalysts of host evolution and diversity, which directly affects the ecological roles of environmental and pathogenic Pseudomonas spp. Understanding these interactions not only provides novel insights into phage biology but also advances the development of phage therapy, phage-derived antimicrobial strategies and innovative biotechnological tools that may be derived from phage-bacteria interactions.

Pseudomonas aeruginosa vesicles associate with and are internalized by human lung epithelial cells

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Kuehn Meta J

2009-02-01

Full Text Available Abstract Background Pseudomonas aeruginosa is the major pathogen associated with chronic and ultimately fatal lung infections in patients with cystic fibrosis (CF. To investigate how P. aeruginosa-derived vesicles may contribute to lung disease, we explored their ability to associate with human lung cells. Results Purified vesicles associated with lung cells and were internalized in a time- and dose-dependent manner. Vesicles from a CF isolate exhibited a 3- to 4-fold greater association with lung cells than vesicles from the lab strain PAO1. Vesicle internalization was temperature-dependent and was inhibited by hypertonic sucrose and cyclodextrins. Surface-bound vesicles rarely colocalized with clathrin. Internalized vesicles colocalized with the endoplasmic reticulum (ER marker, TRAPα, as well as with ER-localized pools of cholera toxin and transferrin. CF isolates of P. aeruginosa abundantly secrete PaAP (PA2939, an aminopeptidase that associates with the surface of vesicles. Vesicles from a PaAP knockout strain exhibited a 40% decrease in cell association. Likewise, vesicles from PAO1 overexpressing PaAP displayed a significant increase in cell association. Conclusion These data reveal that PaAP promotes the association of vesicles with lung cells. Taken together, these results suggest that P. aeruginosa vesicles can interact with and be internalized by lung epithelial cells and contribute to the inflammatory response during infection.

Development of a Pseudomonas aeruginosa Agmatine Biosensor

OpenAIRE

Gilbertsen, Adam; Williams, Bryan

2014-01-01

Agmatine, decarboxylated arginine, is an important intermediary in polyamine production for many prokaryotes, but serves higher functions in eukaryotes such as nitric oxide inhibition and roles in neurotransmission. Pseudomonas aeruginosa relies on the arginine decarboxylase and agmatine deiminase pathways to convert arginine into putrescine. One of the two known agmatine deiminase operons, aguBA, contains an agmatine sensitive TetR promoter controlled by AguR. We have discovered that this pr...

Characterization of Pseudomonas aeruginosa Chitinase, a Gradually Secreted Protein

NARCIS (Netherlands)

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

2001-01-01

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

2-Aminoacetophenone as a potential breath biomarker for Pseudomonas aeruginosa in the cystic fibrosis lung

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Laing Richard

2010-11-01

Full Text Available Abstract Background Pseudomonas aeruginosa infections are associated with progressive life threatening decline of lung function in cystic fibrosis sufferers. Growth of Ps. aeruginosa releases a "grape-like" odour that has been identified as the microbial volatile organic compound 2-aminoacetophenone (2-AA. Methods We investigated 2-AA for its specificity to Ps. aeruginosa and its suitability as a potential breath biomarker of colonisation or infection by Solid Phase Micro Extraction and Gas Chromatography-Mass Spectrometry (GC/MS. Results Cultures of 20 clinical strains of Ps. aeruginosa but not other respiratory pathogens had high concentrations of 2-AA in the head space of in vitro cultures when analysed by GC/MS. 2-AA was stable for 6 hours in deactivated glass sampling bulbs but was not stable in Tedlar® bags. Optimisation of GC/MS allowed detection levels of 2-AA to low pico mol/mol range in breath. The 2-AA was detected in a significantly higher proportion of subjects colonised with Ps. aeruginosa 15/16 (93.7% than both the healthy controls 5/17 (29% (p Ps. aeruginosa 4/13(30.7% (p Ps. aeruginosa in sputum and/or BALF was 93.8% (95% CI, 67-99 and 69.2% (95% CI, 38-89 respectively. The peak integration values for 2-AA analysis in the breath samples were significantly higher in Ps. aeruginosa colonised subjects (median 242, range 0-1243 than the healthy controls (median 0, range 0-161; p Ps. aeruginosa (median 0, range 0-287; p Conclusions Our results report 2-AA as a promising breath biomarker for the detection of Ps. aeruginosa infections in the cystic fibrosis lung.

Crystal structure of the flavoenzyme PA4991 from Pseudomonas aeruginosa

Energy Technology Data Exchange (ETDEWEB)

Jacewicz, Agata; Schnell, Robert; Lindqvist, Ylva; Schneider, Gunter, E-mail: gunter.schneider@ki.se [Karolinska Institutet, S-171 77 Stockholm (Sweden)

2016-01-22

PA4991 is a FAD-dependent oxidoreductase from the pathogen P. aeruginosa that is essential for virulence and survival in the infected host. The structure of this enzyme, determined to 2.4 Å resolution, reveals that PA4991 belongs to the GR{sub 2} family of flavoenzymes. The locus PA4991 in Pseudomonas aeruginosa encodes an open reading frame that has been identified as essential for the virulence and/or survival of this pathogenic organism in the infected host. Here, it is shown that this gene encodes a monomeric FAD-binding protein of molecular mass 42.2 kDa. The structure of PA4991 was determined by a combination of molecular replacement using a search model generated with Rosetta and phase improvement by a low-occupancy heavy-metal derivative. PA4991 belongs to the GR{sub 2} family of FAD-dependent oxidoreductases, comprising an FAD-binding domain typical of the glutathione reductase family and a second domain dominated by an eight-stranded mixed β-sheet. Most of the protein–FAD interactions are via the FAD-binding domain, but the isoalloxazine ring is located at the domain interface and interacts with residues from both domains. A comparison with the structurally related glycine oxidase and glycerol-3-phosphate dehydrogenase shows that in spite of very low amino-acid sequence identity (<18%) several active-site residues involved in substrate binding in these enzymes are conserved in PA4991. However, enzymatic assays show that PA4991 does not display amino-acid oxidase or glycerol-3-phosphate dehydrogenase activities, suggesting that it requires different substrates for activity.

Crystal structure of the flavoenzyme PA4991 from Pseudomonas aeruginosa

International Nuclear Information System (INIS)

Jacewicz, Agata; Schnell, Robert; Lindqvist, Ylva; Schneider, Gunter

2016-01-01

PA4991 is a FAD-dependent oxidoreductase from the pathogen P. aeruginosa that is essential for virulence and survival in the infected host. The structure of this enzyme, determined to 2.4 Å resolution, reveals that PA4991 belongs to the GR 2 family of flavoenzymes. The locus PA4991 in Pseudomonas aeruginosa encodes an open reading frame that has been identified as essential for the virulence and/or survival of this pathogenic organism in the infected host. Here, it is shown that this gene encodes a monomeric FAD-binding protein of molecular mass 42.2 kDa. The structure of PA4991 was determined by a combination of molecular replacement using a search model generated with Rosetta and phase improvement by a low-occupancy heavy-metal derivative. PA4991 belongs to the GR 2 family of FAD-dependent oxidoreductases, comprising an FAD-binding domain typical of the glutathione reductase family and a second domain dominated by an eight-stranded mixed β-sheet. Most of the protein–FAD interactions are via the FAD-binding domain, but the isoalloxazine ring is located at the domain interface and interacts with residues from both domains. A comparison with the structurally related glycine oxidase and glycerol-3-phosphate dehydrogenase shows that in spite of very low amino-acid sequence identity (<18%) several active-site residues involved in substrate binding in these enzymes are conserved in PA4991. However, enzymatic assays show that PA4991 does not display amino-acid oxidase or glycerol-3-phosphate dehydrogenase activities, suggesting that it requires different substrates for activity

Decrease of Pseudomonas aeruginosa biofilm formation by food waste materials

Czech Academy of Sciences Publication Activity Database

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

2016-01-01

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

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

NARCIS (Netherlands)

Fong, Stephanie A.; Drilling, Amanda; Morales, Sandra; Cornet, Marjolein E.; Woodworth, Bradford A.; Fokkens, Wytske J.; Psaltis, Alkis J.; Vreugde, Sarah; Wormald, Peter-John

2017-01-01

Introduction:Pseudomonas aeruginosa infections are prevalent amongst chronic rhinosinusitis (CRS) sufferers. Many P. aeruginosa strains form biofilms, leading to treatment failure. Lytic bacteriophages (phages) are viruses that infect, replicate within, and lyse bacteria, causing bacterial death.

Antiplasmid Potential of Kalanchoe blossfeldiana Against Multidrug ResistancePseudomonas aeruginosa

OpenAIRE

ZirakFaqe Ahmed Abdulrahman

2014-01-01

This study concerned with the isolation of Pseudomonas aeruginosa from various clinical cases in human which include (burn, wound and urine) that admitted to Emergency hospital and internal lab of teaching hospital in Erbil city. Forty isolates of P. aeruginosa from out of 120 samples were identified by using cultured, morphological and biochemical tests in addition to vitek machine. According to the resistance of the isolates to these antibiotics they showed variation in their resistance; th...

Interference of Pseudomonas aeruginosa signalling and biofilm formation for infection control

DEFF Research Database (Denmark)

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

2010-01-01

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

Functional study of elafin cleaved by Pseudomonas aeruginosa metalloproteinases.

LENUS (Irish Health Repository)

Guyot, Nicolas

2010-06-01

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

Heterogeneous production of proteases from Brazilian clinical isolates of Pseudomonas aeruginosa.

Science.gov (United States)

Galdino, Anna Clara M; Viganor, Lívia; Ziccardi, Mariangela; Nunes, Ana Paula F; Dos Santos, Kátia R N; Branquinha, Marta H; Santos, André L S

2017-12-01

Pseudomonas aeruginosa is an important human pathogen that causes severe infections in a wide range of immunosuppressed patients. Herein, we evaluated the proteolytic profiles of 96 Brazilian clinical isolates of P. aeruginosa recovered from diverse anatomical sites. Cell-associated and extracellular proteases were evidenced by gelatin-SDS-PAGE and by the cleavage of soluble gelatin. Elastase was measured by using the peptide substrate N-succinyl-Ala-Ala-Ala-p-nitroanilide. The prevalence of elastase genes (lasA and lasB) was evaluated by PCR. Bacterial extracts were initially applied on gelatin-SDS-PAGE and the results revealed four distinct zymographic profiles as follows: profile I (composed by bands of 145, 118 and 50kDa), profile II (118 and 50kDa), profile III (145kDa) and profile IV (118kDa). All the proteolytic enzymes were inhibited by EDTA, identifying them as metalloproteases. The profile I was the most detected in both cellular (79.2%) and extracellular (84.4%) extracts. Overall, gelatinase and elastase activities measured in the spent culture media were significantly higher (around 2-fold) compared to the cellular extracts and the production level varied according to the site of bacterial isolation. For instance, tracheal secretion isolates produced elevated amount of gelatinase and elastase measured in both cellular and extracellular extracts. The prevalence of elastase genes revealed that 100% isolates were lasB-positive and 85.42% lasA-positive. Some positive/negative correlations were showed concerning the production of gelatinase, elastase, isolation site and antimicrobial susceptibility. The protease production was highly heterogeneous in Brazilian clinical isolates of P. aeruginosa, which corroborates the genomic/metabolic versatility of this pathogen. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Antibacterial activity of a newly developed peptide-modified lysin against Acinetobacter baumannii and Pseudomonas aeruginosa

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Hang eYang

2015-12-01

Full Text Available The global emergence of multidrug-resistant (MDR bacteria is a growing threat to public health worldwide. Natural bacteriophage lysins are promising alternatives in the treatment of infections caused by Gram-positive pathogens, but not Gram-negative ones, like Acinetobacter baumannii and Pseudomonas aeruginosa, due to the barriers posed by their outer membranes. Recently, modifying a natural lysin with an antimicrobial peptide was found able to break the barriers, and to kill Gram-negative pathogens. Herein, a new peptide-modified lysin (PlyA was constructed by fusing the cecropin A peptide residues 1–8 (KWKLFKKI with the OBPgp279 lysin and its antibacterial activity was studied. PlyA showed good and broad antibacterial activities against logarithmic phase A. baumannii and P. aeruginosa, but much reduced activities against the cells in stationary phase. Addition of outer membrane permeabilizers (EDTA and citric acid could enhance the antibacterial activity of PlyA against stationary phase cells. Finally, no antibacterial activity of PlyA could be observed in some bio-matrices, such as culture media, milk, and sera. In conclusion, we reported here a novel peptide-modified lysin with significant antibacterial activity against both logarithmic (without OMPs and stationary phase (with OMPs A. baumannii and P. aeruginosa cells in buffer, but further optimization is needed to achieve broad activity in diverse bio-matrices.

Pseudomonas aeruginosa ventilator-associated pneumonia management

Science.gov (United States)

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

Extracellular DNA Shields against Aminoglycosides in Pseudomonas aeruginosa Biofilms

DEFF Research Database (Denmark)

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

2013-01-01

Within recent years, it has been established that extracellular DNA is a key constituent of the matrix of microbial biofilms. In addition, it has recently been demonstrated that DNA binds positively charged antimicrobials such as aminoglycosides and antimicrobial peptides. In the present study, we...... provide evidence that extracellular DNA shields against aminoglycosides in Pseudomonas aeruginosa biofilms. We show that exogenously supplemented DNA integrates into P. aeruginosa biofilms and increases their tolerance toward aminoglycosides. We provide evidence that biofilms formed by a DNA release......-deficient P. aeruginosa quorum-sensing mutant are more susceptible to aminoglycoside treatment than wild-type biofilms but become rescued from the detrimental action of aminoglycosides upon supplementation with exogenous DNA. Furthermore, we demonstrate that exposure to lysed polymorphonuclear leukocytes...

Interaction of antibacterial compounds with RND efflux pumps in Pseudomonas aeruginosa

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Juerg eDreier

2015-07-01

Full Text Available Pseudomonas aeruginosa infections are becoming increasingly difficult to treat due to intrinsic antibiotic resistance and the propensity of this pathogen to accumulate diverse resistance mechanisms. Hyperexpression of efflux pumps of the Resistance-Nodulation-Division-type multidrug efflux pumps (e.g. MexAB-OprM, chromosomally encoded by mexAB-oprM, mexCD-oprJ, mexEF-oprN, and mexXY (-oprA is often detected in clinical isolates and contributes to worrying multi-drug resistance phenotypes.Not all antibiotics are affected to the same extent by the aforementioned RND efflux pumps. The impact of efflux on antibiotic activity varies not only between different classes of antibiotics but also between members of the same family of antibiotics. Subtle differences in physicochemical features of compound-pump and compound-solvent interactions largely determine how compounds are affected by efflux activity.The combination of different high-resolution techniques helps to gain insight into the functioning of these molecular machineries. This review discusses substrate recognition patterns based on experimental evidence and computer simulations with a focus on MexB, the pump subunit of the main RND transporter in P. aeruginosa.

Draft Genome Sequences of Pseudomonas aeruginosa B3 Strains Isolated from a Cystic Fibrosis Patient Undergoing Antibiotic Chemotherapy

DEFF Research Database (Denmark)

Marvig, Rasmus Lykke; Jochumsen, Nicholas; Johansen, Helle Krogh

2013-01-01

Pseudomonas aeruginosa frequently establishes chronic infections in the airways of patients suffering from cystic fibrosis (CF). Here, we report the draft genome sequences of four P. aeruginosa B3 strains isolated from a chronically infected CF patient undergoing antibiotic chemotherapy.......Pseudomonas aeruginosa frequently establishes chronic infections in the airways of patients suffering from cystic fibrosis (CF). Here, we report the draft genome sequences of four P. aeruginosa B3 strains isolated from a chronically infected CF patient undergoing antibiotic chemotherapy....

Occurrence of Ambler Class B Metallo-β-Lactamase Gene in Imipenem-Resistant Pseudomonas Aeruginosa Strains Isolated from Clinical Samples

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Zeynab Golshani

2014-02-01

Full Text Available Background: 5TMetallo-β-lactamase (MBLs can hydrolyze a broad spectrum of beta-lactams, including penicillins, cephalosporins, and carbapenems. Genes encoding these enzymes are located on the plasmid that can easily be transferred to other bacteria. The aim of this study was to isolate and identify the Pseudomonas aeruginosa strains encoding VIM1 gene, in clinical samples, using the PCR technique. Materials and Methods: During a 4 month period, 100 strains of Pseudomonas aeruginosa from clinical specimens were collected. Standard tests were performed to identify strains of Pseudomonas aeruginosa. Resistance to antibiotics was examined and then the PCR was used to detect VIM1gene. Results:In this study, the highest rates of resistance to antibiotics, amikacin and cefotaxime was observed (65% and 62%, the lowest resistance to antibiotics piperacillin (48% and imipenem and cefepime with 55% resistance was reported. DDST method was performed for 37 strains for the MBl detection. Among the 37 isolate, 30 strains were MBL-producing with imipenem-EDTA method. Twelve strains (18% were carriers of VIM1 gene using the PCR method. Conclusion: In the present study, the prevalence of strains producing MBL genes in strains of hospitals is a growing trend; correct prescription of medications can prevent the spread of resistant pathogens. It is suggested that molecular methods for rapid detection of resistance genes can be used to prevent the spread of this genes.

Production of bio surfactants (Rhamnolipids) by pseudomonas aeruginosa isolated from colombian sludges

International Nuclear Information System (INIS)

Pimienta, A.L; Diaz M, M. P; Carvajal S, F.G; Grosso V, J.L.

1997-01-01

The bio surfactant production by strains of Pseudomonas aeruginosa isolated from Colombian hydrocarbon contaminated sludge has been determined. The methodology included the isolation of microorganisms, standardization of batch culture conditions for good surfactant production and characterization of the produced rhamnolipid. Several carbon sources were evaluated with regard to the growth and production curves. The stability of the rhamnolipid was also determined under variable conditions of pH, temperature and salt concentration. The strain Pseudomonas aeruginosa BS 3 showed bio surfactant production capabilities of rhamnolipid resulting in concentrations up to 2 g-dm with surface tensions of 30 - 32 mN-m in batch cultures with commercial nutrients

High-Throughput Genetic Screen Reveals that Early Attachment and Biofilm Formation Are Necessary for Full Pyoverdine Production by Pseudomonas aeruginosa

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Donghoon Kang

2017-09-01

Full Text Available Pseudomonas aeruginosa is a re-emerging, multidrug-resistant, opportunistic pathogen that threatens the lives of immunocompromised patients, patients with cystic fibrosis, and those in critical care units. One of the most important virulence factors in this pathogen is the siderophore pyoverdine. Pyoverdine serves several critical roles during infection. Due to its extremely high affinity for ferric iron, pyoverdine gives the pathogen a significant advantage over the host in their competition for iron. In addition, pyoverdine can regulate the production of multiple bacterial virulence factors and perturb host mitochondrial homeostasis. Inhibition of pyoverdine biosynthesis decreases P. aeruginosa pathogenicity in multiple host models. To better understand the regulation of pyoverdine production, we developed a high-throughput genetic screen that uses the innate fluorescence of pyoverdine to identify genes necessary for its biosynthesis. A substantial number of hits showing severe impairment of pyoverdine production were in genes responsible for early attachment and biofilm formation. In addition to genetic disruption of biofilm, both physical and chemical perturbations also attenuated pyoverdine production. This regulatory relationship between pyoverdine and biofilm is particularly significant in the context of P. aeruginosa multidrug resistance, where the formation of biofilm is a key mechanism preventing access to antimicrobials and the immune system. Furthermore, we demonstrate that the biofilm inhibitor 2-amino-5,6-dimethylbenzimidazole effectively attenuates pyoverdine production and rescues Caenorhabditis elegans from P. aeruginosa-mediated pathogenesis. Our findings suggest that targeting biofilm formation in P. aeruginosa infections may have multiple therapeutic benefits and that employing an unbiased, systems biology-based approach may be useful for understanding the regulation of specific virulence factors and identifying novel anti

Draft Genome Sequence Analysis of a Pseudomonas putida W15Oct28 Strain with Antagonistic Activity to Gram-Positive and Pseudomonas sp. Pathogens

Science.gov (United States)

Ye, Lumeng; Hildebrand, Falk; Dingemans, Jozef; Ballet, Steven; Laus, George; Matthijs, Sandra; Berendsen, Roeland; Cornelis, Pierre

2014-01-01

Pseudomonas putida is a member of the fluorescent pseudomonads known to produce the yellow-green fluorescent pyoverdine siderophore. P. putida W15Oct28, isolated from a stream in Brussels, was found to produce compound(s) with antimicrobial activity against the opportunistic pathogens Staphylococcus aureus, Pseudomonas aeruginosa, and the plant pathogen Pseudomonas syringae, an unusual characteristic for P. putida. The active compound production only occurred in media with low iron content and without organic nitrogen sources. Transposon mutants which lost their antimicrobial activity had the majority of insertions in genes involved in the biosynthesis of pyoverdine, although purified pyoverdine was not responsible for the antagonism. Separation of compounds present in culture supernatants revealed the presence of two fractions containing highly hydrophobic molecules active against P. aeruginosa. Analysis of the draft genome confirmed the presence of putisolvin biosynthesis genes and the corresponding lipopeptides were found to contribute to the antimicrobial activity. One cluster of ten genes was detected, comprising a NAD-dependent epimerase, an acetylornithine aminotransferase, an acyl CoA dehydrogenase, a short chain dehydrogenase, a fatty acid desaturase and three genes for a RND efflux pump. P. putida W15Oct28 genome also contains 56 genes encoding TonB-dependent receptors, conferring a high capacity to utilize pyoverdines from other pseudomonads. One unique feature of W15Oct28 is also the presence of different secretion systems including a full set of genes for type IV secretion, and several genes for type VI secretion and their VgrG effectors. PMID:25369289

Structure of a putative acetyltransferase (PA1377) from Pseudomonas aeruginosa

International Nuclear Information System (INIS)

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

2008-01-01

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

[Epidemiological profile and antibiotic resistance of Pseudomonas aeruginosa isolates in burn and traumatology center in Tunisia over a three-year period].

Science.gov (United States)

Zoghlami, Ayoub; Kanzari, Lamia; Boukadida, Jalel; Messadi, Amen Allah; Ghanem, Abdelraouef

2012-11-01

Pseudomonas aeruginosa is a known opportunistic pathogen frequently causing serious infections in burned patients. To analyze the epidemiological profile of Pseudomonas aeruginosa isolated in a Tunisian burn unit. During a 3-year period (from 01 July 2008 to 30 June 2011), 544 non repetitive strains of P. aeruginosa were isolated from burn patients. Susceptibility to antibiotics was assessed according to CA-SFM guidelines. Serotypes were identified by slide agglutination test using P.aeruginosa O antisera (Biorad). Producing carbapenemase was analyzed for 202 imipenem resistant isolates by EDTA test. Susceptibility testing data were stored in a laboratory data base using whonet 5.3 software. The most frequent sites of isolation were cutaneous infections and blood cultures (83.4%). The percentages of resistant isolates were as follows: ceftazidime: 34%; imipenem: 37.1%, ciprofloxacin: 27.1% and amikacin: 29.6%. The most prevalent serotypes were: 011(51%), 06(17%), 03 (8%), 04(12%), 012(5%). Among the 202 imipenem resistant strains, 58% expressed a metallocarbapenemase. All theses strains were resistant to all tested antibiotics except colistin and belonged to the serotype O11. The dissemination of carbapenemases strains must be contained by implementation of timely identification, strict isolation methods and better hygienic procedures.

Attenuation of quorum-sensing-dependent virulence factors and biofilm formation by medicinal plants against antibiotic resistant Pseudomonas aeruginosa

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P. Sankar Ganesh

2018-01-01

Full Text Available Pseudomonas aeruginosa use small signaling molecules such as acyl homoserine lactones (AHLs, which play an important role in release virulence factors and toxin for further establishment of host infection. Thus, involving with the QS system would provide alternative ways of preventing the pathogenicity. In the present study, totally six medicinal plants (Terminalia bellerica, Celastrus paniculatus, Kingiodendron pinnatum, Schleichera oleosa, Melastoma malabathricum, Garcinia gummi-gutta were screened for anti-QS activity using biomonitor strain of Chromobacterium violaceum CV12472. The primary screening of antimicrobial activity of all the plant extracts have inhibited the growth of tested bacterial species. Of these at the sub-minimum inhibitory concentration the methanol extract of T. bellerica (0.0625–0.5 mg/ml has significantly inhibited violacein production (20.07–66.22% in C. violaceum (CV12472. Consequently, the extract of T. bellerica has reduced the production of pyocyanin, exopolysaccharide and biofilm formation in P. aeruginosa strains. Fluorescence and scanning electron microscopy analysis confirmed the reduction of biofilm formation in P. aeruginosa strains when treated with T. bellerica. GC–MS analysis showed the active compounds inhibited the production of virulence factors of P. aeruginosa. The results suggest the possible use of this T. bellerica as an anti-QS and anti-biofilm agent to control Pseudomonas infection. Interference of QS provides an important means for the inhibition of bacterial virulence and thus aids in treatment strategies.

Virus-Induced Type I Interferon Deteriorates Control of Systemic Pseudomonas Aeruginosa Infection

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Katja Merches

2015-07-01

Full Text Available Background: Type I interferon (IFN-I predisposes to bacterial superinfections, an important problem during viral infection or treatment with interferon-alpha (IFN-α. IFN-I-induced neutropenia is one reason for the impaired bacterial control; however there is evidence that more frequent bacterial infections during IFN-α-treatment occur independently of neutropenia. Methods: We analyzed in a mouse model, whether Pseudomonas aeruginosa control is influenced by co-infection with the lymphocytic choriomeningitis virus (LCMV. Bacterial titers, numbers of neutrophils and the gene-expression of liver-lysozyme-2 were determined during a 24 hours systemic infection with P. aeruginosa in wild-type and Ifnar-/- mice under the influence of LCMV or poly(I:C. Results: Virus-induced IFN-I impaired the control of Pseudomonas aeruginosa. This was associated with neutropenia and loss of lysozyme-2-expression in the liver, which had captured P. aeruginosa. A lower release of IFN-I by poly(I:C-injection also impaired the bacterial control in the liver and reduced the expression of liver-lysozyme-2. Low concentration of IFN-I after infection with a virulent strain of P. aeruginosa alone impaired the bacterial control and reduced lysozyme-2-expression in the liver as well. Conclusion: We found that during systemic infection with P. aeruginosa Kupffer cells quickly controlled the bacteria in cooperation with neutrophils. Upon LCMV-infection this cooperation was disturbed.

Evaluation of phytochemicals from medicinal plants of Myrtaceae family on virulence factor production by Pseudomonas aeruginosa.

Science.gov (United States)

Musthafa, Khadar Syed; Sianglum, Wipawadee; Saising, Jongkon; Lethongkam, Sakkarin; Voravuthikunchai, Supayang Piyawan

2017-05-01

Virulence factors regulated by quorum sensing (QS) play a critical role in the pathogenesis of an opportunistic human pathogen, Pseudomonas aeruginosa in causing infections to the host. Hence, in the present work, the anti-virulence potential of the medicinal plant extracts and their derived phytochemicals from Myrtaceae family was evaluated against P. aeruginosa. In the preliminary screening of the tested medicinal plant extracts, Syzygium jambos and Syzygium antisepticum demonstrated a maximum inhibition in QS-dependent violacein pigment production by Chromobacterium violaceum DMST 21761. These extracts demonstrated an inhibitory activity over a virulence factor, pyoverdin, production by P. aeruginosa ATCC 27853. Gas chromatography-mass spectrometric (GC-MS) analysis revealed the presence of 23 and 12 phytochemicals from the extracts of S. jambos and S. antisepticum respectively. Three top-ranking phytochemicals, including phytol, ethyl linoleate and methyl linolenate, selected on the basis of docking score in molecular docking studies lowered virulence factors such as pyoverdin production, protease and haemolytic activities of P. aeruginosa to a significant level. In addition, the phytochemicals reduced rhamnolipid production by the organism. The work demonstrated an importance of plant-derived compounds as anti-virulence drugs to conquer P. aeruginosa virulence towards the host. © 2017 APMIS. Published by John Wiley & Sons Ltd.

Secretory IgA as a diagnostic tool for Pseudomonas aeruginosa respiratory colonization

DEFF Research Database (Denmark)

Aanaes, Kasper; Johansen, Helle Krogh; Poulsen, Steen Seier

2012-01-01

BACKGROUND: Pseudomonas aeruginosa sinusitis may be the focus for intermittent lung colonization in patients with cystic fibrosis (CF). The sinusitis may induce elevated IgA levels in nasal secretion and saliva against P. aeruginosa. METHODS: 120 CF patients chronically infected, intermittently...... colonized or without P. aeruginosa in the lungs participated in this cross-sectional study. IgA and IgG against P. aeruginosa sonicate and alginate were measured in nasal secretions, saliva, and in serum by ELISA. RESULTS: The intermittently colonized patients had significantly higher IgA levels in nasal...... secretions and saliva than those without P. aeruginosa in the lungs, indicating that P. aeruginosa sinusitis may precede intermittent colonization and chronic infection of the lungs. CONCLUSIONS: Specific IgA against P. aeruginosa in nasal secretions and saliva can contribute to differentiation between...

Metabolite Profiling to Characterize Disease-related Bacteria GLUCONATE EXCRETION BY PSEUDOMONAS AERUGINOSA MUTANTS AND CLINICAL ISOLATES FROM CYSTIC FIBROSIS PATIENTS

OpenAIRE

Behrends, V; Bell, TJ; Liebeke, M; Cordes-Blauert, A; Ashraf, SN; Nair, C; Zlosnik, JEA; Williams, HD; Bundy, JG

2013-01-01

Metabolic footprinting of supernatants has been proposed as a tool for assigning gene function. We used NMR spectroscopy to measure the exometabolome of 86 single-gene transposon insertion mutant strains (mutants from central carbon metabolism and regulatory mutants) of the opportunistic pathogen Pseudomonas aeruginosa, grown on a medium designed to represent the nutritional content of cystic fibrosis sputum. Functionally related genes had similar metabolic profiles. E.g. for two-component sy...

Discovery of an inhibitor of the production of the Pseudomonas aeruginosa virulence factor pyocyanin in wild-type cells

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Bernardas Morkunas

2016-07-01

Full Text Available Pyocyanin is a small molecule produced by Pseudomonas aeruginosa that plays a crucial role in the pathogenesis of infections by this notorious opportunistic pathogen. The inhibition of pyocyanin production has been identified as an attractive antivirulence strategy for the treatment of P. aeruginosa infections. Herein, we report the discovery of an inhibitor of pyocyanin production in cultures of wild-type P. aeruginosa which is based around a 4-alkylquinolin-2(1H-one scaffold. To the best of our knowledge, this is the first reported example of pyocyanin inhibition by a compound based around this molecular framework. The compound may therefore be representative of a new structural sub-class of pyocyanin inhibitors, which could potentially be exploited in in a therapeutic context for the development of critically needed new antipseudomonal agents. In this context, the use of wild-type cells in this study is notable, since the data obtained are of direct relevance to native situations. The compound could also be of value in better elucidating the role of pyocyanin in P. aeruginosa infections. Evidence suggests that the active compound reduces the level of pyocyanin production by inhibiting the cell–cell signalling mechanism known as quorum sensing. This could have interesting implications; quorum sensing regulates a range of additional elements associated with the pathogenicity of P. aeruginosa and there is a wide range of other potential applications where the inhibition of quorum sensing is desirable.

Antivirulence activity of azithromycin in Pseudomonas aeruginosa

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Francesco eImperi

2014-04-01

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

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

DEFF Research Database (Denmark)

Høiby, Niels

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 sug...... 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....

Antibacterial Activity of Desert Truffles from Saudi Arabia Against Staphylococcus aureus and Pseudomonas aeruginosa.

Science.gov (United States)

Schillaci, Domenico; Cusimano, Maria Grazia; Cascioferro, Stella Maria; Di Stefano, Vita; Arizza, Vincenzo; Chiaramonte, Marco; Inguglia, Luigi; Bawadekji, Abdulhakim; Davino, Salvatore; Gargano, Maria Letizia; Venturella, Giuseppe

2017-01-01

Medicinal mushrooms represent an unlimited source of polysaccharides with nutritional, antitumoral, antibacterial, and immune-stimulating properties. Traditional studies of epigeous higher Basidiomycetes have recently been joined by studies of hypogeous fungi and, in particular, of so-called desert truffles. With the aim to obtain novel agents against bacteria of clinical importance, we focused on the edible desert truffle mushrooms Tirmania pinoyi, Terfezia claveryi, and Picoa juniperi as sources of new antimicrobial agents. In particular, we investigated the in vitro antibacterial activity of acid-soluble protein extracts (aqueous extracts) of these 3 species against the Gram-positive human pathogenic reference strain Staphylococcus aureus ATCC 29213 and the Gram-negative strain Pseudomonas aeruginosa ATCC 15442. The acid-soluble protein extracts of T. pinoyi and T. claveryi showed minimum inhibitory concentrations of 50 μg/mL against tested pathogens. We believe that such preliminary results are promising to obtain a valuable antibiotic alternative to fight antibiotic-resistant pathogens.

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

African Journals Online (AJOL)

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

Phenotypic characterization and colistin susceptibilities of carbapenem-resistant of Pseudomonas aeruginosa and Acinetobacter spp.

Science.gov (United States)

Mohanty, Srujana; Maurya, Vijeta; Gaind, Rajni; Deb, Monorama

2013-11-15

Pseudomonas aeruginosa and Acinetobcter spp. are important nosocomial pathogens and carbapenem resistance is an emerging threat. Therapeutic options for infections with these isolates include colistin. This study was conducted to determine the prevalence of carbapenem resistance in P. aeruginosa and Acinetobacter spp. bloodstream isolates, phenotypically characterize the resistance mechanisms and evaluate the in vitro activity of colistin. Consecutive 145 (95 P.aeruginosa and 50 Acinetobacter spp.) non-repeat isolates were included. Antibiotic susceptibility testing was performed per CLSI guidelines. MIC for carbapenems and colistin was performed using Etest. Isolates showing reduced susceptibility or resistance to the carbapenems were tested for metallo-β-lactamase (MBL) production using imipenem-EDTA combined disk and MBL Etest. Carbapenem resistance was observed in 40% P. aeruginosa and 66.0% Acinetobacter spp. Carbapenem-resistant (CA-R) isolates were significantly (p carbapenem-susceptible isolates. Approximately half of the CA-R strains were multidrug-resistant, and 3.1-5.5% were resistant to all antibiotics tested. MBL was found in 76.3% and 69.7% of the P. aeruginosa and Acinetobacter spp., respectively. Colistin resistance was observed in three (6.0%) Acinetobacter isolates and eight (8.4%) P. aeruginosa. MIC50 for carbapenems were two to four times higher for MBL-positive compared to MBL-negative isolates, but no difference was seen in MIC for colistin. Carbapenem resistance was observed to be mediated by MBL in a considerable number of isolates. Colistin is an alternative for infections caused by CA-R isolates; however, MIC testing should be performed whenever clinical use of colistin is considered.

Emergence of Imipenem-Resistant Pseudomonas aeruginosa Clinical Isolates from Egypt Coharboring VIM and IMP Carbapenemases.

Science.gov (United States)

El-Domany, Ramadan Ahmed; Emara, Mohamed; El-Magd, Mohammed A; Moustafa, Walaa H; Abdeltwab, Nesma M

2017-09-01

Pseudomonas aeruginosa is an important human pathogen and the leading cause of nosocomial infections. P. aeruginosa is characterized by massive intrinsic resistance to a multiple classes of antibiotics with carbapenems being the most potent inhibitor of P. aeruginosa and considered the first choice for its treatment. Therefore, it is crucial to investigate novel mechanisms of resistance of P. aeruginosa to carbapenems for achieving successful therapy. A total of 114 P. aeruginosa isolates from two university hospitals in Egypt were recruited in this study. Antimicrobial susceptibility testing revealed that 50 isolates (43.8%) exhibited multidrug-resistant (MDR) phenotype, of them 14 isolates (12.2%) were imipenem (IPM)-resistant. Of these 14 isolates, 13 isolates (11.4%) exhibited the metallo-β-lactamase (MBL) phenotype. MBLs encoding genes, VIM and IMP, were identified by PCR. PCR results revealed that four isolates harbored the VIM gene alone, one isolate harbored IMP gene alone, and four isolates harbored both genes. The correct size of PCR products of VIM and IMP genes (390 and 188 bp, respectively) were sequenced to confirm results of PCR and to look for any possible polymorphism among MBL genes of tested isolates. Data analysis of these sequences showed 100% identity of nucleotide sequences of MBL genes among tested Egyptian patients. To our knowledge, this is the first report of IMP carbapenemase-encoding gene in Africa and the first detection of the emergence of P. aeruginosa coproducing VIM and IMP genes in Egypt.

Pseudomonas aeruginosa Population Structure Revisited

Science.gov (United States)

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

Plant flavones enhance antimicrobial activity of respiratory epithelial cell secretions against Pseudomonas aeruginosa.

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Benjamin M Hariri

Full Text Available Flavones are a class of natural plant secondary metabolites that have anti-inflammatory and anti-bacterial effects. Some flavones also activate the T2R14 bitter taste receptor, which is expressed in motile cilia of the sinonasal epithelium and activates innate immune nitric oxide (NO production. Flavones may thus be potential therapeutics for respiratory infections. Our objective was to examine the anti-microbial effects of flavones on the common sinonasal pathogens Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa, evaluating both planktonic and biofilm growth. Flavones had only very low-level antibacterial activity alone. They did not reduce biofilm formation, but did reduce production of the important P. aeruginosa inflammatory mediator and ciliotoxin pyocyanin. However, flavones exhibited synergy against P. aeruginosa in the presence of antibiotics or recombinant human lysozyme. They also enhanced the efficacy of antimicrobials secreted by cultured and primary human airway cells grown at air-liquid interface. This suggests that flavones may have anti-gram-negative potential as topical therapeutics when combined with antibiotics or in the context of innate antimicrobials secreted by the respiratory or other epithelia. This may have an additive effect when combined with T2R14-activated NO production. Additional studies are necessary to understand which flavone compounds or mixtures are the most efficacious.

Pseudomonas aeruginosa Transmigrates at Epithelial Cell-Cell Junctions, Exploiting Sites of Cell Division and Senescent Cell Extrusion.

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Guillaume Golovkine

2016-01-01

Full Text Available To achieve systemic infection, bacterial pathogens must overcome the critical and challenging step of transmigration across epithelial barriers. This is particularly true for opportunistic pathogens such as Pseudomonas aeruginosa, an agent which causes nosocomial infections. Despite extensive study, details on the mechanisms used by this bacterium to transmigrate across epithelial tissues, as well as the entry sites it uses, remain speculative. Here, using real-time microscopy and a model epithelial barrier, we show that P. aeruginosa employs a paracellular transmigration route, taking advantage of altered cell-cell junctions at sites of cell division or when senescent cells are expelled from the cell layer. Once a bacterium transmigrates, it is followed by a cohort of bacteria using the same entry point. The basal compartment is then invaded radially from the initial penetration site. Effective transmigration and propagation require type 4 pili, the type 3 secretion system (T3SS and a flagellum, although flagellum-deficient bacteria can occasionally invade the basal compartment from wounded areas. In the basal compartment, the bacteria inject the T3SS toxins into host cells, disrupting the cytoskeleton and focal contacts to allow their progression under the cells. Thus, P. aeruginosa exploits intrinsic host cell processes to breach the epithelium and invade the subcellular compartment.

Outbreak of Pseudomonas aeruginosa bacteraemia in a haematology department

DEFF Research Database (Denmark)

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

2015-01-01

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

Blue light enhances the antimicrobial activity of honey against Pseudomonas aeruginosa

Science.gov (United States)

Orlandi, Viviana Teresa; Bolognese, Fabrizio; Barbieri, Paola

2018-02-01

Pseudomonas aeruginosa may be isolated from skin wounds of burn patients, bedsore and diabetic ulcers. The healing of wounds is often impaired by the intrinsic antibiotic resistance, the tolerance to many antimicrobials and the ability to form biofilm of this opportunistic pathogen. Finding new topical treatments to combine with antibiotics is thus essential. Among natural products, the antimicrobial properties of honeys have been known for millennia. In this study honey and visible light have been combined to control the growth of P. aeruginosa PAO1. The irradiation by a broad spectrum light source of bacteria inoculated onto 2 % w/v fir and forest honeydew (HD) honeys caused a killing effect that the honeys alone or the light alone did not show. This antimicrobial activity was light energy-dose and honey-concentration dependent. Among the tested honeys, the fir and forest HD honeys were the most efficient ones. In particular, the irradiation by blue LED (λmax = 466 nm) yielded good rates of killing, that were significantly higher in comparison to irradiation alone and honey alone. Interestingly, a similar effect was obtained by plating bacteria on blue LED pre-irradiated HD honeys. The combined use of honey and blue light was also successful in inhibiting the biofilm formation of P. aeruginosa. The blue LED irradiation of PAO1 administered with 10 % w/v forest HD honey significantly enhanced the inhibition of biofilm formation in comparison to dark incubated honey.

Immunization with Pseudomonas aeruginosa vaccines and adjuvant can modulate the type of inflammatory response subsequent to infection

DEFF Research Database (Denmark)

Johansen, H K; Espersen, F; Cryz, S J

1994-01-01

Pseudomonas aeruginosa is the predominant pathogen in patients with cystic fibrosis (CF). To study the possibility of preventing lung inflammation and decreasing the progression of the infection by vaccination, we have developed a rat model of chronic P. aeruginosa lung infection. Rats were......, 2.0 versus 2.1 to 2.8) pathologic abnormalities were less severe in the control rats injected with sterile saline than in the immunized rats and the IFA group. The more severe lung abnormalities observed in immunized rats could be due to the result of immune complex-mediated lung tissue damage...... an acute-type inflammation to a chronic-type inflammation dominated by mononuclear leukocytes and scattered granulomas. Cross-reacting antibodies were induced by the two alginate vaccines, and most immunized animals developed a significant (P

MEDICINAL PLANTS FROM BRAZILIAN CAATINGA: ANTIBIOFILM AND ANTIBACTERIAL ACTIVITIES AGAINST Pseudomonas aeruginosa

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DANIELLE SILVA TRENTIN

2014-01-01

Full Text Available The Caatinga biome covers a vast area in northeastern Brazil and presents a high level of biodiversity. It is known that about 400 plant species are used by semi-arid local communities for medical purposes. Based on ethnopharmacological reports, this study aims to screen 24 species from Caatinga regarding the ability to prevent biofilm formation and to inhibit the growth of Pseudomonas aeruginosa - a major opportunistic human pathogen and an important causative agent of morbidity and mortality. The effects of aqueous extracts, at 0.4 and 4.0 mg mL-1, on biofilm formation and on growth of P. aeruginosa ATCC 27853 were studied using the crystal violet assay and the OD600 absorbance, respectively. The most active extracts were analyzed by thinlayer chromatography and high performance liquid chromatography. Our investigation pointed extracts of four species with potential application for the control of P. aeruginosa: Anadenanthera colubrina (Vell. Brenan, Commiphora leptophloeos (Mart. J.B. Gillett, Myracrodruoun urundeuva Allemão, whose antibiofilm effects (89%, 56% and 79% inhibition of biofilm, respectively were associated with complete inhibition of bacterial growth, and Pityrocarpa moniliformis (Benth. Luckow & R.W. Jobson, which were able avoid 68% of biofilm formation and inhibited 30% bacterial growth. The qualitative phytochemical analyses reveal the complexity of the samples as well as the presence of compounds with high molecular weight.

Decreased outer membrane permeability in imipenem-resistant mutants of Pseudomonas aeruginosa.

OpenAIRE

Trias, J; Dufresne, J; Levesque, R C; Nikaido, H

1989-01-01

The outer membrane of imipenem-resistant mutants of Pseudomonas aeruginosa was shown to have decreased permeability to imipenem but not to cephaloridine. These experiments were performed with intact cells and liposomes containing imipenem-hydrolyzing beta-lactamase derived from Pseudomonas maltophilia, in both cases utilizing an imipenem concentration of 50 microM. In contrast, liposome swelling assays using imipenem at 8 mM detected no significant difference between the imipenem-resistant mu...

The resistome of Pseudomonas aeruginosa in relationship to phenotypic susceptibility.

Science.gov (United States)

Kos, Veronica N; Déraspe, Maxime; McLaughlin, Robert E; Whiteaker, James D; Roy, Paul H; Alm, Richard A; Corbeil, Jacques; Gardner, Humphrey

2015-01-01

Many clinical isolates of Pseudomonas aeruginosa cause infections that are difficult to eradicate due to their resistance to a wide variety of antibiotics. Key genetic determinants of resistance were identified through genome sequences of 390 clinical isolates of P. aeruginosa, obtained from diverse geographic locations collected between 2003 and 2012 and were related to microbiological susceptibility data for meropenem, levofloxacin, and amikacin. β-Lactamases and integron cassette arrangements were enriched in the established multidrug-resistant lineages of sequence types ST111 (predominantly O12) and ST235 (O11). This study demonstrates the utility of next-generation sequencing (NGS) in defining relevant resistance elements and highlights the diversity of resistance determinants within P. aeruginosa. This information is valuable in furthering the design of diagnostics and therapeutics for the treatment of P. aeruginosa infections. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

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

LENUS (Irish Health Repository)

Keating, Deirdre

2013-03-01

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

Multiple roles of biosurfactants in structural biofilm development by Pseudomonas aeruginosa

DEFF Research Database (Denmark)

Pamp, Sünje Johanna; Tolker-Nielsen, Tim

2007-01-01

Recent studies have indicated that biosurfactants produced by Pseudomonas aeruginosa play a role both in maintaining channels between multicellular structures in biofilms and in dispersal of cells from biofilms. Through the use of flow cell technology and enhanced confocal laser scanning microscopy......, we have obtained results which suggest that the biosurfactants produced by P. aeruginosa play additional roles in structural biofilm development. We present genetic evidence that during biofilm development by P. aeruginosa, biosurfactants promote microcolony formation in the initial phase...... and facilitate migration-dependent structural development in the later phase. P. aeruginosa rhl4 mutants, deficient in synthesis of biosurfactants, were not capable of forming microcolonies in the initial phase of biofilm formation. Experiments involving two-color-coded mixed-strain biofilms showed that P...

Variation in hydrogen cyanide production between different strains of Pseudomonas aeruginosa

Czech Academy of Sciences Publication Activity Database

Gilchrist, F. J.; Alcock, A.; Belcher, J.; Brady, M.; Jones, A.; Smith, D.; Španěl, Patrik; Webb, K.; Lenney, W.

2011-01-01

Roč. 38, č. 2 (2011), s. 409-414 ISSN 0903-1936 Institutional research plan: CEZ:AV0Z40400503 Keywords : microbiology * pseudomonas aeruginosa Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.895, year: 2011

Measurement and evaluation of the effects of pH gradients on the antimicrobial and antivirulence activities of chitosan nanoparticles in Pseudomonas aeruginosa

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Fadilah Sfouq Aleanizy

2018-01-01

Full Text Available Objective: The purpose of this study was to study the antimicrobial activity of chitosan nanoparticles (CSNPs on Pseudomonas aeruginosa with special emphasis on their sensitivity to pH and the effect of pH on their activity. Methodology: Antimicrobial activity of CSNPs against Pseudomonas aeruginosa at different pH was tested using broth dilution method. Further assessment of antivirulence activity and sensitization of CSNPs on Pseudomonas aeruginosa were examined. Results: Significant antimicrobial effects of CSNPs against Pseudomonas aeruginosa were detected at slightly acidic pH 5, whereas the activity was abolished at a pH of greater than 7. The antivirulence activity of CSNPs was then investigated and treatment with CSNPs (1000 ppm resulted in a significant reduction or even complete inhibition of pyocyanin production by P. aeruginosa compared with untreated P. aeruginosa indicating the antivirulence activity of CSNPs. CSNPs also sensitized P. aeruginosa to the lytic effects of sodium dodecyl sulfate (SDS; such sensitization was not blocked by washing chitosan-treated cells prior to SDS exposure revealing that CSNPs disturb the outer membrane leading to irreversible sensitivity to detergent even at low concentration (100 ppm. Conclusions: These findings highlight CSNPs as potentially useful as indirect antimicrobial agents for a variety of applications. Keywords: Chitosan nanoparticles, Pseudomonas aeruginosa, pH, Antimicrobial, Virulence

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

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Annie I Chen

2014-10-01

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

Activation of Pseudomonas aeruginosa elastase in Pseudomonas putida by triggering dissociation of the propeptide-enzyme complex

NARCIS (Netherlands)

Braun, P; Bitter, W; Tommassen, J

2000-01-01

The propeptide of Pseudomonas aeruginosa elastase functions both as an intramolecular chaperone required for the folding of the enzyme and as an inhibitor that prevents activity of the enzyme before its secretion into the extracellular medium. Since expression of the lasB gene, which encodes

BOX-PCR is an adequate tool for typing of clinical Pseudomonas aeruginosa isolates

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Katarzyna Rymuza

2012-01-01

Full Text Available In this study, the BOX-PCR fingerprinting technique was evaluated for the discrimination of clinical Pseudomonas aeruginosa isolates. All isolates were typeable and nearly half showed unique banding patterns. According to our results, BOX-PCR fingerprinting is applicable for typing of Pseudomonas aeruginosa isolates and can be considered a useful complementary tool for epidemiological studies of members of this genus. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 4, pp. 734–738

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

DEFF Research Database (Denmark)

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

2012-01-01

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

The effect of in silico targeting Pseudomonas aeruginosa patatin-like protein D, for immunogenic administration.

Science.gov (United States)

Chirani, Alireza Salimi; Majidzadeh, Robabeh; Pouriran, Ramin; Heidary, Mohsen; Nasiri, Mohammad Javad; Gholami, Mehrdad; Goudarzi, Mehdi; Omrani, Vahid Fallah

2018-02-05

The vaccine candidates that have been introduced for immunization against Pseudomonas aeruginosa (P. aeruginosa) strains are quite diverse. In fact, there has been no proper antigen to act as an effective immunogenic substance against this ubiquitous pathogen in the market as yet. The complications caused by this bacterium due to the rapid development of multiple drug resistant strains have led to clinical problems worldwide. P. aeruginosa encodes many specific virulence elements that could be used as appropriate vaccine candidates. Type Vd secretion system, also known as patatin-like protein D, is a novel P. aeruginosa auto-transporter system. It is known that cellular or humoral immune responses could be elevated by chimeric proteins carrying epitopes. It has been recognized that in silico tools are essential for the evaluation of new chimeric antigens. In this study, we have considered the patatin-like protein D (PlpD) molecule from P. aeruginosa and predicted some immunogenic properties of this strong cytotoxic phospholipase A2 with the use of in-depth computational and immunoinformatics assessment methods The novelty of our in silico study is the modeling and assessment of both humoral and cellular immune potential against the PlpD molecule. The molecule was considered by multiple sequence alignment and homology valuation. The extremely conserved regions in the PlpD were predicted. The allergenic and physicochemical property predictions on the PlpD state that the molecule is a non-allergic and stable molecule. High-resolution secondary and tertiary conformations were created. Indeed, the B-cell and T-cell epitope mapping on the chimeric target protein confirmed that the engineered protein contained a tremendous number of both B-cell and T-cell corresponding epitopes. This investigation magnificently attained the chimeric molecule as being a potent lipolytic enzyme composed of numerous B-cell and T-cell restricted epitopes and could induce both humoral and

T helper cell subsets specific for Pseudomonas aeruginosa in healthy individuals and patients with cystic fibrosis.

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Hannah K Bayes

Full Text Available We set out to determine the magnitude of antigen-specific memory T helper cell responses to Pseudomonas aeruginosa in healthy humans and patients with cystic fibrosis.Peripheral blood human memory CD4(+ T cells were co-cultured with dendritic cells that had been infected with different strains of Pseudomonas aeruginosa. The T helper response was determined by measuring proliferation, immunoassay of cytokine output, and immunostaining of intracellular cytokines.Healthy individuals and patients with cystic fibrosis had robust antigen-specific memory CD4(+ T cell responses to Pseudomonas aeruginosa that not only contained a Th1 and Th17 component but also Th22 cells. In contrast to previous descriptions of human Th22 cells, these Pseudomonal-specific Th22 cells lacked the skin homing markers CCR4 or CCR10, although were CCR6(+. Healthy individuals and patients with cystic fibrosis had similar levels of Th22 cells, but the patient group had significantly fewer Th17 cells in peripheral blood.Th22 cells specific to Pseudomonas aeruginosa are induced in both healthy individuals and patients with cystic fibrosis. Along with Th17 cells, they may play an important role in the pulmonary response to this microbe in patients with cystic fibrosis and other conditions.

QUALIDADE BACTERIOLÓGICA DE OVOS CONTAMINADOS COM PSEUDOMONAS AERUGINOSA E ARMAZENADOS EM TEMPERATURA AMBIENTE OU REFRIGERADOS

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Fernanda Rodrigues Mendes

2014-12-01

Full Text Available The aim of this study was to evaluate the effect of sanitization and storage temperature on the quality of commercial eggs inoculated with Pseudomonas aeruginosa. We used 240 large eggs, without cracks, from Dekalb White laying hens at 30 to 40 weeks of age. The experimental design used was two blocks in a 2 x 2 factorial arrange (washed/non-washed and refrigerated/non-refrigerated with twelve replicates. The eggs were contaminated by handling, with 1.5 x 105 colony-forming units (CFU of Pseudomonas aeruginosa and stored at 5 °C and 25 °C for 30 days. Each ten days the eggshell and contents were submitted to bacteriological analyses. Variance analyses were performed and the data were compared by Tukey test. The results showed that Pseudomonas aeruginosa were isolated from the shells and contents of all eggs. Therefore, when the eggs were sanitized and stored at 5 ºC the contamination was less intense. The correlation between the presences of Pseudomonas aeruginosa in the shell and contents was high, when the eggs were not sanitized nor refrigerated. The conclusion of this study was that the egg must be sanitized and refrigerated when the stored for more than 30 days.

Flavonoids Suppress Pseudomonas aeruginosa Virulence through Allosteric Inhibition of Quorum-sensing Receptors*

Science.gov (United States)

Paczkowski, Jon E.; Mukherjee, Sampriti; McCready, Amelia R.; Cong, Jian-Ping; Aquino, Christopher J.; Kim, Hahn; Henke, Brad R.; Smith, Chari D.; Bassler, Bonnie L.

2017-01-01

Quorum sensing is a process of cell-cell communication that bacteria use to regulate collective behaviors. Quorum sensing depends on the production, detection, and group-wide response to extracellular signal molecules called autoinducers. In many bacterial species, quorum sensing controls virulence factor production. Thus, disrupting quorum sensing is considered a promising strategy to combat bacterial pathogenicity. Several members of a family of naturally produced plant metabolites called flavonoids inhibit Pseudomonas aeruginosa biofilm formation by an unknown mechanism. Here, we explore this family of molecules further, and we demonstrate that flavonoids specifically inhibit quorum sensing via antagonism of the autoinducer-binding receptors, LasR and RhlR. Structure-activity relationship analyses demonstrate that the presence of two hydroxyl moieties in the flavone A-ring backbone are essential for potent inhibition of LasR/RhlR. Biochemical analyses reveal that the flavonoids function non-competitively to prevent LasR/RhlR DNA binding. Administration of the flavonoids to P. aeruginosa alters transcription of quorum sensing-controlled target promoters and suppresses virulence factor production, confirming their potential as anti-infectives that do not function by traditional bacteriocidal or bacteriostatic mechanisms. PMID:28119451

Interaction of antibacterial compounds with RND efflux pumps in Pseudomonas aeruginosa

Science.gov (United States)

Dreier, Jürg; Ruggerone, Paolo

2015-01-01

Pseudomonas aeruginosa infections are becoming increasingly difficult to treat due to intrinsic antibiotic resistance and the propensity of this pathogen to accumulate diverse resistance mechanisms. Hyperexpression of efflux pumps of the Resistance-Nodulation-Cell Division (RND)-type multidrug efflux pumps (e.g., MexAB-OprM), chromosomally encoded by mexAB-oprM, mexCD-oprJ, mexEF-oprN, and mexXY (-oprA) is often detected in clinical isolates and contributes to worrying multi-drug resistance phenotypes. Not all antibiotics are affected to the same extent by the aforementioned RND efflux pumps. The impact of efflux on antibiotic activity varies not only between different classes of antibiotics but also between members of the same family of antibiotics. Subtle differences in physicochemical features of compound-pump and compound-solvent interactions largely determine how compounds are affected by efflux activity. The combination of different high-resolution techniques helps to gain insight into the functioning of these molecular machineries. This review discusses substrate recognition patterns based on experimental evidence and computer simulations with a focus on MexB, the pump subunit of the main RND transporter in P. aeruginosa. PMID:26217310

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

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Madison Floyd

2016-11-01

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

Pouring Salt on a Wound: Pseudomonas aeruginosa Virulence Factors Alter Na+ and Cl− Flux in the Lung

Science.gov (United States)

Ballok, Alicia E.

2013-01-01

Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen with multiple niches in the human body, including the lung. P. aeruginosa infections are particularly damaging or fatal for patients with ventilator-associated pneumonia, chronic obstructive pulmonary disease, and cystic fibrosis (CF). To establish an infection, P. aeruginosa relies on a suite of virulence factors, including lipopolysaccharide, phospholipases, exoproteases, phenazines, outer membrane vesicles, type III secreted effectors, flagella, and pili. These factors not only damage the epithelial cell lining but also induce changes in cell physiology and function such as cell shape, membrane permeability, and protein synthesis. While such virulence factors are important in initial infection, many become dysregulated or nonfunctional during the course of chronic infection. Recent work on the virulence factors alkaline protease (AprA) and CF transmembrane conductance regulator inhibitory factor (Cif) show that P. aeruginosa also perturbs epithelial ion transport and osmosis, which may be important for the long-term survival of this microbe in the lung. Here we discuss the literature regarding host physiology-altering virulence factors with a focus on Cif and AprA and their potential roles in chronic infection and immune evasion. PMID:23836869

Induction of beta-lactamase production in Pseudomonas aeruginosa biofilm

DEFF Research Database (Denmark)

Giwercman, B; Jensen, E T; Høiby, N

1991-01-01

Imipenem induced high levels of beta-lactamase production in Pseudomonas aeruginosa biofilms. Piperacillin also induced beta-lactamase production in these biofilms but to a lesser degree. The combination of beta-lactamase production with other protective properties of the biofilm mode of growth c...... could be a major reason for the persistence of this sessile bacterium in chronic infections....

Application of protein typing in molecular epidemiological investigation of nosocomial infection outbreak of aminoglycoside-resistant Pseudomonas aeruginosa.

Science.gov (United States)

Song, Min; Tang, Min; Ding, Yinghuan; Wu, Zecai; Xiang, Chengyu; Yang, Kui; Zhang, Zhang; Li, Baolin; Deng, Zhenghua; Liu, Jinbo

2017-12-16

Pseudomonas aeruginosan has emerged as an important pathogen elated to serious infections and nosocomial outbreaks worldwide. This study was conducted to understand the prevalence of aminoglycoside (AMG)-resistant P. aeruginosa in our hospital and to provide a scientific basis for control measures against nosocomial infections. Eighty-two strains of P. aeruginosa were isolated from clinical departments and divided into AMG-resistant strains and AMG-sensitive strains based on susceptibility test results. AMG-resistant strains were typed by drug resistance gene typing (DRGT) and protein typing. Five kinds of aminoglycoside-modifying enzyme (AME) genes were detected in the AMG-resistant group. AMG-resistant P. aeruginosa strains were classified into three types and six subtypes by DRGT. Four protein peaks, namely, 9900.02, 7600.04, 9101.25 and 10,372.87 Da, were significantly and differentially expressed between the two groups. AMG-resistant P. aeruginosa strains were also categorised into three types and six subtypes at the distance level of 10 by protein typing. AMG-resistant P. aeruginosa was cloned spread in our hospital; the timely implementation of nosocomial infection prevention and control strategies were needed in preventing outbreaks and epidemic of AMG-resistant P. aeruginosa. SELDI-TOF MS technology can be used for bacterial typing, which provides a new method of clinical epidemiological survey and nosocomial infection control.

PSEUDOMONAS AERUGINOSA IN CHRONIC SUPPURATIVE OTITIS MEDIA- A DRUGSENSITIVITY STUDY

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Anoop M

2017-05-01

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

Convergent Metabolic Specialization through Distinct Evolutionary Paths in Pseudomonas aeruginosa

DEFF Research Database (Denmark)

La Rosa, Ruggero; Johansen, Helle Krogh; Molin, Søren

2018-01-01

fibrosis (CF) infection. In this work, we investigated how and through which trajectories evolution of Pseudomonas aeruginosa occurs when migrating from the environment to the airways of CF patients, and specifically, we determined reduction of growth rate and metabolic specialization as signatures...... of adaptive evolution. We show that central metabolic pathways of three distinct Pseudomonas aeruginosa lineages coevolving within the same environment become restructured at the cost of versatility during long-term colonization. Cell physiology changes from naive to adapted phenotypes resulted in (i......) alteration of growth potential that particularly converged to a slow-growth phenotype, (ii) alteration of nutritional requirements due to auxotrophy, (iii) tailored preference for carbon source assimilation from CF sputum, (iv) reduced arginine and pyruvate fermentation processes, and (v) increased oxygen...

Analysis of the antimicrobial activities of a chemokine-derived peptide (CDAP-4) on Pseudomonas aeruginosa

International Nuclear Information System (INIS)

Martinez-Becerra, Francisco; Silva, Daniel-Adriano; Dominguez-Ramirez, Lenin; Mendoza-Hernandez, Guillermo; Lopez-Vidal, Yolanda; Soldevila, Gloria; Garcia-Zepeda, Eduardo A.

2007-01-01

Chemokines are key molecules involved in the control of leukocyte trafficking. Recently, a novel function as antimicrobial proteins has been described. CCL13 is the only member of the MCP chemokine subfamily displaying antimicrobial activity. To determine Key residues involved in its antimicrobial activity, CCL13 derived peptides were synthesized and tested against several bacterial strains, including Pseudomonas aeruginosa. One of these peptides, corresponding to the C-terminal region of CCL13 (CDAP-4) displayed good antimicrobial activity. Electron microscopy studies revealed remarkable morphological changes after CDAP-4 treatment. By computer modeling, CDAP-4 in α helical configuration generated a positive electrostatic potential that extended beyond the surface of the molecule. This feature is similar to other antimicrobial peptides. Altogether, these findings indicate that the antimicrobial activity was displayed by CCL13 resides to some extent at the C-terminal region. Furthermore, CDAP-4 could be considered a good antimicrobial candidate with a potential use against pathogens including P. aeruginosa

Development of a Pseudomonas aeruginosa Agmatine Biosensor

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Adam Gilbertsen

2014-10-01

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

Diversity of Antimicrobial Resistance and Virulence Determinants in Pseudomonas aeruginosa Associated with Fresh Vegetables

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Allydice-Francis, Kashina; Brown, Paul D.

2012-01-01

With the increased focus on healthy eating and consuming raw vegetables, this study assessed the extent of contamination of fresh vegetables by Pseudomonas aeruginosa in Jamaica and examined the antibiotic susceptibility profiles and the presence of various virulence associated determinants of P. aeruginosa. Analyses indicated that vegetables from retail markets and supermarkets were widely contaminated by P. aeruginosa; produce from markets were more frequently contaminated, but the differen...

Community-acquired Pseudomonas aeruginosa-pneumonia in a previously healthy man occupationally exposed to metalworking fluids

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Fernando Peixoto Ferraz de Campos

2014-09-01

Full Text Available Although the Pseudomonas aeruginosa infection is well known and frequently found in hospitals and nursing care facilities, many cases are also reported outside these boundaries. In general, this pathogen infects debilitated patients either by comorbidities or by any form of immunodeficiency. In cases of respiratory infection, tobacco abuse seems to play an important role as a risk factor. In previously healthy patients, community-acquired pneumonia (CAP with P. aeruginosa as the etiological agent is extremely rare, and unlike the cases involving immunocompromised or hospitalized patients, the outcome is severe, and is fatal in up to 61.1% of cases. Aerosolized contaminated water or solutions are closely linked to the development of respiratory tract infection. In this setting, metalworking fluids used in factories may be implicated in CAP involving previously healthy people. The authors report the case of a middle-aged man who worked in a metalworking factory and presented a right upper lobar pneumonia with a rapid fatal outcome. P. aeruginosa was cultured from blood and tracheal aspirates. The autopsy findings confirmed a hemorrhagic necrotizing pneumonia with bacteria-invading vasculitis and thrombosis. A culture of the metalworking fluid of the factory was also positive for P. aeruginosa. The pulsed-field gel electrophoresis showed that both strains (blood culture and metalworking fluid were genetically indistinguishable. The authors highlight the occupational risk for the development of this P. aeruginosa-infection in healthy people.

Comparative evaluation of ciprofloxacin, enoxacin, and ofloxacin in experimental Pseudomonas aeruginosa pneumonia.

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Kemmerich, B; Small, G J; Pennington, J E

1986-01-01

The therapeutic activity of ciprofloxacin, enoxacin, and ofloxacin was evaluated in guinea pigs with acute and chronic experimental Pseudomonas aeruginosa pneumonia. Intratracheal instillations of P. aeruginosa resulted in fatal pneumonia in all untreated animals within 36 h. Among treatment groups (80 mg/kg [body weight] per day), cumulative survival rates were: 47%, ciprofloxacin; 55%, enoxacin; and 42%, ofloxacin. These rates were not significantly different. Intrapulmonary killing of P. a...

Positive signature-tagged mutagenesis in Pseudomonas aeruginosa: tracking patho-adaptive mutations promoting airways chronic infection.

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Irene Bianconi

2011-02-01

Full Text Available The opportunistic pathogen Pseudomonas aeruginosa can establish life-long chronic infections in the airways of cystic fibrosis (CF patients. Persistent lifestyle is established with P. aeruginosa patho-adaptive variants, which are clonal with the initially-acquired strains. Several reports indicated that P. aeruginosa adapts by loss-of-function mutations which enhance fitness in CF airways and sustain its clonal expansion during chronic infection. To validate this model of P. aeruginosa adaptation to CF airways and to identify novel genes involved in this microevolution, we designed a novel approach of positive-selection screening by PCR-based signature-tagged mutagenesis (Pos-STM in a murine model of chronic airways infection. A systematic positive-selection scheme using sequential rounds of in vivo screenings for bacterial maintenance, as opposed to elimination, generated a list of genes whose inactivation increased the colonization and persistence in chronic airways infection. The phenotypes associated to these Pos-STM mutations reflect alterations in diverse aspects of P. aeruginosa biology which include lack of swimming and twitching motility, lack of production of the virulence factors such as pyocyanin, biofilm formation, and metabolic functions. In addition, Pos-STM mutants showed altered invasion and stimulation of immune response when tested in human respiratory epithelial cells, indicating that P. aeruginosa is prone to revise the interaction with its host during persistent lifestyle. Finally, sequence analysis of Pos-STM genes in longitudinally P. aeruginosa isolates from CF patients identified signs of patho-adaptive mutations within the genome. This novel Pos-STM approach identified bacterial functions that can have important clinical implications for the persistent lifestyle and disease progression of the airway chronic infection.

Zingiber officinale: Its antibacterial activity on Pseudomonas aeruginosa and mode of action evaluated by flow cytometry.

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Chakotiya, Ankita Singh; Tanwar, Ankit; Narula, Alka; Sharma, Rakesh Kumar

2017-06-01

Biofilm formation, low membrane permeability and efflux activity developed by Pseudomonas aeruginosa, play an important role in the mechanism of infection and antimicrobial resistance. In the present study we evaluate the antibacterial effect of Zingiber officinale against multi-drug resistant strain of P. aeruginosa. The study explores antibacterial efficacy and time-kill study concomitantly the effect of herbal extract on bacterial cell physiology with the use of flow cytometry and inhibition of biofilm formation. Z. officinale was found to inhibit the growth of P. aeruginosa, significantly. A major decline in the Colony Forming Units was observed with 3 log 10  at 12 h of treatment. Also it is found to affect the membrane integrity of the pathogen, as 70.06 ± 2.009% cells were found to stain with Propidium iodide. In case of efflux activity 86.9 ± 2.08% cells were found in Ethidium bromide positive region. Biofilm formation inhibition ability was found in the range of 68.13 ± 4.11% to 84.86 ± 2.02%. Z.officinale is effective for killing Multi-Drug Resistant P. aeruginosa clinical isolate by affecting the cellular physiology and inhibiting the biofilm formation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Generalized Growth of Estuarine, Household and Clinical Isolates of Pseudomonas aeruginosa.

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Diaz, Kelly E; Remold, Susanna K; Onyiri, Ogochukwu; Bozeman, Maura; Raymond, Peter A; Turner, Paul E

2018-01-01

Pseudomonas aeruginosa is an opportunistic pathogen of particular concern to immune-compromised people, such as cystic fibrosis patients and burn victims. These bacteria grow in built environments including hospitals and households, and in natural environments such as rivers and estuaries. However, there is conflicting evidence whether recent environments like the human lung and open ocean affect P. aeruginosa growth performance in alternate environments. We hypothesized that bacteria recently isolated from dissimilar habitats should grow differently in media containing artificial versus natural resources. To test this idea, we examined growth of P. aeruginosa isolates from three environments (estuary, household, and clinic) in three media types: minimal-glucose lab medium, and media prepared from sugar maple leaves or big bluestem grass. We used automated spectrophotometry to measure high-resolution growth curves for all isolate by media combinations, and studied two fitness parameters: growth rate and maximum population density. Results showed high variability in growth rate among isolates, both overall and in its dependence on assay media, but this variability was not associated with habitat of isolation. In contrast, total growth (change in absorbance over the experiment) differed overall among habitats of isolation, and there were media-specific differences in mean total growth among habitats of isolation, and in among-habitat variability in the media-specific response. This was driven primarily by greater total growth of estuary isolates when compared with those from other habitats of origin, and greater media-specific variability among household isolates than those from other habitats of origin. Taken together, these results suggest that for growth rate P. aeruginosa bacteria appear to be broad generalists without regard to current or recent habitat, whereas for total growth a signature of recent ecological history can be detected.

Generalized Growth of Estuarine, Household and Clinical Isolates of Pseudomonas aeruginosa

Science.gov (United States)

Diaz, Kelly E.; Remold, Susanna K.; Onyiri, Ogochukwu; Bozeman, Maura; Raymond, Peter A.; Turner, Paul E.

2018-01-01

Pseudomonas aeruginosa is an opportunistic pathogen of particular concern to immune-compromised people, such as cystic fibrosis patients and burn victims. These bacteria grow in built environments including hospitals and households, and in natural environments such as rivers and estuaries. However, there is conflicting evidence whether recent environments like the human lung and open ocean affect P. aeruginosa growth performance in alternate environments. We hypothesized that bacteria recently isolated from dissimilar habitats should grow differently in media containing artificial versus natural resources. To test this idea, we examined growth of P. aeruginosa isolates from three environments (estuary, household, and clinic) in three media types: minimal-glucose lab medium, and media prepared from sugar maple leaves or big bluestem grass. We used automated spectrophotometry to measure high-resolution growth curves for all isolate by media combinations, and studied two fitness parameters: growth rate and maximum population density. Results showed high variability in growth rate among isolates, both overall and in its dependence on assay media, but this variability was not associated with habitat of isolation. In contrast, total growth (change in absorbance over the experiment) differed overall among habitats of isolation, and there were media-specific differences in mean total growth among habitats of isolation, and in among-habitat variability in the media-specific response. This was driven primarily by greater total growth of estuary isolates when compared with those from other habitats of origin, and greater media-specific variability among household isolates than those from other habitats of origin. Taken together, these results suggest that for growth rate P. aeruginosa bacteria appear to be broad generalists without regard to current or recent habitat, whereas for total growth a signature of recent ecological history can be detected. PMID:29599754

Generalized Growth of Estuarine, Household and Clinical Isolates of Pseudomonas aeruginosa

Directory of Open Access Journals (Sweden)

Kelly E. Diaz

2018-02-01

Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen of particular concern to immune-compromised people, such as cystic fibrosis patients and burn victims. These bacteria grow in built environments including hospitals and households, and in natural environments such as rivers and estuaries. However, there is conflicting evidence whether recent environments like the human lung and open ocean affect P. aeruginosa growth performance in alternate environments. We hypothesized that bacteria recently isolated from dissimilar habitats should grow differently in media containing artificial versus natural resources. To test this idea, we examined growth of P. aeruginosa isolates from three environments (estuary, household, and clinic in three media types: minimal-glucose lab medium, and media prepared from sugar maple leaves or big bluestem grass. We used automated spectrophotometry to measure high-resolution growth curves for all isolate by media combinations, and studied two fitness parameters: growth rate and maximum population density. Results showed high variability in growth rate among isolates, both overall and in its dependence on assay media, but this variability was not associated with habitat of isolation. In contrast, total growth (change in absorbance over the experiment differed overall among habitats of isolation, and there were media-specific differences in mean total growth among habitats of isolation, and in among-habitat variability in the media-specific response. This was driven primarily by greater total growth of estuary isolates when compared with those from other habitats of origin, and greater media-specific variability among household isolates than those from other habitats of origin. Taken together, these results suggest that for growth rate P. aeruginosa bacteria appear to be broad generalists without regard to current or recent habitat, whereas for total growth a signature of recent ecological history can be detected.

Comparison of Pseudomonas aeruginosa isolates from mink by serotyping and pulsed-field gel electrophoresis

DEFF Research Database (Denmark)

Hammer, Anne Sofie; Pedersen, Karl; Andersen, Thomas Holmen

2003-01-01

Isolates of Pseudomonas aeruginosa from clinical infections in mink were subjected to serotyping and pulsed-field gel electrophoresis (PFGE) using SpeI. A total of 212 isolates of P aeruginosa from the year 1998 to 2001 were included in this study: 168 isolates from mink obtained from 74 farm out...

Multiple roles of Pseudomonas aeruginosa TBCF10839 PilY1 in motility, transport and infection

DEFF Research Database (Denmark)

Bohn, Yu-Sing Tammy; Brandes, Gudrun; Rakhimova, Elza

2009-01-01

Polymorphonuclear neutrophils are the most important mammalian host defence cells against infections with Pseudomonas aeruginosa. Screening of a signature tagged mutagenesis library of the non-piliated P. aeruginosa strain TBCF10839 uncovered that transposon inactivation of its pilY1 gene rendere...

Pseudomonas aeruginosa adaptation to lungs of cystic fibrosis patients leads to lowered resistance to phage and protist enemies.

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Ville-Petri Friman

Full Text Available Pathogenic life styles can lead to highly specialized interactions with host species, potentially resulting in fitness trade-offs in other ecological contexts. Here we studied how adaptation of the environmentally transmitted bacterial pathogen, Pseudomonas aeruginosa, to cystic fibrosis (CF patients affects its survival in the presence of natural phage (14/1, ΦKZ, PNM and PT7 and protist (Tetrahymena thermophila and Acanthamoebae polyphaga enemies. We found that most of the bacteria isolated from relatively recently intermittently colonised patients (1-25 months, were innately phage-resistant and highly toxic for protists. In contrast, bacteria isolated from long time chronically infected patients (2-23 years, were less efficient in both resisting phages and killing protists. Moreover, chronic isolates showed reduced killing of wax moth larvae (Galleria mellonella probably due to weaker in vitro growth and protease expression. These results suggest that P. aeruginosa long-term adaptation to CF-lungs could trade off with its survival in aquatic environmental reservoirs in the presence of microbial enemies, while lowered virulence could reduce pathogen opportunities to infect insect vectors; factors that are both likely to result in poorer environmental transmission. From an applied perspective, phage therapy could be useful against chronic P. aeruginosa lung infections that are often characterized by multidrug resistance: chronic isolates were least resistant to phages and their poor growth will likely slow down the emergence of beneficial resistance mutations.

Risk factors for colonization and infection by Pseudomonas aeruginosa in patients hospitalized in intensive care units in France

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Hoang, S.; Georget, A.; Asselineau, J.; Venier, A-G.; Leroyer, C.; Rogues, A. M.; Thiébaut, R.

2018-01-01

Pseudomonas aeruginosa (P.aeruginosa) remains a prominent nosocomial pathogen responsible for high morbi-mortality in intensive care units (ICUs). P.aeruginosa transmission is known to be partly endogenous and exogenous. Main factors have been highlighted but the precise role of environment in regard to antibiotics use remained unclear. Objective To assess the role of environment, medical care and individual risks factors for P. aeruginosa colonization and infection. Study design and setting A French multicentric prospective study involved ten ICUs for a five months period. Every adult patient newly hospitalized in ICUs with no P. aeruginosa carriage up to 48 hours after admission was included and weekly screened before discharge or death. Screening swabs were either rectal, sputum or oropharyngeal samples. Hydric environment was also sampled each week. Data on patient clinical features, environmental and device exposures, and antibiotics supports were regularly collected. Multivariate analysis was performed with a multistate model. Results The overall prevalence of P. aeruginosa carriage was 15.3% (201/1314). Risk factors associated with patient colonization were: use of inactive antibiotics against P. aeruginosa (HR = 1.60 [1.15–2.21] pinfection (HR = 0.64 [0.41–1.01] p = 0.05). Interaction between hydric environment antibiotics support was not statistically associated with patient colonization. Conclusion Hydric contamination and antibiotics pressure seem to remain key independent risk factors in P. aeruginosa colonization. These results advocate the need to carry on preventive and targeted interventions toward healthcare associated infections. PMID:29522559

Purification, crystallization and preliminary X-ray diffraction analysis of the C-terminal fragment of the MvfR protein from Pseudomonas aeruginosa

International Nuclear Information System (INIS)

Kefala, Katerina; Kotsifaki, Dina; Providaki, Mary; Kapetaniou, Evangelia G.; Rahme, Lawrence; Kokkinidis, Michael

2012-01-01

MvfRC87, a 242-residue C-terminal segment of the LysR-type transcriptional regulator MvfR, was produced in Escherichia coli, purified and crystallized. The LysR-type transcriptional regulator MvfR plays a critical role in Pseudomonas aeruginosa pathogenicity via the transcriptional regulation of multiple quorum-sensing-regulated virulence factors. The protein also controls pathogenic type VI secretion loci. MvfRC87, a 242-residue C-terminal segment of MvfR, was produced in Escherichia coli, purified and crystallized. X-ray diffraction data were collected using synchrotron radiation and crystallographic parameters were determined

The global regulator Crc plays a multifaceted role in modulation of type III secretion system in Pseudomonas aeruginosa.

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Dong, Yi-Hu; Zhang, Xi-Fen; Zhang, Lian-Hui

2013-02-01

The opportunistic pathogen Pseudomonas aeruginosa utilizes type III secretion system (T3SS) to translocate effector proteins into eukaryotic host cells that subvert normal host cell functions to the benefit of the pathogen, and results in serious infections. T3SS in P. aeruginosa is controlled by a complex system of regulatory mechanisms and signaling pathways. In this study, we described that Crc, an RNA-binding protein, exerts a positive impact on T3SS in P. aeruginosa, as evidenced by promoter activity assays of several key T3SS genes, transcriptomics, RT-PCR, and immunoblotting in crc mutant. We further demonstrated that the regulatory function of Crc on the T3SS was mediated through the T3SS master regulator ExsA and linked to the Cbr/Crc signaling system. Expression profiling of the crc mutant revealed a downregulation of flagship T3SS genes as well as 16 other genes known to regulate T3SS gene expression in P. aeruginosa. On the basis of these data, we proposed that Crc may exert multifaceted control on the T3SS through various pathways, which may serve to fine-tune this virulence mechanism in response to environmental changes and nutrient sources. © 2012 The Authors. Published by Blackwell Publishing Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Pseudomonas aeruginosa Biofilm, a Programmed Bacterial Life for Fitness.

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Lee, Keehoon; Yoon, Sang Sun

2017-06-28

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

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

OpenAIRE

Guida, Marco; Di Onofrio, Valeria; Gall?, Francesca; Gesuele, Renato; Valeriani, Federica; Liguori, Renato; Romano Spica, Vincenzo; Liguori, Giorgio

2016-01-01

Pseudomonas aeruginosa is frequently isolated in swimming pool settings. Nine recreational and rehabilitative swimming pools were monitored according to the local legislation. The presence of P. aeruginosa was correlated to chlorine concentration. The ability of the isolates to form a biofilm on plastic materials was also investigated. In 59.5% of the samples, microbial contamination exceeded the threshold values. P. aeruginosa was isolated in 50.8% of these samples. The presence of P. aerugi...

The LasB Elastase of Pseudomonas aeruginosa Acts in Concert with Alkaline Protease AprA To Prevent Flagellin-Mediated Immune Recognition.

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Casilag, Fiordiligie; Lorenz, Anne; Krueger, Jonas; Klawonn, Frank; Weiss, Siegfried; Häussler, Susanne

2016-01-01

The opportunistic pathogen Pseudomonas aeruginosa is capable of establishing severe and persistent infections in various eukaryotic hosts. It encodes a wide array of virulence factors and employs several strategies to evade immune detection. In the present study, we screened the Harvard Medical School transposon mutant library of P. aeruginosa PA14 for bacterial factors that modulate interleukin-8 responses in A549 human airway epithelial cells. We found that in addition to the previously identified alkaline protease AprA, the elastase LasB is capable of degrading exogenous flagellin under calcium-replete conditions and prevents flagellin-mediated immune recognition. Our results indicate that the production of two proteases with anti-flagellin activity provides a failsafe mechanism for P. aeruginosa to ensure the maintenance of protease-dependent immune-modulating functions. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Investigating the link between imipenem resistance and biofilm formation by Pseudomonas aeruginosa.

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Musafer, Hadeel K; Kuchma, Sherry L; Naimie, Amanda A; Schwartzman, Joseph D; Al-Mathkhury, Harith J Fahad; O'Toole, George A

2014-07-01

Pseudomonas aeruginosa, a ubiquitous environmental organism, is a difficult-to-treat opportunistic pathogen due to its broad-spectrum antibiotic resistance and its ability to form biofilms. In this study, we investigate the link between resistance to a clinically important antibiotic, imipenem, and biofilm formation. First, we observed that the laboratory strain P. aeruginosa PAO1 carrying a mutation in the oprD gene, which confers resistance to imipenem, showed a modest reduction in biofilm formation. We also observed an inverse relationship between imipenem resistance and biofilm formation for imipenem-resistant strains selected in vitro, as well as for clinical isolates. We identified two clinical isolates of P. aeruginosa from the sputum of cystic fibrosis patients that formed robust biofilms, but were sensitive to imipenem (MIC ≤ 2 μg/ml). To test the hypothesis that there is a general link between imipenem resistance and biofilm formation, we performed transposon mutagenesis of these two clinical strains to identify mutants defective in biofilm formation, and then tested these mutants for imipenem resistance. Analysis of the transposon mutants revealed a role for previously described biofilm factors in these clinical isolates of P. aeruginosa, including mutations in the pilY1, pilX, pilW, algC, and pslI genes, but none of the biofilm-deficient mutants became imipenem resistant (MIC ≥ 8 μg/ml), arguing against a general link between biofilm formation and resistance to imipenem. Thus, assessing biofilm formation capabilities of environmental isolates is unlikely to serve as a good predictor of imipenem resistance. We also discuss our findings in light of the limited literature addressing planktonic antibiotic resistance factors that impact biofilm formation.

Effects of PslG on the surface movement of Pseudomonas aeruginosa.

Science.gov (United States)

Zhang, Jingchao; He, Jing; Zhai, Chunhui; Ma, Luyan Z; Gu, Lichuan; Zhao, Kun

2018-05-04

PslG attracted a lot of attention recently due to its great potential abilities in inhibiting biofilms of Pseudomonas aeruginosa However, how PslG affects biofilm development still remains largely unexplored. Here, we focused on the surface motility of bacterial cells, which is critical for biofilm development. We studied the effect of PslG on bacterial surface movement in early biofilm development at a single-cell resolution by using a high-throughput bacterial tracking technique. The results showed that compared with no exogenous PslG addition, when PslG was added to the medium, bacterial surface movement was significantly faster by 4 ∼ 5 times, and was in a more random way with no clear preferred direction. A further study revealed that the fraction of walking mode increased when PslG was added, which then resulted in an elevated average speed. The differences of motility due to PslG addition led to a clear distinction in patterns of bacterial surface movement, and retarded microcolony formation greatly. Our results provide insight into developing new PslG-based biofilm-control techniques. IMPORTANCE Biofilms of Pseudomonas aeruginosa are a major cause for hospital-acquired infections. They are notoriously difficult to eradicate and pose serious health hazard to our human society. So finding new ways to control biofilms are urgently needed. Recent work on PslG showed that PslG might be a good candidate for inhibiting/disassembling biofilms of Pseudomonas aeruginosa through Psl-based regulation. However, to fully explore PslG functions in biofilm-control, a better understanding of PslG-Psl interactions is needed. Toward this end, we examined the effect of PslG on the surface movement of Pseudomonas aeruginosa in this work. The significance of our work is in greatly enhancing our understanding of the inhibiting mechanism of PslG on biofilms by providing a detailed picture of bacterial surface movement at a single-cell level, which will allow a full understanding

High level of resistance to aztreonam and ticarcillin in Pseudomonas aeruginosa isolated from soil of different crops in Brazil.

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Pitondo-Silva, André; Martins, Vinicius Vicente; Fernandes, Ana Flavia Tonelli; Stehling, Eliana Guedes

2014-03-01

Pseudomonas aeruginosa can be found in water, soil, plants and, human and animal fecal samples. It is an important nosocomial pathogenic agent characterized by an intrinsic resistance to multiple antimicrobial agents and the ability to develop high-level (acquired) multidrug resistance through some mechanisms, among them, by the acquisition of plasmids and integrons, which are mobile genetic elements. In this study, 40 isolates from Brazilian soil were analyzed for antibiotic resistance, presence of integrons and plasmidial profile. The results demonstrated that the vast majority of the isolates have shown resistance for aztreonam (92.5%, n=37) and ticarcillin (85%, n=34), four isolates presented plasmids and eight isolates possess the class 1 integron. These results demonstrated that environmental isolates of P. aeruginosa possess surprising antibiotic resistance profile to aztreonam and ticarcillin, two antimicrobial agents for clinical treatment of cystic fibrosis patients and other infections occurred by P. aeruginosa. Copyright © 2014 Elsevier B.V. All rights reserved.

Pseudomonas aeruginosa with lasI quorum-sensing deficiency during corneal infection

DEFF Research Database (Denmark)

Zhu, H.; Bandara, R.; Conibear, T.C.

2004-01-01

To understand the importance of Pseudomonas aeruginosa quorum-sensing systems in the development of corneal infection, the genotypic characteristics and pathogenesis of seven ocular isolates with low-protease and acyl homoserine lactone (AHL) activity and quorum-sensing mutants of PAO1 deficient...

Flagellation of Pseudomonas aeruginosa in newly divided cells

Science.gov (United States)

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

2015-03-01

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

Glycine metabolism by Pseudomonas aeruginosa: hydrogen cyanide biosynthesis

International Nuclear Information System (INIS)

Castric, P.A.

1977-01-01

Hydrogen cyanide (HCN) production by Pseudomonas aeruginosa in a synthetic medium is stimulated by the presence of glycine. Methionine enhances this stimulation but will not substitute for glycine as a stimulator of cyanogenesis. Threonine and phenylalanine are effective substitutes for glycine in the stimulation of HCN production. Glycine, threonine, and serine are good radioisotope precursors of HCN, but methionine and phenylalanine are not. Cell extracts of P. aeruginosa convert [ 14 C]threonine to [ 14 C]glycine. H14CN is produced with low dilution of label from either [1- 14 C]glycine or [2- 14 C]glycine, indicating a randomization of label either in the primary or secondary metabolism of glycine. When whole cells were fed [1,2- 14 C]glycine, cyanide and bicarbonate were the only radioactive extracellular products observed

Electrochemical reduction of oxygen catalyzed by Pseudomonas aeruginosa

Energy Technology Data Exchange (ETDEWEB)

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

2010-07-01

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

Two cases of Pseudomonas aeruginosa epidural abscesses and cervical osteomyelitis after dental extractions.

Science.gov (United States)

Walters, Heather L; Measley, Robert

2008-04-20

Case report. To report 2 unusual cases of Pseudomonas aeruginosa epidural abscesses and cervical osteomyelitis after routine dental extractions and to review relevant literature. Pseudomonas aeruginosa is a rare cause of cervical osteomyelitis in patients after dental extractions. Only 1 prior case could be found in the literature. The cases of an 18-year-old male and a 23-year-old female are presented. PubMed was used to search for relevant literature. Our 2 patients presented with excruciating neck pain within 24 hours of routine dental extractions and, by imaging were found to have cervical epidural abscesses and osteomyelitis. Both patients were taken to the operating room for drainage and corpectomy and treated with prolonged courses of intravenous antibiotics. When seen in follow up 3 months later, neither patient demonstrated any neurologic sequelae. Pseudomonas aeruginosa epidural abscesses and osteomyelitis of the cervical spine have only rarely been reported in healthy patients after dental extractions. To our knowledge, the 2 patients reported here are only the second 2 such cases reported in the literature. Unfortunately, as in prior cases, these 2 patients had a significant delay in diagnosis. Therefore, a strong suspicion must be maintained for all patients presenting with neck pain after a recent dental extraction and appropriate imaging must be obtained urgently.

Pseudomonas aeruginosa septic shock associated with ecthyma gangrenosum in an infant with agammaglobulinemia Choque séptico por Pseudomonas aeruginosa associado a éctima gangrenosa em criança com agamaglobulinemia

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João Fernando Lourenço de ALMEIDA

2002-01-01

Full Text Available Ecthyma gangrenosum (EG due to Pseudomonas aeruginosa is a rare and invasive infection that can be associated with agammaglobulinemia. The cornerstone of the treatment is based on prompt recognition with appropriate antibiotic coverage and intravenous immunoglobulin. The authors report a case of EG emphasizing the clinical and therapeutic aspects of this condition.Éctima Gangrenosa (EG por Pseudomonas aeruginosa é uma infecção rara e invasiva que pode ser associada com agamaglobulinemia. O tratamento fundamental é baseado no pronto reconhecimento com cobertura de antibiótico apropriada e imunoglobulina intravenosa. Os autores relatam caso de EG dando ênfase aos aspectos clínicos e terapêuticos desta condição.

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

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

2016-01-01

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes chronic lung infection in patients with cystic fibrosis (CF) and acute systemic infections in severely burned patients and immunocompromised patients including cancer patients undergoing chemotherapy and HIV infected individuals. In response to the environmental conditions at specific infection sites, P. aeruginosa expresses certain sets of cell-associated and extracellular virulence factors that produce tissue damage. Analyzing the mechanisms that govern the production of these virulence factors in vitro requires media that closely mimic the environmental conditions within the infection sites. In this chapter, we review studies based on media that closely resemble three in vivo conditions, the thick mucus accumulated within the lung alveoli of CF patients, the serum-rich wound bed and the bloodstream. Media resembling the CF alveolar mucus include standard laboratory media supplemented with sputum obtained from CF patients as well as prepared synthetic mucus media formulated to contain the individual components of CF sputum. Media supplemented with serum or individual serum components have served as surrogates for the soluble host components of wound infections, while whole blood has been used to investigate the adaptation of pathogens to the bloodstream. Studies using these media have provided valuable information regarding P. aeruginosa gene expression in different host environments as varying sets of genes were differentially regulated during growth in each medium. The unique effects observed indicate the essential role of these in vitro media that closely mimic the in vivo conditions in providing accurate information regarding the pathogenesis of P. aeruginosa infections. Copyright © 2016 Elsevier Inc. All rights reserved.

A comparative study of coastal and clinical isolates of Pseudomonas aeruginosa

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Anusree V. Nair

2015-09-01

Full Text Available Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium having a versatile metabolic potential and great ecological and clinical significance. The geographical distribution of P. aeruginosahas revealed the existence of an unbiased genetic arrangement in terrestrial isolates. In contrast, there are very few reports about P. aeruginosa strains from marine environments. The present work was aimed at studying the distribution of P. aeruginosa in coastal waters along the Indian Peninsula and understanding the environmental influence on genotypic, metabolic and phenotypic characteristics by comparing marine and clinical isolates. Of the 785 marine isolates obtained on selective media, only 32 (~4.1% were identified as P. aeruginosa, based on their fatty acid methyl ester profiles. A low Euclidian distance value (P. aeruginosa. While biogeographical separation was not evident based solely on phenotypic and metabolic typing, genomic and metatranscriptomic studies are more likely to show differences between these isolates. Thus, newer and more insightful methods are required to understand the ecological distribution of this complex group of bacteria.

Pseudomonas aeruginosa: disseminação de resistência antimicrobiana em efluente hospitalar e água superficial Pseudomonas aeruginosa: spread of antimicrobial resistance in hospital effluent and surface water

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Daiane Bopp Fuentefria

2008-10-01

Full Text Available O objetivo deste estudo foi comparar amostras de efluente do Hospital São Vicente de Paulo com amostras de água do Rio Passo Fundo, quanto ao perfil de susceptibilidade de isolados de Pseudomonas aeruginosa, para inferir sobre a presença de isolados de origem hospitalar em amostras de água superficial. A significância estatística entre os perfis de susceptibilidade das amostras foi testada por análise de variância e a comparação das amostras foi feita por contrastes de interesse. Foram identificados 198 isolados de Pseudomonas aeruginosa a partir das amostras analisadas. O fenótipo de multirresistência não foi observado nas amostras do Rio Passo Fundo, embora alguns isolados resistentes a carbapenêmicos tenham sido identificados, indicando a presença de contaminação com bactérias provenientes de um ambiente sob forte pressão seletiva. Diferenças significativas entre as amostras de água e efluente hospitalar foram observadas a partir da análise de variância por contrastes de interesse.The aim of this study was to compare sewage samples from Hospital São Vicente de Paulo with water samples from the Passo Fundo river, with regard to the susceptibility profile of Pseudomonas aeruginosa isolates, in order to make inferences about the presence of strains of hospital origin in surface water samples. The statistical significance between the susceptibility profiles of the samples was tested using analysis of variance, and the samples were compared by means of contrasts of interest. One hundred and ninety-eight isolates of Pseudomonas aeruginosa were recovered from the samples analyzed. No phenotype for multiresistance was found in the samples from the Passo Fundo river, although some carbapenem-resistant isolates were identified, thereby indicating the presence of contamination with bacteria derived from an environment under strong selection pressure. Significant differences between the water and hospital effluent samples were

Modification the ELISA Kit for diagnosis of “Pseudomonas aeruginosa and comparing it with ordinary ELISA kit”

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Taghreed A. Mohammad

2017-07-01

Full Text Available The first aim of the present study was to diagnosis Pseudomonas  aeruginosa by many tests. This study consisted "200 patients " who suffered from burn wound and compare with 100 health individuals (male and female as a control group, Vitek test was used to diagnose  118 (87 "local isolate  ATCC 15692" with 31 other isolate of Pseudomonas  aeruginosa  ((ATCC 15690, ATCC 15688  from 200 samples which were taken from burn patients. This result was similar to Analytical profile index ( API   test (118 isolates of  P. aeruginosa with 82 isolations of  other bacteria. Then the detection P. aeruginosa isolate  ATCC 15692 by new ELISA Technique and comparing its with modify the ordinary ELISA kit.

Ciprofloxacin interactions with imipenem and amikacin against multiresistant Pseudomonas aeruginosa.

OpenAIRE

Giamarellou, H; Petrikkos, G

1987-01-01

In vitro interactions of ciprofloxacin with imipenem and amikacin were evaluated by the killing-curve technique against 26 Pseudomonas aeruginosa strains resistant to amikacin and resistant or moderately susceptible to ciprofloxacin and imipenem. Imipenem enhanced killing by ciprofloxacin in tests with 11 strains, whereas amikacin enhanced killing in tests with only 4 strains.

Genome-Wide Survey of Pseudomonas aeruginosa PA14 Reveals a Role for the Glyoxylate Pathway and Extracellular Proteases in the Utilization of Mucin

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Flynn, Jeffrey M.; Phan, Chi

2017-01-01

ABSTRACT Chronic airway infections by the opportunistic pathogen Pseudomonas aeruginosa are a major cause of mortality in cystic fibrosis (CF) patients. Although this bacterium has been extensively studied for its virulence determinants, biofilm growth, and immune evasion mechanisms, comparatively little is known about the nutrient sources that sustain its growth in vivo. Respiratory mucins represent a potentially abundant bioavailable nutrient source, although we have recently shown that canonical pathogens inefficiently use these host glycoproteins as a growth substrate. However, given that P. aeruginosa, particularly in its biofilm mode of growth, is thought to grow slowly in vivo, the inefficient use of mucin glycoproteins may be relevant to its persistence within the CF airways. To this end, we used whole-genome fitness analysis, combining transposon mutagenesis with high-throughput sequencing, to identify genetic determinants required for P. aeruginosa growth using intact purified mucins as a sole carbon source. Our analysis reveals a biphasic growth phenotype, during which the glyoxylate pathway and amino acid biosynthetic machinery are required for mucin utilization. Secondary analyses confirmed the simultaneous liberation and consumption of acetate during mucin degradation and revealed a central role for the extracellular proteases LasB and AprA. Together, these studies describe a molecular basis for mucin-based nutrient acquisition by P. aeruginosa and reveal a host-pathogen dynamic that may contribute to its persistence within the CF airways. PMID:28507068

Effects of hyperbaric oxygen on Pseudomonas aeruginosa susceptibility to imipenem and macrophages.

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Lima, Flavia Luna; Joazeiro, Paulo Pinto; Lancellotti, Marcelo; de Hollanda, Luciana Maria; de Araújo Lima, Bruna; Linares, Edlaine; Augusto, Ohara; Brocchi, Marcelo; Giorgio, Selma

2015-01-01

The seriousness to treat burn wounds infected with Pseudomonas aeruginosa led us to examine whether the effect of the carbapenem antibiotic imipenem is enhanced by hyperbaric oxygen (HBO). The effects of HBO (100% O2, 3 ATA, 5 h) in combination with imipenen on bacterial counts of six isolates of P. aeruginosa and bacterial ultrastructure were investigated. Infected macrophages were exposed to HBO (100% O2, 3 ATA, 90 min) and the production of reactive oxygen species monitored. HBO enhanced the effects of imipenen. HBO increased superoxide anion production by macrophages and likely kills bacteria by oxidative mechanisms. HBO in combination with imipenem can be used to kill P. aeruginosa in vitro and such treatment may be beneficial for the patients with injuries containing the P. aeruginosa.

Antibiotic resistance pattern and prevalence of qacEΔ1 and sul1 genes in Pseudomonas aeruginosa from hospital wastewater

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Rosa Maria Pinto Novaes

2018-05-01

Full Text Available Introduction: Hospital effluents may pose great environmental risk due to the presence of pathogenic microorganisms, drugs and chemical components. Pseudomonas aeruginosa is an opportunistic pathogen frequently found in hospital environment. Objective: To evaluate the resistome of P. aeruginosa from the hospital wastewater treatment plant (HWTP in a hospital complex of Rio de Janeiro city. Method: Twenty isolates from the five stages of the HWTP were identified as P. aeruginosa by 16S rRNA gene sequencing analysis. Susceptibility to antibiotics was determined according to CLSI and qacEΔ1 and sul1 genes were detected by PCR. Sulphonamide residues were investigated by high performance liquid chromatography coupled to sequential mass spectrometry. Results: The sulfamethoxazole has been demonstrated at a level below 50 ng L-1. Sulfonamide resistance (80% has been demonstrated followed by quinolone class (50% and 13 susceptibility patterns to antimicrobials. The qacEΔ1-sul1 genes were detected in 100% of isolates suggesting the presence of class 1 integrons in the whole HWTP. Conclusions: The results signalized limitations of HWTP and propagation of resistance genes in all stages of the HWTP. These data also contribute to the environmental sanitary surveillance in the design of prevention actions against negative impact on the public health.

Pesquisa de Acinetobacter sp e Pseudomonas aeruginosa produtores de metalo-β-lactamase em hospital de emergência de Porto Alegre, Estado do Rio Grande do Sul, Brasil Investigation of metallo-β-lactamase-producing Acinetobacter sp and Pseudomonas aeruginosa at an emergency hospital in Porto Alegre, State of Rio Grande do Sul, Brazil

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Vani Dos Santos Laranjeira

2010-08-01

Full Text Available INTRODUÇÃO: O aparecimento de Pseudomonas aeruginosa e Acinetobacter sp produtores de metalo-β-lactamases (MBLs é um desafio para os hospitais. MÉTODOS: Verificou-se a produção de MBL em cepas clínicas de Pseudomonas aeruginosa e Acinetobacter sp de um hospital de emergência de Porto Alegre pelo método de aproximação de disco e E-test MBL. Os genes bla foram pesquisados pela PCR. RESULTADOS: Duas cepas de Pseudomonas aeruginosa e oito Acinetobacter sp demonstraram fenótipo de MBLs. A amplificação do gene blaSPM-1 confirmou a enzima em P. aeruginosa.. CONCLUSÕES: Deve-se ter cautela ao avaliar testes fenotípicos utilizados na detecção rotineira de metalo-enzima.INTRODUCTION: The appearance of metallo-β-lactamase (MBL-producing Pseudomonas aeruginosa and Acinetobacter sp. is a challenge for hospitals. METHODS: The production of MBL in clinical isolates of Pseudomonas aeruginosa and Acinetobacter sp. From an emergency hospital in Porto Alegre was investigated using the disk approximation test and MBL E-test. The bla genes were determined using PCR. RESULTS: Two strains of Pseudomonas aeruginosa and eight of Acinetobacter sp were shown to be MBL phenotypes. Amplification of the blaSPM-1 gene confirmed the presence of the enzyme in P. aeruginosa. CONCLUSIONS: Caution is needed in evaluating phenotype tests used for routine detection of metallo-β-lactamases.

Pseudomonas aeruginosa alginate is refractory to Th1 immune response and impedes host immune clearance in a mouse model of acute lung infection

DEFF Research Database (Denmark)

Song, Zhijun; Wu, Hong; Ciofu, Oana

2003-01-01

. The effect of alginate production on pathogenicity was investigated by using an acute lung infection mouse model that compared a non-mucoid P. aeruginosa strain, PAO1, to its constitutive alginate-overproducing derivative, Alg(+) PAOmucA22, and an alginate-defective strain, Alg(-) PAOalgD. Bacterial......Pseudomonas aeruginosa is an opportunistic respiratory pathogen that accounts for most of the morbidity and mortality in cystic fibrosis (CF) patients. In CF-affected lungs, the bacteria undergo conversion from a non-mucoid to a non-tractable mucoid phenotype, due to overproduction of alginate...... suspensions were instilled into the left bronchus and examined 24 and 48 h post-infection. The highest bacterial loads and the most severe lung pathology were observed with strain Alg(-) PAOalgD at 24 h post-infection, which may have been due to an increase in expression of bacterial elastase by the mutant...

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

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Jing Shao

2012-09-01

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

Pel is a cationic exopolysaccharide that cross-links extracellular DNA in the Pseudomonas aeruginosa biofilm matrix.

Science.gov (United States)

Jennings, Laura K; Storek, Kelly M; Ledvina, Hannah E; Coulon, Charlène; Marmont, Lindsey S; Sadovskaya, Irina; Secor, Patrick R; Tseng, Boo Shan; Scian, Michele; Filloux, Alain; Wozniak, Daniel J; Howell, P Lynne; Parsek, Matthew R

2015-09-08

Biofilm formation is a complex, ordered process. In the opportunistic pathogen Pseudomonas aeruginosa, Psl and Pel exopolysaccharides and extracellular DNA (eDNA) serve as structural components of the biofilm matrix. Despite intensive study, Pel's chemical structure and spatial localization within mature biofilms remain unknown. Using specialized carbohydrate chemical analyses, we unexpectedly found that Pel is a positively charged exopolysaccharide composed of partially acetylated 1→4 glycosidic linkages of N-acetylgalactosamine and N-acetylglucosamine. Guided by the knowledge of Pel's sugar composition, we developed a tool for the direct visualization of Pel in biofilms by combining Pel-specific Wisteria floribunda lectin staining with confocal microscopy. The results indicate that Pel cross-links eDNA in the biofilm stalk via ionic interactions. Our data demonstrate that the cationic charge of Pel is distinct from that of other known P. aeruginosa exopolysaccharides and is instrumental in its ability to interact with other key biofilm matrix components.

Mass Spectrometric Characterization of Oligomers in Pseudomonas aeruginosa Azurin Solutions

Czech Academy of Sciences Publication Activity Database

Sokolová, L.; Williamson, H.; Sýkora, Jan; Hof, Martin; Gray, H. B.; Brutschy, B.; Vlček, Antonín

2011-01-01

Roč. 115, č. 16 (2011), s. 4790-4800 ISSN 1520-6106 R&D Projects: GA MŠk(CZ) ME10124; GA MŠk(CZ) LC06063 Institutional research plan: CEZ:AV0Z40400503 Keywords : mass spectrometry * oligomers * pseudomonas aeruginosa azurin solutions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.696, year: 2011

Multiple antibiotic susceptibility of polyphosphate kinase mutants (ppk1 and ppk2 from Pseudomonas aeruginosa PAO1 as revealed by global phenotypic analysis

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Javiera Ortiz-Severín

2015-01-01

Full Text Available BACKGROUND: Pseudomonas aeruginosa is known to be a multidrug resistant opportunistic pathogen. Particularly, P. aeruginosa PAO1 polyphosphate kinase mutant (ppk1 is deficient in motility, quorum sensing, biofilm formation and virulence FINDINGS: By using Phenotypic Microarrays (PM we analyzed near 2000 phenotypes of P. aeruginosa PAO1 polyP kinase mutants (ppk1 and ppk2. We found that both ppk mutants shared most of the phenotypic changes and interestingly many of them related to susceptibility toward numerous and different type of antibiotics such as Ciprofloxacin, Chloramphenicol and Rifampicin CONCLUSIONS: Combining the fact that ppk1 mutants have reduced virulence and are more susceptible to antibiotics, polyP synthesis and particularly PPK1, is a good target for the design of molecules with anti-virulence and anti-persistence properties.

Clinical utilization of genomics data produced by the international Pseudomonas aeruginosa consortium

DEFF Research Database (Denmark)

Freschi, Luca; Jeukens, Julie; Kukavica-Ibrulj, Irena

2015-01-01

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 a...... 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....

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

DEFF Research Database (Denmark)

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

2014-01-01

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

PARTIAL PURIFICATION AND CHARACTERIZATION OF ALKALOPHILIC PROTEASE FROM PSEUDOMONAS AERUGINOSA

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R. Satheeskumar

2013-10-01

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

Crystallization and preliminary X-ray crystallographic analysis of peptide deformylase from Pseudomonas aeruginosa.

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Kim, Hyung-Wook; Han, Byung Woo; Yoon, Hye-Jin; Yang, Jin Kuk; Lee, Byung Il; Lee, Hyung Ho; Ahn, Hyung Jun; Suh, Se Won

2002-10-01

Peptide deformylase (PDF) from the pathogenic bacterium Pseudomonas aeruginosa has been overexpressed in Escherichia coli and crystallized in the presence of its inhibitor actinonin at 297 K using polyethylene glycol (PEG) 4000 as a precipitant. The diffraction limit and the spot shape of the crystals could be slightly improved by the crystal annealing/dehydration procedure. X-ray diffraction data to 1.85 A have been collected using synchrotron radiation. The crystal belongs to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 68.75, b = 74.46, c = 77.18 A. The asymmetric unit contains two subunits of peptide deformylase, with a corresponding crystal volume per protein mass (V(M)) of 2.45 A(3) Da(-1) and a solvent content of 49.8%.

Nitrous oxide production in sputum from cystic fibrosis patients with chronic Pseudomonas aeruginosa lung infection.

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Mette Kolpen

Full Text Available Chronic lung infection by Pseudomonas aeruginosa is the major severe complication in cystic fibrosis (CF patients, where P. aeruginosa persists and grows in biofilms in the endobronchial mucus under hypoxic conditions. Numerous polymorphonuclear leukocytes (PMNs surround the biofilms and create local anoxia by consuming the majority of O2 for production of reactive oxygen species (ROS. We hypothesized that P. aeruginosa acquires energy for growth in anaerobic endobronchial mucus by denitrification, which can be demonstrated by production of nitrous oxide (N2O, an intermediate in the denitrification pathway. We measured N2O and O2 with electrochemical microsensors in 8 freshly expectorated sputum samples from 7 CF patients with chronic P. aeruginosa infection. The concentrations of NO3(- and NO2(- in sputum were estimated by the Griess reagent. We found a maximum median concentration of 41.8 µM N2O (range 1.4-157.9 µM N2O. The concentration of N2O in the sputum was higher below the oxygenated layers. In 4 samples the N2O concentration increased during the initial 6 h of measurements before decreasing for approximately 6 h. Concomitantly, the concentration of NO3(- decreased in sputum during 24 hours of incubation. We demonstrate for the first time production of N2O in clinical material from infected human airways indicating pathogenic metabolism based on denitrification. Therefore, P. aeruginosa may acquire energy for growth by denitrification in anoxic endobronchial mucus in CF patients. Such ability for anaerobic growth may be a hitherto ignored key aspect of chronic P. aeruginosa infections that can inform new strategies for treatment and prevention.

Nitrous oxide production in sputum from cystic fibrosis patients with chronic Pseudomonas aeruginosa lung infection.

Science.gov (United States)

Kolpen, Mette; Kühl, Michael; Bjarnsholt, Thomas; Moser, Claus; Hansen, Christine Rønne; Liengaard, Lars; Kharazmi, Arsalan; Pressler, Tanja; Høiby, Niels; Jensen, Peter Østrup

2014-01-01

Chronic lung infection by Pseudomonas aeruginosa is the major severe complication in cystic fibrosis (CF) patients, where P. aeruginosa persists and grows in biofilms in the endobronchial mucus under hypoxic conditions. Numerous polymorphonuclear leukocytes (PMNs) surround the biofilms and create local anoxia by consuming the majority of O2 for production of reactive oxygen species (ROS). We hypothesized that P. aeruginosa acquires energy for growth in anaerobic endobronchial mucus by denitrification, which can be demonstrated by production of nitrous oxide (N2O), an intermediate in the denitrification pathway. We measured N2O and O2 with electrochemical microsensors in 8 freshly expectorated sputum samples from 7 CF patients with chronic P. aeruginosa infection. The concentrations of NO3(-) and NO2(-) in sputum were estimated by the Griess reagent. We found a maximum median concentration of 41.8 µM N2O (range 1.4-157.9 µM N2O). The concentration of N2O in the sputum was higher below the oxygenated layers. In 4 samples the N2O concentration increased during the initial 6 h of measurements before decreasing for approximately 6 h. Concomitantly, the concentration of NO3(-) decreased in sputum during 24 hours of incubation. We demonstrate for the first time production of N2O in clinical material from infected human airways indicating pathogenic metabolism based on denitrification. Therefore, P. aeruginosa may acquire energy for growth by denitrification in anoxic endobronchial mucus in CF patients. Such ability for anaerobic growth may be a hitherto ignored key aspect of chronic P. aeruginosa infections that can inform new strategies for treatment and prevention.

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

DEFF Research Database (Denmark)

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

2010-01-01

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

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

DEFF Research Database (Denmark)

Jochumsen, Nicholas; Liu, Yang; Molin, Søren

2011-01-01

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

Epidemic population structure of Pseudomonas aeruginosa: evidence for a clone that is pathogenic to the eye and that has a distinct combination of virulence factors

DEFF Research Database (Denmark)

Lomholt, J; Poulsen, Knud; Kilian, Mogens

2001-01-01

The genetic structure of a population of Pseudomonas aeruginosa, isolated from patients with keratitis, endophthalmitis, and contact lens-associated red eye, contact lens storage cases, urine, ear, blood, lungs, wounds, feces, and the environment was determined by multilocus enzyme electrophoresis...

Ciprofloxacin susceptibility of Pseudomonas aeruginosa isolates from keratitis

DEFF Research Database (Denmark)

Lomholt, JA; Kilian, Mogens

2003-01-01

keratitis, endophthalmitis, contact lens associated red eye (CLARE), and contact lens storage cases showed MIC values below 1 mg/l. Several allelic forms of gyrA and a single variation in the mexR gene product were detected in 10 ciprofloxacin susceptible strains. CONCLUSIONS: The vast majority of eye......AIM: To examine the ciprofloxacin susceptibility of 106 Pseudomonas aeruginosa eye isolates from the United Kingdom, Denmark, India, the United States, and Australia, and to determine the molecular mechanisms of resistance. METHODS: Ciprofloxacin susceptibility was tested by an agar dilution method...... isolates of P aeruginosa from European countries are fully susceptible to ciprofloxacin and the concentration of ciprofloxacin eye drops used for local treatment (3000 mg/l) exceeds MIC values for strains recorded as resistant. Mutations in more than one target gene were associated with higher MIC values....

Ciprofloxacin susceptibility of Pseudomonas aeruginosa isolates from keratitis

DEFF Research Database (Denmark)

Lomholt, JA; Kilian, Mogens

2003-01-01

AIM: To examine the ciprofloxacin susceptibility of 106 Pseudomonas aeruginosa eye isolates from the United Kingdom, Denmark, India, the United States, and Australia, and to determine the molecular mechanisms of resistance. METHODS: Ciprofloxacin susceptibility was tested by an agar dilution method...... keratitis, endophthalmitis, contact lens associated red eye (CLARE), and contact lens storage cases showed MIC values below 1 mg/l. Several allelic forms of gyrA and a single variation in the mexR gene product were detected in 10 ciprofloxacin susceptible strains. CONCLUSIONS: The vast majority of eye...... isolates of P aeruginosa from European countries are fully susceptible to ciprofloxacin and the concentration of ciprofloxacin eye drops used for local treatment (3000 mg/l) exceeds MIC values for strains recorded as resistant. Mutations in more than one target gene were associated with higher MIC values....

Face Masks and Cough Etiquette Reduce the Cough Aerosol Concentration of Pseudomonas aeruginosa in People with Cystic Fibrosis.

Science.gov (United States)

Wood, Michelle E; Stockwell, Rebecca E; Johnson, Graham R; Ramsay, Kay A; Sherrard, Laura J; Jabbour, Nassib; Ballard, Emma; O'Rourke, Peter; Kidd, Timothy J; Wainwright, Claire E; Knibbs, Luke D; Sly, Peter D; Morawska, Lidia; Bell, Scott C

2018-02-01

People with cystic fibrosis (CF) generate Pseudomonas aeruginosa in droplet nuclei during coughing. The use of surgical masks has been recommended in healthcare settings to minimize pathogen transmission between patients with CF. To determine if face masks and cough etiquette reduce viable P. aeruginosa aerosolized during coughing. Twenty-five adults with CF and chronic P. aeruginosa infection were recruited. Participants performed six talking and coughing maneuvers, with or without face masks (surgical and N95) and hand covering the mouth when coughing (cough etiquette) in an aerosol-sampling device. An Andersen Cascade Impactor was used to sample the aerosol at 2 meters from each participant. Quantitative sputum and aerosol bacterial cultures were performed, and participants rated the mask comfort levels during the cough maneuvers. During uncovered coughing (reference maneuver), 19 of 25 (76%) participants produced aerosols containing P. aeruginosa, with a positive correlation found between sputum P. aeruginosa concentration (measured as cfu/ml) and aerosol P. aeruginosa colony-forming units. There was a reduction in aerosol P. aeruginosa load during coughing with a surgical mask, coughing with an N95 mask, and cough etiquette compared with uncovered coughing (P masks during coughing; yet, participants rated the surgical masks as more comfortable (P = 0.013). Cough etiquette provided approximately half the reduction of viable aerosols of the mask interventions during voluntary coughing. Talking was a low viable aerosol-producing activity. Face masks reduce cough-generated P. aeruginosa aerosols, with the surgical mask providing enhanced comfort. Cough etiquette was less effective at reducing viable aerosols.

Hyperbaric oxygen sensitizes anoxic Pseudomonas aeruginosa biofilm to ciprofloxacin

DEFF Research Database (Denmark)

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

2017-01-01

Chronic Pseudomonas aeruginosa lung infection is characterized by the presence of endobronchial antibiotic-tolerant biofilm subject to strong oxygen (O2) depletion due to the activity of surrounding polymorphonuclear leukocytes. The exact mechanisms affecting the antibiotic susceptibility...... metabolism activity and the endogenous formation of reactive O2 radicals (ROS). In this study we aimed to apply hyperbaric oxygen treatment (HBOT) in order to sensitize anoxic P. aeruginosa agarose-biofilms established to mimic situations with intense O2 consumption by the host response in the cystic...... fibrosis (CF) lung. Application of HBOT resulted in enhanced bactericidal activity of ciprofloxacin at clinically relevant durations and was accompanied by indications of restored aerobic respiration, involvement of endogenous lethal oxidative stress and increased bacterial growth. The findings highlight...

Development of Topical Treatment for Pseudomonas aeruginosa Wound Infections by Quorum-Sensing Inhibitors Mediated by Poly(amidoamine) (PAMAM) Dendrimers

Science.gov (United States)

2013-01-01

dendrimers would provide added benefits as a delivery vehicle of QSI compounds to inhibit PA biofilms, by both increasing the transport of QSI as drug...Pseudomonas aeruginosa Wound Infections by Quorum-Sensing Inhibitors Mediated by Poly(amidoamine) (PAMAM) Dendrimers PRINCIPAL INVESTIGATOR...Development of Topical Treatment for Pseudomonas aeruginosa Wound Infections by Quorum-Sensing Inhibitors Mediated by Poly(amidoamine) (PAMAM) Dendrimers

The Oxidative Stress Agent Hypochlorite Stimulates c-di-GMP Synthesis and Biofilm Formation in Pseudomonas aeruginosa

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Nikola Strempel

2017-11-01

Full Text Available The opportunistic human pathogen Pseudomonas aeruginosa is able to survive under a variety of often harmful environmental conditions due to a multitude of intrinsic and adaptive resistance mechanisms, including biofilm formation as one important survival strategy. Here, we investigated the adaptation of P. aeruginosa PAO1 to hypochlorite (HClO, a phagocyte-derived host defense compound and frequently used disinfectant. In static biofilm assays, we observed a significant enhancement in initial cell attachment in the presence of sublethal HClO concentrations. Subsequent LC-MS analyses revealed a strong increase in cyclic-di-GMP (c-di-GMP levels suggesting a key role of this second messenger in HClO-induced biofilm development. Using DNA microarrays, we identified a 26-fold upregulation of ORF PA3177 coding for a putative diguanylate cyclase (DGC, which catalyzes the synthesis of the second messenger c-di-GMP – an important regulator of bacterial motility, sessility and persistence. This DGC PA3177 was further characterized in more detail demonstrating its impact on P. aeruginosa motility and biofilm formation. In addition, cell culture assays attested a role for PA3177 in the response of P. aeruginosa to human phagocytes. Using a subset of different mutants, we were able to show that both Pel and Psl exopolysaccharides are effectors in the PA3177-dependent c-di-GMP network.

Evolutionary conservation of essential and highly expressed genes in Pseudomonas aeruginosa

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Scharfe Maren

2010-04-01

Full Text Available Abstract Background The constant increase in development and spread of bacterial resistance to antibiotics poses a serious threat to human health. New sequencing technologies are now on the horizon that will yield massive increases in our capacity for DNA sequencing and will revolutionize the drug discovery process. Since essential genes are promising novel antibiotic targets, the prediction of gene essentiality based on genomic information has become a major focus. Results In this study we demonstrate that pooled sequencing is applicable for the analysis of sequence variations of strain collections with more than 10 individual isolates. Pooled sequencing of 36 clinical Pseudomonas aeruginosa isolates revealed that essential and highly expressed proteins evolve at lower rates, whereas extracellular proteins evolve at higher rates. We furthermore refined the list of experimentally essential P. aeruginosa genes, and identified 980 genes that show no sequence variation at all. Among the conserved nonessential genes we found several that are involved in regulation, motility and virulence, indicating that they represent factors of evolutionary importance for the lifestyle of a successful environmental bacterium and opportunistic pathogen. Conclusion The detailed analysis of a comprehensive set of P. aeruginosa genomes in this study clearly disclosed detailed information of the genomic makeup and revealed a large set of highly conserved genes that play an important role for the lifestyle of this microorganism. Sequencing strain collections enables for a detailed and extensive identification of sequence variations as potential bacterial adaptation processes, e.g., during the development of antibiotic resistance in the clinical setting and thus may be the basis to uncover putative targets for novel treatment strategies.

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

DEFF Research Database (Denmark)

Yang, Liang; Nilsson, Martin; Gjermansen, Morten

2009-01-01

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

Pseudo-outbreak of pseudomonas aeruginosa in HIV-infected patients undergoing fiberoptic bronchoscopy

DEFF Research Database (Denmark)

Kolmos, H J; Lerche, A; Kristoffersen, Kirsten Lydia

1994-01-01

Pseudomonas aeruginosa was isolated from bronchoalveolar lavage fluid from 8 consecutive patients undergoing bronchoscopy at an infectious diseases unit. None of the patients developed signs of respiratory tract infection that could be ascribed to the organism. The source of contamination...

Catabolite repression and nitrogen control of allantoin-degrading enzymes in Pseudomonas aeruginosa

NARCIS (Netherlands)

Janssen, D.B.; Drift, C. van der

1983-01-01

The formation of the allantoin-degrading enzymes allantoinase, allantoicase and ureidoglycolase in Pseudomonas aeruginosa was found to be regulated by induction, catabolite repression and nitrogen control. Induction was observed when urate, allantoin or allantoate were included in the growth medium,

Enterobactin-mediated iron transport in Pseudomonas aeruginosa.

Science.gov (United States)

Poole, K; Young, L; Neshat, S

1990-01-01

A pyoverdine-deficient strain of Pseudomonas aeruginosa was unable to grow in an iron-deficient minimal medium in the presence of the nonmetabolizable iron chelator ethylene diamine-di(omega-hydroxyphenol acetic acid) (EDDHA), although addition of enterobactin to EDDHA-containing minimal media did restore growth of the pyoverdine-deficient P. aeruginosa. Consistent with the apparent ability of enterobactin to provide iron to P. aeruginosa, enterobactin-dependent 55Fe3+ uptake was observed in cells of P. aeruginosa previously grown in an iron-deficient medium containing enterobactin (or enterobactin-containing Escherichia coli culture supernatant). This uptake was energy dependent, was observable at low concentrations (60 nM) of FeCl3, and was absent in cells cultured without enterobactin. A novel protein with a molecular weight of approximately 80,000 was identified in the outer membranes of cells grown in iron-deficient minimal medium containing enterobactin, concomitant with the induction of enterobactin-dependent iron uptake. A Tn501 insertion mutant lacking this protein was isolated and shown to be deficient in enterobactin-mediated iron transport at 60 nM FeCl3, although it still exhibited enterobactin-dependent growth in iron-deficient medium containing EDDHA. It was subsequently observed that the mutant was, however, capable of enterobactin-mediated iron transport at much higher concentrations (600 nM) of FeCl3. Indeed, enterobactin-dependent iron uptake at this concentration of iron was observed in both the mutant and parent strains irrespective of whether they had been cultured in the presence of enterobactin.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:2174865

A laminar flow model of aerosol survival of epidemic and non-epidemic strains of Pseudomonas aeruginosa isolated from people with cystic fibrosis

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Denton Miles

2008-06-01

Full Text Available Abstract Background Cystic fibrosis (CF is an inherited multi-system disorder characterised by chronic airway infection with pathogens such as Pseudomonas aeruginosa. Acquisition of P. aeruginosa by patients with CF is usually from the environment, but recent studies have demonstrated patient to patient transmission of certain epidemic strains, possibly via an airborne route. This study was designed to examine the survival of P. aeruginosa within artificially generated aerosols. Results Survival was effected by the solution used for aerosol generation. Within the aerosols it was adversely affected by an increase in air temperature. Both epidemic and non-epidemic strains of P. aeruginosa were able to survive within the aerosols, but strains expressing a mucoid phenotype had a survival advantage. Conclusion This would suggest that segregating individuals free of P. aeruginosa from those with chronic P. aeruginosa infection who are more likely to be infected with mucoid strains may help reduce the risk of cross-infection. Environmental factors also appear to influence bacterial survival. Warming and drying the air within clinical areas and avoidance of humidification devices may also be beneficial in reducing the risk of cross-infection.

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 Isolamento de cepas de Pseudomonas aeruginosa provenientes do meio ambiente e de equipos dentarios em clinicas dentarias em Barretos, São Paulo, Brasil; analises da susceptibilidade das cepas a drogas antimicrobianas

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Ana Claudia de Oliveira

2008-09-01

Full Text Available 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.Uma ampla variedade de patógenos oportunistas tem sido detectadas nos tubos de alimentação de água dos equipos odontológicos, particularmente no biofilme formado na superfície do tubo. Entre os patógenos oportunistas encontrados nos tubos de água, Pseudomonas aeruginosa é reconhecida como uma das principais causadoras de infecções nosocomiais. Foram coletadas 160 amostras de água e 200 amostras de fomites em quarenta clinicas odontológicas na cidade de Barretos, São Paulo, Brasil, durante o período de Janeiro a Julho de 2005. Setenta e seis cepas de P. aeruginosa, isoladas a partir dos fomites (5 cepas e das amostras de água (71 cepas, foram analisadas quanto à susceptibilidade à seis drogas antimicrobianas freqüentemente utilizadas para o tratamento de infecções provocadas por P. aeruginosa. As principais suscetibilidades observadas foram para a

Potato seed dressing with Pseudomonas aeruginosa strain RZ9 enhances yield and reduces black scurf

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Moncef MRABET

2015-09-01

Full Text Available A rhizospheric strain RZ9 of Pseudomonas aeruginosa was assessed for in-vitro growth inhibition of Rhizoctonia solani and effectiveness to control black scurf on potatoes (Solanum tuberosum L. of the cultivars Spunta and Nicola, in greenhouse and field experiments. The strain RZ9 inhibited R. solani mycelial growth by more than 60% and completely inhibited the germination of sclerotia from infested potato tubers in in-vitro tests. In greenhouse assays, seed potato treatment with RZ9 cell suspension increased stem length, decreased the relative weight of infected potato tubers (by 67%, and increased the potato yield (by 16% compared to pathogen-inoculated plants for both potato cultivars. In field trials conducted on sandy soils during 2012 and 2013, strain RZ9 reduced black scurf incidence and increased potato yield by an average of 5.3 t ha-1 for ′Spunta′ and 5 t ha-1 for ′Nicola′. This study showed that the selected strain of P. aeruginosa is an efficient bacterium for enhancing yield and reducing black scurf of field-grown potatoes.

Structure and activity of the Pseudomonas aeruginosa hotdog-fold thioesterases PA5202 and PA2801.

Science.gov (United States)

Gonzalez, Claudio F; Tchigvintsev, Anatoli; Brown, Greg; Flick, Robert; Evdokimova, Elena; Xu, Xiaohui; Osipiuk, Jerzy; Cuff, Marianne E; Lynch, Susan; Joachimiak, Andrzej; Savchenko, Alexei; Yakunin, Alexander F

2012-06-15

The hotdog fold is one of the basic protein folds widely present in bacteria, archaea and eukaryotes. Many of these proteins exhibit thioesterase activity against fatty acyl-CoAs and play important roles in lipid metabolism, cellular signalling and degradation of xenobiotics. The genome of the opportunistic pathogen Pseudomonas aeruginosa contains over 20 genes encoding predicted hotdog-fold proteins, none of which have been experimentally characterized. We have found that two P. aeruginosa hotdog proteins display high thioesterase activity against 3-hydroxy-3-methylglutaryl-CoA and glutaryl-CoA (PA5202), and octanoyl-CoA (PA2801). Crystal structures of these proteins were solved (at 1.70 and 1.75 Å for PA5202 and PA2801 respectively) and revealed a hotdog fold with a potential catalytic carboxylate residue located on the long α-helix (Asp(57) in PA5202 and Glu(35) in PA2801). Alanine residue replacement mutagenesis of PA5202 identified four residues (Asn(42), Arg(43), Asp(57) and Thr(76)) that are critical for its activity and are located in the active site. A P. aeruginosa PA5202 deletion strain showed an increased secretion of the antimicrobial pigment pyocyanine and an increased expression of genes involved in pyocyanin biosynthesis, suggesting a functional link between PA5202 activity and pyocyanin production. Thus the P. aeruginosa hotdog thioesterases PA5202 and PA2801 have similar structures, but exhibit different substrate preferences and functions.

Molecular cloning and characterization of the recA gene of Pseudomonas aeruginosa PAO

Energy Technology Data Exchange (ETDEWEB)

Kokjohn, T.A.; Miller, R.V.

1985-08-01

The recA gene of Pseudomonas aeruginosa PAO has been isolated and introduced into Escherichia coli K-12. Resistance to killing by UV irradiation was restored in several RecA-E. coli K-12 hosts by the P. aeruginosa gene, as was resistance to methyl methanesulfonate. Recombination proficiency was also restored, as measured by HfrH-mediated conjugation and by the ability to propagate Fec-phage lambda derivatives. The cloned P. aeruginosa recA gene restored both spontaneous and mitomycin C-stimulated induction of lambda prophage in lysogens of a recA strain of E. coli K-12.

Biosynthesis of Gold Nanoparticles Using Pseudomonas Aeruginosa

International Nuclear Information System (INIS)

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

2007-01-01

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

Extracellular toxins of pseudomonas aeruginosa. Pt. 4

International Nuclear Information System (INIS)

Obernesser, H.J.; Doering, G.

1982-01-01

A sensitive and specific solid phase radioimmunoassay (RIA) for detection of the elastase (Ela) of Pseudomonas aeruginosa (PA) was developed and the RIA was used to assay 10 PA strains of various origin and serotype. A great strain variability of Ela production was found which different from 94.1 to 0.1 μg per ml of culture supernatant fluid (CSF). The Ela and alkaline protease (AP) concentrations were converted to proteolytic activity and combined. The sum of the calculated enzymatic values of Ela and AP correlated well with the experimentally determined values of total proteolytic activity of the CSF. (orig.) [de

THE PERFORMANCE OF A LONG-TERM ANTIBACTERIAL THERAPY IN CHILDREN WITH CYSTIC FIBROSIS DURING PRIMARY PLATING OF PSEUDOMONAS AERUGINOSA

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О. I. Simonova

2014-01-01

Full Text Available Background: A long-term plating of Pseudomonas aeruginosa in patients with cystic fibrosis is a sign of damage of the lung tissues with rapid progression of the disease and decrease in a respiratory function. The early pathogen detection is necessary for the timely prescription of an antibiotic for the purpose of a complete eradication of P. aeruginosa. Objective: Our aim was to determine the efficiency and safety of an inhalation form of the colistimethate sodium antibiotic in children with cystic fibrosis during the initial detection of P. aeruginosa. Methods: In a retrospective continuous study it was analyzed the results of inhalation use of the colistimethate sodium in a dose of 2 million IU/day in children with moderate cystic fibrosis with newly diagnosed P. aeruginosa. Results: The analysis included data of 25 children at the age of 2–10 years, 17 of them were treated with colistimethate sodium for 6 months, 8 — for 12 months. P. aeruginosa eradication was detected in 22 (88% children. Children, who received antibiotic therapy for 6 months, at the end of the treatment showed an increase in forced expiratory volume for the 1st second (FEV-1 from 67.1 ± 2.2 to 80.4 ± 1.9% (р = 0.012, but in 3 months without inhalations there was a decrease in indicator values (to 75.9 ± 5.7%; p = 0.069. With the duration of inhalations of 12 months, the value FEV-1 indicator also increased: from 65.9 ± 3.8 to 81.5 ± 3.1% (р = 0.011. However, in the following 3 months without therapy these children did not have any significant decrease in FEV-1 (80.6 ± 3.4%; р = 0.073. There were no allergic reactions during the treatment; bronchospasm was observed in one child. For the entire period of management any P. aeruginosa strain, resistant to the colistimethate sodium, was not revealed. Conclusion: During the initial detection of P. aeruginosa in children with cystic fibrosis, a long-term therapy, including inhalations with colistimethate sodium

Environmental and molecular characterization of systems which affect genome alteration in pseudomonas aeruginosa

International Nuclear Information System (INIS)

Miller, R.V.; Kokjohn, T.A.; Sayler, G.S.

1990-01-01

Pseudomonas aeruginosa is used as a model organism to study genome alteration in freshwater microbial populations and horizontal gene transmission by both transduction and conjugation has been demonstrated. The studies have also provided data which suggest that intracellular genome instability may be increased in the aquatic environment as a result of stresses encountered by the cell in this habitat. The role of the P. aeruginosa recA analog in regulating genome instability is also addressed

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

NARCIS (Netherlands)

Neut, D; Hendriks, JGE; van Horn, Jim R.; van der Mei, HC; Busscher, HJ

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

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

Science.gov (United States)

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

1997-12-18

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

Crystallization and preliminary crystal structure analysis of the ligand-binding domain of PqsR (MvfR), the Pseudomonas quinolone signal (PQS) responsive quorum-sensing transcription factor of Pseudomonas aeruginosa

International Nuclear Information System (INIS)

Xu, Ningna; Yu, Shen; Moniot, Sébastien; Weyand, Michael; Blankenfeldt, Wulf

2012-01-01

The ligand-binding domain of the transcription factor PqsR from P. aeruginosa has been crystallized and initial phases have been obtained using SAD data from seleno-l-methionine-labelled crystals. The opportunistic bacterial pathogen Pseudomonas aeruginosa employs three transcriptional regulators, LasR, RhlR and PqsR, to control the transcription of a large subset of its genes in a cell-density-dependent process known as quorum sensing. Here, the recombinant production, crystallization and structure solution of the ligand-binding domain of PqsR (MvfR), the LysR-type transcription factor that responds to the Pseudomonas quinolone signal (PQS), a quinolone-based quorum-sensing signal that is unique to P. aeruginosa and possibly a small number of other bacteria, is reported. PqsR regulates the expression of many virulence genes and may therefore be an interesting drug target. The ligand-binding domain (residues 91–319) was produced as a fusion with SUMO, and hexagonal-shaped crystals of purified PqsR-91–319 were obtained using the vapour-diffusion method. Crystallization in the presence of a PQS precursor allowed data collection to 3.25 Å resolution on a synchrotron beamline, and initial phases have been obtained using single-wavelength anomalous diffraction data from seleno-l-methionine-labelled crystals, revealing the space group to be P6 5 22, with unit-cell parameters a = b = 116–120, c = 115–117 Å

Structural and Molecular Mechanism of CdpR Involved in Quorum-Sensing and Bacterial Virulence in Pseudomonas aeruginosa.

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Jingru Zhao

2016-04-01

Full Text Available Although quorum-sensing (QS systems are important regulators of virulence gene expression in the opportunistic human pathogen Pseudomonas aeruginosa, their detailed regulatory mechanisms have not been fully characterized. Here, we show that deletion of PA2588 resulted in increased production of pyocyanin and biofilm, as well as enhanced pathogenicity in a mouse model. To gain insights into the function of PA2588, we performed a ChIP-seq assay and identified 28 targets of PA2588, including the intergenic region between PA2588 and pqsH, which encodes the key synthase of Pseudomonas quinolone signal (PQS. Though the C-terminal domain was similar to DNA-binding regions of other AraC family members, structural studies revealed that PA2588 has a novel fold at the N-terminal region (NTR, and its C-terminal HTH (helix-turn-helix domain is also unique in DNA recognition. We also demonstrated that the adaptor protein ClpS, an essential regulator of ATP-dependent protease ClpAP, directly interacted with PA2588 before delivering CdpR to ClpAP for degradation. We named PA2588 as CdpR (ClpAP-degradation and pathogenicity Regulator. Moreover, deletion of clpP or clpS/clpA promotes bacterial survival in a mouse model of acute pneumonia infection. Taken together, this study uncovered that CdpR is an important QS regulator, which can interact with the ClpAS-P system to regulate the expression of virulence factors and pathogenicity.

Molecular Determinants of the Thickened Matrix in a Dual-Species Pseudomonas aeruginosa and Enterococcus faecalis Biofilm.

Science.gov (United States)

Lee, Keehoon; Lee, Kang-Mu; Kim, Donggeun; Yoon, Sang Sun

2017-11-01

have reported that microbes in polymicrobial biofilms interact with each other and that the bacterial interactions result in elevated virulence, in terms of factors, such as infectivity and antibiotic resistance. Pseudomonas aeruginosa and Enterococcus faecalis are frequently isolated pathogens in chronic biofilm infections. Nevertheless, while both bacteria are known to be agents of numerous nosocomial infections and can cause serious diseases, interactions between the bacteria in biofilms have rarely been examined. In this investigation, we aimed to characterize P. aeruginosa and E. faecalis dual-species biofilms and to determine the molecular factors that cause synergistic effects, especially on the matrix thickening of the biofilm. We suspect that our findings will contribute to the development of more efficient methods for eradicating polymicrobial biofilm infections. Copyright © 2017 American Society for Microbiology.

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

Science.gov (United States)

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

2016-08-01

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

Study of Microbial Contamination of the Public Swimming Pools with Escherichia coli and Pseudomonas aeruginosa and Their Physical Parameters in Kermanshah, Iran

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Afsaneh Haghmorad Korasti

2016-09-01

Full Text Available Background and Objectives: Public swimming pools' waters are contaminated with a wide variety of pathogenic microorganisms and are a suitable environment for transmission of different diseases. The aim of this study was to investigate the microbial contamination of the public swimming pools' waters with Escherichia coli and Pseudomonas aeruginosa and to determine certain parameters such as residual chlorine, pH, temperature and turbidity in these pools' waters in Kermanshah. In this descriptive, cross-sectional study, 129 water samples were taken from all active pools in Kermanshah and their bacteriologic and physicochemical properties were investigated. Phosphatase alkaline (PHO-A gene was used for molecular confirmation of E. coli isolates, and exotoxin A (ETA gene in PCR was employed to confirm pathogenicity of P. aeruginosa isolates. Data were analyzed by chi-square and t-test. p0.05. Conclusion: The results of this study indicated that appropriate amount of residual chlorine caused reduction in microbial contamination in the public swimming pools' waters in Kermanshah.

Oxygen regulation of nitrate uptake in denitrifying Pseudomonas aeruginosa.

OpenAIRE

Hernandez, D; Rowe, J J

1987-01-01

Oxygen had an immediate and reversible inhibitory effect on nitrate respiration by denitrifying cultures of Pseudomonas aeruginosa. Inhibition of nitrate utilization by oxygen appeared to be at the level of nitrate uptake, since nitrate reduction to nitrite in cell extracts was not affected by oxygen. The degree of oxygen inhibition was dependent on the concentration of oxygen, and increasing nitrate concentrations could not overcome the inhibition. The inhibitory effect of oxygen was maximal...

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

Science.gov (United States)

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

2007-06-01

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

Biofilm production by clinical isolates of Pseudomonas aeruginosa and structural changes in LasR protein of isolates non biofilm-producing

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Jailton Lobo da Costa Lima

2018-03-01

Full Text Available Introduction: Biofilm production is an important mechanism for the survival of Pseudomonas aeruginosa and its relationship with antimicrobial resistance represents a challenge for patient therapeutics. P. aeruginosa is an opportunistic pathogen frequently associated to nosocomial infections, especially in imunocompromised hosts. Objectives: Analyze the phenotypic biofilm production in P. aeruginosa isolates, describe clonal profiles, and analyze quorum sensing (QS genes and the occurrence of mutations in the LasR protein of non-biofilm producing isolates. Methods: Isolates were tested for biofilm production by measuring cells adherence to the microtiter plates. Clonal profile analysis was carried out through ERIC-PCR, QS genes were by specific PCR. Results: The results showed that 77.5% of the isolates were considered biofilm producers. The results of genotyping showed 38 distinct genetic profiles. As for the occurrence of the genes, 100% of the isolates presented the lasR, rhlI and rhlR genes, and 97.5%, presented the lasI gene. In this study nine isolates were not biofilm producers. However, all presented the QS genes. Amplicons related to genes were sequenced in three of the nine non-biofilm-producing isolates (all presenting different genetic similarity profile and aligned to the sequences of those genes in P. aeruginosa strain PAO1 (standard biofilm-producing strain. Alignment analysis showed an insertion of three nucleotides (T, C and G causing the addition of an amino acid valine in the sequence of the LasR protein, in position 53. Conclusion: The modeling of the resulting LasR protein showed a conformational change in its structure, suggesting that this might be the reason why these isolates are unable to produce biofilm. Keywords: Pseudomonas aeruginosa, Biofilm, Multiresistance, Quorum sensing (QS

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

DEFF Research Database (Denmark)

Andersen, A S; Joergensen, B; Bjarnsholt, T

2010-01-01

Maggot debridement therapy (MDT) is widely used for debridement of chronic infected wounds; however, for wounds harbouring specific bacteria limited effect or failure of the treatment has been described. Here we studied the survival of Lucilia sericata maggots encountering Pseudomonas aeruginosa...... PAO1 in a simple assay with emphasis on the quorum-sensing (QS)-regulated virulence. The maggots were challenged with GFP-tagged P. aeruginosa wild-type (WT) PAO1 and a GFP-tagged P. aeruginosa DeltalasR rhlR (DeltaRR) QS-deficient mutant in different concentrations. Maggots were killed...

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

NARCIS (Netherlands)

Flemming, CA; Palmer, RJ; Arrage, AA; van der Mei, H.C.; White, DC

1999-01-01

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

Fluorescence-Based Reporter for Gauging Cyclic Di-GMP Levels in Pseudomonas aeruginosa

DEFF Research Database (Denmark)

Rybtke, Morten T.; Borlee, Bradley R.; Murakami, Keiji

2012-01-01

The increased tolerance toward the host immune system and antibiotics displayed by biofilm-forming Pseudomonas aeruginosa and other bacteria in chronic infections such as cystic fibrosis bronchopneumonia is of major concern. Targeting of biofilm formation is believed to be a key aspect in the dev...

Resistance of Pseudomonas aeruginosa isolates to hydrogel contact lens disinfection correlates with cytotoxic activity.

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Lakkis, C; Fleiszig, S M

2001-04-01

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

THE REDOX PATHWAY OF Pseudomonas aeruginosa CYTOCHROME C BIOGENESIS

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Eva Di Silvio

2012-06-01

Full Text Available Cytochrome c contains heme covalently bound to the polypeptide chain through two thioether bonds between the heme vinyl groups and the two cysteines of the conserved heme- binding motif of the apoprotein. Surprisingly, the biochemical events leading to the synthesis of the functional holoprotein in the cell are largely unknown. In the human pathogen Pseudomonas aeruginosa, the biogenesis of Cytc is mediated by a group of membrane or membrane-anchored proteins (CcmABCDEFGHI, exposing their active site to the periplasm. The Ccm proteins involved in the necessary reduction of apoCyt disulfide bond are CcmG and CcmH. Here we present the structural and functional characterization of these two redox-active proteins. We determined the crystal structure of CcmG, both in the oxidized and the reduced state. CcmG is a membrane-anchored thioredoxinlike protein acting as a mild reductant in the redox pathway of Cytc biogenesis. The 3D structure of the soluble periplasmic domain of CcmH revealed that it adopts a peculiar three-helix bundle fold that is different from that of canonical thiol-oxidoreductases. Moreover, we present protein-protein interaction experiments aiming at elucidating the molecular mechanism of the reduction of apoCyt disulfide bond for heme attachment in vivo. On the basis of the structural and functional data on CcmG, CcmH and their interactions, we propose an assembly line for Cytc biogenesis in P. aeruginosa in which reduced CcmH specifically recognizes, binds and reduces oxidized apoCyt via the formation of a mixed disulfide complex, which is subsequently resolved by CcmG.

Ocorrência de linhagens de Pseudomonas aeruginosa cloro resistentes em águas de diferentes origens = Ocurrence of chlorine resistant strains of Pseudomonas aeruginosa from different water sources

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Glícia Maria Torres Calazans

2007-07-01

Full Text Available Pseudomonas aeruginosa é conhecida por sua versatilidade metabólica e extrema capacidade de adaptação a diferentes ambientes, inclusive aquáticos. Para desinfecção de águas, o cloro e agentes que contêm cloro continuam sendo os mais usados no mundo. O objetivo deste trabalho foi avaliar a resistência ao cloro de linhagens de P. aeruginosa, isoladas de amostras de águas de diversos ambientes. Foram testados diferentes tempos de contato (1, 5, 10, 20, 30 e 40 minutos e soluções aquosas de cloro, com concentrações definidascom base na legislação vigente no país para água potável: 0,5; 1,0 e 2,0 ppm. O teste de resistência ao cloro foi desenvolvido por meio da exposição direta das bactérias às soluções. Os resultados revelaram que P. aeruginosa, isoladas de diferentes fontes de água, têm ahabilidade de sobreviver a diferentes concentrações de cloro. Na concentração de 1 ppm, a maioria das linhagens não foi inibida. As linhagens mais resistentes ao cloro também apresentaram relação de multirresistência à maioria dos antibióticos testados.The nutritional versatility and the adaptability of Pseudomonas aeruginosa to different environments, including water, are well known. Chlorine and other chlorine agents are used as water disinfecting all around the world. The aim of this work was to evaluate the possible chlorine resistance amongst P. aeruginosa strains isolated from different aquatic sources by using different contact time (1, 5, 10, 20, 30 and 40 minutes in solutions with known chlorine concentrations according current legislation in the country to potable water: 0.5; 1.0 and 2.0 ppm. The chlorine resistance test was done by direct exposure of P. aeruginosa under a solution with known chlorine concentration. Results showed that P. aeruginosa strains isolated from different aquatic sources are able tosurvive in different chlorine concentrations. At 1 ppm, most of them were not inhibited. It was also observed

Explore the full thick layer of corneal transplantation in the treatment of pseudomonas aeruginosa corneal ulcer infection

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Xin Wang

2015-02-01

Full Text Available AIM: To explore the feasibility, safety and effect of the full-thickness lamellar keratoplasty for the treatment of pseudomonas aeruginosa corneal ulcer. METHODS: Based on a retrospective non-controlled study, 25 patients were given the full-thickness lamellar keratoplasty for clinical diagnosis of pseudomonas aeruginosa infection and corneal ulcer medication conventional anti-gram-negative bacteria. Routine follow-up were carried out at postoperative 1wk; 1, 3, 6, 12, 18mo to observe the situation of corneal epithelial healing, recurrent infection, immune rejection, graft transparency and best corrected visual acuity, etc. At the 6 and 12mo postoperative, corneal endothelial cell density was reexamined.RESULTS: No patients because of Descemet's membrane rupture underwent penetrating keratoplasty surgery: One only in cases of bacterial infection after 1mo, once again did not cultivate a culture of bacteria pseudomonas aeruginosa, and the remaining 24 cases average follow-up 14±6mo, corneal graft were transparent, the cure rate was 96%. At the sixth month after surgery, there were 16 cases of eye surgery best corrected visual acuity ≥4.5, of which 3 cases ≥4.8. At the sixth month after surgery, the average corneal endothelial cell density 2 425±278/mm2; At 12mo postoperatively, it was 2 257± 326/mm2.CONCLUSION: Full-thickness lamellar keratoplasty is an effective method of pseudomonas aeruginosa infection in the treatment of corneal ulcers, corneal drying material glycerol can be achieved by visual effects.

Polymorphonuclear leukocytes restrict growth of Pseudomonas aeruginosa in the lungs of cystic fibrosis patients

DEFF Research Database (Denmark)

Kragh, Kasper Nørskov; Alhede, Morten; Jensen, Peter Østrup

2014-01-01

Cystic fibrosis (CF) patients have increased susceptibility to chronic lung infections by Pseudomonas aeruginosa, but the ecophysiology within the CF lung during infections is poorly understood. The aim of this study was to elucidate the in vivo growth physiology of P. aeruginosa within lungs...... of chronically infected CF patients. A novel, quantitative peptide nucleic acid (PNA) fluorescence in situ hybridization (PNA-FISH)-based method was used to estimate the in vivo growth rates of P. aeruginosa directly in lung tissue samples from CF patients and the growth rates of P. aeruginosa in infected lungs...... in a mouse model. The growth rate of P. aeruginosa within CF lungs did not correlate with the dimensions of bacterial aggregates but showed an inverse correlation to the concentration of polymorphonuclear leukocytes (PMNs) surrounding the bacteria. A growth-limiting effect on P. aeruginosa by PMNs was also...

Epigenetic control of virulence gene expression in Pseudomonas aeruginosa by a LysR-type transcription regulator.

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Keith H Turner

2009-12-01

Full Text Available Phenotypic variation within an isogenic bacterial population is thought to ensure the survival of a subset of cells in adverse conditions. The opportunistic pathogen Pseudomonas aeruginosa variably expresses several phenotypes, including antibiotic resistance, biofilm formation, and the production of CupA fimbriae. Here we describe a previously unidentified bistable switch in P. aeruginosa. This switch controls the expression of a diverse set of genes, including aprA, which encodes the secreted virulence factor alkaline protease. We present evidence that bistable expression of PA2432, herein named bexR (bistable expression regulator, which encodes a LysR-type transcription regulator, controls this switch. In particular, using DNA microarrays, quantitative RT-PCR analysis, chromatin immunoprecipitation, and reporter gene fusions, we identify genes directly under the control of BexR and show that these genes are bistably expressed. Furthermore, we show that bexR is itself bistably expressed and positively autoregulated. Finally, using single-cell analyses of a GFP reporter fusion, we present evidence that positive autoregulation of bexR is necessary for bistable expression of the BexR regulon. Our findings suggest that a positive feedback loop involving a LysR-type transcription regulator serves as the basis for an epigenetic switch that controls virulence gene expression in P. aeruginosa.

Detection of multidrug-resistant Pseudomonas aeruginosa harboring bla GES-1 and bla GES-11 in Recife, Brazil

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Valdemir Vicente da Silva Júnior

Full Text Available Abstract INTRODUCTION: Pseudomonas aeruginosa, an important pathogen globally, presents several resistance mechanisms. This study aimed to investigate the presence of bla GES in clinical isolates of Pseudomonas aeruginosa obtained from various clinical specimens from patients admitted to three different hospitals in Recife, Brazil. The Guiana extended spectrum beta-lactamase (GES enzymes are responsible for conferring broad spectrum resistance to beta-lactam drugs, including the carbapenems. METHODS: A total of 100 carbapenem-resistant P. aeruginosa isolates underwent polymerase chain reaction (PCR testing to identify bla GES, bla KPC, bla SPM-1, bla IMP, and bla VIM. Additionally, PCR products positive for bla GES were sequenced. The clonal profiles of these same isolates were then determined by means of enterobacterial repetitive intergenic consensus (ERIC-PCR analysis. RESULTS: PCR analysis revealed that four isolates harbored bla GES; DNA sequencing showed that two harbored bla GES-1 and two bla GES-11. Beta-lactamase genes bla SPM-1, bla IMP, bla VIM, and bla KPC were investigated; none of these genes was detected. Automated susceptibility testing methods (Vitek®2, bioMérieux showed that the bla GES-1-positive isolates were only susceptible to polymyxin B. The patterns obtained with ERIC-PCR methods showed clonal relationship between the two isolates that harbored bla GES-11, whereas different clonal profiles were found in the isolates harboring bla GES-1. CONCLUSIONS: We detected the presence of bacterial isolates positive for two different variants of the enzyme GES in three different hospitals from Recife, Brazil. These enzymes have a great capacity for dissemination among Gram-negative bacteria and confer broad-spectrum resistance to beta-lactam antibiotics and to the carbapenems.

Detection of Pseudomonas aeruginosa in sputum headspace through volatile organic compound analysis

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Goeminne Pieter C

2012-10-01

Full Text Available Abstract Introduction Chronic pulmonary infection is the hallmark of Cystic Fibrosis lung disease. Searching for faster and easier screening may lead to faster diagnosis and treatment of Pseudomonas aeruginosa (P. aeruginosa. Our aim was to analyze and build a model to predict the presence of P. aeruginosa in sputa. Methods Sputa from 28 bronchiectatic patients were used for bacterial culturing and analysis of volatile compounds by gas chromatography–mass spectrometry. Data analysis and model building were done by Partial Least Squares Regression Discriminant analysis (PLS-DA. Two analysis were performed: one comparing P. aeruginosa positive with negative cultures at study visit (PA model and one comparing chronic colonization according to the Leeds criteria with P. aeruginosa negative patients (PACC model. Results The PA model prediction of P. aeruginosa presence was rather poor, with a high number of false positives and false negatives. On the other hand, the PACC model was stable and explained chronic P. aeruginosa presence for 95% with 4 PLS-DA factors, with a sensitivity of 100%, a positive predictive value of 86% and a negative predictive value of 100%. Conclusion Our study shows the potential for building a prediction model for the presence of chronic P. aeruginosa based on volatiles from sputum.

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

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Wendy E Kaman

Full Text Available Pseudomonas aeruginosa produces a number of proteases that are associated with virulence and disease progression. A substrate able to detect P. aeruginosa-specific proteolytic activity could help to rapidly alert clinicians to the virulence potential of individual P. aeruginosa strains. For this purpose we designed a set of P. aeruginosa-specific fluorogenic substrates, comprising fluorescence resonance energy transfer (FRET-labeled peptides, and evaluated their applicability to P. aeruginosa virulence in a range of clinical isolates. A FRET-peptide comprising three glycines (3xGly was found to be specific for the detection of P. aeruginosa proteases. Further screening of 97 P. aeruginosa clinical isolates showed a wide variation in 3xGly cleavage activity. The absence of 3xGly degradation by a lasI knock out strain indicated that 3xGly cleavage by P. aeruginosa could be quorum sensing (QS-related, a hypothesis strengthened by the observation of a strong correlation between 3xGly cleavage, LasA staphylolytic activity and pyocyanin production. Additionally, isolates able to cleave 3xGly were more susceptible to the QS inhibiting antibiotic azithromycin (AZM. In conclusion, we designed and evaluated a 3xGly substrate possibly useful as a simple tool to predict virulence and AZM susceptibility.

Imipenem, meropenem, or doripenem to treat patients with Pseudomonas aeruginosa ventilator-associated pneumonia.

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Luyt, Charles-Edouard; Aubry, Alexandra; Lu, Qin; Micaelo, Maïté; Bréchot, Nicolas; Brossier, Florence; Brisson, Hélène; Rouby, Jean-Jacques; Trouillet, Jean-Louis; Combes, Alain; Jarlier, Vincent; Chastre, Jean

2014-01-01

Only limited data exist on Pseudomonas aeruginosa ventilator-associated pneumonia (VAP) treated with imipenem, meropenem, or doripenem. Therefore, we conducted a prospective observational study in 169 patients who developed Pseudomonas aeruginosa VAP. Imipenem, meropenem, and doripenem MICs for Pseudomonas aeruginosa isolates were determined using Etests and compared according to the carbapenem received. Among the 169 isolates responsible for the first VAP episode, doripenem MICs were lower (Pimipenem and meropenem (MIC50s, 0.25, 2, and 0.38, respectively); 61%, 64%, and 70% were susceptible to imipenem, meropenem, and doripenem, respectively (P was not statistically significant). Factors independently associated with carbapenem resistance were previous carbapenem use (within 15 days) and mechanical ventilation duration before VAP onset. Fifty-six (33%) patients had at least one VAP recurrence, and 56 (33%) died. Factors independently associated with an unfavorable outcome (recurrence or death) were a high day 7 sequential organ failure assessment score and mechanical ventilation dependency on day 7. Physicians freely prescribed a carbapenem to 88 patients: imipenem for 32, meropenem for 24, and doripenem for 32. The remaining 81 patients were treated with various antibiotics. Imipenem-, meropenem-, and doripenem-treated patients had similar VAP recurrence rates (41%, 25%, and 22%, respectively; P=0.15) and mortality rates (47%, 25%, and 22%, respectively; P=0.07). Carbapenem resistance emerged similarly among patients treated with any carbapenem. No carbapenem was superior to another for preventing carbapenem resistance emergence.

Analysis of Pseudomonas aeruginosa diguanylate cyclases and phosphodiesterases reveals a role for bis-(3′-5′)-cyclic-GMP in virulence

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Kulesekara, Hemantha; Lee, Vincent; Brencic, Anja; Liberati, Nicole; Urbach, Jonathan; Miyata, Sachiko; Lee, Daniel G.; Neely, Alice N.; Hyodo, Mamoru; Hayakawa, Yoshihiro; Ausubel, Frederick M.; Lory, Stephen

2006-01-01

The opportunistic pathogen Pseudomonas aeruginosa is responsible for systemic infections in immunocompromised individuals and chronic respiratory disease in patients with cystic fibrosis. Cyclic nucleotides are known to play a variety of roles in the regulation of virulence-related factors in pathogenic bacteria. A set of P. aeruginosa genes, encoding proteins that contain putative domains characteristic of diguanylate cyclases (DGCs) and phosphodiesterases (PDEs) that are responsible for the maintenance of cellular levels of the second messenger bis-(3′-5′)-cyclic dimeric GMP (c-di-GMP) was identified in the annotated genomes of P. aeruginosa strains PAO1 and PA14. Although the majority of these genes are components of the P. aeruginosa core genome, several are located on presumptive horizontally acquired genomic islands. A comprehensive analysis of P. aeruginosa genes encoding the enzymes of c-di-GMP metabolism (DGC- and PDE-encoding genes) was carried out to analyze the function of c-di-GMP in two disease-related phenomena, cytotoxicity and biofilm formation. Analysis of the phenotypes of DGC and PDE mutants and overexpressing clones revealed that certain virulence-associated traits are controlled by multiple DGCs and PDEs through alterations in c-di-GMP levels. A set of mutants in selected DGC- and PDE-encoding genes exhibited attenuated virulence in a mouse infection model. Given that insertions in different DGC and PDE genes result in distinct phenotypes, it seems likely that the formation or degradation of c-di-GMP by these enzymes is in highly localized and intimately linked to particular targets of c-di-GMP action. PMID:16477007

FpvA receptor involvement in pyoverdine biosynthesis in Pseudomonas aeruginosa.

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Shen, Jiangsheng; Meldrum, Allison; Poole, Keith

2002-06-01

Alignment of the Pseudomonas aeruginosa ferric pyoverdine receptor, FpvA, with similar ferric-siderophore receptors revealed that the mature protein carries an extension of ca. 70 amino acids at its N terminus, an extension shared by the ferric pseudobactin receptors of P. putida. Deletion of fpvA from the chromosome of P. aeruginosa reduced pyoverdine production in this organism, as a result of a decline in expression of genes (e.g., pvdD) associated with the biosynthesis of the pyoverdine peptide moiety. Wild-type fpvA restored pvd expression in the mutant, thereby complementing its pyoverdine deficiency, although a deletion derivative of fpvA encoding a receptor lacking the N terminus of the mature protein did not. The truncated receptor was, however, functional in pyoverdine-mediated iron uptake, as evidenced by its ability to promote pyoverdine-dependent growth in an iron-restricted medium. These data are consistent with the idea that the N-terminal extension plays a role in FpvA-mediated pyoverdine biosynthesis in P. aeruginosa.

Selective imipenem resistance in Pseudomonas aeruginosa associated with diminished outer membrane permeability.

OpenAIRE

Studemeister, A E; Quinn, J P

1988-01-01

The permeability of the outer membranes of imipenem-susceptible and imipenem-resistant clinical isolates of Pseudomonas aeruginosa was investigated by the liposome swelling assay. Sugars and cephaloridine penetrated rapidly, whereas imipenem penetrated poorly into liposomes constructed from porin-rich outer membrane fractions of the resistant isolates.

CHARACTERIZATION OF PB2+ UPTAKE AND SEQUESTRATION IN PSEUDOMONAS AERUGINOSA CHL004

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

The Effects of Chinese Herbal Medicines on the Quorum Sensing-Regulated Virulence in Pseudomonas aeruginosa PAO1

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Yee Meng Chong

2018-04-01

Full Text Available The quorum sensing (QS system has been used by many opportunistic pathogenic bacteria to coordinate their virulence determinants in relation to cell-population density. As antibiotic-resistant bacteria are on the rise, interference with QS has been regarded as a novel way to control bacterial infections. As such, many plant-based natural products have been widely explored for their therapeutic roles. These natural products may contain anti-QS compounds that could block QS signals generation or transmission to combat QS pathogens. In this study, we report the anti-QS activities of four different Chinese herbal plant extracts: Poria cum Radix pini, Angelica dahurica, Rhizoma cibotii and Schizonepeta tenuifolia, on Pseudomonas aeruginosa PAO1. All the plants extracted using hexane, chloroform and methanol were tested and found to impair swarming motility and pyocyanin production in P. aeruginosa PAO1, particularly by Poria cum Radix pini. In addition, all the plant extracts also inhibited violacein production in C. violaceum CV026 up to 50% while bioluminescence activities were reduced in lux-based E. coli biosensors, pSB401 and pSB1075, up to about 57%. These anti-QS properties of the four medicinal plants are the first documentation that demonstrates a potential approach to attenuate pathogens’ virulence determinants.

Why Does the Healthy Cornea Resist Pseudomonas aeruginosa Infection?

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

2013-01-01

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

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

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

2007-01-01

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

Epidemiology of Pseudomonas aeruginosa in cystic fibrosis and the possible role of contamination by dental equipment

DEFF Research Database (Denmark)

Jensen, E T; Giwercman, B; Ojeniyi, B

1997-01-01

Cystic fibrosis (CF) patients often suffer from Pseudomonas aeruginosa lung infection yet the source of this organism is not known. In order to determine whether CF patients might be contaminated with P. aeruginosa from dental equipment, a total of 103 water samples from 25 dental sessions...... samples (5.5%) from nine sessions (11%) were positive for P. aeruginosa. In one case, genotypically identical (RFLP, pulsed-field gel electrophoresis) P. aeruginosa strains were found both in water from the dental equipment and in the CF patients sputum. This indicates a small risk for acquiring P...

Effect of methylglyoxal on multidrug-resistant Pseudomonas aeruginosa

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Katsuhiko eHayashi

2014-04-01

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

Identification of biofilm-associated cluster (bac in Pseudomonas aeruginosa involved in biofilm formation and virulence.

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Camille Macé

Full Text Available Biofilms are prevalent in diseases caused by Pseudomonas aeruginosa, an opportunistic and nosocomial pathogen. By a proteomic approach, we previously identified a hypothetical protein of P. aeruginosa (coded by the gene pA3731 that was accumulated by biofilm cells. We report here that a Delta pA3731 mutant is highly biofilm-defective as compared with the wild-type strain. Using a mouse model of lung infection, we show that the mutation also induces a defect in bacterial growth during the acute phase of infection and an attenuation of the virulence. The pA3731 gene is found to control positively the ability to swarm and to produce extracellular rhamnolipids, and belongs to a cluster of 4 genes (pA3729-pA3732 not previously described in P. aeruginosa. Though the protein PA3731 has a predicted secondary structure similar to that of the Phage Shock Protein, some obvious differences are observed compared to already described psp systems, e.g., this unknown cluster is monocistronic and no homology is found between the other proteins constituting this locus and psp proteins. As E. coli PspA, the amount of the protein PA3731 is enlarged by an osmotic shock, however, not affected by a heat shock. We consequently named this locus bac for biofilm-associated cluster.

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

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Habibi, Asghar; Honarmand, Ramin

2015-12-01

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. 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. 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. 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. 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.

In silico and In vitro activity of ceftolozane/tazobactam against pseudomonas aeruginosa collected across Indian hospitals

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Agila Kumari Pragsam

2018-01-01

Full Text Available Ceftolozane/tazobactam is a novel antimicrobial agent with activity against Pseudomonas aeruginosa and other common Gram-negative pathogens. In this study, we determined the antimicrobial susceptibility for a total of 149 clinical isolates of P. aeruginosa for the most commonly used antimicrobials including the new agent ceftolozane/tazobactam (C/T. Broth microdilution was performed to determine the minimum inhibitory concentration against various antimicrobials including C/T. Among the β-lactam/β-lactamase inhibitor, overall susceptibility was 67%, 55% and 51% for C/T, Piperacillin/Tazobactam (P/T and Cefoperazone/Sulbactam, respectively. The variations in the susceptibility rates were noted among the three different β-lactam/β-lactamase inhibitors. Interestingly, 33% susceptibility was noted for C/T against isolates that were resistant to P/T, indicating the higher activity of C/T. This finding suggests about 33% of the P/T-resistant isolates can still be treated effectively with C/T. C/T could be a better alternative for the treatment of ESBL-producing organism, and thereby usage of higher antimicrobials can be minimised.

Comparative genome and transcriptome analysis reveals distinctive surface characteristics and unique physiological potentials of Pseudomonas aeruginosa ATCC 27853

KAUST Repository

Cao, Huiluo; Lai, Yong; Bougouffa, Salim; Xu, Zeling; Yan, Aixin

2017-01-01

Pseudomonas aeruginosa ATCC 27853 was isolated from a hospital blood specimen in 1971 and has been widely used as a model strain to survey antibiotics susceptibilities, biofilm development, and metabolic activities of Pseudomonas spp.. Although four

Pseudomonas Exotoxin A: optimized by evolution for effective killing

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Marta eMichalska

2015-09-01

Full Text Available Pseudomonas Exotoxin A (PE is the most toxic virulence factor of the pathogenic bacterium Pseudomonas aeruginosa. This review describes current knowledge about the intoxication pathways of PE. Moreover, PE represents a remarkable example for pathoadaptive evolution, how bacterial molecules have been structurally and functionally optimized under evolutionary pressure to effectively impair and kill their host cells.

Outbreak of infection in a burns unit due to Pseudomonas aeruginosa originating from contaminated tubing used for irrigation of patients

DEFF Research Database (Denmark)

Kolmos, H J; Thuesen, B; Nielsen, S V

1993-01-01

water used for irrigation of the burns, as part of the first-aid treatment which the patients received when entering the hospital. Contamination was restricted to showers and tubing that were permanently connected to the taps, and the outbreak stopped after they had been disinfected. Tubing and showers...... used for irrigation of burns should be dismantled and heat-disinfected after each patient and not reconnected to the taps until immediately before the next treatment. Taps used for irrigation of burns should be monitored regularly for the presence of P. aeruginosa and other potentially pathogenic......Five patients with extensive deep burns developed septicaemia due to Pseudomonas aeruginosa serogroup O-7.8 and phage type 21 or 21/188 shortly after they had been admitted to hospital. Four other burned patients became colonized with the same strain. The source of infection was contaminated tap...

Acidosis increases the susceptibility of respiratory epithelial cells to Pseudomonas aeruginosa-induced cytotoxicity.

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Torres, Iviana M; Demirdjian, Sally; Vargas, Jennifer; Goodale, Britton C; Berwin, Brent

2017-07-01

Bacterial infection can lead to acidosis of the local microenvironment, which is believed to exacerbate disease pathogenesis; however, the mechanisms by which changes in pH alter disease progression are poorly understood. We test the hypothesis that acidosis enhances respiratory epithelial cell death in response to infection with Pseudomonas aeruginosa Our findings support the idea that acidosis in the context of P. aeruginosa infection results in increased epithelial cell cytotoxicity due to ExoU intoxication. Importantly, enforced maintenance of neutral pH during P. aeruginosa infection demonstrates that cytotoxicity is dependent on the acidosis. Investigation of the underlying mechanisms revealed that host cell cytotoxicity correlated with increased bacterial survival during an acidic infection that was due to reduced bactericidal activity of host-derived antimicrobial peptides. These findings extend previous reports that the activities of antimicrobial peptides are pH-dependent and provide novel insights into the consequences of acidosis on infection-derived pathology. Therefore, this report provides the first evidence that physiological levels of acidosis increase the susceptibility of epithelial cells to acute Pseudomonas infection and demonstrates the benefit of maintaining pH homeostasis during a bacterial infection. Copyright © 2017 the American Physiological Society.

Identification of Fitness Determinants during Energy-Limited Growth Arrest in Pseudomonas aeruginosa.

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Basta, David W; Bergkessel, Megan; Newman, Dianne K

2017-11-28

infections. Identification of the genes required for survival of growth arrest (encompassing entry, maintenance, and exit) is an important first step toward understanding the physiology of bacteria in this state. Using Tn-seq, we identified and validated genes required for fitness of Pseudomonas aeruginosa when energy limited for organic carbon or oxygen, which represent two common causes of growth arrest for P. aeruginosa in diverse habitats. This unbiased, genome-wide survey is the first to reveal essential activities for a pathogen experiencing different types of energy limitation, finding both shared and divergent activities that are relevant at different survival stages. Future efforts can now be directed toward understanding how the biomolecules responsible for these activities contribute to fitness under these conditions. Copyright © 2017 Basta et al.

Draft Genome Sequence of an Invasive Multidrug-Resistant Strain, Pseudomonas aeruginosa BK1, Isolated from a Keratitis Patient

KAUST Repository

Jeganathan, Lakshmi Priya; Prakash, Logambiga; Neelamegam, Sivakumar; Antony, Aju; Alqarawi, Sami; Prajna, Lalitha; Devarajan, Bharanidharan; Mohankumar, Vidyarani

2014-01-01

Pseudomonas aeruginosa infections are difficult to treat due to the presence of a multitude of virulence factors and antibiotic resistance. Here, we report the draft genome sequence of P. aeruginosa BK1, an invasive and multidrug-resistant strain

A Microfluidic Channel Method for Rapid Drug-Susceptibility Testing of Pseudomonas aeruginosa.

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Yoshimi Matsumoto

Full Text Available The recent global increase in the prevalence of antibiotic-resistant bacteria and lack of development of new therapeutic agents emphasize the importance of selecting appropriate antimicrobials for the treatment of infections. However, to date, the development of completely accelerated drug susceptibility testing methods has not been achieved despite the availability of a rapid identification method. We proposed an innovative rapid method for drug susceptibility testing for Pseudomonas aeruginosa that provides results within 3 h. The drug susceptibility testing microfluidic (DSTM device was prepared using soft lithography. It consisted of five sets of four microfluidic channels sharing one inlet slot, and the four channels are gathered in a small area, permitting simultaneous microscopic observation. Antimicrobials were pre-introduced into each channel and dried before use. Bacterial suspensions in cation-adjusted Mueller-Hinton broth were introduced from the inlet slot and incubated for 3 h. Susceptibilities were microscopically evaluated on the basis of differences in cell numbers and shapes between drug-treated and control cells, using dedicated software. The results of 101 clinically isolated strains of P. aeruginosa obtained using the DSTM method strongly correlated with results obtained using the ordinary microbroth dilution method. Ciprofloxacin, meropenem, ceftazidime, and piperacillin caused elongation in susceptible cells, while meropenem also induced spheroplast and bulge formation. Morphological observation could alternatively be used to determine the susceptibility of P. aeruginosa to these drugs, although amikacin had little effect on cell shape. The rapid determination of bacterial drug susceptibility using the DSTM method could also be applicable to other pathogenic species, and it could easily be introduced into clinical laboratories without the need for expensive instrumentation.

Comparison of double-locus sequence typing (DLST) and multilocus sequence typing (MLST) for the investigation of Pseudomonas aeruginosa populations.

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Cholley, Pascal; Stojanov, Milos; Hocquet, Didier; Thouverez, Michelle; Bertrand, Xavier; Blanc, Dominique S

2015-08-01

Reliable molecular typing methods are necessary to investigate the epidemiology of bacterial pathogens. Reference methods such as multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) are costly and time consuming. Here, we compared our newly developed double-locus sequence typing (DLST) method for Pseudomonas aeruginosa to MLST and PFGE on a collection of 281 isolates. DLST was as discriminatory as MLST and was able to recognize "high-risk" epidemic clones. Both methods were highly congruent. Not surprisingly, a higher discriminatory power was observed with PFGE. In conclusion, being a simple method (single-strand sequencing of only 2 loci), DLST is valuable as a first-line typing tool for epidemiological investigations of P. aeruginosa. Coupled to a more discriminant method like PFGE or whole genome sequencing, it might represent an efficient typing strategy to investigate or prevent outbreaks. Copyright © 2015 Elsevier Inc. All rights reserved.

Rapid detection of Pseudomonas aeruginosa from positive blood cultures by quantitative PCR

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Cattoir Vincent

2010-08-01

Full Text Available Abstract Background Pseudomonas aeruginosa is responsible for numerous bloodstream infections associated with severe adverse outcomes in case of inappropriate initial antimicrobial therapy. The present study was aimed to develop a novel quantitative PCR (qPCR assay, using ecfX as the specific target gene, for the rapid and accurate identification of P. aeruginosa from positive blood cultures (BCs. Methods Over the period August 2008 to June 2009, 100 BC bottles positive for gram-negative bacilli were tested in order to evaluate performances of the qPCR technique with conventional methods as gold standard (i.e. culture and phenotypic identification. Results Thirty-three strains of P. aeruginosa, 53 strains of Enterobactericaeae, nine strains of Stenotrophomonas maltophilia and two other gram-negative species were isolated while 3 BCs were polymicrobial including one mixture containing P. aeruginosa. All P. aeruginosa clinical isolates were detected by qPCR except a single strain in mixed culture. Performances of the qPCR technique were: specificity, 100%; positive predictive value, 100%; negative predictive value, 98.5%; and sensitivity, 97%. Conclusions This reliable technique may offer a rapid (

Molecular analysis of volatile metabolites released specifically by staphylococcus aureus and pseudomonas aeruginosa

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Filipiak Wojciech

2012-06-01

Full Text Available Abstract Background The routinely used microbiological diagnosis of ventilator associated pneumonia (VAP is time consuming and often requires invasive methods for collection of human specimens (e.g. bronchoscopy. Therefore, it is of utmost interest to develop a non-invasive method for the early detection of bacterial infection in ventilated patients, preferably allowing the identification of the specific pathogens. The present work is an attempt to identify pathogen-derived volatile biomarkers in breath that can be used for early and non- invasive diagnosis of ventilator associated pneumonia (VAP. For this purpose, in vitro experiments with bacteria most frequently found in VAP patients, i.e. Staphylococcus aureus and Pseudomonas aeruginosa, were performed to investigate the release or consumption of volatile organic compounds (VOCs. Results Headspace samples were collected and preconcentrated on multibed sorption tubes at different time points and subsequently analyzed with gas chromatography mass spectrometry (GC-MS. As many as 32 and 37 volatile metabolites were released by S. aureus and P. aeruginosa, respectively. Distinct differences in the bacteria-specific VOC profiles were found, especially with regard to aldehydes (e.g. acetaldehyde, 3-methylbutanal, which were taken up only by P. aeruginosa but released by S. aureus. Differences in concentration profiles were also found for acids (e.g. isovaleric acid, ketones (e.g. acetoin, 2-nonanone, hydrocarbons (e.g. 2-butene, 1,10-undecadiene, alcohols (e.g. 2-methyl-1-propanol, 2-butanol, esters (e.g. ethyl formate, methyl 2-methylbutyrate, volatile sulfur compounds (VSCs, e.g. dimethylsulfide and volatile nitrogen compounds (VNCs, e.g. 3-methylpyrrole. Importantly, a significant VOC release was found already 1.5 hours after culture start, corresponding to cell numbers of ~8*106 [CFUs/ml]. Conclusions The results obtained provide strong evidence that the detection and perhaps even

The effect of loss of O-antigen ligase on phagocytic susceptibility of motile and non-motile Pseudomonas aeruginosa.

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Demirdjian, Sally; Schutz, Kristin; Wargo, Matthew J; Lam, Joseph S; Berwin, Brent

2017-12-01

The bacterial pathogen Pseudomonas aeruginosa undergoes adaptation and selection over the course of chronic respiratory tract infections which results in repeatedly-observed phenotypic changes that are proposed to enable its persistence. Two of the clinically significant P. aeruginosa phenotypic changes are loss of flagellar motility and modifications to LPS structure, including loss of O-antigen expression. The effect of loss of O-antigen, frequently described as conversion from smooth to rough LPS, and the combined effect of loss of motility and O-antigen on phagocytic susceptibility by immune cells remain unknown. To address this, we generated genetic deletion mutants of waaL, which encodes the O-antigen ligase responsible for linking O-antigen to lipid A-core oligosaccharide, in both motile and non-motile P. aeruginosa strains. With the use of these bacterial strains we provide the first demonstration that, despite a progressive selection for P. aeruginosa with rough LPS during chronic pulmonary infections, loss of the LPS O-antigen does not confer phagocytic resistance in vitro. However, use of the waaLmotABmotCD mutant revealed that loss of motility confers resistance to phagocytosis regardless of the smooth or rough LPS phenotype. These findings reveal how the O-antigen of P. aeruginosa can influence bacterial clearance during infection and expand our current knowledge about the impact of bacterial phenotypic changes during chronic infection. Copyright © 2017 Elsevier Ltd. All rights reserved.

Precision-engineering the Pseudomonas aeruginosa genome with two-step allelic exchange

DEFF Research Database (Denmark)

Hmelo, Laura R; Borlee, Bradley R; Almblad, Henrik

2015-01-01

Allelic exchange is an efficient method of bacterial genome engineering. This protocol describes the use of this technique to make gene knockouts and knock-ins, as well as single-nucleotide insertions, deletions and substitutions, in Pseudomonas aeruginosa. Unlike other approaches to allelic exch...

Expression of Pseudomonas aeruginosa transposable phages in Pseudomonas putida cells. I. Establishment of lysogeny and lytic growth efficiency

Energy Technology Data Exchange (ETDEWEB)

Gorbunova, S.A.; Yanenko, A.S.; Akhverdyan, V.Z.; Reulets, M.A.; Krylov, V.N.

1986-03-01

Expression of the genomes of Pseudomonas aeruginosa transposable phages (TP) in the cells of a heterologous host, P. putida PpGl, was studied. A high efficiency of TP lytic growth in PpGl cells was obtained both after zygotic induction following RP4::TP plasmid transfer and after thermoinduction of PpGl cells lysogenic for thermoinducible prophage D3112cts15. Characteristic for PpGl cells was a high TP yield (20-25 phage D3112cts15 particles per cell), which was evidence of a high level of TP transposition in cells of this species. The frequency of RP4::TP transfer into PpGl and PA01 cells was equal, but the lysogeny detection rat was somewhat lower in PpGl. Pseudomonas aeruginosa TP can integrate into the PpGl chromosome, producing inducible lysogens. The presence of RP4 is not necessary for the expression of the TP genome in PpGl cells. The D3112cts15 TP may be used for interspecific transduction of plasmids and chromosomal markers.

Expression of Pseudomonas aeruginosa transposable phages in Pseudomonas putida cells. I. Establishment of lysogeny and lytic growth efficiency

International Nuclear Information System (INIS)

Gorbunova, S.A.; Yanenko, A.S.; Akhverdyan, V.Z.; Reulets, M.A.; Krylov, V.N.

1986-01-01

Expression of the genomes of Pseudomonas aeruginosa transposable phages (TP) in the cells of a heterologous host, P. putida PpGl, was studied. A high efficiency of TP lytic growth in PpGl cells was obtained both after zygotic induction following RP4::TP plasmid transfer and after thermoinduction of PpGl cells lysogenic for thermoinducible prophage D3112cts15. Characteristic for PpGl cells was a high TP yield (20-25 phage D3112cts15 particles per cell), which was evidence of a high level of TP transposition in cells of this species. The frequency of RP4::TP transfer into PpGl and PA01 cells was equal, but the lysogeny detection rat was somewhat lower in PpGl. Pseudomonas aeruginosa TP can integrate into the PpGl chromosome, producing inducible lysogens. The presence of RP4 is not necessary for the expression of the TP genome in PpGl cells. The D3112cts15 TP may be used for interspecific transduction of plasmids and chromosomal markers

Diversity, Prevalence, and Longitudinal Occurrence of Type II Toxin-Antitoxin Systems of Pseudomonas aeruginosa Infecting Cystic Fibrosis Lungs

DEFF Research Database (Denmark)

Breum Andersen, Sandra; Ghoul, Melanie; Griffin, Ashleigh S.

2017-01-01

Type II toxin-antitoxin (TA) systems are most commonly composed of two genes encoding a stable toxin, which harms the cell, and an unstable antitoxin that can inactivate it. TA systems were initially characterized as selfish elements, but have recently gained attention for regulating general stress...... responses responsible for pathogen virulence, formation of drug-tolerant persister cells and biofilms—all implicated in causing recalcitrant chronic infections. We use a bioinformatics approach to explore the distribution and evolution of type II TA loci of the opportunistic pathogen, Pseudomonas aeruginosa...... in their core genome and a variable number of the remaining 22 on genomic islands; (2) limited mutations in core genome TA loci, suggesting they are not under negative selection; (3) no evidence for horizontal transmission of elements with TA systems between clone types within patients, despite their ability...

Long-distance delivery of bacterial virulence factors by Pseudomonas aeruginosa outer membrane vesicles.

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Jennifer M Bomberger

2009-04-01

Full Text Available Bacteria use a variety of secreted virulence factors to manipulate host cells, thereby causing significant morbidity and mortality. We report a mechanism for the long-distance delivery of multiple bacterial virulence factors, simultaneously and directly into the host cell cytoplasm, thus obviating the need for direct interaction of the pathogen with the host cell to cause cytotoxicity. We show that outer membrane-derived vesicles (OMV secreted by the opportunistic human pathogen Pseudomonas aeruginosa deliver multiple virulence factors, including beta-lactamase, alkaline phosphatase, hemolytic phospholipase C, and Cif, directly into the host cytoplasm via fusion of OMV with lipid rafts in the host plasma membrane. These virulence factors enter the cytoplasm of the host cell via N-WASP-mediated actin trafficking, where they rapidly distribute to specific subcellular locations to affect host cell biology. We propose that secreted virulence factors are not released individually as naked proteins into the surrounding milieu where they may randomly contact the surface of the host cell, but instead bacterial derived OMV deliver multiple virulence factors simultaneously and directly into the host cell cytoplasm in a coordinated manner.

Hemorrhagic pneumonia in mink caused by Pseudomonas aeruginosa

DEFF Research Database (Denmark)

Salomonsen, Charlotte Mark

research has been performed in this field and most published work is more than 25 years old. The studies presented in this thesis aim at elucidating varying aspects of the disease: Article I investigates the relationships of P. aeruginosa isolated from mink hemorrhagic pneumonia using pulsed field gel...... electrophoresis (PFGE) and a commercial typing system based on single nucleotide polymorphisms (SNP) on chosen strains. The results presented in this article show that 70% of P. aeruginosa isolated from outbreaks of hemorrhagic pneumonia in mink consist of unique strains, while the remaining 30% belongs to either...... in hemorrhagic pneumonia caused by P. aeruginosa and E. coli in diagnostic material. The distribution of the two pathogens is visualized using fluorescence in situ hybridization (FISH). Two histological patterns were observed in the work presented in Article II; one was very hemorrhagic with few bacteria while...

Assessment of serology and spirometry and the combination of both to complement microbiological isolation for earlier detection of Pseudomonas aeruginosa infection in children with cystic fibrosis.

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Kotnik Pirš, Ana; Krivec, Uroš; Simčič, Saša; Seme, Katja

2016-11-25

The aim of this study was to assess whether serology and spirometry and the combination of both can complement culture-based detection for earlier recognition of Pseudomonas aeruginosa infection in children with cystic fibrosis. A 4 year longitudinal prospective study that included 67 Slovenian children with cystic fibrosis with a mean age of 10.5 years was conducted. Serology, spirometry and a scoring system combining serology and spirometry were assessed and compared. Infection was confirmed with isolation of Pseudomonas aeruginosa from respiratory samples. There was a significantly positive correlation between serology and the combination of serology and spirometry and Pseudomonas aeruginosa isolation (P spirometry and Pseudomonas aeruginosa isolation (P spirometry the highest sensitivity (0.90). Both had a high negative predictive value (0.93 and 0.79 respectively). Using serology and the combination of serology and lung function measurement can be beneficial for earlier detection of infection with Pseudomonas aeruginosa in children with cystic fibrosis when done simultaneously with standard culture-based detection from respiratory samples.

Boolean network model of the Pseudomonas aeruginosa quorum sensing circuits.

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Dallidis, Stylianos E; Karafyllidis, Ioannis G

2014-09-01

To coordinate their behavior and virulence and to synchronize attacks against their hosts, bacteria communicate by continuously producing signaling molecules (called autoinducers) and continuously monitoring the concentration of these molecules. This communication is controlled by biological circuits called quorum sensing (QS) circuits. Recently QS circuits and have been recognized as an alternative target for controlling bacterial virulence and infections without the use of antibiotics. Pseudomonas aeruginosa is a Gram-negative bacterium that infects insects, plants, animals and humans and can cause acute infections. This bacterium has three interconnected QS circuits that form a very complex and versatile QS system, the operation of which is still under investigation. Here we use Boolean networks to model the complete QS system of Pseudomonas aeruginosa and we simulate and analyze its operation in both synchronous and asynchronous modes. The state space of the QS system is constructed and it turned out to be very large, hierarchical, modular and scale-free. Furthermore, we developed a simulation tool that can simulate gene knock-outs and study their effect on the regulons controlled by the three QS circuits. The model and tools we developed will give to life scientists a deeper insight to this complex QS system.

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

International Nuclear Information System (INIS)

Gohain, Neelakshi; Thomashow, Linda S.; Mavrodi, Dmitri V.; Blankenfeldt, Wulf

2006-01-01

PhzM, an S-adenosylmethionine-dependent methyltransferase enzyme that catalyzes a reaction involved in the biosynthesis of pyocyanin in P. aeruginosa, was cloned, overexpressed and crystallized. Data collection from native and selenomethionine-labelled crystals is reported. Pyocyanin, phenazine-1-carboxylic acid and more than 70 related compounds collectively known as phenazines are produced by various species of Pseudomonas, including the fluorescent pseudomonad P. aeruginosa, a Gram-negative opportunistic pathogen in humans and animals. P. aeruginosa synthesizes a characteristic blue water-soluble compound called pyocyanin (1-hydroxy-5-methyl-phenazine). Two enzymes designated PhzM and PhzS are involved in the terminal steps of its synthesis and very little is known about these enzymes. In this study, PhzM, a dimeric S-adenosylmethionine-dependent methyltransferase, was purified and crystallized from PEG 3350/sodium cacodylate/sodium citrate pH 6.5. The crystals belong to space group P1, with unit-cell parameters a = 46.1, b = 61.8, c = 69.6 Å, α = 96.3, β = 106.6, γ = 106.9°. They contain one dimer in the asymmetric unit and diffract to a resolution of 1.8 Å. Anomalous data to 2.3 Å resolution have been collected from seleno-l-methionine-labelled PhzM

Genomics of antibiotic-resistance prediction in Pseudomonas aeruginosa.

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Jeukens, Julie; Freschi, Luca; Kukavica-Ibrulj, Irena; Emond-Rheault, Jean-Guillaume; Tucker, Nicholas P; Levesque, Roger C

2017-06-02

Antibiotic resistance is a worldwide health issue spreading quickly among human and animal pathogens, as well as environmental bacteria. Misuse of antibiotics has an impact on the selection of resistant bacteria, thus contributing to an increase in the occurrence of resistant genotypes that emerge via spontaneous mutation or are acquired by horizontal gene transfer. There is a specific and urgent need not only to detect antimicrobial resistance but also to predict antibiotic resistance in silico. We now have the capability to sequence hundreds of bacterial genomes per week, including assembly and annotation. Novel and forthcoming bioinformatics tools can predict the resistome and the mobilome with a level of sophistication not previously possible. Coupled with bacterial strain collections and databases containing strain metadata, prediction of antibiotic resistance and the potential for virulence are moving rapidly toward a novel approach in molecular epidemiology. Here, we present a model system in antibiotic-resistance prediction, along with its promises and limitations. As it is commonly multidrug resistant, Pseudomonas aeruginosa causes infections that are often difficult to eradicate. We review novel approaches for genotype prediction of antibiotic resistance. We discuss the generation of microbial sequence data for real-time patient management and the prediction of antimicrobial resistance. © 2017 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals Inc. on behalf of The New York Academy of Sciences.

An Antipersister Strategy for Treatment of Chronic Pseudomonas aeruginosa Infections.

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Koeva, Martina; Gutu, Alina D; Hebert, Wesley; Wager, Jeffrey D; Yonker, Lael M; O'Toole, George A; Ausubel, Frederick M; Moskowitz, Samuel M; Joseph-McCarthy, Diane

2017-12-01

Bacterial persisters are a quasidormant subpopulation of cells that are tolerant to antibiotic treatment. The combination of the aminoglycoside tobramycin with fumarate as an antibacterial potentiator utilizes an antipersister strategy that is aimed at reducing recurrent Pseudomonas aeruginosa infections by enhancing the killing of P. aeruginosa persisters. Stationary-phase cultures of P. aeruginosa were used to generate persister cells. A range of tobramycin concentrations was tested with a range of metabolite concentrations to determine the potentiation effect of the metabolite under a variety of conditions, including a range of pH values and in the presence of azithromycin or cystic fibrosis (CF) patient sputum. In addition, 96-well dish biofilm and colony biofilm assays were performed, and the cytotoxicity of the tobramycin-fumarate combination was determined utilizing a lactate dehydrogenase (LDH) assay. Enhanced killing of up to 6 orders of magnitude of P. aeruginosa persisters over a range of CF isolates, including mucoid and nonmucoid strains, was observed for the tobramycin-fumarate combination compared to killing with tobramycin alone. Furthermore, significant fumarate-mediated potentiation was seen in the presence of azithromycin or CF patient sputum. Fumarate also reduced the cytotoxicity of tobramycin-treated P. aeruginosa to human epithelial airway cells. Finally, in mucoid and nonmucoid CF isolates, complete eradication of P. aeruginosa biofilm was observed in the colony biofilm assay due to fumarate potentiation. These data suggest that a combination of tobramycin with fumarate as an antibacterial potentiator may be an attractive therapeutic for eliminating recurrent P. aeruginosa infections in CF patients through the eradication of bacterial persisters. Copyright © 2017 American Society for Microbiology.

Glycolipid-Dependent, Protease Sensitive Internalization of Pseudomonas aeruginosa Into Cultured Human Respiratory Epithelial Cells

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Emam, Aufaugh; Carter, William G; Lingwood, Clifford

2010-01-01

Internalization of PAK strain Pseudomonas aeruginosa into human respiratory epithelial cell lines and HeLa cervical cancer cells in vitro was readily demonstrable via a gentamycin protection assay. Depletion of target cell glycosphingolipids (GSLs) using a glucosyl ceramide synthase inhibitor, P4, completely prevented P. aeruginosa internalization. In contrast, P4 treatment had no effect on the internalization of Salmonella typhimurium into HeLa cells. Internalized P. aeruginosa were within membrane vacuoles, often containing microvesicles, between the bacterium and the limiting membrane. P. aeruginosa internalization was markedly enhanced by target cell pretreatment with the exogenous GSL, deacetyl gangliotetraosyl ceramide (Gg4). Gg4 binds the lipid raft marker, GM1 ganglioside. Target cell pretreatment with TLCK, but not other (serine) protease inhibitors, prevented both P. aeruginosa host cell binding and internalization. NFkB inhibition also prevented internalization. A GSL-containing lipid-raft model of P. aeruginosa host cell binding/internalization is proposed PMID:21270937

Carbapenem Susceptibility and Multidrug-Resistance in Pseudomonas aeruginosa Isolates in Egypt.

Science.gov (United States)

Hashem, Hany; Hanora, Amro; Abdalla, Salah; Shawky, Alaa; Saad, Alaa

2016-11-01

Resistant Pseudomonas aeruginosa is a serious concern for antimicrobial therapy, as the common isolates exhibit variable grades of resistance, involving beta-lactamase enzymes, beside native defense mechanisms. The present study was designed to determine the occurrence of Metallo-β- Lactamases (MBL) and Amp C harboring P. aeruginosa isolates from Suez Canal university hospital in Ismailia, Egypt. A total of 147 P. aeruginosa isolates, recovered from 311 patients during a 10-month period, were collected between May 2013 and February 2014; the isolates were collected from urine, wound and sputum. Minimum inhibitory concentration (MIC) determined by agar dilution methods was ≥2 μg/mL for meropenem and imipenem. Identification of P. aeruginosa was confirmed using API 20NE. Metallo-β- Lactamases and Amp C were detected based on different phenotypic methods. Overall, 26.5% of P. aeruginosa isolates (39/147) were carbapenem resistant isolates. Furthermore, 64.1% (25/39) were MBL producers, these isolates were screened by the combined disc and disc diffusion methods to determine the ability of MBL production. Both MBL and Amp C harbored P. aeruginosa isolates were 28% (7/25). Sixty-four percent of P. aeruginosa isolates were multidrug resistant (MDR) (16/25). The sensitivity toward polymyxin, imipenem, norfloxacin, piperacillin-tazobactam and gentamicin was 99%, 91%, 88%, 82% and 78%, respectively. The resistance rate towards cefotaxime, ceftazidime, cefepime, aztreonam and meropenem was 98.6%, 86%, 71.4%, 34% and 30%, respectively. Multidrug resistance was significantly associated with MBL production in P. aeruginosa . Early detection of MBL-producing P. aeruginosa and hospital antibiotic policy prescription helps proper antimicrobial therapy and avoidance of dissemination of these multidrug resistance isolates.

Polymorphonuclear leucocytes consume oxygen in sputum from chronic Pseudomonas aeruginosa pneumonia in cystic fibrosis

DEFF Research Database (Denmark)

Kolpen, Mette; Hansen, C. R.; Bjarnsholt, Thomas

2010-01-01

BACKGROUND: Chronic lung infection with Pseudomonas aeruginosa is the most severe complication for patients with cystic fibrosis (CF). This infection is characterised by endobronchial mucoid biofilms surrounded by numerous polymorphonuclear leucocytes (PMNs). The mucoid phenotype offers protection...

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

Directory of Open Access Journals (Sweden)

Saravanan ePeriasamy

2015-08-01

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

Pseudomonas aeruginosa keratitis: outcomes and response to corticosteroid treatment.

Science.gov (United States)

Sy, Aileen; Srinivasan, Muthiah; Mascarenhas, Jeena; Lalitha, Prajna; Rajaraman, Revathi; Ravindran, Meenakshi; Oldenburg, Catherine E; Ray, Kathryn J; Glidden, David; Zegans, Michael E; McLeod, Stephen D; Lietman, Thomas M; Acharya, Nisha R

2012-01-25

To compare the clinical course and effect of adjunctive corticosteroid therapy in Pseudomonas aeruginosa with those of all other strains of bacterial keratitis. Subanalyses were performed on data collected in the Steroids for Corneal Ulcers Trial (SCUT), a large randomized controlled trial in which patients were treated with moxifloxacin and were randomly assigned to 1 of 2 adjunctive treatment arms: corticosteroid or placebo (4 times a day with subsequent reduction). Multivariate analysis was used to determine the effect of predictors, organism, and treatment on outcomes, 3-month best-spectacle-corrected visual acuity (BSCVA), and infiltrate/scar size. The incidence of adverse events over a 3-month follow-up period was compared using Fisher's exact test. SCUT enrolled 500 patients. One hundred ten patients had P. aeruginosa ulcers; 99 of 110 (90%) enrolled patients returned for follow-up at 3 months. Patients with P. aeruginosa ulcers had significantly worse visual acuities than patients with other bacterial ulcers (P = 0.001) but showed significantly more improvement in 3-month BSCVA than those with other bacterial ulcers, adjusting for baseline characteristics (-0.14 logMAR; 95% confidence interval, -0.23 to -0.04; P = 0.004). There was no significant difference in adverse events between P. aeruginosa and other bacterial ulcers. There were no significant differences in BSCVA (P = 0.69), infiltrate/scar size (P = 0.17), and incidence of adverse events between patients with P. aeruginosa ulcers treated with adjunctive corticosteroids and patients given placebo. Although P. aeruginosa corneal ulcers have a more severe presentation, they appear to respond better to treatment than other bacterial ulcers. The authors did not find a significant benefit with corticosteroid treatment, but they also did not find any increase in adverse events. (ClinicalTrials.gov number, NCT00324168.).

Enhancement of Biogas Production from Bakery Waste by Pseudomonas aeruginosa

OpenAIRE

S. Potivichayanon; T. Sungmon; W. Chaikongmao; S. Kamvanin

2011-01-01

Production of biogas from bakery waste was enhanced by additional bacterial cell. This study was divided into 2 steps. First step, grease waste from bakery industry-s grease trap was initially degraded by Pseudomonas aeruginosa. The concentration of byproduct, especially glycerol, was determined and found that glycerol concentration increased from 12.83% to 48.10%. Secondary step, 3 biodigesters were set up in 3 different substrates: non-degraded waste as substrate in fir...

Novel Multiscale Modeling Tool Applied to Pseudomonas aeruginosa Biofilm Formation

OpenAIRE

Biggs, Matthew B.; Papin, Jason A.

2013-01-01

Multiscale modeling is used to represent biological systems with increasing frequency and success. Multiscale models are often hybrids of different modeling frameworks and programming languages. We present the MATLAB-NetLogo extension (MatNet) as a novel tool for multiscale modeling. We demonstrate the utility of the tool with a multiscale model of Pseudomonas aeruginosa biofilm formation that incorporates both an agent-based model (ABM) and constraint-based metabolic modeling. The hybrid mod...

Structural basis of Zn(II induced metal detoxification and antibiotic resistance by histidine kinase CzcS in Pseudomonas aeruginosa.

Directory of Open Access Journals (Sweden)

Dan Wang

2017-07-01

Full Text Available Pseudomonas aeruginosa (P. aeruginosa is a major opportunistic human pathogen, causing serious nosocomial infections among immunocompromised patients by multi-determinant virulence and high antibiotic resistance. The CzcR-CzcS signal transduction system in P. aeruginosa is primarily involved in metal detoxification and antibiotic resistance through co-regulating cross-resistance between Zn(II and carbapenem antibiotics. Although the intracellular regulatory pathway is well-established, the mechanism by which extracellular sensor domain of histidine kinase (HK CzcS responds to Zn(II stimulus to trigger downstream signal transduction remains unclear. Here we determined the crystal structure of the CzcS sensor domain (CzcS SD in complex with Zn(II at 1.7 Å resolution. This is the first three-dimensional structural view of Zn(II-sensor domain of the two-component system (TCS. The CzcS SD is of α/β-fold in nature, and it senses the Zn(II stimulus at micromole level in a tetrahedral geometry through its symmetry-related residues (His55 and Asp60 on the dimer interface. Though the CzcS SD resembles the PhoQ-DcuS-CitA (PDC superfamily member, it interacts with the effector in a novel domain with the N-terminal α-helices rather than the conserved β-sheets pocket. The dimerization of the N-terminal H1 and H1' α-helices is of primary importance for the activity of HK CzcS. This study provides preliminary insight into the molecular mechanism of Zn(II sensing and signaling transduction by the HK CzcS, which will be beneficial to understand how the pathogen P. aeruginosa resists to high levels of heavy metals and antimicrobial agents.

In vitro antibacterial activity of rifampicin in combination with imipenem, meropenem and doripenem against multidrug-resistant clinical isolates of Pseudomonas aeruginosa.

Science.gov (United States)

Hu, Yi-Fan; Liu, Chang-Pan; Wang, Nai-Yu; Shih, Shou-Chuan

2016-08-24

Multidrug-resistant Pseudomonas aeruginosa has emerged as one of the most important healthcare-associated pathogens. Colistin is regarded as the last-resort antibiotic for multidrug-resistant Gram-negative bacteria, but is associated with high rates of acute kidney injury. The aim of this in vitro study is to search for an alternative treatment to colistin for multidrug-resistant P. aeruginosa infections. Multidrug and carbapenem-resistant P. aeruginosa isolates were collected between January 2009 and December 2012 at MacKay Memorial Hospital. Minimal inhibitory concentrations (MICs) were determined for various antibiotic combinations. Carbapenemase-producing genes including bla VIM, other β-lactamase genes and porin mutations were screened by PCR and sequencing. The efficacy of carbapenems (imipenem, meropenem, doripenem) with or without rifampicin was correlated with the type of porin mutation (frameshift mutation, premature stop codon mutation) in multidrug-resistant P. aeruginosa isolates without carbapenemase-producing genes. Of the 71 multidrug-resistant clinical P. aeruginosa isolates, only six harboured the bla VIM gene. Imipenem, meropenem and doripenem were significantly more effective (reduced fold-change of MICs) when combined with rifampicin in bla VIM-negative isolates, especially in isolates with porin frameshift mutation. Imipenem + rifampicin combination has a low MIC against multidrug-resistant P. aeruginosa, especially in isolates with porin frameshift mutation. The imipenem + rifampicin combination may provide an alternative treatment to colistin for multidrug -resistant P. aeruginosa infections, especially for patients with renal insufficiency.

Protective ventilation reduces Pseudomonas aeruginosa growth in lung tissue in a porcine pneumonia model.

Science.gov (United States)

Sperber, Jesper; Nyberg, Axel; Lipcsey, Miklos; Melhus, Åsa; Larsson, Anders; Sjölin, Jan; Castegren, Markus

2017-08-31

Mechanical ventilation with positive end expiratory pressure and low tidal volume, i.e. protective ventilation, is recommended in patients with acute respiratory distress syndrome. However, the effect of protective ventilation on bacterial growth during early pneumonia in non-injured lungs is not extensively studied. The main objectives were to compare two different ventilator settings on Pseudomonas aeruginosa growth in lung tissue and the development of lung injury. A porcine model of severe pneumonia was used. The protective group (n = 10) had an end expiratory pressure of 10 cm H 2 O and a tidal volume of 6 ml x kg -1 . The control group (n = 10) had an end expiratory pressure of 5 cm H 2 O and a tidal volume of 10 ml x kg -1 . 10 11 colony forming units of Pseudomonas aeruginosa were inoculated intra-tracheally at baseline, after which the experiment continued for 6 h. Two animals from each group received only saline, and served as sham animals. Lung tissue samples from each animal were used for bacterial cultures and wet-to-dry weight ratio measurements. The protective group displayed lower numbers of Pseudomonas aeruginosa (p protective group was unchanged (p protective ventilation with lower tidal volume and higher end expiratory pressure has the potential to reduce the pulmonary bacterial burden and the development of lung injury.

Mutations in 23S rRNA Confer Resistance against Azithromycin in Pseudomonas aeruginosa

DEFF Research Database (Denmark)